One comes to bless the absolute bareness, feeling that here is a pure beauty of form, a kind of ultimate harmony.
George Mallory (18 June 1886 – 8 June/9 June 1924) was a Himalayan mountain climber who famously perished on Mount Everest in 1924.
"Why did you want to climb Mount Everest?" This question was asked of George Leigh Mallory, who was with both expeditions toward the summit of the world's highest mountain, in 1921 and 1922, and who is now in New York. He plans to go again in 1924, and he gave as the reason for persisting in these repeated attempts to reach the top, "Because it's there."
I look back on tremendous efforts & exhaustion & dismal looking out of a tent door on to a dismal world of snow and vanishing hopes - & yet, & yet, & yet there have been a good many things to set the other side.
Why do we travel to remote locations? To prove our adventurous spirit or to tell stories about incredible things? We do it to be alone amongst friends and to find ourselves in a land without man.
This page was last edited on 20 April 2018, at 23:10.


text:
SideTrack: Red Sox WAGs, Katie Couric … and more
Your Tax Dollars
Angelica Feliciano was one of 11 Boston Red Sox wives in attendance at the 18th annual From Fenway to the Runway event, hosted by Linda Henry at Hotel Commonwealth on September 6, benefiting the Red Sox Foundation. Credit: Michael Blanchard
By Olivia Vanni | Boston Herald
PUBLISHED: September 7, 2019 at 6:03 p.m. | UPDATED: September 7, 2019 at 6:25 p.m.
JUST STRIKE-ING: It looks like our Red Sox WAGs also know how to play ball when it comes to fashion, as a slew of the team's significant others hit the runway at Hotel Commonwealth for the 18th Annual From Fenway to the Runway this weekend. This year's event, which benefited the Red Sox Foundation's education and recreation programs, welcomed a number of baseball wives and girlfriends to the catwalk as they strutted their stuff, including: Erin Bradley (the other half to center fielder Jackie Bradley Jr.); Jamie Cashner (pitcher Andrew Cashner); Sarah Esposito (infielder Michael Chavis); Angelica Feliciano (manager Alex Cora); Brittany Owings (infielder/outfielder Chris Owings); Theresa Simunovic (pitcher Colten Brewer); and Gabriela Vazquez (catcher Christian Vazquez).
DROPPING ANCHOR: Broadcast legend Katie Couric and her husband, John Molner, were spotted bouncing around the Seaport late last week. The couple were seen apparently enjoying a pint by the bar at MJ O'Connor's Waterfront, as well as stopping by the Life Is Good office on Melcher Street, where she seems to have snagged some freshly baked cookies from one of the optimistic apparel company's employees. Couric, who's also known for co-founding Stand Up To Cancer, was in our neck of the woods for the INBOUND conference. She took the stage at the Boston Convention & Exhibition Center to moderate a discussion between Jennifer Garner and her Once Upon A Farm co-founder John Foraker, in addition to serving as a spotlight speaker herself and sitting down for a chat about her on-air career and charity work with fellow journalist Sacha Pfeiffer.
GAINE-ING ON US: Speaking of INBOUND spotlight speakers, Chip and Joanna Gaines seem to have had a proper Boston experience while in town for the same conference this past week. The renovation whizzes watched the Red Sox play the Minnesota Twins at Fenway Park on Thursday night — and boy, did the husband-wife duo do it right. While at the game, Joanna captured a couple of moments that showed they were truly trying to channel our Mass. spirit, which included Chip clapping like crazy to the stadium's traditional tune "Sweet Caroline." She also shared footage from her attempt to sneak a few bites of a Dunkin' donut off a table covered with other local classics like Regina's Pizza. The shiplap-happy couple, who we also hear stayed at the Kimpton Nine Zero hotel on Tremont Street during their visit, are most known for their former HGTV show "Fixer Upper." After calling it quits from their TV gig last year, the parents of five have continued to rule their Magnolia empire and its various businesses in their hometown of Waco, Texas.
Olivia Vanni | Columnist

redpajama_set_name: RedPajamaCommonCrawl


text:
Postcodes (for Sat Navs) Office PH16 5PR – Lodges PH16 5PS
Follow the A9 South from Dalwhinnie. In about 20 miles, look for a junction on the right sign posted B847 to Tummel Bridge and Kinloch Rannoch.
Take the B847 and, within about 400 yards, again turn right onto sign posted B847 to Struan, Tummel Bridge and Kinloch Rannoch.
Follow the B847 through Trinafour for about 10 miles to a 'T' junction then turn right sign posted B846 to Kinloch Rannoch and Rannoch Station.
Follow the B846 to Kinloch Rannoch.
Proceed thought the village following the B846. As you start to leave the village, look for the modern medical centre on the right. Immediately opposite this, down a short drive, find the office of the club.
Short Cut:
While travelling South on the A9, (about 13 miles South of Dalwhinnie) look for a junction on the right, sign posted Trinafour. This is a small signpost and easy to miss.
Take this unclassified road for 4.9 miles to join the B847 at Trinafour, then turn right and follow the directions above.
Please be aware that this is a very narrow high level road with some zig zags, sharp bends and steep sections. It is, however, a very scenic route. It will also save you about 7.5 miles. You are advised NOT to take this route if there is snow on the ground or if it is icy.
Follow the A9 North from Perth about 25 miles and look out for a junction on the left, sign posted B8019 to Killiecrankie, Tummel Bridge and Kinloch Rannoch.
Turn left, and follow the B8019 for about a mile and a half to a junction on the left sign posted B8019(B846) to Strathtummel, Tummel Bridge and Kinloch Rannoch.
Continue along the B8019 and to Tummel Bridge (around 10.5.miles) where there is a 'T' Junction. Turn right onto the B846 signposted to Kinloch Rannoch.
Via Aberfeldy
Use the A826 from the A9 at Ballinluig, or the B827 from Crieff to the traffic lights in Aberfeldy. If you're approaching from Ballinluig, turn right at the traffic lights. If you're approaching from Crieff, go straight across, onto the B846 sign posted Weem and Kinloch Rannoch.
Follow the B846 for 20.7 miles to Kinloch Rannoch.
While following the B846 and when you reach the top of the hill, look out for a junction on the left, (about 8.5 miles from Aberfeldy) signposted 'Schiehallion Road'. Turn left and follow this road for another 8.5 miles into the village of Kinloch Rannoch.
Go over the narrow river bridge and turn right onto the B846.
Proceed through the village following the B846. As you start to leave the village, look for the modern medical centre on the right. Immediately opposite this, down a short drive, find the office of the club.
Please be aware that this is a very narrow high level road with some zigzags, sharp bends and steep sections. It is, however, a very scenic route. It will also save you about 3 miles. You are advised NOT to take this route if there is snow on the ground or if it is icy.
The other Route (via Clunie and Foss):
This is a very scenic alternative when travelling from the Pitlochry area but it is not for the faint hearted. If you decide to use this road, please take extra care.
While travelling on the A9 near Pitlochry, look out for the minor junction signposted to Clunie and Foss. This is on the right when travelling north. This is a narrow and winding road that will take you Through Linn of Tummel and along the South side of Loch Tummel to join the B846. Turn right along the B846 through Tummel Bridge to Kinloch Rannoch.
Click here for local train times (Pitlochry)
Click here for local train times (Rannoch)
There are three railway stations within reach of the club.
Blair Atholl (17 Miles) – This is the closest station. It is in the main line to Inverness from Perth and there is a frequent train service, although some of the long distance services do not stop here. There is no bus service from here direct to Kinloch Rannoch and No local taxi service. Unless you are being met, you are better off using Pitlochry Railway Station. It is, however, easier to park here if you are planning an excursion by rail.
Pitlochry (20 Miles) – This station is also on the main line to Inverness from Perth with a frequent service. There is an (infrequent) bus service to and from Kinloch Rannoch run by Elizabeth Yule Transport from the station approach. There are also taxis available close by.
Rannoch Station (16.5 Miles) – Rannoch Station is on the West Highland Line from Glasgow to Fort William. It is extremely isolated in the middle of Rannoch Moor but has a regular service in both directions. Surprisingly, the overnight sleeper from London stops here. Onward travel from this station is by way of the Rannoch Dial-a-bus service, a subsidised pick up service which can be booked to meet the train and will provide transport to the club.
Lines: -
The Inverness to Perth Main Line provides services north to Inverness and on to the North of Scotland including the famous and scenic line to Kyle of Lochalsh. Services South go to Edinburgh and Glasgow. There are direct trains to London and connections for services to the rest of the UK.
The West Highland Line provides services to Fort William and on over the Mallaig Extension to Mallaig. Services on the Mallaig extension include the steam hauled 'Jacobite'. This line (and the carriages used by the 'Jacobite') featured in the Harry Potter films. Southwards, the line goes to Glasgow with connections to the rest of the UK.
Click here for the local bus time table.
Elizabeth Yule Transport provides the only bus service to Kinloch Rannoch. This is service 82 although on Mondays, Wednesdays and Fridays, in the afternoon, there is one service via Blair Atholl (service 887). In Kinloch Rannoch, the bus turns around in the entrance to the Macdonalds Hotel.
Dial a Bus: This is a government subsidised service operating within Tummel and Rannoch between Rannoch Station and Tummel Bridge. The service will pick you up and drop you off at any point within the prescribed area. Services need to be booked in advance and you may have to share the vehicle if someone else is going the same way. There are two providers for the Dial-a-bus service. 'Broon Buses and Taxis (01882 632418)' and 'Highland Travel (01882 633398'). More Info
There are six airports within a reasonable distance of The Loch Rannoch Highland Club.
Distance from Kinloch Rannoch
Airport website
Scheduled Destinations
Onward travel
Edinburgh 92 miles http://www.edinburghairport.com/ Edinburgh Airport is a busy airport with scheduled flights to numerous destinations, mainly in the UK and Europe. Click here for destination information By Road - via the M90 towards Perth
By Tram to Edinburgh Haymarket Rail Station where there are direct trains to Pitlochry.
Glasgow 117 miles http://www.glasgowairport.com/ Glasgow Airport is a busy airport with scheduled flights to numerous destinations, mainly in the UK and Europe. Click Here for destination information By Road - via the M8 and M80 towards Perth
By service Bus to Glasgow Queen Street Station where there are trains to Pitlochry and Rannoch Station
Inverness 87 miles http://www.invernessairport.co.uk/ Inverness Airport is a smaller airport with scheduled flights to a number of destinations, mainly in the UK and Amsterdam Click here for destination infomation By Road - via A96 and A9 towards Pitlochry
By Bus or Taxi to Inverness then rail to Pitlochry
Glasgow Prestwick 140 miles http://www.glasgowprestwick.com/ Glasgow (Prestwick) Airport has scheduled flights to numerous destinations, in Europe. It is located between Troon and Ayr, South West of Glasgow Click here for destination information By Road - via A77 and M77 towards Glasgow, then by M8 and M80 towards Perth
By Rail - Direct Rail Link from the airport to Glasgow Central, then from Glasgow Queen Street to Pitlochry or Rannoch Station
Dundee 74 miles http://www.hial.co.uk/dundee-airport/ There is currently only one scheduled service to Dundee airport. This is to and from London Stanstead Airport Click here for destination information By Road - via A85 and A90 to Perth then via The A9 towards Pitlochry
By Rail - Bus or Taxi to Dundee Railway Station then train to Pitlochry changing at Perth.
Perth 55 miles https://perthairport.co.uk/ There are currently no scheduled services to and from Perth airport. It is, however, a busy centre for general aviation. There are no scheduled services from Perth Airport. By Road - A94 to Perth then A9 towards Pitlochry
By Rail - Bus or Taxi to Perth Railway Station then train direct to Pitlochry


Auschwitz, Birkenau, Treblinka and Theresienstadt (Terezin): Images from German concentration camps located in Poland and the Czech Republic during World War II. The structures in Treblinka were torn down during World War II. A monument was subsequently built to memorialize those who died in the camp. The individual stones with engraved names are the towns and villages from which individuals were forcibly removed to Ttreblinka...to be condemned to death. The photos include a section of a Holocaust Memorial in Warsaw. Terezin, the last pictured site, is located in the Czech Republic.


text:
Мамертинци су били најамници италијанскога порекла, које је најпре унајмио краљ Сиракузе Агатокле. Након Агатоклове смрти 289. п. н. е. остало је много незапослених најамника на целој Сицилији. Мамертинци су 288. п. н. е. заузели Месану, а њено становништво су побили или истерали. Месану су користили као базу за пиратске нападе и базу за пљачкашке походе на оближња насеља на Сицилији. Због пљачкања избио је 265. п. н. е. рат Мамертинаца и Сиракузе. Мамертинци су губили рат, па су затражили помоћ Рима. Када се Рим укључио у рат на страни Мамертинаца Картагина се укључила као савезник Сиракузе, па је локални сукоб прерастао у Први пунски рат.

Заузимање Месене

Мала група најамника ушла је у грчку насеобину Месану (данашња Месина). Месана је била стратешки значајна јер је заједно са Регијем на другој страни контролисала стратешки важан Месински мореуз, тј теснац између Сицилије и Италије. Становници Месане су угостили најамнике ништа не сумњајући. Након неког времена најамници су почели да планирају да заузму град. Једне ноћи најамници су изненадили своје домаћине, побили већину становништва и заузели град за себе. Преживеле становнике Месане истерали су из града, а имовину и жене су задржали за себе. Након освајања Месане 288. п. н. е. себе су назвали Мамертинци по осканском богу рата Мамеру (идентичан богу Марсу).

Владање над североисточном Сицилијом

Мамертинци су држали Месану преко 20 година. Град је претворен у пиратску базу, одакле су кретали у нападе и пљачке. Пљачкали су и оближња сицилијанска насеља. Заробљавали су неопрезне трговачке бродове, а плен су носили у своју базу. Заробљавали су и људе тражећи за њих откуп. У то доба ковали су и свој новац, на коме су биле слике њихових богова. Постали су богати и моћни и почели су да путују и дубље, чак до Геле. Мамертинци су многима наметнули плаћање данка као заштите од пљачке.

Пир од Епира интервенише на Сицилији

Народ Сиракузе је 278. п. н. е. тражио помоћ од Пира од Епира. Пир је ратовао против Картагињана, а Мамертинци су били њихови савезници. Пир од Епира је победио Мамертинце и уништио им је много упоришта, али није намеравао да им заузме град. Уместо тога сукобљавао се више са Картагињанима на западу Сицилије. Након некога времена Пира су почели да напуштају савезници, па је напустио Сицилију.

Хијерон II од Сиракузе побеђује Мамертинце

Међутим њихове активности и пљачке нису прошле неопажене. Сиракушки насељеници су се жалили. Хијерон II од Сиракузе окупио је војску са којом је намеравао да ослободи Сицилију пљачкаша. Хијеронова грађанска војска наишла је на Мамертинце када су се они приближавали Сиракузи. Хијерон је напред послао најпре своје недисциплиноване најамнике и дозволио да их Мамертинци побију. Ослободивши се оних којима није веровао Хијерон се вратио у Сиракузу, где је почео да тренира своју грађанску војску. Када је увежбао војску кренуо је у нови обрачун са Мамертинцима. Сукобио се с њима на реци Лонган у низији Миле и лако их је победио. Било је то између 269. п. н. е. и 265. п. н. е. Мамертинци нису били навикли на велике одлучне битке, а били су и несмотрени након победе над Хијероновим најамницима. Хијерон II од Сиракузе је у бици заробио вође Мамертинаца, а остали Мамертинци су побегли у Месану.

Картагињански гарнизон спашава Мамертинце

Хијерон је ограничио активности Мамертинаца, па су се они нашли у ужасној ситуацији. Хијерон II од Сиракузе је након победе у бици на Логану окупио војску са циљем да опседа Месану. Мамертинци су затражили помоћ од оближње картагињанске флоте, која се налазила на Еолским острвима. Картагињани су са својим гарнизоном ушли у Месану, па је Хијерон одустао од опсаде. Картагињани нису били спремни да допусте да Сиракузе контролише тако важан теснац, попут Месинскога. Сиракужани су се након тога повукли не желећи да се сукобе са Картагињанима.

Мамертинци се нису осећали лагодно под картагињанском заштитом и са картагињанским гарнизоном, пошто су Картагињани контролисали месенски мореуз. Међутим сами нису имали довољно снага да се изборе та независност, поготово када више нису имали подршку из Регија, који су Римљани очистили од побуњеника. Међу Мамертинцима једни су се залагали за склапање новога споразума са Картагином, којим би била гарантована њихова независност. Међутим превагу је однела страна, која се залагала да се потражи римска заштита, а да се од картагињанскога гарнизона тражи да напусте град. Мамертинци су након тога затражили заштиту Рима. Римљани најпре нису желели да помажу војницима, који су неправедно отели град од њихових становника, а поготово што је постаојао сличан случај са кампанијским најамницима, који су били отели Региј на другој страни месенскога теснаца. Ипак пошто нису желели да се картагињанска хегемонија рашири још даље по Сицилији и приближи Италији одлучили су да постану савезник Мамертинаца. Као одговор на тај римски потез Сиракуза је ступила у савез са Картагином. Пошто су у сукоб Мамертинаца и Сиракузе били увучени Рим и Картагина стекли су се услови за већи рат, па је тај мањи сукоб ескалирао у Први пунски рат. Након Првога пунскога рата Мамертинци су се изгубили из историје.

Види још
 Пиров рат
 Први пунски рат

Извори

 Полибије, Историје
 Диодор са Сицилије, Историјска библиотека
 Плутарх, Пир
 H. H. Scullard, "Carthage and Rome",in The Cambr. Ancient History (Cambr. University Press. 1989), vol.7.2.

Пиров рат

redpajama_set_name: RedPajamaWikipedia


text:
Modelling and measurement of the absolute level of power radiated by antenna integrated THz UTC photodiodes
Michele Natrella, Chin-Pang Liu, Chris Graham, Frederic van Dijk, Huiyun Liu, Cyril C. Renaud, and Alwyn J. Seeds
Michele Natrella,1 Chin-Pang Liu,1 Chris Graham,1 Frederic van Dijk,2 Huiyun Liu,1 Cyril C. Renaud,1 and Alwyn J. Seeds1,*
1UCL Electronic and Electrical Engineering, Torrington Place, London WC1E 7JE, UK
2III-V Laboratory, 1, avenue Augustin Fresnel, RD128 F-91767 Palaiseau Cedex, France
*Corresponding author: a.seeds@ucl.ac.uk
M Natrella
C Liu
C Graham
F van Dijk
H Liu
C Renaud
A Seeds
Michele Natrella, Chin-Pang Liu, Chris Graham, Frederic van Dijk, Huiyun Liu, Cyril C. Renaud, and Alwyn J. Seeds, "Modelling and measurement of the absolute level of power radiated by antenna integrated THz UTC photodiodes," Opt. Express 24, 11793-11807 (2016)
Accurate equivalent circuit model for millimetre-wave UTC photodiodes (OE)
High performance waveguide uni-travelling carrier photodiode grown by solid source molecular beam epitaxy (OE)
Traveling-wave Uni-Traveling Carrier Photodiodes for continuous wave THz generation (OE)
Terahertz and X-ray Optics
Coupling efficiency
Phase measurement
Reflection coefficient
Transmission measurement
Far infrared or terahertz (040.2235)
Semiconductors (130.5990)
Photodiodes (230.5170)
Optoelectronics (250.0250)
Propagation (350.5500)
Waves (350.7420)
Original Manuscript: March 23, 2016
Revised Manuscript: May 1, 2016
Manuscript Accepted: May 2, 2016
2. Device 3D full-wave modelling
4. Modelling and measurement of the absolute power radiated by a bow-tie antenna integrated UTC
We determine the output impedance of uni-travelling carrier (UTC) photodiodes at frequencies up to 400 GHz by performing, for the first time, 3D full-wave modelling of detailed UTC photodiode structures. In addition, we demonstrate the importance of the UTC impedance evaluation, by using it in the prediction of the absolute power radiated by an antenna integrated UTC, over a broad frequency range and confirming the predictions by experimental measurements up to 185 GHz. This is done by means of 3D full-wave modelling and is only possible since the source (UTC) to antenna impedance match is properly taken into account. We also show that, when the UTC-to-antenna coupling efficiency is modelled using the classical junction-capacitance/series-resistance concept, calculated and measured levels of absolute radiated power are in substantial disagreement, and the maximum radiated power is overestimated by a factor of almost 7 dB. The ability to calculate the absolute emitted power correctly enables the radiated power to be maximised through optimisation of the UTC-to-antenna impedance match.
Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Photonic THz emitters based on antennas integrated with uni-travelling carrier photodiodes (UTC-PDs) [1–9], are promising candidates for the realisation of sources within the lower part of the THz spectrum (100 GHz – 3 THz) [10–12]. The maximisation of the power extracted from a UTC is central to the successful realisation of a photonic THz emitter. When the UTCs are integrated with antennas, such maximisation entails the optimisation of the energy coupling between UTC and antenna. In the long history of RF and microwave antenna engineering, the impedance match between antenna and source has been shown to have a critical role. However, for antenna integrated photodiodes, this aspect has so far received little attention. To be able to calculate the absolute power radiated by antenna integrated UTCs and optimise the coupling efficiency between UTC and antenna, detailed knowledge of the UTC impedance is required. In our recent work [13] we have presented an experimental and semi-analytical study of waveguide UTC impedance and introduced an accurate circuit model verified up to 110 GHz. Although lumped element analysis of 15 µm long InP UTCs can, in principle, be employed up to about 400 GHz, where the effective wavelength is 20 times the UTC length, the results need to be validated to be extended up to such frequencies. In this paper we extend the knowledge of UTC impedance and photo-response up to 400 GHz, by performing for the first time 3D full-wave modelling of the detailed UTC-PD structure, including all epitaxial layers. Knowing the source and antenna impedance, and hence the coupling efficiency, up to the sub-millimetre wave frequency range, means that the absolute value of radiated power can be calculated up to such high frequencies. If the coupling efficiency is unknown, the radiated power cannot be predicted.
Furthermore we demonstrate prediction of the emitted power by modelling, using CST Microwave Studio, and measuring the power radiated by a 760 µm long bow-tie antenna integrated UTC at frequencies up to 185 GHz. We also show that the radiated power, calculated, based on the classical junction-capacitance/series-resistance concept, is in substantial disagreement with the measurements, which proves that a significant amount of radiated power can be lost due to sub-optimum photodiode to antenna impedance matching. The capability of predicting the radiated power correctly, raises the possibility of enhancing the radiated power by designing antennas approaching, as closely as possible, the maximum power transfer condition, realised when the load impedance is equal to the complex conjugate of the source impedance. It is important to bear in mind that when the source impedance is complex, as is the case for the UTC, the minimisation of the reflection coefficient as a criterion to maximise the real power transferred to the load (antenna) cannot be employed. Complex conjugate matching has to be used instead.
While the antenna impedance is relatively easy to calculate and is established during the design stage, the modelling and evaluation of the UTC impedance is a far more challenging task. Knowing accurately the physical properties of all the semiconductor materials making up a UTC photodiode is essential to obtain valid results from modelling and such knowledge is difficult to achieve. UTCs contain ternary (e.g. InGaAs) and quaternary (e.g. InGaAsP) materials, with different element concentrations and different doping levels; the values of electrical permittivity and especially electrical conductivity for these materials can only be estimated. Furthermore, we showed in [13] that quantum mechanical effects governing the electron transport from the absorber to the collection layer, through the spacers, can affect the conduction properties in a way that, at a macroscopic scale, is reflected in changes in bulk material properties, such as resistivity and electrical permittivity. For these reasons, we employ the results of our previous work [13] which will help us assess and refine the material physical properties to employ in the full-wave modelling and simulation, which in turn enables the S11 and the UTC impedance to be evaluated up to frequencies not attainable by measuring equipment.
The waveguide UTCs we model in this work were fabricated at III-V Lab and have the same structure as those studied in our recent paper [13], therefore the modelling here is also focused on 3 x 15 µm2 and 4 x 15 µm2 active area devices. The device epitaxial structure is given again in Table 1 while Fig. 1 shows photographs of two sample photodetectors, with active area equal to 3 x 15 µm2 and 4 x 15 µm2 respectively.
Table 1. Layer structure of the UTCs provided by III-V Lab.
Fig. 1 Photograph of two sample UTCs, with 3 x 15 µm2 and 4 x 15 µm2 area. The devices are integrated with coplanar waveguide contact pattern for the use of air coplanar probes.
In [13] we introduced a new equivalent circuit model (Circuit 3), illustrated in Fig. 2, that provides very good agreement with UTC impedance and photo-response measured up to 110 GHz and 67 GHz respectively, for all of the four examined scenarios, e.g. 3 x 15 µm2 UTC at 0 V and −2 V bias, 4 x 15 µm2 UTC at 0 V and −2 V bias. Table 2 summarises the optimised circuit elements for the four scenarios. The spacers are modelled as two RC parallel circuits (R2C2 and R3C3). The R4C4 parallel represents the carrier collection layer, while R1 takes into account the resistive effects of doped materials and ohmic contacts. Additional parameters employed to model the UTCs (such as electron overshoot velocity in the collection layer, diffusion constant of electrons in the absorber, thermionic emission velocity, carrier recombination lifetime in the absorber) can be found in [13].
Fig. 2 Relation between the new equivalent circuit and the UTC structure.
Table 2. Summary of the equivalent circuit optimised parameters.
The parasitic inductance Lp is principally due to the coplanar waveguide contact pads, deposited to enable the use of air coplanar probes. The value of Cp is very small and can be associated with the capacitive coupling between the n- and p-contact metal pads. Accurate evaluation of the parasitic effects in the structure can only be achieved by full-wave modelling, especially above 110 GHz.
The 3D full-wave modelling work has been performed in CST STUDIO SUITE. As reference source for the material properties, the CST STUDIO SUITE material database was employed together with the information available in [14,15] and in the on-line electronic archive of the Ioffe Physico-Technical Institute. The optimised parameters of the equivalent circuit and their relation with the device structure, discussed in [13] and here illustrated in Fig. 2, are also employed to set the material properties (i.e. conductivity and relative electrical permittivity) in CST.
The electrical conductivities and relative electrical permittivities of the layers contributing to the UTC series resistance are summarised in Table 3. The p- and n-ohmic contact resistances have been taken into account in the CST model by inserting thin layers of appropriate conductivity between the n/p-contact layers and the gold pads; we have used specific contact resistance values of 5.5 × 10−7 Ω cm2 and 8 × 10−6 Ω cm2 obtained by deposition of Ti/Pt/Au on Zn‐doped 5 × 1018 cm−3 p‐In0.53Ga0.47As and S‐doped 1 × 1018 cm−3 n‐InP respectively, reported in the literature [16]. The ohmic contact resistance can be experimentally evaluated through transmission line model measurements [17,18] though it was not possible to carry out this type of measurements on our UTCs as no samples with the required contact pad patterns were available.
Table 3. Conductivities used in the full-wave modelling for the layers contributing to the UTC series resistance. The relative electrical permittivity values are also shown, although they play a very marginal role for these layers.
A CST model, as in Fig. 3, has been used to calculate the device DC resistance and verify that the conductivities given in Table 3 and the employed specific contact resistances actually produce a total device resistance of 15 Ω for the 3 x 15 µm2 UTC.
Fig. 3 Cross section of the UTC CST model, showing the current flowing through all the ridge layers and through the InP n-layer to reach the n-metallisation. The simulation shows that only a limited area of the interface between InP n-layer and n-metallisation is actually crossed by the current. Absorber, spacer and depletion layers in the ridge have been replaced by a layer of perfect electric conductor as they do not contribute to the device series resistance.
It has to be noted that the assessment of the contribution provided to the device series resistance by the n-ohmic contact and the n-InP contact layer itself, is not a trivial geometrical problem. The area covered by the two n-metallisation pads is quite large (greater than 20 x 15 µm2 each pad). Therefore, if the whole area was considered to calculate the n-ohmic contact resistance, then a value of only 1.3 Ω would be obtained. Actually, only a limited area of the pads is crossed by the electric current and hence the resistance offered by the ohmic contact is larger, i.e. 3.5 Ω. The current flows vertically through all the ridge layers and then through the InP n-layer to reach the n-metallisation. Here the intensity of the current flowing through the n-ohmic contact decreases gradually as we move further away from the p-ridge; in practice an effective area of 7.5 x 15 µm2 for each of the two n-ohmic contacts can be identified, which would provide the same resistance of 3.5 Ω if uniformly crossed by the current. Absorber, spacer and depletion layers in the ridge have been here replaced by a layer of perfect electric conductor in this CST model, as they do not contribute to the device series resistance. This analysis highlights that having a high conductivity for the n-contact layer plays a critical role for the achievement of a low device series resistance.
The CST model has also been used to verify whether the device series resistance actually scales down by a factor 3/4 for the 4 x 15 µm2 UTC; it was found, as already suggested in [13], that the 4 x 15 µm2 UTC series resistance is 12.7 Ω which is slightly larger than (3/4) x 15 Ω ( = 11.2 Ω) and this is consistent with the fact that in reality only the resistance of the layers making up the ridge scales down by (3/4) while that of n-contact layer and n-ohmic contact does not. The properties of the two spacers and the collection layer are dictated by the optimised circuit elements R2, C2, R3, C3, R4 and C4 of the equivalent circuit in Fig. 2, and are summarised in Table 4. It is important to bear in mind that these properties are not intended to represent the actual bulk properties of the materials making up the layers concerned but are the results of the model we have introduced in [13] to explain the effects observed in the experimental data. As can be seen in Table 4, the relative electrical permittivity of the layers, except the absorption layer, is slightly different for the two different bias values (0 V and −2 V). This takes into account the small capacitance change introduced by the applied reverse voltage. Although the changes in capacitance are due to variations of the depletion region thickness, we have preferred to maintain the model geometry unchanged and account for the effect by means of an equivalent permittivity variation. Since the absorption layer only provides a marginal resistive contribution, its permittivity was not changed. The passivation layer was Benzocyclobutene (BCB) and was modelled as a polymer dielectric with an electrical permittivity of 2.5. The substrate was modelled with standard 12.5 permittivity indium phosphide (InP) while for the metal pads the default CST gold model (conductivity of 4.561 x 107 (Ωm)−1) was employed. Very thin layers of platinum (conductivity of 9.52 x 106 (Ωm)−1) and titanium (conductivity of 2.32 x 106 (Ωm)−1) were also included in the model between the polymer and the CPW gold but were not inserted between the UTC n/p- contact layers (InGaAs/InP) and the gold because at these locations, as mentioned previously, ad hoc layers were introduced to take the ohmic contact resistances into account.
Table 4. Material properties of the two spacers and the collection layer derived by the optimised circuit elements R2, C2, R3, C3, R4 and C4 of Circuit 3. The absorber properties are also shown, although this layer only provides a marginal resistive contribution.
The CST model including the whole of the cleaved chip and the CPW pads is illustrated in Fig. 4. Figure 5 shows additional details of the area near the UTC, including the n-contact layer mesa and the optical waveguide, while a further magnified cross section view is given in Fig. 6, showing details of the layers making up the ridge.
Fig. 4 CST model including the whole of the cleaved chip and the CPW pads.
Fig. 5 Model details of the area near the UTC, including the n-contact layer mesa and the optical waveguide.
Fig. 6 Magnified cross section view showing details of the layers making up the UTC ridge.
Since the chip was placed on a brass mount during the measurement, a perfect electric conductor (PEC) plane was used as boundary condition underneath the InP substrate (Zmin), while all the other boundaries were surrounded by vacuum. The excitation source, highlighted in red in Fig. 4, was placed on the CPW signal pad and connected to the ground pads through ideal one-dimensional PEC wires (blue lines in Fig. 4) which introduced no parasitic capacitance; to reduce the current loop inductance introduced by the wires, the loop areas were kept as small as possible. The excitation source is a CST "discrete port", essentially representing a Norton (or Thevenin) equivalent with a 50 Ω impedance. The CST discrete ports provide accurate results when their size is much smaller than the wavelength; in our model the discrete port is 1 µm long. It should be noted that the hardware used for this work enabled the simulation of very large models, up to a few hundred million mesh cells, containing geometrical features extremely small compared to the bounding box size; for instance, the extremely thin spacer layers shown in Fig. 6, were discretized by 4 mesh lines in the vertical direction.
3.1 S11 and impedance 3D full-wave modelling
The S11 and impedance of the 3 x 15 µm2 area UTC at 2 V reverse bias were calculated in CST up to 400 GHz and are shown in Fig. 7, together with the experimental data up to 110 GHz, reported in [13], and with the results obtained using the new circuit shown in Fig. 3, also introduced in [13]. The values shown in Table 2 are employed for the circuit parameters; these parameters include the value of 16 pH for the parasitic inductance Lp which resulted from fitting the S11 measured in the W-band [13]. We investigated the effect of the CPW pads on the S11 both experimentally and using CST. We found that the CPW pads have no or small effect on the measured S11 below 67 GHz, whereas they start having a significant effect in the W-band; the effect becomes dramatic above 110 GHz. The CST modelled S11 and impedance shown in Fig. 7 have been calculated in CST excluding the effect of the CPW pads and therefore refer to the UTC alone. This is important in view of the UTC to antenna matching optimisation, since the impedance seen from the terminals of an antenna integrated with the UTC does not include the CPW pads.
Fig. 7 S11 and impedance of the 3 x 15 µm2 area UTC at −2 V bias, calculated using CST, compared with the experimental data and with the results obtained using the equivalent circuit (including the overestimated parasitic inductance Lp = 16 pH). The amended value of 6.5 pH for Lp provides excellent agreement between circuit and CST up to 400 GHz.
The magnitudes of the measured S11 and the S11 obtained with CST and the equivalent circuit are all in excellent agreement up to 90 GHz and good agreement between 90 GHz and 110 GHz. The phases are all in excellent agreement up to 67 GHz, then measurement and circuit phases maintain good agreement up to 110 GHz, while CST phase begins to depart. Above 110 GHz the disagreement between the equivalent circuit and CST S11 becomes increasingly significant. This disagreement is entirely due to the value of the inductance Lp in the circuit which is too high (16 pH), as can be seen clearly from the reactance in Fig. 7 which switches from capacitive (i.e. < 0) to inductive (i.e. > 0) at 255 GHz for the circuit while it is still slightly capacitive at 400 GHz for the CST result. Importantly, if Lp is reduced to 6.5 pH, the S11 and impedance obtained with CST and the circuit are identical up to 400 GHz. As mentioned above the value of 16 pH for Lp in [13] resulted from the need to force the circuit S11, particularly its phase, to match the S11 measured between 75 GHz and 110 GHz. However, as mentioned previously, the S11 measured in the W-band is affected by the effect of the CPW and most importantly by inevitable uncertainty of the SOLT calibration on wafer at these frequencies [19–22]. It is important to bear in mind that for the other three scenarios (e.g. 3 x 15 µm2 UTC at 0 V, 4 x 15 µm2 UTC at 0 V and 4 x 15 µm2 UTC at −2 V), as well as for the result in Fig. 7, the amended 6.5 pH inductance would provide excellent agreement between circuit and CST results up to 400 GHz.
3.2 Frequency photo-response 3D full-wave modelling
3D full-wave modelling was also employed to calculate the UTC frequency dependent photo-response. The frequency response calculated in CST only represents the RC-limited response; the transit-time limited response contribution is incorporated using the transit-time responses calculated in [13]. For the modelling of the frequency response, the discrete port used as excitation source for the S11 calculation was replaced with a 50 Ω load, representing the lightwave component analyser input impedance to which the RF power generated by the UTC is delivered. Also, an ideal current source was placed across collection layer, spacers and absorber, connecting the heavily doped waveguide and ridge layers. The effect of the overestimated parasitic inductance (Lp = 16 pH) on the UTC photo-response is shown in Fig. 8; here the RC-limited response calculated with full-wave simulation is compared with the experimental data [13] and with the circuit RC-limited response for both the overestimated value of parasitic inductance (Lp = 16 pH) and the amended value (Lp = 6.5 pH). As for the case of S11 and impedance calculation, the too high initial value of the inductance Lp (16 pH) is entirely responsible for the disagreement between the circuit and CST results. Remarkably, as for S11 and impedance, the amended value of 6.5 pH for Lp also provides a very good agreement between Circuit 3 and CST RC-limited frequency response up to 400 GHz, as also shown in Fig. 8. The reason why a greater value of inductance Lp provides a better power transfer to the 50 Ω RL up to at least 300 GHz is that, such an inductance (16 pH) tunes the capacitive component of the UTC reactance more efficiently than the smaller value (6.5 pH).
Fig. 8 Comparison between RC-limited response calculated with full-wave simulation (continuous black line) and experimental data (continuous blue line). The RC-limited response calculated with the equivalent circuit, using both the initial value of parasitic capacitance LP = 16 pH (dash-dot green line) and the amended value 6.5 pH (dashed red line) are also shown.
If we now use the CST RC-limited response to calculate the overall UTC frequency response, by incorporating the transit-time limited response calculated in [13], we obtain the results shown in Fig. 9 for the 3 x 15 µm2 device.
Fig. 9 Comparison between measured frequency photo-response and overall frequency photo-response calculated combining the full-wave modelling RC-limited response with the transit-time limited responses calculated in [13], for the case of a 3 x 15 µm2 area UTC. The inset is a magnified view of the responses in the frequency range 0 GHz to 80 GHz.
III-V Lab also fabricated a 3 x 15 µm2 area UTC integrated with a bow-tie antenna with a gold screen deposited underneath the InP substrate, shown in Fig. 10(a); we measured the substrate thickness which was 200 µm. The gold screen was not intended to operate as a ground plane for the antenna emission, therefore the whole antenna chip did not represent an optimum design for radiation with a ground plane. However, the antenna represented an opportunity to investigate whether the knowledge of the UTC impedance, in conjunction with antenna full-wave modelling, could provide a good prediction of the absolute level of power radiated over the frequency range. Considering the antenna length (about 760 µm) and the InP relative electrical permittivity (12.5), the theoretical half-lambda resonance of the antenna on a semi-infinite InP substrate, would be around 76 GHz.
Fig. 10 a) Bow-tie antenna integrated UTC with a ground plane, provided by III-V Lab. The photodetector area is 3 x 15 µm2 and the antenna-chip approximate geometrical details are shown in the picture; b) CST model of the bow-tie antenna with a gold ground plane.
The power emitted by the antenna integrated UTC in Fig. 10(a), was measured between 65 GHz and 185 GHz with a basic heterodyne experimental arrangement using two free running lasers. The optical power applied to the UTC was measured with a power meter and was 50 mW. The UTC was still operating in the linear region and no sign of saturation was observed. The UTC was biased at −2 V and exhibited a DC photocurrent of 7.2 mA, corresponding to a 0.144 A/W responsivity. A Thomas Keating (TK) power meter system was used to measure the radiated power. The antenna chip was also modelled in CST, as shown in Fig. 10(b), over the frequency range 50 GHz to 185 GHz.
The total power emitted by an antenna depends on the efficiency of energy coupling with the driving source and on the radiation efficiency. The former defines the fraction of power made available by the source that is accepted by the antenna, while the latter determines the fraction of power accepted by the antenna that is coupled into free space. The antenna directivity, on the other hand, describes the angular distribution of the radiated power.
The bow-tie Antenna 3D radiation pattern (directivity in dBi) calculated in CST, is shown in Fig. 11 for four frequencies of interest, i.e. 67.5 GHz, 116.3 GHz, 145 GHz and 180 GHz. The radiation patterns show how part of the emitted power, especially at 116.3 GHz, is radiated almost along the XY plane, or at least at very shallow angles, and would not be captured by a power meter positioned in front of the antenna in a real measurement. For this reason the power radiated within different rectangular solid angles along the Z direction has also been calculated, to enable a more realistic comparison with the experimental results.
Fig. 11 Bow-tie antenna 3D radiation pattern calculated in CST.
The maximum transfer of power between source and antenna occurs at the frequencies for which the antenna impedance is equal to the source (UTC) impedance complex conjugate. Therefore local maxima of radiated power should be expected at the frequencies where source and antenna reactance have similar absolute value and opposite sign and the impedance real parts are comparable. The level of radiated power is also affected by other factors including radiation efficiency, solid angle considered for the radiated power calculation and transit-time limited response of the UTC.
In Fig. 12 we plot the measured radiated power and the radiated power calculated when the UTC impedance is simply taken into account employing the classical junction-capacitance/series-resistance concept; in this case the photodiode reactive component is only attributed to a single capacitance of 17 fF, i.e. the junction capacitance based on the device geometry and material properties. The power radiated at each frequency by an antenna is proportional to the squared amplitude of the current flowing into the antenna at that frequency; on the other hand the current flowing into the antenna depends on the match/mismatch between antenna impedance and source impedance. The measured 7.2 mA DC photocurrent can be used as a reference level and the transit-time limited response used to calculate the overall photo-current response in Fig. 9, can be considered to take the transit-time effect into account. The radiated power was calculated for different rectangular solid angles along the Z axis. Such solid angles are defined by two planar angles relative to the Z axis, one in the XZ plane and the other in the YZ plane. For instance the 90 x 90 degrees rectangular solid angle in Fig. 12 is identified by an angle of 45° with respect to the Z axis, lying within the XZ plane, and an angle of 45° in the YZ plane. The solid angle "TK window" in Fig. 12 refers to the solid angle subtended by the 40 x 30 mm2 Thomas Keating window with respect to the emitter positioned 33 mm apart; the solid angle "TK window" is hence identified by a 31.2° angle in the XZ plane and 24.4° in the YZ plane.
Fig. 12 Comparison between measured radiated power and radiated power calculated when the UTC impedance is taken into account using the classical junction-capacitance/series-resistance concept. The power is also calculated within rectangular solid angles along the Z axis.
The trends of measured and calculated power over the frequency range in Fig. 12 seem correlated; the peaks of measured power at 74 GHz and 140 GHz seem to correspond to the peaks of calculated power at 71 GHz and 148 GHz, and the narrow peak of measured power at 105 GHz seem to correspond to the feature in the calculated power around 115 GHz. However, the peak of radiated power calculated within the solid angle "TK window" at 71 GHz is 6.6 dB greater than the peak of power measured at 74 GHz (0.8 dBm vs. −5.8 dBm, i.e. 1202 µW vs. 262 µW). The peak of radiated power calculated within the solid angle "TK window" at 148 GHz is 4.7 dB greater than the peak of power measured at 140 GHz (−8.1 dBm vs. −12.8 dBm, i.e. 155 µW vs. 53 µW). This disagreement is significant and proves that a design based on the classical junction-capacitance/series-resistance assumption would have led to a substantial overestimation of the radiated power obtainable.
To perform a thorough calculation of the absolute level of power emitted by the antenna, the coupling efficiency between the antenna and the UTC must be properly taken into account; this can now be evaluated using the results of the experimental and numerical analysis of UTC impedance, discussed above and in [13]. The real and imaginary parts of the antenna impedance are plotted in Fig. 13 and compared with those we obtained for the 3 x 15 µm2 area UTC at −2 V bias.
Fig. 13 Comparison between real and imaginary parts of the bow-tie antenna impedance and those measured and calculated for the 3 x 15 µm2 area UTC at −2 V bias.
In Fig. 14 we plot the measured radiated power and the radiated power calculated when the UTC to antenna coupling efficiency is based upon our knowledge of the UTC impedance, plotted in Fig. 13. The main maxima of power accepted by the antenna occur at frequencies where the imaginary parts of UTC and antenna impedance have about same absolute value and opposite sign and the real parts are comparable (i.e. 67 GHz, 145 GHz, 168 GHz), as reflected in the calculated emitted power plotted in Fig. 14. On the other hand there are frequencies where, despite the impedance imaginary parts having similar absolute value and opposite sign, there is no peak of radiated power because the impedance real parts are greatly different; this situation is verified at 87 GHz, where the impedance real part is 20 Ω for the UTC and over 1 kΩ for the antenna, and at 173 GHz where the impedance real part is 15 Ω for the UTC and 190 Ω for the antenna. The importance of the coupling efficiency between source and antenna can be seen at 180 GHz where the radiated power calculated within an increasingly narrow solid angle does not show any maximum although the directivity pattern is favourable, as shown in Fig. 11, and the impedance real parts of UTC and antenna are fairly close (15 Ω vs 40 Ω). The reason is that the UTC and antenna reactance are both capacitive at 180 GHz, therefore little power is accepted by the antenna. The small sharp local maximum calculated at 116 GHz, is due to a rapid increase of the antenna resistance that equals the UTC resistance, while the antenna reactance peaks to zero. This maximum tends to disappear as an increasingly narrow solid angle is considered, because, at this frequency, the power is mostly radiated at very shallow angles with respect to the antenna plane, as can be seen in Fig. 11.
Fig. 14 Comparison between measured radiated power and radiated power calculated when the UTC to antenna coupling efficiency is based on our achieved knowledge of the UTC impedance, plotted in Fig. 13.
A direct comparison between the radiated power calculated in CST within the solid angle "TK window" and the measured radiated power, is shown in Fig. 15 in µW on a linear scale. The trends of measured and calculated power over the frequency range are clearly correlated and show a good agreement. The peaks of measured power at 74 GHz and 140 GHz seem to correspond to the peaks of calculated power at 67 GHz and 145 GHz. The small peak of measured power at 105 GHz seems to correspond to the feature in the calculated power around 115 GHz; we found that both position and prominence of this calculated feature are quite sensitive to the chip width and length. The measured peak at 74 GHz and the calculated peak at 67 GHz have very similar magnitude, i.e. 262 µW (−5.8 dBm) vs 253 µW (−5.9 dBm). The measured peak at 140 GHz and the calculated peak at 145 GHz have magnitude of 53 µW (−12.7 dBm) and 90 µW (−10.4 dBm), i.e. differ by 2.3 dB. The sharp peak calculated at 168 GHz was barely detected in the measurements, which were not performed above 185 GHz as the detected signal reached the minimum level detectable by the TK power meter, whose electrical noise-equivalent power (NEP) equals 5µW/Hz½. Although a peak of water vapour absorption is present near 175 GHz [23,24], as high as 100 dB/km in humid conditions, its influence on the 33 mm propagation path length is negligible. The ohmic losses within the titanium layer may have influenced the power measured at higher frequencies. We investigated numerically the effect of thin (10 to 30 nm) titanium layers under the antenna gold, using the reported value 2.32 x 106 S/m [25] of titanium bulk conductivity; we found that the additional ohmic losses related to the titanium did reduce the calculated peak at 168 GHz in particular, but by less than 10%, which still cannot explain the discrepancy with the measurement at this frequency. It is worth noting that the calculated peak at 168 GHz is related to a fast local variation in the antenna impedance, as can be seen in Fig. 13. At this frequency the antenna impedance real part exhibits a narrow and pronounced dip which makes it closer to the UTC impedance real part; in addition the antenna reactance exhibits a rapid increase which allows the complex-conjugate matching condition to be approached between antenna and UTC. Additionally, we found that both amplitude and position of the calculated peak at 168 GHz are noticeably sensitive to the chip width and length. It is the authors' opinion that this pronounced local variation of the antenna impedance at 168 GHz, responsible for the peak of calculated emitted power, is due to a fortunate combination of effects related to the exact geometrical details of the model and is barely perceivable in the real antenna chip, as is the maximum of measured power around 168 GHz. As a final remark, we note that a slower than estimated transit time limited response, for the UTC integrated with the bow-tie antenna, could account for the measured emitted power being more damped at higher frequencies.
Fig. 15 Comparison between measured radiated power and radiated power calculated within the rectangular solid angle (31.2° x 24.4°) subtended by the 40 x 30 mm2 Thomas Keating window.
Following these considerations and bearing in mind the level of difficulty involved in predicting the absolute power radiated by a system involving so many variables, the agreement between experimental and numerical results shown in Fig. 15 can be deemed very satisfactory. An accurate analysis of the absolute power emitted from an antenna integrated photodetector has not been reported before, including 3D full-wave modelling of photodetector and antenna and taking into account the effect of the actual impedance match/mismatch between photodetector and antenna.
The literature of RF and microwave antenna engineering shows how fundamental the source-to-antenna impedance match is, to maximise the power radiated by antennas. In the more recent context of photonic THz emitters based on antenna integrated photodiodes, this aspect has so far received little attention. An emitter made up of a highly directive and efficient antenna integrated with a high power photodiode, could still be unable to radiated high levels of power if the impedance match between source and antenna is ignored, as most of the power generated by the photodiode could be simply rejected by the antenna. In order to optimise the photodiode-to-antenna coupling efficiency, knowledge of the source (PD) impedance is necessary; with no knowledge of the source impedance the absolute power radiated by an antenna cannot be calculated.
In this paper we have performed for the first time 3D full-wave modelling of a detailed UTC-PD structure, including all epitaxial layers, and calculated the UTC impedance and S11 up to 400 GHz, frequencies not attainable by measuring equipment. This work is indispensable to extend to higher frequencies our previous work on semi-analytical modelling of the UTC impedance, limited to below 110 GHz.
An additional new contribution of this work is that we have provided evidence, for the first time, that proper evaluation of the UTC impedance and UTC-to antenna impedance match can allow accurate calculation of the absolute power radiated by an antenna integrated UTC over the frequency range. We have demonstrated successful prediction of the absolute emitted power by modelling and measuring a 760 µm long bow-tie antenna integrated UTC up to 185 GHz. We have also shown that if the UTC-to-antenna coupling efficiency is modelled based on the classical junction-capacitance/series-resistance concept, calculated and measured radiated power are in substantial disagreement.
The capability of calculating the absolute emitted power correctly raises the possibility to maximise the radiated power via optimisation of UTC-to-antenna impedance match. We can effectively design antennas with ad hoc complex impedance, realising complex-conjugate matching with the UTC.
This work has been supported by the United Kingdom Engineering and Physical Sciences Research Council (EPSRC), grant number: EP/J017671/1.
1. A. Beling, Z. Li, Y. Fu, H. Pan, and J. C. Campbell, "High-power and high-linearity photodiodes," IEEE Photonic Soc. 24th Annu. Meet. PHO 2011 1, 19–20 (2011). [CrossRef]
2. H. Ito, T. Furuta, S. Kodama, and T. Ishibashi, "InP/InGaAs uni-travelling-carrier photodiode with 310 GHz bandwidth," Electron. Lett. 36(21), 1809–1810 (2000). [CrossRef]
3. C. C. Renaud, D. Moodie, M. Robertson, and A. J. Seeds, "High output power at 110 GHz with a waveguide Uni-travelling carrier photodiode," Conf. Proc. - Lasers Electro-Optics Soc. Annu. Meet. 782–783 (2007). [CrossRef]
4. H. Ito, T. Nagatsuma, A. Hirata, T. Minotani, A. Sasaki, Y. Hirota, and T. Ishibashi, "High-power photonic millimetre wave generation at 100 GHz using matching-circuit-integrated uni-travelling-carrier photodiodes," Optoelectron. IEE Proc. 150, 138–142 (2003). [CrossRef]
5. H. Ito, F. Nakajima, T. Furuta, and T. Ishibashi, "Continuous THz-wave generation using antenna-integrated uni-travelling-carrier photodiodes," Semicond. Sci. Technol. 20(7), S191–S198 (2005). [CrossRef]
6. C. Renaud, M. Robertson, D. Rogers, R. Firth, P. Cannard, R. Moore, and A. Seeds, "A high responsivity, broadband waveguide uni-travelling carrier photodiode," Proc. SPIE 6194, 61940C (2006). [CrossRef]
7. H. J. Song, K. Ajito, Y. Muramoto, A. Wakatsuki, T. Nagatsuma, and N. Kukutsu, "Uni-travelling-carrier photodiode module generating 300 GHz power greater than 1 mW," IEEE Microw. Wirel. Compon. Lett. 22(7), 363–365 (2012). [CrossRef]
8. M. Natrella, E. Rouvalis, C.-P. Liu, H. Liu, C. C. Renaud, and A. J. Seeds, "InGaAsP-based uni-travelling carrier photodiode structure grown by solid source molecular beam epitaxy," Opt. Express 20(17), 19279–19288 (2012). [CrossRef] [PubMed]
9. E. Rouvalis, C. C. Renaud, D. G. Moodie, M. J. Robertson, and A. J. Seeds, "Continuous wave terahertz generation from ultra-fast InP-based photodiodes," IEEE Trans. Microw. Theory Tech. 60(3), 509–517 (2012). [CrossRef]
10. H. Eisele, "State of the art and future of electronic sources at terahertz frequencies," Electron. Lett. 46(26), S8–S11 (2010). [CrossRef]
11. C. Mann, "Practical challenges for the commercialisation of terahertz electronics," IEEE MTT-S Int. Microw. Symp. Dig. 2007, 1705–1708 (2007). [CrossRef]
12. A. J. Seeds, M. J. Fice, K. Balakier, M. Natrella, O. Mitrofanov, M. Lamponi, M. Chtioui, F. van Dijk, M. Pepper, G. Aeppli, A. G. Davies, P. Dean, E. Linfield, and C. C. Renaud, "Coherent terahertz photonics," Opt. Express 21(19), 22988–23000 (2013). [CrossRef] [PubMed]
13. M. Natrella, C.-P. Liu, C. Graham, F. van Dijk, H. Liu, C. C. Renaud, and A. J. Seeds, "Accurate equivalent circuit model for millimetre-wave UTC photodiodes," Opt. Express 24(5), 4698–4713 (2016). [CrossRef]
14. E. D. Palik, Handbook of Optical Constants of Solids, Illustrate (Academic, 1998), Vol. 3.
15. T. Pearsall and J. Hirtz, "The carrier mobilities in Ga0.47In0.53As grown by organo-metalic CVD and liquid-phase epitaxy," J. Cryst. Growth 54(1), 127–131 (1981). [CrossRef]
16. A. Katz, B. E. Weir, and W. C. Dautremont-Smith, "Au/Pt/Ti contacts to p-In0.53Ga0.47As and n-InP layers formed by a single metallization common step and rapid thermal processing," J. Appl. Phys. 68(3), 1123–1128 (1990). [CrossRef]
17. G. Reeves and H. Harrison, "Obtaining the specific contact resistance from transmission line model measurements," IEEE Electron. Dev. Lett. 3(5), 111–113 (1982). [CrossRef]
18. H. Berger, "Models for contacts to planar devices," Solid-State Electron. 15(2), 145–158 (1972). [CrossRef]
19. A. Rumiantsev, P. Sakalas, N. Derrier, D. Celi, and M. Schroter, "Influence of probe tip calibration on measurement accuracy of small-signal parameters of advanced BiCMOS HBTs," Bipolar/BiCMOS Circuits Technol. Meet. (BCTM), 2011 IEEE 203–206 (2011).
20. Anritsu, "Understanding VNA Calibration," http://anlage.umd.edu/Anritsu_understanding-vna-calibration.pdf.
21. A. J. Lord, "Comparing the accuracy and repeatability of on-wafer calibration techniques to 110GHz," Microw. Conf. 1999. 29th Eur. 3, 28–31 (1999). [CrossRef]
22. Cascade Microtech Application Note, "On-wafer vector network analyzer calibration and measurements," http://www.cmicro.com/files/ONWAFER.pdf.
23. Y. Yang, A. Shutler, and D. Grischkowsky, "Measurement of the transmission of the atmosphere from 0.2 to 2 THz," Opt. Express 19(9), 8830–8838 (2011). [CrossRef] [PubMed]
24. R. Appleby and H. B. Wallace, "Standoff detection of weapons and contraband in the 100 GHz to 1 THz region," IEEE Trans. Antennas Propagation 55(11), 2944–2956 (2007). [CrossRef]
25. C. Kittel, Introduction to Solid State Physics, 7th ed. (Wiley, 1996).
A. Beling, Z. Li, Y. Fu, H. Pan, and J. C. Campbell, "High-power and high-linearity photodiodes," IEEE Photonic Soc. 24th Annu. Meet. PHO 2011 1, 19–20 (2011).
H. Ito, T. Furuta, S. Kodama, and T. Ishibashi, "InP/InGaAs uni-travelling-carrier photodiode with 310 GHz bandwidth," Electron. Lett. 36(21), 1809–1810 (2000).
C. C. Renaud, D. Moodie, M. Robertson, and A. J. Seeds, "High output power at 110 GHz with a waveguide Uni-travelling carrier photodiode," Conf. Proc. - Lasers Electro-Optics Soc. Annu. Meet. 782–783 (2007).
H. Ito, T. Nagatsuma, A. Hirata, T. Minotani, A. Sasaki, Y. Hirota, and T. Ishibashi, "High-power photonic millimetre wave generation at 100 GHz using matching-circuit-integrated uni-travelling-carrier photodiodes," Optoelectron. IEE Proc. 150, 138–142 (2003).
H. Ito, F. Nakajima, T. Furuta, and T. Ishibashi, "Continuous THz-wave generation using antenna-integrated uni-travelling-carrier photodiodes," Semicond. Sci. Technol. 20(7), S191–S198 (2005).
C. Renaud, M. Robertson, D. Rogers, R. Firth, P. Cannard, R. Moore, and A. Seeds, "A high responsivity, broadband waveguide uni-travelling carrier photodiode," Proc. SPIE 6194, 61940C (2006).
H. J. Song, K. Ajito, Y. Muramoto, A. Wakatsuki, T. Nagatsuma, and N. Kukutsu, "Uni-travelling-carrier photodiode module generating 300 GHz power greater than 1 mW," IEEE Microw. Wirel. Compon. Lett. 22(7), 363–365 (2012).
M. Natrella, E. Rouvalis, C.-P. Liu, H. Liu, C. C. Renaud, and A. J. Seeds, "InGaAsP-based uni-travelling carrier photodiode structure grown by solid source molecular beam epitaxy," Opt. Express 20(17), 19279–19288 (2012).
E. Rouvalis, C. C. Renaud, D. G. Moodie, M. J. Robertson, and A. J. Seeds, "Continuous wave terahertz generation from ultra-fast InP-based photodiodes," IEEE Trans. Microw. Theory Tech. 60(3), 509–517 (2012).
H. Eisele, "State of the art and future of electronic sources at terahertz frequencies," Electron. Lett. 46(26), S8–S11 (2010).
C. Mann, "Practical challenges for the commercialisation of terahertz electronics," IEEE MTT-S Int. Microw. Symp. Dig. 2007, 1705–1708 (2007).
A. J. Seeds, M. J. Fice, K. Balakier, M. Natrella, O. Mitrofanov, M. Lamponi, M. Chtioui, F. van Dijk, M. Pepper, G. Aeppli, A. G. Davies, P. Dean, E. Linfield, and C. C. Renaud, "Coherent terahertz photonics," Opt. Express 21(19), 22988–23000 (2013).
M. Natrella, C.-P. Liu, C. Graham, F. van Dijk, H. Liu, C. C. Renaud, and A. J. Seeds, "Accurate equivalent circuit model for millimetre-wave UTC photodiodes," Opt. Express 24(5), 4698–4713 (2016).
E. D. Palik, Handbook of Optical Constants of Solids, Illustrate (Academic, 1998), Vol. 3.
T. Pearsall and J. Hirtz, "The carrier mobilities in Ga0.47In0.53As grown by organo-metalic CVD and liquid-phase epitaxy," J. Cryst. Growth 54(1), 127–131 (1981).
A. Katz, B. E. Weir, and W. C. Dautremont-Smith, "Au/Pt/Ti contacts to p-In0.53Ga0.47As and n-InP layers formed by a single metallization common step and rapid thermal processing," J. Appl. Phys. 68(3), 1123–1128 (1990).
G. Reeves and H. Harrison, "Obtaining the specific contact resistance from transmission line model measurements," IEEE Electron. Dev. Lett. 3(5), 111–113 (1982).
H. Berger, "Models for contacts to planar devices," Solid-State Electron. 15(2), 145–158 (1972).
A. Rumiantsev, P. Sakalas, N. Derrier, D. Celi, and M. Schroter, "Influence of probe tip calibration on measurement accuracy of small-signal parameters of advanced BiCMOS HBTs," Bipolar/BiCMOS Circuits Technol. Meet. (BCTM), 2011 IEEE 203–206 (2011).
Anritsu, "Understanding VNA Calibration," http://anlage.umd.edu/Anritsu_understanding-vna-calibration.pdf .
A. J. Lord, "Comparing the accuracy and repeatability of on-wafer calibration techniques to 110GHz," Microw. Conf. 1999. 29th Eur. 3, 28–31 (1999).
Cascade Microtech Application Note, "On-wafer vector network analyzer calibration and measurements," http://www.cmicro.com/files/ONWAFER.pdf .
Y. Yang, A. Shutler, and D. Grischkowsky, "Measurement of the transmission of the atmosphere from 0.2 to 2 THz," Opt. Express 19(9), 8830–8838 (2011).
R. Appleby and H. B. Wallace, "Standoff detection of weapons and contraband in the 100 GHz to 1 THz region," IEEE Trans. Antennas Propagation 55(11), 2944–2956 (2007).
C. Kittel, Introduction to Solid State Physics, 7th ed. (Wiley, 1996).
Aeppli, G.
Ajito, K.
Appleby, R.
Balakier, K.
Berger, H.
Cannard, P.
Chtioui, M.
Dautremont-Smith, W. C.
Davies, A. G.
Dean, P.
Eisele, H.
Fice, M. J.
Firth, R.
Furuta, T.
Graham, C.
Grischkowsky, D.
Harrison, H.
Hirtz, J.
Ishibashi, T.
Ito, H.
Katz, A.
Kodama, S.
Kukutsu, N.
Lamponi, M.
Linfield, E.
Liu, C.-P.
Mann, C.
Mitrofanov, O.
Moodie, D. G.
Moore, R.
Muramoto, Y.
Nagatsuma, T.
Nakajima, F.
Natrella, M.
Pearsall, T.
Pepper, M.
Reeves, G.
Renaud, C.
Renaud, C. C.
Robertson, M.
Robertson, M. J.
Rogers, D.
Rouvalis, E.
Seeds, A.
Seeds, A. J.
Shutler, A.
Song, H. J.
van Dijk, F.
Wakatsuki, A.
Wallace, H. B.
Weir, B. E.
IEEE Electron. Dev. Lett. (1)
IEEE Microw. Wirel. Compon. Lett. (1)
IEEE MTT-S Int. Microw. Symp. Dig. (1)
IEEE Trans. Antennas Propagation (1)
IEEE Trans. Microw. Theory Tech. (1)
J. Cryst. Growth (1)
Semicond. Sci. Technol. (1)
Solid-State Electron. (1)
Table 1 Layer structure of the UTCs provided by III-V Lab.
Table 2 Summary of the equivalent circuit optimised parameters.
Table 3 Conductivities used in the full-wave modelling for the layers contributing to the UTC series resistance. The relative electrical permittivity values are also shown, although they play a very marginal role for these layers.
Table 4 Material properties of the two spacers and the collection layer derived by the optimised circuit elements R2, C2, R3, C3, R4 and C4 of Circuit 3. The absorber properties are also shown, although this layer only provides a marginal resistive contribution.
Layer structure of the UTCs provided by III-V Lab.
Doping (cm−3)
Thickness (nm)
p + +
GaInAs
p-contact
p +
Ridge Layer
p-gradual
In0.53Ga0.47As
Spacer layer
n +
n – contact
Fe SI - InP Substrate –
Summary of the equivalent circuit optimised parameters.
R1(Ω)
C2(fF)
Cp(fF)
Lp(pH)
3 x 15 µm2 UTC at 0 V
3 x 15 µm2 UTC at −2 V
(3/4)x 15
(3/4)x 265
4 x 15 µm2 UTC at −2 V (3/4)x 15 (3/4)x 265 (4/3)x 85 (3/4)x 125 (4/3)x 70 3x105 (4/3)x 60 1 16
Conductivities used in the full-wave modelling for the layers contributing to the UTC series resistance. The relative electrical permittivity values are also shown, although they play a very marginal role for these layers.
Layer description
Electrical conductivity (Ω−1m−1)
Relative electrical permittivity
n – contact 600 103000 12.5
Material properties of the two spacers and the collection layer derived by the optimised circuit elements R2, C2, R3, C3, R4 and C4 of Circuit 3. The absorber properties are also shown, although this layer only provides a marginal resistive contribution.
Relative electrical permittivity (0 V bias)
Relative electrical permittivity (−2 V bias)
Spacer Q
Collector 300 0.02 50.45 45.18


I've been watching these blackberries. They have grown nice and plump from all the rain and should be turning dark any day now. Then it will be a race between humans and animals, to see who gets to the ripe ones first. I tend to think in terms of sewing and embellishment, so of course the berries look like clusters of beads to me. I mentally root around in my stash and audition different colors and finishes of seed beads. In order to accurately portray the subtle changes in the colors of the berries, a few more trips to the bead store would be necessary. So I will simply enjoy looking at the ripening blackberries and assign that idea to my ever-growing list, under "Inspired By Nature."


The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the Tenth Public Data Release (DR10) from its current incarnation, SDSS-III. This data release includes the first spectroscopic data from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS) taken through 2012 July. The APOGEE instrument is a near-infrared R similar to 22,500 300 fiber spectrograph covering 1.514-1.696 mu m. The APOGEE survey is studying the chemical abundances and radial velocities of roughly 100,000 red giant star candidates in the bulge, bar, disk, and halo of the Milky Way. DR10 includes 178,397 spectra of 57,454 stars, each typically observed three or more times, from APOGEE. Derived quantities from these spectra (radial velocities, effective temperatures, surface gravities, and metallicities) are also included. DR10 also roughly doubles the number of BOSS spectra over those included in the Ninth Data Release. DR10 includes a total of 1,507,954 BOSS spectra comprising 927,844 galaxy spectra, 182,009 quasar spectra, and 159,327 stellar spectra selected over 6373.2 deg(-2).
Rebull, L. M., D. L. Padgett, C-E. McCabe, L. A. Hillenbrand, K. R. Stapelfeldt, A. Noriega-Crespo, T. Brooke et al. "The Taurus Spitzer Survey: New Candidate Taurus Members Selected Using Sensitive Mid-Infrared Photometry." The Astrophysical Journal Supplement Series, Vol. 186, No. 2 (Apr., 2010): 259.


text:
Decades without daylight: 'West Memphis Three' describe life in prison
the CNN Wire Staff
Updated 7:11 AM EDT, Fri September 30, 2011
Damien Echols, left, and Jason Baldwin spent nearly 20 years in prison for a crime they say they didn't commit.
Editor's Note: "Piers Morgan Tonight" airs at 9 p.m. ET
The three men were released last month after 18 years in prison
They were convicted of the 1993 murder of three boys in West Memphis, Arkansas
No evidence links them directly to the crime
They have always maintained their innocence
The three men spent 18 years behind bars for a brutal crime they said they did not commit. Locked away for life – with one of them sentenced to death – the men thought they would never experience freedom again.
They had been imprisoned for the brutal 1993 murders of three young boys in West Memphis, Arkansas. Evidence against the men was circumstantial, however, and doubts grew over the years about their guilt.
Finally, nearly two decades after the crime, the men were allowed to walk free last month, the result of a complicated plea agreement requiring them to plead guilty even while declaring their innocence.
The men came to be known as the West Memphis Three. Two of them spoke to CNN's Piers Morgan in an interview that aired Thursday – their first sit-down interview since their release.
"I hadn't seen daylight in almost a decade. I hadn't been exposed to sunlight … for almost 10 years," Damien Echols told Morgan about his life on death row, where he lived in isolation in a concrete cell, his food passed to him through a slot in a solid steel door.
"The only thing you can do to maintain your sanity is to not think about the case and not think about what's happening to you," Echols said.
"You have to create your own world in there or you'll go insane from that stuff."
Echols still squints in bright light, the result of living for years in a dimly lit cell. When he left prison and saw daylight for the first time in a decade, Echols said, "it was like having a spotlight turned right in your face. It was extremely bright."
piers.morgan.west.memphis.3_00005429
'West Memphis 3' talk celebrity support
piers west memphis echols_00002602
Damien Echols on conditions in jail
piers memphis three marriage_00002215
Marriage on death row
pmt west memphis 3 bts_00002303
'West Memphis 3' describe new freedom
Echols' friend and co-accused, Jason Baldwin, said he spent the first few years of incarceration being beaten up by fellow inmates, who targeted a man they thought was a child-killer.
He said he suffered a shattered skull and broken collar bone, had teeth knocked out, and was left with scars on his face.
"But as the years progressed and people got to know me, and as the documentaries (about the men's plight) came out and stuff, the curses turned into prayers," Baldwin said. "Those fights turned into hugs."
Baldwin, Echols, and a third man – Jesse Misskelley, who declined to take part in the interview – were imprisoned for the slayings of second-graders Steven Branch, Christopher Byers, and Michael Moore.
The boys' mutilated bodies were left in a ditch, hogtied with their own shoelaces. Prosecutors argued that the defendants – teenagers at the time – were driven by satanic ritual and that Echols had been the ringleader.
Echols and Baldwin said that at the time, they were targeted for being different from the rest of their peers in the small town where they lived. They read different books, wore different clothes, and had different haircuts.
"The evidence against us was our personal preferences in music," Baldwin said. "I remember at one point during the trial, they lifted up a record, a Blue Oyster Cult record, and I think (prosecutor) John Fogleman said this was found in Damien's girlfriend's mother's house."
Critics of the case against the men argued that no direct evidence tied them to the murders, and that a knife recovered from a lake near the home of one of the men could not have caused the boys' wounds.
More recent DNA testing also demonstrated no links, according to the men's supporters, who included actors Johnny Depp and Winona Ryder and singers Eddie Vedder of Pearl Jam and Natalie Maines of the Dixie Chicks.
Echols said their support was "uplifting" and brought attention to their case, ultimately leading to their release.
Now, the men are having to get used to elements of modern life such as computers, the internet, and cell phones, things that most others take for granted. Even ordering a simple cup of coffee is different now.
"At one point, I went to a coffee shop and they were like, what kind of coffee do you want? And I'm like, kind of coffee?" Baldwin said.
The two have been out of prison for a month and a week. Baldwin says he now works for a construction company that's helping him get on his feet again, and he's learning how to drive.
Echols says he hasn't yet found a job but is interested in pursuing visual art. He got married while in prison to Lorri Davis, a woman who took up his cause and started writing him letters in prison.
She said they are still fighting for the real perpetrators to be brought to justice.
"We want to discover who did this," Davis said. "That's the most important thing."
Watch Piers Morgan Live weeknights 9 p.m. ET. For the latest from Piers Morgan click here.


Legacy reports of diplomats are much feared by governments. When Sir Who-he What's-it leaves his last post, the "tell it all" articles and books are not far behind.
There is much less of a tradition of telling successors how it should have been in the "home" public services. So here is a reflection on a decade of Scottish policy and micro-administration during my time at the Association of Scotland's Colleges.
No one can doubt that the colleges are now a sector in their own right alongside schools and universities. The old labels of technical, further and vocational education may still have their uses in education-speak. But if you say "Scotland's Colleges" today, everyone knows what you mean.
I learned just how important identity as a sector can be from a visit to Eire. The Conference of Colleges in Waterford was the first of its kind and included a very different array of sector leaders - not least the vocational education committees (VECs) which oversee colleges and secondary schools for the Department of Education and Science in Dublin.
The lead representative body in Eire is the Irish Vocational Education Association (IVEA) - representing the 33 VECs - rather than an association of the colleges.
It was quite a jolt to find that FE colleges are seen as part of "second level" education (that is, schools), and that the principal qualification is the "post-leaving certificate".
Appointments of staff and establishment of courses have to be approved outside the college - even "infill" of part-time students along with full-timers is controlled. Incorporated governance and academic autonomy on Scottish lines look like mirages.
There are many elements in the expansion and higher status of colleges here - growth in funding for tuition and student support, unitised and devolved course design, cumulative certification, engagement with employers in updating curriculum and occupational requirements and, now, major investment in new or modernised college campuses. But these all depended on first setting colleges free to develop the best provision and service for their communities.
Colleges here take responsibility for developing the new. They don't wait to ask what, when and how to do the next thing students and employers require. Just look at how colleges absorbed the blow of the complete breakdown of SQA certification in 2000-01 and made sure that students caught up in the delays did not lose out.
Ten years ago, I predicted that, by 2000, the watchwords of government would be "stability" and "light touch". How wrong can you be? Colleges are now assailed by wave on wave of new intermediary bodies and micro-prescription. Low-trust, high-cost solutions abound even as ministers talk up "efficient government". Is this just the inevitable consequence of getting a Scottish Parliament intent on using its legislative powers?
It would be great if the Review of Scotland's Colleges - due early this year - reversed this retrograde trend. There will be ample evidence of colleges' ability to move much further towards high-trust, low-cost solutions. They set a standard of reformed public service which others will do well to follow.
Lifelong learning thrives on choice. By opening up access and better opportunities for study and training in colleges, Scotland can unleash the energy and potential of students both for work and their own quality of life.
A standstill in recurrent funding for colleges is here again, at least for 2007-08. But beyond still lies the key challenge of giving more chance and support to those who need lifelong learning most. By all means let's focus on young people not in employment, education or training (Neet) - and above all those leaving care. But Scotland is also off the pace in offering better prospects to the low-paid in work and the hardest-to-reach adults.
Colleges have earned their place as Scotland's comprehensives of lifelong learning. They are not just a bolt-on to schools, or the take-off point for university. More in colleges is definitely better for Scotland.


text:
Login to SpottingHistory.com
Enter your email address and password to log on
Remember my login?
Upload new site
St. Paul's Church
St. Paul's Church, also known as St. Paul's Chapel, is an 1876 Methodist church located in Mariatorget, a square and a city park in Södermalm, central Stockholm. The church was designed by the Swedish architects and brothers Axel and Hjalmar Kumlien.
Religious sites in Sweden
Union with Norway and Modernization (Sweden)
Add New Comment (without Facebook account)
Mariatorget 10, Stockholm, Sweden
See all sites in Stockholm
Category: Religious sites in Sweden
Historical period: Union with Norway and Modernization (Sweden)
4.8/5 (based on Google user reviews)
Interesting Sites Nearby
Storkyrkan (1 km)
Finnish Church (1 km)
Axel Oxenstierna Palace (1 km)
Gamla Stan (0,9 km)
Tessin Palace (1,1 km)
Royal Palace (1,1 km)
German Church (0,9 km)
The Royal Coin Cabinet (1,1 km)
Vasa Museum (2 km)
Drottningholm Palace (10 km)
Vaxholm Church (18,8 km)
St. Olof's Church Ruins (38,6 km)
St. Mary's Church (38,5 km)
Sigtuna Museum (38,3 km)
Vaxholm Castle (19,3 km)
Tyresö Palace (16,5 km)
Dalarö Church (28,5 km)
Österhaninge Church (22,1 km)
The Foreigner (2 years ago)
Emma Thorén (2 years ago)
Talabushi Jensen (2 years ago)
Velena Marhun (4 years ago)
Rea just nu!! Fyndchans!!
Featured Historic Landmarks, Sites & Buildings
Must-See Historic Places in Córdoba
Best of Middle Rhine Valley, Germany
Must-see historic sighs in Luxembourg
Photo from Flickr, copyright Andy Montgomery
Historic Site of the week
Arch of Constantine
The Arch of Constantine is situated between the Colosseum and the Palatine Hill. It was erected by the Roman Senate to commemorate Constantine I's victory over Maxentius at the Battle of Milvian Bridge in 312. Dedicated in 315, it is the largest Roman triumphal arch. The arch spans the Via triumphalis, the way taken by the emperors when they entered the city in triumph.
Though dedicated to Constantine, much of the decorative material incorporated earlier work from the time of the emperors Trajan (98-117), Hadrian (117-138) and Marcus Aurelius (161-180), and is thus a collage. The last of the existing triumphal arches in Rome, it is also the only one to make extensive use of spolia, reusing several major reliefs from 2nd century imperial monuments, which give a striking and famous stylistic contrast to the sculpture newly created for the arch.
The arch is 21 m high, 25.9 m wide and 7.4 m deep. Above the archways is placed the attic, composed of brickwork reveted (faced) with marble. A staircase within the arch is entered from a door at some height from the ground, on the west side, facing the Palatine Hill. The general design with a main part structured by detached columns and an attic with the main inscription above is modelled after the example of the Arch of Septimius Severus on the Roman Forum.
Follow @SpottingHistory
Map Top Sights Tags Historical Periods City Guides About Us Sign Up Upload new site
© 2020 SpottingHistory.com. All rights reserved.
Do you know an ancient castle or magnificent church near you?
Why not share it with other people interested in history? You can add your own historic sites and attractions to SpottingHistory.com.
It's absolutely free, easy, and doesn't even need registration!
Looks like you are a history fan!
Follow us to get best travel tips to interesting historic sites!
Do you know an ancient castle or hidden ruins near you?
Why not share it with other people interested in history? You can add your own historic sites and attractions to SpottingHistory. It's absolutely free, easy, and you can do it even without registration (of course you an also create an free account)!
Yes please, take me to the Upload page


text:
First live stream
Second live stream
Radio Biafra Live
Radiobiafra
Indigenous People of Biafra
Television Biafra
Radio Biafra Forum
Radio Biafra Broadcast
Home Anambra Biafra Featured News Nigeria World News TERRORISTS "IN UNIFORM" ATTACK ORAIFITE, ANAMBRA STATE
TERRORISTS "IN UNIFORM" ATTACK ORAIFITE, ANAMBRA STATE
at 19:40:00 Anambra, Biafra, Featured, News, Nigeria, World News,
It is crystal clear that Nigerian security forces are widely and notoriously known for perpetrating these sorts of uncivilized, unprofessional, barbaric, government ordered assassinations and terrorist acts of shooting peaceful unarmed citizens, raping helpless voiceless women and burning down homes of innocent citizens. The dark history of government ordered extra-judicial killings and burning down whole villages has become a well-known tradition and custom of the Nigerian government. Nigerian police, army and other security services have historically engaged in these terrorist acts at many locations across Nigeria in the recent past. A few examples of these crimes against humanity remain indelible in the memory of every Nigerian.
In the case of Fela Anikulapo Kuti, his house was burnt down and innocent civilians were murdered, including his mother who subsequently died of her injuries sustained in the attack. In the case of Odi in Bayelsa State, the Nigerian army burnt down the entire town, razed it to the ground and massacred the entire population, including their domestic animals and every living thing in sight.
In the genocide at Afaraukwu Ibeku, Abia State, the Nigerian Army gruesomely murdered more than 28 unarmed IPOB members in cold blood at the compound of the IPOB Supreme Leader, Mazi Nnamdi Kanu. In the case of Izzy in Ebonyi State Nigerian security forces murdered more than 250 unarmed men and burnt down their houses. In a recent incident at Aba in Abia State, the Nigerian government uniformed terrorists burnt down 12 buildings and pillaged an entire neighbourhood.
True to type, history has repeated itself in the attempted assassination of IPOB's lawyer, Barrister Ifeanyi Ejiofor, by the joint forces of Nigerian Police, Army and other security services at his country home at Oraifite, Anambra State on 2 December 2019. Eyewitness accounts have given harrowing details of how Nigerian government uniformed assassination squads ferociously shot at guests who were on a condolence visit at Barrister Ejiofor's home, burnt down the residence and other nearby houses with more than 10 occupants in them, shot dead four members of IPOB, shot and injured Barrister Ejiofor's aged mother, and raped women including mothers and young girls. The conduct of Nigerian Security forces at Oraifite amounts to terrorism and crimes against humanity.
Following these atrocities, the Nigerian Police Force issued a press statement alleging that they had acted upon receipt of reliable information and report about alleged assault, kidnap and cult activities at Barrister Ejiofor's premises. Police further alleged that members of IPOB attacked them with weapons at Barrister Ejiofor's premises resulting in the death of two policemen and the burning of a police van.
There is no credibility whatsoever in the claims and allegations put forward by the Nigerian police. The Police press statement failed to address so many questions and issues, including:
(1) Police failed to produce the alleged weapons allegedly used by members of IPOB.
(2) Police failed to name the alleged victims of kidnap nor did police say who allegedly kidnapped the alleged victims.
(3) Police failed to name or identify the alleged cults, and its alleged members said to have engaged in cult activities at Barrister Ejiofor's compound. Police failed to produce any photographic or video evidence of any cult activity it alleged.
(4) Police alleged that two policemen were killed but failed to produce their bodies. Police alleged that two policemen were killed and burnt in the van by members of IPOB, but video evidence shows that four bodies were burnt in the van, which tallies exactly with the number of IPOB members killed by the Police, and whose corpses were loaded into that same van by the police and driven away by the Police. In effect only, the Police could have burnt its own van together with the bodies of the four members of IPOB killed by Police. The police allegations are simply a setup.
(5) Police failed to identify the alleged victims allegedly assaulted by IPOB members or Barrister Ejiofor. Police failed to bring the alleged victims of the alleged assault to press interview or on camera.
(6) Police failed to say or show how or why Barrister Ejiofor's aged mother was shot, nor have police explained how burning down houses, shooting innocent citizens and raping women constitutes the appropriate response to investigation or prosecution of the alleged crimes.
(7) Whereas the Police was at Barrister Ejiofor's home as early as 6 am on the day, the same Police testified that it had received the alleged complaints at 11.30am on the same day, which is five and half hours after it had already attended Barrister Ejiofor's residence supposedly in answer to a complaint that had not yet been made at the time.
The Police statement is simply neither credible nor believable. This matter is one that calls for intervention by the United Nations, European Union, US Government, Amnesty international, non-government organizations, and powerful individuals with conscience to ensure an independent judicial investigation or inquiry directed at unravelling the truth of what happened. On the evidence in the matter to date, the atrocities committed at Oraifite point to a covert Nigerian Government ordered assassination attempt on the life of Barrister Ejiofor, as well as a setup to attempt to implicate and frame IPOB as an armed terrorist organisation which it is not. Barrister Ejiofor and IPOB have to date defeated the Nigerian Government in all court cases in Nigerian Courts. There is another court hearing coming up in January 2020, hence the Nigeria government desperately wants to ensure that Barrister Ejiofor is eliminated by every means possible.
Mazi Nnamdi Kanu had a similar experience, when ahead of his impending court hearing the Nigerian Army attacked his home in Afaraukwu, Abia State in an attempt to assassinate him. 28 members of IPOB and his dog were massacred in that incident. Having failed at their assassination attempt on Barrister Ejiofor, the Nigerian government has reverted to use of the Police to declare him a wanted person. In criminalising Barrister Ejiofor and declaring him a wanted person, the Nigerian Government aims to paralyse Barrister Ejiofor's legal practice, and thereby deny IPOB his competent legal representation in all IPOB matters currently pending before the courts of Nigeria. Concerted investigative journalistic work is currently ongoing in attempt to uncover more details of this covert Nigeria government operation and the individuals behind them.
In Biafra, we trust!
Onumajuru Onyekachi MacSantos & Nwabunwanne David
For: Abia State Media
Lolo Oby Mboma
Chibuike John Nebeokike
Anambra, Biafra, Featured, News, Nigeria, World News
MagPress
NEWS IS VERY IMPORTANT SHARE WITH YOUR FRIENDS...
Powered by The Biafra Telegraph
Order Biafra Telegraph Magazine Now
Buy Biafra Telegrah Magazine Now
Buy Biafra Telegrah Magazine
1st Edition $10.00 USD 2nd Edition $10.00 USD 3rd Edition $10.00 USD 1st, 2nd Edition $20.00 USD 1st, 2nd, 3rd Edition $30.00 USD
Tweets by @BiafraTelegraph
Buhari Continues to violate human Rights Biafrans #FreeNnamdiKanu #FreeBiafra
@EU_Commission #Buhari violates rights of #Biafrans he kidnaps imprisons & murders #FreeNnamdiKanu #FreeBiafra
As genocide looms in Nigeria, IPOB restates call for referendum
— Nigeria: A History Of Serial Genocide And The Urgent Need For A Referendum On Biafra — Being a Presentation by the Indigenous...
PULL DOWN ALL MOSQUES IN BIAFRA.
B IA FR A Why is all generations that fought and saw Biafran war with Nigeria 1967-1970 hesitant in doing the needful about their sec...
Kerry Meets Buhari in Aso Rock, Urged him to Release Nnamdi Kanu and Let Biafrans Go
The US secretary of state John Kerry visited Nigeria amid heavy economic and political crisis, his visit proves problematic for Buhari in...
BREAKING NEWS!!! Nigeria Senators Fought Over BIAFRA Issue.
A senator from the north suggested that islamic state should be given to boko harram to stop the killigs, Senator ike ekweremadu s...
The Murdering of Mrs Bridget over Blasphemy, how it Happened
B I A F R A Angry Muslims youths in Kano on Thursday evening decapitated a woman trader (Mrs. Bridget Agbahime) over allegations that ...
Africa Anambra Biafra Culture ECOWAS Featured Gallery Igbo Igweocha IPOB News Niger Delta Nigeria Nnamdi Kanu Opinions Politics Referendum Sport Video World News
Blog Archive January (14) December (47) November (37) October (80) September (46) August (55) July (38) June (66) May (52) April (51) March (44) February (76) January (90) December (85) November (72) October (84) September (77) August (66) July (50) June (58) May (101) April (68) March (83) February (85) January (43) December (39) November (81) October (118) September (133) August (139) July (115) June (124) May (116) April (115) March (135) February (126) January (106) December (87) November (96) October (173) September (231) August (244) July (194) June (204) May (215) April (177) March (209) February (93)
Subscribe Newsletter and FOLLOW BY EMAIL
The Biafra Telegraph © 2017-2018. All Rights Reserved.


text:
Get On Such a Full Sea from Amazon.com
Order our On Such a Full Sea Study Guide
On Such a Full Sea - Chapters 10-12 Summary & Analysis
Chang-Rae Lee
This Study Guide consists of approximately 52 pages of chapter summaries, quotes, character analysis, themes, and more - everything you need to sharpen your knowledge of On Such a Full Sea.
Chapter 10 discusses Quig's life before living in the compound. He had a normal Charter life, and was educated in veterinarian medicine. He married a woman named Glynnis, and they had a daughter named Trish. Pets were highly regarded in the Charters and Quig made a great living until an outbreak of a hemorrhagic fever crossed from animals to humans. Domestic animals were put down and Quig lost his practice. Quig and Glynnis took other jobs to try and make ends meet. Eventually, Glynnis started selling the leftover veterinary drugs on the black market. They were caught, tried, and convicted, which resulted in their banishment from the charter. This was all the information Penelope gave Fan. Quig and Fan talk while they're in the car while Loreen's sleeps. Quig asks Fan if she wants to drive for real this time. Fan...
(read more from the Chapters 10-12 Summary)
More summaries and resources for teaching or studying On Such a Full Sea.
On Such a Full Sea from BookRags. (c)2020 BookRags, Inc. All rights reserved.


text:
Q: Understanding how to calculate removal effects in a markov chain I am currently trying to model a Marketing Multi-Channel Attribution. All the articles and the packages I have come across use a special "start" state and the removal effect is calculated based on that start state using the following matrix operations given here ([Markov chain in Python])[1].
def removal_effects(df, conversion_rate):
removal_effects_dict = {}
channels = [channel for channel in df.columns if channel not in ['Start',
                                                                 'Null',
                                                                 'Conversion']]
for channel in channels:
    removal_df = df.drop(channel, axis=1).drop(channel, axis=0)
    for column in removal_df.columns:
        row_sum = np.sum(list(removal_df.loc[column]))
        null_pct = float(1) - row_sum
        if null_pct != 0:
            removal_df.loc[column]['Null'] = null_pct
        removal_df.loc['Null']['Null'] = 1.0

    removal_to_conv = removal_df[
        ['Null', 'Conversion']].drop(['Null', 'Conversion'], axis=0)
    removal_to_non_conv = removal_df.drop(
        ['Null', 'Conversion'], axis=1).drop(['Null', 'Conversion'], axis=0)

    removal_inv_diff = np.linalg.inv(
        np.identity(
            len(removal_to_non_conv.columns)) - np.asarray(removal_to_non_conv))
    removal_dot_prod = np.dot(removal_inv_diff, np.asarray(removal_to_conv))
    removal_cvr = pd.DataFrame(removal_dot_prod,
                               index=removal_to_conv.index)[[1]].loc['Start'].values[0]
    removal_effect = 1 - removal_cvr / conversion_rate
    removal_effects_dict[channel] = removal_effect

return removal_effects_dict

My question primarily is of two parts:

*

*Can we consider the first touch as the start state of each path.

*How can we calculate the removal effect if there is no start state( any documentation or an explanation of the formula would be really helpful)

My references :
https://gist.github.com/MortenHegewald/fb1d8051cd818c25283cbcbc4b587e5c#file-removal_effects-py
www.analyzecore.com/2016/08/03/attribution-model-r-part-1/

redpajama_set_name: RedPajamaStackExchange


text:
Marion Public Health: Restaurant Inspections, Oct. 19-24
The following restaurant inspections with critical violations were conducted by Marion Public Health between Oct. 19 and 24.
Marion Public Health: Restaurant Inspections, Oct. 19-24 The following restaurant inspections with critical violations were conducted by Marion Public Health between Oct. 19 and 24. Check out this story on marionstar.com: https://www.marionstar.com/story/news/local/2018/10/25/marion-public-health-restaurant-inspections-oct-19-24/1759847002/
Restaurant inspections.(Photo: . / Stock art)
MARION - The following restaurant inspections with critical violations were conducted by Marion Public Health between Oct. 19 and 24.
Cooper's Bowl, 191 Barks Road W., Marion, Oct. 19. Food equipment surfaces not cleaned at required frequency (critical, corrected during inspection).
G & R Tavern, 103 S. Marion St., Waldo, Oct. 24. Handwashing sink is being used for purposes other than handwashing (critical, corrected during inspection).
Belly Busters Pizzeria, 123 E. Main St., Waldo, Oct. 24. Equipment food-contact surfaces or utensils are unclean (critical, corrected during inspection). Refrigerated, ready-to-eat, TCS foods not properly date marked (critical, corrected during inspection).
Marca Industries Inc., 2465 Harding Highway East, Marion, Oct. 24. Equipment food-contact surfaces or utensils are unclean (critical, corrected during inspection).
For full restaurant inspection details, visit https://healthspace.com/clients/ohio/marion/web.nsf.
Read or Share this story: https://www.marionstar.com/story/news/local/2018/10/25/marion-public-health-restaurant-inspections-oct-19-24/1759847002/


text:
Q: Proof of reflexive, symmetric and transitive when m | n I'm trying to write proofs or counterexample using the definition of divides only for each operation (reflexive, symmetric or transitive) in the following:
The relation V on Z+ for all m and n in Z+, mVn <-> m | n.
I'm familiar with the set operations as:
V is reflexive if for all x in A, xVx.
V is symmetric if for all x, y in A, if xVy, then yVx.
V is transitive if for all x, y and z in A, if xVy and yVz, then xVz.
I'm just not sure how to approach divisibility her. Any help would be appreciated!

A: You have reflexive property because every positive integer divides  itself.
You do not have  symmetry because for example $5|10$ but $10\not | 5$
You do have transitive property because if $x|y$ and $y|z$ then $x|z$
You can fill in the details of the proof for each part.
This relation is not an equivalence relation.