in epidemiology a group of individuals who share a characteristic acquired at the same time. The term usually refers to a birth cohort, which contains animals born in a specified time period. cohort studies. a prospective or follow-up, analytical, epidemiological study.n epidemiology a group of individuals who share a characteristic acquired at the same time. The term usually refers to a birth cohort, which contains animals born in a specified time period. cohort studies. a prospective or follow-up, analytical, epidemiological study.
From Wikipedia, the free encyclopedia. Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. It is a precursor to almost all fluorine compounds, including pharmaceuticals such as fluoxetine (Prozac), diverse materials such as PTFE (Teflon), and elemental fluorine itself.
High Frequency (HF) or Radio Frequency (RF) welding is the joining of materials by supplying HF energy in the form of an electromagnetic field (27.12 MHz) and pressure to the material surfaces to be joined. A generator produces the energy. The tool used to supply the energy is called an electrode.