Atomic clock. An atomic clock is a clock device that uses an electron transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element. Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS. The principle of
From Wikipedia, the free encyclopedia. Wound healing is the process by which skin or other body tissue repairs itself after trauma. In undamaged skin, the epidermis (surface layer) and dermis (deeper layer) form a protective barrier against the external environment.
One method the body uses to heal itself is by scarring. This generally occurs with injuries that penetrate the skin and/or muscle tissue. First, your white blood cells knit together to form a clot that stops the blood from leaving your body. Then, a protein called collagen forms at the site of the injury to repair the damage. In fact, this is the same type of tissue that was there originally, but the difference is in the way it forms.