1, electromagnetism
Magnetic *** vibration tomography is - a multi-parameter, multi-nuclear species of imaging technology. At present, the main hydrogen nucleus ( H) density relaxation time T, T imaging, the basic principle is to use a certain frequency of electromagnetic waves to the human body in the magnetic field irradiation, the human body in a variety of different tissues of the hydrogen nucleus in the role of electromagnetic waves, will occur in the nuclear magnetic **** vibration, absorption of the energy of electromagnetic waves.
After the electromagnetic wave is emitted, the MRI system detects these electromagnetic signals emitted by the hydrogen nuclei from the human body, and then the computer processes and reconstructs the image to obtain a tomographic image of the human body. Because the hydrogen nucleus absorbs and emits electromagnetic waves, affected by the surrounding chemical environment, so the tomographic image of the human body obtained by the magnetic **** vibration signal, can reflect the morphological information.
2, ultrasound
Ultrasound is used in medicine for diagnosis and treatment, resulting in the formation of ultrasound medicine. Ultrasound is widely used in clinical diagnosis, it is mainly the use of ultrasound good directionality and similar to the optical reflection, scattering, attenuation and the Doppler effect and other physical laws, the use of ultrasound generators to transmit ultrasound waves into the body, and propagation in the tissue.
3, mercury thermometer
Mercury thermometer is a kind of expansion thermometer, the freezing point of mercury is -38.87 ℃, boiling point is 356.7 ℃, used to measure the temperature within the range of 0 - 150 ℃ or 500 ℃, it can only be used as a local supervision of the instrument. Using it to measure temperature is not only simpler and more intuitive, but also avoids the errors of external remote thermometers.
4, oxygen cylinders
Oxygen cylinders are high-pressure containers for storing and transporting oxygen, generally made of alloy structural steel hot-punching, pressing, cylindrical. Used in hospitals, first aid stations, nursing homes.
Oxygen tanks rely on the principle of the use of high pressure (generally 15 MPa), so that oxygen into liquid oxygen, stored in the tank.
5, germicidal lamp
Actually belongs to a low-pressure mercury lamp. Low-pressure mercury lamp is the use of lower mercury vapor pressure (<10-2Pa) is excited to send out ultraviolet light, its hair line has two main: one is 253.7nm wavelength; another is 185nm wavelength, these two are invisible to the naked eye ultraviolet light.
Because the cellular absorption spectrum of light waves has a law, in 250 ~ 270nm of ultraviolet light has the largest absorption, the absorbed ultraviolet light is actually acting on the cellular genetic material that is DNA, ultraviolet photon energy is absorbed by the DNA in the base pairs, causing genetic material to mutate, so that the bacteria immediately die or can not reproduce offspring, to achieve the purpose of sterilization.