1. Electromagnetics

Magnetic resonance tomography is a multi-parameter, multi-core imaging technology. At present, the main imaging is the density relaxation time T and T of hydrogen nuclei (H). The basic principle is to use electromagnetic waves of a certain frequency to irradiate the human body in a magnetic field. Under the action of electromagnetic waves, the hydrogen nuclei of various tissues in the human body will Nuclear magnetic resonance occurs and absorbs the energy of electromagnetic waves.

Then the electromagnetic waves are emitted. After the MRI system detects the electromagnetic wave signals emitted from the hydrogen nuclei in the human body, the tomographic image of the human body is obtained through computer processing and image reconstruction. Since hydrogen nuclei are affected by the surrounding chemical environment when absorbing and emitting electromagnetic waves, the tomographic images of the human body obtained from magnetic resonance signals can reflect morphological information.

2. Ultrasound

Ultrasound is used for diagnosis and treatment in medicine, thus forming ultrasonic medicine. Ultrasound is widely used in clinical diagnosis. It mainly uses the good directivity of ultrasound and the physical laws of reflection, scattering, attenuation and Doppler effect similar to those of optics. It uses an ultrasonic generator to emit ultrasonic waves into the body and spread them in the tissues. spread within.

3. Mercury thermometer

Mercury thermometer is a type of expansion thermometer. The freezing point of mercury is -38.87℃ and the boiling point is 356.7℃. It is used to measure 0--150℃ or For temperatures within the range of 500°C, it can only be used as an instrument for local supervision. Using it to measure temperature is not only simple and intuitive, but also can avoid the error of external remote thermometer.

4. Oxygen cylinder

Oxygen cylinder is a high-pressure container used to store and transport oxygen. It is generally made of hot-stamped and pressed alloy structural steel and has a cylindrical shape. Used in hospitals, first aid stations and nursing homes.

The oxygen tank relies on the principle of using high pressure (usually 15 MPa) to turn oxygen into liquid oxygen and store it in the tank.

5. Germicidal lamp

It is actually a low-pressure mercury lamp. Low-pressure mercury lamps use low mercury vapor pressure (<10-2Pa) to be excited to emit ultraviolet light. There are two main spectral lines: one is 253.7nm wavelength; the other is 185nm wavelength, both of which are visible to the naked eye. Invisible UV rays.

Because cells have a pattern in the absorption spectrum of light waves. Ultraviolet rays between 250 and 270nm have the maximum absorption. The absorbed ultraviolet rays actually act on the genetic material of the cells, namely DNA. The energy of ultraviolet photons is absorbed by the DNA. The base pairs in the bacteria are absorbed, causing the genetic material to mutate, causing the bacteria to die immediately or be unable to reproduce, achieving the purpose of sterilization.