What is ultraviolet light Ultraviolet light is divided into four bands according to wavelength: 1 UVA band, wavelength 320 ~ 420nm, also known as long-wave black spot effect ultraviolet light. It has a strong penetrating power and can penetrate most transparent glass and plastic. More than 98% of the long-wave ultraviolet rays contained in sunlight can penetrate the ozone layer and clouds to reach the surface of the earth. UVA can directly reach the dermis layer of the skin, destroying elastic fibers and collagen fibers, and tanding our skin. UVA ultraviolet light at a wavelength of 360 nm conforms to the phototaxis reaction curve of insects, and can produce a light trap. UV-AUV at a wavelength of 300-420 nm can pass through a special colored glass tube that completely cuts off visible light, and emits only near-ultraviolet light centered at 365 nm. It can be used in ore identification, stage decoration, banknote verification and other places. Use of UV equipment The sample to be tested is irradiated with ultraviolet rays, and certain substances of the sample, such as proteins and nucleic acids, are excited to emit fluorescence, and the detected fluorescence is detected to determine the content of certain substances in the sample. This principle can be used in many fields. 1 Tested in scientific experiments, many major substances such as proteins, nucleotides, etc. UV equipment selection 1 Photometric accuracy Photometric accuracy refers to the difference between the actual measured photometric reading and the true value. It is a direct user requirement for the instrument, and every user must pay attention to it. UV damage to the human body Electromagnetic waves with a wavelength of 100-400 nm are called ultraviolet rays, which are one of the invisible parts of the spectrum, and the sun is a very strong source of ultraviolet light. The right amount of ultraviolet light is good for human health, but exposure to excessive amounts of ultraviolet light can be harmful to human function. In a production environment, when the temperature of an object exceeds 1200 degrees, ultraviolet rays can appear in the radiation spectrum. Electric welding, gas welding, steel making, etc., and who use arc lamps, mercury lamps, flash lamps, ultraviolet disinfection lamps, etc. can receive ultraviolet radiation. Safeguard: 1 Increase the distance from the source. Chilli pepper Laiwu Manhing Vegetables Fruits Corporation , https://www.manhingfood.com
2 UVB band, wavelength 275 ~ 320nm, also known as medium wave erythema effect ultraviolet light. Medium penetration, its shorter wavelength is absorbed by transparent glass, and most of the medium-wave ultraviolet rays contained in sunlight are absorbed by the ozone layer, and less than 2% can reach the surface of the earth, which is particularly strong in summer and afternoon. UVB UV has an erythema effect on the human body, which can promote mineral metabolism and vitamin D formation in the body, but long-term or excessive exposure will cause the skin to tan, and cause redness and peeling. Ultraviolet health lamps and plant growth lamps are made using special transparent purple glass (without light below 254 nm) and phosphors with peaks around 300 nm.
3 UVC band, wavelength 200 ~ 275nm, also known as short-wave sterilization UV. It has the weakest penetration and cannot penetrate most of the transparent glass and plastic. The short-wave ultraviolet rays contained in sunlight are almost completely absorbed by the ozone layer. Short-wave ultraviolet rays are very harmful to the human body. Short-term exposure can burn the skin, and long-term or high-intensity exposure can also cause skin cancer. Ultraviolet germicidal lamps emit UVC short-wave ultraviolet rays.
4 UVD band, wavelength 100 ~ 200nm, also known as vacuum ultraviolet.
2 In drug production and research, it can be used to check hormone alkaloids, vitamins and other energy; produce fluorescent drug quality, especially suitable for thin layer analysis and paper layer analysis spots and detection.
3 In the chemical industry such as dye coating rubber and petroleum, various fluorescent materials, fluorescent indicators and additives are determined to identify different types of crude oil and rubber products.
4 Different types of raw materials can be determined in textile chemical fibers. Such as wool, silk rayon, cotton, synthetic fiber, and can check the quality of the finished product.
5 In the grain, oil, vegetable, food sector, can be used to check the quality of toxins (such as aflatoxin, etc.), food additives, degraded vegetables, fruits, cocoa beans, chocolate, fat, honey, sugar eggs, etc.
6 In the departments of geology and archaeology, it is possible to discover various minerals and distinguish the authenticity of cultural fossils.
7 The public security department can check fingerprints and measure secret writing.
2 stray light It means that there should be light where there should be no light. It is the main source of error in spectral measurements. Of course, the smaller the value, the better.
3 Spectral bandwidth refers to the band width at the 1/2 height of the monochromatic spectral line intensity profile from the monochromator. Characterize the spectral resolution of the instrument. According to Beer's law, the spectral bandwidth should be as small as possible, but if the source energy of the instrument is weak, the sensitivity of the optical sensor is low, the spectral bandwidth is small, and the ideal measurement result is not obtained. Therefore, be careful when selecting and using the instrument.
4 Stability stability is one of the most important indicators for users. The purpose of the instrument is to be stable and reliable, and unstable is not reliable.
5 Noise noise is also one of the important indicators of the instrument. It characterizes the instrument's ability to make dilute solutions. This indicator is also as small as possible.
6 Wavelength Accuracy and Reproducibility Each value of the instrument is measured at a certain wavelength. If the wavelength shown and the actual wavelength deviate by a million miles, then what is the agreement between the measured value and the true value? What? The importance of this indicator can be seen.
These indicators are independent and interrelated, and each indicator has a great impact on the use of the instrument.
The shorter the wavelength of ultraviolet light, the greater the damage to human skin. When the ultraviolet rays illuminate the skin, it can cause blood vessels to dilate. Excessive irradiation can produce diffuse erythema and form small blisters and edema. Long-term exposure can make the skin dry and aging lose its elasticity. When applied to the eye, it can cause acute cornea and may also induce cataract. When it acts on the central nervous system, symptoms such as headache, dizziness, and elevated body temperature may occur.
2 Workers such as electric welding must wear protective masks, gloves, and no exposed skin.