The sun in the sky is like a fire. The question of "choosing a sunglasses that suits you" has already been thought of in everyone's mind... But how do you choose sunglasses correctly? I believe that everyone has seen low-cost, quality-assured sunglasses on the roadside or in small shops. They look beautiful. They look good in texture and texture, so many people will be happy to buy them. As everyone knows, sunglasses without quality assurance will be very harmful to the glasses. Some sunglasses can not only do not even the most basic UV protection, but also absorb more ultraviolet rays, causing serious eye injuries and even blindness. The inspectors of Zhejiang Jiaxing Inspection and Quarantine Bureau introduced the relevant knowledge of sunglasses selection, hoping to improve everyone's awareness of eye protection: Judging the pros and cons of sunglasses can start with quality and aesthetics. Aesthetics have personal factors, and quality has certain standards. The quality of sunglasses mainly refers to the quality of the lens. The current standard in the world is the US Food and Drug Administration (FDA) standard. According to the FDA standard, the lens should filter out more than 90% of the ultraviolet rays in the sunlight while protecting the light transmittance. The lens should be labeled “UV-100PROTCT10Nâ€. When 100% of the UV filter is removed, the label “UV-400PROTCT10N†should be attached. . Therefore, it is important to look at the UV labels on the lenses. The lens cannot have the "degree" of the optical lens. Generally, if the diopter exceeds 15%, it will feel dizzy when worn. The lens must have a high strength and pass the impact test. In general, the strength of plastic sheets (propionic acid or cellulose acetate), resin sheets and glass sheets is as small as possible. As for which color to choose, the color of the sunglasses should be selected according to the skin color, face shape, and wear. In general, the black, brown, and gray filters work well. The gray lens can absorb evenly in any chromatogram. The scene seen after wearing the mirror will only be darkened without obvious color difference; the brown lens can filter out a large amount of blue light, which can improve the visual contrast and sharpness, and the air pollution is serious or It is especially good to wear in foggy situations. (Xu Jie)
Ethylene amines refers to the acyclic ethylenediamine polymer products, as an important fine chemical intermediates, ethylene amines in organic synthesis, medicine, dye, pesticide, chemical fertilizer, rubber plastic additives, organic solvents and Epoxy Resin Curing Agent, and other fields has been widely used. which become to be one of the fine petrochemical intermediates for the development of China. Ethylenediamine (EDA) is a very important intermediate, mainly used to produce EDTA(chelating agent) and TAEDA(bleach activator), can also be used to produce Organic Dye, Dye-fixing Agent, coating, pesticide, etc. Piperazine can be used to produce anhydrous piperazine, n-methyl piperazine, n-ethyl piperazine, pharmaceutical intermediates, fluperacid, halogen free flame retardant, triethylene diamine. Piperazine has been exported to India and Japan.
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