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The rapid development of air filters is closely related to the development of military industry and electronic industry. In the first world war, the use of various chemical agents, asbestos fibre filter paper as the smoke filter layer of military gas masks came into being. The glass fiber filter medium is used in air filtration to obtain a patent in the United States in October 1940. In the 1950s, the United States studied the production process of glass fiber filter paper, and the air filter was improved and developed. In the 1960s, HEPA filters came out; In the 1970s, the filter paper of fine glass fiber was used as the HEPA filter of filter medium, and the filtration efficiency of particle size of 013 micron particle diameter was 99.9998%. Since the eighty s, with the emergence of new test method, use evaluation to improve and to improve the filtering performance requirements, found the HEPA filter there is a serious problem, and he had a higher ULPA filter performance. Countries are still working on it and expect more advanced air filters soon
Besides to be able to unleash your inner want to run free and wildly, you may also sharpen your abilities in driving. Such game like the F1 car racing, by way of example, enables you to go through the racing tracks and compete against other racers. Again, it's not necessary to be worried about your individual safety kinds. Even if you crash you ride or you flip over and over again, that you do not put yourself in the line or jeopardy. The most general benefits you may get from playing this sort of game are:
1. All checkpoints on the state road of the province shall be revoked from the date of the month of the month, unless the necessary checkpoints shall be set up in the highway traffic highway bordering the province and the adjacent province (district).
New Car Buying Tips--
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