天天博客

还是今天，整理照片时，发现一张很奇怪的片子，当时是在阳台上拍的，拍了很多张，只有这张是这样，有可能是玄光吧，那也太奇怪了。

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整理相机，发现一些前一段拍的照片，贴上来.

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it is important to consider a number of factors when selecting an air filtration system.care should be taked that the system will serve the long range needs of the building, since it is sometimes quite difficult to justify changes after the system is installed.

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HEPA (High Efficiency Particulate Air) filters are the highest efficiency air filters available for the filtration of small particles. Defined by the Institute of Environmental Science, a Certified HEPA filter must capture a minimum of 99.97% of contaminants at 0.3 microns in size.

The first HEPA filters were developed in the 1940’s by the USA Atomic Energy Commission to full-fill a top-secret need for an efficient, effective way to filter radioactive particulate contaminants. They were needed as part of the Manhattan Project, which was the development of the atomic bomb. The first HEPA air filters were very bulky compared to the HEPA air filters that are produced today. HEPA filter technology was declassified after World War 2 and then allowed for commercial and residential use.

HEPA air filters have been traditionally used in hospital operating and isolation rooms, pharmaceutical and computer chip manufacturing, as well as in other applications requiring “Absolute” Filtration. Today HEPA air cleaners, vacuum cleaners and air filters are used in a wide variety of critical filtration applications in the nuclear, electronic, aerospace, pharmaceutical and medical fields. HEPA air cleaners, vacuum cleaners and air filters are required by law to be used in all equipment for asbestos, lead, toxic chemical and mold abatement. These HEPA filtered products must meet the strict Military Standard 282 HEPA filtration efficiency test.