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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
|Mercedes-Benz instantly {picked up|acquired|found|grabbed} a whole lot of recognition {for this|with this|because of this|just for this} model {when it|if this|in the event it|if it} {was first|was initially|was} presented {at the|in the|on the|with the} 2009 Frankfurt Auto Show in Germany. Although it {is not|isn't|just isn't|is just not} officially {out on|on|from} {the street|the road|the trail|the path} yet, {it is|it's|it really is|it can be} already {the safety|the security|the protection} automobile {for the|for that|for your|to the} Formula One Championship series, {and it's also|also it's|plus its|in fact it is} already featured {in the|within the|inside the|inside} PS 3 videogame Gran Turismo 5.
This is the reason why the condition in your aquarium, especially your reef tank, must be kept as stable as possible at all times. Even the slightest variations might stress your creatures excessive, which enable it to result in outbreaks in diseases or fatality, on account of there ability to handle parasitic attacks.Marine life forms usually are not as resilient his or her freshwater counterparts, especially stress from being brought home in a plastic bag, during shipping in containers while being transported, via one environment to a different one due to water alterations in different tanks. there are numerous other scenarios also.
Space probe according to the detection of object is divided into lunar probe, probe and interplanetary spacecraft, small body such as a space probe to leave the speed of the earth must be large enough to overcome or get rid of the earth's gravity, realize the deep space flight. The probe orbits the heliocentric elliptical orbit (double-cut orbit) that is tangent to the earth's orbit and the planet's orbit, and may meet the target planet; Increase speed to change the orbit, flew to target the planet can shorten the time in order to ensure the detector fly the double track to the planetary orbits and tangent with the target when the target planets also run to it, must be chosen in the earth and the target planet at a particular moment of relative position detector. Detector can fly around the star, the use of planetary gravitational fields accelerate continuous multiple planets orbit the significant characteristic of space probe is, flying in space for long time, the ground cannot real-time remote control, so must have the ability of autonomous navigation; To fly outside the solar system, away from the sun, solar arrays, and nuclear energy systems; It is necessary to adopt special protective structure to withstand very severe space environment. Landing or walking on the surface of the moon or planet requires some special form of structure
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