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结合实际论述艺术鉴赏的基本过程和市美效应。
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Electric Backpack Backpacks are convenient. They can hold your books, your lunch, and a change of clothes leaving your hands free to do other things. Someday, if you don’t mind carrying a heavy load, your backpacks might also power your MP3 player, keep your cell phone running, and maybe even light your way home. Lawrence C. Rome and his colleagues from the University of Pennsylvania in Philadelphia and the Marine Biological Laboratory in WoodsHole, Mass. have invented a backpack that makes electricity from energy produced while its wearer walks. In military actions search-and-rescue operations and scientific field studies, people rely increasingly on cell phones global positioning system (GPS) receivers, night-vision goggles, and other battery powered devices to get around and do their work. The backpack’s electricity-generating feature could dramatically reduce the amount of a wearer’s load now devoted to spare batteries, report Rome and his colleagues in the Sept.9 science. The backpack’s electricity-creating powers depend on springs used to hang a cloth pack from its metal frame. The frame sits against the wearer’s back, and the whole pack moves up and down as the person walks. A gear mechanism converts vertical movements of the pack to rotary motions of an electrical generator, producing up to 7.4 watts. Unexpectedly, tests showed that wearers of the new backpack alter their gaits in response to the pack’s oscillations, so that they carry loads more comfortably and with less effort than they do ordinary backpacks. Because of that surprising advantage, Rome plans to commercialize both electric and non-electric versions of the backpack. The backpack could be especially useful for soldiers, scientists, mountaineers, and emergency workers who typically carry heavy backpacks. For the rest of us, power-generating backpacks could make it possible to walk, play video games, watch TV, and listen to music, all at the same time. Electricity-generating packs aren’t on the market yet, but if you do get one eventually just make sure to look both ways before crossing the street! The word "springs" in Paragraph 3 means ______.
患者，女，45岁，经常头痛，头晕10年，加重2d，伴有恶心呕吐送急诊，检查：神志模糊，BP230/120mmHg，尿蛋白(++)，尿糖(+)。 若诊断成立，其发病机制是
患者，女，28岁，因心悸，气急，胸闷半个月入院。病前2周曾有发热，腹泻史。体检：肺部无啰音，心界向左明显扩大，HR108/ min，律齐，第一心音减低，心尖可闻及2/6级收缩期杂音，ESR 40mm/h，抗“O”阴性，CK360U，心电图示窦性心动过速，一度房室传导阻滞，心肌损害。本病例可初步诊断为
The Issue of Package Maybe everyone has such an experience that you have to unwrap several layers of packaging when you enjoy a piece of candy. But this overuse of wrapping is not confined to luxuries. It is becoming increasingly difficult to buy anything that is not done up in beautiful wrapping. The package itself is of no interest to the shopper, who usually throws it away immediately. So why is it done Some of it, like the cellophane on meat, is necessary, but most of the rest is simply competitive selling. This is absurd. Packaging is using up scarce energy and resources and messing up the environment. Recycling is already happening with milk bottles which are returned to the dairies, washed out, and refilled. But both glass and paper are being threatened by the growing use of plastic. More dairies are experimenting with plastic bottles. The trouble with plastic is that it does not rot. Some environmentalists argue that the only solution to the problem of ever increasing plastic containers is to do away with plastic altogether in the shops, a suggestion unacceptable to many manufacturers who say there is no alternative to their handy plastic packs. It is evident that more research is needed into the recovery and reuse of various materials and into the cost of collecting and recycling containers as opposed to producing new ones. Unnecessary packaging, intended to be used just once, and make things look better so more people will buy them, is clearly becoming increasingly absurd. But it is not so much a question of doing away with packaging as using it sensibly. What is needed now is a more advanced approach to using scarce resources for what is, after all, a relatively unimportant function. Packaging is important to manufacturers because ______.
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