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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! Backpacks are convenient because ______.
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The Case of the Disappearing Fingerprints One useful anti-cancer drug can effectively erase the whorls and other characteristic marks that give people their distinctive fingerprints. Losing (51) become troublesome. A case released online in a letter by Annals of Oncology indicates how big a (52) of losing fingerprints is. Eng-Huat Tan, a Singapore-based medical doctor describes a 62-year old man who has used capecitabine to (53) his nasopharyngeal cancer. After three years on the (54) , the patient decided to visit U.S. relatives last December. But he was stopped by U.S customs officials (55) 4 hours after entering the country when those officials couldn’t get fingerprints from the man. There were no distinctive swirly (56) appearing from his index finger. U.S. customs has been fingerprinting incoming foreign visitors for years, Tan says. Their index fingers are (57) and screened against digital files of the fingerprints of bad guys—terrorists and potential criminals that our federal guardians have been tasked with keeping out of the country. Unfortunately, for the Singapore travelers, one potential (58) effect of his drug treatment is a smoothing of the tissue on the finger pads. (59) , no fingerprints. "It is uncertain when fingerprint loss will (60) to take place in patients who are taking capecitabine," Tan points out. So he cautions any physicians who (61) the drug to provide their patients with a doctor’s note pointing out that their medicine may cause fingerprints to disappear. Eventually, the Singapore traveler made it into the United States. I guess the name on his passport didn’t raise any red flags. But he’s also now got the explanatory doctor’s note-and won’t leave home (62) it. By the way, maybe the Food and Drug Administration, (63) approved use of the drug years ago, should consider (64) its list of side effects associated with this medicine. The current list does note that patients may experience vomiting, stomach pain and some other side effects. But no where (65) it mention the potential for loss of fingerprints.
自2008年11月1日起，对个人首次购买90平方米及以下普通住房，契税税率统一为3%。 ( )
[A] stars[B] bridge[C] knife[D] card[E] ears[F] boat[G] park You’ve got two and can listen with them.
请根据下面短文回答： Open Time: 9:00 to 17:00 Tuesdays through Sundays(sales stop at 16:00) Ticket Prices: Full Price: RMB 30; Half Price: RMB 15 Free invitation tickets are distributed every Wednesday and shall not exceed the approved quota. The corresponding policies are: · 200 invitation tickets are freely distributed to the public every Wednesday. · Visitors shall go to the bamboo courtyard on the first underground floor east to pick up invitation tickets according to the order of the telephone reservation from 8:30 to 11:00 a.m. every Wednesday. · Staff of the museum will distribute the 200 free invitation tickets based on the order of the telephone reservation until the quota is used up. · Visitors shall get the free invitation ticket by using their valid certificate. Distribution is limited to per person. · Visitors using the free invitation ticket cannot visit the special exhibitions. Tickets are only valid on the date indicated. Year-round Free Admission Policies. · Retired people with the provision of their certificates of retirement · Disabled people with the provision of their certificates of disability · Disabled soldiers with the provision of their certificates of disability · Staff working in the culture and museum systems with the provision of their employment certificates · Children less than 120 cm in height and accompanied by adults (those without adult accompaniment will not be admitted and the accompanying adult must purchase a ticket as per regulations) Routes: Subway: Muxidi Station, Line 1 Buses: No.1, No.4 and Special Bus No.1 to the stop "Muxidi". Reservation Telephone: 63370491 63370492 The museum is open______.
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