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 Woods Hole, 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. 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!

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Look After Your Voice Often speakers at a meeting experience dry mouths and ask for a glass of water. You can solve the problem by activating the saliva in your mouth. First gently bite the edges of your tongue with your teeth. Or, press your entire tongue to the bottom of your mouth and hold it there until the saliva flow. Or you can imagine that you are slicing a big juicy lemon and sucking the juice. Before you begin your talk, be kind to your voice. Avoid milk or creamy drinks which coat your throat. Keep your throat wet by drinking a little sweetened warm tea or diluted fruit juice. If you sense that you are losing your voice, stop talking completely. Save your voice for your speech. You may feel foolish using paper to write notes, but the best thing you can do is to rest your voice. If you need to see a doctor, perhaps you can get some advice from a professional singer. In the meantime, do not even talk in a low voice. What about drinking alcohol to wet your throat? I advise you not to touch alcohol before speaking. The problem with alcohol is that one drink gives you a little confidence. The second drink gives you even more confidence. Finally you will feel all-powerful and you will feel you can do everything, but in fact your brain and your mouth do not work together properly. Save the alcohol until after you finish speaking. Perhaps you want to accept the advice, but you may wonder if you can ever change the habits of a lifetime. Of course you can. Goethe, who lived before indoor skating rinks or swimming pools, said, “We learn to skate in the summer and swim in the winter. “ Take this message to heart and give yourself time to develop your new habits. If you are willing to change, you will soon be able to say that you will never forget these techniques because they became a part of your body.

A. overuse face masks B. deal with the mask problem seriously C. rub their faces and noses in the subway D. protest against the mask guidelines E. help protect people from being attacked by a flu F. announce the results of their mask research

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 Woods Hole, 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. 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!

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Face Masks May Not Protect from Super-flu 1 If a super-flu strikes, face masks may not protect you. Whether widespread use of masks will help, or harm, during the next worldwide flu outbreak is a question that researchers are studying furiously. No results have come from their mask research yet. However, the government says people should consider wearing them in certain situations anyway, just in case. 2 But it’ s a question the public keeps asking while the governments are making preparations for the next flu pandemic. So the Centers for Disease Control and Prevention(CDC)came up with(提出)preliminary guidelines(初步指导方针). “We don’t want people wearing them everywhere, “ said the CDC. “The overall recommendation really is to avoid exposure. 3 When that’ s not possible, the guidelines say to consider wearing a simple surgical mask if you are in one of the three following situations. First, you’ re healthy and can’t avoid going to a crowded place. Second, you’ re sick and think you may have close contact with the healthy, such as a family member checking on you. Third, you live with someone who’ s sick and thus might be in the early stages of infection, but still need to go out. 4 Influenza pandemic can strike when the easy-to-mutate flu virus shifts to a strain that people never have experienced. Scientists cannot predict when the next pandemic will arrive, although concern is rising that the Asian bird flu might trigger one if it starts spreading easily from person to person. 5 During the flu pandemic, you should protect yourself. Avoid crowds, and avoid close contact with the sick unless you must care for someone. Why aren’ t masks added to this self-protection list? Because they can help trap virus-laden(含有病毒的、充满细菌的)droplets flying through the air with a cough or sneeze. Simple surgical masks only filter the larger droplets. Besides, the CDC is afraid masks may create a false sense of security. Perhaps someone who should have stayed home would don an ill-fitting mask and hop on the subway instead. 6 Nor does flu only spread through the air. Say someone covers a sneeze with his or her hand, then touches a doorknob or subway pole. If you touch that spot next and then put germy hands on your nose or mouth, you’ ve been exposed. It’ s harder to rub your nose while wearing a mask and so your face may get pretty sweaty under masks. You reach under to wipe that sweat, and may transfer germs caught on the outside of the mask straight to the nose. These are the problems face masks may create for their users. 7 Whether people should or should not use face masks still remains a question. The general public has to wait patiently for the results of the mask research scientists are still doing. A. Reasons for Excluding Masks From the Self-protection List B. Effort to Stop Flu From Spreading C. When to Use Face Masks D. Guideline on Mask Use E. Warnings From the CDC F. Danger of Infection Through Germy Hands and Masks

Can Buildings Be Designed to Resist Terrorist Attack? In the aftermath of the terrorist attack on the World Trade Center, structural engineers are trying hard to solve a question that a month ago would have been completely unthinkable: Can buildings be designed to withstand catastrophic blasts inflicted by terrorists? Ten days after the terrorist attacks on the twin towers, structural engineers from the University at Buffalo and the Multidisciplinary Center for Earthquake Engineering Research(MCEER)headquartered at UB traveled to ground zero as part of a project funded by the National Science Foundation. Visiting the site as part of an MCEER reconnaissance visit, they spent two days beginning the task of formulating ideas about how to design such structures and to search for clues on how to do so in buildings that were damaged but still are standing. “Our objective in visiting ground zero was to go and look at the buildings surrounding the World Trade Center, those buildings that are still standing, but that sustained damage, “ said M. Bruneau, Ph. D. “Our immediate hope is that we can develop a better understanding as to why those buildings remain standing, while our long-term goal is to see whether earthquake engineering technologies can be married to existing technologies to achieve enhanced performance of buildings in the event of terrorist attacks, “ he added. Photographs taken by the investigators demonstrate in startling detail the monumental damage inflicted on the World Trade Center towers and buildings in the vicinity. One building a block away from the towers remains standing, but was badly damaged. “This building is many meters away from the World Trade Center and yet we see a column there that used to be part of that building, “ explained A. Whittaker, Ph. D. “The column became a missile that shot across the road, through the window and through the floor. The visit to the area also revealed some surprises, according to the engineers. For example, the floor framing system in one of the adjacent buildings was quite rugged, allowing floors that were pierced by tons of falling debris to remain intact. “Highly redundant ductile(有延展性的)framing systems may provide a simple , but robust strategy for blast resistance, “ he added. Other strategies may include providing alternate paths for gravity loads in the event that a load-bearing column fails. “We also need a better understanding of the mechanism of collapse, “ said A. Whittaker. “We need to find out what causes a building to collapse and how you can predict it. “ A. Reinhorn, Ph. D. noted that “Earthquake shaking has led to the collapse of many buildings in the past. It induces dynamic response and extremely high stresses and deformations in structural components. Solutions developed for earthquake-resistant design may be directly applicable to blast engineering and terrorist-resistant design. Part of our mission now at UB is to transfer these solutions and to develop new ones where none exist at present.

Cell Phone Lets Your Secret Out Your cell phone holds secrets about you. Besides the names and 【C1】______that you’ ve programmed into it, traces of your DNA linger on the device, according to a new study. DNA is genetic: material that 【C2】______in every cell. Like your fingerprint, your DNA is unique to you—【C3】______you have an identical twin. Scientists today routinely analyze DNA in blood, saliva, or hair left 【C4】______at the scene of a crime. The results often help detectives identify【C5】______and their victims. Your cell phone can reveal more about you 【C6】______you might think. Meghan J. McFadden, a scientist at McMaster University in Hamilton, Ontario, heard about a crime in which the suspect bled onto a cell phone and later dropped the 【C7】______. This made her wonder whether traces of DNA lingered on cell phones even when no blood was involved.【C8】______she and colleague Margaret Wallace of the City University of New York analyzed the flip-open phones of 10 volunteers. They used swabs to collect 【C9】______traces of the users from two parts of the phone: the outside, where the user holds it, and the 【C10】______, which is placed at the user’ s ear. The scientists scrubbed the phones using a solution made mostly 【C11】______alcohol. The aim of washing was to remove all detectable traces of DNA. The owners got their phones 【C12】______for another week. Then the researchers collected the phones and repeated the swabbing of each phone once more. The scientists discovered DNA that 【C13】______to the phone’ s speaker on each of the phones. Better samples were collected from the outside of each phone, but those swabs also picked up DNA that belonged to other people who had apparently also handled the phone.【C14】______, DNA showed up even in swabs that were taken immediately after the phones were scrubbed. That suggests that washing won’t remove all traces of evidence from a criminal’ s device. So cell phones can now be added to the【C15】______of clues that can clinch a crime-scene investigation.

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Backpacks are convenient because______.

What is the most important feature of the backpack invented by Lawrence C. Rome and his colleagues?

The word “springs“ in Paragraph 3 means______.

According to Paragraph 4, what does Rome plan to do?

What is implied in “if you do get one eventually, just make sure to look both ways before crossing the street!“ ?