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The oceans, which cover nearly three-quarters of Earth’s surface, remain largely unexplored because of their vastness and inaccessibility to us air breathers. Webb Research of East Falmouth, Massachusetts, hopes to open up much of that mystery field with a new underwater vehicle that is pushed ahead solely by the ocean itself, so it can potentially study the watery depths for years at a time. Such long-lasting detectors may someday form fleets that provide up-to-minute data for weather forecasting. In the past, such autonomous underwater vehicles, or AUVs, have been battery powered and therefore required frequent recharges that limited their distance and depth of travel. Webb’s Slocum glider(滑翔机) hopes to solve this problem. "We conceived of a thermally powered engine to get the energy from the colder deep water of the ocean and the shallower warm water," Clayton Jones, an engineer at Webb Research, explains. "We picked out a material that undergoes a state change between those two temperatures in the ocean." When cold, this form-shifting substance is a compact solid. When warm, it expands and becomes a less dense liquid. The material’s expansion in warmer waters charges an internal mechanism that acts like stored power to control its buoyancy: by pumping mineral oil in and out of an external air bag, it alters its volume but maintains its weight. "The glider takes up more volume and becomes lighter than the water around it--less dense," Jones says. Scientists can also fit the Slocum glider with a variety of different sensory equipment and Global Positioning Systems. Each time it surfaces, it can raise its tail antenna(天线) to transmit data to and receive instructions from researchers sitting comfortably in their cozy offices. The glider will have its first test in salt water at the end of this September. The gliders could also get through and follow previously unstudied phenomena such as small underwater eddies (漩涡), which are vital to understanding water transport and heat flow in the ocean and therefore play an important role in storm formation and other weather development. "We have all these data snapshots(快照) from floats that just flow with the deep ocean current," Jones says. "To be able to fly through eddy sections, then transport with the whole eddy itself as it moves through the ocean, would be a very nice phenomenon to take a look at.\ Which of the following is true about the newly-designed AUV
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The oceans, which cover nearly three-quarters of Earth’s surface, remain largely unexplored because of their vastness and inaccessibility to us air breathers. Webb Research of East Falmouth, Massachusetts, hopes to open up much of that mystery field with a new underwater vehicle that is pushed ahead solely by the ocean itself, so it can potentially study the watery depths for years at a time. Such long-lasting detectors may someday form fleets that provide up-to-minute data for weather forecasting. In the past, such autonomous underwater vehicles, or AUVs, have been battery powered and therefore required frequent recharges that limited their distance and depth of travel. Webb’s Slocum glider(滑翔机) hopes to solve this problem. "We conceived of a thermally powered engine to get the energy from the colder deep water of the ocean and the shallower warm water," Clayton Jones, an engineer at Webb Research, explains. "We picked out a material that undergoes a state change between those two temperatures in the ocean." When cold, this form-shifting substance is a compact solid. When warm, it expands and becomes a less dense liquid. The material’s expansion in warmer waters charges an internal mechanism that acts like stored power to control its buoyancy: by pumping mineral oil in and out of an external air bag, it alters its volume but maintains its weight. "The glider takes up more volume and becomes lighter than the water around it--less dense," Jones says. Scientists can also fit the Slocum glider with a variety of different sensory equipment and Global Positioning Systems. Each time it surfaces, it can raise its tail antenna(天线) to transmit data to and receive instructions from researchers sitting comfortably in their cozy offices. The glider will have its first test in salt water at the end of this September. The gliders could also get through and follow previously unstudied phenomena such as small underwater eddies (漩涡), which are vital to understanding water transport and heat flow in the ocean and therefore play an important role in storm formation and other weather development. "We have all these data snapshots(快照) from floats that just flow with the deep ocean current," Jones says. "To be able to fly through eddy sections, then transport with the whole eddy itself as it moves through the ocean, would be a very nice phenomenon to take a look at.\ The disadvantage of traditional underwater vehicles is their ______.
The oceans, which cover nearly three-quarters of Earth’s surface, remain largely unexplored because of their vastness and inaccessibility to us air breathers. Webb Research of East Falmouth, Massachusetts, hopes to open up much of that mystery field with a new underwater vehicle that is pushed ahead solely by the ocean itself, so it can potentially study the watery depths for years at a time. Such long-lasting detectors may someday form fleets that provide up-to-minute data for weather forecasting. In the past, such autonomous underwater vehicles, or AUVs, have been battery powered and therefore required frequent recharges that limited their distance and depth of travel. Webb’s Slocum glider(滑翔机) hopes to solve this problem. "We conceived of a thermally powered engine to get the energy from the colder deep water of the ocean and the shallower warm water," Clayton Jones, an engineer at Webb Research, explains. "We picked out a material that undergoes a state change between those two temperatures in the ocean." When cold, this form-shifting substance is a compact solid. When warm, it expands and becomes a less dense liquid. The material’s expansion in warmer waters charges an internal mechanism that acts like stored power to control its buoyancy: by pumping mineral oil in and out of an external air bag, it alters its volume but maintains its weight. "The glider takes up more volume and becomes lighter than the water around it--less dense," Jones says. Scientists can also fit the Slocum glider with a variety of different sensory equipment and Global Positioning Systems. Each time it surfaces, it can raise its tail antenna(天线) to transmit data to and receive instructions from researchers sitting comfortably in their cozy offices. The glider will have its first test in salt water at the end of this September. The gliders could also get through and follow previously unstudied phenomena such as small underwater eddies (漩涡), which are vital to understanding water transport and heat flow in the ocean and therefore play an important role in storm formation and other weather development. "We have all these data snapshots(快照) from floats that just flow with the deep ocean current," Jones says. "To be able to fly through eddy sections, then transport with the whole eddy itself as it moves through the ocean, would be a very nice phenomenon to take a look at.\ The power of the new AUV is stored in the ______.
Reality television is a kind of television programming which, it is claimed, presents unscripted dramatic or humorous situations, documents actual events, and features ordinary people rather than professional actors. It could be described as a form of artificial or heightened documentary. Although it has existed in some form or another since the early years of television, the current explosion of popularity dates from around 2000. Reality television covers a wide range of television programming formats, from game or quiz shows which resemble the crazy, often demeaning (贬低人的) programs produced in Japan in the 1980s and 1990s, to monitor focused productions such as Big Brother. Critics say that the term "reality television" is somewhat of a misnomer (误称) and that such shows frequently portray a modified and highly influenced form of reality, with participants put in special locations or abnormal situations, sometimes coached to act in certain ways by off-screen handlers, and with events on screen manipulated through editing and other post-production techniques. Part of reality television’s appeal is due to its ability to place ordinary people in extraordinary situations. For example, on the ABC show, The Bachelor, a male dates a dozen women at the same time, traveling on extraordinary dates to scenic places. Reality television also has the potential to turn its participants into national celebrities, outwardly in talent and performance programs such as Pop Idol, though frequently Survivor and Big Brother participants also reach some degree of celebrity. Some critics have said that the name "reality television" is an inaccurate description for several styles of program included in the kind. In competition-based programs such as Big Brother and Survivor, and other special-living-environment shows like The Real World, the producers design the format of the show and control the day-to-day activities and the environment, creating a completely fabricated(杜撰的) world in which the competition plays out. Producers specifically select the participants, and use carefully designed plots, challenges, events, and settings to encourage particular behaviors and conflicts. Mark Burnett, creator of Survivor and other reality shows, has agreed with this assessment, and avoids the word "reality" to describe his shows; he has said, "I tell good stories. It really is not reality TV. It really is unscripted drama.\ Reality TV appeals to some people because it ______.
Reality television is a kind of television programming which, it is claimed, presents unscripted dramatic or humorous situations, documents actual events, and features ordinary people rather than professional actors. It could be described as a form of artificial or heightened documentary. Although it has existed in some form or another since the early years of television, the current explosion of popularity dates from around 2000. Reality television covers a wide range of television programming formats, from game or quiz shows which resemble the crazy, often demeaning (贬低人的) programs produced in Japan in the 1980s and 1990s, to monitor focused productions such as Big Brother. Critics say that the term "reality television" is somewhat of a misnomer (误称) and that such shows frequently portray a modified and highly influenced form of reality, with participants put in special locations or abnormal situations, sometimes coached to act in certain ways by off-screen handlers, and with events on screen manipulated through editing and other post-production techniques. Part of reality television’s appeal is due to its ability to place ordinary people in extraordinary situations. For example, on the ABC show, The Bachelor, a male dates a dozen women at the same time, traveling on extraordinary dates to scenic places. Reality television also has the potential to turn its participants into national celebrities, outwardly in talent and performance programs such as Pop Idol, though frequently Survivor and Big Brother participants also reach some degree of celebrity. Some critics have said that the name "reality television" is an inaccurate description for several styles of program included in the kind. In competition-based programs such as Big Brother and Survivor, and other special-living-environment shows like The Real World, the producers design the format of the show and control the day-to-day activities and the environment, creating a completely fabricated(杜撰的) world in which the competition plays out. Producers specifically select the participants, and use carefully designed plots, challenges, events, and settings to encourage particular behaviors and conflicts. Mark Burnett, creator of Survivor and other reality shows, has agreed with this assessment, and avoids the word "reality" to describe his shows; he has said, "I tell good stories. It really is not reality TV. It really is unscripted drama.\ People have criticized reality television because ______.
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