判断题The processors in a multiprocessor system communicate with each other through shared variable in a common memory.

判断题Truck bill of lading is a non-negotiable document of title stating the point of origin, destination , consignee , and other pertinent information.

判断题The Letter of credit shall be examined only by the exporter.

判断题Copying Birds May Save Aircraft Fuel Both Boeing and Airbus have trumpeted the efficiency of their newest aircraft, the 787 and A350 respectively. Their clever designs and lightweight composites certainly make a difference. But a group of researchers at Stanford University, led by Ilan Kroo, has suggested that airlines could take a more naturalistic approach to cutting jet-fuel use, and it would not require them to buy new aircraft. The answer, says Dr. Kroo, lies with birds. Since 1914, scientists have known that birds flying in formation—a V-shape—expend less energy. The air flowing over a bird"s wings curls upwards behind the wingtips, a phenomenon known as upwash. Other birds flying in the upwash experience reduced drag, and spend less energy propelling themselves. Peter Lissaman, an aeronautics expert who was formerly at Caltech and the University of Southern California, has suggested that a formation of 25 birds might enjoy a range increase of 71%. When applied to aircraft, the principles are not substantially different. Dr. Kroo and his team modeled what would happen if three passenger jets departing from Los Angeles, San Francisco and Las Vegas were to assemble over Utah, assume an inverted V formation, occasionally change places so all could have a turn in the most favourable positions, and proceed to London. They found that the aircraft consumed as much as 15% less fuel (coupled with a reduction in carbon-dioxide output). Nitrogen-oxide emissions during the cruising portions of the flight fell by around a quarter. There are, of course, knots to be worked out. One consideration is safety, or at least the perception of it. Would passengers feel comfortable traveling in companion? Dr. Kroo points out that the aircraft could be separated by several nautical miles, and would not be in the intimate groupings favoured by display teams like the Red Arrows. A passenger peering out of the window might not even see the other planes. Whether the separation distances involved would satisfy air traffic-control regulations is another matter, although a working group at the International Civil Aviation Organisation has included the possibility of formation flying in a blueprint for new operational guidelines. It remains to be seen how weather conditions affect the air flows that make formation flight more efficient. In zones of increased turbulence, the planes" wakes will decay more quickly and the effect will diminish. Dr. Kroo says this is one of the areas his team will investigate further. It might also be hard for airlines to co-ordinate the departure times and destinations of passenger aircraft in a way that would allow them to gain from formation flight. Cargo aircraft, in contrast, might be easier to reschedule, as might routine military flights. As it happens, America"s armed forces are on the case already. Earlier this year the country"s Defence Advanced Research Projects Agency announced plans to pay Boeing to investigate formation flight, though the programme has yet to begin. There are reports that some military aircraft flew in formation when they were low on fuel during the Second World War, but Dr. Lissaman says they are unsubstantiated. "My father was an RAF pilot and my cousin, the skipper of a Lancaster, lost over Berlin," he adds. So he should know.

判断题There are two levels of web portals identified in the passage: information and communication.

判断题If a buyer accepts any part of an indivisible unit of goods, he is considered to have accepted the whole unit.

判断题According to Uniform Customs and Practice for Documentary Credits, about should be interpreted as not exceeding 5/% of the total quantity.

判断题The Internet plays an important part in the growth of multimedia ideas.

判断题According to UCP 600

判断题Demurrage is the extra charge a shipper pays for detaining a freight car or ship beyond time permitted for loading or unloading.

判断题Assembly language is machine language.

判断题Meeting the needs of the teachers is the cornerstone of effective distance education programs.

判断题There are altogether five key players in distance education mentioned by the author.

判断题If a letter of credit is not confirmed by another bank , it is called an unconfirmed credit. But the wordunconfirmedis should be indicated in the credit. ( )

判断题A programmed computer can do as much as the software controlling it enables it to do.

判断题Network games can only be played by individuals.

判断题Education and support for the patients and families are part of the work of multimedia.

判断题Health care can be improved by multimedia and telemedicine in several ways.