51系列单片机40脚DIP封装的第14引脚功能是（）A、计数器0输入 B、计数器1输

闸阀全开时的当量长度为（）。

A.3

B.5

C.7

D.9

天门冬氨酸的pK1=2.09、pK2=9.82、pKR=3.86，其pI是（）。

A.5.955

B.7.73

C.5.96

D.6.84

E.2.98

简述调速汽门失常的处理。

为提高噪声污染防治力度，长沙城区基本实施机动车禁鸣是哪个区域内？

[A] Even as the robots do their work (officials should know within a day whether the robots were successful), BP is preparing to drill a relief well into which the original well would empty. That could allow the company to inject a heavy fluid into the broken well that would slow and eventually stop the flow of oil. Once the leak is stanched, BP could permanently seal the first well.

[B] The explosion on the Deepwater Horizon oil rig last week in the Gulf of Mexico was without question a human tragedy. The day after the rig finally sank on April 22, the Coast Guard called off the search for the 11 workers lost during the accident.

[C] But the Gulf’s $ 2.4 billion fishing industry could be imperiled by a major spill, as could tourism up and down the Gulf Coast and potentially the Florida panhandle (狭长地带). "We are being very, very aggressive," said Tony Hayward, the CEO of BP, which expects to spend some $100 million on the cleanup. "This is the biggest response by anyone in the industry ever, and we’re able to do it because we planned for it. We will be judged by our response. "

[D] Now the accident threatens to become an environmental tragedy as well. Despite early hopes that the oil spill could be minimized, the rig’s fractured drilling pipe is currently leaking 42,000 gal. of crude a day. The result is an oil slick on the surface of the water, covering more than 1,800 sq. miles, now just 20 miles from the delicate Gulf coastline. Depending on wind conditions, oil could begin washing up on the shore as early as this weekend.

[E] The Coast Guard and the energy giant BP, which operated the sunken rig and is responsible for the cleanup, have launched a massive operation to contain the spill—an unusual challenge, considering the complexity of underwater drilling. First, remote-controlled robot submarines have been deployed to try to seal off the oil well altogether by activating a massive device called a blowout preventer. If the 450-ton valve at the wellhead can be turned on, the oil flow should stop, and the spill could be ended quickly. But the outcome is far from guaranteed; robots have never been used in an operation of this magnitude nor at this depth—some 5,000 ft. below the surface of the ocean.

[F] Cleanup has already been under way. Vessels are dragging long booms (拦油栅) to corral the oil on the surface—which is still a thin slick, not yet a thick tar—white the planes spray chemical dispersants that can separate the crude from the water. Coast Guard officials said they would consider a controlled burn of the oil. Pools of oil would be trapped in containment booms and set on fire. The burning oil would also create a plume of smoke and air pollution, which could affect flying birds. But according to the National Oceanic and Atmospheric Administration, marine wildlife would be less harmed by a burning area of the ocean than by exposure to an oil slick.

[G] But the entire operation would likely take months, during which time the oil would keep spilling. So BP is also preparing to build a massive dome that could be placed over the oil leaks—which are emanating from a pipe that connects the well to the sunken rig—and actually collect the leaking crude. The only problem is that such an enterprise has never been attempted in deep water, and it would take at least two weeks to be put in place.

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