DKJ电动执行器位置发送器由哪几部分组成？其作用是什么？

用于评价人群健康状况较为敏感的指标是（）

A.出生率

B.死亡率

C.婴儿死亡率

D.人口期望寿命

E.伤残调整生命年

Antarctica and Environment

Antarctica has actually become a kind of space station – a unique observation post for detecting important changes in the world’s environment. Remote from major sources of pollution and the complex geological and ecological systems that prevail elsewhere, Antarctica makes possible scientific measurements that are often sharper and easier to interpret than those made in other parts of the world.

Growing numbers of scientists therefore see Antarctica as a distant-early-warning sensor, where potentially dangerous global trends may be spotted before they show up to the north. One promising field of investigation is glaciology. Scholars from the United States, Switzerland, and France are pursuing seven separate but related projects that reflect their concern for the health of the West Antarctic Ice Sheet – a concern they believe the world at large should share.

The Transantarctic Mountain, some of them more than 14,000 feet high, divide the continent into two very different regions. The part of the continent to the “east” of the mountains is a high plateau covered by an ice sheet nearly two miles thick. “West” of the mountain, the half of the continent south of the Americas is also covered by an ice sheet, but there the ice rests on rock that is mostly well below sea level. If the West Antarctic Ice Sheet disappeared, the western part of the continent would be reduced to a sparse cluster of island.

While ice and snow are obviously central to many environmental experiments, others focus on the mysterious “dry valley” of Antarctica, valleys that contain little ice or snow even in the depths of winter. Slashed through the mountains of southern Victoria Land, these valleys once held enormous glaciers that descended 9,000 feet from the polar plateau to the Ross Sea. Now the glaciers are gone, perhaps a casualty of the global warming trend during the 10,000 years since the ice age. Even the snow that falls in the dry valleys is blasted out by vicious winds that roars down from the polar plateau to the sea. Left bare are spectacular gorges, rippled fields of sand dunes, clusters of boulders sculptured into fantastic shapes by 100-mile-an-hour winds, and an aura of extraterrestrial desolation.

Despite the unearthly aspect of the dry valleys, some scientists believe they may carry a message of hope of the verdant parts of the earth. Some scientists believe that in some cases the dry valleys may soak up pollutants faster than pollutants enter them.

小题1:What is the best title for this passage?

A Antarctica and environmental Problems.

B Antarctica: Earth’s Early-Warning station.

C Antarctica: a Unique Observation Post.

D Antarctica: a Mysterious Place.

小题2:What would the result be if the West Antarctic Ice Sheet disappeared?

A The western part of the continent would be disappeared.

B The western part of the continent would be reduced.

C The western part of the continent would become scattered Islands.

D The western part of the continent would be reduced to a cluster of Islands.

小题3:Why are the Dry Valleys left bare?

A Vicious wind blasts the snow away.                B It rarely snows.

C Because of the global warming trend and fierce wind.  D Sand dunes.

小题4:Which of the following is true?

A The “Dry Valleys” have nothing left inside.

B The “Dry Valleys” never held glaciers.

C The “Dry Valleys” may carry a message of hope for the verdant.

D The “Dry Valleys” are useless to scientists.

计算等标排放量时，参数的选取正确的是( )。

A．如果计算等标排放量时，《环境空气质量标准》中没有相应的标准值选取，应选用TJ 36-79中的相应标准

B．对于只有日均浓度限值的大气污染物，c_0i一般可取日平均浓度限值的2倍

C．对于毒性大或可积累的致癌物质如苯、汞等，取日平均值的2倍

D．大气环境影响因子识别所选用的等标排放量计算公式，其所选用的环境空气质量标准为《环境空气质量标准》中的二级、1h平均值

科学化管理原理包括（）。

A.系统原理

B.人本原理

C.组织原理

D.动态原理

如何保管好树脂？