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四大措施解决千年冻土问题 2006年7月1日，青藏铁路实现了全线贯通，打破了美国的火车旅行家保罗?“有昆仑山脉在，铁路就永远进不了拉萨”的断言，大长了中国人的志气． 在修建青藏铁路时，需要解决两大难题：一是铁路要穿越“千年冻土”区，需要保证路基的稳定性；二是高原气压低、氧气含量低，需要保证施工人员及乘客的安全性．我国科技工作者在解决两大难题上做出了许多创新和发明．四大措施解决千年冻土问题 ①热棒：天然“制冷机”：进入两大滩冻土区，路基两旁插有一排排碗口粗细、2m的铁棒（如图）．铁棒间隔2m，一直向前延伸，我们称它热棒．热棒在路基下还有5m，整个棒体是中空的，里面灌有液氨，棒的顶端是散热片，这样棒体就相当于一个天然“制冷机”． ②抛石路基：廉价“土空调”：在青藏铁路路基内部，还有一种廉价而有效的“土空调”，在土层路基中间，填筑了一定厚度的碎石，保证了冻土层的温度不随外界气温的变化而变化，从而保护了冻土的完好性． ③遮阳板：隔热“外衣”：遮阳板路基是在路基的边坡和坡石上架设一层用于遮挡太阳辐射的板材，完全消除太阳对路基的辐射加热作用． ④以桥代路：“最后绝招”（如图）：增氧机解决高原气压低、氧气含量低的问题在沿途建立氧气制造站、列车配有完整的供氧系统等，确保了施工人员的旅客的乘车的舒适度． （1）通过阅读材料，谈谈青藏铁路蕴含的物理知识（至少举出两点）______． （2）试分析说明，天然“制冷机”（或廉价“土空凋”）的工作原理______．
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【单选题】已知E Ө (Cr 2 O 7 2- /Cr 3+ )>E Ө (Fe 3+ /Fe 2+ )>E Ө (Cu 2+ /Cu)>E Ө (Fe 2+ /Fe),则上述诸电对的各物种中最强的氧化剂和最强的还原剂分别为( )。
A.
Cr 2 O 7 2- ,Fe 2+
B.
Cr 2 O 7 2- ,Fe
C.
Fe 3+ ,Cu
D.
Cu 2+ ,Fe 2+
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【单选题】E Ө (Mn 2+ /Mn)=-1.029 V , E Ө (Cu 2+ /Cu)=0.342 V , E Ө (Ag + /Ag)=0.799 V , 判断氧化剂强弱的顺序是:
A.
Ag + >Mn 2+ >Cu 2+ ；
B.
Cu 2+ >Mn 2+ >Ag + 。
C.
Mn 2+ >Cu 2+ >Ag + ；
D.
Ag + >Cu 2+ >Mn 2+ ；
查看完整题目与答案
【单选题】已知 E Ө (Fe 3+ / Fe 2+ ) =+ 0.77 v , E Ө (Br 2 / Br - ) =+ 1.07 v , E Ө (H 2 O 2 / H 2 O) =+ 1.78 v , E Ө (Cu 2+ / Cu) =+ 0.34 v , E Ө (Sn 4+ / Sn 2+ ) =+ 0.15 v ,则在标准态下能共存的是
A.
Fe 3+ ， Cu
B.
Fe 3+ ， Br 2
C.
Sn 2+ ， Fe 3+
D.
H 2 O 2 ， Fe 2+
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【单选题】Which of the following statements is true? I.If young firms are struggling to obtain funding from underdeveloped financial markets, the most efficient policy solution would be a production subsidy. II...
A.
a. I only
B.
b. I and II
C.
c. II and III
D.
d. II only
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【单选题】__________ refers to the cost of something that is not directly involved in making a particular product or providing a particular service, for example the cost of renting building or of training staff
A.
financial gains
B.
payroll taxes
C.
benefits
D.
overhead costs
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【简答题】已知: Cu 2+ ———Cu + ——Cu , E Ө (Cu 2+ / Cu )= 0.34V , E Ө (Cu 2+ / Cu+ )=0.158V, 则反应 Cu + Cu 2+ =2Cu + 的 E 为 _________V 。(保留到小数点后第3位)
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【单选题】计算机网络给我们提供大量有益的信息,也带来许多毫无价值的信息,甚至传播一些有悖于社会道德规范的东西。这启示我们( )
A.
要坚持一分为二的观点
B.
要用不同的方法解决不同的矛盾
C.
任何矛盾都是有主有次的
D.
看问题只要看到好的方面
查看完整题目与答案
【单选题】An important advantage of on-the-job training is that it
A.
provides immediate transfer of training
B.
allows employees to learn at their own rate without any pressure to produce
C.
provides for greater group interaction
D.
reduces the costs of supervision
查看完整题目与答案
【单选题】为了及时、正确地计算产品成本,企业应做好的各项基础工作不包括()
A.
选择适当的成本计算方法
B.
材料物资的计量、收发、领退和盘点
C.
做好各项原始记录工作
D.
定额的制定和修订
查看完整题目与答案
【单选题】Consider the following game: Raquel is an employee, he has to choose whether to pursue training that costs £1 to herself or not. Vera is an employer, he has to decide whether to pay a fixed wage of £1...
A.
There are two players in the game, they are Raquel and Vera.
B.
Raquel’s strategies are “Training” and “No Training”, Vera’s strategies are “Fixed wage” and “Revenue sharing”.
C.
If Raquel choose strategy “No Training” and Vera choose strategy “Revenue sharing”, their payoffs are (11, 11)
D.
If Raquel choose strategy “Training” and Vera choose strategy “Fixed wage”, their payoffs are (9, 10)
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相关题目：
【单选题】已知E Ө (Cr 2 O 7 2- /Cr 3+ )>E Ө (Fe 3+ /Fe 2+ )>E Ө (Cu 2+ /Cu)>E Ө (Fe 2+ /Fe),则上述诸电对的各物种中最强的氧化剂和最强的还原剂分别为( )。
A.
Cr 2 O 7 2- ,Fe 2+
B.
Cr 2 O 7 2- ,Fe
C.
Fe 3+ ,Cu
D.
Cu 2+ ,Fe 2+
查看完整题目与答案
【单选题】E Ө (Mn 2+ /Mn)=-1.029 V , E Ө (Cu 2+ /Cu)=0.342 V , E Ө (Ag + /Ag)=0.799 V , 判断氧化剂强弱的顺序是:
A.
Ag + >Mn 2+ >Cu 2+ ；
B.
Cu 2+ >Mn 2+ >Ag + 。
C.
Mn 2+ >Cu 2+ >Ag + ；
D.
Ag + >Cu 2+ >Mn 2+ ；
查看完整题目与答案
【单选题】已知 E Ө (Fe 3+ / Fe 2+ ) =+ 0.77 v , E Ө (Br 2 / Br - ) =+ 1.07 v , E Ө (H 2 O 2 / H 2 O) =+ 1.78 v , E Ө (Cu 2+ / Cu) =+ 0.34 v , E Ө (Sn 4+ / Sn 2+ ) =+ 0.15 v ,则在标准态下能共存的是
A.
Fe 3+ ， Cu
B.
Fe 3+ ， Br 2
C.
Sn 2+ ， Fe 3+
D.
H 2 O 2 ， Fe 2+
查看完整题目与答案
【单选题】Which of the following statements is true? I.If young firms are struggling to obtain funding from underdeveloped financial markets, the most efficient policy solution would be a production subsidy. II...
A.
a. I only
B.
b. I and II
C.
c. II and III
D.
d. II only
查看完整题目与答案
【单选题】__________ refers to the cost of something that is not directly involved in making a particular product or providing a particular service, for example the cost of renting building or of training staff
A.
financial gains
B.
payroll taxes
C.
benefits
D.
overhead costs
查看完整题目与答案
【简答题】已知: Cu 2+ ———Cu + ——Cu , E Ө (Cu 2+ / Cu )= 0.34V , E Ө (Cu 2+ / Cu+ )=0.158V, 则反应 Cu + Cu 2+ =2Cu + 的 E 为 _________V 。(保留到小数点后第3位)
查看完整题目与答案
【单选题】计算机网络给我们提供大量有益的信息,也带来许多毫无价值的信息,甚至传播一些有悖于社会道德规范的东西。这启示我们( )
A.
要坚持一分为二的观点
B.
要用不同的方法解决不同的矛盾
C.
任何矛盾都是有主有次的
D.
看问题只要看到好的方面
查看完整题目与答案
【单选题】An important advantage of on-the-job training is that it
A.
provides immediate transfer of training
B.
allows employees to learn at their own rate without any pressure to produce
C.
provides for greater group interaction
D.
reduces the costs of supervision
查看完整题目与答案
【单选题】为了及时、正确地计算产品成本,企业应做好的各项基础工作不包括()
A.
选择适当的成本计算方法
B.
材料物资的计量、收发、领退和盘点
C.
做好各项原始记录工作
D.
定额的制定和修订
查看完整题目与答案
【单选题】Consider the following game: Raquel is an employee, he has to choose whether to pursue training that costs £1 to herself or not. Vera is an employer, he has to decide whether to pay a fixed wage of £1...
A.
There are two players in the game, they are Raquel and Vera.
B.
Raquel’s strategies are “Training” and “No Training”, Vera’s strategies are “Fixed wage” and “Revenue sharing”.
C.
If Raquel choose strategy “No Training” and Vera choose strategy “Revenue sharing”, their payoffs are (11, 11)
D.
If Raquel choose strategy “Training” and Vera choose strategy “Fixed wage”, their payoffs are (9, 10)
查看完整题目与答案