问题 单项选择题

关于收益率曲线叙述不正确的是( )。

A.将不同期限债券的到期收益率按偿还期限连接成一条曲线,即是债券收益率曲线
B.它反映了债券偿还期限与收益的关系
C.理论上,应当采用零息债券的收益率来得到收益率曲线,以此反映市场的实际利率期限结构
D.收益率曲线总是斜率大于零

答案

参考答案:D

解析: 收益率曲线的斜率可以小于零。故选D。

填空题

欧盟原定于2012年1月1日起征收航空碳排税以应对冰川融化和全球变暖,使得对如何降低大气中CO2的含量及有效地开发利用碳资源的研究显得更加紧迫。请运 用化学反应原理的相关知识研究碳及其化合物的性质。

(1)近年来,我国储氢纳米碳管研究取得重大进展,用电弧法合成的碳纳米管中常伴有大量碳纳米颗粒(杂质),这种碳纳米颗粒可用氧化气化法提纯,其反应的化学方程式为:

____C + ____K2Cr2O7 + ____→ ____CO2↑+ ____K2SO4 + ____Cr2(SO4)3 + ____H2O

请完成并配平上述化学方程式。

(2)甲醇是一种新型燃料,甲醇燃料电池即将从实验室走向工业化生产。工业上一般以CO和H2为原料合成甲醇,该反应的热化学方程式为:CO(g)+ 2H2(g)CH3OH(g)  △H1=-116 kJ/mol

①下列措施中有利于增大该反应的反应速率的是  _______;

A.随时将CH3OH与反应混合物分离       

B.降低反应温度    

C.增大体系压强                          

D.使用高效催化剂  

②已知:

 △H2=-283 kJ·mol-1       

 △H3=-242 kJ·mol-1

则表示1mol气态甲醇完全燃烧生成CO2和水蒸气时的热化学方程式为______________;

③在容积为1L的恒容容器中,分别研究在230℃、250℃和270℃三种温度下合成甲醇的规律。下图是上述三种温度下不同的H2和CO的起始组成比(起始时CO的物质的量均为1mol)与CO平衡转化率的关系。

请回答:

ⅰ)在上述三种温度中,曲线Z对应的温度是___________________;

ⅱ)利用图中a点对应的数据,计算出曲线Z 在对应温度下CO(g)+ 2H2(g)CH3OH(g) 的平衡常数K =__________。

(3)CO2在自然界循环时可与CaCO3反应,CaCO3是一种难溶物质,其Ksp=2.8×10-9。CaCl2溶液与Na2CO3溶液混合可形成CaCO3沉淀,现将等体积的CaCl2溶液与Na2CO3溶液混合,若Na2CO3溶液的浓度为7×10-4mol/L ,则生成沉淀所需CaCl2溶液的最小浓度为__________。

阅读理解

阅读理解。

     COLUMBUS, Ohio-The heart operation taking place in the pale-green operating room at the Ohio State

University Medical Center was unusual. The patient, a 62-year-old man, was made to sleep, tied with blue

drapes (消毒帷帘) and lying face up on a narrow table. But no one was touching him.

     Instead, the operation was being performed by a robot, whose three metal arms went through pencil-sized

holes in the man's chest. At the ends of the robot's arms were tiny metal fingers, with turning wrists, which

held tiny instruments, a light and a camera. The robot's arms and fingers were controlled by Dr. Randall K.

Wolf, sitting at a computer in a corner of the operating room about 20 feet away.

     This sort of operation, heart surgeons say, is the start of what may be the biggest change in their profession

since heart bypass surgery (心脏搭桥手术) began nearly 30 years ago. "The reason we make cuts is that we

have big hands," said Dr. Wolf, the director of the surgery at Ohio State. The robot's dainty fingers, no longer

than a nail on the small finger, at the end of the long sticks could work better.

     Eventually, surgeons believe, most heart surgery will be done by robots whose arms are put in through

pencil-sized holes punched in patients' chests. Instead of directly staring into a patient's body, surgeons will

view magnified images of the operation on computer screens. In theory, the doctor would not have to be in the

same room, or even the same country, as the patient.

1. In this passage, the underlined word "dainty" means ____.

A. small

B. weak

C. fat

D. quick

2. According to the passage, the reason that most operations require large cuts is that ____.

A. patients have large organs

B. surgeons have large hands

C. large cuts take less time

D. large cuts cost less money

3. The main idea of this passage is that heart surgery by robots ____.

A. is quicker than surgery done by doctors

B. was developed at Ohio State University

C. is a new and risky procedure

D. may replace surgery done by doctors

4. Based on the information in this passage, all of the following conclusions are true EXCEPT ____.

A. all doctors at Ohio State develop new surgical techniques

B. robot surgery is. being developed at Ohio State

C. robot surgery will be used on many patients in the near future

D. many hospitals will eventually offer robot surgery to patients