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问题 单项选择题

某1mol理想气体在温度T=273.15K时等温可逆体积膨胀为原来的3倍，则这一过程的焓变为（）。

A.△H=2494.9J·mol-1

B.△H=-2494.9J·mol-1

C.△H=Q

D.△H=0

答案

参考答案：D

单项选择题 A1/A2型题

关于免疫透射比浊分析，下列描述错误的是（）

A.基本原理是测定一定体积的溶液通过的光线量，由于溶液中抗原抗体复合物粒子对光线反射和吸收，透射光减少，测定的光通量与抗原抗体复合物的量呈反比

B.溶液中存在的抗原抗体复合物分子应足够大，分子太小则阻挡不了光线的通过

C.溶液中抗原抗体复合物的数量不需要太多，以免影响光通量的测定

D.检测仍需抗原抗体反应的温育时间，检测时间较长

E.测量的是透过不溶性复合物到达探测器而未被散射或吸收的光线
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单项选择题

Border Gateway Protocol(BGP) is inter-autonomous system （71） protocol. BGP is based on a routing method called path vector routing. Distance vector routing is not a good candidate for inter-autonomous system routing because there are occasions on which the route with the smallest （72） count is not the preferred route. For example, we may not want a packet through an autonomous system that is not secure even though it is shortest route. Also, distance vector routing is unstable due to the fact that the routers announce only the number of hop counts to the destination without defining the path that leads to that （73） . A router that receives a distance vector advertisement packet may be fooled if the shortest path is actually calculated through the receiving router itself. Link （74） routing is also not a good candidate for inner-autonomous system routing because an internet is usually too big for this routing method. To use link state routing for the whole internet would require each router to have a huge link state database. It would also take a long time for each router to calculate its routing （75） using the Dijkstra algorism.

74（）

A．status

B．search

C．state

D．research
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