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【单选题】
以下几个聚合物中Tg最小的是A.
聚碳酸酯
B.
聚苯乙烯
C.
聚对苯
D.
聚苯醚
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【单选题】有机溶剂沉淀法是在生物大分子溶液中加入一定量的亲水性有机溶剂，使溶质的溶解度降低而沉淀析出的过程，下列说法错误的是（）。
A.
有机溶剂沉淀法的常用亲水溶剂为乙醇、丙酮和甲醇等
B.
亲水性有机溶剂丙酮的沉淀能力比乙醇强
C.
亲水性有机溶剂乙醇的浓度达70%以上时才能把目的产物沉淀出来
D.
亲水性有机溶剂丙酮的浓度达70%以上时才能把目的产物沉淀出来
【单选题】有机溶剂沉淀法即向水溶液中加入一定量的( )的有机溶剂,可( )溶质的溶解度使其沉淀被析出。
A.
亲水性,提高
B.
亲水性,降低
C.
疏水性,提高
D.
疏水性,降低
【简答题】旅游活动的产生必须有两个前提,一个是 前提,一个是 前提。
【简答题】Tina was a seen-year-old girl who always wore a bright smile. She got a serious disease and had to use a walker most of the time. People didn’t speak to __ __ very often. Maybe it was because she...
【简答题】In 2004，the World Health Organization，WHO，warned of a possible outbreak of another serious disease which may be even more deadly than SARS．The WHO believes that it is likely that bird flu will spread ...
【单选题】动脉血压在 80 ~ 180mmHg 范围内波动时,肾血流量能保持不变,这是由
A.
肾血流量的自身调节
B.
神经调节
C.
体液调节
D.
神经和体液共同调节
E.
神经 – 体液调节
【单选题】某植物花色是由一对呈中间显性的基因控制的,一种纯合体为深蓝色花,另一种纯合体为白花,杂合体为浅蓝色花。如果深蓝色花与浅蓝花进行杂交,其子代的表型为( )
A.
全部浅蓝花
B.
1/2浅蓝花，1/2深蓝花
C.
全部深蓝花
【单选题】In tests for Pironoma, a serious disease, a false positive result indicates that people have Pironoma when, in fact, they do not; a false negative result indicates that people do not have pironoma whe...
A.
The accepted treatment for Pironoma does not have damaging side effects.
B.
The laboratory test that has the lowest proportion of false positive results causes the same minor side effects as do the other laboratory tests used to detect Pironoma.
C.
In treating Pironoma patients, it is essential to begin treatment as early as possible, since even a week of delay can result in loss of life.
D.
The proportion of inconclusive test results is equal for all laboratory tests used to detect Pironoma.
E.
All laboratory tests to detect Pironoma have the same proportion of false negative results.
【单选题】动脉血压在80~180mmHg范围内波动时,肾血流量保持不变,这是由于
A.
肾血流量的自身调节
B.
神经调节
C.
体液调节
D.
神经和体液共同调节
E.
神经–体液调节
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