成型换品种时应注意的事项?

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问题:

成型换品种时应注意的事项?

考点:生化化工药品技能考试石蜡工艺考试石蜡工艺考试题库
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某学习小组为探究导电溶液的电阻在体积相同时,电阻值与长度的关系。选取了一根乳胶管,里面灌满了盐水,两端用粗铜丝塞住管口,形成一段封闭的盐水柱。进行了如下实验:

(1)该小组将盐水柱作为纯电阻,粗测其电阻约为几千欧。现采用伏安法测盐水柱的电阻,有如下实验器材供选择:

A.直流电源:电动势12V,内阻很小,额定电流为1A;

B.电流表A1:量程0~10mA,内阻约10Ω;

C.电流表A2:量程0~600 mA,内阻约0.5Ω;

D.电压表V:量程0~15V,内阻约15kΩ;

E.滑动变阻器R1:最大阻值10Ω;

F.滑动变阻器R2:最大阻值5kΩ;

G.开关、导线等。

在可供选择的器材中,应选用的电流表是___________(填“A1”或“A2”),应该选用的滑动变阻器是___________(填“R1”或“R2”)。

(2)该小组已经完成部分导线的连接,请你在实物接线图中完成余下导线的连接。

(3)握住乳胶管的两端把它均匀拉长,多次实验测得盐水柱长度L、电阻R的数据如下表:

为了研究电阻R与长度L的关系,该小组用纵坐标表示电阻R,作出了如图所示的图线,你认为横坐标表示的物理量是___________。

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青霉素的抗菌作用机制是

A.与细菌细胞膜结合,破坏细胞膜结构

B.破坏细胞壁使水分内渗

C.抑制DNA多聚酶,影响DNA的合成

D.与转肽酶结合,阻止细胞壁黏肽合成

E.抑制菌体蛋白的合成

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求由曲线y=2-x2、y=2x-1及x≥0围成的平面图形的面积A,以及此平面图形绕x轴旋转一周所得旋转体的体积Vx

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阅读理解。

     Three months after the government stopped issuing (发放) or renewing permits for Internet cafes because

of security (安全) concerns, some cafe owners are having financial (经济的) concerns of their own.

     The permits were stopped suddenly three months ago by the government until new safeguards could be put

in place to prevent misuse of the information superhighway, but for cafe owners it's a business breakdown with no fix in sight.

     "I handed in a request to open up an Internet café and received the conditions," said the businessman

Obeidallah."I rented a place in the Sharafiah district at SR45,000 and prepared the place with equipment that

cost me more than SR100,000. When I went to the local government after finishing everything, I was surprised

to find that they'd stopped issuing permits for Internet cafes."

     Having an Internet cafe without Internet is much like having a coffee shop without coffee. "I'm avoiding

closing the place, but it's been more than three months with the situation ongoing as it is." Obeidallah said. "Who will bear the losses caused by the permit issue?"

     The decision took many cafe owners by surprise."I asked to open an Internet café, and I was handed a list

of all the things that were needed to follow through, such as a sign for the place, filling out forms," said

Hassan Al-Harbi.

     "I did all that was asked and rented a place. And after the Haj vacation I went to the local government and

they surprised me, saying that there are new rules that forbid the issuing of any more Internet cafe permits and

that one can't even renew his permit. I've lost more than SR80,000," Al-harbi added.

     As for the government, officials say a method to deal with it is on the way. But security concerns come

before profit (盈利).

1. The government stopped issuing or renewing permits for Internet cafes _____.

A. to prevent misuse of new safeguards in Internet cafes

B. to make cafe owners earn less profit from their business

C. to stop the use of the information superhighway on Internet

D. to make sure of the proper use of the information superhighway

2. The government's decision led to the fact that many cafe owners _____.

A. suffered heavy financial losses

B. asked to open up Internet cafes

C. continued to operate Internet cafes

D. asked the government for payment

3. The underlined phrase in the last paragraph "on the way" means _____.

A. to be studied

B. to be put into practice

C. to be changed

D. to be improved

4. The cafe owners found the government's decision _____.

A. suprising and unacceptable

B. understandable and acceptable

C. reasonable but surprising

D. surprising but acceptable

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