问题 问答题 简答题

钛的精炼方法及基本原理?

答案

参考答案:

碘化法:碘化法利用碘几乎不溶于钛但能够与钛反应,其产物能够在高温下热分解的原理得到高纯钛,它是目前生产超高纯度钛的主要方法之一。

电子束熔炼法:电子束熔炼法以电子束为加热源使原料熔化,高真空有利于去除钛合金中的低熔点挥发性金属杂质,起到提纯效果。

区域熔炼法:利用高频线圈或聚焦红外线加热烧结棒的局部使熔区从一端逐渐移至另一端以完成结晶过程。利用杂质在金属凝固态和熔融态的溶解度差别使杂质析出或改变其分布而得到高纯金属。

熔盐电解法:熔盐电解法一般以碱金属卤化物熔盐作为电解质,以粗钛或钛合金作为阳极,在一定析出电位下使原料以钛离子形式溶入电解质中,并迁移至阴极在阴极析出高纯钛。

单项选择题
单项选择题

In order to understand, however imperfectly, what is meant by "face", we must take (1) of the fact that, as a race, the Chinese have a ply (2) instinct. The theatre may almost be said to be the only national amusement, and the Chinese have for theatricals a (3) like that of the Englishman (4) athletics, or the Spaniard for bull-fights. Upon very slight provocation, any Chinese regards himself in the (5) of an actor in a drama. He throws himself into theatrical attitudes, performs the salaam, falls upon his knees, prostrates himself and strikes his head upon the earth, (6) circumstances which to an Occidental seem to make such actions superfluous, (7) to say ridiculous. A Chinese thinks in theatrical terms. When roused in self-defense he addresses two or three persons as if they were a multitude. He exclaims: "I say this in the presence of You, and You, and You, who are all here present. " If his troubles are adjusted he (8) of himself as having "got off the stage" with credit, and if they are not adjusted he finds no way to "retire from the stage". All this, (9) it clearly understood, has nothing to do with realities. The question is never of facts, but always of (10) . If a fine speech has been (11) at the proper time and in the proper way, the requirement of the play is met. We are not to go behind the scenes, for that would (12) all the plays in the world. Properly to execute acts like these in all the complex relations of life, is to have "face". To fail them, to ignore them, to be thwarted in the performance of them, this is to " (13) face". Once rightly apprehended, "face" will be found to be in itself a (14) to the combination lock of many of the most important characteristics of the Chinese.

It should be added that the principles which regulate "face" and its attainment are often wholly (15) the intellectual apprehension of the Occidental, who is constantly forgetting the theatrical element, and wandering (16) into the irrelevant regions of fact. To him it often seems that Chinese "face" is not unlike the South Sea Island taboo, a force of undeniable potency, but capricious, and not reducible to rule, deserving only to be abolished and replaced by common sense. At this point Chinese and Occidentals must agree to (17) , for they can never be brought to view the same things in the same light. In the adjustment of the incessant quarrels which distract every hamlet, it is necessary for the "peace-talkers" to take a careful account of the (18) of "face" as European statesmen once did of the balance of power. The object in such cases is not the execution of even-handed justice, which, even if theoretically desirable, seldom (19) to an Oriental as a possibility, but such an arrangement as will distribute to all concerned "face" in due proportions. The same principle often applies in the settlement of lawsuits, a very large percentage of which end in what may be called a (20) game.

(16)()

A.up

B.off

C.down

D.out