求问36套excercise16的12题

蜜与奶罐头UID: 3109467

答案是C，可是我认为若要形成crystalline structure,取非以后应该是冷却更快呀！
求牛人解释

蜜与奶罐头UID: 3109467

自己顶

dandelionttUID: 2852417

请楼主发问的时候把文章和题目一并贴出来，以方便版友为你解答，谢谢。

蜜与奶罐头UID: 3109467

好的。文：When a molten metal or metallic alloy is cooled to a
solid, a crystalline structure is formed that depends on the
particular alloy composition. In contrast, molten
Line nonmetallic glass-forming materials, when cooled, do not
5  assume a crystalline structure, but instead retain a
structure somewhat like that of the liquid--an amorphous
structure. At room temperature, the natural long-term
tendency for both types of materials is to assume the
crystalline structure. The difference between the two is inthe kinetics or rate of formation of the crystalline structure, which is controlled by factors such   as the nature
of the chemical bonding and the ease with which atoms
move relative to each other. Thus, in metals, the kinetics
favors rapid formation of a crystal line structure, whereas
in nonmetallic glasses the rate of formation is so slow that
almost any cooling rate is sufficient to result in an
amorphous structure.

蜜与奶罐头UID: 3109467

It can be inferred from the passage that, theoretically,
molten nonmetallic glasses assume a crystalline
structure rather than an amorphous structure only if
they are cooled                                                      
(A) very evenly, regardless of the rate
(B) rapidly, followed by gentle heating
(C) extremely slowly
(D) to room temperature
(E) to extremely low temperatures

蜜与奶罐头UID: 3109467

谢谢了

轻薄的假象UID: 3264386

6# 蜜与奶罐头
原文引述“Thus, in metals, the kinetics favors rapid formation of a crystal line structure, whereas in nonmetallic glasses the rate of formation is so slow that almost any cooling rate is sufficient to result in an amorphous structure.”
由这段话可知，nonmetallic形成 crystal line structure的速度太慢了，以至于任意的冷却速度都能导致最后形成的是amorphous structure 而非crystal line structure。由此可知，是因为形成crystal的速度相对于冷却速度太慢了才导致形成 amorphous structure。如果要形成crystal的话，需要他的形成速度相对于冷却速度提高，那怎么办呢？此消彼长我们将冷却速度降得很低即可。希望对楼主有帮助。

蜜与奶罐头UID: 3109467

明白了。十分感谢！:loveliness: