The rate of any chemical reaction, regardless of the temperature at which it takes place, usually depends on a very important characteristic known as its activation energy. Any molecule can be imagined to reside at the bottom of a so-called potential well of energy. Some chemical reaction corresponds to the transition of a molecule from the bottom of one potential well to the bottom of another. In classical chemistry, such a transition can be accomplished only by going over the potential barrier between the well, the height of which remain constant and is called the activation energy of the reaction. In tunneling, the reacting molecules tunnel from the bottom of one to the bottom of another well without having to rise over the harrier between the two wells. Recently researchers have developed the concept of tunneling temperature: the temperature below which tunneling transitions greatly outnumber Arrhenius transitions, and classical mechanics gives way to its quantum counterpart.
This tunneling phenomenon at very low temperatures suggested my hypothesis about a cold prehistory of life: formation of rather complex organic molecules in the deep cold of outer space, where temperatures usually reach only a few degrees Kelvin. Cosmic rays might trigger the synthesis of simple molecules, such as interstellar formaldehyde, in dark clouds of interstellar dust. Afterward complex organic molecules would be formed, slowly hut surely, by means of tunneling. After I offered my hypothesis, Hoyle and Wickramashinghe argued that molecules of interstellar formaldehyde have indeed evolved into stable polysaccharides such as cellulose and starch. Their conclusions, although strongly disputed, have generated excitement among investigators such as myself who are proposing that the galactic clouds are the places where the prebiological evolution of compounds necessary to life occurred.
The author is mainly concerned with ______.
A.describing how the principles of classical chemistry were developed
B.initiating a debate about the kinds of chemical reaction required for the development of life
C.explaining how current research in chemistry may be related to broader biological concerns
D.clarifying inherent ambiguities in the laws of classical chemistry
第1题
A.《十四经发挥》
B.《针灸大成》
C.《针灸甲乙经》
D.《针灸大全》
E.《针灸聚英》
元代滑伯仁于公元1341年著:
第2题
明代针灸学家杨继洲著:
A.《十四经发挥》
B.《针灸大成》
C.《针灸甲乙经》
D.《针灸大全》
E.《针灸聚英》
第3题
现存最早的针灸学专著是()
A.《内经》
B.《针灸甲乙经》
C.《针灸大全》
D.《十四经发挥》
E.《针灸大成》
第4题
现存最早的针灸学专著是()
A.《灵枢经》
B.《针灸甲乙经》
C.《针灸大全》
D.《十四经发挥》
E.《针灸大成》
第6题
下列哪项叙述是错误的:
A.皇甫谧著《针灸甲乙经》
B.杨继洲著《针灸大成》
C.徐凤著《针灸大全》
D.高武著《十四经发挥》
E.李时珍著《奇经八脉考》
第7题
被称为"针经"的针灸学著作是()
A、《灵枢》
B、《针灸甲乙经》
C、《针灸大成》
D、《针灸大全》
E、《十四经发挥》
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