查询词典 structure constant

In the single crystal of C60 with a FCC structure,positron mainly appears outside the C60 molecule.The main annihilation space is the interspace between molecules.The calculated positron bulk lifetime in C60 is 352ps, which agrees with experiment value of 356ps in literature.In carbon nanotube bundles with different dimeters,as the diameter of carbon nanotubes increases,the main space where positron appears changes from the interspace of carbon tubes to the space inside carbon tubes,the radio between positron annihilation with valence eletrons and core eletrons becomes larger,the positron bulk lifetime in carbon nanotube increase rapidly first and come to be a constant at the end.The calculated positron lifetime of carbon nanotube with a dimeter of 0.8～1.6ns is 332～470ps,which agrees with the experiment value of 394ps.Positron annihilation has been studied in widly used compound semiconductors.

计算结果表明：在片层结构的石墨晶体中，正电子主要在石墨层间的空隙中湮没，计算出的石墨中的正电子寿命为208 pS，与文献中的实验结果215 ps符合很好；在金刚石单晶中，正电子主要在碳原子之间的空隙中存在并发生湮没，计算出的金刚石中的正电子寿命为115 ps，文献中的实验结果110 ps左右符合；在面心立方结构的C60晶体中，正电子主要在C60分子球壳内外侧及分子之间存在，C60球形分子中心正电子分布很少，正电子的湮没区域集中在C60分子之间的空隙区域，计算出的C60中的正电子寿命为352 ps与文献中的实验结果356ps相符合；对于不同管径碳米管束中的正电子分布，随着碳纳米管直径的增加，碳纳米管束中的正电子由主要在碳纳米管管间的区域出现转变为主要在碳纳米管管内中心的区域出现：碳纳米管束中的正电子与碳原子的价电子的湮没概率变得越来越大，与核心电子的湮没概率变得越来越小；碳纳米管束中正电子的湮没寿命先迅速增大，而后趋于一定值。

SEM and XRD reveal that the CA crystallized film have larger grains and lattice constant of garnet than the RTA crystallized film, which implies that in the CA crystallized film more bismuth ions substitute into the dodecahedral site in the garnet structure.

至于两种薄膜的法拉第旋转峰的偏移，初步认为是由于两种薄膜的石榴石相晶格大小不同，造成晶体场强度的不同，使得与磁光跃迁相关的基态和激发态之间的能量差有所差异。

It was also found that the film of smaller grains corresponded to a smaller lattice constant of the garnet structure, which implied that fewer Bi〓 ions substituted into the dodecahedral sites in the garnet, due to the fact that the smaller grains resulted in more grain boundaries, thus leading to more serious Bi segregation in the grain boundaries.

分析表明，细小的晶粒意味着薄膜中含有更多的晶界，这样将导致Bi组分在晶界上的偏析较显著，而进入石榴石结构中氧十二面体间隙的Bi〓较少，对于Bi，Al∶DyIG来说，石榴石相晶格常数与{Bi〓}〓呈正相关关系，由此可以解释具有细小晶粒的薄膜对应较小的石榴石相晶格常数。

The electronic structure, the equilibrium lattice constant and body elastic module of ScN, TiN and VN are investigated comparing with other's theoretical and experimental results.

研究了ScN、TiN和VN的平衡晶格常数和体弹性模量，并分析了其电子结构。同实验结果进行了比较，同其他人的理论结果进行了比较。

The relation of deformation of tunnel structure with the load was clearly linear elastic,so the effective rigidity of shield tunnel was constant in elastic stage,which was agreeable to the rule of the modified conventional d...

对上海地铁盾构隧道的研究表明，通缝拼装时刚度有效率为0.67，错缝拼装时刚度有效率为0.75，软弱土体抗力对隧道有效刚度的影响可以忽略。

The extraction equilibrium constant of the extractant is closely related with its chemical structure.

研究表明，空间参数是影响酚类络合剂萃取性能的主要参数。

Effect of exfoliation on structure and tensile strength of LC4CS aluminum alloy at constant temperature.

恒温剥蚀对LC4CS铝合金结构和力学性能的影响。

By applying the proposed control law to discrete-time variable structure control systems, the stability of origin and steady of systems are better than the exponential rate reaching law and proportional-constant-variable rate reaching law.

应用该趋近设计变结构控制系统，其原点的稳定性和系统的平稳性都优於指数趋近律和比例－等速－变速趋近律。

On the basis of the kinetic equation of substrate reaction in the presence of urea or guanidine hydrochloride, all microscopic kinetic constants for the free enzyme and enzyme-substrate binary and ternary complexes have been determined. The results of the present studies indicate that:①In the presence of urea or guanidine hydrochloride, enzyme-substrate complexes lose their activity less rapidly than the free enzyme. Therefore, both substrates, NADPH and 7, 8-dihydrofolate, protect dihydrofolate reductase against inactivation.②The denaturation of dihydrofolate reductase by urea follows single-phase kinetics, and changes in enzyme activity and tertiary structure proceed simultaneously in the unfolding process, so it may be an"all or none"process.③The GdnHCl-induced unfolding of the dihydrofolate shows a biphasic transition, while the change in the enzyme activity is a single exponential process. The rate constant of inactivation is consistent with that of the fast conformational change. Therefore, the kinetic intermediate of protein unfolding should be a partially folded and inactive form.

我们根据在脲或盐酸胍存在下的底物反应动力学方程求得游离酶和酶底物二元、三元复合物的微观动力学常数，结果表明：①酶-底物二元、三元复合物的失活速度明显慢于游离酶，说明两个底物二氢叶酸和NADPH对酶的失活都具有一定程度的保护作用；②在脲作用下，酶的失活和构象变化均为单指数项过程，而且酶的活力丧失和三级结构变化是同时发生的，说明二氢叶酸还原酶的脲变性可能是一个"全或无"的两态过程；③在盐酸胍作用下，酶的构象变化为两相过程，而失活则是单指数项过程，酶分子构象变化的快相速度常数与失活速度常数基本一致，因此我们认为二氢叶酸还原酶的盐酸胍变性过程中存在一个没有活力、但仍具备一定空间结构的变性中间体。

City space structure is in the process of constant development, and its development needs so many drives force function.

城市空间结构处于不断演进过程中，城市空间结构的演进要受到众多驱动力的推动作用。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。