管束

Another feature of HEDDTB is that its tubes' buddle is composed of tubes with different diameters, which lead to a smaller fluctuation of heat transfer coefficient in the condition of fluctuating flux than that of the heat exchanger with tubes that has the same diameter in the case of low Reynolds number.

异径管束换热器的换热管束由直径不同的管子组成，这种换热管束在低雷诺数下传热系数随流量的波动相对同径管束而言较小，因此异径管束有一定的抗传热系数波动的性能，这使得换热器在流量波动的工况下工作性能稳定。

It is shown that the mechanical properties including Young's modulus, tensile strength, critical strain and stress under buckling can be enhanced with the decreasing of intershell spacing. The shear strength can be enhanced by 2-3 orders of magnitude when the intershell spacing is reduced to 20%, which is also dependent on commensuration. Zigzag-type carbon nanotubes have higher shear strength. The axial stress in tubes when the load transferring from outmost tube to inner tube is observed as well.

研究了单壁纳米管束横截面的六方化失稳现象，给出各种管径的面内压力－应变关系曲线；每条曲线都给出一个明显的拐点而且有很强的非线性；线弹性模量与参考构形有关，也受管直径的影响；分析了管束横截面的晶格不稳定性特征，表明晶格的缺陷能够明显的减小临界值；模拟了在不同应变下纳米管束对静水压的反应，发现不同压力下的截面形态不同，在很高压力下相邻管之间会形成化学键。

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。

We also studied the total energy and the enthalpy of the different structure after the transition, and found that the parallel structure is more favorable than the herringbone structure.

我们还指出，相变后平行排列的纳米管束结构能降低体系的总能量和焓，而另一种人字形排列的管束结构则是相变后的一种亚稳结构。

The change of condenser steam flow field causes the changes of its heat transfer coefficient and the vapor lock,with the analysis on the change of the tube bundle arrangement with the alteration of the steam flow field,proposed the change scope of the correction factor of the arrangement of condenser tube bundle with the alteration of the condenser steam flow field.

凝汽器蒸汽流场的变化使其传热系数和汽阻发生变化，传热系数和汽阻的改变使凝汽器管束布置修正系数随着负荷变化，分析了管束布置修正系数随蒸汽流场的变化而变化，提出了管束布置修正系数随蒸汽流场变化的范围。

These base-associated microtubules is comprise of membranlle brackets of AZM,its associated oral rib-wall microtubules, base body brackets of UM,anterior longitudinal microtubulesand posterior longitudinal microtubules of frontal cirri,ALM of TC,ALM,PLM and transverse microtubules of midventral cirri and L-and RMC.

其中，口围带小膜托架及其相联系的肋壁微管和波动膜基体托架，额棘毛基部前纵微管束、后纵微管束及横棘毛基部前纵微管束，中腹棘毛及左、右缘棘毛基部前纵微管束、后纵微管束和横微管束是该纤毛虫皮层纤毛器基部的主要附属微管。

The water chamber takes the shape of tilting cube, in favor of uniform distribution of cooling water on tube plate surface. The tube bundle is divided into two groups of zygomorphy according to the bisection system and it has eight support clapboards. The siphonopore center of each clapboard increases a certain distance corresponding to that of two tube plates and the cooling tube takes the shape of arch. The two-way cooling water of bisection flows through the condenser in opposite direction so as to improve the distribution of heat load for tube bundle. Around the throat of condenser, the final stage low-pressure heater, air extraction tube, intake device of bypass exhaust and the like are deployed.

它的特点是：水室呈倾斜立方体形状，有利于冷却水流在管板面上均匀分布；由于采用对分制，管束相应地分为左、右对称的两组，并且管束设有八块支撑隔板，每块隔板的管孔中心相对于两端管板的管孔中心依次抬高一定的距离，以使冷却管呈拱形状；对分制的两路冷却水以相反方向流过凝汽器，从而改善管束的热负荷分布；在凝汽器喉部布置了末级低压加热器，抽汽管道及旁路排汽接受装置等。

Set up the baffle plate for condensation water in tube bundle to reduce and avoid the condensate recooling by lower tube bundle in the falling process of upper tube bundle.

在管束中设置凝结水挡板，以避免和减少上部管束下落的凝结水受到下部管束的再冷却。

The experimental and analytical results show that the axial rigidity of the corrugated pipe is 23.0 percent of the bare pipe with the same thickness and diameter,and the thermal compensation performance of the former is 2.27 times the latter's under equal-stress condition.By using corrugated pipe bundle instead of the bare pipe bundle with the same stiffness as its tube sheet,the axial thermal compensation can be increased by 40.4 percent,and the corresponding pulling-out force is 53.2 percent of that of the bare pipe bundle.

研究结果表明，波节换热管单管的刚度为相应光管的23.4%；在最大应力相同的条件下，波节换热管的轴向热补偿量为相应光管的2.27倍；在光管管束与壳体等刚度条件下，用波节管管束代替光管管束，轴向热补偿量可提高40.4%，相应的拉脱力为光管管束的53.2%。

Anticorrosive process of surface evaporation air cooler using LLSTD-1 as coating media,which solves two major difficult problems in large scale bundle anticorrosive techniques:performance requirements on coating materials (heat conduction,high temperature resistance,oil-proof and scale inhibition)and the coating method on surface evaporation air cooler bundles.

以LLSID-1涂料为涂层介质对大型表面蒸发空冷器管束进行防腐处理，解决了大型管束防腐的两大难题，一是对涂层材料的性能要求(耐腐、耐温、耐油、阻垢、传热效果好)；二是解决了大型管束防腐工艺(用什么方法将涂料涂装在表面蒸发空冷器管束上)。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。