共查询到18条相似文献,搜索用时 140 毫秒
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1)本发明专利号8710344.3. 本发明涉及气体激光管的阴极,为气体激光管提供了一种球形整体结构镀铝阴极.阴极壳与激光管用同一种玻璃质材料制成一体.在阴极壳内表面镀上一层铝膜作为阴极,该铝膜覆盖整个球形内表面.伸入该球形整体结构阴极内部的激光管的放电毛细管,与该球形阴极壳的一个开口的伸入部分相交错并连通,该伸入部分的端口位于该球形整体结构阴极的球心附近,能使该球形阴极表面各处的放电电流密度相对于该放电管开口是均匀分布的,从而减少了阴极溅射,保证气体的重新释放与气体的俘获达到平衡,降低了“气体清除”效应,延长了气体激… 相似文献
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采用数值模拟的方法,研究了沸腾雾化喷射过程中热壁面薄液膜层受到液滴碰撞扰动时液膜层内汽泡运动,相界面变化和由此引起的壁面换热特性.模拟结果显示汽泡生长初期相界面变化与液膜层内二次核化特征与文献结果吻合良好,汽泡生长后期相界面变化存在滞后.讨论了液滴下降速度.液滴直径与初始位置,多液滴碰撞对液膜层内流动与壁面换热的影响. 相似文献
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为调控固化过程中双重乳液内径的变化和降低聚-α-甲基苯乙烯(PAMS)微球的表面粗糙度,研究了双重乳液固化过程中内外水相中电解质浓度对水在油相液膜中迁移和分相行为的影响。结果表明:仅在外水相中添加电解质时,内水相的渗透压高于外水相,使得内相水向外水相迁移,导致固化后的微球表面起皱。当在内外水相同时添加电解质时,由于平衡了三相之间水的化学势,抑制了水在油相液膜中的迁移和分相,导致PAMS微球壳壁内气泡体积和数量显著降低。同时,在内外水相中同时添加不同浓度的电解质,还可显著改善双重乳液三相之间的密度匹配度,从而提高微球的球形度和壁厚均匀性。 相似文献
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液体雾化被广泛应用于工业、农业等领域,雾化过程中液体首先形成液膜,液膜在气液边界层内出现不稳定,导致液膜破碎。因此液膜的不稳定性对液体雾化起着非常重要的作用,有必要对液膜的不稳定性进行研究。采用数值计算的方法对可压缩气体中黏性平面液膜的不稳定性进行了研究,首先对黏性平面液膜和气体的速度分布进行推导,在此基础上采用谱方法对黏性平面液膜的不稳定性进行了研究。研究发现:在正弦和曲张模式下,施加电场会加速平面液膜的破碎;正弦模式比曲张模式更加不稳定,说明正弦模式在平面液膜不稳定中起主导作用;气体Mach数、电Euler数、气体Reynolds数、 Weber数和动量通量比的增加会加速液膜的破裂;随着气体边界层与液膜厚度比和液体Reynolds数的增加,扰动波的增长速率降低,液膜变得更加稳定。 相似文献
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本文介绍一种用马赫-陈德干涉系统测量模拟合成孔径雷达数据片波差的方法.该法能把两种原因产生的波差区分开来,即把通过胶片变形的波面与平面参考波面比较,求出胶片厚度不平产生的波差;把合成孔径雷达数据片的一级衍射波面与两个半径不等的参考球面波比较,分别求出由模拟装置产生的方位维和斜距维波差.本文给出一些实验结果和分析.这种方法还可以用于测量真实合成孔径雷达数据片的波差.由胶片厚度变化产生的波差可以用液体门补偿.但是,在实际中使用液体门是很繁复的,有时也没有必要.因此,我们认瑞利准则出发导出合成孔径雷达数据片胶片厚度变化产生的波差的容限,以此作为判断是否要用液体门的依据. 相似文献
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在考虑空气阻力影响,确定液滴撞击球面速度的基础上,对较高韦伯数液滴撞击干燥球面动态行为过程进行了实验研究,分析了球面曲率与韦伯数对液滴撞击行为和铺展因子的影响,并与前人撞击平面结果进行了对比.实验表明,靠近撞击球面时,液滴降落速度出现明显波动;球面曲率对液滴撞击后行为影响明显,曲率较大时,液滴撞击后铺展液膜会超出球面直径并滑落,曲率较小时,液滴撞击后在球面上呈现明显的铺展、回缩、震荡、着附动态变化行为,此时最大铺展因子受曲率影响小,随曲率减小,逐渐趋向于撞击平面时的最大铺展因子;韦伯数对液膜铺展速率影响较小,但对液膜回缩时间影响明显,最大铺展因子随韦伯数增加逐渐增大,获得的关联式呈指数变化. 相似文献
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A. Nold A. Malijevsky S. Kalliadasis 《The European physical journal. Special topics》2011,197(1):185-191
In this Letter we examine an effective interfacial Hamiltonian approach for wetting phenomena based on two different density
approximations in the framework of a density functional theory. The system under consideration is an attractive spherical
wall subject to adsorption by a metastable liquid. We argue that, contrary to a planar geometry, in the spherical case the
popular sharp-kink approximation leads to a considerable disagreement for the film thickness with numerical results obtained
from density functional theory. We show that the deviation originates from the inaccuracy of the predicted liquid-gas surface
tension. We further demonstrate that the prediction can be substantially improved when a soft-interface approximation is adopted,
such that the liquid-gas interface is approximated by a smooth monotonic function. 相似文献
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《Heat Recovery Systems and CHP》1993,13(5):441-449
In this investigation, an equation is theoretically developed to predict the Nusselt number and hence the collapse rate of large spherical two-phase bubbles condensing in quiescent immiscible liquid. Heat transfer from the thin film of condensate and in the wake is determined. Theoretical prediction and experimental data show satisfactory agreement. A parametric study is also carried out for different parameters affecting the collapse rate. 相似文献
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We investigate the efficiency of inertial fusion target compression, where at the initial time moment the thermonuclear fuel
is in a two-phase state and has the form of two adjacent layers — the external DT-liquid layer and the internal DT-ice layer.
We study this problem for the fast ignition targets, where the ultimate final density of the thermonuclear matter is of a
special importance. We take the simplest type of a fast ignition target, which corresponds to the technical justification
of the HiPER Project aimed at demonstrating fast ignition at the compressing laser pulse energy ~100 kJ. Such a target presents
a spherical DT-ice shell coated with a thin polymer film. We obtain the dependence of the final target density on the mass
fraction of the DT-matter liquid phase and formulate the requirements on the admissible concentration of liquid phase if the
decrease in the DT-fuel final density does not exceed 10%. We find the criterion for choosing the laser-pulse duration which
provides the minimum decrease in the final density of the target containing DT-matter in the initial two-phase state. 相似文献
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Flow characteristics of a liquid film flowing over a smooth surface and structured surface with the Reynolds number range from 10 to 1121 are studied. The mixture of R21 and R114 refrigerants is used as the test liquid. The 3D transient simulations are taken to capture the liquid film’s dynamic characteristics and spatial distribution. Effects of the inlet dimension, inlet flow rates, surface tension, and surface structuring on the wettability, average velocity, and film thickness are studied systematically. The obtained results show that surface tension is essential for an accurate simulation, while inlet width has no effect on the liquid film parameters in the steady-state flow regime. For low flow rates, wetting area and film thickness both are small, and a suggested range of Reynolds number is chosen to simulate further heat transfer in order to balance the film thickness and dry spots generation. It is shown that a ripple surface structure hinders the liquid film movement, reflected in a lower velocity and a larger film thickness compared to the smooth surface. Lateral movement of a liquid film can also be observed at the structured surface. 相似文献