Influence of Polyalkylmethacrylate VII on Boundary Film Formation,Friction,Wear and Efficiency of Lubricants

1 Influence of PAMAon Boundary Fil mFormation and Friction1.1 Experi mental methodsUltra-thin optical interferometry has been used tostudy thinlubricating fil ms for more than a decade and theexperi mental details of this technique have been reportedpreviously[1].The principle of the test setup is shown inFigure1.A polished steel ball is loaded and rolled againstthe flat surface of a glass disc that is coated with a thinsemi-reflecting chromiumlayer and a silica spacer of about500nmthickne…     

Vapor absorption by LiBr aqueous solution in vertical smooth tubes

Heat and mass transfer in a falling film vertical in-tube absorber was studied experimentally with LiBr aqueous solution. The presented results include the effect of solution flow rate, solution subcooling and cooling water temperature on the absorption in a smooth copper tube 16.05 mm I.D. and 400 mm long. The experimental data in the previous report for a 1200-mm-long tube was also re-examined and compared. It was demonstrated by the observation of the flow in the tube that the break down of the liquid film into rivulets leads to deterioration of heat and mass transfer at lower film Reynolds number or in longer tubes. An attempt to evaluate physically acceptable heat and mass transfer coefficients that are defined with estimated temperature and concentration at the vapor–liquid interface was also presented.     

Fatigue crack growth in SiC particulates reinforced Al matrix graded composite

The SiC/Al graded composite was fabricated by powder metallurgy processing and its fatigue crack growth behavior was studied. The volume percentage of SiC particulates was distributed from 5 to 30% layer by layer on the cross section. Since the aluminium was dissolved together, there was no evident interface between the two layers with different volume fraction of SiC particulates. Fatigue crack growth was in direction of from 5 to 30% SiC layers under sinusoidal wave-form. The retardation of fatigue crack growth was found when crack propagated from low volume fraction of SiC to high volume fraction of SiC. The crack deflection and branching between two layers were observed, which decreased crack growth rates. In view of crack tip driving force, the plasticity mismatch between the layers shielded crack tip driving force, i.e. decreased the effective J-integral at the tip of the crack as the plastic zone of the crack tip spread from the weaker material into the stronger material.     

金刚石膜在真空电子器件输出窗中的应用

综述了金刚石膜的性能和制备方法，着重介绍丁国内外常用的封接工艺，讨论了该材料在mm波器件中的应用前景。     

电子产品研制阶段可靠性增长试验研究

结合工程实际经验,深入讨论了可靠性增长过程及实现途径,在保持试验条件和改进过程不变的条件下,实施了对具体型号电子产品的可靠性增长试验,达到了预期的可靠性增长目标,并且利用可靠性增长试验的数学模型(AMSAA模型)来评估产品的可靠性增长,对开展可靠性增长与可靠性增长试验工作具有重要的实际意义.     

热声制冷机及其改进实验研究

热声制冷作为一种很有前途的制冷方法，在国内外相关领域引起了极大兴趣。热声制冷机由声发生器、共振管、板叠及高、低温换热器等部分组成。对声驱动器的振动膜及其冷却系统、气体弹簧系统、高、低温换热器进行了初步改进，使制冷机冷端温降从原来的12℃提高到27℃左右，这是目前国内报道的最大温降。     

Nonstationary Simulation Model of Absorber with Falling Film of Suspension

A nonstationary model of SO₂ absorption from a gas phase to a countercurrent falling film of absorbing slurry was developed. Laminar, wavy and turbulent film structures were considered based on published information. Resistances to the mass transfer on the gas and the liquid sides of the interphase were considered, together with chemical reactions in the liquid phase. Relevant chemical equilibria in the liquid phase were modeled. Original experimental data on the neutralization reagent dissolution rate presented as a polydispersed two‐phase system of solids and on the rate of dissolved sulfite oxidation were used. The model was verified with experimental data from a laboratory‐scale falling‐film absorber using a single vertical tube under various geometrical and operating conditions, and a very good agreement was found with the experiment. Parametric sensitivity analysis showed the critical parts of the model.     

一种新型的多功能照相胶片影像质量评价方法

本设计了一种新型的多功能照相胶片感光性能和影像质量评价方法。这种方法的主要特点的快速、方便并有满足 实用要求的精确度。该方法仅使用一个测试标板，就可以很容易地测定出照相胶片的感光性能、分辨率、均方根粒度和密度振幅响应（DAR）值等多种表征影像质量的参数。本简要介绍该方法并给出试验结果及其与传统测试方法的比较和讨论意见。     

PECVD法低温沉积多晶硅薄膜的研究

在玻璃衬底上采用常规的PKCVD法在低温(≤400℃)条件下制得大颗较(直径＞100nm)、择优取向(220)明显的多晶硅薄膜。选用的反应气体为SiF4和H2混合气体。加入少量的SiH4后，沉积速率提高了近10倍。分析认为，在低温时促使多晶硅结构形成的反应基元应是SiFmHn(m n≤3)，而不可能是SiHn(n≤3)基团。     

微桥法镍膜的弹性模量和残余应力测量

利用MEMS技术制作了不同尺寸的镍(Ni)膜微桥结构样品。采用纳米压痕仪XP系统测量了微桥载荷与位移的关系,并结合微桥力学理论模型得到了两种不同尺寸的Ni膜的弹性模量和残余应力。结果表明,两种不同尺寸的Ni膜的弹性模量结果一致,为190 GPa左右,但是残余应力变化较大。与采用纳米压痕仪直接测得的带有硅(Si)基底的Ni膜弹性模量186.8 7.5 GPa相比较,两者符合较好。