内燃机车曲轴中频淬火过程的数值模拟

借助 ANSYS大型有限元分析软件 ,实现了 16 V2 4 0曲轴淬火过程的计算机模拟 ,模拟结果可直观地显示出任一时刻曲轴表面及内部的温度分布、冷却曲线以及淬火结束后的残余应力分布 ,并能预测淬硬层深度。同时对比了轴颈内圆角处进行淬火和不进行淬火两种工艺的效果 ,为现场提供了用虚拟现实方法详尽分析和研究淬火工艺的工具。     

Effects of fluoropolymer addition to an epoxy on scratch depth and recovery

Samples were prepared by addition of a fluorinated poly(aryl ether ketone) (12F-PEK) to a commercial epoxy resin and curing at either 24 °C or 70 °C. The concentrations of fluoropolymer in the samples were 0, 5, 10, 20, 30, 40, and 50%. Phase inversion facilitates the formation of more and more smooth surfaces for scratch testing with increasing fluoropolymer concentration. A progressively increasing load from 0.03 N to 12 N was administered with a diamond tip to the surfaces of the samples; depths were determined within ±7.5 nm. The original scratch depth is a function of the fluoropolymer concentration. Scratch recovery (healing) reaches values up to 95%. Plots of the residual depth versus concentration of the fluoropolymer at 4, 6, 8, and 10 N reveal minima for all forces and both temperatures. Addition of only 5% or 10% 12F-PEK improves the scratch recovery significantly. The results are explained by changes of material morphology with the fluoropolymer concentration. Electronic Publication     

导电相和固化剂对铜系导电涂料性能的影响

利用IR、SEM等手段,较详细地研究了铜粉–环氧树脂体系中固化剂与铜粉的相互作用,并探讨了铜粉用量、形状对涂料导电性能的影响规律。结果表明:固化剂(最佳用量为20%左右)可以通过形成配合物的反应,有效除去铜粉表面的氧化物,极大改善涂料导电性,使填充75%铜粉的体系具有约0.2×104Ω·m的体积电阻率。应用渗流模型和导电通道理论分析铜粉的用量、形状对涂料导电性能的影响规律。     

气体悬浮焙烧炉内衬烘炉曲线的确定

根据所使用的低水泥浇注料的性能，对中铝山西分公司检修厂4号焙烧炉制定了合理的烘烤曲线，提高了耐火内衬的质量，延长了内衬的使用寿命。     

Wave drift force in a two-layer fluid of finite depth

Based on the momentum and energy conservation principles, a compact calculation formula is analytically derived for the wave-drift force on a 2-D body floating in a two-layer fluid of finite depth. In a two-layer fluid, two different wave modes (the surface-wave mode with longer wavelength and the internal-wave mode with shorter wavelength) exist not only in the incident wave but also in the body-scattered wave, and these wave characteristics are properly incorporated in the obtained formula. It is noted that, unlike the single-layer case, the wave-drift force can be negative in the incident wave of surface-wave mode, if the transmitted wave with internal-wave mode is large. Numerical computations are implemented for a Lewis-form body by means of the boundary-integral-equation method with Green’s function for the two-layer fluid problem. The effects of density ratio, interface position, and body motions on the wave-drift force are studied, and some important features are found for two-layer fluids.     

叠前深度偏移中的旅行时并行计算技术

旅行时计算技术是基于波动方程叠前深度偏移方法的核心内容，射线跟踪的数值计算精度和效率直接影响着介质成像质量和实用化。基于三维射线跟踪的微变网络方法和波前重建思路，提出一种适用于三维复杂介质地震波走时的快速算法。但它所需计算量巨大。采用并行计算技术，设计出基于“任务缓冲池”的动态负载平衡策略，在现有的分布式计算机上，实现了三维射线追踪和叠前深度偏移的并行计算。     

Failures of retrieval and comparison constrain change detection in natural scenes.

In a change detection paradigm, a target object in a natural scene either rotated in depth, was replaced by another object token, or remained the same. Change detection performance was reliably higher when a target postcue allowed participants to restrict retrieval and comparison processes to the target object (Experiment 1). Change detection performance remained excellent when the target object was not attended at change (Experiment 2) and when a concurrent verbal working memory load minimized the possibility of verbal encoding. (Experiment 3). Together, these data demonstrate that visual representations accumulate in memory from attended objects as the eyes and attention are oriented within a scene and that change blindness derives, at least in part, from retrieval and comparison failure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

三维合成炮叠前深度偏移

对国际上标准的SEG/EAEG模型进行了三维合成炮叠前偏移研究。与三维单炮叠前深度偏移不同 ,三维合成炮叠前偏移有一个叠前数据的合成过程 ,由于合成后数据量大大减少 ,所以合成炮偏移的计算量要比单炮偏移小得多。阐述了三维合成炮叠前偏移的实现过程 ,给出了相应公式。对SEG/EAEG盐丘模型的一个数据集进行了MPI并行计算 ,取得了良好的成像效果。所作的较多计算表明了三维合成炮叠前偏移的正确性和有效性 ,这为野外实际数据的三维叠前深度偏移提供了另一条有效途径。     

Effects of processing conditions on the curing of a vinyl ester resin

The effects of temperature, initiator, and accelerator levels on the curing of an epoxy bisphenol‐A vinyl ester resin Derakane® 411‐45 (formulated with styrene) were investigated by gel‐time and exotherm‐peak measurements on bulk samples. It was observed that the gel time was reduced as the initiator or accelerator ratio increased. Except at higher contents of the accelerator, a small kinetic plateau was seen in the gel curve and a shift of the maximum exotherm toward high temperatures in the DSC curves. This was explained by the dual role played by the accelerator species. A regression analysis of all gel‐time data showed a dependence of 3/2 order in the accelerator and first order in the initiator concentrations. Thus, for this polymerization initiation system, the gel time can be predicted for any initiator and cobalt levels and at any temperature within the ranges studied. The effect of the initiator on the unreacted styrene and vinyl ester was also examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1146–1154, 2002; DOI 10.1002/app.10403     

考虑渗流力的基坑涌砂分析

本文根据基坑防渗帷幕周围的地下水渗流特征，分析了渗流力对基坑流砂的影响，提出了按涌砂安全系数进行防渗帷幕埋入深度计算的方法。