柴油机缸套漏水检验方法研究

本文概述柴油机漏水的检验方法,详细介绍作者研制的柴油机漏水检漏胶带。使用该方法可在柴油机动、静态下实现缸套漏水检验,它弥补了水压法不能动态漏水检验的缺陷,具有一定推广价值。     

Rheological and mechanical behavior of non-spherical poly(lactic acid) particles embedded poly(butylene adipate-co-terephthalate) blend

In this study, the poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate)(PBAT) blend is investigated to improve rheological and mechanical performances of PBAT based on rheological, mechanical, and thermal behavior analyses. The multi-step mixing method is developed to fabricate the blend with non-spherical morphology. In the multi-step mixing method, blends with a wide composition range (25/75–75/25) are mixed with additional PBAT at a mixing temperature between the melting temperatures of PBAT and PLA to produce the PBAT blend embedded with non-spherical PLA particles (10 wt%). The embedding of non-spherical PLA particles in PBAT increases the resistance against deformation, resulting in strain hardening behavior and an increase in the yield strength as well as the tear resistance of the PBAT. The presence of stiff PLA particles enhances the crystallization behavior of PBAT, meaning that polymer chains may interpenetrate. The findings of this study suggest that the multi-step mixing method is beneficial for embedding non-spherical PLA particles into a PBAT matrix, which in turn facilitates the maintenance of good interfacial adhesion to increase the melt strength, yield strength, and tear resistance.     

水基流延法制备多层ZnO压敏电阻器的研究进展

介绍了水基流延法制备多层ZnO压敏电阻器的现状和重要性.分析了粘合剂、分散剂及浆料流变特性等对水基流延的影响,并指出了改进办法.通过比较几种水基流延用粘合剂对多层ZnO压敏电阻器电性能的影响,发现水溶性丙烯酸聚合物是最好的.随着水系粘合剂性能的提高,水基流延制备的多层压敏电阻(MLV)的电性能也得到提高,再加上它具有绿...     

铁氧体基片流延成型工艺的研究进展

介绍了铁氧体基片的研究现状及其流延成型工艺原理,重点分析了铁氧体粉体表面性质、浆料的稳定性以及不同流延体系的干燥机理,并对铁氧体基片流延成型的发展趋势进行了展望.     

Interpretation of the human skin biotribological behaviour after tape stripping

The present study deals with the modification of the human skin biotribological behaviour after tape stripping. The tape-stripping procedure consists in the sequential application and removal of adhesive tapes on the skin surface in order to remove stratum corneum (SC) layers, which electrically charges the skin surface. The skin electric charges generated by tape stripping highly change the skin friction behaviour by increasing the adhesion component of the skin friction coefficient. It has been proposed to rewrite the friction adhesion component as the sum of two terms: the first classical adhesion term depending on the intrinsic shear strength, τ₀, and the second term depending on the electric shear strength, τ_elec. The experimental results allowed to estimate a numerical value of the electric shear strength τ_elec. Moreover, a plan capacitor model with a dielectric material inside was used to modelize the experimental system. This physical model permitted to evaluate the friction electric force and the electric shear strength values to calculate the skin friction coefficient after the tape stripping. The comparison between the experimental and the theoretical value of the skin friction coefficient after the tape stripping has shown the importance of the electric charges on skin biotribological behaviour. The static electric charges produced by tape stripping on the skin surface are probably able to highly modify the interaction of formulations with the skin surface and their spreading properties. This phenomenon, generally overlooked, should be taken into consideration as it could be involved in alteration of drug absorption.     

CFD Simulation of Heat Transfer Augmentation in a Circular Tube Fitted with Alternative Axis Twisted Tape in Laminar Flow under a Constant Heat Flux

CFD simulation of heat transfer and friction factor characteristics in a circular tube fitted with twisted tape inserts in laminar flow and constant heat flux is conducted using FLUENT version 6.3.26. Plain and alternate axis twisted tape inserts with twist ratios (y = 2.93, 3.91, 4.89) and alternative angles (β = 30^°, 60^°, 90^°) have been used for the simulation. The simulated results are matched with the literature correlations for a plain tube with a discrepancy of less than ±8% for Nusselt number and ±6.25% for friction factor. The results also revealed that the heat transfer in terms of the Nusselt number increased with increases of Reynolds number, alternative angles, and decreases of twist ratio. Among the various twist ratios and alternative angles, the twist ratio of y = 2.93 and alternative angle β = 90^° offered a maximum heat transfer enhancement. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(4): 384–396, 2014; Published online 3 October 2013 in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21089     

原位反应法制备NR/二氧化硅胶膜及其性能分析

实验研究了原位生成对NR胶膜性能的影响,通过对力学性能、热老化性能、红外分析及电镜照片分析,得出原位反应可以在NR分子链中接枝二氧化硅粒子,并且在添加量为1.0%,撕裂强度为87.3721 MPa,提高了264.2%。     

车用耐高温三元乙丙橡胶密封胶垫的研制

介绍了采用三元乙丙橡胶为主要原料,制备汽车水箱用耐高温密封胶垫.结果表明,当EPDM 100(质量份);硫化剂2～4;补强剂20～50;软化剂0～10;防老剂2～4;其它助剂10～12时,该混炼胶具有优异的耐热、耐水蒸气和压缩永久变形,可满足汽车水箱、暖风机等部件的使用要求.     

抗撕型硅橡胶的配方优化

采用正交试验法考察过氧化二异丙苯(DCP)、白发黑、羟基硅油、二苯基硅二醇4个因子对硅橡胶撕裂强度的影响,分析了其差异及产生的原因,并找出了优化的硅橡胶的抗撕裂配方为:100份110-2生胶,0.6份DCP,25份白炭黑,4份羟基硅油,0.6份二苯基硅二醇.此配方得到的硅橡胶混炼胶的撕裂强度大于13 kN/m.     

不同饱和度条件下合成纤维带对昔格达土c、φ值的影响

昔格达土是攀西地区广泛分布的一种土质,其物理力学性质与普通土相比较特殊。研究合成纤维带对昔格达土性质的影响具有重要的工程应用价值。通过三轴压缩试验,测得了在含水率为23%的情况下,合成纤维带昔格达土的c、φ值比普通昔格达土的c、φ值分别提高了35.9%、33.8%;同时还测得加合成纤维昔格达土在含水率为13%、20%、23%、26%四种情况下的c、φ值及其变化规律,发现其c值在含水率为23%时最大,为112.83k Pa;φ值在含水率为26%时最小,为13.476°。该试验的研究为加筋昔格达土技术的应用提供了基础数据。