金属表面环氧漆漆膜拉伸剪切强度的测定

借鉴国标胶粘剂拉伸剪切强度测定方法测定了阳极、阴极环氧电泳漆与环氧涂料在底材为铝合金及钢材上漆膜的拉伸剪切强度，在铝件及钢铁件表面上阳极电泳漆漆膜的拉伸剪切强度为11．60MPa及17．91MPa，阴极电泳漆漆膜分别为17．60MPa及23．20MPa，喷涂环氧漆膜为7．93MPa 及13．40MPa，并介绍了测定试验中的实际操作经验和技术细节。     

硝铵装置降膜蒸发存在问题与改进措施

对我公司硝铵装置降膜蒸发工序存在的问题进行分析 ,并通过技术改进 ,使干燥洗涤液全部返回系统 ,造粒塔粘塔问题得到缓解 ,取得可观的经济效益和环保效益     

Energy flux characteristics of seismic waves at the interface between soil layers with different saturations

Based on the multiphase poroelasticity theory describing the propagation of waves in the unsaturated fluid-saturated porous medium, the reflection and transmission coefficients of the seismic waves at the interface between soil layers with different saturations are obtained. Our unsaturated model consists of a deformable skeleton in which two compressible and viscous fluids (i.e., water and gas) flow in the interstices. Three compressional waves (i.e., P1, P2, and P3 waves) and one shear (i.e., S wave) wave exist in the unsaturated soils. The expressions for the energy ratios of the various reflected and transmitted waves at the interface during the transmission and reflection processes are presented in explicit forms accordingly. At last, numerical computations are performed and the results obtained are respectively depicted graphically. The variation of the energy ratios with the incident angle, wave frequency and saturation degrees of the upper and lower soil layers is illustrated in detail. The calculation results show that the allocation of incident seismic waves at the interface is influenced not only by the angle and frequency of the incident seismic waves, but also by the saturations of the upper and lower soil layers. It is also verified that, at the interface, the sum of energy ratios of the reflected and transmitted waves is approximately equal to unity as was expected. This study is of importance to several fields such as geotechnical engineering, seismology, and geophysics.     

Effect of polycarboxylate-type superplasticizer on the paste fluidity based on the water film thickness of flocs

The excess water film theory and the properties of flocs are integrated to examine the effect of the polycarboxylate-type superplasticizer on the paste fluidity.The theory states that excess water can surround the flocs rather than the particles and that the cell consists of a floc and a superficial water film.Experiments on limestone powder pastes were conducted to verify the theory.The superplasticizer dosage(sp%)and the water–powder ratio by volume(Vw/Vp)were systematically varied.A sedimentation balance method was used to measure the size distribution of the flocs in the limestone powder pastes.The water film thickness(WFT)of flocs was then calculated and shown to determine the paste fluidity.Based on this WFT of flocs,the effect of the sp on the paste fluidity was determined and then compared with the effect of water.     

锅炉过热器/再热器管道热流密度的评估方法

通过建立数值模型进行编程计算,分析了锅炉过热器/再热器管道在不同的管道几何尺寸、烟气温度、蒸汽流量和温度下,各个界面热流密度的变化情况。通过回归分析得到了热流密度与管道内壁侧氧化层厚度和运行时间的关系表达式,即热流密度的评估关系式。     

26型单功能轴冷温挤压工艺与模具设计

26型单功能轴为偏心凸轮轴,精度高,加工难度大。阐述了采用冷温挤压代替切削加工的优点,对偏心轴零件进行了分析,制定了合理的工艺路线并据此设计出了成形模具。经实际生产证明,所做的工艺理论分析正确可行,模具设计合理,使材料利用率和生产效率提高。     

改性高岭土上甲苯的选择性硝化(IV)

应用Ｍｅｎｋｅ条件，在改性高岭土固体酸催化下，甲苯能被浓硝酸对位选择性硝化，表现在对邻硝化产物比例达到１．５。     

环保高性能防腐涂料驱动未来市场

介绍了防腐涂料的新品种和防腐体系的选择,指出了我国防腐涂料的发展趋势。     

一种矩形微米流道的加工与流量测定

介绍了一种比较成熟的矩形微米流道(微槽道)加工工艺,利用厚胶光刻工艺在硅片上制备胶模板,进而在该模板上用高分子聚合物PDMS(Polydimethylsiloxane,聚二甲基硅氧烷)制作了微米量级的微槽道(高、宽范围20~100μm),对制备的微槽道的几何精确度进行了20×100倍放大显微观测,对其流量特性进行了实验测定.实验结果与泊肃叶理论公式(NS方程的管流表达式)相对比,可以看到在微米量级的矩形微流道中,泊肃叶公式仍然适用.     

A coaxial pulsed plasma thruster using chemical propellants

Pulsed plasma thrusters (PPTs) have the advantages of mechanical simplicity and robustness compared to other electric propulsion systems. However the thrust power ratio of PPTs is lower than that of other electric propulsion systems. To enhance the thrust performance of the PPT, we propose to use several combustible solid chemicals as coaxial PPT propellants to replace Teflon^® (Polytetrafluoroethylene: PTFE). With the design, the force obtained thermodynamically is expected to augment the PPT thrust power ratio with the help of the chemical energy contained in the propellants. As a result, the thrust power ratio is increased using hydroxyl-terminated polybutadiene-ammonium perchlorate (HTPB-AP)-based propellants compared to the case of ordinary Teflon. The discharge current and voltage waveform does not change even when the propellant is changed. These findings could indicate that the impulse bits by gasdynamic contribution are lager in the case of chemical solid propellants than in the case of Teflon.