用LG55冷轧管机轧制小直径不锈钢管孔型改进

介绍了ＬＧ５５冷轧管机使用Φ７～３２ｍｍ、Φ５０～３２ｍｍ孔型轧制小直径不锈钢管的工艺特点。试验表明，两种孔型可行，且Φ５７～３２ｍｍ孔型的综合使用效果更好。     

磁性材料产业现状与展望

介绍磁性材料的主要品种，如永磁体、软磁体和磁记录介质材料的行业现状及技术进步。     

火焰原子吸收光谱法测定高纯石英粉中痕量钙

系统地研究了用空气——乙炔火焰原子吸收光谱分析法测定高纯石英粉中钙的最佳条件，建立了14％的乙醇作为增感剂，在2％盐酸介质中，0．4％ LaCl3溶液作为释放剂，用塞曼火焰原子吸收法测定的可行性方案，探讨了共存元素对钙的干扰及其消除。方法操作简便快速，干扰少，方法相对标准偏差小于3％，适用于日常分析石英粉中的杂质。     

Development of the meshless finite volume particle method with exact and efficient calculation of interparticle area

The Finite Volume Particle Method (FVPM) is a meshless method based on a definition of interparticle area which is closely analogous to cell face area in the classical finite volume method. In previous work, the interparticle area has been computed by numerical integration, which is a source of error and is extremely expensive. We show that if the particle weight or kernel function is defined as a discontinuous top-hat function, the particle interaction vectors may be evaluated exactly and efficiently. The new formulation reduces overall computational time by a factor between 6.4 and 8.2. In numerical experiments on a viscous flow with an analytical solution, the method converges under all conditions. Significantly, in contrast with standard FVPM and SPH, error depends on particle size but not on particle overlap (as long as the computational domain is completely covered by particles). The new method is shown to be superior to standard FVPM for shock tube flow and inviscid steady transonic flow. In benchmarking on a viscous multiphase flow application, FVPM with exact interparticle area is shown to be competitive with a mesh-based volume-of-fluid solver in terms of computational time required to resolve the structure of an interface.     

Development of high‐definition aqueous polyvinylpyrrolidone photoresists for cathode ray tubes

Aqueous photoresists that are capable of higher resolutions than are currently employed by the cathode ray tube (CRT) industry were developed by combining photoactivators, which activate at shorter UV wavelengths with polyvinylpyrrolidone (PVP). Two photoactivators were synthesized: 4,4′‐diazido‐2,2′‐biphenyl disodium disulfonate (DABP), which has a maximum absorbance at 264 nm, and 4,4′‐diazido‐2,2′‐biphenylethane disodium disulfonate (DABPE), which has a maximum absorbance at 258 nm. The PVP/DABP and PVP/DABPE photoresists successfully imaged a pattern with resolution as small as 4.4 μm with photoactivator concentrations greater than 20% of the PVP concentration. Addition of silane and emulgen greatly improved the performance of the photoresists with more uniform coatings of thicknesses of up to 1.4 μm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1637–1644, 2006     

Φ10007/00有压三产品重介旋流器结构参数优选与分选效果

辛置选煤厂针对原煤煤质变化后的特点 ,采用有压给料三产品重介旋流器为核心的高效选煤工艺系统分选 5 0～ 0mm原煤 ;对旋流器一段及二段中心管的直径和插入深度、二段底流口的直径等进行了优化调整 ,同时调整了介质泵的工作频率及悬浮液密度等参数 ,取得了分选效率高、产品质量稳定等显著效果     

换热器管板厚度的快速计算

在化工生产中，换热器设备是应用最广泛的一种设备，且占主导地位。而在换热器设计过程中，管板厚度设计计算比较复杂。本文的特点是在满足GB151—1999《管壳式换热器》标准要求的前提下，介绍一种快速简便估算管板厚度的计算公式，从而达到快速确定管板厚度的目的。     

高效防腐中温磷化液LC-1的制备及性能

制备了一种含Zn2+、Mn2+、N i2+三系离子的LC-1磷化液,通过硫酸铜点滴、氯化钠浸蚀、SEM等手段对磷化膜进行了测试,测定了磷化温度、磷化时间对膜层耐蚀性的影响。结果表明,在磷化温度大于65℃,磷化时间大于10 m in的条件下,所形成的磷化膜结晶均匀、致密、黑褐色,耐蚀性良好。LC-1三系磷化液可适用于大批量钢铁工件的磷化生产。     

重介洗煤密度自控系统研究

目的：本文介绍了PLC在洗煤厂的介质密度控制中的应用,针对介质密度变化规律性不强,大滞后等特点作出调整。方法：采用VB编程语言结合专家算法的方针,提出了一个解决方案,提高了控制密度精度。结果：使物料浓度配比更加合理,趋势变化更容易让现场人员接受。结论：提高了产煤精度及生产效率,节约了能源的同时为洗煤厂创造更大的经济回报。     

Analysis of junction temperatures in high-power GaN-based LEDs

We presented the analysis of the incomplete conduction in bonding medium in high power GaN-based light-emitting diode (LED) packages. A numerical study was carried out with parametric model to understand the junction temperature variation due to bonding medium defects. Transient thermal measurement was performed to evaluate LED’s junction temperature. Thermal resistance from chip to lead frame was 20 K/W in our sample LED. It was suggested that only 60% of the surface area of the bonding medium was involved...