Improvement of Microwave Loss Tangent and Tunability of Ba0.55Sr0.45TiO3/MgO Composites Using the Heterogeneous Precipitation Method

Ba_0.55Sr_0.45TiO₃/MgO composites were successfully prepared by the heterogeneous precipitation method and their structural, surface morphological, tunable properties, and dielectric properties at microwave frequency were systemically investigated. Compared with the sample prepared by the traditional solid-state method, the sample prepared by the heterogeneous precipitation method exhibits a smaller grain size, more uniform microstructure, higher tunability, and lower microwave loss, and these properties are very beneficial to the development of the microwave tunable devices application. Moreover, the effects of La₂O₃ doping on the dielectric and tunable properties of BST/MgO composites are investigated. The result shows that the La³⁺-doped sample has higher tunability and lower microwave loss than the undoped one.     

Shear creep resistance of styrene–isoprene–styrene (SIS)‐based hot‐melt pressure‐sensitive adhesives

The effects of the properties of substrates and tackifier on the shear creep of SIS‐based HMPSAs were investigated. The holding power (t_b) and shear adhesion failure temperature (SAFT) were measured. The relationship between the complex viscosity and the holding power was examined. The holding power and SAFT values of the triblock SIS blends were higher than those of the diblock‐containing SIS blends, perhaps because blends using triblock SIS have higher crossover temperature and complex viscosity than those using diblock‐containing SIS. Higher levels of aromatic resin‐modified aliphatic tackifier and rosin ester were found to decrease the holding power of the HMPSAs. This maybe due to the fact that rosin ester and aromatic‐modified aliphatic resin are compatible with both the ends and midblocks of SIS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 825–831, 2006     

High PVC film‐forming composite latex particles via miniemulsification,part 1: Preparation

Miniemulsification technology was used to encapsulate TiO₂ particles inside a styrene/n‐butyl acrylate copolymer with high loading levels (11 to 70% PVC (pigment volume concentration)). In this approach, a St/BA copolymer dissolved in toluene in the presence of a costabilizer (hexadecane) was mixed with a dispersion of TiO₂ particles in toluene and sonified, and then emulsified in an aqueous surfactant solution by sonification. The effect of sonification time on both the dispersibility of the TiO₂ particles in the presence of the copolymer and hexadecane and on the encapsulated particle size was investigated. Particle size analysis by dynamic light scattering showed that these composite latexes are quite stable. It was also found that as the TiO₂ loading increased from 11 to 43% PVC, the particle size of the TiO₂ dispersion decreased while the polymer‐encapsulated TiO₂ particle size increased. The effect of surfactant concentration (sodium lauryl sulfate, SLS) on the encapsulated particle size was investigated using four different SLS concentrations in the 11% PVC system. The results showed that as the SLS concentration increased the particle size decreased, as expected. Also it was found that the minimum surfactant concentration that gives stable encapsulated TiO₂ particles is above 10 mM SLS. The role of HD in the recipe was studied for an artificial latex containing no TiO₂ and one prepared at 11% PVC, in terms of particle size before and after solvent stripping, and its effect on the T_g. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4504–4516, 2006     

FCS-DCS两种控制系统比较

当前现场总线控制系统(FCS)是控制领域中的热点,是在集散控制系统(DCS)的基础上产生的,二者是继承和发展的关系。DCS已走过了近30年的历程,广泛应用于化工、石油、电力、水泥等工业过程,基本上满足了大、中、小控制工程的需求。传统的DCS系统由各种工作站通过     

双电层电容器用沥青焦基活性炭的制备工艺条件对其孔结构及电化学性能的影响

以沥青焦为原料，KOH为活化剂在不同的工艺条件下制备了双层电容器用活性炭电极材料。分别考察了活化剂用量、活化时间、以及加入Cu、Ni催化活化等工艺条件对活性炭孔结构及作为双电层电容器电极的电化学性能的影响。结果表明：在实验范围内增加KOH用量及活化时间，活性炭的比表面积和比电容增加，比电容最高达到247F／g。添加Cu、Ni催化活化后活性炭的比表面积及比电容增加，高功率放电性能明显改善。     

2,6-二氯-4-三氟甲基苯胺制备新工艺

以对硝基甲苯为原料，经溴化、氟置换、加氢还原得4-三氟甲基苯胺，收率59．8％，纯度98．66％。然后，用硫酰氯作为氯化试剂，进行苯环上的氯化反应，制得氟虫腈关键中间体2,6-二氯-4-三氟甲基苯胺。收率83.9％，产品熔点34℃-35℃，纯度97．95％。对各步反应的影响因素进行了探讨。     

抗菌灭病毒涂料的研制及表征

在评价多种杀菌剂的抗病毒性能的基础上,筛选出杀菌和抗病毒性能均优异的功能助剂三氯苯基马来酰亚胺,用以研制成一种杀菌灭病毒功能内墙涂料。     

工业废渣在复合无光乳浊釉中的应用

以废瓷粉、废玻璃粉、粉煤灰等工业废渣为主要原料．添加其它常用的陶瓷原料，成功研制出乳白色、彩色(添加色料)、费色(以粉煤灰着色)三个系列无光乳浊釉。这些釉的烧成温度为1180℃左右，烧成气氛为氧化气氛．它们具有废渣用量大(废渣总用量40-50％)、熔块用量低(0～12％)、成本低等特点。     

工业碳酸钡生产过程危险性分析

阐述了工业碳酸钡的生产方法。在碳酸化法生产工业碳酸钡过程中，存在着火灾、爆炸、中毒、触电、灼烫等危险因素。分析了工业碳酸钡生产的原料粉碎工段、雷蒙工段、粗钡工段、化钡工段、石灰窑工段、压缩机工段、碳化工段、过滤工段、烘干包装工段中存在的危险性，并制定了相应的预防及处理措施。指出安全措施应与主体装置同时设计、同时施工、同时投用。     

4H-SiC无线无源高温压力传感器设计

高温压力传感器研制的主要目的是解决高温恶劣环境下的压力测量问题,SiC是制造高温压力传感器的理想材料,结合薄膜技术与陶瓷厚膜技术,提出了一种新型的4H-SiC无线无源电容式高温压力传感器设计方案。应用Ansys有限元分析软件进行仿真,600℃时灵敏度为2.65 MHz/bar,说明传感器在高温下具有较高的灵敏度,对制备过程中的关键工艺——SiC深刻蚀进行了验证,刻蚀深度达到124μm,满足传感器制备要求。