种子法制备聚合物乳液技术的进展

从建筑乳液的生产现状、自生种子法与外加种子法的区别、种子乳液的特点及外加种子法生产的乳液特性等方面介绍了种子法制备乳液技术的进展。     

The effect of radical desorption on the particle size distribution in vinyl acetate emulsion polymerization

The effect of free radical desorption is studied by using a mathematical model of particle size distribution in continuous emulsion polymerization. By comparing the theoretical prediction with experimental data, the value of D_o for the vinyl acetate (VAc) system is best chosen as 0.19 × 10^?7 cm²/h. The effect of radical desorption as well as mean residence time on the absolute particle size distribution, total concentration of polymer particles, conversion, and average number of radicals per polymer particle are analyzed by the model proposed.     

Effect of particle size on the surface oxidation and flotation behavior of galena particles in lime system

ABSTRACT

In this research, the effect of particle size on the surface oxidation and flotation behavior of galena in the lime system was studied. Coarse (?0.074 + 0.038 mm), intermediate (?0.038 + 0.025 mm) and fine (?0.025 mm) galena particles were used in the experiment. The dissolution tests, flotation tests, and sorption tests were accomplished. Through further analysis by XPS, the effect of particle size and lime was observed. The decrease of mineral particle sizes increased the adsorption ratio of collector and the dissolution of galena, while the hydrophilic product OH^?/Ca(OH)⁺ produced by dissolution occupied the dominant position, which led to the minerals hydrophilic.     

Formation Mechanisms of Platelet Sr3Ti2O7 Crystals Synthesized by the Molten Salt Synthesis Method

The molten salt synthesis (MSS) method is utilized to synthesize the anisotropic platelet Sr₃Ti₂O₇ (S3T2) single-crystal particles. The aim of this study is to identify the essence of platelet Sr₃Ti₂O₇ crystal growth and guide the synthesis of anisotropic platelet SrTiO₃ crystals as well as various technologically important materials. Based on the results of X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy, the formation mechanism of platelet Sr₃Ti₂O₇ crystals conforms to a nucleation–structure rearrangement–dissolution–diffusion in situ epitaxial growth mechanism model. First, SrCO₃ reacts with TiO₂ to form submicrometer SrTiO₃ nuclei. Then, most of the nuclei surrounded by salt ions aggregate and rearrange to form a large SrTiO₃ matrix. The structural rearrangement and the subsequent in situ epitaxial growth processes control the morphology, composition, and size of the final Sr₃Ti₂O₇ crystals. In the synthesis process, the conversion between SrTiO₃ and Sr₃Ti₂O₇ is as follows: and the crystallographic orientation relationship between Sr₃Ti₂O₇ and SrTiO₃ in the interface is (100)_S3T2//{100}_ST, (010)_S3T2//{010}_ST, and (001)_S3T2//{001}_ST.     

熔融石英耐火材料

阐述了熔融石英耐火材料的主要性能与应用领域。     

温度对工业汽轮机运行的影响

由于温度的变化，而引起机组热应力的变化，这是工业汽轮机运行中最主要的变化，它对机组的安全和运行影响非常大。     

山梨醇类聚丙烯成核剂的开发与应用研究进展

综述了山梨醇类聚丙烯成核剂产品在国内外的开发进展，介绍了该类成核剂在聚丙烯中的应用和效果，及其作用机理。     

Polyaniline for corrosion prevention of mild steel coupled with copper

Polyaniline emeraldine base/epoxy resin (EB/ER) coating was investigated for corrosion protection of mild steel coupled with copper in 3.5% NaCl solution. EB/ER coating with 5-10 wt% EB had long-term corrosion resistance on both uncoupled steel and copper due to the passivation effect of EB on the metal surfaces. During the 150 immersion days, the impedance at 0.1 Hz for the coating increased in the first 1-40 days and subsequently remained constant above 10⁹ Ω cm², whereas that for pure ER coating fell below 10⁶ Ω cm² after only 30 or 40 days. Immersion tests on coated steel-copper galvanic couple showed that EB/ER coating offered 100 times more protection than ER coating against steel dissolution and coating delamination on copper, which was mainly attributed to the passive metal oxide films formed by EB blocking both the anodic and cathodic reactions. Salt spray tests showed that 100 μm EB/ER coating protected steel-copper couple for at least 2000 h.     

Vapor-liquid equilibria in the argon-methane system

Vapor-liquid equilibrium compositions have been measured for the argon-methane system at 115.2°, 123.4° and 137.1°K, by means of a forced-recirculation apparatus. A modified Redlich-Kwong equation of state with the incorporation of a binary interaction constant has been successfully employed to represent the data. Liquid activity coefficients have been evaluated and correlated.     

Decentralized weighted control for a class of large‐scale systems with multi‐modes

In this paper, the control synthesis problem for a class of large‐scale systems with multi‐modes that are called large‐scale switched systems is addressed. By introducing the concept of decentralized switching signal and the relevant decentralized average dwell time, the asymptotic stability and weighted ?₂ gain performance are investigated. It should be noted that the decentralized switching covers general switching cases for large‐scale switched systems, namely, it admits both time‐dependent switching signal and arbitrary switching signal blended in the decentralized switching. Then, on the basis of the analysis results, the decentralized weighted control scheme including state feedback controller gains and switching signals is studied. Several design algorithms are proposed to meet different controller design problems. Finally, numerical examples are provided to illustrate theoretical findings within this paper. Copyright © 2013 John Wiley & Sons, Ltd.