Preparation and characterization of polyurethane microcapsules containing n‐octadecane with styrene‐maleic anhydride as a surfactant by interfacial polycondensation

A series of polyurethane microcapsules containing a phase change material (PCM) of n‐octadecane was successfully synthesized by an interfacial polymerization in aqueous styrene‐maleic anhydride (SMA) dispersion with diethylene triamine (DETA) as a chain extender reacting with toluene‐2,4‐diisocyanate (TDI). The average diameter of microPCMs is in the range of 5–10 μm under the stirring speed of 3000–4000 rpm. Optical and SEM morphologies of microPCMs had ensured that the shell was regularly fabricated with the influence of SMA. FTIR results confirmed that the shell material was polyurethane and the SMA chains associated on core material reacted with TDI forming a part of shell material. The shell thickness was decreasing in the range of 0.31–0.55 μm with the molar ratio of DETA/TDI from 0.84 to 1.35 and the weight of core material increasing from 40 to 80% (wt %). By controlling the weight ratio of PCM as 40, 50, 60, 70, and 80% in microPCMs, it was found using DSC that the T_m and T_c of microPCMs were in the range of 29.8–31.0^oC and 21.1–22.0°C and an obvious phase change had been achieved nearly the same temperature range of that of PCM. The results from release curves of microPCM samples prepared by 1.4, 1.7, and 2.0 g of SMA indicated the release properties were affected by the amount of the dispersant, which attributed to the emulsion effect and shell polymerization structure. The above results suggest that the shell structure of microPCMs can be controlled and the properties of microPCMs determined by shell will perform proper practical usage. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4996–5006, 2006     

直接斜率波前复原算法的控制效果分析

建立自适应光学系统功率谱抑制函数的概念，分析了采用直接斜率波前复原算法的自适应当光学系统的控制效果，理论分析与６１单元自适应光学系统上的实验结果表明，直接斜率波前复原算法将导致控制效果下降。     

用偏微分方程构造过渡面

用偏微分方程的构造曲面是一种新兴的方法，本文借若干算例说明如何用偏微分方程构造两已知曲面之间的过渡面。论文着重讨论用四阶方程构造一阶连续的过渡面。     

月光之丽、变彩之奇的月光石

根据所藏月光石的光薄片鉴定研究，阐述了月光石的美学特征和产生原因。介绍了月光石的产出特征和相应的月光石文化，同时介绍了我国关于“和氏壁”属性与月光石关系的研究历史及现状。     

钛型气保护药芯焊丝熔滴过渡与气孔(压坑)的关系

采用改变药芯组成物配比、平板堆焊和电弧物理观察等试验方法，研究钛型气保护药芯焊丝熔滴过渡与气孔（压坑）敏感性间的关系。结果表明，细熔滴过渡时气孔（压坑）倾向大，熔滴在电弧中吸收氢的总量是形成气孔（压坑）的主要因素；促使熔滴细化的药芯组成物具有增大气孔（压坑）倾向的作用；焊接工艺参数中，焊接电流、电弧电压对熔滴过渡形态-气孔（压坑）倾向影响的规律性，基本遵循了“熔滴过渡形态对气孔的影响理论”所揭示的机理。     

高铬铸铁中铌碳化物的辨认

介绍了用背散射象法、彩色金相法和扫描电镜分析区别铬碳化物和铌碳化物。     

工艺参数对电磁铸造铝板坯温度场的影响

采用数值方法模拟电磁铸造过程的温度场，详细讨论了各种工艺参数，如宽厚比，浇注温度，铸造速度，冷却水量，喷水位置，喷水孔分布，感应热等对铝板坯凝固过程和温度场分布的影响规律，为电磁铸造工艺参数设计提供可靠依据。     

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.     

电除尘器分电场灰密度变化规律及粉煤灰密度与成份的关系

本文介绍粉煤灰经电除尘器分离后所得分电场灰密度沿电场方向的变化规律及影响因素，并阐述了粉煤灰密度与成份之间的关系。     

分析计算思维与计算机方法

计算机思维与计算机方法论都有着自己的特点,可相互促进并互补。例如,计算机思维可以为计算机方法论提供参考依据,同时通过计算机方法论的学习、研究,更更好培养出计算机思维。两者各具优势,是值得相互学习的。本文分析了计算思维与方法论的相关概念,同时对两者关系进行简单阐述。