Characteristics of electrical responsive chitosan/polyallylamine interpenetrating polymer network hydrogel

An interpenetrating polymer network (IPN) hydrogel composed of chitosan and polyallylamine exhibited electric‐sensitive behavior. The chitosan/polyallylamine IPN hydrogel was synthesized by radical polymerization using 2,2‐dimethoxy‐2‐phenylacetophenone (DMPAP) and methylene bisacrylicamide (MBAAm) as initiator and crosslinker, respectively. The swelling behavior of the IPN was studied by immersion of the gel samples in aqueous NaCl solutions at various concentrations and pHs. The swelling ratio decreased with increasing concentration and pH of electrolyte solution. The stimuli response of the IPN hydrogel in electric fields was also investigated. When a swollen the IPN was placed between a pair of electrodes, the IPN exhibited bending behavior in response to the applied electric field. The IPN also showed stepwise bending behavior depending on the electric stimulus. In addition, thermal properties of the IPN were investigated by differential scanning calorimetry (DSC) and dielectric analysis (DEA). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2290–2295, 2002     

炭黑－环氧树脂导电复合材料的研究

本文研究了炭黑－环氧树脂复合材料的制备工艺及炭黑填充率对材料电阻率的影响。实验结果表明，加入表面活性剂，明显改善了炭黑在环氧树脂中分布的均匀性。炭黑－环氧树脂材料具有明显的渗流效应，正温度系数效应即ＰＴＣ效应，非线性伏安特性和电磁波屏蔽效应。     

PVC／PU合金的制备与研究

叙述了选择混炼型聚氨酯(PU)与分子量适中的Ⅱ型聚氯乙烯(PVC)树脂制备PVC/PU合金的过程,讨论了PVC/PU共混比、填充剂、硫化体系、共混工艺等因素对PVC/PU合金性能的影响。结果表明:选择PVC/PU=60/40(质量比),硫化剂TD15份,白炭黑30份,混炼温度140—160℃,可制得性能优良的PVC/PU合金。动态力学性能实验显示了PVC/PU合金有较好的相容性。     

Lower Bounds for Eigenvalues of Elliptic Operators: By Nonconforming Finite Element Methods

The paper is to introduce a new systematic method that can produce lower bounds for eigenvalues. The main idea is to use nonconforming finite element methods. The conclusion is that if local approximation properties of nonconforming finite element spaces are better than total errors (sums of global approximation errors and consistency errors) of nonconforming finite element methods, corresponding methods will produce lower bounds for eigenvalues. More precisely, under three conditions on continuity and approximation properties of nonconforming finite element spaces we analyze abstract error estimates of approximate eigenvalues and eigenfunctions. Subsequently, we propose one more condition and prove that it is sufficient to guarantee nonconforming finite element methods to produce lower bounds for eigenvalues of symmetric elliptic operators. We show that this condition hold for most low-order nonconforming finite elements in literature. In addition, this condition provides a guidance to modify known nonconforming elements in literature and to propose new nonconforming elements. In fact, we enrich locally the Crouzeix-Raviart element such that the new element satisfies the condition; we also propose a new nonconforming element for second order elliptic operators and prove that it will yield lower bounds for eigenvalues. Finally, we prove the saturation condition for most nonconforming elements.     

新型呋咱(氧化呋咱)类炸药爆轰参数的理论计算

以3,4-二(氨基呋咱基)氧化呋咱(BAFF)为结构单元设计了一类新型呋咱(氧化呋咱)类炸药分子.运用预测炸药分解产物的BW法则、计算爆速的Rothsteine方法和计算C-J压力的库珀方法等对该类炸药的爆炸参数进行了理论计算,并与HMX等炸药的爆炸参数进行了比较.结果表明,该类炸药的密度大,爆速和爆压介于TATB和HMX之间,是一类新型高能量密度材料化合物.由于该类炸药分子中含呋咱环具有芳香性,预测其分子的稳定性良好.     

裂缝-溶洞型碳酸盐岩水驱油机理研究现状

裂缝-溶洞型碳酸盐岩的油水两相流动形态复杂,本文针对此类油藏水驱油机理研究做了大量的文献调研,阐述了此类油藏的水驱油机理研究现状,并提出新的试验研究方法和建议,以进一步加深对这类油藏驱油理论的认识。     

Synthesis and characterization of poly(ϵ‐caprolactone)‐b‐poly(ethylene glycol) block copolymers prepared by a salicylaldimine‐aluminum complex

A series of poly(?‐caprolactone)‐b‐poly(ethylene glycol) (PCL‐b‐PEG) block copolymers with different molecular weights were synthesized with a salicylaldimine‐aluminum complex in the presence of monomethoxy poly(ethylene glycol). The block copolymers were characterized by ¹H NMR, GPC, WAXD, and DSC. The ¹H NMR and GPC results verify the block structure and narrow molecular weight distribution of the block copolymers. WAXD and DSC results show that crystallization behavior of the block copolymers varies with the composition. When the PCL block is extremely short, only the PEG block is crystallizable. With further increase in the length of the PCL block, both blocks can crystallize. The PCL crystallizes prior to the PEG block and has a stronger suppression effect on crystallization of the PEG block, while the PEG block only exerts a relatively weak adverse effect on crystallization of the PCL block. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

氧化锆超细粉体的制造方法及应用

介绍了氧化锆超细粉体的性能、应用及制造方法。     

地层主曲率在研究储层裂缝发育中的应用

曲面曲率的几何意义可以反映曲面一点邻近区域的具体形态和变形特征,因而可以用主曲率法来评价和预测油气储层裂缝分布和发育程度,应用这种方法对泌阳深凹陷中心安棚鼻状构造带进行了评价。研究结果表明,采用主曲率法预测的结果与地质解释、钻井和测井资料吻合较好,具有很好的应用前景。     

CO2混合物热物性在CCS研究中的作用:实验数据、理论模型和典型应用

二氧化碳捕集与封存（CCS）各工艺过程的设计、运行都依赖于对CO₂及其混合物热物理性质的深入理解。同时，CCS的规模化发展和商业化进程，对CO₂混合物及其热物性的准确性提出了更高的要求。本文从实验数据、理论模型和典型应用3个方面综述了CO₂及其混合物热物性的发展现状，并尝试对发展趋势进行归纳。在实验研究方面，CO₂混合体系的研究进展视组分不同，差异较大，其中CO₂-N₂、CO₂-CH₄、CO₂-H₂O和CO₂-H₂二元体系已形成较完善的物性数据库，而CO₂-NH₃、CO₂-NO _x 和CO₂-CO体系的物性数据还比较欠缺；在物性估算方面，面向CCS的物性估算模型研究自2008年开始活跃，基于不同理论构架，目前已逐步形成面向CCS的多元化的物性估算体系。物性研究在CCS中的应用主要体现在物性是支撑CCS过程研究的基础，其不准确性在过程模拟或计算中会被“放大”，从而影响过程评估的准确性，本文从物性在循环构建和能效分析中的作用以及CO₂水合物的形成3个方面入手做了说明。文章最后对面向CCS的物性研究趋势进行了梳理，对分子模拟技术、通用性强的物性估算模型和物性在过程设计和循环分析中的角色进行了展望。