The insidious effects of failing to include design-driven correlated residuals in latent-variable covariance structure analysis.

In practice, the inclusion of correlated residuals in latent-variable models is often regarded as a statistical sleight of hand, if not an outright form of cheating. Consequently, researchers have tended to allow only as many correlated residuals in their models as are needed to obtain a good fit to the data. The current article demonstrates that this strategy leads to the underinclusion of residual correlations that are completely justified on the basis of measurement theory and research design. In many designs, the absence of such correlations will not substantially harm the fit of the model; however, failure to include them can change the meaning of the extracted latent variables and generate potentially misleading results. Recommendations include (a) returning to the full multitrait-multimethod design when measurement theory implies the existence of shared method variance and (b) abandoning the evil-but-necessary attitude toward correlated residuals when they reflect intended features of the research design. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

纳米粘土改性环氧树脂复合材料研究进展

通过对大量文献的调研,介绍了国内纳米粘土的分散方法及其改性环氧树脂复合材料的制备方法,着重对影响纳米粘土改性环氧树脂复合材料性能的主要因素进行了综述。     

改进遗传算法在输电网络规划中的应用研究

首先对输电网络规划和遗传算法进行简要论述,并确立了数学模型。为了提高遗传算法在输电网络规划中的优化性能,提出了改进自适应遗传算法(MAGA)。该方法有助于防止传统遗传算法过早收敛和走向局部最优,适应于多变量、多目标的环境,能够快速的找到全局最优。通过对实际系统的计算表明,MAGA具有可行性。最后,应用了2种不同算法进行性能比较,证实了MAGA有更强的优化性能。     

Curing mechanism of TDE-85/MeTHPA epoxy resin modified by polyurethane

Diglycidyl 4,5-epoxy tetrahydro phthalate/methyl tetrahydrophthalic anhydride （TDE-85/MeTHPA） epoxy resin modified by polyurethane （PU） was prepared with 1,4-butanediol （1,4-BDO）, trimethylol propane （TMP） and polyurethane prepolymer synthesized by polypropylene glycol and toluene diisocynate. Chemical reaction and curing mechanism of this system were discussed by incorporating the results of infra spectrum analysis. The results indicate that the epoxy polymeric network I is obtained by the curing reaction between TDE-85 and MeTHPA, while the PU polymeric network II is obtained by the chain-extended and crosslinking reaction between 1,4-BDO, TMP and polyurethane prepolymer（PUP）. The graft chemical bonds are formed between polymer networks I and II that therefore increase the degree of blend and compatibility between epoxy polymer and PU.     

种子乳液聚合法改性纳米TiO2及其表征

采用种子乳液聚合法对纳米TiO2进行表面改性，将甲基丙烯酸甲酯包覆在纳米TiO2表面，形成TiO2／PMMA复合粒子。采用FT-IR、XRD、XPS、TEM和激光粒度等分析手段对所得产物的形貌、尺寸、所携带官能团及表面元素变化情况进行了表征。结果表明复合粒子呈现核壳结构，粒子的粒径分布、团聚现象和分散性都得到改善。     

MCM-41介孔分子筛和纳米TiO2/MCM-41的合成与结构表征

以工业水玻璃为硅源,表面活性剂十六烷基三甲基溴化铵为结构模板剂,利用室温晶化法合成出MCM-41介孔分子筛,并以钛酸丁酯为前驱体,通过溶胶凝胶法及液相沉积法对介孔分子筛MCM-41进行纳米TiO2的组装。运用XRD、FT-IR、N2吸附-脱附等表征手段对其结构特征和氧化钛分散状态进行了研究,结果表明：TiO2与MCM-41端基硅氧键反应形成Ti-O-Si键;纳米TiO2不仅进入孔道,较均匀地修饰了介孔分子筛MCM-41的孔壁,而且使介孔分子筛MCM-41仍保持有序的孔道结构。     

激光和等离子体混合法氮化钛表面

采用激光和氮等离子体混合方法在大气气氛下对钛样品表面进行处理,获得了钛氮化合物表层.利用X射线衍射仪(XRD)对氮化处理后的样品测试,得到了样品的相结构.分别使用该方法与普通激光氮化方法,在相同条件下对样品表面进行氮化处理,结果表明通过混合方法提高了氮化物含量,并有效地抑制了氧化发生.讨论了氮等离子体流量对混合法氮化效果的影响.随着氮等离子体流量的增加,氮化物含量增加;但是当氮等离子体流量＞0.8m3/h后,氮化所需活化氮达到饱和,氮化物含量不再增加.     

纳米SiO2表面改性及其应用在复合材料中的研究进展

简单介绍了纳米SiO2改性目的及改性机理,对近年来国内外纳米SiO2表面改性方法及聚合物/纳米SiO2复合材料（PSN）的应用进行了阐述,并对未来的研究内容和方向提出了展望。     

Influence of Surface Modification on Tribo-Performance of Hybrid Glass/PTFE Fabric Composite with Phenolic Resin Binder

The fabric/phenolic composites with the pure and silanized hybrid glass/PTFE fabric were prepared by dip-coating of the hybrid glass/PTFE fabrics in a phenolic resin. The friction and wear performances of the resulting fabric composites were evaluated using pin-on-disc wear tester. The composition change of the glass fabric in hybrid glass/PTFE fabric after silanization was analyzed by FTIR spectroscopy. The morphologies of the composite structures and the worn surfaces of the composites were analyzed by means of scanning electron microscopy (SEM). The results show that the fabric/phenolic composite with the β-aminoethyltrimethoxylsilane silanized hybrid glass/PTFE fabric can obtain the highest load-carrying capacity and the best wear-resistance, followed by the composite with γ-glycidoxypropyltrimethoxysilane silanized hybrid glass/PTFE fabric. Chemical reactions have achieved as the hybrid glass/PTFE fabric was silanized with β-aminoethyltrimethoxyl silane or γ-glycidoxypropyltrimethoxy silane, which contribute to strengthen the bonding strength between the fabric and the adhesive and hence to improve the tribological properties of the hybrid glass/PTFE fabric composites.     

包装废聚丙烯复合改性沥青防水材料研究

利用回收的包装废弃聚丙烯、废胶粉代替普通聚合物改性剂，采用复合改性的技术方法，对普通沥青进行改性，提高基质沥青的防水性能。结果表明，改性后沥青的软化点、5℃延度提高，针入度降低，不透水性得到明显提高；不同混合比改性效果显示复合改性沥青综合性能优于单一改性剂直接改性。通过FT-IRF、微观结构分析，对复合改性沥青的高、低温性能，抗变形能力进行了研究，表明改性剂的溶胀及其与沥青形成的空间网络结构、银纹支化、应力剪切作用是产生改性效果的重要原因。