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《Composite Interfaces》2013,20(7-9):829-839
Composites were fabricated with alkali (10%, 15% and 20%) treated bamboo fibers incorporated to the extent of 50% (by volume) and polyester resin. Impact test was made on bamboo strips and composites samples. It was observed that the fracture energy undergoes an increase from untreated to alkali treated bamboo strips. Alkali treated bamboo fiber composites show higher fracture energy value than the untreated bamboo fiber composites. The phenomenal change was quite evident from scanning electron micrographs of the fractured surface. Considering the effects of all factors, the work of fracture shows maximum value in the case of 20% alkali treated bamboo strip composites. It was also observed that the rate of increase of work of fracture value is much higher in the case of composite samples than the bamboo sample. It was explained on the basis of synergism obtained by improved interfacial adhesion between fiber and matrix, and removal of hemicellulose from the bamboo itself, which was evident from the intermolecular H-bonding formation studied by FT-IR. 相似文献
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Improvement of resin impregnation into glass cloth by silane treatment in resin transfer molding 总被引:1,自引:0,他引:1
《Composite Interfaces》2013,20(7):683-689
An evaluation method was proposed for resin impregnation using resin transfer molding of unsaturated polyester matrix composites with silane-treated glass cloth. The determination of whitening of the composite was carried out as a parameter of incompleteness of resin impregnation. The change of whitening with silane concentration was compared with the bending modulus as a parameter of chemical reinforcement. The materials used were unsaturated polyester resin as a matrix and methacryloxypropyltrimethoxysilane as a silane coupling agent for glass cloth. Resin transfer molding was used to produce four plies of glass cloth laminates by impregnating the resin. The silane-treated glass cloth repressed whitening above 0.026 w/w% of silane in aqueous solution, while the chemical reinforcement due to silane gave no appearance below 0.2 w/w% based on the bending test of the laminates. The large difference between the concentrations suggested that silane has a couple of functions, that is, chemical reinforcement and physico-chemical resin wettability. 相似文献
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本文报道了由七种长链季铵盐制得的高氯酸根离子选择电极,测定了这些电极的Nernst响应范围和检测下限,并研究了各种阴离子的干扰。通过大量实验测得,随着季铵盐分子中取代烷基碳链的增长,电极电势响应范围增宽、检测下限降低、抗外部阴离子干扰能力增强。若取代烷基碳链过长,则季铵盐纯化困难,在膜相中溶解度降低,不适于电极的研制。根据用上述七种选择电极在相同水相条件下测得的数据表明,阴离子的干扰次序为:PA~->ClO_4~->BF_4~->SCN~->I~->ClO_3~->N_3~->N_3~->CN~-~Br~->H_2PO_4~->F~->Cl~-。这些数据对阴离子选择电极研制与相转移催化反应研究均有现实意义。 相似文献
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ShengBaohuai ZhouSongping 《分析论及其应用》2005,21(1):27-37
In the present paper,we prove that the Bernstein-Kantorovic operators have the ability of preserving translation property in both C and L^p norms. 相似文献
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稠杂环化合物研究 i: 3-(4'-吡啶基)-6-芳基-均-三唑并[3,4-b]-1,3,4-噻二唑的合成及其抗菌性能 总被引:6,自引:0,他引:6
本文研究3-(4'-吡啶基)-4-氨基-5-巯基-1,2,4-三唑(1)与取代苯甲酸(2s-s)在氯化氧磷催化下的反应, 制得19种新的3-(4'-吡啶基)-6-芳基-均-三唑并[3,4-b]-1,3,4-噻二唑(3a-s), 确证了结构。初步观察了它们在约0.01%的浓度时, 对枯草杆菌, 大肠杆菌, 变形杆菌和金黄色葡萄球菌繁殖的抑制作用。 相似文献
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用固相法合成了促δ-波睡眠肽Trp-Ala-Gly-Gly-Asp-Ala-Ser-Glu(DSIP)及其十四种类似物和三个短肽,研究了结构与功能的关系,类似物的设计,主要考虑在分子中引入D-氨基酸以抑制酶的作用和增强稳定性,以及引入疏水侧链氨基酸如Phe和Trp等。位置的修饰主要在1,3,4,5,8和9位,即:D-Trp[1],Tyr[1],Tyr[1]Phe[5],D-Trp[1]Phe[8],Trp[3,4],D-Trp[3,4],D-Trp[1,3,4]Phe[8],D-Glu[9],D-pF-Phe[3,4]Phe[8]D-Glu[9],Phe[5],Glu[5]Asp[9],Tyr[5]Asp[9],Ala[7]和Asp[9]-DSIP以及Trp-Ala-Gly-Gly-Asp,Trp-Ala-Gly-Gly-Glu和Trp-Gly-Glu.合成肽的纯度经氨基酸组成分析、元素分析、薄层层析以及纸电泳鉴定。生物试验表明D-Trp[1],Tyr[1],Tyr[1]Phe[5],Ala[7]-DSIP无促眠活性;而Phe[5]-DSIP的促眠活性与DSIP相接近,其他类似物的生物试验结果将另文发表。 相似文献
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酯化硅胶的物理结构和表面性质的研究 总被引:3,自引:0,他引:3
本文利用正庚醇或正辛醇与硅胶表面羟基反应制备了酯化硅胶。测定了酯化硅胶的物理结构、水蒸气吸附等温线、润湿热、差热分析和红外光谱。结果表明: (1)所有酯化硅胶的真密度(dT)、比表面(S)和比孔体积(V)均减少, 而有观密度(dA)增加, 但平均孔半径(r)变化不大; (2)酯化硅胶是憎水的, 其对水蒸气吸附, 以及对水和环己烷的润湿热均显著减少; (3)酯化硅胶的表面酯基在空气中于235-350℃破坏; (4)酯化反应是可逆的, 硅胶表面酯基在水中大约可水解41-47%。 相似文献
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