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121.
122.
Ji‐Sun Im Ju‐Hyung Lee Seung‐Kook An Ki‐Won Song Nam‐Ju Jo Jang‐Oo Lee Kohji Yoshinaga 《应用聚合物科学杂志》2006,100(3):2053-2061
A new type of polyimide/silica (PI/SiO2) hybrid composite films was prepared by blending polymer‐modified colloidal silica with the semiflexible polyimide. Polyimide was solution‐imidized at higher temperature than the glass transition temperature (Tg) using 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 4,4′‐diaminodiphenyl ether (ODA). The morphological observation on the prepared hybrid films by scanning electron microscopy (SEM) pointed to the existence of miscible organic–inorganic phase, which resulted in improved mechanical properties compared with pure PI. The incorporation of the silica structures in the PI matrix also increased both Tg and thermal stability of the resulting films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2053–2061, 2006 相似文献
123.
Sang-Gon Kim Jong-Sung Park Jae-Sul An Kug Sun Hong Hyunho Shin Hyungsun Kim 《Journal of the American Ceramic Society》2006,89(3):902-907
Various types of crystalline ceramic fillers (TiO2 , ZrO2 , Al2 O3 , MgO, and cordierite) were added to BaO–ZnO–B2 O3 –SiO2 (BZBS) glass (5–20 wt%), and the resultant dielectric constant, coefficient of thermal expansion (CTE), and optical reflectance were investigated for the application of the composites to the barrier ribs in plasma display panels. All the investigated fillers were partially dissolved into the glass at the fabrication temperature (575°C), and the residual fillers were aligned along the boundaries of sintered glass frits. By considering all aspects of the properties, the addition of TiO2 fillers of about 10 wt% to BZBS glass was the most desirable of the types of fillers investigated. The addition of TiO2 filler (10 wt%) yielded 61% in optical reflectance, 8.3 × 10−6 K–1 in coefficient of thermal expansion, and 15.5 in dielectric constant, which were properties comparable with the currently used Pb-based barrier ribs. 相似文献
124.
Yong?An?Jung Du?Young?Choi Seung?Bum?Hong Kyung?Ho?RowEmail author 《Korean Journal of Chemical Engineering》2003,20(4):705-708
Reversed-phase high-performance liquid chromatography was successfully developed for the simultaneous and rapid separation for the main whey proteins, α-Lactalbumin and β-Lactoglobulin. This method consisted of a linear gradient of the two mobile phases of 0.1% trifluoroacetic acid in water and 0.1% trifluoroacetic acid in acetonitrile. The total run time for this separation was approximately 30 min, and α-Lactalbumin was eluted followed byβ- Lactoglobulin. The injection volume was fixed at 20 μl and the flow rate was 1 ml 1/min. The optimum mobile phase composition and gradient conditions to separate α-Lactalbumin and β-Lactoglobulin (A+B) were experimentally obtained at the 15 μm particle with a pore size of 300 Å on the linear-gradient mode. 相似文献
125.
The influence of ultrafine coal filler (UFC) content on tensile properties, water absorption, and biodegradability of soy protein plastics were investigated. The addition of UFC in the soy protein plastics, with different content of glycerol as a plasticizer, was at different ratio varying from 10:0 to 6:4. Blend sheets of the soy protein composites were prepared by the compression molding processing. The results show that, with 23.08 wt % glycerol, the tensile strength and elongation at break for the soy protein sheet with coal filler (range from 5 to 30 parts) can be enhanced as compared with nonfilled soy protein plastics. Water resistance of the soy protein plastics improves with the increase in UFC content. The derivative thermogravimetry (DTG) curves indicate a double‐stage degradation process for defatted soy flour (SPF), while three‐stage degradation process for soy plastics and the soy protein composites. FT‐IR, XPS, and SEM were applied to study the interfacial interaction between coal macromolecules and soy protein molecules in UFC filled soy protein plastics. The results demonstrated that there is strong interfacial interaction in the soy protein plastics caused by the compression molding processing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3134–3143, 2006 相似文献
126.
Water‐insoluble polyaspartyl polymers were synthesized by using water as medium instead of organic medium. Taking Ca2+ as a reference, the binding of several heavy‐metal ions, including Pb2+, Cd2+, Hg2+, Cr3+, Cu2+, and Mn2+, by polyaspartyl polymers was studied. The experimental results revealed that polyaspartate is an excellent binding agent for the investigated heavy‐metal ions. These cation ions were bound to polyaspartate polymer by the same mechanism as Pb2+, which can be explained by ion exchange model. Since polyaspartate has a protein‐resembling structure that is sensitive to trace heavy metal, it was used to remove some trace heavy‐metal elements in Chinese herbal medicines. It was found that polyaspartate material was an effective agent for the removal of Pb2+, Cd2+, and Hg2+ ions from glycyrrhizin, angelica, and gynostemma pentaphyllum. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
127.
在全球变化等多种因素的影响下,许多流域的泥沙问题严重,泥沙管理的重要性日益突出。通过对联合国教科文组织国际泥沙计划所开展的案例研究进行综述,认识到自然地理特征、社会经济条件、水利工程建设对流域产沙、输沙和水资源利用有重要影响。土壤侵蚀加速、水库淤积、下游输沙量减少和生态平衡破坏是目前全球各大流域面临的主要问题。综合各项案例,研究泥沙管理技术,提出流域综合泥沙管理的策略,包括水库淤积管理、推移质泥沙管理、土地管理和水土保持等技术手段,以及法律、行政和组织措施。 相似文献
128.
129.
对反应过程所需催化剂种类及其各影响因素进行了考察。研究表明,大孔强酸性离子交换树脂可替代无机酸作为催化剂用于该反应,其中以未经硫基化处理者为佳;原料中水分的存在不利于产物收率和质量,应控制水的质量分数在1%以下。本研究确定的较佳工艺条件为反应温度65℃,停留时间15min、苯酚/对-异丙烯基苯酚摩尔比20,对应的反应收率为98.5%。对双酚A副产物的处理提供了有效方法。 相似文献
130.
以苯乙烯/丙烯酸丁酯(St/BA)为共聚单体,进行了微乳液聚合反应,测定了共聚物组成和共聚单体的竞聚率。由竞聚率计算了共聚物分子的链段分布,分析了共聚物分子的微观结构。 相似文献