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51.
Through the addition of N‐hydroxymethyl acrylamide as a potential crosslinker, water‐absorptive blend fibers of copoly(acrylic acid–acrylamide) and poly(vinyl alcohol) with three‐dimensional network structures were prepared with heat‐crosslinking technology after fiber formation. Fourier transform infrared, scanning electron microscopy, dynamic mechanical analysis, and thermogravimetry were used to analyze the structures and properties of the fibers. The tensile behavior and absorbent capacities of the fibers were also studied. The results showed that there were lots of chemical crosslinking points in the fibers, the compatibility of copoly(acrylic acid–acrylamide) and poly(vinyl alcohol) was perfect, and the tensile properties of the fibers could be improved effectively through stretching in a vapor bath. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3353–3357, 2006 相似文献
52.
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
53.
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
54.
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
55.
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
56.
An Yong Lee Jongguk Yim Youngjin Choi 《International Journal of Control, Automation and Systems》2014,12(5):1102-1109
This paper presents a scaled Jacobian transpose based control method for robotic manipulators as a modification of a conventional Jacobian transpose based method. The proposed method has several advantages such as it shows faster convergence and better tracking performance than the conventional method, furthermore, it does not have any singularity problem similar to the conventional method. The scaled Jacobian transpose is obtained by collecting each pseudoinverse of the column vector of the Jacobian matrix. The proposed method performs a given task well under singular configurations while minimizing the task error. Finally, a few comparative studies with the conventional method are provided to show the effectiveness of the proposed method through simulations. 相似文献
57.
Hai Huang Haichao An Wenrui Wu Lingyan Zhang Beibei Wu Weipeng Li 《Structural and Multidisciplinary Optimization》2014,50(5):883-898
According to the mission of a satellite with maneuver capability, the collaborative optimization (CO) method was introduced for the satellite system design, and the related multidisciplinary design optimization (MDO) model was established. The possessing and needed velocity increments Δv and Δv n e e d were taken as the measurement of maneuvering capability of the studied satellite, which were then combined with total mass of the satellite to form the optimization objective in the systematic level of the MDO problem. The design variables and constraints of the MDO problem dealt with disciplines or subsystems as guidance, navigation and control (GNC), power, and structure, and corresponding engineering analysis models were also built. A program system to solve the MDO problem wasdeveloped by integrating a non-nested CO method, the commercial and user-supplied codes on framework software iSIGHT. The result showed that the satellite performance could be obviously improved, which also indicates MDO technique is feasible and effective for the spacecraft design problem. The modeling and optimization procedure of the work can be referred for further research and engineering design. 相似文献
58.
为了解决多属性数据分类问题,提出了一种基于模糊优选模型与聚类分析的分类方法(FO-CA)。首先由模糊优选模型得到有序综合指标数据集,其中在权重阶段提出了距离差异度并以此为依据构建了一种组合主客观权重的赋权方法;然后采用聚类分析将有序综合指标数据集聚类为几个簇进而分类;最后选取UCI中的Iris、Wine和Ruspini 3个数据集进行仿真实验。实验结果表明,该分类方法相比模糊优选方法及K-Means算法能获得更好的分类结果,对决策者有一定的参考价值。 相似文献
59.
The thermal properties of amorphous gelatin films and gelatin films with renatured structural order were measured by using conventional and temperature modulated differential scanning calorimetry (DSC). Different amounts of gelatin structural order associated with a melting enthalpic change in the DSC measurement were prepared based on different gelatin drying conditions. Two consecutive heating and cooling DSC measurements on the gelatin films showed that there was no change in the glass‐transition temperature (Tg) for the amorphous gelatin but there was a decrease in the Tg for the structural gelatin on the second DSC scan. This decrease was attributed to the plasticizing effect from the release of originally hydrogen‐bonded water associated with the structural gelatin. In addition, a reversing endotherm observed upon melting of the structural gelatin during a temperature modulated DSC measurement indicated that the transition of bound water to free water occurred as the partial triple‐helix gelatin melted. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1795–1801, 2006 相似文献
60.
本文介绍了预加氢反应器的典型结构,分析了制造上的难点,有针对性地提出了解决难点的特殊工艺方案,记录了实际制造经验数据,对类似设备的制造有着重要的参考价值。 相似文献