填料对反-1,4-聚异戊二烯性能的影响

研究了填料对反－1，4－聚异戊二烯（TPI）硫化胶和混炼胶的物理机械性能和结晶性能的影响。结果表明，在TPI中加入填料后，其硫化胶的300％定伸应力随填料用量的增加而增加，拉伸强度则在填料用量为20份时达到最大值；加入填料同时能降低TPI混炼胶的结晶度，填料用量增加，TPI混炼胶的结晶下降；且填料增强效果越好，结晶度下降越大。     

溶胶-凝胶法制备多孔陶瓷的研究进展

本文综合论述了溶胶-凝胶法制备多孔陶瓷的工艺研究进展以及影响溶胶-凝胶法制备多孔陶瓷的主要因素，并讨论了今后溶胶-凝胶法制备多孔陶瓷的主要研究问题及其发展前景。     

Relative image similarity learning with contextual information for Internet cross-media retrieval

With the fast explosive rate of the amount of image data on the Internet, how to efficiently utilize them in the cross-media scenario becomes an urgent problem. Images are usually accompanied with contextual textual information. These two heterogeneous modalities are mutually reinforcing to make the Internet content more informative. In most cases, visual information can be regarded as an enhanced content of the textual document. To make image-to-image similarity being more consistent with document-to-document similarity, this paper proposes a method to learn image similarities according to the relations of the accompanied textual documents. More specifically, instead of using the static quantitative relations, rank-based learning procedure by employing structural SVM is adopted in this paper, and the ranking structure is established by comparing the relative relations of textual information. The learning results are in more accordance with the human’s recognition. The proposed method in this paper can be used not only for the image-to-image retrieval, but also for cross-modality multimedia, where a query expansion framework is proposed to get more satisfactory results. Extensive experimental evaluations on large scale Internet dataset validate the performance of the proposed methods.     

Memristor crossbar-based unsupervised image learning

This letter presents a new memristor crossbar array system and demonstrates its applications in image learning. The controlled pulse and image overlay technique are introduced for the programming of memristor crossbars and promising a better performance for noise reduction. The time-slot technique is helpful for improving the processing speed of image. Simulink and numerical simulations have been employed to demonstrate the useful applications of the proposed circuit structure in image learning.     

改性低毒脲醛树脂的合成及性能研究

采用六亚甲基四胺做催化剂，加入聚乙烯醇（PVA）、三聚氰胺和硫脲作为改性剂，通过降低甲醛与尿素物质的量比、采用尿素分批加入的合成方法，制备出改性低毒的脲醛树脂（UF），使游离甲醛质量分数低于0．30％；采用捏合和模压成型方法，将改性和普通UF树脂分别与剑麻纤维（SF）制备UF／SF共混复合材料，研究了复合材料的力学性能和吸水性能。结果表明，甲醛和尿素物质的量比为1．1时，游离甲醛质量分数降低到0．16％；甲醛和尿素物质的量比为1．2时，三聚氰胺、PVA及硫脲加入量分别为尿素总量的2．0％，1．5％，1．0％（质量分数）时，游离甲醛质量分数降低到了0．10％，粘度达到0．41Pa·S，贮存期大于80d；改性UF／SF复合材料的性能比普通UF／SF复合材料的冲击性能和耐磨性能分别提高了114％和261％。     

Mechanical properties and thermal stability of double‐shell thermal‐energy‐storage microcapsules

Double‐shell‐structured microcapsules encapsulating phase‐change materials (micro‐PCMs) with an average diameter of 5–10 μm were successfully fabricated with a melamine–formaldehyde resin as the coating material. The mechanical properties of the obtained piled micro‐PCMs, tested under compression, were evaluated with a pressure sensor. Typical stress–strain curves showed that both the single‐shell‐ and double‐shell‐structured microcapsules had yield points and maximum point pressures. The morphological changes in the shell surface confirmed the existence of yield points by scanning electron microscopy. When the pressure was beyond the yield point, the microcapsules showed conventional plastic behavior, and the double‐shell structure was more mechanically stable than the single‐shell one. Differential scanning calorimetry analysis results revealed that the properties of the phase‐change materials experienced no variation after coating with a single‐shell‐ or double‐shell‐structured polymer. Thermogravimetric analysis showed that the double‐shell‐structured micro‐PCMs experienced a weight loss of only about 5% from 86.3 to 232°C but did so more rapidly from 232 to 416°C. Thermoregulation was determined with periodical heating and cooling tests. The data showed that the micro‐PCMs changed temperature in a narrow range of 20–25°C with a time lag of 20 min to reach the maximum or minimum temperature in comparison with a reference temperature of 18–28°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1295–1302, 2007     

复杂制品注塑成型模拟分析

应用CAE软件MoldflowPlasticsInsight4.1的充模、保压、冷却、翘曲等分析模块,对汽车尾门饰件注塑成型过程进行CAE分析,研究了浇口位置、工艺参数等对制品性能的影响。最后,基于模拟结果分析了制品翘曲的主要原因,为模具设计及注塑工艺的确定提供参考。     

高固体分丙烯酸树脂相对分子质量的研究

采用溶液聚合法合成高固体分丙烯酸树脂,用凝胶渗透色谱(GPC)法分析引发剂的种类和用量、反应温度及聚合工艺对丙烯酸树脂的相对分子质量及其分布的影响。结果表明,选用偶氮二异丁腈和过氧化苯甲酰两种引发剂进行复配可提高聚合物的相对分子质量;采用“饥饿态”聚合工艺进行聚合反应可有效控制聚合物的相对分子质量,且相对分子质量分布均匀,分散度小于2;当引发剂用量为2%,在110℃的反应条件下制得的丙烯酸树脂的综合性能优异,固含量超过70%,相对分子质量可达4万。     

Structure and properties of regenerated cellulose films coated with polyurethane–nitrolignin graft‐IPNs coating

A regenerated cellulose film (RC) was coated with a graft‐IPNs coating, which was composed of castor oil‐based polyurethane and 2.8 wt % nitrolignin (NL), to obtain water‐resistant films. The effects of NCO/OH molar ratio and different polyols, such as 1,4‐butanediol (BDO) and trimethanol propane (TMP), on the structure and properties of the coated RC films were investigated. With an increase of the NCO/OH molar ratio, the tensile strength of the coated films increased, but the water resistivity and size contraction hardly changed. The coated films with TMP exhibited the higher breaking elongation at 1.5 of the NCO/OH molar ratio, while those with BDO have more excellent tensile strength, water resistivity, and dimensional stability. The coated films with the graft‐IPNs coating exhibited superior water resistivity and dimensional stability. The light transmittance of the coated films was more excellent than that of the RC film. Moreover, the results from the IR and electron probe microanalysis (EPMA) showed that the chemical bonding occurred between cellulose and coating, and the introduction of NL plays an important role in the enhancement of the interface adhesion of the coated films. Atomic force microscopy (AFM) depicted the flat and dense surface of the coated films, which restricted the water vapor penetration and the size contraction, resulting in the enhancement of water resistivity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1799–1806, 2002