Ways of strengthening biodegradable soy‐dreg plastics

Biodegradable plastics (GSD) based on soy dreg (SD) were prepared by compression‐molding, with glycerol as the plasticizer and glutaraldehyde (GA) as the cross‐linker. The structure and properties of the GSD sheets were investigated by Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), scanning electron microscope (SEM), and tensile test methods. The results indicate that when GA content was 6.8%, the tensile strength (σ_b) of the sheet reached the maximum value of 14.5 MPa. Moreover, the strength and water resistance of the sheets coated with castor‐oil‐based polyurethane/nitrochitosan interpenetrating network (IPN) coating were significantly enhanced to 24.6 MPa in the dry state and 9.8 MPa in the wet state. Simultaneously, the test of biodegradability of the GSD sheet in a mineral salts medium containing microorganisms and agar proved that GSD could be fully biodegradable. This work has provided a novel way to utilize low‐cost SD to prepare biodegradable plastics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 422–427, 2003     

The Moisture Distribution of High Moisture Content Rough Rice During Harvesting, Storage, and Drying

The kernel moisture content (MC) distribution of five varieties of double season rice was tested during the process of harvesting, drying, and tempering. Significant kernel MC variance was found to exist within the panicle. Binodal kernel MC distribution frequency was found at harvest. The MC distribution of five varieties during harvesting and drying showed similar trend of uniformity. To investigate the mechanism of moisture transport among rice kernels under low temperature, the kernel MC distribution of rice planted in Northeastern China was also investigated after stacked for over one month under the temperature of -20°C. The moisture exchange among rice kernels was found greatly influenced by environmental factors.     

聚合物纳米复合材料的研究进展

介绍了聚合物基纳米复合材料的种类及制备方法，详细介绍了聚合物／层状硅酸盐纳米复合材料的研究，包括聚合物／层状硅酸盐纳米复合材料的种类、性能及研究的新进展。     

Effects of reaction and cure temperatures on morphology and properties of poly(ester‐urethane)

Poly(ester‐urethane) was synthesized from poly(ethylene glycol adipate) (PEG) and 2,4‐toluene diisocyanate (TDI) to study the effects of reaction temperature and cure temperature on the crystallization behavior, morphology, and mechanical properties of the semicrystalline polyurethane (PU). PEG as soft segment was first reacted with TDI as hard segment at 90, 100, and 110°C, respectively, to obtain three kinds of PU prepolymers, coded as PEPU‐90, PEPU‐100, and PEPU‐110. Then the PU prepolymers were crosslinked by 1,1,1‐tris (hydroxylmethyl) propane (TMP) and were cured at 18, 25, 40, 60, and 80°C. Their structure and properties were characterized by attenuated total reflection Fourier transform infrared, wide‐angle X‐ray diffraction, scanning electron microscopy, dynamic mechanical analysis, and tensile testing. With an increase of the reaction temperature from 90 to 100°C, the crystallinity degree of soft segment decreased, but interaction between soft and hard segments enhanced, leading to the increase of the glass transition temperature (T_g) of soft domain and tensile strength. When the cure temperature was above 60°C, miscibility between soft and hard segments of the PEPU films was improved, resulting in relatively low crystallinity and elongation at break, but high soft segment T_g and tensile strength. On the whole, all of the PEPU‐90, PEPU‐100, and PEPU‐110 films cured above 60°C possessed higher tensile strength and elongation at break than that of the films cured at other temperatures. The results revealed that the reaction temperature and cure temperature play an important role in the improvement of the crosslinking structure and mechanical properties of the semicrystalline PU. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 708–714, 2006     

解析“自然叠加法”在建筑环境设计中的应用——以新镇区建筑环境设计为例

人与自然的关系不能仅停留在相互依赖的层面上,人类应借助自己的思想与智慧。主动的与自然和谐共处。并处理好为促进人类发展而进行的。对于自然环境局部必要的改造与利用。譬如在改造自然环境时,应尊重自然发展规律;在利用自然资源时。应考虑可持续发展等问题;在对建筑与环境的设计实践中,应找寻出可依据的自然规律,保护、尊重环境及科学、合理的利用自然。并以恰当的方式应用手设计实践,这就是文章的研究主旨。     

LLC谐振变换器的扩展描述函数法建模

给出了LLC谐振变换器的等效电路,基于扩展描述函数法建立了该等效电路的小信号模型、得到了LLC变换器的稳态解及其直流电压增益特性。借助PSpice仿真软件得到了该变换器在不同开关频率和不同电路参数下输出变量对控制变量的频率特性曲线。分析了开关频率、输入电压、占空比、品质因数和负载等主要参数对频率特性的影响。所作的工作对变换器参数的优化设计、闭环控制及动态性能设计具有指导意义。     

多媒体教学服务系统的设计

本文从实际使用出发,提出了多媒体教学系统的设计思路,主要介绍了多媒体教学系统的系统结构、主要系统功能等。     

谈谈C5的综合利用

本文简单地介绍了C5的产量和现状。主要讨论了C5综合利用，其中包括C5生产TAME、石油树脂、叔戊醇、加氢制戊烷、在超强酸条件合成金刚烷和某厂利用C5流程图。C5资源的合理利用不仅是有效利用石油资源的组成部分，也是改善产品结构，提高产品质量、增加企业效益的重要途径之一。     

荔浦县旅游形象定位研究

根据荔浦县的自然地理、文化传统和社会心理方面的特点,认为荔浦旅游形象的核心要素是以溶洞为代表的旅游资源和以荔浦芋为代表的民俗文化,因此荔浦县的旅游形象可提炼为"洞绝天下,‘芋'(誉)满神州".     

构建中国海外投资促进体系研究综述

基于经典海外投资理论、发达国家促进海外投资的经验,分析了海外投资的宏观环境,包括海外投资发展阶段分析、环境分析和影响因素分析,并从政府和企业的角度阐述了两者在促进海外投资中的作用,最后结合目前实际,分析了金融危机背景下我国企业的应对策略。