熔模铸造型壳性能的改进及分析

高强度水玻璃型壳工艺与填砂式普通型壳工艺相比有许多优点。少层薄壁高强度水玻璃型壳中加入铝矾土、采用高粉液比涂料和面层型壳硬化前的干燥等工艺措施可有效提高型壳的高温强度和热稳定性，改善铸件表面质量，提高铸件表面精度。     

Analytical Algorithms for the Blend Ratios by Fibre-bundle Tensile Curves Part Ⅱ:Calculations of the Modulus Method and the Percentage Method

The principles for the modulus method and the percentage method are established and discussed in the part following Part Ⅰ of the series papers, in which we proposed the various algorithms of the strength method and the work method. The samples of Wool/PET blended fibre bundles,the method of fibre-bundle tensile tests and the typical specific stress-extension curves from the fibre bundles with different blend ratios are the same as in Part Ⅰ. Itcan be found that the theoretical results estimated by the modulus and percentage methods accord with the experimental values highly though the calculations of the two methods are slightly more complex than those of the strength and work methods. Especially, using the modulus method can not only avoid the influence of the error caused by the determination of the tensile curve of no fibre breaking in stretching, Y (e), but also need not to know the tensile curves of mono-component fibre bundles in certaincalculation. The latter advantage of the modulus method exists in the percentage method too, but it should adopt the improved calculation of ones.     

FIBRE REINFORCED COMPOSITES BASED ON NOVEL BLEND MATRICES

A series of glass fibre reinforced composites based on novel blend matrices were fabricated us-ing reaction injection moulding (RIM) processing.The blends were made of sub-sequentialinterpenetrating polymer networks of acrylic-polyurea or acrylic-copoly(urea-isocyanurate).Themechanical and thermal properties were characterized by tensile test and dynamic mechanical ana-lysis.The fracture data from single edge notch bend tests were analysed using fracture mechanicsfor the composites to give K_(IC) and G_(IC).The correlation between reaction kinetics and morphologyof the blend and the composite properties were discussed.The investigations showed that the novelblends have good bonding property on glass fibre,thus good processability in RIM,and the re-suited composites have good mechanical and thermal properties.     

PBT/PET共混体系熔融过程的DSC研究

用共溶解-沉淀法制得的共混物PBT/PET各组分分别结晶,PET的存在对PBT的结晶有抑制作用;熔融共混PBT/PET的DSC图谱与共混时间有关;超过一定时间后只呈现单一的熔融峰,其本质是由于酯交换使共混物变为共聚酯,而非互溶共晶.     

甲壳素/纤维素共混粘胶长丝的研制

为了探讨不同共混比的纤维素黄原酸酯、甲壳素黄原酸酯共混溶液所制得长丝的形态结构和物理性能，选择了甲壳素质量分数分别为0％、2.89％、6．46％的长丝进行研究。普通粘胶长丝、共混长丝的表面均有沟槽，随着甲壳素质量分数的增加，沟槽量变少，且纤维表面变得粗糙、不光滑。在试验范围内，与纯粘胶纤维相比，共混长丝的湿干强度降低，但降低的幅度不大。随着共混长丝中甲壳素质量分数的增加，长丝的结晶度、取向度、模量、密度随之减小；纤维回潮率、可及度呈现下降趋势，但降低的幅度都不大。共混纤维对大肠杆菌、葡萄球菌等菌类的抑菌率均在26％以上，为合格的抑菌产品。     

聚乙烯醇/超细羊毛粉体共混膜的制备及其染色性能

为了改善以及较好地研究聚乙烯醇纤维的染色性能,制备了不同粉体含量的PVA/超细羊毛粉体共混膜,同时探讨了PVA/超细羊毛粉体共混溶液的可纺性能.超细羊毛粉体的平均粒径为2.01μm.SEM扫描电镜显示,超细羊毛粉体与PVA之间有较好的相容性.随着共混膜中超细羊毛粉体含量的增加,共混膜的上染率,红度(a*)值以及K/S值都逐渐的增加.当超细羊毛粉体含量为33.3%时,PVA/超细羊毛粉体共混膜的染色性能几乎同超细羊毛粉体的染色性能一样;当超细羊毛粉体的含量超过33.3%时,PVA/超细羊毛粉体共混膜的染色性能会大幅度增加,甚至这些共混膜的K/S值会超过超细羊毛粉体的K/S值.     

高吸水涤纶纤维的结构和染色性研究

将PET与共聚酯共混纺制中空共混纤维,经碱处理后形成多孔的高吸水涤纶。本文通过X—射线衍射仪,分光光度计,扫描电镜和热收缩仪等测试对高吸水涤纶纤维和共混纤维的结构和染色性进行了研究,目的在于探索高吸水涤纶染色机理。研究结果发现高吸水涤纶纤维与共混纤维相比较,不仅具有许多微孔,而且结晶度高,晶粒尺寸大,单位非晶体积大,非晶区结构紧密;高吸水涤纶的上染量与保水率呈指数关系。由此推论高吸水涤纶上染量高主要是由于纤维中微孔的吸附染料作用。     

体育教育专业技能训练实践教学的改革与探索——以陇南师专体育教育专业为例

基于对陇南师专体育教育专业教学法实践教学环节现状的分析结果,对实践教学技能训练的内容、方法、组织形式等进行了改革与探索,设计的实践教学环节对学生综合教学能力的提高效果显著,并为体育教育专业学生教学技能的提高及后续发展奠定了良好的基础．     

聚碳酸酯多孔增透膜的制备及性能研究

将聚碳酸酯(PC)与聚苯乙烯(PS)进行溶液共混后旋涂成膜(spin-coating),然后利用共混薄膜在成膜后期及热处理过程中会产生相分离的特点,采用溶剂抽提技术,将薄膜中的PS组分去掉来制备聚碳酸酯基多孔增透膜,并通过改变两高分子组分间的质量比及溶液浓度来调节薄膜的增透效果.由紫外-可见分光光度计的测试结果可知:在二氯甲烷溶剂(3 wt%)中,PC/PS=70/30(w/w)条件下形成的PC多孔膜,其最大透过率可达到96%以上,此外该薄膜还具有聚碳酸酯材料的优良力学性能及热稳定性等优点,是一种很有应用前景的薄膜材料.     

人性的呓语与节制的抒情——试论早期自叙传小说的两种倾向

中国现代自叙传小说是融入了作者情感倾向和人生经历的虚构艺术。郁达夫等情绪派和郑振铎等写实派的创作代表了20世纪20年代自叙传小说的两种倾向。这两种不同的自叙传小说风格的形成与作家自身的文学观念及所处的文学环境密切相关。