超高分子量聚乙烯纤维制备技术进展

介绍了超高分子量聚乙烯(UHMWPE)纤维的物理、化学等性质,列举了国内外生产UHMWPE纤维的主要厂家,重点介绍了目前UHMWPE纤维的制备技术现状,包括干法凝胶纺丝、湿法凝胶纺丝以及其他纺丝方法等,分析了UHMWPE纤维现有制备过程中所面临的问题,并提出进一步发展方向。     

循环应用低剂量环磷酰胺对黑色素瘤荷瘤小鼠调节性T细胞的影响及抗瘤作用

目的观察循环应用低剂量环磷酰胺(CTX)对黑色素瘤荷瘤小鼠调节性T细胞(Treg)的影响及抗瘤作用。方法通过皮下接种黑色素瘤细胞B16制备黑色素瘤荷瘤小鼠模型;对荷瘤小鼠分别经腹腔单次或循环注射CTX,每隔7d给药1次,共3次,应用流式细胞术检测小鼠脾脏中CD4+CD25+Foxp3+Treg的含量;培养小鼠骨髓来源的树突状细胞(DC),将DC与脾T淋巴细胞混合培养,应用ELISA法检测脾T淋巴细胞干扰素γ(IFNγ)的分泌量;同时测量肿瘤的大小,绘制肿瘤生长曲线,并观察各组荷瘤小鼠自身免疫病的发生情况。结果CTX的最佳应用剂量为100mg/kg。随着荷瘤时间的延长,荷瘤小鼠脾脏CD4+CD25+Foxp3+/CD4+的比值呈逐渐升高趋势。单次应用CTX抑制Treg的时间较短,而循环应用CTX能够延长对Treg的抑制,使其维持在相对较低的水平;循环应用CTX显著提高了荷瘤小鼠脾T淋巴细胞IFNγ的分泌水平。单次和循环应用CTX均未能延缓肿瘤的生长,两组小鼠均未见免疫性白斑及明显的化疗毒副反应。结论循环应用CTX能更加有效地调控Treg,从而促进DC对T淋巴细胞的抗原特异性激活,这将会提高DC疫苗的抗瘤效果。     

氨基系微胶囊包覆相变材料的研究进展

采用原位聚合法,对影响以脲醛树脂（UF）和三聚氰胺-甲醛树脂（MF）为囊壁的微胶囊相变材料性能的因素,得出以UF为囊壁时,宜采用反应温度为70℃,尿素和甲醛摩尔比为1：2,控制预聚阶段pH为8～9,酸化固化阶段pH为1．5～2;以MF为囊壁时,宜采用反应温度为70℃,三聚氰胺和甲醛摩尔比为1：（2．4-2．5）,控制预聚阶段pH为8-9,酸化固化阶段pH为3;然后选择氯化铵为pH调节剂并采用二次或三次调节,选择合适的乳化分散剂和乳化分散时间,可以获得优异的微胶囊性能。最后展望了氨基系囊壁的发展,并提出了目前面临的困难及急需解决的问题。     

聚乙二醇对聚乳酸/热塑性淀粉复合材料性能的影响

采用注塑法制备了聚乙二醇(PEG)改性的聚乳酸(PLA)/热塑性淀粉(TPS)复合材料,研究了PEG对PLA/TPS复合材料的加工流变性能、力学性能的影响,采用差示扫描量热(DSC)仪和扫描电子显微镜(SEM)进行微观结构分析并研究了加工工艺对复合材料性能的影响.结果表明,当PEG的质量分数为3%时,复合材料的力学性能最佳;DSC测试和SEM分析表明,PEG的加入提高了复合材料的塑性, 改善了其相容性.     

定形相变材料的制备方法

综述了定形相变材料各种制备方法的研究进展,介绍了定形相变材料的应用,总结了定形相变材料主要制备方法的发展方向.     

Effect of photostablizers on surface color and mechanical property of wood-flour/HDPE composites after weathering

The effects of photostabilizers of ultraviolet absorbers (UVA), hindered amine light stabilizer (HALS) and pigment on surface color change and mechanical properties of weathered wood-flour/ polyethylene (HDPE) composites were investigated. After being added UVA with high UV absorbance, the WPC exhibites better ability to resist color fading and mechanical property loss. High molecular weight HALS is found to be the most effective in controlling long term fading and yellowing changes. Pigments cover the composites for remaining the original color after weathering regardless of less contribution to mechanical property. Addition of photostabilizer and pigment together show great synergism in decreasing color fading and flexural property loss.     

紫外光固化聚氨酯的研究

介绍两种不同的聚氨酯预聚物合成工艺，并对它们涂层作紫外光辐射试验，试验得到的温度，辐射距离和固化时间等参数对生产优质涂料具有指导意义。     

The solids conveying mechanism for helically grooved single-screw extruders

A novel particle-size conveying model was established to examine the effects of the dimension relationships of the groove depth and particle size on the solids conveying mechanism of the helically grooved feed section. In the model, one or two shear interfaces were proposed based on the dimension relationships of the groove depth and particle size, and the solid-plug embedded in the groove and screw channel were divided into two or three layers by the shear interfaces to consider the solids conveying mechanism of each layer by the boundary condition equation for positive conveying. By the particle-size model, the effects of different dimension relationships on the transformation of solids conveying mechanisms between the friction-drag conveying and the positive conveying were discussed and compared with the on-line measuring experimental data. The results showed that the shear interfaces among the solids existed indeed and the dimension relationships determined the conveying mechanism and the throughput of helically grooved extruders, which was well confirmed by the excellent consistence between the predicted and measured data.     

人肌无力症骨骼肌纤维的超微病理改变

为研究肌无力症患者骨骼肌纤维的超微病理变化,采用超薄切片透射电镜观察分析法。电镜下可见到肌纤维局部肌节变形、粗细肌丝紊乱、明暗带不清、Z盘模糊、三联体减少、线粒体残损空泡化、糖原颗粒沉积、脂褐素增多以及肌纤维间质液化。骨骼肌原纤维及细胞器超微结构改变时肌无力超微病理诊断有重要意义。     

超高分子量聚乙烯微孔材料微观结构形态学表征

超高分子量聚乙烯（ＵＨＭＷ－ＰＥ）具有优异的综合性能,以ＵＨＭＷ－ＰＥ为基体的微孔材料在医药,环保,能源等领域具有非常广泛的应用前景。利用压汞法对不同ＵＨＭＷ－ＰＥ微孔材料的微观结构参数进行测定和比较,通过孔积分布函数、分形维数等方面的研究对ＵＨＭＷ－ＰＥ微孔材料的微观结构形态及其分布进行了初步的量化表征,并分析了不同参数所代表的物理意义。