翔安文教园文献资源共建共享初探

厦门翔安文教园分布着厦门大学翔安校区和厦门海洋学院等多座高校,园内各院校图书馆各自为政,缺乏协调与合作。文章提出翔安文教园开展文献资源共建共享的构想,探讨翔安文教园各院校图书馆提高文献利用率和文献保障能力的策略

小槐花的化学成分研究

目的:系统研究中药小槐花中的化学成分。方法:利用大孔树脂,Sephadex LH-20,ODS及正相硅胶柱等色谱手段进行分离,通过多种波谱学数据分析进行化合物的结构鉴定。结果:从小槐花60%乙醇提取物中分离得到15个化合物,经结构鉴定分别为豆甾醇(1),β-谷甾醇(2),柠檬酚(3),黄槿酮A(4),异柠檬酚(5),kenusanone I(6),neophellamuretin(7),清酒缸酚(8),古柯三醇(9),黄槿酮D(10),山柰酚(11),8-prenylquercetin(12),leachianone G(13),5,7,4'-三羟基-二氢黄酮醇(14),4H-1-benzopyran-4-one,2-(3,4-dihydroxyphenyl)-2,3-dihydro-3,5,7-trihydroxy-8-(3-methyl-2-butenyl)-,(2R-trans)-(9CI)(15)。结论:除化合物8外,所有化合物均为从该种植物中首次分离得到

STUDY ON CRYSTALLIZATION BEHAVIOR of PET/POL YGLYCOL BLEND

应用光学解偏振光法、温度-形变法和dSC法研究了PET/聚乙二醇(Pgl)共混物的结晶行为。结果表明,聚乙二醇是PET优良的结晶促进剂,随着聚乙二醇含量的增加,共混物的结晶速率明显提高,dSC热谱图上的熔融结晶温度(T_(MC))和冷却结晶温度T_(CC)差比纯PET增大了31℃,扩大了结晶温度范围,同时T_g下降,使共混物的注射模塑温度可望有较大的降低。The crystallization behavior of PET/polyglycol blend is studied by depolarized light intensity .temperature-distortion and DSC.The results showed that polyglycol was an excellent accelerator For the crystallization of PET.The crystallization rate of the blend was increased rapidly with increasing the concentration of polyglycol- The diFFerence between melt crystallization temperature (Tmc) and cold crystallization temperature (Tec)of PET/polyglycol blend in DSC was 31℃ higher than that of pure PET.The temperature range of crystallization was widened and Tg lowered slopingly.It could be expected that the injection moulding temperature of PET could be greatly lowered by adding polyglycol

中国西部典型地区土地利用变化对比分析

作者选择中国西部长城沿线农牧交错带的陕西省榆林市榆阳区、西北干旱区河西走廊的甘肃省酒泉市肃州区和西南四川盆地丘陵区的四川省德阳市中江县为3个典型研究区域,对20世纪80年代以来的农村社会经济统计资料、土地概查、土地详查、遥感图像判读以及136个典型农户调查进行分析发现:土地利用的变化既受自然的地球生物物理驱动力的制约,又受社会、经济、技术和历史等因素的影响,具有很强的综合性和地域性。西部地区具有悠久的土地开发历史,其土地覆盖类型多种多样。由于其特殊的自然地理特征和社会、经济、政治等驱动因素的复杂多变,本区的土地覆盖发生了很大的变化,这些变化同农业、林业、牧业等与土地资源利用有关的产业发展以及城市化和土地退化等可持续发展问题密切相关。影响西部地区土地利用变化的驱动因素主要是人口增长与城镇化、固定资产投入与工矿交通产业发展、经济结构调整、科技发展和政策管理等人文因素

Preparation and Development of Multilayer Coextrusion Composite Film by Biaxially Orientation

高性能薄壁化和多层复合是当前塑料包装薄膜的发展趋势。双向拉伸多层共挤复合薄膜不仅可以满足包装行业对薄膜多功能性的要求,还具有减薄功能,可大幅度减; 少同类塑料薄膜的用量,降低生产成本。文中分别介绍拉伸取向和多层共挤关键技术、商业化薄膜生产设备和几种主要的薄膜产品,如双向拉伸聚丙烯(BOPP); 薄膜、双向拉伸聚酯(BOPET)薄膜、双向拉伸聚酰胺(BOPA)薄膜、双向拉伸聚乳酸(BOPLA)薄膜和双向拉伸聚乙烯(BOPE)薄膜,着重讨论; 了 BOPE薄膜研究现状及未来展望。Oriented plastic films for packaging applications are industrially; produced in large quantities. In order to meet the demands on modern; flexible packaging, biaxially oriented tentering and multilayer; coexcusion have been developed. It is required that the prepared plastic; films should fulfill a protective function, and allow product design in; line with economic and environmental aspects. In this review, the; orientation technology and multilayer coexcusion were introduced. Some; types of film such as biaxially oriented polypropylene (BOPP), biaxially; oriented polyester (BOPET), biaxially oriented polyamide; (BOPA),biaxially oriented polylactic acid (BOPLA),and biaxially oriented; polyethylene (BOPE) films were also outlined. Finally, the present; situation and future prospect of BOPE film were emphatically discussed.福建省阻燃与防火材料技术重大研发平台; 厦门市科技计划项目; 国家自然科学基金资助项