氢氧化镁表面改性及其在LDPE中的应用

采用表面改性剂对氢氧化镁颗粒进行表面改性，探讨了表面改性剂种类、用量对氢氧化镁颗粒表面性质的影响．结果表明：当多磷酸酯的质量分数为1％时，氢氧化镁的物理性质趋于最佳．进而将改性氢氧化镁与聚乙烯共混，其拉伸强度明显提高．     

二维装配图的快递交点排序裁剪算法

提出一个任意多边形的快速交点排序线裁剪算法,该算法简单快捷,效率高,并将其成功用于工程装配图的二维消隐。解决了大多数算法将凹多边形裁剪分解为凸多边形处理存在计算时间长、难度大等问题。     

模糊综合评价法在企业R＆D能力评价中的应用

依据影响企业R＆D能力的诸多不确定因素，运用模糊综合评价法从整体上评价各个影响因素，综合评价企业R＆D能力。     

硫酸浓度对纳米级SO4^2-／TiO2固体超强酸的影响

用锐钛型纳米TiO2制备了纳米级SO4^2-／TiO2固体超强酸，分析了硫酸浓度不同时其比表面积、失重率、红外光谱及催化活性的不同。当硫酸浓度为1．0mol／L时，它在450～900℃的失重率为3．3％，比表面积为105．2m^2／g，对乙酸和丁醇酯化反应的酯化率达到98．4％。玻璃球负载纳米级SO4^2-／TiO2固体超强酸的重复使用性能好，在乙酸和丁醇的酯化反应中重复使用9次后的酯化率才由初次的99．3％变为84．9％。     

A preliminary study of crassulacean acid metabolism (CAM) in the endangered aquatic quillwortIsoetes sinensis Palmer in China

Isoetes sinensis Palmer (Isoetaceae) is an aquatic or amphibious plant that is critically endangered in China. Previous studies have revealed the crassulacean acid metabolism (CAM)-like photosynthetic pathway occurs commonly in submerged leaves in genusIsoetes. Water chemistry parameters and the titratable acidity content of the plant extract were measured from samples obtained in the early morning (7∶00) and late afternoon (15∶00) from twoI. sinensis populations in China. One population occurs in the eulittoral zone of a freshwater tidal river at low elevation (134 m) and another occurs in a densely vegetated, high elevation (1 100 m) alpine shallow pool. Significant differences in pH and titratable acidity of the plant extract were detected between the morning and afternoon samples. These changes are associated with diurnal changes in water chemistry. Our results provide the first evidence for the existence of the CAM pathway in the East Asian endemicIsoetes sinensis Palmer. The magnitude of fluctuations in the titratable acidity of the plant extract may be correlated with the severe carbon limitation imposed on the plants by its aquatic habitat. Foundation item: Supported by the State Key Basic Research and Development Plan (G2000046805) Biography:Pang Xin-an (1974-), male, Master candidate, research direction: conservation biology.     

会计学专业实践性教学模式的探讨

知识经济时代 ,对会计人员的素质要求越来越高。文章主要探讨如何加强会计专业实践性教学环节 ,寻求有效的实践性教学模式 ,从而培养出具有熟练会计核算能力、利用会计资料进行会计监督、参与企业经营管理预测和决策能力的会计人才     

Effects of hyaluronic acid－chitosan－gelatin complex on the apoptosis and cell cycle of L929 cells

With the development in the field of tissue engineering, the interaction between biomaterials and cells has been deeply studied. Viewing the cells seeded on the surface of materials as an organic whole, cell cycle and apoptosis are analyzed to deepen the study of cell compatibility on biomaterials, while cell proliferation and differentiation are studied at the same time. In this paper, hyaluronic acid is incorporated into the chitosan-gelatin system. Propidium iodide (PI) was used in cell cycle analysis and the double-staining of cells with annexin-V and PI was applied in cell apoptosis analysis. The results show that incorporated hyaluronic acid shortens the adaptation period of cells on the material surface, and then cells enter the normal cell cycle quickly. In addition, added hyaluronic acid inhibits cell apoptosis triggered by the membranes. Therefore, hyaluronic acid improves the cell compatibility of chitosan-gelatin system and benefits the design of biomimetic materials.     

乳状液膜法提取废水中柠檬酸传质模型的研究

在探讨乳状液膜法提取废水中柠檬酸的基础上，建立了恒界面状况下的非稳态平板传质模型，经过合理假设，推导出易于求解的拟稳态平板传质模型；利用恒界面条件下的实验数据，拟合了拟稳态平板传质模型。     

巴比妥酸对B-Z振荡反应的影响及其分析应用

研究了巴比妥酸对B Z振荡反应的影响,结果表明,巴比妥酸的加入明显改变了振荡体系的周期和振幅,且巴比妥酸的浓度与振荡周期改变值ΔT及振幅改变值ΔA均呈现良好的线性关系,线性范围为6 4×10-7～3 1×10-3mol/L,相关系数分别为0 9921和0 9954.对振荡体系的扰动机理进行了初步探讨.     

新疆北鲵肌肉蛋白质、氨基酸、无机元素及食物组成分析

本报道了新疆北鲵肌肉蛋白质含量为19．08％，氨基酸17种，无机元素有Ca等6种，成幼体食物组成中以石蚕及腺状介虫为主．