聚丙烯与超支化聚酯共混物的非等温动力学(英文)

Polypropylene (PP) with different contents of the second generation hyperbranched polyester (HBP) is prepared by melt blending method. The non-isothermal crystallization kinetics of PP and PP/HBP blends is investigated under differential scanning calorimetry (DSC). The Mo equation is used to analyze the DSC data. The results show that the Mo theory is suitable for crystal ization kinetics of the blends. Fast cooling rate is not good for crys-tallizing and nucleating. The values of half crystal ization time (t1/2), crystal ization enthalpy (ΔHc) and temper-ature range (ΔT) of PP/HBP blends decrease when HBP is added. The required cooling rate of PP is higher than that of PP/HBP blends in order to reach the same relative crystal inity. Crystallization rate increases with the ad-dition of HBP. The crystallization rate reaches a maximum when the content of HBP is 5%. In addition, the activa-tion energies of PP and PP/HBP blends are calculated by Kissinger equation, revealing that the content of HBP has a little effect on the crystallization activation energy.     

Non-isothermal crystallization kinetics of polypropylene and hyperbranched polyester blends☆

Polypropylene (PP) with different contents of the second generation hyperbranched polyester (HBP) is prepared by melt blending method. The non-isothermal crystallization kinetics of PP and PP/HBP blend...     

大型机械设备融资租赁应用研究

大型机械设备是许多企业生产经营的核心,融资租赁作为一种新型的金融工具,可实现融资、融物的有机结合,逐渐成为企业添置大型设备的主流方式之一。首先,分析了融资租赁的特点;其次,分析了融资租赁应用过程中存在的风险;最后,提出了企业应用融资租赁的对策建议。     

马尔文激光粒度分析仪Mastersizer 2000及其应用

介绍了激光粒度分析仪Mastersizer 2000的工作原理,并以聚丙烯催化剂载体粒径分布测量为例,介绍了Mastersizer 2000的测试方法、参数选择及注意事项,最后对其应用现状进行了综述。     

综合性考核在本科《药理学》课程中的应用

为了培养学生自主学习能力、提升药理学学习兴趣和信心,在本科药学专业中推行综合性考核方法,内容包括:学生考勤、小测验、病例分析、实践技能、期末考试。对药理学考试成绩进行比较分析。结果综合性考核方式学生及格率、平均分均较传统考核方式提高,学生对这一考核方法接受度较高,为其进一步的推广奠定了基础。     

土方调配优化中的问题及其解决方法

在土方调配中,对土方调配的求解方法通常采用线性规划法中的"表上作业法"进行改进,采用"表上两侧夹逼作业法"。这种方法可以提高工作效率,减少检验等步骤,可一次性得到更为准确、高效的最优解。     

基于大数据的城市交通态势推演与综合评估关键技术及应用

城市交通态势推演和评估技术是城市交通治理的核心量化分析技术.随着城市交通治理综合化、精细化和智能化要求的提高,传统依托小样本数据调查与分析,建立集计经验模型进行多方案比选评估的方法和技术,已难以适应新时期城市交通治理要求.本项目历时十余年,在国家自然科学基金等国家级、省部级课题支持下,突破了基于多源大数据的个体出行活动链全过程全方式融合感知、城市交通演化态势可靠推演与敏捷预测、城市交通精细化治理综合评估等关键技术,建立了面向城市交通精细化治理的个体出行活动链模型和大规模路网实时在线推演模型,构建了大数据综合评估体系,支撑了城市交通精细化治理科学量化分析与评估.项目应用超过1000个项目,推广至成都、重庆、苏州、湛江、南昌、长春、兰州等100多座城市,影响了全国约2亿人的交通出行.     

游船旅游活动对洱海水环境的影响分析

根据洱海现有游船的特点和数量,基于游船产生的含油废水、固体废弃物、生活污水,分析了游船旅游活动对洱海环境的影响及其特点,并在此基础上提出了洱海游船污染防治措施。     

A New and Practical Synthetic Method for the Synthesis of 6-O-Methyl-scutellarein: One Metabolite of Scutellarin in Vivo

Scutellarin (1) has been used for the treatment of angina pectoris, cerebral infarction and coronary heart disease with a large market share in China. Pharmacokinetic studies on scutellarin showed that scutellarin (1) is readily converted into its metabolites in vivo. In this paper, a new and practical synthetic method for the synthesis of 6-O-methyl-scutellarein (3) (one metabolite of scutellarin in vivo) is reported. The benzyl bromide was firstly used to selectively replace the acetyl group at C-7 in 7, and was then used to protect the hydroxy groups at C-4'' in 10, 6-O-methyl-scutellarein (3) is obtained in high yield through these methods.     

Unveiling the Mode of Action of Two Antibacterial Tanshinone Derivatives

In this study, 2-(N-pyrrolidine-alkyl) tanshinones bearing pyrrolidine groups were synthesized and the antibacterial mechanism was explored. These derivatives selectively elicited antibacterial activity against Gram-positive bacteria. Moreover, their antibacterial activities were time-, concentration-dependent and persistent. It appeared that Fenton-mediated hydroxyl radicals were involved, and the disruption of cell membranes was observed. This study indicates that 2-(N-pyrrolidine-alkyl) tanshinones might be potential candidates as antibacterial agents.