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关键词： Micelles  

摘要： Stimuli-responsive block copolymer micelles can provide tailored properties for the efficient delivery of genetic material. In particular, temperature- and pH-responsive materials are of interest, since their physicochemical properties can be easily tailored to meet the requirements for successful gene delivery. Within this study, a stimuli-responsive micelle system for gene delivery was designed based on a diblock copolymer consisting of poly(N,N-diethylacrylamide) (PDEAm) as a temperature-responsive segment combined with poly(aminoethyl acrylamide) (PAEAm) as a pH-responsive, cationic segment. Upon temperature increase, the PDEAm block becomes hydrophobic due to its lower critical solution temperature (LCST), leading to micelle formation. Furthermore, the monomer 2-(pyridin-2-yldisulfanyl)ethyl acrylate (PDSAc) was incorporated into the temperature-responsive PDEAm building block enabling disulfide crosslinking of the formed micelle core to stabilize its structure regardless of temperature and dilution. The cloud points of the PDEAm block and the diblock copolymer were investigated by turbidimetry and fluorescence spectroscopy. The temperature-dependent formation of micelles was analyzed by dynamic light scattering (DLS) and elucidated in detail by an analytical ultracentrifuge (AUC), which provided detailed insights into the solution dynamics between polymers and assembled micelles as a function of temperature. Finally, the micelles were investigated for their applicability as gene delivery vectors by evaluation of cytotoxicity, pDNA binding, and transfection efficiency using HEK293T cells. The investigations showed that core-crosslinking resulted in a 13-fold increase in observed transfection efficiency. Our study presents a comprehensive investigation from polymer synthesis to an in-depth physicochemical characterization and biological application of a crosslinked micelle system including stimuli-responsive behavior.

关键词： 征订工作   物理化学学报   学术刊物   中国化学会   交叉学科   工程学院   学报编辑部   北京大学  

摘要： 2022年全国报刊杂志征订工作已经开始,敬请向贵单位推荐订阅2022年《物理化学学报》。《物理化学学报》是由中国科学技术协会主管,中国化学会和北京大学共同主办,北京大学化学与分子工程学院学报编辑部编辑出版的学术刊物。设有“通讯”、“展望”、“专论”、“综述”、“论文”等栏目,报导物理化学学科及交叉学科的基础研究及应用研究的创新成果。

关键词： 物理化学   石墨烯   纳米复合材料   溶胶-凝胶法   高氯酸铵(AP)   热分解  

摘要： 采用溶胶-凝胶法,以石墨烯为载体,通过超临界CO2干燥和高温煅烧制备出G/Ni/Fe_(2)O_(3)纳米复合材料,采用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、N2吸附-脱附法(BET)和差示扫描量热法(DSC)研究了纳米复合材料的结构、性能及其对高氯酸铵(AP)热分解催化性能的影响。结果表明,G/Ni/Fe_(2)O_(3)纳米复合材料具有多孔结构,比表面积为142m^(2)/g,总孔容积为0.55cm^(3)/g,Ni和Fe_(2)O_(3)粒子以纳米尺寸均匀分散在石墨烯片层上;当G/Ni/Fe_(2)O_(3)纳米复合材料的质量分数为9%时,AP的高温分解峰温由434.2℃降至347.9℃;分解放热量由593J/g增至1524J/g,归因于片层结构的GO可加速电子移动以及抑制纳米粒子团聚的双重作用,在高能固体推进剂中具有重要的应用潜力。

关键词： 物理化学   热力学   比较法   教学改革   热力学函数计算  

摘要： 《物理化学》课程中热力学部分内容非常重要,相似的概念、公式多,同学们容易混淆,以致不能灵活运用。本文用比较法将热力学知识点进行分类归纳总结,抓住核心,使复杂的问题简单化、清晰化,加深学生对知识点、尤其是众多公式的理解、记忆,促进各知识点间的融会贯通,从而培养学生的思维能力和创新能力,提高学生对物理化学的学习兴趣。

关键词： Ionic liquids   Hydroxyl-functionalized   Binary system   Excess properties   Redlich-Kister equation (R-K equation)  

摘要： Hydroxyl-functionalized ionic liquids 1-(2-hydroxyethyl)-3-methylimidazolium alanine was synthesized and characterized by H-1 NMR and C-13 NMR spectrum. And it was mixed with DMSO and water respectively by weight method over the entire concentration. The density, viscosity, surface tension and refractive indices of the binary mixture were measured in the temperature range from 288.15 K to 333.15 K. Then volume properties and excess data were calculated and fitted. According to Redlich-Kister equation, the relationship between excess molar volume, viscosity deviation and the molar fraction of solute were fitted. Using the excess properties, the influence of the interaction between IL and solvents (DMSO/water) were analyzed. By comparing with the systems of the different ILs in the same solvents, the above-mentioned properties were discussed. (C) 2021 Elsevier B.V. All rights reserved.

关键词： 实验教学   物理化学   留白策略  

摘要： 针对物理化学实验教学中存在的问题,根据学生的认知规律,在实验教学中每个环节,采用留白教学策略,通过教学设计,把发现的权利还给学生,在充分体现教师主导作用的同时实现学生主体地位的回归。

关键词： 物理化学   课程思政   教学研究  

摘要： 在建设新时代具有中国特色社会主义的大背景下,高校思想政治教育刻不容缓,思政教育应融入到每一门课程中。本文研究了课程思政实施的基本内容,探讨了《物理化学》课程中的思政元素及教育目标,改革了教学方式方法和考核方法。

关键词： 意义建构学习   金课   物理化学  

摘要： 借鉴意义建构学习理论,融合"金课"本质和特征,文章提出意义建构学习的物理化学"金课",并介绍了意义建构学习的物理化学课程设计过程,包括新知识、新技能与学生原有认知结构的"跨度"分析,"小步距"同化新知识和新技能,认知结构在新情境中的迁移和应用;在此基础上,提出开展意义建构学习的开放课堂、程序性知识和策略性知识的高阶课堂、元认知教学的高阶课堂教学,以及采用包含课堂评价、低阶评价和高阶评价的意义建构学习的物理化学"金课"三维评价策略。

关键词： 物理化学   含能材料   LLM-105   机械球磨法   纳米化  

摘要： 为改善2,6-二氨基-3,5-二硝基吡嗪-1-氧化物(LLM-105)的形貌/尺寸,扩大其在高能钝感配方设计、制备及装药中的实用性,采用机械球磨法批量化制备了粒径在100nm以内的LLM-105颗粒;采用扫描电子显微镜(SEM)和纳米激光粒度仪观测了纳米LLM-105的形貌和粒径分布;采用X射线衍射仪(XRD)和傅里叶变换红外光谱仪(FT-IR)分析了其分子结构和晶型;采用热重-差示量热扫描仪(TG-DSC)研究了其热性能的变化;最后对其撞击感度、摩擦感度和静电火花感度进行了评估。结果表明,纳米LLM-105的平均粒径约为94.7nm,形貌呈类球形;机械球磨法未改变LLM-105的分子结构和晶型;纳米LLM-105热分解峰温较原料粗颗粒提前了13~18℃,表观活化能提高了12.8kJ/mol;撞击感度降低了约66.1%,摩擦感度升高了约6.0%,静电火花感度降低了约4.5%。

关键词： Brewing water   Chinese teas   Sensory attributes   Physicochemical properties  

摘要： The effects of brewing water on the sensory attributes and physicochemical properties of tea infusions made from Chinese teas were investigated. The tea infusions brewed in water with higher pH and total dissolved solids (TDS), generally had a darker color and lower overall sensory acceptability. Moreover, those infusions had less catechins, particularly galloylated-catechins, and lower antioxidant capacity. The teas with less fermentation contained more galloylated-catechins and had higher antioxidant capacity, but were much more susceptible to high mineral brewing water. Green tea was proved to be the most susceptible one, whereas dark tea the most stable one. Green tea infusions prepared with higher pH/TDS water were more rapidly oxidized, resulting in a darker color due to polymerization of catechins, when exposed to the air. These findings suggested that low mineral brewing water was better for Chinese tea, both from the sensory and health benefit perspectives.