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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   人物专访   学报编辑部  

摘要： 2021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2021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“亮点”“当期推荐”“通讯”“展望”“专论”“综述”“论文”“人物专访”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： 物理化学实验   实验改进   教学方法  

摘要： 在物理化学实验室的运行中有不少值得改进和探讨的地方。文章从实验误差、仪器精度、强度性质实验、线上线下教学和实验室效率等五个方面指出物理化学实验室运行中存在的问题,并给出了可行的解决方案,希望对物理化学实验的教学有所助益。

关键词： 生成热   密度泛函   等键反应  

摘要： 热力学在《物理化学》中占有很大比重,鉴于有些化合物的生成热难以通过实验测得。本文以苯酚类硝基衍生物及硝基苯为对象,在密度泛函DFT-B3LYP/6-31G水平下利用等键反应法,对14种有实验值生成热的化合物进行了预测,并与实验值进行关联对比,结果表明计算求得的数值与实验值非常接近。

关键词： Resveratrol  

摘要： The novel zein-propylene glycol alginate (PGA) -tea saponin (TS) ternary complex nanoparticles were fabricated to deliver resveratrol. TS was firstly introduced to modulate the functional attributes, microstructure, molecular interactions and gastrointestinal digestion of the complex nanoparticles. The size of zein-PGA-TS complex nanoparticles was between 281.9 and 309.7 nm. In the presence of TS, the encapsulation efficiency of resveratrol was significantly elevated from 58.43% to 85.58%. The environmental stability of resveratrol was improved through entrapping into the complex nanoparticles with the rise in TS proportion. Multiple spectroscopic methods revealed that TS altered the micro-environment and secondary structure of the protein. Hydrogen bonds, hydrophobic effects and electrostatic interactions contributed to the formation of complex nanoparticles. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) patterns showed the amorphous nature of the encapsulated resveratrol. Field emission scanning electron microscopy (FE-SEM) confirmed the globular shape of the nanoparticles and their different aggregation states were dependent on the particle compositions. Moreover, the zein-PGA-TS complex nanoparticles exhibited the best sustained release in the small intestine when the mass ratio of zein to TS was 5 : 1 (23.20% in the stomach and 63.11% in the small intestine). These findings indicated the influence of TS on the properties and applications of the protein-polysaccharide complexes, which provided a new insight into the development of novel food grade nanoparticles with desirable stability and digestion behaviour.

关键词： 工程教育   物理化学实验   教法改革   线上线下混合教学  

摘要： 通过分析我校化工专业物理化学实验教学采用的仿真平台的应用结论,总结线上教学的优劣势,结合线下教学实践的经验和教训,提出了从教学计划、教学模式、教学互动、评价方式等方面进行的线上线下相结合的物理化学实验改革思路,开启了化工教育信息化背景下,我校实验教学教法改革和化工工程教育人才培养模式转变的新征程。

关键词： Solid-state reaction   Structural study   Raman   FTIR   Optic properties   Electric and dielectric properties  

摘要： Barium titanate is a very attractive perovskite given its ferroelectric, piezoelectric and dielectric properties. These can be further improved by the substitution of barium and titanium by different elements. Introducing both rare earths and/or metals in this compound enhances its optical and electrical properties, thus making it a multifunctional material suitable for many different applications. In the present work, the compound Ba0.91Er0.1/3Ca0.04Ti0.92Sn0.08O3 is prepared by solid state reaction and its structural, morphological, thermal optical and electrical properties are investigated in detail by X ray diffraction, scanning electron microscopy, differential scanning calorimetric, absorption spectroscopy and impedance spectroscopy respectively. Scanning electron microscopy shows that the material is composed by a major polycrystalline phase with micrometric grain size. Two-phase transitions at 448 K and 572 K are deduced from thermal and electrical measurements. The optical measurements indicate that both erbium and tin are well introduced in the structure, which is confirmed by energy dispersive spectroscopy, and affects the vibrational modes. a. c. and d. c. electrical measurements show that, depending on the measurement temperature range, conduction mechanism is either a non-overlapping small polaron tunneling or a correlated barrier hopping model. . Moreover, dielectric measurements prove a high dielectric constant and identify a phase transition from the ferroelectric phase to paraelectric one which is in agreement with literature. Such substitution improves the compound properties and makes it suitable for different devices.

关键词： 物理化学   重要公式   记忆方法  

摘要： 物理化学是一门逻辑性强、公式繁多的化学基础理论课。结合列举实例,总结了联想记忆法、类比记忆法、化繁为简记忆法、归类记忆法和逻辑关联记忆法等多种方法在物理化学重要公式记忆中的应用,使学生通过应用这些方法提高记忆物理化学公式的效率。

关键词： Enzymes   Glomalin   Heavy metals   Phosphorus   Soil   Soil aggregate stability  

摘要： Soil enzymes play a key role in the circulation of nutrients and the functioning of the ecosystem. The aim of the study was to assess how the tree species of urban agglomerations affect soil quality and enzymatic activity (dehydrogenases DEH, catalase CAT, alkaline AlP and acid AcP phosphatase, protease PR, beta-glucosidase GLU, and urease UR). To this end, soil samples were taken from beneath nine park trees. The risk of soil contamination by selected heavy metals (Pb, Ni, Cd) was also investigated against the background of the selected physicochemical properties. Enzyme activity results were used to calculate multi-parametric indices of soil quality: availability factor (AF), enzymatic pH indicator (AlP/AcP), biological index of fertility (BIF), geometric mean (GMea), alternation index (Al3), biochemical soil activity (BA16 and BA17). The results showed statistically significant differences in physicochemical and enzymatic properties of soil depending on tree species. Correlation analysis showed that the content of total organic carbon (TOC), total nirogen (TN), total phosphorus (TP) and humus (OM) in soil significantly influenced the activity of the studied enzymes and glomalin content. AF coefficient values (1.84%- 18.19%) suggest that the bioavailability of available phosphorus (AP) was sufficient. The Pb, Ni, Cd content results were found to be low and did not exceed the permissible concentrations. DEH, CAT and AlP activity were highest under common hawthorn, and AcP, GLU and PR under northern white cedar. The calculated enzymatic indicators proved to be a sensitive and accurate indicator of the dynamics of changes taking place in the city park soil. Based on the results, an attempt can be made to assess the planning of sustainable development of studied areas of urban parks. (C) 2020 Elsevier B.V. All rights reserved.

关键词： boron cluster compounds   carbonyl derivatives   nucleophilic addition  

摘要： The nucleophilic addition of the monocarbonyl derivative of the closo-dodecaborate anion [B12H11CO](-) with N- and O-nucleophiles has been studied. This process proceeds under mild conditions in high yield. Not only primary and secondary amines but also tertiary ones can be added. The resulting borylated derivatives are thermally unstable, and the C-O and C-N bonds split upon heating forming the initial [B12H11CO](-) anion. In an acidic medium in aqueous solutions, borylated derivatives hydrolize forming the carboxylate derivative of general formula [B12H11COOH](-).

关键词： chapatti   black wheat   blue wheat   purple wheat   anthocyanin   antioxidant  

摘要： Biofortified colored wheat (black, blue, and purple) is rich in anthocyanins and phenolic acid compounds that impart positive physiological effects in humans. A large proportion of wheat is consumed in the form of Chapatti in Asian countries. The effect of chapatti cooking on the proximate composition, bioactive compounds (anthocyanins and phenolics), and antioxidant activities of these wheat varieties were checked in this study. Apart from acceptable sensory parameters, good taste, and soft texture of chapatti, biofortified colored wheat chapatti and flour had higher dietary fibers, protein content, and lower carbohydrate content. Higher soluble and insoluble phenolic compounds, anthocyanin content, and antioxidant activity were in the order of black > blue > purple > white. Chapatti making has reduced their antioxidant activity and anthocyanin content in comparison to flour. Moreover, the reduction in antioxidant activity is less as compared to the decrease in anthocyanin content. Our results suggest that colored wheat can be a better alternative to normal wheat for preparing chapatti as it would have additional health-promoting activities.