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关键词： 物理化学学报   学术刊物   中国化学会   工程学院   编辑部编辑   同行评议   征稿简则   网络版  

摘要： 《物理化学学报》是由中国科学技术协会主管、中国化学会与北京大学共同主办、北京大学化学与分子工程学院物理化学学报编辑部编辑出版的学术刊物,月刊,向国内外公开发行,刊载物理化学领域具有原创性的基础研究和应用研究的成果。遵循国际通行的办刊惯例,实行主编、副主编负责制;所有刊出稿件都必须经过同行评议。从1997年起被SCI收录。2020年网络版首次在线发布平均时间53天。

关键词： Kaolinite   Acid activated kaolinite   Base activated kaolinite   Nickel nanoparticles  

摘要： The influence of HCl and NaOH activation on kaolinite to synthesize acid and base activated kaolinite (AAK and BAK) as catalyst supports for nickel oxalate precursor synthesized via oxalic acid functionalization (OAF) was explored in the study. For comparison, another catalyst was synthesized via incorporation of nickel nitrate salt into the activated supports and the catalysts were calcined at 700 degrees C. The characterization results confirmed that while acid treatment reduced the crystallinity of Kaol, base treatment transformed Kaol into sodalite-zeolite according to the XRD and FESEM results. The Ni nanoparticle (NP) sizes on nickel supported on AAK (Ni/AAK700) were nine times larger than Ni particle sizes on nickel supported on BAK (Ni/BAK-700) which itself is 1.42 times smaller than the Ni NP in oxalic acid-functionalized Ni supported on BAK (NiOL/BAK-700). The XPS Ni2p peak of Ni/BAK-700 was observed to shift towards higher binding energy signifying a higher degree of metalsupport interaction with increased H-2 reduction difficulty. A reversed phenomenon was observed for NiOL/BAK700. The samples basicity followed the order Ni/BAK-700 > NiOL/BAK-700 > NiOL/BAK-800 > Ni/AAK700, while the acidity followed the reverse. These results provide insights into modified Kaol supported Ni catalysis for various applications based on the required physicochemical properties.

关键词： Oxygen-enriched gasification   Biomass   Syngas   Biochar   Lithium ion batteries (LIBs)  

摘要： Syngas from conventional biomass gasification has low calorific value, low H-2/CO ratio, and high tar content. Oxygen and steam gasification are effective ways to improve the quality of syngas. Gas-carbon co-generation is possible due to the lower temperature at the bottom of the downdraft fixed-bed gasifier. Oxygen-enriched gasification of biomass is investigated in this work. The H-2 content in the syngas increased from 34 v% to 45 v% when steam was added. The physicochemical characteristics of the activation carbon (AC) are determined by the Brunauer-Emmett-Teller (BET), Raman, Fourier transform infrared spectrometry (FTIR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscope (TEM). In addition, the AC from the activation of carbon-rich production used as anode in lithium ion batteries (LIBs) is attempted. The BET of the AC(o) and AC(o-s) is 1715.32 m(2) g(-1) and 1409.02 m(2) g(-1), respectively. The biomass-derived carbon material had less graphitic crystalline structure, less functional groups and graphene-like porous structure after activation. At the current density of 100 mA g(-1), a reversible lithium storage capacity of 327 mAh g(-1) for a carbon-based electrode is obtained. This research provides a new roadmap for high-value-added products from the thermo-chemical conversion of biomass. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： 熵变计算   可逆过程   状态函数  

摘要： 系统熵变可用于判定过程的方向性,在热力学体系中占有重要地位,是教学的一个重点.同时熵变计算问题还具有多样性和灵活性的特点,是教学的一个难点.分别以可逆过程和不可逆过程熵变的计算、理想气体混合过程熵变的计算、体系和环境熵变的计算、循环过程熵变的计算这四类具体熵变计算问题为例,阐述如何通过灵活运用热力学第一、二定律的有关知识(尤其是跟熵有关的三个基本知识)来处理熵变计算问题.

关键词： 教学改革   量子化学   无机化学   物理化学   反应势能面   反应速率常数  

摘要： 化学热力学、动力学是无机化学和物理化学课程的重要内容,然而这部分知识抽象难懂。我们尝试在教学中将计算模拟与化学热力学、动力学知识点深度融合,帮助学生加深对知识的理解。在课堂上通过向学生模拟演示甲醛解离反应的化学热力学和动力学过程,将抽象知识直观、可视化。根据学生反馈发现后续课堂学生的积极性、参与度都有很大的提高。

关键词： Ultrasonic-assisted solvent extraction   Pressing   Supercritical fluid extraction   Individual polyphenol   Free radical scavenging capacity  

摘要： A research was performed to determine and compare the physicochemical properties, chemical compositions and in vitro antioxidant activities of Paeonia lactiflora Pall seed oils with ultrasonic-assisted solvent extraction, pressing and supercritical fluid extraction. Paeonia lactiflora Pall seed oil contained a high percentage of polyunsaturated fatty acids and monounsaturated fatty acids, especially oleic (31.62-32.88%) and alpha-linolenic acids (37.55-39.95%). The beneficial multiple dietary phytochemicals (tocopherol, phytosterols and squalene) and in vitro antioxidant activity were significantly influenced by the hull and processing method (P<0.05). However, higher tocopherol (596.67-738.76 mg/kg) and phytosterols (5775.01-6055.62 mg/kg) contents were found in supercritical fluid extraction oils. Additionally, ten individual polyphenols were quantified, and significantly influenced by the hull and processing method (P<0.05), with the content of benzoic acid and several individual flavonoids being the higher. According to the results, pressing might be the best process for extracting oil with a high number of polyphenols.

关键词： 物理化学   互动式教学   教学改革  

摘要： 当前各高校的教学计划中,物理化学课程的学时一再被压缩,如何在有限的学时内让学生掌握物理化学的精髓则是对众多教学一线工作者的巨大挑战。所以,改变传统、陈旧的“填鸭式”教学模式,提高学生自主学习的能力,激发生的创新思维和动手能力,论文以互动式教学模式为主要手段,探索出了适合本校学生的学习方法,总结为三点:教学过程中创造互动;学时安排上补充互动;教学测评上促进互动。

关键词： 物理化学   互联网+   改革  

摘要： 《物理化学》课程是化学专业的重要基础课程,概念抽象、理论性强。针对课程情况,采用网络教学资源和网络教学平台辅助学生进行课前预习,帮助教师了解任课班级学情进而开展有针对性的教学。课后可以进行线上答题、批改和师生互动,有助于解决学生学习过程中遇到的各种问题,提高学生的表达能力,激发学生的学习积极性,提升教学质量。

关键词： Curcuminoids   Antioxidant activity   Nanostructured lipid carriers   Skin penetration   Stability  

摘要： Four formulations of nanostructured lipid carriers (NLC) loaded with curcuminoids where prepared, testing two types of solid lipids (Compritol (R) 888 ATO and Precirol (R) ATO 5) and two kinds of stabilizers (poloxamer 407 and polysorbate 80). Particle size values between 111 and 214 nm and polydispersity indices < 0.3 were registered, with low Z potential values due to the nonionic character of the stabilizers. The results showed that the type of surfactant had an impact on the in vitro release rate and on the ex vivo skin permeation capability of curcuminoids. Polysorbate 80 delayed the release, but favors the transport of a higher amount of curcuminoids to the receptor solution during the ex vivo permeation studies than the systems with poloxamer 407. Confocal microscopy confirmed that all systems favored the penetration of curcuminoids to deeper layers of the skin and in a greater amount than curcuminoids in solution. Exposure of the systems to intense radiation caused the degradation of curcuminoids, without loss of antioxidant activity, confirming that the degradation products also function as antioxidants. The NLC prepared can be valuable carriers to enhance the penetration of curcuminoids into the skin, to treat different disorders and skin diseases.

关键词： 物理化学   类酶催化   光谱   氮掺杂石墨烯  

摘要： 通过改进的Hummer法合成氧化石墨烯(GO),然后以氨水为氮源,经过一步水热法温和地制备了具有丰富纳米孔的氮掺杂还原氧化石墨烯(N-RGO)筛网状片层。N-RGO显示出高效的类酶催化活性,可以催化氧化多种有机化合物发生显色反应,如3,3',5,5'-四甲基联苯胺(TMB)、邻苯二胺(OPD)、2,2'-叠氮基-二(3-乙基苯并噻唑啉磺酸)(ABTS)等。利用透射电子显微镜(TEM)、Raman光谱和X射线光电子能谱(XPS)对其进行系统表征。通过平行试验证明N-RGO催化氧化TMB是氧气参与的高效4电子转移反应过程。催化性能测试表明N-RGO相对辣根过氧化物酶(HPR)表现出了更强的耐受性,在较宽范围内(温度25~85℃,pH值4~7,NaCl浓度0~100 mmol·L^-1)均具有类酶催化活性。通过Michaelis-Menten模型的拟合可知,当GO浓度为5 mg·mL^-1时合成的N-RGO表现出较低的米氏常数(Km≈0.2 mmol·L^-1)和较高的反应速率(vmax≈0.07μmol·L^-1)。