教学课程资源库 更多>>

关键词： electrodeposition   neodymium   ionic liquid   physicochemical properties   cyclic voltammetry  

摘要： The density,conductivity,and viscosity of the 1,3-dimethyl-2-imidazolinone and lithium nitrate(DMILiNO_(3))solvated ionic liquid were measured as a function of ***,the electrochemical mechanism and electrodeposition of neodymium from the DMI-LiNO_(3) solvated ionic liquid were *** voltammetry results indicate that the electrochemical reduction of Nd(Ⅲ)is irreversible and proceeds via one-step with three-electron transfer,which is controlled by diffusion with a diffusion coefficient of 5.08×10^(-8) cm^(2)/*** X-ray spectrometry and X-ray photoelectron spectroscopy data confirm that the electrodeposit obtained after electrodeposition at-4 V(vs Ag)using the DMI-LiNO_(3)-Nd(CF_(3)SO_(3))_(3) solvated ionic liquid contains metallic neodymium.

关键词： 物理化学   六硝基六氮杂异伍兹烷(CL-20)   晶体形貌   分子动力学模拟  

摘要： 为了研究温度对六硝基六氮杂异伍兹烷(CL-20)在乙酸乙酯/三氯甲烷体系中结晶时晶体形貌的影响,采用分子动力学模拟方法,使用修正后附着能模型计算了CL-20晶体能量和晶习,对比了不同温度(293、303、313、323、333K)下CL-20晶体形貌模拟结果与实验结果。结果表明,温度可以显著改变CL-20晶体形貌;随着温度升高,CL-20晶体形貌趋于非球形化,293K下可以获得球形化程度更好的CL-20晶体;温度对不同晶面影响程度不同,(200)、(011)、(20-1)晶面生长易被温度影响,附着能绝对值较大,晶面生长速率快,在CL-20晶体表面面积占比减小,最终在CL-20晶体中无法保留;当温度为333K时,对(20-1)晶面的附着能影响较大,最终使该晶面在CL-20形貌中显露。

关键词： 课程思政   能力培养   知行合一   可持续发展  

摘要： 课程思政是素质教育的重要举措,本文对物理化学课程中体现能力培养与素质教育相融合的课程思政进行了理论分析,对思政元素进行了深入挖掘,发现物理化学课程能够培养师生的科学观、创新精神、家国情怀、民族自信、人文素养、责任担当。以本文作者参与编写的《物理化学》为依托,阐述了物理化学课程中能力培养与素质教育的切入点以及实施的手段和模式,指出了物理化学课程思政可持续发展的实践策略为“至简至趣、润物无声”。

关键词： Molten carbonate composite   Electrical conductivity   Capillary electrodes   Power output   Figure of merit   Thermo-electrochemical cell  

摘要： In molten carbonate thermo-electrochemical cells (thermocells), the dispersion of solid oxide in the molten electrolyte was found to improve conditions of thermoelectric energy conversion. However, stability of the solid oxide in eutectic (Li,Na)(2)CO3 electrolyte is crucial. The change in cell performance, due to compositional changes in the electrolyte mixture using various selected solid oxides, was studied. The solid oxides of Al2O3 or LiAlO2 were chemically reactive and no stable cell potential was observed when these compounds were added compared to when solid MgO or CeO2 were added. Also, a solid MgO-dispersion in the electrolyte delivered a larger Seebeck coefficient of -1.8 mV/K, favoring this oxide all together. The impact of the surface area of solid grains of MgO on the cell performance was investigated. From the electrical (sigma) and thermal (lambda) conductivity of the electrolyte mixture, along with the measured Seebeck coefficient (alpha(s)), the figure of merit (ZT) was determined. In addition to having a high stability, the dispersion of solid MgO with large surface area provided a better (sigma/lambda) ratio, and a larger alpha(s) (-1.8 mV/K) as well as ZT (1.1). (C) 2021 Elsevier Ltd. All rights reserved.

关键词： Starch   Cellulose nanocrystal   Oxidation   Film  

摘要： A cellulose nanocrystal based oxidation system is developed for oxidizing starch in the presence of NaClO, and provides an alternative and green method to improve the oxidizing degree of oxidized starch. The underlying mechanism for the oxidation was studied with confocal laser scanning microscopy. It was found that cellulose nanocrystal would penetrate into the starch microparticles and contribute to oxidation. The function of cellulose nanocrystal on the physicochemical properties of oxidized starch was investigated. With the incorporation of the oxidized starch into starch/polyvinyl alcohol/glyceryl composite films, the mechanical property and transparency of the films improved substantially. The highest oxidation level of starch was attained at 0.5 wt% cellulose nanocrystal dosage and the carboxylate content was 1.10%, the composite film showed the maximum transparency of 0.66 and highest contact angle of 102.0 degrees. Meanwhile, the best film was obtained with oxidized starch containing 1.0 wt% cellulose nanocrystal. Compared to native starch and TEMPO-oxidated starch, the cellulose nanocrystal-based oxidized starch improved the hydrophobicity of film more substanially. In conclusion, cellulose nanocrystal acts as prooxidant and reforcing agent in this starch-based composite film, which makes them promising materials in the preparation of novel composite materials.

关键词： 纳米颗粒   食物基质   相互作用   安全性  

摘要： 食品中纳米颗粒的增加使得其经口暴露于人体的可能性增大。因此,准确评估经口暴露纳米颗粒安全性十分重要。作者综述了食品中最常见纳米颗粒与食物基质、胃肠道的相互作用对纳米颗粒物理化学性质和生物效应影响,为准确评估纳米颗粒安全性提供参考。

关键词： 物理化学   降雨   冻胀   隧道渗漏水  

摘要： 近年来,我国公路隧道得到了蓬勃的发展。调查表明,渗漏水是隧道工程中常见的病害之一,因此隧道渗漏水病害研究成为热点问题。从物理化学作用、降雨以及冻胀三方面入手,通过建立物理化学数学模型,结合单纯形Monte Carlo法求解得出整个系统中反应动力随总自由能变化而变化,并且结合实例说明了统计参数方差较大时反应趋于平衡;并且根据渗漏量以及冻胀力的计算分析可以看出,渗漏量与地下水位和衬砌厚度存在紧密联系,当衬砌后的空洞缺陷尺寸较大时,冻胀力也增大。本研究为隧道渗漏水防治提供借鉴。

关键词： CoFe2O4 nanoparticles   Chitosan coating   Nanocubes Mossbauer spectroscopy   M-H curve fitting   Cytotoxicity  

摘要： In this work, single-phase cobalt ferrite nanocubes are successfully synthesized by hydrothermal method, and their surface is modified with biocompatible polymer chitosan. The effect of chitosan coating on the structure, morphology, magnetic, and cytotoxicity properties of CoFe2O4 nanoparticles is scientifically studied. XRD and XPS studies of bare and chitosan-coated samples confirmed the formation of the cubic spinel CoFe2O4 nanoparticles. HR-TEM revealed that the chitosan-coated CoFe2O4 nanoparticles are uniformly dispersed with a narrow particle size distribution and the average particle size obtained corresponds to that obtained from the XRD data. The bonding of chitosan onto the surface of CoFe2O4 nanoparticles is confirmed by both XPS and FT-IR spectroscopy. The room temperature M-H curve and the well-defined sextet patterns in the Mossbauer spectra confirm the ferromagnetic nature of the synthesized samples. The cation distributions obtained from the Mossbauer and X-ray photoelectron spectroscopy are well matched, which confirms the mixed spinel structure of the samples. Curve fitting using experimental M-H data can resolve the contribution of various magnetic phases such as ferromagnetic, superparamagnetic, and paramagnetic, which matches the magnetic properties obtained by Mossbauer analysis. Cytotoxicity studies have shown that the cytotoxicity of chitosan-coated CoFe2O4 nanoparticles is insignificant than bare samples.

关键词： 物理化学   PBL   教学改革与实践   工科化学  

摘要： 物理化学是理工科专业的重要专业基础课,以物理的方法和思维研究化学问题。对于工科专业的学生而言,普遍存在着理论难度大,公式多,课时有限的问题。学生在学习过程容易逐渐失去兴趣而影响后续专业课程的理解。基于问题的学习法(PBL)是以问题为驱动来开展的互动媒体支撑下的新型学习方法,让学生积极参与到课堂教学中来,有助于工科物理化学的教学效果提升。

关键词： Renewable energy   Biomass   Sustainable   Waste wood   Pig manure   Bio-asphalt  

摘要： Adoption of renewable energy sources such as biomass has been increasing worldwide. In this study, fast pyrolysis as an acceptable and viable method to get renewable bio-oil and biochar is used. Different temperatures and N-2 flow velocities were used in the fast pyrolysis process to evaluate the pyrolysis yield of biochar and bio-oil. The waste wood and pig manure were utilized to prepare biochar and bio-oil. X-ray fluorescence, X-ray diffraction, high-pressure liquid chromatograph, Micro confocal laser Raman spectrometer, Fourier transform infrared spectrometer, and dynamic shear rheometer were used to measure the chemical compositions, structure, and pyrolysis yield of biochar and bio-oil. The obtained results indicate that pyrolysis temperature increases the purity of inorganic oxide in biochar and N-2 flow velocity promotes the yield of carbon in biochar. The increase of N-2 flow velocity would increase the acid property of bio-oil and damage the products yield of bio-oil. It was also observed that biochar could remarkably alter the fundamental performances of petroleum asphalt including penetration, softening point, ductility, viscosity, and complex modulus. The most important is that the upgraded bio-oil can be used to replace partly or fully the petroleum asphalt which is a promising biomass application. (C) 2021 Elsevier B.V. All rights reserved.