检索结果-南通市图书馆

Organic Chemistry Frontiers 2022年第5期9卷 1254-1260页

作者： Houchen Wang Mingyue Chen Yuanyuan Zhu Yu Li Han Zhang Tiesheng Shi College of Chemistry Chemical Engineering and Materials ScienceZaozhuang UniversityZaozhuang 277160China

Monomers undergo supramolecular polymerizations via diverse pathways conferring pathway complexity;deciphering the complexity has been an intriguing and fundamental subject of various studies.

关键词： polymerization Thermodynamic complexity

Thermodynamic analysis and kinetic optimization of high-energy batteries based on multi-electron reactions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2020年第8期7卷 1367-1386页

作者： Yong-Xin Huang Feng Wu Ren-Jie Chen Beijing Key Laboratory of Environmental Science and Engineering School of Materials Science and Engineering Beijing Institute of Technology Advanced Technology Research Institute (Jinan) Beijing Institute of Technology Collaborative Innovation Center of Electric Vehicles in Beijing

Multi-electron reaction can be regarded as an effective way of building high-energy systems(>500 W h kg-1). However, some confusions hinder the development of multi-electron mechanisms, such as clear concept, complex reaction, material design and electrolyte optimization and full-cell fabrication.Therefore, this review discusses the basic theories and application bottlenecks of multi-electron mechanisms from the view of Thermodynamic and dynamic principles. In future, high-energy batteries,metal anodes and multi-electron cathodes are promising electrode materials with high theoretical capacity and high output voltage. While the primary issue for the multi-electron transfer process is sluggish kinetics,which may be caused by multiple ionic migration, large ionic radius, high reaction energy barrier, low electron conductivity, poor structural stability, etc., it is urgent that feasible and versatile modification methods are summarized and new inspiration proposed in order to break through kinetic constraints.Finally, the remaining challenges and future research directions are revealed in detail, involving the search for high-energy systems, compatibility of full cells, cost control, etc.

关键词： multi-electron reactions Thermodynamic kinetics high-energy density metal anodes

Separation of atropisomers by chiral liquid chromatography and Thermodynamic analysis of separation mechanism

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2017年第3期7卷 156-162页

作者： Ling Zhang Yue Hu Elizabeth Galella Frank P. Tomasella William P. Fish Chemical and Synthetic Development Bristol-Myers Squibb Co.New BrunswickNJ 08903USA Drug Product Science and Technology Bristol-Myers Squibb Co.New BrunswickNJ 08903USA

In the pharmaceutical industry, the analysis of atropisomers is of considerable interest from both scientific and regulatory perspectives. The compound of interest contains two stereogenic axes due to the hindered rotation around the single bonds connecting the aryl groups, which results in four potential configurational isomers(atropisomers). The separation of the four atropisomers was achieved on a derivatized β-cyclodextrin bonded stationary phase. Further investigation showed that low temperature conditions, including sample preparation(-70 °C), sample storage(-70 °C), and chromatographic separation(6 °C), were critical to preventing interconversion. LC-UV-laser polarimetric analysis identified peaks 1 and 2 as a pair of enantiomers and peaks3 and 4 as another. Thermodynamic analysis of the retention data indicated that the separation of the pairs of enantiomers is primarily enthalpy controlled as indicated by the positive slope of the van't Huff plot. The difference in absolute Δ(Δ H), ranged from 2.20 k J/mol to 2.42 k J/mol.

关键词： Atropisomer separation Chiral HPLC Thermodynamic parameters β-cyclodextrin stationary phase Chiral separation mechanism

Thermodynamic assessment of hydrogen production via solar thermochemical cycle based on MoO2/Mo by methane reduction

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2020年第1期14卷 71-80页

作者： Jiahui JIN Lei WANG Mingkai FU Xin LI Yuanwei LU College of Environmental and Energy Engineering Beijing University of TechnologyBeijing100022China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Inspired by the promising hydrogen production in the solar thermochemical(STC)cycle based on non-stoichiometric oxides and the operation temperature decreasing effect of methane reduction,a high-fuel-selectivity and CH4-introduced solar thermochemical cycle based on MoO2/Mo is studied.By performing HSC simulations,the energy upgradation and energy conversion potential under isothermal and non-isothermal operating conditions are compared.In the reduction step,MoO2:CH4=2 and 1020 K

关键词： MoO2/Mo based on solar thermochemical cycle methanothermal reduction isothermal and non-isothermal operation syngas and hydrogen production Thermodynamic analysis

Kinetic and Thermodynamic studies on partitioning of polychlorinated biphenyls (PCBs) between aqueous solution and modeled individual soil particle grain sizes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2019年第2期31卷 100-110页

作者： Gbadebo Clement Adeyinka Brenda Moodley School of Chemistry and Physics College of AgricultureEngineering and SciencesUniversity of KwaZulu-Natal

The significance of soil mineral properties and secondary environmental conditions such as pH, temperature, ionic strength and time in the partitioning of eight selected polychlorinated biphenyl(PCB) congeners between aqueous solution and soil particles with different grain sizes was studied. The mineral properties of a model soil sample were determined, and Brunauer–Emmett–Teller(BET) adsorption–desorption isotherms were employed to observe the surface characteristics of the individual modeled soil particles.Batch adsorption experiments were conducted to determine the sorption of PCBs onto soil particles of different sizes. The results revealed that the sorption of PCB congeners onto the soil was dependent on the amount of soil organic matter, surface area, and pore size distribution of the various individual soil particles. Low pH favored the sorption of PCBs,with maximum sorption occurring between pH 6.5 and 7.5 with an equilibration period of 8 hr.Changes in the ionic strength were found to be less significant. Low temperature favored the sorption of PCBs onto the soil compared to high temperatures. Thermodynamic studies showed that the partition coefficient(K_d) decreased with increasing temperature, and negative and low values of ΔH° indicated an exothermic physisorption process. The data generated is critical and will help in further understanding remediation and cleanup strategies for polluted water.

关键词： Partitioning PCBs Soil particle grain sizes Kinetics Thermodynamic studies pH

Kinetic and Thermodynamic investigations of CO2 gasification of coal chars prepared via conventional and microwave pyrolysis

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2020年第3期7卷 422-432页

作者： Peng Jiang Yang Meng Ziyao Lu Lan Xu Gang Yang Xiang Luo Kaiqi Shi Tao Wu Department of Chemical and Environmental Engineering The University of Nottingham Ningbo ChinaNingbo315100China Key Laboratory for Carbonaceous Wastes Processing and Process Intensification Research of Zhejiang Province The University of Nottingham Ningbo ChinaNingbo315100China

This study examined an isothermal CO2 gasification of four chars prepared via two different methods,i.e.,conventional and microwave-assisted pyrolysis,by the approach of thermogravimetric analysis.Physical,chemical,and structural behaviours of chars were examined using ultimate analysis,X-ray diffraction,and scanning electronic microscopy.Kinetic parameters were calculated by applying the shrinking unreacted core(SCM)and random pore(RPM)models.Moreover,char-CO2 gasification was further simulated by using Aspen Plus to investigate Thermodynamic performances in terms of syngas composition and cold gas efficiency(CGE).The microwave-induced char has the largest C/H mass ratio and most ordered carbon structure,but the smallest gasification reactivity.Kinetic analysis indicates that the RPM is better for describing both gasification conversion and reaction rates of the studied chars,and the activation energies and pre-exponential factors varied in the range of 78.45–194.72 kJ/mol and 3.15–102,231.99 s−1,respectively.In addition,a compensation effect was noted during gasification.Finally,the microwave-derived char exhibits better Thermodynamic performances than the conventional chars,with the highest CGE and CO molar concentration of 1.30%and 86.18%,respectively.Increasing the pyrolysis temperature,gasification temperature,and CO2-to-carbon molar ratio improved the CGE.

关键词： Coal char CO2 gasification Microwave pyrolysis Char properties Kinetics Thermodynamic

Thermodynamic nature of black holes in coexistence region

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 27-32页

作者： Shao-Wen Wei Yu-Xiao Liu Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu Provinceand Key Laboratory of Quantum Theory and Applications of Mo ELanzhou UniversityLanzhou 730000China Institute of Theoretical Physics&Research Center of Gravitation Lanzhou UniversityLanzhou 730000China

Studying the system state of coexistence regions will peek into to reveal microscopic interactions between different phases of a Thermodynamic system.However,there is no effective method to study Thermodynamic nature of the coexistence black hole regions for the failure of the equation of state.Aiming at these coexistence states,in this work,we develop a general approach by introducing two new ratio parameters.The first one is the ratio of the horizon radii of the saturated coexistence small and large black holes,and the second one measures that of the small black hole molecule number to the total molecule number.We demonstrate that the first parameter can serve as an order parameter to characterize the first-order phase transition.The study also shows that the black hole state in the coexistence region is uniquely determined by these two introduced parameters bounded between 0 and 1.These results are quite significant in the analytical study of phase transition and the microscopic nature of black hole in the coexistence regions.

关键词： transition. state. Thermodynamic

Experimental investigation and Thermodynamic modeling of the U-Nb system

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第22期81卷 229-235页

作者： Chuan Mo Wenlin Mo Peng Zhou BaiXue Bian Yong Du Tao Fa Pengguo Zhang Ruiwen Li Yanzhi Zhang Changsheng Zhang Yuanhua Xia Xiaolin Wang Institute of Materials China Academy of Engineering PhysicsJiangyou 621907China Hunan Provincial Key Defense Laboratory of High Temperature Wear-Resisting Materials and Preparation Technology Hunan University of Science and TechnologyXiangtan 411201China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Key Laboratory for Neutron Physics of Chinese Academy of Engineering Physics Institute of Nuclear Physics and ChemistryMianyang 621999China China Academy of Engineering Physics Mianyang 621900China

The phase equilibria and Thermodynamic properties of the U-Nb system were investigated through experiments and Thermodynamic modeling.In the experiments,a series of samples with different content of Nb were prepared by arc melting.The Nb content covers the entire composition range of the U-Nb binary system.After solidification,the samples were annealed and then analyzed by X-ray diffraction,scanning electron microscopy,energy dispersive X-ray spectroscopy,differential scanning calorimeter and neutron diffraction.The equilibrium phases,including γ1(U-rich bcc),αU,and γ2(U-depleted bcc),were determined in detail from the experimental characterization.The occurrence of the invariant reaction γ1→αU+γ2 was confirmed,and the reaction temperature and composition were accurately identified.Moreover,the experimental findings clarify the dispute between the Dwight and Terekhov theories regarding the phase region(i.e.,whether the phase region is αU+γ1 or βU+γ2).Furthermore,the U-Nb phase diagram was reassessed by incorporating the present experimental data and previously published reliable experimental data from the literature.A set of self-consistent Thermodynamic parameters were developed using CALPHAD(Calculation of phase diagrams),and the calculations reasonably agree with the experimental observations.

关键词： U-Nb alloy Monotectoid reaction Phase diagram Thermodynamic Modeling

Structure modification and recovery of amorphous Fe_(73.5)Si_(13.5)B_9Nb_3Cu_1 magnetic ribbons after autoclave treatment:SAXS and Thermodynamic analysis

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2019年第1期35卷 118-126页

作者： L.Y.Guo X.Wang K.C.Shen K.B.Kim S.Lan X.L.Wang W.M.Wang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of Education Shandong University Department of Nanotechnology and Advanced Materials Engineering Sejong University Herbert Gleiter Institute of Nanoscience School of Materials Science and Engineering Nanjing University of Science and Technology Department of Physics City University of Hong Kong

The structure, crystallization kinetics and magnetic property of as-quenched Fe_(73.5)Si_(13.5)B_9Nb_3Cu_1 amorphous ribbon(R0) as well as ribbons after autoclave treatment at 100°C and 150°C(R1 and R2) have been systematically studied by various techniques. With increasing autoclave treatment temperature,the measured structural, kinetic and magnetic parameters of samples increase firstly, i.e. R0 < R1; and then decrease or recover to the as-quenched sample, i.e. R2 < R1 or R2 ≈ R0. These results indicate that the SROs in R1 samples increased by transforming from fcc to bcc structure during the autoclave treatment and that the autoclave treatment can decrease the large radius(r_M) MRO(medium range order),but increase the small rMMRO. The measured structural, thermal and magnetic parameters of R2 sample have a tendency to recover toward as-quenched R0 sample. The thermal and magnetic parameters of samples after solely annealing treatment at higher temperature have no obvious recover phenomenon.The uneven actions of pressure and temperature in autoclave treatment may be helpful for us to search a new method to improve the magnetic properties of Fe-based glasses.

关键词： SAXS (small-angle X-ray scattering) Fe-based glass Thermodynamic Magnetic ribbon DSC (differential scanning calorimetry)

A simple calculation model for Thermodynamic equilibrium information between precipitation and matrix

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2018年第11期25卷 1156-1162页

作者： Yong Yang Tian-rui Li Tao Jia Zhao-dong Wang State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

A simple theoretical model was developed to predict equilibrium between precipitate and matrix in a multicomponent microalloyed steel.The solute concentration in the matrix,the composition and the volume fraction of the precipitated second phases,and the reduction in critical precipitation temperature of AlN induced by carbonitride were quantified by the proposed Thermodynamic model.The results predicted by the developed model and those by other approaches are in a good agreement.The main advantages of this model over the existing models are that the process of formulation derivation is simple and the model can be easily solved by a personal program.

关键词： AlN precipitation Carbonitride Thermodynamic model Phase equilibrium