检索结果-南通市图书馆

Nano Research 2024年第6期17卷 5742-5752页

作者： Zhonghao wang Wei Tang Jialin Liu gang Zhou School of Science Hubei University of TechnologyWuhan 430068China

To elucidate the synergistic effect of dual-atom catalysts(DACs)at the microscopic level,we propose and construct a prototype heteronuclear system,CuNi/TiO_(2),in which the two elements of a pair have significantly different d electron-donating abilities,as a piece in the *** density functional theory calculations,we investigate charge-dependent configurations of Cu-Ni dimers anchored on TiO_(2)by the mixing of individual constituent *** d electron-donating ability determines deposition sequence and position of transition metal atoms on oxides,establishing dimer pattern and metal-support *** interaction between Cu and Ni,beyond the coordination environment,predominately contributes to the synergistic effect.A complex adsorption-reduction behavior of H species on CuNi/TiO_(2)is *** reaction mechanism and catalytic activity of CuNi/TiO_(2)for hydrogen production are *** room temperature and high H coverages,CuNi/TiO_(2)shows better performance and efficiency than Ni1/TiO_(2).Our findings provide a new understanding of the synergistic effect on structure-activity relationships of supported dimers,which would be beneficial in the future design of various DACs or even atomically dispersed metal catalysts.

关键词： dual-atom catalysts heteronuclear/homonuclear dimers synergistic effect density functional theory hydrogen production

Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 747-762页

作者： Hanxiao guo Peifeng GAO Xingzhe wang Key Laboratory of Mechanics on Western Disaster and Environment of Ministry of Education Key Laboratory of Special Function Materials and Structure Design of Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting *** respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic *** numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally ***,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake *** approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic *** then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic *** results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and *** proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets.

关键词： epoxy-impregnated high-temperature superconducting(HTS)magnet multi-scale method global homogenization(GH) local refinement(LR) multi-field analysis

维普期刊数据库

A universal strategy of multi-objective active learning to accelerate the discovery of organic electrode molecules

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第11期67卷 3681-3687页

作者： Jiayi Du Jun guo Wei Liu Ziwei Li gang Huang Xinbo Zhang State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied Chemistry Chinese Academy of Sciences School of Applied Chemistry and Engineering University of Science and Technology of China School of Materials Science and Engineering Changchun University of Science and Technology

Organic electrode molecules hold significant potential as the next generation of cathode materials for Li-ion batteries. In this study, we have introduced a multi-objective active learning framework that leverages Bayesian optimization and non-dominated sorting genetic algorithms-Ⅱ. This framework enables the selection of organic molecules characterized by high theoretical energy density and low gap(LUMO-HOMO)(LUMO, lowest unoccupied molecular orbital; HOMO, highest occupied molecular orbital). Remarkably, after only two cycles of active learning, the determination of coefficient can reach 0.962 for theoretical energy density and 0.920 for the gap with a modest dataset of 300 molecules, showcasing superior predictive capabilities. The 2,3,5,6-tetrafluorocyclohexa-2,5-diene-1,4-dione, selected by non-dominated sorting genetic algorithms-Ⅱ, has been successfully applied to Li-ion batteries as cathode materials, demonstrating a high capacity of 288 m Ah g-1and a long cycle life of 1,000 cycles. This outcome underscores the high reliability of our framework. Furthermore, we have also validated the universality and transferability of our framework by applying it to two additional databases, the QM9 and OMEAD. When the training dataset of the model includes at least 500 molecules, the determination of coefficient essentially reaches approximately0.900 for four targets: gap, reduction potential, LUMO, and HOMO. Therefore, the universal framework in our work provides innovative insights applicable to other domains to expedite the screening process for target materials.

关键词： organic electrode molecules Li-ion batteries active learning multi-objective Bayesian optimization

Dynamic characteristics of multi-span spinning beams with elastic constraints under an axial compressive force

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 295-310页

作者： Xiaodong guo Zhu SU Lifeng wang State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A theoretical model for the multi-span spinning beams with elastic constraints under an axial compressive force is *** displacement and bending angle functions are represented through an improved Fourier series,which ensures the continuity of the derivative at the boundary and enhances the *** exact characteristic equations of the multi-span spinning beams with elastic constraints under an axial compressive force are derived by the Lagrange *** efficiency and accuracy of the present method are validated in comparison with the finite element method(FEM)and other *** effects of the boundary spring stiffness,the number of spans,the spinning velocity,and the axial compressive force on the dynamic characteristics of the multi-span spinning beams are *** results show that the present method can freely simulate any boundary constraints without modifying the solution *** elastic range of linear springs is larger than that of torsion springs,and it is not affected by the number of *** an increase in the axial compressive force,the attenuation rate of the natural frequency of a spinning beam with a large number of spans becomes larger,while the attenuation rate with an elastic boundary is lower than that under a classic simply supported boundary.

关键词： multi-span spinning beam elastic constraint improved Fourier series free vibration semi-analytical solution

维普期刊数据库

Metal-N_(4)model single‐atom catalyst with electroneutral quadri‐pyridine macrocyclic ligand for CO_(2)electroreduction

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第8期6卷 122-133页

作者： Jian‐Zhao Peng Yin‐Long Li Yao‐Ti Cheng Fu‐Zhi Li Bo Cao Qing wang Xian Yue guo‐Tao Lai Yang‐gang wang Jun Gu Department of Chemistry Southern University of Science and TechnologyShenzhenGuangdongChina Institute for Catalysis Hokkaido UniversitySapporoJapan

Metal–N–C single‐atom catalysts,mostly prepared from pyrolysis of metalorganic precursors,are widely used in heterogeneous *** metal sites with diverse local structures coexist in this type of material and it is challenging to characterize the local structure,a reliable structure–property relationship is difficult to *** macrocyclic complexes adsorbed on carbon support are well‐defined models to mimic the singleatom ***–N_(4)site with four electroneutral pyridine‐type ligands embedded in a graphene layer is the most commonly proposed structure of the active site of single‐atom catalysts,but its molecular counterpart has not been *** this work,we synthesized the conjugated macrocyclic complexes with a metal center(Co,Fe,or Ni)coordinated with four electroneutral pyridinic ligands as model catalysts for CO_(2)*** comparison,the complexes with anionic quadri‐pyridine macrocyclic ligand were also *** Co complex with the electroneutral ligand expressed a turnover frequency of CO formation more than an order of magnitude higher than that of the Co complex with the anionic *** ab initio molecular dynamics simulations based on the well‐defined structures of the model catalysts indicate that the Co complex with the electroneutral ligand possesses a stronger ability to mediate electron transfer from carbon to CO_(2).

关键词： ab initio molecular dynamics CO_(2)reduction electrocatalysis model catalyst single‐atom catalyst

Generating empathetic responses through emotion tracking and constraint guidance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第2期18卷 243-245页

作者： Jing LI Donghong HAN Zhishuai guo Baiyou QIAO gang WU School of Computer Science and Engineering Northeastern UniversityShenyang 110000China Key Laboratory of Intelligent Computing in Medical Image(Ministry of Education) Northeastern UniversityShenyang 110000China Neusoft Corporation Shenyang 110000China

1 Introduction Empathy is an essential human trait,which reflects the ability of understanding and reflecting on the thoughts and feelings of *** empathetic dialogue system can improve user's experience and establishlong-termhuman-machine *** speaker's emotions and predict response's emotions are necessary steps in empathetic dialogue generation.

关键词： interaction. constraint steps

Genomic insights into the origin and evolution of spelt(Triticum spelta L.)as a valuable gene pool for modern wheat breeding

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plant Communications 2024年第5期5卷 75-90页

作者： Yongfa wang Zihao wang Yongming Chen Tianyu Lan Xiaobo wang gang Liu Mingming Xin Zhaorong Hu Yingyin Yao Zhongfu Ni Qixin Sun Weilong guo Huiru Peng Frontiers Science Center for Molecular Design Breeding Key Laboratory of Crop Heterosis and UtilizationBeijing Key Laboratory of Crop Genetic ImprovementChina Agricultural UniversityBeijing 100193China Institute for Plant Genetics Heinrich Heine University40225 DusseldorfGermany Sanya Institute of China Agricultural University Sanya 572025China

Spelt(Triticum aestivum ***)is an important wheat subspecies mainly cultivated in Europe before the 20th century that has contributed to modern wheat breeding as a valuable genetic ***,relatively little is known about the origins and maintenance of spelt ***,using resequencing data from 416 worldwide wheat accessions,including representative spelt wheat,we demonstrate that Eu-ropean spelt emerged when primitive hexaploid wheat spread to the west and hybridized with pre-settled domesticated emmer,the putative maternal *** introgression regions from domesticated emmer confer spelt’s primitive morphological characters used for species taxonomy,such as tenacious glumes and laterﬂ*** propose a haplotype-based"spelt index"to identify spelt-type wheat vari-eties and to quantify utilization of the spelt gene pool in modern wheat *** study reveals the ge-netic basis for the establishment of the spelt wheat subspecies in a specific ecological niche and the vital role of the spelt gene pool as a unique germplasm resource in modern wheat breeding.

关键词： wheat spelt interspecific hybridization gene pool modern wheat breeding

Composition operators on weighted Bergman spaces induced by doubling weights

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 Mathematics 2024年第7期67卷 1571-1598页

作者： Xin guo Maofa wang School of Mathematics and Statistics Wuhan UniversityWuhan430072China

Given a doubling weightωon the unit disk D,let A_(ω)^(p) be the space of all the holomorphic functions f,where∥f∥A_(ω)^(p):=(∫_(D)|f(z)|_(p)ω(z)dA(z))^(1/p)<∞.We completely characterize the topological connectedness of the set of composition operators on A_(ω)^(p).As an application,we construct an interesting example which reveals that two composition operators on A_(α)^(p) in the same path component may fail to have a compact difference and give a negative answer to the Shapiro-Sundberg question in the(standard)weighted Bergman *** addition,we completely describe the central compactness of any finite linear combinations of composition operators on A_(ω)^(p) in three terms:a Julia-Carathéodory-type function-theoretic characterization,a power-type characterization,and a Carleson-type measure-theoretic characterization.

关键词： composition operator linear combination linearly connected weighted Bergman space doubling weight

维普期刊数据库

Thermodynamic and experimental study of high-temperature roasting of blast furnace gas ash for recovery of metallic zinc and iron

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第1期31卷 108-120页

作者： Zi-han wang Jing guo Han-jie guo Bin Li School of Metallurgical Engineering University of Science and Technology BeijingBeijing100083China School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina

A high-temperature reduction roasting method was used to achieve metallic iron and zinc recovery from blast furnace gas ash(BFA).The reduction processes for Zn-containing and Fe-containing oxides were analyzed in detail by using ther-modynamic equilibrium calculation and the principle of minimum free *** results showed that the main reaction in the system is the reduction of ZnFe_(2)_(4)and iron *** the full temperature range,iron oxides were more easily reduced than zinc *** of the amount of CO contained in the system,the reduction of ZnO to Zn was difficult to proceed below the boiling point(906℃)of *** the reduction temperature is below 906℃,the reduction process of zinc ferrate was ZnFe_(2)_(4)→ZnO;when the reduction temperature is above 906℃,its reduction process becomed ZnFe_(2)_(4)→ZnO→Zn(g).The metallization and dezincification rates of the BFA gradually increased with increasing reaction *** the C/O ratio increased,the metallization and dezincification rates first increased and then *** effect of reduction time on BFA reduction was similar to that of reaction temperature.

关键词： Blast furnace gas ash Thermodynamics Zinc removal Iron reduction High-temperature reduction roasting Integrated utilization

Improving mathematical model of burden distribution and correcting chute angle to cope with fluctuation of stock line

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 Iron and Steel Research International 2024年第2期31卷 342-356页

作者： Jian-sheng Chen Wen-guo Liu Hao guo wang Ding Qing-guo Xue Jing-song wang Hai-bin Zuo State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China MCC Capital Engineering&Research Incorporation Limited Beijing100176China Hunan Valin Xiangtan Iron and Steel Co. Ltd.Xiangtan411101HunanChina

Accurate evaluations of the burden distribution are of critical importance to stabilize the operation of blast *** mathematical model and discrete element method(DEM)are two attractive methods for predicting burden *** on DEM,the initial velocities of the pellet,sinter,and coke were calculated,and the velocity attenuations of the above three particles between the burden and the chute were *** initial velocity and velocity attenuation were applied to a mathematical model for improving the ***,based on the improved model,a scheme for rectifying the chute angles was proposed to address the fluctuation of the stock line and maintain a stable burden *** validity of the scheme was confirmed via a stable burden distribution under different stock *** mathematical model has been successfully applied to evaluate the online burden distribution and cope with the fluctuation of the stock line.

关键词： Burden distribution Mathematical model Discrete element method Velocity attenuation Stock line fluctuation