检索结果-南通市图书馆

Microstructure evolution and mechanical properties of brazing joint for ultra-thin-walled Inconel 718 considering grain size effect and brazing temperature

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第2期37卷 541-556页

作者： Rui ZHAO Yueshuai sONG Hui KANG Min wan school of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

The systematic investigation of the mechanical properties and microstructure evolution process of ultra-thin-walled Inconel 718 capillary brazing joints is of great significance because of the exceptionally high demands on its *** achieve this objective,this study investigates the impact of three distinct brazing temperatures and five typical grain sizes on the brazed joints’mechanical properties and microstructure evolution *** evolution analysis was conducted based on Electron Back scatter Diffraction(EBsD),scanning Electron Microscopy(sEM),X-Ray Diffraction(XRD),High-Resolution Transmission Electron Microscopy(HRTEM),and Focused Ion Beam(FIB).Besides,the mechanical properties and fracture behavior were studied based on the uniaxial tension tests and in-situ tension *** findings reveal that the brazing joint’s strength is higher for the fine-grain capillary than the coarse-grain one,primarily due to the formation of a dense branch structure composed of G-phase in the brazing *** effects of grain size,such as pinning and splitting,are amplified at higher brazing ***,micro-cracks initiate around brittle intermetallic compounds and propagate through the eutectic zone,leading to a cleavage fracture *** fracture stress of fine-grain specimens is higher than that of coarse-grain due to the complex micro-crack ***,this study contributes significantly to the literature by highlighting the crucial impact of grain size on the brazing properties of ultra-thin-walled Inconel 718 structures.

关键词： EYWORDs Ultra-thin-walled structure Brazing Inconel 718 Grain size effect Brazing temperature

A spleen Tyrosine Kinase’s sky in Neuronal Degeneration

在线全文

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2024年第2期40卷 273-276页

作者： wan-Yun Zhang sen Lin Department of Neurology Xinqiao HospitalThe Second Afliated HospitalArmy Medical UniversityChongqing 400042China Chongqing Institute for Brain and Intelligence Guangyang Bay LaboratoryChongqing 400064China

With the growing elderly population,neurodegenerative disorders like Alzheimer's disease(AD)are emerging as a significant public health *** is widely acknowledged in the scientific community that the accumulation of neurotoxic aggregates,such as amyloid beta(Aβ),within the central nervous system is a major factor in the development of these ***,human genome-wide association studies have identified mutations in microglial receptors that may be linked to a number of neurodegenerative diseases[1].

关键词： Aβ spleen Alzheimer

Dynamic Hypergraph Modeling and Robustness Analysis for sIoT

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & sciences 2024年第9期140卷 3017-3034页

作者： Yue wan Nan Jiang Ziyu Liu school of Information Engineering East China Jiaotong UniversityNanchang330013China

The social Internet of Things(sIoT)integrates the Internet of Things(IoT)and social networks,taking into account the social attributes of objects and diversifying the relationship between humans and objects,which overcomes the limitations of the IoT’s focus on associations between *** Intelligence(AI)technology is rapidly *** is critical to build trustworthy and transparent systems,especially with system security issues coming to the *** paper emphasizes the social attributes of objects and uses hypergraphs to model the diverse entities and relationships in sIoT,aiming to build an sIoT hypergraph generation model to explore the complex interactions between entities in the context of intelligent *** hypergraph generation models impose too many constraints and fail to capture more details of real *** contrast,this paper proposes a hypergraph generation model that evolves dynamically over time,where only the number of nodes is *** combines node wandering with a forest fire model and uses two different methods to control the size of the *** new nodes are added,the model can promptly reflect changes in entities and relationships within *** results exhibit that our model can effectively replicate the topological structure of real-world *** also evaluate the vulnerability of the hypergraph under different attack strategies,which provides theoretical support for building a more robust intelligent sIoT hypergraph model and lays the foundation for building safer and more reliable systems in the future.

关键词： Large-scale artificial intelligence social Internet of Things hypernetwork robustness analysis

study of the pressure transient behavior of directional wells considering the effect of non-uniform flux distribution

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum science 2024年第3期21卷 1765-1779页

作者： Yan-Zhong Liang Bai-Lu Teng wan-Jing Luo school of Energy Resources China University of Geosciences(Beijing)Beijing100083China

During the production,the fluid in the vicinity of the directional well enters the wellbore with different rates,leading to non-uniform flux distribution along the directional ***,in all existing studies,it is oversimplified to a uniform flux distribution,which can result in inaccurate results for field ***,this paper proposes a semi-analytical model of a directional well based on the assumption of non-uniform flux ***,the direction well is discretized into a carefully chosen series of linear sources,such that the complex well trajectory can be captured and the nonuniform flux distribution along the wellbore can be considered to model the three-dimensional flow *** using the finite difference method,we can obtain the numerical solutions of the transient flow within the *** the aid of Green's function method,we can obtain the analytical solutions of the transient flow from the matrix to the *** complete flow behavior of a directional well is perfectly represented by coupling the above two types of transient ***,on the basis of the proposed model,we conduct a comprehensive analysis of the pressure transient behavior of a directional *** computation results show that the flux variation along the direction well has a significant effect on pressure *** addition,the directional well in an infinite reservoir may exhibit the following flow regimes:wellbore afterflow,transition flow,inclined radial flow,elliptical flow,horizontal linear flow,and horizontal radial *** horizontal linear flow can be observed only if the formation thickness is much smaller than the well ***,a dip region that appears on the pressure derivative curve indicates the three-dimensional flow behavior near the wellbore.

关键词： Directional well Pressure transient behavior semi-analytical model Non-uniform flux

Upper-rim-modified thioether thiacalix[4]arene used for liquid-liquid extraction of Au(Ⅲ)and Pd(Ⅱ)in hydrochloric acid medium

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第2期66卷 110-118页

作者： sheng wan Rong Xie Jianhong Fan Kewen Tang Department of Chemistry and Chemical Engineering Hunan Institute of Science and TechnologyYueyang 414006China

Gold(Au)and palladium(Pd)play an increasing role in the production and human life;Therefore,it is of great significance to study their recovery.A 5,11,17,23-tetra-ethylthio-25,26,27,28-tetra-hydroxyl thiacalix[4]arene(TCAET)was synthesized specifically for the capture of Au(Ⅲ)and Pd(Ⅱ)from HCl medium by liquid-liquid *** a 0.1 mol·L^(-1)HCl medium,the transfer of Au(Ⅲ)and Pd(Ⅱ)from the aqueous phase to the organic phase was highly efficient,with a transfer ratio of 100%for Au(Ⅲ)and 98%for Pd(Ⅱ).Furthermore,the extraction equilibrium time for Au(Ⅲ)was just 5 ***'s method data demonstrated that TCAET formed complexes with Au(Ⅲ)and Pd(Ⅱ)in a ratio of 2:3 and 1:1,respectively,during the extraction *** showed high selectivity toward Pd(Ⅱ)and Au(Ⅲ)over other competing metal ***,both Au(Ⅲ)and Pd(Ⅱ)could be successfully stripped from the loaded organic phases with a 1.0 mol·L^(-1)thiourea in 0.5 mol·L^(-1)HCl and 0.5 mol·L^(-1)thiourea in 0.5 mol·L^(-1)HCl,*** obtained from five consecutive extraction-stripping cycles showed good reusability of TCAET toward Au(Ⅲ)and Pd(Ⅱ)*** conclusion can provide a certain reference for thiacalixarene in the recovery of precious metal species.

关键词： Thiacalixarene Upper-rim modification Liquid-liquid extraction Precious metal Thioether

Recent Advances in Mechanistic Understanding of Metal-Free Carbon Thermocatalysis and Electrocatalysis with Model Molecules

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第7期16卷 74-97页

作者： Wei Guo Linhui Yu Ling Tang Yan wan Yangming Lin CAs Key Laboratory of Design and Assembly of Functional Nanostructures Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002People’s Republic of China Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstituteChinese Academy of SciencesXiamen 361021People’s Republic of China state Key Laboratory of structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002People’s Republic of China Institute of Urban Environment Chinese Academy of SciencesXiamen 361021People’s Republic of China

Metal-free carbon,as the most representative heterogeneous metal-free catalysts,have received considerable interests in electro-and thermo-catalytic reac-tions due to their impressive performance and *** the past decade,well-designed carbon catalysts with tunable structures and heteroatom groups coupled with various characterization techniques have proposed numerous reaction ***,active sites,key intermediate species,precise structure-activity relationships and dynamic evolution processes of carbon catalysts are still rife with controversies due to the monotony and limitation of used experimental *** this Review,we sum-marize the extensive efforts on model catalysts since the 2000s,particularly in the past decade,to overcome the influences of material and structure limitations in metal-free carbon *** both nanomolecule model and bulk model,the real contribution of each alien species,defect and edge configuration to a series of fundamentally important reactions,such as thermocatalytic reactions,electrocatalytic reactions,were systematically *** with in situ techniques,isotope labeling and size control,the detailed reaction mechanisms,the precise 2D structure-activity relationships and the rate-determining steps were revealed at a molecular ***,the outlook of model carbon catalysis has also been proposed in this work.

关键词： Metal-free carbon catalysts Model catalyst Electrocatalysis Active site Reaction mechanisms

Identification of the optimal doping position of hetero-atoms in chalcogen-doped Fe-N-C catalysts for oxygen reduction reaction

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第6期89卷 99-108页

作者： Weihao Liu Huanhuan He Qingtao Liu Xin wan Jianglan shui school of Materials science and Engineering Beihang UniversityBeijing100191China school of space and Environment Beihang UniversityBeijing102206China Tianmushan Laboratory Hangzhou310023China

The excellent oxygen reduction reaction(ORR)activity of Fe–N–C catalysts in acidic media makes them potential for low-cost proton exchange membrane fuel *** recent years,it has been shown that heteroatoms(B,O,s,P,Cl,F,etc.)can be used as electron-withdrawing groups to modulate the planar structure and electron distribution of the Fe–Nx active sites to achieve simultaneous improvement of catalytic activity and ***,the optimal location of the heteroatoms remains ***,taking chalcogen heteroatoms(s and se)as an example,we control the doping positions and investigate their effect on the ORR performance of the Fe–N–C *** first coordination shell of the iron single atom is identified as the optimal doping *** optimized catalysts Fe–N_(3)se_(1)/NC and Fe–N_(3)se_(1)/NC demonstrate improved activity and stability in both half cells and fuel *** work provides insights into the enhancement mechanism of heteroatom doping in single-atom catalysts.

关键词： Oxygen reduction reaction Fe-N-C catalysts Hetero-atom doping Doping position Enhancement mechanism

Effect of coenzyme Q10 supplementation on post-vitrification mouse embryo development

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian pacific Journal of Reproduction 2024年第3期13卷 126-132页

作者： Anisa-Annur s.wan-Hafizah WJ Nor-Ashikin MNK Muhammad-Zaki R Faculty of Pharmacy and Health sciences Royal College of Medicine PerakUniversiti Kuala Lumpur30450 IpohPerakMalaysia Maternofetal and Embryo Research Group Faculty of MedicineUniversiti Teknologi MARASelangor BranchSungai Buloh Campus47000 Sungai BulohSelangorMalaysia

Objective:To investigate the effects of coenzyme Q10(CoQ10)supplementation on post-vitrification embryo development and gross ***:Balb/c mouse embryos were cultured in potassium simplex optimised medium(KsOM)with varying CoQ10 concentrations[0(control),20,40,and 60μM].The most effective CoQ10 concentration(40μM)was selected for subsequent post-vitrification morphology *** were randomly divided into four groups:Group A(non-vitrified without CoQ10),Group B(non-vitrified with CoQ10),Group C(vitrified without CoQ10),and Group D(vitrified with CoQ10),followed by vitrification at the 8-cell *** rates and development until the blastocyst stage were evaluated through morphological examinations using AsEBIR's system,distinguishing normal and abnormal ***:supplementation of 40μM CoQ10 significantly increased blastocyst formation(95%)compared to the control group(92%),20μM(62%),and 60μM(56%)(Psignificant increase in blastocyst formation(92%)compared to Group C(82%)(Pssessments indicated superior embryo quality in Group B over Group D during the cleavage stage,morula,and blastocyst(Psions:CoQ10 supplementation exhibits promising potential to enhance preimplantation embryo development,increase blastocyst formation rates,and improve embryo quality *** offers a promising approach to mitigate oxidative stress on embryos,potentially improving overall assisted reproductive technology outcomes.

关键词： Coenzyme Q10 Antioxidant Embryo development Vitrification Morphology Assisted reproductive technology

A Quarterly High RFM Mining Algorithm for Big Data Management

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第9期80卷 4341-4360页

作者： Cuiwei Peng Jiahui Chen shicheng wan Guotao Xu school of International Education Guangdong University of TechnologyGuangzhou510006China school of Computer science and Technology Guangdong University of TechnologyGuangzhou510006China Business Administration South China University of TechnologyGuangzhou510641China Guangzhou Institute of Technology Xidian UniversityGuangzhou710071China

In today’s highly competitive retail industry,offline stores face increasing pressure on *** hope to improve their ability in shelf management with the help of big data *** this,on-shelf availability is an essential indicator of shelf data management and closely relates to customer purchase ***(recency,frequency,andmonetary)patternmining is a powerful tool to evaluate the value of customer ***,the existing RFM patternmining algorithms do not consider the quarterly nature of goods,resulting in unreasonable shelf availability and difficulty in *** solve this problem,we propose a quarterly RFM mining algorithmfor On-shelf products named *** algorithmmines the high recency,high frequency,and high monetary patterns and considers the period of the on-shelf goods in quarterly *** conducted experiments using two real datasets for numerical and graphical analysis to prove the algorithm’s *** with the state-of-the-art RFM mining algorithm,our algorithm can identify more patterns and performs well in terms of precision,recall,and F1-score,with the recall rate nearing 100%.Also,the novel algorithm operates with significantly shorter running times and more stable memory usage than existing mining ***,we analyze the sales trends of products in different quarters and seasonal *** analysis assists businesses in maintaining reasonable on-shelf availability and achieving greater profitability.

关键词： Data mining recency pattern high-utility itemset RFM pattern mining on-shelf management