检索结果-南通市图书馆

Effect of heat treatment on microstructure and mechanical properties of selective laser-melted PH13-8Mo stainless steel

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4期31卷 945-955页

作者： Yuan Zhang xiang Liu chang-jun Wang chang Liu School of Material Science and Engineering Kunming University of Science and TechnologyKunming 650093YunnanChina Central Iron&Steel Research Institute Co. Ltd.Beijing 100081China

PH13-8Mo stainless steel powder with high sphericity and well fluidity was prepared by the plasma rotating electrode process.The formed parts with ultra-high purity were manufactured by selective laser melting.The tensile and impact mechanical properties of the printed parts under three heat treatment regimes were compared to those without heat treatment.The microstructure,grain orientation and phase composition were characterized by electron-backscatter diffraction,X-ray diffraction and transmission electron microscopy.The characterization results reveal that the addition of heat treatment makes the grains enlarge,and after different heat treatments,the average grain size from 1.51μm in the printed state increases to 2.78,3.09 and 2.06μm,respectively.The formed parts are mainly composed of martensite and retained austenite.Moreover,the NiAl and M23C precipitates form,which are the major strengthening phases of PH13-8Mo stainless steel.The optimal heat treatment process is 925℃×1 h water cooling(WC)+0℃×2 h air cooling(AC)+540℃×4 h AC.Using this heat treatment process,PH13-8Mo formed parts have the optimal comprehensive mechanical properties:the tensile strength,yield strength and impact energy KU2 are 1492 MPa,1432 MPa and 63 J,respectively.The strengthening and toughening via heat treatment are mainly attributed to dislocation strengthening,the formation of NiAl and M23Co precipitates and the change of volume fraction of the retained austenite.

关键词： High-strength stainless steel-Selective laser melting-Heat treatment Microstructure Mechanical property

Dynamic Analysis of A Deepwater Drilling Riser with A New Hang-off System

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第1期38卷 29-41页

作者： LI Yan-wei LIU Xiu-quan WANG Jin-long chen Guo-ming chang Yuan-jiang SHENG Lei-xiang Centre for Offshore Engineering and Safety Technology China University of PetroleumQingdao 266580China National Engineering Laboratory of Offshore Geophysical and Exploration Equipment China University of PetroleumQingdao 266580China China CNOOC Research Institute Co. Ltd.Beijing 100028China

The safety of risers in hang-off states is a vital challenge in offshore oil and gas engineering.A new hang-off system installed on top of risers is proposed for improving the security of risers.This approach leads to a challenging problem:coupling the dynamics of risers with a new hang-off system combined with multiple structures and complex constraints.To accurately analyze the dynamic responses of the coupled system,a coupled dynamic model is established based on the Euler-Bernoulli beam-column theory and penalty function method.A comprehensive analysis method is proposed for coupled dynamic analysis by combining the finite element method and the Newmarkβmethod.An analysis program is also developed in MATLAB for dynamic simulation.The simulation results show that the dynamic performances of the risers at the top part are significantly improved by the new hang-off system,especially the novel design,which includes the centralizer and articulation joint.The bending moment and lateral deformation of the risers at the top part decrease,while the hang-off joint experiences a great bending moment at the bottom of the lateral restraint area which requires particular attention in design and application.The platform navigation speed range under the safety limits of risers expands with the new hang-off system in use.

关键词： deepwater drilling riser new hang-off system dynamic analysis finite element method penalty function method

Development and validation of a nomogram to predict allograft survival after pediatric liver transplantation

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2024年第3期20卷 239-249页

作者： Guang-xiang Gu Shu-Ting Pan Yi-chen Fan chen chen Qiang Xia Department of Liver Surgery Renji HospitalShanghai Jiaotong University School of MedicineNo.160 Pujian RoadPudong New DistrictShanghai 200128China Department of Liver Transplantation Sun Yet-Sen Memorial HospitalSun Yat-Sen UniversityNo.107 Yanjiang West RoadGuangzhou 510080China Clinical Center for Investigation Renji HospitalShanghai Jiaotong University School of MedicineShanghaiChina Department of Anesthesiology Renji HospitalShanghai Jiaotong University School of MedicineShanghaiChina

Background Liver transplantation is the main treatment for cholestatic liver disease and some metabolic liver diseases in children.However,no accurate prediction model to determine the survival probability of grafts prior to surgery exists.This study aimed to develop an effective prognostic model for allograft survival after pediatric liver transplantation.Methods This retrospective cohort study included 2032 patients who underwent pediatric liver transplantation between January 1,2006,and January 1,2020.A nomogram was developed using Cox regression and validated based on bootstrap sampling.Predictive and discriminatory accuracies were determined using the concordance index and visualized using calibration curves;net benefits were calculated for model comparison.An online Shiny application was developed for easy access to the model.Results Multivariable analysis demonstrated that preoperative diagnosis,recipient age,body weight,graft type,preoperative total bilirubin,interleukin-1β,portal venous blood flow direction,spleen thickness,and the presence of heart disease and cholangitis were independent factors for survival,all of which were selected in the nomogram.Calibration of the nomogram indicated that the 1-,3-,and 5-year predicted survival rates agreed with the actual survival rate.The concordance indices for graft survival at 1,3,and 5 years were 0.776,0.757,and 0.753,respectively,which were significantly higher than those of the Pediatric End-Stage Liver Disease and Child-Pugh scoring systems.The allograft dysfunction risk of a recipient could be easily predicted using the following URL:https://aspelt.***.io/ASPELT/l Conclusion The allograft survival after pediatric liver transplantation(ASPELT)score model can effectively predict the graft survival rate after liver transplantation in children,providing a simple and convenient evaluation method for clinicians and patients.

关键词： Allograft survival Nomogram Pediatric liver transplantation

Pyridine-regulated Sb@InSbS3 ultrafine nanoplates as high-capacity and long-cycle anodes for sodium-ion batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第5期43卷 2080-2092页

作者： Jia-Ying Ren xiang-Lin Yu chang-Miao chen Xin-Yu Hu Ting Yang Ming Zhang College of Materials Science and Engineering and College of Science Central South University of Forestry and Technology College of Semiconductors (College of Integrated Circuits) Changsha Semiconductor Technology and Application Innovation Research InstituteHunan University

Sb-based materials exhibit considerable potential for sodium-ion storage owing to their high theoretica capacities.However,the bulk properties of Sb-based materials always result in poor cycling and rate performances.To overcome these issues,pyridine-regulated Sb@InSbS3ultrafine nanoplates loaded on reduced graphene oxides （Sb@InSbS3@rGO） were designed and synthesized.During the synthesis process,pyridine was initially adopted to coordinate with In3+,and uniformly dispersed In2S3ultrafine nanoplates on reduced graphene oxide were generated after sulfidation.Next,partial In3+was exchanged with Sb3+,and Sb@InSbS3@rGO was obtained by using the subsequent annealing method.The unique structure of Sb@InSbS3@rGO effectively shortened the transfer path of sodium ions and electrons and provided a high pseudocapacitance.As the anode in sodium-ion batteries,the Sb@InSbS3@rGO electrode demonstrated a significantly higher reversible capacity better stability (445 m Ah·g-1at 0.1 A·g-1after 200 cycles and 212 mAh·g-1at 2 A·g-1after 1200 cycles),and superior rate (210 mAh·g-1at 6.4 A·g-1) than the electrode without pyridine (355 mAh·g-1at 0.1 A·g-1after 55 cycles and 109 mAh·g-1at 2 A·g-1after 770 cycles)Furthermore,full cells were assembled by using the Sb@InSbS3@rGO as anode and Na3V2（PO4）3as cathode which demonstrated good cycling and rate performances and exhibited promising application prospects.These results indicate that adjusting the microstructure of electrode materials through coordination balance is A·good strategy for obtaining high-capacity,high-rate,and longcycle sodium storage performances.

关键词： Sodium-ion battery Sb-based anode material Pyridine coordination Reduced size nanostructure Half/full cell

Microstructure and mechanical properties of a cast TRIP-assisted multiphase stainless steel

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

China Foundry 2024年第3期21卷 221-228页

作者： Meng-xin Wang Zi-xiang Wu Jing-yu He xiang chen School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

Stainless steels are used in a wide range of complex environments due to their excellent corrosion resistance.Multiphase stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different microstructures.The microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room temperature.Results show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of austenite.The austenite with a lower Ni content undergoes a martensitic transformation during plastic deformation.The tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging treatment.This enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.

关键词： multiphase stainless steel mechanical properties TRIP effect reversed austenite G-phase

Research Progress on the Association between Schizophrenia and Toxoplasma gondii Infection

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2024年第6期37卷 647-660页

作者： Yiting Zhu Xiaohui Yang Miaoru chen Yu Hu Yunfeng chang xiang Wu Department of Forensic Medicine Science Xiangya School of Basic MedicineCentral South UniversityChangsha 410013HunanChina Nursing Department The Third Xiangya Hospital of Central South UniversityChangsha 410013HunanChina Department of Basic Medicine Science Xiangya School of Basic MedicineCentral South UniversityChangsha 410013HunanChina Department of Parasitology Xiangya School of Basic MedicineCentral South UniversityChangsha 410013HunanChina

Toxoplasma gondii(T.gondii or Tg),is an obligatory intracellular parasite with humans as its intermediate hosts.In recent years,significant correlations between T.gondii infection and schizophrenia have been reported,including the possible mediating mechanisms.Currently,mechanisms and hypotheses focus on central neurotransmitters,immunity,neuroinflammation,and epigenetics;however,the exact underlying mechanisms remain unclear.In this article,we review the studies related to T.gondii infection and schizophrenia,particularly the latest research progress.Research on dopamine(DA)and other neurotransmitters,the blood-brain barrier,inflammatory factors,disease heterogeneity,and other confounders is also discussed.In addition,we also summarized the results of some new epidemiological investigations.

关键词： Toxoplasma gondii Schizophrenia Neurotransmitters Neuroinflammation Immunity Epigenetics

Atomically Dispersed Ruthenium Catalysts with Open Hollow Structure for Lithium-Oxygen Batteries

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第2期16卷 154-164页

作者： Xin chen Yu Zhang chang chen Huinan Li Yuran Lin Ke Yu Caiyun Nan chen chen Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Solid State ChemistryUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084People’s Republic of China Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875People’s Republic of China

Lithium–oxygen battery with ultrahigh theoretical energy density is considered a highly competitive next-generation energy storage device,but its practical application is severely hindered by issues such as difficult decomposition of discharge products at present.Here,we have developed N-doped carbon anchored atomically dispersed Ru sites cathode catalyst with open hollow structure(h-RuNC)for Lithium–oxygen battery.On one hand,the abundance of atomically dispersed Ru sites can effectively catalyze the formation and decomposition of discharge products,thereby greatly enhancing the redox kinetics.On the other hand,the open hollow structure not only enhances the mass activity of atomically dispersed Ru sites but also improves the diffusion efficiency of catalytic molecules.Therefore,the excellent activity from atomically dispersed Ru sites and the enhanced diffusion from open hollow structure respectively improve the redox kinetics and cycling stability,ultimately achieving a high-performance lithium–oxygen battery.

关键词： Atomically dispersed Open hollow structure Discharge product Lithium Oxygen battery

Reduction of unactivated alkyl chlorides enabled by light-induced single electron transfer

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第2期67卷 471-481页

作者： Lei Dai Zhao-Fei Zhang xiang-Yu chen School of Chemical Sciences University of the Chinese Academy of SciencesBeijing100049China Institute of Chemistry Chinese Academy of SciencesBeijing100190China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou256606China

Alkyl chlorides are abundant and easily accessible starting materials.However,due to the high reduction potentials associated with unactivated alkyl chlorides,achieving their single electron reduction remains a persistent challenge.This challenge has spurred the exploration of efficient activation methods to overcome this issue.In recent years,photocatalysis has emerged as a mild and potent tool for the single electron reduction of unactivated alkyl chlorides,opening up new possibilities in this field.Considering the rapid advancements in this area,a comprehensive review that provides a conceptual understanding of this emerging field,with a specific focus on reaction design and catalytic mechanisms,would be timely and highly valuable.Hence,we present an overview of various synthetic techniques for photoinduced single electron reduction of unactivated alkyl chlorides.Furthermore,we also discuss the limitations of the present methods and future directions that lie ahead in this field.

关键词： photocatalysis unactivated alkyl chlorides single electron transfer radical reactions

Precipitating thermally reinforcement phase in aluminum alloys for enhanced strength at 400℃

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2024年第5期172卷 71-82页

作者： xiang Su Yuan Lei Yang chen Hongjie Qu Zhixiang Qi Gong Zheng Xu Liu Henggao xiang Guang chen National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China School of Aviation and Mechanical Engineering Changzhou Institute of TechnologyChangzhou 213032China

Heat-resistant aluminum alloys are widely used in aerospace and automotive fields for manufacturing hot components due to their advantages in lightweight design and energy conservation.However,the high-temperature strength of existing cast aluminum alloys is always limited to about 100 MPa at 350℃due to coarsening and transformation of strengthening phases.Here,we reveal that the yield strength and ultimate tensile strength of the T6 state Al-8.4Cu-2.3Ce-1.0Mn-0.5Ni-0.2Zr alloy at 400◦C increase by 34%and 44%after re-aging at 300℃for 100 h,and its thermal strength exhibits distinguished ad-vantage over traditional heat-resistant aluminum alloys.The enhanced elevated-temperature strength is attributed to the reprecipitation of the Ni-bearing T-Al_(20)Cu_(2)Mn_(3)phase,whose number density increases over one time.The significant segregation of Ni,Ce,and Zr elements at the interfaces helps improve the thermal stability of the T phase.The thermostable T phase effectively strengthens the matrix by in-hibiting dislocation motion.Meanwhile,a highly interconnected 3D intermetallic network along the grain boundaries can still remain after long-term re-aging at 300℃,which is conducive to imposing a drag on the grain boundaries at high temperatures.This finding offers a viable route for enhancing the elevated-temperature strength of heat-resistant aluminum alloys,which could provide expanded opportunities for higher-temperature applications.

关键词： Aluminum alloys Precipitation Thermally reinforcement phase Re-aging treatment High-temperature strength