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

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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 *** stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different *** 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 *** 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 with a lower Ni content undergoes a martensitic transformation during plastic *** 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 *** 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

Combined effects of massive reclamation and dredging on the variations in hydrodynamic and sediment transport in Lingdingyang Estuary,China

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Frontiers of Earth Science 2024年第1期18卷 127-147页

作者： Kanglin chen Yitong LIN jing LIU Zixiao he Liangwen JIA School of Geography and Remote Sensing Guangzhou UniversityGuangzhou 510006China School of Marine Science Sun Yat-Sen UniversityGuangzhou 510275China School of Marine Engineering and Technology Sun Yat-Sen UniversityGuangzhou 510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519080China Guangdong Province Engineering Research Center of Coasts Islands and ReefsGuangzhou 510275China

Anthropogenic disturbances associated with the rapid development of coastal cities have drastically influenced the hydrodynamics and sediment transport processes in many large estuaries *** Estuary(LE),located in the central and southern part of the Pearl River Delta,southern China with a long history of high-intensity anthropogenic disturbances,was studied to explore the contribution rate and mechanism underlying the alteration in hydrodynamics and sediment transport under each phase of human activity.A state-of-the-art modeling tool(TELEMAC-2D),was used to study the variations in the hydrodynamics and sediment transport,accounting for reclamation-induced shoreline and dredging-induced topography *** results indicated that:i)under the influence of successive land reclamation,the general distribution of the Confluence Hydrodynamic Zone(CHZ)in LE varied from scattered to concentrated,and these zones moved 3–5 km ***)Large-scale channel dredging weakened the residual flow in LE,decreasing the residual flow in the Inner-Lingding Estuary(ILE)by 62.45%.This was initiated by the enhancement of tidal dynamics through changes in the bottom friction caused by dredging in the *** contrast,massive reclamation decreased the residual flow in the ILE by 17.55%and increased that in the Outer-Lingding Estuary(OLE).iii)Despite disturbances related to land reclamation and dredging,the estuarine jet flow in LE remained a turbulent jet system,and the estuarine jet flow became more *** addition,the position of the estuarine jet source moved 6–13 km ***)Both reclamation and dredging decreased the SSC in the ILE and increased the SSC in the *** weakened the SSC in the ILE by 62.19%,whereas dredging enhanced the SSC in the OLE by 49%.Spatially,reclamation resulted in an increase in the SSC near the outlets and a decrease in the SSC in the northern portion of the Western *** mainly increased the SSC in the north

关键词： reclamation and dredging estuarine jet flow dynamics and sediment transport mechanism Lingdingyang Estuary

MADRL-based UAV swarm non-cooperative game under incomplete information

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Chinese Journal of Aeronautics 2024年第6期37卷 293-306页

作者： Ershen WANG Fan LIU chen HONG jing GUO Lin ZHAO Jian XUE Ning he School of Electronic and Information Engineering Shenyang Aerospace UniversityShenyang 110136China College of Robotics Beijing Union UniversityBeijing 100101China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China College of Smart City Beijing Union UniversityBeijing 100101China

Unmanned Aerial Vehicles(UAVs)play increasing important role in modern *** this paper,considering the incomplete observation information of individual UAV in complex combat environment,we put forward an UAV swarm non-cooperative game model based on Multi-Agent Deep Reinforcement Learning(MADRL),where the state space and action space are constructed to adapt the real features of UAV swarm air-to-air *** multi-agent particle environment is employed to generate an UAV combat scene with continuous observation *** recently popular MADRL methods are compared extensively in the UAV swarm noncooperative game model,the results indicate that the performance of Multi-Agent Soft Actor-Critic(MASAC)is better than that of other MADRL methods by a large *** swarm employing MASAC can learn more effective policies,and obtain much higher hit rate and win *** under different swarm sizes and UAV physical parameters are also performed,which implies that MASAC owns a well generalization ***,the practicability and convergence of MASAC are addressed by investigating the loss value of Q-value networks with respect to individual UAV,the results demonstrate that MASAC is of good practicability and the Nash equilibrium of the UAV swarm non-cooperative game under incomplete information can be reached.

关键词： UAV swarm Reinforcement learning Deep learning Multi-agent Non-cooperative game Nash equilibrium

Validation and performance of three scoring systems for predicting primary non-function and early allograft failure after liver transplantation

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hepatobiliary & Pancreatic Diseases International 2024年第5期23卷 463-471页

作者： Yu Nie Jin-Bo Huang Shu-Jiao he Hua-Di chen Jun-Jun Jia jing-jing Li Xiao-Shun he Qiang Zhao General Surgery Center Department of Hepatobiliary Surgery IIResearch Center for Artificial Organ and Tissue EngineeringGuangzhou Clinical Research and Transformation Center for Artificial LiverInstitute of Regenerative MedicineZhujiang HospitalSouthern Medical UniversityGuangzhou 510515China Organ Transplant Center the First Affiliated HospitalSun Yat-sen UniversityGuangzhou 510080China Guangdong Provincial Key Laboratory of Organ Donation and Transplant Immunology Guangzhou 510080China Guangdong Provincial International Cooperation Base of Science and Technology Guangzhou 510080China Division of hepatobiliary Pancreatic Surgery the First Affiliated HospitalZhejiang University School of MedicineHangzhou 310003China

Background: Primary non-function(PNF) and early allograft failure(EAF) after liver transplantation(LT) seriously affect patient outcomes. In clinical practice, effective prognostic tools for early identifying recipients at high risk of PNF and EAF were urgently needed. Recently, the Model for Early Allograft Function(MEAF), PNF score by King's College(King-PNF) and Balance-and-Risk-Lactate(BAR-Lac) score were developed to assess the risks of PNF and EAF. This study aimed to externally validate and compare the prognostic performance of these three scores for predicting PNF and EAF. Methods: A retrospective study included 720 patients with primary LT between January 2015 and December 2020. MEAF, King-PNF and BAR-Lac scores were compared using receiver operating characteristic(ROC) and the net reclassification improvement(NRI) and integrated discrimination improvement(IDI) analyses. Results: Of all 720 patients, 28(3.9%) developed PNF and 67(9.3%) developed EAF in 3 months. The overall early allograft dysfunction(EAD) rate was 39.0%. The 3-month patient mortality was 8.6% while 1-year graft-failure-free survival was 89.2%. The median MEAF, King-PNF and BAR-Lac scores were 5.0(3.5–6.3),-2.1(-2.6 to-1.2), and 5.0(2.0–11.0), respectively. For predicting PNF, MEAF and King-PNF scores had excellent area under curves(AUCs) of 0.872 and 0.891, superior to BAR-Lac(AUC = 0.830). The NRI and IDI analyses confirmed that King-PNF score had the best performance in predicting PNF while MEAF served as a better predictor of EAD. The EAF risk curve and 1-year graft-failure-free survival curve showed that King-PNF was superior to MEAF and BAR-Lac scores for stratifying the risk of EAF. Conclusions: MEAF, King-PNF and BAR-Lac were validated as practical and effective risk assessment tools of PNF. King-PNF score outperformed MEAF and BAR-Lac in predicting PNF and EAF within 6 months. BAR-Lac score had a huge advantage in the prediction for PNF without post-transplant variables. Proper use

关键词： Primary non-function Early allograft failure Risk predicting model Liver transplantation

Free-standingβ-Ta_(2)O_(5)/SWCNTs composite film for high-rate Li-ion storage

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Science China(Technological Sciences) 2024年第2期67卷 616-626页

作者： WU ZhiMin LIU JiaJia he XingYu BIAN jing ZHU XianJun chen JianMei LI JianMin College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology) Nanjing Universityof Posts and TelecommunicationsNanjing 210023China Department of Pathology College of Medicine University of CincinnatiCincinnatiOH 45267USA

The rapid development of portable and wearable electronic devices is responding to the urgent demand for high-efficiency flexible energy storage *** supercapacitors,showing long cycle life,high power density,and good safety,are considered ideal ***,the relatively low energy density restricts their practical *** a large dielectric constant of 18-46,Ta_(2)O_(5)-based materials typically exhibit excellent electron-binding ability,which is critical for enhancing the energy density of *** this work,the free-standingβ-Ta_(2)O_(5)/single-walled carbon nanotubes(SWCNTs)composite film was prepared,with a highβ-Ta_(2)O_(5)loading of over 70%.By anchoringβ-Ta_(2)O_(5)nanoparticles onto the surface of SWCNTs,the system’s flexibility and conductivity were significantly enhanced,which also facilitated the intercalation electrodynamics of metal *** a result,the flexibleβ-Ta_(2)O_(5)/SWCNTs film exhibits excellent Li-ion storage performance,with a high volumetric specific capacitance of 392.3 F cm^(-3)at the scan rate of 10 mV s^(-1)and 198.9 F cm^(-3)at 500 mV s^(-1).In addition,the asymmetric device,assembled by theβ-Ta_(2)O_(5)/SWCNTs and activated carbon films,shows a high energy density of 45.5 Wh kg^(-1)at the power density of 10.8 kW kg^(-1).This technique opens up a new avenue for improving the energy density and rate performance of flexible supercapacitors.

关键词： pseudocapacitor Li-ion storage β-Ta_(2)O_(5)/SWCNTs film flexible device high-rate capability

Highly dispersed MgInCe-mixed metal oxides catalyzed direct carbonylation of glycerol and CO_(2)into glycerol carbonate

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Chinese Journal of Chemical Engineering 2024年第8期72卷 153-163页

作者： Xufang chen Xin Shu Yanru Zhu Jian Zhang Zhigang Chai Hongyan Song Zhe An jing he State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China Quzhou Institute for Innovation in Resource Chemical Engineering Quzhou 324000China

Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so *** direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol *** investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.

关键词： Catalytic reaction engineering Glycerol carbonate Direct carbonylation from glycerol Carbon dioxide Mixed metal oxides Synergistic catalysis

MALDI coupled with laser-postionization and trapped ion mobility spectrometry contribute to the enhanced detection of lipids in cancer cell spheroids

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Chinese Chemical Letters 2024年第4期35卷 464-468页

作者： jing chen Peisi Xie Pengfei Wu Yu he Zian Lin Zongwei Cai Ministry of Education Key Laboratory of Analytical Science for Food Safety and Biology Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food SafetyCollege of ChemistryFuzhou UniversityFuzhou 350116China Department of Chemistry State Key Laboratory of Environmental and Biological AnalysisHong Kong Baptist UniversityHong KongChina College of Forestry Nanjing Forestry UniversityNanjing 210018China

Cancer cell spheroids(CCS) are a valuable three-dimensional cell model in cancer studies because they could replicate numerous characteristics of solid tumors. Increasing researches have used matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI) to investigate the spatial distribution of endogenous compounds(e.g., lipids) in CCS. However, only limited lipid species can be detected owing to a low ion yield by using MALDI. Besides, it is still challenging to fully characterize the structural diversity of lipids due to the existence of isomeric/isobaric species. here, we carried out the initial application of MALDI coupled with laser-postionization(MALDI-2) and trapped ion mobility spectrometry(TIMS) imaging in HCT116 colon CCS to address these challenges. We demonstrated that MALDI-2 is capable of detecting more number and classes of lipids in HCT116 colon CCS with higher signal intensities than MALDI. TIMS could successfully separate numerous isobaric/isomeric species of lipids in CCS. Interestingly, we found that some isomeric/isobaric species have totally different spatial distributions in colon CCS. Further MS/MS imaging analysis was employed to determine the compositions of fatty acid chains for isomeric species by examining disparities in signal intensities and spatial distributions of product ions. This work stresses the robust ability of TIMS and MALDI-2 imaging in analyzing endogenous lipids in CCS, which could potentially become powerful tools for future cancer studies.

关键词： Matrix-assisted laser desorption/ionization(MALDI) Mass spectrometry imaging MALDI coupled with laser-postionization Trapped ion mobility spectrometry Cancer cell spheroids

The effect of Ti and Zr content on the structure,mechanics and energy-release characteristics of Ti—Zr—Ta alloys

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Defence Technology（防务技术） 2024年第1期31卷 343-350页

作者： Jia-yu Meng jing-zhi he Bin Zhang Jin chen Shun Li Dun Niu Yu Tang Xi’an Modern Chemistry Research Institute Xi'an710065China College of Aerospace Science and Engineering National University of Defense TechnologyChangsha410073China

Energetic structural materials(ESMs)are a new type of structural materials with bearing and damage *** this work the microstructure,mechanical properties and energy release characteristics of multi-element Ti-Zr-Ta alloys with good casting performance were *** microstructure of the Ti_(x)ZrTa alloys gradually change from BCC+HCP to single BCC structure with the increase of *** the Ti_(2)Zr_(y)Ta alloys was still uniform and single BCC structure with the increase of *** evolution of microstructure and composition then greatly affect the mechanical properties and energy-release characteristics of Ti-Zr-Ta *** synergistic effect of dual phase structure increases the fracture strain of Ti_(x)ZrTa(x=0.2,0.5)with the Ti content decreases,while the fracture strain of Ti_(x)ZrTa(x=2.0,3.0,4.0)gradually increase with the Ti content increases caused by the annihilation of the obstacles for dislocation *** as Zr content increases,the fracture strain of Ti_(2)Zr_(y)Ta alloys decrease,then the oxidation reaction rate and fragmentation degree gradually *** higher oxidation rate and the lager exposed oxidation area jointly leads the higher releasing energy efficiency of Ti_(x)ZrTa alloys with low Ti content and Ti_(2)Zr_(y)Ta alloys with high Zr content.

关键词： Energetic structural materials Ti-Zr-Ta Multi-element alloy Energy release characteristics

Gravitational wave fluxes on generic orbits in near-extreme Kerr spacetime:Higher spin and large eccentricity

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 16-28页

作者： Changkai chen Jiliang jing Department of Physics Key Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of EducationSynergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China

To accurately obtain the waveform template of gravitational waves, substantial computational resources and extremely high precision are often required. In a previous study, we employed the confluent heun function to obtain an exact solution to the Teukolsky equation. This approach allowed us to efficiently and accurately calculate the gravitational wave flux for a particle in circular orbits around a Schwarzschild black hole. Building on this method, we now extend its application to calculate the asymptotic gravitational wave fluxes from a particle in generic orbits around a near-extreme Kerr black hole. Our extended method proves particularly effective in handling computational challenges associated with large eccentricities(e = 0.9), higher spins(a = 0.999), higher harmonic modes, and strong-field regions. The results we obtained significantly outperform those derived from the numerical integration method based on the Mano-Suzuki-Takasugi method.

关键词： gravitational wave fluxes exact solution Teukolsky equation near-extreme Kerr black hole