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Gradient microstructure and superior strength-ductility synergy of AZ61 magnesium alloy bars processed by radial forging with different deformation temperatures

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Journal of Materials Science & Technology 2024年第3期170卷 65-77页

作者： Jingfeng Zou Lifeng Ma Yanchun zhu Ling Qin yuan yuan School of Mechanical Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China Heavy Machinery Engineering Research Center of the Ministry Education Taiyuan University of Science and TechnologyTaiyuan 030024China Department of Engineering University of HullCottingham RdHull HU67RXUK National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China

Gradient microstructure modification is a cost-efficient strategy for high strength without compromising ductility,which is urgently needed in the fundamental science of engineering *** this study,heterogeneous structures of AZ61 alloy bars with anisotropic gradients(with different grain size distributions from the surface to the center)were observed to exhibit strong strength-ductility synergies under different deformation tem *** results reveal that the grain refinement process under mediumlow temperature deformation conditions(≤350℃)consists of four transition stages along the radial direction,i.e.,twin activations and deformation band formations,dislocation cells and pile-ups,ultrafine sub-grains,and randomly orientated quasi-micron *** deformation temperatures have a great influence on twin activations and deformation band formations,and the high temperature can easily provoke the initiation of non-basal *** deformation bands were determined as a primary nucleation site due to their highly unstable dislocation hindrance *** in combination with the Radial forging(RF)deformation process,the differences of dynamic precipitates can be attributed to microstructural difference and solubility limit of Al at different tem *** summarizing the tensile test results,the sample forged at 350℃exhibited the best strength-ductility synergy,exhibiting the highest elongation(EL)of 23.2%with a 251 MPa yield strength(YS)and 394 MPa ultimate tensile strength(UTS)in center region,and combined with the highest strength value of 256 MPa YS and 420 MPa UTS in the center region,while the EL was slightly degraded to 19.8%.

关键词： Gradient microstructure Radial forging Strength-ductility synergy Magnesium alloy Strengthening mechanism

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Thermal comfort in a building with Trombe wall integrated with phase change materials in hot summer and cold winter region without air conditioning

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Energy and Built Environment 2024年第1期5卷 58-69页

作者： Jie Li yuan zhang Ziyang zhu Jiangtian zhu Jing Luo Fen Peng Xiaoqin Sun School of Energy and Power Engineering Changsha University of Science and TechnologyChangshaHunan 410114PR China

Trombe wall and phase change materials(PCMs)are two effective ways to regulate indoor thermal ***,Trombe wall surfers from overheating in summer and PCMs suffer from low heat transfer rate caused by the limited thermal *** compensate the shortcomings of the two methods,this paper proposed a Trombe wall system integrated with *** on a light-weight building envelope in Changsha,China,the thermal comfort of 10 kinds of Trombe wall systems with PCMs with a melting temperature of 18-28℃ were *** the integrated indoor discomfort duration(I_(D)),integrated indoor discomfort degree-hour(I_(DH)),indoor air temperature(T_(in)),PCM liquid fraction(γ)and heat flux across wall(q)as evaluation indexes,the indoor thermal comfort was assessed in hot summer and cold winter *** show that the Trombe wall helped PCMs complete the phase change process *** wall with PCM25 next to the wall inner surface possessed the lowest annual I_(D) and I_(DH),as 2877 h and 12,974℃·h,*** with the values in a traditional building,the I_(D) and I_(DH) were reduced by 7.01% and 14.14%.In order to give full play to the heat storage and heat release of the Trombe wall with PCMs,PCMs with phase change temperature 7℃ lower than the peak ambient temperature in summer or 8℃ higher than the winter night temperature was recommended according to regional climate conditions.

关键词： Trombe wall Phase change materials Integrated indoor discomfort duration Integrated discomfort degree-hour Liquid fraction

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Further study on the genesis of lamellar calcite veins in lacustrine black shale--A case study of Paleogene in Dongying Depression, China

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Petroleum Science 2024年第3期21卷 1508-1523页

作者： Guan-Min Wang Yun-Jiao zhang Zi-yuan Yin Rui zhu Zhi-Yao Hou Yu Bai School of Geosciences China University of Petroleum(East China)Qingdao266580ShandongChina

Lamellar calcite veins are prevalent in carbonate-rich,lacustrine dark *** formation mechanisms of these veins have been extensively debated,focusing on factors such as timing,depth,material source,and driving *** paper examines dark lacustrine shale lamellar calcite veins in the Paleogene strata of Dongying Depression,using various analytical techniques:petrography,isotope geochemistry,cathodoluminescence,inclusion thermometry,and electron probe *** distinct types of calcite veins have been identified:granular calcite veins and sparry calcite *** two types differ significantly in color,grain structure,morphology,and *** further investigation,it was observed that vein generation occurred from the shallow burial period to the maturation of organic matter,with a transition from granular calcite veins to sparry calcite *** granular calcite veins exhibit characteristics associated with the shallow burial period,including plastically deformed laminae and veins,the development of strawberry pyrite,the absence of oil and gas,weak fractionation in oxygen isotopes,and their contact relationship with sparry calcite *** granular calcite veins were likely influenced by the reduction of sulfate *** the other hand,sparry calcite veins with fibrous grains are antitaxial and closely linked to the evolution and maturation of organic *** contain oil and gas inclusions and show a distribution range of homogenization temperature between 90℃ and 120℃ and strong fractionation in oxygen isotopes,indicating formation during the hydrocarbon expulsion *** carbon isotope analysis of the surrounding rocks and veins suggests that the material for vein formation originates from the shale itself,specifically authigenic micritic calcite modified by the action of *** opening of horizontal fractures and vein formation is likely driven by fluid overpressure resulting from undercompaction and hydrocarb

关键词： Calcite veins Shale diagenesis Material source Formation period Formation mechanism

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Higher ambient temperatures may worsen obstructive sleep apnea:A nationwide smartwatch-based analysis of 6.2 million person-days

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Science Bulletin 2024年第13期69卷 2114-2121页

作者： Anni Li Qingli zhang yuan Yao Xinlei zhu Cong Liu Yutao Guo Haidong Kan Renjie Chen School of Public Health Key Lab of Public Health Safety of the Ministry of Education and NHC Key Lab of Health Technology AssessmentFudan UniversityShanghai 200032China Ministry of Education-Shanghai Key Laboratory of Children’s Environmental Health Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200092China Department of Pulmonary Vessel and Thrombotic Disease Sixth Medical CenterChinese PLA General HospitalBeijing 100048China Institute for Hospital Management Research Chinese PLA General HospitalBeijing 100048China Children’s Hospital of Fudan University National Children’s Medical CenterShanghai 201102China School of Public Health Hengyang Medical SchoolUniversity of South ChinaHengyang 421001China

Obstructive sleep apnea(OSA)is a serious type of sleep disorder that can lead to cardiometabolic and neurocognitive *** utilized smart device-based photoplethysmography technology to collect sleep data from the Chinese population from 2019 to *** lag nonlinear models combined with a generalized nonlinear model or a linear mixed effects model were used to investigate the shortterm associations between daily temperature and indicators of OSA *** included a total of 6,232,056 d of sleep monitoring data from 51,842 participants with moderate to severe risk of OSA from 313 Chinese *** relationships between ambient temperature and OSA exacerbation,apneahypopnea index(AHI),and minimum oxygen saturation(MinSpO_(2))were almost linear and present only on the same *** temperatures were associated with a greater risk of OSA exacerbation,with an 8.4%(95%confidence interval(CI):7.6%–9.3%)increase per 10℃increase in temperature.A 10℃increase in daily temperature corresponded to an AHI increase of 0.70 events/h(95%CI:0.65–0.76)and a MinSpO_(2)decrease of 0.18%(95%CI:0.16%–0.19%).Exposure to elevated temperatures during the night can also lead to adverse *** effects of higher temperatures on OSA severity were stronger among men,participants with a body mass index24 kg/m2,those aged 45 years and older,individuals with a history of hypertension and diabetes,and during the cold *** large-scale,nationwide,longitudinal study provides robust evidence suggesting that higher ambient temperatures may immediately worsen OSA.

关键词： Obstructive sleep apnea Temperature Apnea-hypopnea index Oxygen saturation Smart device

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Oxygen reduction electrocatalysis:From conventional to single-atomic platinum-based catalysts for proton exchange membrane fuel cells

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Frontiers in Energy 2024年第2期18卷 206-222页

作者： Cheng yuan Shiming zhang Jiujun zhang Institute for Sustainable Energy/College of Sciences Shanghai UniversityShanghai 200444China

Platinum(Pt)-based materials are still the most efficient and practical catalysts to drive the sluggish kinetics of cathodic oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).However,their catalysis and stability performance still need to be further improved in terms of corrosion of both carbon support and Pt catalyst particles as well as Pt loading *** on the developed synthetic strategies of alloying/nanostructuring Pt particles and modifying/innovating supports in developing conventional Pt-based catalysts,Pt single-atom catalysts(Pt SACs)as the recently burgeoning hot materials with a potential to achieve the maximum utilization of Pt are comprehensively reviewed in this *** design thoughts and synthesis of various isolated,alloyed,and nanoparticlecontained Pt SACs are *** single-atomic Pt coordinating with non-metals and alloying with metals as well as the metal-support interactions of Pt single-atoms with carbon/non-carbon supports are emphasized in terms of the ORR activity and stability of the *** advance further research and development of Pt SACs for viable implementation in PEMFCs,various technical challenges and several potential research directions are outlined.

关键词： oxygen reduction electrocatalysis Pt singleatom catalysts conventional Pt-based catalysts design thoughts and synthesis metal-support interactions

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Novel wreck salvaging method using curved rectangular pipe basing method:A case study of"Yangtze River EstuaryⅡ"ancient shipwreck salvage project

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Underground Space 2024年第5期18卷 97-113页

作者： Qianwei zhuang Guofang Gong Dongrong Zhou Chi zhang Xin Huang Xiaodong zhu Weihao yuan Deng Li School of Mechanical Engineering Zhejiang UniversityHangzhou 310030China Shanghai Tunnel Engineering Co.Ltd. Shanghai 200137China Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China College of Civil Engineering and Architecture Xinjiang UniversityUrumqi 830047China Shanghai Salvage Company Shanghai 200090China

Shipwreck salvage is a risky,time-consuming,and expensive *** there are many sunken ships along coastlines and in the open seas,the salvage process of a sunken ship has rarely been *** integrated salvage of the"Yangtze River EstuaryⅡ"shipwreck used a novel method with 22 closely locked curved rectangular pipes to form a watertight base that wrapped the shipwreck *** basing was lifted out of the water using a powerful crane situated on an engineering *** the first time,the tunneling method was used in a shipwreck salvage project,significantly reducing the disturbance to the shipwreck and its stowage,thereby preserving the original state and integrity of the shipwreck to the greatest *** this study,the basic concepts of the salvage method and process are *** to critical issues in the new salvage method are provided,including jacking force prediction and major considerations for the structural design of the salvage *** design of the salvage system and salvage process of the"Yangtze River EstuaryⅡ"shipwreck are *** monitored jacking force,pipe deformation,and observed water-tightness verified that the proposed method was effective and *** possible application scenarios for the proposed method are presented at the end.

关键词： Pipe jacking Shipwreck salvage Yangtze River EstuaryⅡ Structural design

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Finite-Time Stabilization for Constrained Discrete-time Systems by Using Model Predictive Control

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1656-1666页

作者： Bing zhu Xiaozhuoer yuan Li Dai Zhiwen Qiang IEEE the Seventh Research Division Beihang UniversityBeijing 100191China the School of Automation Beijing Institute of TechnologyBeijing 100081China

In this paper, a model predictive control(MPC)framework is proposed for finite-time stabilization of linear and nonlinear discrete-time systems subject to state and control constraints. The proposed MPC framework guarantees the finite-time convergence property by assigning the control horizon equal to the dimension of the overall system, and only penalizing the terminal cost in the optimization, where the stage costs are not penalized explicitly. A terminal inequality constraint is added to guarantee the feasibility and stability of the closed-loop *** feasibility can be improved via augmentation. The finite-time convergence of the proposed MPC is proved theoretically,and is supported by simulation examples.

关键词： Constraints deadbeat control finite-time stabilization model predictive control(MPC)

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Micro-flow structure at regime transition from bubbling to turbulent fluidization in a fluidized bed

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Particuology 2024年第6期89卷 117-130页

作者： Chaoyu Yan Yue yuan Xiaoyang Wei Jesse zhu State Key Laboratory of Heavy Oil Processing Beijing Key Laboratory of Process Fluid Filtration and SeparationCollege of Mechanical and Transportation EngineeringChina University of PetroleumBeijing 102249China China Beacons Institute The University of NottinghamNingbo315100China Department of Chemical and Biochemical Engineering University of Western OntarioLondonOntarioN6A 5B9Canada

Gas-solid fluidized beds have found extensive utilization in frontline manufacturing,in particular as low-velocity *** fluidization status,the bubbling or turbulent flow regime and the transition in between,determine the system performance in practical *** the convoluted hydrodynamics are quantitively evaluated through numerous data-processing methodologies,none of them alone can reflect all the critical information to identify the transition from the bubbling to the turbulent ***,this study was to exploit a coupling data processing methodology,in the combination of standard deviation,power spectrum density,probability density function,wavelet transform,and wavelet multiresolution method,to jointly explain the micro-flow structure at the regime transition from bubbling to turbulent *** transient differential pressure fluctuation was measured for the evaluation in a fluidized bed(0.267 m i.d.×2.5 m height)with FCC catalysts(d_(p)=65μm,ρ_(p)=1780kg/m^(3))at different superficial gas velocities(0.02–1.4 m/s).The results show that the onset of turbulent fluidization starts earlier in the top section of the bed than in the bottom *** wavelet decomposition displays that the fluctuation of differential pressure mainly concentrates on the sub-signals with an intermediate frequency *** sub-signals could be synthesized into three types of scales(micro-scale,meso-scale,and macro-scale),representing the multi-scale hydrodynamics in the fluidized *** micro-scale signal has the characteristic information of bubbling fluidization,and the characteristic information of turbulent fluidization is mainly represented by the meso-scale *** work provides a systematic comprehension of fluidization status assessment and serves as an impetus for more coupling analysis in this sector.

关键词： Flow regime transition Bubbling fluidization Turbulent fluidization Micro-flow structure Differential pressure fluctuation

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Insights and implications of sexual dimorphism in osteoporosis

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Bone Research 2024年第1期12卷 20-49页

作者： yuan-yuan zhang Na Xie Xiao-Dong Sun Edouard C.Nice Yih-Cherng Liou Canhua Huang Huili zhu Zhisen Shen Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province Sichuan Research Center for Drug Precision Industrial TechnologyWest China School of PharmacySichuan UniversityChengdu 610041China West China School of Basic Medical Sciences&Forensic Medicine Sichuan UniversityChengdu 610041China Department of Biochemistry and Molecular Biology Monash UniversityClaytonVIC 3800Australia Department of Biological Sciences Faculty of ScienceNational University of SingaporeSingapore 117543Republic of Singapore Department of Biotherapy Cancer Center and State Key Laboratory of BiotherapyWest China Hospitaland West China School of Basic Medical Sciences&Forensic MedicineSichuan UniversityChengdu 610041China Key Laboratory of Birth Defects and Related Diseases of Women and Children of Ministry of Education Department of Reproductive MedicineWest China Second University Hospital of Sichuan UniversityChengduChina Department of Otorhinolaryngology and Head and Neck Surgery The Affiliated Lihuili HospitalNingbo University315040 NingboZhejiangChina

Osteoporosis,a metabolic bone disease characterized by low bone mineral density and deterioration of bone microarchitecture,has led to a high risk of fatal osteoporotic fractures *** evidence has revealed that sexual dimorphism is a notable feature of osteoporosis,with sex-specific differences in epidemiology and ***,females are more susceptible than males to osteoporosis,while males are more prone to disability or death from the *** date,sex chromosome abnormalities and steroid hormones have been proven to contribute greatly to sexual dimorphism in osteoporosis by regulating the functions of bone *** the sex-specific differences in osteoporosis and its related complications is essential for improving treatment strategies tailored to women and *** literature review focuses on the mechanisms underlying sexual dimorphism in osteoporosis,mainly in a population of aging patients,chronic glucocorticoid administration,and ***,we highlight the implications of sexual dimorphism for developing therapeutics and preventive strategies and screening approaches tailored to women and ***,the challenges in translating bench research to bedside treatments and future directions to overcome these obstacles will be discussed.

关键词： osteoporosis epidemiology overcome

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Relationships between blood chromium exposure and liver injury:Exploring the mediating role of systemic inflammation in a chromate-exposed population

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Journal of Environmental Sciences 2024年第9期143卷 224-234页

作者： Zekang Su Yali zhang Shiyi Hong Qiaojian zhang Jiayu Xu Guiping Hu Xiaojun zhu Fang yuan Shanfa Yu Tianchen Wang Guang Jia Department of Occupational and Environmental Health Sciences School of Public HealthPeking UniversityBeijing 100191China School of Engineering Medicine and Beijing Advanced Innovation Center for Big Data-Based Precision Medicine Beihang UniversityBeijing 100191China National Center for Occupational Safety and Health Beijing 102308China Department of Occupational Health and Radiological Health Chongqing Centers for Disease Control and PreventionChongqing 400042China Henan Institute for Occupational Medicine Zhengzhou 450052China Department of Clinical Laboratory Third Hospital of Peking UniversityBeijing 100191China

Hexavalent chromium and its compounds are prevalent pollutants,especially in the work environment,pose a significant risk for multisystem toxicity and *** it is known that chromium accumulation in the liver can cause damage,the dose-response relationship between blood chromium(Cr)and liver injury,as well as the possible potential toxic mechanisms involved,remains poorly *** address this,we conducted a follow-up study of 590 visits from 305 participants to investigate the associations of blood Cr with biomarkers for liver injury,including serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL),and direct bilirubin(DBIL),and to evaluate the mediating effects of systemic ***(PLT)and the platelet-to-lymphocyte ratio(PLR)were utilized as biomarkers of systemic *** the linear mixed-effects analyses,each 1-unit increase in blood Cr level was associated with estimated effect percentage increases of 0.82%(0.11%,1.53%)in TBIL,1.67%(0.06%,3.28%)in DBIL,0.73%(0.04%,1.43%)in ALT and 2.08%(0.29%,3.87%)in AST,***,PLT mediated 10.04%,11.35%,and 10.77%increases in TBIL,DBIL,and ALT levels induced by chromate,*** addition,PLR mediated 8.26%and 15.58%of the association between blood Cr and TBIL or *** findings shed light on the mechanisms underlying blood Cr-induced liver injury,which is partly due to worsening systemic inflammation.

关键词： Blood chromate Liver injury Systemic inflammation Mediation analysis

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