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Experiment of Flow Regime Map and Local Condensing Heat Transfer Coefficients Inside Three Dimensional Inner Microfin Tubes

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Journal of Thermal Science 1999年第1期8卷 44-50页

作者： Yang Du (Department of Oil Mechanical Engineering, Logistical Engineering University,Chongqing 400016,China) ming dao xin(Institute of Engineering Thermophysics, Chongqing University, Chongqing 400044, China) Department of Oil Mechanical Engineering Logistical Engineering University Chongqing China Institute of Engineering Thermophysics Chongqing University Chongqing China

This paper developed a new type of three dimensional inner microfin tube. The experimental results of the flow patterns for the horizontal condensation inside these tubes are reported in the paper. The flow patterns for the horizontal condensation inside the new made tubes are divided into annular flow, stratified flow and intermittent flow within the test conditions. The experiments of the local heat transfer coefficients for the different flow patterns have been systematically carried out. The experiments of the local heat transfer coefficients changing with the vapor dryness fraction have also been carried out. As compared with the heat transfer coefficients of the two dimensional inner microfin tubes, those of the three dimensional inner microfin tubes increase 47-127% for the annular flow region, 38-183% for the stratified flow and 15-75% for the intermittent flow, respectively. The enhancement factor of the local heat transfer coefficients is from 1.8-6.9 for the vapor dryness fraction from 0.05 to 1.

关键词： heat transfer coefficients heat transfer enhancement horizontal condensation three dimensional inner microfin tube two-phase flow patterns.

Metal complexes of bipyridine-functionalized covalent organic frameworks as efficient electrocatalysts for oxygen evolution reaction

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Rare Metals 2024年第7期43卷 3096-3106页

作者： Zhuang-Zhuang Wu Tian Xia Ying Liang Yong-Peng Li Zhu-Yin Sui Li-Juan Feng dao-Xiong Wu xin-Long Tian Qi Chen State Key Laboratory of Marine Resource Utilization in South China Sea School of Marine Science and EngineeringHainan UniversityHaikou 570228China School of Chemistry and Chemical Engineering Yantai UniversityZhuhai519041China School of Bioengineering Zhuhai Campus of Zunyi Medical UniversityZhuhai519041China

Electrocatalytic water splitting is considered a clean and practic al method for producing *** this study,COF-Bpy,a bipyridine-functionalized covalent organic framework(COF),was prepared via post-synthetic modification,after which electrocatalysts for the oxygen evolution reactions(OER)were formed through coordination to single-or double-transition metals(Fe,Co,Ni,FeCo,FeNi or CoNi).COF-Bpy@FeNi delivered the best OER performance among the studied electrocatalysts,with an overpotential of 399 mV at 10 mA·cm^(-2)in an alkaline electrolyte(1.0 mol·L^(-1)KOH aqueous).Notably,the electrocatalytic performance of COF-Bpy@FeNi showed slight degradation during durability testing,which is ascribable to its irreversible benzoquinoline structure and strong metal *** expected,COF-Bpy@FeNi exhibited a low overpotential of 347 mV at a turnover frequency(TOF)of 0.1 s^(-1),which suggests that COF-Bpy@FeNi possesses excellent intrinsic electroc atalytic OER ***,density functional theory(DFT)calculations reveal that the Ni site plays a major role,while the Fe site adjusts the electronic structure of the Ni ions,which rationalizes the excellent OER properties of COF-Bpy@*** study not only provides a simple and efficient method for complexing COFs with transition metals,but also offers a novel strategy for designing porous organic polymer electrocatalysts.

关键词： Covalent organic framework Oxygen evolution reactions(OER)electrocatalyst Nickel-iron synergy Water splitting

Mechanical Behavior and Failure Mechanism of an As-Extruded Mg-11wt%Y Alloy at Elevated Temperature

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 969-981页

作者： Lan Zhang dao-Kui Xu Bao-Jie Wang Cui-Lan Lu Shuo Wang Xiang-Bo Xu Dong-Liang Wang xin Lv En-Hou Han School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang110159China Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang110819China Institute of Corrosion Science and Technology Guangdong510070China

Through carrying out the high-temperature tensile experiments on an as-extruded Mg-11wt%Y alloy at 350℃,400℃,450℃,500℃and 550℃,the mechanical behavior and fracture mechanisms at elevated temperatures are investigated and *** results show that with the increase of temperature,the yield strength and ultimate tensile strength of the alloy increase at first and then decrease,while that the elongation ratio decreases firstly and then *** the sample being tested at 350℃,the values of yield strength,ultimate tensile strength and the elongation ratio are 188 MPa,266 MPa and 11%,*** 400℃,the yield strength and ultimate tensile strength reach the maximum values of,respectively,198 MPa and 277 MPa,but the elongation ratio is the lowest and its value is only 8%.When the applied temperature is increased to 550℃,the values of yield strength and ultimate tensile strength,respectively,decrease to 140 MPa and 192 MPa and the elongation ratio increases to 38%.Failure analysis demonstrates that the fracture surfaces of different samples are mainly composed of plastic dimples and exhibit the typical characteristic of ductile *** observation to the fracture side surfaces indicates that at the temperatures of 350℃and 400℃,microcracks mainly initiate in the interior of Mg_(24)Y_(5)*** the temperatures are 450℃,500℃and 550℃,the cracks preferentially initiate at the Mg_(24)Y_(5)/α-Mg interfaces.

关键词： Mg-Y alloy High-temperature tensile properties Fracture mechanism Failure analysis

Normal and Superconducting Properties of La3Ni2O7

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Chinese Physics Letters 2024年第7期41卷 145-156页

作者：王猛闻海虎吴涛姚道新向涛 Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of PhysicsSun Yat-Sen University National Laboratory of Solid State Microstructures and Department of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of China Institute of Physics Chinese Academy of Sciences School of Physics University of Chinese Academy of Sciences

This review provides a comprehensive overview of current research on the structural,electronic,and magnetic characteristics of the recently discovered high-temperature superconductor La3Ni2O7under high *** present the experimental results for synthesizing and characterizing this material,derived from measurements of transport,thermodynamics,and various spectroscopic techniques,and discuss their physical implications.

关键词： Nickel compounds

Innovative coaxial high-temperature thin-film sensor with core-shell structure surpassing traditional multilayer films

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Rare Metals 2024年第8期43卷 3854-3867页

作者： Chao Wu Guo-Chun Chen Fu-xin Zhao Fan Lin Ying-Jun Zeng Yan-Zhang Fu Yan-Song Zhang Li-Da Xu Qin-Nan Chen Rui Tang dao-Heng Sun Zhen-Yin Hai Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China AECC Shenyang Engine Institute Shenyang 110015China School of Aerospace Engineering Xiamen UniversityXiamen 361005China

High-temperature thin-film sensors(TFSs)often suffer from inadequate tolerance to elevated *** this study,an innovative approach is presented to fabricate in situ integrated TFSs with a core-shell structure on alloy components using coaxial multi-ink printing *** method replaces traditional layerby-layer(LbL) deposition and LbL sintering processes and achieves simplified one-step *** coaxial TFS includes a conductive Pt core for conducting and sensing and a dielectric shell for electrical isolation and high-temperature *** coaxial Pt resistance grid demonstrates excellent high-temperature stability,with a resistance drift rate of only 0.08%·h^(-1) at 800 ℃,significantly lower than traditional Pt *** employing this method,a Pt thin-film strain gauge(TFSG) is fabricated that boasts remarkable high-temperature electromechanical *** effectively addresses the problem of sensitivity degradation experienced by traditional LbL Pt TFSGs when subjected to high *** demonstrate the system integration potential of the technique by printing and verifying the functionality of a long-path thinfilm resistance grid on turbine blades,which can withstand butane flame up to ~1300℃.These results showcase the potential of core-shell structure of the coaxial TFS for high-temperature applications,providing a novel approach to develop high-performance TFS beyond traditional multilayer structure.

关键词： Coaxial printing Core-shell structure Thinfilm strain gauge High-temperature stability

Structural transition,electric transport,and electronic structures in the compressed trilayer nickelate La_(4)Ni_(3)O_(10)

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Science China(Physics,Mechanics & Astronomy) 2024年第11期67卷 9-15页

作者： Jingyuan Li Cui-Qun Chen Chaoxin Huang Yifeng Han Mengwu Huo xing Huang Peiyue Ma Zhengyang Qiu Junfeng Chen Xunwu Hu Lan Chen Tao Xie Bing Shen Hualei Sun dao-xin Yao Meng Wang Center for Neutron Science and Technology Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSchool of PhysicsSun Yat-sen UniversityGuangzhou 510275China Center for Materials of the Universe School of Molecular SciencesArizona State UniversityTempe 85287USA School of Sciences Sun Yat-sen UniversityShenzhen 518107China

Atomic structure and electronic band structure are fundamental properties for understanding the mechanism of superconductivity. Motivated by the discovery of pressure-induced high-temperature superconductivity at 80 K in the bilayer Ruddlesden-Popper nickelate La_(3)Ni_(2)O_(7), the atomic structure and electronic band structure of the trilayer nickelate La_(4)Ni_(3)O_(10) under pressure up to 44.3 GPa are investigated. A structural transition from the monoclinic P2_(1)/a space group to the tetragonal I4/mmm around 12.6-13.4 GPa is identified, accompanied by a drop of resistance below 7 K. Density functional theory calculations suggest that the bonding state of Ni 3d_(z^(2)) orbital rises and crosses the Fermi level at high pressures, which may give rise to possible superconductivity observed in resistance under pressure in La_(4)Ni_(3)O_(10). The trilayer nickelate La_(4)Ni_(3)O_(10) shows some similarities with the bilayer La_(3)Ni_(2)O_(7) and has unique properties, providing a new platform to investigate the underlying mechanism of superconductivity in nickelates.

关键词： La_(4)Ni_(3)O_(10) high pressure synchrotron X-ray diffraction structural transition DFT calculations

Activation of glutamatergic neurons in the somatosensory cortex promotes remyelination in ischemic vascular dementia

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Fundamental Research 2024年第1期4卷 188-198页

作者： Yi-Ting Zhou Da-dao An Yi-xin Xu Ying Zhou Qing-Qing Li Hai-Bin Dai Xiang-Nan Zhang Yi Wang Min Lou Zhong Chen Wei-Wei Hu Department of Pharmacology and Department of Pharmacy of the Second Affiliated Hospital NHC and CAMS Key Laboratory of Medical NeurobiologySchool of Basic Medical SciencesCollege of Pharmaceutical SciencesZhejiang University School of MedicineHangzhou 310058China Department of Pharmacy Sir Run Run Shaw HospitalHangzhou 310012China Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhou 310053China Department of Neurology the Second Affiliated Hospital of Zhejiang UniversitySchool of MedicineHangzhou 310003China

Chronic cerebral hypoperfusion can cause progressive demyelination as well as ischemic vascular dementia,however no effective treatments are ***,based on magnetic resonance imaging studies of patients with white matter damage,we found that this damage is associated with disorganized cortical *** a mouse model,optogenetic activation of glutamatergic neurons in the somatosensory cortex significantly promoted oligodendrocyte progenitor cell(OPC)proliferation,remyelination in the corpus callosum,and recovery of cognitive ability after cerebral *** therapeutic effect of such stimulation was restricted to the upper layers of the cortex,but also spanned a wide time window after ***,enhancement of glutamatergic neuron-OPC functional synaptic connections is required to achieve the protection effect of activating cortical glutamatergic ***,skin stroking,an easier method to translate into clinical practice,activated the somatosensory cortex,thereby promoting OPC proliferation,remyelination and cognitive recovery following cerebral *** summary,we demonstrated that activating glutamatergic neurons in the somatosensory cortex promotes the proliferation of OPCs and remyelination to recover cognitive function after chronic cerebral *** should be noted that this activation may provide new approaches for treating ischemic vascular dementia via the precise regulation of glutamatergic neuron-OPC circuits.

关键词： Chronic cerebral hypoperfusion Optogenetic stimulation Oligodendrocyte progenitor cellIschemic vascular dementia Glutamatergic neuron Remyelination

Recent progress and strategies of cathodes toward polysulfides shuttle restriction for lithium-sulfur batteries

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Rare Metals 2024年第9期43卷 4132-4161页

作者： xing-You Rao Shuang-Fei Xiang Jian Zhou Zhen Zhang Xiang-Yu Xu Yuan-Yuan Xu xin-Chi Zhou Zheng-dao Pan Su-Chong Tan Shi-xing Dong Zhou-Lu Wang Yu-Tong Wu Yun-Lei Zhou Xiang Liu Yi Zhang Shan Jiang School of Energy Sciences and Engineering Nanjing Tech UniversityNanjing 211816China School of Materials Science and Engineering and Institute of Smart Fiber Materials Zhejiang Sci-Tech UniversityHangzhou 310018China JiangSu Sailboat Petrochemical Co. LtdLianyungang 222000China Hangzhou Institute of Technology Xidian UniversityHangzhou 311200China

Lithium-sulfur batteries(LSBs)have already developed into one of the most promising new-generation high-energy density electrochemical energy storage systems with outstanding features including high-energy density,low cost,and environmental ***,the development and commercialization path of LSBs still presents significant limitations and challenges,particularly the notorious shuttle effect triggered by soluble longchain lithium polysulfides(LiPSs),which inevitably leads to low utilization of cathode active sulfur and high battery capacity degradation,short cycle life,*** research efforts have been conducted to develop various sulfur host materials capable of effectively restricting the shuttle *** review firstly introduces the fundamental electrochemical aspects of LSBs,followed by a comprehensive analysis of the mechanism underlying the shuttle effect in Li–S batteries and its profound influence on various battery components as well as the overall battery ***,recent advances and strategies are systematically reviewed,including physical confinement,chemisorption,and catalytic conversion of sulfur hosts for restricting LiPSs shuttle *** interplay mechanisms of sulfur hosts and LiPSs are discussed in detail and the structural advantages of different host materials are ***,key insights for the rational design of advanced host materials for LSBs are provided,and the upcoming challenges and the prospects for sulfur host materials in lithium-sulfur batteries are also explored.

关键词： Lithium-sulfur batteries Polysulfides Shuttle effect Host

重茬地黄土壤酚酸的动态积累及其对地黄生长的影响

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生态学杂志 2009年第4期28卷 660-664页

作者：吴宗伟王明道刘新育陈红歌贾新成河南农业大学生命科学学院郑州450002

为了探究酚酸物质与地黄连作障碍之间的关系,检测了重茬地黄土壤中阿魏酸、香草酸、香草醛和对羟基苯甲酸等4种酚酸物质的积累量,并通过水培条件下添加酚酸,研究了4种酚酸对地黄生长的影响。结果表明:阿魏酸、香草酸和香草醛含量在地黄... 详细信息

为了探究酚酸物质与地黄连作障碍之间的关系,检测了重茬地黄土壤中阿魏酸、香草酸、香草醛和对羟基苯甲酸等4种酚酸物质的积累量,并通过水培条件下添加酚酸,研究了4种酚酸对地黄生长的影响。结果表明:阿魏酸、香草酸和香草醛含量在地黄生长期表现为持续增加,而对羟基苯甲酸含量先升高后降低;外加阿魏酸(8μ***-1)、香草酸(0.8μ***-1)、香草醛(1.2μ***-1)和对羟基苯甲酸(3.0μ***-1)对水培地黄根长、根质量、全株鲜质量和株高有较强的抑制作用;酚酸处理使地黄叶片叶绿素含量降低,除对羟基苯甲酸外差异性极显著;经过酚酸处理的地黄幼苗SOD和POD活性为先升高后下降,丙二醛含量升高,其中阿魏酸的处理使根中酶活性降至最低,根部腐烂死亡。推测4种酚酸可能是造成地黄化感作用的物质。

关键词：地黄连作酚酸物质化感作用