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Effects of temperature distribution and level on heat transfer on a rotating free disk

航空动力学报 2011年第6期26卷 1310-1320页

作者： ZHAO Xi XU guo-qiang luo Xiang National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100191 China

In gas turbine engines,with the existence of the intense forced convection and significant buoyancy effects,temperature distribution and level on turbine or compressor disks affect the heat transfer characteristics *** this paper,numerical simulations were performed to analyze these influences for a free disk,with the laminar and turbulent flow *** influences of temperature distribution on the heat transfer were observed by using incompressible cooling air,and temperature profiles of nth order monomial and polynomial were assumed on the *** analysis revealed that the heat transfer for two flow states on the free disk is determined by the exponent n of the monomial profile when specifying the rotating Reynolds number;for an arbitrary polynomial profile,the local Nusselt number can be deduced from results of monomial *** study the effects of temperature level on heat transfer singly,monomial profiles were used and the local Nusselt number of compressible and incompressible cooling air were *** both for two flow states,the following conclusions could be drawn: the relative difference of local Nusselt number is mainly controlled by nondimensional local temperature difference,and almost independent of the monomial's coefficient C,exponent n and the rotating Reynolds ***,a correction method for heat transfer of the free disk is presented and verified computationally,with which the local Nusselt number,obtained with a uniform and low temperature profile,can be revised by arbitrary distribution and high temperature magnitude.

关键词： thermal boundary condition temperature boundary condition rotating disk free disk heat transfer

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Characterization of diffusion-bonded joint between Al and Mg using a Ni interlayer

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Rare Metals 2016年第7期35卷 537-542页

作者： Jian Zhang guo-qiang luo qiang Shen Lian-Meng Zhang Zhi-Jun Huang Research and Development Center of Wuhan Iron and Steel(Group)Corporation Wuhan 430080China State Key Laboratory of Advanced for Materials Synthesis andProcessing Wuhan University of TechnologyWuhan 430070China

Aluminum and magnesium were joined through diffusion bonding using Ni interlayer. The micro- structure and mechanical performance of the A1/Ni/Mg joints at different temperatures was investigated by means of scanning electron microscope （SEM）, electro-probe microanalyzer （EPMA）, X-ray diffraction （XRD）, Vickers hardness testing, and shear testing. The results show that the addition of Ni interlayer eliminates the formation of Mg-A1 intermetallic compounds and improves the bonding strength of the A1/Mg joints. The AI/Ni/Mg joints are formed by the diffusion of A1, Ni and Mg, Ni. The microstructure at the joint interface from A1 side to Mg side is A1 substrate/A1-Ni reaction layer/Ni interlayer/Mg-Ni reaction layer/Mg substrate multilayer structure. The mi- crohardness of the Mg-Ni reaction layer has the largest value of HV 255.0 owing to the existence of Mg2Ni phase. With the increase of bonding temperature, the shear strength of the joints increases firstly and then decreases. The A1/Ni/Mg joint bonds at 713 K for 90 min, exhibiting the maximum shear strength of 20.5 MPa, which is greater than that of bonding joint bonded directly or with Ag interlayer. The fracture of the joints takes place at the Mg- Ni interface rather than the A1-Ni interface, and the frac- ture way of the joints is brittle fracture.

关键词： A1-Mg Ni foil Diffusion bonding Microstructure Shear strength

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Development and calibration of heat transfer coefficient sensor for rotational state

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航空动力学报 2011年第12期26卷 2684-2690页

作者： QUAN Yong-kai XU guo-qiang luo Xiang ZHANG Da （School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100000 China

A novel heat transfer coefficient sensor is introduced and the design,manufacture,and calibration are *** intended application of this instrument was on a high rotational speed test *** the experiments,the heat transfer coefficient sensor was calibrated under static state and rotational state *** calibration under the static state was accomplished in a pipe: the inside diameter(ID) was 0.048m and the total length was 4m,the distance between the sensor and the inlet of the pipe was 3.5m;the standard value was measured using a self-made *** calibration under the rotational state was accomplished using a rotating disc: the diameter and thickness of the stainless disc were 800mm and 25mm,respectively;the sensor was installed at the location of r=250mm;the rotating disc driven by a 30kW direct current motor can supply the maximum rotational speed of 3000r/*** standard value under rotational state was provided by an approximate empirical *** results show that the designed sensor can measure heat transfer coefficient directly under rotational state and static state with good accuracy and stability;the correlation factor of K are constant under static state and rotational state.

关键词： rotational state steady method heat transfer coefficient sentor calibration

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Synthesis and Compressive Response of Microcellular Foams Fabricated from Thermally Expandable Microspheres

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Chinese Journal of Polymer Science 2019年第3期37卷 279-288页

作者： Rui-Zhi Zhang Ju Chen Mao-Wei Huang Jian Zhang guo-qiang luo Bao-Zhen Wang Mei-Juan Li qiang Shen Lian-Meng Zhang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology School of Civil and Hydraulic Engineering Hefei University of Technology School of Chemistry Chemical Engineering and Life Sciences Wuhan University of Technology

Cellular foams are widely applied as protective and energy absorption materials in both civil and military fields. A facile and simple one-step heating method to fabricate polymeric foams is measured by adopting thermally expandable microspheres(TEMs). The ideal foaming parameters for various density foams were determined. Moreover, a mechanical testing machine and split Hopkinson bar(SHPB) were utilized to explore the quasi-static and dynamic compressive properties. Results showed that the cell sizes of the as-prepared TEMs foams were in the micrometer range of 11 μm to 20 μm with a uniform cell size distribution. All the foams exhibited good compressive behavior under both quasi-static and high strain rate conditions, and were related to both foam densities and strain rates. The compressive strength of the TEMs foams at 8400s^(-1) was up to 4 times higher than that at 10^(-4)s^(-1). The effects exerted by the strain rate and sample density were evaluated by a power law equation. With increasing density, the strain rate effect was more prominent. At quasistatic strain rates below 3000s^(-1) regime, initial cell wall buckling and subsequent cellular structure flattening were the main failure mechanisms. However, in the high strain rate(HSR) regime(above 5000s^(-1)), the foams were split into pieces by the following transverse inertia force.

关键词： Thermally expandable microspheres Compressive response Split Hopkinson bar(SHPB) Microcellular Failure mechanism

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Spontaneous Infection and Periodic Evolving of Domain in a Diffusive SIS Epidemic Model

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 164-191页

作者： qiang Wen guo-qiang Ren Bin Liu School of Mathematics and Statistics Huazhong University of Science and TechnologyWuhan430074China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and TechnologyWuhan430074China

In this paper, we consider a susceptible-infective-susceptible(SIS) reaction-diffusion epidemic model with spontaneous infection and logistic source in a periodically evolving domain. Using the iterative technique,the uniform boundedness of solution is established. In addition, the spatial-temporal risk index R0(ρ) depending on the domain evolution rate ρ(t) as well as its analytical properties are discussed. The monotonicity of R0(ρ)with respect to the diffusion coefficients of the infected dI, the spontaneous infection rate η(ρ(t)y) and interval length L is investigated under appropriate conditions. Further, the existence and asymptotic behavior of periodic endemic equilibria are explored by upper and lower solution method. Finally, some numerical simulations are presented to illustrate our analytical results. Our results provide valuable information for disease control and prevention.

关键词： diffusive SIS model spontaneous infection periodically evolving domain periodic endemic equilibrium

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Recent Advances in Pd-Catalyzed Reactions Involving the “On-Water” Mechanism

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Chinese Journal of Chemistry 2024年第5期42卷 533-542页

作者： Dong Wei guo-qiang Lin State Key Laboratory of Systems Medicine for Cancer Shanghai Cancer InstituteShanghai Key Laboratory of Systems Regulation and Clinical Translation for CancerRen Ji HospitalShanghai Jiao Tong University School of MedicineShanghai200127 China State Key Laboratory of Chemical Biology Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai200032 China

As the chemical industry grapples with the need for more eco-friendly practices,the use of water as a reaction medium is gaining attraction in organic *** mini-review delves into Pd-catalyzed reactions that utilize the "on-water" mechanism,spanning from 2019 to late *** reactions are neatly categorized into several types: (A) Catalytic C—H activations,(B) Mizoroki- Heck-type reactions,(C) Suzuki-Miyaura reactions,and (D) Cyclization *** showcasing the potential of water as a sustainable reaction medium for organic transformations,these reactions leave no doubt about the importance of embracing eco-friendly practices in the chemical *** Scientists In 1980,a seminal work by Breslow et *** an acceleration of reaction rate in the Diels-Alder *** and co-workers noted a significant increase in the rate of the [2σ+2σ+2π] cycloaddition of quadricyclane and dimethyl azodicarboxylate (DMAD) when the reaction was conducted in water,as opposed to when it was carried out in organic *** term "on-water" was then coined to describe this *** strategy was further expanded to transition-metal catalyzed transformations by Ackermann in ***,Varma and Leazer disclosed a Pd-catalyzed Mizoroki-Heck type arylation of alkenes with diaryliodonium salts “on-water”.The enantioselective version of "on-water" process was not realized until 2014 by the Zhou *** on,the Schaub group described a Pd-catalyzed Suzuki–Miyaura coupling reaction of electron-poor aryl chlorides with water,using only 50 ppm of catalyst *** recently,Liu and Lin extended the "on-water" strategy to Pd-catalyzed double Mizoroki-Heck *** mini-review has focused on Pd-catalyzed reactions involving the “on-water” mechanism.

关键词： Pd-catalyzed “On-water” Green chemistry Aqueous reactions Mechanism Methodology and reactions Mizoroki-Heck reaction Cross-coupling

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Indian monsoon drove the dispersal of the thoracica group of Scytodes spitting spiders

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Zoological Research 2024年第1期45卷 152-159页

作者： Yu-Fa luo Shu-qiang Li School of Life and Environmental Sciences Shaoxing UniversityShaoxingZhejiang 312000China Key Laboratory of Zoological Systematics and Evolution Institute of ZoologyChinese Academy of SciencesBeijing 100101China Southeast Asia Biodiversity Research Institute Chinese Academy of SciencesYezinNay Pyi Taw 05282Myanmar

We examined the global biogeography of the Scytodes thoracica group of spitting spiders based on 23 years of sampling at the species level(61 species in the thoracica group and 84 species of Scytodes)using DNA data from six *** results indicated that the thoracica group initially dispersed from Southeast Asia to East Africa between 46.5 and 33.0 million years ago,and dispersal events intensified between Southeast/South Asia and East/South Africa from the early to late *** timing of these events indicates that Asian-African faunal exchange of the thoracica group was driven by the Indian monsoon,and the pattern of dispersal suggests that colonialization took root when the Indian monsoon shifted from a North-South direction to an East-West direction from the middle Eocene.

关键词： Geological event Climate change Ballooning organism Faunal exchange Species distribution

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In situ anchoring in carbon matrix of Bi_(2)O_(2)CO_(3) as a high-performance anode material for Li-ion batteries

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Rare Metals 2024年第8期43卷 3634-3646页

作者： Pu-qiang He Jun guo Hui Huang Zhong-Cheng guo Faculty of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming 650093China Research Center of Metallurgical Electrode Materials Engineering Technology Kunming 650106China Kunming Hendera Science and Technology Co. Ltd.Kunming 650106China

Bismuth-based anode materials have been regarded as promising Li-ion batteries due to their high theoretical ***,their low conductivity and associated volume expansion inhabited their *** this work,Bi_(2)O_(2)CO_(3)@C composites were successfully synthesized by in situ anchoring of flower-like Bi_(2)O_(2)CO_(3) nanosheets on a carbon-based substrate via *** unique composited structure of Bi_2O_(2)-CO_(3)@C leads to a stable specific capacity of 547 mAh·g^(-1)after 100 cycles at a current density of 0.1 A·g^(-1).Notably,it demonstrates excellent rate capability with a specific capacity of 210 mAh·g^(-1)at 5 A·g^(-1).After 550 cycles at a current density of 0.5 A·g^(-1),a high reversible capacity of nearly 400 mAh·g^(-1)was ***,in situ X-ray diffraction measurements clearly demonstrate the conversion between Bi and Li_(3)Bi during alloying/dealloying,confirming the good electrochemical reversibility of the materials for Li *** reaction kinetics of Bi_(2)O_(2)CO_(3)@C were further investigated using galvanostatic intermittent titration ***,Bi_2O_(2)-CO_(3)@C exhibited excellent long-term stability,maintaining its high reversible capacity for over 200 cycles at a current density of 0.5 A·g^(-1)in a full cell configuration using Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) as the cathode *** result further underscores its promising potential for lithium-ion *** work may provide inspiration for the design of alloy-type negative electrode materials for high-performance rechargeable batteries.

关键词： Bi_(2)O_(2)CO_(3) Composite materials Anode materials Full batteries

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Decomposition of pre-existing Au–P clusters induced in situ a-Fe grains uniformization in Fe–P-based nanocrystalline alloys

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Rare Metals 2024年第10期43卷 5242-5255页

作者： Min-Hao Han Cheng Sun guo-guo Xi Yang Meng qiang luo Xue-Qian Yu Wen-Feng Zhang Hao Liu Hong-Jie Xu Tao Zhang Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang University Laboratory of Functional Fiber Materials Institute of Bast Fiber CropsChinese Academy of Agricultural Science School of Materials Science and Engineering Jiangsu Key Laboratory for Advanced Metallic MaterialsSoutheast University Institute for Advanced Materials North China Electric Power University Center for Advanced Analysis and Computational Science Zhengzhou University

In Fe-based amorphous-/nanocrystalline ribbons,the uniformization and refinement of a-Fe grains are key aspects for optimizing their soft magnetic and mechanical ***,the Fe–P–C–B nanocrystalline alloy system was selected for *** produced as-spun ribbons with pre-existing nanocrystals through melt-quenching and then obtained a well-distributed a-Fe nanocrystalline structure through annealing below the first crystallization onset temperature （633 K）resulting in excellent magnetic properties (saturation magnetization of 1.65 T and coercivity of 1.6 A·m-1)ultra-wide annealing temperature window （from 613 to 733 K）,and extremely high annealing stability （up to 480 min at 633 K）.Furthermore,we propose a new in situ two-step mechanism for the uniformization of a-Fe nanocrystals,which is separately induced by the decomposition of the Au–P clusters and the pre-existing a-Fe nanocrystals during *** work underscores the crucial significance of micro-alloying via metastable clusters primarily influenced by metal-phosphide interactions in the process of refining a-Fe ***,i introduces a new principle for optimizing the comprehensive properties of Fe-based amorphous/nanocrystalline alloys.

关键词： Fe-based nanocrystalline alloys In-situ nano-crystallization Micro-alloying Soft magnetic property

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Homoclinic Solutions for a Class of Perturbed Fractional Hamiltonian Systems with Subquadratic Conditions

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1177-1196页

作者： Ying luo Fei guo Yan LIU School of Mathematics Tianjin UniversityTianjin 300354P.R.China Tianjin Key Laboratory of Brain-Inspired Intelligence Technology Tianjin300354P.R.China

In this paper,we consider the following perturbed fractional Hamiltonian systems{tD_(∞)^(α)(_(-∞)D_(t)^(α)u(t))+L(t)u(t)=■_(u)W(t,u(t))+■(u)G(t,u(t)),t∈R,u∈H^(α)(R,R^(N)),whereα∈(1/2,1],L∈C(R,R^(N×N))is symmetric and not necessarily required to be positive definite,W∈C1(R×R^(N,R))is locally subquadratic and locally even near the origin,and perturbed term G∈C1(R×R^(N,R))maybe has no parity in *** the perturbed method improved by the authors,a sequence of nontrivial homo clinic solutions is obtained,which generalizes previous results.

关键词： Perturbed fractional Hamiltonian systems subquadratic condition perturbed method homoclinic solutions multiplicity

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