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Solutions for the Prescribing Mean Curvature Equation

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Acta Mathematicae Applicatae Sinica 2008年第3期24卷 497-510页

作者： Dao-min cao Shuang-jie Peng Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China School of Mathematics and Statistics Central China Normal University Wuhan 430079 China

By variational methods, for a kind of Yamabe problem whose scalar curvature vanishes in the unit ball BN and on the boundary S^N-1 the mean curvature is prescribed, we construct multi-peak solutions whose maxima are located on the boundary as the parameter tends to 0^＋ under certain assumptions. We also obtain the asymptotic behaviors of the solutions.

关键词： Mean curvature critical point concentrating solutions

The anti-Temperature-vibration properties of viscoelastic anticorrosive tape

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Petroleum Science 2022年第5期19卷 2413-2419页

作者： Hai-Liang Nie Wei-Feng Ma Xiao-Wei Hu Wei Dang jun-jie Ren Ke Wang jun cao Tian Yao Xiao-Bin Liang Institute of Safety Assessment and Integrity State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment MaterialsCNPC Tubular Goods Research InstituteXi'an710077China No.2 Oil Extraction Plant Changqing Oilfield BranchPetroChinaGansu745100China

Viscoelastic anticorrosive tape is extensively used for repairing anticorrosive layers on compressor outlet pipelines in the oil and gas ***,there is no relevant research on the coupling effect of temperature and vibration on the performance of viscoelastic anticorrosive *** this paper,acceleration tests of temperature and vibration coupling conditions were conducted to investigate the performance of viscoelastic anticorrosive *** temperature and vibration treatment,the specimens showed wide variance in thickness,and the adhesion and chemical soaking resistance of the tape was ***,the viscoelastic anticorrosive tape still showed high *** to theoretical calculations,the tested viscoelastic body can repair pipes with a maximum diameter of 903 ***,this viscoelastic anticorrosive tape is suitable for the compressor outlets of buried pipelines with diameters smaller than 903 *** research in this paper provides a method and basis for the selection of repairing materials for the anticorrosion coatings of compressor outlet pipelines.

关键词： Station Compressor outlet Anticorrosive coating Viscoelastic anticorrosive tape

Lipid concentration and composition in xylem sap of woody angiosperms from a tropical savanna and a seasonal rainforest

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Plant Diversity 2024年第1期46卷 126-133页

作者： Ling-Bo Huang Xinyi Guan Amy Ny Aina Aritsara jun-jie Zhu Steven Jansen Kun-Fang cao State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources Guangxi Key Laboratory of Forest Ecology and ConservationGuangxi UniversityDaxuedong Road 100NanningGuangxi 530004China Institute of Botany Ulm UniversityAlbert-Einstein-Allee 11Ulm89081Germany

Lipids may play an important role in preventing gas embolisms by coating nanobubbles in xylem *** studies on xylem sap lipids have been reported for temperate plants,and it remain unclear whether sap lipids have adaptational significance in tropical *** this study,we quantify the lipid composition of xylem sap for angiosperm species from a tropical savanna(seven species)and a seasonal rainforest(five species)using mass *** found that all twelve species studied contained lipids in their xylem sap,including galactolipids,phospholipids and triacylglycerol,with a total lipid concentration ranging from 0.09 to 0.26 nmol/*** was no difference in lipid concentration or composition between plants from the two sites,and the lipid concentration was negatively related to species’open vessel ***,savanna species showed little variation in lipid composition between the dry and the rainy *** results support the hypothesis that xylem sap lipids are derived from the cytoplasm of individual conduit cells,remain trapped inside individual conduits,and undergo few changes in composition over consecutive seasons.A xylem sap lipidomic data set,which includes 12 tropical tree species from this study and 11 temperate tree species from literature,revealed no phylogenetic signals in lipid composition for these *** study fills a knowledge gap in the lipid content of xylem sap in tropical trees and provides additional support for their common distribution in xylem sap of woody *** appears that xylem sap lipids have no adaptive significance.

关键词： Xylem sap Lipids Tropical savanna Tropical rainforest Vessels

Hydrodynamic Behavior of Fluid Resonance Between Twin Boxes in Moonpool with Various Edge Profiles Under Wave Actions

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China Ocean Engineering 2023年第4期37卷 547-557页

作者： LAN jun-jie JIANG Sheng-chao GAO jun-liang Faculty of Vehicle Engineering and Mechanics Dalian University of TechnologyDalian 116024China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Fluid resonance in moonpool formed by twin boxes under wave actions is investigated by using a viscous numerical wave flume with ReNormalization Group(RNG)turbulent *** accuracy of the numerical model is validated by available experimental *** types of edge profiles,the sharp edge,concave edge and convex edge are *** simulations show that the normalized resonant amplitude in moonpool decreases with the decrease of moonpool opening or increase of incident wave *** increased reflection coefficients are the major reason for the phenomena,implying less wave energy is able to support the wave resonance in *** the increase of incident wave height,the energy coefficients increase for convex edges around resonant fre-quency,which are oppositely with those of sharp and concave *** flow patterns of the wave resonance in the vicinity of the moonpool entrance are also identified,which are mainly dependent on the edge profiles.

关键词： moonpool wave resonance corner shape RNG turbulent model OpenFOAM® flow pattern

A novel robust design method for improving stability of optimized structures

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Acta Mechanica Sinica 2015年第1期31卷 104-111页

作者： Ming-jie cao Hai-Tao Ma Peng Wei State Key Laboratory of Subtropical Building Science Department of Civil Engineering South China University of Technology State Key Laboratory of Structural Analysis of Industrial Equipment Dalian University of Technology

It is known that structural optimization may lead to designs of structures having low stability and sometimes even kinematically unstable designs. This paper presents a robust design method for improving the stability of opti mized structures. A new approach is proposed, in which cer tain perturbation loads are introduced and the corresponding compliance is added to the objective function as a penaliza tion. The stability of the optimized structures can thus be improved substantially by considering structural responses to the original and the introduced loads. Numerical exam ples show the simplicity and effectiveness of the proposed method.

关键词： Structural optimization Robust design Penal-ization Perturbation loads

Mechanical properties and failure modes of stratified backfill under triaxial cyclic loading and unloading

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International Journal of Mining Science and Technology 2019年第5期29卷 809-814页

作者： Wang jie Song Weidong cao Shuai Tan Yuye School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China State Key Laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education Beijing 100083China

Multiple filling of gobs will lead to a layered structure of the *** explore the influence of layering structure on the mechanical properties and failure modes of backfill,different backfill specimens were prepared with a cement/sand ratio of 1:4,a slurry concentration of 75%,and backfilling times of 1,2,3 and 4,*** cyclic loading and unloading experiments were carried *** results show that with an increase in backfilling time,the peak strength of backfill decreases as a polynomial function and the peak strain increases as an exponential *** cyclic load enhances the linear characteristic of backfill *** loading and unloading deformation moduli have a linear negative correlation with the backfilling *** unloading deformation modulus is always slightly higher than the loading deformation *** failure modes of stratified backfill are mainly characterized by conjugate shear failure at the upper layer and tensile failure across the layer plane,and there is usually no damage in the lower layer away from the loading area.

关键词： Stratified backfill Triaxial cyclic loading and unloading Mechanical properties Failure modes Deformation modulus

Effect of rotor-mounted protrusion on sealing performance and flow structure in rotor-stator cavity

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Chinese Journal of Aeronautics 2018年第11期31卷 2057-2072页

作者： Nan cao Xiang LUO Zeyu WU jie WEN National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics School of Energy and Power EngineeringBeihang UniversityBeijing 100083China Collaborative Innovation Center for Advanced Aero-Engine Beijing 100083China

This paper presents an experimental investigation on the effect of protrusion radial position and height on the sealing performance and flow structure in the rotor-stator cavity. The rotormounted protrusions are assembled at three radial positions and are set to three heights. The cavity is equipped with three rim seals: a radial seal, an axial seal and a seal with double fins on the *** annulus Reynolds number is set at 4:39 ×10;and the rotational Reynolds number ranges from 7:51×10;to 1:20×10;. Heat and mass transfer analogy is applied. Pressure and CO;concentration are measured. The experimental results show that in cavities with different rim seals, radial distributions of the sealing efficiency, pressure and swirl ratio are basically the same. The sealing performance is improved by protrusions compared with the cavity without protrusion and improves with the increase of protrusion radial position and height. The effect of protrusion increases with the increase of the rotational Reynolds number. The windage loss and the flow resistance introduced by protrusions are investigated. It is found that induced windage loss and flow resistance decrease with the increase of protrusion radial position but increase with the protrusion height.

关键词： Height Protrusion Radial position Rim seal Sealing performance

Fabrication of polymer/fluoride-containing salts blend composite membranes for CO_2 separation

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Journal of Natural Gas Chemistry 2010年第6期19卷 560-566页

作者： Pengfei Ji Yiming cao Xingming jie Quan Yuan Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 Liaoning China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Poly （N,N-dimethylaminoethyl methacrylate）-poly （ethylene glycol methyl ether methacrylate）（PDMAEMA-PEGMEMA） and cesium fluoride （CsF） were blended and used as the separation material of composite *** fiber composite membranes were fabricated by coating the blend on polysulfone （PSf） hollow fiber *** of fluorine ion improved the separation performance of the *** concentration of coating solution was adjusted to obtain a membrane with high *** composite membrane showed good performance with the CO2 permeance of 30.4 GPU （1 GPU=10-6 cm3 （STP）/（cm 2 s cmHg））,and selectivities to CO2/N2,CO2/CH4,CO2/H2 and O2/N2 of 47.2,37.6,1.75 and 4.70,*** fluoride （KF）,due to its low cost,was also used as a substitute of CsF to prepare composite membrane and the permeation data showed that CsF can be replaced by *** effect of operating temperature on the permeation properties of the composite membrane was also investigated.

关键词： blend composite membrane coating CO2 separation hollow fiber

Effect of water injection on hydrogen generation during severe accident in PWR

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Nuclear Science and Techniques 2009年第5期20卷 312-316页

作者： TAO jun cao Xuewu School of Mechanical and Power Engineering Shanghai Jiao Tong University Shanghai 200240 China

Effect of water injection on hydrogen generation during severe accident in a 1000 MWe pressurized water reactor was studied. The analyses were carried out with different water injection rates at different core damage stages. The core can be quenched and accident progression can be terminated by water injection at the time before cohesive core debris is formed at lower core region. Hydrogen generation rate decreases with water injection into the core at the peak core temperature of 1700 K, because the core is quenched and reflooded quickly. The water injection at the peak core temperature of 1900 K, the hydrogen generation rate increases at low injection rates of the water, as the core is quenched slowly and the core remains in uncovered condition at high temperatures for a longer time than the situation of high injection rate. At peak core temperature of 2100–2300 K, the Hydrogen generation rate increases by water injection because of the steam serving to the high temperature steam-starved core. Hydrogen generation rate increases significantly after water injection into the core at peak core temperature of 2500 K because of the steam serving to the relocating Zr-U-O mixture. Almost no hydrogen generation can be seen in base case after formation of the molten pool at the lower core region. However, hydrogen is generated if water is injected into the molten pool, because steam serves to the crust supporting the molten pool. Reactor coolant system (RCS) depressurization by opening power operated relief valves has important effect on hydrogen generation. Special attention should be paid to hydrogen generation enhancement caused by RCS depressurization.

关键词： PWR 核技术研究发展 RCS