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SIMULATION OF THERMAL TRANSPORT IN AQUIFER:A GWHP SYSTEM IN CHENGDU,CHINA

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Journal of Hydrodynamics 2009年第5期21卷 647-657页

作者： zhou Yan-zhang zhou Zhi-fang Institute of Groundwater Science and Engineering Hohai University Nanjing 210098 China

With an established convection-dispersion model for the thermal transport in aquifer, the thermal transport processes in an unconfined aquifer of a Groundwater Heat Pump （GWHP） system in Chengdu, China, are simulated with double-well intervals and cooling-load design fluctuations in summer running period under special groundwater flow and heat source conditions, and the stage-characteristics of the thermal transport in the aquifer are investigated in the running cycle （1 year） numerically. The results show that the thermal transport in the aquifer is closely related to the distance between pumping and injecting wells and the cooling-load design fluctuations, especially, to the cycling water volume. The thermal transport in the aquifer sees different characteristics in the two states in the pumping-recharging stages in summer/winter and the storing stages in spring/autumn. With the hydro-geologic theory and the numerical model, the effect of the groundwater-flow on the thermal transport in the unconfined aquifer is discussed.

关键词： Groundwater Heat Pump (GWHP) thermal transport in aquifer numerical simulation groundwater flow

Systematic diesel molecular performance evaluation based on quantitative structure-property relationship model

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Petroleum Science 2022年第2期19卷 809-818页

作者： Guang-Qing Cai Lin-zhou zhang State Key Laboratory of Heavy Oil Processing Petroleum Molecular Engineering Center(PMEC)China University of PetroleumBeijing 102249China

The production and separation of optimal molecules in diesel fuels require a systematic property evaluation for the containing *** paper evaluates the diesel molecules based on four key quality indicators:low-temperature fluidity,cleanliness,ignition,and power *** established the corresponding quantitative structure-property relationship models for corresponding properties,which are freezing point,yield sooting index,cetane number,and combustion *** models were applied for the screening of the high-performance molecules that is suitable for *** molecular performance distribution of the conventional diesel and biodiesel were also ***,we analyzed the effect of different transformation paths on molecular properties,giving guidance on the conversion process design.

关键词： Diesel Optimal molecules QSPR Molecular screening

Optimization and Parameters Estimation in Ultrasonic Echo Problems Using Modified Artificial Bee Colony Algorithm

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Journal of Bionic Engineering 2015年第1期12卷 160-169页

作者： Jinghua zhou Xiaofeng zhang Guangbin zhang Dongmei Chen Ultrasonic Key Laboratory of Shaanxi Province College of Physics and Information Technology Shaanxi Normal University Xi'an Shaanxi 710119 China

The patterns of ultrasonic backscattered echoes represent valuable information pertaining to the geometric shape, size, and orientation of the reflectors as well as the microstructure of the propagation path. Accurate estimation of the ultrasonic echo pattern is essential in determining the object or propagation path properties. This paper proposes a parameter estimation method for ultrasonic echoes based on Artificial Bee Colony （ABC） algorithm which is one of the most recent swarm intelligence based algorithms. A modified ABC （MABC） algorithm is given by adding an adjusting factor to the neighborhood search formula of traditional ABC algorithm in order to enhance its performance. The algorithm could overcome the impact of different search range on estimation accuracy to solve the multi-dimensional parameter optimization problems. The performance of the MABC algorithm is demonstrated by numerical simulation and ultrasonic detection experiments. Results show that MABC not only can accurately estimate various parameters of the ultrasonic echoes, but also can achieve the optimal solution in the global scope. The proposed algorithm also has the advantages of fast convergence speed, short running time and real-time parameters esti- mation.

关键词： artificial bee colony algorithm swarm intelligence global optimization ultrasonic echoes ultrasonic testing

On the Kahler-Ricci Flow on Projective Manifolds of General Type

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Chinese Annals of Mathematics,Series B 2006年第2期27卷 179-192页

作者： Gang TIAN zhou zhang Dedicated to the memory of Shiing-Shen Chern

This note concerns the global existence and convergence of the solution for Kahler-Ricci flow equation when the canonical class, Kx, is numerically effective and big. We clarify some known results regarding this flow ... 详细信息

关键词： Geometric evolution equations Minimal model program

Improved Reliability Analysis Method Based on the Failure Assessment Diagram

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Chinese Journal of Mechanical Engineering 2012年第4期25卷 832-837页

作者： zhou Yu zhang Zheng ZHONG Qunpeng School of Material Science and Engineering Beihang University Beijing 100191 China

With the uncertainties related to operating conditions,in-service non-destructive testing（NDT） measurements and material properties considered in the structural integrity assessment,probabilistic analysis based on the failure assessment diagram（FAD） approach has recently become an important ***,the point density revealing the probabilistic distribution characteristics of the assessment points is usually *** obtain more detailed and direct knowledge from the reliability analysis,an improved probabilistic fracture mechanics（PFM） assessment method is *** integrating 2D kernel density estimation（KDE） technology into the traditional probabilistic assessment,the probabilistic density of the randomly distributed assessment points is visualized in the assessment ***,a modified interval sensitivity analysis is implemented and compared with probabilistic sensitivity *** improved reliability analysis method is applied to the assessment of a high pressure pipe containing an axial internal semi-elliptical surface *** results indicate that these two methods can give consistent sensitivities of input parameters,but the interval sensitivity analysis is computationally more ***,the point density distribution and its contour are plotted in the FAD,thereby better revealing the characteristics of PFM *** study provides a powerful tool for the reliability analysis of critical structures.

关键词： reliability analysis failure assessment diagram probabilistic fracture mechanics kernel density estimation sensitivity analysis

Large-eddy structures of turbulent swirling flows and methane-air swirling diffusion combustion

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Acta Mechanica Sinica 2005年第5期21卷 419-424页

作者： Liyuan Hu Lixing zhou Jian zhang Department of Engineering Mechanics Tsinghua University Beijing100084 China

Turbulent swirling flows and methane-air swirling diffusion combustion are studied by large-eddy simulation （LES） using a Smagorinsky-Lilly subgrid scale turbulence model and a second-order moment （SOM） SGS combustion model, and also by RANS modeling using the Reynolds Stress equation model with the IPCM＋wall and IPCM pressure-strain models and SOM combustion model. The LES statistical results for swirling flows give good agreement with the experimental results, indicating that the adopted subgrid-scale turbulence model is suitable for swirling flows. The LES instantaneous results show the complex vortex shedding pattern in swirling flows. The initially formed large vortex structures soon break up in swirling flows. The LES statistical results of combustion modeling are near the experimental results and are as good as the RANS-SOM modeling results. The LES results show that the size and range of large vortex structures in swirling combustion are different from those of isothermal swirling flows, and the chemical reaction is intensified by the large-eddy vortex structures.

关键词： Swirling combustion . Swirling flows .Large-eddy simulation

Effect of strong magnetic field on isothermal transformation of degenerate pearlite in an Fe-C-Mo alloy

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Acta Metallurgica Sinica(English Letters) 2010年第4期23卷 248-254页

作者： Zhenni zhou Cuohong zhang Kaiming WU Hubei Province Key Laboratory of Systems Science in Metallurgical Processing Institute of Advanced Steels and Welding Technology Wuhan University of Science and Technology Wuhan 430081 China

The pearlite transformation in a Mo-containing iron alloy was investigated under 12 T magnetic field. The pearlite transformation was accelerated owing to the application of a strong magnetic field. Pearlite was of degenerated morphology without the presence of a strong magnetic field; but the degeneracy of pearlite is reduced when a strong magnetic field was applied, which may be attributed to the effect of strong magnetic field on faster carbon diffusion and less molybdenum segregation caused by a strong magnetic

关键词： field Steels Pearlite Phase transformation Strong magnetic field

Taxonomy of the genus Dianous （Coleoptera： Staphylinidae： Steninae） in China and zoogeographic patterns of its distribution

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Insect Science 2011年第3期18卷 363-378页

作者： Kai Shi Hong-zhang zhou Key Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing College of Agriculture Inner Mongolia University for the Nationalities Tongliao Inner Mongolia Autonomous Region China

Ninety-six species of the rove beetle genus Dianous Leach, 1819 have been recorded in China. In this paper, we describe a new species, D. poecilus n. sp. from Yunnan, and record D. viriditinctus （Champion, 1920） for the first time from China. To facilitate identification of species, species groups and/or species complexes, we compiled a new version of keys, including all species of Dianous hitherto recorded in the territory of China. Moreover, main patterns of geographical distribution are outlined for the world Dianous fauna of this genus.

关键词： China Dianous distributional patterns new species Staphylinidae

NUMERICAL MODELING OF TURBULENTEVAPORATING GAS-DROPLET TWO-PHASE FLOWS IN AN AFTERBURNER DIFFUSOR OF TURBO-FAN JET ENGINES

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Chinese Journal of Aeronautics 1990年第4期5卷 258-265页

作者： zhou Lixing and zhang JianTsinghua University

The two-dimensional turbulent evaporating gas-droplet two-phase flows in an afterburner diffusor of turbo-fan jet engines are simulated by the k-ε turbulence model and the particle trajectory model. Comparison of predicted gas velocity and temperature distributions with experimental results for the cases without liquid spray shows pretty good agreement. Gas-droplet two-phase flow predictions give plausible droplet trajectories, fuel-vapor concentration distribution, gas-phase velocity and temperature field in presence of liquid droplets. One run of computation with this method is made for a particular afterburner. The results indicate that the location of the atomizers is not favorable to flame stabilization and combustion efficiency. The proposed numerical modeling can also be adopted for optimization design and performance evaluation of afterburner combustors of turbo-fan jet engines.

关键词： NUMERICAL MODELING OF TURBULENTEVAPORATING GAS-DROPLET TWO-PHASE FLOWS IN AN AFTERBURNER DIFFUSOR OF TURBO-FAN JET ENGINES JET GAS