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Journal of Iron and Steel Research International 2012年第S2期19卷 713-716页

作者： Mcepanskis A Jakovis E Baake B Nacke Laboratory for Mathematical Modelling of Environmental and Technological Processes University of Latvia Institute of Electrotechnology Leibniz University of Hanover

The paper refers to the dynamics of solid inclusion in the turbulent flow of liquid metal in induction furnaces. The numerical analysis is carried out adopting LES-based Euler-Lagrange approach in the limit of dilute *** admixing of carbon particles in induction crucible furnace from the open surface of a melt is *** behaviour of the particles in the bulk of the flow is illustrated as well as compared with the industrial observation of the open surface of the *** paper also contains the description of the novel experimental technique,which is proposed for the verification of the numerical *** experiment deals with ferromagnetic particles in the flow of Wood's metal in the small induction crucible *** experiment confirms the satisfactory agreement with the numerical results.

关键词： induction furnaces turbulent flow solid inclusions carbon LES experimental verification

Influence of Channel and Yoke Design and Clogging on Turbulent Flow and Heat Exchange in Induction Channel Furnaces

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Journal of Iron and Steel Research International 2012年第S2期19卷 749-753页

作者： JAKOVICS Andris PAVLOVS Sergejs BOSNYAKS Dmitrijs SPITANS Sergejs BAAKE Egbert NACKE Bernard Laboratory for Mathematical Modelling of Environmental and Technological Processes University of Latvia Institute of Electrotechnology Leibniz University of Hannover

Low frequency oscillations of temperature field in the industrial induction channel furnace(ICF)with symmetrical and widened channel branches as well as different iron yoke positions are obtained using Large Eddy Simulation(LES)*** application of k-ω Shear Stress Transport(SST)turbulence model for computations of ICF with typical clogging shapes shows their influence on temperature and induced Joule heat power distributions,which are to be precise in LES study.

关键词： ICF LES SST low-frequency oscillations channel and throat clogging

Isogeometric cohesive zone model for thin shell delamination analysis based on Kirchhoff-Love shell model

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Frontiers of Structural and Civil Engineering 2020年第2期14卷 267-279页

作者： Tran Quoc THAI Timon RABCZUK Xiaoying ZHUANG Institute o f Continuum Mechanics Leibniz University of HannoverHannover 30167Germany Division of Computational Mechanics Ton Due Thang UniversityHo Chi Minh CityVietnam Faculty of Civil Engineering Ton Due Thang UniversityHo Chi Minh CityVietnam

We present a cohesive zone model for delamination in thin shells and composite *** isogeometric(IGA)thin shell model is based on Kirchhoff-Love ***-Uniform Rational B-Splines(NURBS)are used to discretize the exact mid-surface of the shell geometry exploiting their C 1-continuity property which avoids rotational degrees of *** fracture process zone is modeled by interface elements with a cohesive *** numerical examples are presented to test and validate the proposed formulation in predicting the delamination behavior of composite structures.

关键词： cohesive zone model IGA Kirchhoff-Love model thin shell analysis delamination

Entangled-photons generation with quantum dots

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Chinese Physics B 2018年第2期27卷 140-153页

作者：李远丁飞 Oliver G Schmidt Institute for Integrative Nanosciences IFW Dresden HelmholtzstraBe 20. 01069 Dresden. Germany Integrative for Solid State Physics. leibniz university of Hunnover. AppelstBe 2.30 167 Hannovel Germany

Entanglement between particles is a crucial resource in quantum information processing, an important example of which is the exploitation of entangled photons in quantum communication protocols. Among the different available sources of entangled photons, semiconductor quantum dots （QDs） excel owing to their deterministic emission properties, potential for electrical injections, and direct compatibility with semiconductor manufacturing techniques. Despite the great promises, QD-based sources at＇e far from being ideal. In particular, such sources present several critical issues, which require the overcoming of challenges pertaining to spectral tunability, entanglement fidelity, photon indistinguishability and brightness. In this article, we will discuss the potential solutions to these problems and review the recent progress in the field.

关键词： quantum information entangled-photon source quantum dots

A computational fluid dynamics model for wind simulation:model implementation and experimental validation

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2012年第4期13卷 274-283页

作者： Zhuo-dong ZHANG Ralf WIELAND Matthias REICHE Roger FUNK Carsten HOFFMANN Yong LI Michael SOMMER Institute of Soil Landscape Research Leibniz-Centre for Agricultural Landscape Research(ZALF)Muencheberg 15374Germany Institute of Landscape System Analysis Leibniz-Centre for Agricultural Landscape Research(ZALF)Muencheberg 15374Germany Institute of Agricultural Environment and Sustainable Development Chinese Academy of Agricultural Sciences(CAAS)Beijing 100081China Institute of Earth and Environmental Science University of PotsdamPotsdam 14476Germany

To provide physically based wind modelling for wind erosion research at regional scale, a 3D computational fluid dynamics (CFD) wind model was developed. The model was programmed in C language based on the Navier-Stokes equations, and it is freely available as open source. Integrated with the spatial analysis and modelling tool (SAMT), the wind model has convenient input preparation and powerful output visualization. To validate the wind model, a series of experiments was con- ducted in a wind tunnel. A blocking inflow experiment was designed to test the performance of the model on simulation of basic fluid processes. A round obstacle experiment was designed to check if the model could simulate the influences of the obstacle on wind field. Results show that measured and simulated wind fields have high correlations, and the wind model can simulate both the basic processes of the wind and the influences of the obstacle on the wind field. These results show the high reliability of the wind model. A digital elevation model (DEM) of an area (3800 m long and 1700 m wide) in the Xilingele grassland in Inner Mongolia (autonomous region, China) was applied to the model, and a 3D wind field has been successfully generated. The clear imple- mentation of the model and the adequate validation by wind tunnel experiments laid a solid foundation for the prediction and assessment of wind erosion at regional scale.

关键词： Wind model Computational fluid dynamics (CFD) Wind erosion Wind tunnel experiments Spatial analysis andmodelling tool (SAMT) Open source

Improvements in Inversion of Magnetic Resonance Exploration-Water Content, Decay Time, and Resistivity

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Journal of China university of Geosciences 2009年第3期20卷 592-605页

作者： Ugur Yaramanci Mike Müller-Petke leibniz Institute of Applied Geophysics Stilleweg 2 Hannover D-30655 Germany Berlin university of Technology Ackerstrasse 71-76 Berlin D-13355 Germany

In this review article, we present recent developments and improvements in magnetic resonance sounding （MRS）, a newly established geophysical exploration method that provides unique information about hydrogeophysical properties due to its direct sensitivity to hydrogen protons and proton dynamics. Starting with the most sophisticated and complete MRS formulation, we give a detailed view on how to solve the equation, i.e., inverting exactly for all model parameters： water content, decay time, and resistivity. Giving a short review of general inversion schemes used in geophysics, the special properties of MRS inversion are evaluated and the development of MRS inversion over recent years is shown. We present the extension of MRS to magnetic resonance tomography （MRT）, i.e., the extension to two-dimensional investigations and appropriate inversions. Finally, we address restrictions, limitations, and inconsistencies as well as future developments.

关键词： magnetic resonance sounding (MRS) magnetic resonance tomography (MRT) inversion modeling water content decay time resistivity.

TIME DOMAIN BOUNDARY ELEMENT METHODS FOR THE NEUMANN PROBLEM： ERROR ESTIMATES AND ACOUSTIC PROBLEMS

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Journal of Computational Mathematics 2018年第1期36卷 70-89页

作者： Heiko Gimperlein Ceyhun Ozdemir Ernst P. Stephan Maxwell Institute for Mathematical Sciences and Department of Mathematics Heriot-Watt University Edinburgh EH14 4AS UK andInstitute for Mathematics University of Paderborn 33098 Paderborn Germany Institute of Applied Mathematics Leibniz University Hannover 30167 Hannover Germany

We investigate time domain boundary element methods for the wave equation in R3, with a view towards sound emission problems in computational acoustics. The Neumann problem is reduced to a time dependent integral equation for the hypersingular operator, and we present a priori and a posteriori error estimates for conforming Galerkin approxima- tions in the more general case of a screen. Numerical experiments validate the convergence of our boundary element scheme and compare it with the numerical approximations ob- tained from an integral equation of the second kind. Computations in a half-space illustrate the influence of the reflection properties of a flat street.

关键词： Time domain boundary element method Wave equation Neumann problem,Error estimates Sound radiation.

A Setup for a Scenario-Driven Water Balance at Landscape Scale—Assessment with AKWA-M~-Embedded in a Model Framework for Land-Use Planning’s Decision Support in Mountainous Southwest China

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Journal of Earth Science 2010年第6期21卷 974-978页

作者： Andreas Wahren Karin Berkhoff Albrecht Münch Sylvia Herrmann Karl-Heinz Feger Insitute of Soil Science and Site Ecology Technische Universitt Dresden Dr. Dittrich & Partner Hydro-Consult GmbH Institute of Environmental Planning Leibniz University Hannover

Land-cover changes cause a loss of natural vegetation in many parts of the world. In the Xishuangbanna （西双版纳） district （Yunnan （云南） Province）, rubber plantations replace tropical rainforests covering already an area of about 10% of the study area （2007）. There, land-use allocation is mostly driven by economic considerations. Thus, local planning authorities need decision support for land-use planning issues, which integrate socio-economic and ecological aspects. Within the NabanFrame, an agro-economic, ecological and social model was applied, which, altogether, interacted with a land allocation model via defined interfaces. Effects on the water cycle, ecological conditions as well as socio-economic should be considered by integrating the spatially distributed rainfali-runoff and water balance model AKWA-M in the model setup.

关键词： land-use water balance model rubber integrated land-use planning land-use prognosis.

Do credit constraints affect households'economic vulnerability?Empirical evidence from rural China

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Journal of Integrative Agriculture 2021年第9期20卷 2552-2568页

作者： PENG Yan-ling Yanjun REN LI Hou-jian College of Economics Sichuan Agricultural UniversityChengdu 611130P.R.China Department of Agricultural Markets Leibniz Institute of Agricultural Development in Transition EconomiesHalle(Saale)06120Germany

Poverty alleviation is still one of the major challenges in developing countries,especially in transitional economy like *** the perspective of anti-poverty,this paper examines the impact of formal credit constraints(FCCs)and informal credit constraints(IFCCs)on economic vulnerability(EV)using the data from the China Household Income Project(CHIP)survey for 2013(CHIPs 2013)of rural *** potential endogeneity problem of credit constraints(CCs)is addressed by applying the control function approach within an ordered probit *** results show that both FCCs and IFCCs have a robust positive and significant impact on the EV of rural households and that the impact of FCCs is greater than that of *** identify the potential mechanisms through which CCs affect EV,the seemingly unrelated regressions are used and the potential intercorrelation among these mechanisms is *** find that the impact of CCs on EV is partly mediated by health,trust,per capita financial assets and per capita income,whereby health and per capita income contribute to most of the total indirect ***,policies focus on supply-side and demand-side to improve credit accessibility could reduce rural households'EV,especially through its positive effect on health and per capita income.

关键词： credit constraints economic vulnerability causal mediation mechanisms rural China

Evolution of particle number size distribution in an urban atmosphere during episodes of heavy pollution and new particle formation

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Science China Earth Sciences 2011年第11期54卷 1772-1778页

作者： WU ZhiJun, HU Min YUE DingLi Birgit WEHNER Alfred WIEDENSOHLER State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing 100871 China leibniz-lnstitutefor Tropospheric Research 04318 Leipzig Germany

This study discusses the evolution of particle number size distribution during episodes of heavy pollution and new particle formation in the urban atmosphere of Beijing to quantify the effects of dynamic processes (coagulation and condensation) on the particle number size *** a heavy-pollution event,an extremely low number concentration of 3-10 nm particles (on average 46 cm-3) was *** is because nucleation-mode particles were easily removed by strong coagulational scavenging of larger particles under this *** addition,a large condensation sink (on average 0.13 s-1) restrained nucleation,which is one of the major sources of nucleation-mode ***,during a new-particle formation event,the small condensation sink (0.01 s-1) of precursor facilitated *** the same time,preexisting particles had little ability to scavenge newly formed particles (around 1 nm) and allowed them to grow to a detectable size (larger than 3 nm currently).We suggest that the effects of dynamic processes (coagulation and condensation) on particle size distribution should be stressed under some extreme conditions of the relatively polluted urban atmosphere in addition to traffic and meteorological factors.

关键词： particle number size distribution new particle formation coagulation and condensation sinks