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Litter Dynamics of Three subalpine Forests in Western sichuan

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Pedosphere 2005年第5期15卷 111-117页

作者： s. KELLOMki University of Joensuu P. O. Box 111 Faculty of Forestry FIN-80101 (Finland)

Litter production, components and dynamics were investigated and forest floor litter was quantified throughout awhole year in three subalpine forests, dominated by tree species of spruce (sF), fir (FF) and birch (BF), in Westernsichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in thethree forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to thetotal litterfall was significantly (P s or moss. Regardlessof the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October,with smaller peaks occurring in February for sF and FF, and May for BF. The analysis indicated that tree species,stand density, leaf area index (LAI), stand basal area and stand age were the key factors determining litter *** tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter componentsand dynamics.

关键词： litter dynamics litter stock litter production subalpine forests

Effect of drawing speed on microstructure distribution and drawability in twinning-induced plasticity steel during wire drawing

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Journal of Iron and steel Research International 2020年第5期27卷 577-587页

作者： Joong-ki Hwang school of Mechanical Engineering Tongmyong UniversityBusan 48520Republic of Korea

The effect of drawing speed on temperature rise and microstructure distribution in twinning-induced plasticity(TWIP)steel during wire drawing has been investigated to improve drawability for wire rod *** wire drawing process is performed at room temperature,heat is generated due to the plastic deformation and friction at the wire-die *** steel wires subjected to the low drawing speed(LD)of 0.5 m/min and the high drawing speed(HD)of 5.0 m/min were analyzed using the numerical simulation and electron backscatter diffraction ***,the specimens subjected to the HD had a higher drawability by about 18%compared to the LD,which is totally different from the general behavior of plain carbon pearlitic *** LD wire had uniform temperature distribution along the radial direction during wire *** contrast,the HD wire had a temperature gradient along the radial direction due to the higher frictional effect at surface:the minimum temperature of 58℃ at center area and the maximum temperature of 143 C at surface *** higher stacking fault energy of HD wire at the surface area due to the high temperature rise retarded twinning rate,resulting in the prevention of fast exhaustion in ductility in comparison with the LD wires since the earlier depletion of twins at surface area is known as the main reason for the fracture of TWIP steel during wire ***,HD process delayed the fracture strain of wire and increased the uniformity of microstructure and mechanical properties along the radial direction.

关键词： Twinning-induced plasticity steel Wire drawing Deformation twin Drawing speed Temperature rise

strain hardening rate dependency of deformation shape,strain distribution,and contact pressure during wire flat rolling

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Journal of Iron and steel Research International 2023年第3期30卷 475-486页

作者： Joong-ki Hwang school of Mechatronics Engineering Korea University of Technology and EducationCheonan 31253Republic of Korea

The effect of the strain hardening exponent(n)of a material on the changes in shape,strain inhomogeneity,and contact pressure was investigated during wire flat rolling to understand its effect on the deformation behavior of a flat-rolled wire and to determine the optimal working conditions with *** deformation behaviors of wires with various n values were systematically compared using finite element *** shape of the deformed wire was found to depend on the n value of the *** the contact width and lateral spreading of the wire decrease with increasing n,resulting in a large reduction in area with the n *** strain homogeneity of the wire increases with the n value of the *** improvement in the strain homogeneity with the n value is attributable to two factors:a lower strain concentration in the central region and a higher overall elongation as n *** addition,the average effective strain of the wire cross section decreases with the n value of a material during wire flat *** contact pressure distribution on the surface of the wire differs significantly depending on the n *** materials with a low n value,the contact pressure exhibits a higher value at the entry and edge zones of the contact *** contrast,materials with high n values exhibit a higher contact pressure at the exit *** behavior can be explained by the strain hardening behavior of the material during wire flat rolling.

关键词： strain hardening exponent Wire flat rolling shape change strain inhomogeneity Contact pressure

Numerical studies on swirling of internal fire whirls with experimental justifications

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Building simulation 2021年第5期14卷 1499-1509页

作者： Zheming Gao s.s.Li Y.Gao H.Y.Hung Wan-ki Chow Midea Residential Air Conditioner Division FoshanGuangdongChina College of Aerospace and Civil Engineering Harbin Engineering UniversityHarbinHeilongjiangChina Department of Building services Engineering The Hong Kong Polytechnic UniversityHunghomKowloonHong KongChina

Numerical studies on internal fire whirls(IFW)generated in a vertical shaft model with a single corner gap were reported in this *** generation of IFW,burning rate of fuel and temperature were studied experimentally *** simulations on medium-scale IFW were carried out using a fully-coupled large eddy simulation incorporating subgrid scale turbulence and a fire source with heat release rates compiled from experimental *** transient flame shape was studied and then simulated numerically by using *** dynamic phenomena of generation and development of IFW were simulated and then compared with experimental *** predicted results were validated by comparing with experimental data,which demonstrated that an IFW can be simulated by Computational Fluid *** results for flame surface,temperature,and flame length agreed well with the experimental *** IFW flame region and intermittent region were longer than those for an ordinary pool *** modified empirical formula for centerline temperature was *** of vertical and tangential velocity in axial and radial directions were also *** vortex core radius was found to be determined by the fuel bed *** field was not measured extensively due to resources *** measured temperature distribution with predictions is acceptable because temperature is related to the heat release rate,air flow and pressure gradient.

关键词： internal fire whirl large eddy simulation vertical structure flame surface

Developing a geospatial web-GIs system for landscape and urban planning

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International Journal of Digital Earth 2013年第6期6卷 580-588页

作者： Junghoon ki Department of Public Administration Myongji UniversitySeoulKorea

This study discusses a geographical information system(GIs)for operating a local government’s landscape and urban planning activities via a *** this web-GIs system will help build a more realistic landscape and urban planning model that includes citizen participation and city *** approach is applicable to ubiquitous city(u-city)development based on geospatial web and its related *** approach presented is built on six selected elements of a u-city *** outcome of the study includes sustainable analysis,environmental planning,urban planning,and city market*** outcome is applicable to cities that are planning to adopt the u-city system or advanced telecommunication or planning tools into their urban frameworks.

关键词： geospatial data integration virtual reality 3D modeling ubiquitous city sustainable development

Indoor INs/UWB-based Human Localization With Missing Data Utilizing Predictive UFIR Filtering

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IEEE/CAA Journal of Automatica sinica 2019年第4期6卷 952-960页

作者： Yuan Xu Choon ki Ahn Yuriy s. shmaliy Xiyuan Chen Lili Bu IEEE the school of Electrical Engineering University of JinanJinan 250022China the school of Electrical Engineering Korea UniversitySeoul 08241Republic of Korea the Department of Electronics Engineering Universidad de GuanajuatoSalamanca 36885Mexico the school of Instrument science and Engineering Southeast University

A combined algorithm for the loosely fused ultra wide band(UWB)and inertial navigation system(INs)-based measurements is designed under the indoor human navigation conditions with missing *** scheme proposed fuses the INs-and UWB-derived positions via a data fusion *** the UWB signal is prone to drift in indoor environments and its outage highly affects the integrated scheme reliability,we also consider the missing data problem in UWB *** overcome this problem,the loosely-coupled INs/UWB-integrated scheme is augmented with a prediction option based on the predictive unbiased finite impulse response(UFIR)fusion *** show experimentally that,the standard UFIR fusion filter has higher robustness than the Kalman *** is also shown that the predictive UFIR fusion filter is able to produce an acceptable navigation accuracy under temporary missing UWB-data.

关键词： Indoor human navigation INs/UWB model prediction unbiased FIR filter

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Effect of reduction in area per pass on strain distribution and microstructure during caliber rolling in twinning-induced plasticity steel

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Journal of Iron and steel Research International 2020年第1期27卷 62-74页

作者： Joong-ki Hwang sung Jin kim school of Mechanical Engineering Tongmyong UniversityBusan 48520Republic of Korea Department of Advanced Materials Engineering Sunchon National UniversitySuncheon 57922Republic of Korea

The effects of reduction in area(RA)per pass during caliber rolling on microstructure and strain distribution of twinninginduced plasticity steel have been investigated to find solutions to make a more homogeneous material along the radial direction for wire rod *** steel wires subjected to an average RA per pass of 2.5%(skin pass caliber rolling)and 10.0%(conventional caliber rolling)were *** skin pass caliber-rolled wire was characterized as a duplex fiber texture of majorand minor.and the textures were almost same at/between center and surface area,which is totally different from those of conventional caliber rolling and wire *** skin pass caliber rolling led to more homogeneous microstructure and mechanical properties along the radial direction in comparison with the conventional caliber rolling and wire drawing due to the more homogeneous Hall-Petch hardening,dislocation hardening,and texture behavior with area,resulting in higher formability.

关键词： Twinning-induced plasticity steel Caliber rolling Deformation twin Reduction in area skin pass

Corrosion characteristics of steel in seawater containing various chloride concentrations generated by electrochemical method

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中国有色金属学会会刊：英文版 2009年第B09期19卷 50-55页

作者： seong-Jong kiM seok-ki JANG Division of Marine Engineering Mokpo Maritime University

The electro-clean system (ECs), a ballast water management system that eliminates harmful aquatic organisms in ship ballast water via electrochemically produced chloride, was developed. The current density for potentiostatic experiments subjected to seawater with an applied potential (-0.1 V) at various TRC concentrations (2×10-6, 6×10-6, 10×10-6, and 15×10-6) have similar results. The current density at -0.1 V has the highest value compared with that at -0.7 V and -0.4 V. For all concentrations, the current density increases with increasing applied potential.

关键词：含氯化物电化学方法腐蚀特性浓度海水船舶压载水钢铁电流密度

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H∞ stability conditions for delayed neural networks with external disturbances and norm-bounded uncertainties:Delay independent and dependent criteria

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science China(Information sciences) 2011年第8期54卷 1691-1701页

作者： Choon ki AHN Department of Automotive Engineering seoul National University of science & Technology

In this paper,we propose new delay independent and dependent H ∞ stability conditions for delayed neural networks with external disturbances and norm-bounded *** conditions are presented to not only guarantee the asymptotical stability but also reduce the effect of external disturbance to an Hnorm constraint. The proposed conditions are represented by linear matrix inequalities （LMIs）.Optimal Hnorm bounds are obtained easily by solving convex problems in terms of *** applicability of these conditions is illustrated by numerical examples.

关键词： H_∞ analysis delayed neural networks uncertainty disturbance linear matrix inequality (LMI)