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Science china(Technological Sciences) 2010年第4期53卷 991-999页

作者： ZHAN NaiYan1,2,YANG Mo1 & XU PeiWei2 1 College of Power engineering,University of Shanghai for Science and Technology,Shanghiai 200093,china 2 department of environmental engineering,jilin architectural and civil engineering institute,changchun 130021,china 1. College of Power engineering University of Shanghai for Science and Technology Shanghiai 200093 China2. Department of Environmental Engineering Jilin Architectural and Civil Engineering Institute Changchun 130021 China

Numerical investigation using SIMPLE algorithm with QUICK scheme for natural convection and heat transfer in the enclosure bounded by a solid wall and with heat transfer and radiation coupled in natural convection has been *** various parameters are:Rayleigh number(from 103 to 105),dimensionless conductivity of bounding wall(from 0 to 100),dimensionless wall thickness(from 0 to 0.6) and radiation emissivity of all surfaces(from 0 to 1).The results suggest that flow and heat transfer are influenced by *** is a dominant action on flow and heat *** increase of the thermal conductivity of wall,flow and heat transfer turn *** temperature distribution changes *** the thermal conductivity of wall is over a certain critical number,the increasing trend of flow and heat transfer may *** increase of enclosure wall thickness,flow and heat transfer turn *** the enclosure wall thickness is over a certain critical number,the flow and heat transfer will turn slow.

关键词： conduction natural convection radiation couple numerical simulation

Study on the stability and 3-dimensional character for natural convection in a rectangular cavity heated from below

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Science china(Technological Sciences) 2010年第6期53卷 1647-1654页

作者： ZHAN NaiYan1,2,XU PeiWei1,SUN ShiMei,YANG Mo2 & LIU Jun3 1 Scool of Municipal and environmental engineering,jilin institute of architectural and civil engineering,changchun 130021,china 2 College of Power engineering,University of Shanghai for Science and Technology,Shanghiai 200093,china 3 College of Power engineering,jilin University,changchun 130000,china 1. Scool of Municipal and environmental engineering Jilin Institute of Architectural and Civil Engineering Changchun 130021 China2. College of Power Engineering University of Shanghai for Science and Technology Shanghiai 200093 China3. College of Power Engineering Jilin University Changchun 130000 China

Natural convection of air is numerically simulated in a 3-dimensional rectangular cavity heated from below using SIMPLE algorithm with a QUICK *** results suggest that when all lateral walls are adiabatic,the fluid rolls occur along the long *** the Rayleigh number is smaller,the flow is of 2-dimensional character,and the rolls shapes are *** average Nusselt numbers in the central part of the cavity are *** average Nusselt numbers in the part near by the cavity are *** to the comparison of 3-dimensional results with 2-dimensional results,the flow patterns and heat transfer in the central part of the cavity can be assumed as a 2-dimensional flow,While those in the part near by the cavity can *** increasing Rayleigh number,the flow is 3-dimensional *** 3-dimensional result accords with the experimental *** all lateral walls are adiabatic,the ten rolls occur along the long *** when lateral walls are heated or cooled,the rolls disappear along the long axis and two rolls occur along the short *** rotation direction of the rolls is *** Rayleigh number is over some critical value,flow and heat transfer will be asymmetry,indicating unsteady oscillation *** nonlinear analyses,it is shown that with increasing Rayleigh number,flow and heat transfer will change from steady state to unsteady state through HOPF bifurcation,and transition to chaos will occur through multi-periodical oscillation.

关键词： Critical Raleigh number 3-dimensional character lateral boundaries nonlinear characteristic bifurcation

Synthesis of Polycrystalline Yb:Gd_3Ga_5O_(12) Nanopowders by Homogeneous Precipitation Method

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Journal of Wuhan University of Technology(Materials Science) 2010年第1期25卷 123-126页

作者：黄德馨刘景和 department of Materials Science and engineering Changchun University of Science and Technology department of Materials Science and engineering Jilin Architectural and Civil Engineering Institute

The Ytterbium doped gadolinium gallium garnet [Yb3＋：Gd3Ga5O12, Yb：GGG] precursor powders were synthesized via homogeneous precipitation method using Yb2O3, Ga2O3, Gd2O3 and ammonium bicarbonate [NH4HCO3] as precipitator, and ammonium sulfate [（NH4）2SO4] as additive. The evolution of phase composition and micro-structure of the powders were characterized by TG- DTA, XRD, IR, and TEM. The results indicate that all precursor powders completely transform to Yb：GGG phase by calcining at 900 ℃ for 8 h, the resultant powders are well dispersed and have smaller particle size approximately 80 nm owing to the electrostatic effect.

关键词： Yb:Gd3Ga5O12 polycrystalline homogeneous precipitation nanopowders

A land surface model incorporated with soil freeze/thaw and its application in GAME/Tibet

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Science china Earth Sciences 2006年第12期49卷 1311-1322页

作者： HU Heping1, YE Baisheng2, ZHOU Yuhua3 & TIAN Fuqiang1 1. department of Hydraulic engineering, Tsinghua University, Beijing 100084, china 2. Cold and Arid Regions environmental and engineering Research institute, Chinese Academy of Sciences, Lanzhou 730000, china 3. department of civil engineering, Massachusetts institute of Technology, USA 1. department of Hydraulic engineering Tsinghua University Beijing 100084 China 2. Cold and Arid Regions environmental and engineering Research institute Chinese Academy of Sciences Lanzhou 730000 China 3. department of civil engineering Massachusetts Institute of Technology USA

Land surface process is of great importance in global climate change, moisture and heat exchange in the interface of the earth and atmosphere, human impacts on the environment and eco- system, etc. Soil freeze/thaw plays an important role in cold land surface processes. In this work the diurnal freeze/thaw effects on energy partition in the context of GAME/Tibet are studied. A sophisti- cated land surface model is developed, the particular aspect of which is its physical consideration of soil freeze/thaw and vapor flux. The simultaneous water and heat transfer soil sub-model not only reflects the water flow from unfrozen zone to frozen fringe in freezing/thawing soil, but also demon- strates the change of moisture and temperature field induced by vapor flux from high temperature zone to low temperature zone, which makes the model applicable for various circumstances. The modified Picard numerical method is employed to help with the water balance and convergence of the numerical scheme. Finally, the model is applied to analyze the diurnal energy and water cycle char- acteristics over the Tibetan Plateau using the Game/Tibet datasets observed in May and July of 1998. Heat and energy transfer simulation shows that: (i) There exists a negative feedback mechanism between soil freeze/thaw and soil temperature/ground heat flux; (ii) during freezing period all three heat fluxes do not vary apparently, in spite of the fact that the negative soil temperature is higher than that not considering soil freeze; (iii) during thawing period, ground heat flux increases, and sensible heat flux decreases, but latent heat flux does not change much; and (iv) during freezing period, soil temperature decreases, though ground heat flux increases.

关键词： land surface model,soil freeze/thaw,GAME/Tibet,simultaneous liquid,vapor and heat transfer.

THE TRANSFORMED NONPARAMETRIC FLOOD FREQUENCY ANALYSIS

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Journal of Computational Mathematics 1994年第4期12卷 330-338页

作者： Kaz Adamowski(department of civil engineering University of Ottawa, Ottawa, Canada)Wojciech Feluch(institute of environmental engineering , Technical University of Warsaw, Warsaw, Poland) UNIV OTTAWA DEPT CIVIL ENGNOTTAWA K1N 6N5ONTARIOCANADA WARSAW UNIV TECHNOL INST ENVIRONM ENGNPL-00661 WARSAWPOLAND

The nonparametric kernel estimation of probability density function (PDF) pro-vides a uniform and accurate estimate of flood frequency-magnitude ***, the kernel estimate has the disadvantage that the smoothing factor h is estimate empirically and is not locally adjusted, thus possibly resulting in deteri oration of density estimate when PDF is not smooth and is heavy-tailed. Such a problem can be alleviate by estimating the density of a transformed random vari able, and then taking the inverse transform. A new and efficient circular transform is proposed and investigated in this paper

关键词： TRT Res THE TRANSFORMED NONPARAMETRIC FLOOD FREQUENCY ANALYSIS

Nitrogen removal in sequencing batch reactor

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Journal of environmental Sciences 1994年第2期6卷 164-172页

作者： Wang Fuzhen Peng Yongzhen Yu Erjie Li Baikun(Harbin architectural and civil engineering institute, Harbin 150001, china)Chen Aifeng(HeilonUiang environmental Monitory Center, Harbin 150056, china)

This article introduces biodenittification rule of several operation in SBR system. Theresults show that sequencing aeration in SBR meets the needs of oxic and anoxic conditions ofbio-denitrification, and it is a promising bio-denitrification technique. It is the first discover thatduring the treatment of brewery wastewater, when the brewery wastewater is added in the activatedsludge, its denitrinfication rate is faster than methyl alcohol added. This experimental result has greatsignificance. It is suggested that adding original brewery wastewater shall be first considered inbio-denitrification of several kinds of wastewater. Altenlative operation of aeration and mixation,namely nitnfication and denitnfication, has high denitnfication efficiency.

关键词： SBR aeration, nitrification denitrification

Self-centering seismic retrofit scheme for reinforced concrete frame structures:SDOF system study

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Earthquake engineering and engineering Vibration 2010年第2期9卷 271-283页

作者： Yunfeng Zhang and Xiaobin Hu department of civil and environmental engineering,University of Maryland,College Park,MD 20742,USA department of civil and environmental engineering University of Maryland College Park 20742 USA

This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and minimal residual deformation. For comparison purpose,an alternate seismic retrofit scheme that uses a bilinear-hysteresis retrofit system such as buckling-restrained braces (BRB) is also considered in this paper. The parametric study was carried out in a single-degree-of-freedom (SDOF) system framework since a multi-story building structure may be idealized as an equivalent SDOF system and investigation of the performance of this equivalent SDOF system can provide insight into the seismic response of the multi-story building. A peak-oriented hysteresis model which can consider the strength and stiffness degradation is used to describe the hysteretic behavior of RC structures. The parametric study involves two key parameters -the strength ratio and elastic stiffness ratio between the seismic retrofit system and the original RC frame. An ensemble of 172 earthquake ground motion records scaled to the design basis earthquake in California with a probability of exceedance of 10% in 50 years was constructed for the simulation-based parametric study. The effectiveness of the two seismic retrofit schemes considered in this study is evaluated in terms of peak displacement ratio,peak acceleration ratio,energy dissipation demand ratio and residual displacement ratio between the SDOF systems with and without retrofit. It is found from this parametric study that RC structures retrofitted with the self-centering retrofit scheme (SCRS) can achieve a seismic performance level comparable to the bilinear-hysteresis retrofit scheme (BHRS) in terms of peak displacement and energy dissipation demand ratio while having negligible residual displacement after earthquake.

关键词： earthquake reinforced concrete frame structure nonlinear analysis SDOF system seismic retrofit self-centering

Damage and progressive failure of concrete structures using non-local peridynamic modeling

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Science china(Technological Sciences) 2011年第3期54卷 591-596页

作者： HUANG Dan1,2, ZHANG Qing1,2 & QIAO PiZhong1,3 1 State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering, Hohai University, Nanjing 210098, china 2 department of engineering Mechanics, Hohai University, Nanjing 210098, china 3 department of civil and environmental engineering, Washington State University, Pullman, WA 99164-2910, USA 1. State Key Laboratory of Hydrology-Water Resources and Hydraulic engineering Hohai University Nanjing 210098 China2. Department of Engineering Mechanics Hohai University Nanjing 210098 China3. Department of Civil and Environmental Engineering Washington State University Pullman WA 99164-2910 USA

Peridynamics (PD), a recently developed theory of solid mechanics, which employs a non-local model of force interaction and makes use of integral formulation rather than the spatial partial differential equations used in the classical continuum mechanics theory, has shown effectiveness and promise in solving discontinuous problems at both macro and micro scales. In this paper, the peridynamics theory is used to analyze damage and progressive failure of concrete structures. A non-local peridynamic model for a rectangular concrete plate is developed, and a central pairwise force function is introduced to describe the interior interactions between particles within some definite distance. Damage initiation, evolution and crack propagation in the concrete model subject to in-plane uni-axial tension, in-plane uni-axial compression and out-of-plane impact load are investigated respectively. The numerical results show that discontinuities appear and grow spontaneously as part of the solution to the peridynamic equations of motion, and no special failure criteria or re-meshing techniques are required, which proves the potential of peridynamic modeling as a promising technique for analyzing the progressive failure of concrete materials and structures.

关键词： concrete damage progressive failure peridynamic model discontinuities

Chuetsu earthquake damages in Niigata County of Japan

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Progress in Natural Science:Materials International 2007年第10期17卷 1255-1259页

作者： Li Hongnan1, Zhao Yangang2 and Wang Guoxin1(1. State Key Laboratory of Coastal and Offshore engineering, Dalian University of Technology, Dalian 116024, china 2. department of civil and architectural engineering, Nagoya institute of Technology, Nagoya 466-8555, Japan) State Key Laboratory of Coastal and Offshore engineering Dalian University of Technology Dalian 116024 China department of civil and architectural engineering Nagoya Institute of Technology Nagoya 466-8555 Japan

An Earthquake ML=6.8 occurred on October 23, 2004 in Chuetsu area of Niigata County in Japan, which caused 40 people dead, more than 4500 people injured and 1000000 people homeless; nearly 140000 buildings were damaged or collapsed. The estated total loss of this earthquake was about 3000 billions Yen. In this paper, we investigate the Chuetsu earthquake damage from different aspects, including the seismic outline, seismicity, intensity distribution, wave feature, damage analyses, and economic losses. Finally, experiences and lessons from the earthquake damage are given. The content in this paper may be a reference for structural seismic design and code modification.

关键词： Chuetsu earthquake seismic damage Niigata province in Japan.

Bipolar charged aerosol agglomeration and collection by a two-zone agglomerator

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Journal of environmental Sciences 2001年第3期13卷 276-279页

作者： XIANG Xiao dong 1, CHEN Bao zhi 1, COLBECK I 2 (1. School of Resource and civil engineering, Northeastern University, Shenyang 110006, china. 2. institute for environmental Research, department of Biological and Chemical Sciences, University of Es School of Resource and civil engineering Northeastern University Shenyang 110006 China.

In older to collect fine particles more efficiently, a new-type electrostatic agglomerator with two zones was developed. The distinguishing feature of this electrostatic agglomerator is that the particles are bipolarly charged and coagulated in the same alternating electric field simultaneously. The silica flour with 2 fun mass median diameter and the smoke from burning wood powder were used as test aerosol. The comparison experimental results have shown that when the mean electric field is 4 kV/cm the collection efficiency of the new electrostatic agglomerator was 98.2% for silica flour and 67.4% for wood powder smoke, Under the same experimental condition. the collection efficiency of the electrostatic agglomerator with three zones was 97.4% for collecting silica flour and the collection efficiency of the electrostatic precipitator was 56.3% for wood powder smoke.

关键词： charged particle agglomeration alternating electric field electrostatic agglomerator (EA) electrostatic precipitator (ESP) collection efficiency