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Journal of Hydrodynamics 2004年第6期16卷 708-715页

作者： RENAn-lu CHENWen-qu LIGuang-wang DepartmentofMechanics ZhejiangUniversityHangzhou310027China

A numerical study was conducted for the vortex-induced vibrations of anelastic circular cylinder at low Reynolds numbers. An Arbitrary Lagrangian-Eulerian (ALE) method wasemployed to deal with the fluid-structure interaction with an H-O type of non-staggered gridsincorporating the domain decomposition method (DDM), which could save the computational CPU time dueto re-meshing. The computational domain was divided into nine sub-domains including one ALEsub-domain and eight Eulerian sub-domains. The convection term and dissipation term in the N-Sequations were discretized using the third-order upwind compact scheme and the fourth-order centralcompact scheme, respectively. The motion of the cylinder was modeled by a spring-damper-mass systemand solved using the Runge-Kutta method. By simulating the non-linear fluid-structure interaction,the ''lock-in'', ''beating'' and ''phase switch'' phenomena were successfully captured, and the resultsagree with experimental data Furthermore, the vortex structure, the unsteady lift and drag on thecylinder, and the cylinder displacement at various natural frequency of the cylinder for Re = 200were discussed in detail, by which a jump transition of the wake structure was captured.

关键词： arbitrary lagragian-eulerian (ALE) method vortex-induced vibrations domaindecomposition Method (DDM) flow around a circular cylinder compact schemes

NUMERICAL SIMULATION OF FLOW-INDUCED VIBRATION ON TWO CIRCULAR CYLINDERS IN TANDEM ARRANGEMENT

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Journal of Hydrodynamics 2005年第6期17卷 660-666页

作者： DENG Jian REN An-lu CHEN Wen-qu Department of Mechanics Zhejiang University Hangzhou 310027 China

Flow-induced vibration of two circular cylinders in tandem arrangement elastically mounted with a massspring-damping system was studied by solving the primitive variable Navier Stokes equations incorporating the Arbitrary Lagrangian-Eulerian （ALE） method. The convection term and dissipation term were discretized using the third-order upwind compact scheme and the fourth-order central compact scheme, respectively. The typical spacing between the cylinders is 4 diameters, which is close to the critical value. The dynamic response of the vibrations on two cylinders with two-degreeof-freedom motion is different from that of an isolated cylin der, and also different from that of a cylinder vibrating in the wake of a fixed upstream one. Different flow patterns were found in the wake, and proved to be relevant to the discontinuities observed in the response of the oscillatory cylinders.

关键词： flow by two cylinders flow-induced vibration high-order compact scheme dynamic response

Spatio-temporal evolution of ecologically-sustainable land use in China's Loess Plateau and detection of its influencing factors

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Journal of Mountain Science 2019年第5期16卷 1065-1074页

作者： qu lu-lu LIU Yan-sui CHEN Zong-feng Faculty of Geographical Science Beijing Normal University Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

Ecological land(Eco-land) is a basic resource for human beings to survive, and eco-land use is a strategy, a way to manage the land resource. So, ecologically-sustainable land use is essential for human beings to survive. This paper investigates the spatiotemporal characteristics and mechanisms of urban-rural eco-land using a new and innovative integration way based on eco-land change data in China's Loess Plateau(LP) prefecture level cities and explores factors of eco-land change. The spatial difference characteristic of eco-land among different level cities in the LP is that: small cities > big cities > middle cities. From 2009 to 2016, the eco-land in the LP from the perspective of urban-rural areas has changed significantly. Significant differences of urban-rural eco-land were identified among various urban growth types, and all the cities in the LP were further classified into four types based on eco-land change trend, with type A and B cities identified as the vital zone and major zone. Taking the eco-fragile region Loess Plateau(LP) as an example, our results demonstrated that the migrants to cities in LP could relieve ecological pressures and promote restoration of ecological vegetation. We have demonstrated that urbanization and the influence of government policy can be discerned through the quantification of the spatial-temporal change of eco-land and suggest that combining both urban and rural eco-land can support more effective land use decisions and provide theoretical basis for the practical application of urban planning, policy-making and sustainable development. What's more, governments should strive to population mobility and restore vegetation to sustain this fragile ecological environment.

关键词： Ecologically-sustainable land use Spatio-temporal evolution influencing factor Population migration Loess Plateau

Liquid-Solid Phase Transition in Sodium Dodecyl Sulfate Aqueous Solutions by Acoustic Nonlinearity Parameter B/A

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Chinese Physics Letters 1996年第5期13卷 366-369页

作者： lu Zhi-qu GONG Xiu-fen LIU Jie-hui State Key Laboratory of Modern Acoustics Institute of AcousticsNanjing UniversityNanjing 210093

The paper reports the study of liquid-solid phase transition in sodium dodecyl sulfate(SDS)aqueous solution by using acoustic nonlinearity parameter B/*** was found that the point of inflexion occurred in the B/A-T curve just at the liquid-solid phase transition point of SDS aqueous *** result indicates that the nonlinearity parameter B/A can perfectly display the *** phase transition of SDS solution and may develop a new B/A method for determining the phase transition point of fluid.

关键词： solution. nonlinearity transition

X-ray Spectroscopy of Dips of Cir X-1

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Chinese Journal of Astronomy and Astrophysics 2007年第5期7卷 693-704页

作者： Ya-Juan Lei Fang-Jun lu Jin-lu qu Li-Ming Song Cheng-Min Zhang Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

We present X-ray spectral analyses of the low-mass X-ray binary Cir X-1 during X-ray dips, using the Rossi X-ray Timing Explorer （RXTE） data. Each dip was divided into several segments, and the spectrum of each segment was fitted with a three-component blackbody model, in which the first two components are affected by partial covering and the third one is unaffected. A Gaussian emission line is also included in the spectral model to represent the Fe Kα line at - 6.4 keV. The fitted temperatures of the two partially covered components are about 2 keV and 1 keV, while the uncovered component has a temperature of -0.5-0.6 keV. The equivalent blackbody emission radius of the hottest component is the smallest and that of the coolest component is the largest. During the dips the fluxes of the two hot components are linearly correlated, while that of the third component does not show any significant variation. The Fe line flux remains constant, within the errors, during the short dips. However, during the long dips the line flux varies significantly and is positively correlated with the fluxes of the two hot components. These results suggest; （1） that the temperature of the X-ray emitting region decreases with radius, （2） that the Fe Kα line emitting region is close to the hot continuum emitting region, and （3） that the size of the Fe line emitting region is larger than that of the obscuring matter causing the short dips but smaller than the region of that causing the long dips.

关键词： stars individual (Circinus X-1) -- stars neutron -- X-rays stars

Effects of eggshell addition on calcium-deficient acid soils contaminated with heavy metals

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Frontiers of Environmental Science & Engineering 2018年第3期12卷 69-78页

作者： Weiqi luo Yanping Ji lu qu Zhi Dang Yingying Xie Chengfang Yang Xueqin Tao Jianmin Zhou Guining lu School of Environment and Energy South China University of Technology Guangzhou 510006 China The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of Education Guangzhou 510006 China School of Environmental Science and Engineering Zhongkai University of Agriculture and Engineering Guangzhou 510225 China South China Institute of Environmental Sciences Ministry of Environmental Protection Guangzhou 510655 China Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal Guangzhou 510006 China

In this study, effects of water conditions （flooded, wet, or dry） and eggshell dosages （0, 0.1, 1.0, and 10.0 g/kg soil, respectively） on pH variation, content of unavailable state of heavy metals, form of heavy metals, and available nutritious element calcium （Ca） in acid soils contaminated with heavy metals were investigated, respectively. The soil samples were continuously cultivated indoors and analyzed by toxicity characteristic leaching procedure and community bureau of reference （BCR） sequential extraction procedure. The results showed that the addition of eggshell could effectively improve the pH of acid soil and increase it to neutral level. Moreover, the contents of unavailable state of heavy metals Cu, Zn, and Cd increased significantly. Furthermore, when the soil was cultivated under the flooded condition with 1.0 g/kg eggshell, the unavailable state ofCu, Zn, and Cd increased the most, and these heavy metals were transformed into residual state. On the other hand, the amount of available state of Ca increased to 432.19 from 73.34 mg/kg with the addition of 1.0 g/kg eggshell, which indicated that the addition of eggshell dramatically improved the available state of Ca. Therefore, eggshell could ameliorate the soil environment as it led to the decrease of available heavy metals and improvement of fertilization effectively. In a word, this study indicates that the addition of eggshell would be a new potential method for remediation of acid field soils contaminated with heavy metals.

关键词： Heavy metals Eggshell Acid soil remediation BCR sequential extraction

Experimental study on total dissolved gas supersaturation in water

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Water Science and Engineering 2011年第4期4卷 396-404页

作者： lu qu Ran LI Jia LI Ke-feng LI Lin WANG Zhejiang Institute of Hydraulics and Estuary Hangzhou 310020 P. R. China State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 P. R. China

More and more high dams have been constructed and operated in China. The total dissolved gas （TDG） supersaturation caused by dam discharge leads to gas bubble disease or even death of fish, Through a series of experiments, the conditions and requirements of supersaturated TDG generation were examined in this study. The results show that pressure （water depth）, aeration, and bubble dissolution time are required for supersaturated TDG generation, and the air-water contact area and turbulence intensity are the main factors that affect the generation rate of supersaturated TDG. The TDG supersaturation levels can be reduced by discharging water to shallow shoals downstream of the dam or using negative pressure pipelines. Furthermore, the TDG supersaturation levels in stilling basins have no direct relationship with those in reservoirs. These results are of great importance for further research on the prediction of supersaturated TDG generation caused by dam discharge and aquatic protection.

关键词： total dissolved gas supersaturation dissolved gas in water experimental study dam discharge

Demonstration of Inverse Scattering Transform for DNLS Equation

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Communications in Theoretical Physics 2007年第2X期48卷 299-303页

作者： YANG Chun-Nuan YU Jia-lu WANG qu-quan HUANG Nian-Ning Department of Physics Wuhan University Wuhan 430072 China

Since the Jost solutions of the DNLS equation does not tend to the free Jost solutioins as ｜λ｜→∞, the usual inverse scattering transform （IST） must be revised. Beside the Kaup and Newell＇s approach, we propose a simple revision in constructing the equations of IST, where the usual Zakharov-Shabat kern is revised by multiplying λ^-2 or λ^-1. To justify the revision we show that the Jost solutions obtained do satisfy the pair of compatibility equations.

关键词： inverse scattering transform soliton solutions Liouville theorem

Research of simulation and experiment on arc characteristics of gas mechanical switch

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High Voltage 2024年第3期9卷 626-635页

作者： Cheng Jiang lu qu Zhangqing Yu Zhizheng Gan Xin yan Rong Zeng Yulong Huang Shaofu Li Department of Electrical Engineering Tsinghua UniversityBeijingChina School of Information Engineering Southwest University of Science and TechnologyMianyangChina Sichuan Energy Internet Research Institute Tsinghua UniversityChengduChina

An arc is the high-temperature discharge plasma produced in the opening process of mechanical switches,which directly affects the breaking capability of a hybrid DC circuit *** to the physical mechanism of an electric arc,the construction of an arc model for simulation analysis is an important technical means in the electrical *** this study,based on the theory of magneto hydrodynamics(MHD),a gas mechanical switch model of a natural commutation DC circuit breaker with a compound gap is *** arc motion process under different conditions is simulated and *** influence of different initial pressures,different opening speeds,and different striking currents on the arc voltage characteristics is *** results show that the larger the gas pressure,the smaller the arc volume and the higher the arc *** faster the opening speed,the longer the arc and the higher the arc voltage;with the increase of the current,the arc voltage increases rapidly at a low current,while the arc voltage increases slowly at a high current.

关键词： characteristics striking slowly

Nitrogen and boron co-doped graphene nanoribbons as peroxidase-mimicking nanozymes for enhanced biosensing

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Chinese Chemical Letters 2022年第1期33卷 344-348页

作者： Siyu luo Meng Sha Fei Tian Xialian Li Lijie Fu Yingqiu Gu lu-lu qu Guo-Hai Yang Chengzhou Zhu School of Chemistry&Materials Science Jiangsu Normal UniversityXuzhou 221116China Key Laboratory of Pesticide and Chemical Biology of Ministry of Education International Joint Research Center for Intelligent Biosensing Technology and HealthCollege of ChemistryCentral China Normal UniversityWuhan 430079China

The rational design of nanozymes with superior activities is essential for improving bioassay ***,nitrogen and boron co-doped graphene nanoribbons(NB-GNRs)are prepared by a hydrothermal method using urea as the nitrogen source and boric acid as the boron source,*** introduction of co-doped and edge structures provides high defects and active *** resultant NB-GNRs nanozymes show superior peroxidase-like activities to nitrogen-doped and boron-doped counterparts due to the synergistic *** taking advantage of their peroxidase-like activities,NB-GNRs are used for the first time to develop enzyme-linked immunosorbent assay for the detection of *** biosensors exhibit a high performance with a linear range from 0.001 ng/mL to 1000 ng/mL and a detection limit of 0.3 pg/*** to their low cost and high stability,the proposed nanomaterials show great promise in biocatalysis,immunoassay development and environmental monitoring.

关键词： Graphene nanoribbons Heteroatom doping Nanozymes Biosensing Interleukin-6