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Estimation methods of eco-environmental water requirements: Case study

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Science china Earth Sciences 2005年第8期48卷 1280-1292页

作者： YANG Zhifeng1,2, CUI Baoshan1 & LIU Jingling 1. School of Environment, beijing Normal university, beijing 100875, china 2. state key Joint laboratory of Environmental Simulation and Pollution control, beijing 100875, china School of Environment Beijing Normal University Beijing China state key Joint laboratory of Environmental Simulation and Pollution control Beijing China

Supplying water to the ecological environment with certain quantity and quality is significant for the protection of diversity and the realization of sustainable development. The conception and connotation of eco-environmental water requirements, including the definition of the conception, the composition and characteristics of eco-environmental water requirements, are evaluated in this paper. The classification and estimation methods of eco-environmental water requirements are then proposed. On the basis of the study on the Huang-Huai-Hai Area, the present water use, the minimum and suitable water requirement are estimated and the cor-responding water shortage is also calculated. According to the interrelated programs, the eco-environmental water requirements in the coming years (2010, 2030, 2050) are estimated. The result indicates that the minimum and suitable eco-environmental water requirements fluc-tuate with the differences of function setting and the referential standard of water resources, and so as the water shortage. Moreover, the study indicates that the minimum eco-environmental water requirement of the study area ranges from 2.84×1010m3 to 1.02×1011m3, the suitable water requirement ranges from 6.45×1010m3 to 1.78×1011m3, the water shortage ranges from 9.1×109m3 to 2.16×1010m3 under the minimum water requirement, and it is from 3.07×1010m3 to 7.53×1010m3 under the suitable water requirement. According to the different values of the water shortage, the water priority can be allocated. The ranges of the eco-environmental water re-quirements in the three coming years (2010, 2030, 2050) are 4.49×1010m3?1.73×1011m3, 5.99×10m3?2.09×1011m3, and 7.44×1010m3?2.52×1011m3, respectively.

关键词： eco-environmental water requirements, assessment methods, Huang-Huai-Hai area.

A new class of impulse stochastic control models with non-negative control quantity

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Science china(Information Sciences) 2011年第3期54卷 638-652页

作者： LIU XiaoPeng & LIU KunHui College of Science, beijing jiaotong university, beijing 100044, china College of Science Beijing Jiaotong University Beijing China

This paper advances and studies a new class of impulse stochastic control models. Its state structure is defined by a linear stochastic differential equation of the semi-martingale, its control cost function is a twovariable function of pre-control state quantity and control quantity, and its control quantity is kept non-negative. First this paper constructs a new type of variational equations and proves its solution exists. Using a series of stochastic analysis methods to research the solution function of this type of variational equations, this paper proves the existence of optimal control and analyzes its structure in depth. Because of the big difference between the model in this paper and stochastic control models in previous papers, the analysis method here is quite different from previous ones. It is expected that this paper will have important theoretical significance for stochastic control research, along with wide applicative value in finance control and security management.

关键词： impulse stochastic control control quantity variational equation optimal control semi-martingale

A HIGH-ORDER-ACCURATE DIFFERENCE SCHEME WITH UNCONDITIONAL STABILITY FOR THE DIFFUSION EQUATION ON NONUNIFORM GRIDS

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Journal of Hydrodynamics 2001年第1期13卷 92-98页

作者： Wang Xuan, Yang Zhi-feng state key laboratory of Environment Simulation and Pollution control, Institute of Environmental Sciences, beijing Normal university, beijing 100875, china[WT5”HZ] beijing Normal Univ. Beijing 100875 China

WT5”BZ]A high-order-accurate difference scheme with unconditional stability is developed for the diffusion equation on nonuniform grids. The theoretical analysis shows that the accuracy of this scheme is between third order and fourth order, and fourth-order accuracy is achieved in the case of the same grid steps being used within the computational domain. Two numerical examples are given to demonst ate the advantages of the proposed scheme. Compared with the conventional difference scheme, more accurate numerical solution can be obtained by using the proposed scheme even with relatively larger grid sizes. It is also pointed out that the appropriate structure of the nonuniform grid can not only make the proposed scheme more practical, but lead to a solution superior to that for a uniform grid structure. [WT5”HZ]

关键词： ]finite difference scheme diffusion equation nonuniform grid high accuracy computational fluid dynamics

Effect of CH3OOH on the atmospheric concentration of OH radicals

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Progress in Natural Science:Materials International 2006年第11期16卷 1141-1149页

作者： WANG Caixia and CHEN Zhongming**(The state key laboratory of Environmental Simulation and Pollution control, College of Environmental Sciences, Peking university, beijing 100871, china) The state key laboratory of Environmental Simulation and Pollution control College of Environmental Sciences Peking University Beijing 100871 China

Methyl hydroperoxide （CH3OOH, MHP） is known to be a significant sink and reservoir of HOx and ROx radicals in the atmosphere. In order to investigate the impact of MHP on the concentration of atmospheric OH radicals, two key gas-phase reactions of MHP, i.e. the reactions with OH radicals and with UV photolysis, have been simulated at temperature of 293±2 K and total pressure of 1.01×105 Pa, using the long path Fourier transform infrared （LP-FTIR） spectrometry. OH radicals are generated by the photolysis of O3 in the presence of water vapor. Combined with the relative rate method, the reaction rate constant of MHP with OH radicals is determined to be （3.99±0.15）×10 -12 cm3·molecule -1 ·s -1 , and thus the atmospheric lifetime of MHP is estimated at 2.9 days. Furthermore, from detailed analysis of the UV photolysis of MHP, the yield of OH radicals is obtained to be 0.91±0.04. Based on the MHP atmospheric lifetime and the yield of OH radicals, it is concluded that MHP plays an essential role in the redistribution of OH radicals in the troposphere.

关键词： OH radicals methyl hydroperoxide rate coefficient UV photolysis gas-phase reaction LP-FTIR.

Influence of the cobalt concentration on optical and magnetic properties of zinc oxide

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Chinese Science Bulletin 2010年第10期55卷 897-901页

作者： WANG LiWei,ZHANG FuJun,XU Zheng,ZHAO SuLing & LU LiFang Institute of Optoelectronics Technology,beijing jiaotong university key laboratory of Luminescence and Optical Information (beijing jiaotong university),Ministry of Education,beijing 100044,china Institute of Optoelectronics Technology Beijing Jiaotong University Beijing China Ministry of Education Key Laboratory of Luminescence and Optical Information (Beijing Jiaotong University) Beijing China

A series of Co-doped ZnO thin films have been prepared by direct current reactive magnetron sputtering on glass *** structural characterization by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) gave no evidence of second phase *** qualitative composition and chemical state were characterized by energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectronic spectrometry (XPS),*** results confirmed that Co was incorporated as Co3+,occupying the Zn2+ sites in ZnO's wurtzite *** luminescence properties of the films were investigated by room temperature photoluminescence,and the optical properties were studied by optical *** magnetic analysis was carried out at room temperature and at 50 K by Quantum Design MPMS (SQUID) *** results showed that all the Co-doped ZnO thin films prepared by direct current magnetron sputtering were not ferromagnetic above 50 K.

关键词：氧化锌钴氧化物磁性直流反应磁控溅射 X射线光电子能谱室温光致发光扫描电子显微镜纤锌矿结构

PRINCIPLES OF RIVER TRAINING AND MANAGEMENT

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International Journal of Sediment Research 2007年第4期22卷 247-262页

作者： Zhaoyin WANG1, Shimin TIAN2, Yujun YI3, and Guoan YU4 1 Prof., state key laboratory of Hydroscience and Engineering, Tsinghua university, beijing, 100084, china 2 Ph. D., china Institute of Water Resources and Hydro-Power Research, beijing 100044, china. 3 Ph. D., state key laboratory of Hydroscience and Engineering, Tsinghua university, beijing, 100084, china 4 Ph. D., state key laboratory of Hydroscience and Engineering, Tsinghua university, beijing, 100084, china state key laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China china Institute of Water Resources and Hydro-Power Research Beijing 100044 China

River regulation and river training have been performed for various purposes and negative effects have been shown in numerous cases. In some cases the negative effects are so serious that humans have to consider to "renaturalize" the regulated rivers. Only by using the strategy of integrated river management the diverse river uses and natural fluvial processes and ecological systems may be harmonized. Based on analysis of case studies and data collected from literatures this paper presents the concept of integrated river management and four principles of river training. The integrated river management comprises: 1) taking the watershed, upper stream basin including the tributaries, middle and lower reaches and the estuary as an integrated entity in the planning, design and management; and 2) mitigating or controlling the negative impacts on hydrology, erosion and sedimentation, fluvial processes, land use and river use, environment and ecology while in achieving economic benefit from water resources development, flood safety management and hydropower exploitation. River training and management should be in accordance with the four principles: 1) extending the duration of river water flowing on the continent, which may be achieved by extending the river course or reducing the flow velocity; 2) controlling various patterns of erosions and reducing the sediment transportation in the rivers; 3) increasing the diversity of habitat and enhancing the connectivity between the river and riparian waters; and 4) restoring natural landscapes.

关键词： River training Integrated river management Sediment Erosion control Ecological and landscape restoration

Asymptotic Analysis for Low-Resolution Massive MIMO Systems with MMSE Receiver

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china Communications 2018年第9期15卷 189-199页

作者： Kai Liu Cheng Tao Liu Liu Tao Zhou Yinsheng Liu Institute of Broadband Wireless Mobile Communications School of Electronics and Information Engineering Beijing Jiaotong University National Mobile Communications Research laboratory Southeast University state key laboratory of rail traffic control and safety Beijing Jiaotong University

The uplink achievable rate of massive multiple-input-multiple-output(MIMO) systems, where the low-resolution analog-to-digital converters(ADCs) are assumed to equip at the base station(BS), is investigated in this paper. We assume that only imperfect channel station information is known at the BS. Then a new MMSE receiver is designed by taking not only the Gaussian noise, but also the channel estimation error and quantizer noise into account. By using the Stieltjes transform of random matrix, we further derive a tight asymptotic equivalent for the uplink achievable rate with proposed MMSE receiver. We present a detailed analysis for the number of BS antennas through the expression of the achievable rates and validate the results using numerical simulations. It is also shown that we can compensate the performance loss due to the low-resolution quantization by increasing the number of antennas at the BS.

关键词： massive MIMO low-resolution quantization MMSE receiver

Reinvestigation of the Henry's law constant for hydrogen peroxide with temperature and acidity variation

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Journal of Environmental Sciences 2010年第4期22卷 570-574页

作者： Daoming Huang,Zhongming Chen The state key laboratory of Environmental Simulation and Pollution control,College of Environmental Sciences and Engineering,Peking university,beijing 100871,china. The state key laboratory of Environmental Simulation and Pollution control College of Environmental Sciences and Engineering Peking University Beijing 100871 China

Hydrogen peroxide is not only an important oxidant in itself; it also serves as both sink and temporary reservoir for other important oxidants including HOx （OH and HO2） radicals and O3 in the atmosphere. Its partitioning between gas and aqueous phases in the atmosphere, usually described by its Henry＇s law constant （KH）, significantly influences its role in atmospheric processes. Large discrepancies between the KH values reported in previous work, however, have created uncertainty for atmospheric modelers. Based on our newly developed online instrumentation, we have re-determined the temperature and acidity dependence of KH for hydrogen peroxide at an air pressure of （0.960 ± 0.013） atm （1 atm = 1.01325 × 10^5 Pa）. The results indicated that the temperature dependence of KH for hydrogen peroxide fits to the Van＇t Hoff equation form, expressed as lnKH = a/T - b, and a = -△H/R, where KH is in M/atm （M is mol/L）, T is in degrees Kelvin, R is the ideal gas constant, and AH is the standard heat of solution. For acidity dependence, results demonstrated that the KH value of hydrogen peroxide appeared to have no obvious dependence on decreasing pH level （from pH 7 to pH 1）. Combining the dependence of both temperature and acidity, the obtained a and b were 7024 ± 138 and 11.97 ± 0.48, respectively, AH was （58.40 ± 1.15） kJ/（***）, and the uncertainties represent σ. Our determined KH values for hydrogen peroxide will therefore be of great use in atmospheric models.

关键词： hydrogen peroxide Henry's law constant atmosphere acidity

Micromechanical analysis of interaction energy for SMA reinforced composite

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Science china(Technological Sciences) 2009年第3期52卷 610-616页

作者： ZHU YuPing1,2, DUI GuanSuo1 & DUO Liu3 1 Institute of Mechanics, beijing jiaotong university, beijing 100044, china 2 Department of Engineering Mechanics, Jiangsu university, Zhenjiang 212013, china 3 state key Lab of Crystal Materials, Shandong university, Jinan 250100, china Institute of Mechanics Beijing Jiaotong University Beijing China Department of Engineering Mechanics Jiangsu University Jiangsu China state key Lab of Crystal Materials Shandong University Jinan China

The energy of the interaction between the matrix and the inclusions in shape memory alloy (SMA) re- inforced composite is one of the most important and complicated parts in thermodynamic constitutive theory. In this paper, the interaction energy is derived based on the classical theory of micromechanics and the thermodynamic theory. The SMA composite is treated as three phases, namely the austenitic phase, the martensite phase and the matrix phase. The interaction among the three phases is analyzed in a way close to the fact. The present expression is used to calculate the interaction energy of a typical SMA composite with attentions paid to understand of the effects of the matrix material, the fiber ge- ometry, and the fiber/matrix volume ratio. It is shown that the method developed in this paper is credible compared with the references. Some useful conclusions are obtained.

关键词： shape memory alloy interaction energy SMA composite micromechanics thermodynamics