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STUDY AND APPLICATION OF STEADY FLOW AND UNSTEADY FLOW MATHEMATICAL MODEL FOR CHANNEL NETWORKS

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Journal of Hydrodynamics 2007年第5期19卷 572-578页

作者： ZHANG Ming-liang SHEN Yong-ming State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

Based on the Preissmann implicit scheme for the one-dimensional Saint-Venant equation, the mathematical model for one-dimensional fiver networks and canal networks was developed and the key issues on the model were expatiated particularly in this article. This model applies the method of three-steps solution for chaunel-junction-channel to simulate the river networks, and the Gauss elimination method was used to calculate the sparse matrix. This model was applied to simulate the tree-type irrigation canal networks, complex looped channel networks and the Lower Columbia Slough networks. The results of water level and discharge agree with the data from the Adlul and field data. The model is proved to be robust for simulating unsteady flows in river networks with various degrees of complex structure. The calculated results show that this model is useful for engineering applications in complicated river networks. Future research was recommended to focus on setting up ecological numerical model of water quality in river networks and canal networks.

关键词： Preissmann implicit scheme canal networks and river networks unsteady flow ecological numerical model

Effects of Temperature and Water Saturation on CO_2 Production and Nitrogen Mineralization in Alpine Wetland Soils

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Pedosphere 2009年第1期19卷 71-77页

作者： GAO Jun-Qin OUYANG Hua XU Xing-Liang ZHOU Cai-Ping ZHANG Feng Beijing Forestry University Beijing 100083 （China） Institute of Geographic Sciences and Natural Resources research Chinese Academy of Sciences Beijing 100101 （China） Graduate University of the Chinese Academy of Sciences Beijing 100049 （China）

Relationships between carbon (C) production and nitrogen (N) mineralization were investigated in two alpine wetland soils of the Tibetan Plateau using laboratory incubation under different temperatures (5, 15, 25, and 35 ℃) and water saturation (noninundation and inundation). A significant positive relationship was found between CO2 production and N mineralization under increasing temperatures from 5 to 35 ℃ with the same water saturation condition in the marsh soil (r2 > 0.49, P 0.38, P 0.70, P 0.61, P < 0.013). In conclusion, temperatures and water saturation could regulate the relationship between CO2 production and net N mineralization in the Tibetan alpine marsh and peat soils.

关键词： CO2产量氮矿化温度水饱和度湿地

NUMERICAL SIMULATIONS OF VISCOELASTIC FLOWS THROUGH ONE SLOT CHANNEL

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Journal of Hydrodynamics 2007年第2期19卷 210-216页

作者： YIN Hong-jun ZHONG Hui-ying FU Chun-quan WANG Lei Key Laboratory of Enhanced Oil and Gas Recovery of Ministry of Education Daqing Petroleum Institute Daqing 163318 China Oil Recovery Plant No. 1 Daqing Oilfield Corp. Ltd. Daqing 163001 China

In this article, the Modified Upper-Convected Maxwell equation （MUCM） is proposed. The viscoelastic polymer solution flow characteristics are described by the numerical method. The stream function contour, velocity contour and stress modulus contour of fluid in slot channel are drawn. The non-Newtonian power law property and viscoelasticity of MUCM fluid influence on the stream function are analyzed. The velocity contour move towards dead oil area with the viscoelasticity increase, flow area increase and the sweep area enlarges, so the sweep efficiency is enhanced.

关键词： viscoelastic fluid Modified Upper-ConvectedMaxwell （MUCM） constitutive equation power law exponent,Weissenberg number

A virtual service placement approach based on improved quantum genetic algorithm

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Frontiers of Information Technology & Electronic Engineering 2016年第7期17卷 661-671页

作者： Gang XIONG Yu-xiang HU Le TIAN Ju-long LAN Jun-fei LI Qiao ZHOU national Digital Switching System Engineering&Technological research Center Zhengzhou 450002China Department of Mathematics and Computer Science University of AntwerpAntwerp 2020Belgium

Despite the critical role that middleboxes play in introducing new network functionality,management and innovation of them are still severe challenges for network operators,since traditional middleboxes based on hardware lack service flexibility and scalability.Recently,though new networking technologies,such as network function virtualization(NFV) and softwaredefined networking(SDN),are considered as very promising drivers to design cost-efficient middlebox service architectures,how to guarantee transmission efficiency has drawn little attention under the condition of adding virtual service process for traffic.Therefore,we focus on the service deployment problem to reduce the transport delay in the network with a combination of NFV and SDN.First,a framework is designed for service placement decision,and an integer linear programming model is proposed to resolve the service placement and minimize the network transport delay.Then a heuristic solution is designed based on the improved quantum genetic algorithm.Experimental results show that our proposed method can calculate automatically the optimal placement schemes.Our scheme can achieve lower overall transport delay for a network compared with other schemes and reduce 30% of the average traffic transport delay compared with the random placement scheme.

关键词： Software-defined networking(SDN) Network function virtualization Quantum genetic algorithm Middlebox

Effect of Waterlogged and Aerobic Incubation on Enzyme Activities in Paddy Soil

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Pedosphere 2006年第4期16卷 532-539页

作者： WANG Xiao-Chang LU Qin Department of Tea Science College of Agriculture and Biotechnology Zhejiang University Hangzhou 31002g （China） Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）

An incubation experiment with soil water content treatments of 0.15 (W1), 0.20 (W2), and 0.40 (W3) g g-1 soil was carried out for two months to investigate the activities of important enzymes involved in C, N, P, and S cycling in a paddy soil from the Taihu Lake region, china, under waterlogged and aerobic conditions. Compared with air-dried soil, waterlogging resulted in a significant decrease (P (?) 0.05) of fluorescein diacetate (FDA) andβ-D-glucosidase activities, and this effect was enhanced with increasing waterlogging time. Waterlogging also significantly inhibited (P (?)0.05) arylsulfatase as well as alkaline and acid phosphatase activities, but did not decrease the activities with the increase in waterlogging time. Short-term waterlogging did not affect urease activity, but prolonged waterlogging decreased it markedly. In contrast, the aerobic incubation (W1 and W2 treatments) significantly increased (P(?) 0.05) FDA, alkaline phosphatase, andβ-D-glucosidase activities. With aerobic treatments the activities of FDA and alkaline phosphatase increased with incubation time, whereasβ-D-glucosidase activity decreased. A significant difference (P (?) 0.05) was usually observed between the W1 and W2 treatments for the activities of FDA as well as alkaline and acid phosphatase; however,β-D-glucosidase and urease were usually not significant (P(?) 0.05). No activity differences were observed between waterlogging and aerobic incubation for arylsulfatase and urease.

关键词：需氧性酶活性稻田土水浸

THEORETICAL ESTIMATION OF GROUNDWATER DISCHARGE AND ASSOCIATED NUTRIENT LOADING TO A LAKE WITH GENTLE SLOPE BOTTOM

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Journal of Hydrodynamics 2007年第1期19卷 30-35页

作者： LI Yong WANG Chao College of Environmental Science and Engineering Hohai University Nanjing 210098 China

A simple estimation model of groundwater discharge and nutrient flux from nearshore unconfined aquifer to lake was studied. It was supposed that the aquifer was permeable isotropic homogeneously and its thickness approximated to the depth of lake. Distribution of the hydraulic gradient and the specific discharge along the transect of the discharge zone were discussed. Results show that the groundwater discharge patterns vary with the inclination angle of lakeshore bottom. For a shallow lake with gentle slope bottom, the rate of discharge of groundwater to lake is not constant across a discharge zone, but the discharge is concentrated in a narrow portion of the littoral zone where the Dupuit assumptions are invalid. The width of the discharge zone is correlative with aquifer thickness and slope of the lake bottom. The distribution functions of hydraulic gradient and groundwater discharge rates accord exponentially with offshore distance.

关键词： shallow lake unconfined aquifer groundwaterdischarge nutrient loading

GIS-Based Assessment of Land Suitability for Optimal Allocation in the Qinling Mountains, china

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Pedosphere 2006年第5期16卷 579-586页

作者： LIU Yan-Sui WANG Jie-Yong GUO Li-Ying Institute of Geographic Sciences and Natural Resources research Chinese Academy of Sciences Beijing 100101 （China） Graduate School of Chinese Academy of Sciences Beijing 100039 （China） College of Tourism and Environmental Sciences Shaanxi Normal University Xi＇an 710062 （China）

A GIS-based method was used to assess land suitability in the Qinling Mountains, Shaanxi Province of china through simultaneous consideration of physical features and current land use. Through interpretation of Landsat TM images and extensive field visits the area was modeled into 40 land types in five altitudinal zones (valleys and gullies, hillsides and terraces, foothills, mid-mountain, and sub-alpine mountain). Then, a suitability score was assigned to five physical factors (climate, hydrology, topography, soil, and vegetation). Next, their integrated overall suitability value scores were compared with the observed land cover to determine whether it should be reallocated a new use. Results showed that the five suitability classes of agriculture, forest, grassland, farmland-woodland, and scrub-pasture had altitudinal stratification and a total of 1151 km2 (8.89%) of lands on the northern slopes of the Qinling Mountains had to be reallocated. To achieve this reallocation, 657 km2 of arable land should be reduced, and forest, grassland and scrub-pasture increased by 615 km2, 131 km2 and 405 km2, respectively. Implementation of these recommended land reallocations should help achieve suitable use of land resources and prevent land degradation.

关键词： GIS系统地形秦岭适宜性土壤

An OpenFlow-based performance-oriented multipath forwarding scheme in datacenters

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Frontiers of Information Technology & Electronic Engineering 2016年第7期17卷 647-660页

作者： Bo LIU Ming CHEN Bo XU Hui HU Chao HU Qing-yun ZUO Chang-you XING College of Command Information Systems PLA University of Science and TechnologyNanjing 210007China PLA Academy of national Defense Information Wuhan 430020China

Although dense interconnection datacenter networks(DCNs)(e.g.,Fat Tree) provide multiple paths and high bisection bandwidth for each server pair,the widely used single-path Transmission Control Protocol(TCP)and equal-cost multipath(ECMP) transport protocols cannot achieve high resource utilization due to poor resource excavation and allocation.In this paper,we present LESSOR,a performance-oriented multipath forwarding scheme to improve DCNs' resource utilization.By adopting an Open Flow-based centralized control mechanism,LESSOR computes near-optimal transmission path and bandwidth provision for each flow according to the global network view while maintaining nearly real-time network view with the performance-oriented flow observing mechanism.Deployments and comprehensive simulations show that LESSOR can efficiently improve the network throughput,which is higher than ECMP by 4.9%–38.3% under different loads.LESSOR also provides 2%–27.7% improvement of throughput compared with Hedera.Besides,LESSOR decreases the average flow completion time significantly.

关键词： Datacenter network Traffic engineering Open Flow Multipath transmission

Plant Pb Contents in Elevation Zones of the Changbai Mountain national Nature Reserve, china

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Pedosphere 2007年第2期17卷 229-234页

作者： BAI Jun-Hong CUI Bao-Shan DENG Wei WANG Qing-Gai DING Qiu-Yi State Key Lab of Water Environment Simulation School of Environment Beijng Normal University 19 Xinjiekouwai Road Haidian District Beijing 100101 （China）. Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610051 （China） Appraisal Center of Environment and Engineering State Environment Protection Administration of China Beijing 100012 （China）

Typical plants and soils of four elevation zones, mountain tundra (Zone A), Betula ermanii forest (Zone B), mountain dark coniferous forest (Zone C), and mountain coniferous and broad-leaf forest (Zone D), along the vertical gradient of the northern mountain slope of the Changbai Mountain national Nature Reserve, Jilin Province, china, were sampled to study the relationship between plant and soil Pb, and to compare the Pb levels in typical plant types within the same elevation zone. The Pb contents in the soil and plant samples were measured by using a flame atomic absorption spectrophotometer. The results showed that the average plant Pb contents of the four plant elevation zones were lower than the average worldwide level, except for Zone B. Compared with the average level in china or the average worldwide level, the soil Pb levels of the four plant zones were higher, with Zones D and B having the lowest and highest averages, respectively. Plant Pb levels fluctuated from the upper to the lower zones, in a pattern of low-high-low-high, which was the same as that of the soils in the four zones. Furthermore, plant Pb was closely related to soil Pb. Depending on the plant species and plant parts, large differences were found in the Pb levels of typical plants within each zone. In Zone A, Vaccinium viiginosum and Rhododendron redowskianum had higher Pb levels than the other plants. In Zone C, the Pb levels in the branches of both plant species were higher than those in the leaves, which was contrary to Zone D. In Zone B, the Pb levels in the plant parts varied greatly with plant species.

关键词：长白山国家自然保护区植物铅含量高海拔地带铅污染