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EFFECT OF PAN-MILLING ON RHEOLOGICAL PROPERTIES OF HIGH DENSITY POLYETHYLENE

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Chinese Journal of Polymer Science 2000年第5期18卷 397-403页

作者： Hua Huang Polymer research institute, Sichuan University, Chengdu 610065, china Sichuan Univ Polymer Res Inst Chengdu 610065 Peoples R China Shanghai Jiao Tong Univ Sch Chem & Chem Technol Shanghai 200240 Peoples R China

The effect of pan-milling on the rheological properties of high density polyethylene (HDPE) was studied. An innovative milling apparatus, viz. an inlaid pan-mill, was used. Melt indexer, capillary rheometer, Haake Rheocord 90 single-screw extruder and Brabender rheometer were used to evaluate the rheological properties of HDPE. HDPE with higher initial molecular weight and larger particle size was easier to degrade under pan-milling stress, as indicated by the melt index. Pressure oscillation in capillary flow occurred at significantly higher shear stress and shear rate for milled HDPE than for unmilled HDPE. The apparent shear viscosity of HDPE decreased with increasing times of milling. After milling, the flow activation energy decreased and thus the sensitivity of viscosity to temperature was reduced. Die pressure and torque during single screw extrusion were reduced significantly after milling. Plasticizing time as measured in a Brabander mixer decreased markedly with increasing milling times.

关键词： high density polyethylene rheological properties pan-milling

Designing regional pattern for ecosystem restoration:A case study

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Science china(Technological Sciences) 2006年第z1期49卷 86-97页

作者： LI Guoqiang , MA Keming, FU Bojie & LIU Shiling State Key Lab of Systems Ecology, research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, china Department of water Environment, china institute of water Resources and Hydropower research, Beijing 100038, china School of Environmental Sciences, Beijing Normal University, Beijing 100875, china 1. State Key Lab of Systems Ecology Research Center for Eco-environmental Sciences Chinese Academy of Sciences Beijing 100085 China 2. Department of water Environment China Institute of Water Resources and Hydropower Research Beijing 100038 China 3. School of Environmental Sciences Beijing Normal University Beijing 100875 China

Designing regional pattern is challenging for ecosystem restoration both in theory and in practice. The present study proposed a new approach to design regional pattern for ecosystem restoration with a case in the arid valley of Upper Minjiang River, SW china. The procedures are: (1) Determine the regional pattern of main environmental factors based on the relationships between the important environmental factors and the main geographical factors generated from DEM data. (2) Overlay the maps of the main environmental factors. (3) Generate a lookup table according to the species selection rule we proposed to link the candidate restoration species to the main environmental factors.(4) Determine the regional pattern of ecosystem restoration by positioning the restoration species in the map of environmental factors according to the lookup table. The regional restoration pattern designed in this way would be applicable not only to restoring a region, but also to predicting the future landscape change.

关键词： environmental factors, GIS, restoration species, Upper Minjiang River Valley.

STABILITY ANALYSIS OF RIVERBANK SUBJECT TO SEEPAGE

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International Journal of Sediment research 2007年第4期22卷 282-291页

作者： Yan LU1, Yongjun LU2, and Xingnong ZHANG3 1 Postdoctoral Fellow, Nanjing Hydraulic research institute, State Key Laboratory of Hydrology water Resources and Hydraulic Engineering Science, Nanjing, china 210029. 2 Prof., Nanjing Hydraulic research institute, Nanjing, china 210029 3 Prof., Nanjing Hydraulic research institute, Nanjing, china 210029. Nanjing Hydraul Res Inst Nanjing 210029 Peoples R China

The stability of riverbanks subject to seepage is studied experimentally and theoretically in this paper. By including seepage in a 3-dimensional theoretical analysis, the study first shows how the critical slope or angle of repose of a cohesionless material is related to the ratio of the hydraulic gradient of seepage to its critical value under the fluidization condition. The critical stable slope is shown to be related to not only the hydraulic gradient but also the seepage direction. Measured laboratory data reasonably fit well with the theoretical relationship for the case of injection and suction. The data reveal that the slope is reduced with injection and increased with suction, respectively. Additionally, the study identifies the seepage direction which results in a minimum critical stable slope for a certain hydraulic gradient of seepage.

关键词： Seepage Riverbank Stability Critical stable slopes Angle of repose Erosion

Present geotemperature and its suggestion to natural gas generation in Xujiaweizi fault-depression of the northern Songliao Basin

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Science china Earth Sciences 2008年第S1期51卷 207-220页

作者： ZHOU QingHua 1,2 ,FENG ZiHui 3 &MEN GuangTian 3 1 research institute of Petroleum Exploration and Development,Petrochina,Beijing 100083,china 2 Geological Logging Subcompany of Daqing Oil Field Company Ltd.,Daqing 163411,china 3 research institute of Petroleum Exploration and Development of Daqing Oil field Company Ltd.,Daqing 163732,china Petrochina Res Inst Petr Explorat & Dev Beijing 100083 Peoples R China Daqing Oil Field Co Ltd Geol Logging Subco Daqing 163411 Peoples R China Daqing Oil field Co Ltd Res Inst Petr Explorat & Dev Dacling 163732 Peoples R China

According to stastistic of present geotemperatures at the depths of 1000,2000,3000 and 4000 m,respectively in the Xujiaweizi fault-depression of the north Songliao Basin,the result indicates that Xujiaweizi fault-depression falls in the high geotemperature area,with the higher geothermal gradient in the depression layer than that in the fault-depression *** geothermal gradient decreases with the increasing of the *** thermal conductivity of rock greatly controls the geothermal *** main factors constraining the current geotemperature include thermal configuration of the earth's crust, deep faults,distribution and abundance of *** high geotemperature is in favour of generation of deep gas.

关键词： Xujiaweizi fault-depression geotemperature geothermal gradient thermal conductivity of rock deep layer natural gas

Establishing time-dependent model of deformation modulus caused by bedrock excavation rebound by inverse analysis method

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Science china(Technological Sciences) 2008年第S2期51卷 1-7页

作者： WU ZhongRu1,2,GU YanChang1,3,GU ChongShi1,2,GUO HaiQing1 & SU HuaiZhi1,2 1 Hohai University,Nanjing 210098,china 2 National Engineering research Center of water Resources Efficient Utilization and Engineering Safety,Nanjing 210098,china 3 Nanjing Hydraulic research institute,Nanjing 210029,china 1. Hohai University Nanjing 210098 China 2. National Engineering research Center of water Resources Efficient Utilization and Engineering Safety Nanjing 210098 China 3. Nanjing Hydraulic research institute Nanjing 210029 China

Rock rebound relaxation deformation,or even rock burst,caused by the excavation of dam base and abutment or high rock slope affects their stability and results in the fall of mechanical properties of the *** an inverse analysis method was proposed in this paper to establish the time-dependent model of deformation modulus caused by excavation *** basic principle is based on the combination of observed data of the excavation rebound deformation of dam abutment or rock slope,and the calculated rebound deformation by FEM under ground stress at the corresponding time in the excavation *** norm of the residuals of observed data and calculated data are taken as the objective ***,the time-dependent model of bedrock deformation modulus can be *** method displays its significance in the design of excavation,construction and operation management of dam base and high slope.

关键词： dam base rebound deformation modulus inverse analysis method time-dependent model Xiaowan Hydropower Station

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峡江防护区地下水中铁离子运移规律研究

水电能源科学 2011年第6期29卷 40-42页

作者：詹青文张建华江西省水利规划设计院江西南昌320029

针对峡江水利枢纽工程同江防护区地下水环境可能恶化的问题,选取黏土、砂壤土、细砂做了小土柱运移试验和静态吸附试验,研究分析了铁离子在三类土壤中的运移规律及吸附模式。结果表明,铁离子在三类土壤中的吸附均符合Langmuir等温非线... 详细信息

针对峡江水利枢纽工程同江防护区地下水环境可能恶化的问题,选取黏土、砂壤土、细砂做了小土柱运移试验和静态吸附试验,研究分析了铁离子在三类土壤中的运移规律及吸附模式。结果表明,铁离子在三类土壤中的吸附均符合Langmuir等温非线性吸附模式,吸附能力由强到弱顺序为黏土、砂壤土、细砂,运移速度由快到慢依次为细砂、砂壤土、黏土,可为评价峡江水利枢纽工程修建前后同江防护区地下水环境的变化提供理论依据。

关键词：同江防护区地下水铁离子迁移规律静态吸附试验

COUPLING EFFECT OF SEEPAGE FLOW AND RIVER FLOW ON THE BANK FAILURE

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Journal of Hydrodynamics 2011年第6期23卷 834-840页

作者： NING Bo WU- Shi-qiang TAN Ye-fei XIE Xing-hua YAN Jun YAN Zhong-min GENG Yan-qiong College of water conservancy and Hydropower Engineering Hohai University Nanjing 210098 China Nanjing Hydraulic research institute Nanjing 2100-29 China Nanjing Hydraulic research institute.Nanjing 210029 China Lian Yungang Technical College Lian Yungang 222000 China

On the basis of the generalized physical model of the riverbank, the experiments were conducted to study the mechanisms of riverbank failure under the coupling effect of seepage flow and river flow. The experimental setup was specially designed, as well as test point location, parameters and procedures, and the main influencing factors were analyzed affecting riverbank failure based on the failure types, the variations of pore water pressure and soil displacement. The results indicated that the coupling effect has different influences on the bank failure in three aspects： the failure type, the process and the extent. In addition, the river flow played a more important role than the seepage flow in the coupling effect on the bank failure.

关键词： bank failure seepage flow river flow physical model test

One-dimensional numerical simulation of non-uniform sediment transport under unsteady flows

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International Journal of Sediment research 2008年第4期23卷 316-328页

作者： Hongwei FANG 1,Minghong CHEN 2,and Qianhai CHEN 31 Prof.,Dept.of Hydraulic Engineering,Tsinghua Univ.,State Key Laboratory of Hydroscience and Engineering,Beijing,100084,china 2 PhD,College of water conservancy and Civil Engineering,china Agricultural Univ.,Beijing 100083,china.3 Engineer,institute of the Yangtze River research,Wuhan,430010,china [a]Prof. Dept. of Hydraulic Engineering Tsinghua Univ. State Key Laboratory of Hydroscience and Engineering Beijing 100084 china [b]PhD College of water conservancy and Civil Engineering china Agricultural Univ. Beijing 100083 china [c]Engineer institute of the Yangtze River research Wuhan 430010 china

One-dimensional numerical models are popularly used in sediment transport research because they can be easily programmed and cost less time compared with two-and three-dimensional numerical *** particular,they possess greater capacity to be applied in large river basins with many *** paper presents a one-dimensional numerical model capable of calculating total-load sediment *** cross-section-averaged sediment transport capacity and recovery coefficient are addressed in the suspended load *** one-dimensional model,therefore,can be applied to fine suspended loads and to hyperconcentrated flows in the Yellow ***,a new discretization scheme for the equation of unsteady non-uniform suspended sediment transport is *** model is calibrated using data measured from the Yantan Reservoir on the Hongshui River and the Sanmenxia Reservoir on the Yellow River.A comparison of the calculated water level and river bed deformation with field measurements shows that the improved numerical model is capable of predicting flow,sediment transport,bed changes,and bed-material sorting in various situations,with reasonable accuracy and reliability.

关键词： One-dimensional numerical model Sediment transport capacity Recovery coefficient Adaptation length Unsteady flow

The Energy Growth Property for Harmonic Maps

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Chinese Quarterly Journal of Mathematics 1996年第1期11卷 53-55页

作者： Li Hongyi Zhao Di(North china institute of water conservancy and Hydroelectric Power, Zhengzhou, 450045 ) 华北水利电力学院河南郑州 450045 华北水利电力学院河南郑州

In this paper,we study the energy growth property for a class of harmonic maps. A special estimation of energy growth is obtained.

关键词： harmonic maps energy density