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Estimation of non-point source pollution loads with flux method in Danjiangkou Reservoir area,China

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Water Science and Engineering 2017年第2期10卷 134-142页

作者： Xiao-kang Xin Wei Yin ke-feng li State key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Changjiang Water Resources Protection Institute Changjiang Water Resources Commission

The estimation of non-point source pollution loads into the Danjiangkou Reservoir is highly significant to environmental protection in the watershed. In order to overcome the drawbacks of traditional watershed numerical models, a base flow separation method was established coupled with a digital filtering method and a flux method. The digital filtering method has been used to separate the base flows of the Hanjiang,Tianhe, Duhe, Danjiang, Laoguan, and Qihe rivers. Based on daily discharge, base flow, and pollutant concentration data, the flux method was used to calculate the point source pollution load and non-point source pollution load. The results show that:(1) In the year 2013, the total inflow of the six rivers mentioned above accounted for 95.9% of the total inflow to the Danjiangkou Reservoir. The total pollution loads of chemical oxygen demand(CODMn) and total phosphorus(TP) from the six rivers were 58.20 103 t and 1.863 10~3 t, respectively, and the non-point source pollution loads were 39.82 10~3 t and 1.544 10~3 t, respectively, indicating that the non-point source pollution is a major factor(with a contribution rate of 68.4% for CODMnand 82.9% for TP).(2) The Hanjiang River is the most significant contributor of pollution loads to the Danjiangkou Reservoir, and its CODMnand TP contribution rates reached 79.3% and 83.2%, respectively. The Duhe River took the second place.(3) Non-point source pollution mainly occurred in the wet season in 2013, accounting for 80.8% and 90.9% of the total pollution loads of CODMnand TP, respectively. It is concluded that the emphasis of pollution control should be placed on non-point source pollution.

关键词： Danjiangkou Reservoir Non-point source pollution Base flow separation Digital filtering method (DFM) Flux method

Effects of gas supersaturation on lethality and avoidance responses in juvenile rock carp(Procypris rabaudi Tchang)

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2010年第10期11卷 806-811页

作者： Xiang HUANG ke-feng li Jun DU Ran li State key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 China Fisheries Institute Sichuan Academy of Agricultural Sciences Chengdu 611731 China

Laboratory experiments were conducted to determine the effects of total dissolved gas （TDG） supersaturation on acute lethality and avoidance responses in juvenile rock carp （Procypris rabaudi Tchang）. The juvenile rock carp were exposed to water with different levels of supersaturation （105%, 115%, 120%, 125%, 130%, 135%, 140%, and 145%） and depth of 0.20 m at 25℃ for 60 h. Median lethal time （LT50） was used to assess the lethal responses corresponding to different levels of gas supersaturation. The results show that half of the juvenile rock carp died at the 120%, 125%, 130%, 135%, 140%, and 145% levels of supersaturation, and the LT50 corresponding to different levels of supersaturation was 18.7, 15.4, 8.2, 6.6, 3.5, and 1.7 h. When the level of supersaturated water is below 115%, the mortality is negligible. Avoidance responses were observed 5 min after the fish were put into equilibrated water （99%, 0.08 m deep） and water with different supersaturated levels （105%, 115%, 125%, 135%, and 145%, 0.08 m deep） at 25 ℃. The fish exhibited strong avoidance responses in supersaturated water when the gas supersaturation was above 135%. However, they exhibited an obvious preference to supersaturated water when the gas supersaturation was below 115%. Thus, the juvenile rock carp can likely survive in water with a supersaturated level of 115%.

关键词： Gas supersaturation Lethality Avoidance Juvenile rock carp (Procypris rabaudi Tchang)

Influence of total dissolved gas-supersaturated water on silver carp(Hypophthalmichthys molitrix)

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Water Science and Engineering 2016年第4期9卷 324-328页

作者： Lu Cao Rui-feng liang You-cai Tuo Yong li ke-feng li State key Laboratory of Hydraulics and Mountain River Engineering Sichuan University

Dam discharges over spillways are the main reason for the gas-supersaturated water generated in *** aquatic organisms,especially fish,readily develop gas bubble disease(GBD) in a river with total dissolved gas supersaturation(TDGS).Sometimes,fish will die after a specific exposure period,which negatively affects the biological *** this study,the influence of TDGS on silver carp was *** carp were exposed to gas-supersaturated water with TDGS levels of 140%,135%,130%,125%,120%,and 110%to test the impact of *** silver carp died when the TDGS level was 120%or higher,and all the silver carp exposed to a TDGS level of 140%died within10 *** comparison with the Chinese sucker,Prenant's schizothoracin,and rock carp,silver carp seem less sensitive to *** addition,we tested the catalase(CAT) activity in the muscles and gills of silver carp after they were exposed to gas-supersaturated water with a TDGS level of140%.The CAT activity changed with time;it increased first and then decreased until it was lower than the initial CAT *** results of this study can provide basic data for developing a standard for environmental evaluation.

关键词： Total dissolved gas supersaturation Silver carp CAT activity Gas bubble disease Median lethal time Median lethal concentration

Growth rate,catalase and superoxide dismutase activities in rock carp(Procypris rabaudi Tchang) exposed to supersaturated total dissolved gas

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第11期12卷 909-914页

作者： Xiao-qing liU ke-feng li Jun DU Jia li Ran li State key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 China Fisheries Institute Sichuan Academy of Agricultural Sciences Chengdu 611731 China

Total dissolved gas supersaturation(TDGS) appears when the pressures of gases in a solution exceed the barometric *** is often caused by flood discharge at *** may lead to gas bubble disease(GBD) for fish and biochemical responses of selected fish and other aquatic *** purpose of this study was to determine the impact of long-term TDGS levels on the growth and biochemical responses of rock carp(Procypris rabaudi Tchang) dwelling in the upper reaches of the Yangtze ***-year-old rock carp were exposed to TDGS levels at 100%,104%,108%,112%,and 116% for 42 *** were taken every 7 d after the start of the trial in order to determine catalase(CAT) and superoxide dismutase(SOD) activities in gill and muscle *** were taken at Days 0 and 42 of exposure to determine growth *** effect was found on growth rate in all treatment *** and CAT activities varied in different tissues,according to time of exposure and TDGS *** biochemical response of fish exposed to TDGS was more obvious in gill tissue than in muscle *** of SOD and CAT activities in different tissues offer important information about the effect of TDGS on the rare fish in the Yangtze River,and may help evaluate the risk to the aquatic eco-environment and aquatic ecosystem in the downstream of the Yangtze River.

关键词： Total dissolved gas supersaturation (TDGS) Rock carp (Procypris rabaudi Tchang) Growth rate Catalase Superoxide dismutase

Electrodeposition and characterization of thermoelectric Bi_2Se_3 thin films

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International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 104-107页

作者： Xiao-long li ke-feng Cai Hui li ling Wang Chi-wei Zhou Functional Materials Research Laboratory Tongji University Shanghai 200092 China

Bi2Se3 thin films were electrochemically deposited on Ti and indium tin oxide-coated glass substrates, respectively, at room temperature, using Bi（NO3）3·5H2O and SeO2 as starting materials in diluted HNO3 solution. A conventional three-electrode cell was used with a platinum sheet as a counter electrode, and a saturated calomel electrode was used as a reference electrode. The films were annealed in argon atmosphere. The influence of cold isostatic pressing before annealing on the microstructure and thermoelectric properties of the films was investigated. X-ray diffraction analysis indicates that the film grown on the indium tin oxide-coated glass substrate is pure rhombohedral Bi2Se3, and the film grown on the Ti substrate consists of both rhombohedral and orthorhombic Bi2Se3.

关键词： thermoelectric thin films bismuth selenide electrodeposition thermoelectric properties cold isostafic pressing

Evaluation, prediction, and protection of water quality in Danjiangkou Reservoir, China

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Water Science and Engineering 2015年第1期8卷 30-39页

作者： Xiao-kang Xin ke-feng li Brian Finlayson Wei Yin State key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Changjiang Water Resources Protection Institute Changjiang Water Resources Commission Department of Resource Management and Geography the University of Melbourne

The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project （SNWDP）, which commenced transferring water in 2014. Integrated research on the evaluation, prediction, and protection of water quality in the Danjiangkou Reservoir was carried out in this study in order to improve environmental management. Based on 120 water samples, wherein 17 water quality indices were measured at 20 monitoring sites, a single factor evaluation method was used to evaluate the current status of water quality. The results show that the main indices influencing the water quality in the Danjiangkou Reservoir are total phosphorus （TP）, permanganate index （CODM,）, dissolved oxygen （DO）, and five-day biochemical oxygen demand （BODs）, and the concentrations of TP, BODs, ammonia nitrogen （NH3--N）, CODM,, DO, and anionic surfactant （Surfa） do not reach the specified standard levels in the tributaries. Seasonal Mann--kendall tests indicated that the CODMn concentration shows a highly significant increasing trend, and the TP concentration shows a significant increasing trend in the Danjiangkou Reservoir. The distribution of the main water quality indices in the Danjiangkou Reservoir was predicted using a two-dimensional water quality numerical model, and showed that the sphere of influence from the tributaries can spread across half of the Han Reservoir if the pollutants are not controlled. Cluster analysis （CA） results suggest that the Shending River is heavily polluted, that the Jianghe, Sihe, and Jianhe rivers are moderately polluted, and that they should be the focus of environmental remediation.

关键词： Water quality Single factor evaluation method Mann--kendall test Numerical modeling Cluster analysis Dangjiangkou Reservoir

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

Numerical study of heat transfer of gas-atomized Fe-6.5 %Si （mass and solidification behavior fraction） droplets

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Advances in Manufacturing 2016年第2期4卷 150-156页

作者： ke-feng li Yun-Hu Zhang Chang-Jiang Song Qi-Jie Zhai State key Laboratory of Advanced Special Steel School ofMaterials Science and Engineering Shanghai UniversityShanghai 200072 People's Republic of China

During spray atomization process, the heat transfer and solidification of droplets play very important roles for the deposition quality. Due to the difficulties of experimental approach, a numerical model is developed, which integrates liquid undercooling, nucleation recalescence and post-re- calescence growth to present the full solidification process of Fe-6.5%Si （mass fraction） droplet. The droplet velocity, temperature, cooling rate as well as solid fraction profiles are simulated for droplets with different sizes to demonstrate the critical role of the size effect during the solidification process of droplets. The relationship between the simulated cooling rate and the experimentally obtained secondary dendrite arm spacing is in excellent agreement with the well-established formula. The pre-constant and exponent values lie in the range of various rapid solidified Fe-based alloys reported, which indicates the validity of the numerical model.

关键词： Fe-6.5%Si (mass fraction) alloy Gasatomization Solidification - Heat transfer Numericalsimulation

Microstructural Features and Mechanical Behaviors of Al_(0.5)Cr_(0.8)CoFeNi_(2.5)V_(0.2) High-Entropy Alloys Fabricated by Selective Laser Melting Technique

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Acta Metallurgica Sinica(English Letters) 2022年第10期35卷 1591-1606页

作者： Yao Yan Wei-Dong Song ke-feng li Kang Zhao Tong-Tong Sun Kai-Kai Song Jian-Hong Gong li-Na Hu Shenzhen Research Institute of Shandong University Shenzhen518057China State key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081China Guangdong Institute of Materials and Processing Guangdong Academy of SciencesGuangdong UniversityGuangzhou510650China School of Mechanical Electrical and Information EngineeringShandong UniversityWeihai264209China key Laboratory for liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) Shandong UniversityJinan250061China

In this work,high strength and ductile Al_(0.5)Cr_(0.8)CoFeNi_(2.5)V_(0.2) high-entropy alloys(HEAs)were fabricated by the selective laser melting(SLM)*** orthogonal experiments,it was verified that a wide SLM processing parameter window can be used to produce crack-free samples for the investigated *** the printed HEA samples exhibit good densification higher than 98.3%.It was found that obvious epitaxial growth leads to the formation of the cylindrical and equiaxed ordered face-centered cubic(FCC)crystals,displaying the characteristics of sub-cylindrical and sub-cellular *** low-angle grain boundaries(LAGBs)prefer appearing around subgrain structures,while the high-angle grain boundaries(HAGBs)tend to form around coarse *** HEA samples with high and low apparent densities were selected to observe their mechanical properties,which exhibit Vickers hardness higher than 263 HV and do not fail during *** increasing densification,the strength gradually *** to the engineering stress–strain curves during compression,the yield strength is higher than 530 MPa,while the strength near 40%engineering strain is larger than 1840 *** deformation,a large density of dislocations becomes popular within subgrain structures together with the pre-existing dislocations from rapid solidification,leading to the formation of planar and cross slip *** coarse cylindrical crystals,some deformation twins are also induced together with the appearance of a distinct copper-type texture during *** a result,the as-printed samples display better mechanical properties than the as-cast *** present studies provide a very good HEA candidate for the SLM process,but more work should be conducted to achieve excellent comprehensive properties.

关键词： High-entropy alloys Selective laser melting Mechanical properties Microstructures