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An Analytical Solution for One-Dimensional Water Infiltration and Redistribution in Unsaturated Soil

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Pedosphere 2009年第1期19卷 104-110页

作者： WANG quan-Jiu R. HORTON fan Jun Institute of Water Resources Research Xi＇an University of Technology Xi＇an 710048 （China） State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water Resources Yangling 712100 （China） Department of Agronomy Iowa State University Ames IA 50011 （USA）

Soil infiltration and redistribution are important processes in field water cycle, and it is necessary to develop a simple model to describe the processes. In this study, an algebraic solution for one-dimensional water infiltration and redistribution without evaporation in unsaturated soil was developed based on Richards equation. The algebraic solution had three parameters, namely, the saturated water conductivity, the comprehensive shape coefficient of the soil water content distribution, and the soil suction allocation coefficient. To analyze the physical features of these parameters, a relationship between the Green-Ampt model and the algebraic solution was established. The three parameters were estimated based on experimental observations, whereas the soil water content and the water infiltration duration were calculated using the algebraic solution. The calculated soil water content and infiltration duration were compared with the experimental observations, and the results indicated that the algebraic solution accurately described the unsaturated soil water flow processes.

关键词： algebraic solution Green-Ampt model soil water infiltration and redistribution unsaturated soil

Facial Preparation of Magnetic Lipase as Efficient Biocatalyst to Resolute Esters Enantioselectively

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Chemical Research in Chinese Universities 2015年第6期31卷 997-1002页

作者： ZHANG Yanmei quan Chunshan LIU Baoquan fan Shengdi College of Life Science Dalian Nationalities University Dalian 116600 P R. China

Magnetic lipase was prepared by a facial and cost-effective method. Lipase from Pseudomonase cepacia was covalently linked to Fe304 nanoparticles, which were produced by co-precipitating Fe^2＋ and Fe^3＋ ions in ammonia solution and subsequent coating with 3,4-dihydroxylaldehyde. Magnetic Fe304 nanoparticles modified with 3,4-dihydroxylaldehyde bonded lipase efficiently（47 mg/g）. The resulting magnetic-lipase is active（0.68 μmol·min^-1·mg^-1） and enantioselective（e.e, of the product 〉98%） in the hydrolysis of racemic 1-phenylethyl acetate. Furthermore, as a heterogeneous catalyst, the magnetic-lipase can be magnetically recycled, and a retained activity of 48% was obtained even after 6 cycles.

关键词： Covalent attachment 3,4-Dihydroxylaldehyde Enantioselective hydrolysis Lipases from Pseudomonasecepacia Fe3O4 nanoparticle Recycle

Review of Large Spacecraft Deployable Membrane Antenna Structures

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Chinese Journal of Mechanical Engineering 2017年第6期30卷 1447-1459页

作者： zhi-quan Liu Hui Qiu Xiao Li Shu-Li Yang Beijing Institute of Spacecraft System Engineering China Academy of Space Technology Beijing 100094 China

The demand for large antennas in future space missions has increasingly stimulated the development of deployable membrane antenna structures owing to their light weight and small stowage volume. However, there is little literature providing a comprehensive review and comparison of different membrane antenna structures. Space-borne membrane antenna structures are mainly classified as either parabolic or planar membrane antenna structures. For parabolic membrane antenna structures, there are five deploying and forming methods, including inflation, inflation-rigidization, elastic ribs driven, Shape Memory Polymer （SMP）-inflation, and electrostatic form- ing. The development and detailed comparison of these five methods are presented. Then, properties of membrane materials （including polyester film and polyimide film） for parabolic membrane antennas are compared. Additionally, for planar membrane antenna structures, frame shapes have changed from circular to rectangular, and different ten- sioning systems have emerged successively, including single Miura-Natori, double, and multi-layer tensioning systems. Recent advances in structural configurations, tensioning system design, and dynamic analysis for planar membrane antenna structures are investigated. Finally, future trends for large space membrane antenna structures are pointed out and technical problems are proposed, including design and analysis of membrane structures,materials and processes, membrane packing, surface accuracy stability, and test and verification technology. Through a review of large deployable membrane antenna structures, guidance for space membrane-antenna research and applications is provided.

关键词： Membrane antenna. Parabolic Plane.Tensioning system Dynamics

RAMAN SPECTROSCOPIC STUDY ON THE CHAIN CONFORMATION OF ELECTROSYNTHESIZED POLY(ρ-PHENYLENE)FILMS

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Chinese Journal of Polymer Science 2005年第6期23卷 681-685页

作者： Feng-en Chen Ming-xiao Fu fan Wang Bin fan Gao-quan Shi Department of Chemistry Tsinghua University Beijing 100084 Department of Chemistry Qujing Normal Institute Qujing City 655000 China

Poly（p-phenylene）（PPP） films have been electrochemically deposited on mirrorlike stainless steel （SS） electrode surfaces by direct oxidation of benzene in boron trifluoride diethyl etherate （BFEE） solutions at a constant applied potential of 1.7 V （versus Ag/AgCl）. The chain conformations of as-grown PPP films have been studied by Raman spectroscopy. The results demonstrated that high synthesis temperature favors the formation of planar PPP, and the conformation of planar PPP can be changed into torsional PPP by cooling treatment.

关键词： Poly(p-phenylene) Raman spectroscopy Conformation

Comparison of CNT-PVA membrane and commercial polymeric membranes in treatment of emulsified oily wastewater

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Frontiers of Environmental Science & Engineering 2019年第2期13卷 95-103页

作者： Gang Yi Xinfei fan Xie quan Shuo Chen Hongtao Yu Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) School of Environmental Science and TechnologyDalian University of TechnologyDalian 116024China

Membrane separation is an attractive technique for removal of emulsified oily ***,polymeric membranes which dominate the current market usually suffer from severe membrane ***,membranes with high fouling resistance are imperative to treat emulsified oily *** this study,carbon nanotube-polyvinyl alcohol(CNT-PVA)membrane was *** its separation performance for emulsified oily wastewater was compared with two commercial polymeric membranes(PVDF membrane and PES membrane)by filtration of two homemade emulsions and one cutting fluid *** results show that these membranes have similar oil retention efficiencies for the three ***,the permeation flux of CNT-PVA membrane is 1.60 to 3.09 times of PVDF membrane and 1.41 to 11.4 times of PES membrane,***,after five consecutive operation circles of filtration process and back flush,CNT-PVA membrane can recover 62.3% to 72.9% of its initial pure water ***,the pure water flux recovery rates are only 24.1% to 35.3% for PVDF membrane and 6.0% to 26.3% for PES membrane,***,CNT-PVA membrane are more resistant to oil fouling compared with the two polymeric membranes,showing superior potential in treatment of emulsified oily wastewater.

关键词： Oily wastewater Microfiltration Carbon nanotube membrane Commercial polymeric membrane

The Promoting Effect of Multifunctional Groups on the Thermal and Mechanical Properties of PVC Materials

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Journal of Renewable Materials 2023年第2期11卷 867-880页

作者： Mei Wang Xinzhu fan Xianghai Song quan Bu School of Agricultural Engineering Jiangsu UniversityZhenjiang212013China Institute of the Green Chemistry and Chemical Technology School of Chemistry and Chemical EngineeringJiangsu UniversityZhenjiang212013China

The development of PVC materials grafted with mannich base originated from myrcene(P-MAM-g,where the mannich base derived from myrcene is abbreviated as MAM)via green and effective synthetic methods is a good strategy to avoid unacceptable discoloration and deterioration of thermal and mechanical properties caused by autocatalytic dehydrochlorination(DHC)during PVC *** this study,MAM with double bonds,amino groups,ester groups,and phospholipid groups was introduced into the chains of PVC to improve the thermal stability of *** experimental results showed that the covalent attachment of MAM to PVC enhanced both the initial and the long-term stability of *** enhanced performance of P-MAM-g compared with unmodified PVC is attributed to the simultaneous introduction of double bonds and amino groups into the PVC *** double bonds trapped the unstable chlorine atoms originated from the degradation of the PVC chain and reacted with the labile macromolecular radicals originated from PVC,thus inhibiting the radical degradation of the PVC ***,the amino groups absorbed the HCl produced in the degradation of PVC,inhibiting the adverse effects of HCl.P-MAM-g displayed better intrinsic flexibility and anti-migration ability of organic functional components compared with the control PVC materials.A possible stabilizing mechanism of the P-MAM-g was also presented.

关键词： Myrcene poly(vinyl chloride) covalent grafting self-stabilization

An Analytical Method for Relationship Between Hydraulic Diffusivity and Soil Sorptivity

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Pedosphere 2006年第4期16卷 444-450页

作者： WANG quan-Jiu ZHANG Jiang-Hui fan Jun State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences Yangling 712100 （China） Institute of Water Resources Research Xi＇an University of Technology Xi＇an 710048 （China） Northwest A ＆ F University Yangling 712100 （China）

A simple method was developed to relate soil sorptivity to hydraulic diffusivity and water absorption experiments were conducted utilizing one-dimensional horizontal soil columns to validate the relationship. In addition, an estimation method for hydraulic diffusivity with disc infiltrometer was developed. The results indicated a favorable fit of the theoretical relation to the experimental data. Also, the experiment with disc infiltrometer for estimating the diffusivity showed that the new method was feasible.

关键词： disc infiltrometer hydraulic diffusivity infiltration soil hydraulic parameter sorptivity

Variation in retained austenite content and mechanical properties of 0.2C–7Mn steel after intercritical annealing

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International Journal of Minerals,Metallurgy and Materials 2016年第2期23卷 161-167页

作者： Chuan Zhao Chi Zhang Wen-quan Cao zhi-gang Yang School of Materials Science and Engineering Tsinghua University Institute for Structural Materials Central Iron and Steel Research Institute

The effects of annealing time and temperature on the retained austenite content and mechanical properties of 0.2C-7Mn steel were *** retained austenite content of 0.2C-7Mn steel was compared with that of 0.2C-5Mn *** is found that 0.2C-7Mn steel exhibits a similar variation trend of retained austenite content as 0.2C-5Mn ***,in detail,these trends are different.0.2C-7Mn steel contains approximately 7.5vol%retained austenite after austenitization and *** stability of the reversed austenite in 0.2C-7Mn steel is lower than that in 0.2C-5Mn steel;in contrast,the equilibrium reversed austenite fraction of 0.2C-7Mn steel is substantially greater than that of 0.2C-5Mn ***,the retained austenite content in 0.2C-7Mn steel reaches 53.1vol%.The tensile results show that long annealing time and high annealing temperature may not favor the enhancement of mechanical properties of 0.2C-7Mn *** effect of retained austenite on the tensile strength of the steel depends on the content of retained austenite;in contrast,the 0.2%yield strength linearly decreases with increasing retained austenite content.

关键词： manganese steel annealing austenite mechanical properties

Hydrodynamic Performance of An Integrated System of Breakwater and A Multi-Chamber OWC Wave Energy Converter

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China Ocean Engineering 2024年第4期38卷 543-556页

作者： NING De-zhi ZHANG Xiang-yu WANG Rong-quan ZHAO Ming State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China Dalian Key Laboratory of Offshore Renewable Energy Dalian University of TechnologyDalian 116024China School of Computing Engineering and MathematicsUniversity of Western SydneyPenrith NSW 2751Australia

A multi-chamber oscillating water column wave energy converter(OWC-WEC)integrated to a breakwater is *** hydrodynamic characteristics of the device are analyzed using an analytical model based on the linear potential flow theory.A pneumatic model is employed to investigate the relationship between the air mass flux in the chamber and the turbine *** effects of chamber width,wall draft and wall thickness on the hydrodynamic performance of a dual-chamber OWC-WEC are *** results demonstrate that the device,with a smaller front wall draft and a wider rear chamber exhibits a broader effective frequency *** device with a chamber-width-ratio of 1:3 performs better in terms of power ***,results from the analysis of a triplechamber OWC-WEC demonstrate that reducing the front chamber width and increasing the rearward chamber width can improve the total performance of the *** the number of chambers from 1 to 2 or 3 can widen the effective frequency bandwidth.

关键词： oscillating water column power extraction efficiency potential flow theory wave energy converter multi-chamber