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Agronomic performances of biodegradable and non-biodegradable plastic film mulching on a maize cropping system in the semi-arid Loess Plateau,china

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Pedosphere 2024年第1期34卷 88-96页

作者： hao ZHANG Mengqiong CHEN Ruiquan QIAO Fan ding hao FENG Rui JIANG Research Center for Cultural Landscape Protection and Ecological Restoration China-Portugal Belt and Road Cooperation Laboratory of Cultural Heritage Conservation ScienceGold Mantis School of ArchitectureSoochow UniversitySuzhou 215006China Key Laboratory of Plant Nutrition and the Agri-environment in Northwest china Ministry of AgricultureCollege of Natural Resources and EnvironmentNorthwest A&F UniversityYangling 712100China College of Land and Environment Shenyang Agricultural UniversityShenyang 110866China Institute of Soil and Water Conservation Northwest A&F UniversityYangling 712100China

Biodegradable plastic film mulch (PFM) is considered an alternative to non-biodegradable PFM to mitigate the negative impacts of residual ***,the agronomic performance of biodegradable PFM in comparison to non-biodegradable PFM still needs to be *** this study,we evaluated the effects of biodegradable and non-biodegradable PFM on soil physicochemical properties,microbial community,and enzyme activities,as well as maize growth *** and non-biodegradable PFM both increased soil temperature,water content,N content,and microbial biomass and maize yield by up to 30%,but decreased soil enzyme activities as compared to no mulching (control,CK).Most soil physicochemical properties,microbial community,and enzyme activities were similar under non-biodegradable and biodegradable PFM at the early stages of maize ***,at the late stages,soil temperature,water content,mineral N,NO_(3)^(-)-N,ammonia monooxygenase (AMO) activity,and total phospholipid fatty acids (PLFAs) decreased under biodegradable PFM owing to film *** PFM increased soil temperature,water content,and total PLFAs at the early stages of maize growth but decreased soil mineral N and total PLFAs at the late stages,as compared to black *** soil temperature and N availability were the major factors affecting soil microbial community,microbial activity decreased after the fragmentation of biodegradable PFM,owing to the decreased soil temperature,water content,and mineral ***,biodegradable PFM could decrease NO_(3)^(-)-N accumulation in topsoil by decreasing N transformation due to the lower microbial and N-related enzyme (e.g.,AMO) activities,compared with non-biodegradable PFM,which may avoid negative environmental impacts,such as NO_(3)^(-)-N leaching or gas emission after *** yield,height,aboveground biomass,and N uptake under biodegradable PFM were similar to those under non-biodegradable PFM during maize growth,implying that biodegrad

关键词： black plastic film mulching enzyme activity film fragmentation microbial community phospholipid fatty acid white plastic film mulching

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Microstructure and Mechanical Properties of Nb-Microalloyed X100 High Deformability Pipeline Steel

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Journal of Iron and Steel Research International 2011年第S1期18卷 707-711页

作者： MENG De-liang 1,KANG Yong-lin 1,AN Shou-yong 2.XIA Dian-xiu 2.SUN hao 2.zheng Xiao-fei 1 (1.{2. of materials science and Engineering,university of science and Technology beijing,beijing 100083,china 2.Technology Center of Jinan Iron and Steel Co.,Ltd.,Jinan 2.0101,Shangdong,china) Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Jinan Iron & Steel Co Ltd Ctr Technol Jinan 250101 Shangdong Peoples R China

A low carbon Nb-microalloyed high deformability pipeline steel with X100 grade has been processed by TMCP and followed two-stage cooling *** microstructure is characterized by ferrite/bainite *** effective grain size is 1.85μm in *** volume of ferrite is about 10-15% and the grains sizes are mostly less than 5μ*** bainite consists of granular-bainite and lath-bainite,with M/A islands finely *** longitudinal tensile yield strength,uniform elongation,yield ratio are 647MPa,7.6% and 0.78,***/bainite multiphase have large strain hardenability that resulting high strength and high deformability *** of Nb also improves the strength and uniform deformability by precipitation strengthening and grain refinement.

关键词： pipeline steel high deformability high strength microalloyed steel strain based design

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In-situ growth and photoluminescence of β-Ga_2._3 cone-like nanowires on the surface of Ga substrates

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science china(Technological sciences) 2009年第6期52卷 1712-1721页

作者： LIU RuiNi1,YANG HeQing1,ZHANG RuiGang1,DONG HongXing1,CHEN XiaoBo1,LI Li1,ZHANG LiHui1,MA JunHu1 & zheng HaiRong2.1 Key Laboratory of Macromolecular science of Shaanxi Province,{2. of Chemistry and materials science,Shaanxi Normal university,Xi’an 710062.china 2.{2. of Physics & Information Technology,Shaanxi Normal university,Xi’an 710062.china 1. Key Laboratory of Macromolecular science of Shaanxi Province School of Chemistry and Materials Science Shaanxi Normal University Xi’an 710062 China 2. school of Physics & Information Technology Shaanxi Normal University Xi’an 710062 China

β-Ga2.3 cone-like nanowires have been in-situ grown on the surface of gallium grains and films by heating gallium substrates at 750-1000℃ for 2. in *** controllable synthesis of β-Ga2.3 nano-wires with different diameters and lengths was achieved by adjusting the heating temperature and *** as-synthesized products were characterized by means of X-ray diffraction,scanning electron mi-croscopy and transmission electron *** results showed that the β-Ga2.3 nanowires are single crystalline with a monoclinic structure and have a controllable diameter and length in the range of 30-100nm and 0.5-1.5μm,respectively.A possible mechanism was also proposed to account for the formation of β-Ga2.3 cone-like *** spectra of the β-Ga2.3 nanowires obtained at different temperatures were measured at room temperature,and a strong blue photolumi-nescence with peaks at 430 and 460nm and a weak red photoluminescence with peak at 713nm were *** blue light emission intensity decreases with increasing the reaction temperature,how-ever,the red light emission intensity hardly *** blue and red light emissions originate from the recombination of an electron on an oxygen vacancy with a hole on a gallium-oxygen vacancy pair and the nitrogen dopants,etc.,respectively.

关键词： β-Ga2.3 cone-like nanowires photoluminescence in-situ growth

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Development on Technique of Tube Reducing in Double 3-Roll Dies

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International Journal of Minerals,Metallurgy and materials 2000年第1期14卷 55-57页

作者： Baolong zheng Li Sun Ruichen An , Lianshi Li Material science and Engineering {2., university of science and Technology beijing, beijing 100083, china No. 1 Steel Rolling Factory, Tangshan Iron and Steel Corporation, Tangshan 063000, china Material science and Engineering school University of Science and Technology Beijing Beijing 100083 China No.1 Steel Rolling Factory Tangshan Iron and Steel Corporation Tangshan 063000 China

Based on the experiments, a new technique of reducing tube with two linked 3-roll roller dies was developed. The external friction conditions, velocity and the non-uniform deformation of metal were distinctly improved, and the friction between metal and tool was decreased. Corrosion strip layers and photo-elastic coatings methods were adopted in the experiment for measuring residual stress, and the residual stresses in the drawn tube with 3-roll dies are reduced.

关键词： reducing tube roller dies drawing deformation

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Secondary Hardening, Austenite Grain Coarsening and Surface Decarburization Phenomenon in Nb-Bearing Spring Steel

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Journal of Iron and Steel Research International 2012年第3期19卷 47-51,61页

作者： ZHANG Chao-lei, LIU Ya-zheng, ZHOU Le-yu, JIANG Chao (school of materials science and Engineering, university of science and Technology beijing, beijing 100083, china) school of materials {2. and Engineering University of Science and Technology Beijing Beijing 100083 China

The secondary hardening, the austenite grain coarsening and the surface decarburization phenomenon of Nb-bearing spring steel were investigated, and the effects of niobium on tempered microstructure was studied using scanning electron microscope. The results show that the micro-addition of niobium increases the tempering resistance and produces secondary hardening. The effect of niobium on the size and distribution of cementite particles is one of the primary reasons to increase the hardness after tempering. The grain-coarsening temperature of the spring steel is raised 150 ~C due to Nb-addition. Furthermore, both the secondary hardening and the austenite grain coarsening phenomenon congruously demonstrate niobium begins observably dissolving above 1 100 ℃ in the spring steel. Be- sides, niobium microalloying is an effective and economy means to decrease the decarburization sensitivity of the spring steels.

关键词： spring steel! microalloyingl secondary hardening grain coarsening surface decarburization

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Numerical simulation of profile control by clay particles after polymer flooding

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Petroleum science 2010年第4期7卷 509-514页

作者： Feng Qihong Shi Shubin Wang Sen zheng Lu school of Petroleum Engineering China University of Petroleum Qingdao Shandong 266555 China school of Petroleum Engineering China University of Petroleum Beijing 102249 China Shengli Oil Production Research Institute SINOPEC Dongying Shandong 257000 China Bozhong Operation Company CNOOC Tianjin 300452 China

A three-dimensional,two-phase,five-component mathematical model has been developed to describe flow characteristics of clay particles and flocs in the profile control process,in which the clay particle suspension is injected into the formation to react with residual *** model considers the reaction of clay particles with residual polymer,apparent viscosity of the mixture,retention of clay particles and flocs,as well as the decline in porosity and permeability caused by the retention of clay particles and flocs.A finite difference method is used to discretize the equation for each component in the *** Runge-Kutta method is used to solve the polymer flow equation,and operator splitting algorithms are used to split the flow equation for clay particles into a hyperbolic equation for convection and a parabolic equation for diffusion,which effectively ensures excellent precision,high speed and good *** numerical simulation had been applied successfully in the 4-P192. unit of the Lamadian Oilfield to forecast the blocking capacity of clay particle suspension and to optimize the injection parameters.

关键词： Clay particles flocs detention operator splitting algorithms numerical simulation

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The Study on the Microstructure and Mechanical Properties of 400MPa Grade Bar Prepared by Controlled Cooling After Finish Rolling

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Journal of Iron and Steel Research International 2011年第S1期18卷 610-614页

作者： ZHANG Jun-wei 1,ding Lei 1,XIAO Yi 2.3,HU Xiao-dong 1,HU Lin 1 (1.school of {2. and Metallurgy,university of science and Technology Liaoning,Anshan 114051,Liaoning,china 2.Baosteel Nantong Co Ltd.,Nantong 2.6002.Jiangsu,china 3.school of Electrical Engineering,Anhui university of Technology,Maanshan 2.3002.Anhui,china) Univ Sci & Technol Liaoning Sch Met & Mat Anshan 114051 Liaoning Peoples R China Baosteel Nantong Co Ltd Nantong 226002 Jiangsu Peoples R China Anhui Univ Technol Sch Elect Engn Maanshan 243002 Anhui Peoples R China

The production process of bars in Baosteel Nantong *** adjusted by both decreasing heating temperature and adding controlling cooling procedure after finish rolling for upgrade of bars.A set of water cooling system was also installed behind the finishing ***-line tests were conducted,and then the microstructure and mechanical properties of the bars with HRB335 composition and φ2.mm diameter were *** results showed that the microstructures of the bar cooled by water were ferrite and pearlite with grain sizes of 8.5 to 12.grades,which were finer than that of the bar without water *** the thin outer layer microstructures of the bar cooled by water were mainly tempered sorbite with small amount of tempered *** average yield strength R eL and tensile strength R m of the bars with water cooling increased 105MPa and 73MPa respectively compared with those of the bars without water *** reason of this strengthening was attributed to the synthetic role of fine grains and phase transformation and precipitation *** addition,The ration of R m /R eL could be higher than 1.2.,which is the request of earthquake-proof performance for HRB400E,only when the self-tempering temperatures of the bars were higher than 640℃.

关键词： controlled cooling hot rolling bar fine grain strengthening self-tempering

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Studies on the microstructure,optical and electrical properties of organic microcavity devices based on a porous silicon reflector

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science china(Technological sciences) 2005年第2期48卷 191-201页

作者： XIONG Zuhong1, FAN Yongliang2. ZHAN Yiqiang2. ZHANG Songtao2. ding Xunmin2.& HOU Xiaoyuan2.1. school of Physics, Southwest{2.-Normal university, Chongqing 400715,{2. 2. Surface Physics Laboratory (National Key Laboratory), Fudan university, Shanghai 2.0433,{2. 1. school of Physics Southwest China-Normal University 400715 Chongqing China 2. Surface Physics Laboratory (National Key Laboratory) Fudan University 200433 Shanghai China

A novel type of microcavity organic light-emitting diode based on a porous silicon distributed Bragg reflector (PS-DBR) has first been achieved and its microstructure, optical, and electrical properties have also been investigated in detail. The microcavity is made up of the central active organic multilayer sandwiched between a top silver film and a bottom PS-DBR, formed by electrochemical etching of p++-Si substrate. The field- emission scanning electron microscopy cross-section images show the nanometer-scale layered structure and flat interfaces inside the microcavity. The reflectivity (relative to an Al mirror) of the PS-DBR is up to 99%, and the stopband is about 160 nm wide. Resonant cavity mode appears as a tip in the reflectivity spectrum of the Si-based organic multilayer films, which is a symbol that the Si-based organic multilayer structure is indeed a microcavity. The peak widths of the electroluminescence (EL) spectra from the cavities emitting green and red light are greatly reduced from 85 nm and 70 nm to 8 nm and 12.nm, respectively, as compared with those measured from non-cavity structures. Note that the EL emission from the cavity devices is single-mode, and the off-resonant optical modes are highly suppressed. Moreover, increases of a factor of about 6 and 4 of the resonant peak intensity from the cavities emitting green and red light are also observed, respectively. In addition, the current-brightness-voltage characteristics and effect parameters on the lifetime of the cavity devices are also discussed. The present technique for obtaining enhanced EL emission from Si-based organic microcavity may also be another novel effective method for realizing Si-based optoelectronics device integration.

关键词： electrochemical etching, Si-based microcavity, electroluminescence, organic light-emitting diodes.

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The influence of impurity on the critical thickness of the CeO_2.buffer layer for coated conductors

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science china(Physics,Mechanics & Astronomy) 2009年第7期52卷 993-996页

作者： PAN Min1, HUANG zheng2. MA HuanFeng2. QIANG WeiRong2. WEI LianFu1, WANG Long2.& Zhao Yong1,3 1 Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of E{2.cation of china), Supercon{2.ctivity R&D Center (SRDC), Southwest Jiaotong university, Cheng{2. 610031, china 2.school of Physical science and Technology, Southwest Jiaotong university, Cheng{2. 610031, china 3 Supercon{2.ctivity Research Group, school of materials science and Engineering, university of New South Wale, Sydney, 2.52.NSW, Australia Key Laboratory of Magnetic Levitation Technologies and Maglev Trains (Ministry of Education of china) Superconductivity R&D Center (SRDC) Southwest Jiaotong University Chengdu 610031 China school of Physical science and Technology Southwest Jiaotong University Chengdu 610031 China Superconductivity Research Group School of Materials Science and Engineering University of New South Wale Sydney 2052 NSW Australia

The lattice parameters, band structure, density of state and elastic constant of RE-doped CeO2.(RE=Sm, Gd, Dy), the buffer material for coated HTS conductors, are calculated using the plane-wave method with pseudopotentials based on the density functional theory (DFT) of first-principle. The rule and mechanism of the effect of rare earth impurity on the critical thickness of the CeO2.buffer layer are investigated. It is found that, in the range of the calculation, the changes of the lattice volume V and elastic constant E of CeO2.with the impurity are mainly determined by the increased electrons ne of the system. The relationship of the elastic constant E and increased electrons ne is established. It is indicated that the critical thickness of the CeO2.single buffer layer doped with Sm, Gd, and Dy may be enhanced by 2.%, 43% and 33%, respectively.

关键词： CeO2 first principle critical thickness elastic constants

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Structure Relaxation of Mg_(65)Cu_(2.)Gd_(10) Metallic Glass and Its Effect on Strength

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Journal of Wuhan university of Technology(materials {2.) 2009年第2期24卷 210-213页

作者：李国强 school of materials {2. & Engineering Beijing University of Aeronautics and Astronautics china Perfect Machinery Industry Corp. Ltd

To identify the re-arrangement of constituent atoms of an amorphous Mg65Cu2.Gd10 alloy happened with annealing, structure relaxation of the alloy was investigated as a function of an- nealing time at 373 K through extended X-ray absorption fine structure （EXAFS） analysis procedures. To understand the effect of structure relaxation on strength, compression tests were conducted for both the as-cast and the annealed Mg65Cu2.Gd10 samples. It is found that short range order around Cu and Gd atoms exhibits different variation trends with increasing annealing time at 373 K, though the structure of the alloy still remains to be amorphous. Based on the fact that the strength of the alloy first exhibits a reduction and then a recovery with annealing time, it is suggested that the enhancement of short range order around Cu should be responsible for the strength reduction, while the enhancement of short range order around Gd should be responsible for the strength recovery.

关键词： Mg-based metallic glass structure relaxation strength annealing

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