检索结果-南通市图书馆

Path analysis of sap flow of tomato under rain shelters in response to drought stress

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2016年第2期9卷 54-62页

作者： Shao Guangcheng Huang Doudou Cheng Xi cui jingtao Zhang Zhenhua Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil-Water Environment in Southern China Ministry of EducationCollege of Water Conservancy and Hydropower EngineeringHohai UniversityNanjing 210098China

The physiological characters and growth of tomato(Solanum lycopersicum L.)were recorded to be largely affected by different levels of *** objectives of this research were to determine the effects of deficit irrigation and rain shelters on sap flow,relative water content and the relationship between sap flow and environmental *** under rain shelters conditions were conducted in southern China during the growing seasons in *** threshold of irrigation was designed at 80%field capacity during the whole period(T1,the control),and 30%,40%and 50%decreased water of T1 were applied as the treatments of T2,T3 and *** plants subjected to water stress exhibited a decrease in the values of sap flow rate and relative water *** of 95%confidence level revealed a significant difference of sap flow rate in T4 and T3 as well as the control on sunny and rainy *** diurnal variation of the sap flow showed a single peak curve on sunny day,while it demonstrated irregular multi-peak variation on rainy *** study also showed that the most sensitive environmental indicator affecting sap flow was solar radiation,followed by air temperature and vapour pressure *** path coefficient was basically consistent with the coefficient of correlation,but there was slight difference between the total contribution R2 and that of variable factors.

关键词： drought stress tomato sap flow rain shelters deficit irrigation path analysis

Microstructure and Mechanical Properties of Intercritical Heat-affected Zone of X80 Pipeline Steel in Simulated In-Service Welding

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第7期28卷 883-891页

作者： Xin-Jie Di Lin Cai Xi-Xue Xing cui-Xin Chen Zhen-Kui Xue School of Materials Science and Engineering Tianjin University Tianjin Key Laboratory of Advanced Joining Technology School of Materials Science and Engineering Hebei University of Technology China Petrolum Pipeline Bureau

The intercritical heat-affected zone（ICHAZ） of X80 pipeline steel was simulated by using the Gleeble-3500thermal/mechanical simulator according to the thermal cycle of in-service *** microstructures of ICHAZ with different cooling rates were examined,and the hardness,the toughness and corresponding fractography were *** show that untransformed bainite and ferrite as well as retransformed fine bainite and martensite–austenite（M–A）constituents constitute the microstructure of *** two different morphologies of M–A constituents are stringer and *** phase particles which mainly composed of Ti,Nb,C,Fe and Cu coarsened in *** with normal welding condition,the toughness of ICHAZ is poor when the cooling time is short under in-service welding condition because of the large area fraction and size of M–A constituents that connect into chains and distribute at the grain *** Vickers hardness of ICHAZ that decreases with the increase in the cooling time is independent with the area fraction of M–A constituents.

关键词： X80 pipeline steel In-service welding Heat-affected zone Microstructure Toughness

Design and optimization of DBR in 980 nm bottom-emitting VCSEL

在线全文

学校读者我要写书评

暂无评论

Science in China(Series F) 2009年第7期52卷 1266-1271页

作者： LI Te NING YongQiang HAO ErJuan cui JinJiang ZHANG Yan LIU GuangYu QIN Li LIU Yun WANG LiJun cui DaFu XU ZuYan Key Laboratory of Excited State Processes Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy ofSciences Changchun 130033 China Heping Campus Jilin University Changchun 130033 China Institute of Physics Chinese Academy of Sciences Beijing 100080 China

According to the theory of DBR, with the P-type DBR as an example, the electrical characteristics and optical reflection of the DBR are analyzed by studying the energy band structure with various graded region widths and doping densities. The width and doping density of graded region are decided through a comparative study. The P-type DBR of 980 nm VCSELs is designed with Al0.9Ga0.1As and Al0.1Ga0.9As selected as the high and low refractive index material for the DBR. The 980 nm bottom VCSELs, which consists of 30 pairs P-type DBR and 28 pairs N-type DBR, are then fabricated. In P-type DBR, the width of graded region is 0.02 μm and the uniformity doping concentration is 2.5×10^18cm^-3. Its reflectivity is 99.9%. In N-type DBR, the width of graded region is also 0.02 μm and the uniformity doping concen- tration is 2×10^18cm^-3. Its reflectivity is 99.3%. The I-V curve shows that the series resistance of the device is about 0.05Ω. According to the theory of DBR, with the P-type DBR as an example, the electrical characteristics and optical reflection of the DBR are analyzed by studying the energy band structure with various graded region widths and doping densities. The width and doping density of graded region are decided through a comparative study. The P-type DBR of 980 nm VCSELs is designed, with Al0.9Ga0.1As and Al0.1Ga0.9As selected as the high and low refractive index material for the DBR. The 980 nm bottom VCSELs, which consist of 30 pairs P-type DBR and 28 pairs N-type DBR, are then fabricated. In P-type DBR, the width of graded region is 0.02μm and the uniformity doping concentration is 2.5×10^18cm^-3. Its reflectivity is 99.9%. In N-type DBR, the width of graded region is also 0.02 μm and the uniformity doping concentration is 2×10^18cm^-3. Its refiectivity is 99.3%. The I-V curve shows that the series resistance of the device is about 0.05Ω.

关键词： VCSEL DBR component graded series resistance reflectivity

Optimized design and test for a pendulum suspension of the crop spray boom in dynamic conditions based on a six DOF motion simulator

在线全文

学校读者我要写书评

暂无评论

International Journal of Agricultural and Biological Engineering 2018年第3期11卷 76-85页

作者： Longfei cui Hanping Mao Xinyu Xue Suming Ding Baiyu Qiao Key Laboratory of Modern Agricultural Equipment and Technology Ministry of EducationJiangsu UniversityZhenjiang 212013China Nanjing Research Institute for Agricultural Mechanization Ministry of AgricultureNanjing 210014China

Spray deposit distribution from a field sprayer is mainly affected by the boom movements when the tractor is driven over a rough soil surface,the pendulum suspension that used to reduce and control the movement of spray boom by isolating the boom from vibrations of the tractor will directly enhance uniform deposition of ***,how to match the parameters of the suspension with the properties of the boom is the key *** dynamic rigid-flexible coupling model of the virtual prototype of the spray boom suspension system was established by using ADAMS and ABAQUS *** optimization of the suspension parameters for a large spay boom was carried out based on the optimal Latin hypercube design,radial basis function neural network,and multi-objective genetic algorithm *** modified parameters of the suspension,the travel of the sprayer on a typical field motion track was simulated based on a six DOF motion simulator,and the dynamic behavior of the boom suspension was *** results show that RMS of the measured boom roll angle and the boom center displacement for optimized solution were reduced by 14.76%and 12.43%compared with the original ***,the inertial measurement unit(IMU)was used to measure the movements of the sprayer vehicle during the pesticide application on the Hongze Lake Farm,the experiment of field condition reproduced by using the six DOF motion simulator,the standard deviation of the roll angle and vibration displacement for the optimized sprayer boom are only 0.6382°and 62.279 mm *** research provides theoretical basis and experimental method for parameter optimization of large scale boom suspension.

关键词： boom sprayer pendulum suspension parameter optimization spray boom movement spray deposit distribution six DOF motion simulator

Online monitoring of gas-solid two-phase flow using projected CG method in ECT image reconstruction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2013年第2期11卷 204-215页

作者： Qi Wang Chengyi Yang Huaxiang Wang Ziqiang cui Zhentao Gao School of Electrical Engineering & Automation Tianjin University Oil Production Technology Research Institute of Huabei Oilfield Co.

Electrical capacitance tomography （ECT） is a promising technique for multi-phase flow measurement due to its high speed, low cost and non-intrusive sensing. Image reconstruction for ECT is an inverse problem of finding the permittivity distribution of an object by measuring the electrical capacitances between sets of electrodes placed around its periphery. The conjugate gradient （CG） method is a popular image reconstruction method for ECT, in spite of its low convergence rate. In this paper, an advanced version of the CG method, the projected CG method, is used for image reconstruction of an ECT system. The solution space is projected into the Kryiov subspace and the inverse problem is solved by the CG method in a low-dimensional specific subspace. Both static and dynamic experiments were carried out for gas-solid two-phase flows. The flow regimes are identified using the reconstructed images obtained with the projected CG method. The results obtained indicate that the projected CG method improves the quality of reconstructed images and dramatically reduces computation time, as compared to the traditional sensitivity, Landweber, and CG methods. Furthermore, the projected CG method was also used to estimate the important parameters of the pneumatic conveying process, such as the volume concentration, flow velocity and mass flow rate of the solid phase. Therefore, the projected CG method is considered suitable for online gas-solid two-phase flow measurement,

关键词： Electrical capacitance tomography (ECT) Image reconstruction Conjugate gradient method (CG) Krylov subspace

Statistical Analysis of Radio Interference of 1000 kV UHV AC Double-circuit Transmission Lines in Foul Weather

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2016年第2期2卷 47-55页

作者： Huichun Xie Xiang cui Baoquan Wan Jiangong Zhang State Key Laboratory of Alternate Electrical Power System with Renewable Source(NCEPU) Beijing 102206China China Electric Power Research Institute Wuhan 430074China

Analyzing the impact of radio interference(RI)variation during foul weather conditions is an area that has received limited *** paper provides a statistical analysis of RI measurements obtained from a long-term observation station close to the world’s first commercially operating 1000 kV UHV AC double-circuit transmission line in *** six months of observations,the impact of RI was studied on the line during fog,drizzle,and light snow and *** was found that RI increases linearly with the natural logarithm of the precipitation *** Levenberg-Marquardt algorithm(LMA)is employed to fit the RI value with the precipitation *** reasonable distribution of RI in different foul weather is verified by one-sample K-S *** test is seen as beneficial for further RI prediction based on statistical weather mode.

关键词： 1000 kV UHV AC double-circuit transmission line foul weather precipitation intensity radio interference statistical analysis

Driving forces for ultrafast laser-induced sp^(2) to sp^(3) structural transformation in graphite

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 1591-1597页

作者： Chenchen Song Mengxue Guan Yunzhe Jia Daqiang Chen Jiyu Xu cui Zhang Sheng Meng Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences100190 BeijingChina School of Physical Sciences University of Chinese Academy of Sciences100049 BeijingChina Songshan Lake Materials Laboratory 523808 DongguanGuangdongChina Present address:Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(Ministry of Education)School of PhysicsBeijing Institute of Technology100081 BeijingChina

Understanding the microscopic mechanism of photoinduced sp^(2)-to-sp^(3) structural transformation in graphite is a scientific challenge with great ***,the ultrafast dynamics and characteristics of laser-induced structural transformation in graphite are revealed by non-adiabatic quantum dynamic *** laser irradiation,graphite undergoes an interlayer compression and sliding stage,followed by a key period of intralayer buckling and interlayer bonding to form an intermediate sp^(2)-sp^(3) hybrid structure,before completing the full transformation to hexagonal *** process is driven by the cooperation of charge carrier multiplication and selective phonon excitations through electron-phonon interactions,in which photoexcited hot electrons scattered into unoccupied high-energy conduction bands play a key role in the introduction of in-plane instability in *** work identifies a photoinduced non-adiabatic transition pathway from graphite to diamond and shows far-reaching implications for designing optically controlled structural phase transition in materials.

关键词： structural phonon interlayer

Quantitative Electron Tomography for Accurate Measurement of Precipitates Microstructure Parameters in Al–Cu–Li Alloys

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2022年第11期35卷 1882-1894页

作者： Shi-Yong Li Ruo-Han Shen Yu-Tao He cui-Lan Wu Jiang-Hua Chen Centre for High Resolution Electron Microscopy College of Materials Science and EngineeringHunan UniversityChangsha 410082China College of Materials Science and Engineering Hainan UniversityHaikou 570228China

Mechanical theories show that properties of alloys are strongly dependent on the morphological parameters oftheir strengthening ***,accurate measurement of precipitates microstructure parameters is still a challenging *** this article,we develop a quantitative electron tomography method by combining computer vision technology to accurately characterize the three-dimensional microstructure parameters,such as volume fractions,sizes and distributions,of the T_(1) and δ’/θ’/δ’ precipitates in Al-Cu-Li(-Mg) *** they have extremely large aspect-ratios in shape and large numbers in density upon formation in the Al matrix,these thin plate-like precipitates are difficult to be characterized quantitatively without the assistance of computer vision *** is shown that the property difference between two peak-aged states of the alloy can be well explained with the quantitative precipitate parameters correctly *** these correct precipitate data,we also tested the validity of current mechanical models for projecting the contribution of precipitates to the strengths of the alloy,demonstrating that quantitative relations between strength and micro structure parameters still need to be refined.

关键词： Al–Cu–Li–Mg alloy T1 precipitate δ′/θ′/δ′composite precipitate Morphological parameters Electron tomography Computer vision

RESEARCH ON EMC OF INVERTER WELDER AND WELDING ARC 3

在线全文

学校读者我要写书评

暂无评论

RESEARCH ON EMC OF INVERTER WELDER AND WELDING ARC