期刊文献+
共找到41篇文章
< 1 2 3 >
每页显示 20 50 100
Application of Self-propelled Boom Sprayers for Control of Rice Insects and Diseases 被引量:1
1
作者 龚艳 于林惠 +3 位作者 张晓 王果 陈伟 陈晓 《Agricultural Science & Technology》 CAS 2016年第7期1667-1670,共4页
Comparisons were performed between self-propelled boom sprayer and traditional mechanis, such as knapsack sprayer and sprayer-duster, stretcher-type powered sprayer, as well as single rotor unmanned sprayer and multi-... Comparisons were performed between self-propelled boom sprayer and traditional mechanis, such as knapsack sprayer and sprayer-duster, stretcher-type powered sprayer, as well as single rotor unmanned sprayer and multi-rotor un- manned sprayer. The effects on rice injury, lodging, and rehabilitation were conclud- ed and drug uniform distribution, sedimentation and prevention effects were ana- lyzed. The results showed that the self-propelled boom sprayer is characterized by high degree of automation, convenient operation, high adaptability, and high work efficiency. What's more, the sprayed fog quality is better, and fog distribution is more uniform. During the work process, fog loss would be diminished substantially, improving work efficiency and cutting down drug and water. It is notable that the underpart of the sprayer can be widely applied to plant protection in large-scale ar- eas in Jiangsu Province, significantly advancing whole-process mechanization of rice production. 展开更多
关键词 RICE SELF-PROPELLED SPRAYERS Insect and disease control Deposition distribution
下载PDF
Pilot Study of Molecular Mechanism on Vasculogenic Mimicry in Bi-directional Differentiated Malignant Tumors 被引量:2
2
作者 孙保存 张诗武 +2 位作者 赵秀兰 张丹芳 郝希山 《The Chinese-German Journal of Clinical Oncology》 CAS 2005年第1期50-52,68,共4页
Objective: To investigate the role of collagen IV and PAS positive substancesecreted by tumor cells in vasculogenic mimicry (VM) and the effects of VM on tumor cells expressingVEGF. Methods: 158 cases of bi-direction ... Objective: To investigate the role of collagen IV and PAS positive substancesecreted by tumor cells in vasculogenic mimicry (VM) and the effects of VM on tumor cells expressingVEGF. Methods: 158 cases of bi-direction differential malignant tumor specimens withparaffin-embedded were enrolled into our study and made tissue microarray which were dual-stainedwith CD31-PAS and stained with collagen IV. The difference of the areas and distribution withpattern surrounded by between CD31 and PAS positive respectively were identified via grid-counting,as well as the difference of VEGF expression with VE absent and present. Results: The basementmembrane of VM was both PAS and collagen IV positive. VEGF expression in the bi-directiondifferential malignant tumor was higher VM-absent than VM-present and the difference wasstatistically significance in malignant melanoma and alveolar rhabdomyosarcoma (P 【 0.05).Conclusion: PAS positive substance and collagen IV compose the wall of VE and VE could provide theoxygen and nutrition for tumor growth and progression. 展开更多
关键词 bi-direction differential malignant tumor vasculogenic mimicry dual-staining tissue microarray
下载PDF
Cracked elastic substrate strip with functionally graded coating under thermal-mechanical loading
3
作者 苗福生 刘俊俏 李星 《Journal of Southeast University(English Edition)》 EI CAS 2012年第4期451-456,共6页
This paper investigates the functionally graded coating bonded to an elastic strip with a crack under thermal- mechanical loading. Considering some new boundary conditions, it is assumed that the temperature drop acro... This paper investigates the functionally graded coating bonded to an elastic strip with a crack under thermal- mechanical loading. Considering some new boundary conditions, it is assumed that the temperature drop across the crack surface is the result of the thermal conductivity index which controls heat conduction through the crack region. By the Fourier transforms, the thermal-elastic mixed boundary value problems are reduced to a system of singular integral equations which can be approximately solved by applying the Chebyshev polynomials. The numerical computation methods for the temperature, the displacement field and the thermal stress intensity factors (TSIFs) are presented. The normal temperature distributions (NTD) with different parameters along the crack surface are analyzed by numerical examples. The influence of the crack position and the thermal-elastic non- homogeneous parameters on the TSIFs of modes I and 11 at the crack tip is presented. Results show that the variation of the thickness of the graded coating has a significant effect on the temperature jump across the crack surfaces when keeping the thickness of the substrate constant, and the thickness of functionally graded material (FGM) coating has a significant effect on the crack in the substrate. The results can be expected to be used for the purpose of gaining better understanding of the thermal-mechanical behavior of graded coatings. 展开更多
关键词 thermal-mechanical loading singular integral equations functionally graded coating thermal stress intensity factors (TSIFs)
下载PDF
Memory Function and Fractional Intergral Associated to the Random Self-similar Fractal 被引量:1
4
作者 LIANG Hong-liang,LIU Xiao-shu(Department of Mathematics, Shangqiu Teacher’s College, Shangqiu 476000, China) 《Chinese Quarterly Journal of Mathematics》 CSCD 2003年第2期186-191,共6页
For a physics system which exhibits memory,if memory is preserved only at points of random self-similar fractals,we define random memory functions and give the connection between the expectation of flux and the fracti... For a physics system which exhibits memory,if memory is preserved only at points of random self-similar fractals,we define random memory functions and give the connection between the expectation of flux and the fractional integral.In particular,when memory sets degenerate to Cantor type fractals or non-random self-similar fractals our results coincide with that of Nigmatullin and Ren et al. 展开更多
关键词 random self-similar fractals memory functions memory measures Laplace transform
下载PDF
Vector control of induction motor based on fractional-order intelligent-integral speed controller 被引量:2
5
作者 MIAO Zhong-cui HAN Tian-liang +1 位作者 DANG Jian-wu JU Mei 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2018年第2期125-133,共9页
To improve dynamic and static performances and robustness of the induction motor speed control system based on vector control,an improved fractional-order intelligent proportional integral(IPIλ)controller was applied... To improve dynamic and static performances and robustness of the induction motor speed control system based on vector control,an improved fractional-order intelligent proportional integral(IPIλ)controller was applied to the speed controller of the vector control system,which combined the intelligent fractional integral with the proportion according to the variation of deviation.Compared with proportional integral(PI)and fractional-order proportional integral(FOPI)controllers,the IPIλcontroller achieved better control performance.The stimulation results indicate that the IPIλcontroller can not only track the given speed quickly and accurately,but also have better anti-interference and robustness for load and parameters variations. 展开更多
关键词 fractional-order intelligent-integral induction motor speed controller
下载PDF
Improved control of intelligent excavator using proportional-integral-plus gain scheduling 被引量:5
6
作者 顾军 D. SEWARD 《Journal of Central South University》 SCIE EI CAS 2012年第2期384-392,共9页
Consider the design and implementation of an electro-hydraulic control system for a robotic excavator, namely the Lancaster University computerized and intelligent excavator (LUCIE). The excavator was developed to aut... Consider the design and implementation of an electro-hydraulic control system for a robotic excavator, namely the Lancaster University computerized and intelligent excavator (LUCIE). The excavator was developed to autonomously dig trenches without human intervention. One stumbling block is the achievement of adequate, accurate, quick and smooth movement under automatic control, which is difficult for traditional control algorithm, e.g. PI/PID. A gain scheduling design, based on the true digital proportional-integral-plus (PIP) control methodology, was utilized to regulate the nonlinear joint dynamics. Simulation and initial field tests both demonstrated the feasibility and robustness of proposed technique to the uncertainties of parameters, time delay and load disturbances, with the excavator arm directed along specified trajectories in a smooth, fast and accurate manner. The tracking error magnitudes for oblique straight line and horizontal straight line are less than 20 mm and 50 mm, respectively, while the velocity reaches 9 m/min. 展开更多
关键词 robotic excavator gain scheduling control proportional-integral-plus ROBUSTNESS
下载PDF
Forming mechanism of integral serrated high fins by plowing-extruding based on variational feed 被引量:4
7
作者 万珍平 燕辉 汤勇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第3期400-404,共5页
Plowing-extruding tool was designed and plowing-extruding process was investigated.Then,a manufacturing method of integral serrated high-finned tube,plowing-extruding based on variational feed was proposed,in which pl... Plowing-extruding tool was designed and plowing-extruding process was investigated.Then,a manufacturing method of integral serrated high-finned tube,plowing-extruding based on variational feed was proposed,in which plowing-extruding tool moved forward at two different feeds,f1 and f2,in turn.In this method,overlaps that are usually avoided in practical application were utilized to manufacture high fins and average height of fins was up to 1.58 mm.The critical feed(fc) of overlaps forming and terms of high fins forming were analyzed.The main technical parameters that affect the fins height were discussed.The experimental results show that the fins height increases with extruding inclination angle and plowing-extruding depth,and the fins height increases with f1 increasing when f1 is smaller than fc,and decreases with f1 increasing if f1 is larger than fc. 展开更多
关键词 enhanced heat transfer tube integral serrated high fins plowing-extruding
下载PDF
Image segmentation based on Mumford-Shah functional 被引量:5
8
作者 陈旭锋 管志成 《Journal of Zhejiang University Science》 CSCD 2004年第1期123-128,共6页
In this paper, the authors propose a new model for active contours segmentation in a given image, based on Mumford-Shah functional (Mumford and Shah, 1989). The model is composed of a system of differential and integr... In this paper, the authors propose a new model for active contours segmentation in a given image, based on Mumford-Shah functional (Mumford and Shah, 1989). The model is composed of a system of differential and integral equations. By the experimental results we can keep the advantages of Chan and Vese's model (Chan and Vese, 2001 ) and avoid the regularization for Dirac function. More importantly, in theory we prove that the system has a unique viscosity solution. 展开更多
关键词 Image segmentational Mumford Shah functional Viscosity solution Level set method
下载PDF
Integrating Factors and Conservation Laws for Relativistic Mechanical System 被引量:4
9
作者 ZHANG Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2X期231-234,共4页
In this paper, we present a new method to construct the conservation laws for relativistic mechanical systems by finding corresponding integrating factors. First, the Lagrange equations of relativistic mechanical syst... In this paper, we present a new method to construct the conservation laws for relativistic mechanical systems by finding corresponding integrating factors. First, the Lagrange equations of relativistic mechanical systems are established, and the definition of integrating factors of the systems is given; second, the necessary conditions for the existence of conserved quantities of the relativistic mechanical systems are studied in detail, and the relation between the conservation laws and the integrating factors of the systems is obtained and the generalized Killing equations for the determination of the integrating factors are given; finally, the conservation theorem and its inverse for the systems are established, and an example is given to illustrate the application of the results. 展开更多
关键词 RELATIVITY mechanical system conservation law integrating factor Killing equation
下载PDF
European Option Pricing under a Class of Fractional Market 被引量:4
10
作者 费为银 《Journal of Donghua University(English Edition)》 EI CAS 2010年第6期732-737,共6页
In order to price European contingent claim in a class of fractional Black-Scholes market, where the prices of assets follow a Wick-Ito stochastic differential equation driven by the fractional Brownian motion and mar... In order to price European contingent claim in a class of fractional Black-Scholes market, where the prices of assets follow a Wick-Ito stochastic differential equation driven by the fractional Brownian motion and market coefficients are deterministic functions, the pricing formula of European call option was explicitly derived by the method of the stochastic calculus of tile fractional Brownian motion. A result about fractional Clark derivative was also obtained. 展开更多
关键词 fractional Brownian motion Wick-Ito stochasticintegral fractional It( formula ~ Girsanov thoerem forfractional Brownian motion fractional Clark-Oconetheorem option pricing
下载PDF
Optimization of press bend forming path of aircraft integral panel 被引量:6
11
作者 阎昱 万敏 +1 位作者 王海波 黄霖 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第2期294-301,共8页
In order to design the press bend forming path of aircraft integral panels,a novel optimization method was proposed, which integrates FEM equivalent model based on previous study,the artificial neural network response... In order to design the press bend forming path of aircraft integral panels,a novel optimization method was proposed, which integrates FEM equivalent model based on previous study,the artificial neural network response surface,and the genetic algorithm.First,a multi-step press bend forming FEM equivalent model was established,with which the FEM experiments designed with Taguchi method were performed.Then,the BP neural network response surface was developed with the sample data from the FEM experiments.Furthermore,genetic algorithm was applied with the neural network response surface as the objective function. Finally,verification was carried out on a simple curvature grid-type stiffened panel.The forming error of the panel formed with the optimal path is only 0.098 39 and the calculating efficiency has been improved by 77%.Therefore,this novel optimization method is quite efficient and indispensable for the press bend forming path designing. 展开更多
关键词 aircraft integral panel press bend forming path neural network response surface genetic algorithm optimization
下载PDF
The experimental study on combustion characteristics and emissions of a CMM fueled engine
12
作者 张欣 Li Congxin Xu Jian 《High Technology Letters》 EI CAS 2011年第2期202-206,共5页
In this paper, an experimental study on combustion characteristics and emissions of a single cylinder spark ignition engine fueled with coal-mine methane (CMM) is investigated under various loads. CMM is simulated b... In this paper, an experimental study on combustion characteristics and emissions of a single cylinder spark ignition engine fueled with coal-mine methane (CMM) is investigated under various loads. CMM is simulated by the compressed nature gas( CNG)/nitrogen blend fuels. Based on experiment results, it is shown that under 0% - 35% nitrogen volume fraction in CNG/nitrogen blends, the maximum cylinder pressure, the maximum rate of pressure rise and the rate of heat release decrease, the flame propagation period increases, the center of heat release curve is closed to the top dead centre (TDC)markedly with the increase of nitrogen volume fraction. Meanwhile, the hydrocarbon (HC), CO emissions increase, the NOx emission decreases apparently with the increase of nitrogen volume fraction. 展开更多
关键词 coal-mine methane(CMM) ENGINE combustion characteristic EMISSION
下载PDF
Decomposition of algal lipids in clay-enriched marine sediment under oxic and anoxic conditions
13
作者 吕冬伟 宋茜 王旭晨 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第1期131-143,共13页
A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions. During the 245-day incubation period... A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions. During the 245-day incubation period, changes in the concentrations of TOC, major algal fatty acid components (14:0, 16:0, 16:1, 18:1 and 20:5), and n-alkanes (C16-C23) were quantified in the samples. Our results indicate that the organic matters were degraded more rapidly in oxic than anoxic conditions. Adsorption of fatty acids onto clay minerals was a rapid and reversible process. Using a simple G model, we calculated the decomposition rate constants for TOC, n-alkanes and fatty acids which ranged from 0.017-0.024 d^-1, 0.049-0.103 d^-1 and 0.011 to 0.069 d-l, respectively. Algal organic matter degraded in two stages characterized by a fast and a slow degradation processes. The addition of clay minerals montmorillonite and kaolinite to the sediments showed significant influence affecting the decomposition processes of algal TOC and fatty acids by adsorption and incorporation of the compounds with clay particles. Adsorption/association of fatty acids by clay minerals was rapid but appeared to be a slow reversible process. In addition to the sediment redox and clay influence, the structure of the compounds also played important roles in affecting their degradation dynamic in sediments. 展开更多
关键词 algal organic matter DECOMPOSITION marine sediments clay minerals
下载PDF
The Burial of Biogenic Silica, Organic Carbon and Organic Nitrogen in the Sediments of the East China Sea 被引量:2
14
作者 WANG Lisha ZHANG Chuansong SHI Xiaoyong 《Journal of Ocean University of China》 SCIE CAS 2015年第3期464-470,共7页
We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic matters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribution we found the... We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic matters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribution we found the contents of these substances to be in the ranges of 0.72%-1.64%, 0.043%-0.82%, and 0.006%-0.11%, respectively. Their distributions were similar to each other, being high inside the Hangzhou Bay and low outside the bay. The vertical variations of the contents were also similar. In order to discuss the relation between them we analysed the variations of content with depth. They increased in the first 7 cm and then decreased with depth. The peaks were found at depths between 20 to 25 cm. The distribution of carbonate showed an opposite trend to that of biogenic matters. The content of total carbon was relatively stable with respect to depth, and the ratio of high organic carbon to carbonate showed a low burial efficiency of carbonate, which means that the main burial of carbon is organic carbon. In order to discuss the source of organic matters, the ratio of organic carbon to organic nitrogen was calculated, which was 8.01 to 9.65, indicating that the organic matter in the sediments was derived mainly from phytoplankton in the seawater. 展开更多
关键词 BURIAL sediment biogenic matters carbon and nitrogen ratio East China Sea
下载PDF
A large-range convergence iterative method for solving a nonlinear functional equation
15
作者 母丽华 沈继红 杜红 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第5期631-634,共4页
The existence and representation of the exact solution are given for a nonlinear functional equation in the reproducing kernel space. For a numerical computation, we present a large-range convergence iterative method ... The existence and representation of the exact solution are given for a nonlinear functional equation in the reproducing kernel space. For a numerical computation, we present a large-range convergence iterative method for solving the nonlinear functional equation. In the iterative method, the convergent condition is simple and the convergence is irrespective to the choice of the initial function. It is worthy to note that the presented method can be generalized to solve other nonlinear operator equations. 展开更多
关键词 nonlinear functional equation nonlinear Voherra integral equation reproducing kernel
下载PDF
An Improved Proportional Integral Estimator of the Stator Resistance for a Direct Torque Controlled Induction Motor
16
作者 Keltoum Benlarbi Lakhdar Mokrani Leila Mokhnache 《Journal of Energy and Power Engineering》 2013年第11期2144-2154,共11页
In this paper, an improved PI (proportional integral) stator resistance estimation for a DTC (direct torque controlled) induction motor is proposed. This estimation method is based on an on-line stator resistance ... In this paper, an improved PI (proportional integral) stator resistance estimation for a DTC (direct torque controlled) induction motor is proposed. This estimation method is based on an on-line stator resistance correction regarding the variations of the stator current estimation error. In fact, the input variable of the P1 estimator is the stator current estimation error. The main idea is to tune accurately the stator resistance value relatively to the evolution of the stator current estimation error gradient to avoid the drive instability and ensure the tracking of the actual value of the stator resistance. But there is an unavoidable steady state error between the filtered stator current modulus and its estimated value from the dq model of the machine which is due to pseudo random commutations of the inverter switches. This may deteriorate the performance of the proposed fuzzy stator resistance estimator. An offset has been introduced in order to overcome this problem, for different speed command values and load torques. Simulation results show that the proposed estimator was able to successfully track the actual value of the stator resistance lbr different operating conditions. 展开更多
关键词 Direct torque control PI estimator stator resistance tuning PWM inverter offset compensation.
下载PDF
Iterative sliding mode control strategy of robotic arm based on fractional calculus
17
作者 ZHANG Xin LU Wenru +2 位作者 MIAO Zhongcui JIANG Ziyun ZHANG Jing 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2021年第2期208-217,共10页
In order to improve the control performance of industrial robotic arms,an efficient fractional-order iterative sliding mode control method is proposed by combining fractional calculus theory with iterative learning co... In order to improve the control performance of industrial robotic arms,an efficient fractional-order iterative sliding mode control method is proposed by combining fractional calculus theory with iterative learning control and sliding mode control.In the design process of the controller,fractional approaching law and fractional sliding mode control theories are used to introduce fractional calculus into iterative sliding mode control,and Lyapunov theory is used to analyze the system stability.Then taking a two-joint robotic arm as an example,the proposed control strategy is verified by MATLAB simulation.The simulation experiments show that the fractional-order iterative sliding mode control strategy can effectively improve the tracking speed and tracking accuracy of the joint,reduce the tracking error,have strong robustness and effectively suppress the chattering phenomenon of sliding mode control. 展开更多
关键词 robotic arm fractional calculus iterative learning control sliding mode control
下载PDF
Path Planning of Planar Kinked Line Seam by Visual Servoing for Robotic Welding
18
作者 周律 林涛 陈善本 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第3期328-332,共5页
Welding path planning can substitute for the manual teaching process of the robot and can promote the autonomous level of the robotic welding. A path planning method by visual servoing was presented, in which the opti... Welding path planning can substitute for the manual teaching process of the robot and can promote the autonomous level of the robotic welding. A path planning method by visual servoing was presented, in which the optimal angle of charge-coupled device (CCD) camera was also planned. Aiming at planning two forms of kinked line seams, obtuse angle seam and right angle seam, a practicable solution was put forward. In this solution, the intersection of two adjacent straight segments is detected in each local seam image, and if intersection is found, the seam errors are calculated using the next straight segment. The experimental results show that kinked line seam can be well planned using this solution. 展开更多
关键词 robotic welding path planning visual servoing kinked line
下载PDF
Fuzzy Logic Controlled Induction Motor Based Intelligent Controller
19
作者 Salim Mahdab Linda Barazane Seghir Boucherit 《Journal of Energy and Power Engineering》 2013年第6期1192-1197,共6页
The indirect vector controlled IM (induction motor) drive involves decoupling of the stator current into torque and flux producing components. This paper proposes the implementation of a fuzzy logic control scheme a... The indirect vector controlled IM (induction motor) drive involves decoupling of the stator current into torque and flux producing components. This paper proposes the implementation of a fuzzy logic control scheme applied to a two d-q current components model of an induction motor. An intelligent based on fuzzy logic controller is developed with the help of knowledge rule base for efficient control. The performance of fuzzy logic controller is compared with that of the proportional integral controller in terms of the settling time and dynamic response to sudden load changes. The harmonic pattern of the output current is evaluated for both fixed gain proportional integral controller and the fuzzy logic based controller. The performance of the IM drive has been analyzed under steady state and transient conditions. Simulation results of both the controllers are presented for comparison. 展开更多
关键词 IVC (indirect vector control) PI controller FLC (fuzzy logic controller).
下载PDF
Existence of almost periodic solutions to a class of non- autonomous functional integro-differential stochastic equations
20
作者 Lijie Li Yu Feng Weiquan Pan 《International Journal of Technology Management》 2013年第3期46-49,共4页
In this paper, a class of non-autonomous functional integro-differential stochastic equations in a real separable Hilbert space is studied. When the operators A(t) satisfy Acquistapace-Terreni conditions, and with s... In this paper, a class of non-autonomous functional integro-differential stochastic equations in a real separable Hilbert space is studied. When the operators A(t) satisfy Acquistapace-Terreni conditions, and with some suitable assumptions, the existence and uniqueness of a square-mean almost periodic mild solution to the equations are obtained. 展开更多
关键词 Stochastic differential equations Square-mean almost periodic mild solution Acquistapace-Terreni conditions
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部