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distributed parameters modeling for the dynamic stiffness of a spring tube in servo valves

STRUCTURAL ENGINEERING AND MECHANICS 2020年第3期75卷 327-337页

作者： Lv, Xinbei Saha, Bijan Krishna Wu, You Li, Songjing Harbin Inst Technol Dept Fluid Control & Automat Box 3040Sci Pk 2Yikuang St Harbin 150001 Heilongjiang Peoples R China

The stability and dynamic performance of a flapper-nozzle servo valve depend on several factors, such as the motion of the armature component and the deformation of the spring tube. As the only connection between the armature component and the fixed end, the spring tube plays a decisive role in the dynamic response of the entire system. Aiming at predicting the vibration characteristics of the servo valves to combine them with the control algorithm, an innovative dynamic stiffness based on a distributed parameter model (DPM) is proposed that can reflect the dynamic deformation of the spring tube and a suitable discrete method is applied according to the working condition of the spring tube. With the motion equation derived by DPM, which includes the impact of inertia, damping, and stiffness force, the mathematical model of the spring tube dynamic stiffness is established. Subsequently, a suitable program for this model is confirmed that guarantees the simulation accuracy while controlling the time consumption. Ultimately, the transient response of the spring tube is also evaluated by a finite element method (FEM). The agreement between the simulation results of the two methods shows that dynamic stiffness based on DPM is suitable for predicting the transient response of the spring tube.

关键词： servo-valve distributed parameters spring tube transient response mathematical model

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Analysis of first-order reactions with distributed parameters

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STRUCTURAL CHEMISTRY 2004年第5期15卷 461-468页

作者： Janus, K Sworakowski, J Wroclaw Univ Technol Inst Phys & Theoret Chem PL-50370 Wroclaw Poland

Simple methods of analysis of first-order kinetic processes controlled by distributions of parameters ( activation energies and/or frequency factors) are presented. Both the isothermal and nonisothermal regimes are considered. The procedures make use of numerically calculated time derivatives of the concentrations of decaying species ( reactants in the case of chemical reactions). They do not require any adjustable initial or boundary values of parameters ( like concentration at the infinite time) being thus more accurate and reliable than earlier methods in which kinetic parameters were determined from the concentration, and not from its time derivative. The methods were successfully employed in analysis of the thermally driven cis-trans isomerization of a photochromic crown ether containing the azobenzene moiety incorporated in the crown.

关键词： first-order kinetics distributed parameters azobenzene derivative photochromism

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Effects of High Frequency on the distributed parameters of the Sparse-Wound Solenoid Coils

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IEEE TRANSACTIONS ON PLASMA SCIENCE 2014年第1期42卷 154-161页

作者： Lu, Boyong Yang, Xubo Hunan Mech & Elect Polytech Changsha 410151 Hunan Peoples R China

Solenoid has broad applications in power system, power electronics, and pulsed power technology. In this paper, a dispersion method for high-frequency solenoid analysis is put forward. The proposed method can accurately calculate the distributed parameters of the solenoid coils such as self-capacitance and solenoid inductance. The most important point is that the dispersion method can accurately analyze the effects of working frequency and dielectric distribution on the distributed parameters of the high-frequency solenoid, while the traditional static magnetic method is incompetent to do this job. When the solenoid was filled with uniform dielectric, the solenoid inductance had a large monotonic decrement when the working frequency increased. However, when the solenoid was filled with discontinuous dielectrics, the working frequency and the dielectric discontinuity showed strong effects on the solenoid inductance and other distributed parameters. Experimental results demonstrated the dispersion method and its calculation results.

关键词： distributed parameters filling dielectrics helical dispersion high frequency solenoid

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Minimax optimization of stationary states in systems with distributed parameters

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JOURNAL OF COMPUTER AND SYSTEMS SCIENCES INTERNATIONAL 2013年第2期52卷 165-179页

作者： Rapoport, E. Ya Samara State Tech Univ Samara 443100 Russia

The minimization problem for deviations of the stationary state of a system with distributed parameters from a desired state estimated in the uniform metric is considered. A constructive method for its solution using a successive parameterization of controls and the alternance properties of optimal spatial distributions of the controlled variable is proposed. Examples of the use of the proposed computational scheme of the organization of computational algorithms in optimization problems of stationary thermal conductivity processes are discussed.

关键词： Optimization Stationary States distributed parameters control variable Stationary state Minimax system parameter optical coherence tomography angiography device distributed parameter

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Simulation and analysis of the effect of ungrounded rectangular loop distributed parameters on TEM response

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JOURNAL OF APPLIED GEOPHYSICS 2018年 149卷 105-113页

作者： Shi, Zongyang Liu, Lihua Xiao, Pan Geng, Zhi Liu, Fubo Fang, Guangyou Chinese Acad Sci Inst Elect Key Lab Electromagnet Radiat & Sensing Technol Beijing 100190 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

An ungrounded loop in the shallow subsurface transient electromagnetic surveys has been studied as the transmission line model for early turn-off stage, which can accurately explicate the early turn-off current waveform inconsistency along the loop. In this paper, the Gauss-Legendre numerical integration method is proposed for the first time to simulate and analyze the transient electromagnetic (TEM) response considering the different early turn-off current waveforms along the loop. During the simulation, these integral node positions along the loop are firstly determined by solving these zero points of Legendre polynomial, then the turn-off current of each node position is simulated by using the transfer function of the transmission line. Finally, the total TEM response is calculated by using the Gauss-Legendre integral formula. In addition, the comparison and analysis between the results affected by the distributed parameters and that generated by lumped parameters are presented. It is found that the TEM responses agree well with each other after current is thoroughly switched off, while the transient responses in turn-off stage are completely different. It means that the position dependence of the early turn-off current should be introduced into the forward model during the early response data interpretation of the shallow TEM detection of the ungrounded loop. Furthermore, the TEM response simulations at four geometric symmetry points are made. It shows that early responses of different geometric symmetry points are also inconsistent. The research on the influence of turn-off current position dependence on the early response of geometric symmetry point is of great significance to guide the layout of the survey lines and the transmitter location. (C) 2018 Elsevier B.V. All rights reserved.

关键词： distributed parameters Gauss-Legendre numerical integral method TEM forward modeling Turn-off current Ungrounded loop

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Location Method for Interline and Grounded Faults of Double-Circuit Transmission Lines Based on distributed parameters

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IEEE TRANSACTIONS ON POWER DELIVERY 2015年第3期30卷 1307-1316页

作者： Ma, Jing Shi, Yuxin Ma, Wei Wang, Zengping North China Elect Power Univ State Key Lab Alternate Elect Power Syst Renewabl Beijing 071003 Peoples R China Virginia Polytech Inst & State Univ Bradley Dept Elect & Comp Engn Blacksburg VA 24061 USA Shanxi Elect Power Corp Elect Power Res Inst Taiyuan 030000 Shanxi Peoples R China

This paper presents a one-terminal fault-location method for interline and grounded faults of double-circuit transmission lines considering the distributed parameter. The influence of mutual inductances is taken into account in a six-sequence network of a distributed parameter model. And the compensation voltage with the help of a co-rotating zero-sequence compensation coefficient and reverse zero-sequence compensation coefficient is defined. Then, the phase and the amplitude of fault voltage are calculated by utilizing the relationship between measured reverse sequence current and fault reverse sequence current. Then, fault-location function is constructed by utilizing the measured voltage, measured current, and estimated fault voltage. Finally, the fault location is identified by solving the phase mutation point of fault-location function. The simulation results show that the method can be widely used for interline and grounded faults without the information of other substations. In addition, this method is merely influenced by fault location, transition resistance, source impedance, and is able to locate the fault accurately and is easy to implement.

关键词： distributed parameters double-circuit transmission line fault-location function interline fault

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Extraction of distributed parameters for multi-conductor transmission lines by the difference iteration method

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The Journal of China Universities of Posts and Telecommunications 2018年第5期25卷 93-100页

作者： Yang Li Lu Guizhen School of Information Engineering Communication University of China

The distributed parameters of the transmission lines have the significant impact to the signal propagation. In the conventional method of the distributed parameter extraction,the discontinuity of inverse trigonometric or hyperbolic can arise the problem about phase ambiguity which causes significant errors for transmission models. A difference iteration method（ DIM） is proposed for extracting distributed parameters of high frequency transmission line structure in order to overcome the phase ambiguity in the conventional method（ CM）. The formulations of the proposed method are first derived for two-conductor and multi-conductor lines. Then the validation is performed for the models of micro-strip transmission line. Numerical results demonstrate that the proposed DIM can solve the problem about the phase ambiguity and the extracted distributed parameters are accurate and efficient for a wide range of the frequencies of interest and line lengths.

关键词： two-conductor transmission line multi-conductor transmission line conventional method difference iteration method distributed parameters

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Geometric and Analytic Views in Existence Theorems for Optimal Control in Banach Spaces. Part 1. distributed parameters

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JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS 1974年第5期14卷 505-520页

作者： Cesari, L. Univ Michigan Dept Math Ann Arbor MI 48109 USA

Existence theorems for optimal control problems in Banach spaces are stated and proved.

关键词： Existence theorems optimal control control theory Banach spaces distributed parameters

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Modeling of the Soybean Grains Hydration by a distributed parameters Approach

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INTERNATIONAL JOURNAL OF FOOD ENGINEERING 2009年第3期5卷 16-17页

作者： Coutinho, Monica Ronobo Omoto, Edilson Sadayuki Conceicao, Wagner Andre dos Santos Andrade, Cid Marcos Goncalves Jorge, Luiz Mario de Matos Univ Estadual Maringa Maringa Parana Brazil

A mathematical model with distributed parameters was proposed to describe the absorption of water by soybeans, in order to evaluate the moisture content variation with time inside the grains. This model was represented by a partial differential equation (second order relative to position and first order relative to time), whose parameters were numerically adjusted using a minimum squares method. For this purpose, available MATLAB routines were used, together with experimental data obtained from hydration tests where soybeans were immersed in liquid water at temperatures of 10, 20, 30, 42 and 49 degrees C. According to the results, the model was able to represent the main characteristics of the hydration process, with a maximum deviation of 10% in the whole set of experimental conditions.

关键词： hydration process modeling distributed parameters soybeans

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Stabilization of stochastic Hopfield neural network with distributed parameters

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Science in China(Series F) 2004年第6期47卷 752-762页

作者： LUOQi DENGFeiqi BAOJundong ZHAOBirong FUYuli CollegeofAutomationScienceandEngineering SouthChinaUniversityofTechnologyGuangzhou510640China//CollegeofScienceWuhanUniversityofScienceandTechnologyWuhan430081China CollegeofAutomationScienceandEngineering SouthChinaUniversityofTechnologyGuangzhou510640China CollegeofAutomationScienceandEngineering SouthChinaUniversityofTechnologyGuangzhou510640China//CollegeofMathematicScienceInnerMongoliaNormalUniversityHohhot010022China

In this paper, the stability of stochastic Hopfield neural network with distributed parameters is studied. To discuss the stability of systems, the main idea is to integrate the solution to systems in the space variable. Then, the integration is considered as the solution process of corresponding neural networks described by stochastic ordinary differential equations. A Lyapunov function is constructed and Ito formula is employed to compute the derivative of the mean Lyapunov function along the systems, with respect to the space variable. It is difficult to treat stochastic systems with distributed parameters since there is no corresponding Ito formula for this kind of system. Our method can overcome this difficulty. Till now, the research of stability and stabilization of stochastic neural networks with distributed parameters has not been considered.

关键词： Hopfield neural networks distributed parameters average exponential stability in mean square.

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