期刊文献+
共找到4,887篇文章
< 1 2 245 >
每页显示 20 50 100
Developing a highly scalable synthetic strategy for 5-amino-4-nitrobenzo[1,2-c:3,4-c']bis([1,2,5]oxadiazole)1,b-dioxide(CL-18)and investigating the influence of crystal engineering and positional isomerization on its safety and laser ignition performance
1
作者 Lei Yang Zhenqi Zhang +2 位作者 Wei Du Jinshan Li Qing Ma 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第11期13-21,共9页
5-amino-4-nitrobenzo[1,2-c:3,4-c']bis([1,2,5]oxadiazole)1,6-dioxide(CL-18)exhibits significant potential as an initiating explosive.However,its current synthesis process remains non-scalable due to low yields and ... 5-amino-4-nitrobenzo[1,2-c:3,4-c']bis([1,2,5]oxadiazole)1,6-dioxide(CL-18)exhibits significant potential as an initiating explosive.However,its current synthesis process remains non-scalable due to low yields and safety risks.In this study,we have developed a simple and safe synthetic route for CL-18.It was synthesized from 3,5-dihaloanisole in a four-step reaction with an overall yield exceeding 60%,surpassing all reported yields in the literature.Subsequently,recrystallization of CL-18 was successfully achieved by carefully selecting appropriate solvents and antisolvents to reduce its mechanical sensitivity.Ultimately,when DMF-ethanol was employed as the recrystallization solvent system,satisfactory product yield(>90%)and reduced mechanical sensitivity(IS=15 J;FS=216 N)were obtained.Additionally,CL-18 is derived from the rearrangement of oxygen atoms on i-CL-18 furoxan,and a comparative analysis of their physicochemical properties was conducted.The thermal stability of both compounds is similar,with onset decomposition temperatures recorded at 186 and 182℃respectively.Similarly,they exhibit 5 s breaking point temperatures of 236 and 237℃.Additionally,we present novel insights into the positional-isomerization-laser-ignition performance of CL-18 and its isomer i-CL-18 using laser irradiation for the first time.Remarkably,our findings demonstrate that i-CL-18 exhibits enhanced laser sensitivity,as it can be directly ignited by a 1064 nm wavelength laser,whereas CL-18 lacks this characteristic. 展开更多
关键词 Initiating explosive Synthetic method Crystal engineering positional isomerization Laser ignition
下载PDF
Estimation of Aqueous Solubility (-lgS_w) of All Polychlorinated Biphenyl (PCB) Congeners by Density Functional Theory and Position of Cl Substitution (NPCS) Method 被引量:3
2
作者 WEI Xiao-Yan GE Zhi-Gang WANG Zun-Yao XU Jiao 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第5期519-528,共10页
Optimization calculations of 209 polychlorinated biphenyls (PCBs) were carried out at the B3LYP/6-31G^* level. It was found that there is significant correlation between the Cl substitution position and some struct... Optimization calculations of 209 polychlorinated biphenyls (PCBs) were carried out at the B3LYP/6-31G^* level. It was found that there is significant correlation between the Cl substitution position and some structural parameters. Consequently, Cl substitution positions were taken as theoretical descriptors to establish a novel QSPR model for predicting –lgSw of all PCB congeners. The model achieved in this work contains four variables, of which r^2 = 0.9527, q^2 = 0.9490 and SD = 0.25 with large t values. In addition, the variation inflation factors (VIFs) of variables in this model are all less than 5.0, suggesting high accuracy of the –lgSw predicting model. And the results of cross-validation test and method validation also show that the model exhibits optimum stability and better predictive capability than that from the AM1 method. 展开更多
关键词 polychlorinated biphenyls (PCBs) aqueous solubility (-lgSw) quantitativestructure-property relationship (QSPR) position of Cl substitution (NPCS) method
下载PDF
Cone beam computed tomography-guided differences among registration methods for lung cancer and the effects of tumor position,treatment model,and tumor size on positioning errors 被引量:1
3
作者 Jiayu Du Jie Tang +1 位作者 Qian Zhang Xiaojie Ma 《Oncology and Translational Medicine》 CAS 2021年第5期203-208,共6页
Objective To explore the differences in three different registration methods of cone beam computed tomography(CBCT)-guided down-regulated intense radiation therapy for lung cancer as well as the effects of tumor locat... Objective To explore the differences in three different registration methods of cone beam computed tomography(CBCT)-guided down-regulated intense radiation therapy for lung cancer as well as the effects of tumor location,treatment mode,and tumor size on registration.Methods This retrospective analysis included 80 lung cancer patients undergoing radiotherapy in our hospital from November 2017 to October 2019 and compared automatic bone registration,automatic grayscale(t+r)registration,and automatic grayscale(t)positioning error on the X-,Y-,and Z-axes under three types of registration methods.The patients were also grouped according to tumor position,treatment mode,and tumor size to compare positioning errors.Results On the X-,Y-,and Z-axes,automatic grayscale(t+r)and automatic grayscale(t)registration showed a better trend.Analysis of the different treatment modes showed differences in the three registration methods;however,these were not statistically significant.Analysis according to tumor sizes showed significant differences between the three registration methods(P<0.05).Analysis according to tumor positions showed differences in the X-and Y-axes that were not significant(P>0.05),while the autopsy registration in the Z-axis showed the largest difference in the mediastinal and hilar lymph nodes(P<0.05).Conclusion The treatment mode was not the main factor affecting registration error in lung cancer.Three registration methods are available for tumors in the upper and lower lungs measuring<3 cm;among these,automatic gray registration is recommended,while any gray registration method is recommended for tumors located in the mediastinal hilar site measuring<3 cm and in the upper and lower lungs≥3 cm. 展开更多
关键词 lung cancer IMRT positioning error registration method CBCT different tumor locations different treatment modes tumor size
下载PDF
Two Generic Frameworks of Multiple Viewpoints Oriented Requirements Method and Their Comparison
4
作者 Song Qiang, He Yan xiang, Huang Qian School of Computer Science, State Key Laboratory of Software Engineering, Wuhan University, Wuhan 430072, China 《Wuhan University Journal of Natural Sciences》 CAS 2001年第Z1期313-319,共7页
Traditional requirements method has some problems when it is used for large distributed systems. Multiple viewpoints oriented requirements method (MVORM) is a new method for resolving these problems. This paper develo... Traditional requirements method has some problems when it is used for large distributed systems. Multiple viewpoints oriented requirements method (MVORM) is a new method for resolving these problems. This paper develops two generic formal frameworks of MVORM, framework based on refinement relation (FBRR) and framework based on implementation relation (FBIR). They are generic, because no assumptions are made about the development process or the formal description languages to be used. Three kinds of specification relations and three kinds of specification transformations are discussed over FBIR and FBRR. This paper also compares the equivalence between FBIR and FBRR. We point out that an equivalent FBIR can be found for any FBRR, but reverse transformation is not always possible. We think FBIR is better than FBRR on most cases. 展开更多
关键词 multiple viewpoints oriented requirements method framework based on refinement relation framework based on implementation relation refinement relation implementation relation
下载PDF
DFT and Position of Cl Substitution (PCS) Methods Studies on n-Octanol/water Partition Coefficients (lgK_(ow)) and Aqueous Solubility (–lgS_w) of All PCDD Congeners 被引量:5
5
作者 谢亚杰 赵惠明 +1 位作者 王遵尧 张雅荣 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第12期1409-1418,共10页
Optimized calculations of 75 PCDDs and their parent DD were carded out at the B3LYP/6-31G* level by density functional theory (DFT) method. The structural parameters were obtained and significant correlation betwee... Optimized calculations of 75 PCDDs and their parent DD were carded out at the B3LYP/6-31G* level by density functional theory (DFT) method. The structural parameters were obtained and significant correlation between the C1 substitution position and some structural parameters was found. Consequently, the number of C1 substitution positions was taken as theoretical descriptors to establish two novel QSPR models for predicting lgKow and -lgSw of all PCDD congeners. The two models achieved in this work contain two variables (Na and Nβ), of which r = 0.9312, 0.9965 and SD = 0.27, 0.12 respectively, and t values are all large. The variation inflation factors (VIF) of variables in the two models herein are both less than 5.0, suggesting high accuracy of the lgKow and -lgSw predicting models, and the results of cross-validation test also show that the two models exhibit optimum stability and good predictive power. By comparison, the correlation and predictive ability of the present work are more advantageous than those obtained using semi-empirical AM1 and GC-RI methods. 展开更多
关键词 polychlorinated dibenzo-p-dioxins (PCDDs) n-octanol/water partition coefficients(lgKow) aqueous solubility (-lgSw) quantitative structure-property relationship (QSPR) DFT position of CI substitution (PCS) method
下载PDF
A Precision-Positioning Method for a High-Acceleration Low-Load Mechanism Based on Optimal Spatial and Temporal Distribution of Inertial Energy 被引量:5
6
作者 Xin Chen Youdun Bai +2 位作者 Zhijun Yang Jian Gao Gongfa Chen 《Engineering》 SCIE EI 2015年第3期391-398,共8页
High-speed and precision positioning are fundamental requirements for high-acceleration low-load mechanisms in integrated circuit (IC) packaging equipment. In this paper, we derive the transient nonlinear dynamicres... High-speed and precision positioning are fundamental requirements for high-acceleration low-load mechanisms in integrated circuit (IC) packaging equipment. In this paper, we derive the transient nonlinear dynamicresponse equations of high-acceleration mechanisms, which reveal that stiffness, frequency, damping, and driving frequency are the primary factors. Therefore, we propose a new structural optimization and velocity-planning method for the precision positioning of a high-acceleration mechanism based on optimal spatial and temporal distribution of inertial energy. For structural optimization, we first reviewed the commonly flexible multibody dynamic optimization using equivalent static loads method (ESLM), and then we selected the modified ESLM for optimal spatial distribution of inertial energy; hence, not only the stiffness but also the inertia and frequency of the real modal shapes are considered. For velocity planning, we developed a new velocity-planning method based on nonlinear dynamic-response optimization with varying motion conditions. Our method was verified on a high-acceleration die bonder. The amplitude of residual vibration could be decreased by more than 20% via structural optimization and the positioning time could be reduced by more than 40% via asymmetric variable velocity planning. This method provides an effective theoretical support for the precision positioning of high-acceleration low-load mechanisms. 展开更多
关键词 high-acceleration low-load mechanism precision positioning spatial and temporal distribution inertial energy equivalent static loads method (ESLM) velocity planning
下载PDF
On the Method of Multiplier-enlargement and Approximation of Unbounded Continuous Functions 被引量:1
7
作者 郑成德 王仁宏 《Northeastern Mathematical Journal》 CSCD 2001年第2期231-235,共5页
By combining the classical appropriate functions “1, x, x 2” with the method of multiplier enlargement, this paper establishes a theorem to approximate any unbounded continuous functions with modified positive... By combining the classical appropriate functions “1, x, x 2” with the method of multiplier enlargement, this paper establishes a theorem to approximate any unbounded continuous functions with modified positive linear operators. As an example, Hermite Fejér interpolation polynomial operators are analysed and studied, and a general conclusion is obtained. 展开更多
关键词 positive linear operator approximation of unbounded continuous function method of multiplier enlargement Hermite Fejér interpolation polynomial operator
下载PDF
Preliminary Research on the Mathematical Methods and Order of Problems in the“Fungcheng”Chapter of Yang Hui's Mathematical Methods(1261 CE) 被引量:1
8
作者 Zhou Xiaohan 《Chinese Annals of History of Science and Technology》 2020年第1期1-62,共62页
Yang Hui was one of the most important authors of mathematical works during the thirteenth century.Mathematical Methods Explaining in Detail The Nine Chapters(Xiangjie jiuzhang suanfa詳解九章算法,1261 CE)is the earlie... Yang Hui was one of the most important authors of mathematical works during the thirteenth century.Mathematical Methods Explaining in Detail The Nine Chapters(Xiangjie jiuzhang suanfa詳解九章算法,1261 CE)is the earliest extant work attributed to Yang Hui.From the thirteenth to the fifteenth century,this work played a crucial role in the circulation and popularization of The Nine Chapters on Mathematical Procedures(Jiuzhang suanshu九章算术).However,the only surviving printed edition of Mathematical Methods is incomplete and contains many mistakes obstructing contemporary researchers'understanding of this work.The "Fangcheng" chapter of The Nine Chapters deals with problems related to solving what today are known as simultaneous sets of linear equations.However,interpreting the text in this chapter of Mathematical Methods and recovering the mathematical practices relating to fangcheng are difficult.Through detailed textual and mathematical analyses,the author of this paper explains Yang Hufs understanding and practice relating to〃the fangcheng method"and"the method of the positive and the negative".This paper includes an appendix that provides a detailed translation of the ambiguous text relating to"the method of the positive and the negative"and gives reasons supporting the interpretation provided here.Yang Hufs understanding of the concepts of"positive"and"negative"and his practice relating to these two concepts may easily be confused with their apparent counterparts in modem mathematics.Also,careful analysis of the mathematical methods in this work reveal that the order of problems in Yang Hufs Reclassifications of Mathematical Methods Explaining in Detail The Nine Chapters([Xiangjie jiuzhang suanfa zuanlei詳解九章算法纂類],namely,the last section of Mathematical Methods)were rearranged according to commentaries to specific methods that appear in Mathematical Methods.Some textual clues referring to the zzprevious question"(qianwen前問)in certain commentaries of Mathematical Methods indeed reflect the order of problems in Reclassifications.Yang Hui made especially detailed commentaries on the problems that he arranged in a sequence that differs with respect to the original order of problems as they appear in the ancient classic work,The Nine Chapters.All these discoveries reveal and serve to prove a close relationship between Yang Hufs Mathematical Methods and his Reclassifications. 展开更多
关键词 Mathematical methods Explaining in Detail the Nine Chapters Reclassifications of Mathematical methods Explaining in Detail the Nine Chapters the Nine Chapters Yang Hui the fangcheng method the method of the positive and the negative translations of ancient mathematical writing
下载PDF
The method to evaluate the position error in graphic positioning technology
9
作者 卢慧卿 王宝光 +1 位作者 刘力双 李亚标 《Chinese Optics Letters》 SCIE EI CAS CSCD 2004年第9期528-530,共3页
In the measurement of automobile body-in-white, it has been widely studied to position the twodimensional (2D) visual sensors with high precision. In this paper a graphic positioning method is proposed, a hollow tetra... In the measurement of automobile body-in-white, it has been widely studied to position the twodimensional (2D) visual sensors with high precision. In this paper a graphic positioning method is proposed, a hollow tetrahedron is used for a positioning target to replace all the edges of a standard automobile body. A 2D visual sensor can be positioned through adjusting two triangles to be superposed on a screen of the computer, so it is very important to evaluate the superposition precision of the two triangles. Several methods are discussed and the least square method is adopted at last, it makes the adjustment more easy and intuitive with high precision. 展开更多
关键词 Automobile bodies Graphic methods Laser applications Least squares approximations position measurement SENSORS Two dimensional
原文传递
Motion Regular Analysis and Its Simulation of the Rodless Drilling Unit's Guiding & Positioning Board
10
作者 胡长胜 赵伟民 马强 《Journal of Donghua University(English Edition)》 EI CAS 2009年第1期31-35,共5页
To analyze the stress of the guiding & positioning board and the effectiveness of the guiding & positioning device,according to guiding & positioning device's operational principle and structure,the gu... To analyze the stress of the guiding & positioning board and the effectiveness of the guiding & positioning device,according to guiding & positioning device's operational principle and structure,the guiding & positioning board's motion regular was analyzed by diagrammatical method based on 2 postulated conditions.Considering about the working conditions' change,simulations in 5 different kinds of working conditions were done to check the correctness of the motion regulars obtained by diagrammatical method.Simulation results prove that the motion regulars are right,the postulated conditions have no effect on the obtained motion regulars.According to the simulation results,the motion processs's characters were drawn out at the same time. 展开更多
关键词 rodless drilling uint guiding positioningdevice guiding positioning board motion regular diagrammatical method simulation test
下载PDF
Crack stop holes in steel bridge decks:Drilling method and effects 被引量:19
11
作者 FU Zhong-qiu JI Bo-hai +1 位作者 XIE Shu-hui LIU Tian-jia 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第10期2372-2381,共10页
Force analysis using a compact tension model, as recommended by ASTM, was carried out on a crack stop hole. The stress before, and after, drilling the hole was compared in terms of stress concentration and stress grad... Force analysis using a compact tension model, as recommended by ASTM, was carried out on a crack stop hole. The stress before, and after, drilling the hole was compared in terms of stress concentration and stress gradient. The optimum drilling location and diameter were studied through analysis of different locations and diameters. By analyzing the effects of flank holes and an additional hole, drilling advice was proposed and fatigue testing of the cracks in a steel bridge deck with a crack stop hole was conducted. The results show that the stress at the crack tip with a crack stop hole decreased, and the major principal stress around the hole was distributed accordingly. The optimum position of the crack stop hole centre was where the centre of the crack stop hole was situated behind the crack and the hole edge coincided with the crack tip. Therefore, hole diameters larger than 8 mm, or those weakening the section by 10%, were suggested as the best diameters. In terms of multi-hole crack stopping, a flank hole was not recommended. The optimum horizontal position of flank holes was at a distance of 1/4 of a single hole diameter from, and in front of, the single hole. Besides, the experiment showed that crack stop hole could only prevent cracks from growing and had no influence on crack growth rate. 展开更多
关键词 steel bridge DECK fatigue CRACK STOP HOLE DRILLING method HOLE position
下载PDF
GPS short-delay multipath estimation and mitigation based on least square method 被引量:6
12
作者 Zhang Shengkang~(1,2),Wang Hongbo~(1,2),Yang Jun~(1,2) & He Leiming~(1,2) 1.Beijing Inst.of Radio Metrology and Measurement,Beijing 100854,P.R.China 2.National Key Laboratory of Metrology and Calibration Technology,Beijing 100854,P.R.China 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第5期954-961,共8页
The GPS multipath signal model is presented, which indicates that the coherent DLL outputs in multipath environment are the convolution between the ideal DLL outputs and the channel responses. So the channel responses... The GPS multipath signal model is presented, which indicates that the coherent DLL outputs in multipath environment are the convolution between the ideal DLL outputs and the channel responses. So the channel responses can be estimated by a least square method using the observed curve of the DLL discriminator. In terms of the estimated multipath channels, two multipath mitigation methods are discussed, which are equalization filtering and multipath subtracting, respectively. It is shown, by computer simulation, that the least square method has a good performance in channels estimation and the multipath errors can be mitigated almost completely by either of the methods. However, the multipath subtracting method has relative small remnant errors than equalization filtering. 展开更多
关键词 global positioning system short-delay least square method multipath mitigation.
下载PDF
MULTIPLICITY AND CONCENTRATION BEHAVIOUR OF POSITIVE SOLUTIONS FOR SCHRDINGER-KIRCHHOFF TYPE EQUATIONS INVOLVING THE p-LAPLACIAN IN R^N 被引量:3
13
作者 贾慧芳 李工宝 《Acta Mathematica Scientia》 SCIE CSCD 2018年第2期391-418,共28页
In this article, we study the multiplicity and concentration behavior of positive solutions for the p-Laplacian equation of SchrSdinger-Kirchhoff type -εpM(εp-N∫RN|△u|p)△pu+v(x|u|p-2u=f(u)in RN, where ... In this article, we study the multiplicity and concentration behavior of positive solutions for the p-Laplacian equation of SchrSdinger-Kirchhoff type -εpM(εp-N∫RN|△u|p)△pu+v(x|u|p-2u=f(u)in RN, where △p is the p-Laplacian operator, 1 〈 p 〈 N, M : R+ → R+ and V : RN →R+ are continuous functions, ε is a positive parameter, and f is a continuous function with subcritical growth. We assume that V satisfies the local condition introduced by M. del Pino and P. Felmer. By the variational methods, penalization techniques, and Lyusternik- Schnirelmann theory, we prove the existence, multiplicity, and concentration of solutions for the above equation. 展开更多
关键词 SchrSdinger-Kirchhoff type equation variational methods multiple positive solutions concentrating solution penalization method
下载PDF
Solving single-frequency phase ambiguity using parameter weights fitting and constrained equation ambiguity resolution methods 被引量:5
14
作者 阳仁贵 欧吉坤 +3 位作者 袁运斌 张克非 闻德保 Ron Grenfell 《Journal of Central South University of Technology》 EI 2006年第1期93-98,共6页
Based on the structural characteristics of the double-differenced normal equation, a new method was proposed to resolve the ambiguity float solution through a selection of parameter weights to construct an appropriate... Based on the structural characteristics of the double-differenced normal equation, a new method was proposed to resolve the ambiguity float solution through a selection of parameter weights to construct an appropriate regularized matrix, and a singular decomposition method was used to generate regularization parameters. Numerical test results suggest that the regularized ambiguity float solution is more stable and reliable than the least-squares float solution. The mean square error matrix of the new method possesses a lower correlation than the variancecovariance matrix of the least-squares estimation. The size of the ambiguity search space is reduced and the search efficiency is improved. The success rate of the integer ambiguity searching process is improved significantly when the ambiguity resolution by using constraint equation method is used to determine the correct ambiguity integervector. The ambiguity resolution by using constraint equation method requires an initial input of the ambiguity float solution candidates which are obtained from the LAMBDA method in the new method. In addition, the observation time required to fix reliable integer ambiguities can he significantly reduced. 展开更多
关键词 global position system ill-conditioned state parameter weight fitting method constraint equation integer ambiguity
下载PDF
A NOTE ON THE UNIQUENESS AND THE NON-DEGENERACY OF POSITIVE RADIAL SOLUTIONS FOR SEMILINEAR ELLIPTIC PROBLEMS AND ITS APPLICATION 被引量:1
15
作者 Shinji ADACHI Masataka SHIBATA Tatsuya WATANABE 《Acta Mathematica Scientia》 SCIE CSCD 2018年第4期1121-1142,共22页
In this paper, we are concerned with the uniqueness and the non-degeneracy of positive radial solutions for a class of semilinear elliptic equations. Using detailed ODE anal- ysis, we extend previous results to cases ... In this paper, we are concerned with the uniqueness and the non-degeneracy of positive radial solutions for a class of semilinear elliptic equations. Using detailed ODE anal- ysis, we extend previous results to cases where nonlinear terms may have sublinear growth. As an application, we obtain the uniqueness and the non-degeneracy of ground states for modified SchrSdinger equations. 展开更多
关键词 positive radial solution UNIQUENESS NON-DEGENERACY shooting method
下载PDF
Position and Velocity Time Delay for Suppression Vibrations of a Hybrid Rayleigh-Van der Pol-Duffing Oscillator 被引量:3
16
作者 Y.A.Amer A.T.El-Sayed M.N.Abd El-Salam 《Sound & Vibration》 EI 2020年第3期149-161,共13页
In this paper,we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing oscillator.This system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an ex... In this paper,we used time delay feedback to minimize the vibrations of a hybrid Rayleigh–van der Pol–Duffing oscillator.This system is a one-degree-offreedom containing the cubic and fifth nonlinear terms and an external force.We applied the multiple scales method to get the solution from first approximation.Graphically and numerically,we studied the system before and after adding time delay feedback at the primary resonance case(ffi!).We used MATLAB program to simulate the efficacy of different parameters and the time delay on the main system. 展开更多
关键词 position time delay feedback velocity time delay feedback multiple scales method resonance cases
下载PDF
Design and Implementation of Digital Fractional Order PID Controller Using Optimal Pole-Zero Approximation Method for Magnetic Levitation System 被引量:3
17
作者 Amit S.Chopade Swapnil W.Khubalkar +2 位作者 A.S.Junghare M.V.Aware Shantanu Das 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第5期977-989,共13页
The aim of this paper is to employ fractional order proportional integral derivative(FO-PID)controller and integer order PID controller to control the position of the levitated object in a magnetic levitation system(M... The aim of this paper is to employ fractional order proportional integral derivative(FO-PID)controller and integer order PID controller to control the position of the levitated object in a magnetic levitation system(MLS),which is inherently nonlinear and unstable system.The proposal is to deploy discrete optimal pole-zero approximation method for realization of digital fractional order controller.An approach of phase shaping by slope cancellation of asymptotic phase plots for zeros and poles within given bandwidth is explored.The controller parameters are tuned using dynamic particle swarm optimization(d PSO)technique.Effectiveness of the proposed control scheme is verified by simulation and experimental results.The performance of realized digital FO-PID controller has been compared with that of the integer order PID controllers.It is observed that effort required in fractional order control is smaller as compared with its integer counterpart for obtaining the same system performance. 展开更多
关键词 Approximation methods digital control dis-cretization fractional calculus fractional order PID controller(FO-PID) magnetic levitation particle swarm optimization(PSO) position control.
下载PDF
Reliability of gas holdup measurements using the differential pressure method in a cyclone-static micro-bubble flotation column 被引量:1
18
作者 Xia Wencheng Yang Jianguo Wang Yuling 《Mining Science and Technology》 EI CAS 2011年第6期797-801,共5页
Gas holdup is one of the key parameters in flotation process. Gas holdup as measured by a differential pressure method was investigated and the relative errors compared to the average gas holdup from the volume expans... Gas holdup is one of the key parameters in flotation process. Gas holdup as measured by a differential pressure method was investigated and the relative errors compared to the average gas holdup from the volume expansion method. The errors were used to establish optimum measurement positions. The results show that the measurement position should be in the middle of the column and in the region half way from the center to the wall (the half-radius). The gas holdup along the axial direction is lower at the bottom and higher at the top of the floatation column. The gas holdup along the radial direction is lower near the wall and higher near the center of the flotation column. The average gas holdup measure- ment can be replaced by regional gas holdup values. 展开更多
关键词 Gas holdup distribution Differential pressure method Measurement positions Axial direction Radial direction
下载PDF
A new modification of false position method based on homotopy analysis method
19
作者 Saeid Abbasbandy 廖世俊 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第2期223-228,共6页
A new modification of false position method for solving nonlinear equations is presented by applying homotopy analysis method (HAM). Some numerical illustrations are given to show the efficiency of algorithm.
关键词 false position method regula falsi method homotopy analysis method
下载PDF
Restraint on the Effect of Friction by Localization Method
20
作者 胡恒章 傅丽 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 1994年第2期34-36,共3页
The characterization of friction in control systems and its restraint by localization method are analyzed. The minimum velocity and position precision of control systems with friction are obtained analytically. The co... The characterization of friction in control systems and its restraint by localization method are analyzed. The minimum velocity and position precision of control systems with friction are obtained analytically. The condition of global stability is given. 展开更多
关键词 ss: LOCALIZATION method FRICTION minimum VELOCITY position precision
下载PDF
上一页 1 2 245 下一页 到第
使用帮助 返回顶部