共查询到20条相似文献，搜索用时 78 毫秒
1.
n-soliton-like solutions of three non-isospectral equations, the non-isospectral mKdV equation, the non-isospectral sine-Gordon equation and the non-isospeetral nonlinear Schroedinger equation were obtained by using the Hirota method. 相似文献
2.
Stabilization for a class of second-order switched systems with saturation constrains 总被引：1，自引：0，他引：1
This paper proposes a global stabilization method for a class of planar switched systems with input saturation constrains
by using a state feedback and switching strategy. This method is proved to be effective by analyzing the characteristics of
the trajectory of second-order linear systems with input saturation.
Project supported by the China Postdoctoral Science Foundation (Grant No.20070420643), the National Natural Science Foundation
of China (Grant No.60774059), and the Innovation Program of the Shanghai Municipal Science and Technology Commission (Grant
No.08DZ2272400) 相似文献
3.
A novel asymmetrical pitch system for rotary wing is presented. The pitch control characteristics are studied and analyzed.
Because elastic linkage is a key part in whole asymmetrical pitch system, in order to obtain the variation of the elastic
linkage deformation, an experimental platform mainly based on the device of micro aerial vehicles (MAVs) and a new control
system mounted on TMS320LF2407 are designed. This control system has its compacted configuration and reliability. Finally,
using this system to control the MAV for simulating the flying forward, experimental results show the MAV’s flight attitude
can be controlled based on the variation of the elastic linkage.
Project supported by the National Natural Science Foundation of China (Grant No.60605028), the National High-Technology Research
and Development Program of China (Grant No.2007AA04Z225), the Shanghai Rising-Star Program (Grant Nos.07QA14024, 07QH14006),
the Shanghai Shuguang Program (Grant No.07SG47), and the Shanghai Leading Key Laboratory of Mechanical Automation and Robotics
Science Foundation (Grant No.ZZ0805) 相似文献
4.
This paper is concerned with a control method for an exoskeleton ankle with electromyography (EMG) signals. The EMG signals
of human ankle and the exoskeleton ankle are introduced. Then a control method is proposed to control the exoskeleton ankle
using the EMG signals. The feed-forward neural network model applied here is composed of four layers and uses the back-propagation
training algorithm. The output signals from neural network are processed by the wavelet transform. Finally the control orders
generated from the output signals are passed to the motor controller and drive the exoskeleton to move. Through experiments,
the equality of neural network prediction of ankle movement is evaluated by giving the correlation coefficient. It is shown
from the experimental results that the proposed method can accurately control the movement of ankle joint.
Project supported by the National High-Tech R&D Program (Grant No.2006AA04Z224), the Innovation Program of Shanghai Municipal
Education Commission (Grant No.08ZZ48), and the Shanghai Leading Academic Discipline Project (Grant No.Y0102) 相似文献
5.
For the non-conservative holonomic Hamiltonian systems in phase space, the definition and criteria of the form invariance of the generalized Hamilton canonical equations were given. The relations among the form invariance, Noether symmetry and Lie symmetry were studied. The theory of the form invariance for the conservative holonomical systems was worked out. An example was given to illustrate the results. 相似文献
6.
Ｚｉｒｃｏｎｉｕｍａｌｌｏｙｓｐｏｓｓｅｓｓｉｎｇｖｅｒｙｌｏｗａｂｓｏｒｐｔｉｏｎｆｏｒｔｈｅｒｍａｌｎｅｕｔｒｏｎｓ,ｇｏｏｄｃｏｒｒｏｓｉｏｎｒｅｓｉｓｔａｎｃｅｉｎｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｗａｔｅｒ ,ａｎｄｒｅａｓｏｎａｂｌｅｍｅｃｈａｎｉｃａｌｐｒｏｐ ｅｒｔｉｅｓａｒｅｉｍｐｏｒｔａｎｔｍａｔｅｒｉａｌｓｆｏｒｎｕｃｌｅａｒｉｎｄｕｓｔｒｙ ,ａｎｄｈａｖｅｂｅｅｎｅｍｐｌｏｙｅｄａｓｎｕｃｌｅａｒｆｕｅｌｃｌａｄｄｉｎｇａｎｄａｓｓｔｒｕｃｔｕｒｅｍａｔｅｒｉａｌｓｉｎｌｉｇｈｔ… 相似文献
7.
Microstructure Refinement of Sn-Sb Peritectic Alloy under High-Intensity Ultrasound Treatment 总被引：2，自引：0，他引：2
In this paper the solidification behavior of Sn-Sb peritectic alloy and the mechanism of grain refinement in solidification process under high-intensity ultrasonic field are investigated. Three different powers of high-intensity ultrasound are introduced into molten Sn-Sb peritectic alloy to study the refining effectiveness. The results show that the application of high-intensity ultrasound during solidification process of Sn-Sb peritectic alloy can refine a phase and β phase and eliminate gravity segregation of the alloy. As acoustic intensity is increased from 400 W to 800 W, not only the homogenous fine structure can be obtained, but also the cubic β phase crystals tend to be spherical. Microstructure of the sample treated by 600 W high-intensity ultrasound demonstrates the best refining effect. 相似文献
8.
Xia A-gen Ye Jian-ting Ye Quan-lin Tao Xiang-ming Jin Jin-sheng Ye Gao-xiang 《浙江大学学报(A卷英文版)》2001,2(4):379-383
A new aluminum thin film percolation system, deposited on glass and silicon wafer surfaces by a vapor deposition method, was
investigated. By using the expansive and mobile behaviors of the silicone oil, the Al films are quenched gradually by the
silicone oil during the deposition process. TheR-I behavior of the film system was studied, and the anomalous conductivity indicated that, at very low current, the hopping
and tunneling effects in the films are much stronger than those of the normal film systems.
Project supported by NSFC (Grant No. 19874016) and the Special Fund of Zhejiang Provincial Natural Science Foundation for
Young Scientists (Grant No. 1997-RC9603). 相似文献
9.
1 IntroductionItiswellknownthatfluidflowsinsealsandbear ingsturnfromlaminarregimeintoturbulentonewhentheirReynoldsnumberbecomeshigherthanacriticalvalue .Theearliesttheoriesofhydrodynamiclubricationhavebeenbasedonthepresumptionofex istenceoflaminarflowregime .Inturbulentregime ,however ,thecharacteristicsofsealsandbearingsdif ferfromthepredictionsbytheoriessobased .Speciallubricationtheoriesbasedoncontemporaryturbulencemodelssincethelaterhalfof 190 0’swerethereforedevelopedtotaketheeffectsof… 相似文献
10.
Two types of molecular and polymer devices employing (2-(4′-biphenyl)-5-(4““““““““-tert-butylphenyl)-1,3,4-oxadiazole) (PBD)and poly(N-vinylcarbazole) (PVK) as electron transport and hole transport materials, respectively, have been fabricated. The structures of these two devices are ITO/PVK( 70 nm)/PBD(60 nm)/A1 and ITO/PVK: PBD (1:1 by mass, 70 nm)/A1. The formation of exciplex is evident by comparing the electroluminescence (EL) of a bi-layer device and the photoluminescence (PL) of a PVK and PBD mixed film.The maximum emission energy of exciplex evaluated is consistent with the peak emission of EL. Blue emissions from both devices are obtained. The type of exicplex is interpreted based on the energy level diagram of the bi-layer device. 相似文献
11.
Lewis R. Goldberg 《Instructional Science》1972,1(2):153-210
The goal of this research project was to discover those personality characteristics of college students which predispose them towards learning more effectively from one, rather than some other, particular instructional format. Over 800 students in each of two college courses were taught by one of four different methods, and three broad classes of criterion information were assessed: (a) knowledge of course content, (b) amount of extra-curricular reading, and (c) degree of student satisfaction. Each student completed an extensive battery of personality measures, which yielded over 350 test scores. The ratio of significant interaction effects to the number expected by chance was only 4 to 3. Consequently, new interaction scales were developed empirically in each course, and these were then cross-validated in the other course. In general, these new scales did not produce statistically significant interaction effects upon cross-validation, and scales constructed from items which produced significant interactions in both courses showed low internal consistency and low convergent validity. Factors which could have attenuated the strength of trait-by-treatment interaction effects are discussed.The report is a summary of the findings presented in Goldberg (1969), a monograph which is available to readers wishing additional details of the investigation. Help with the design and implementation of the project was generously provided by William A. Bricker, Leslie A. Davison, and Vello Sermat. The author also wishes to acknowledge, with great thanks, the research contributions of Richard R. Jones, Gale H. Roid, Steven G. Ashton, Edwin S. Shiman, and Molly Stafford. Research funds for this project were first provided by the Oregon State System of Higher Education and by the University of Oregon through its Institute of College Teaching. Major support for the data analyses was provided by the Office of Education (Grant No. OEG-4-7-061693-0420), and later by Grant No. MH12972 and Grant No. MH10822 from the National Institute of Mental Health, U.S. Public Health Service. Preliminary data analyses were carried out using the facilities of the Computing Center at the University of Oregon; the analyses were completed at the Computing Center of Oregon Research Institute, and the Health Sciences Computing Facility, UCLA, sponsored by N.I.H. Grant FR-3. 相似文献
12.
Dr. Paul Kelter Ken Hughes Anne Murphy Philip Roskos 《Journal of Science Teacher Education》1995,6(1):57-59
This material is based upon work supported in part by grants from the National Science Foundation (Grant No. TPE-8955230),
the American Chemical Society (Contract No. ESI-9353374), and the Eisenhower Title II funds (Grant No. 524-2 and others).
Any opinions, findings, conclusions, and/or recommendations expressed in this article are those of the authors and do not
necessarily reflect those of the granting organizations. 相似文献
13.
LetB(X)andS(X)standfortheunitballandunitsphereofanormedspaceX ,respectively .x∈S(X)iscalledanextremepointofB(X) providedthatfory ,z∈B(X) ,x =y z2 implies y =z .DenotethesetofallextremepointsofB(X)byExtB(X) .XiscalledrotundprovidedthatS(X) =ExtB(X) .Therotundspacesarerelatedtotheoperationresearch ,thecontroltheory ,etc[1] . LetΦbeaevenconvexfunctionwithΦ(0 ) =0 ;Φ(u) >0 (u≠ 0 ) ;limu→ ∞ Φ (u) = ∞ .LetXbeanormedspace ,G Rnbeaboundedmeasurableset ,and (G ,∑ ,μ)beameasur… 相似文献
14.
The choice of self-concordant functions is the key to efficient algorithms for linear and quadratic convex optimizations,
which provide a method with polynomial-time iterations to solve linear and quadratic convex optimization problems. The parameters
of a self-concordant barrier function can be used to compute the complexity bound of the proposed algorithm. In this paper,
it is proved that the finite barrier function is a local self-concordant barrier function. By deriving the local values of
parameters of this barrier function, the desired complexity bound of an interior-point algorithm based on this local self-concordant
function for linear optimization problem is obtained. The bound matches the best known bound for small-update methods.
Project supported by the National Natural Science Foundation of China (Grant No.10771133), the Shanghai Leading Academic Discipline
Project (Grant No.S30101), and the Research Foundation for the Doctoral Program of Higher Education (Grant No.200802800010) 相似文献
15.
Single phase Fe5C2 intermetallic compound was prepared by mechanical alloying method. The phase and crystal structure of sample were analyzed with X-ray differaction spectrum. The decomposing temperature of the Fe5C2 compound is 596.4℃ determined by the DSC curve. It is further shown that the size of nanometer crystal grain is an important condition for carrying out the solid state reaction at room temperature and normal pressure. 相似文献
16.
1 Introduction Microactuators are the key devices of micro-electro-mechanical system( MEMS) . For many MEMS devicessuch as switches , optical attenuators , pumps andvalves to function, microactuators are required . Mo-tion of microactuators can be achieved by several kindsof actuation mechanisms . Electrostatic ,piezoelectric ,magnetostrictive, magnetic ,thermomechanical actua-tors have been reported[1-5].Among the different actu-ation principles ,the electrostatic actuationis predomi-nant… 相似文献
17.
关于混沌洛伦兹系统和陈系统中的广义投影同步 总被引：1，自引：1，他引：1
1 Introduction Since Pecora and Carroll[1]showed that it is possibleto synchronize two identical chaotic systems , chaossynchronization has been intensively and extensivelystudied due to its potential applications in secure com-munication,ecological systems ,systemidentification,etc.(see [2] and a huge volume of references citedtherein) . Among all kinds of chaos synchronizations ,projec-tive synchronization is one of the most noticeableones .This kind of synchronization was first observedin … 相似文献
18.
In this paper, dynamics in the oscillations of the relative atomic population in two periodically driven and weakly coupled Bose-Einstein eondensates (BECs) was qualitatively studied. Using the well-known Melnikov method, the conditions of existence of the periodic and chaotic coherent atomic tunnellings were given in the model. Our results indicate the typical route from bifurcation of the limited circles to chaos, and are in agreement with the previous numerical results. 相似文献
19.
The Bacillus firmus was immobilized into Ca-alginate beads according to the different initial biomass concentration, calcification time and activation time.Three types of immobilized Bacillus firmus beads were packed respectively in trickling biofilter to purify xylene contained waste gases,and the performance of immobilized-cell biofilter was compared with traditional biofilm attached biofilter packed with two types of ceramic pellets.The results showed that three types of immobilized beads had different capabilities for removing xylene and life-spans.Higher initial biomass in immobilized beads resulted in better performance but shorter life-span.Activation process can remarkably enhance the activity of bacteria,and the removal efficiency of xylene can substantially be improved.Calcification time had influence on life-span of immobilized beads.Without acclimation,the cell-entrapped biofilter can obtain the maximum elimination capacity of 92.4 g/(m~3·h).However,compared with biofilm attached biofilter,it has a poorer intrinsic drawback in volatile organic compounds (VOCs) removal due to the existence of excess mass transfer resistance. 相似文献
20.
We present a new algorithm for manifold learning and nonlinear dimensionality reduction. Based on a set of unorganized data
points sampled with noise from a parameterized manifold, the local geometry of the manifold is learned by constructing an
approximation for the tangent space at each point, and those tangent spaces are then aligned to give the global coordinates
of the data points with respect to the underlying manifold. We also present an error analysis of our algorithm showing that
reconstruction errors can be quite small in some cases. We illustrate our algorithm using curves and surfaces both in 2D/3D
Euclidean spaces and higher dimensional Euclidean spaces. We also address several theoretical and algorithmic issues for further
research and improvements.
Project supported in part by the Special Funds for Major State Basic Research Projects (Grant No. G19990328) and Foundation
for University Key Teacher by the Ministry of Education(Grant No.CCR-9901986) 相似文献