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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A pseudohyperbolic problem of optimal control of intratumoral drug distribution is formulated. It takes into account the heterogeneity
of tumor tissues and effects of convection diffusion in a fissured porous medium. A mathematical model constructed and the
corresponding optimal control problem are shown to be correct.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 147–154, November–December 2007. 相似文献
992.
Yu. N. Pavlovskii 《Automation and Remote Control》2007,68(9):1492-1501
The main notions and facts of the geometrical decomposition theory were characterized in brief. The E.S. Pyatnitskii principle of decomposition was treated as the solution of the problem of assignment of feedback controls so that the controlled system admits a decomposition suitable for realization of the control objectives. It was hypothesized that this method of control is advisable if the complexity of the controlled system exceeds a certain limit. 相似文献
993.
Parallelization of the global extremum searching process 总被引:1,自引:0,他引:1
Yu. G. Evtushenko V. U. Malkova A. A. Stanevichyus 《Automation and Remote Control》2007,68(5):787-798
The parallel algorithm for searching the global extremum of the function of several variables is designed. The algorithm is based on the method of nonuniform coverings proposed by Yu.G. Evtushenko for functions that comply with the Lipschitz condition. The algorithm is realized in the language C and message passing interface (MPI) system. To speed up computations, auxiliary procedures for founding the local extremum are used. The operation of the algorithm is illustrated by the example of atomic cluster structure calculations. 相似文献
994.
A. V. Koltygin Yu. P. Tsynovnikova O. A. Kol’ 《Russian Journal of Non-Ferrous Metals》2007,48(5):347-348
In the last years, there is carried out an intensive search for new molding mixtures capable of replacing sand-argillaceous mixtures whose properties have already been well studied. Unfortunately, the majority of them form a mold in the course of the hardening of a bonding agent, which requires creating a complex system for the regeneration of the used sand. In this connection, we investigated a waterless molding mixture with the use of organobentonite as the binder, which does not require any changes in the technological process of green-sand molding. The influence of the amount and composition of the solvent on the properties of waterless mixtures is estimated. 相似文献
995.
C.Y. Tang C.P. Tsui B. Stojanovic M. Kojic 《International Journal of Mechanical Sciences》2007,49(10):1179-1191
In this study, Hill's muscle theory coupled with fatigue was proposed to describe mechanical behaviours of skeletal muscles. The force developed by a fatigued muscle was described by a muscle fatigue formula which was a time function of the activation αa and the stretch λ. The modified Hill's muscle theory was hence incorporated into a three-dimensional (3D) finite element model using the PAK finite element code. In this paper, the theoretical derivation of the 3D muscle model was firstly described. After presenting the method of establishing the finite element programme, a case example of studying the mechanical response of a frog gastrocnemius muscle was used to illustrate the applicability of the proposed methodology. The effects of the muscle fatigue on the deformation as well as the stress and strain distribution of the frog muscle subject to a cyclic activation function have been determined. An experiment capturing the real-time shape change of a frog muscle was also conducted to assess the applicability of the proposed method. A comparison between the deformed shapes of the predictive model and the frog muscles was also made. It was shown that the method is capable of providing a reasonable model for describing the mechanical behaviour of skeletal muscles. 相似文献
996.
997.
998.
T. Luo C. Yu L.-S. Yan S. Kumar Z. Pan A.E. Willner 《Photonics Technology Letters, IEEE》2006,18(15):1606-1608
We demonstrate a simple optical-fiber-based autocorrelator for picosecond short pulses based on degree-of-polarization measurement while tuning the relative delay of the two orthogonal polarization states of the pulse. The pulsewidths of 20-, 40-, and 80-GHz pulse trains and 2-ps pulses generated by a mode-locked laser are measured. The <-10-dBm optical powers are used in the experiment. The measurement results agree well with the measurements using conventional techniques. Compared with conventional autocorrelators, this technique has the advantages of 1) wavelength independent, 2) significant less alignment, and 3) no high power required. 相似文献
999.
The energy and wave functions of localized electron states in a quantum well in a high magnetic field arbitrarily oriented with respect to the layers of the structure, and a high transverse electric field are studied. The situation where the quantum-confined energy and the Landau energy are close to each other is considered. The evolution of the spectrum with varying orientation of the magnetic field over the entire angle range is studied. 相似文献
1000.