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31.
Qiangfu Zhao Zhong Wang Youan KeDept. of Electronic Eng. Beijing Institute of Technology P.O.Box Beijing China 《系统工程与电子技术(英文版)》1991,(2)
It has long been realized that the problem of radar imaging is a special case of image reconstruction in which the data are incomplete and noisy. In other fields, iterative reconstruction algorithms have been used successfully to improve the image quality. This paper studies the application of iterative algorithms in radar imaging. A discrete model is first derived, and the iterative algorithms are then adapted to radar imaging. Although such algorithms are usually time consuming, this paper shows that, if the algorithms are appropriately simplified, it is possible to realize them even in real time. The efficiency of iterative algorithms is shown through computer simulations. 相似文献
32.
XI Zengzhe LI Zhenrong XU Zhuo ZHANG Liangying & YAO Xi . Functional Materials Research Laboratory Tongji University Shanghai China . Key Laboratory of the Ministry of Education Xi抋n Jiaotong University Xi抋n China 《科学通报(英文版)》2003,48(19):2038-2040
It has been reported that the single crystal of relaxor ferroelectrics (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) with the compositions near the morphotropic phase boundary (MPB, 0.28相似文献
33.
Zhu Canyan Wang Yiming Yang Huibao & Liu Jiasheng School of Electronics Information Engineering Soochow Univ. Suzhou P.R.China 《系统工程与电子技术(英文版)》2006,17(4):875-882
1. INTRODUCTION As the development of technologies of digital signal processing and integrated circuits, the structure of wireless communication system has been improved. Many schemes for software defined radio (SDR) systems have been developed since 1995, and they can be divided into five tiers of solutions according to their developing history and their definitions[1]. The five tiers are conventional hardware-implemented scheme; software-controlled radio scheme; SDR, that implements m… 相似文献
34.
1 Results Amphiphilic block copolymers are capable of forming supramolecular assemblies resembling those observed in nature,such as spherical micelles,worm micelles,and vesicles.Changing the solvent composition,ionic strength or pH of the polymer solution may induce the self-assembly of block copolymers or trigger the transition between the geometries of noncovalent assemblies.In the current work,we have synthesised starlike amphiphilic block copolymers having hydrophobic poly(methyl methacrylate),PMMA,core,and hydrophilic poly(acrylic acid),PAA,shell.The self-assembling characteristics of these polymers have been investigated in aqueous solutions by light scattering and direct visualisation by cryo-transmission electron microscopy (cryoTEM)[1]. Computer simulations along with the theoretical predictions made for the star-like system based on mean-field theory have been used to support the experimental observations[2]. The association of the starlike macromolecules resembles that of charged biopolymers,such as actin,since a balance between attractive and repulsive forces is required for the formation of cylindrical assemblies and can be manipulated by changing the pH or the ionic strength of the solvent[3]. 相似文献
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S. K. MISHRA Shouyang WANG K. K. LAI 《系统科学与复杂性》2007,20(3):344-349
In this paper, we introduce a new class of generalized convex function, namely, a-pseudounivex function, by combining the concepts of pseudo-univex and α-invex functions. Further, we establish some relationships between vector variational-like inequality problems and vector optimization problems under the assumptions of α-pseudo-univex functions. Results obtained in this paper present a refinement and improvement of previously known results. 相似文献
40.
A New Discipline of Science-The Study of Open Complex Giant System and Its Methodology 总被引:2,自引:0,他引:2
Qian XuesenChina Association for Science Technology Beijing ChinaYu JingyuanBeijing Institute of Information Control P.O.Box Beijing ChinaDai RuweiInstitute of Automation Chinese Academy of Sciences Beijing China 《系统工程与电子技术(英文版)》1993,(2)
This paper introduces the conception of open complex giant system and the methodology for dealing with the system, with stress on its profound significance in development of science and technology. The authors conclude that the reductionism underlying the exact science is not suitable to open complex giant system, and the only feasible alternative is the meta-synthetic engineering from the qualitative to the quantitative. 相似文献