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81.
We obtain a necessary and sufficient condition for a discrete-time nonlinear system to be locally state equivalent to the nonlinear observer form. The result looks similar to the continuous counterpart except for the fact that Ad-operation is utilized instead of ad-operation. 相似文献
82.
83.
CAO Wei-feng WANG Wen-boBeijing University of Posts Telecommunications Beijing P.R. China 《中国邮电高校学报(英文版)》2005,12(4)
1IntroductionCurrently,smart antenna technology can greatly en-hance system performance and i mprove the system ca-pacity so that it has been considered as a keytechnologyinthe third generation wireless communicationsystems .The researches on channel model , beamforming algo-rithms and receive algorithms have been widely carriedout and a great many of proposition have beensubmittedtothe 3th Generation Project Partner (3GPP) . Fromthe viewpoint of link-level and system-level research,many asp… 相似文献
84.
基于MATLAB在化工优化设计中的应用 总被引:2,自引:0,他引:2
结合化工优化计算的实例,着重介绍如何应用MATLAB7.0提供的优化工具箱来对线性规划及非线性规划模型进行求解。 相似文献
85.
Total simulation model of the thermo-mechanical process in shape rolling of steel rods 总被引:2,自引:0,他引:2
The production of steel reinforcing bars for civil engineering is investigated by means of FEM-simulation. An integrated system for computing appropriate thermo-mechanical parameters of the rolling process is proposed. Generalized plane strain approach and coupled thermal-mechanical solution are applied. The microstructural model combines both the effect of the recrystallization mechanisms (static, dynamic and metadynamic) upon the austenite grain forming in hot rolling and that of phase transformation upon the final microstructure. The phases are created during interrupted below the temperature of martensite transition cooling. Thus a typical industrial process for thermo-mechanical strengthening of reinforcing bars, known as Tempcor-process is considered. Computational results are validated to experimental measured mechanical properties of the steel. By means of computer simulation the system can perform different solutions, giving the possibility to obtain a reasonable choice of different thermo-mechanical rolling conditions. 相似文献
86.
Vibration cavitation erosion tests were carried out on Ni-Mn-Ga alloys of three different crystal structures: (1) the cubic austenite, (2) the non-modulated tetragonal martensite (T) and (3) the five-layered martensite (5M). All Ni-Mn-Ga alloys exhibited cavitation behaviour characterized by a step-wise curve of mass loss versus test time. This behaviour is correlated to the microstructural nature of the alloys as well as the surface conditions of the pre-test samples. The type and concentration of the defects at the surfaces were critical to the cavitation resistance of the alloys. The best cavitation resistant alloy was of a cubic austenitic structure, followed with the alloy of a tetragonal T-martensite. The largest material loss was found in the alloy with a 5M martensite. All the studied Ni-Mn-Ga alloys had an excellent cavitation resistance compared to that of the reference stainless steel, and they even excelled some NiTi alloys found in literature. This may be due to the superelasticity of the cubic austenite and the twinning of the martensitic phases. 相似文献
87.
Fe100-xPtx(x=30at.%-60at.% ) nanocomposite films were deposited on natural-oxidized Si(100) substrates by magnetron sputtering. The as-deposited films were annealed between 373 and 1073 K. In situ X-ray diffraction shows that the FePt nanocomposite films undergo a phase transformation from a disordered FCC phase to an ordered L10 phase between 673 and 773 K. The coercivity is 306 kA·m-1 whiles the average grain sizes is about 10 nm in the optimized FePt alloy film sample annealed at 673K. The adjustable coercivity and fine grain size suggest that this FePt nanocomposites system is suitable as recording media at extremely high areal density. 相似文献
88.
In this work, we study dynamic provisioning of multicast sessions in a wavelength-routed sparse splitting capable WDM network
with an arbitrary mesh topology where the network consists of nodes with full, partial, or no wavelength conversion capabilities
and a node can be a tap-and-continue (TaC) node or a splitting and delivery (SaD) node. The objectives are to minimize the
network resources in terms of wavelength-links used by each session and to reduce the multicast session blocking probability.
The problem is to route the multicast session from each source to the members of every multicast session, and to assign an
appropriate wavelength to each link used by the session. We propose an efficient online algorithm for dynamic multicast session
provisioning. To evaluate the proposed algorithm, we apply the integer linear programming (ILP) optimization tool on a per
multicast session basis to solve off-line the optimal routing and wavelength assignment given a multicast session and the
current network topology as well as its residual network resource information. We formulate the per session multicast routing
and wavelength assignment problem as an ILP. With this ILP formulation, the multicast session blocking probability or success
probability can then be estimated based on solving a series of ILPs off-line. We have evaluated the effectiveness of the proposed
online algorithm via simulation in terms of session blocking probability and network resources used by a session. Simulation
results indicate that our proposed computationally efficient online algorithm performs well even when a fraction of the nodes
are SaD nodes. 相似文献
89.
�����������������������������ܿ��������о� 总被引:5,自引:1,他引:4
白马庙气田蓬莱镇气藏储层致密 ,孔隙结构复杂 ,非均质性强 ,单井产能低 ,研究储层特征和受控因素 ,加强储层改造方是气藏效益开发的出路。储层精细研究揭示 ,气井产能受沉积相和构造条件控制 ;高、中产井与大而厚、物性好的河口坝、河道砂坝沉积微相有关 ,纵向上具很强的层段性 ,主产层集中在Ⅳ~③、Ⅲ~③两套砂组 ,其钻探成功率分别达 82 %和 10 0 % ;平面上多分布于主体构造和东南鼻状突起 ,二者高、中产能井分别占 30 %和 70 %。在深入的地质研究和储层压裂评层选井的基础上 ,采用多层打开、分层压裂、多层合采的方法可提高气井产能 ,并形成了一套行之有效的压裂评层选井的综合配套技术。采用该技术优选出 19口井 ,已实施 5口井全获成功 ,气产量成倍或十几倍增加 ,其中白浅 4 5井气无阻流量高达 18× 10 4m3 /d ,白浅 38井投产 16 5d净增产值 10 0余万元 相似文献
90.