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281.
分流模型PID与鲁棒补偿的复合控制策略   总被引:1,自引:0,他引:1  
提出了一种基于分流模型PID与鲁棒补偿的复合控制策略,这种控制器具有非线性滤波、增益自调整、鲁棒性好等优良特性。由于分流模型的输出是稳定、光滑且有界,可以构造一类具有输出光滑、有界并且增益自调整的PID控制器,其可设计一类安全控制系统.将分流模型PID与鲁棒补偿控制相结合,有效地解决了参数不确定情况下的一类非线性系统的鲁棒控制问题。通过倒立摆控制系统的仿真研究,验证了控制策略的有效性。  相似文献   
282.
The problem of comprehensive evaluation of living basis for small businesses is discussed, based on fuzziness of index, a corresponding fuzzy state comprehensive evaluation method is presented; the good results that is, the evaluation of living basis for small business are illustrated by a simulated example.  相似文献   
283.
In recent years, SmCo series thin films have been found to be good candidates for fabricating integrated electromagnetic components and ultrahigh density magnetic recording media[1,2]. Up to now,intensive studies of such films have been carried out in order to obtain appropriate microstructure, crystallographic orientation and other properties. Substitution of Cu or Ni for Co in SmCo/Cr series films leads to a decrease of the saturation magnetization, magnetic switching volume, and to an increase of uniaxial anisotropy and coercivity[3-5].Various deposition conditions have also been investigated[6]. The large increase in coercivity for the annealed SmCo/Cr films is due to the growth of crystallitest[7,8]. In this article, we report a study of the deposition process,structure, and magnetic behavior of sputtered Sm (Co,Cu, Ti)/Cr series thin films.……  相似文献   
284.
285.
Summary Estradiol-17 β is a stronger estrogen than estriol for the genomic response of estrogens. Estriol is a stronger estrogen than estradiol-17 β for the estrogeninduced uterine eosinophilia and the 6h increase in the uterine wet weight13.  相似文献   
286.
t(1;22) is the principal translocation of acute megakaryoblastic leukemias. Here we show this chromosomal rearrangement to result in the fusion of two novel genes, RNA-binding motif protein-15 (RBM15), an RNA recognition motif-encoding gene with homology to Drosophila spen, and Megakaryoblastic Leukemia-1 (MKL1), a gene encoding an SAP (SAF-A/B, Acinus and PIAS) DNA-binding domain.  相似文献   
287.
以魏岗乡为例,研究淮河上游沿河平原农村居民点的空间分布模式以及农村居民点空间分布的相关因素.结果表明,该区农村居民点总体呈现一种随机分布的模式,局部呈现聚集、团状、带状分布格局;居民点在各个坡向均有分布,以东南方向最多,正东方向、西北方向、东北方向稍多.农村居民点受道路、海拔、坡度影响比较明显,受坡向影响相对较小.在局部区域内受道路交通、地形制约比较明显;随着海拔及距离的增加,居民点面积呈现先增加后减少的趋势,不同区域范围内居民点面积差别很大;随着坡度的增加,居民点面积呈现出不断减少的趋势.  相似文献   
288.
A ductile and super strong nanostructured twinning-induced plasticity(TWIP) steels were fabricated by cold rolling and recovery treatment.This strong and ductile nanostructured alloy can be used for the anti-intrusion part of body-in-white. Cold rolling was used to produce intensive nano-twins so that the microstructure was greatly refined. Recovery is employed to anneal dislocations for improving the ductility. A physical model is proposed to describe the relationship between the yield stress and the twin density. Furthermore,the present work also found that the activation energy for recovery is 160 J/mol,which implies that the recovery mechanism is governed by dislocation core diffusion.  相似文献   
289.
Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ 287. This quasar shows quasi-periodic optical outbursts at 12-year intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened 20 days later.  相似文献   
290.
Chen TY  Tesanovic Z  Liu RH  Chen XH  Chien CL 《Nature》2008,453(7199):1224-1227
Since the discovery of superconductivity in the high-transition-temperature (high-T(c)) copper oxides two decades ago, it has been firmly established that the CuO(2) plane is essential for superconductivity and gives rise to a host of other very unusual properties. A new family of superconductors with the general composition of LaFeAsO(1-x)F(x) has recently been discovered and the conspicuous lack of the CuO(2) planes raises the tantalizing question of a different pairing mechanism in these oxypnictides. The superconducting gap (its magnitude, structure, and temperature dependence) is intimately related to pairing. Here we report the observation of a single gap in the superconductor SmFeAsO(0.85)F(0.15) with T(c) = 42 K as measured by Andreev spectroscopy. The gap value of 2Delta = 13.34 +/- 0.3 meV gives 2Delta/k(B)T(c) = 3.68 (where k(B) is the Boltzmann constant), close to the Bardeen-Cooper-Schrieffer (BCS) prediction of 3.53. The gap decreases with temperature and vanishes at T(c) in a manner consistent with the BCS prediction, but dramatically different from that of the pseudogap behaviour in the copper oxide superconductors. Our results clearly indicate a nodeless gap order parameter, which is nearly isotropic in size across different sections of the Fermi surface, and are not compatible with models involving antiferromagnetic fluctuations, strong correlations, the t-J model, and the like, originally designed for the high-T(c) copper oxides.  相似文献   
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