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51.
设$(A,B,V,W,\psi,\phi)$是一个Morita Context,具有一对零态射$\psi=0$, $\phi=0$, $C =\left ( \begin{array} {cc}A & V \\W & B \end{array}\right)$是对应的Morita Context环.本文给出了$C$与$A,B,V,W$之间关于环的$\pi$-正则性、semiclean性、Mophic性和环的Exchgange性、Potent性、GM性的关系. 相似文献
52.
Pinning effect of lead lanthanum titanate (PLT) ferroelectric thin films with excess PbO of 20 mol% has been studied for deposition on diffe rent substrates. Silicon, sapphire and quartz were used as substrates on which P t/Ti or LaNiO3 thin films were deposited as bottom electrodes. Electron probe analysis results showed that there was still a certain amount of excess Pb in PLT films after annealing at 550 ℃ for 1 h, and the amount of it was dependent on the substrate used. The distribution of excess Pb in the films was investig ated by Auger electron spectroscopy depth profile. It was shown that the substrates and the bottom electrodes had significant effects on the content and distrib ution of excess Pb in PLT films. The excess Pb and its accumulation at the inter face between the film and bottom electrode may act as pinning centers and have a pinning effect on domains, which can be observed by abnormal P-E hysteresis loops and abnormal C-V curves. The excess Pb content in the films and the accumulation of Pb at the interface were high in PLT films deposited on Pt/Ti/S i, and considerable pinning effect was observed. As LaNiO3 would absorb most part of the excess Pb in PLT films, the content of excess Pb in the films deposited on LaNiO3/Si was very low and the pinning effect was hardly observed. 相似文献
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A Fully Vectorial Effective Index Method for Accurate Dispersion Calculation of Photonic Crystal Fibres 下载免费PDF全文
A fully vectorial effective index method is developed for accurate dispersion calculation of photonic crystal fibres (PCFs). In order to improve the accuracy of the model, different values for the effective core radius are used when PCFs have different fibre parameters. The accuracy of our approach is demonstrated by comparing our results with other numerical and experimental results reported in literature. It is found that the accuracy of the fully vectorial effective index method is improved and our results agree well with accurate numerical results obtained by other methods as well as the previously reported experimental data. 相似文献
55.
Design of Two-Dimensional Photonic Crystal Edge Emitting Laser for Photonic Integrated Circuits 下载免费PDF全文
An edge emitting laser based on two-dimensional photonic crystal slabs is proposed. The device consists of a square lattice microcavity, which is composed of two structures with the same period but different radius of air-holes, and a waveguide. In the cavity, laser resonance in the inner structure benefits from not only the anomalous dispersion characteristic of the first band-edge at the M point in the first Brillouin-zone but also zero photon states in the outer structure. A line defect waveguide is introduced in the outer structure for extracting photons from the inner cavity. Three-dimensional finite-difference time-domain simulations apparently show the in-plane laser output from the waveguide. The microcavity has an effective mode volume of about 3.2(λ/nslab)^3 for oscillation mode and the quality factor of the device including line defect waveguide is estimated to be as high as 1300. 相似文献
56.
基于奇异值分解的特征跟踪方法 总被引:1,自引:0,他引:1
在传统的基于模板匹配的跟踪方法中,均是给定一个模板,然后从图像中各个位置取出一个个与模板大小一致的区域进行相似性度量,找出与模板距离最小的一个区域作为当前模板,以便进行下一步的匹配跟踪工作。在景象匹配和相关跟踪过程中,由于所面临的大多数是变化的场景,实时获取的图像与预存模板之间存在比较大的差异,传统相关匹配方法的应用就会受到限制;而且在跟踪过程中,随时更新模板会造成跟踪性能对扰动过分敏感,从而产生漂移。首先拍摄目标不同角度的图像(尽可能包含目标可能出现的所有情况),构成目标图像训练集合,抽取出特征矩阵,对它进行奇异值分解,构成一个关于目标的多维空间。然后再用匹配方法在全局范围搜索,找出目标的大致位置,并利用收敛方法在确定的大致位置内进行搜索,确定目标的仿射变换系数,从而得到一个目标位置的确切描述。 相似文献
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采用半微量相平衡方法测定了三元体系La(NCS)3.4.5H2O-B15C5-C2H5OH在298.15K的溶解度,测定了各饱和溶液的折光率。 相似文献
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