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881.
Sei-Wang Chen Chi-Farn Chen Meng-Seng Chen Shen Cheng Chiung-Yao Fang Kuo-En Chang 《Signal Processing, IEEE Transactions on》1997,45(11):2639-2654
An unsupervised classification technique conceptualized in terms of neural and fuzzy disciplines for the segmentation of remotely sensed images is presented. The process consists of three major steps: 1) pattern transformation; 2) neural classification; 3) fuzzy grouping. In the first step, the multispectral patterns of image pixels are transformed into what we call coarse patterns. In the second step, a delicate classification of pixels is attained by applying an ART neural classifier to the transformed pixel patterns. Since the resultant clusters of pixels are usually too keen to be of practical significance, in the third step, a fuzzy clustering algorithm is invoked to integrate pixel clusters. A function for measuring clustering validity is defined with which the optimal number of classes can be automatically determined by the clustering algorithm. The proposed technique is applied to both synthetic and real images. High classification rates have been achieved for synthetic images. We also feel comfortable with the results of the real images because their spectral variances are even smaller than the spectral variances of the synthetic images examined 相似文献
882.
WU Jiada WU Changzheng ZHONG Xiaoxia SONG Zhoumo LI Fuming 《Chinese Journal of Lasers》1997,6(2):161-168
l.IntroductionowingtotheirpromisingproPertiesandPOtentialapplications,transitionmetalni-trideshavedrawngreatattentionandthepreparationandinvestigationofthesecom-poundshavebeenasubjectbothofscientificandoftechnologicalinterest.Transitionmetalnitridescombineadvantagesofexce1lenthardness,highmeltingPOint,goodchemi-calstabilityandhigheIectricalconductivity[11,henceoverlaySofthesecompoundshavefoundwideappIicationsinvariousfie1ds.Molybdenumnitrides,inparticular,havealsoemergedasverypromisingcandi… 相似文献
883.
用方差定义的激光束横向尺寸,有着普适、简单和便于利用光学元件并行运算功能的特点.本文提出一种借助改变柱形容器内吸收液浓度来直接测量各种波长激光束横向尺寸的理论和方法. 相似文献
884.
CMOS scaling into the nanometer regime 总被引:11,自引:0,他引:11
Yuan Taur Buchanan D.A. Wei Chen Frank D.J. Ismail K.E. Shih-Hsien Lo Sai-Halasz G.A. Viswanathan R.G. Wann H.-J.C. Wind S.J. Hon-Sum Wong 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1997,85(4):486-504
Starting with a brief review on 0.1-μm (100 nm) CMOS status, this paper addresses the key challenges in further scaling of CMOS technology into the nanometer (sub-100 nm) regime in light of fundamental physical effects and practical considerations. Among the issues discussed are: lithography, power supply and threshold voltage, short-channel effect, gate oxide, high-field effects, dopant number fluctuations and interconnect delays. The last part of the paper discusses several alternative or unconventional device structures, including silicon-on-insulator (SOI), SiGe MOSFET's, low-temperature CMOS, and double-gate MOSFET's, which may lead to the outermost limits of silicon scaling 相似文献
885.
The mode coupling in a helical fibre with a circular cross-section undergoing perturbations is investigated in the Serret-Frenet frame. The coupled-mode equations have been derived and are compared with the conventional ones. Applying the coupled-mode equations to a helical fibre with an elliptical core deformation, we obtained, for the first time, a rigorous analysis of the transmission characteristics of the fibre. The numerical examples show that the mode ellipticity and elliptical birefringence increase as the core ellipticity increases and also vary as the pitch or the core offset change. 相似文献
886.
常压催化加氢合成邻氨基苯酚的研究 总被引:1,自引:0,他引:1
用硅溶胶改性的漆原镍催化剂,在常压液相催化条件下,氢化邻硝基苯酚制备邻氨基苯酚的反应过程,可分为诱导期、恒速吸氢阶段、吸氢衰减期3个反应阶段.恒速吸氢阶段的吸氢速率为5×102mol/(kg·min)且与体系的温度无关,诱导期随温度的增加而变短,吸氢衰减期的长短随溶剂量的变化而变化.实验结果表明,邻氨基苯酚的收率在95%左右. 相似文献
887.
AN EFFECTIVE APPROACH FOR TWO-DIMENSIONAL POLARONS IN AN ASYMMETRIC QUANTUM DOT 总被引:1,自引:0,他引:1
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Within the framework of Feynman-Haken path integral theory, we calculate the ground-state energy of two-dimensional polarons in asymmetric quantum dots for arbitrary electron-phonon coupling constants. From a general three-dimensional Hamiltonian, some interesting problems, such as polarons in quasi-one-dimensional quantum wires and quasi-zero-dimensional asymmetric or symmetric quantum dots can be easily discussed only by taking different limit in the whole coupling regime. After the numerical calculation, we find that the relative polaronic correction increases monotonically with the decrease of effective dot size, and it becomes more pronounced with increasing dimension and asymmetry. Moreover, despite the insensitivity of relative polaronic enhancement to the variation of coupling constant at weak coupling, the correction is related to the coupling constant as the latter becomes larger. 相似文献
888.
微波在免疫组织化学中的应用 总被引:1,自引:0,他引:1
本文综述微波技术在免疫组织化学中的应用两头及其进展,着重介绍了微波在组织固定、抗原恢复和免疫染色方面的应用,并对微波免疫组织化学的应用前景进行了展望 。 相似文献
889.
890.
In this paper, we investigate strict stability of differential systems by variational Lyapunov function. We obtain some sufficient conditions and comparison theorems. 相似文献