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981.
《AEUE-International Journal of Electronics and Communications》2014,68(6):550-560
In this paper, an in-depth comparative analysis of the most accepted and approved Rayleigh fading channel simulators is presented. Our study addresses the three common methods for generating time-correlated Rayleigh fading processes: the inverse discrete Fourier transform (IDFT) method, the filtering white Gaussian noise (FWGN) method and the sum-of-sinusoids (SOS) method. Totally seven models, including the recently proposed models, are analyzed and compared with Clarke's reference model. We use four quantitative measures for judicious assessment of the quality of generated processes in terms of both first-order and second-order statistics. Additionally, these measures cover analysis in time domain as well as in frequency domain. An evaluation of the computational effort is also depicted. The simulation results suggest that the recently published Wang's model is very attractive and it outperforms all SOS-based models. We conclude that Zheng and Xiao's first model remains the best choice among Zheng and Xiao's family models. Several other important remarks and conclusions about the accuracy and the capability of the different Rayleigh fading simulators are driven from this study. 相似文献
982.
A single-molecule diode with significant rectification and negative differential resistance behavior
《Organic Electronics》2014,15(2):484-490
A series of ferrocenylalkanethiol (HSCnFc) single molecular junctions are modeled and their rectification ratios (RRs) are up to 100 (for HSC11Fc), which agrees with the experiments of Whitesides et al. Not only explanation to the origin of the remarkable large RR is given, but also the reason why one order deviation of RR between HSC11Fc and HSC9Fc is discussed and depicted, which was not pointed out by previous researchers. The single asymmetric accessible molecular orbital (MO) model is evaluated, which is different from the Donor (D)–Acceptor (A) models reported before and a clear negative differential resistance (NDR) behavior is found and explained in the HSC11Fc based device. 相似文献
983.
本文简介了多种现场网络与光纤网络互联的关键设备:PVC多媒体联网平台(多媒体用户接口)、光线路终端及光网络用户单元,评述了它们在小区的应用。 相似文献
984.
R. S. Meghwal T. C. Loya S. L. Kakani 《Journal of Superconductivity and Novel Magnetism》2009,22(7):659-665
We consider the extended two-band s–f model with additional terms, describing intersite Cooper pairs’ interaction between
4f (5f) and conduction electrons. Following Green’s function technique and equation of motion method, self-consistent equations
for superconducting order parameter (Δ) and magnetic order parameter (m
f
) are derived. The expressions for specific heat, density of states, and free energy are also derived. The theory has been
applied to explain the coexistence of superconductivity and ferromagnetism in hybrid rutheno-cuprate superconductors RuSr2RECu2O8 (RE = Gd, Eu). The theory shows that it is possible to become superconducting if the system is already ferromagnetic. A study
of specific heat, density of states and free energy is also presented. The agreement between theory and experimental observations
is quite satisfactory.
相似文献
985.
Francisco López-Carrasquero Giuseppe Giammanco Angélica Díaz Johanna Dávila Carlos Torres Estrella Laredo 《Polymer Bulletin》2009,63(1):69-78
A series of comb like poly(p-n-alkylstyrene)s with linear alkyl groups, containing even numbers of carbon atoms from 12 up to 22 were synthesized by radical
polymerization and characterized by FTIR, 1H NMR, TGA, TVA DSC, and WAXS. All polymers were obtained in good yields and were soluble in organic solvents as chloroform,
dichloromethane or tetrahydrofuran and insoluble in methanol; they are stable up to temperatures near 300 °C. On the other
hand, the alkylic side chains of all series are able to crystallize in a paraffinic phase in which the melting temperature
and enthalpy increase with the methylene number of the n-alkyl chain. 相似文献
986.
高微征 《太原重型机械学院学报》2009,(2):171-173
首先肯定了皮日休对儒家“经世致用”思想的继承,然后分析了皮日休对古文运动的代表韩愈等人“文以明道”观点的发扬,最后着重论述了皮日休通过对统治者的讽刺、鞭挞和对人个体生命的尊重,实现了对儒家中庸思想的突破。 相似文献
987.
This paper describes the classification of various human actions from brain activity. In particular, we focus on grasping movements and estimate grasping patterns from electroencephalogram (EEG) data. EEG data is converted to grasping features by using a common spatial pattern filter (CSP filter), and the features are subsequently classified into grasping categories by using the k-nearest neighbor method. We tested the pipeline of feature extraction and classification on the EEG dataset. The EEG data were acquired while participants grasped an object according to the Cutkosky’s grasping taxonomy, in which grasping movements are categorized into nine power-type grasping patterns and seven precision-type grasping patterns. The best classification rate for 9-class power-type grasping patterns was 48% and for 7-class precision-type grasping patterns was 40%. 相似文献
988.
《Costume》2013,47(1):55-74
AbstractThis article explores women’s social status in modern China during the turbulent history of the early twentieth century through an examination of examples of qipao and related images that date approximately from the 1920s to the 1940s. The discussion aims to demonstrate the evolving styles that reveal women’s growing emancipation, and which foreground their bodies as the point of social contention. Qipao is often presented as a national costume in the Chinese culture, but its identity is fraught with gender related issues as well as its role as a tool of social redefinition. 相似文献
989.
990.
In the first article [Lebrun R, Dutfoy A. An innovating viewpoint of the isoprobabilistic Nataf transformation with the copula theory within exceedance threshold uncertainty analysis. Probabilistic Structure Engineering Structural Reliability. 2008 [in press]], we showed that the Nataf transformation is a way to model the dependence structure of a random vector by a normal copula, parameterized by its correlation matrix. Following this analysis, we propose an extension of this transformation to any elliptical copula, and give the equivalent of the First Order Reliability Method (FORM) and the Second Order Reliability Method (SORM) for this generalization. In particular, we derive the Breitung asymptotic approximation in this new context. 相似文献