排序方式: 共有26条查询结果,搜索用时 15 毫秒
1.
《光学原理》(Principles of Optics)一书是玻恩与沃尔夫合著的、倍受好评的光学经典名著。回顾、梳理与品味这一名著的撰写过程,会得到诸多感悟。教书育人、著书立说的物理教育家以及物理学家,都可以从中得到一把尺子,用以衡量自己的工作。这有利于中国物理学的发展。 相似文献
2.
Typical random codes (TRCs) in a communication scenario of source coding with side information in the decoder is the main subject of this work. We study the semi-deterministic code ensemble, which is a certain variant of the ordinary random binning code ensemble. In this code ensemble, the relatively small type classes of the source are deterministically partitioned into the available bins in a one-to-one manner. As a consequence, the error probability decreases dramatically. The random binning error exponent and the error exponent of the TRCs are derived and proved to be equal to one another in a few important special cases. We show that the performance under optimal decoding can be attained also by certain universal decoders, e.g., the stochastic likelihood decoder with an empirical entropy metric. Moreover, we discuss the trade-offs between the error exponent and the excess-rate exponent for the typical random semi-deterministic code and characterize its optimal rate function. We show that for any pair of correlated information sources, both error and excess-rate probabilities exponential vanish when the blocklength tends to infinity. 相似文献
3.
Arzhang AngoshtariArash Yavari 《Physics letters. A》2011,375(10):1281-1285
A rigorous proof for convergence of the Wolf method (Wolf et al., 1999 [9]) for calculating electrostatic energy of a periodic lattice is presented. In particular, we show that for an arbitrary lattice of unit cells, the lattice sum obtained via Wolf method converges to the one obtained via Ewald method. 相似文献
4.
Intrinsic viscosities for a given polyelectrolyte in salt free and low-salt solvents reported in literatures are normally not comparable, because of inadequate valuation procedures. This article describes a theoretically justified reliable method, which is free of any model assumptions: The so called Wolf plot (logarithm of the relative viscosity as a function of polymer concentration) enables the unequivocal determination of intrinsic viscosities for all kinds of macromolecules, irrespective of whether they are chain molecules of different architecture or globular polymers, whether they are charged or uncharged. The validation of the method was examined by evaluation of the viscosities of a polyelectrolyte, some uncharged polymers of different architectures, uncharged polymer blends, and some literature data. 相似文献
5.
6.
在防空作战中,目标威胁估计是指挥控制过程的重要一环,是决策和指挥的重要依据。BP神经网络能够解决目标威胁估计问题,但存在收敛速度慢、易陷入局部最优等缺点。提出将遗传算法(Genetic Algorithm,GA)的选择、交叉和变异操作融入到狼群算法(Wolf Pack Algorithm,WPA)中,提出了GA-WPA算法,以提高狼群算法的收敛速度。在此基础上,利用所提出的GA-WPA算法对BP神经网络进行优化,确定最优初始权值和阈值。最后,将优化后的BP神经网络解决地面防空系统目标威胁估计问题。仿真实验表明,所提算法能够有效克服BP神经网络收敛速度慢、易陷入局部最优等缺点,能够提高目标威胁估计的准确性和适应性。 相似文献
7.
本文介绍了2007年度国家最高科学技术奖获得者闵恩泽院士的主要科学技术成就与贡献,包括:(1)不断研发炼油新催化剂,奠定中国石油炼制催化剂制造技术基础--炼油催化应用科学的奠基人;(2)自主创新,开发新催化材料和新反应工程--石油化工技术自主创新的先行者;(3)开发绿色石化技术,从源头根治环境污染--绿色化学的开拓者三部分内容. 相似文献
8.
Shiping Li Zhixin Wang Rui Gu Yiwu Zhao Wenzhe Huang Zhenzhong Wang 《Natural product research》2016,30(15):1712-1717
A new epidioxy-tetracyclic triterpenoid, 3-(2-hydroxyacetoxy)-5α, 8α-peroxydehydrotumulosic acid (10), along with nine known compounds were isolated from Poria cocos Wolf (Polyporaceae). Their structures were determined by extensive spectroscopic analyses and comparison with literature data. The cytotoxicity of these compounds against human cancer cell lines MNK-45 was evaluated by MTT method. 相似文献
9.
10.