检索结果-内蒙古大学图书馆

Generalization and propagation of spiraling Bessel beams with a helical axicon

Chinese Physics B 2012年第1期21卷 234-243页

作者： Sun Qiong-Ge Zhou Ke-Ya Fang Guang-Yu Liu Zheng-Jun Liu Shu-Tian Department of physics Harbin Institute of TechnologyHarbin 150001China Department of Automation Measurement and Control Engineering Harbin Institute of TechnologyHarbin 150001China

A generalized type of spiral Bessel beam has been demonstrated by using a spatially displaced helical axicon （HA）. The topological charge of the spiraling Bessel beams is determined by the order of the input Laguerre Gaussian （LG） beam and the topological charge of the HA. The obtained spiraling Bessel beams have an LG type of modulation along their propagation direction and exhibit annihilation-reconstruction properties. Theoretical analysis is presented, including that of the stability, propagation distance, topological charge, and spiraling dynamic characteristics. The mathematical and numerical results show that the propagation distance and helical revolution of the spiraling Bessel beams can be controlled through choosing appropriate radius of the HA.

关键词： Bessel beam helical axicon beam propagation spiral beam

来源：评论

学校读者我要写书评

暂无评论

An uplink power control algorithm using traditional iterative model for cognitive radio networks

引用

Journal of Central South University 2012年第10期19卷 2816-2822页

作者：李枫谭学治王丽 School of Electronics Information Engineering Harbin Institute of Technology Department of Automation Measurement and Control Harbin Institute of Technology

Based on the analysis of the feature of cognitive radio networks, a relevant interference model was built. Cognitive users should consider especially the problem of interference with licensed users and satisfy the signal-to-interference noise ratio （SINR） requirement at the same time. According to different power thresholds, an approach was given to solve the problem of coexistence between licensed user and cognitive user in cognitive system. Then, an uplink distributed power control algorithm based on traditional iterative model was proposed. Convergence analysis of the algorithm in case of feasible systems was provided. Simulations show that this method can provide substantial power savings as compared with the power balancing algorithm while reducing the achieved SINR only slightly, since 6% S1NR loss can bring 23% power gain. Through further simulations, it can be concluded that the proposed solution has better effect as the noise power or system load increases.

关键词： cognitive radio uplink power control interference iterative algorithm

来源：评论

学校读者我要写书评

暂无评论

Realizability of n-port resistive networks with 2n terminals

Realizability of n-port resistive networks with 2n terminals

引用

Asian control Conference

作者： Michael Z. Q. Chen Chanying Li Kai Wang Zhiqiang Zuo Minghui Yin Guanrong Chen Department of Mechanical Engineering University of Hong Kong Hong Kong China School of Automation Nanjing University of Science and Technology Nanjing China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China Department of Electronic Engineering City University of Hong Kong Hong Kong China

In this paper, we consider the realizability problem of n-port resistive networks containing 2n terminals. A necessary and sufficient condition for any real symmetric matrix to be realizable as the admittance of an n-port resistive network containing 2n terminals is obtained. The condition is based on the existence of a parameter matrix. We then focus on a three-port resistive network containing six terminals. A necessary and sufficient condition is derived for any real symmetric matrix to be realizable as the admittance of a three-port resistive network containing six terminals and at most five positive elements, whose topological structure is properly restricted.

关键词： Symmetric matrices Ports (Computers) Admittance Educational institutions Resistors Joining processes Passive networks

来源：评论

学校读者我要写书评

暂无评论

A soft sensor development for the estimation of benzene content in catalytic reformate

A soft sensor development for the estimation of benzene cont...

引用

35th International Convention on Information and Communication Technology, Electronics and Microelectronics, MIPRO 2012

作者： Ujević Andrijić, Željka Karlović, Romano Žeželj, Boris Faculty of Chemical Engineering and Technology Department of Measurement and Process Control Zagreb Croatia Rijeka Refinery Process Automation Kostrena Croatia

ISBN: (纸本)9789532330724

As vehicle emission standards become more stringent, there is an increasing need for continual monitoring of benzene content in gasoline. Since the on-line analyzers are often unavailable, and laboratory analyses are infrequently obtained, soft sensors for the estimation of benzene content of light reformate are developed. Soft sensors are developed using system identification methods. Experimental data is acquired from the refinery distributed control system (DCS) and include continuously measured variables and analyzer assays available on-line. In the present work, the development of a Finite Impulse Response (FIR) model, an Output Error (OE) model and an Auto-Regressive Model with Exogenous Inputs (ARX) model are presented. To overcome the problem of selecting the best model parameters by trial and error, genetic algorithm was used. Based on developed soft sensors, it is possible to entirely replace on-line analyzers with soft sensors by embedding the model in a DCS on-site. © 2012 MIPRO.

关键词： Benzene

来源：评论

学校读者我要写书评

暂无评论

Virtual source for rotational symmetric Lorentz-Gaussian beam

引用

Chinese Optics Letters 2012年第6期10卷 72-76页

作者：孙琼阁李爱兰周可雅刘正君方光宇刘树田 Department of Physics Harbin Institute of Technology College of Electronics and Information Engineering Beijing City University Department of Automation Measurement and Control Engineering Harbin Institute of Technology

The virtual source for generation of rotational symmetric Lorentz-Gaussian （RLG） wave whose propagating dynamics present the rotational symmetry is identified. Closed-form expressions, including integral and differential representations, are derived for this kind of Lorentz-Gaussian （LG） wave, thereby yielding paraxial approximation of the RLG beam in the appropriate regime. From the spectral representation of this wave, the first three order corrections of nonparaxial approximations are determined for a corresponding paraxial RLG beam. Moreover, the relationship between the RLG beam and the Hermite-Gaussian beam is revealed.

关键词： Optics Physics

来源：评论

学校读者我要写书评

暂无评论

Rat skin wounds tensile strength measurements in the process of healing

Rat skin wounds tensile strength measurements in the process...

引用

10th IEEE Jubilee International Symposium on Applied Machine Intelligence and Informatics, SAMI 2012

作者： Živčák, J. Hudák, R. Tóth, T. Department of Biomedical Engineering and Measurement Faculty of Mechanical Engineering Technical University of Košice Slovakia Department of Automation Control and Human Machine Interactions Faculty of Mechanical Engineering Technical University of Košice Slovakia

ISBN: (纸本)9781457701979

The goal of our investigation was to evaluate mechanical properties of the skin wounds during the first seven days of primary healing. We realized two parallel symmetrical skin incision (on the left and right side of the spine) in the general anaesthesia. Rats were divided into 7 groups. We measured tensile strength of the wound in 24, 48, 72, 96, 120, 144 and 168 hours after wounding in every group. After each day of measurement we obtained complex of tensile strength diagrams of wound tensile strength-time dependence. We observed the highest absolute strength increase after 24 hours within 5 days after wounding. In the period between 2nd and 5th day of testing we observed stagnation of the strength, labelled as "plató phase". Next significant strength increase was observed only after 6 days, with following increase of the tensile strength of skin wound. © 2012 IEEE.

关键词： Tensile strength

来源：评论

学校读者我要写书评

暂无评论

Simulation model of laser transmission and detection through cumulus

引用

Journal of Computational Information Systems 2012年第13期8卷 5517-5526页

作者： Jia, Yanxi Jiang, Shouda Department of Automation Measurement and Control Engineering Harbin Institute of Technology Harbin 150001 China

We have developed a simulation model of laser transmission and Detection through cumulus. Based on successive-order-of-scattering approach, the model describes the transmission process of the laser beam under the impact of various media which are mainly cumulus in atmosphere. In this model, the factors affecting the laser transmission include aerosol, atmospheric molecules and water vapor molecules. The distribution of liquid water droplets in cumulus is described by two-dimensional model and Mie theory is used to calculate the optical parameters. In the life cycle of cumulus, the results can correctly describe the trends of laser power respect to target height and water droplets distribution of cumulus. The model can meet the requirements of real-time simulation. The model simulation process depends on the support of several parameters including equipment geometric parameters, atmospheric optical parameters and others. © 2011 by Binary Information Press.

关键词： Laser beams

来源：评论

学校读者我要写书评

暂无评论

A novel blind source extraction algorithm for ill-conditioned mixtures

引用

Journal of Computational Information Systems 2012年第8期8卷 3339-3347页

作者： Dai, Huhe Wei, Changan Jiang, Shouda Department of Automation Measurement and Control Engineering Harbin Institute of Technology Harbin 150001 China

A new contrast function is proposed to solve blind extraction problem from ill-conditioned mixtures of Gaussian and sub-Gaussian signals, or mixtures of Gaussian and super-Gaussian signals. Firstly, we point out the limitation of the existing contrast function for hybrid mixtures. Then the new contrast function based on fourth order cross cumulants and the covariance is presented. In addition, it is proved that minimizing the new contrast function would lead to separation of the extractable sources, and the classic Gaussian-Newton method is applied to accomplish the minimizing process. Simulation results, for both nonsingular mixing matrix case and singular mixing matrix case (ill-conditioned case), validate the sequential blind extraction algorithm in which the proposed contrast function is used. © 2012 Binary Information Press.

关键词： Newton-Raphson method

来源：评论

学校读者我要写书评

暂无评论

New criteria of reachable set estimation for time delay systems subject to polytopic uncertainties

New criteria of reachable set estimation for time delay syst...

引用

7th IFAC Symposium on Robust control Design, ROCOND'12

作者： Zuo, Zhiqiang Chen, Yinping Wang, Yijing Chen, Michael Z.Q. Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China Department of Mechanical Engineering University of Hong Kong Hong Kong Hong Kong

ISBN: (纸本)9783902823038

The problem of reachable set estimation for linear systems subject to both time delay and polytopic uncertainties is considered in this paper. Our aim is to find a set as small as possible to bound the states starting from the origin by inputs with peak values. The Lyapunov-Krasovskii functional together with free-weighting matrix technique are proposed to derive some sufficient conditions for the existence of an ellipsoidal bound to estimate the states. This method eliminates the conservatism generated by Jensen's inequality and obtains a much tighter reachable set bound. In addition, the number of variables to be determined is smaller than the previous result based on the maximal Lyapunov functional. Finally, an example illustrates the merits of our proposed results. © 2012 IFAC.

关键词： Linear systems

来源：评论

学校读者我要写书评

暂无评论

Statistical theory and applications of lock-in carrierographic image pixel brightness dependence on multi-crystalline Si solar cell efficiency and photovoltage

Statistical theory and applications of lock-in carrierograph...

引用

作者： Mandelis, Andreas Zhang, Yu Melnikov, Alexander Mechanical and Industrial Engineering University of Toronto Toronto ON M5S 3G8 Canada Department of Automation Measurement and Control Harbin Institute of Technology Harbin 150001 China

A solar cell lock-in carrierographic image generation theory based on the concept of non-equilibrium radiation chemical potential was developed. An optoelectronic diode expression was derived linking the emitted radiative recombination photon flux (current density), the solar conversion efficiency, and the external load resistance via the closed- and/or open-circuit photovoltage. The expression was shown to be of a structure similar to the conventional electrical photovoltaic I-V equation, thereby allowing the carrierographic image to be used in a quantitative statistical pixel brightness distribution analysis with outcome being the non-contacting measurement of mean values of these important parameters averaged over the entire illuminated solar cell surface. This is the optoelectronic equivalent of the electrical (contacting) measurement method using an external resistor circuit and the outputs of the solar cell electrode grid, the latter acting as an averaging distribution network over the surface. The statistical theory was confirmed using multi-crystalline Si solar cells. © 2012 American Institute of Physics.

关键词： Pixels

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：