检索结果-内蒙古大学图书馆

34-fs pulse generation directly from an Er:fiber laser

34-fs pulse generation directly from an Er:fiber laser

The 5th International Symposium on Ultra-fast Phenomena & Terahertz Waves(第五届超快现象与太赫兹波国际研讨会)

作者： Ding Ma Chun Zhou Yue Cai Weijian Zong Zhigang Zhang Institute of Quantum Electronics State Key Laboratory of Advanced Optical Communication System and NetworksSchool of Electronics Engineering and Computer Science University of Beijing Beijing 100871 P.R.China

We report 34 fs level pulse generation directly from a mode locked Er:fiber laser at a repetition rate of 230 MHz.

关键词： Ultrafast lasers Fiber lasers

来源：评论

学校读者我要写书评

暂无评论

Four-level superradiant laser with full atomic cooperativity

引用

Physical Review A 2010年第5期81卷 053809-053809页

作者： Deshui Yu Jingbiao Chen Department of Applied Physics Graduate School of Engineering The University of Tokyo Bunkyo-ku Tokyo 113-8656 Japan Institute of Quantum Electronics and State Key Laboratory of Advanced Optical Communication System & Network School of Electronics Engineering & Computer Science Peking University Beijing 100871 People's Republic of China State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai 200062 People's Republic of China

We investigate a four-level superradiant laser whose intensity is proportional to N2 and whose linewidth scales as 1/N2. In the absence of spontaneous emissions, we derive the stationary solutions of the atomic full cooperativity, analyze their stabilities, and find the corresponding irreducible representation based on group U(4). We also investigate the spectra of the phase and amplitude fluctuations of the fields inside and outside the cavity and find that the amplitude fluctuations of the output fields cannot be squeezed in the low-frequency limit, which is completely different from the three-level superradiant laser system. Finally, we consider the stationary solutions corresponding to the partial cooperativity due to the symmetry breaking of U(4) induced by the atomic spontaneous emissions.

关键词： Spontaneous emission

来源：评论

学校读者我要写书评

暂无评论

Fuzzy dynamic characteristic modeling and intelligent adaptive control for complex spacecraft

Fuzzy dynamic characteristic modeling and intelligent adapti...

引用

World Congress on Intelligent Control and Automation (WCICA)

作者： Xiong Luo Song Hu Zengqi Sun Xintao Qiu School of Information Engineering Key Laboratory of Advanced Control of Iron and Steel Process (Ministry of Education) University of Science and Technology Beijing Beijing China State Key Laboratory of Intelligent Technology and System Department of Computer Science and Technology Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing China

Because of strong coupling, nonlinear, and time-varying characteristics, it is difficult to control complex spacecraft. By means of combining with controlled object dynamics and performance requirements, characteristic modeling and control approach is an effective way to solve this problem. Aimed at the flexible satellites described by using characteristic modeling approach, with the help of fuzzy rules, fuzzy dynamic characteristic modeling method and intelligent adaptive controller are designed to control this complex spacecraft. Meanwhile, based on the satellite system simulation platform, we validate the correctness and efficiency of the proposed modeling and control method by comparing with the simulation results of the other similar methods.

关键词： Adaptation model Laboratories Satellites Space vehicles Intelligent control Artificial intelligence Information science

来源：评论

学校读者我要写书评

暂无评论

Dynamic modeling and tracking control of fuel filled space robotic system with flexible manipulators

Dynamic modeling and tracking control of fuel filled space r...

引用

International Symposium on systems and Control in Aerospace and Astronautics (ISSCAA)

作者： Xinxin Yang Xiong Luo Fuchun Sun Fengge Wu Huaping Liu School of Information Engineering Key Laboratory of Advanced Control of Iron and Steel Process (Ministry of Education) University of Science and Technology Beijing Beijing China State Key Laboratory of Intelligent Technology and System Department of Computer Science and TechnologyTsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing China

In recent years, dynamics model and control of space robot system are the hot topics in the research field. In this paper, a new dynamics model and control strategy of space robotic system with a flexible manipulator and a liquid fuel tank are investigated. Based on Lagrange equation method, the dynamics model of the space robotic system coupling with liquid sloshing, flexibility vibration and base movement is derived. The elastic deflection of the flexible manipulator is described by the assumed mode method and equivalent mechanical model is adopted instead of liquid sloshing under the environment of low-gravity. The inverse dynamics control algorithm combined with PD control method is performed to solve the trajectory tracking problem. Some simulation results are given to verify the effectiveness of the proposed method.

关键词： Mathematical model Aerospace electronics Manipulator dynamics Equations Space vehicles

来源：评论

学校读者我要写书评

暂无评论

A model for THz silicon nanotube transistor

A model for THz silicon nanotube transistor

引用

IEEE International Nanoelectronics Conference (INEC)

作者： Guangcun Shan Miao Zhang Wei Huang State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Micro System and Information Technology Shanghai China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy and Sciences Shanghai China Institute of Advanced Materials Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9781424435432

In this work, a schematic model of single-walled silicon nanotube (SWSiNT) devices is presented aimed at advancing the understanding of nano-electronic field. The circuit model of one-dimensional SWSiNT devices is firstly proposed. The cutoff frequency of SWSiNT devices is obtained, opening up the possibility of a THz silicon nanotube transistor.

关键词： Silicon Nanoscale devices Carbon nanotubes Mechanical factors Stability Organic materials Semiconductivity Temperature Microwave transistors Chemical technology

来源：评论

学校读者我要写书评

暂无评论

All-optical wavelength conversion based on four-wave mixing in silicon waveguides

All-optical wavelength conversion based on four-wave mixing ...

引用

9th International Conference on Optical Communications and Networks (ICOCN 2010)

作者： Shiming Gao Zhiqiang Li Yanqiao Xie Qiang Liu Xingzhi Zhang Yaocheng Shi Sailing He En-Kuang Tien Ozdal Boyraz Centre for Optical Electromagnetic Research State Key Laboratory of Modern Optical Instrumentation University of Zhejiang Hangzhou China Advanced Photonics Device and System Laboratory Department of Electrical Engineering and Computer Science University of California Irvine Irvine CA USA

All-optical wavelength conversion is investigated using four wave mixing in silicon waveguides. The influences of nonlinear losses caused by two-photon absorption (TPA) and TPA-induced free-carrier absorption on the conversion efficiency and phase-matching condition are analyzed. The conversion bandwidth is tempted to enhance by optimizing the waveguide geometry and using the two-pump regime. And finally an angled-polarization pump is used to realize the polarization-independent wavelength conversion by eliminating the polarization discrepancy between the TE and TM modes.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Software implementation of bar tacker control system

Software implementation of bar tacker control system

引用

GCIS, WRI Global Congress on Intelligent systems

作者： Cui Ma Xiaohui Xie Qiang Sun R. Du Shenzhen Institutes of Advanced Technology Chinese Academy and Sciences Shenzhen China State Key Laboratory of Robotics and System Harbin Institute of technology Harbin Heilongjiang China Chinese University of Hong Kong Hong Kong China

This paper presents a multi-axis control system of bar tacker. A bar tacker must meet the following requirements: feeding accurately, cutting automatically, needle stopping precisely and quickly, et ac. In order to achieve these functions, multi-thread synchronization control was introduced to ensure the multi-axis collaborative motion. And time-based PI method with velocity feed-forward was used to control the needle stop position. The software of this control system was programmed based on embedded Windows platform. At present this control system has been tested in the factory and the test results show that this method can accurately control the multi-axis motion and produce good sewing patterns. Besides lockstitch bar tacker, this control system can also be applied to other intelligent sewing machines by minor changes and improvement.

关键词： Servomotors Needles Position control Instruction sets Pi control Collaboration

来源：评论

学校读者我要写书评

暂无评论

An evaluation of PSO-type swarm robotic search: Modeling method and controlling properties

An evaluation of PSO-type swarm robotic search: Modeling met...

引用

2010 International Conference on Networking, Sensing and Control, ICNSC 2010

作者： Liu, Zhiqi Xue, Songdong Zeng, Jianchao Zhao, Jing Zhang, Guoyou State Key Lab. of Gansu Advanced Non-Ferrous Metal Materials Lanzhou University of Technology Lanzhou Gansu 730050 China Mechanical and Electronic Engineering College Taiyuan University of Science and Technology Taiyuan Shanxi 030024 China Complex System and Computational Intelligence Laboratory Taiyuan University of Science and Technology Taiyuan Shanxi 030024 China College of Electrical and Information Engineering Lanzhou University of Technology Lanzhou Gansu 730050 China

ISBN: (纸本)9781424464531

To show the validity of swarm robots modeling and control properties influenced by resulting algorithmic parameter settings, particle swarm optimization (PSO) is extended to be tools for applying to swarm robotic search applications. For this end, a series of experimental simulations are conducted and the effects of key algorithmic parameters, i.e., communication range, detection radius, and swarm size emerge from the statistical results. In such control architecture, swarm robots are modeled at an abstract level with the extended PSO and each individual is assumed to be controlled under three-state finite state machine mechanism. Simulation results indicate the validity of modeling method. Besides, significant positive correlations between search efficiency and communication range, detection radius as well as swarm size are also found. ©2010 IEEE.

关键词： Swarm intelligence

来源：评论

学校读者我要写书评

暂无评论

An interventional treatment plan system design on liver tumor

An interventional treatment plan system design on liver tumo...

引用

International Conference on Image Analysis and Signal Processing, IASP

作者： Xie Xiaohui Zhang Lei Yu Xiaofang Du Ruxu Shenzhen Institute of Advanced Integration Technology Chinese University of Hong Kong Shenzhen Hong Kong China State Key Laboratory of Robotics and System (HIT) Harbin Institute of Science and Technology Harbin China ShenZhen People's Hospital Shenzhen China

Interventional treatment becomes increasingly popular since this technique means substantially less trauma for the patient. By using VTK and ITK to build a plan system, the treatment can be high efficiency. VTK is responsible for visualization, while ITK takes care of the image segmentation and registration. By combining VTK and ITK, and using Qt as the user interface, an interventional treatment plan system is built. This system has finished several mainly functions, like DICOM data displaying in multi-planar reformation, manual segmentation, semi-automatic segmentation, surface rendering using marching cubes algorithm, volume rendering using volume ray casting algorithm. Also an interventional treatment plan system has been developed based on the medical inspection.

关键词： Liver neoplasms Image segmentation Medical treatment Rendering (computer graphics) Data visualization User interfaces DICOM Surface finishing Surface treatment Casting

来源：评论

学校读者我要写书评

暂无评论

Shannon Entropy and Kurtosis Analyses of Ultrasonic Wave Signals from Active Sensor Network for Damage Identification in Composite Structures

Shannon Entropy and Kurtosis Analyses of Ultrasonic Wave Sig...

引用

第七届亚澳复合材料会议

作者： Lin Ye Dong Wang Ye Lu Fucai Li Centre for Advanced Materials Technology (CAMT) School of AerospaceMechanical and Mechatronic EngineeringThe University of SydneyNSW 2006Australia State Key Laboratory of Mechanical System and VibrationShanghai Jiao Tong UniversityShanghai 200030People''s Republic of China

This study investigates the effects of temperature fluctuation on identification of damage in complex composite structures, using an inverse algorithm based on interrogation using Shannon entropy or kurtosis analysis of captured Lamb wave *** method uses mapping of damage signatures from individual sensing (actuator-sensor) paths to the probability values for the presence of damage at individual grids in the monitoring area enclosed by the piezoelectric actuator/sensor network.

关键词： Damage imaging Structural health monitoring Ultrasonic waves Temperature effect Composite structures

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：