中国科学院机构知识库网格系统: 检索

Terahertz planar waveguide devices based on graphene 期刊论文 OAI收割
MODERN PHYSICS LETTERS B, 2017, 卷号: 31, 期号: 5, 页码: 1-6
作者: Yuan, Yizhe; Guo, Xiaoyong; An, Liqun; Xu, Wen

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Thz Waveguide Graphene Linear Dispersion Planar Structure Transmission Characteristics

Transmission Characteristics of Different Students during a School Outbreak of (H1N1) pdm09 Influenza in China, 2009 期刊论文 OAI收割
SCIENTIFIC REPORTS, 2014, 卷号: 4, 期号: 1, 页码: 1-8
作者: Wang, Ligui; Chu, Chenyi; Yang, Guang; Hao, Rongzhang; Li, Zhenjun

收藏 | 浏览/下载：53/0 | 提交时间：2015/08/12

transmission characteristics dynamic modeling pdm09 influenza outbreak school

Design of high speed and parallel compression system used in the big area CCD of high frame frequency (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Precision Engineering and Non-Traditional Machining, PENTM 2011, December 9, 2011 - December 11, 2011, Xi'an, China
作者: Li G.-N.; Jin L.-X.; Zhang R.-F.; Wang W.-H.; Li G.-N.

收藏 | 浏览/下载：55/0 | 提交时间：2013/03/25

According to the area CCD camera of characteristics such as high resolution capacity and high frame frequency this paper puts forward a high speed and parallel image compression system of high integration degree. Firstly according to the work principle of the area CCD FPGA is adopted to realize the timing driving and multichannel and parallel analog signal handling to raise the export frame frequency of the area CCD. Secondly with an image compression scheme based on FPGA embedded processor MicroBlaze and ADV212 compression chip real time image compression and the high speed area CCD are realized. Finally by detecting the analog signal of the area CCD output the real time compression of the big area CCD image is carried out in different compression ratios and the compression performance is analyzed. Experiment result shows that this scheme can realize real time image compression with the biggest data rate of 520Mbps. When compression bit ratio is 0.15 the signal-to-noise ratio of peak value can reach 36 dB. Image collection and image compression are integrated which reduces the data transmission between them and improves systematic integration degree.

An advanced LEO satellite network model based on MPLS-TP (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Advanced Intelligence and Awareness Internet, AIAI 2010, October 23, 2010 - October 25, 2010, Beijing, China
作者: Zhang Y.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

LEO (Low Earth Orbit) satellite networks are capable of providing broadband access to end users in any part of the world. With the characteristics of high-speed movement and rapid dynamic topology of LEO satellites networking has always been one of the key issues in LEO satellite network. MPLS-TP (Multi-Protocol Label Switching-Transport Profile) is an excellent packet transport network (PTN) technology in terrestrial networks which can support multi-service and have perfect function of QoS (Quality of Service) OAM (Operation Administration Maintenance) and survivability. In this paper the characteristics of LEO satellite network and functional architecture of MPLS-TP are introduced. Then an advanced LEO satellite network model based on MPLS-TP (ALSN-M) is proposed which can guarantee a connection-oriented seamless data transmission. Furthermore topology and routing algorithms of proposed LEO satellite network model is analyzed. In the end the paper describes how to setup and remove a LSP (Label Switched Path) and how to maintain an exiting LSP when a handover happens.

Application of precision harmonic gear drive in focusing mechanism of space camera (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Smart Structures and Materials in Manufacturing and Testing, April 26, 2010 - April 29, 2010, Dalian, China
作者: Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

A kind of precision harmonic gear drive in the focusing mechanism of space camera is studied which adopt external meshing complex wave transmission mode. Wave generator is combined with an elliptic cam and a flexible bearing around it. Flexspline is a structure of single wave with the same teeth. The output shaft is supported by a single cross-roller bearing. Ball screws connected the output shaft translate the rotational motion to the linear motion and drive the focusing mirror repeated moving along the linear guide. The output rigid wheel is connected with absolute encoder to detect displacement of focusing movement. It has the characteristics of big transmission ratio high precision compact structure high efficiency and smooth running etc. According to the practical application of this harmonic gear drive in the space camera the location relationship between the displacement of focusing structure and the focal plane movement is derived and the system error is analyzed its accuracy is tested with the open-loop control method. Experimental results show that transmission ratio of the instrument is 1:70 repeated positional accuracy is 2m which meet the requirements for use. 2010 SPIE.

Design and analysis of power system of micro-electromechanical actuator (EI CONFERENCE) 会议论文 OAI收割
2010 2nd International Conference on Industrial Mechatronics and Automation, ICIMA 2010, May 30, 2010 - May 31, 2010, Wuhan, China
作者: Zhang J.; Zhang J.; Zhang J.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

In order to apply the electromechanical actuator to tactical mini-missiles maximum rotational speed of output shafts is greater than 250/s. Test results basically correspond to the requirement of technical indexes. It is proved that this analysis and design method is congruent with the design of micro-electromechanical actuators this paper researches on the key technology such as load-bearing ability the system bandwidth can reach 25.3Hz on the condition of no load and 23.4Hz on the condition of load thus the method is feasible. 2010 IEEE. rapidity and miniaturization of the micro-electromechanical actuator power system based on the ball screw. First according to specific technical indexes the power electromechanical time constant and the size of the motors are screened originally through theoretical analysis. Finally based on the characteristics of ball screw transmission load locus of the micro-electromechanical actuator dynamic system is theoretically analyzed and the optimum speed ratio is determined through parameter optimization. The results of the double closed loop controlled test on the principle prototype show: the system can operate normally with 2.5N.m hinge moment

A high-accuracy parameter estimation algorithm for jointless Frequency-shift track circuit (EI CONFERENCE) 会议论文 OAI收割
ISECS International Colloquium on Computing, Communication, Control, and Management, CCCM 2008, August 3, 2008 - August 4, 2008, Guangzhou, China
作者: Zheng X.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

FSK (Frequency Shift keying) signal which has advantages of narrow-bandwidth strong anti-interference ability long transmission distance and so on is used in jointless Frequency-shift track circuit to send different kinds of control signals. However as FSK is non-linearly modulated parameter estimation with high accuracy is hard to realize. Based on the spectrum analysis complement with time-frequency distribution a highaccuracy FSK signal parameter estimation algorithm is put forward in this paper. According to the signal characteristics under-sampling and ZFFT are used to improve the accuracy of spectrum analysis and the base frequency resolution meets system requirement of 0.02Hz. Wigner-Ville distribution has an excellent time-frequency concentration while serious cross-term interference at the same time. Through the design of kernel function the cross-terms are almost suppressed and the upper/down side frequency resolution meets the system requirement of 0.2Hz. The effectivities of all the methods mentioned above have been proved by MATLAB simulation which pave a solid way for the development of high-accuracy FSK signal parameter estimation devices. 2008 IEEE.

The synthesis and field emission property of carbon nanotubes on carbon fibers substrate (EI CONFERENCE) 会议论文 OAI收割
Technical Digest of the 20th International Vacuum Nanoelectronics Conference, IVNC 07, July 8, 2008 - July 12, 2008, Chicago, IL, United states
Leyong Z.; Weibiao W.; Jingqiu L.; Yuxue X.; Da L.; Song C.; Haifeng Z.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

Using ferrocene as catalyst precursor C2H2 as carbon source carbon nanotubes (CNTs) with uniform density were synthesized on carbon fibers substrate by floating catalyst method. The morphology and microstructure were characterized by field emission scanning electron microscope (FESEM) and high-resolution transmission electron microscopy (HRTEM). The observation showed that the length of CNTs is about 2 m the average space between adjacent CNTs is about 300 nm and the diameter of CNT is about 45 nm. The less dense "short and stubby" aligned CNTs films should have good electron field emission characteristics. The results of field emission showed that the emission current of CNTs/carbon fibers was 5 A at the field of 2.5 V/m and the emission current can be 280 A with a field of 7 V/m (the specimen area is 0.25 cm2 and the distance between cathode and anode is 200 m). The calculation based on the F-N plot indicated that the field enhancement factor of CNTs tip is 499122. Using the conductivity and chemical stability of carbon fibers and the uniform and sparse density distribution of CNTs on carbon fibers substrate the tip predominance of carbon nanotubes can be exerted and simultaneously the effect of screening effects between adjacent carbon nanotubes on the field emission performance can also be effectively decreased. The CNTs synthesized on carbon fibers substrate has many predominances for the fabrication of cold cathode devices. For example using the removability of carbon fibers the cathode of CNTs/carbon fibers can be arbitrarily moved enlaced or combined to form different patterns and the cathode of CNTs/carbon fibers can be also fabricated in large size. Therefore CNTs/carbon fibers may have potential application in field emission displays.

Experimental researches on the one-dimensional photonic crystal microcavity (EI CONFERENCE) 会议论文 OAI收割
ICO20: Materials and Nanostructures, August 21, 2005 - August 26, 2005, Changchun, China
作者: Yu H.; He X.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

In experiments the energy band structures of one-dimensional photonic crystal (1-D PC) is researched. We get the relation between the band gap width and the number of the layers the dielectric indices contrast the center wavelength. The microcavity of 1-D PC is made. We study the reflection and transmission characteristics of the microcavity. Experimental results indicate the microcavity of 1-D PC can get a high reflection coefficient and a good stability and substantiality of the membrane layers in air.

Calculation of transmission efficiency and output characteristics for Beijing synchrotron radiation facility (BSRF) 3B3 beamline 期刊论文 OAI收割
HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION, 2006, 卷号: 30, 期号: 4, 页码: 359-363
作者: Zhao J(赵佳); Cui MQ(崔明启); Zhao YD(赵屹东); Zhao, J; Cui, MQ

收藏 | 浏览/下载：26/0 | 提交时间：2016/06/27

synchrotron radiation bend magnet beamline transmission efficiency output characteristics