期刊文献+
共找到60篇文章
< 1 2 3 >
每页显示 20 50 100
RESEARCH ON THE PACKING ALGORITHM FOR ANTI-SEU OF FPGA BASED ON TRIPLE MODULAR REDUNDANCY AND THE NUMBERS OF FAN-OUTS OF THE NET
1
作者 Cui Xiuhai Yang Haigang +1 位作者 Peng Yu Peng Xiyuan 《Journal of Electronics(China)》 2014年第4期284-289,共6页
Static Random Access Memory(SRAM) based Field Programmable Gate Array(FPGA) is widely applied in the field of aerospace, whose anti-SEU(Single Event Upset) capability becomes more and more important. To improve anti-F... Static Random Access Memory(SRAM) based Field Programmable Gate Array(FPGA) is widely applied in the field of aerospace, whose anti-SEU(Single Event Upset) capability becomes more and more important. To improve anti-FPGA SEU capability, the registers of the circuit netlist are tripled and divided into three categories in this study. By the packing algorithm, the registers of triple modular redundancy are loaded into different configurable logic block. At the same time, the packing algorithm considers the effect of large fan-out nets. The experimental results show that the algorithm successfully realize the packing of the register of Triple Modular Redundancy(TMR). Comparing with Timing Versatile PACKing(TVPACK), the algorithm in this study is able to obtain a 11% reduction of the number of the nets in critical path, and a 12% reduction of the time delay in critical path on average when TMR is not considered. Especially, some critical path delay of circuit can be improved about 33%. 展开更多
关键词 Field Programmable Gate Array (FPGA) Triple Modular Redundancy (TMR) Packing algorithm Fan-outs of the net Critical path delayCLC number:TN473
下载PDF
热力羽流的大涡模拟 被引量:2
2
作者 杨小龙 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2008年第7期36-40,共5页
采用大涡模拟的方法对两无穷大平板间受热形成的羽流进行了数值模拟.控制方程为三维不可压N-S方程组,数值格式采用了高精度的伪谱方法,亚格子模型则采用了TNS模型.首先对槽道流进行了模拟,通过比较大涡模拟和直接数值模拟的结果对此方... 采用大涡模拟的方法对两无穷大平板间受热形成的羽流进行了数值模拟.控制方程为三维不可压N-S方程组,数值格式采用了高精度的伪谱方法,亚格子模型则采用了TNS模型.首先对槽道流进行了模拟,通过比较大涡模拟和直接数值模拟的结果对此方法进行了验证.随后数值模拟了热力羽流的输运过程,分析讨论了相关的温度场和速度场,并比较了不同Rayleigh数对流动特性的影响.结果表明当Rayleigh数比较大时,热浮力对流动的影响比较大,形成了比较复杂的流动结构. 展开更多
关键词 大涡模拟 TNS模型 羽流 Rayleigh数
下载PDF
罗江县农田土壤全氮协同克里格插值和采样数量优化研究 被引量:3
3
作者 郭鑫 《安徽农业科学》 CAS 2012年第5期2756-2760,共5页
[目的]研究县域土壤全氮含量的空间分布和采样数量,为紫色土丘陵区采样提供参考。[方法]利用协同克里格法,以初始的1 777个土壤全氮含量数据为随机抽取的数据,分别随机抽取1 599、1 421和1 243个数据为目标变量,并以初始的1 777个土壤... [目的]研究县域土壤全氮含量的空间分布和采样数量,为紫色土丘陵区采样提供参考。[方法]利用协同克里格法,以初始的1 777个土壤全氮含量数据为随机抽取的数据,分别随机抽取1 599、1 421和1 243个数据为目标变量,并以初始的1 777个土壤有机质数据为辅助变量,对四川省罗江县土壤全氮含量进行插值分析,从而利用协同克里格法对县域尺度下农田土壤全氮含量在不同样点数量下空间分布中的适用性进行评价。[结果]在相同取样数量下,全氮协同克里格法的均方根误差相对于普通克里格法降低0.019 6%~0.072 5%,预测值和实测值之间的相关系数提高0.69%~0.90%。利用协同克里格法,土壤全氮含量数据在缩减30%情况下,其估值精度高于1 777个样点下的普通克里格估值,且二者的分布图都具有较高的拟合度。[结论]协同克里格法是一种经济、精准的方法,可为县域土壤养分含量的空间分布提供基础信息。 展开更多
关键词 县域 农田土壤 全氮 协同克里格法 采样数量
下载PDF
Comparison of Ge_xSi_(1- x) Grown by UHV/CVD from Si_2H_6/GeH_4 and SiH_4/GeH_4 被引量:1
4
作者 LI Dai-zong, YU Zhuo, CHEN Bu-wen, HUANG Chang-jun, LEI Zhen-lin, YU Jin-zhong, WANG Qi-ming (State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083,CHN) 《Semiconductor Photonics and Technology》 CAS 1999年第3期134-138,共5页
Using double crystal X-rays diffraction (DCXRD) and atomic force microscopy (AFM), the results of Ge x Si 1- x grown by UHV/CVD from Si 2H 6 and SiH 4 are analyzed and compared. Adsorbates can migrate to the energy-fa... Using double crystal X-rays diffraction (DCXRD) and atomic force microscopy (AFM), the results of Ge x Si 1- x grown by UHV/CVD from Si 2H 6 and SiH 4 are analyzed and compared. Adsorbates can migrate to the energy-favoring position due to the slow growth rate from SiH 4. In this case, a Si buffer that isolates the effect of substrate on epilayer could not be grown, which results in a pit penetrating into epilayer and buffer. The FWHM is 0.055° in DCXRD from SiH 4. The presence of diffraction fringes is an indication of an excellent crystalline quality. The roughness of the surface is improved if grown by Si 2H 6; however, the crystal quality of the Ge x Si 1- x material became worse than that from SiH 4 due to much larger growth rate from Si 2H 6. The content of Ge is obtained from DCXRD, which indicates the growth rate from Si 2H 6 is largest, then GeH 4, and that from SiH 4 is least. 展开更多
关键词 Semiconductor Materials GESI UHV/CVD CLC number:tn304.054 Document code:A
下载PDF
Optical and Electrical Properties of Sensitized Polyaniline by Electrochemical Polymerization 被引量:3
5
作者 WANG Hui,ZHENG Jian-bang,FENG Wei,WU Hong-cai (School of Electr. & Inform. Eng., Xi’an Jiaotong University, Xi’an 710049,CHN) 《Semiconductor Photonics and Technology》 CAS 1999年第3期156-160,共5页
To sensitize polyaniline with dyes by electrochemical polymerization, HClO 4 is employed as the dopant and oxidant, and the polyaniline with different sensitive properties is synthesized. The effect of sensitized emer... To sensitize polyaniline with dyes by electrochemical polymerization, HClO 4 is employed as the dopant and oxidant, and the polyaniline with different sensitive properties is synthesized. The effect of sensitized emeraldine salt on the absorption spectrum is discussed in details. The maximum conductivity of sensitized films reaches 1.22 S/cm, and investigation on dye sensitizing of the polymer reveals that C.I. Direct Blue 71, C.I. Direct Blue 84, C.I. Direct Black 19 and CuPc-(COOH) 4 may enhance the photoconductivity of polyaniline greatly. 展开更多
关键词 Electrochemical Polymerization Dye Photoconductive Polymer Sensitizing CLC number:O631.23 O632.7 TN304.52 Document code:A
下载PDF
INDEPENDENTLY-TUNED CONCURRENT DUAL-BAND BRANCH-LINE COUPLER USING VARACTOR 被引量:1
6
作者 Guo Xiaofeng Ye Yan +2 位作者 Liu Taijun Xu Qian Li Ruiyang 《Journal of Electronics(China)》 2014年第4期348-353,共6页
This paper presents a concurrent dual-band branch-line coupler with an independently tunable center frequency. In the proposed architecture, the quarter-wavelength lines, which work at two separated bands concurrently... This paper presents a concurrent dual-band branch-line coupler with an independently tunable center frequency. In the proposed architecture, the quarter-wavelength lines, which work at two separated bands concurrently and can be tuned in one of them, are key components. Based on the analysis of ABCD-matrix, a novel hybrid structure and a pair of varactors topology are utilized to achieve concurrent dual-band operation and independent tunability, respectively. Using this configuration, it is convenient to tune the center frequency of the upper band, while the responses of the lower band remain unaltered. To verify the proposed idea, a demonstration is implemented and the simulated results are presented. 展开更多
关键词 Branch-line coupler Concurrent dual-band VARACTOR Independently tuned Quarter-wavelength lineCLC number:TN92
下载PDF
Optical Fiber Displacement Sensor with Ultra-high Resolution 被引量:1
7
作者 CAI Shu-lan (Yanshan University, Qinhuangdao 066004,CHN) 《Semiconductor Photonics and Technology》 CAS 1999年第2期101-105,共5页
A low fineness fiber optic Fabry-Perot interferometric displacement sensor has been developed and tested.A 0.005 nm displacement resolution is obtained by using He-Ne laser with a high performance ,photodetectors with... A low fineness fiber optic Fabry-Perot interferometric displacement sensor has been developed and tested.A 0.005 nm displacement resolution is obtained by using He-Ne laser with a high performance ,photodetectors with low noise ,low drift operational amplifiers,6-pole Butterworth filters and perfect digital signal processing circuits. 展开更多
关键词 Displacement Sensor INTERFEROMETER Optical Fiber CLC number:TN253 TP212 Document code:A
下载PDF
QUANTUM COLLISION SEARCH ALGORITHM AGAINST NEW FORK-256 被引量:1
8
作者 Du Fangwei Wang Hong Ma Zhi 《Journal of Electronics(China)》 2014年第4期366-370,共5页
In order to improve the attack efficiency of the New FORK-256 function, an algorithm based on Grover's quantum search algorithm and birthday attack is proposed. In this algorithm, finding a collision for arbitrary... In order to improve the attack efficiency of the New FORK-256 function, an algorithm based on Grover's quantum search algorithm and birthday attack is proposed. In this algorithm, finding a collision for arbitrary hash function only needs O(2m/3) expected evaluations, where m is the size of hash space value. It is proved that the algorithm can obviously improve the attack efficiency for only needing O(2 74.7) expected evaluations, and this is more efficient than any known classical algorithm, and the consumed space of the algorithm equals the evaluation. 展开更多
关键词 Quantum computation Quantum collision Grover's search algorithm New FORK-256CLC number:TN918.1
下载PDF
DOWNWARD LOOKING SPARSE LINEAR ARRAY 3D SAR IMAGING ALGORITHM BASED ON BACK-PROJECTION AND CONVEX OPTIMIZATION 被引量:1
9
作者 Bao Qian Peng Xueming +2 位作者 Wang Yanping Tan Weixian Hong Wen 《Journal of Electronics(China)》 2014年第4期298-309,共12页
Downward Looking Sparse Linear Array Three Dimensional SAR(DLSLA 3D SAR) is an important form of 3D SAR imaging, which has a widespread application field. Since its practical equivalent phase centers are usually distr... Downward Looking Sparse Linear Array Three Dimensional SAR(DLSLA 3D SAR) is an important form of 3D SAR imaging, which has a widespread application field. Since its practical equivalent phase centers are usually distributed sparsely and nonuniformly, traditional 3D SAR algorithms suffer from low resolution and high sidelobes in cross-track dimension. To deal with this problem, this paper introduces a method based on back-projection and convex optimization to achieve 3D high accuracy imaging reconstruction. Compared with traditional SAR algorithms, the proposed method sufficiently utilizes the sparsity of the 3D SAR imaging scene and can achieve lower sidelobes and higher resolution in cross-track dimension. In the simulated experiments, the reconstructed results of both simple and complex imaging scene verify that the proposed method outperforms 3D back-projection algorithm and shows satisfying cross-track dimensional resolution and good robustness to noise. 展开更多
关键词 Three Dimensional SAR (3D SAR) Downward looking Sparse linear array Convex optimizationCLC number:TN957
下载PDF
NEW SAR IMAGE INTERPRETATION METHOD OF AIRCRAFT BASED ON JOINT TIME-FREQUENCY ANALYSIS 被引量:1
10
作者 Zhu Jiwei Qiu Xiaolan Lei Bin 《Journal of Electronics(China)》 2014年第4期325-333,共9页
With the continuous improvement of Synthetic Aperture Radar(SAR) resolution, interpreting the small targets like aircraft in SAR images becomes possible and turn out to be a hot spot in SAR application research. Howev... With the continuous improvement of Synthetic Aperture Radar(SAR) resolution, interpreting the small targets like aircraft in SAR images becomes possible and turn out to be a hot spot in SAR application research. However, due to the complexity of SAR imaging mechanism, interpreting targets in SAR images is a tough problem. This paper presents a new aircraft interpretation method based on the joint time-frequency analysis and multi-dimensional contrasting of basic structures. Moreover, SAR data acquisition experiment is designed for interpreting the aircraft. Analyzing the experiment data with our method, the result shows that the proposed method largely makes use of the SAR data information. The reasonable results can provide some auxiliary support for the SAR images manual interpretation. 展开更多
关键词 Synthetic Aperture Radar (SAR) image interpretation Joint time-frequency analysis Scattering centers Basic structureCLC number:TN957
下载PDF
通信及控制系统设备中的电磁兼容设计方法 被引量:3
11
作者 莫世禹 《环境技术》 2008年第6期50-55,共6页
本文介绍通信及控制系统设备的电磁兼容设计方法;包括电路设计、印制板设计、设备内部走线设计、屏蔽设计、滤波及接地设计等的电磁兼容设计。
关键词 EMC(电磁兼容) EMI(电磁干扰) 电磁干扰源 耦合途径 敏感设备
下载PDF
Influence on Conductivity of Polyparaphenylene by Chemical Doping and Ion Implantation 被引量:1
12
作者 WANG Hui, WU Hong-cai (School of Electron. & Inform. Eng., Xi’an Jiaotong University, Xi’an 710049,CHN) 《Semiconductor Photonics and Technology》 CAS 1999年第2期114-118,共5页
Polyparaphenylene(PPP) is prepared by AlCl 3-CuCl 2 catalysts with benzene as the monomer and is doped by chemical method and N + ion implantation. The influences of the concentration, temperature and time of chemi... Polyparaphenylene(PPP) is prepared by AlCl 3-CuCl 2 catalysts with benzene as the monomer and is doped by chemical method and N + ion implantation. The influences of the concentration, temperature and time of chemical doping and the dose, energy and temperature of ion implantation, on PPP conductivity are investigated. The results showed that the conductivity of PPP can be improved 4~5 orders of magnitude by ion implantation and the conductivity of PPP can reach about 0.11 S·cm -1 by chemical doping. The comparison of stability of the material conductive behavior by using the two doping methods is presented. It shows that ion implantation is better than chemical doping in stabilizing the electric conductive behavior for the material. 展开更多
关键词 Conducting Polymers Ion Implantation Polyparaphenylene CLC number:O 631.23 O 632.7 TN304.52 Document code:A
下载PDF
MOTION COMPENSATION USING SUBSTRIP PGA 被引量:1
13
作者 Zhang Lei Liu Yabo Yang Liang 《Journal of Electronics(China)》 2014年第4期317-324,共8页
MOtion COmpensation(MOCO) is an essential step in high resolution airborne Synthetic Aperture Radar(SAR) imaging. Generally, a reference altitude level is assumed and external Digital Elevation Model(DEM) is required ... MOtion COmpensation(MOCO) is an essential step in high resolution airborne Synthetic Aperture Radar(SAR) imaging. Generally, a reference altitude level is assumed and external Digital Elevation Model(DEM) is required for the scene topography heavily varied. To overcome the shortcoming, we propose a MOCO method based on Phase Gradient Autofocus(PGA) which can obtain well focused images without DEM. In the implementation, we first compensate the normal range-invariant term. Then the data are divided into strips in range-compressed domain and PGA is applied to each substrip to extract the phase errors. Finally, the phase error surface is obtained using interpolation and then compensated. Real airborne SAR data of a UAV-SAR system experiments and comparisons demonstrate the validity and effectiveness of the proposed algorithm. The results show that our algorithm is effective. 展开更多
关键词 Synthetic Aperture Radar (SAR) MOtion COmpensation (MOCO) Phase Gradient Autofocus (PGA)CLC number:TN957.52
下载PDF
Kravchenko probabilityweight functions in problems of radar signals correlation processing 被引量:3
14
作者 V F Kravchenko D V Churikov 《Journal of Measurement Science and Instrumentation》 CAS 2013年第3期231-237,共7页
In this report the combined method of correlation radar signal(RS)processing based on the theory of atomic functions(AF)is examined.Examples of using of new Kravchenko probability weight functions(WF)designs are prese... In this report the combined method of correlation radar signal(RS)processing based on the theory of atomic functions(AF)is examined.Examples of using of new Kravchenko probability weight functions(WF)designs are presented.Quality functional to estimate accuracy and efficiency of RS processing for concrete physical models is constructed.It is shown that the proposed approach significantly improves the quality of the coherent analysis of RS. 展开更多
关键词 radar signal (RS) atomic funtions (AF) weight functions (WF)CLC number:TN911.7 Document code:AArticle ID:1674-8042(2013)03-0231-07
下载PDF
AltBOC navigation signal quality assessment and measurement 被引量:1
15
作者 孟庆丰 焦国太 薛强强 《Journal of Measurement Science and Instrumentation》 CAS 2013年第3期289-293,共5页
In order to ensure that Chinese BeiDou satellite navigation system runs smoothly,the assessment of signal quality has become a significant task.Alternative binary offset carrier(AltBOC)is BeiDou B2 frequency signal.Th... In order to ensure that Chinese BeiDou satellite navigation system runs smoothly,the assessment of signal quality has become a significant task.Alternative binary offset carrier(AltBOC)is BeiDou B2 frequency signal.The acquisition of BeiDou signal is processed in off-line mode and the evaluation is performed by taking signal power spectrum,eye diagram,constellation,correlation,loss and s-curve deviation on AltBOC as signal quality evaluation parameters.The results illustrate that the new system signal,namely AltBOC signal,has the best performance in code tracking precision,anti-jamming and anti-multipath. 展开更多
关键词 TN911.7signal quality assessment alternative binary offset carrier(Alt-BOC) correlation loss s-curve biasCLC number:TN911.7 Document code:AArticle ID:1674-8042(2013)03-0289-05
下载PDF
Photoelectric Property of Polyaniline Doped with Organic Sulphonic Acid 被引量:1
16
作者 FENG Wei,WANG Hui, ZHENG Jian-bang, LI Cheng-quan,WEI Wei, WU Hong-cai (School of Electron. & Inform. Eng., Xi’an Jiaotong University, Xi’an 710049,CHN) 《Semiconductor Photonics and Technology》 CAS 1999年第2期119-124,共6页
Photoelectric property of polyaniline doped with dodecyl-benzene sulphonic acid (DBSA) is studied. The result shows that the concentration of carrier increases obviously, when polyaniline doped with DBSA is irradiated... Photoelectric property of polyaniline doped with dodecyl-benzene sulphonic acid (DBSA) is studied. The result shows that the concentration of carrier increases obviously, when polyaniline doped with DBSA is irradiated with light. Mixture of sensitive material is advantageous to the absorption of polyaniline in visible light spectrum, and the conductivity is also improved. The results of dielectric measurements on polyaniline doped with DBSA in an Al-PAn-DBSA-Al configuration as function of frequency and temperature are reported. The space-charge polarization phenomenon is observed. Carrier lifetime is microsecond magnitude and mobility is (0.001~0.1) cm 2/V·s, which are obtained by calculation or experiment. The active energy is obtained from the relation between conductivity and temperature. The conducting mechanism of PAn-DBSA is analyzed. 展开更多
关键词 Dielectric Relaxation Doping Photoelectric Functional Material Polyaniline Sensitive Dye CLC number:O 631.23 O 632.7 TN304.52 Document code:A
下载PDF
A new algorithm for wireless sensor network based on NS-2 被引量:2
17
作者 焦国太 孟庆丰 《Journal of Measurement Science and Instrumentation》 CAS 2013年第3期272-275,共4页
Considering wireless sensor network characteristics,this paper uses network simulator,version2(NS-2)algorithm to improve Ad hoc on-demand distance vector(AODV)routing algorithm,so that it can be applied to wireless se... Considering wireless sensor network characteristics,this paper uses network simulator,version2(NS-2)algorithm to improve Ad hoc on-demand distance vector(AODV)routing algorithm,so that it can be applied to wireless sensor networks.After studying AODV routing protocol,a new algorithm called Must is brought up.This paper introduces the background and algorithm theory of Must,and discusses the details about how to implement Must algorithm.At last,using network simulator(NS-2),the performance of Must is evaluated and compared with that of AODV.Simulation results show that the network using Must algorithm has perfect performance. 展开更多
关键词 wireless sensor networks routing protocol network simulator version 2 (NS-2) Must algorithmCLC number:TN926 Document code:AArticle ID:1674-8042(2013)03-0272-04
下载PDF
Wireless sensor network based on CC2530 被引量:1
18
作者 郭涛 闫明明 鲍爱达 《Journal of Measurement Science and Instrumentation》 CAS 2013年第3期286-288,共3页
This paper designs a wireless sensor network based on CC2530.The sensor nodes consist of multi-ranged accelerometer and CC2530,covering all the ranges of the acceleration signals which can be measured.The designed sys... This paper designs a wireless sensor network based on CC2530.The sensor nodes consist of multi-ranged accelerometer and CC2530,covering all the ranges of the acceleration signals which can be measured.The designed system solves the problems such as cable installation trouble of testing system,vulnerability to interference and complexity of circuit.Test results show that the designed wireless sensor network can transmit the signals that multi-ranged micro-accelerometer emits without spoilage,thus the measurement of acceleration of the covering region is completed. 展开更多
关键词 multi-ranged micro-accelerometer ACCELERATION wireless sensor networkCLC number:TN926 Document code:AArticle ID:1674-8042(2013)03-0286-03
下载PDF
NOVEL TWO-LAYER MOTION ESTIMATION FOR VIDEO CODING
19
作者 A.V.Paramkusam V.S.K.Reddy 《Journal of Electronics(China)》 2014年第4期354-365,共12页
In this paper, we proposed a novel Two-layer Motion Estimation(TME) which searches motion vectors on two layers with partial distortion measures in order to reduce the overwhelming computational complexity of Motion E... In this paper, we proposed a novel Two-layer Motion Estimation(TME) which searches motion vectors on two layers with partial distortion measures in order to reduce the overwhelming computational complexity of Motion Estimation(ME) in video coding. A layer is an image which is derived from the reference frame such that the sum of a block of pixels in the reference frame determines the point of a layer. It has been noticed on different video sequences that many motion vectors on the layers are the same as those searched on the reference frame. The proposed TME performs a coarse search on the first layer to identify the small region in which the best candidate block is likely to be positioned and then perform local refined search on the next layer to pick the best candidate block in the located small area. The key feature of TME is its flexibility of mixing with any fast search algorithm. Experimental results on a wide variety of video sequences show that the proposed algorithm has achieved both fast speed and good motion prediction quality when compared to well known as well as the state-of-the-art fast block matching algorithms. 展开更多
关键词 Motion Estimation (ME) Block matching algorithm MULTI-LAYER Fast search algorithmCLC number:TN911.73
下载PDF
NUMERICAL ANALYSIS OF CENTERED-INCLINED COUPLING SLOTS IN RECTANGULAR WAVEGUIDES
20
作者 Wang Xucun Zhou Yiguo Wang Yanfei 《Journal of Electronics(China)》 2014年第4期334-340,共7页
Numerical analysis is presented for the characteristic parameters of centered-inclined coupling slot in rectangular waveguides, taking into account the transverse distribution of the electric field across the slot ape... Numerical analysis is presented for the characteristic parameters of centered-inclined coupling slot in rectangular waveguides, taking into account the transverse distribution of the electric field across the slot aperture. Integral equations are formulated based on dyadic Green's function theories and solved using the method of moments. Trigonometric basis functions are adopted. It is found that the method will converge with up to ten basis functions. The characteristic parameters can be easily obtained for different slot sizes. Resonant length and resonant resistance of the coupling slots are calculated. It is shown that the calculated results have very high accuracy, compared with simulated results obtained from commercial software. Therefore, it can be effectively applied in the synthesis of antenna arrays. Effects of the transverse distribution on calculating resonant parameters of the coupling slot are also analyzed. The results show that if the transverse distribution of the electric field is neglected, the calculated error tends to become larger when the slot gets wider or thinner. 展开更多
关键词 Rectangular waveguide Centered-inclined coupling slot Moment method Transverse distributionCLC number:TN823
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部