摘要：
This paper presents a stepped electromagnetic bandgap(EBG) hosted on the T-shaped stepped stub with an inverted H-shaped slot etched on the ground to enhance bandwidth and improve isolation for a compact UWB-MIMO antenna developed from our previous design. The characteristic mode analysis is used to offer physical insight into the operation phenomena taking place in the evolution of antenna. The proposed antenna has a compact size of $27\times 22\times 0.8$ mm and realize bandwidth from 3.07 GHz to 11.1 GHz, keeping the isolation more than 20 dB. Key parameters evaluating the antenna performance like radiation pattern, gain, radiation efficiency above 75% and envelope correlation coefficient below 0.05 are investigated. The simulated and measured results agree well, testifying the proposed MIMO antenna is a suitable candidate for UWB applications.
关键词：
Composite scattering;hybrid method;target above the rough surface;KA-MoM method
摘要：
By combining Kirchhoff approximation (KA) with the method of moment (MOM), a hybrid method is proposed to solve the scattering problem of a dielectric target above a dielectric rough surface. The field on the rough surface can be represented by the tapered incident wave and the scattering field of the target as the secondary incident wave using Kirchhoff approximation. Then, the electric field integral equations of the induced current and magnetic current on the target are derived to solve the problem. The field of the rough surface can be directly obtained by the tapered incident wave and the current and magnetic current on the target surface. Therefore, compared with the traditional method of moments, the hybrid algorithm only needs to solve the electric field integral equation of the target. The simulation of bistatic scattering from a cylindrical target on a Gaussian rough surface is carried out, and the effectiveness and effectiveness of the method are verified.
会议论文集名称：
IOP Conference Series-Earth and Environmental Science
摘要：
As solar light was mainly absorbed by absorb layer in thin film solar cells, the quality of absorb layer has a great effect on the performance of solar cells. Based on the diffusion drift model of carrier in copper indium gallium selenide (CIGS) solar cells, and then the key parameters are analyzed. Combining with the experimental results of others, this paper discusses the absorption layer's thickness influence on the open circuit voltage, short circuit current, filling factor and conversion efficiency of the copper indium gallium selenium based solar cells. The results show that the absorption layer's thickness always affects the performance parameters of the battery. Open circuit voltage increased with increasing thickness and reached saturation above 2 mu m. Short circuit current increased first and then decreased, then reaches its maximum value at about 2 mu m thickness. Conversion efficiency is similar to the short circuit current properties. While the fill factor decreased with the increase of thickness above 1.2 mu m. This can provide theoretical support for the design of better device structures.
关键词：
The polarizing beam splitter;multimode interference coupler;Mach-Zehnder interference
摘要：
The polarizing beam splitter (PBS) based on asymmetric Mach-Zehnder (MZ) interferometer is described theoretically by means of transfer matrix. And the intensity formulas of the output port are obtained according to the theoretical description. The width and length of the PBS interference arm are determined by ways of theoretical calculation and simulation design, and it is found that the theoretical calculation is in good agreement with the simulation design results. The final simulation results show that the designed PBS has a good performance, and the extinction ratio is higher than 30dB in the whole C band. It is expected to realize polarization splitting function in optical fiber communication system. The asymmetric MZ PBS is expected to be widely used in optical fiber communication systems that require polarization splitting.
关键词：
Magnetic properties;nanoclusters;antiferromagnetic states;Fe doped
摘要：
Lowest energy structures of ZnnSen (n=2–13) nanoclusters were obtained as the pristine clusters with first principle all-electron calculations. Second-order energy difference of the Lowest energy ZnnSen (n=2–13) nanoclusters indicated that n=12 is the stable size. Then Zn12Se12 cluster were applied to be doped with single and two Fe atoms to investigate the structural and magnetic properties of Fe doped small ZnSe nanoclusters. Configuration of Fe doped Zn12Se12 were applied and total energy indicated that Fe atoms prefer to substitute Zn atoms in Fe-doped Zn12Se12 nanoclusters. And for the two Fe doped Zn12Se12 cluster, Fe atoms favor to locate at adjacent Zn atom sites in antiferromagnetic states because of the Fe–Fe short ranged superexchange mechanism, and energy gap between lowest unoccupied molecular orbital and the highest occupied molecular orbital were presented with Fe-Fe distance for the cluster with further light emitting exploring. REFERENCES Section: ChooseTop of pageREFERENCES << 1. S. Andrew. Crampton, D. Marian. RÖtzer, J. Claron. F. Ridge Florian. Schweinberger, Ueli Heiz, Bokwon Yoon, Uzi Landman, Structure sensitivity in the nonscalable regime explored via catalysed ethylene hydrogenation on supported platinum nanoclusters, Nature Communications. 7 (2016): 10389 https://doi.org/10.1038/ncomms10389, Google ScholarCrossref 2. N. Pradhan and X.-G. Peng, Efficient and Color-Tunable Mn-Doped ZnSe Nanocrystal Emitters: Control of Optical Performance via Greener Synthetic Chemistry, J. Am. Chem. Soc., 129 (2007): 3339–47. https://doi.org/10.1021/ja068360v, Google ScholarCrossref 3. Y. Lin, Z. Jianguo, X. Dingquan. Microemulsion-mediated hydrothermal synthesis of ZnSe and Fe-doped ZnSe quantum dots with different luminescence characteristics. Royal Society of Chemistry RSC Adv. 2 (2012): 8179–8188 https://doi.org/10.1039/c2ra21401f, Google ScholarCrossref 4. S. Jaspal, N.K. Verma. Synthesis and characterization of Fe-doped CdSe nanoparticles as dilute magnetic semiconductor. J Supercond Nov Magn 25 (2012):2425–2430, Google ScholarCrossref 5. M. K. Yadav, B. Sanyal and A. Mookerjee, Structural, Electronic and Magnetic Properties of Cr-Doped (ZnTe)12 Clusters, J. Magn.Magn. Mater. 321 (2009): 235–40. https://doi.org/10.1016/j.jmmm.2008.08.092, Google ScholarCrossref Published by AIP Publishing. false
会议论文集名称：
International Conference on Manipulation Manufacturing and Measurement on the Nanoscale
关键词：
Chemical Bath solution;ZnSe Films;Growth Kinetics;Optical Properties
摘要：
ZnSe nano thin films were obtained with chemical bath deposition in an modified aqueous alkaline solution in which ammonia was eliminated from the complexing agent in our present work. The as-deposited films are transparent, specula reflective and homogenous. Energy-dispersive X-ray spectroscopy indicated that films were in near stiochiometric Zn:Se ratio. Measured by spectroscopic ellipsometry, thickness of 50 similar to 370nm film can be obtained, the ZnSe were in nano-films, morphology and the film formation process discussion indicated that the film grow through nano-cluster by nano-cluster deposition rather than ion by ion mechanism. Absorption of the annealed films in visible light area indicated that bandgap is around 2.8eV for the annealed ZnSe film obtained from modified ammonia free solutions, corresponding to the standard band gap for bulk ZnSe materials.
摘要：
Large structure modal parameter estimation has always been an important research content. Its core content is to obtain the eigenvalues of large-scale structural system. Based on the environmental excitaion, to obtain high precision system free response is particularly important. This paper presents a random reduction de-noising-ARMA method(RDT-ARMA method). By analyzing the characteristics of free response root and imaginary part under the condition of health and damage, the noise modal of free response obtained by stochastic reduction method can be effectively eliminated to obtain a more realistic system free response signal. Based on this, the modal of large structural system is identified by ARMA method. And through the actual acquisition of the WSN signal processing measured acceleration, indicating the effectiveness of the proposed method can be proved.
期刊：
Proceedings - 2018 11th International Symposium on Computational Intelligence and Design, ISCID 2018,2018年2:380-384 ISSN：2165-1701
通讯作者：
Chen, Deshan
作者机构：
[Chen, Deshan] Wuhan Univ Technol, Natl Engn Res Ctr Water Transport Safety, Intelligent Transportat Syst Res Ctr, Wuhan 430063, Hubei, Peoples R China.;[Teng, XuanXuan] Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan, Hubei, Peoples R China.
通讯机构：
[Chen, Deshan] W;Wuhan Univ Technol, Natl Engn Res Ctr Water Transport Safety, Intelligent Transportat Syst Res Ctr, Wuhan 430063, Hubei, Peoples R China.
会议名称：
11th International Symposium on Computational Intelligence and Design (ISCID)
会议时间：
DEC 08-09, 2018
会议地点：
Hangzhou, PEOPLES R CHINA
会议主办单位：
[Chen, Deshan] Wuhan Univ Technol, Natl Engn Res Ctr Water Transport Safety, Intelligent Transportat Syst Res Ctr, Wuhan 430063, Hubei, Peoples R China.^[Teng, XuanXuan] Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan, Hubei, Peoples R China.
会议论文集名称：
International Symposium on Computational Intelligence and Design
关键词：
signal dependent noise;total generalized variation;variational method;image denoising;primal and dual hybrid gradient
摘要：
Rapid identification of plant disease is essential for food security. Deep learning, the latest breakthrough in computer vision, is promising for plant disease severity classification, as the method avoids the labor-intensive feature engineering and threshold-based segmentation. Using a public dataset of 54,306 images of diseased and healthy plant leaves collected under controlled conditions, a deep convolutional neural network and unsupervised methods are used to identify 14 crop species and 26 diseases. The trained model achieves an accuracy of 89.83% on a held-out test set, demonstrating the feasibility of this approach.
关键词：
Wireless sensor;Structural health monitoring;Capacitive strain sensor;AC Wheatstone bridge
摘要：
A capacitance based large-area electronics strain sensor, termed soft elastomeric capacitor (SEC) has shown various advantages in infrastructure sensing. The ability to cover large area enables to reflect mesoscale structural deformation, highly stretchable, easy to fabricate and low-cost feature allow full-scale field application for civil structure. As continuing efforts to realize full-scale civil infrastructure monitoring, in this study, new sensor board has been developed to implement the capacitive strain sensing capability into wireless sensor networks. The SEC has extremely low-level capacitance changes as responses to structural deformation; hence it requires high-gain and low-noise performance. For these requirements, AC (alternating current) based Wheatstone bridge circuit has been developed in combination a bridge balancer, two-step amplifiers, AM-demodulation, and series of filtering circuits to convert low-level capacitance changes to readable analog voltages. The new sensor board has been designed to work with the wireless platform that uses Illinois Structural Health Monitoring Project (ISHMP) wireless sensing software Toolsuite and allow 16bit low-noise data acquisition. The performances of new wireless capacitive strain sensor have been validated series of laboratory calibration tests. An example application for fatigue crack monitoring is also presented.
会议名称：
10th International Symposium on Multispectral Image Processing and Pattern Recognition (MIPPR) - Remote Sensing Image Processing, Geographic Information Systems, and Other Applications
摘要：
Now, Terahertz technology has been widely used in many fields, which is mainly related to imaging detection. While the frequency range of the terahertz-wave is located between microwave and visible light, whether the existing visible light principle is applicable to terahertz-wave should be studied again. Through experiment, we measure the terahertz-wave field amplitude distribution on the receiving plane perpendicular to the direction of propagation in the air and picture out the energy distribution curve; derive an energy decay formula of terahertz wave based on the results; design a terahertz wavelength apparatus using the F-P interferometer theory; test the wavelength between 1 and 3 THz from the SIFIR-50THz laser of American Corehent company; finally analyze the related factors affecting the measurement precision including the beam incident angle, mechanical vibration, temperature fluctuation and the refractive index fluctuation.
会议名称：
Annual Conference of the Chinese-Society-for-Optical-Engineering (CSOE) on Applied Optics and Photonics China (AOPC) - Optoelectronics and Micro/Nano-Optics
摘要：
In this paper, the novel method for free response signal of large-scale system is proposed. On the basis of random decrement method on the basic idea, two key parameters are discussed. One is the length of the system's output signal N, the other is the reference value of the amplitude A. in order to obtain more precise free response signal of system, using the result of eigenvalues analysis to modify the primary free response signal. Processing the measured acceleration from real system, this novel method can get approximate free response signal.
摘要：
Due to the constant temperature oven, the OCXO can have a higher frequency stability in both long-term and short-term comparing to other crystal oscillators. However, most of OCXOs are using passive temperature control components, such as heating resistors or power transistors, which makes OCXOs have long warm-up time and ease to be affected by the ambient temperature fluctuation. In this paper, demonstration of using the thermoelectric cooler as the temperature control for the OCXO has been studied. Simulation results show good consistence with the test results for using the TEC for the OCXO. Temperature control test results demonstrate the feasibility of using the TEC to control the temperature of the OCXO to improve the warm-up time and have better temperature stability.
期刊：
IOP Conference Series: Earth and Environmental Science,2017年61(1) ISSN：1755-1307
通讯作者：
Xie, Yan
作者机构：
[Xie, Yan] Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan 430048, Hubei, Peoples R China.;[Xiang, Tao] Wuhan Elect Power Supply Co State Grid, Wuhan 430015, Hubei, Peoples R China.;[Xiang, Tao] Wuhan Nari Ltd Liabil Co State Grid, Elect Power Res Inst, Wuhan 430074, Hubei, Peoples R China.
会议名称：
3rd International Conference on Energy Materials and Environment Engineering (ICEMEE)
会议时间：
MAR 10-12, 2017
会议地点：
Bangkok, THAILAND
会议主办单位：
[Xie, Yan] Wuhan Polytech Univ, Sch Elect & Elect Engn, Wuhan 430048, Hubei, Peoples R China.^[Xiang, Tao] Wuhan Elect Power Supply Co State Grid, Wuhan 430015, Hubei, Peoples R China.^[Xiang, Tao] Wuhan Nari Ltd Liabil Co State Grid, Elect Power Res Inst, Wuhan 430074, Hubei, Peoples R China.
会议论文集名称：
IOP Conference Series-Earth and Environmental Science
摘要：
In this paper, we study the resource allocation problem of two-cell cognitive radio systems, each cell includes multiple secondary users(SUs). The aim is to maximize the sum capacity of the two cells
摘要：
Compressed Sensing (CS) is an emerging theory which can sample the sparse signal or compressible signal via sub-Nyquist sampling rate and reconstruct the original signal with small amount of measurements. Since speech signal is sparse in Discrete Cosine Transform (DCT) domain, a kind of adaptive Bayesian Compressed Sensing (BCS) based on speech signal is proposed in this paper. In the one hand, our proposed method exploits the difference of energy within different speech frame to allot measurements adaptively for each speech frame aim to promote the quality of recovery speech signal. In the other hand, the position information of sparse coefficient in each speech frame is also utilized by our proposed method to recover its neighboring speech frame for reducing the recovery time of speech signal. The experimental results prove that our proposed method is surely effective and practical.
