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Search Results: 1 - 10 of 46032 matches for " KANG Wen-Qin "
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Virtual Antenna Array Analysis for MIMO Synthetic Aperture Radars
Wen-Qin Wang
International Journal of Antennas and Propagation , 2012, DOI: 10.1155/2012/587276
Abstract: Multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) that employs multiple antennas to transmit orthogonal waveforms and multiple antennas to receive radar echoes is a recently proposed remote sensing concept. It has been shown that MIMO SAR can be used to improve remote sensing system performance. Most of the MIMO SAR research so far focused on signal/data models and corresponding signal processing algorithm. Little work related to MIMO SAR antenna analysis can be found. One of the main advantages of MIMO SAR is that the degrees of freedom can be greatly increased by the concept of virtual antenna array. In this paper, we analyze the virtual antenna array for MIMO SAR high-resolution wide-swath remote sensing applications. The one-dimensional uniform and nonuniform linear antenna arrays are investigated and their application potentials in high-resolution wide-swath remote sensing are introduced. The impacts of nonuniform spatial sampling in the virtual antenna array are analyzed, along with a multichannel filtering-based reconstruction algorithm. Conceptual system and discussions are provided. It is shown that high operation flexibility and reconfigurability can be obtained by utilizing the virtual antenna arrays provided by the MIMO SAR systems, thus enabling a satisfactory remote sensing performance.
A Flexible Phased-MIMO Array Antenna with Transmit Beamforming
Wen-Qin Wang,Huaizong Shao
International Journal of Antennas and Propagation , 2012, DOI: 10.1155/2012/609598
Abstract: Although phased-array antennas have been widely employed in modern radars, the requirements of many emerging applications call for new more advanced array antennas. This paper proposes a flexible phased-array multiple-input multiple-output (MIMO) array antenna with transmit beamforming. This approach divides the transmit antenna array into multiple subarrays that are allowed to overlap each subarray coherently transmits a distinct waveform, which is orthogonal to the waveforms transmitted by other subarrays, at a distinct transmit frequency. That is, a small frequency increment is employed in each subarray. Each subarray forms a directional beam and all beams may be steered to different directions. The subarrays jointly offer flexible operating modes such as MIMO array which offers spatial diversity gain, phased-array which offers coherent directional gain and frequency diverse array which provides range-dependent beampattern. The system performance is examined by analyzing the transmit-receive beampatterns. The proposed approach is validated by extensive numerical simulation results.
Azimuth-Variant Signal Processing in High-Altitude Platform Passive SAR with Spaceborne/Airborne Transmitter
Wen-Qin Wang,Huaizong Shao
Remote Sensing , 2013, DOI: 10.3390/rs5031292
Abstract: High-altitude platforms (HAP) or near-space vehicle offers several advantages over current low earth orbit (LEO) satellite and airplane, because HAP is not constrained by orbital mechanics and fuel consumption. These advantages provide potential for some specific remote sensing applications that require persistent monitoring or fast-revisiting frequency. This paper investigates the azimuth-variant signal processing in HAP-borne bistatic synthetic aperture radar (BiSAR) with spaceborne or airborne transmitter for high-resolution remote sensing. The system configuration, azimuth-variant Doppler characteristics and two-dimensional echo spectrum are analyzed. Conceptual system simulation results are also provided. Since the azimuth-variant BiSAR geometry brings a challenge for developing high precision data processing algorithms, we propose an image formation algorithm using equivalent velocity and nonlinear chirp scaling (NCS) to address the azimuth-variant signal processing problem. The proposed algorithm is verified by numerical simulation results.
Radar-to-Radar Interference Suppression for Distributed Radar Sensor Networks
Wen-Qin Wang,Huaizong Shao
Remote Sensing , 2014, DOI: 10.3390/rs6010740
Abstract: Radar sensor networks, including bi- and multi-static radars, provide several operational advantages, like reduced vulnerability, good system flexibility and an increased radar cross-section. However, radar-to-radar interference suppression is a major problem in distributed radar sensor networks. In this paper, we present a cross-matched filtering-based radar-to-radar interference suppression algorithm. This algorithm first uses an iterative filtering algorithm to suppress the radar-to-radar interferences and, then, separately matched filtering for each radar. Besides the detailed algorithm derivation, extensive numerical simulation examples are performed with the down-chirp and up-chirp waveforms, partially overlapped or inverse chirp rate linearly frequency modulation (LFM) waveforms and orthogonal frequency division multiplexing (ODFM) chirp diverse waveforms. The effectiveness of the algorithm is verified by the simulation results.
Water and fertilizer use efficiency of potato under different irrigation patterns in North Yin Mountain Region
阴山北麓马铃薯在不同灌溉模式下的水肥效率

QIN Yong-Lin,JING Tao,KANG Wen-Qin,TIAN Yan-Fang,FAN Ming-Shou,
秦永林
,井 涛,康文钦,田艳芳,樊明寿

中国生态农业学报 , 2013,
Abstract: The North Yin Mountain Region (NYMR), the main potato production region in Inner Mongolia, is highly limited in water resources. Water-saving cultivation techniques have therefore been increasingly used in this region in recent years. To evaluate the effects of different irrigation methods on water and nutrient use efficiency and the eco-environmental benefits of potato cultivation, field experiments were conducted in 2009-2010 in the Wuchuan Region of NYMR, Inner Mongolia. The field experiment was consisted of four different irrigation patterns - flood irrigation (FI), ground sprinkler (GS), drip irrigation (DI) and under-mulch-drip irrigation (UMDI). The irrigation patterns were compared in terms of potato tuber yield, water and nutrient use efficiency, net economic income and soil inorganic nitrogen residue. The results showed that UMDI increased potato yield over conventional farm practice FI, GS and DI by 35.7%, 26.0% and 12.9%, water use efficiency by 200.2%, 91.8% and 23.7% and net economic income by 37.7%, 30.1% and 10.7%, respectively. Nitrogen fertilizer partial factor productivity under UMDI was respectively 50.6 kg·kg-1, 39.8 kg·kg-1 and 22.0 kg·kg-1 higher than those under FI, GS and DI. Also phosphorus fertilizer partial factor productivity under UMDI was respectively 126.6 kg·kg-1, 99.4 kg·kg-1 and 55.0 kg·kg-1 higher than those under FI, GS and DI. Then potassium fertilizer partial factor productivity under UMDI was respectively 42.3 kg·kg-1, 33.2 kg·kg-1 and 18.4 kg·kg-1 higher than those under FI, GS and DI. Soil inorganic nitrogen residue in the 60~120 cm soil layer after potato harvest was 102.95 kg·hm-2 under FI, which was 0.36, 1.11 and 1.28 times higher than those under GS, DI and UMDI, respectively. The above results suggested that DI and UMDI not only saved water resources, but also enhanced potato yield, nutrient use efficiency and net economic income in the research area. This was critical for reducing the risk of environmental pollution due to nitrogen leaching. It was therefore important to intensify DI and UMDI irrigation patterns in potato fields in the NYMR for higher yields, resources use efficiencies and low environmental pollution risks.
THE EFFECT OF DOPING CONCENTRATION ON BAND-GAP NARROWING OF p-TYPE GaAs
掺杂浓度对p-GaAs的带隙变窄的影响

CHENG WEN-QIN,MEI XIAO-BING,LIU SHUANC,LIU YU-LONG,LI YONG-KANG,ZHOU JUN-MING,
程文芹
,梅笑冰,刘双,刘玉龙,李永康,周均铭

物理学报 , 1992,
Abstract: The band-gap narrowing of p-type GaAs as a function of doping concentrafion has been investigated by photoluminescence spectroscopy on samples grown by molecular beam epitaxy on (110) semi-insulating GaAs. It was first found that the band-gap narrowing of p-type GaAs comes from the moving up of valence band, the location of dopant level (band) remains unchanged relative to conduction band, and the ionization energy decreases with the increase of doping concentration.
Range-Angle-Dependent Beamforming by Frequency Diverse Array Antenna
Wen-Qin Wang,Huaizong Shao,Jingye Cai
International Journal of Antennas and Propagation , 2012, DOI: 10.1155/2012/760489
Abstract: This paper proposes a range-angle-dependent beamforming for frequency diverse array (FDA) antenna systems. Unlike conventional phased-array antenna, the FDA antenna employs a small amount of frequency increment compared to the carrier frequency across the array elements. The use of frequency increment generates an antenna pattern that is a function of range, time and angle. The range-angle-dependent beamforming allows the FDA antenna to transmit energy over a desired range or angle. This provides a potential to suppress range-dependent clutter and interference which is not accessible for conventional phased-array systems. In this paper, a FDA radar signal model is formed and the range-angle-dependent beamforming performance is examined by analyzing the transmit/receive beampatterns and the output signal-to-interference-plus-noise ratio (SINR) performance. Extensive simulation examples and results are provided.
Near-Space Microwave Radar Remote Sensing: Potentials and Challenge Analysis
Wen-Qin Wang,Jingye Cai,Qicong Peng
Remote Sensing , 2010, DOI: 10.3390/rs2030717
Abstract: Near-space, defined as the region between 20 km and 100 km, offers many new capabilities that are not accessible to low earth orbit (LEO) satellites and airplanes, because it is above storm and not constrained by either the orbital mechanics of satellites or the high fuel consumption of airplanes. By placing radar transmitter/receiver in near-space platforms, many functions that are currently performed with satellites or airplanes could be performed in a cheaper way. Inspired by these advantages, this paper introduces several near-space vehicle-based radar configurations, such as near-space passive bistatic radar and high-resolution wide-swath (HRWS) synthetic aperture radar (SAR). Their potential applications, technical challenges and possible solutions are investigated. It is shown that near-space is a satisfactory solution to some specific remote sensing applications. Firstly, near-space passive bistatic radar using opportunistic illuminators offers a solution to persistent regional remote sensing, which is particularly interest for protecting homeland security or monitoring regional environment. Secondly, near-space provides an optimal solution to relative HRWS SAR imaging. Moreover, as motion compensation is a common technical challenge for the described radars, an active transponder-based motion compensation is also described.
GROWTH AND TRANSPORT PROPERTIER OF MODULATION DOPED GaAs/AlGaAs HETEROSTRUCTURES
调制掺杂GaAs/N-AlGaAs异质结的制备及输运性质

ZHOU JUN-MING,HUANG YI,MENG QING-HUI,CHENG WEN-QIN,WU YONG-SHENG,LI YONG-KANG,YANG ZHONG-XING,
周均铭
,黄绮,孟庆惠,程文芹,吴永生,李永康,杨中兴

物理学报 , 1986,
Abstract: The high quality modulation doped GaAs/N-AlGaAs heterostructures have been grown by a vertical molecular beam epitaxy system (MBE). Electron mobility of two dimentional electron gas (2DBG) at 4.2 K has reached as high as 4.26×105cm2/V·s (in the dark) and 5.9×105cm2/V·s (under light illumination). The polaron mass of 2DEG was determined by analysis of oscillatory resistance change of magnetophonon resonance in pulsed magnetic field. The mobility enhancement of 2DEG in low field and quantum Hall effect in high field at 4.2 K were also studied.
Identification of PCR Markers Associtated with Cytoplasmic Male Sterility in Brassica oleracea var. Botrytis
花椰菜细胞质雄性不育基因特异PCR标记的筛选Identification of PCR markers associtated with cytoplasmic male sterility in Brassica oleracea var botrytis

WANG Chun-Guo,SONG Wen-Qin,
王春国
,宋文芹WANG Chun-Guo,SONG Wen-Qin

遗传 , 2005,
Abstract: The homology-based candidate gene method was used to identify the specific PCR markers linked to cytoplasmic male sterility (CMS) in cauliflower(Brassica oleracea var. Botrytis.). By searching the DNA and protein (data-)base of NCBI , correlative genes or open reading frames were identified . Through analysis of biosoft, based on the conservative regions ,five primers were designed . Among them, only primer P9/P10 produced a 313- bp specific fragment. Identified by individual plant testing , analysis of RT-PCR and dot blot ,this fragment was only found in CMS cauliflower knxd612.Analysis of the sequence indicated it was high homologous(98%) with orf138 of Ogura CMS radish. Preliminary results suggested that the cytoplasmic type of CMS cauliflower knxd612 might belong to Ogura type. This research offered a good foundation to further investigate the CMS mechanism of cauliflower at molecular (level.)
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