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1. chinaXiv:201903.00101 [pdf]

Magnetic-Thermal Coupling Analysis of Air-Core Reactor in EAST Fast Control Power Supply

Hu Yunpeng; Bao Xiaohua; Zhang Cheng; Chen Yuanyang; Gao Ge
Subjects: Dynamic and Electric Engineering >> Electrical Engineering

当脉冲电流通过实验先进超导托卡马克 (EAST) 快控电源中空心电 抗器时会产生磁场,导致输出柜发热。为了解决热问题,在空心电抗器周围 安装一层或两层屏蔽体。电流幅值最大为 1 500A 时,求解空心电抗器周围磁 场分布以及输出柜的涡流损耗。将涡流损耗作为主要的热源,根据电磁学和 热力学理论建立电抗器的三维磁热耦合有限元模型。本文对空心电抗器的温 度场进行分析和讨论。结果表明,在屏蔽条件下空心电抗器的磁场和输出柜 的温度都会降低。

submitted time 2019-03-05 From cooperative journals:《电气工程学报》 Hits3512Downloads108 Comment 0

2. chinaXiv:201705.00259 [pdf]

Scattering effect of the high-index dielectric nanospheres for high performance hydrogenated amorphous silicon thin-film solar cells

Yang, ZH [Yang, Zhenhai][ 1 ]; Gao, PQ [Gao, Pingqi][ 1 ]; Zhang, C [Zhang, Cheng][ 2,3 ]; Li, XF [Li, Xiaofeng][ 2,3 ]; Ye, JC [Ye, Jichun][ 1 ]

Dielectric nanosphere arrays are considered as promising light-trapping designs with the capability of transforming the freely propagated sunlight into guided modes. This kinds of designs are especially beneficial to the ultrathin hydrogenated amorphous s

submitted time 2017-05-02 Hits175Downloads97 Comment 0

3. chinaXiv:201703.00308 [pdf]

Target brightness temperature simulation and analysis for the geostationary interferometric microwave sounder (GIMS)

Zhang, Ying; Liu, Hao; Wu, Ji; He, Jieying; Zhang, Cheng
Subjects: Geosciences >> Space Physics

Target brightness temperature maps can be used in geostationary interferometric microwave sounder (GIMS) system simulation. System simulation with accurate target brightness temperature maps can evaluate system performance in near real case and thus help adjust design parameters for the sensor before it is finally put into use. In this paper, method of simulating target brightness temperature using Weather Research and Forecasting Model and Radiative Transfer for TOVS (RTTOV) has been discussed. Target brightness temperature simulation results at oxygen absorption band and water-vapor absorption band have been presented. Some preliminary analyses of simulated brightness temperature for GIMS' observation have also been given.

submitted time 2017-03-10 Hits16176Downloads930 Comment 0

4. chinaXiv:201703.00298 [pdf]

A deblurring method for dynamic target observation of the geostationary interferometric microwave sounder (GIMS)

Zhang, Ying; Liu, Hao; Wu, Ji; Zhang, Cheng; He, Jieying
Subjects: Geosciences >> Space Physics

Brightness temperature change of observation target in one imaging period will introduce image blur to the retrieved image of geostationary interferometric microwave sounder (GIMS), which uses rotating circular array to realize time-sharing sampling other than snap-shot to reduce system complexity but meanwhile resulting in a relatively long imaging period. In this paper, an interpolation method utilizing time sequence of visibilities collected by time-sharing sampling is presented. The method is verified through a simulation system that simulates GIMS's observation process in viewing a series of near real case brightness temperature maps modeled by FNL/WRF/RTTOV method. Results show that the interpolation method can de-blur the image and reduce imaging error to the degree of snap-shot imaging. �2016 IEEE.

submitted time 2017-03-10 Hits1475Downloads515 Comment 0

5. chinaXiv:201703.00291 [pdf]

Analysis and simulation of GIMS observation on dynamic targets

Zhang, Ying; Liu, Hao; Wu, Ji; Zhang, Cheng; He, Jieying
Subjects: Geosciences >> Space Physics

Imaging period is an important consideration to geostationary interferometric microwave sounder (GIMS) when mapping fast changing target such as typhoon. GIMS simulation system with near real case observation target can evaluate system performance in different system configurations and thus help determine the optimal imaging period. In this paper, GIMS simulation system using MATLAB and near real case observation modeled by FNL/WRF/RTTOV method has been used to analyze the effect of imaging period on image quality. System simulation results for each frequency channel will be presented and analyses of imaging period's effect on image quality will also be given. �2016 IEEE.

submitted time 2017-03-10 Hits1399Downloads464 Comment 0

6. chinaXiv:201703.00288 [pdf]

Inter-element phase self-calibration for GIMS (geostationary interferometric microwave sounder)

Han, Donghao; Liu, Hao; Wu, Ji; Zhang, Cheng
Subjects: Geosciences >> Space Physics

The inter-element phase calibration plays an important role in the overall calibration scheme for synthetic aperture radiometer. The traditional relative phase calibration approach is to use correlated noise injection network, which will be difficult to be implemented in millimeter wave band due to the complexity of the waveguide divider network. A novel self-calibration method for interferometric radiometers with rotating thinned array, especially for the geostationary interferometric microwave sounder(GIMS), has been proposed in this paper. By using this approach, neither dedicated hardware nor dedicated calibration working model is needed to achieved the relative phase calibration. The self-calibration approach is inherently merged with the nominal observation working model of GIMS, thanks to the continuous array rotating of GIMS instrument. A running average scheme has been introduced into the self-calibration approach to enhance the SNR of the calibration data, which is normally very low with the natural earth scene. The method is demonstrated by both simulation and field imaging experiment. �2016 IEEE.

submitted time 2017-03-10 Hits859Downloads494 Comment 0

7. chinaXiv:201605.01055 [pdf]

Massive 2-form field and holographic ferromagnetic phase transition

Cai, Rong-Gen; Yang, Run-Qiu; Wu, Ya-Bo; Zhang, Cheng-Yuan
Subjects: Physics >> The Physics of Elementary Particles and Fields

In this paper we investigate in some detail the holographic ferromagnetic phase transition in an AdS(4) black brane background by introducing a massive 2-form field coupled to the Maxwell field strength in the bulk. In two probe limits, one is to neglect the back reaction of the 2-form field to the background geometry and to the Maxwell field, and the other to neglect the back reaction of both the Maxwell field and the 2-form field, we find that the spontaneous magnetization and the ferromagnetic phase transition always happen when the temperature gets low enough with similar critical behavior. We calculate the DC resistivity in a semi-analytical method in the second probe limit and find it behaves as the colossal magnetic resistance effect in some materials. In the case with the first probe limit, we obtain the off-shell free energy of the holographic model near the critical temperature and compare with the Ising-like model. We also study the back reaction effect and find that the phase transition is always second order. In addition, we find an analytical Reissner-Norstrom-like black brane solution in the Einstein-Maxwell-2-form field theory with a negative cosmological constant.

submitted time 2016-05-08 Hits569Downloads272 Comment 0

8. chinaXiv:201605.00283 [pdf]

TARGET BRIGHTNESS TEMPERATURE SIMULATION AND ANALYSIS FOR THE GEOSTATIONARY INTERFEROMETRIC MICROWAVE SOUNDER (GIMS)

Zhang, Ying; Liu, Hao; Wu, Ji; He, Jieying; Zhang, Cheng
Subjects: Geosciences >> Space Physics

Target brightness temperature maps can be used in geostationary interferometric microwave sounder (GIMS) system simulation. System simulation with accurate target brightness temperature maps can evaluate system performance in near real case and thus help adjust design parameters for the sensor before it is finally put into use. In this paper, method of simulating target brightness temperature using Weather Research and Forecasting Model and Radiative Transfer for TOVS (RTTOV) has been discussed. Target brightness temperature simulation results at oxygen absorption band and water-vapor absorption band have been presented. Some preliminary analyses of simulated brightness temperature for GIMS' observation have also been given.

submitted time 2016-05-03 Hits737Downloads451 Comment 0

9. chinaXiv:201605.00282 [pdf]

IMAGING SIMULATION OF THE MICROWAVE RADIOMETER ABOARD THE MICAP FOR SEA SURFACE SALINITY MEASUREMENT

Zhang, Cheng; Liu, Hao; Wu, Lin; Wu, Ji
Subjects: Geosciences >> Space Physics

Sea surface salinity as an ocean variable plays an important role in various components of the water and energy cycle. Recently a Chinese space mission using a new concept of Microwave Imager Combined Active and Passive (MICAP) at L-band is proposed for the ocean salinity measurement. MICAP uses interferometric techniques for both the radiometer and the scatterometer, which adopt two kinds of linear array feeds sharing one 3x4.5 m parabolic cylinder reflector. This paper is focused on the microwave interferometric radiometer (MIR) aboard the MICAP, and discusses the imaging simulation, imaging algorithm, and instrument performance.

submitted time 2016-05-03 Hits772Downloads456 Comment 0

10. chinaXiv:201605.00280 [pdf]

MICAP (MICROWAVE IMAGER COMBINED ACTIVE AND PASSIVE): A NEW INSTRUMENT FOR CHINESE OCEAN SALINITY SATELLITE

Liu, Hao; Zhu, Di; Niu, Lijie; Wu, Lin; Wang, Caiyun; Chen, Xue; Zhao, Xin; Zhang, Cheng; Zhang, Xiangkun; Yin, Xiaobin; Wu, Ji
Subjects: Geosciences >> Space Physics

Sea surface salinity (SSS) plays an important role in global water cycle. In recent years, satellite based remote sensing has proven to be a promising approach for global SSS observation. A new payload concept, named MICAP (microwave imager combined active and passive), has been introduced in this paper. MICAP is a suit of active/passive instrument package, which includes L/C/K band one-dimensional MIR (microwave interferometric radiometer) and L-band DBF (digital beamforming) scatterometer, sharing a parabolic cylinder reflector. MICAP has been selected to be a candidate payload for future Chinese ocean salinity mission. In this paper, the MICAP instrument concept, specification and preliminary system design will be introduced.

submitted time 2016-05-03 Hits596Downloads409 Comment 0

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