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A Concentric Array for Generating Multimode OAM Waves

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Journal of Communications and information Networks 2022年第3期7卷 333-348页

作者： Yanni Wang Xuehong Sun Liping Liu School of Physics and Electronic-Electrical Engineering Ningxia UniversityYinchuan 750021China ningxia key laboratory of intelligent sensing of desert information Ningxia UniversityYinchuan 750021China

For the problem of multiplexing multimodal vortex electromagnetic waves,a double-ring concentric uniform circular array(CUCA)consisting of 12 circularly polarized antennas(4 inner rings and 8 outer rings)is proposed in this paper.A complex feeding network is solved by rotating the circularly polarized antennas at a certain *** antennas are rotationally symmetric and point to the center,generating orbital angular momentum(OAM)waves by feeding the same amplitude and phase *** addition,this paper combines millimeter wave(mm-wave)and ultra-wideband(UWB)with *** proposed antenna array can generate OAM beams at 30∼40 GHz with l=−1,−*** l=−1 the relative bandwidth is 25.2% and the gain is 8.03 dBi;when l=−2 the relative bandwidth is 27.7% and the gain is 9.43 *** analysis of simulation results shows that the antenna array has UWB performance,good gain,and a standard spiral phase distribution,which can provide some practical significance for modal multiplexing of mm-wave band OAM.

关键词： orbital angular momentum(OAM) concentric uniform circular array(CUCA) millimeter wave(mm-wave) ultra-wideband(UWB) modal multiplexing

Electrostatic force of dust deposition originating from contact between particles and photovoltaic glass

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Chinese Physics B 2021年第10期30卷 267-273页

作者： Xing-Cai Li Juan Wang Guo-Qing Su School of Physics and Electronic-Electrical Engineering Ningxia UniversityYinchuan 750021China ningxia key laboratory of intelligent sensing&desert information Ningxia UniversityYinchuan 750021China Xinhua College of ningxia University Yinchuan 750021China

Charged photovoltaic glass produces an electrostatic *** electrostatic field exerts an electrostatic force on dust particles,thus making more dust particles deposited on the *** this paper,the contact electrification between the deposited dust particles and the photovoltaic glass is ***,the surface charge density model of the photovoltaic glass and the electrostatic force of charged particles are *** results show that with the increasing of the particle impact speed and the inclination angle of the photovoltaic panel,the charges on particles increase to different *** a given condition,the electrostatic forces acting on the charged particles at different positions above the glass plate form a bell-shaped distribution at a macro level,and present a maximum value in the center of the *** the distance between the particle and the charged glass decreases,the electrostatic force exerted on the particle increases significantly and fluctuates ***,its mean value is still higher than the force caused by gravity and the adhesion force,reported by some ***,we suggest that photovoltaic glass panels used in the severe wind-sand environment should be made of an anti-static transparent material,which can lessen the dust particles accumulated on the panels.

关键词： particle electrification electrostatic force photovoltaic glass dust deposition

Electromagnetic scattering of charged particles in a strong wind-blown sand electric field

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Chinese Physics B 2019年第3期28卷 218-222页

作者： Xingcai Li Xuan Gao Juan Wang School of Physics and Electronic-Electrical Engineering Ningxia UniversityYinchuan 750021China ningxia key laboratory of intelligent sensing for the desert information Ningxia UniversityYinchuan 750021China Xinhua College Ningxia UniversityYinchuan 750021China

Some field experimental results have shown that the moving sands or dust aerosols in nature are usually electrified,and those charged particles also produce a strong electric field in air, which is named as wind-blown sand electric *** scholars have pointed out that the net charge on the particle significantly enhances its electromagnetic(EM) extinction properties, but up to now, there is no conclusive research on the effect of the environmental electric field. Based on the extended Mie theory, the effect of the electric field in a sandstorm on the EM attenuation properties of the charged larger dust particle is studied. The numerical results indicate that the environmental electric field also has a great influence on the particle's optical properties, and the stronger the electric field, the bigger the effect. In addition, the charged angle, the charge density, and the particle radius all have a specific impact on the charged particle's optical properties.

关键词： wind-blown sand electric field extended Mie theory charged particle scattering

Effect of photovoltaic panel electric field on the wind speed required for dust removal from the panels

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Chinese Physics B 2023年第8期32卷 296-303页

作者：李兴财王娟刘滢格马鑫 ningxia key laboratory of desert information&intelligent sensing School of PhysicsElectronic and Electrical EngineeringNingxia UniversityYinchuan 750021China key laboratory of Mechanics on Disaster and Environment in Western China the Ministry of EducationLanzhou UniversityLanzhou 730000China Xinhua College of ningxia University Yinchuan 750021China

Methods to remove dust deposits by high-speed airflow have significant potential applications,with optimal design of flow velocity being the core *** this paper,we discuss the wind speed required for particle removal from photovoltaic(PV)panels by compressed air by analyzing the force exerted on the dust deposited on inclined photovoltaic panels,which also included different electrification mechanisms of dust while it is in contact with the PV *** results show that the effect of the particle charging mechanism in the electric field generated by the PV panel is greatly smaller than the effect of the Van der Waals force and gravity,but the effect of the particle charged by the contact electrification mechanism in the electrostatic field is very *** wind speed required for dust removal from the PV panel increases linearly with the PV panel electric field,so we suggest that the nighttime,when the PV electric field is relatively small,would be more appropriate time for dust *** above results are of great scientific importance for accurately grasping the dust distribution law and for achieving scientific removal of dust on PV panels.

关键词： photovoltaic power generation dust removal electrostatic force required wind speed contact electrification

A 3-D Polarization Quadrature Amplitude Modulation Method and Constellation Mapping

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China Communications 2015年第10期12卷 16-26页

作者： SUN Xuehong ZHANG Haiying ZENG Zhimin GUO Caili Beijing key laboratory of Network System Architecture and Convergence School of Information and Communication EngineeringBeijing University of Posts and Telecommunications key laboratory of intelligent sensing for desert information School of Physics Electrical EngineeringNingxia University

As a new three-dimensional(3-D)modulation,Polarization Quadrature Amplitude Modulation(PQAM) can be regarded as the combination of Pulse amplitude modulation(PAM) and Quadrature Amplitude Modulation(QAM) *** can better improve the digital communication efficiency and reduce the Symbol error rate(SER) of the system than one-dimensional or two-dimensional modulation *** to design a feasible constellation is the most concerned problem of PQAM *** paper first studies the relationship between the SER theoretical value of PQAM and the distribution of M and N,proposes a new M,N allocation ***,a new and straightforward design method of constructing higher-level 3-D signal constellations,which can be matched with the PQAM,and the constellation can divided into three different structures according to the ary for ***,the simulation results show that:in PQAM system,the modulation scheme and the constellation mapping scheme are proposed in this paper which can effectively reduce the system SER and improve the anti-noise performance of the system.

关键词： polarization quadrature amplitude modulation minimum euclidean distance symbol error probability 3-D constellation

Detecting sand-dust storms using a wind-profiling radar

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Journal of Arid Land 2017年第5期9卷 753-762页

作者： WANG Minzhong MING Hu HUO Wen XU Hongxiong LI Jiangang LI Xingcai Institute of desert Meteorology China Meteorological Administration Northwest Air Traffic Management Bureau Civil Aviation Administration of China State key laboratory of Severe Weather Chinese Academy of Meteorological Science School of Physics & Electrical information Engineering Ningxia Key Laboratory of Intelligent Sensing for the Desert Information Ningxia University

Sand-dust storm is a type of disastrous weather, typically occurring in arid and semi-arid climates. This study selected a region in the hinterlands of the Taklimakan desert, called the Tazhong region, as the experimental area to quantitatively estimate the particle concentrations of sand-dust storms using the boundary layer wind-profiling radar. We thoroughly studied the radar echo signals and reflectivity factor features during the sand-dust storms. The results indicate that（1） under sand-dust storm conditions, boundary layer wind-profiling radar cannot capture the complete information regarding horizontal wind velocity and direction, but it can obtain the backscattering intensity of sand-dust storms; and（2） during sand-dust storms particle size distributions in the surface layer closely resemble log-normal distributions, with sand-dust particles sizes of 90–100 μm accounting for the maximum particle probability. Retrieved particle size distributions at heights of 600, 800, and 1000 m follow log-normal distributions, and the expected value of particle diameter decreases gradually with increasing height. From the perspective of orders of magnitude, the retrieved results for particle number concentrations and mass concentrations are consistent with previous aircraft-detected results, indicating that it is basically feasible to use boundary layer wind-profiling radar to quantitatively detect the particle concentrations of dust storms.

关键词： echo signal mass concentration retrieval method sand-dust storm wind-profiling radar Taklimakan desert

Experimental research on the convective heat transfer coefficient of photovoltaic panel

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Experimental research on the convective heat transfer coeffi...

Downlink energy efficiency modeling and optimization with backhaul awareness and interference price in ultra cellular HetNet

中国力学大会-2021+1

作者： Weiwei Hu Xingcai Li Juan Wang Zihang Tian Bin Zhou Jinpeng Wu Runmin Li Wencang Li Ning Ma Jixuan Kang Yong Wang Jialong Tian Jibin Dai School of Physics and Electronic-Electrical Engineering Ningxia University ningxia key laboratory of intelligent sensing& desert information Ningxia University Xinhua College of ningxia University

The convective heat transfer between wind and photovoltaic(PV) panels will cause fluctuations in the temperature and performance of PV cells, which have a great negative impact on the grid-connected solar energy. The development of large-scale PV power plants in desertification areas has certain advantages, but the output power fluctuations caused by windy-dusty environment will be more common and important. This paper established a new model of convective heat transfer coefficient with and without dust deposition. Results show that the convective heat transfer coefficient of PV panel is not only affected by wind speed and dust density, but also related to the tilt angle of panel. As the dust accumulation density increases, the convective heat transfer coefficient of the dusty PV panel firstly increasing and then decreasing, and the maximum value appears when the dust deposition density is20 g/m. In addition, the average heat transfer coefficient of dusty PV module is slightly higher than that of clean PV panels by 4.13%, which can be revealed by the thermal diffusivity. This work confirms the influence of dust on the convective heat transfer characteristics, and provides an important basis for establishing a more practical PV panel temperature prediction model.? 2021 Elsevier Ltd. All rights reserved.

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The Journal of China Universities of Posts and Telecommunications 2019年第2期26卷 67-81页

作者： Li Bo Sun Xuehong Li Chunshu Xue Kaiping Zhang Xiaoguang ningxia key laboratory of intelligent sensing for desert information Ningxia UniversityYinchuan 750021China Department of Electronic Engineering and information Science University of Science and Technology of ChinaHefei 230026China Academy of Opto-Electronics Chinese Academy of SciencesBeijing 100080China

The cellular heterogeneous network(HetNet) with ultra dense small cells is called ultra cellular *** energy efficiency for this network is very important for future green wireless *** data rates and power consumptions for three parts(i.e.,macro cells,small cells,and mixed backhaul links) in ultra cellular HetNet are jointly formulated to model downlink energy efficiency considering the active base stations(BSs) and inactive ***,in order to decrease the downlink co-channel interference,the interference price functions are also jointly set up for the three parts in ultra cellular ***,energy efficiency optimization iterative algorithm scheme using the fractional programming and Lagrangian multiplier with constraints for density of ultra dense small cells and fraction of mixed backhaul links is presented with interference *** convergence and computation complexity are also proved in this *** numerical simulations finally demonstrate convergence behavior of the proposed *** comparison,some conclusion can be *** energy efficiency of system is lower as the density of small cell is *** effect on maximizing energy efficiency with interference price outperforms that without interference *** the energy efficiency increases as the fraction of mixed backhaul links is higher because of more power consumption in the microwave backhaul links.

关键词： ultra cellular energy efficiency optimization backhaul link interference price

A Study on The Multi-Antenna Geometrical Depolarization Channel Modeling

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China Communications 2016年第3期13卷 105-114页

作者： SUN Xuehong YANG Xiaoli ZENG Zhimin ZHANG Cheng BAI Bing Beijing key laboratory of Network System Architecture and Convergence School of Information and Communication EngineeringBeijing University of Posts and TelecommunicationsBeijing 100876China key laboratory of intelligent sensing for desert information School of Physics Electrical EngineeringNingxia UniversityYinchuan750021China

The traditional geometrical depolarization model that single transmitter to single receiver provides a simple method of polarization channel modeling. It can obtain the geometrical depolarization effect of each path if known the antenna configuration, the polarization field radiation pattern and the spatial distribution of scatters. With the development of communication technology, information transmission spectrum is more and more scarce. The original model provides only a single channel polarization state, so the information will be limited that the polarization state carries in the polarization modulation. The research is so significance that how to carries polarization modulation information by using multi-antenna polarization state. However, the present study shows that have no depolarization effect model for multi-antenna systems. In this paper, we propose a multi-antenna geometrical depolarization model. On the basis of a single antenna to calculate the depolarization effect of the model, and through simulation to analysis the main factors that influence the depolarization effect. This article provides a multi-antenna geometrical depolarization channel modeling that can applied to large-scale array antenna, and to some extent increase the speed of information transmission.

关键词： large-scale array antenna multi-antenna channel modeling depolarization effect cross polarization discrimination