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Mie series for electromagnetic scattering of chiral metamaterials sphere

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Journal of Systems Engineering and Electronics 2011年第6期22卷 885-891页

作者： maoyan wang Chengwei Qiu Jun Xu Yuliang Dong Hu Zheng Hailong Li School of Physical Electronics University of Electronic Science and Technology of China Chengdu 610054 P. R. China Department of Electrical and Computer Engineering National University of Singapore Singapore 119620 Singapore

The electromagnetic scattering of chiral metamaterials is simulated with the Mie series *** on the spherical harmonics vector function in chiral metamaterials,the electromagnetic fields inside and outside of chiral metamaterials sphere are *** applying the continuous boundary condition between the chiral metamaterials and surrounding medium,and the transformation from linearly to circularly polarized electric field components,the co-polarized and cross-polarized bistatic radar cross scattering（RCS） of chiral metamaterials sphere are *** to overcome the instability of chiral metamaterials sphere of Mie series formula is *** electromagnetic scattering of chiral metamaterials,normal media and metamaterials are *** numerical results show that the existence of chirality ξ of chiral metamaterials can decrease the bistatic RCS compared with the same size as normal media sphere.

关键词： chiral metamaterials Mie series radar cross scattering(RCS) chirality.

Exploring the occurrence rate of PMSE-Es by Digisonde at Tromsø

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Earth and Planetary Physics 2021年第2期5卷 187-195页

作者： HaiLong Li ShuCan Ge Lin Meng maoyan wang Abdur Rauf Safi Ullah School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China National Key Laboratory of Electromagnetic Environment China Research Institute of Radiowave PropagationQingdao 266107China School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China

Polar mesosphere summer echoes(PMSE)are observed simultaneously with Digisonde and EISCAT VHF *** phenomenon of irregular Es layers is called PMSE-like or PMSE-Es(Polar Mesosphere Summer Echoes-Es)and has some relationship with real *** this paper,the characteristics of irregular Es layers at 80–100 km were observed by Digisonde at Tromsøduring 2003–2014 are statistically analyzed with *** diurnal,day-to-day and year-to-year variations and discrepancies of occurrence rate between PMSE and PMSE-Es are compared with the statistical results observed by Esrange MST radar(ESRAD),and the reasons are *** results show that the trends in the occurrence rate of PMSE-Es are similar to the trends in the occurrence rate of PMSE,but there are some notable *** occurrence rate of PMSE-Es is much lower than the occurrence rate of *** minimum value of PMSE-Es appears 1–2 hours earlier than the minimum value of the PMSE occurrence rate,while PMSE-Es appear earlier than PMSE in the *** addition,there is a significant positive correlation between the annual average occurrence rates of PMSE and *** is a relatively important occurrence in the polar *** of its characteristics can provide new ideas and methods for studying the formation mechanism of PMSE.

关键词： Polar mesosphere summer echoes Digisonde EISCAT VHF radar PMSE-Es Esrange MST radar

Effect of ions on conductivity and permittivity in the Polar Mesosphere Summer Echoes region

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Earth and Planetary Physics 2021年第2期5卷 196-204页

作者： Safi Ullah HaiLong Li Abdur Rauf Lin Meng Bin wang ShuCan Ge maoyan wang School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China Terahertz Science and Technology Key Laboratory of Sichuan Province Chengdu 610054China National Key Laboratory of Electromagnetic Environment China Research Institute of Radiowave PropagationQingdao 266107China School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China

For the first time,the effect of ions on complex conductivity and permittivity of dusty plasma at Polar Mesosphere Summer Echoes(PMSE)altitude is *** of ions higher mass and smaller thermal velocity,generally,their effects are not considered in the study of electromagnetic properties of dusty *** this study,we modified the equations of conductivity and permittivity by adding the effect of *** the PMSE altitude region between 80 and 90 km,a local reduction in electron density(i.e.,an electron biteout),is produced by electron absorption onto dust *** bite-out condition contains high dust density and smaller electron *** simulation results in comparatively strong bite-out conditions,we found that the ion effects on conductivity become significant with smaller dust size,lower electron temperature,and lower neutral *** comparatively weak bite-out conditions,the ion effects on conductivity become significant with larger dust size,higher electron temperature,and higher neutral *** the other hand,for different dust sizes,electron temperatures and neutral density,the ion effects on complex permittivity become significant only in very strong bite-out *** on these simulation results,we conclude that,in the absence of electron bite-out conditions,the effect of ions on complex conductivity and permittivity is not significant and can be ***,during bite-out conditions,the effect of ions becomes significant and cannot be ignored because it significantly changes the conductivity and permittivity of dusty plasmas.

关键词： PMSE electromagnetic waves collision and charging effect conductivity and permittivity

PMSE dependence on frequency observed simultaneously with VHF and UHF radars in the presence of precipitation

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Plasma Science and Technology 2018年第11期20卷 61-69页

作者： Safi ULLAH Hailong LI Abdur RAUF Lin MENG Bin wang maoyan wang School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054People＇s Republic of China

Using PMSE （polar mesosphere summer echoes） observations in combination with particle flux measurements obtained with detectors onboard the Geostationary Operational Environmental Satellite （GOES） a special condition is shown for the occurrence of rare observed UHF PMSE. When electron flux observed from GOES satellites show a decrease, then after being in the presence of precipitation UHF PMSE occurs. The heating effect on PMSE is small when the UHF electron density is enhanced at 90 km due to particle precipitation. We analyzed and compared the frequency dependence of PMSE under the condition of high energy particle precipitation in July of 2004 and 2007 at well separated frequencies （224 and 930 MHz） at the same site, height, and time. The frequency index varies with height and time. At different heights, the maximum as well as the minimum value of volume reflectivity at VHF is greater than that at UHF with 2 to 3 orders of magnitude. A new qualitative method for the analysis of dust distribution is used by analyzing the relationship between volume reflectivity and frequency index. In agreement with the results of the model it is shown that dust particles of smaller size generally did not occur at the edges, instead they occurred in the middle PMSE regions.

关键词： polar mesosphere summer echoes (PMSE) volume reflectivity ionospheric disturbances

On the radar frequency dependence of polar mesosphere summer echoes

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Earth and Planetary Physics 2020年第6期4卷 571-578页

作者： ShuCan Ge HaiLong Li Lin Meng maoyan wang Tong Xu Safi Ullah Abdur Rauf Abdel Hannachid School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China National Key Laboratory of Electromagnetic Environment China Research Institute of Radio Wave PropagationQingdao 266107China Department of Meteorology Stockholm UniversitySE-106-91StockholmSweden

Polar mesosphere summer echoes(PMSEs)are very strong radar echoes in the polar mesopause in local *** we present the frequency dependence of the volume reflectivity and the effect of energetic particle precipitation on modulated PMSEs by using PMSEs observations carried out by European Incoherent SCATter(EISCAT)heating equipment simultaneously with very high frequency(VHF)radar and ultra high frequency(UHF)radar on 12 July *** to the experimental observations,the PMSEs occurrence rate at VHF was much higher than that at UHF,and the altitude of the PMSEs maximum observed at VHF was higher than that at *** regions were observed by VHF radar between high energetic particle precipitation and the *** addition,highfrequency heating had a very limited impact on PMSEs when the UHF electron density was enhanced because of energetic particle *** addition,an updated qualitative method was used to study the relationship between volume reflectivity and *** volume reflectivity was found to be inversely proportional to the fourth power of radar *** theoretical and experimental results provide a definitive data foundation for further analysis and investigation of the physical mechanism of PMSEs.

关键词： Polar mesosphere summer echoes artificial electron heating volume reflectivity energetic particle precipitation

Investigation of PMSE echoes characteristics using the discontinuous EISCAT UHF observation and its relation with space environment

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Advances in Polar Science 2019年第2期30卷 132-138页

作者： Abdur RAUF LI Hailong Safi ULLAH wang maoyan MENG Lin School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu 610054 China School of Physics University of Electronic Science and Technology of China Chengdu 610054 China

The observations of Polar Mesosphere Summer Echoes (PMSE) were carried out using the sporadic data of EISCAT UHF radar during the summer season from 2004 to 2015. There were 25 h of PMSE echoes with EISCAT UHF radar. PMSE echoes were mostly observed only during the early morning and fore-noon time. Moreover, the PMSE echoes are positively correlated with Lymanα radiation, but the correlation is non-significant. The occurrence of PMSE echoes in the early morning and fore-noon time and there positive correlation with Lymanαradiation suggests that solar radiations might be one important factor for PMSE echoes in this study. Very weak positive, but statistically non-significant correlation is found between PMSE occurrence rate and the local geomagneticK-indices. It is found that there is a matching between the variation in the occurrence rate of PMSE and noctilucent clouds (NLC) up to some extent and they are positively correlated. This positive correlation might support the earlier proposed idea about the role of ice particle size in producing PMSE echoes at higher frequencies.

关键词： PMSE echoes geomagnetic indices EISCAT UHF radar

Comparison of the reaction of polar mesosphere winter echoes and polar mesosphere summer echoes to high-frequency heating in terms of modulated characteristics

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Earth and Planetary Physics 2023年第2期7卷 247-256页

作者： Safi Ullah HaiLong Li Abdur Rauf Shahid Ullah Khan Sufyan Ullah Khan ShuCan Ge Bin wang maoyan wang Lin Meng School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China Department of Physics Riphah International University Islamabad CampusIslamabad 45210Pakistan Department of Physics University of Science and Technology BannuBannu 28101Pakistan National Key Laboratory of Electromagnetic Environment China Research Institute of Radiowave PropagationQingdao 266107China School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China

In this work,for the first time,we have analyzed and compared the responses of polar mesosphere winter echoes(PMWE)and their summer counterpart,polar mesosphere summer echoes(PMSE),to high-frequency(HF)heating in terms of modulated characteristics(i.e.,backscatter intensity reduction,recovery,and overshoot).Both PMWE and PMSE observations were from the same site(Tromsφ,Norway;69.6°N,19.2°E)and radar(EISCAT[European Incoherent Scatter Scientific Association]very high frequency,224 MHz).The heating patterns of both PMWE and PMSE were found to be similar;however,PMSE was more greatly affected by HF *** mesosphere summer echoes showed recovery and overshoot more frequently than did *** addition,the mean recovery and overshoot of PMSE were greater than those of *** associated electron temperature enhancement was estimated for both PMWE and PMSE and showed that,compared with PMWE,the electron temperature enhancement was more significant in *** strong heating effects on PMSE may be due to the considerable increase in electron temperature.

关键词： polar mesosphere winter echo polar mesosphere summer echo electromagnetic wave heating experiment dusty plasma ionosphere

Preface to integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

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Science China Earth Sciences 2024年第4期67卷 895-898页

作者： Shuzhong SHEN Lin DING maoyan ZHU Xiangdong wang Tao DENG State Key Laboratory for Mineral Deposits Research School of Earth Sciences and Engineering and Frontiers Science Center for Critical Earth Material CyclingNanjing UniversityNanjing 210023China State Key Laboratory of Tibetan Plateau Earth System Resources and EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and PalaeoenvironmentChinese Academy of SciencesNanjing 210008China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044China

The Qinghai-Tibetan Plateau(QTP)is well known as the Roof of the World,the Third Pole and the Asian Water *** spans a vast area from the Pamir Plateau in the west to the Longmenshan-Hengduan Mountains in the east,from the Himalaya Mountains in the south to the Kunlun-Qilian Mountains in the *** stretches approximately 1,200 km from north to south and 2,500 km from east to *** did the QTP start to uplift?This is still controversial between early and late Cenozoic *** some scholars advocated its uplift since the India-Asia continental collision at about 65 million years ago in the Paleogene(e.g.,Ding et al.,2017,2022),and the others suggested its uplift since the Miocene(Zheng and Wu,2018).

关键词： uplift Tibetan north

Characteristic analysis of layered PMSEs measured with different elevation angles at VHF based on an experimental case

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地球与行星物理：英文版 2021年第1期5卷 42-51页

作者： ShuCan Ge HaiLong Li Bin Xu Tong Xu Lin Meng maoyan wang Abdel Hannachi MengYan Zhu Lina Broman Safi Ullah Abdur Rauf School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China National Key Laboratory of Electromagnetic Environment China Research Institute of Radiowave PropagationQingdao 266107China School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China Department of Meteorology Stockholm UniversityStockholm SE-106-91Sweden

Polar Mesosphere Summer Echoes(PMSEs)are very strong radar echoes observed at altitudes near the polar summer *** of the essential properties of these radar echoes is that they can give useful diagnostic information about the physics of the scattering *** this paper,the related characteristics of PMSEs measured with the European Incoherent SCATter Very High Frequency(EISCAT VHF)224 MHz radar on 13–15 July 2010 are studied at different elevation angles from 78°to 90°.It is found that the PMSEs peak power and strongest PMSEs average power occur at the same elevation *** interesting is that the strongest PMSEs occur at off-vertical angles when a PMSEs has a layered(multilayer)*** reflection may have more significant effects on PMSEs when there are double or multilayer *** explanations regarding these observations are discussed.

关键词： Polar Mesosphere Summer Echoes off-vertical angles layered structure