Frontiers in Astronomy and Space Sciences最新文献_第5页

Complementary interstellar detections from the heliotail 来自日冕星尾的星际互补探测

Frontiers in Astronomy and Space Sciences Pub Date : 2024-02-08 DOI: 10.3389/fspas.2023.1163519

Sarah A. Spitzer, M. Kornbleuth, M. Opher, J. Gilbert, J. M. Raines, S. Lepri

{"title":"Complementary interstellar detections from the heliotail","authors":"Sarah A. Spitzer, M. Kornbleuth, M. Opher, J. Gilbert, J. M. Raines, S. Lepri","doi":"10.3389/fspas.2023.1163519","DOIUrl":"https://doi.org/10.3389/fspas.2023.1163519","url":null,"abstract":"The heliosphere is a protective shield around the solar system created by the Sun’s interaction with the local interstellar medium (LISM) through the solar wind, transients, and interplanetary magnetic field. The shape of the heliosphere is directly linked with interactions with the surrounding LISM, in turn affecting the space environment within the heliosphere. Understanding the shape of the heliosphere, the LISM properties, and their interactions is critical for understanding the impacts within the solar system and for understanding other astrospheres. Understanding the shape of the heliosphere requires an understanding of the heliotail, as the shape is highly dependent upon the heliotail and its LISM interactions. The heliotail additionally presents an opportunity for more direct in situ measurement of interstellar particles from within the heliosphere, given the likelihood of magnetic reconnection and turbulent mixing between the LISM and the heliotail. Measurements in the heliotail should be made of pickup ions, energetic neutral atoms, low energy neutrals, and cosmic rays, as well as interstellar ions that may be injected into the heliosphere through processes such as magnetic reconnection, which can create a direct magnetic link from the LISM into the heliosphere. The Interstellar Probe mission is an ideal opportunity for measurement either along a trajectory passing through the heliotail, via the flank, or by use of a pair of spacecraft that explore the heliosphere both tailward and noseward to yield a more complete picture of the shape of the heliosphere and to help us better understand its interactions with the LISM.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139794001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of the astrometric capability of Multi-Channel Imager and simulated calculation of proper motion of M31 评估多通道成像仪的天体测量能力并模拟计算 M31 的正确运动

Frontiers in Astronomy and Space Sciences Pub Date : 2024-02-07 DOI: 10.3389/fspas.2024.1250571

Wenfeng Fang, Yong Yu, Xiyan Peng, Zhaojun Yan, Yanzhen Hao, Huanyuan Shan, Zhaoxiang Qi, Shilong Liao, Zhenghong Tang, Qiqi Wu, Zhe-Quan Fu

{"title":"Evaluation of the astrometric capability of Multi-Channel Imager and simulated calculation of proper motion of M31","authors":"Wenfeng Fang, Yong Yu, Xiyan Peng, Zhaojun Yan, Yanzhen Hao, Huanyuan Shan, Zhaoxiang Qi, Shilong Liao, Zhenghong Tang, Qiqi Wu, Zhe-Quan Fu","doi":"10.3389/fspas.2024.1250571","DOIUrl":"https://doi.org/10.3389/fspas.2024.1250571","url":null,"abstract":"Introduction: The Multi-Channel Imager (MCI), one of the back-end modules of the future China Space Station Telescope (CSST), is designed for high-precision spacebased astronomical observations. This paper evaluates the astrometric capability of the MCI based on simulated observational images and Gaia data: the M31 galaxy is selected as a representative case to validate the astrometric capability by calculating the proper motions (PMs) of the M31 member stars.Method: We analyze the stellar centroids of the simulated images in the R, I and G bands, positional uncertainty of 2.5 mas for brighter foreground reference stars from the Gaia DR3 catalog and of 7.5 mas for the fainter M31 member stars, are adopted respectively. The theoretical PMs are generated from the adopted velocity field model, rotation curve, and stellar surface density profile. And the simulated observed PMs are generated from the aforementioned position uncertainties and theoretical PMs.Result: We conclude that the precision of the MCI derived PMs strongly depends on the number of astrometric epochs per year. Specifically, uncertainty of 10 μas/yr is achievable with 10 epochs per year, and of 5 μas/yr with 50 epochs ignoring possible systematic effects. And symmetrically distributed observed fields yield better M31 kinematic parameters.Discussion: Unknown systematic errors, space environment effects on detectors, dithering strategies, and observation schedules can affect the PMs of M31, the above issues need further analysis and validation in future work.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"43 11-12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139856950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluation of the astrometric capability of Multi-Channel Imager and simulated calculation of proper motion of M31 评估多通道成像仪的天体测量能力并模拟计算 M31 的正确运动

Frontiers in Astronomy and Space Sciences Pub Date : 2024-02-07 DOI: 10.3389/fspas.2024.1250571

Wenfeng Fang, Yong Yu, Xiyan Peng, Zhaojun Yan, Yanzhen Hao, Huanyuan Shan, Zhaoxiang Qi, Shilong Liao, Zhenghong Tang, Qiqi Wu, Zhe-Quan Fu

{"title":"Evaluation of the astrometric capability of Multi-Channel Imager and simulated calculation of proper motion of M31","authors":"Wenfeng Fang, Yong Yu, Xiyan Peng, Zhaojun Yan, Yanzhen Hao, Huanyuan Shan, Zhaoxiang Qi, Shilong Liao, Zhenghong Tang, Qiqi Wu, Zhe-Quan Fu","doi":"10.3389/fspas.2024.1250571","DOIUrl":"https://doi.org/10.3389/fspas.2024.1250571","url":null,"abstract":"Introduction: The Multi-Channel Imager (MCI), one of the back-end modules of the future China Space Station Telescope (CSST), is designed for high-precision spacebased astronomical observations. This paper evaluates the astrometric capability of the MCI based on simulated observational images and Gaia data: the M31 galaxy is selected as a representative case to validate the astrometric capability by calculating the proper motions (PMs) of the M31 member stars.Method: We analyze the stellar centroids of the simulated images in the R, I and G bands, positional uncertainty of 2.5 mas for brighter foreground reference stars from the Gaia DR3 catalog and of 7.5 mas for the fainter M31 member stars, are adopted respectively. The theoretical PMs are generated from the adopted velocity field model, rotation curve, and stellar surface density profile. And the simulated observed PMs are generated from the aforementioned position uncertainties and theoretical PMs.Result: We conclude that the precision of the MCI derived PMs strongly depends on the number of astrometric epochs per year. Specifically, uncertainty of 10 μas/yr is achievable with 10 epochs per year, and of 5 μas/yr with 50 epochs ignoring possible systematic effects. And symmetrically distributed observed fields yield better M31 kinematic parameters.Discussion: Unknown systematic errors, space environment effects on detectors, dithering strategies, and observation schedules can affect the PMs of M31, the above issues need further analysis and validation in future work.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"15 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139797140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multi-process driven unusually large equatorial perturbation electric fields during the April 2023 geomagnetic storm 2023 年 4 月地磁暴期间多过程驱动的异常大赤道扰动电场

Frontiers in Astronomy and Space Sciences Pub Date : 2024-02-06 DOI: 10.3389/fspas.2024.1351735

B. Fejer, Sophia R. Laranja, Percy Condor

{"title":"Multi-process driven unusually large equatorial perturbation electric fields during the April 2023 geomagnetic storm","authors":"B. Fejer, Sophia R. Laranja, Percy Condor","doi":"10.3389/fspas.2024.1351735","DOIUrl":"https://doi.org/10.3389/fspas.2024.1351735","url":null,"abstract":"The low latitude ionosphere and thermosphere are strongly disturbed during and shortly after geomagnetic storms. We use novel Jicamarca radar measurements, ACE satellite solar wind, and SuperMAG geomagnetic field observations to study the electrodynamic response of the equatorial ionosphere to the 23, 24 April 2023 geomagnetic storm. We also compare our data with results from previous experimental and modeling studies of equatorial storm-time electrodynamics. We show, for the first time, unusually large equatorial vertical and zonal plasma drift (zonal and meridional electric field) perturbations driven simultaneously by multi storm-time electric field mechanisms during both the storm main and recovery phases. These include daytime undershielding and overshielding prompt penetration electric fields driven by solar wind electric fields and dynamic pressure changes, substorms, as well as disturbance dynamo electric fields, which are not well reproduced by current empirical models. Our nighttime measurements, over an extended period of large and slowly decreasing southward IMF Bz, show very large, substorm-driven, vertical and zonal drift fluctuations superposed on large undershield driven upward and westward drifts up to about 01 LT, and the occurrence of equatorial spread F irregularities with very strong spatial and temporal structuring. These nighttime observations cannot be explained by present models of equatorial storm-time electrodynamics.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"45 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139859706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multi-process driven unusually large equatorial perturbation electric fields during the April 2023 geomagnetic storm 2023 年 4 月地磁暴期间多过程驱动的异常大赤道扰动电场

Frontiers in Astronomy and Space Sciences Pub Date : 2024-02-06 DOI: 10.3389/fspas.2024.1351735

B. Fejer, Sophia R. Laranja, Percy Condor

{"title":"Multi-process driven unusually large equatorial perturbation electric fields during the April 2023 geomagnetic storm","authors":"B. Fejer, Sophia R. Laranja, Percy Condor","doi":"10.3389/fspas.2024.1351735","DOIUrl":"https://doi.org/10.3389/fspas.2024.1351735","url":null,"abstract":"The low latitude ionosphere and thermosphere are strongly disturbed during and shortly after geomagnetic storms. We use novel Jicamarca radar measurements, ACE satellite solar wind, and SuperMAG geomagnetic field observations to study the electrodynamic response of the equatorial ionosphere to the 23, 24 April 2023 geomagnetic storm. We also compare our data with results from previous experimental and modeling studies of equatorial storm-time electrodynamics. We show, for the first time, unusually large equatorial vertical and zonal plasma drift (zonal and meridional electric field) perturbations driven simultaneously by multi storm-time electric field mechanisms during both the storm main and recovery phases. These include daytime undershielding and overshielding prompt penetration electric fields driven by solar wind electric fields and dynamic pressure changes, substorms, as well as disturbance dynamo electric fields, which are not well reproduced by current empirical models. Our nighttime measurements, over an extended period of large and slowly decreasing southward IMF Bz, show very large, substorm-driven, vertical and zonal drift fluctuations superposed on large undershield driven upward and westward drifts up to about 01 LT, and the occurrence of equatorial spread F irregularities with very strong spatial and temporal structuring. These nighttime observations cannot be explained by present models of equatorial storm-time electrodynamics.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"67 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139799779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Statistical analysis of overlapping double ion energy dispersion events in the northern cusp 北部尖顶重叠双离子能量弥散事件的统计分析

Frontiers in Astronomy and Space Sciences Pub Date : 2024-01-12 DOI: 10.3389/fspas.2023.1228475

D. E. da Silva, L. J. Chen, S. Fuselier, S. Petrinec, K. Trattner, G. Cucho-Padin, H. K. Connor, B. L. Burkholder, A. J. Huntenburg

{"title":"Statistical analysis of overlapping double ion energy dispersion events in the northern cusp","authors":"D. E. da Silva, L. J. Chen, S. Fuselier, S. Petrinec, K. Trattner, G. Cucho-Padin, H. K. Connor, B. L. Burkholder, A. J. Huntenburg","doi":"10.3389/fspas.2023.1228475","DOIUrl":"https://doi.org/10.3389/fspas.2023.1228475","url":null,"abstract":"This article presents a statistical analysis of overlapping double ion-energy dispersion events in the northern cusp (“double dispersion”). Double dispersion in either cusp is a phenomenon associated with multiple reconnections occurring on the dayside magnetosphere as a result of its constant interaction with the variable solar wind. Using observations from a low Earth orbiting (LEO) Defense Meteorological Satellite Program (DMSP) satellite, we analyze 138 dayside events selected by the automatic algorithm extended from our previous work. We conducted a correlation study between the number of detected double dispersion events and 1) the month of the year to analyze the seasonal response of the cusp, and 2) solar wind interplanetary magnetic field (IMF) components and clock/cone angles to investigate its relationship with magnetic reconnection. We found that dispersion events occur more frequently during the northern summer months (i.e., when the dipole is tilted Sunward) and when the By component of IMF is positive. In addition, we provide a machine-readable list of the events and the code used to automatically detect the events.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"45 17","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139533519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Artificial intelligence in remote sensing geomorphology—a critical study 遥感地貌学中的人工智能--一项重要研究

Frontiers in Astronomy and Space Sciences Pub Date : 2023-11-30 DOI: 10.3389/fspas.2023.1176325

Urs Mall, Daniel Kloskowski, Philip Laserstein

{"title":"Artificial intelligence in remote sensing geomorphology—a critical study","authors":"Urs Mall, Daniel Kloskowski, Philip Laserstein","doi":"10.3389/fspas.2023.1176325","DOIUrl":"https://doi.org/10.3389/fspas.2023.1176325","url":null,"abstract":"Planetary geomorphological maps over a wide range of spatial and temporal scales provide important information on landforms and their evolution. The process of producing a geomorphological map is extremely time-consuming and maps are often difficult to reproduce. The success of deep learning and machine learning promises to drastically reduce the cost of producing these maps and also to increase their reproducibility. However, deep learning methods strongly rely on having sufficient ground truth data to recognize the wanted surface features. In this study, we investigate the results from an artificial intelligence (AI)–based workflow to recognize lunar boulders on images taken from a lunar orbiter to produce a global lunar map showing all boulders that have left a track in the lunar regolith. We compare the findings from the AI study with the results found by a human analyst (HA) who was handed an identical database of images to identify boulders with tracks on the images. The comparison involved 181 lunar craters from all over the lunar surface. Our results show that the AI workflow used grossly underestimates the number of identified boulders on the images that were used. The AI approach found less than one fifth of all boulders identified by the HA. The purpose of this work is not to quantify the absolute sensitivities of the two approaches but to identify the cause and origin for the differences that the two approaches deliver and make recommendations as to how the machine learning approach under the given constraints can be improved. Our research makes the case that despite the increasing ease with which deep learning methods can be applied to existing data sets, a more thorough and critical assessment of the AI results is required to ensure that future network architectures can produce the reliable geomorphological maps that these methods are capable of delivering.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139201317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Numerical simulation of the equatorial plasma bubble: the effect of seeding by the vertical winds and random background noise perturbations 赤道等离子体气泡的数值模拟：垂直风和随机背景噪声扰动的影响

Frontiers in Astronomy and Space Sciences Pub Date : 2023-11-28 DOI: 10.3389/fspas.2023.1320570

Yunzhou Zhu, Q. Tang, Tong Xu, Yi Liu, Chen Zhou, Zhongxin Deng, Yuqiang Zhang, Zhengyu Zhao, Fengsi Wei, Bin Xu, Shuji Sun

{"title":"Numerical simulation of the equatorial plasma bubble: the effect of seeding by the vertical winds and random background noise perturbations","authors":"Yunzhou Zhu, Q. Tang, Tong Xu, Yi Liu, Chen Zhou, Zhongxin Deng, Yuqiang Zhang, Zhengyu Zhao, Fengsi Wei, Bin Xu, Shuji Sun","doi":"10.3389/fspas.2023.1320570","DOIUrl":"https://doi.org/10.3389/fspas.2023.1320570","url":null,"abstract":"A wide variety of small-amplitude waves widely exist in the ionosphere and have significant effects on the evolution of equatorial plasma bubbles. In this paper, we simulated equatorial plasma bubbles (EPB) seeded by vertical neutral wind perturbations with wavelengths of 125 km and 250 km, and compared the morphology characteristics of plasma bubble structures with those under random noise perturbations in the background density. The numerical results showed that both vertical winds and random background noise perturbations can contribute to the growth of plasma bubbles, and the perturbations under additional random background noise can promote the growth of the plasma bubble structures faster. Additionally, several processes of the nonlinear behavior of bifurcated EPB structures, including bifurcation, pinching, and small-scale turbulent structures, were successfully obtained. Our simulation captured supersonic flows within the low-density plasma structures characterized by vertical velocities of about 1.5 km/s, which is consistent with experimental studies found in the literature.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"29 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139224175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The effects of particle injections on the ring current development during the 7-8 September 2017 geomagnetic storm 2017 年 9 月 7-8 日地磁风暴期间粒子注入对环流发展的影响

Frontiers in Astronomy and Space Sciences Pub Date : 2023-11-28 DOI: 10.3389/fspas.2023.1278820

C. Ferradas, M.-C. Fok, N. Maruyama, M. G. Henderson, S. Califf, S. A. Thaller, B. T. Kress

{"title":"The effects of particle injections on the ring current development during the 7-8 September 2017 geomagnetic storm","authors":"C. Ferradas, M.-C. Fok, N. Maruyama, M. G. Henderson, S. Califf, S. A. Thaller, B. T. Kress","doi":"10.3389/fspas.2023.1278820","DOIUrl":"https://doi.org/10.3389/fspas.2023.1278820","url":null,"abstract":"In this study we investigate the role of particle injections on the ring current development during the 7-8 September 2017 geomagnetic storm by applying a temporally and spatially varying data-driven outer boundary condition in numerical simulations of the ring current with the Comprehensive Inner Magnetosphere-Ionosphere model. We quantify the role of particle injections by comparing the results from two simulation runs: one with the model outer boundary condition defined by measurements at their original time cadence, namely, 1.5 min, and one with the same boundary condition smoothed in time with a 2-h running average window. The comparison between these two runs reveals that the observed particle injections enhanced the electric field remarkably, which had a significant effect on the ring current development, namely, they 1) strengthened the ring current, 2) skewed the ring current distribution dawnward, 3) delayed the formation of the symmetric ring current by prolonging the duration of the partial ring current, and 4) caused a O+-richer ring current with a O+ dominant ring current distribution at the inner edge. Furthermore, these effects enhanced the energy deposition to the plasmasphere and ionosphere via heating by the ring current ions.","PeriodicalId":507437,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139220236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Editorial: Space- and ground-based observations of ELF (extremely low frequency)/VLF (very low frequency) electromagnetic waves and their propagation mechanisms 社论：ELF（极低频）/VLF（甚低频）电磁波的天基和地基观测及其传播机制

Frontiers in Astronomy and Space Sciences Pub Date : 2023-11-23 DOI: 10.3389/fspas.2023.1335615

Shufan Zhao, Xuhui Shen, Chen Zhou, Zhiyang Xia, Huaiyun Peng, Li Liao

引用次数: 0