Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065228
Y. Mao, Jinxiang Wan, Si Li, Qingpeng Zhang
Previously, we designed an effective SIABC, which significantly reduces the thickness of the absorption boundary compared with the traditional PML boundary condition. The use of SIABC requires a long distance between the scatterer and the boundary, which increases the memory and running time of the program to a certain extent. The sub grid technology alleviates this problem by setting the area near the scatterer as a fine grid area and other areas as a coarse grid area, so as to reduce the number of grids to be calculated in the whole area. We build a simple two-dimensional model and apply sub grid technology for simulation. The simulated results are compared with those of different grid sizes. It is found that the simulation accuracy is basically the same as that of full fine grid, and the calculation time is greatly shortened. The results show that the combination of sub grid technology and SIABC is a promising FDTD simulation method.
{"title":"Subgrid Surface Impedance Absorbing Boundary Condition for FDTD Method","authors":"Y. Mao, Jinxiang Wan, Si Li, Qingpeng Zhang","doi":"10.1109/ACES-China56081.2022.10065228","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065228","url":null,"abstract":"Previously, we designed an effective SIABC, which significantly reduces the thickness of the absorption boundary compared with the traditional PML boundary condition. The use of SIABC requires a long distance between the scatterer and the boundary, which increases the memory and running time of the program to a certain extent. The sub grid technology alleviates this problem by setting the area near the scatterer as a fine grid area and other areas as a coarse grid area, so as to reduce the number of grids to be calculated in the whole area. We build a simple two-dimensional model and apply sub grid technology for simulation. The simulated results are compared with those of different grid sizes. It is found that the simulation accuracy is basically the same as that of full fine grid, and the calculation time is greatly shortened. The results show that the combination of sub grid technology and SIABC is a promising FDTD simulation method.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133770548","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065292
Sissi Wang, Qun Yan Zhou, J. Dai, Q. Cheng
For decades, metamaterials have been widely investigated for their excellent feature of fashioning the spatial electromagnetic (EM) waves. Moreover, to control the EM waves in a digitally discretized manner, the concepts of the digital coding metamaterial and programmable metamaterial were proposed in 2014. However, most time, the reconfigurable function of the coding metamaterials is realized by electricity through active elements, such as PIN diodes. Here, we introduce another driving manner, liquid-metal-based mechanical driving, to the coding metamaterial system. In general, liquid-metal-based coding metamaterials have two main distinguishing features: 1) they can implement reconfigurable states continuously owing to the fluidity; 2) they can get rid of the mechanical fatigue and damage due to the flexibility of liquid metal and its containers. In the paper, we begin by designing a liquid-metal-based meta-atom with the characteristics of broadband reconfiguration, multi-bit coding and wide-angle incidence. Then, the designed meta-atoms are spatially arranged to realize the applications of broadband beam-steering and broadband RCS reduction.
{"title":"Electromagnetic Wave Manipulations via Liquid-metal-based Coding Metamaterial System","authors":"Sissi Wang, Qun Yan Zhou, J. Dai, Q. Cheng","doi":"10.1109/ACES-China56081.2022.10065292","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065292","url":null,"abstract":"For decades, metamaterials have been widely investigated for their excellent feature of fashioning the spatial electromagnetic (EM) waves. Moreover, to control the EM waves in a digitally discretized manner, the concepts of the digital coding metamaterial and programmable metamaterial were proposed in 2014. However, most time, the reconfigurable function of the coding metamaterials is realized by electricity through active elements, such as PIN diodes. Here, we introduce another driving manner, liquid-metal-based mechanical driving, to the coding metamaterial system. In general, liquid-metal-based coding metamaterials have two main distinguishing features: 1) they can implement reconfigurable states continuously owing to the fluidity; 2) they can get rid of the mechanical fatigue and damage due to the flexibility of liquid metal and its containers. In the paper, we begin by designing a liquid-metal-based meta-atom with the characteristics of broadband reconfiguration, multi-bit coding and wide-angle incidence. Then, the designed meta-atoms are spatially arranged to realize the applications of broadband beam-steering and broadband RCS reduction.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133785721","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10064873
Dongyu Li, Feng Gao, Guangli Yang
A novel method to enhance the wide-angle scanning capability (WASC) of the array antenna is introduced in this letter, where can reduce the inter-element mutual coupling of the array and broaden the beam-width of the element in the array. Because of the bent metal plates, the horizontal and vertical currents are produced in the element of the array, which can extend the beam-width of the element in the array. Meanwhile, the decoupling function can be realized by the converse vertical currents from the adjacent antenna elements. Two 1×8 linear arrays are fabricated and tested to demonstrate the proposed method. The measured antenna performance accords with the simulated performance. The proposed array can scan the coverage of ±60° with a realized gain variation under 3 dB and lower side lobe level (SLL) under -7.9dB within the operating band from 4.5 to 5.0 GHz. Therefore, the proposed method has been demonstrated in the linear array and can be promoted to apply in the planar array for wireless communication systems, especially in the large coverage communication system.
{"title":"A Novel Dual-Functional Method for Wide-Angle Scanning Phased Array","authors":"Dongyu Li, Feng Gao, Guangli Yang","doi":"10.1109/ACES-China56081.2022.10064873","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10064873","url":null,"abstract":"A novel method to enhance the wide-angle scanning capability (WASC) of the array antenna is introduced in this letter, where can reduce the inter-element mutual coupling of the array and broaden the beam-width of the element in the array. Because of the bent metal plates, the horizontal and vertical currents are produced in the element of the array, which can extend the beam-width of the element in the array. Meanwhile, the decoupling function can be realized by the converse vertical currents from the adjacent antenna elements. Two 1×8 linear arrays are fabricated and tested to demonstrate the proposed method. The measured antenna performance accords with the simulated performance. The proposed array can scan the coverage of ±60° with a realized gain variation under 3 dB and lower side lobe level (SLL) under -7.9dB within the operating band from 4.5 to 5.0 GHz. Therefore, the proposed method has been demonstrated in the linear array and can be promoted to apply in the planar array for wireless communication systems, especially in the large coverage communication system.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115406106","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065134
Yuqing Zheng, Xiaofeng Ai, Zhiming Xu, F. Zhao, Yong Yang
Forward scatter radar (FSR) can achieve target detection by capturing the signal disturbance caused by the target crossing the baseline. Firstly, the FSR network based on the global navigation satellite system (GNSS) is constructed, and the basic conditions that constitute forward scattering are analyzed. Then, considering the satellite motion, a dynamic echo model is given. Finally, the influence of target parameters on the echo characteristics is analyzed by simulation. The feasibility of target detection based on GNSS-FSR is proved, and the work can provide a foundation for target detection and recognition of the FSR network.
{"title":"Characteristics Analysis on Dynamic Forward Scattering Echoes","authors":"Yuqing Zheng, Xiaofeng Ai, Zhiming Xu, F. Zhao, Yong Yang","doi":"10.1109/ACES-China56081.2022.10065134","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065134","url":null,"abstract":"Forward scatter radar (FSR) can achieve target detection by capturing the signal disturbance caused by the target crossing the baseline. Firstly, the FSR network based on the global navigation satellite system (GNSS) is constructed, and the basic conditions that constitute forward scattering are analyzed. Then, considering the satellite motion, a dynamic echo model is given. Finally, the influence of target parameters on the echo characteristics is analyzed by simulation. The feasibility of target detection based on GNSS-FSR is proved, and the work can provide a foundation for target detection and recognition of the FSR network.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"235 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115578970","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065190
Jialin Shi, Xiuming Xu, T. Jiang
In the article, the introduction of the robot-type three-notch antenna will be discussed. The antenna is printed on a dielectric substrate made of FR-4. The electromagnetic simulation software HFSS is used for modeling and analysis. and other methods to expand the bandwidth, the use of slotting and the introduction of branches. The bandwidth of the antenna is 3.5GHz-21GHz, and the maximum gain of the antenna is 5.78dB. The three notches are 5GHz-WLAN, 7/8GHz X-band uplink and downlink, and 12-14GHz of satellite communication Ku-band. The antenna has achieved the trend of miniaturization in the current era, and the size of the antenna is only $24.4ast23.38ast1.6mm^{3}$.
{"title":"Robot-Type Miniaturized Planar Ultra-Wideband Triple-Notch Antenna","authors":"Jialin Shi, Xiuming Xu, T. Jiang","doi":"10.1109/ACES-China56081.2022.10065190","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065190","url":null,"abstract":"In the article, the introduction of the robot-type three-notch antenna will be discussed. The antenna is printed on a dielectric substrate made of FR-4. The electromagnetic simulation software HFSS is used for modeling and analysis. and other methods to expand the bandwidth, the use of slotting and the introduction of branches. The bandwidth of the antenna is 3.5GHz-21GHz, and the maximum gain of the antenna is 5.78dB. The three notches are 5GHz-WLAN, 7/8GHz X-band uplink and downlink, and 12-14GHz of satellite communication Ku-band. The antenna has achieved the trend of miniaturization in the current era, and the size of the antenna is only $24.4ast23.38ast1.6mm^{3}$.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116823545","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065002
Lan Dong, Tao Wang, Daiyin Zhu
Highly squinted spotlight SAR has played an important role in military and civilian fields, with its fine two-dimensional resolution and the possibility of day and night operation in all weather. This paper proposes the architecture of four DSPs for real-time imaging, which includes the modified polar format algorithm imaging, phase gradient autofocus, geometric distortion correction, and image quantization. In the final experiment verification part, an image of 2048*2048 pixels can be processed within 0.62s, proving its validity and efficient handling.
{"title":"Highly Squinted Spotlight SAR Imaging Based On Four DSPs","authors":"Lan Dong, Tao Wang, Daiyin Zhu","doi":"10.1109/ACES-China56081.2022.10065002","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065002","url":null,"abstract":"Highly squinted spotlight SAR has played an important role in military and civilian fields, with its fine two-dimensional resolution and the possibility of day and night operation in all weather. This paper proposes the architecture of four DSPs for real-time imaging, which includes the modified polar format algorithm imaging, phase gradient autofocus, geometric distortion correction, and image quantization. In the final experiment verification part, an image of 2048*2048 pixels can be processed within 0.62s, proving its validity and efficient handling.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116917029","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065064
Yujie Wang, Qian Yuan, Pei-bai Zhou, Zi He, L. Zha, D. Ding, Li Li, Yuanyuan Wen, Dawei Song, S. Shang
A new acceleration method is proposed for efficiently solving the electromagnetic scattering from metal targets in half-space. In order to further speed up the calculation efficiency, an efficient three-dimensional spatial interpolation method is introduced for half-space Green’s function. Tabulation and IDW interpolations are performed on the Sommerfeld integrals for the half-space Green’s function. The efficiency can be improved 20 times higher than that of the traditional combined field integral equation(CFIE). Numerical results show that this method can significantly reduce the filling time of impedance matrix and maintain high accuracy.
{"title":"Electromagnetic scattering from metal targets in half-space environment with three-dimensional spatial interpolation method","authors":"Yujie Wang, Qian Yuan, Pei-bai Zhou, Zi He, L. Zha, D. Ding, Li Li, Yuanyuan Wen, Dawei Song, S. Shang","doi":"10.1109/ACES-China56081.2022.10065064","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065064","url":null,"abstract":"A new acceleration method is proposed for efficiently solving the electromagnetic scattering from metal targets in half-space. In order to further speed up the calculation efficiency, an efficient three-dimensional spatial interpolation method is introduced for half-space Green’s function. Tabulation and IDW interpolations are performed on the Sommerfeld integrals for the half-space Green’s function. The efficiency can be improved 20 times higher than that of the traditional combined field integral equation(CFIE). Numerical results show that this method can significantly reduce the filling time of impedance matrix and maintain high accuracy.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116011752","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065060
Tianhao Han, Biao Dong, Jinhua Feng, Yu Wang, Zhongming Yan
A novel structure of magnetoelectric (ME) antenna based on multiferroic materials is proposed in this paper. The structure consists of two layers. Its bottom layer and top layer are made of piezoelectric material and magnetostrictive material respectively, and a tapered slot is designed on the top layer. The easy axes of magnetization of the two areas of magnetostrictive material are antiparallel. The ME antenna with this structure has different near-field radiation characteristics from the reported ME antennas, and shows directional radiation characteristics.
{"title":"A Novel Structure of Magnetoelectric Antenna Based on Multiferroic Materials","authors":"Tianhao Han, Biao Dong, Jinhua Feng, Yu Wang, Zhongming Yan","doi":"10.1109/ACES-China56081.2022.10065060","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065060","url":null,"abstract":"A novel structure of magnetoelectric (ME) antenna based on multiferroic materials is proposed in this paper. The structure consists of two layers. Its bottom layer and top layer are made of piezoelectric material and magnetostrictive material respectively, and a tapered slot is designed on the top layer. The easy axes of magnetization of the two areas of magnetostrictive material are antiparallel. The ME antenna with this structure has different near-field radiation characteristics from the reported ME antennas, and shows directional radiation characteristics.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123423818","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065127
Jianzhou Li, Shuhui Chen, Haixuan Zhang, Chaoqun Fan, Lu Liu
Wings of flying targets vibrate due to the influence of external factors. This phenomenon is more pronounced for large wings and there will be detailed features that affect the micro-motion characteristics. The electromagnetic scattering characteristic of this kind of micro-motion of wings in actual flight is of great significance to target recognition and identification. This paper focuses on the modeling and analysis of the micro-motion characteristics and detailed features due to vibration and deformation. Firstly, the mathematical geometric model of wing vibration was established. Then the according to scattering field is simulated, and a time-frequency analysis was performed on the results. Micro-Doppler features different from conventional results were observed in the result. Starting from the detailed feature in spanwise, chordwise, and airfoil, the vibration modeling study of wings was carried out. Eventually, it was found that the twist of the airfoil caused this phenomenon.
{"title":"Detailed Features Modeling of Vibrating Wing’s Micro-Motion Characteristics","authors":"Jianzhou Li, Shuhui Chen, Haixuan Zhang, Chaoqun Fan, Lu Liu","doi":"10.1109/ACES-China56081.2022.10065127","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065127","url":null,"abstract":"Wings of flying targets vibrate due to the influence of external factors. This phenomenon is more pronounced for large wings and there will be detailed features that affect the micro-motion characteristics. The electromagnetic scattering characteristic of this kind of micro-motion of wings in actual flight is of great significance to target recognition and identification. This paper focuses on the modeling and analysis of the micro-motion characteristics and detailed features due to vibration and deformation. Firstly, the mathematical geometric model of wing vibration was established. Then the according to scattering field is simulated, and a time-frequency analysis was performed on the results. Micro-Doppler features different from conventional results were observed in the result. Starting from the detailed feature in spanwise, chordwise, and airfoil, the vibration modeling study of wings was carried out. Eventually, it was found that the twist of the airfoil caused this phenomenon.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123656394","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}
Pub Date : 2022-12-09DOI: 10.1109/ACES-China56081.2022.10065053
Xin Yi Liu, Z. Jia, H. Zhang, Ying Liu, W. E. Sha, L. Jiang
An electromagnetic-thermal co-simulation method is proposed for microstrip filter in this paper. The Maxwell equation is solved by discontinuous Galerkin time-domain (DGTD) method, while thermal simulation is carried out based on finite-element time-domain (FETD) method. Electromagnetic and thermal simulations are coupled by power loss and temperature-dependent conductivity. At last, the method is applied to analyze the microstrip low-pass filter.
{"title":"Electromagnetic-Thermal Co-simulation of Microstrip Filter","authors":"Xin Yi Liu, Z. Jia, H. Zhang, Ying Liu, W. E. Sha, L. Jiang","doi":"10.1109/ACES-China56081.2022.10065053","DOIUrl":"https://doi.org/10.1109/ACES-China56081.2022.10065053","url":null,"abstract":"An electromagnetic-thermal co-simulation method is proposed for microstrip filter in this paper. The Maxwell equation is solved by discontinuous Galerkin time-domain (DGTD) method, while thermal simulation is carried out based on finite-element time-domain (FETD) method. Electromagnetic and thermal simulations are coupled by power loss and temperature-dependent conductivity. At last, the method is applied to analyze the microstrip low-pass filter.","PeriodicalId":293734,"journal":{"name":"2022 International Applied Computational Electromagnetics Society Symposium (ACES-China)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123957345","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：