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Towards win-win: weighted-Voronoi-diagram based channel quantization for security enhancement in downlink cloud-RAN with limited CSI feedback

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Science China(Information Sciences) 2017年第4期60卷 32-48页

作者： Dongyang XU Pinyi REN Qinghe DU Li SUN yichen wang School of Electronic and Information Engineering Xi'an Jiaotong University

Physical layer(PHY) security is recently proved to enable improving the security of wireless communication networks. In downlink frequency division duplex(FDD) cloud radio access network(C-RAN), the performance of PHY security highly relies on the channel state information(CSI) which is usually acquired through the codebook-quantization-based technique at the transceiver. However, the conventional quantization method aggravates the leakage of privacy information in C-RAN under the eavesdropping environment. In this paper, a novel channel quantization method is investigated to improve the secrecy-rate performance of C-RAN by exploiting the high-dimension space geometry. Based on this method, it is proved that when the statistical distribution of the channel matrices of both the legitimate user and the eavesdropper is exploited, a win-win situation can be created where secrecy-rate gains are improved without sacrificing beamforming gains from the point of view of ergodic rate. Particularly, a secrecy-oriented criterion is devised to implement the proposed method for generating codebooks. Then a weighted Voronoi diagram(WVD) is formulated on the complex Grassmann manifold and finally, a vector quantization based algorithm is proposed to build up novel quantization codebooks iteratively. Simulation results further validate the superiority of our proposed codebooks over conventional codebooks in C-RAN systems.

关键词： C-RAN virtualization physical layer security Grassmann manifold channel quantization

Modeling and physical mechanism analysis of the effect of a polycrystalline-ferroelectric gate on FE-FinFETs

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Science China(Information Sciences) 2023年第5期66卷 305-306页

作者： Chengxu wang Hao YU yichen wang Zichong ZHANG Xiangshui MIAO Xingsheng wang School of Optical and Electronic Information Huazhong University of Science and Technology Hubei Yangtze Memory Laboratories School of Integrated Circuits Huazhong University of Science and Technology Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology

Due to its potential in low-power computing or storage applications, the Hf O2-based ferroelectric (FE) field-efect transistor (FET), which consists of a MOSFET and an FE gate dielectric stack on the top of the original gate, has attracted massive research interest in the past decade [1].Taking advantage of the scalability of FE Hf O2-based film [2], FE-FETs have been developing high-performance computing and high-density memory at advanced process nodes [3]. However, significant variations in state-of-the-art FE-Fin FETs are also caused by polycrystalline FE gates.

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Ablation behaviour of(Hf-Ta-Zr-Nb)C high entropy carbide ceramic at temperatures above 2100℃

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Journal of Materials Science & Technology 2022年第18期113卷 40-47页

作者： yichen wang Buhao Zhang Chengyu Zhang Jie Yin Michael J.Reece School of Engineering and Materials Science Queen Mary University of LondonMile End RoadLondon E14NSUnited Kingdom State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China School of Materials Science and Engineering Northwestern Polytechnical UniversityXi’anShaanxi 710072China

The ablation behaviour of(Hf-Ta-Zr-Nb)C high entropy carbide(HEC4)was studied at temperatures above 2100℃using a plasma flame gun in *** microstructures,phase and chemical compositions of the HEC4 samples were investigated after *** mass ablation rate of the HEC4 samples increased with increasing ablation time from 0.21 mg cm^(−2)s^(−1)for 60 s to 0.45 mg cm^(−2)s^(−1)for 120 ***-pared to the mono-and binary carbides with commonly decreased mass and thickness after ablation,the HEC4 samples with the increased mass and thickness after ablation showed good resistance to mechan-ical scouring at such high temperatures and an oxidation controlled ablation *** ablation processes mainly include the oxidation of the carbide,the phase separation of the oxides,the melting of oxides,and the diffusion of oxygen.A composition gradient in the oxide layer was detected due to the different melting temperatures of the different oxides;Nb-Ta rich oxides formed at the front surface melted and became enriched at the edge of the samples,and the Zr-Hf rich oxides were enriched in the centre of the *** oxide layer with complex compositions and phase distributions acted as an effective ablation barrier.

关键词： High entropy carbides Transition metal carbides Ultra-high temperature ceramics Ablation resistance

Aerosol composition,sources,and secondary processing during autumn at a regional site in the Beijing-Tianjin-Hebei region

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Particuology 2023年第4期75卷 177-184页

作者： yichen wang Qiyuan wang Jie Tian Yong Zhang Yunfei Wu Weikang Ran Renjian Zhang Junji Cao School of Public Policy and Administration Northwestern Polytechnical UniversityXi'an710129China Key Laboratory of Aerosol Chemistry and Physics State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an710061China CAS Center for Excellence in Quaternary Science and Global Change Xi'an710061China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing100029China Xianghe Observatoryof Whole Atmosphere Institute of Atmospheric PhysicsChinese Academy of SciencesXianghe CountyHebei Province065400China

Air pollution is serious during autumn in the Beijing-Tianjin-Hebei(BTH)region,but there are few studies that have utilized real-time observations and source apportionment of the autumn submicron aerosols in this *** this study,a quadrupole aerosol chemical speciation monitor(Q-ACSM)was deployed for the real-time measurement of the non-refractory compositions of submicron aerosols(NR-PM1)at a regional site(Xianghe)from October 3 to November 14,*** results showed that nitrate was the largest inorganic aerosol,and the oxygenated organic aerosol(OOA)was the largest organic aerosol in ***-like OA(HOA)was the largest organic aerosol When the NR-PM1 mass concentrations increased from the lowest to the highest bins,nitrate and biomass burning OA(BBOA)showed increasing trends in the suburban *** nitrate formation during the pollution epi-sodes resulted from both photochemical and aqueous *** reduce the particulate matter(PM2.5)concentrations and eliminate heavy pollution episodes,control measures should focus on reducing NO_(x),NH_(3),and volatile organic compound(VOCs)emissions.

关键词： Autumn Beijing-Tianjin-Hebei region Submicron aerosol Organic sources Control measures

An updated constraint on the local stratigraphy at the Chang'E-4 landing site

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Earth and Planetary Physics 2021年第1期5卷 19-31页

作者： YiRen Chang ZhiYong Xiao yichen wang ChunYu Ding Jun Cui YuZhen Cai State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China Planetary Environmental and Astrobiological Research Laboratory School of Atmospheric SciencesSun Yat-sen UniversityZhuhaiGuangdong 519000China Center for Excellence in Comparative Planetology Chinese Academy of SciencesHefei 230000China National Astronomical Observations of China Chinese Academy of SciencesBeijing 100000China

The Chang’E-4 mission has been exploring the lunar *** scientific targets of the rover onboard are(1)resolving the possible mineralogy related to the South Pole-Aitken basin and(2)understanding the subsurface processes at the lunar *** to date that are based on the reflectance spectra and radar data obtained by the rover have shown a persistent inconsistency about the local *** explain both the abnormal surface topography at the landing site and the unexpected radargram observed by the rover,the Alder crater has been frequently reported to be older than the mare basalts at that landing ***,this argument is not supported by earlier geological mapping nor recent crater *** this controversy is critical for a full understanding of the geological history of the landing area and for correct interpretations of the scientific data *** detailed crater statistics,rigorous statistical analyses,and an updated crater chronology function,this study is determined to resolve the relative ages of the Alder crater,Finsen crater,and the mare basalts on the floor of Von Kármá*** results reveal that while background secondaries and local resurfacing have widely occurred in the study area,affecting age determinations,the statistics are significant enough to conclude that the Alder crater is the oldest among the three *** independent constraint is consistent with both the crosscutting relationships of different terrains in this area and global stratigraphic *** results exclude Alder as a possible contributor of the post-mare deposits at the landing site,appealing for a more systematic stratigraphy study to resolve the provenances of these deposits.

关键词： Moon Chang'E-4 impact craters absolute model age stratigraphy

Role of nitric oxide in the genotoxic response to chronic microcystin-LR exposure in human–hamster hybrid cells

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Journal of Environmental Sciences 2015年第3期27卷 210-218页

作者： Xiaofei wang Pei Huang Yun Liu Hua Du Xinan wang Meimei wang yichen wang Tom K.Hei Lijun Wu An Xu Key Laboratory of Ion Beam Bioengineering Hefei Institutes of Physical Science Chinese Academy of Sciences Institute of Intelligent Machines Hefei Institutes of Physical Science Chinese Academy of Sciences Center for Radiological Research College of Physicians & Surgeons Columbia University

Microcystin-LR （MC-LR） is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen （Group 2B） by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human-hamster hybrid （AL） cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher （p 〈 0.01） in AL ceUs exposed to a cytotoxic concentration （1 μmol/L） of MC-LR for 30 days than in untreated control ceils, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide （NO） production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor NC-methyl-L-arginine （L-NMMA）, which suppressed MC-LR- induced mutations as well. The survival of mitochondrial DNA-depleted （pO） AL ceils was markedly decreased by MC-LR treatment compared to that in AL cells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.

关键词： Microcystin-LR (MC-LR) Chronic exposure Genotoxicity Nitric oxide

Geological Context of the SLIM Landing Site

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Journal of Earth Science 2024年第2期35卷 708-711页

作者： yichen wang Zhiyong Xiao Pei Ma Hanxing Ouyang Wei Cao Planetary Environmental and Astrobiological Research Laboratory School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519000China Chinese Academy of Sciences Center for Excellence in Comparative Planetology Hefei 230026China Planetary Science Institute School of Earth SciencesChina University of GeoscienceWuhan 430074China

INTRODUCTION Japan’s first successful lunar landing mission,Smart Lander for Investigating Moon(SLIM),was landed on the Moon on January 19th,*** made a precise landing within 100 m of the targeted landing zone(central coordinates 13.316°S,25.251°E),which is located around the Shioli crater(D=270 m,central coordinates as 13.33°S,25.23°E)in the southwestern ejecta of the Theophilus crater(D=98.6 km,central coordinates as 11.45°S,26.28°E).

关键词： southwestern coordinates SLIM

High-resolution anatomical and spatial transcriptome analyses reveal two types of meristematic cell pools within the secondary vascular tissue of poplar stem

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Molecular Plant 2023年第5期16卷 809-828页

作者： Juan Du yichen wang Wenfan Chen Mingling Xu Ruhong Zhou Huixia Shou Jun Chen State Key Laboratory of Plant Physiology and Biochemistry College of Life SciencesZhejang University866Yu Hangtang RoadHangzhouZhejiang 310058China MOE Key Laboratory of Biosystems Homeostasis&Protection College of Life SciencesZhejang University866 Yu Hangtang RoadHangzhouZhejang 310058China Institute of Quantitative Biology College of Life SciencesZhejiang UniversityHangzhouZhejiang 310058China Hangzhou Botanical Garden Taoyuanling RoadHangzhouZhejiang 310013China

The secondary vascular tissue emanating from meristems is central to understanding how vascular plants such as forest trees evolve,grow,and regulate secondary radial ***,the overall molecular characterization of meristem origins and developmental trajectories from primary to secondary vascular tissues in woody tree stems is technically *** this study,we combined high-resolution anatomic analysis with a spatial transcriptome(ST)technique to define features of meristematic cells in a developmental gradient from primary to secondary vascular tissues in poplar *** tissue-specific gene expression of meristems and derived vascular tissue types were accordingly mapped to specific anatomical *** analyses were used to track the origins and changes of meristems throughout the development from primary to secondary vascular ***,two types of meristematic-like cell pools within secondary vascular tissues were inferred based on high-resolution microscopy combined with ST,and the results were confirmed by in situ hybridization of,transgenic trees,and single-cell *** rectangle shape procambium-like(PCL)cells develop from procambium meristematic cells and are located within the phloem domain to produce phloem cells,whereas fusiform shape cambium zone(CZ)meristematic cells develop from fusiform metacambium meristematic cells and are located inside the CZ to produce xylem *** gene expression atlas and transcriptional networks spanning the primary transition to secondary vascular tissues generated in this work provide new resources for studying the regulation of meristem activities and the evolution of vascular plants.A web server(https://***/stRNAPal/)was also established to facilitate the use of ST RNA-seq data.

关键词： poplar stem primary and secondary meristem primary and secondary vascular tissue spatial transcriptome single-cell sequencing

Super-resolution diffractive neural network for alloptical direction of arrival estimation beyond diffraction limits

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Light(Science & Applications) 2024年第8期13卷 1602-1614页

作者： Sheng Gao Hang Chen yichen wang Zhengyang Duan Haiou Zhang Zhi Sun Yuan Shen Xing Lin Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China

Wireless sensing of the wave propagation direction from radio sources lays the foundation for communication,radar,navigation,***,the existing signal processing paradigm for the direction of arrival estimation requires the radio frequency electronic circuit to demodulate and sample the multichannel baseband signals followed by a complicated computing process,which places the fundamental limit on its sensing speed and energy ***,we propose the super-resolution diffractive neural networks(S-DNN)to process electromagnetic(EM)waves directly for the DOA estimation at the speed of *** multilayer meta-structures of S-DNN generate super-oscillatory angular responses in local angular regions that can perform the all-optical DOA estimation with angular resolutions beyond the diffraction *** spatial-temporal multiplexing of passive and reconfigurable S-DNNs is utilized to achieve high-resolution DOA estimation over a wide field of *** S-DNN is validated for the DOA estimation of multiple radio sources over 5 GHz frequency bandwidth with estimation latency over two to four orders of magnitude lower than the state-of-the-art commercial devices in *** results achieve the angular resolution over an order of magnitude,experimentally demonstrated with four times,higher than diffraction-limited *** also apply S-DNN’s edge computing capability,assisted by reconfigurable intelligent surfaces,for extremely low-latency integrated sensing and communication with low power *** work is a significant step towards utilizing photonic computing processors to facilitate various wireless sensing and communication tasks with advantages in both computing paradigms and performance over electronic computing.

关键词： beyond optical network