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A GNSS Anti-Spoofing Technique Based on the Spatial Distribution Characteristic of the Residual Vectors

Tsinghua Science and Technology 2024年第2期29卷 457-468页

作者： Qi'an wu xiaowei Cui Mingquan Lu Pengxiang Yang Peng wu Department of Electronic Enginnering Tsinghua UniversityBeijing 100084China Xi’an Modern Control Technology Research Institute Xi’an 710065China

Anti-spoofing is becoming a crucial technique for applications with high navigation accuracy and reliability requirements.Anti-spoofing technique based on Receiver Autonomous Integrity Monitoring(RAIM)is a good choice for most Global Navigation Satellite System(GNSS)receivers because it does not require any change to the hardware of the receiver.However,the conventional RAIM method can only detect and mitigate a single spoofing signal.Some improved RAIM methods can deal with more spoofing signals,but the computational complexity increases dramatically when the number of satellites in view increase or need additional information.This paper proposes a new RAIM method,called the SRV-RAIM method,which has a very low computation complexity regardless of the number of satellites in view and can deal with any number of spoofing signals.The key to the new method is the spatial distribution characteristic of the Satellites'Residual Vectors(SRV).In replay or generative spoofing scenarios,the pseudorange measurements of spoofing signals are consistent,the residual vectors of real satellites and those of spoofing satellites have good separation characteristics in spatial distribution.Based on this characteristic,the SRV-RAIM method is proposed,and the simulation results show that the method can separate the real signals and the spoofing signals with an average probability of 86.55%in the case of 12 visible satellites,regardless of the number of spoofing signals.Compared to the conventional traversal-RAIM method,the performance is only reduced by 3.59%,but the computational cost is reduced by 98.3%,so most of the GNSS receivers can run the SRV-RAIM algorithm in time.

关键词： Global Navigation Satellite System(GNSS) anti-spoofing Receiver Autonomous Integrity Monitoring(RAIM) Satellites'Residual Vectors(SRV)

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The development of collagen based composite scaffolds for bone regeneration

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Bioactive Materials 2018年第1期3卷 129-138页

作者： Dawei Zhang Xiaowei Wu Jingdi Chen Kaili Lin School&Hospital of Stomatology Tongji UniversityShanghai Engineering Research Center of Tooth Restoration and RegenerationShanghai 200072China Institute of Biomedical and Pharmaceutical Technology Fuzhou UniversityFuzhou 350002China

Bone is consisted of bone matrix,cells and bioactive factors,and bone matrix is the combination of inorganic minerals and organic polymers.Type I collagen fibril made of five triple-helical collagen chains is the main organic polymer in bone matrix.It plays an important role in the bone formation and remodeling process.Moreover,collagen is one of the most commonly used scaffold materials for bone tissue engineering due to its excellent biocompatibility and biodegradability.However,the low mechanical strength and osteoinductivity of collagen limit its wider applications in bone regeneration field.By incorporating different biomaterials,the properties such as porosity,structural stability,osteoinductivity,osteogenicity of collagen matrixes can be largely improved.This review summarizes and categorizes different kinds of biomaterials including bioceramic,carbon and polymer materials used as components to fabricate collagen based composite scaffolds for bone regeneration.Moreover,the possible directions of future research and development in this field are also proposed.

关键词： Collagen Bone regeneration Composite scaffolds Biomaterials Tissue engineering

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Light-, Middle- and Heavy-Lanthanide Ate-Complexes Bearing Ln(Ⅲ)-Si bonds: Structural, Spectroscopic, and Bonding Analysis

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Chinese Journal of Chemistry 2023年第22期41卷 2995-3002,I0002页

作者： xiaowei Pan Changjiang wu Huayi Fang Chunhua Yan School of Materials Science and Engineering Tianjin Key Lab for Rare Earth Materials and ApplicationsNankai University Tianjin300350China Shanghai Zhitong Construction Engineering Technology Co. Ltd.Shanghai 204433China College of Chemistry and Chemical Engineering Lanzhou UniversityLanzhouGansu 730000China

Recent decades have witnessed a rapid development of the lanthanide silicon chemistry.In this research,by reacting[(THF)_(3)LisiPh_(3)]with Cp_(3)Ln(Ⅰ)(THF)(Ln(I)=Sm(Ⅰ),Tb(Ⅱ),Dy(Ⅰ),Yb(Ⅰ)or Cp_(2)Lu(Ⅱ)CI(THF),a series of middle-and heavy-lanthanocene monosilyl/disilyl ate-complexes([(DME)_(3)Lil[Cp_(3)Ln(Ⅱ)SiPh_(3)]and[(DME)_(3)Li[Cp_(2)Lu(Ⅱ)(SiPh_(3))_(2)])were synthesized.The structures of the obtained lanthanocene monosilyl/disilyl ate-complexes were determined by single crystal X-ray diffraction.Together with the previously reported[(DME)_(3)Li[Cp_(3)La(Ⅱ)SiPh_(3)]and[(DME);Lil[Cp_(3)Ce(Ⅱ)SiPha],a complex group comprising silyl light-,middle-and heavy-lanthanocene with identical core coordination pattern are presented.

关键词： Lanthanide ate-complex Silyl ligand Lanthanide-silicon bond Structure elucidation Density functional calculations Metallocenes

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Iron isotope fractionation during fenitization:a case study of carbonatite dykes from Bayan Obo,Inner Mongolia,China

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Acta Geochimica 2022年第5期41卷 789-793页

作者： Zongyi wu Jian Sun xiaowei Li Xiangkun Zhu Institute of Geology MNR Key Laboratory of Deep-Earth DynamicsChinese Academy of Geological Sciences MNR Key Laboratory of Isotope Geology100037 BeijingPR China State Key Laboratory of Geological Processes and Mineral Resources School of Earth Science and ResourcesUniversity of Geosciences100083 BeijingChina

As a powerful tracer in high-temperature geochemistry,Fe isotopes have been studied for their behaviour during fl uid exsolution and evolution related to felsic magma system,but that for carbonatite magma system remains unknown.Here we study the Fe isotope fractionation behaviour during fenitization–processes that widely occur associated with carbonatite or alkaline intrusions.Nine fenite/carbonatite samples from carbonatite dykes at Bayan Obo area are analyzed for their Fe isotope compositions as well as elemental compositions.Combined with previous reported carbonatite δ^(56)Fe data,the results show that carbonatites range from-0.35‰to 0.28‰,with an average of-0.10‰in δ^(56)Fe values,while fenites range from-0.17‰to 0.30‰,with an average of 0.11‰in δ^(56)Fe values.This indicates that fenitizing fl uids exsolved from carbonatite melts are enriched in heavier Fe isotopes.Such a Fe isotope fractionation trend is diff erent from that for fl uid exsolution from felsic magmatism.δ^(56)Fe values in fenites are negatively correlated with indicators of fenitization intensity such as(Na+K),Ti,Ba,Th,Nb,U or Pb abundances,likely refl ecting that Fe isotopes fractionate during the evolution of the fenitizing fl uids.Thus,Fe isotopes are a valuable tool for tracing fl uid exsolution and evolution relevant to carbonatite magmatism and related metal mineralization.

关键词： Iron isotopes Fenitization Fluid exsolution Carbonatite Bayan Obo

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Study on damage mechanism and damage distribution of the rear plate under impact of debris cloud

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Defence Technology（防务技术） 2024年第5期35卷 151-167页

作者： Chenyang wu xiaowei Chen Qiguang He State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyHaidian DistrictBeijing 100081China School of Mechatronical Engineering Beijing Institute of TechnologyHaidian DistrictBeijing 100081China Institute of Fluid Physics China Academy of Engineering PhysicsMianyang 621900SichuanChina

The debris cloud generated by the hypervelocity impact(HVI)of orbiting space debris directly threatens the spacecraft.A full understanding of the damage mechanism of rear plate is useful for the optimal design of protective structures.In this study,the hypervelocity yaw impact of a cylindrical aluminum projectile on a double-layer aluminum plate is simulated by the FE-SPH adaptive method,and the damage process of the rear plate under the impact of the debris cloud is analyzed based on the debris cloud structure.The damage process can be divided into the main impact stage of the debris cloud and the structural response of the rear plate.The main impact stage lasts a short time and is the basis of the rear plate damage.In the stage of structure response,the continuous deformation and inertial motion of the rear plate dominate the perforation of the rear plate.We further analyze the damage mechanism and damage distribution characteristics of the rear plate in detail.Moreover,the connection between velocity space and position space of the debris cloud is established,which promotes the general analysis of the damage law of debris cloud.Based on the relationship,the features of typical damage areas are identified by the localized fine analysis.Both the cumulative effect and structural response cause the perforation of rear plate;in the non-perforated area,cratering by the impact of hazardous fragments is the main damage mode of the rear plate.

关键词： Damage of rear plate Debris cloud Secondary impact Hypervelocity yaw impact FE-SPH adaptive method

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Analysis of the contributions of human factors and natural factors affecting the vegetation pattern in coastal wetlands

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Ecosystem Health and Sustainability 2020年第1期6卷 58-67,57页

作者： Zheng Zang Xiaowei Wu Yun Niu Guangxiong Mao School of Urban and Environmental Sciences Huaiyin Normal UniversityHuai’anJiangsuChina Key Laboratory of Carrying Capacity Assessment for Resource and Environment Ministry of Natural Resources(Chinese Academy of Natural Resource EconomicsChina University of Geosciences BeijingInstitute of Geographical Sciences and Natural Resource Researchthe Chinese Academy of Sciences)BeijingChina Key Laboratory of Coast and Island Development(Nanjing University) Ministry of EducationNanjingJiangsuChina

Introduction:Accurate identification of the dominant factors affecting coastal wetlands can provide a reference for vegetation rehabilitation.In this study,quantitative analysis was performed on the Yancheng coastal wetland using ANOVA and geostatistical methods.Outcomes/other:The results indicated that in the directions perpendicular and parallel to the coastline,the soil moisture and salinity in the study area exhibited relatively significant(p75%)for soil moisture and salinity in the southern experimental zone and southern buffer zone.Conclusion:Compared with the northern study area,the contribution of human disturbance to the spatial heterogeneity of soil moisture and salinity in the southern study area is higher.

关键词： Coastal wetlands vegetation pattern soil moisture soil salinity geostatistical analysis

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Toward Sustainable Revegetation in the Loess Plateau Using Coupled Water and Carbon Management

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Engineering 2022年第8期8卷 143-153页

作者： Fubo Zhao Yiping wu xiaowei Yin Georgii Alexandrov Linjing Qiu Department of Earth and Environmental Science School of Human Settlements and Civil EngineeringXi’an Jiaotong UniversityXi’an 710049China A.M.Obukhov Institute of Atmospheric Physics Russian Academy of SciencesMoscow 119017Russia

The"Grain-for-Green"project on the Loess Plateau is the largest revegetation program in the world.However,revegetation-induced land use changes can influence both water and carbon cycles,and the diverse consequences were not well understood.Therefore,the reasonability and sustainability of revegetation measures are in question.This study quantifies the impacts of revegetation-induced land use conversions on the water and carbon cycles in a typical watershed on the Loess Plateau and identifies suitable areas where revegetation of forest or grassland could benefit both soil and water conservation and carbon sequestration.We used a coupled hydro-biogeochemical model to simulate the changes of a few key components in terms of water and carbon by designing a variety of hypothetical land use conversion scenarios derived from revegetation policy.Compared to the baseline condition(land use in 2000),both sediment yield and water yield decreased substantially when replacing steep cropland with forest or grassland.Converting cropland with slopes larger than 25°,15°,and 6°to forest(CTF)would enhance the carbon sequestration with a negligible negative effect on soil water content,while replacing cropland with grassland(CTG)would result in a decline in net primary production but with a substantial increase in soil water content(3.8%-14.9%).Compared to the baseline,the soil organic carbon would increase by 0.9%-3.2% in CTF and keep relatively stable in CTG.Through testing a variety of hypothetical revegetation scenarios,we identified potential priority areas for CTF and CTG,where revegetation may be appropriate and potentially beneficial to conserving soil and water and enhancing carbon sequestration.Our study highlights the challenges in future water and carbon coupling management under revegetation policy,and our quantitative results and identification of potential areas for revegetation could provide information to policy makers for seeking optimal management on the Loess Plateau.

关键词： Carbon Land use change Loess Plateau Sediment SWAT-Day Cent Water resources

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Placement of unmanned aerial vehicles as communication relays in two-tiered multi-agent system:clustering based methods

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Journal of Systems Engineering and Electronics 2020年第2期31卷 231-242页

作者： wu Gaofeng WAN Kaifang GAO Xiaoguang FU xiaowei School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710129China

The network performance and the unmanned aerial vehicle(UAV)number are important objectives when UAVs are placed as communication relays to enhance the multi-agent information exchange.The problem is a non-deterministic polynomial hard(NP-hard)multi-objective optimization problem,instead of generating a Pareto solution,this work focuses on considering both objectives at the same level so as to achieve a balanced solution between them.Based on the property that agents connected to the same UAV are a cluster,two clustering-based algorithms,M-K-means(MKM)and modified fast search and find density of peaks(MFSFDP)methods,are first proposed.Since the former algorithm requires too much computational time and the latter one requires too many relays,an algorithm for the balanced network performance and relay number(BPN)is proposed by discretizing the area to avoid missing the optimal relay positions and defining a new local density function to reflect the network performance metric.Simulation results demonstrate that the proposed algorithms are feasible and effective.Comparisons between these algorithms show that the BPN algorithm uses fewer relay UAVs than the MFSFDP and classic set-covering based algorithm,and its computational time is far less than the MKM algorithm.

关键词： unmanned aerial vehicle(UAV) relay communication clustering relay node placement wireless network

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COVID-19: Antiviral Agents, Antibody Development and Traditional Chinese Medicine

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Virologica Sinica 2020年第6期35卷 685-698页

作者： Wenyi Guan Wendong Lan Jing Zhang Shan Zhao Junxian Ou Xiaowei Wu Yuqian Yan Jianguo wu Qiwei Zhang Guangdong Provincial Key Laboratory of Tropical Disease Research School of Public HealthSouthern Medical UniversityGuangzhou 510515China Guangdong Provincial Key Laboratory of Virology Institute of Medical MicrobiologyJinan UniversityGuangzhou 510632GuangdongChina

The World Health Organization(WHO) has declared coronavirus disease 2019(COVID-19) is the first pandemic caused by coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2). Currently, there is no effective anti-SARS-CoV-2 drug approved worldwide for treatment of patients with COVID-19. Therapeutic options in response to the COVID-19 outbreak are urgently needed. To facilitate the better and faster development of therapeutic COVID-19 drugs, we present an overview of the global promising therapeutic drugs, including repurposing existing antiviral agents,network-based pharmacology research, antibody development and traditional Chinese medicine. Among all these drugs,we focus on the most promising drugs(such as favipiravir, tocilizumab, SARS-CoV-2 convalescent plasma, hydroxychloroquine, Lianhua Qingwen, interferon beta-1 a, remdesivir, etc.) that have or will enter the final stage of human testing—phase Ⅲ–Ⅳ clinical trials.

关键词： Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) Coronavirus disease 2019(COVID-19) Updates Drug repositioning Network-based pharmacology Antibody Traditional Chinese medicine

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Last glacial terrestrial vegetation record of leaf wax n-alkanols in the northern South China Sea:Contrast to scenarios from longchain n-alkanes

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Acta Oceanologica Sinica 2022年第8期41卷 22-30页

作者： Shengyi Mao Guodong Jia xiaowei Zhu Nengyou wu Daidai wu Hongxiang Guan Lihua Liu CAS Key Laboratory of Gas Hydrate Guangzhou Institute of Energy ConversionChinese Academy of SciencesGuangzhou 510640China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Key Laboratory of Gas Hydrate of Ministry of Natural Resources Qingdao Institute of Marine GeologyQingdao 266237China Laboratory for Marine Mineral Resources Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China

Long-chain n-alkanols and n-alkanes in core sediments from the northern South China Sea(SCS)were measured to make a comparison during terrestrial vegetation reconstruction from~42 ka to~7 ka.The results showed that terrestrial vegetation record from long-chain n-alkanes matched well with previous studies in nearby cores,showing that more C_(4)plants developed during the Last Glacial Maximum(LGM)and C_(3)plants dominated in the interglacial period.However,these scenarios were not revealed by terrestrial vegetation reconstruction using long-chain n-alkanols,which showed C_(3)plant expansion during the LGM.The discrepancy during the interglacial period could be attributed to the aerobic degradation of functionalized long-chain n-alkanols in the oxygen-rich bottom water,resulting in poor preservation of terrestrial vegetation signals.On the other hand,the different advantages of functionalized n-alkanols and non-functional n-alkanes to record local and distal vegetation signals,respectively,may offer a potential explanation for the contradiction during the LGM when the SCS was characterized by low-oxygen deep water.Nevertheless,large variations on n-alkyl lipid compositions in C_(3)/C_(4)plants could play a part in modulating sedimentary long-chain n-alkanols and n-alkanes toward different vegetation signals,thereby suggesting that caution must be taken in respect to the terrestrial vegetation reconstruction using long-chain n-alkanes and long-chain n-alkanols.

关键词： South China Sea long-chain n-alkanols long-chain n-alkanes Last Glacial Maximum terrestrial vegetation record

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