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| 1 | Precise orbit determination of Beidou Satellites with precise positioning显示文摘Chinese Beidou satellite navigation system constellation currently consists of eight Beidou satellites and can provide preliminary service of navigation and positioning in the Asia-Pacific Region.Based on the self-developed software Position And Navigation Data Analysis(PANDA) and Beidou Experimental Tracking Stations (BETS),which are built by Wuhan University,the study of Beidou precise orbit determination,static precise point positioning (PPP),and high precision relative positioning,and differential positioning are carried out comprehensively.Results show that the radial precision of the Beidou satellite orbit determination is better than 10 centimeters.The RMS of static PPP can reach several centimeters to even millimeters for baseline relative positioning.The precision of kinematic pseudo-range differential positioning and RTK mode positioning are 2-4 m and 5-10 cm respectively,which are close to the level of GPS precise positioning.Research in this paper verifies that,with support of ground reference station network,Beidou satellite navigation system can provide precise positioning from several decimeters to meters in the wide area and several centimeters in the regional area.These promising results would be helpful for the implementation and applications of Beidou satellite navigation system. | SHI Chuang ZHAO QiLe LI Min TANG WeiMing HU ZhiGang LOU YiDong ZHANG HongPing NIU XiaoJi LIU JingNan | 2012 | Science China Earth Sciences2012,55,7: | 61 |
| 2 | Quality assessment of onboard GPS receiver and its combination with DORIS and SLR for Haiyang 2A precise orbit determination显示文摘The GPS,DORIS,and SLR instruments are installed on Haiyang 2A(HY2A)altimetry satellite for Precise Orbit Determination(POD).Among these instruments,the codeless GPS receiver is the state-of-art Chinese indigenous onboard receiver,and it is the first one successfully used for Low Earth Orbit(LEO)satellite.Firstly,the contribution assesses the performance of the receiver through an analysis of data integrity,numbers of all tracked and valid measurements as well as multipath errors.The receiver generally shows good performance and quality despite a few flaws.For example,L2 observations are often missing in low elevations,particularly during the ascent of GPS satellites,and the multipath errors of P1 show a slightly abnormal pattern.Secondly,the PCO(Phase Center Offset)and PCV(Phase Center Variation)of the antenna of the GPS receiver are determined in this contribution.A significant leap for Z-component of PCO up to-1.2 cm has been found on 10 October 2011.Thirdly,the obtained PCO and PCV maps are used for GPS only POD solutions.The post-fit residuals of ionosphere-free phase combinations reduce almost 50%,and the radial orbit differences with respect to CNES(Centre National d’Etudes Spatiales)Precise Orbit Ephemeris(POEs)improve about 13.9%.The orbits are validated using the SLR data,and the RMS of SLR Observed minus Computed(O-C)residuals reduces from 17.5 to 15.9 mm.These improvements are with respect to the orbits determined without PCO and PCV.Fourthly,six types of solutions are determined for HY2A satellite using different combinations of GPS,DORIS,and SLR data.Statistics of SLR O-C residuals and cross-comparison of orbits obtained in the contribution and the CNES POEs indicate that the radial accuracy of these orbits is at the 1.0 cm level for HY2A orbit solutions,which is much better than the scientific requirements of this mission.It is noticed that the GPS observations dominate the achievable accuracy of POD,and the combination of multiple types of observations can reduce orbit errors caused by data gaps and maintain more stable and continuous orbits. | GUO Jing ZHAO QiLe GUO Xiang LIU XiangLin LIU JingNan ZHOU Quan | 2015 | Science China Earth Sciences2015,58,1: | 13 |
| 3 | Data Logic Structure and Key Technologies on Intelligent High-precision Map显示文摘Taking autonomous driving and driverless as the research object,we discuss and define intelligent high-precision map.Intelligent high-precision map is considered as a key link of future travel,a carrier of real-time perception of traffic resources in the entire space-time range,and the criterion for the operation and control of the whole process of the vehicle.As a new form of map,it has distinctive features in terms of cartography theory and application requirements compared with traditional navigation electronic maps.Thus,it is necessary to analyze and discuss its key features and problems to promote the development of research and application of intelligent high-precision map.Accordingly,we propose an information transmission model based on the cartography theory and combine the wheeled robot’s control flow in practical application.Next,we put forward the data logic structure of intelligent high-precision map,and analyze its application in autonomous driving.Then,we summarize the computing mode of“Crowdsourcing+Edge-Cloud Collaborative Computing”,and carry out key technical analysis on how to improve the quality of crowdsourced data.We also analyze the effective application scenarios of intelligent high-precision map in the future.Finally,we present some thoughts and suggestions for the future development of this field. | Jingnan LIU Jiao ZHAN Chi GUO Tingting LEI Ying LI | 2020 | Journal of Geodesy and Geoinformation Science2020,3,3: | 11 |
| 4 | 11.2% Efficiency all-polymer solar cells with high open-circuit voltage显示文摘Herein,we fabricated all-polymer solar cells(all-PSCs)based on a fluorinated wide-bandgap p-type conjugated polymer PM6 as the donor,and a narrow bandgap n-type conjugated polymer PZ1 as the acceptor.In addition to the complementary absorption and matching energy levels,the optimized blend films possess high cystallinity,predominantly face-on stacking,and a suitable phase separated morphology.With this active layer,the devices exhibited a high Vocof 0.96 V,a superior Jscof 17.1 mA cm^-2,a fine fill factor(FF)of 68.2%,and thus an excellent power conversion efficiency(PCE)of 11.2%,which is the highest value reported to date for single-junction all-PSCs.Furthermore,the devices showed good storage stability.After 80 d of storage in the N2-filled glovebox,the PCE still remained over 90%of the original value.Large-area devices(1.1 cm^2)also demonstrated an outstanding performance with a PCE of 9.2%,among the highest values for the reported large-area all-PSCs.These results indicate that the PM6:PZ1 blend is a promising candidate for scale-up production of large area high-performance all-PSCs. | Yuan Meng Jingnan Wu Xia Guo Wenyan Su Lei Zhu Jin Fang Zhi-Guo Zhang Feng Liu Maojie Zhang Thomas P. Russell Yongfang Li | 2019 | Science China Chemistry2019,62,7: | 9 |
| 5 | High Precision Orbit Determination of CHAMP Satellite显示文摘The precision orbit determination of challenging minisatellite payload(CHAMP) satellite was done based on position and navigation data analyst(PANDA) software which is developed in Wuhan University, using the onboard GPS data of year 2002 from day 126 to 131. The orbit accuracy was assessed by analyzing the difference from GFZ post-processed science orbits (PSO), the GPS carrier and pseudo-range data residuals and the satellite laser ranging (SLR) residuals. | ZHAO Qile LIU Jingnan GE Maorong | 2006 | Geo-Spatial Information Science2006,9,3: | 9 |
| 6 | Using repeated precise gps campaigns for research of present-day crustal movement and strain in the Qinghai-Tibetan Plateau显示文摘The problem of crustal movement in the Qing-hai-Tibetan Plateau is a hotstopic of the present-day international geodetic world. GPS observations in 1993, 1995 and 1997 are used to survey the three-dimensional displacement of GPS monitoring station in the Qinghai-Tibetan Plateau, and to calculate and analyze the present-day crustal movement and strain in the Qinghai-Tibetan Plateau. The result of repeated campaign shows that the crustal movement in the Qinghai-Tibetan Plateau is still compressing in the north and south directions, extending in the west and east directions, and uplifting in the vertical direction. The relative convergence velocity of the Himalayan block is approximately (19.5±1.7)mm/a, the strain velocity is about (5.5±6.0) mm/a, and the uplifting velocity is some (7.6±5.2) mm/a. The compression velocity of the Tibet block relative to Golmud in the north and south directions is (9.3±4.6) mm/a, the strain velocity of the middle part in the west and east directions is (15.6±6.3) mm/a, | LIU Jingnan XU Caijun SONG Chenghua SHI Chuang JIANG Weiping DONG Lixiang | 2001 | Chinese Science Bulletin2001,46,8: | 8 |
| 7 | The RNA-binding protein QKI5 regulates primary miR-124-1 processing via a distal RNA motif during erythropoiesis显示文摘 | Fang Wang Wei Song Hongmei Zhao Yanni Ma Yuxia Li Di Zhai Jingnan Pi Yanmin Si Jiayue Xu Lei Dong Rui Su Mengmeng Zhang Yong Zhu Xiaoxia Ren Fei Miao Wenjie Liu Feng Li Junwu Zhang Aibin He Ge Shan Jingyi Hui Linfang Wang Jia Yu | 2017 | Cell Research2017,27,3: | 7 |
| 8 | Study on compound ultra-precision alignment technique显示文摘A nano-displacement measurement system with duo-gratings is analyzed by using optics theory,a math- ematic model for the system is established,and the characteristic of laser Moirésignals is studied through CAD simu- lation.To improve signal sensitivity and positioning accuracy,two methods of precision positioning are brought for- ward:differential Moirépositioning method and modified Moirépositioning method.A compound control system for precision positioning is set up by combining these 2 Moiréalignment methods,in which the modified Moiréalignment technique is used for coarse alignment and the differential Moiréalignment technique is used for fine alignment,and the system obtains positioning accuracy of±10 nm in±500μm positioning range with shot response time. | Zhang Jinlong Yang Ankang Liu Jingnan Yoshiyuki Uchidas | 2007 | 仪器仪表学报2007,28,10: | 7 |
| 9 | Time synchronization in communication networks based on the Beidou foundation enhancement system显示文摘Communication networks rely on time synchronization information generated by base station equipment(either the Global Navigation Satellite System receiver or rubidium atomic clock) to enable wireless networking and communications. Meanwhile, the time synchronization among base stations depends on the Network Time Protocol. With the development of mobile communication systems, the corresponding time synchronization accuracy has increased as well. In this case, the use of sparsely distributed-high-precision synchronization points to synchronize time for an entire network with high precision is a key problem and is the foundation of the enhanced network communication. The current receiver equipment for China's digital synchronous network typically includes dedicated multi-channel GPS receivers for communication; however, with the development of GPS by the USA, network security has been destabilized and reliability is low. Nonetheless, network time synchronization based on Beidou satellite navigation system timing devices is an inevitable development trend for China's digital communications network with the establishment of the independently developed BDS, especially the implementation and improvement of the Beidou foundation enhancement system. | LIU Hui ZHANG RuFei LIU JingNan ZHANG Ming | 2016 | Science China(Technological Sciences)2016,59,1: | 7 |
| 10 | Epicenter and magnitude of large earthquake determined from high-rate GPS observations: A case study of the 2008 M8.0 Wenchuan earthquake显示文摘For earthquake and tsunami early warning and emergency response,the earthquake epicenter and magnitude should be determined rapidly and correctly.Using high-rate GPS observations,we can readily obtain precise and high resolution displacement time series and the seismic waveforms during the earthquake.In this paper,a new algorithm is proposed for estimating the earthquake epicenter and magnitude with the seismic waveforms derived from high-rate GPS data during the earthquake.A case study of the 2008 Wenchuan earthquake is conducted from 1 Hz GPS data and the epicenter and magnitude are determined.Compared with the results issued by the China Seismological Bureau,the estimation error of the epicenter and the magnitude is about 12 km and 0.1 magnitude unit,respectively.It has shown that high-rate GPS could be a new tool feasible for estimating the earthquake epicenter and magnitude,independent of or combined with seismometers. | FANG RongXin SHI Chuang WANG GuangXing LIU JingNan | 2014 | Science China Earth Sciences2014,57,7: | 5 |
| 11 | A Non-Fullerene Acceptor with Chlorinated Thienyl Conjugated Side Chains for High-Performance Polymer Solar Cells via Toluene Processing显示文摘Small molecular acceptors(SMAs)BTC-2F and BTH-2F,based on heptacyclic benzodi(cyclopentadithiophene)electron-donating core(CBT)with chlorinated-thienyl conjugated and thienyl conjugated side chains,respectively,are designed and synthesized.Compared with non-chlorine acceptor BTH-2F,BTC-2F exhibits slightly blue-shifted absorption spectra,similar the lowest unoccupied molecular orbital(LUMO)(-3.91 eV);deeper highest occupied molecular orbital(HOMO)energy level and higher electron mobility than that of BTH-2F.PM6,a wide bandgap polymer,is selected as the donor material to construct bulk heterojunction polymer solar cells processed with nonhalogenated solvent toluene.The optimized PM6:BTC-2F-based device presents a 12.9%power conversion efficiency(PCE),while the PCE of PM6:BTH-2F-based device is only 11.3%.The results suggest that it is an effective strategy to optimize the photoelectric properties of SMAs by incorporating chlorine atom into the conjugated side chains. | Cuangwei Li Jingnan Wu Jin Fang Xia Guo Lei Zhu Feng Liu Maojie Zhang Yongfang Li | 2020 | Chinese Journal of Chemistry2020,38,7: | 5 |
| 12 | Estimation of Geodetic Parameters with VLBI Data of Last 5 Years显示文摘The meaning to research the potential of VLBI for geodetic applications is summarized. And the observation models and their related parameters of geodetic interest are investigated. Then, the principle and method of using the random model in VLBI data processing are investigated. With the world wide VLBI data from 2000-2004, the conditions to compute the parameters of geodetic interest are introduced, and so are the computing methods and processes. And the computed results of the parameters of geodetic interest are analyzed. | WEI Erhu LIU Jingnan SHI Chuang | 2007 | Geo-Spatial Information Science2007,10,1: | 4 |
| 13 | Concept of the solar ring mission:An overview显示文摘The concept of the Solar Ring mission was gradually formed from L5/L4 mission concept, and the proposal of its pre-phase study was funded by the National Natural Science Foundation of China in November 2018 and then by the Strategic Priority Program of Chinese Academy of Sciences in space sciences in May 2019. Solar Ring mission will be the first attempt to routinely monitor and study the Sun and inner heliosphere from a full 360-degree perspective in the ecliptic plane. The current preliminary design of the Solar Ring mission is to deploy six spacecraft, grouped in three pairs, on a sub-AU orbit around the Sun. The two spacecraft in each group are separated by about 30?and every two groups by about 120?. This configuration with necessary science payloads will allow us to establish three unprecedented capabilities:(1) determine the photospheric vector magnetic field with unambiguity,(2) provide 360-degree maps of the Sun and the inner heliosphere routinely, and(3) resolve the solar wind structures at multiple scales and multiple longitudes. With these capabilities, the Solar Ring mission aims to address the origin of solar cycle, the origin of solar eruptions, the origin of solar wind structures and the origin of severe space weather events. The successful accomplishment of the mission will advance our understanding of the star and the space environment that hold our life and enhance our capability of expanding the next new territory of human. | WANG YuMing JI HaiSheng WANG YaMin XIA LiDong SHEN ChengLong GUO JingNan ZHANG QuanHao HUANG ZhengHua LIU Kai LI XiaoLei LIU Rui WANG JingXiu WANG Shui | 2020 | Science China(Technological Sciences)2020,63,9: | 4 |
| 14 | Multi-quadric Equations Interpolation and Its Applications to the Establishment of Crustal Movement Speed Field显示文摘In this paper,multi_quadric equations interpolation is used to establish a widely covered and valuable speed field model,with which the crustal movement image is obtained. | YAO Yibin LIU Jingnan SHI Chuang TAO Benzao | 2002 | Geo-Spatial Information Science2002,5,2: | 4 |
| 15 | Incidence and prevalence of moyamoya disease in urban China: a nationwide retrospective cohort study显示文摘Background and objective Moyamoya disease(MMD)is an increasingly recognised cause of stroke,mainly described in East Asia.China is the largest nation in Asia,but few studies reported the epidemiology of MMD,especially at a national level.We aimed to estimate the incidence and prevalence of MMD in China.Methods We performed a population-based study using data from the national databases of Urban Basic Medical Insurance between 2013 and 2016,covering approximately 0.50 billion individuals.MMD cases were identified by diagnostic code(International Classification of Diseases,10th Revision I67.5)or related diagnostic text.Results A total of 1987 MMD patients(mean age 44.45±14.30 years,female-to male ratio 1.12)were identified,representing a national crude incidence of 0.59(95%CI:0.49 to 0.68)and a prevalence of 1.01(95%CI:0.81 to 1.21)per 100000 person-years in 2016.Rates were higher in females than in males for the incidence(0.66 vs 0.52)and prevalence(1.05 vs 0.90).And the age-specific rates showed a bimodal distribution,with the highest peak in middle-aged group and the second peak in child group.Conclusions Our results confirm that MMD is relatively common in East Asians,but the rates in China were lower than those in other East Asian countries such as Japan and Korea.The unique epidemiological features,including a relatively weak female predominance and a shift in the highest peak of incidence from children to adults,revealed new sight into MMD.Further research is expected to explore the potential pathogenesis of MMD. | Yixin Sun Guoyu Zhou Jingnan Feng Lu Chen Guozhen Liu Jinxi Wang Qingliang Wang Junyou Yu Xiwang Yang Zheng Yang Pei Gao Shengfeng Wang Siyan Zhan | 2021 | Stroke & Vascular Neurology2021,6,4: | 4 |
| 16 | Hydrodynamics and bubble behaviour in a three-phase two-stage internal loop airlift reactor显示文摘Local hydrodynamics of a gas–liquid–solid system,such as bubble circulation regime,gas holdup,liquid velocity and axial profile of solid concentration,are studied in a two-stage internal loop airlift reactor.Empirical correlations for gas holdup and liquid velocity are proposed to ease the reactor design and scale-up.Different bubble circulation regimes were displayed in the first(lower) and second(upper) stages.Increasing superficial gas velocity and solid loading can promote regime transition of the second stage,and the gas holdup of the second stage is higher than that of the lower stage.In addition,the effects of solid loading on bubble behaviour are experimentally investigated for each stage.It is found that bubble size in the downcomer decreases with the presence of solid particles,and bubble size distribution widens under higher superficial gas velocity and lower solid loading. | Dan Li Kai Guo Jingnan Li Yiping Huang Junchao Zhou Hui Liu Chunjiang Liu | 2018 | Chinese Journal of Chemical Engineering2018,26,6: | 3 |
| 17 | DETERMINATION OF WEIGHTED MEAN TROPOSPHERIC TEMPERATURE USING GROUND METEOROLOGICAL MEASUREMENTS显示文摘The weighted mean tropospheric temperature is a critical parameter in the conversion of wet zenith delay to precipitable water vapor in GPS Meteorology.This parameter can not be calculated from the radiosonde data in real time through the conventional methods.In this study,we first discuss the admissible error of weighted mean temperature to enable the accuracy of the conversion better than 1 mm,then summarize the performance of some of the existing methods. An empirical formula is established that satisfies the real_time requirement in GPS meteorology using Sequential Regression Analysis method.It is shown that this real_time formula as compared with other empirical methods is more accurate for local applications. | Liu Yanxiong Chen Yongqi Liu Jingnan | 2001 | Geo-Spatial Information Science2001,4,1: | 3 |
| 18 | On the Generation Algorithm of VRS Virtual Observations显示文摘In the past few years, network RTK positioning technology, especially the VRS technology, has been widely used in some parts of China and in many countries around the world. The principle of the VRS technology is discussed with corresponding formula deduction, and detailed descriptions and applications of VRS corrections and virtual observations generation algorithm are given. | WEI Erhu CHAI Hua LIU Jingnan AN Zhiguo | 2007 | Geo-Spatial Information Science2007,10,2: | 3 |
| 19 | Observable-specific phase biases of Wuhan multi-GNSS experiment analysis center’s rapid satellite products显示文摘Precise Point Positioning(PPP)with Ambiguity Resolution(AR)is an important high-precision positioning technique that is gaining popularity in geodetic and geophysical applications.The implementation of PPP-AR requires precise products such as orbits,clocks,code,and phase biases.As one of the analysis centers of the International Global Navigation Satellite System(GNSS)Service(IGS),the Wuhan University Multi-GNSS experiment(WUM)Analysis Center(AC)has provided multi-GNSS Observable-Specific Bias(OSB)products with the associated orbit and clock products.In this article,we first introduce the models and generation strategies of WUM rapid phase clock/bias products and orbit-related products(with a latency of less than 16 h).Then,we assess the performance of these products by comparing them with those of other ACs and by testing the PPP-AR positioning precision,using data from Day of the Year(DOY)047 to DOY 078 in 2022.It is found that the peak-to-peak value of phase OSBs is within 2 ns,and their fluctuations are caused by the clock day boundary discontinuities.The associated Global Positioning System(GPS)orbits have the best consistency with European Space Agency(ESA)products,and those of other systems rank in the medium place.GLObal NAvigation Satellite System(GLONASS)clocks show slightly inconsistency with other ACs’due to the antenna thrust power adopted,while the phase clocks of other GNSSs show no distortion compared with legacy clocks.With well-estimated phase products for Precise Orbit Determination(POD),the intrinsic precision is improved by 14%,17%,and 24%for GPS,Galileo navigation satellite system(Galileo),and BeiDou-3 Navigation Satellite System(BDS-3),respectively.The root mean square of PPP-AR using our products in static mode with respect to IGS weekly solutions can reach 0.16 cm,0.16 cm,and 0.44 cm in the east,north,and up directions,respectively.The multi-GNSS wide-lane ambiguity fixing rates are all above 90%,while the narrow-lane fixing rates above 80%.In conclusion,the phase OSB products at WUM have good precision and performance,which will benefit multi-GNSS PPP-AR and POD. | Jianghui Geng Qiyuan Zhang Guangcai Li Jingnan Liu Donglie Liu | 2022 | Satellite Navigation2022,3,3: | 3 |
| 20 | The atlas of cytoophidia in Drosophila larvae显示文摘In 2010,cytidine 50-triphosphate synthase(CTPS)was reported to form the filamentous or serpentine structure in Drosophila,which we termed the cytoophidium.In the last decade,CTPS filaments/cytoophidia have been found in bacteria,budding yeast,human cells,mice,fission yeast,plants,and archaea,indicating that this mechanism is highly conserved in evolution.In addition to CTPS,other metabolic enzymes have been identified to have the characteristics of forming cytoophidia or similar advanced structures,demonstrating that this is a basic strategy of cells.Nevertheless,our understanding of the physiological function of the cytoophidium remains incomplete and elusive.Here,we took the larva of Drosophila melanogaster as a model to systematically describe the localization and distribution of cytoophidia in different tissues during larval development.We found that the distribution pattern of CTPS cytoophidia is dynamic and heterogenic in larval tissues.Our study provides a road map for further understanding of the function and regulatory mechanism of cytoophidia. | Yuanbing Zhang Jingnan Liu Ji-Long Liu | 2020 | Journal of Genetics and Genomics2020,47,6: | 2 |