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Iterative identification and control design with optimal excitation signals based on v-gap

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Science in China(Series F) 2009年第7期52卷 1120-1128页

作者： DOU liqian ZONG Qun zhao ZhanShan JI YueHui School of Electrical and Automation Engineering Tianjin University Tianjin 300072 China

An iterative identification and control design method based on v-gap is given to ensure the stability of closed-loop system and control performance improvement. The whole iterative procedure includes three parts： the optimal excitation signals design, the uncertainty model set identification and the stable controller design. Firstly the worst case v-gap is used as the criterion of the optimal excitation signals design, and the design is performed via the power spectrum optimization. And then, an uncertainty model set is attained by system identification on the basis of the measure signals. The controller is designed to ensure the stability of closed-loop system and the closed-loop performance improvement. Simulation result shows that the proposed method has good convergence and closed-loop control performance.

关键词： excitation signals design control design iterative identification v-gap

Numerical simulation of gas-solid flow with two fluid model in a spouted-fluid bed

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Particuology 2014年第3期12卷 109-116页

作者： Shuyan Wang liqian zhao Chunsheng Wang Yinsong Liu Jinsen Gao Yang Liu Qinglin Cheng School of Petroleum Engineering Northeast Petroleum University State Key Laboratory of Heavy Oil Processing China University of Petroleum

The flow characteristics in a spouted-fluid bed differ from those in spouted or fluidized beds because of the injection of the spouting gas and the introduction of a fluidizing gas. The flow behavior of gas-solid phases was predicted using the Eulerian-Eulerian two-fluid model （TFM） approach with kinetic theory for granular flow to obtain the flow patterns in spouted-fluid beds. The gas flux and gas incident angle have a significant influence on the porosity and particle concentration in gas-solid spouted-fluid beds. The fluidizing gas flux affects the flow behavior of particles in the fountain. In the spouted-fluid bed, the solids volume fraction is low in the spout and high in the annulus. However, the solids volume fraction is reduced near the wall.

关键词： Spouted-fluid bed Two fluid modeling CFD Fluidization

Inter-satellite link augmented BeiDou-3 orbit determination for precise point positioning

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Chinese Journal of Aeronautics 2022年第4期35卷 332-343页

作者： liqian zhao Xiaogong HU Chengpan TANG Shanshi ZHOU Yueling CAO Qianxin WANG Ranran SU Space Star Technology Co. Ltd.Beijing 100095China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou 221116China Beijing Satellite Navigation Center Beijing 100094China

Precise Point Positioning(PPP) requires precise products, including high-accuracy satellite orbit and clock parameters. It is impossible to obtain an orbit solution that is sufficiently accurate for PPP services with a regional tracking network;therefore, satellite orbits are usually estimated by a global tracking network with a large number of ground stations. However, it is expensive to build globally distributed stations. Fortunately, BeiDou-3 satellites carry an InterSatellite Link(ISL) payload, which can track the whole arc of the BeiDou-3 satellites and enhance the orbit determination accuracy with regional ground stations. In this contribution, a novel orbit determination strategy for BeiDou-3 PPP is proposed, in which the BeiDou-3 satellite orbits are enhanced by the ISL. First, the generation of precise satellite products is demonstrated in *** addition, the products are assessed by Satellite Laser Ranging(SLR) residuals and overlap comparisons. Moreover, the products are used for receivers in China's Mainland to carry out the static and kinematic modes to research the PPP performance of Bei Dou-3’s 3IGSO/24MEO *** SLR validations of the satellite orbits demonstrate an accuracy better than 0.1 m in the radial component, and the orbit overlap comparisons show accuracies of 0.016 m in the radial component,0.088 m in the along-track component and 0.087 m in the cross-track component. The Standard Deviation(STD) in the differences in overlapping arcs for the estimated satellite clocks is approximately 0.10 ns. The static PPP results demonstrate that the error in both the horizontal and vertical components is smaller than 10 cm after 30 minutes of convergence. After 24 hours of convergence,the errors are 0.70 cm, 0.63 cm and 1.99 cm for the north, east and up components, *** kinematic PPP experiment illustrates that the Root Mean Square(RMS) position errors in the north, east and up components are approximately 3.23 cm, 5.27 cm a

关键词： BeiDou-3 Clock offsets Convergence Inter-satellite link Precise Point Positioning Regional ground stations Satellite orbits

Glioma cell membrane camouflaged cinobufotalin delivery system for combinatorial orthotopic glioblastoma therapy

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Nano Research 2023年第8期16卷 11164-11175页

作者： Zibin Song liqian zhao Weiyi Fang Siyun Guo Anqi Xu Zhengming Zhan Yonghua Cai ShuaiShuai Xue Peng Chai Qiuhua Jiang Peng zhao Ye Song Department of Neurosurgery Southern Medical University Nanfang HospitalGuangzhou 510515China Institute of Brain Diseases Nanfang Hospital of Southern Medical UniversityGuangzhou 510515China Cancer Center Integrated Hospital of Traditional Chinese MedicineSouthern Medical UniversityGuangzhou 510515China NMPA Key Laboratory for Research and Evaluation of Drug Metabolism Guangdong Provincial Key Laboratory of Cardiac Function and Microcirculation GuangdongProvincial Key Laboratory of New Drug ScreeningSchool of Pharmaceutical SciencesSouthern Medical UniversityGuangzhou 510515China Department of Neurosurgery Ganzhou People's HospitalGanzhou 341000China

Glioblastoma(GBM)belongs to the deadliest primary malignancies with high mortality rate and poor *** the past decades,less progress has been made to treat GBM,owing largely to the lack of effective chemotherapeutics and poor drug accumulation in the glioma *** order to address this issue,we present an efficient biomimetic nanocomposite(Cu_(2−x)Se-CB@MEM,CCM),consisting of Cu_(2−x)Se nanoparticle core modified by cinobufotalin(CB),a toad venom extract,which is camouflaged with glioma cell Ln229 *** is demonstrated that CB can decrease the protein activity of inosine monophosphate dehydrogenase 1(IMPDH1),a key target correlated with prognosis,through intermolecular hydrogen bonding with amino acid residues ARG-105 and *** glioma cell membrane-camouflage endows the CCM with blood-brain barrier penetration and homology tumor-targeted *** optimized cinobufotalin based chemotherapy combining with the near-infrared-II(NIR-II)irradiation shows outstanding inhibition effect to glioma cells,by blocking cell cycle and inducing *** vivo mice bearing orthotopic Ln229 GBM treated with CCM+NIR-II(CCM+L)have significantly suppressed tumor growth and extended survival,without side *** glioma cell membrane camouflaged nanocomposite of Cu_(2−x)Se and cinobufotalin with its significant anti-glioma property and well biosafety will provide novel alternatives for clinical treatment of GBM.

关键词： glioblastoma cinobufotalin biomimetics photothermal therapy blood-brain barrier

Reasonable grazing may balance the conflict between grassland utilization and soil conservation in the semi-arid hilly areas, China

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Journal of Arid Land 2024年第8期16卷 1130-1146页

作者： SUN Hui zhao Yunge GAO liqian XU Mingxiang College of Forestry Northwest A&F UniversityYangling 712100China College of Soil and Water Conservation Science and Engineering Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China

Soil erosion caused by unsustainable grazing is a major driver of grassland ecosystem degradation in many semi-arid hilly areas in ***,grazing exclusion is considered as an effective method for solving this issue in such ***,some ecological and economic problems,such as slow grassland rejuvenation and limited economic conditions,have become obstacles for the sustainable utilization of grassland ***,we hypothesized that the conflict between grassland use and soil conservation may be balanced by a reasonable grazing *** this study,a two-year grazing fence experiment with five grazing intensity gradients was conducted in a typical grassland of the Loess Plateau in China to evaluate the responses of vegetation characteristics and soil and water losses to grazing *** five grazing intensity gradients were 2.2,3.0,4.2,6.7,and 16.7 goats/hm2,which were represented by G1-G5,respectively,and no grazing was used as *** results showed that a reasonable grazing intensity was conducive to the sustainable utilization of grassland *** biomass under G1-G4 grazing intensity significantly increased by 51.9%,42.1%,36.9%,and 36.7%,respectively,compared with *** addition,vegetation coverage increased by 19.6%under G1 grazing *** diversity showed a single peak trend with increasing grazing *** Shannon-Wiener diversity index under G1-G4 grazing intensities significantly increased by 22.8%,22.5%,13.3%,and 8.3%,respectively,compared with ***,grazing increased the risk of soil *** with control,runoff yields under G1-G5 grazing intensities increased by 1.4,2.6,2.8,4.3,and 3.9 times,respectively,and sediment yields under G1-G5 grazing intensities were 3.0,13.0,20.8,34.3,and 37.7 times greater,respectively,than those under *** result was mainly attributed to a visible decrease in litter biomass after grazing,which decreased by 50.5%,72.6%,79.0%,80.0%

关键词： fence-controlled grazing rehabilitated grassland vegetation community characteristics soil erosion sediment biocrusts Loess Plateau

Pseudorange Bias Correction for BDSBAS Single Frequency Service

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Pseudorange Bias Correction for BDSBAS Single Frequency Serv...

Precise Orbit and Clock Offset Determination of LEO Navigation Satellites Based on Multi-constellation and Multi-frequency Spaceborne GNSS Data

第十三届中国卫星导航年会

作者： liqian zhao Biao Jin Qijia Dong Zixiao Li Ningning Liu Space Star Technology Co. Ltd.

BDSBAS broadcasts SBAS corrections and integrity information via BDSBAS-B1 C signals of BeiDou-3 GEO satellites to improve the accuracy and integrity for GPS L1 CA single-frequency users in BDSBAS service area. However, if the GPS receiver type and technical status of BDSBAS reference station is quite different from the receiver of GPS ground operational control system and the BDSBAS receivers do not fully refer to the receivers of GPS ground operational control system to adjust the correlator spacing and front-end bandwidth, there will be inevitable relative pseudorange bias between the BDSBAS receivers and GPS ground operational control system receivers. Pseudorange bias is an important factor restricting the performance of BDSBAS singlefrequency service. This contribution analyzes the impact of GPS satellite pseudorange bias on the accuracy of BDSBAS single-frequency service, and then proposes a pseudorange bias correction method based on the Timing Group Delay（TGD） parameters, which can eliminate the impact of pseudorange bias on the GPS L1 CA SBAS positioning accuracy and improve the single-frequency service performance of BDSBAS. Six stations in the BDSBAS service area are used to carry out GPS L1 CA SBAS positioning experiment, the experiment results reveal that the average 95% positioning accuracy has a significant improvement after using the mentioned method to correct the pseudorange bias. The positioning errors are reduced from 1.70 m to 1.38 m and from 2.83 m to 2.29 m in the horizontal and vertical directions, respectively.

关键词： BDSBAS Reference Station Pseudorange Bias Timing Group Delay Service Performance

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Precise Orbit and Clock Offset Determination of LEO Navigati...

兰州石化化肥厂生产管理信息系统的实施与应用

第十四届中国卫星导航年会

作者： Junjun Yuan Ertao Liang liqian zhao Kai Li Chengpan Tang Shanshi Zhou Xiaogong Hu Shanghai Astronomical Observatory Chinese Academy of Sciences Space Star Technology Co. Ltd. Shanghai Key Laboratory of Space Navigation and Positioning Techniques Shanghai Astronomical Observatory Chinese Academy of Sciences

With massive low earth orbit(LEO) satellites, LEO navigation enhancement system is important to improve the service performance of GNSS system. The high precision orbit and clock offset calculation of LEO satellites is one key to establish the stable and reliable space-time reference. Based on GPS/BDS/GALILEO data measured by LEO navigation satellites, this paper determines the precise LEO orbit and clock offset, and evaluates the precision of LEO orbit and clock offset solution. The orbit determination accuracy using GPS(L1/L2), GPS(L1/L5), BDS(B1C/B2a), and GALILEO(E1/E5a)combination is 2.42, 2.93, 2.67, and 2.87 cm, respectively. The clock offset solution accuracy using the above four combination is 0.167, 0.194, 0.186, and0.180 ns, respectively. These results can provide high-quality product for navigation enhancement system services.

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计算机光盘软件与应用 2010年第4期13卷 5-6,9页

作者：赵莉谦兰州石化公司通信网络中心技术发展部兰州730060

在现有的兰州石化化肥厂各装置实时数据库的基础上，通过专用数据接口程序，对需要的位号进行组态，定时把实时数据库中的数据写入Sybase关系数据库并进行整合，作为基础数据。在此基础数据上开发了化肥厂的物料平衡系统和能源计量系统... 详细信息

在现有的兰州石化化肥厂各装置实时数据库的基础上，通过专用数据接口程序，对需要的位号进行组态，定时把实时数据库中的数据写入Sybase关系数据库并进行整合，作为基础数据。在此基础数据上开发了化肥厂的物料平衡系统和能源计量系统，并且采用了PHP技术JSP技术生成动态网页方便查询生产信息。

关键词：实时数据库生产资源管理 JSP

BDS监测站坐标确定及对定轨精度的影响分析

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武汉大学学报（信息科学版） 2020年第10期45卷 1501-1507页

作者：赵立谦胡小工周善石唐成盼杨宇飞中国科学院上海天文台上海200030 中国科学院大学北京100049 信息工程大学河南郑州450001

对北斗监测站(框架点)坐标的计算方法进行探讨,提出精密单点定位和联合MGEX数据网解两种处理方案确定北斗地面监测网各站在国际地球参考架下的精密坐标。利用北斗观测数据对两种方案进行验证,特别分析了地面监测网各站坐标精化对北斗导... 详细信息

对北斗监测站(框架点)坐标的计算方法进行探讨,提出精密单点定位和联合MGEX数据网解两种处理方案确定北斗地面监测网各站在国际地球参考架下的精密坐标。利用北斗观测数据对两种方案进行验证,特别分析了地面监测网各站坐标精化对北斗导航卫星区域网定轨精度的提升。初步计算结果表明:精密单点定位处理方案得到的各地面监测站坐标水平和高程的重复性分别为2.3 cm和3.4 cm,联合MGEX北斗数据网解处理方案得到的坐标水平和高程重复性分别为0.8 cm和2.2 cm。利用网解方案对监测站坐标进行更新后:IGSO(inclined geosynchronous orbit)卫星3D重叠弧段精度平均提升15.4%,MEO(medium earth orbit)卫星3D重叠弧段精度平均提升25.8%;北斗二号卫星平均激光检核残差由0.39 m降至0.24 m,平均精度提升38%;北斗三号卫星平均激光检核残差由0.25 m降至0.18 m,平均精度提升28%。

关键词：北斗监测站精密单点定位网解区域网定轨精度重复性