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BDS satellite clock offset prediction based on a semiparametric adjustment model considering model errors

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Satellite Navigation 2020年第1期1卷 113-125页

作者： xiong Yan Wentao Li Yufeng Yang xiong pan School of Information and Engineering China University of GeosciencesNo.388Lu Mill RoadHongshan DistrictWuhanChina Chihiro Location Network Co. Ltd.Bay Valley Science and Technology ParkNo.38Lane 1688Guoquan North RoadYangpu DistrictShanghaiChina

In view of the influence of model errors in conventional BeiDou prediction models for clock offsets,a semiparametric adjustment model for BeiDou Navigation Satellite System(BDS)clock offset prediction that considers model errors is proposed in this ***,the model errors of the conventional BeiDou clock offset prediction model are ***,the relationship among the polynomial model,polynomial model with additional periodic term correction,and its periodic correction terms is explored in ***,considering the model errors,combined with the physical relationship between phase,frequency,frequency drift,and its period in the clock sequence,the conventional clock offset prediction model is *** kernel estimation and comprehensive least squares,the corresponding parameter solutions of the prediction model and the estimation of its model error are derived,and the dynamic error correction of the clock sequence model is ***,the BDS satellite precision clock data provided by the IGS Center of Wuhan University with a sampling interval of 5 min are used to compare the proposed prediction method with commonly used *** results show that the proposed prediction method can better correct the model errors of BDS satellite clock offsets,and it can effectively overcome the inaccuracies of clock offset *** average forecast accuracies of the BeiDou satellites at 6,12,and 24 h are 27.13%,37.71%,and 45.08%higher than those of the conventional BeiDou clock offset forecast models;the average model improvement rates are 16.92%,20.96%,and 28.48%,*** addition,the proposed method enhances the existing BDS satellite prediction method for clock offsets to a certain extent.

关键词： BDS Satellite clock offset Model errors Semiparametric adjustment model Clock offset forecast

Robust D-stability LMI conditions of matrix polytopes via affine parameter-dependent Lyapunov functions

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Journal of Systems Engineering and Electronics 2013年第6期24卷 984-991页

作者： pan xiong Feng Wang Xibin Cao Guangren Duan School of Astronautics Harbin Institute of Technology National and Local United Research Center of Small Satellite Technology

The problem of the robust D-stability analysis for linear systems with parametric uncertainties is addressed. For matrix polytopes, new conditions via the affine parameter-dependent Lyapunov function of uncertain systems are developed with the benefit of the scalar multi-convex function. To be convenient for applications, such conditions are simplified into new linear matrix inequality （LMI） conditions, which can be solved by the powerful LMI toolbox. Numerical examples are provided to indicate that this new approach is less conservative than previous results for Hurwitz stability, Schur stability and D-stability of uncertain systems under certain circumstances.

关键词： linear uncertain system robust D-stability analysis linear matrix inequality (LMI) condition affine parameterdependent Lyapunov function matrix polytope.

Wind farm polymerization influences on security and economic operation in power system based on Copula function

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Journal of Modern Power Systems and Clean Energy 2015年第3期3卷 381-392页

作者： xiong pan Zhuo LIU Wenxia LIU Yanqing LI Postgraduate Workstation of Yunnan Power Gird Company Ltd.North China Electric Power UniversityKunming 650217China North China Electric Power University Baoding 071000China Grid Planning&Research Center Guizhou Power Grid CooporationCSGGuiyang 550002China

Wind speed dependences on different areas in a wind farm have influences on security and economic operation in power *** order to simulate the correlation of wind speed series between different positions,this paper applies Copula function and rank correlation matrix methods to measure the coherence of wind speed in a wind *** correlated wind sample space is *** to active power output characteristics of wind turbines,the polymerization model in a wind farm can be *** Carlo optimal power flow is applied to IEEE-30 and IEEE-300 bus systems based on the principle of energy saving *** study shows that the accuracy of outputs is improved,thus reducing the fluctuation ranges in unit generating costs and power flow in branches while considering wind speed *** approach provides a new method to improve the effectiveness of energy saving dispatching and system operation *** have been tested to be effective.

关键词： Copula function Wind farm polymerized model Rank correlation Optimal power flow

Hierarchical Porous Polymer Beads Prepared by Polymerization-induced Phase Separation and Emulsion-template in a Microfluidic Device

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Chinese Journal of Polymer Science 2014年第12期32卷 1646-1654页

作者： Wei-cai Wang Yan-xiong pan Kai Shi Chao Peng 姬相玲 State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

Porous polymer beads（PPBs） containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation（PIPS） and emulsion-template technique in a glass capillary microfluidic device（GCMD）. Fabrication procedure involved the preparation of water-in-oil emulsion by emulsifying aqueous solution into the monomer solution that contains porogen. The emulsion was added into the GCMD to fabricate the（water-in-oil）-in-water double emulsion droplets. The flow rate of the carrier continuous phase strongly influenced the formation mechanism and size of droplets. Formation mechanism transformed from dripping to jetting and size of droplets decreased from 550 μm to 250 μm with the increase in flow rate of the carrier continuous phase. The prepared droplets were initiated for polymerization by on-line UV-irradiation to form PPBs. The meso-macropores in these beads were generated by PIPS because of the presence of porogen and gigapores obtained from the emulsion-template. The pore morphology and pore size distribution of the PPBs were investigated extensively by scanning electron microscopy and mercury intrusion porosimetry（MIP）. New pore morphology was formed at the edge of the beads different from traditional theory because of different osmolarities between the water phase of the emulsion and the carrier continuous phase. The morphology and proportion of bimodal pore structure can be tuned by changing the kind and amount of porogen.

关键词： Porous polymer beads Hierarchical Polymerization-induced phase separation Emulsion-template Microfluidic device.

Study on the Catalytic Reforming Law of Solid-Phase Carbon and Nitrogen Sources Loaded with MnO_(2)at Low Temperatures in Tahe Heavy Oil

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China Petroleum Processing & Petrochemical Technology 2023年第4期25卷 52-60页

作者： Tan Dichen Ma Zhaofei Peng Gaoyao xiong pan Yan Xuemin College of Chemistry and Environmental Engineering Yangtze UniversityJingzhouHubei 434023PR China

MnO_(2)/Melem composites were synthesized with MnO_(2)nanoparticles loaded onto the Melem using the hydrothermal *** raw materials for C and N carriers,Melem was prepared from melamine roasted at 354℃,and KMnO_(4)as a raw material for Mn,MnO_(2)nanoparticles were prepared using the hydrothermal synthesis of KMnO_(4).Scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and a laser particle size analyzer were used for structural characterization,and the catalytic oxidation performance of the heavy oil was investigated at different reaction temperatures(100℃to 180℃)using MnO_(2)/Melem with an oxidant and donor protonic *** results showed that the synthesizedβ-MnO_(2)nanoparticles were successfully loaded onto the Melem surface;the oil samples before and after the reaction at different temperatures were subjected to SARA analysis using Fourier transform infrared(FT-IR),elemental analysis,gas chromatography-mass spectrometry(GC-MS)and viscosity tests,*** was determined that the hydrocarbons in the crude oil were converted to heavy mass by oxidation reactions with the oxidant mainly through a low-temperature oxidation process below 140℃in the heavy oil when the temperature exceeds 140℃,in addition to the oxidation reaction with the oxidant,a cleavage reaction in the carbon chain occurs to form hydrocarbon substances with lower molecular weights.

关键词： heavy oil catalyst low-temperature catalytic oxidation in situ reforming

Engineering of geometrical configurations in dual-atom catalysts for electrocatalytic applications

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Journal of Energy Chemistry 2024年第7期94卷 273-287页

作者： Tao Zhang Yifan Liu Liang Xue Jingwen Sun pan xiong Junwu Zhu Key Laboratory for Soft Chemistry and Functional Materials of Ministry Education School of Chemistry and Chemical EngineeringNanjing University of Science and TechnologyNanjing210094JiangsuChina

Geometrical configurations play a crucial role in dual-atom catalysts(DACs)for electrocatalytic *** progress has been made to design DACs electrocatalysts with various geometri-cal configurations,but in-depth understanding the relationship between geometrical configurations and metal-metal interaction mechanisms for designing targeted DACs is still *** this review,the recent progress in engineering of geometrical configurations of DACs is systematically *** on the polarity of geometrical configuration,DACs can be classified into two different types that are homonuclear and heteronuclear ***,with regard to the geometrical configurations of the active sites,homonuclear DACs are identified into adjacent and bridged configurations,and heteronuclear DACs can be classified into adjacent,bridged,and separated ***,metal-metal interactions in DACs with different geometrical configurations are ***,the applications of DACs in different electrocatalytic reactions are discussed,including the oxygen reduction reaction(ORR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and other ***,the future challenges and perspectives for advancements in DACs are *** review aims to provide inspiration for the design of highly effcient DACs towards energy relatedapplications.

关键词： Dual-atom catalysts Geometrical configurations Homonuclear Heteronuclear Electrocatalysis

Non-Communicable Diseases During the COVID-19 pandemic and Beyond

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Engineering 2021年第7期7卷 899-902页

作者： xiong-Fei pan Juan Yang Ying Wen Naishi Li Simiao Chen An pan Department of Epidemiology and Biostatistics School of Public HealthTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030China Division of Epidemiology Department of MedicineVanderbilt University Medical CenterNashvilleTN 37203USA The George Institute for Global Health University of New South WalesSydneyNSW 2042Australia Ministry of Education Key Laboratory of Public Health Safety School of Public HealthFudan UniversityShanghai 200032China Department of Communicable Diseases Control and Prevention Shenzhen Center for Disease Control and PreventionShenzhen 518055China National Health Commission Key Laboratory of Endocrinology Department of EndocrinologyPeking Union Medical College HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100730China Heidelberg Institute of Global Health Heidelberg Medical SchoolHeidelberg UniversityHeidelberg 69120Germany Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100730China

*** The coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has swept the globe as a pandemic[1].As of 1 April 2021,there were about 129.5 million confirmed cases of COVID-19,and 2.8 million deaths attributable to COVID-19[2].While some countries have suppressed COVID-19,most governments worldwide are still mobilizing available resources to contain the spread of SARS-CoV-2 in communities,facilitate COVID-19 treatments in hospitals,expand COVID-19 vaccination,and accelerate drug and vaccine development[3].

关键词： acute respiratory vaccine

Electrophoretic-deposited novel ternary silk fibroin/graphene oxide/hydroxyapatite nanocomposite coatings on titanium substrate for orthopedic applications

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Frontiers of Materials Science 2016年第3期10卷 270-280页

作者： Ming LI pan xiong Maosong MO Yan CHENG Yufeng ZHENG Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100190 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing 100049 China Center for Biomedical Materials and Tissue Engineering Academy for Advanced Interdisciplinary Studies Peking University Beijing 100871 China Department of Materials Science and Engineering College of Engineering Peking University Beijing 100871 China

The combination of graphene oxide （GO） with robust mechanical property, silk fibroin （SF） with fascinating biological effects and hydroxyapatite （HA） with superior osteogenic activity is a competitive approach to make novel coatings for orthopedic applications. Herein, the feasibility of depositing ternary SF/GO/HA nanocomposite coatings on Ti substrate was firstly verified by exploiting electrophoretic nanotechnology, with SF being used as both a charging additive and a dispersion agent. The surface morphology, microstructure and composition, in vitro hemocompatibility and in vitro cytocompatibility of the resulting coatings were investigated by SEM, Raman, FTIR spectra and biocompatibiUty tests. Results demonstrated that GO, HA and SF could be co-deposited with a uniform, smooth thin-film morphology. The hemolysis rate analysis and the platelet adhesion test indicated good blood compatibility of the coatings. The human osteosarcoma MG63 cells displayed well adhesion and proliferation behaviors on the prepared coatings, with enhanced ALP activities. The present study suggested that SFIGO/HA nanocomposite coatings could be a promising candidate for the surface functionalization of biomaterials, especially as orthopedic implant coating.

关键词： graphene oxide silk fibroin hydroxyapatite nano-biocomposite coatings electrodeposition

Double Emulsion Droplets as Microreactors for Synthesis of Magnetic Macroporous Polymer Beads

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Chinese Journal of Polymer Science 2014年第12期32卷 1639-1645页

作者： Wei-cai Wang Chao Peng Kai Shi Yan-xiong pan 张海山姬相玲 State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Colorectal and Anal Surgery China-Japan Union Hospital Jilin University

An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads（MMPBs）. Waterin-oil high internal phase emulsion（HIPE） is prepared by emulsifying aqueous iron ions solution in an oil phase containing monomers. The HIPE is introduced into a simple microfluidic device to fabricate monodisperse（water-in-oil）-in-water double emulsion droplets. The droplets serve as microreactors to synthesize Fe3O4 nanoparticles and are on-line polymerized to form MMPBs. The prepared MMPBs display uniform size, interconnected porous structure, superparamagnetic behavior and uniform distribution of Fe3O4 in polymer matrix. The MMPBs are characterized by scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, transmission electron microscopy（TEM）, vibrating sample magnetometry（VSM）. We believe that this method is a universal technique in preparing macroporous nanocomposite beads.

关键词： Double emulsion droplets Magnetic macroporous polymer beads Microreactor.