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Segment routing for traffic engineering and effective recovery in low-earth orbit satellite constellations

Digital Communications and Networks 2024年第3期10卷 706-715页

作者： Shengyu Zhang xiaoqian li Kwan Lawrence Yeung Department of Electrical and Electronic Engineering The University of Hong KongHKSARChina National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengduSichuan611731China

Low-Earth Orbit Satellite Constellations(LEO-SCs)provide global,high-speed,and low latency Internet access services,which bridges the digital divide in the remote *** inter-satellite links are not supported in initial deployment(*** Starlink),the communication between satellites is based on ground stations with radio frequency *** to the rapid movement of satellites,this hybrid topology of LEO-SCs and ground stations is time-varying,which imposes a major challenge to uninterrupted service provisioning and network *** this paper,we focus on solving two notable problems in such a ground station-assisted LEO-SC topology,i.e.,traffic engineering and fast reroute,to guarantee that the packets are forwarded in a balanced and uninterrupted ***,we employ segment routing to support the arbitrary path routing in *** solve the traffic engineering problem,we proposed two source routings with traffic splitting algorithms,Delay-Bounded Traffic Splitting(DBTS)and DBTS+,where DBTS equally splits a flow and DBTS+favors shorter ***-lation results show that DBTS+can achieve about 30%lower maximum satellite load at the cost of about 10%more *** guarantee the fast recovery of failures,two fast reroute mechanisms,Loop-Free Alternate(LFA)and LFA+,are studied,where LFA pre-computes an alternate next-hop as a backup while LFA+finds a 2-segment backup *** show that LFA+can increase the percentage of protection coverage by about 15%.

关键词： Fast reroute Low-earth orbit satellite constellation Segment routing Traffic engineering Traffic splitting

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Function-reversible facets enabling SrTiO_(3)nanocrystals for improved photocatalytic hydrogen evolution

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Frontiers in Energy 2024年第1期18卷 101-109页

作者： Bin WANG Bei AN xiaoqian li Shaohua SHEN School of Physics Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter(Ministry of Education)Key Laboratory of Shaanxi for Advanced Materials and Mesoscopic PhysicsXi’an Jiaotong UniversityXi’an 710049China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

It has been widely reported that,for faceted nanocrystals,the two adjacent facets with different band levels contribute to promoted charge separation,and provide active sites for photocatalytic reduction and oxidation reaction,*** such cases,only one family of facets can be used for photocatalytic hydrogen ***,by using SrTiO_(3)nanocrystals enclosed by{023}and{001}facets as a model photocatalyst,this paper proposed a strategy to achieve the full-facets-utilization of the nanocrystals for photocatalytic hydrogen via chemically depositing Pt nanoparticles on all *** photo-deposition experiment of CdS provided direct evidence to demonstrate that the{023}facets which were responsible for photooxidation reaction can be function-reversed for photocatalytic hydrogen evolution after depositing Pt nanoparticles,together with the{001}***,the full-facets-utilization led to a much-improved activity for photocatalytic hydrogen,in contrast to those SrTiO_(3)nanocrystals with only{001}facets deposited by Pt nanoparticles via a photo-deposition method.

关键词： SrTiO_(3)nanocrystals crystal facets photocatalysis hydrogen evolution

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Stackelberg Game Approach to Mixed H2/H∞ Problem for Continuous-Time System

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Journal of Systems Science & Complexity 2019年第5期32卷 1324-1339页

作者： li xiaoqian WANG Wei XU Juanjuan ZHANG Huanshui School of Control Science and Engineering Shandong University

This paper studies the mixed H2/H∞ control for continuous-time linear dynamic *** applying Stackelberg game approach, the control input is treated as the leader and the disturbance is treated as the follower, respectively. Under standard assumptions and maximum principle, a necessary and sufficient existence condition which is based on three decoupled Riccati equations is *** expression of controllers and solutions to forward backward differential equations(FBDES)are obtained by homogeneous analysis of variables. A numerical example is finally given to verify the efficiency of the proposed approach.

关键词： Continuous-time case mixed H2/H∞ control open-loop controller Stackelberg game approach

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DC Traction Power Supply System Based on Modular Multilevel Converter Suitable for Energy Feeding and De-icing

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 649-659页

作者： lingxi Hou Shuqing Zhang Yingdong Wei xiaoqian li Qirong Jiang Mingrui li Weirui li Department of Electrical Engineering Tsinghua UniversityBeijing 100084China

A novel DC traction power supply system suitable for energy feeding and de-icing is proposed in this paper for an urban rail transit catenary on the basis of the full bridge submodule (FBSM) modular multilevel converter (MMC). The FBSM-MMC is a novel type of voltage source converter (VSC) and can directly control the output DC voltage and conduct bipolar currents, thus flexibly controlling the power flow of the urban rail transit catenary. The proposed topology can overcome the inherent disadvantages of the output voltage drop in the diode rectifier units, increase the power supply distance and reduce the number of traction substations. The flexible DC technology can coordinate multiple FBSM-MMCs in a wide area and jointly complete the bidirectional control of catenary power flow during the operation of the electric locomotive, so as to realize the local consumption and optimal utilization of the recovered braking energy of the train. In addition, the FBSM-MMCs can also adjust the output current when the locomotive is out of service to prevent the catenary from icing in winter. The working modes of the proposed topology are illustrated in detail and the control strategy is specially designed for normal locomotive operations and catenary de-icing. Simulation cases conducted by PSCAD/EMTDC validate the proposed topology and its control strategy.

关键词： DC traction power supply system de-icing for catenary energy feeding modular multilevel converter based on full-bridge submodules(FBSM-MMC) urban rail transit

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A Stackelberg strategy for continuous-time mixed H2/H∞ control problem with time delay

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Control Theory and Technology 2018年第3期16卷 191-202页

作者： xiaoqian li Wei WANG Juanjuan XU Huanshui ZHANG School of Control Science and Engineering Shandong University Jinan Shandong 250061 China

This paper is concerned with the mixed H2/H∞ control with linear continuous time system and time delay. To deal with this, we presents a Stackelberg strategy by treating the control input and the disturbance as leader and follower, respectively. The leader＇s control strategy minimizes the cost function which is in H2 norm and the follower＇s control strategy maximizes the cost function which is in H∞ norm. The main technique of this paper is deal with the noncausal relationship of the variables caused by time delay in the control input by introducing two costates to capture the future information and one state to capture the past information. Through theory analyzing, the Stackelberg strategy exists uniquely. Moreover, with the assistance of the extended state space expression, the explicit expression of the strategy is obtained.

关键词： Mixed H2/H∞ control continuous-time system Stackelberg strategy time delay

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Development and deployment of an instrument for measurement of atmospheric peroxy radical by chemical amplification

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Science China Earth Sciences 2009年第3期52卷 333-340页

作者： li xiaoqian QI Bin ZENG liMin TANG XiaoYan State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China School of Chemistry and Material Sciences Shaanxi Normal UniversityXi’an 710062China

An instrument for measurement of peroxy radical by chemical amplification (PERCA) has been devel- oped at Peking University (PKU) and deployed in several field campaigns. PKU PERCA measures per- oxy radical via amplification of NO2 by peroxy radical in the presence of NO and CO through a chain reaction. The amount of amplified NO2 is detected by a NO2-luminal chemiluminescence detector. The chain length (CL) of 75±20 (1σ ) was determined routinely during field campaigns using a HO2 source from photolysis of water vapor at 185 nm in air. The detection limit for peroxy radical measurement was (1-5)×10?12 (volume ratio) with integration time of 1 min, mainly relying on the variation of the ambient O3 and NO2. The systematic uncertainty in the measurement of peroxy radical was estimated to be ±60%. The effect of water vapor on PKU PERCA was observed and determined in the laboratory. The meas- urements of peroxy radical during the Program of Regional Integrated Experiments of Air Quality over Pearl River Delta 2006 (PRIDE-PRD2006) campaign are presented to show the performance of the PERCA instrument and the behavior of the observed peroxy radical is discussed briefly.

关键词： peroxy radical PERCA measurement atmosphere

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Transforming growth factor β1 is a differentially expressed candidate protein of congestive heart failure with Qi-deficiency-blood-stasis syndrome

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Journal of Traditional Chinese Medicine 2020年第2期40卷 311-316页

作者： li xiaoqian Huang Pinxian Wang Shijun Cao Xuebin He Jiancheng Research Centre on Application of Classical Prescriptions Basic Medical CollegeShanghai University of Traditional Chinese MedicineShanghai 201230China Department of Cardiology Shanghai Institute of Cardiovascular DiseasesZhongshan HospitalFudan UniversityShanghai 200032China Department of Cardiology The PLA 252 HospitalBaoding 71000China

OBJECTIVE: To investigate the role of tongue coating fluid protein in regulation of congestive heart failure(CHF) in Qi-deficiency-blood-stasis ***: We studied patients with CHF(3 patients with Qi-deficiency-blood-stasis syndrome and 3 without Qi-deficiency-blood-stasis syndrome) to investigate differentially expressed proteins. We also included a control group. A biotin label-based antibody array was used for testing tongue coating fluid samples from patients. Net-work analysis of these differentially expressed proteins was conducted using the STRING database,which can predict the relations between differentially expressed proteins and CHF with Qi-deficiency-blood-stasis ***: A total of seven differentially expressed proteins were identified, and among these, transforming growth factor β1(TGF-β1) gets a particular attention for us has drawn specific *** analysis showed a homologous relationship of TGF-β1 with bone morphogenetic protein15, which is associated with myocardial ***: Occurrence and development of CHF may result from certain DE-proteins and associated signaling pathways. TGF-β1 protein may be a candidate marker for assessing the risk of CHF in Qideficiency-blood-stasis syndrome.

关键词： Congestive heart failure Qi-deficiency blood-stasis Transforming growth factorβ1 Bone morphogenetic protein 15 Differentially expressed protein

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A generalizable strategy based on the rule of“like dissolves like”to construct porous liquids with low viscosity for CO_(2)capture

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Nano Research 2023年第7期16卷 10369-10380页

作者： Yangyang Xin Hailong Ning Dechao Wang(✉) xiaoqian li Wendi Fan xiaoqian Ju Hongni Wang Yichi Zhang Zhiyuan Yang Dongdong Yao Yaping Zheng School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi’an 710129China School of Chemistry and Chemical Engineering Nanjing UniversityNanjing 210023China College of Chemistry and Chemical Engineering Xi’an University of Science and TechnologyXi’an 710054China Key Laboratory of Coal Resources Exploration and Comprehensive Utilization Ministry of Natural ResourcesXi’an 710021China

Porous liquids(PLs),an emerging porous material with permanent cavities,have attracted extensive attention in recent ***,the current construction methods are complicated and resulting PLs possess high viscosity values,which cannot meet the requirements of practical industrial ***,we demonstrate a generalizable and simple strategy to prepare type III PLs with low viscosity based on the rule of“like dissolves like”.Specifically,the monoglycidyl ether terminated polydimethylsiloxane(denoted by E-PDMS)is attached to the surface of Universitetet i Oslo(UiO)-66-NH_(2)via covalent linkage,constructing the pore generator(UiO-66-NH_(2)-E-PDMS,denoted by P-UiO-66).Then,P-UiO-66 is dispersed into different types and amounts of sterically hindered solvents(PDMS400 or PDMS6000),obtaining a series of type III PLs(denoted by P-UiO-66-PLs)with permanent cavities and low *** gas sorption-desorption test shows that P-UiO-66-PLs have an enormous potential for CO_(2)/N_(2) selective ***,the porosity of P-UiO-66-PLs and the CO_(2)sorption mechanism are demonstrated by molecular ***,the generality of the synthesis strategy is confirmed by the successful construction of PLs using two other amino-metal-organic frameworks(MOFs)(MIL-53(Al)-NH_(2)and MIL-88B(Fe)-NH_(2)).Importantly,it’s worth noting that the strategy based on the rule of“like dissolves like”sheds light on the preparation of other types of PLs for task-specific applications.

关键词： porous liquids like dissolves like CO_(2)capture low viscosity

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Photolabile Protecting Group-Mediated Synthesis of 2-Deoxy-Glycosides

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Chinese Journal of Chemistry 2021年第12期39卷 3309-3314页

作者： xiaoqian li Zhi Ma Rongkun liu Mattan Hurevich You Yang Shanghai Key Laboratory of New Drug Design Engineering Research Center of Pharmaceutical Process ChemistryMinistry of EducationSchool of PharmacyEast China University of Science and Technology130 Meilong RoadShanghai 200237China Institute of Chemistry Safra CampusGivat RamHebrew University of Jerusalem91904Israel

A green and efficient photolabile protecting group(PPG)-mediated glycosidation approach for the synthesis of 2-deoxy-glycosides is *** employing ortho-nitrobenzyl carbonate(oNBC)as PPG,N,N-dimethylformamide(DMF)-modulated SPhosAuNTf_(2)-promoted glycosidation with per-oNBC-protected 2-deoxy-glycosyl ynenoates affords the 2-deoxy-glycosides with moderate to excellentα-selectivities presumably depending on the reactivities of the acceptor *** on the PPG-mediated glycosidation approach,oligosaccharides with three to six oNBC groups are effectively *** multiple oNBC groups in the 2-deoxy-glycosides are completely cleaved by irradiation at 365 nm,resulting in the desired 2-deoxy-glycosides in an efficient manner without affecting the common alkyne,alkene,azide functional groups and the traditional protecting groups on the aglycones.

关键词： Glycosides Glycosylation Protecting groups Gold Glycosyl ynenoates

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A Novel Location Management Scheme based on DNS in Proxy Mobile IPv6

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China Communications 2010年第3期7卷 43-52页

作者： Qiu Feng li xiaoqian Su Wei Zhang Hongke National Engineering Laboratory for Next Generation Internet Interconnection Devices Beijing Jiaotong University Beijing 100044 P R. China

Proxy Mobile IPv6 (PMIPv6) is designed to provide a network-based localized mobility management protocol, but it does not handle the global mobility of hosts. In this paper, we propose a location management scheme based on Domain Name System (DNS) for PMIPv6 which can support global mobility by using DNS as a location manager. In addition, to support large numbers of mobile terminals and enhance network scalability a paging extension scheme is introduced to PMIPv6. To evaluate the proposed location management scheme, we establish an analytical model, formulate the location update cost and the paging cost, and analyze the influence of the different factors on the total signaling cost. The performance results show that our proposed scheme outperforms the basic PMIPv6 under various parameters in terms of reducing the signaling overhead and the proposed scheme reduces signaling overhead compared to the basic PMIPv6.

关键词： component Proxy Mobile IPv6 location manager mobility management paging

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