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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 695-706页

作者： Peiyuan sun Long Huo Xin Chen siyuan Liang the School of Electrical Engineering Xi'an Jiaotong University the School of Electrical Engineering and the Center of Nanomaterials for Renewable Energy State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University the Department of Computer Science and Engineering The Chinese University of Hong Kong

Rotor angle stability(RAS) prediction is critically essential for maintaining normal operation of the interconnected synchronous machines in power systems. The wide deployment of phasor measurement units(PMUs) promotes the development of data-driven methods for RAS prediction. This paper proposes a temporal and topological embedding deep neural network(TTEDNN) model to accurately and efficiently predict RAS by extracting the temporal and topological features from the PMU data. The grid-informed adjacency matrix incorporates the structural and electrical parameter information of the power grid. Both the small-signal RAS with disturbance under initial operating conditions and the transient RAS with short circuits on transmission lines are considered. Case studies of the IEEE 39-bus and IEEE 300-bus power systems are used to test the performance, scalability, and robustness against measurement uncertainties of the TTEDNN model. Results show that the TTEDNN model performs best among existing deep learning models. Furthermore, the superior transfer learning ability from small-signal RAS conditions to transient RAS conditions has been proved.

关键词： Power system stability Phasor measurement units Rotors Transient analysis Stability criteria Deep learning Circuit stability

Operational Characteristics of Loop Heat Pipe in Microgravity and Normal Gravity Environments

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Journal of Thermal Science 2024年第4期33卷 1394-1408页

作者： ZHONG siyuan XIE Rongjian LI Yunfei sun Xiaojin Shanghai Institution of Technology and Physics University of Chinese Academy of Sciences Shanghai Institute of Satellite Engineering

The loop heat pipe(LHP) is an advanced,efficient two-phase heat transfer unit,whose operational performance may be affected by microgravity conditions in contrast to ground-based applications.The performance of on-orbit temperature data and ground test of a copper-propylene LHP with a condenser temperature range of 243.15 K to 303.15 K were employed to compared and analyzed.The LHP has successfully started up for more than 193 times with a good heat transfer performance and a stable start-up stabilization on-orbit under a complex orbital heating environment for more than eight months.With a small heat load(10.0W),the average start-up time is 110.0 s while the start-up temperature ranges from 5.71 K-12.78 K.The start-up time at large temperature differences in the high temperature zone will be higher than the time required for start-up at smaller temperature differences in the low one.When the condenser temperature is 250.0 K,the stable temperature difference on orbit is 3.83 K,which is generally consistent in heat transfer compared to 2.20 K in the ground test.In this paper,we can conclude that the on-orbit flight data up to now can provide a reference to the design of subsequent LHP space applications.

关键词： Loop Heat Pipe (LHP) start up microgravity on-orbit experiment

Mechanism of capture section affecting an intake for atmosphere-breathing electric propulsion

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Chinese Journal of Aeronautics 2024年第1期37卷 51-63页

作者： siyuan ZHANG Jinyuan YANG Cheng LI Haolin LI Liwei ZHANG Liang DING Anbang sun State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi’an Jiaotong UniversityXi’an 710049China China Academy of Aerospace Science and Innovation Beijing 100049China

Atmosphere-Breathing Electric Propulsion(ABEP)can compensate for lost momentum of spacecraft operating in Very Low Earth Orbit(VLEO)which has been widely concerned due to its excellent commercial potential.It is a key technology to improve the capture efficiency of intakes,which collect and compress the atmosphere for ABEP.In this paper,the mechanism of the capture section affecting capture efficiency is investigated by Test Particle Monte Carlo(TPMC)simulations with 3D intake models.The inner surface smoothness and average collision number are determined to be key factors affecting capture efficiency,and a negative effect growth model is accordingly established.When the inner surface smoothness is less than 0.2,the highest capture efficiency and its corresponding average collision number interval are independent of the capture section’s geometry and its mesh size.When the inner surface smoothness is higher than 0.2,the capture efficiency will decrease by installing any capture section.Based on the present results,the manufacturing process and material selection are suggested to be prioritized during the intake geometry design in engineering projects.Then,the highest capture efficiency can be achieved by adjusting the length and mesh size of the capture section.

关键词： Atmosphere-breathing electric propulsion Capture efficiency Capture section Intake Test particle Monte Carlo Very low earth orbit

Non-bonding modulations between single atomic cerium and monodispersed selenium sites towards efficient oxygen reduction

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Nano Research 2024年第6期17卷 4753-4763页

作者： Leilei Yin Shuai Zhang Mingzi sun siyuan Wang Bolong Huang Yaping Du Tianjin Key Lab for Rare Earth Materials and Applications Center for Rare Earth and Inorganic Functional MaterialsHaihe Laboratory of Sustainable Chemical TransformationsSmart Sensing Interdisciplinary Science CenterSchool of Materials Science and EngineeringNational Institute for Advanced MaterialsNankai UniversityTianjin 300350China Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic UniversityHung HomKowloon 999077Hong KongChina Research Centre for Carbon-Strategic Catalysis The Hong Kong Polytechnic UniversityHung HomKowloon 999077Hong KongChina

Currently,dual atomic catalysts(DACs)with neighboring active sites for oxygen reduction reaction(ORR)still meet lots of challenges in the synthesis,especially the construction of atomic pairs of elements from different blocks of the periodic table.Herein,a“rare earth(Ce)-metalloid(Se)”non-bonding heteronuclear diatomic electrocatalyst has been constructed for ORR by rational coordination and carbon support defect engineering.Encouraging,the optimized Ce-Se diatomic catalysts(Ce-Se DAs/NC)displayed a half-wave potential of 0.886 V vs.reversible hydrogen electrode(RHE)and excellent stability,which surpass those of separate Ce or Se single atoms and most single/dual atomic catalysts ever reported.In addition,a primary zinc-air battery constructed using Ce-Se DAs/NC delivers a higher peak power density(209.2 mW·cm^(−2))and specific capacity(786.4 mAh·gZn^(−1))than state-of-the-art noble metal catalysts Pt/C.Theoretical calculations reveal that the Ce-Se DAs/NC has improved the electroactivity of the Ce-N_(4)region due to the electron transfer towards the nearby Se specific activity(SA)sites.Meanwhile,the more electron-rich Se sites promote the adsorptions of key intermediates,which results in the optimal performances of ORR on Ce-Se DAs/NC.This work provides new perspectives on electronic structure modulations via non-bonded long-range coordination micro-environment engineering in DACs for efficient electrocatalysis.

关键词： catalyst rare earth oxygen reduction reaction(ORR) metalloid non-bonding modulation

Novel phenanthrene/bibenzyl trimers from the tubers of Bletilla striata attenuate neuroinﬂammation via inhibition of NF-κB signaling pathway

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Chinese Journal of Natural Medicines 2024年第5期22卷 441-454页

作者： SHAO siyuan sun Mohan MA Xianjie JIANG Jianwei TIAN Jinying ZHANG Jianjun YE Fei LI Shuai State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

Five novel(9,10-dihydro)phenanthrene and bibenzyl trimers,as well as two previously identified biphenanthrenes and bibenzyls,were isolated from the tubers of Bletilla striata.Their structures were elucidated through comprehensive analyses of NMR and HRESIMS spectroscopic data.The absolute configurations of these compounds were determined by calculating rotational energy barriers and comparison of experimental and calculated ECD curves.Compounds 5b and 6 exhibited inhibitory effects on LPS-induced NO production in BV-2 cells,with IC_(50) values of 12.59±0.40 and 15.59±0.83μmol·L^(-1),respectively.A mechanistic study suggested that these compounds may attenuate neuroinflammation by reducing the activation of the AKT/IκB/NF-κB signaling pathway.Additionally,compounds 3a,6,and 7 demonstrated significant PTP1B inhibitory activities,with IC_(50) values of 1.52±0.34,1.39±0.11,and 1.78±0.01μmol·L^(-1),respectively.Further investigation revealed that compound 3a might inhibit LPS-induced PTP1B overexpression and NF-κB activation,thereby mitigating the neuroinflammatory response in BV-2 cells.

关键词： Bletilla striata Phenanthrene/bibenzyl trimer NO inhibition AKT/IκB/NF-κB signaling pathway PTP1B inhibitory effect

Prediction and Minimization of the Heat Treatment Induced Distortion in 8620H Steel Gear:Simulation and Experimental Verification

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 207-218页

作者： Wen Shao Mohan Yi Jinyuan Tang siyuan sun State Key Laboratory of High Performance Complex Manufacturing College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China

The considerable heat treatment induced runout value in the end face of the automobile main reducer gear is always dimensionally out of tolerance.It directly affects the dimensional accuracy,the grade of carburized and hardened gears,and the post-quenching manufacturing costs.In this study,three dimensional numerical models were developed to simulate the carburizing-quenching process of gear based on the multi-field coupling theory using DEFORM software.The results indicated that the ununiform cooling rate of the gear caused by the asymmetry of the web structure would result in the ununiform distribution of martensite,leading to the large runout value at the end face of the gear.Therefore,a novel method was proposed to minimize the heat treatment induced runout value.It was found that the heat treatment induced runout value could be effectively controlled by the addition of a compensation ring and the support of a rod structure.Further experiments showed that the average runout value of the gear end face before and after the proposed heat treatment method were about 0.023 mm and 0.059 mm respectively,which was in good agreement with the simulated results.The novel approach proposed in this study led to a reduction of the gear runout value by 70.0%‒76.9%compared to that of the original heat treatment process,which may serve as a practical and economical way to predict and minimize the heat treatment induced distortion in drive gear.

关键词： Distortion Carburizing-quenching Numerical simulation Heat treatment 8620H steel gear

Catastrophe Risk Management for Electric Power Distribution Systems:An Insurance Approach

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CSEE Journal of Power and Energy Systems 2023年第1期9卷 393-410页

作者： siyuan sun Gengfeng Li Yiheng Bian Zhaohong Bie Qianwen Hu State Key Laboratory of Electrical Insulation and Power Equipment Smart Grid Key Laboratory of Shaanxi ProvinceDepartment of Electrical EngineeringXi’an Jiaotong UniversityXi’an 710049China

High-impact,low-probability catastrophes may cause equipment damage,customer outages and serious economic losses to an aging power distribution infrastructure with low redundancy and automation.To cope with catastrophe risks faced by distribution systems(DSs),insurance is proposed as a supplement to existing resilience enhancement measures,which can provide financial aid in recovery after disasters,as well as incentives to make DSs more resilient to potential hazards.This calls for a quantitative assessment for insurance pricing that can not only predict potential losses caused by future catastrophes but also evaluate the effect of risk management measures.In this paper,a four-module actuarial framework,including hazard,vulnerability,resilience,and insurance modules,is developed to assess the catastrophe risks of DSs.Based on Monte Carlo simulation(MCS)and mixed integer linear programming(MILP),the dynamic characteristics of disasters,random failures of equipment,control measures including fault isolation,load transfer,line patrolling,manual switching,and fault repair,are comprehensively incorporated in the premium determination of catastrophe insurance.Numerical simulations are performed on the modified IEEE 33-bus test systems to illustrate the validity of the proposed catastrophe insurance schemes.

关键词： Actuarial framework catastrophe insurance distribution system risk assessment

Electrochemical synthesis of Ni doped carbon quantum dots for simultaneous fluorometric determination of Fe^(3+)and Cu^(2+)ion facilely

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Green Chemical Engineering 2023年第1期4卷 115-122页

作者： siyuan sun Yang sun Fan Yang Sai Che Xiaoyun Zhang Ge Zhang Yongfeng Li State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China

A novel Ni doped carbon quantum dots(Ni-CQDs)fluorescence probe was synthesized by facile electrolysis of monoatomic Ni dispersed porous carbon(Ni–N–C).The obtained Ni-CQDs showed a high quantum yield of 6.3%with the strongest excitation and emission peaks of 360 nm and 460 nm,and maintained over 90%of the maximum fluorescence intensity in a wide p H range of 3–12.The metal ions detectability of Ni-CQDs was enhanced by Ni doping and functional groups modification,and the rapid and selective detection of Fe^(3+)and Cu^(2+)ions was achieved with Ni-CQDs through dynamic and static quenching mechanism,respectively.On one hand,the energy band gap of Ni-CQDs was regulated by Ni doping,so that excited electrons in Ni-CQDs were able to transfer to Fe^(3+)easily.On the other hand,the abundant functional groups promoted the generation of static quenching complexation between Cu^(2+)and Ni-CQDs.In metal ions detection,the linear quantitation range of Fe^(3+)and Cu^(2+)were 100–1000μM(R^(2)=0.9955)and 300–900μM(R^(2)=0.9978),respectively.The limits of detection(LOD)were calculated as 10.17 and 7.88μM,respectively.Moreover,the fluorescence quenched by Cu^(2+)could be recovered by EDTA2-due to the destruction of the static quenching complexation.In this way,NiCQDs showed the ability to identify the two metal ions to a certain degree under the condition of Fe^(3+)and Cu^(2+)coexistent.This work paves the way of facile multiple metal ion detection with high sensitivity.

关键词： Electrolysis Ni doped CQDs Fe^(3+)detection Cu^(2+)detection Ions distinction

Electrochemical synthesis of FeN_(x) doped carbon quantum dots for sensitive detection of Cu^(2+) ion

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Green Energy & Environment 2023年第1期8卷 141-150页

作者： siyuan sun Weijie Bao Fan Yang Xingru Yan Yang sun Ge Zhang Wang Yang Yongfeng Li State Key Laboratory of Heavy Oil Processing China University of PetroleumChangpingBeijing102249China

A novel strategy was developed to fabricate FeNx-doped carbon quantum dots(Fe-N-CQDs)to detect Cu^(2+) ions selectively as a fluorescence probe.The Fe-N-CQDs were synthesized by an efficient electrolysis of a carbon cloth electrode,which was coated with monoatomic ironanchored nitrogen-doped carbon(Fe-N-C).The obtained Fe-N-CQDs emitted blue fluorescence and possessed a quantum yield(QY)of 7.5%.An extremely wide linear relationship between the Cu^(2+) concentration and the fluorescence intensity was obtained in the range from 100 nmol L^(-1) to 1000 nmol L^(-1)(R^(2)=0.997),and the detection limit was calculated as 59 nmol L^(-1).Moreover,the Fe-N-CQDs demonstrated wide range pH compatibility between 2 and 13 due to the coordination between pyridine nitrogen and Fe^(3+),which dramatically reduced the affection of the protonation and deprotonation process between H^(+) and Fe-N-CQDs.It is notable that the Fe-N-CQDs exhibited a rapid response in Cu^(2+) detection,where stable quenching can be completed in 7 s.The mechanism of excellent selective detection of Cu^(2+) was revealed by energy level simulation that the LUMO level of Fe-N-CQDs(-4.37 eV)was close to the redox potential of Cu^(2+),thus facilitating the electron transport from Fe-N-CQDs to Cu^(2+).

关键词： Electrolysis FeNx-doped CQDs Cu2t detection pH compatibility Quick response

A DQN-Based Cache Strategy for Mobile Edge Networks

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Computers, Materials & Continua 2022年第5期71卷 3277-3291页

作者： siyuan sun Junhua Zhou Jiuxing Wen Yifei Wei Xiaojun Wang School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing100876China State Key Laboratory of Intelligent Manufacturing System Technology Beijing Institute of Electronic System EngineeringBeijing100854China Ningbo sunny Intelligent Technology Co. LTDYuyao315400China Dublin City University Dublin 9Ireland

The emerging mobile edge networks with content caching capability allows end users to receive information from adjacent edge servers directly instead of a centralized data warehouse,thus the network transmission delay and system throughput can be improved significantly.Since the duplicate content transmissions between edge network and remote cloud can be reduced,the appropriate caching strategy can also improve the system energy efficiency of mobile edge networks to a great extent.This paper focuses on how to improve the network energy efficiency and proposes an intelligent caching strategy according to the cached content distribution model for mobile edge networks based on promising deep reinforcement learning algorithm.The deep neural network(DNN)and Q-learning algorithm are combined to design a deep reinforcement learning framework named as the deep-Q neural network(DQN),in which the DNN is adopted to represent the approximation of action-state value function in the Q-learning solution.The parameters iteration strategies in the proposed DQN algorithm were improved through stochastic gradient descent method,so the DQN algorithm could converge to the optimal solution quickly,and the network performance of the content caching policy can be optimized.The simulation results show that the proposed intelligent DQN-based content cache strategy with enough training steps could improve the energy efficiency of the mobile edge networks significantly.

关键词： Mobile edge network edge caching energy efficiency