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Chinese Journal of Aeronautics 2015年第2期28卷 535-544页

作者： Guo Hong Xu Jinquan Kuang xiaolin School of Automation Science and Electrical Engineering Beihang University

Improving fault tolerant performance of permanent magnet synchronous motor has always been the central issue of the electrically supplied actuator for aerospace application. In this paper, a novel fault tolerant permanent magnet synchronous motor is proposed, which is character- ized by two stators and two rotors on the same shaft with a circumferential displacement of mechanical angle of 4.5°. It helps to reduce the cogging torque. Each segment of the stator and the rotor can be considered as an 8-pole/10-slot five-phase permanent magnet synchronous motor with concentrated, single-layer and alternate teeth wound winding, which enhance the fault isola- tion capacity of the motor. Furthermore, the motor has high phase inductance to restrain the short-circuit current. In addition, an improved optimal torque control strategy is proposed to make the motor work well under the open-circuit fault and short-circuit fault conditions. Simulation and experiment results show that the proposed fault tolerant motor system has excellent fault tolerant capacity, which is able to operate continuously under the third open-circuit fault and second short- circuit fault condition without system performance degradation, which was not available earlier.

关键词： Actuator Fault isolation Fault tolerant Optimal torque control Permanent magnet moto

Inference and optimal design on step-stress partially accelerated life test for hybrid system with masked data

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Journal of Systems Engineering and Electronics 2018年第5期29卷 1089-1100页

作者： SHI xiaolin LU Pu SHI Yimin School of Electronic Engineering Xi'an University of Posts and Telecommunications Department of Applied Mathematics Northwestern Polytechnical University

Under Type-Ⅱ progressively hybrid censoring, this paper discusses statistical inference and optimal design on stepstress partially accelerated life test for hybrid system in presence of masked data. It is assumed that the lifetime of the component in hybrid systems follows independent and identical modified Weibull distributions. The maximum likelihood estimations(MLEs)of the unknown parameters, acceleration factor and reliability indexes are derived by using the Newton-Raphson algorithm. The asymptotic variance-covariance matrix and the approximate confidence intervals are obtained based on normal approximation to the asymptotic distribution of MLEs of model parameters. Moreover,two bootstrap confidence intervals are constructed by using the parametric bootstrap method. The optimal time of changing stress levels is determined under D-optimality and A-optimality ***, the Monte Carlo simulation study is carried out to illustrate the proposed procedures.

关键词： hybrid system step-stress partially accelerated life test Type-Ⅱ progressively hybrid censored and masked data statistical inference optimal test plan

New celestial assisted INS initial alignment method for lunar explorer

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Journal of Systems Engineering and Electronics 2013年第1期24卷 108-117页

作者： Weiren Wu xiaolin Ning Lingling Liu Lunar Exploration and Aerospace Engineering Center School of Instrument Science and Opto-electronics Engineering Beihang University Science and Technology on Inertial Laboratory Fundamental Science on Novel Inertial Instrument and Navigation System Technology Laboratory

In the future lunar exploration programs of China, soft landing, sampling and returning will be realized. For lunar explorers such as Rovers, Landers and Ascenders, the inertial navigation system （INS） will be used to obtain high-precision navigation information. INS propagates position, velocity and attitude by integration of sensed accelerations, so initial alignment is needed before INS can work properly. However, traditional ground-based initial alignment methods cannot work well on the lunar surface because of its low rotation rate （0.55°/h）. For solving this problem, a new autonomous INS initial alignment method assisted by celestial observations is proposed, which uses star observations to help INS estimate its attitude, gyroscopes drifts and accelerometer biases. Simulations show that this new method can not only speed up alignment, but also improve the alignment accuracy. Furthermore, the impact factors such as initial conditions, accuracy of INS sensors, and accuracy of star sensor on alignment accuracy are analyzed in details, which provide guidance for the engineering applications of this method. This method could be a promising and attractive solution for lunar explorer＇s initial alignment.

关键词： lunar exploration initial alignment inertial navigation,celestial navigation.

Quasinormal modes and late time tails of perturbation fields on a Schwarzschild-like black hole with a global monopole in the Einstein-bumblebee theory

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Science China(Physics,Mechanics & Astronomy) 2023年第10期66卷 33-43页

作者： xiaolin Zhang Mengjie Wang Jiliang Jing School of Physics and Electronics Synergetic Innovation Center for Quantum Effects and Applicationsand Institute of Interdisciplinary StudiesHunan Normal UniversityChangsha 410081China

In this paper we complete a systematic study on quasinormal modes(QNMs) and late time tails for scalar,Dirac and Maxwell fields on a spherically symmetric Schwarzschild-like black hole with a global monopole in the Einstein-bumblebee *** look for QNMs,we solve the equations of motion for all perturbation fields considered herein numerically,by employing both the matrix and the WKB methods,and find good agreements for numeric data obtained by these two techniques in the regime when both are *** impact of the bumblebee parameter c,the monopole parameter η^(2),and the multipole number l on the fundamental quasinormal frequency are analyzed in *** results are shown in terms of the quasinormal frequency measured by √1+c M ,where M is a black hole mass *** observe,by increasing the parameter c(η^(2)) with fixed first few l,that the real part of QNMs increases for all spin fields;while the magnitude of the imaginary part decreases for scalar and Dirac fields but increases for Maxwell *** increasing the multipole numberlwith fixed other parameters,we disclose that the real part of QNMs for all spin fields increases while the magnitude of the imaginary part decreases for scalar and Dirac fields but increases for Maxwell *** the eikonal limit(l>>n),QNMs for all spin fields coincide with each other and the real part scale linearly with *** particular,the asymptotic QNMs approach the corresponding results given by the first order WKB formula,and only the real part of QNMs is dependent on the bumblebee and monopole *** addition,it is shown that the late time behavior is determined not only by the multipole number but also by the bumblebee and monopole parameters,and is distinct for bosonic and fermonic ***,the presence of the bumblebee(monopole) field makes the spin fields decay *** results indicate,both in the context of QNMs and late time tails,that the bumblebee field and the monopole field play the same ro

关键词： Einstein-bumblebee theory perturbation fields dynamic evolution

Modulation recognition of communication signals based on SCHKS-SSVM

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Journal of Systems Engineering and Electronics 2017年第4期28卷 627-633页

作者： xiaolin Zhang Jian Chen Zhiguo Sun College of Information and Communication Engineering Harbin Engineering UniversityHarbin 150001China Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory Shijiazhuang 050000China

A novel modulation recognition algorithm is proposed by introducing a Chen-Harker-Kanzow-Smale (CHKS) smooth function into the C-support vector machine deformation algorithm. A set of seven characteristic parameters is selected from a range of parameters of communication signals including instantaneous amplitude, phase, and frequency. And the Newton-Armijo algorithm is utilized to train the proposed algorithm, namely, smooth CHKS smooth support vector machine (SCHKS-SSVM). Compared with the existing algorithms, the proposed algorithm not only solves the non-differentiable problem of the second order objective function, but also reduces the recognition error. It significantly improves the training speed and also saves a large amount of storage space through large-scale sorting problems. The simulation results show that the recognition rate of the algorithm can batch training. Therefore, the proposed algorithm is suitable for solving the problem of high dimension and its recognition can exceed 95% when the signal-to-noise ratio is no less than 10 dB.

关键词： communication signal modulation recognition support vector machine smooth function

Metabolic Dysfunction-associated Fatty Liver Disease (MAFLD) and Viral Hepatitis

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Journal of Clinical and Translational Hepatology 2022年第1期10卷 128-133页

作者： xiaolin Wang Qing Xie Department of Infectious Diseases Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghaiChina

A new definition of metabolic dysfunction-associated fatty liver disease(MAFLD)was proposed in *** change from nonalcoholic fatty liver disease(NAFLD)to MAFLD highlights the metabolic abnormalities that accompany fatty *** diagnosis of MAFLD does not require exclusion of secondary causes of liver diseases and alcohol ***,MAFLD may coexist with other types of liver diseases,such as viral hepatitis,a disease that remains the most common cause of liver disease-related *** the increasing prevalence of MAFLD,patients with coincidental MAFLD and viral hepatitis are frequently encountered in clinical *** this review,we mainly summarize the mutual relationship between hepatitis B/C and systematic metabolism dysfunction related to *** discuss the impact of MAFLD on progression of viral hepatitis and the *** unaddressed clinical problems related to concomitant MAFLD and viral hepatitis are also identified.

关键词： Metabolic dysfunction-associated fatty liver disease Chronic hepatitis B Chronic hepatitis C

Machining Characteristics in Cryogenic Grinding of SiCp/Al Composites

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Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 869-874页

作者： Li Zhou Shutao Huang xiaolin Yu School of Mechanical Engineering Shenyang Ligong University

In this study, liquid nitrogen was applied to grind SiCp/Al composites with high volume fraction and large SiC particle at different levels of cutting conditions, and the effects of grinding depth and speed on grinding force, surface morphology, and surface roughness were investigated. At the same time, the effect of cryogenic cooling was also compared with that of conventional wet grinding. The experimental results indicated that cryogenic cooling is effective in enhancing supporting function of Al matrix to the SiC particles and improving surface quality. Additionally, the brittle fracture of SiC particles was suppressed and some ductile streaks on SiC particle could be observed.

关键词： SiCp/Al composites Grinding Cryogenic machining Surface quality

Active zone stability:insights from fly neuromuscular junction

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Neural Regeneration Research 2015年第5期10卷 677-678页

作者： xiaolin Tian Chunlai Wu Neuroscience Center of Excellence Department of Cell Biology and AnatomySchool of MedicineLouisiana State University Health Sciences Center

The presynaptic active zone is a dynamic structure that orchestrates regulated release of neurotrans- mitters. Developmental and aging processes, and changes in neuronal network activity can all modulate the number, size and composition of active zone and thereby synaptic efficacy. However, very little is known about the mechanism that controls the structural stability of active zone. By study- ing a model synapse, the Drosophila neuromuscular iunction, our recent work shed light on how two scaffolding proteins at the active zone regulate active zone stability by promoting a localized dephos- phorylation event at the nerve terminal. Here we discuss the major insights from our findings and their implications for future research.

关键词： active zone stability Drosophila neuromuscular junction dephosphorylation Liprin-α Syd-1 PP2A GSK-3β

Multi-constellation GNSS precise point positioning with multi-frequency raw observations and dual-frequency observations of ionospheric-free linear combination

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Satellite Navigation 2020年第1期1卷 68-80页

作者： Xiangdong An xiaolin Meng Weiping Jiang GNSS Research Center Wuhan University129 Luoyu RoadWuhan 430079China Nottingham Geospatial Institute University of NottinghamNottingham NG72TUUK.

Precise point positioning(PPP)is famous for its capability of high-precision positioning with just one station as long as the receiver can receive global navigation satellite system(GNSS)*** the rapid development of BDS and Galileo,the number of available satellites for positioning has increased *** addition,GPS III,GLONASS-K,BDS,and Galileo satellites can transmit triple-frequency *** potentials of multi-constellation GNSS PPP requires further analysis on a global ***,we selected 96 multi-GNSS experiment(MGEX)stations with a global distribution and used 1 week’s data to assess the PPP *** results show that the PPP based on multi-frequency raw observations with spatial and temporal constraints has better performance than PPP using dual-frequency ionospheric-free *** main contribution of multi-constellation GNSS PPP is to shorten the convergence *** convergence time for GPS PPP is approximately 40 min,which can be shortened to less than 20 min in multi-GNSS *** convergence,the positioning accuracy of multi-GNSS PPP is improved by 0.5 to 1.0 cm compared with GPS or GLONASS *** positioning accuracy of multi-GNSS could be further improved in the future with the BDS and Galileo precise products of orbits,clock and phase center offset/variation.

关键词： Precise point positioning Multi-frequency and multi-constellation GNSS PPP convergence Multi-GNSS experiment

Anionic polymerization initiated by lithium amides for preparing high molecular weight polyacrylonitrile

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Chinese Chemical Letters 2019年第2期30卷 473-476页

作者： xiaolin Shi Jingyang Jiang State Key Laboratory of Fine Chemicals Faculty of Chemical Environmental and Biological Science and Technology Dalian University of Technology

Lithium amides have been proved to be effective anionic initiators for the anionic polymerization of acrylonitrile to get high molecular weight polyacrylonitrile in this study. Polyacrylonitrile with weightaverage molecular weight ranging from 1.02 × 10~6 g/mol to 1.23 ×10~6 g/mol (M_w/M_n= 1.9-2.2) could be prepared utilizing lithium amides derived from diisopropylamine, diethylamine, hexamethyldisilazane,dicyclohexylamine, and 2,2,6,6-tetramethylpiperidine as initiators. The polymerization of acrylonitrile proceeded in a homogeneous manner in N,N-di methyl for mamide and insignificant contribution of side reactions was confirmed.

关键词： Anionic polymerization Acrylonitrile High molecular weight polymer Lithium amides Polyacrylonitrile