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An improved nonlinear onboard adaptive model for aero-engine performance control

Chinese Journal of Aeronautics 2023年第10期36卷 317-334页

作者： qian CHEN Hanlin sheng Tianhong ZHANG Jiangsu Province Key Laboratory of Aerospace Power System College of Energy and Power EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

The onboard adaptive model can achieve the online real-time estimation of performance parameters that are difficult to measure in a real aero-engine,which is the key to realizing modelbased performance *** must possess satisfactory numerical stability and estimation ***,the positive definiteness of the state covariance matrix may be destroyed in filter estimation because of the existence of some uncertain factors,such as the accumulated measurement error,noise,and disturbance in the strongly nonlinear engine system,inevitably causing divergence of estimates of Cholesky decomposition-based Spherical Unscented Kalman Filter(SUKF).Therefore,this paper proposes an improved SUKF algorithm(iSUKF)and applies it to the performance degradation estimation of the *** to SUKF,the iSUKF mainly replaces the Cholesky decomposition with the Singular Value Decomposition(SVD),which is numerically stable without any strict requirement for the state covariance ***,a correction factor is designed to assess the measurement deviation between the real engine and the nonlinear onboard model to correct the state covariance matrix,thus maintaining better numerical stability of parameters estimated by the ***,an offline correction strategy is also proposed to eliminate the influence of the degradation of unestimated health parameters or the filter’s inadequate estimation of the coupled health *** action effectively promotes the onboard adaptive model’s estimation accuracy concerning the degradation of the engine’real health parameters and its performance ***,the simulation results show that the iSUKF can maintain the numerical stability of the filter’s estimation of health *** with the existing methods,the offline correction strategy improves the estimation accuracy of the iSUKF-based nonlinear onboard adaptive model for the performance parameters of the real engine by more than 50%.The proposed met

关键词： Aero-engine Onboard adaptive model Spherical unscented Kalman filter Parameter estimation iSUKF

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Asteroseismology of 16 Kepler Solar-like Stars:Stellar Parameters and the Effects of Element Diffusion

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Research in Astronomy and Astrophysics 2023年第7期23卷 206-220页

作者： Shuai Wang qian-sheng Zhang Yunnan Observatories Chinese Academy of Sciences396 YangfangwangGuandu DistrictKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China International Centre of Supernovae Yunnan Key LaboratoryKunming 650216China

Element diffusion has small but significant effects on the structure of the stellar *** is interesting to investigate the effects of element diffusion using *** have constructed two grids of stellar models,one with diffusion and one without,for solar-like stars with masses between 0.9 and 1.4 solar masses,and varied initial helium abundance and *** oscillation frequencies of all stellar models have also been *** Hermite cubic polynomials are adopted to interpolate stellar p-mode frequencies at an arbitrary age on a stellar evolutionary *** have investigated 16 Kepler solar-like stars by comparing the model frequencies with *** suggested ranges of stellar parameters and some global variables are *** all stars,the best model reproduces the observational frequencies with aχ^(2)of the order of *** has been found that element diffusion is important in modeling solar-like *** diffusion,the best value of the initial helium abundance is below the primordial helium abundance from Big Bang *** diffusion is taken into account,the required initial helium abundance increases to be higher than the primordial *** also generally improves the frequency fitting results by reducing the minimum ofχ^(2).Investigation of the second difference of the oscillation frequencies on KIC 8694723 and KIC 10454113 indicates that the current model of element diffusion may underestimate the strength of settling.

关键词： asteroseismology diffusion stars:interiors stars:abundances

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Orbital period correction and light curve modeling of the W-subtype shallow contact binary OW Leo

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Research in Astronomy and Astrophysics 2021年第2期21卷 24-30页

作者： Xiao Zhou sheng-Bang qian Yunnan Observatories Chinese Academy of Sciences(CAS)Kunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China University of the Chinese Academy of Sciences Beijing 100049China

Orbital period and multi-color light curves’investigation of OW Leo are presented for the first *** orbital period of OW Leo is corrected from P=0.325545 days to P=0.32554052 days in our work,and the observational data from the All-Sky Automated Survey for Super Novae(ASAS-SN)are used to test the newly determined orbital ***,the phased light curves are calculated with the new period and the Wilson-Devinney program is applied to model the light curves,which reveal that OW Leo is a W-subtype shallow contact binary system(q=3.05,f=12.8%).The absolute physical parameters of the two component stars are estimated to be M_(1)=0.31(1)M_(⊙),M_(2)=0.95(3)M_(⊙),R_(1)=0.63(1)R⊙,R_(2)=1.04(1)R_(⊙),L_(1)=0.43(1)L_(⊙)and L_(2)=1.01(2)L_(⊙).The evolutionary status shows that the more massive star is less evolved than the less massive *** Leo has very low metal abundance,which means its formation and evolution are hardly influenced by any additional *** is formed from an initially detached binary system through nuclear evolution and angular momentum loss via magnetic braking,and has passed a very long time of main sequence evolution.

关键词： techniques photometric-binaries eclipsing-stars evolution

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Two particular EA-type binaries in the globular cluster ω Centauri

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Research in Astronomy and Astrophysics 2013年第7期13卷 827-834页

作者： Kai Li sheng-Bang qian National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

We analyzed the B and V light curves of two EA-type binaries V211 and NV358 for the first time using the Wilson-Devinney code. Our analysis shows that V211 is a typical Algol-type binary and NV358 is a well detached binary system. As the two binaries are definite members of ω Centauri due to their proper motion, we estimated their physical parameters, obtaining M1 = 1.13 4±0.03 M⊙, R1 = 0.98±0.01 R⊙, M2 = 0.33 ±0.01 M⊙ and R2 = 0.92 ±0.01 R⊙ forV211; M1 = 1.304-0.05 M⊙, R1 = 1.03±0.01 R⊙, M2 = 0.58±0.02 M⊙ and R2 = 0.78±0.01 R⊙ for NV358. On the color-magnitude diagram of ω Centauri, V211 is located in the faint blue straggler region and its primary component is more massive than a star at the main-sequence turnoff. Therefore, V211 is a blue straggler and was formed by mass transfer from the secondary component to the primary. The age of NV358 is less than 1.93 Gyr, indicating that it is much younger than the first generation of stars in ω Centaufi. Like NV364 in ω Centaufi, NV358 should be a second-generation binary.

关键词： galaxies: globular clusters: individual (ω Centauri) - stars: binaries:close - stars: binaries: eclipsing - stars: blue stragglers - stars: individual (V211 NV358)

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Turbulence properties in the solar convection envelope:properties of the overshooting regions

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Chinese Journal of Astronomy and Astrophysics 2009年第5期9卷 585-595页

作者： qian-sheng Zhang Yan Li National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China

We apply the turbulent convection model （TCM） to investigate properties of turbulence in the solar convective envelope, especially in overshooting regions. The results show TCM gives negative turbulent heat flux uτ＇T＇ in overshooting regions, which is similar to other nonlocal turbulent convection theories. The turbulent temperature fluctuation T＇T＇ shows peaks in overshooting regions. Most important, we find that the downward overshooting region below the base of the solar convection zone is a thin cellular layer filled with roll-shaped convective cells. The overshooting length for the temperature gradient is much shorter than that for element mixing because turbulent heat flux of downward and upward moving convective cells counteract each other in this cellular overshooting region. Comparing the models＇ sound speed with observations, we find that taking the convective overshooting into account helps to improve the sound speed profile of our nonlocal solar models. Comparing the p-mode oscillation frequencies with observations, we validated that increasing the diffusion parameters and decreasing the dissipation parameters of TCM make the p-mode oscillation frequencies of the solar model be in better agreement with observations.

关键词： convection - turbulence - Sun helioseismology

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A high-safety active/passive hybrid control approach for compressor surge based on nonlinear model predictive control

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Chinese Journal of Aeronautics 2023年第1期36卷 396-412页

作者： Hanlin sheng qian CHEN Jie ZHANG Tianhong ZHANG Jiangsu Province Key Laboratory of Aerospace Power System College of Energy and Power EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China

Surge active control can expand the stable operating range of the ***,the difficulty of flow measurement,dynamic uncertainty disturbance,actuator delay characteristics,hard constraints of control variable,and system security measures have not been fully considered in the existing active control system,which significantly hinders its engineering ***,a nonlinear model predictive surge active control method is first presented based on flow estimator designed by using a continuous-time Kalman filter for dealing with the hard constraint of control variable and the impact of actuator delay of compression system with dynamic ***,a high-safety active/surge passive hybrid control strategy is designed,dominated by the surge active control and supplemented by the surge passive control,to ensure the compression system’s safe and stable ***,the simulation results suggest that the flow estimator accurately estimates the compressor *** considering the delay impact of the actuators and sensors and measurement noise on the system,the proposed method exhibits stronger robustness than the existing *** active/surge passive hybrid control strategy can successfully ensure the compression system’s safe and stable *** paper is of high practical significance for the engineering application of future compressor surge active control technologies.

关键词： Active control Compressor surge Flow estimator Hybrid system Model predictive control

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Further Results on Stability Analysis for Sampled-Data Systems via Refined Semi-Looped-Functional

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Journal of Systems Science & Complexity 2024年第1期37卷 318-328页

作者： sheng Zhaoliang XU shengyuan MA qian ZHANG Baoyong School of Automation Nanjing University of Science and TechnologyNanjing 210094China

This paper investigates the stability problem for sampled-data systems by adopting a refined semi-looped-functional,which is with the following two ***,the new functional term is with a new integral vectorη0,which contains sampling information of the systems and associates two commonly used ***,the vectorη0 is combined into various zero equations for processing the functional,especially where a new equation is derived fromη*** on the refined functional,further stability results for sampled-data systems are *** the effectiveness of the results is numerically verified through two examples at the end.

关键词： Integral vector sampled-data systems semi-looped-functional stability analysis.

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Novel high-safety aeroengine performance predictive control method based on adaptive tracking weight

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Chinese Journal of Aeronautics 2024年第7期37卷 352-374页

作者： qian CHEN Hanlin sheng Jie ZHANG Jiacheng LI College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Increasing attention has been attracted to the dynamic performance and safety of advanced performance predictive control systems of the next-generation *** latest research demonstrates that Subspace-based Improved Model Predictive Control(SIMPC)can overcome the difficulty in solving the predictive model in MPC/NMPC ***,applying constant design parameters cannot maintain consistent control effects in all ***,the designed system relies too much on sensor-measured data,and thus it is difficult to thoroughly validate the safety of the system because of its high *** means that any potential hardware/software faults will endanger the ***,this paper first presents a novel nonlinear mapping relationship to adaptively tune the tracking weight online with the change of Power Lever Angle(PLA)and real-time relative tracking ***,without introducing additional design parameters,an Adaptive Tracking Weight-based SIMPC(ATW-SIMPC)controller is designed to improve the control performance in all operating states ***,a Primary/Backup Hybrid Control(PBHC)strategy with the ATW-SIMPC controller as the primary system and the traditional speed(Nf)controller as the backup system is proposed to ensure *** designed affiliated switching controller and the real-time monitor therein can be used to realize reasonable and smooth switching between primary/backup systems,so as to avoid bump *** PBHC system switches to the Nf controller when the ATW-SIMPC controller is wrong because of potential hardware/software faults;otherwise,the ATW-SIMPC controller keeps acting on the *** main results prove that the ATW-SIMPC controller with the optimal nonlinear mapping relationship,compared with the existing SIMPC controller,uplifts the dynamic control performance by 32%and reduces overshoots to an allowable limit,resulting in a better control effect in full *** comparison results consistently i

关键词： Aeroengine Model predictive control Hybrid system Adaptive weight Safety

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RATIO OF CHARMED BARYON TO MESON IN e^(+)e^(-) ANNIHILATION

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Chinese Physics Letters 1990年第3期7卷 109-112页

作者： CHEN E-sheng WU qian Department of Physics Shandong UniversityJinan 250100

A method to determine the value of the ratio of charmed baryon to meson in e^(+)e^(-) annihilation is *** the data of CLEO,HRS and MARK Ⅱ groups,we obtain f≡B_(c)/M_(c)=0.21±0.05,0.24±0.08 and 0.33±0.05,for √s=5... 详细信息

关键词： annihilation meson charm

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Hyposmia: a possible biomarker of Parkinson's disease

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Neuroscience Bulletin 2014年第1期30卷 134-140页

作者： qian Xiao sheng Chen Weidong Le Institute of Neurology Ruijin Hospital Shanghai Jiao Tong University School of Medicine Institutes of Translational Medicine 1st Affiliated Hospital of Dalian Medical Universtiy

Hyposmia, identified as reduced sensitivity to odor, is a common non-motor symptom of Parkinson＇s disease （PD） that antedates the typical motor symptoms by several years. It occurs in -90% of early-stage cases of PD. In addition to the high prevalence, the occurrence of hyposmia may also predict a higher risk of PD. Investigations into hyposmia and its relationship with PD may help elucidate the underlying pathogenic mechanisms. This review provides an update of olfactory dysfunction in PD and its potential as a biomarker for this devastating disease.

关键词： hyposmia Parkinson's disease olfaction biomarker

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