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Time-varying parameters estimation with adaptive neural network EKF for missile-dual control system

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Journal of Systems Engineering and Electronics 2024年第2期35卷 451-462页

作者： YUAN Yuqi ZHOU Di li Junlong lou Chaofei School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing Institute of Electronic System Engineering Beijing 100854China

In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.

关键词： long-short-term memory(LSTM)neural network extended Kalman filter(EKF) rolling training time-varying parameters estimation missile dual control system

Discovery of alkaloids from the leaves of Isatis indigotica Fortune with neuroprotective activity

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Chinese Journal of Natural Medicines 2021年第9期19卷 680-685页

作者： XI Yu-Fei lou li-li HAN Feng-Ying WANG Xiao-Bo HUANG Xiao-Xiao YAO Guo-Dong SONG Shao-Jiang Key Laboratory of Computational Chemistry-Based Natural Antitumor Drug Research&Development Liaoning ProvinceSchool of Traditional Chinese Materia MedicaShenyang Pharmaceutical UniversityShenyang 110016China Chinese People's liberation Army Logistics Support Force No.967 Hospital Dalian 116000China

Seven alkaloids including five undescribed ones(1 a/1 b,2,3 and 5)were obtained from the leaves of Isatis indigotica *** structures were established by extensive spectroscopic *** absolute configurations of compounds 1 a,1 b,3 and 5 were determined by comparison of the experimental and calculated electronic circular dichroism(ECD)***,the neuroprotective effects of all the isolates against H_(2)O_(2)-induced injury in SH-SY5 Y cells were evaluated in vitro by MTT ***,Annexin V-FITC/PI double staining was performed,while the activities of antioxidant enzymes(SOD,CAT and GSH-Px)for compounds 1 a and 1 b were measured.

关键词： Isatis indigotica Alkaloids Neuroprotective effects Structure elucidation

Distributed Harmonic Power Sharing with Voltage Distortion Suppression in Islanded Microgrids Considering Non-linear Loads

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 117-128页

作者： Guannan lou Shanlin li Wei Gu Quan Yang School of Electrical Engineering Southeast UniversityNanjingJiangsu 210096China the Jiangsu Provincial Key Laboratory of Smart Grid Technology and Equipment Southeast University Dongguan Power Supply Bureau of Guangdong Power Grid Company Guangdong 523000China

In contemporary power grids or microgrids,harmonic distortion has emerged as one of the critical power quality issues for utility power grids,which has escalated especially due to the high penetration of power-electronic-converter-interfaced distributed generation(DG).This paper first illustrates the prevalent dispute revolving around the harmonic power sharing and distortion restraint,and subsequently proposes a consensusbased framework that facilitates an accurate sharing of harmonics among multi-DGs connected in parallel,with an effective suppression of the output voltage *** with the majority of existing studies addressing the issue of voltage harmonics at the point of common coupling(PCC),our method primarily emphasizes on the output voltage distortion since the power quality requirement for certain local critical loads is often known to be *** the help of adaptive regulation,the overall distortion produced at the output terminals of DGs can be retained within an acceptable *** working principle of the proposed control method,which is not only easy to implement but also independent of model parameters,is further described in *** the small-signal dynamic model,the system stability and robustness are *** hardware-in-the-loop(HIL)simulations aid in determining the outcome of the proposed strategy in microgrid control.

关键词： Distributed generation droop control harmonic power sharing microgrid voltage distortion mitigation

Single-atom Zn confined in hierarchical hollow microstructure as an acid/base-resistant microwave absorption materials

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Nano Research 2024年第8期17卷 6785-6794页

作者： Yue lou Jiao li Xiaokun li Zhenyu Zhu Zhan Shi Biao Xu School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China

Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme ***,we demonstrate the successful synthesis of the N-doped porous carbon(NC)material with hierarchical pore structure by the spray pyrolysis *** large specific surface area(SBET=707.53 m^(2)·g^(−1))of materials enables multiple scattering of incident electromagnetic waves,and N doping greatly enhances the electrical conductivity of the ***,single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms,induce the center of polarization,and thus change the dielectric and electronic properties of the host *** porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature *** the same time,they can also be used in various complex environments,such as acidic and basic ***,NC-1000,with high surface area,low density,and good chemical stability,obtained a minimum reflection loss(RLmin)of−50.5 dB and an effective absorption bandwidth(EAB)exceeding 5.1 GHz at the thickness of 1.9 *** soaking in the strong acid and base solution,the electromagnetic wave absorption performance of the material decreased by<15%.Widely available raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.

关键词： hierarchical hollow microstructure microwave absorption metal-organic framework(MOF) impedance matching singleatom Zn acid/base-resistant

Observation of optical rogue waves in 2D optical lattice

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Chinese Optics Letters 2024年第7期22卷 77-80页

作者： Meng li Jie Song Fuqiang li Cibo lou School of Physical Science and Technology Ningbo UniversityNingbo 315211China

We use a broad Gaussian beam with perturbations to motivate rogue waves(RWs)in a two-dimensional optical-induced *** a linear situation,we fail to observe ***,under a nonlinear condition,the probability of RWs in the lattice is less than that in a homogeneous ***,we obtain a shorter long-tail distribution of probability density function in an optical lattice.

关键词： optical rogue waves spatial rogue waves optical-induced lattice

Stability analysis of a liquid crystal elastomer self-oscillator under a linear temperature field

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 337-354页

作者： Haiyang WU Jiangfeng lou Biao ZHANG Yuntong DAI Kai li School of Civil Engineering Anhui Jianzhu UniversityHefei 230601China

Self-oscillating systems abound in the natural world and offer substantial potential for applications in controllers,micro-motors,medical equipments,and so ***,numerical methods have been widely utilized for obtaining the characteristics of self-oscillation including amplitude and ***,numerical methods are burdened by intricate computations and limited precision,hindering comprehensive investigations into self-oscillating *** this paper,the stability of a liquid crystal elastomer fiber self-oscillating system under a linear temperature field is studied,and analytical solutions for the amplitude and frequency are ***,we establish the governing equations of self-oscillation,elucidate two motion regimes,and reveal the underlying ***,we conduct a stability analysis and employ a multi-scale method to obtain the analytical solutions for the amplitude and *** results show agreement between the multi-scale and numerical *** research contributes to the examination of diverse self-oscillating systems and advances the theoretical analysis of self-oscillating systems rooted in active materials.

关键词： self-oscillation stability analysis multi-scale method liquid crystal elastomer linear temperature field

Orbit and clock products for quad-system satellites with undifferenced ambiguity fixing approach

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Satellite Navigation 2024年第1期5卷 125-139页

作者： Jiaqi Wu Xingxing li Yongqiang Yuan Keke Zhang Xin li Jiaqing lou Yun Xiong School of Geodesy and Geomatics Wuhan University129 Luoyu RoadWuhan430079China Hubei Luojia Laboratory 129 Luoyu RoadWuhan430079China German Research Centre for Geosciences GFZ Telegrafenberg14473PotsdamGermany Technische Universitat Berlin(TUB) Straße Des 17.Juni10623BerlinGermany

Integer Ambiguity Resolution(IAR)can significantly improve the accuracy of GNSS Precise Orbit Determination(POD).Traditionally,the IAR in POD is achieved at the Double Differenced(DD)*** this contribution,we develop an Un-Differenced(UD)IAR method for Global Positioning System(GPS)+BeiDou Navigation Satellite System(BDS)+Galileo navigation satellite system(Galileo)+Global'naya Navigatsionnaya Sputnikovaya Sistema(GLONASS)quad-system POD by calibrating UD ambiguities in the raw carrier phase and generating the so-called carrier *** on this method,we generate the UD ambiguity-fixed orbit and clock products for the Wuhan Innovation Application Center(IAC)of the International GNSS Monitoring and Assessment System(iGMAS).One-year observations in 2020 from 150 stations are employed to investigate performance of orbit and clock ***,the UD Ambiguity Resolution(AR)yields more resolved integer ambiguities than the traditional DD AR,scaling up to 9%,attributable to its avoidance of station baseline *** from the removal of ambiguity parameters,the computational efficiency of parameter estimation undergoes a substantial 70%*** with the float solution,the orbit consistencies of UD AR solution achieve the accuracy of 1.9,5.2,2.8,2.1,and 2.7 cm for GPS,BeiDou-2 Navigation Satellite System(BDS-2),BeiDou-3 Navigation Satellite System(BDS-3),Galileo,and GLONASS satellites respectively,reflecting enhancements of 40%,24%,54%,34%,and 42%.Moreover,the standard deviations of Satellite Laser Ranging(SLR)residuals are spanning 2.5–3.5 cm,underscoring a comparable accuracy to the DD AR solution,with discrepancies below 5%.A notable advantage of UD AR lies in its capability to produce the Integer Recovered Clock(IRC),facilitating Precise Point Positioning(PPP)AR without requiring additional Uncalibrated Phase Delay(UPD)*** assess the performance of quad-system kinematic PPP based on IRC,a network comprising 120 stations is uti

关键词： Multi-GNSS Precise orbit determination Integer recover clock Undifferenced ambiguity resolution iGMAS innovation application center

Visible-light-induced Synthesis of Organic Peroxides via Decarboxylative Couplings of Carboxylic Acids,Alkenes and tert-Butyl Hydroperoxide

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Chemical Research in Chinese Universities 2024年第5期40卷 863-873页

作者： HUANG Qiuwei lou Chenhao LV Leiyang li Zhiping Key Laboratory of Advanced light Conversion Materials and Biophotonics School of Chemistry and Life ResourcesRenmin University of ChinaBeijing100872P.R.China

Herein,we present a photoinduced,CeCl_(3)-catalyzed three-component decarboxylative reaction that couples carboxylic acids,alkenes and tert-butyl hydroperoxide for the formation of various organic *** ligand-to-metal charge transfer(LMCT)excitation mode allows the decarboxylative alkylation-peroxidation reaction to occur under mild conditions,and is well applicable to primary,secondary and tertiary carboxylic acids and styrene derivatives.

关键词： Visible-light catalysis Difunctionalization Carboxylic acid Alkene Organic peroxide

A new 4-Ti-added polyoxometalate

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Tungsten 2024年第2期6卷 465-471页

作者： Hai-lou li Chen lian Guo-Yu Yang MOE Key Laboratory of Cluster Science School of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 102488China

A new inorganic–organic hybrid 4-Ti-added polyoxometalate:[H_(2)N(CH_(3))_(2)]_(2)Na_(3)H_(5)[{Ti(C_(2)O_(4))(H_(2)O)}_(2){Ti(C_(2)O_(4))}_(2)(B-β-SbW_(9)O_(33))_(2)]·22H_(2)O(1)has been successfully made and further characterized by infrared spectroscopy,thermogravimetric analysis,powder X-ray diff raction and single-crystal X-ray diff *** polyoxoanion of 1 exhibits a Krebs-type structure that is constructed from two[B-β-SbW_(9)O_(33)]^(9)−fragments fused together by a belt of four additional Ti atoms decorated by oxalate ***,1 as a heterogeneous catalyst exhibits high activity for Knoevenagel condensation under mild reaction conditions.

关键词： Polyoxometalate Ti-added POM Krebs-type structure Knoevenagel condensation