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Active flutter suppression of nonlinear fin-actuator system via inverse system and immersion and invariance method

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Chinese Journal of Aeronautics 2024年第4期37卷 343-362页

作者： Jin lu Zhigang wu Chao yang Chinese Aeronautical Establishment Beijing 100029China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

Structural nonlinearities such as freeplay will affect the stability and even flight safety of the fin-actuator *** is a lack of a practical method for designing Active Flutter Suppression (AFS) control laws for nonlinear fin-actuator systems.A design method for the AFS controller of the nonlinear all-movable fin-electromechanical actuator system is established by combining the inverse system and the Immersion and Invariance (I&I) ***,the composite control law combining the inverse system principle and internal model control is used to offset the nonlinearity and dynamics of the actuator,so that its driving torque can follow the ideal ***,the ideal torque of the actuator is designed employing the I&I *** unfavorable oscillation of the fin is suppressed by making the output torque of the actuator track the ideal *** simulation results reveal that the proposed AFS method can increase the flutter speed of the nonlinear finactuator system with freeplay,and a set of controller parameters is also applicable for wider freeplay within a certain *** power required for the actuator does not exceed the power that can be provided by the commonly used aviation *** method can also resist a certain level of noise and external disturbance.

关键词： Aeroelasticity Active flutter suppression Fin-actuator system Freeplay Inverse system Immersion and invariance

A GNSS Anti-Spoofing Technique Based on the Spatial Distribution Characteristic of the Residual Vectors

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Tsinghua Science and Technology 2024年第2期29卷 457-468页

作者： Qi'an wu Xiaowei Cui Mingquan lu Pengxiang yang Peng wu Department of Electronic Enginnering Tsinghua UniversityBeijing 100084China Xi’an Modern Control Technology Research Institute Xi’an 710065China

Anti-spoofing is becoming a crucial technique for applications with high navigation accuracy and reliability ***-spoofing technique based on Receiver Autonomous Integrity Monitoring(RAIM)is a good choice for most Global Navigation Satellite System(GNSS)receivers because it does not require any change to the hardware of the ***,the conventional RAIM method can only detect and mitigate a single spoofing *** improved RAIM methods can deal with more spoofing signals,but the computational complexity increases dramatically when the number of satellites in view increase or need additional *** paper proposes a new RAIM method,called the SRV-RAIM method,which has a very low computation complexity regardless of the number of satellites in view and can deal with any number of spoofing *** key to the new method is the spatial distribution characteristic of the Satellites'Residual Vectors(SRV).In replay or generative spoofing scenarios,the pseudorange measurements of spoofing signals are consistent,the residual vectors of real satellites and those of spoofing satellites have good separation characteristics in spatial *** on this characteristic,the SRV-RAIM method is proposed,and the simulation results show that the method can separate the real signals and the spoofing signals with an average probability of 86.55%in the case of 12 visible satellites,regardless of the number of spoofing *** to the conventional traversal-RAIM method,the performance is only reduced by 3.59%,but the computational cost is reduced by 98.3%,so most of the GNSS receivers can run the SRV-RAIM algorithm in time.

关键词： Global Navigation Satellite System(GNSS) anti-spoofing Receiver Autonomous Integrity Monitoring(RAIM) Satellites'Residual Vectors(SRV)

Interpolated Bumpless Transfer Control for Asynchronously Switched Linear Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1579-1590页

作者： Shengao lu Tong wu Lixian Zhang Jianan yang Ye Liang the School of Astronautics Harbin Institute of TechnologyHarbin 150080China the Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore IEEE

This paper revisits the problem of bumpless transfer control(BTC) for discrete-time nondeterministic switched linear systems. The general case of asynchronous switching is considered for the first time in the field of BTC for switched systems. A new approach called interpolated bumpless transfer control(IBTC) is proposed, where the bumpless transfer controllers are formulated with the combination of the two adjacent modedependent controller gains, and are interpolated for finite steps once the switching is detected. In contrast with the existing approaches, IBTC does not necessarily run through the full interval of subsystems, as well as possesses the time-varying controller gains(with more flexibility and less conservatism) achieved from a control synthesis allowing for the stability and other performance of the whole switched system. Sufficient conditions ensuring stability and H_(∞) performance of the underlying system by IBTC are developed, and numerical examples verify the theoretical findings.

关键词： Asynchronous switching bumpless transfer H_∞control switched systems

Molecular Modeling Studies of 4-Hydroxyamino α-Pyranone Carboxamide Analogues as Hepatitis C Virus Inhibitor Using 3D-QSAR and Molecular Docking

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Chinese Journal of Structural Chemistry 2020年第6期39卷 1135-1145页

作者： TONG Jian-Bo wu lu-yang LEI Shan WANG Tian-Hao MA yang-Min College of Chemistry and Chemical Engineering Shaanxi University of Science and TechnologyXi'an 710021China Shaanxi Key Laboratory of Chemical Additives for Industry Xi'an 710021China

In this paper, 42 4-hydroxyamino α-pyranone carboxamide analogues as Hepatitis C Virus(HCV) inhibitor 3 D-QSAR model was built based on Topomer CoMFA. The non-cross-validation(r2), cross-validation(q2), correlation coefficient of external validation(Q ext2), non-cross validated standard error(SD), standard error of prediction(SDCV) and F are 0.909, 0.615, 0.967, 0.13, 0.28 and 37.287, respectively. The obtained Topomer CoMFA model has good estimation stability and prediction capability. Topomer Search was employed as a tool for virtual screening in lead-like compounds in the ZINC database. Then, 6 R1 groups and 4 R2 groups with higher contribution values were employed to alternately substitute for the R1 and R2 of the template compound 21 with the highest bioactivity. As a result, 22 new molecules with higher activity than that of the template molecule were designed successfully. The Topomer Search technology could be effectively applied to screen and design new 4-hydroxyamino α-pyranone carboxamide analogues. The molecular docking method was also used to study the interactions of these drugs by docking the ligands into HCV active site, which revealed the likely bioactive conformations. This study showed extensive interactions between the 4-hydroxyamino α-pyranone carboxamide analogues and the active sites of HCV(residues TYR466, GLN384, TYR383 and ASP335). The design of potent new inhibitors of HCV can get useful insights from these results.

关键词： 3D-QSAR 4-hydroxyamino a-pyranone carboxamide analogues topomer CoMFA molecule design molecular docking

Topomer CoMFA, HQSAR Studies and Molecular Docking of 2,5-Diketopiperazine Derivatives as Oxytocin Inhibitors

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Chinese Journal of Structural Chemistry 2020年第8期39卷 1385-1394,1357页

作者： TONG Jian-Bo FENG Yi WANG Tian-Hao wu lu-yang College of Chemistry and Chemical Engineering Shaanxi University of Science and TechnologyXi'an 710021China Shaanxi Key Laboratory of Chemical Additives for Industry Xi'an 710021China

Topomer comparative molecular field analysis(Topomer Co MFA)and holographic quantitative structure-activity relationship(HQSAR)for 1302,5-diketopiperazine derivatives were used to build a three-dimensional quantitative structure-activity relationship(3D-QSAR)*** results show that the models have high predictive *** Topomer CoMFA,the cross-validated q^2 value is 0.710 and the non-cross-validated r^2 value is *** most effective HQSAR model shows that the cross-validation q^2 value is 0.700,the non-cross-validated r^2 value is 0.815,and the best hologram length value is 353 using connections and bonds as fragment distinctions.50 highly active 2,5-diketopiperazine derivatives were designed based on the three-dimensional equipotential map and HQSAR color code ***,the molecular docking method was also used to study the interactions of these new molecules by docking the ligands into the diketopiperazine active site,which revealed the likely bioactive *** study showed that there are extensive interactions between the new molecule and Arg156,Arg122 residues in the active site of *** results provide useful insights for the design of potent of the new 2,5-diketopiperazine derivatives.

关键词： three-dimensional quantitative structure-activity relationship Topomer CoMFA HQSAR 2,5-diketopiperazine derivatives

Frustrated superconductivity and sextetting order

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 168-176页

作者： Zhiming Pan Chen lu Fan yang Congjun wu Institute for Theoretical Sciences Westlake UniversityHangzhou 310024China New Cornerstone Science Laboratory Department of PhysicsSchool of ScienceWestlake UniversityHangzhou 310024China School of Physics Beijing Institute of TechnologyBeijing 100081China Key Laboratory for Quantum Materials of Zhejiang Province School of ScienceWestlake UniversityHangzhou 310024China Institute of Natural Sciences Westlake Institute for Advanced StudyHangzhou 310024China

The superconducting state typically favors a uniform spatial distribution akin to ***,the pair-densitywave state exhibits sign changes in the pairing order,leading to potential frustrations in phase *** propose a mechanism to the sextetting order stemming from the frustrations in the phase coherence of a pair-density-wave state,whose spatial modulation manifests a vortex-antivortex honeycomb *** classical ground state configurations are mapped to Baxter's three-coloring model,revealing a macroscopic degeneracy accompanied by extensive *** phase coherence problem intertwines the U(1)phases and the vorticity *** the resultant color and phase fluctuations suppress the pair-densitywave order,they maintain the sextetting order above the superconducting transition temperature(T_(c)).The 1/3-fractional vortex emerges as the fundamental topological defect in the sextetting *** novel mechanism of frustrated superconductivity provides an alternative explanation for the experimental observed fractional oscillations in CsV_(3)Sb_(5).

关键词： frustrated superconductivity pair density wave charge-6e order

Assessing the energy release characteristics during the middle detonation reaction stage of aluminized explosives

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Defence Technology（防务技术） 2024年第3期33卷 270-277页

作者： Kun yang Lang Chen Danyang Liu Bin Zhang Jianying lu Junying wu State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China

Afterburning behind the detonation front of an aluminized explosive releases energy on the millisecond timescale,which prolong the release of detonation energy and the energy release at different stages also shows significant ***,at present,there are few effective methods for evaluating the energy release characteristics of the middle reaction stage of such explosives,which can have a duration of tens to hundreds of *** present work demonstrates an approach to assessing the midstage of an aluminized explosive detonation based on a water push test employing a high degree of *** this method,the explosive is contained in a steel cylinder having one end closed that is installed at the bottom of a transparent water *** detonation,the gaseous products expand in one direction while forcing water ahead of *** resulting underwater shock wave and the interface between the gas phase products and the water are tracked using an ultra-high-speed framing and streak *** shock wave velocity in water and the expansion work performed by the gaseous detonation products were calculated to assess the energy release characteristics of aluminized explosives such as CL-20 and RDX in the middle stage of the detonation *** the middle stage of the detonation process of these aluminized explosives,the aluminum reaction reduced the attenuation of shock waves and increased the work performed by gas phase products.A higher aluminum content increased the energy output while the presence of oxidants slowed the energy release *** work demonstrates an effective means of evaluating the performance of aluminized explosives.

关键词： Aluminized explosive Non-ideal detonation Water push test Energy release

Top priority current path between SiC particles during ultra-high temperature flash sintering: Presence of PyC “bridges”

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Journal of Advanced Ceramics 2024年第2期13卷 255-262页

作者： Le lu Tianlong Liu Zhaofeng Chen Fei Wang Mengmeng yang Qiong wu Lixia yang Huanyong Li International Laboratory for Insulation and Energy Efficiency Materials College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 211106China State Key Laboratory of Solidification Processing School of Materials and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

Flash sintering(FS)is a novel technique for rapidly densifying silicon carbide(SiC)*** work achieved a rapid sintering of SiC ceramics by the utilization of ultra-high temperature flash sintering within 60 *** carbon(PyC)“bridges”were constructed between SiC particles through the carbonisation of phenolic resin,providing a large number of current *** incubation time of the flash sintering process was significantly reduced,and the sintering difference between the centre and the edge regions of the ceramics was minimized,with an average particle size of the centre region and edge region being 12.31 and 9.02μm,*** results showed that the porosity of the SiC ceramics after the flash sintering was reduced to 14.79% with PyC“bridges”introduced,and the Vickers hardness reached 19.62 ***“bridges”gradually evolved from amorphous eddy current carbon to oriented graphite carbon,indicating that the ultra-high temperature environment in which the sample was located during the flash sintering was successfully ***-high temperature flash sintering of SiC is expected to be applied to the local repair of matrix damage in SiC ceramic matrix composites.

关键词： silicon carbide(SiC) flash sintering(FS) pyrolytic carbon(PyC)"bridges" current path instantaneous

Simultaneous removal of Cd(Ⅱ)and As(Ⅴ)by ferrihydrite-biochar composite:Enhanced effects of As(Ⅴ)on Cd(Ⅱ)adsorption

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Journal of Environmental Sciences 2024年第5期139卷 267-280页

作者： Wenjun Zeng yang lu Jingyan Zhou Jie Zhang Yuanxiao Duan Changxun Dong Wencheng wu College of Sciences Nanjing Agricultural UniversityNanjing 210095China South China Institute of Environmental Sciences Ministry of Ecology and EnvironmentGuangzhou 510655China Guangdong Engineering&Technology Research Center for System Control of Livestock and Poultry breeding Pollution Guangzhou 510655China

The coexistence of cadmium(Cd(Ⅱ))and arsenate(As(Ⅴ))pollution has long been an environmental ***,a porous carbonaceous material with tunable functionality,has been used for the remediation of contaminated ***,it is still challenging for the dynamic quantification and mechanistic understanding of the simultaneous sequestration of multi-metals in biochar-engineered environment,especially in the presence of *** this study,ferrihydrite was coprecipitated with biochar to investigate how ferrihydritebiochar composite affects the fate of heavy metals,especially in the coexistence of Cd(Ⅱ)and As(Ⅴ).In the solution system containing both Cd(Ⅱ)and As(Ⅴ),the maximum adsorption capacities of ferrihydrite-biochar composite for Cd(Ⅱ)and As(Ⅴ)reached 82.03μmol/g and 531.53μmol/g,respectively,much higher than those of the pure biochar(26.90μmol/g for Cd(Ⅱ),and 40.24μmol/g for As(Ⅴ))and ferrihydrite(42.26μmol/g for Cd(Ⅱ),and 248.25μmol/g for As(Ⅴ)).Cd(Ⅱ)adsorption increased in the presence of As(Ⅴ),possibly due to the changes in composite surface charge in the presence of As(Ⅴ),and the increased dispersion of ferrihydrite by *** microscopic and mechanistic results showed that Cd(Ⅱ)complexed with both biochar and ferrihydrite,while As(Ⅴ)was mainly complexed by ferrihydrite in the Cd(Ⅱ)and As(Ⅴ)coexistence *** posed vital importance for the co-adsorption of Cd(Ⅱ)and As(Ⅴ).The different distribution patterns revealed by this study help to a deeper understanding of the behaviors of cations and anions in the natural environment.

关键词： Ferrihydrite Biochar Cadmium Arsenate Simultaneous sequestration Binding mechanisms