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Journal of Rock Mechanics and Geotechnical engineering 2024年第7期16卷 2732-2748页

作者： Javad Ghorbani Arooran Sounthararajah Troyee Tanu Dutta Jayantha Kodikara ARC Smart Pavements Hub Dept.of Civil EngineeringMonash UniversityVIC3800Australia

This study introduces an advanced finite element model for the light weight deflectometer(LWD),which integrates contact mechanics with fully coupled *** simulating LWD tests on granular soils at various saturation levels,the model accurately reflects the dependence of the LWD modulus on dry density,water content,and effective *** model addresses and overcomes the limitations of previous finite element models for this specific ***,this research presents the first experimentally validated fully coupled contact impact ***,the research provides a comparative assessment of elastoplastic and nonlinear elastic models and contrasts an enriched node-tosegment method(developed in this study)with the more precise mortar technique for contact *** comparisons reveal unique advantages and challenges for each ***,the study underscores the importance of careful application of the LWD modulus,emphasising the need for sophisticated tools to interpret soil behaviour accurately.

关键词： Granular soils Plasticity Finite element analysis Contact mechanics Modulus Degree of saturation

Perturbed low-thrust geostationary orbit transfer guidance via polynomial costate estimation

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Chinese Journal of Aeronautics 2024年第3期37卷 181-193页

作者： Zhao LI Hengnian LI Fanghua JIANG Junfeng LI State Key Laboratory of astronautic Dynamics Xi’an Satellite Control CenterXi’an 710043China School of Aerospace engineering Tsinghua UniversityBeijing 100084China

This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary *** Earth’s oblateness perturbation and shadow are taken into *** is difficult for a Lyapunov-based or trajectory-tracking guidance method to possess multiple characteristics at the same time,including high guidance optimality,robustness,and onboard computational *** this work,a concise relationship between the minimum-time transfer problem with orbital averaging and its optimal solution is identified,which reveals that the five averaged initial costates that dominate the optimal thrust direction can be approximately determined by only four initial modified equinoctial orbit elements after a coordinate *** on this relationship,the optimal averaged trajectories constituting the training dataset are randomly generated around a nominal averaged *** polynomial regression models are trained on the training dataset and are regarded as the costate *** the transfer,the spacecraft can obtain the real-time approximate optimal thrust direction by combining the costate estimations provided by the estimators with the current state at any ***,all these computations onboard are *** simulation results show that the proposed guidance scheme possesses extremely high guidance optimality,robustness,and onboard computational efficiency.

关键词： Low thrust Orbital transfer Trajectory optimization Guidance Indirect method Orbital averaging Machine learning Geostationary satellites

Optimal therapy for HIV infection containment and virions inhibition

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Infectious Disease Modelling 2024年第1期9卷 10-26页

作者： Paolo Di Giamberardino Daniela Iacoviello Muhammad Zubair dept.of Computer Control and Management EngineeringSapienzaUniversity of RomeVia Ariosto 2500185RomeItaly

Prevention and early diagnosis are the best and most effective ways for defeating *** is still no vaccine,but treatments with antiretroviral drugs are now available which,in many cases,allow the infection to become ***,research has highlighted side effects of these drugs and the fact that a flare-up of the infection occurs if the therapy is *** recent years,the presence of virus reserves located in various parts of the body,including the brain,has been *** possibility of controlling the infection of healthy cells and of interrupting the proliferation of virions inside the brain has been studied,proposing optimal control strategies.

关键词： Epidemic modeling HIV-AIDS Optimal control

Study of Axial Force and Deformation of Double-System Composite Guideway Considering Slip and Uplift Effects

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Journal of Traffic and Transportation engineering(English Edition) 2024年

作者： Zhengwei Bai Eryu Zhu Wenchao Cai Honghe Jian Jiacheng Li dept.of Bridge， Beijing Jiaotong University

This study fills the gap in the theoretical research of the interface deformation of the Double-System Composite Guideway (DSCG) in multi-system monorail transportation. By integrating the vertical lifting theory of the combined interface with the three-way deformation theory， this paper established a methodology for the interface analysis of the DSCG. Subsequently， a finite element analysis model of the DSCG was developed using a modified parameter model， enabling the study and summary of the deformation laws of the interface under different vehicle loads. The results show that the modified finite element model reduces the axial force and deformation by approximately 10%. Under vehicle loading， the transverse deformation of the combined interface accounts for 65.26% of the transverse deformation at the bottom of the concrete guideway， the vertical deformation accounts for 27.1%， and the longitudinal deformation accounts for 74.55%. Under the influence of a level 10 vehicle load， the deformation of the combined interface in three directions is uniformly distributed， indicating that the connectors remain in the elastic stage. The conclusions of this paper not only lay a foundation for the research of the DSCG guideway but also promote the development of a multi-standard monorail transit system.

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Numerical analysis of the return flow solar air heater(RF-SAH)with assimilation of V-type artificial roughness

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Energy and Built Environment 2024年第2期5卷 185-193页

作者： Prashant Raturi Hemlata Deolal Sanjeev Kimothi Department of Mechanical engineering Swami Rama Himalayan University Dehradun248140India Department of Mechanical engineering DIT UniversityDehradun248001India Division of Research&Innovation Dept.of PhysicsUttaranchal University248007India

A novel design of Return Flow Solar Air Heater(RFSAH)with different arrangements of baffles especially V-Type Artificial roughness is simulated and numerically analyzed with energy balance *** enhance the effectiveness of baffles,numerous studies have been *** performance of the RFSAH is studied in terms of thermal efficiency,thermo-hydraulic efficiency,and optimization of baffle *** Thermal efficiency and thermo-hydraulic efficiency are found in RFSAH with baffle on both sides of the absorber plate and mass flow rate above 0.2kg/*** analysis of the influencing parameters is carried out and reported the best performance of the system on selective geometrical parameters(ψ=0.7,β=20%,e/H=1,p/e=0.8,α=60°).The results obtained from the present model are validated with the published experimental results and have been found in quite reasonable agreement with an average error of 16.45%.Thermal and Thermohydraulic efficiency of RFSAH with a baffle on both sides of the absorber plate is maximum among baffles below,above,and on both sides of the absorber *** is observed that the thermal efficiency of RFSAH is greater than *** proposed optimum baffles roughness is suggested to increase the air upholding time period for more efficient output.

关键词： Numerical analysis Energy Balance Equations Thermal Efficiency Return flow solar air heater V-baffles

Effect of Multiple Models of Closed-loop Transfer Functions on Inter-harmonic Oscillation Characteristics of Grid-connected PMSG

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CSEE Journal of Power and Energy Systems 2024年第5期10卷 1955-1964页

作者： Jingyi Li Jianjun Yang Xiaorong Xie Haozhi Li Ke Wang Zhaohui Shi Key Laboratory of Far-shore Wind Power Technology of Zhejiang Province Huadong Engineering Corporation LimitedPower ChinaHangzhou 310014China. State Key Lab of Control and Simulation of Power Systems and Generation Equipment(dept.of Electrical engineering Tsinghua University)Beijing 100084China.

Establishing a suitable closed-loop transfer function model for the grid-connected PMSG system is the key basis in performing inter-harmonic characteristics *** closed-loop transfer functions can be constructed when different components of the converter controller are taken into ***,the effect of different components of the converter controller on inter-harmonic stability analysis is not *** this paper,the complete transfer function,considering different loops,is first *** on the complete closed-loop transfer function,the DC-link,PLL and voltage forward-feed are removed step by step to derive different closed-loop transfer *** inter-harmonic related poles of different closed-loop transfer functions are further calculated to analyze the effect of closedloop transfer functions on inter-harmonic characteristics ***,by performing time domain simulation,the correctness of the theoretical analysis results is *** results show that under the conditions of a weak AC system,each loop of the converter control system will reduce the stability of the interharmonic in the sub-synchronous frequency range and influence the inter-harmonic oscillation *** transfer function needs to consider the influence of each loop to accurately calculate the inter-harmonic stability of the system.

关键词： Closed-loop transfer function converter controller inter-harmonic characteristics PMSG

Fast measurement and prediction method for electromagnetic susceptibility of receiver

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Journal of Systems engineering and Electronics 2024年第2期35卷 275-285页

作者： CHEN Yan LU Zhonghao LIU Yunxia State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and TechnologyNational University of Defense TechnologyChangsha 410073China State Key Laboratory of astronautic Dynamics Xi’an 710043China

Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional two-tone ***,two signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent ***,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the power domain,which provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the *** experiment performed on a radar receiver confirms the reliability of the method proposed in this *** shows that the interference of each harmonic frequency and each order to the receiver can be identified and predicted with the sensitivity *** on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized.

关键词： electromagnetic susceptibility(EMS) receiver dualchannel multi-frequency nonlinear response frequency domain power domain

Second-order divided difference filter for vision-based relative navigation

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Journal of Harbin Institute of Technology(New Series) 2011年第3期18卷 16-20页

作者：王小刚崔乃刚郭继峰 dept.of astronautic engineering Harbin Institute of Technology

A second-order divided difference filter (SDDF) is derived for integrating line of sight measurement from vision sensor with acceleration and angular rate measurements of the follower to estimate the precise relative position,velocity and attitude of two unmanned aerial vehicles (UAVs).The second-order divided difference filter which makes use of multidimensional interpolation formulations to approximate the nonlinear transformations could achieve more accurate estimation and faster convergence from inaccurate initial conditions than standard extended Kalman *** filter formulation is based on relative motion *** global attitude parameterization is given by quarternion,while a generalized three-dimensional attitude representation is used to define the local attitude *** results are shown to compare the performance of the second-order divided difference filter with a standard extended Kalman filter approach.

关键词： relative navigation second-order divided difference filter vision sensor unmanned aerial vehicle formation flight

Ultra-high spatio-temporal resolution imaging with parallel acquisition-readout structured illumination microscopy(PAR-SIM)

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Light(Science & Applications) 2024年第6期13卷 1140-1158页

作者： Xinzhu Xu Wenyi Wang Liang Qiao Yunzhe Fu Xichuan Ge Kun Zhao Karl Zhanghao Meiling Guan Xin Chen Meiqi Li Dayong Jin Peng Xi Department of Biomedical engineering College of Future TechnologyPeking UniversityBeijing100871China Wallace H.Coulter dept.of Biomedical engineering Georgia Institute of Technology and Emory UniversityAtlanta30332GAUSA National Biomedical Imaging Center Peking UniversityBeijing100871China Department of Biomedical engineering College of EngineeringSouthern University of Science and TechnologyShenzhen518055GuangdongChina Airy Technologies Co. Ltd.Beijing100086China Eastern Institute for Advanced Study Eastern Institute of TechnologyNingboZhejiang315200China School of Life Science Peking UniversityBeijing100871China Institute for Biomedical Materials and Devices(IBMD) Faculty of ScienceUniversity of Technology SydneySydneyNSW2007Australia

Structured illumination microscopy(SIM)has emerged as a promising super-resolution fluorescence imaging technique,offering diverse configurations and computational strategies to mitigate phototoxicity during real-time imaging of biological *** efforts to enhance system frame rates have concentrated on processing algorithms,like rolling reconstruction or reduced frame reconstruction,or on investments in costly sCMOS cameras with accelerated row readout *** this article,we introduce an approach to elevate SIM frame rates and region of interest(ROI)coverage at the hardware level,without necessitating an upsurge in camera expenses or intricate ***,parallel acquisition-readout SIM(PAR-SIM)achieves the highest imaging speed for fluorescence imaging at currently available detector *** using the full frame-width of the detector through synchronizing the pattern generation and image exposure-readout process,we have achieved a fundamentally stupendous information spatial-temporal flux of 132.9 MPixels·s^(−1),9.6-fold that of the latest techniques,with the lowest SNR of−2.11 dB and 100 nm ***-SIM demonstrates its proficiency in successfully reconstructing diverse cellular organelles in dual excitations,even under conditions of low signal due to ultra-short exposure ***,mitochondrial dynamic tubulation and ongoing membrane fusion processes have been captured in live COS-7 cell,recorded with PAR-SIM at an impressive 408 *** posit that this novel parallel exposure-readout mode not only augments SIM pattern modulation for superior frame rates but also holds the potential to benefit other complex imaging systems with a strategic controlling approach.

关键词： hardware illumination resolution

Pressure Wave and Fluid Velocity in a Bend-Mode Inkjet Nozzle with Double PZT Actuators

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Journal of Thermal Science 2013年第1期22卷 29-35页

作者： Sungu Kim Jaeyong Sung Myeong Ho Lee Graduate School Dept.of Mechanical EngineeringSeoulTech dept.of Mechanical and Automotive engineering SeoulTech

A new concept of bend-mode inkjet nozzle with double PZT (lead zirconate titanate) actuators has been designed and fabricated in the present study. Then the pressure wave and fluid velocity at the nozzle exit have been investigated. The complex pressure behavior inside the channel was solved numerically based on the narrow channel acoustic theory. The two PZTs attached to a rectangular channel were actuated sequentially by setting the waveforms of each PZT to be center-aligned with various pulse widths. As a result, the double PZT actuation is superior to the single PZT actuation in view of strong momentum force and fast dissipation of residual pressure. The maximum fluid velocity at the nozzle exit is observed when the respective pulse widths equal to their optimum pulse widths. The numerical results are supported by the experimental results with the fabricated inkjet device by measuring the speed of meniscus just out of the nozzle.

关键词： double PZT actuators inkjet nozzle narrow channel theory pressure wave sequential actuation