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2nd International Conference of Mechanical system Dynamics, ICMSD 2023

作者： Pu, Jinrui Wang, Qingtao Liu, Zhendong Cai, Xiaoshuang Liu, Xiong School of Science Nanjing University of Science and Technology Nanjing China Institute of Launch Dynamics Nanjing University of Science and Technology Nanjing China National Key Laboratory of Complex Multibody System Dynamics Nanjing University of Science and Technology Nanjing China Shanghai Aerospace Systems Engineering Institute Shanghai China

ISBN: (纸本)9789819980475

The current methods for modeling, simulating, and verifying the stage separation system of a launch vehicle are limited to specific models and cannot be universally validated. Moreover, it is a time-consuming and labor-intensive task to remodel a launch vehicle with different topologies. To address this issue, this paper proposes a solution using the software MWorks. The approach involves establishing basic component models for launch vehicles, including the first stage, second stage, thrust, and explosive bolts. These component models are then utilized to create a model library for the stage separation of a launch vehicle. By employing this library, the stage separation process of a specific launch vehicle model can be simulated and analyzed to ensure the safety of the separation under harsh conditions. This methodology offers a more efficient and flexible approach to validate the stage separation system of launch vehicles. By utilizing the established model library, the need for extensive remodeling is eliminated, saving both time and effort. The simulation results provide valuable insights into the safety and effectiveness of the stage separation process. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Launch vehicles

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design of Multi-axis Motion Control system Based on EtherCAT 17th

Design of Multi-axis Motion Control System Based on EtherCAT

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17th Annual Conference of china Electrotechnical Society, CES 2022

作者： Yuan, Lida Guan, Xiaocun Guan, Shaohua Wu, Baoqi National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan430033 China

ISBN: (纸本)9789819903566

In order to solve the problem of multi-axis high-precision position control in material transportation, I designed a set of four-axis motion control system based on PID algorithm, using three closed-loop position control and a popular real-time industrial Ethernet technology – EtherCAT technology. The study shows that the application of EtherCAT technology in multi-axis control makes high-speed and high-precision multi-axis position control possible, and the loading of two pieces of material is realized in the test. This study enriches the research on communication networks in the field of automatic loading and provides theoretical guidance for the subsequent development of automatic loading control systems. © 2023, Beijing Paike Culture Commu. Co., Ltd.

关键词： Position control

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MBSE-Based Guidance system Simulation of Launch Vehicle 2nd

MBSE-Based Guidance System Simulation of Launch Vehicle

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2nd International Conference of Mechanical system Dynamics, ICMSD 2023

作者： Ma, Guowei Wang, Qingtao Zhang, Wenfeng Yu, Rendong Liu, Xiong School of Science Nanjing University of Science and Technology Nanjing China Institute of Launch Dynamics Nanjing University of Science and Technology Nanjing China National Key Laboratory of Complex Multibody System Dynamics Nanjing University of Science and Technology Nanjing China Shanghai Aerospace Systems Engineering Institute Shanghai China

ISBN: (纸本)9789819980475

In the traditional development process of the launch vehicle guidance system, the system is designed repeatedly in the earlier stage and the verification of the system is conducted in the later stage. This development mode may cause some problems, such as low design efficiency and high cost. In order to improve the shortcomings of the traditional development process, in this paper the MBSE (Model Based system Engineering) method is introduced in the design phase of the launch vehicle guidance system, and the MBSE-based design model is used to carry out system verification in real time. The application of this method greatly improves the design efficiency of the launch vehicle guidance system. The MBSE-based simulation model of the launch vehicle guidance system is established, the system perturbation guidance simulation is carried out, and the result is compared with the standard design trajectory to verify the correctness of the guidance system designed based on MBSE. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Launch vehicles

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DYNAMIC PRECISION EVALUATION OF COMPENSATED ION-CHAMBERS FOR reactor POWER MONITORING 29

DYNAMIC PRECISION EVALUATION OF COMPENSATED ION-CHAMBERS FOR...

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2022 29th International Conference on Nuclear Engineering, ICONE 2022

作者： Huang, Qichang Liu, Mingxing Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China A College of Computer Sichuan University Chengdu China

ISBN: (纸本)9780791886373

During reactor power monitoring, compensated ion-chambers (CICs) are assembled by two similar gas-filled detectors. The gamma compensation of CICs is essential for detecting precision of thermal neutrons, and requires a pairs of fully matched voltages. Descriptions of detecting precision include current formation model, in which applied voltages and radiation strength act in the process of collecting charged particles. However, the model of CICs are seldom applied in design work to evaluate the monitoring precision. Here we show that imbalance degree of collecting charged particles leads to mismatch of saturation currents depending on difference of recombination and diffusion in each sub-chambers. We analyzed a coaxial type compensated ion-chamber (DL-126), and found that applied voltages and radiation strength have significant impact for ion recombination and electron diffusion. For increasing precision of CICs, this result suggests a dynamic way to evaluate the output deviation using radiation strength. Furthermore, we found the compensation factor of two sub-chambers is only related to the applied voltages and remain unchanged in various radiation. Our results demonstrate how collecting regulars of charged particles are likely to function in setting applied voltages, calculating the charge loss as well as quantifying the saturation currents. We anticipate our analysis to be a starting point for revising detection precision of compensated ion-chambers. For example, evaluating the neutron fluence in the reactor shutdown and restart process, including monitoring task after accident. Furthermore, dynamic precision evaluation of these detectors is a major target of prognostics and health management for Nuclear Instrument. Copyright © 2022 by ASME.

关键词： Ions

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Structures and energetics of semicoherent interfaces of precipitates in hcp/bcc systems:A molecular dynamics study

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Journal of Materials science & technology 2021年第8期67卷 50-60页

作者： Jin-Yu Zhang Fu-Zhi Dai Zhi-Peng Sun Wen-Zheng Zhang Key Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Science and Technology of Advanced Functional Composite Laboratory Aerospace Research Institute of Materials&Processing TechnologyBeijing 100076China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610041China

α/β(hcp/bcc)interfaces are of great importance in the microstructure development and the mechanical properties of titanium and zirconium *** work contributes to the study of interface energetics and interfacial structures of the precipitate in the hcp/bcc system based on a simulation study using molecular statics(MS)and molecular dynamics(MD).The input orientation relationship(OR)was calculated based on the O-line *** on the energy of the interfaces containing the invariant line(IL),two preferred facets were determined by the Wulff construction,which explained the observed orientations of the habit plane(HP)and the side facet(SF).The deviation of the observed precipitate morphology from the equilibrium shape was discussed in terms of interface *** structures of the interfaces surrounding a three-dimensional(3 D)precipitate,including the preferred facets and the end face,were obtained at the atomic *** simulated dislocation structures and atomic structures in these interfaces are in good agreement with those of the experimental observations for Ti-Cr alloys.A method was suggested for modifying the O-cell structure with the guidance of the relaxed structure,yielding consistency between the calculated dislocation structure based on the generalized O-element approach and the simulation results.

关键词： Interface Misfit dislocation Precipitate

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Vibration Reduction of Tracked Vehicle-Seat-Occupant system Based on Two-Stage Magnetorheological Suspension 2nd

Vibration Reduction of Tracked Vehicle-Seat-Occupant System ...

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2nd International Conference of Mechanical system Dynamics, ICMSD 2023

作者： Jiang, Rilang Rui, Xiaoting Zhu, Wei Wei, Min Zhu, Hongtao Gu, Lilin Institute of Launch Dynamics Nanjing University of Science and Technology 200 Xiaolingwei Nanjing210094 China National Key Laboratory of Complex Multibody System Dynamics Nanjing University of Science and Technology 200 Xiaolingwei Nanjing210094 China

ISBN: (纸本)9789819980475

The purpose of this work is to verify the superiority of the two-stage magnetorheological (MR) suspension in improving the occupant comfort of tracked armored vehicles. A vibration reduction scheme for the two-stage MR suspension is proposed, which consists of the MR vehicle suspension and MR seat suspension. This two-stage MR suspension design achieves outstanding vibration reduction performance on tracked vehicles, significantly reducing the dynamic responses of vehicle occupants. The dynamic model of the tracked vehicle-seat-occupant system is established based on the transfer matrix method for multibody systems (MSTMM), and through dynamic simulations combined with the Skyhook control strategy, the superior performance of the two-stage MR suspension is demonstrated. Compared to passive suspension system, the two-stage MR suspension exhibits a performance improvement of over 40%, effectively proving its superiority in vibration reduction for tracked vehicles. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Automobile suspensions

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Dual-Polarized Wideband Wide-Beam Millimeter-Wave Magneto-Electric Dipole Antenna

Dual-Polarized Wideband Wide-Beam Millimeter-Wave Magneto-El...

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2023 Cross Strait Radio science and Wireless technology Conference, CSRSWTC 2023

作者： Gou, Linglong Ma, Jing Shi, Bin Zhu, Zhongbo Peng, Lin Guilin University of Electronic Technology Key Laboratory of Microwave and Optical Wave Application Technology Guangxi Guilin541004 China Beijing Simulation Center The Science and Technology on Special System Simulation Laboratory Beijing100854 China The National Key Laboratory of Science and Technology on Space Microwave Xi'an710100 China

ISBN: (纸本)9798350358971

In this manuscript, a dual-polarized wideband wide beamwidth magneto-electric (ME) dipole antenna for millimeter-wave mobile communication is proposed. As can be seen from the simulation results, this design exhibits excellent performance. Owing to the mutual resonances of the magnetic dipole and the electric dipole, large bandwidths of 64.8% and 59% (18.4 GHz-33 GHz and 17.29 GHz-33.9 GHz) are obtained for the two polarizations, respectively. The isolation between the two ports is greater than 25 dB. By loading metal vias, the antenna's beamwidth is widened to more than 100° through the whole operating band. The antenna size is 5mm×5 mm ×1.72 mm, and this compact structure is quite suitable for using in beam scanning antennas. © 2023 IEEE.

关键词： dual-polarization millimeter-wave (mm-wave) wideband

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Active Flow Control of Hydrodynamic Characteristics around a Square Cylinder with Symmetric Synthetic Jets 34th

Active Flow Control of Hydrodynamic Characteristics around a...

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34th International Ocean and Polar Engineering Conference, ISOPE 2024

作者： Ding, Hao Liu, Mingyue Zhou, Jihui Zhu, Shenglong State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai China SJTU YaZhou Bay Institude of Deepsea Science and Technology Sanya China System Design Institute of Hubei Aerospace Technology Academy Wuhan China

ISBN: (纸本)9781880653784

To explore the active control method of the square cylinder wake field modification, a self-developed piston-driven synthetic jet actuator is used to generate periodic blowing and suction jets through the slits to affect the external flow field. The flow characteristics around the square cylinder controlled by synthetic jet is experimentally investigated with the force measuring system and Particle Image Velocity (PIV) technique. The statistical fluid forces, the frequency characteristics, and the time-averaged flow flied are compared with different control parameters, i.e. jet exit angle (β), the momentum coefficient (Cμ), and the excitation frequency (f*). With control, dramatic reduction in CLrms (up to 61%) is attained and the corresponding value of CD is 12% at β =45°. Narrower and longer backflow region represents a decrease in flow-induced forces. © 2024 by the International Society of Offshore and Polar Engineers (ISOPE).

关键词： Jets

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NUMERICAL ANALYSIS ON FLOW AND HEAT TRANSFER CHARACTERISTICS OF LBE IN NARROW RECTANGULAR CHANNELS 30

NUMERICAL ANALYSIS ON FLOW AND HEAT TRANSFER CHARACTERISTICS...

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30th International Conference on Nuclear Engineering, ICONE 2023

作者： Jiang, Yanming Li, Xiaochang Tian, Ruifeng Lu, Chuan Song, Zhiguang College of Nuclear Science and Technology Harbin Engineering University Harbin China Heilongjiang Provincial Key Laboratory of Nuclear Power Plant Performance and Equipment Harbin Engineering University Harbin China College of Aerospace and Civil Engineering Harbin Engineering University Harbin China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9784888982566

The lead-bismuth eutectic alloy (LBE) is a candidate coolant for the generation IV liquid metal reactors, and the plate-type fuel assemblies are widely used in the small or research reactors. However, the turbulent heat transfer behaviors of low Prandtl number LBE are quite different from that of ordinary fluids due to its violation in Reynolds analogy, and its flow and heat transfer process in narrow rectangular channels need to be studied with new methods. For this purpose, the authors conduct numerical simulation and analysis of turbulent flow of the LBE in narrow rectangular channel and compare the numerical simulation results with correlation proposed for liquid metal, moreover, the applicability of different near wall treatment methods, turbulence models and turbulent Prandtl number (Prt) models is compared. The focus of the analysis is on the impacts of the collocation of various models on the Nusselt number, the flow redistribution phenomena, as well as the difference in flow and heat transfer capacity in channels. According to the results, the suggested turbulence model and Prt model for different Peclet (Pe) numbers are recommended, besides the flow redistribution phenomenon in the three channels fuel assembly can be ignored, only slightly affects the flow and heat transfer in the narrow rectangular inlet region. © 2023 by JSME.

关键词： Turbulence models

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DarkSAM: Fooling Segment Anything Model to Segment Nothing 38

DarkSAM: Fooling Segment Anything Model to Segment Nothing

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38th Conference on Neural Information Processing systems, NeurIPS 2024

作者： Zhou, Ziqi Song, Yufei Li, Minghui Hu, Shengshan Wang, Xianlong Zhang, Leo Yu Yao, Dezhong Jin, Hai National Engineering Research Center for Big Data Technology and System China Services Computing Technology and System Lab China Cluster and Grid Computing Lab China Hubei Engineering Research Center on Big Data Security China Hubei Key Laboratory of Distributed System Security China School of Computer Science and Technology Huazhong University of Science and Technology China School of Cyber Science and Engineering Huazhong University of Science and Technology China School of Software Engineering Huazhong University of Science and Technology China School of Information and Communication Technology Griffith University Australia

Segment Anything Model (SAM) has recently gained much attention for its outstanding generalization to unseen data and tasks. Despite its promising prospect, the vulnerabilities of SAM, especially to universal adversarial perturbation (UAP) have not been thoroughly investigated yet. In this paper, we propose DarkSAM, the first prompt-free universal attack framework against SAM, including a semantic decoupling-based spatial attack and a texture distortion-based frequency attack. We first divide the output of SAM into foreground and background. Then, we design a shadow target strategy to obtain the semantic blueprint of the image as the attack target. DarkSAM is dedicated to fooling SAM by extracting and destroying crucial object features from images in both spatial and frequency domains. In the spatial domain, we disrupt the semantics of both the foreground and background in the image to confuse SAM. In the frequency domain, we further enhance the attack effectiveness by distorting the high-frequency components (i.e., texture information) of the image. Consequently, with a single UAP, DarkSAM renders SAM incapable of segmenting objects across diverse images with varying prompts. Experimental results on four datasets for SAM and its two variant models demonstrate the powerful attack capability and transferability of DarkSAM. Our codes are available at: https://***/CGCL-codes/DarkSAM. © 2024 Neural information processing systems foundation. All rights reserved.

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