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V0405 Dra:A New Deep and Low Mass Ratio Contact Binary with Extremely Fast Decrease in the Orbital Period

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Research in Astronomy and Astrophysics 2024年第6期24卷 287-293页

作者： Chao-Yue Li lin-Qiao Jiang Jie Zheng Yi-Man Liu Xiao-Yu Long Min Sun Han-Lu Zhang Xiao-Man Tian school of science Leshan Normal UniversityLeshan 614000China Center for Applied Optics Research Leshan Normal UniversityLeshan 614000China Key Laboratory of Detection and Application of Space Effect in Southwest Sichuan Leshan 614000China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China school of aeronautics Shandong Jiaotong UniversityJinan 250000China

V0405 Dra is a W UMa-type binary *** on the TESS data,we have conducted an orbital period study and performed a light curve analysis for the *** orbital period study reveals that the O-C curve for V0405 Dra exhibits secular decrease at an extremely high rate of d P/dt=-2.71×10^(-6)day year^(-1),along with periodic variations characterized by an amplitude of A_(3)=0.0032.day and a period of P_(3)=1.413 *** orbital periodic change is possibly due to the light-travel time effect resulting from an additional third body in the system,for which we estimate a minimum mass of M_(3)=0.77M_(⊙).By employing the 2.13 version of the Wilson-Devinney(W-D)method to synthesize a light curve,we derived photometric solutions indicating that V0405 Dra is a new deep(f=68.7%)and low-mass ratio(q=0.175)contact *** fast decrease in its orbital period is likely caused by mass transfer from the more massive primary star to the less massive secondary star,or due to angular momentum *** further mass transfer and loss of angular momentum,the binary will gradually evolve into a tighter contact configuration,eventually leading to a merger into a single star,following the evolutionary paths suggested for such deep and low mass ratio contact binaries.

关键词： (stars:)binaries(including multiple):close (stars:)binaries:eclipsing stars:individual(V0405 Dra)

A Secure Device Management Scheme with Audio-Based Location Distinction in IoT

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工程与科学中的计算机建模(英文) 2024年第1期138卷 939-956页

作者： Haifeng lin Xiangfeng Liu Chen Chen Zhibo Liu Dexin Zhao Yiwen Zhang Weizhuang Li Mingsheng Cao College of Economics and Management Nanjing University of Aeronautics and AstronauticsNanjing211106China Chengdu Aircraft Industrial(Group)Co. Ltd.Chengdu610073China Academy of Military sciences of PLA Beijing100091China school of Information and Software Engineering University of Electronic Science and Technology of ChinaChengdu610054China Ningbo Web King Technology Joint Stock Co. Ltd.Ningbo315000China The Network and Data Security Key Laboratory of Sichuan Province University of Electronic Science and Technology of ChinaChengdu610054China

Identifying a device and detecting a change in its position is critical for secure devices management in the Internet of Things(IoT).In this paper,a device management system is proposed to track the devices by using audio-based location distinction *** the proposed scheme,traditional cryptographic techniques,such as symmetric encryption algorithm,RSA-based signcryption scheme,and audio-based secure transmission,are utilized to provide authentication,non-repudiation,and confidentiality in the information interaction of the management ***,an audio-based location distinction method is designed to detect the position change of the ***,the audio frequency response(AFR)of several frequency points is utilized as a device *** device signature has the features as follows.(1)Hardware Signature:different pairs of speaker and microphone have different signatures;(2.Distance Signature:in the same direction,the signatures are different at different distances;and(3)Direction Signature:at the same distance,the signatures are different in different *** on the features above,amovement detection algorithmfor device identification and location distinction is ***,a secure communication protocol is also proposed by using traditional cryptographic techniques to provide integrity,authentication,and non-repudiation in the process of information interaction between devices,Access Points(APs),and *** experiments are conducted to evaluate the performance of the proposed *** experimental results show that the proposedmethod has a good performance in accuracy and energy consumption.

关键词： Acoustic hardware fingerprinting device management IoT location distinction

Improved piezoelectric and luminescent properties in Sm-modified Bi_(0.5)Na_(0.5)TiO_(3)-BaTiO_(3) multifunctional ceramics

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Journal of Materiomics 2024年第4期10卷 803-810页

作者： Shuai Cheng Kehong Zhang Chongyang Li Boping Zhang Jianguo Chen Kang Sun Changrong zhou Jingtai Zhao Qisheng {2. Guanghui Rao Siqi Shi school of Materials science and Engineering Shanghai UniversityShanghai200444China Guangxi Key Laboratory of Information Materials&school of Materials science and Engineering Guilin University of Electronic TechnologyGuilin541004GuangxiChina school of Materials science and Engineering University of Science and Technology BeijingBeijing100083China school of Information Engineering Lanzhou University of Finance and EconomicsLanzhou730020China

The 0.93(Na_(0.5)Bi_(0.5))_(1–x)Sm_(x)TiO_(3)-0.07BaTiO_(3) multifunctional ceramics were prepared by solid-phase reaction *** phase structure,microstructure,electrical and photoluminescent properties were systematically *** increasing x,the ceramics undergoes the phase transition from rhombohedral to tetragonal with some rhombohedral distortion,along with a reduced grain size and increased relative *** the other hand,the Sm3+doping enhances the electric-field driven reversible phase transition and domain size,and reduces the domain walls,thereby contributing to improved piezoelectricity and decreased depolarization temperature(T_(d))from 91℃ to 40℃.Excellent piezoelectric properties of d_(33)=2.3 pC/N and kp=2..9% are achieved in the x=0.010 *** excitation(407 nm),the Sm^(3+)-doped ceramic exhibits bright reddish-orange fluorescence at 564,599,646 nm and 710 nm.A polarization-induced enhancement of photoluminescence is obtained in BNBT-_(x)Sm ceramics with an improved relative intensity of emission band at 646 *** results indicate that Sm^(3+)-doped BNBT ceramics show great potential in electro-optic integration and coupling device applications.

关键词： Piezoelectricity Curie temperature Phase transitions Thermal stability Photoluminescence

考虑平衡气体效应的乘波体特征线设计方法及气体模型影响

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南京航空航天大学学报 2024年第1期56卷 163-175页

作者：林鹭颖李沁严攀翁谊辉尤延铖李留刚厦门大学航空航天学院厦门361102 中国运载火箭技术研究院空间物理重点实验室北京100076

乘波体在高空高超声速飞行时,流场温度急剧升高,气体热力学性质发生改变,其气动特性与采用完全气体模型得到的结果存在差异,因此在飞行器设计中开展真实气体效应影响研究具有重要的工程价值。本文针对锥导乘波体设计提出了一种考虑平衡... 详细信息

乘波体在高空高超声速飞行时,流场温度急剧升高,气体热力学性质发生改变,其气动特性与采用完全气体模型得到的结果存在差异,因此在飞行器设计中开展真实气体效应影响研究具有重要的工程价值。本文针对锥导乘波体设计提出了一种考虑平衡气体效应的特征线方法(Method of characteristic, MOC),基于不同半锥角和不同流动捕获曲线生成了不同外形的乘波体,并使用快速估算方法估算平衡气体条件和完全气体条件下各乘波体的气动特性和几何特征参数,研究了不同气体模型对乘波体设计结果的影响。研究结果表明,高马赫数下基于平衡气体模型设计得到的乘波体升阻比、容积率和俯仰力矩系数等特性参数相比完全气体结果存在差异,并且平衡气体效应对不同外形乘波体的影响程度和影响规律不同。

关键词：高超声速平衡气体乘波体特征线方法气动特性

Dimensionless study on outlet flow characteristics of an air-driven booster

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Journal of Zhejiang university-science A(Applied Physics & Engineering) 2012年第6期13卷 481-490页

作者： yan SHI Mao-lin CAI school of automation {2. and electrical Engineering Beihang UniversityBeijing 100191China

Air-driven boosters are widely used to obtain high-pressure gas. Through analysis of the boosting process of an air-driven booster, the basic mathematical model of working processes can be set up. By selecting the appropriate reference values, the basic mathematical model is transformed to a dimensionless expression. Using MATLAB/Simulink for simulation and studying the booster experimentally, the dimensionless outlet flow characteristics of the booster were obtained and the simulation results agree well with the experimental results. Through analysis, it can be seen that the dimensionless outlet flow of the booster is mainly determined by the dimensionless input pressure of the driving chamber, the dimensionless outlet condition pressure of the booster and the dimensionless area of the piston in the driving chamber. The dimensionless average outlet flow becomes larger with an increasing dimensionless input pressure of the driving chamber, but it becomes smaller with an increase in the dimen- sionless outlet condition pressure of the booster. Especially when the dimensionless outlet condition pressure is approximately 1.4, the dimensionless average outlet flow reaches zero. With an increase in the dimensionless area of the piston in the driving chamber, the dimensionless average outlet flow increases and peaks at approximately 1.89, and after this peak, it starts to decrease. This research can be referred to in the design of air-driven boosters.

关键词： Air-driven booster Outlet flow Pneumatic system Compressed air

Recent advances in rare earth compounds for lithium-sulfur batteries

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escience 2024年第3期4卷 32-43页

作者： Bixia lin Yuanyuan Zhang Weifeng Li Junkang Huang Yong yang Siu Wing Or Zhenyu Xing Shaojun Guo school of Chemistry South China Normal UniversityGuangzhou 510006China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi'an 710072China Department of electrical Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina school of Materials science and Engineering Peking UniversityBeijing 100871China

Lithium-sulfur batteries are considered potential high-energy-density candidates to replace current lithium-ion ***,several problems remain to be solved,including low conductivity,huge volume change,and a severe shuttle effect on the cathode side,as well as inevitable lithium dendrites on the anode *** earth compounds,which play vital roles in various industries,show latent capacity as cathode hosts or interlayers to tackle the inherent problems of lithium-sulfur ***,the application of rare earth compounds in lithium-sulfur batteries has not been reviewed so far,despite they showing obvious advantages for tuning polysulfide retention and *** this mini-review,we start by introducing the concept of lithium-sulfur batteries and providing background information on rare earth-based *** the main body,we explore rare earth compounds as cathode hosts or interlayers,then discuss various types of ***,we offer an outlook on the existing challenges and possible opportunities for using rare earth compounds as cathode hosts or interlayers for lithium-sulfur batteries.

关键词： Lithium-sulfur batteriesRare earth compoundsCathode hostInterlayer

Graphene binding on black phosphorus enables high on/off ratios and mobility

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National science Review 2024年第2期11卷 188-195页

作者： Fanrong lin Zhonghan Cao Feiping Xiao Jiawei Liu Jiabin Qiao Minmin Xue Zhili Hu Ying Liu Huan Lu Zhuhua Zhang Jens Martin Qingjun Tong Wanlin Guo {2.peng Liu Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education State Key Laboratory of Mechanics and Control of Mechanical Structures and Institute for Frontier Science Nanjing University of Aeronautics and Astronautics Centre for Advanced 2. Materials National University of Singapore school of Physics and Electronics Hunan University Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and MeasurementSchool of PhysicsBeijing Institute of Technology Leibniz Institute für Kristallzüchtung

Graphene is one of the most promising candidates for integrated circuits due to its robustness against short-channel effects, inherent high carrier mobility and desired gapless nature for Ohmic contact, but it is difficult to achieve satisfactory on/off ratios even at the expense of its carrier mobility, limiting its device applications. Here, we present a strategy to realize high back-gate switching ratios in a graphene monolayer with well-maintained high mobility by forming a vertical heterostructure with a black phosphorus multi-layer. By local current annealing, strain is introduced within an established area of the graphene, which forms a reflective interface with the rest of the strain-free area and thus generates a robust off-state via local current depletion. Applying a positive back-gate voltage to the heterostructure can keep the black phosphorus insulating, while a negative back-gate voltage changes the black phosphorus to be conductive because of hole accumulation. Then, a parallel channel is activated within the strain-free graphene area by edge-contacted electrodes, thereby largely inheriting the intrinsic carrier mobility of graphene in the on-state. As a result, the device can provide an on/off voltage ratio of >10～3 as well as a mobility of ～8000 cm2.-1s-1at room temperature, meeting the low-power criterion suggested by the International Roadmap for Devices and Systems.

关键词： graphene on/off ratio mobility black phosphorus reflective interface

Characteristic of Torsional Vibration of Mill Main Drive Excited by Electromechanical Coupling

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Chinese Journal of Mechanical Engineering 2016年第1期29卷 180-187页

作者： ZHANG Yifang yan Xiaoqiang lin Qihui Institute of Mechanical Engineering University of Science and Technology Beijing school of Mechanical Engineering Anhui University of Technology

In the study of electromechanical coupling vibration of mill main drive system, the influence of electrical system on the mechanical transmission is considered generally, however the research for the mechanism of electromechanical interaction is lacked. In order to research the electromechanical coupling resonance of main drive system on the F3 mill in a plant, the cycloconverter and synchronous motor are modeled and simulated by the MTLAB/SIMUL1NK firstly, simulation result show that the current harmonic of the cycloconverter can lead to the pulsating torque of motor output. Then the natural characteristics of the mechanical drive system are calculated by ANSYS, the result show that the modal frequency contains the component which is close to the coupling vibration frequency of 42.z. According to the simulation result of the mechanical and electrical system, the closed loop feedback model including the two systems are built, and the mechanism analysis of electromechanical coupling presents that there is the interaction between the current harmonic of electrical system and the speed of the mechanical drive system. At last, by building and computing the equivalent nonlinear dynamics model of the mechanical drive system, the dynamic characteristics of system changing with the stiffness, damping coefficient and the electromagnetic torque are obtained. Such electromechanical interaction process is suggested to consider in research of mill vibration, which can induce strong coupling vibration behavior in the rolling mill drive system.

关键词： rolling mill vibration current harmonic speed oscillation electromechanical coupling vibration characteristic

Influences of characteristic parameters on starting-up process of an arcjet thruster

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Chinese Journal of aeronautics 2020年第12期33卷 3011-3017页

作者： yan shen Yinggang TONG Fuzhi WEI Zhaopu YAO Dawei HU school of Aerospace and astronautics Sun Yet-sen UniversityGuangzhou 510006China Lab of Space Propulsion Technology Beijing Institute of Control EngineeringBeijing 100094China

Arcjet thruster has been a widely used electrical propulsion technology on GEO satellites since *** its long history of technical development and commercial application,lifetime verification of an arcjet thruster is always one of the most important and expensive *** that the main life limitation of an arcjet thruster is electrode ablation and a significant share of the total ablation happens in its starting-up process,the starting-up process is studied with arc voltage *** interpretation of arc voltage signals,the transfer process of the arc root on the anode surface is identified,and?T(the duration of the arc root transfer process)is suggested to be a characteristic parameter for fast evaluation of lifetime assessment and design optimization for an arcjet *** this criterion,the influences of typical parameters on the starting-up process are established through comparison with a benchmark *** to experimental results,an increase of the gas flow will obviously reduce?T,while a smaller swirl aperture and a longer throat channel do not have a remarkable correlation with?***,with a sample of a smaller throat diameter to increase the flow velocity,a reduction of?T is ***,the modifications also affect the stability of arcjet thruster operation,which is also discussed.

关键词： Arc root Arcjet Electric propulsion Electrode ablation Starting-up process