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Defence technology（防务技术） 2024年第4期34卷 328-338页

作者： Yangtian Liu Xiaopeng Yan Qiang Liu Tai An Jian Dai science and technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China China Research and Development academy of machinery Equipment Beijing 100089China

The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference ***,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio *** solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is ***,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)***,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for *** DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical *** trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.

关键词： Automatic modulation recognition Adaptive denoising Data rearrangement and the 2D FFT(DR2D) Radio fuze

Research on the quasi-isentropic driving model of aluminized explosives in the detonation wave propagation direction

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Defence technology（防务技术） 2024年第2期32卷 596-618页

作者： Hongfu Wang Yan Liu Fan Bai Chao He Yingliang Xu Qiang Zhou Chuan Xiao Fenglei Huang State Key Laboratory of Explosion science and technology Beijing Institute of TechnologyBeijing100081China China Research and Development academy of machinery Equipment Beijing100089China Beijing Institute of technology Chongqing Innovation Center Chongqing401120China

Taking CL-20(Hexanitrohexaazaisowurtzitane)-based aluminized explosives with high gurney energy as the research object, this research experimentally investigates the work capability of different aluminized explosive formulations when driving metal flyer plates in the denotation wave propagation *** research results showed that the formulations with 43 μm aluminum(Al) powder particles(The particle sizes of Al powder were in the range of 2~43 μm) exhibited the optimal performance in driving flyer plates along the denotation wave propagation direction. Compared to the formulations with Al powder 13 μm, the formulations with Al powder 2 μm delivered better performance in accelerating metal flyer plates in the early stage, which, however, turned to be poor in the later stage. The CL-20-based explosives containing 25% Al far under-performed those containing 15% Al. Based on the proposed quasi-isentropic hypothesis, relevant isentropy theories, and the functional relationship between detonation parameters and entropy as well as Al reaction degree, the characteristic lines of aluminized explosives in accelerating flyer plates were theoretically studied, a quasi-isentropic theoretical model for the aluminized explosive driving the flyer plate was built and the calculation methods for the variations of flyer plate velocity, Al reaction degree, and detonation product parameters with time and axial positions were developed. The theoretical model built is verified by the experimental results of the CL-20-based aluminized explosive driving flyer plate. It was found that the model built could accurately calculate the variations of flyer plate velocity and Al reaction degree over time. In addition, how physical parameters including detonation product pressure and temperature varied with time and axial positions was identified. The action time of the positive pressure after the detonation of aluminized explosives was found prolonged and the downtrend of the temperature was

关键词： Aluminized explosive Flyer plate experiment Quasi-isentropic theoretical model Al reaction Driving characteristics

High-speed penetration of ogive-nose projectiles into thick concrete targets:Tests and a projectile nose evolution model

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Defence technology（防务技术） 2024年第2期32卷 553-571页

作者： Xu Li Yan Liu Junbo Yan Zhenqing Shi Hongfu Wang Yingliang Xu Fenglei Huang State Key Laboratory of Explosion science and technology Beijing Institute of TechnologyBeijing100081China Beijing Institute of technology Chongqing Innovation Center Chongqing401120China China Research and Development academy of machinery Equipment Beijing100089China

The majority of the projectiles used in the hypersonic penetration study are solid flat-nosed cylindrical projectiles with a diameter of less than 20 *** study aims to fill the gap in the experimental and analytical study of the evolution of the nose shape of larger hollow projectiles under hypersonic *** the hypersonic penetration test,eight ogive-nose AerMet100 steel projectiles with a diameter of 40 mm were launched to hit concrete targets with impact velocities that ranged from 1351 to 1877 m/*** erosion of the projectiles was observed during high-speed penetration of heterogeneous targets,and apparent localized mushrooming occurred in the front nose of recovered *** examining the damage to projectiles,a linear relationship was found between the relative length reduction rate and the initial kinetic energy of projectiles in different penetration ***,microscopic analysis revealed the forming mechanism of the localized mushrooming phenomenon for eroding penetration,i.e.,material spall erosion abrasion mechanism,material flow and redistribution abrasion mechanism and localized radial upsetting deformation ***,a model of highspeed penetration that included erosion was established on the basis of a model of the evolution of the projectile nose that considers radial upsetting;the model was validated by test data from the literature and the present *** upon the impact velocity,v0,the projectile nose may behave as undistorted,radially distorted or *** to the effects of abrasion of the projectile and enhancement of radial upsetting on the duration and amplitude of the secondary rising segment in the pulse shape of projectile deceleration,the predicted DOP had an upper limit.

关键词： High-speed penetration Concrete target Erosion Projectile nose evolution model

Design and optimization of fluid lubricated bearings operated with extreme working performances——a comprehensive review

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International Journal of Extreme Manufacturing 2024年第2期6卷 325-376页

作者： Guohua Zhang Ming Huang Gangli Chen Jiasheng Li Yang Liu Jianguo He Yueqing Zheng Siwei Tang Hailong Cui Institute of machinery Manufacturing technology China Academy of Engineering PhysicsMianyangSichuan 621999People’s Republic of China

Fluid lubricated bearings have been widely adopted as support components for high-end equipment in metrology,semiconductor devices,aviation,strategic defense,ultraprecision manufacturing,medical treatment,and power *** all these applications,the equipment must deliver extreme working performances such as ultraprecise movement,ultrahigh rotation speed,ultraheavy bearing loads,ultrahigh environmental temperatures,strong radiation resistance,and high vacuum operation,which have challenged the design and optimization of reliable fluid lubricated *** of any related bottlenecks will promote the development course of high-end *** promote the advancement of high-end equipment,this paper reviews the design and optimization of fluid lubricated bearings operated at typical extreme working performances,targeting the realization of extreme working performances,current challenges and solutions,underlying deficiencies,and promising developmental *** paper can guide the selection of suitable fluid lubricated bearings and optimize their structures to meet their required working performances.

关键词： fluid lubricated bearings structural design performance optimization extreme working performances

Truly optimal semi-active damping to control free vibration of a single degree of freedom system

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 142-145页

作者： Viet Duc La Ngoc Tuan Nguyen Institute of Mechanics Vietnam Academy of Science and TechnologyHanoi 10000Vietnam Graduate University of science and technology Vietnam Academy of Science and TechnologyHanoi 10000Vietnam

This paper studies a single degree of freedom system under free vibration and controlled by a general semiactive damping.A general integral of squared error is considered as the performance index.A one-time switching damping controller is proposed and *** pontryagin maximum principle is used to prove that no other form of semi-active damping can provide the better performance than the proposed one-time switching damping.

关键词： Analytical optimization Quadratic integral Lyapunov equation Pontryagin maximum principle

Study on thermal decomposition kinetics of azobenzene-4,4′-dicarboxylic acid by using compensation parameter method and nonlinear fitting evaluation

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Chinese Journal of Chemical Engineering 2024年第6期70卷 269-279页

作者： Shuyi Shen Song Guo Sining Chen Jinhua Zhao Nanjing University of science&technology Nanjing 210094China China academy of Safety science and technology Beijing 100012China

Recently,azobenzene-4,4'-dicarboxylic acid(ADCA)has been produced gradually for use as an organic synthesis or pharmaceutical intermediate due to its eminent *** large quantities put into application in the future,the thermal stability of this substance during storage,transportation,and use will become quite ***,in this work,the thermal decomposition behavior,thermal decomposition kinetics,and thermal hazard of ADCA were *** were conducted by using a SENSYS evo DSC device.A combination of differential iso-conversion method,compensation parameter method,and nonlinear fitting evaluation were also used to analyze thermal kinetics and mechanism of ADCA *** results show that when conversion rate α increases,the activation energies of ADCA's first and main decomposition peaks *** amount of heat released during decomposition varies between 182.46 and 231.16 J·g^(-1).The proposed kinetic equation is based on the Avrami-Erofeev model,which is consistent with the decomposition *** the Frank-Kamenetskii model,a calculated self-accelerating decomposition temperature of 287.0℃is obtained.

关键词： Azobenzene-4,4′-dicarboxylic acid Thermal decomposition behavior Kinetic mechanism Thermal hazard evaluation Compensation parameter effect

Effect of Three-High Rotary Piercing Process on Microstructure,Texture and Mechanical Properties of Magnesium Alloy Seamless Tube

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 953-968页

作者： Xiaofeng Ding Zehao Wu Tong Li Jianxun Chen Yuanhua Shuang Baosheng Liu Heavy machinery Engineering Research Center of Education Ministry Taiyuan University of Science and TechnologyTaiyuan030024China College of Materials science and Engineering Taiyuan University of Science and TechnologyTaiyuan030024China

Mg alloy seamless tubes(MASTs)were prepared through three-high rotary piercing process,effect of billet temperature,feed angle and plug advance on microstructure,texture and mechanical properties of tubes were *** effect on the deformation mechanism and improving mechanical properties mechanism of this process for MASTs were *** results show that the grain size could be refined to 11.3-31.1%of the initial grain size and the microstructure was more uniform due to the accumulation of *** formation of high strain gradient at the grain boundary activated the non-basal *** piercing process could change the grain orientation of as-extruded billet and eliminate the initial basal texture to produce new favorable *** the process could accelerate the continuous dynamic recrystallization *** piercing,yield strength of pierced tubes decreased by 6.7%,ultimate tensile strength(UTS)and elongation increased by 32.4 and 45%,respectively,at optimal *** plate-shapedβ_(1)-Mg_(17)Al_(12) orientation transformed from basal plates to prismatic plates,facilitating the increase in UTS and *** decrease size of nanoscale precipitates could reduce the cracking *** critical resolved shear stress ratios of pyramidal(10−11)slip and(11−22)slip to basal slip for the sample including prismatic plates both decreased compared to that including basal *** could enhance the ductility of tube ***,grain boundary sliding could contribute to a better ductility via coordinating deformation and reducing stress concentration during piercing process.

关键词： Mg alloy tube Rotary piercing Microstructure Texture Mechanical properties

Multi-objective global optimization approach predicted quasi-layered ternary TiOS crystals with promising photocatalytic properties

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Chinese Physics B 2024年第8期33卷 447-454页

作者：向依婕高思妍王春雷方海平段香梅郑益峰张越宇 Shanghai Institute of Applied Physics Chinese Academy of Sciences University of Chinese academy of sciences School of Materials science and Engineering East China University of Science and Technology College of science Shanghai University School of Physics East China University of Science and Technology School of Physical science and technology Ningbo University Wenzhou Institute University of Chinese Academy of Sciences (UCAS)

Titanium dioxide（TiO2） has attracted considerable research attentions for its promising applications in solar cells and photocatalytic ***,the intrinsic challenge lies in the relatively low energy conversion efficiency of TiO2,primarily attributed to the substantial band gaps（exceeding 3.0 eV） associated with its rutile and anatase *** multi-objective global optimization,we have identified two quasi-layered ternary Ti-O-S crystals,composed of titanium,oxygen,and *** calculations of formation energy,phonon dispersions,and thermal stability confirm the chemical,dynamical and thermal stability of these newly discovered *** the state-of-art hybrid density functional approach and many-body perturbation theory（quasiparticle GW approach and Bethe-Salpeter equation）,we calculate the optical properties of both the TiOS ***,both phases show favorable photocatalytic characteristics,featuring band gaps suitable for visible optical absorption and appropriate band alignments with water for effective charge carrier ***,ternary compound TiOS holds the potential for achieving high-efficiency photochemical conversion,showing our multi-objective global optimization provides a new approach for novel environmental and energy materials design with multicomponent compounds.

关键词： first principles calculations multi-objective global optimization photocatalysis

Kriging Model Averaging Based on Leave-One-Out Cross-Validation Method

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Journal of Systems science & Complexity 2024年第5期37卷 2132-2156页

作者： FENG Ziheng ZONG Xianpeng XIE Tianfa ZHANG Xinyu School of Mathematics Statistics and Mechanics Beijing University of Technology academy of Mathematics and Systems science Chinese Academy of Sciences

In recent years, Kriging model has gained wide popularity in various fields such as space geology, econometrics, and computer experiments. As a result, research on this model has *** this paper, the authors propose a model averaging estimation based on the best linear unbiased prediction of Kriging model and the leave-one-out cross-validation method, with consideration for the model uncertainty. The authors present a weight selection criterion for the model averaging estimation and provide two theoretical justifications for the proposed method. First, the estimated weight based on the proposed criterion is asymptotically optimal in achieving the lowest possible prediction ***, the proposed method asymptotically assigns all weights to the correctly specified models when the candidate model set includes these models. The effectiveness of the proposed method is verified through numerical analyses.

关键词： Asymptotic optimality best linear unbiased prediction cross-validation Kriging model model averaging

Multi-region calcium imaging in freely behaving mice with ultra-compact head-mounted fluorescence microscopes

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National science Review 2024年第1期11卷 161-173页

作者： Feng Xue Fei Li Ke-ming Zhang Lufeng Ding Yang Wang Xingtao Zhao Fang Xu Danke Zhang Mingzhai Sun Pak-Ming Lau Qingyuan Zhu Pengcheng Zhou Guo-Qiang Bi Department of Precision machinery and Precision Instruments University of Science and Technology of China Hefei National Laboratory for Physical sciences at the Microscale University of Science and Technology of China Interdisciplinary Center for Brain Information the Brain Cognition and Brain Disease Institute Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Faculty of Life and Health sciences Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences School of Life sciences University of Science and Technology of China Institute of Semiconductors Chinese Academy of Sciences Department of Modern Life sciences and Biotecnology Xiongan Institute of Innovation Xiongan New Area Shenzhen-Hong Kong Institute of Brain science-Shenzhen Fundamental Research Institutions Suzhou Institute for Advanced Research University of Science and Technology of China Institute of Artiflcial Intelligence Hefei Comprehensive National Science Center

To investigate the circuit-level neural mechanisms of behavior, simultaneous imaging of neuronal activity in multiple cortical and subcortical regions is highly desired. Miniature head-mounted microscopes offer the capability of calcium imaging in freely behaving animals. However, implanting multiple microscopes on a mouse brain remains challenging due to space constraints and the cumbersome weight of the ***, we present TINIscope, a Tightly Integrated Neuronal Imaging microscope optimized for electronic and opto-mechanical design. With its compact and lightweight design of 0.43 g, TINIscope enables unprecedented simultaneous imaging of behavior-relevant activity in up to four brain regions in ***-of-concept experiments with TINIscope recorded over 1000 neurons in four hippocampal subregions and revealed concurrent activity patterns spanning across these regions. Moreover, we explored potential multi-modal experimental designs by integrating additional modules for optogenetics, electrical stimulation or local field potential recordings. Overall, TINIscope represents a timely and indispensable tool for studying the brain-wide interregional coordination that underlies unrestrained behaviors.

关键词： miniature microscope multiple sites calcium imaging multimodal integration hippocampus