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Optoelectronics Letters 2021年第10期17卷 622-625页

作者： ZHU Zhiyan ZHUO Ming WANG Tianran hou zhanqiang National University of Defense Technology Changsha 410000China

2,4,6-trinitrotoluene(TNT)has a strong explosive force and environmental toxicity,with the increasing threat of terrorist attacks worldwide,the high sensitivity detection of nitroaromatic explosives has become an urgent problem to be solved,and now the commonly used detection method is to use the optical principle,combined with large and expensive equipment to detect *** order to detect the content of TNT in bad environment quickly and in real time,surface acoustic wave technology was proposed to detect different concentrations of *** this paper,an ultra-sensitive TNT sensor was fabricated based on the surface acoustic wave *** detection of TNT was achieved by recognizing the shift of resonance ***,the whole process for the detection was done in 30 min,dedicating the rapid/real-time application of the *** study focused on the transfer characteristics of resonance frequencies at different *** frequency of surface sound waves varies greatly at high concentration because the modified IDT(interdigital transducers)electrodes were utilized,which is easy to work under different concentrations of *** proposed sensor has the advantages of real-time,simple and convenient detection,which provides a valuable method for the real-time detection of TNT.

关键词： wave modified utilized

0.04 degree-per-hour MEMS disk resonator gyroscope with high-quality factor (510 k) and long decaying time constant(74.9 s)

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Microsystems & Nanoengineering 2018年第1期4卷 46-56页

作者： Qingsong Li Dingbang Xiao Xin Zhou Yi Xu Ming Zhuo zhanqiang hou Kaixuan He Yongmeng Zhang Xuezhong Wu College of Intelligence Science National University of Defense TechnologyChangsha 410073China Laboratory of Science and Technology on Integrated Logistics Support National University of Defense TechnologyChangsha 410073China State Key Laboratory of ASIC and System School of MicroelectronicsFudan UniversityShanghai 200433China East China Institute of Photo-Electron IC Bengbu 233042China

The disk resonator gyroscope is an attractive candidate for high-performance MEMS *** gyroscope consists of a sensor and readout electronics,and the characteristics of the sensor directly determine the *** the sensor,a high-quality factor and long decaying time constant are the most important characteristics required to achieve high *** report a disk resonator gyroscope with a measured quality factor of 510 k and decaying time constant of 74.9 s,which is a record for MEMS silicon disk resonator gyroscopes,to the best of our *** improve the quality factor of the DRG,the quality factor improvement mechanism is first analyzed,and based on this mechanism two stiffness-mass decoupled methods,i.e.,spoke length distribution optimization and lumped mass configuration design,are proposed and demonstrated.A disk resonator gyroscope prototype is fabricated based on these design strategies,and the sensor itself shows an angle random walk as low as 0.001°/√h,demonstrating true potential to achieve navigation-grade *** gyroscope with readout electronics shows an angle random walk of 0.01°/√h and a bias instability of 0.04°/h at room temperature without compensation,revealing that the performance of the gyroscope is severely limited by the readout electronics,which should be further *** expect that the quality factor improvement methods can be used in the design of other MEMS gyroscopes and that the newly designed DRG can be further improved to achieve navigation-grade performances for high-end industrial,transportation,aerospace,and automotive applications.

关键词： resonator constant attractive

Preparation of Laser Cladding Coating Undercooling Cu-based Alloy and Co on Non-equilibrium Solidification Structure

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 463-472页

作者：田徐铭 CAO Shichao hou Kai hou Xiaopeng WANG Hongfu 张煜 Department of Outpatient Xinzhou People’s HospitalXinzhou 034099China School of Mechanical Engineering North University of ChinaTaiyuan 030051China Department of Neurosurgery Xinzhou People’s HospitalXinzhou 034099China Department of Orthopedics Xinzhou People’s HospitalXinzhou 034099China

The effect of the gradient content of Co element on the solidification process of Cu-based alloy under deep under cooling conditions was *** non-equilibrium solidification structure of the under cooled alloy samples were *** is found that the rapidly solidified alloy has undergone twice grain refinement during the undercooling *** and significance of the maximum undercooling refinement structure of Cu60Ni35Co5 at T=253 K were ***-density defects were observed,such as dislocations,stacking faults networks,and twinning *** standard FCC diffraction pattern represents that it is still a single-phase *** on the metallographic diagram,EBSD and TEM data analysis,it is illustrated that the occurrence of grain refinement under high undercooling is due to stress induced *** addition,the laser cladding technology is used to coat Co-based alloy(Stellite12) coating on 304 stainless steel substrate;the microstructure of the coating cross-section was *** was found that the microstructure of the cross-section is presented as columnar crystals,planar crystals,and disordered growth direction,so that the coating has better hardness and wear *** electrochemical corrosion of the substrate and coating,it can be seen that the Co and Cr elements present in the coating are more likely to form a dense passivation film,which improved the corrosion resistance of the coating.

关键词： non-equilibrium solidification structure undercooling recrystallization laser cladding coating

Integral Operators Between Fock Spaces

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Chinese Annals of Mathematics,Series B 2024年第2期45卷 265-278页

作者： Yongqing LIU Shengzhao hou School of Mathematics and Statistics Changshu Institute of TechnologySuzhou 215006JiangsuChina School of Mathematical Sciences Soochow UniversitySuzhou 215006JiangsuChina

In this paper,the authors study the integral operator■induced by a kernel functionφ(z,·)∈F_α~∞between Fock *** 1≤p≤∞,they prove that S_φ:F_α^(1)→F_α^(p)is bounded if and only if■where k_(a)is the normali... 详细信息

关键词： Fock spaces Integral operators Normalized reproducing kernel

Herbivore and native plant diversity synergistically resist alien plant invasion regardless of nutrient conditions

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Plant Diversity 2024年第5期46卷 640-647页

作者： Liping Shan Meng hou Key Laboratory of Wetland Ecology and Environment State Key Laboratory of Black Soils Conservation and UtilizationNortheast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China

Alien plant invasion success can be inhibited by two key biotic factors:native herbivores and plant ***,few studies have experimentally tested whether these factors interact to synergistically resist invasion success,especially factoring in changing global environments(*** enrichment).Here we tested how the synergy between native herbivores and plant diversity affects alien plant invasion success in various nutrient *** this purpose,we exposed alien plant species in potmesocosms to different levels of native plant diversity(4 vs.8 species),native generalist herbivores,and high and low soil nutrient *** found that generalist herbivores preferred alien plants to native plants,inhibiting invasion success in a native *** inhibition was amplified by highly diverse native ***,the amplified effect between herbivory and native plant diversity was independent of nutrient *** results suggest that a higher diversity of native communities can strengthen the resistance of native generalist herbivores to alien plant invasions by enhancing herbivory *** synergistic effect remains in force in nutrient-enriched habitats that are always invaded by alien plant *** results shed light on the effective control of plant invasions using multi-trophic means,even in the face of future global changes.

关键词： Biological invasion Biotic resistance Diversity conservation Plant-herbivore interactions Resource availability Global change

单晶金刚石微杯形谐振子的激光刻蚀制造方法(英文)

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强激光与粒子束 2015年第2期27卷 14-18页

作者：何汉辉李微肖定邦侯占强吴学忠国防科学技术大学机电工程与自动化学院长沙410073

基于激光刻蚀技术,提出了一种新型单晶金刚石微杯形谐振子的三维制造方法。由于高弹性模量、低热弹性阻尼以及较大的声波传递速度等优异的性质,单晶金刚石是一种理想的谐振子加工材料,但是金刚石硬度大且化学性能稳定,难以采用传统的加... 详细信息

基于激光刻蚀技术,提出了一种新型单晶金刚石微杯形谐振子的三维制造方法。由于高弹性模量、低热弹性阻尼以及较大的声波传递速度等优异的性质,单晶金刚石是一种理想的谐振子加工材料,但是金刚石硬度大且化学性能稳定,难以采用传统的加工方法成形加工。激光刻蚀因精度高,加工结构对称性好以及破损率低等特点,是一种较好的单晶金刚石加工方法。采用紫外激光加工机,研究了不同激光参数对单晶金刚石刻蚀质量的影响,通过合理设计微杯形谐振结构,规划激光刻蚀加工的轨迹,采用优化后激光刻蚀参数,实现了结构对称性较好的微杯形谐振子的加工,有望应用于高性能微杯形谐振陀螺。

关键词：单晶金刚石微杯形谐振子激光刻蚀制造方法

Fractures interaction and propagation mechanism of multi-cluster fracturing on laminated shale oil reservoir

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Petroleum Science 2024年第4期21卷 2600-2613页

作者： Jia-Xin Lv Bing hou Key Laboratory of Petroleum Engineering Ministry of Education China University of Petroleum (Beijing) State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum (Beijing) Department of Petroleum Engineering China University of Petroleum (Beijing) at Karamay

The continental shale reservoirs of Jurassic Lianggaoshan Formation in Sichuan Basin contain thin lamina, which is characterized by strong plasticity and developed longitudinal shell limestone *** improve the production efficiency of reservoirs by multi-cluster fracturing, it is necessary to consider the unbalanced propagation of hydraulic fractures and the penetration effect of fractures. This paper constructed a numerical model of multi-fracture propagation and penetration based on the finite element coupling cohesive zone method; considering the construction cluster spacing, pump rate,lamina strength and other parameters studied the influencing factors of multi-cluster fracture interaction propagation; combined with AE energy data and fracture mode reconstruction method, quantitatively characterized the comprehensive impact of the strength of thin interlayer rock interfaces on the initiation and propagation of fractures that penetrate layers, and accurately predicted the propagation pattern of hydraulic fractures through laminated shale oil reservoirs. Simulation results revealed that in the process of multi-cluster fracturing, the proportion of shear damage is low, and mainly occurs in bedding fractures activated by outer fractures. Reducing the cluster spacing enhances the fracture system's penetration ability, though it lowers the activation efficiency of lamina. The high plasticity of the limestone interlayer may impact the vertical propagation distance of the main fracture. Improving the interface strength is beneficial to the reconstruction of the fracture height, but the interface communication effect is limited. Reasonable selection of layers with moderate lamina strength for fracturing stimulation, increasing the pump rate during fracturing and setting the cluster spacing reasonably are beneficial to improve the effect of reservoir stimulation.

关键词： Laminated shale Multi-cluster fracturing Cross-layer Cohesive zone model Acoustic emission technique

In-Plane Dynamic Crushing Behaviors of a Vertex-Based Hierarchical Auxetic Honeycomb

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Acta Mechanica Solida Sinica 2024年第1期37卷 53-62页

作者： Yichen Zan Xiuhui hou Zichen Deng School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi'an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

Auxetic metamaterials,which exhibit the negative Poisson’s ratio(NPR)effect,have found wide applications in many engineering ***,their high porosity inevitably weakens their bearing capacity and impact *** improve the energy absorption efficiency of auxetic honeycombs,a novel vertex-based hierarchical star-shaped honeycomb(VSH)is designed by replacing each vertex in the classical star-shaped honeycomb(SSH)with a newly added self-similar *** analytical model is built to investigate the Young’s modulus of VSH,which shows good agreement with experimental results and numerical *** in-plane dynamic crushing behaviors of VSH at three different crushing velocities are investigated,and empirical formulas for the densification strain and plateau stress are *** results reveal more stable deformation modes for VSH,attributed to the addition of self-similar star-shaped ***,compared with SSH under the same relative densities,VSH exhibits better specific energy absorption and higher plateau ***,VSH is verified to be a better candidate for energy absorption while maintaining the auxetic *** study is expected to provide a new design strategy for auxetic honeycombs.

关键词： Vertex-based hierarchical star-shaped honeycomb Auxetic honeycomb Energy absorption Plateau stress Negative Poisson's ratio

An Improved Method for Approximating the Infinite-Horizon Value Function of the Discrete-Time Switched LQR Problem

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Journal of Systems Science & Complexity 2024年第1期37卷 22-39页

作者： hou Tan LI Yuanlong LIN Zongli Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai 200240China Charles L.Brown Department of Electrical and Computer Engineering University of VirginiaCharlottesvilleVA 22904-4743USA

This paper considers the problem of approximating the infinite-horizon value function of the discrete-time switched LQR *** particular,the authors propose a new value iteration method to generate a sequence of monotonically decreasing functions that converges exponentially to the value *** method facilitates us to use coarse approximations resulting from faster but less accurate algorithms for further value iteration,and thus,the proposed approach is capable of achieving a better approximation for a given computation time compared with the existing *** numerical examples are presented in this paper to illustrate the effectiveness of the proposed method.

关键词： Optimal control switched linear systems switched LQR problem.

Theoretical study on the stability of nanobubbles and its verification in molecular dynamics simulation

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Particuology 2024年第4期87卷 99-105页

作者： Sheng Mi Chaofeng hou Wei Ge School of Chemical Engineering and Technology Tianjin UniversityTianjin300072China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing.100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China

The stability of vapor nanobubbles in bulk liquid was investigated theoretically and the critical bubble size was derived from macroscale thermodynamic equations,below which the system destabilizes with sharp drop in *** critical size was quantitatively verified in molecular dynamic simulation using the Lennard-Jones model of argon,where stronger attraction between the molecules at lower density is found to contribute most to the drop of system pressure and,as the Laplace pressure on the curved bubble interface fails to balance the pressure difference across the interface,the bubbles become *** theoretical model could be extended to other systems where reliable equations of state and interfacial tension are available.

关键词： Nanobubble Stability Phase diagram Critical size