检索结果-内蒙古大学图书馆

Indentation behavior of a semi-infinite piezoelectric semiconductor under a rigid flat-ended cylindrical indenter

Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 649-662页

作者： Shijing GAO Lele ZHANG Jinxi LIU Guoquan NIE Weiqiu CHEN State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China Hebei Key Laboratory for Mechanics of Intelligent Materials and Structures Department of Engineering MechanicsShijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Computer Aided Design and Computer Graphics Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou 310027China

This paper theoretically studies the axisymmetric frictionless indentation of a transversely isotropic piezoelectric semiconductor(PSC)half-space subject to a rigid flatended cylindrical *** contact area and other surface of the PSC half-space are assumed to be electrically *** the Hankel integral transformation,the problem is reduced to the Fredholm integral equation of the second *** equation is solved numerically to obtain the indentation behaviors of the PSC half-space,mainly including the indentation force-depth relation and the electric potential-depth *** results show that the effect of the semiconductor property on the indentation responses is limited within a certain range of variation of the steady carrier *** dependence of indentation behavior on material properties is also analyzed by two different kinds of *** element simulations are conducted to verify the results calculated by the integral equation technique,and good agreement is demonstrated.

关键词： piezoelectric semiconductor(PSC) insulating indenter electromechanical response singular integral equation finite element simulation

来源：评论

学校读者我要写书评

暂无评论

Linear Modulation of the Resonant Frequency of a Double-bubble Model Below an Air-Water Interface

Linear Modulation of the Resonant Frequency of a Double-bubb...

引用

2024 OES China Ocean Acoustics, COA 2024

作者： Cheng, Xuan Li, Shiyu Gong, Zhixiong Fan, Jun School of Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai China School of Ocean and Civil Engineering Shanghai Jiao Tong University State Key Laboratory of Ocean Engineering Key Laboratory of Marine Intelligent Equipment and System Shanghai China School of Ocean and Civil Engineering Key Laboratory of Marine Intelligent Equipment and System State Key Laboratory of Ocean Engineering Shanghai China

ISBN: (纸本)9798350340297

The study of sound wave propagation across the air-water interface is important for several potential applications, e.g., acoustic communication between underwater environments and air. However, only 0.1% of the power of the incident wave perpendicular to the interface can cross the interface owing to the large acoustic-impedance mismatch between air and water. This renders the propagation of acoustic energy between the media inefficient, leading to the failure of effective acoustic communication between these media. This situation could be solved using designed bubble systems because bubbles are good acoustic impedance matchers. The existing research is mainly limited periodic single-bubble systems, which are not suitable for acoustic propagation in the broadband frequency range. This is because the large sound transmission coefficient between the air-water interface occurs only near a sharp resonant frequency and decreases rapidly away from the resonance. In this work, we propose a periodic double-bubble model below the air-water interface for efficient propagation over a wide frequency range. A numerical simulation model based on COMSOL was developed and validated through comparison with a theoretically analyzed periodic single-bubble system. Then, a periodic double- bubble model was built to study the modulation effect of the resonance frequency versus the vertical interval between the two bubbles. Numerical simulations show that the resonant frequency of the periodic double-bubble system varies linearly with the vertical interval. Therefore this study offers a potential method for designing broadband acoustic communication techniques across the sea-air interface. © 2024 IEEE.

关键词： Acoustic impedance

来源：评论

学校读者我要写书评

暂无评论

Nonlinear Disturbance Observer of Clutch Slipping Torque for Multi-Mode Hybrid Electric Vehicles

引用

Journal of Shanghai Jiaotong University (Science) 2024年 1-8页

作者： Peng, Cheng Chen, Li Fu, Shenglai Key Laboratory of Marine Intelligent Equipment and System of Ministry of Education School of Naval Architecture Ocean & ampCivil Engineering Shanghai Jiao Tong University Shanghai200240 China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai200240 China

Clutch slipping torque varies complicatedly and has a strong nonlinearity during the mode transition of hybrid electric vehicles. In order to estimate the clutch slipping torque, an online estimator based on the nonlinear disturbance observer (NDO) is proposed. First, an estimation-oriented model of the clutch slipping torque is established based on the LuGre friction model. Next, the NDO is designed to estimate the unknown part of clutch slipping torque based on the dynamics of the output shaft, while the output shaft torque required by NDO is estimated by a Luenberger state observer. To verify the effectiveness of the proposed estimator, experiments are conducted under different initial slipping speeds and inlet oil temperatures. The results show that the proposed estimator gains high accuracy. © Shanghai Jiao Tong University 2024.

关键词： Clutches

来源：评论

学校读者我要写书评

暂无评论

A comparative study on mechanical and vibroacoustic performance of sandwich cylindrical shells with positive,negative,and zero Poisson’s ratio cellular cores

引用

Journal of Ocean Engineering and Science 2024年第4期9卷 379-390页

作者： Qing Li Peichang Li Yongjin Guo Xi’an Liu State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China China Ship Development and Design Center Wuhan430064China MOE Key Laboratory of Marine Intelligent Equipment and System Shanghai Jiao Tong UniversityShanghai200240China

Deep-sea submersibles are significant mobile platforms requiring multi-functional capabilities that are strongly determined by the constituent *** cylindrical protective cover can be advanced by designing their sandwiched cellular materials whose physical properties can be readily parameterized and flexibly *** honeycomb materials are capable of possessing tuned positive,negative,or zero Poisson’s ratios(PPR,NPR,and ZPR),which is expected to produce distinct physical performance when utilized as a cellular core of cylindrical shells for the deep-sea submersibles.A novel cylindrical meta-structure sandwiched with the semi-re-entrant ZPR metamaterial has been designed as well as its similarly-shaped sandwich cylindrical shell structures with PPR and NPR *** mechanical and vibroacoustic performance of sandwich cylindrical shells with cellular materials featuring a full characteristic range of Poisson’s ratios are then compared systematically to explore their potential for engineering applications on submerged pressure-resistant *** respective unit cells are designed to feature an equivalent load-bearing *** properties of pressure resistance,buckling,and sound insulation are simulated,respectively,and the orders of each property are then generalized by systematic *** results indicate that the PPR honeycomb core takes advantage of higher structural strength and stability while the ZPR one yields better energy absorption and sound insulation *** NPR one yields moderate properties and has the potential for lower circumferential *** work explores the application of cellular materials with varied Poisson’s ratios and provides guidance for the multi-functional design of sandwich cylindrical meta-structures.

关键词： Sandwich cylindrical shells Poisson’s ratio Pressure-resistant Buckling Vibroacoustic

来源：评论

学校读者我要写书评

暂无评论

High-performance self-powered ultraviolet to near-infrared photodetector based on WS_(2)/InSe van der Waals heterostructure

引用

Nano Research 2023年第5期16卷 7851-7857页

作者： Jinping Chen Zhen Zhang Yi Ma Jiying Feng Xiaoyu Xie Xiaoxuan Wang Aoqun Jian Yuanzheng Li Zhuxin Li Heng Guo Yizhi Zhu Qiannan Cui Zengliang Shi Chunxiang Xu State Key Laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast UniversityNanjing 210096China Micro Nano System Research Center Key Laboratory of Advanced Transducers and Intelligent Control System of the Ministry of Education&College of Information Engineering and ComputerTaiyuan University of TechnologyTaiyuan 030024China Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education Northeast Normal UniversityChangchun 130024China

van der Waals heterostructures(vdWHs)based on two-dimensional(2D)materials without the crystal lattice matching constraint have great potential for high-performance optoelectronic ***,a WS_(2)/InSe vdWH photodiode is proposed and fabricated by precisely stacking InSe and WS_(2)flakes through an all-dry transfer *** WS_(2)/InSe vdWH forms an n–n heterojunction with strong built-in electric field due to their intrinsic n-type semiconductor characteristics and energy-band alignments with a large Fermi level offset between WS_(2)and *** a result,the device displays excellent photovoltaic behavior with a large open voltage of 0.47 V and a short-circuit current of 11.7 nA under 520 nm light ***,a fast rising/decay time of 63/76μs,a large light on/off ratio of 105,a responsivity of 61 mA/W,a high detectivity of 2.5×10^(11) Jones,and a broadband photoresponse ranging from ultraviolet to near-infrared(325–980 nm)are achieved at zero *** study provides a strategy for developing high-performance self-powered broadband photodetectors based on 2D materials.

关键词： two-dimensional materials van der Waals heterostructure self-powered photodetector photocurrent

来源：评论

学校读者我要写书评

暂无评论

Extended DMPs Framework for Position and Decoupled Quaternion Learning and Generalization

引用

Chinese Journal of Mechanical Engineering 2022年第4期35卷 227-239页

作者： Zhiwei Liao Fei Zhao Gedong Jiang Xuesong Mei State Key Laboratory for Manufacturing System Engineering Xi’an Jiaotong UniversityXi’an 710049China Shaanxi Key Laboratory of Intelligent Robots and School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China

Dynamic movement primitives(DMPs)as a robust and efcient framework has been studied widely for robot learning from *** DMPs framework mainly focuses on the movement learning in Cartesian or joint space,and can’t properly represent end-efector *** this paper,we present an extended DMPs framework(EDMPs)both in Cartesian space and 2-Dimensional(2D)sphere manifold for Quaternion-based orientation learning and *** mixture model and Gaussian mixture regression(GMM-GMR)are adopted as the initialization phase of EDMPs to handle multi-demonstrations and obtain their mean and ***,some evaluation indicators including reachability and similarity are defned to characterize the learning and generalization abilities of ***,a real-world experiment was conducted with human demonstrations,the endpoint poses of human arm were recorded and successfully transferred from human to the *** experimental results show that the absolute errors of the Cartesian and Riemannian space skills are less than 3.5 mm and 1.0°,*** Pearson’s correlation coefcients of the Cartesian and Riemannian space skills are mostly greater than *** developed EDMPs exhibits superior reachability and similarity for the multi-space skills’learning and *** research proposes a fused framework with EDMPs and GMM-GMR which has sufcient capability to handle the multi-space skills in multi-demonstrations.

关键词： Learning from demonstration Dynamic movement primitives 2D sphere manifold Gaussian mixture model Gaussian mixture regression Quaternion-based orientation

来源：评论

学校读者我要写书评

暂无评论

3D reconstruction and defect pattern recognition of bonding wire based on stereo vision

引用

CAAI Transactions on Intelligence Technology 2024年第2期9卷 348-364页

作者： Naigong Yu Hongzheng Li Qiao Xu Ouattara Sie Essaf Firdaous Faculty of Information Technology Beijing University of TechnologyBeijingChina Beijing Key Laboratory of Computing Intelligence and Intelligent System Beijing University of TechnologyBeijingChina Engineering Research Center of Digital Community Ministry of EducationBeijingChina College of Robotic UniversitéFélix Houphouët‐BoignyAbidjanCôte d’Ivoire

Non-destructive detection of wire bonding defects in integrated circuits(IC)is critical for ensuring product quality after ***-processing-based methods do not provide a detailed evaluation of the three-dimensional defects of the bonding ***,a method of 3D reconstruction and pattern recognition of wire defects based on stereo vision,which can achieve non-destructive detection of bonding wire defects is *** contour features of bonding wires and other electronic components in the depth image is analysed to complete the 3D reconstruction of the bonding *** to filter the noisy point cloud and obtain an accurate point cloud of the bonding wire surface,a point cloud segmentation method based on spatial surface feature detection(SFD)was *** can extract more distinct features from the bonding wire surface during the point cloud segmentation ***,in the defect detection process,a directional discretisation descriptor with multiple local normal vectors is designed for defect pattern recognition of bonding *** descriptor combines local and global features of wire and can describe the spatial variation trends and structural features of *** experimental results show that the method can complete the 3D reconstruction and defect pattern recognition of bonding wires,and the average accuracy of defect recognition is 96.47%,which meets the production requirements of bonding wire defect detection.

关键词： bonding wire defect detection point cloud point cloud segmentation

来源：评论

学校读者我要写书评

暂无评论

A Visual-based Servo Control Method for Space Manipulator Assisted Docking 6

A Visual-based Servo Control Method for Space Manipulator As...

引用

6th IEEE Information Technology and Mechatronics Engineering Conference, ITOEC 2022

作者： Liang, Changchun Wang, Rui Liu, Xin Beijing Institute of Spacecraft System Engineering Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing100094 China

ISBN: (纸本)9781665431859

Focusing on task of space manipulator assisting docking, a visual-servo close loop control method is proposed, the full system simulation model established, and simulated in control-dynamics closed loop for verification, simulations results indicates that the relative position (orientation) can be adjusted under the proposed method in a smooth way, the method can be referenced by future manipulators tasks like OOS. © 2022 IEEE.

关键词： Manipulators

来源：评论

学校读者我要写书评

暂无评论

Thermal engineering in ALD-grown ZGO thin films for high-performance photodetectors

引用

材料科学技术（英文版） 2025年第6期209卷 19-26页

作者： Si-Tong Ding Yu-Chang Chen Cai-Yu Shi Lei Shen Qiu-Jun Yu Lang-Xi Ou Ze-Yu Gu Na Chen Ting-Yun Wang David Wei Zhang Hong-Liang Lu State Key Laboratory of ASIC and System Shanghai Institute of Intelligent Electronics & SystemsSchool of MicroelectronicsFudan UniversityShanghai 200433China Zhangjiang Fudan International Innovation Center Shanghai 201203China National Integrated Circuit Innovation Center Shanghai 201203China Key Laboratory of Specialty Fiber Optics and Optical Access Networks Shanghai Institute Communication and Data ScienceShanghai UniversityShanghai 200444China State Key Laboratory of ASIC and System Shanghai Institute of Intelligent Electronics & SystemsSchool of MicroelectronicsFudan UniversityShanghai 200433China Zhangjiang Fudan International Innovation Center Shanghai 201203China National Integrated Circuit Innovation Center Shanghai 201203China Jiashan Fudan Institute Jiaxing 314100China

Doped gallium oxide-based thin films are a class of wide-band semiconductor materials with the ad-vantages of chemically stable,tunable bandgap,and offer the benefit of ultraviolet *** order to obtain photodetectors(PDs)with superior response,higher demands are placed on the quality of growth and processing of doped *** this work,Zn-doped ternary metal oxide ZnGaO(ZGO)thin films were grown using the atomic layer deposition technique and annealed at different temperatures under an oxy-gen *** results showed that the high-quality ZGO films with good uniformity,high visible light transmittance,low roughness,and significant reduction of oxygen vacancies were obtained after ***,metal-semiconductor-metal PDs were prepared based on the studied ZGO *** responsivity(R),detectivity(D*),and external quantum efficiency(EQE)of the optimized device are 61.8 A W-1,1.2 x 1012 Jones,and 255.9％,*** to the unannealed device,the an-nealed ZGO PD achieves a maximum 309-fold increase in *** thermal engineering work may provide a strong reference for the development of low-cost,large-area,high-performance ultraviolet *** it also broadens the application of ternary metal oxides in optoelectronics.

关键词： Atomic layer deposition Oxygen annealing ZGO thin films Photodetector Ultraviolet detection

来源：评论

学校读者我要写书评

暂无评论

Rethinking Mutual Information for Language Conditioned Skill Discovery on Imitation Learning 34

Rethinking Mutual Information for Language Conditioned Skill...

引用

34th International Conference on Automated Planning and Scheduling, ICAPS 2024

作者： Ju, Zhaoxun Yang, Chao Sun, Fuchun Wang, Hongbo Qiao, Yu Academy for Engineering and Technology Fudan University China Shanghai Artificial Intelligence Laboratory China State Key Laboratory of Intelligent Technology and System Tsinghua University China

ISBN: (纸本)9781577358893

Language-conditioned robot behavior plays a vital role in executing complex tasks by associating human commands or instructions with perception and actions. The ability to compose long-horizon tasks based on unconstrained language instructions necessitates the acquisition of a diverse set of general-purpose skills. However, acquiring inherent primitive skills in a coupled and long-horizon environment without external rewards or human supervision presents significant challenges. In this paper, we evaluate the relationship between skills and language instructions from a mathematical perspective, employing two forms of mutual information within the framework of language-conditioned policy learning. To maximize the mutual information between language and skills in an unsupervised manner, we propose an end-to-end imitation learning approach known as Language Conditioned Skill Discovery (LCSD). Specifically, we utilize vector quantization to learn discrete latent skills and leverage skill sequences of trajectories to reconstruct high-level semantic instructions. Through extensive experiments on language-conditioned robotic navigation and manipulation tasks, encompassing BabyAI, LORel, and CALVIN, we demonstrate the superiority of our method over prior works. Our approach exhibits enhanced generalization capabilities towards unseen tasks, improved skill interpretability, and notably higher rates of task completion success. Copyright © 2024, Association for the Advancement of Artificial Intelligence (***). All rights reserved.

关键词： Semantics

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：