检索结果-内蒙古大学图书馆

Approaching the Fundamental Limit of Orbital-Angular-Momentum Multiplexing Through a Hologram Metasurface

Physical Review Applied 2021年第6期16卷 064042-064042页

作者： Shuai S.A. Yuan Jie Wu Menglin L.N. Chen Zhihao Lan Liang Zhang Sheng Sun Zhixiang Huang Xiaoming Chen Shilie Zheng Li Jun Jiang Xianmin Zhang Wei E.I. Sha College of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China Department of Education of Anhui Province Ministry of Education and the Key Laboratory of Electromagnetic Environmental Sensing Anhui University Hefei 230039 China Department of Electrical and Electronic Engineering The University of Hong Kong Hong Kong Department of Electronic and Electrical Engineering University College London Torrington Place London WC1E 7JE United Kingdom Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Hefei Normal University Hefei 230601 China School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu 611731 China School of Information and Communications Engineering Xi’an Jiaotong University Xi’an 710049 China

Establishing and approaching the fundamental limit of orbital-angular-momentum (OAM) multiplexing are necessary and increasingly urgent for current multiple-input multiple-output research. In this work, we elaborate the fundamental limit in terms of independent scattering channels (or the degrees of freedom of scattered fields) through angular-spectral analysis, in conjunction with a rigorous Green’s function method. The scattering-channel limit is universal for arbitrary spatial-mode multiplexing, which is launched by a planar electromagnetic device, such as antenna, metasurface, etc., with a predefined physical size. As a proof of concept, we demonstrate both theoretically and experimentally the limit by a phase-only metasurface hologram that transforms orthogonal OAM modes to plane-wave modes scattered at critically separated angular-spectral regions. Particularly, a minimax optimization algorithm is applied to suppress angular-spectrum aliasing, achieving good performances in both full-wave simulation and experimental measurement at microwave frequencies. This work offers a theoretical upper bound and corresponding approach route for engineering designs of OAM multiplexing.

关键词： Angular momentum of light Polarization of light Spatial profiles of optical beams Devices Metamaterials Surfaces Holography Light scattering

来源：评论

学校读者我要写书评

暂无评论

Curvature-property coupling governed heat transfer deterioration in supercritical helically coiled tubes: Mechanistic insights and mitigation strategies via structural parametrization

引用

International Journal of Thermal sciences 2025年 215卷

作者： Chang, Fucheng Xin, Jiaxing Wu, Xiaoyi Li, Liwei Li, Huixiong Zhu, Yanlin National Key Lab of Aerospace Power System and Plasma Technology School of Mechanical Engineering Xi'an Jiaotong University Xi'an710049 China China Special Equipment Testing and Research Institute Beijing100029 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China Shanghai Nuclear Engineering Research & Design Institute Co. Ltd Shanghai200233 China

The unique thermo-hydrodynamic coupling phenomena in the helically coiled tube (HCT) handling supercritical fluids present both opportunities and challenges for next-generation compact heat exchangers. While the pronounced thermophysical property variations near pseudo-critical temperatures (Tpc) and curvature-induced secondary flows synergistically enhance heat transfer coefficient (HTC), their nonlinear coupling mechanisms may unexpectedly provoke severe heat transfer deterioration (HTD). Through systematic numerical investigations, this study reveals that circumferential wall temperature inhomogeneity (CWTI) exhibits an inverted N-shaped evolution, providing valuable insights for thermal homogenization design near Tpc. The secondary flow Reynolds number (Se), quantifying secondary flow intensity, shows a monotonic increase with decreasing coil diameter (Dc) or inner diameter (Di), reaching saturation in high-enthalpy regions. Notably, CWTI demonstrates non-monotonic behavior, achieving minimum values near Tpc before manifesting distinct rebound characteristics near Tpc conditions. Parametric analysis establishes that: (1) Elevating heat flux (q) increases Se, reducing Dc boosts it by 50.3 %, and decreasing Di raises it by 60.0 %. (2) HTD predominantly initiates at the outer wall under high-q conditions, with Dc reduction achieving HTD suppression and 26.9 % enhancement in the local HTC;(3) Reducing the Di results in a reduction of maximum CWTI by 22.5 %–28.6 %, suggesting that structural parametrization effectively mitigates wall temperature non-uniformity, thus suppressing the HTD. While centered on supercritical water, the dimensionless scaling relationships demonstrate extendibility to other media, with the curvature-property coupling mechanism both elucidating fundamental interactions and guiding robust heat exchanger design. © 2025 Elsevier Masson SAS

关键词： Electric heating

来源：评论

学校读者我要写书评

暂无评论

Tool Path Generation Method for Three-dimensional Vibration-assisted Machining 16

Tool Path Generation Method for Three-dimensional Vibration-...

引用

16th IEEE International Conference on Mechatronics and Automation, ICMA 2019

作者： Wang, Guilian Lv, Bingrui Liu, Bin Mu, Haozhi Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China Tianjin Laboratory of Control Theory and Applications in Complicated System Tianjin300384 China School of Electrical and Electronic Engineering Tianjin University of Technology Tianjin300384 China

ISBN: (纸本)9781728116983

In this paper, a new tool path generation method is proposed for the 3D (three-dimensional) vibration-assisted 6-DOF (six degree of freedom) machine tool machining system. The tool feed path is generated by the tangent point method and the coordinate transformation theory. It is worth noting that this method needle is only used when the tool and workpiece surface topography can be mathematically described. Finally, a numeric simulation method is used to simulate the tool path which is required when machining workpiece surfaces with different topography tools. The results show that the tool path generation method is widely applicable to tools and workpieces of various shapes, and it is of great significance to reveal the influences of different tool shapes on the tool path. © 2019 IEEE.

关键词： Machine tools

来源：评论

学校读者我要写书评

暂无评论

Corrigendum to “Oscillation-free source term inversion of atmospheric radionuclide releases with joint model bias corrections and non-smooth competing priors” [J. Hazard. Mater. 440 (2022) 129806]

引用

Journal of Hazardous Materials 2023年 445卷

作者： Sheng Fang Xinwen Dong Shuhan Zhuang Zhijie Tian Tianfeng Chai Yuhan Xu Yungang Zhao Li Sheng Xuan Ye Wei Xiong Institute of Nuclear and New Energy Technology Collaborative Innovation Centre of Advanced Nuclear Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education Tsinghua University Beijing 100084 China China Institute for Radiation Protection Taiyuan 030006 China NOAA Air Resources Laboratory (ARL) NOAA Center for Weather and Climate Prediction 5830 University Research Court College Park MD 20740 USA Cooperative Institute for Climate and Satellites University of Maryland College Park MD 20740 USA Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and Technology Beijing Normal University Beijing 100875 China CTBT Beijing National Data Centre and Beijing Radionuclide Laboratory Beijing 100085 China CMA Earth System Modeling and Prediction Center (CEMC) Beijing 100081 China

来源：评论

学校读者我要写书评

暂无评论

Photocatalytic C-H Silylation of Heteroarenes by Using Trialkylhydrosilanes

Photocatalytic C-H Silylation of Heteroarenes by Using Trial...

引用

中国化学会第二届全国有机自由基化学会议

作者：刘石惠张永强 State Key Laboratory of Bioengineering Reactor Shanghai Key Laboratory of New Drug Design and School of Pharmacy East China University of Science and Technology

芳杂基三烷基硅烷,是一类重要药物骨架和有机合成中间体。三烷基氢硅烷参与的芳杂环碳氢键硅化反应是合成此类结构最有效的方式。本研究,聚焦该类结构的绿色高效合成,将交叉去氢偶联反应技术扩展至碳硅键构建之中,发展了一类可见光催化... 详细信息

芳杂基三烷基硅烷,是一类重要药物骨架和有机合成中间体。三烷基氢硅烷参与的芳杂环碳氢键硅化反应是合成此类结构最有效的方式。本研究,聚焦该类结构的绿色高效合成,将交叉去氢偶联反应技术扩展至碳硅键构建之中,发展了一类可见光催化的芳杂环碳氢键硅化反应。该方法可有效兼容大体积三烷基氢硅烷;缺电子芳杂环,富电子芳杂环,以及氰基取代芳环都可有效参与反应;尤其需要指出的是,以三异丙基硅硫醇替代过氧化物,反应同样可以有效进行,显示出更优的区域选择性。拓展研究表明,这些含大位阻三烷基硅基的芳杂环,对各种基于碳硅键断裂的偶联反应显示出较高反应活性,为复杂生物活性分子高效合成和快速修饰提供了简洁高效的反应工具。

关键词：碳氢键偶联反应 Photocatalytic C-H Silylation of Heteroarenes by Using Trialkylhydrosilanes

来源：评论

学校读者我要写书评

暂无评论

Synthesis of 2-Quinolinones via a Hypervalent Iodine(Ⅲ)-Mediated Intramolecular Decarboxylative Heck-Type Reaction at Room Temperature

Synthesis of 2-Quinolinones via a Hypervalent Iodine(Ⅲ)-Med...

引用

中国化学会第二届全国有机自由基化学会议

作者：樊化强张永强王卫 State Key Laboratory of Bioengineering Reactor Shanghai Key Laboratory of New Drug Design and School of Pharmacy East China University of Science and Technology

喹啉酮是一类重要的含氮杂环,表现出广泛的生物活性。邻烯基苯胺及其衍生物的内酰胺化是合成此类结构最为有效的方式之一。然而传统方法通常以剧毒的光气制品,一氧化碳或二氧化碳为羰基源,需要在高温条件下使用昂贵而具有毒性的过渡金... 详细信息

喹啉酮是一类重要的含氮杂环,表现出广泛的生物活性。邻烯基苯胺及其衍生物的内酰胺化是合成此类结构最为有效的方式之一。然而传统方法通常以剧毒的光气制品,一氧化碳或二氧化碳为羰基源,需要在高温条件下使用昂贵而具有毒性的过渡金属或强碱介导反应的进行,存在反应条件苛刻,官能团兼容性差的缺点,不利于进一步工业放大合成。鉴于此,以邻烯基苯草氨酸为原料,我们发展了一类三价碘介导的分子内脱羧Heck反应,通过内酰胺化的方式,在无金属条件下,实现了多样性喹啉-2(1H)-酮结构的高效构建。该反应体系绿色温和,以易于制备的草胺酸为羰基源,表现出优异的化学选择性和官能团兼容性。通过进一步研究,我们初步阐明了环张力诱导碘氧键断裂的自由基脱羧机制,为设计新的三价碘介导自由基脱羧偶联反应指明了方向。

关键词：官能团 Mediated Intramolecular Decarboxylative Heck-Type Reaction at Room Temperature Synthesis of 2-Quinolinones via a Hypervalent Iodine

来源：评论

学校读者我要写书评

暂无评论

Unified Rendering Array Driver Runtime Optimization for Graphic Application 6

Unified Rendering Array Driver Runtime Optimization for Grap...

引用

6th Annual 2018 International Conference on Geo-Spatial Knowledge and Intelligence, GSKI 2018

作者： Ma, Chengcheng Tian, Ze Liu, Honghong Nie, Zhao China Aeronautical Computing Research Institute China Aviation Key Laboratory of Science and Technology on Integrated Circuit and Micro-System Design P.O. Box 710068 China Xiangteng Microelectronics Technology Co. LTD P.O. Box 710068 China

As the core of GPU processing, the performance of Unified rendering array is directly affected by the shader driver. On the basis of research the structure of Unified rendering array processing, this paper proposes a runtime Unified rendering array driver optimization method for graphical application, can according to different graphics application scenario runtime to generate optimized Unified rendering array driver, testing on graphics processors FPGA verification environment, driven by the runtime optimization compared with the traditional full function driver, performance increased by 55% - 270%. © Published under licence by IOP Publishing Ltd.

关键词： Array processing

来源：评论

学校读者我要写书评

暂无评论

Research on Stress-Relaxation Property of Different Layers ment under Compression 16

Research on Stress-Relaxation Property of Different Layers m...

引用

16th IEEE International Conference on Mechatronics and Automation, ICMA 2019

作者： Zhou, Jinlai Song, Yang Shi, Xue Xu, Chenguang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control Tianjin University of Technology School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China Periodontitis Department Tianjin Stomatological Hospital Tianjin300041 China

ISBN: (纸本)9781728116983

As a connective tissue connecting teeth and alveolar bone, periodontal ligament (PDL) has the mechanical properties of nonlinearity, viscoelasticity, anisotropy. In this paper, the pig mandibular central incisors were taken as subjects, a loading machine(CARE-MI00) was used to perform compression tests and the PDL stress-relaxation characteristics under different strain conditions were obtained. The stress-time curves and the relaxation modulus curves were obtained. The three-parameters Zener model and five-parameter generalized Maxwell model proposed by the author were used to fit the data. The experimental results show that the elastic modulus of PDL decreases gradually in the apex(ranges from 2.64 to 3.06 MPa), cervical margin(ranges from 1.44 to 1.76 MPa) and midroot (ranges from 1.03 to 1. 06MPa). Zener model has a relatively high fitting degree, and the squared correction coefficient is about 0.98, however, the adjusted R square of the five-parameter model was above 0.99. Compared with the Zener model, the five-parameter model can better reflect the sudden drop of relaxation modulus at the initial stage, which is more suitable for describing stress-relaxation in viscoelastic behavior of PDL. The advantage of this paper is to compare the descriptive ability of three-parameter and five-parameter generalized Maxwell equation to the mechanical properties of PDL and to provide an effective procedure for the preparation of PDL specimens. © 2019 IEEE.

关键词： Elastic moduli

来源：评论

学校读者我要写书评

暂无评论

Prediction of monolayered ferromagnetic CrMnI6 as an intrinsic high-temperature quantum anomalous Hall system

引用

Physical Review B 2020年第11期102卷 115413-115413页

作者： Huisheng Zhang Wenjia Yang Ping Cui Xiaohong Xu Zhenyu Zhang Key Laboratory of Magnetic Molecules and Magnetic Information Materials of the Ministry of Education and Research Institute of Materials Science Shanxi Normal University Linfen 041004 China International Center for Quantum Design of Functional Materials (ICQD) Hefei National Laboratory for Physical Sciences at Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei Anhui 230026 China Key Laboratory of Strongly-Coupled Quantum Matter Physics Chinese Academy of Sciences School of Physical Sciences University of Science and Technology of China Hefei Anhui 230026 China

Quantized Hall conductance without an external magnetic field, known as the quantum anomalous Hall effect (QAHE), may have important applications in dissipationless spintronics, yet to date, it has only been realized in magnetically doped topological insulators and at very low temperatures. Here we design a physically realistic system for realizing QAHE by expanding the recently discovered two-dimensional ferromagnetic insulators as a new class of candidate materials. Based on first-principles calculations, we predict that a CrMnI6 monolayer is energetically stable and can be readily exfoliated. This system is further shown to be a ferromagnetic insulator, with a transition temperature of ∼87K, higher than that of CrI3. Most strikingly, such a monolayer is characterized as an intrinsic QAHE system with a high Chern number of C = 2, and the underlying mechanism for the nontrivial topology is attributed to the two inequivalent subset sites of the Cr and Mn atoms. The present study thus provides an ideal platform for realizing high-temperature QAHE beyond the prevailing materials class of magnetically doped topological insulators.

关键词： First-principles calculations Topological materials 2-dimensional systems Ferromagnets Density functional theory Wannier function methods k dot p method

来源：评论

学校读者我要写书评

暂无评论

Optimization of Manufacturing Process and Experimental Verification of Vulnerable Part in reactor

引用

IOP Conference Series: Earth and Environmental science 2020年第1期585卷

作者： Yang Bo Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institution of China Sichuan ChengDu 610041

The technical requirements of the control rod driving mechanism of the third generation PWR nuclear power plant are higher. The latch parts are designed with double tooth structure and welded on the wear-resistant surface by cobalt-based alloy surfacing. According to the structural characteristics and manufacturing process difficulties, a special welding device is developed. According to the test and finite element simulation, the related process parameters are optimized. The trial production of the parts was completed, and the parts were tested by metallography, liquid permeation test, hardness test and thermal life test. The results show that the latch parts have high hardness and wear resistance, and meet the requirements of the driving mechanism operation life of the third generation PWR nuclear power plant.

关键词：

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：