检索结果-南通市图书馆

Compact electro-optic modulator on lithium niobate

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2022年第3期10卷 697-702页

作者： Bingcheng Pan Hongyuan Cao Yishu Huang Zong Wang kaixuan chen Huan Li Zejie Yu Daoxin Dai State Key Laboratory for Modern Optical Instrumentation Center for Optical&Electromagnetic ResearchCollege of Optical Science and EngineeringInternational Research Center for Advanced PhotonicsZhejiang UniversityZijingang CampusHangzhou 310058China Guangdong Provincial Key Laboratory of Optical Information Materials and Technology South China Academy of Advanced OptoelectronicsSouth China Normal UniversityHigher-Education Mega-CenterGuangzhou 510006China Jiaxing Key Laboratory of Photonic Sensing&Intelligent Imaging Jiaxing 314000China Intelligent Optics&Photonics Research Center Jiaxing Research Institute Zhejiang UniversityJiaxing 314000China Ningbo Research Institute Zhejiang UniversityNingbo 315100China

Fast electro-optic modulators with an ultracompact footprint and low power consumption are always highly desired for optical *** we propose and demonstrate a high-performance lithium niobate electro-optic modulator based on a new 2×2 Fabry–Perot *** this structure,the input and reflected beams are separated by introducing asymmetric multimode-waveguide gratings,enabling TE_(0)−TE_(1)mode *** measured results indicate that the fabricated modulator features a low excess loss of∼0.9dB,a high extinction ratio of∼21dB,a compact footprint of∼2120μm^(2),and high modulation speeds of 40 Gbps OOK and 80 Gbps PAM4 *** demonstrated modulator is promising for high-speed data transmission and signal processing.

关键词： modulator waveguide lithium

Band-like transport in non-fullerene acceptor semiconductor Y6

在线全文

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2022年第2期15卷 169-178页

作者： kaixuan chen Huan Wei Ping-An chen Yu Liu Jing Guo Jiangnan Xia Haihong Xie Xincan Qiu Yuanyuan Hu Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&International Science and Technology Innovation Cooperation Base for Advanced Display Technologies of Hunan Province School of Physics and ElectronicsHunan UniversityChangsha 410082China Shenzhen Research Institute of Hunan University Shenzhen 518063China

The recently reported non-fullerene acceptor(NFA)Y6 has been extensively investigated for high-performance organic solar ***,its charge transport property and physics have not been fully *** this work,we acquired a deeper understanding of the charge transport in Y6 by fabricating and characterizing thin-film transistors(TFTs),and found that the electron mobility of Y6 is over 0.3-0.4 cm^(2)/(V⋅s)in top-gate bottom-contact devices,which is at least one order of magnitude higher than that of another well-known NFA *** importantly,we observed band-like transport in Y6 spin-coated films through temperature-dependent measurements on *** is particularly amazing since such transport behavior is rarely seen in polycrystalline organic semiconductor *** morphology characterization and discussions indicate that the band-like transport originates from the unique molecule packing motif of Y6 and the special phase of the *** such,this work not only demonstrates the superior charge transport property of Y6,but also suggests the great potential of developing high-mobility n-type organic semiconductors,on the basis of Y6.

关键词： Y6 Thin-film transistors(TFTs) Mobility Band-like transport Film morphology

在线全文

学校读者我要写书评

暂无评论

共晶高熵合金成分设计的研究进展

稀有金属材料与工程 2024年第7期53卷 2083-2093页

作者：陈凯旋熊志平中国航空工业集团中国航空综合技术研究所北京100028 北京理工大学材料学院北京100081

近年来,共晶高熵合金由于优异的铸造性能以及优良的强塑性匹配受到了广泛关注,然而,目前存在着开发共晶高熵合金效率过低的问题,共晶高熵合金的成分设计始终是一项挑战。针对这一项挑战,国内外学者开发了多种共晶高熵合金的成分设计方... 详细信息

近年来,共晶高熵合金由于优异的铸造性能以及优良的强塑性匹配受到了广泛关注,然而,目前存在着开发共晶高熵合金效率过低的问题,共晶高熵合金的成分设计始终是一项挑战。针对这一项挑战,国内外学者开发了多种共晶高熵合金的成分设计方法来加快共晶高熵合金的开发速度,由最初的试错法,发展到后来的d轨道能级法、简单混合法、混合焓法、相图计算法以及机器学习辅助的方法等等。每种方法各有特点和局限性,本文对共晶高熵合金的成分设计方法进行了全面评述。

关键词：共晶合金高熵合金成分设计机器学习

Effect of Carbides and γ/γ' Eutectic on Crack Initiation and Propagation in Ni-based Superalloy

在线全文

学校读者我要写书评

暂无评论

Research and Application of Materials Science 2020年第2期2卷 33-42页

作者： Junwei QIN Xiaohua chen kaixuan chen Xinghai YANG Weiyang XIE Yanlin WANG Zidong WANG School of Science and Engineering University of Science and Technology BeijingBeijingChina State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijingChina

The Ni-based Udemit720Li superalloy tends to form largeγ/γ'eutectic on grain boundaries(GBs)during solidification due to the addition of excessive Al and Ti elements,which provides convenience to study the effect of carbide andγ/γ'eutectic on crack initiation and propagation during tensile *** this paper,Udemit720Li superalloy samples were prepared by induction melting casting method,arc melting and suction casting *** microstructure,tensile properties and mechanism of crack initiation and propagation in Ni-based superalloy fabricated by two methods are *** results exhibitγ/γ'eutectic accelerates the stress concentration at GB and thus leads to premature fracture *** samples with grain-boundary eutectic have higher strain hardening rate,but their cumulative and local misorientations are *** samples without eutectic at GB,the primary crack initiates at grain-boundary carbide along GB and extends along GB or into grain matrix,and exhibits better deformation performance and dislocation storage capacity within grains.

关键词： Superalloy Carbides Eutectic Crack

反思与展望:对新时代研究生社会实践的再认识

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

学位与研究生教育 2021年第8期 73-77页

作者：陈凯旋浙江大学党委研究生工作部杭州310058 西藏农牧学院学生工作处林芝860000

在简要回顾和梳理研究生社会实践的发展历程、分析当前研究生社会实践的现实困境和认识误区的基础上,从思政教育、知识生产和职业发展三重视角以及空间、功能和价值三个维度分析了社会实践的功能和特征,进而展望了新时代研究生社会实践... 详细信息

在简要回顾和梳理研究生社会实践的发展历程、分析当前研究生社会实践的现实困境和认识误区的基础上,从思政教育、知识生产和职业发展三重视角以及空间、功能和价值三个维度分析了社会实践的功能和特征,进而展望了新时代研究生社会实践的发展趋势。

关键词：社会实践研究生教育思政教育培养质量

Synthetic control of chiral pore surfaces in covalent organic frameworks for enantioselective separation of chiral drugs

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Shiguo Fu Xiaofeng Zhang kaixuan Wang Linfeng chen Fan Xia Yong Cui Yan Liu School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules and State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Faculty of Materials Science and Chemistry China University of Geosciences

Enantioselective separations of racemates using porous materials are highly attractive and significant in both fundamental research and technological applications. However, achieving controlled chiral pore surfaces to create the necessary driving force for enantiomer discrimination poses a fundamental challenge. Herein, we demonstrate that chiral covalent organic frameworks(COFs) possess the essential characteristics for effective enantioseparations through synthetic control over pore surfaces. We synthesized three 3D chiral COFs (CCOFs) featuring abundant chiral recognition sites on the pore walls via the condensation of enantiopure dialdehyde of 2,2′-dihydroxy-1,1′-binaphthyl and tetraamine. All CCOFs with high stability exhibit an 11-fold interpenetrated framework with tubular open channels, decorated with dihydroxyl or diethoxyl groups. The CCOFs with dihydroxyl groups serve as solid adsorbents for the adsorptive separation and solid-phase extraction of various chiral 1-phenylethanol-derived enantiomers, particularly racemic drugs, achieving up to 98%enantiomeric excess. In contrast, the CCOF with diethoxy groups is unable to resolve the racemates. These CCOF materials can be recycled and reused without any apparent loss of performance. Density functional theory (DFT) calculations reveal that the enantiospecific recognition arises from the well-organized chiral inner sphere and multiple chiral host-guest interactions.

关键词：

STUDY OF SUPERCONDUCTING MATERIAL YBa_(2)Cu_(3)O9-δ BY POSITRON ANNIHILATION TECHNIQUE

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 1988年第2期5卷 53-56页

作者： ZHU Shengyun LI Anli BAI Xixiang DU Hongshan LI Donghong ZHENG Xianmiao ZHANG Warding chen kaixuan Institute of Atomic Energy Beijing Department of Chemistry Beijiing UniversityBeijing Department of Physics Beij ing UniversityBeijing

Characteristics of superconducting and semiconductor materials with the same composition have been studied at room temperature,94K,and 77K by the positron annihilation *** results indicate that the phase transition of... 详细信息

关键词： technique state annihilation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

面向图像集分类的切空间稀疏表示算法

中国图象图形学报 2018年第7期23卷 961-972页

作者：陈凯旋吴小俊江南大学物联网工程学院无锡214122

目的在基于图像集的分类任务中,用SPD(symmetric positive definite)矩阵描述图像集,并考虑所得到的黎曼流形,已被证明对许多分类任务有较好的效果。但是,已有的经典分类算法大多应用于欧氏空间,无法直接应用于黎曼空间。为了将欧氏空... 详细信息

目的在基于图像集的分类任务中,用SPD(symmetric positive definite)矩阵描述图像集,并考虑所得到的黎曼流形,已被证明对许多分类任务有较好的效果。但是,已有的经典分类算法大多应用于欧氏空间,无法直接应用于黎曼空间。为了将欧氏空间的分类方法应用于解决图像集的分类,综合考虑SPD流形的LEM(Log-Euclidean metric)度量和欧氏空间分类算法的特性,实现基于图像集的分类任务。方法通过矩阵的对数映射将SPD流形上的样本点映射到切空间中,切空间中的样本点与图像集是一一对应的关系,此时,再将切空间中的样本点作为欧氏空间中稀疏表示分类算法的输入以实现图像集的分类任务。但是切空间样本的形式为对称矩阵,且维度较大,包含一定冗余信息,为了提高算法的性能和运行效率,使用NYSTR?M METHOD和(2D) ~2PCA(two-directional twodimensional PCA)两种方法来获得包含图像集的主要信息且维度更低的数据表示形式。结果在实验中,对人脸、物体和病毒细胞3种不同的对象进行分类,并且与一些用于图像集分类的经典算法进行对比。实现结果表明,本文算法不仅具有较高的识别率,而且标准差也相对较小。在人脸数据集上,本文算法的识别率可以达到78.26%,比其他算法高出10%左右,同时,具有最小的标准差2.71。在病毒数细胞据集上,本文算法的识别率可以达到58.67%,在所有的方法中识别率最高。在物体识别的任务中,本文算法的识别率可以达到96.25%,标准差为2.12。结论实验结果表明,与一些经典的基于图像集的分类算法对比,本文算法的识别率有较大的提高且具有较小的标准差,对多种数据集有较强的泛化能力,这充分说明了本文算法可以广泛应用于解决基于图像集的分类任务。但是,本文是通过(2D) ~2PCA和NYSTR?M METHOD对切空间中样本进行降维来获得更低维度的样本,以提高算法的运行速度和性能。如何直接构建维度更低,且具有判别性的SPD流形将是下一步的研究重点。

关键词： SPD流形图像集分类 NYSTROM METHOD 双相2维主成分分析((2D)^(2)PCA) 稀疏表示

在线全文

学校读者我要写书评

暂无评论

硅基片上模式复用技术进展

华南师范大学学报(自然科学版) 2016年第1期48卷 28-34+2页

作者：刘柳陈楷旋华南师范大学华南先进光电子研究院光及电磁波研究中心

模式复用作为光通信的一个复用维度,最近成为国际上的研究热点.文章综述了最近应用于硅基片上模式复用的相关进展,并介绍了一些核心器件及其性能,如:总线波导、复用/解复用器、光纤接口以及多模光开关等.文章从器件的工作原理,分析比较... 详细信息

模式复用作为光通信的一个复用维度,最近成为国际上的研究热点.文章综述了最近应用于硅基片上模式复用的相关进展,并介绍了一些核心器件及其性能,如:总线波导、复用/解复用器、光纤接口以及多模光开关等.文章从器件的工作原理,分析比较了其性能特点和优缺点,并展望了硅基片上模式复用的发展趋势.

关键词：硅光子学光互连模式复用