检索结果-南通市图书馆

A copper-catalyzed three-component reaction of alkenes,cycloketone oximes and DABCO·(SO_(2))_(2):Direct C(sp^(2))-H cyanoalkylsulfonylation

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2022年第5期33卷 2383-2386页

作者： Yating Liu Luoyu Wang Ling-Hui Zeng Yun Zhao tonghao zhu Jie Wu School of Pharmaceutical and Chemical Engineering&Institute for Advanced Studies Taizhou UniversityTaizhou 318000China Department of Pharmacology Zhejiang University City CollegeHangzhou 310015China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007China

A copper-catalyzed three-component reaction of alkenes,cycloketone oximes and DABCO·(SO_(2))_(2) is de-veloped,which provides a convenient route for the synthesis of diverse(E)-cyanoalkylsulfonyl alkenes in moderate to good yields with excellent regio-and stereoselectivity.A broad substrate scope with ex-cellent functional group tolerance is observed.A plausible radical pathway is proposed,which involves copper-catalyzed ring-opening C–C bond cleavage of O-acyl oxime and insertion of sulfur *** the reaction process,cyanoalkyl radical and cyanoalkylsulfonyl radical are the key intermediates.

关键词： Copper iodide Sulfur dioxide C-C bond cleavage C(sp^(2))-H Cyanoalkylsulfonylation Radical process

Regio- and （E）-Stereoselective Triborylation of Propargylic Carbonates

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2017年第8期35卷 1251-1262页

作者： Zheng Yang Tao Cao Yulin Han Weilong Lin Qi Liu Yang Tang Yizhan Zhai Minqiang Jia Wanli Zhang tonghao zhu Shengming Ma State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Lingling Lu Shanghai 200032 China University of Chinese Academy of Sciences Beijing 100049 China Department of Chemistry Fudan University 220 Handan Lu Shanghai 200433 China

An efficient synthesis of （E）-alken-1,2,3-triboronates form readily available propargylic carbonates is described. The reaction enjoys excellent regio- and E-selectivity and many synthetically useful functional groups can be tolerated. Based on mechanistic studies, a two-step mechanism via 1,2-allenyl boronate intermediate is proposed.

关键词： palladium copper propargylic carbonate triborylation

采空区复合灾害环境下含瓦斯煤自燃特征研究进展

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

煤炭学报 2024年第6期49卷 2711-2727页

作者：田富超贾东旭陈明义梁运涛朱红青张同浩中煤科工集团沈阳研究院有限公司煤矿灾害防控全国重点实验室辽宁沈抚示范区113122 煤炭科学研究总院北京100013 石家庄铁道大学安全工程与应急管理学院河北石家庄050043 中国矿业大学(北京)应急管理与安全工程学院北京100083

采空区瓦斯与煤自燃复合灾害日趋成为制约矿井安全生产的主要灾害模式,煤自燃作为瓦斯燃烧、爆炸等灾害事故的“点火源”,无疑是防范煤矿采空区复合灾害的关键。目前关于采空区遗煤残余瓦斯(吸附态为主)与风流瓦斯(游离态)对煤自燃影响... 详细信息

采空区瓦斯与煤自燃复合灾害日趋成为制约矿井安全生产的主要灾害模式,煤自燃作为瓦斯燃烧、爆炸等灾害事故的“点火源”,无疑是防范煤矿采空区复合灾害的关键。目前关于采空区遗煤残余瓦斯(吸附态为主)与风流瓦斯(游离态)对煤自燃影响机理的认识还不够深入,为此探究了含瓦斯条件下煤自燃相关研究的最新进展。现阶段针对含瓦斯风流/气氛下煤自燃特性的研究内容较为丰富,但吸附态瓦斯影响条件下的煤自燃特性实验平台及相关研究成果较匮乏。研究表明,游离瓦斯易引起煤低温氧化气体产物出现明显的“滞后效应”,同时煤体放热强度减弱、活化能整体增大,这反映出氧化气氛中的瓦斯对煤自燃具有抑制作用;相应地,煤自燃过程中的官能团、自由基及煤微晶结构等微观特征参数均会随瓦斯体积分数呈现规律性演变。进一步,考虑到遗煤内部残余瓦斯与风流瓦斯的赋存状态差异,探究了瓦斯对煤自燃过程的影响机理,包括CH4对O_(2)的驱替稀释作用、CH_(4)与O_(2)的竞争吸附解吸引起的置换效应,以及高温环境下的O_(2)分子化学吸附和煤氧复合效应作用。基于此,提出了采空区遗煤在吸附态瓦斯影响下的自燃过程特性、含瓦斯煤自燃流–固–热–化多场耦合特征、含瓦斯煤自燃监测预警理论应用等亟待突破的瓶颈问题。

关键词：煤自燃复合灾害环境微观特征多场耦合遗煤残余瓦斯热动力灾害

Direct field-to-pattern monolithic design of holographic metasurface via residual encoderdecoder convolutional neural network

在线全文

学校读者我要写书评

暂无评论

Opto-Electronic Advances 2023年第8期6卷 29-38页

作者： Ruichao zhu Jiafu Wang Tianshuo Qiu Dingkang Yang Bo Feng Zuntian Chu tonghao Liu Yajuan Han Hongya Chen Shaobo Qu Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices Air Force Engineering UniversityXi'an 710051China The Academy for Engineering&Technology Fudan UniversityShanghai 200433China

Complex-amplitude holographic metasurfaces(CAHMs)with the flexibility in modulating phase and amplitude profiles have been used to manipulate the propagation of wavefront with an unprecedented level,leading to higher image-reconstruction quality compared with their natural ***,prevailing design methods of CAHMs are based on Huygens-Fresnel theory,meta-atom optimization,numerical simulation and experimental verification,which results in a consumption of computing ***,we applied residual encoder-decoder convolutional neural network to directly map the electric field distributions and input images for monolithic metasurface design.A pretrained network is firstly trained by the electric field distributions calculated by diffraction theory,which is subsequently migrated as transfer learning framework to map the simulated electric field distributions and input *** training results show that the normalized mean pixel error is about 3%on *** verification,the metasurface prototypes are fabricated,simulated and *** reconstructed electric field of reverse-engineered metasurface exhibits high similarity to the target electric field,which demonstrates the effectiveness of our ***,this work provides a monolithic field-to-pattern design method for CAHMs,which paves a new route for the direct reconstruction of metasurfaces.

关键词： metasurface holography complex amplitude deep learning monolithic design

Six-channel programmable coding metasurface simultaneously for orthogonal circular and linear polarizations

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2023年第6期11卷 1047-1056页

作者： tonghao LIU YUEYU MENG JIAFU WANG HUA MA RUICHAO zhu CHAO LIU WEIHAN LI ZUNTIAN CHU SAI SUI TIANSHUO QIU WENXUAN TANG SHAOBO QU Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices Air Force Engineering UniversityXi’an 710051China State Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China Frontiers Science Center for Mobile Information Communication and Security Southeast UniversityNanjing 210096China

Metasurfaces have intrigued long-standing research interests and developed multitudinous compelling applications owing to their unprecedented capability for manipulating electromagnetic waves,and the emerging programmable coding metasurfaces(PCMs)provide a real-time reconfigurable platform to dynamically implement customized ***,most existing PCMs can only act on the single polarization state or perform in the limited polarization channel,which immensely restricts their practical application in multitask intelligent ***,an appealing strategy of the PCM is proposed to realize tunable functions in co-polarized reflection channels of orthogonal circularly polarized waves and in co-polarized and cross-polarized reflection channels of orthogonal linearly polarized waves from 9.0 to 10.5 *** the above six channels,the spindecoupled programmable meta-atom can achieve high-efficiency reflection and 1-bit digital phase modulation by selecting the specific ON/OFF states of two diodes,and the phase coding sequence of the PCM is dynamically regulated by the field-programmable gate array to generate the desired function.A proof-of-concept prototype is constructed to verify the feasibility of our methodology,and numerous simulation and experimental results are in excellent agreement with the theoretical *** inspiring design opens a new avenue for constructing intelligent metasurfaces with higher serviceability and flexibility,and has tremendous application potential in communication,sensing,and other multifunctional smart metadevices.

关键词： polarization channel polarized

Machine-learning-empowered multispectral metafilm with reduced radar cross section,low infrared emissivity,and visible transparency

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2022年第5期10卷 1146-1156页

作者： RUICHAO zhu JIAFU WANG JINMING JIANG CUILIAN XU CHE LIU YUXIANG JIA SAI SUI ZHONGTAO ZHANG tonghao LIU ZUNTIAN CHU JUN WANG TIE JUN CUI SHAOBO QU Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices Air Force Engineering UniversityXi’an 710051China Institute of Electromagnetic Space Southeast UniversityNanjing 210096China State Key Laboratory of Millimeter Wave Southeast UniversityNanjing 210096China

For camouflage applications,the performance requirements for metamaterials in different electromagnetic spectra are usually contradictory,which makes it difficult to develop satisfactory design schemes with multispectral ***,empowered by machine learning,metamaterial design is no longer limited to directly solving Maxwell’s *** design schemes and experiences of metamaterials can be analyzed,summarized,and learned by computers,which will significantly improve the design efficiency for the sake of practical engineer-ing ***,we resort to the machine learning to solve the multispectral compatibility problem of metamaterials and demonstrate the design of a new metafilm with multiple mechanisms that can realize small microwave scattering,low infrared emissivity,and visible transparency simultaneously using a multilayer back-propagation neural *** rapid evolution of structural design is realized by establishing a mapping between spectral curves and structural *** training the network with different materials,the designed network is more *** simulations and experimental verifications,the designed architecture has good accuracy and *** paper provides a facile method for fast designs of multispectral metafilms that can find wide applications in satellite solar panels,aircraft windows,and others.

关键词： transparency visible film

Virtual metasurfaces:reshaping electromagnetic waves in distance

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2023年第2期11卷 203-211页

作者： RUICHAO zhu JIAFU WANG YAJUAN HAN YUXIANG JIA tonghao LIU TIANSHUO QIU SAI SUI YONGFENG LI MINGBAO YAN SHAOBO QU CHENG-WEI QIU Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices Air Force Engineering UniversityXi’an 710051China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore NUS Suzhou Research Institute(NUSRI) Suzhou 215000China

Metasurface has provided unprecedented freedoms in manipulating electromagnetic(EM) waves, exhibiting fascinating functions. Conventionally, these functions are implemented right on metasurfaces, where spatial modulations on EM wave amplitudes or phases are achieved by meta-atoms. This study proposes the concept of virtual metasurface(VM), which is formed by arrays of foci away from the entity metasurface. Unlike conventional metasurfaces, spatial modulations on the amplitudes or phases of EM waves occur in the air, with a focal length distance from the entity metasurface. As a proof of concept, we demonstrated a transmissive VM. The entity metasurface consists of transmissive focusing metasurface tiles(TFMTs) with the same focal length. Two TFMTs were designed with phase difference π to enable the most typical checkerboard configuration. The TFMTs were assembled to form the entity metasurface, whereas their foci formed the VM. Due to the π phase difference among adjacent foci, EM propagation along the normal direction was cancelled, leading to four tilted far-field beams. The concept of VM can be readily extended to higher frequencies from terahertz to optical regimes and may find wide applications in communication, camouflage, and other fields.

关键词： surface. surfaces proof

Remotely mind-controlled metasurface via brainwaves

在线全文

学校读者我要写书评

暂无评论

eLight 2022年第1期2卷 121-131页

作者： Ruichao zhu Jiafu Wang Tianshuo Qiu Yajuan Han Xinmin Fu Yuzhi Shi Xingsi Liu tonghao Liu Zhongtao Zhang Zuntian Chu Cheng‑Wei Qiu Shaobo Qu Shaanxi Key Laboratory of Artificially‑Structured Functional Materials and Devices Air Force Engineering UniversityXi’an 710051ShaanxiChina National Key Laboratory of Science and Technology on Micro/Nano Fabrication Department of Micro/Nano ElectronicsShanghai Jiao Tong UniversityShanghai 200240China Department of Electrical and Computer Engineering Faculty of EngineeringNational University of Singapore4 Engineering Drive 3Singapore 117583Singapore

The power of controlling objects with mind has captivated a popular fascination to human *** possible path is to employ brain signal collecting technologies together with emerging programmable metasurfaces(PM),whose functions or operating modes can be switched or customized via on-site programming or pre-defined ***,most of existing PMs are wire-connected to users,manually-controlled and not ***,we propose the concept of remotely mind-controlled metasurface(RMCM)via *** than DC voltage from power supply or AC voltages from signal generators,the metasurface is controlled by brainwaves collected in real time and transmitted wirelessly from the *** an example,we demonstrated a RMCM whose scattering pattern can be altered dynamically according to the user’s brain waves via *** attention intensity information is extracted as the control signal and a mapping between attention intensity and scattering pattern of the metasurface is *** such a framework,we experimentally demonstrated and verified a prototype of such metasurface system which can be remotely controlled by the user to modify its scattering *** work paves a new way to intelligent metasurfaces and may find applications in health monitoring,5G/6G communications,smart sensors,etc.

关键词： Brainwave Mind-controlled Reprogrammable metasurface Intelligent metasurface

Cu/ZSM-5催化剂的表征及其环己醇脱氢性能

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

石油化工 2007年第6期36卷 570-574页

作者：吉定豪朱万春吴通好王振旅王国甲吉林大学化学学院吉林长春130023

以制备的ZSM-5分子筛为载体,采用浸渍法制备了一系列Cu负载量不同的Cu/ZSM-5催化剂。采用X射线衍射、氢气程序升温还原、吸附氨气程序升温脱附和BET等方法对Cu/ZSM-5催化剂进行了表征,用H2-N2O滴定法测定了Cu金属的比表面积和分散度。... 详细信息

以制备的ZSM-5分子筛为载体,采用浸渍法制备了一系列Cu负载量不同的Cu/ZSM-5催化剂。采用X射线衍射、氢气程序升温还原、吸附氨气程序升温脱附和BET等方法对Cu/ZSM-5催化剂进行了表征,用H2-N2O滴定法测定了Cu金属的比表面积和分散度。以环己醇气相脱氢制备环己酮为探针反应对Cu/ZSM-5催化剂的催化性能进行了评价。实验结果表明,Cu负载量影响Cu物种在载体表面的状态和分布,Cu是环己醇脱氢反应的活性中心,其比表面积、分散度与Cu/ZSM-5催化剂的活性相关,Cu/ZSM-5催化剂的B酸中心与环己醇脱氢反应的选择性相关。Cu质量分数5%的Cu/ZSM-5催化剂上Cu金属的比表面积较大而B酸中心较少,显示出很高的环己醇转化率(58.7%)和较好的环己酮选择性(97.2%)。

关键词：铜/ZSM-5催化剂环己醇脱氢环己酮