检索结果-南通市图书馆

Imidodiphosphorimidates (IDPis): Catalyst Motifs with Unprecedented Reactivity and Selectivity

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2023年第6期41卷 685-694页

作者： jun Kee Cheng shao-Hua Xiang Bin Tan Shenzhen Grubbs Institute and Department of Chemistry Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhenGuangdong 518055China Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhenGuangdong 518055China

The conceptually designed imidodiphosphorimidates(IDPis)have emerged as one of the most potent classes of chiral acid *** are characterized by enzyme-like,highly confined active site and high acidity,which underlie their wide-reaching applications as Bronsted acid catalysts and as precatalysts for silylium Lewis *** carbon-carbon and carbon-heteroatom bond formation reactions that were deemed intractable could now be attained with spectacular reactivity and *** that are small,unbiased and/or possess insufficient reactivity such as simple alkenes could now be *** high structural confinement is particularly invaluable to control stereo-and *** well-defined steric environment offers unique opportunity to control high-energy but structurally unbiased cation intermediates such as the norbonyl *** practical appeals such as good scalability as well as ease and modularity of preparation,the extremely low pre-catalyst loadings required to achieve high turnover and stereoselectivity have also come to define a new frontier in organocatalysis.

关键词： Bronsted acid catalyst Lewis acid catalyst Silylium ACDC Imidodiphosphorimidates Asymmetric organocatalysis

Cu_2ZnSnS_4 thin films prepared by sulfurization of ion beam sputtered precursor and their electrical and optical properties

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

Rare Metals 2006年第z1期25卷 315-319页

作者： ZHANG jun shao Lexi FU Yujun XIE Erqing School of Physics Science and Technology Zhanjiang Normal University Zhanjiang 524048 China School of Physics Science and Technology Lanzhou University Lanzhou 730000 China School of Physics Science and Technology Zhanjiang Normal University Zhanjiang 524048 China School of Physics Science and Technology Lanzhou University Lanzhou 730000 China School of Physics Science and Technology Lanzhou University Lanzhou 730000 China

Cu2ZnSnS4 (CZTS) thin films were successfully prepared by sulfurization of ion bean sputtered precursors on soda-lime glass substrate. The single phase of stannite-type structure CZTS films were obtained as revealed in EDS and XRD analysis when the ratios of the constituents of CZTS thin films are close to stoichiometric by optimizing the conditions of precursor preparation and sulfurization. A low sheet resistivity as about 0.156 Ω·cm and a high absorption coefficient as 1×104 cm-1 were achieved in this method by Hall effect measurements and UV-VIS spectrophotometer. The optical band-gap energy of the CZTS sample is about 1.51 eV, which is very close to the optimum value for a solar-cell absorber.

关键词： Cu2ZnSnS4 thin film solar-cell ion beam sputtering

基于CiteSpace的乡村旅游研究可视化分析

在线全文

学校读者我要写书评

暂无评论

辽宁农业科学 2025年第1期 46-50页

作者：刘钰敏王少俊河海大学公共管理学院江苏南京211100

采用CiteSpace软件对CSSCI数据库中2014~2024年的1 213篇乡村旅游领域文献进行分析,并阐述了该领域的年发文量趋势、核心作者与机构发文特征、研究热点及趋势。研究结果显示,近10年来我国乡村旅游研究的文献年发文量总体呈持续上升趋势... 详细信息

采用CiteSpace软件对CSSCI数据库中2014~2024年的1 213篇乡村旅游领域文献进行分析,并阐述了该领域的年发文量趋势、核心作者与机构发文特征、研究热点及趋势。研究结果显示,近10年来我国乡村旅游研究的文献年发文量总体呈持续上升趋势,预计未来可能因政策关注度降低而有所回落。核心作者群体联系紧密,而其他作者间合作较少。发文机构合作网络呈现出以核心机构为中心,多节点广泛参与的良好态势。研究热点包括精准扶贫、乡村振兴、文旅融合,未来乡村旅游研究将集中在产业融合、高质量发展、共同富裕3个方面。

关键词：乡村旅游 CiteSpace 研究热点

Wind induced deformation and vibration of a Platanus acerifolia leaf

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第3期28卷 583-594页

作者： Chuan-Ping shao Ye-jun Chen Jian-Zhong Lin China Jiliang University 310018 HangzhouChina

Deformation and vibration of twig-connected sin- gle leaf in wind is investigated experimentally. Results show that the Reynolds number based on wind speed and length of leaf blade is a key parameter to the aerodynamic prob- lem. In case the front surface facing the wind and with an in- crease of Reynolds number, the leaf experiences static defor- mation, large amplitude and low frequency sway, reconfigu- ration to delta wing shape, flapping of tips, high frequency vibration of whole leaf blade, recovery of delta wing shape, and twig-leaf coupling vibration. Abrupt changes from one state to another occur at critical Reynolds numbers. In case the back surface facing the wind, the large amplitude and low frequency sway does not occur, the recovered delta wing shape is replaced by a conic shape, and the critical Reynolds numbers of vibrations are higher than the ones correspond- ing to the case with the front surface facing the wind. A pair of ram-horn vortex is observed behind the delta wing shaped leaf. A single vortex is found downstream of the conic shaped leaf. A lift is induced by the vortex, and this lift helps leaf to adjust position and posture, stabilize blade distortion and reduce drag and vibration.

关键词： Tree leaf. Wind. Deformation Vibration

ROCK INITIATION AND PROPAGATION SIMULATION UNDER COMPRESSION-SHEAR LOADING USING CONTINUOUS-DISCONTINUOUS CELLULAR AUTOMATON METHOD

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2015年第4期28卷 384-399页

作者： Fei Yan Xiating Feng Pengzhi Pan shao jun Li State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences

A continuous-discontinuous cellular automaton method is developed for rock initiation and propagation simulations, in which the level set method, discontinuous enrichment shape functions and discontinuous cellular automaton are combined. No renmshing is needed for crack growth analysis, and all calculations are restricted to cells without an assembled global stiffness matrix. The frictional contact theory is employed to construct the contact model of normal pressure and tangential shear on crack surfaces. A discontinuous cellular automaton updating rule suitable for frictional contact of rock is proposed simultaneously with Newton＇s iteration method for nonlinear iteration. Besides, a comprehensive fracturing criterion for brittle rock under compression-shear loading is developed. The accuracy and effectivenesss of the proposed method is proved by numerical simulation.

关键词： continuous-discontinuous cellular automaton method rock fracturing process compressionshear loading frictional contact comprehensive fracturing criterion

Optimization of equimolar reverse constant-temperature mass-diffusion process for minimum entransy dissipation

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2016年第12期59卷 1867-1873页

作者： XIA shao jun CHEN Lin Gen SUN Feng Rui Institute of Thermal Science and Power Engineering Naval University of Engineering Military Key Laboratory for Naval Ship Power Engineering Naval University of Engineering College of Power Engineering Naval University of Engineering

The mass entransy describes the mass-diffusion ability of the solution system, and the mass-diffusion process with the finite concentration difference always leads to the mass-entransy dissipation. This paper studies the equimolar reverse constant-temperature mass-diffusion process with Fick's law( g∝Δ(c)). The optimal concentration paths for the MED(Minimum Entransy Dissipation) are derived and compared with those for the MEG(Minimum Entropy Generation) and CCR(Constant Concentration Ratio) operations. It is indicated that the strategy of the MED is equivalent to that of the CCD(Constant Concentration Difference) of the same component; whether the MED or the MEG is selected as the optimization objective, the strategy of the CCD is much better than that of the CCR.

关键词： mass entransy finite time thermodynamics equimolar reverse mass-diffusion Fick's mass-diffusion law optimal concentration path generalized thermodynamic optimization

Computer Vision-based Navigation and Predefined Track Following Control of a Small Robotic Airship

在线全文

学校读者我要写书评

暂无评论

自动化学报 2007年第3期33卷 286-291页

作者： XIE shao-Rong LUO jun RAO jin-jun GONG Zhen-Bang School of Mechatronics Engineering and Automation ShanghaiUniversity Shanghai 200072 P. R. China

为小机器的飞艇，飞艇应该能够跟随一条预定义的轨道，这被要求。在这份报纸，计算机为机器的飞艇的基于视觉的航行和最佳的模糊控制策略被建议。第一，视觉航行基于环境的自然里程碑被介绍。例如，当飞艇在一个城市上正在飞时，大楼能... 详细信息

为小机器的飞艇，飞艇应该能够跟随一条预定义的轨道，这被要求。在这份报纸，计算机为机器的飞艇的基于视觉的航行和最佳的模糊控制策略被建议。第一，视觉航行基于环境的自然里程碑被介绍。例如，当飞艇在一个城市上正在飞时，大楼能被用作其几何性质从数字地图或一个地理信息系统(GIS ) 被知道的视觉烽火。然后，几何方法论被采用关于飞艇的取向和位置提取信息。以便在一个预定义的磁道上保留飞艇，一个模糊飞行控制系统被设计，它把那些数据用作它的输入。并且基因算法(气体) ，一个通用全球优化方法，被利用优化模糊控制器的会员功能。最后，航行和控制策略被验证。

关键词：自动化系统飞行系统智能机器人宇宙飞船

Deposition of thin TiO_(2)films on fluorophlogopite particle surface by CVD in fluidized bed reactor to prepare silver pearlescent pigments

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第6期89卷 88-98页

作者： Ming Liu Guoqiang shao Pengpeng Lv jun Li Qingshan Zhu State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Two critical parameters:Glossiness and chromaticity space of pearlescent pigments were evaluated based on crystallinity and grain *** the roughness and the vertical distance evolution along the surface of deposited TiO_(2)film are affected by the *** optimal crystallinity of TiO_(2)was deposited at the temperature of 350℃.The TiCl4 concentration effectively changed the grain ***,the high flow rate of fluidizing gas and optimal gas–solid ratio(<0.11 m^(3)/(kg h))restricted the change of TiCl_(4)concentrations in fluidized bed *** this case,the grain size of the deposited TiO_(2)film was about 55 *** on the grain size,the color of pearlescent pigments was adjusted by controlling the film thickness based on TiO_(2)***,the silver pearlescent pigment with high glossiness was prepared by chemical vapor deposition method in a fluidized bed reactor.

关键词： Fluidized bed chemical vapor deposition TiO_(2)film deposition Pearlescent pigment Free powder restrain Crystal growth

A top–down strategy to realize the synthesis of small-sized L10 - platinum-based intermetallic compounds for selective hydrogenation

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

Nano Research 2022年第10期15卷 9631-9638页

作者： Yu jin Guomian Ren Yonggang Feng Shize Geng Ling Li Xing Zhu jun Guo Qi shao Yong Xu Xiaoqing Huang Jianmei Lu College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China Guangzhou Key Laboratory of Low-Dimensional Materials and Energy Storage Devices Collaborative Innovation Center of Advanced Energy MaterialsSchool of Materials and EnergyGuangdong University of TechnologyGuangzhou 510006China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Testing&Analysis Center Soochow UniversitySuzhou 215123China

The synthesis of Pt-based nanoparticles(NPs)with ultrasmall feature and tailored structure is of great importance for catalysis yet *** this work,we demonstrate a facile top–down strategy for the fabrication of small-sized Pt-based intermetallic compounds(IMCs)with L10 structure through the evaporation of Cd under high ***,such thermal treatment can be used as a versatile strategy for creating binary,ternary,quaternary,quinary,and senary L10-Pt-based ***,the small-sized Pt-based IMCs display high stability against high temperature of 700℃,which can serve as active and selective catalyst for the selective hydrogenation of *** work may not only provide a versatile top–down strategy for fabricating highly stable small-sized Pt-based NPs with L10 structure,but also promote their extensive applications in catalysis and beyond.

关键词： top-down strategy Pt-based intermetallic compound small-sized selective hydrogenation