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Chiral Frustrated Lewis Pairs Catalyzed Highly Enantioselective Hydrosilylations of Ketones

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Chinese Journal of Chemistry 2019年第7期37卷 663-666页

作者： Xiaoqin Liu qiaotian wang Caifang Han Xiangqing Feng Haifeng Du Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Molecular Recognition and Function CAS Research/Education Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China School of Chemical Science University of Chinese Academy of Sciences Beijing 100049 China

A highly enantioselective Piers-type hydrosilylation of simple ketones was successfully realized using a chiral frustrated Lewis pair of tri-tert-butylphosphine and chiral diene-derived borane as catalyst.A wide range of optically active secondary alcohols were furnished in 80%-99% yields with 81%-97% ee's under mild reaction conditions.

关键词： Enantioselective Hydrosilylations of Ketones

手性螺环骨架硼烷催化酮的不对称硅氢化反应（英文）

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有机化学 2019年第8期39卷 2257-2263页

作者：王桥天韩彩芳冯向青杜海峰中国科学院化学研究所北京国家分子科学研究中心中国科学院分子识别与功能重点实验室北京100190 中国科学院大学北京100049

受阻路易斯酸碱对(frustrated Lewis pairs,FLPs)是目前合成化学的前沿挑战性研究领域之一,为非金属催化的氢化和Piers-type硅氢化反应提供了非常有效的途径.近年来,相关研究取得了重要的研究进展,但是相应的不对称反应发展比较缓慢.缺... 详细信息

受阻路易斯酸碱对(frustrated Lewis pairs,FLPs)是目前合成化学的前沿挑战性研究领域之一,为非金属催化的氢化和Piers-type硅氢化反应提供了非常有效的途径.近年来,相关研究取得了重要的研究进展,但是相应的不对称反应发展比较缓慢.缺乏高效、高选择性的手性催化剂仍然是制约这一领域快速发展的重要因素.手性螺环是配体设计中的优势骨架.基于前期所发展的联萘骨架手性FLP催化剂及其在不对称催化氢化和硅氢化反应的应用,设计并合成了基于手性螺环骨架的手性双烯,通过与HB(C6F5)2的硼氢化反应原位制备了新型手性硼烷路易斯酸.利用其与三叔丁基膦形成的手性受阻路易斯酸碱对催化剂,成功地实现了简单酮的不对称Piers-type硅氢化反应,反应的对映选择性最高可达90%.

关键词：不对称催化不对称硅氢化受阻路易斯酸碱对手性螺二烯酮

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简化角冰冰形对翼型绕流流场结构的影响

Acta Mechanica Sinica 2024年第5期40卷 33-49页

作者：郑诚毅金哲岩杜旭之东乔天杨志刚 School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai China Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems Shanghai China Department of Mechanical Science and Engineering University of Illinois Urbana USA COMAC Shanghai Aircraft Design & Research Institute Shanghai China

机机翼前缘结冰会改变机翼的气动轮廓并影响整体的空气动力学性能.研究简化角冰冰形对翼型绕流流场结构的影响可以为飞机防冰设计提供有价值的参考.采用粒子图像测速技术,在低速直流风洞中对覆盖不同角冰冰形的翼型在不同攻角时的流场... 详细信息

机机翼前缘结冰会改变机翼的气动轮廓并影响整体的空气动力学性能.研究简化角冰冰形对翼型绕流流场结构的影响可以为飞机防冰设计提供有价值的参考.采用粒子图像测速技术,在低速直流风洞中对覆盖不同角冰冰形的翼型在不同攻角时的流场结构进行了详细的实验测量.实验对象包括三种简化的冰形和原始冰形.结果表明,在本研究范围内,覆盖简化冰形的翼型和覆盖原始冰形的翼型在流场参数上的最大差异为35.11%.与原始冰形相比,覆盖简化的角冰冰形的翼型流场中的分离泡距离翼型前缘和后缘更远.在三种冰形简化方法中,将冰角简化成矩形并在冰角之间添加抛物线的连接方式具有比较好的简化效果.在选定的两个区域中,这种简化冰形和原始冰形在翼型绕流流场的参数平均值的差异在14.88%之内.

关键词：机翼前缘流场结构翼型绕流飞机防冰空气动力学性能粒子图像测速技术流场参数直流风洞

广东省龙眼洞林场5G智慧喷淋防灭火林带系统设计

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现代信息科技 2023年第1期7卷 119-122,126页

作者：陈富强何莹泉王巧天郭勇洪维广东省龙眼洞林场广东广州510520 广东省林业调查规划院广东广州510520 广东远景信息科技有限公司广东广州510115

为守护绿水青山,保障森林生态安全,做好森林火灾预防及扑救工作至关重要。合理利用水可有效防治森林火灾,凭借5G通信的超可靠、低时延技术优势,依托物联网技术和智慧控制系统,对龙眼洞林场进行了1 km智慧喷淋防灭火林带设计、建设和试验... 详细信息

为守护绿水青山,保障森林生态安全,做好森林火灾预防及扑救工作至关重要。合理利用水可有效防治森林火灾,凭借5G通信的超可靠、低时延技术优势,依托物联网技术和智慧控制系统,对龙眼洞林场进行了1 km智慧喷淋防灭火林带设计、建设和试验,系统实现了对林火的24h全天候自动监测预防及扑灭。该项试验将水灭火与智能技术相结合,为国有林场等森林防灭火重点地区的防灭火提供了可推广、可借鉴、可复制的参考方案。

关键词： 5G 自动喷淋防灭火林带自动喷淋技术森林智能防灭火

Design of Flexible Films Based on Kinked Carbon Nanofibers for High Rate and Stable Potassium-Ion Storage

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Nano-Micro Letters 2022年第3期14卷 184-200页

作者： qiaotian Xiong Hongcheng He Ming Zhang Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low‑Dimensional Structural Physics&Devices School of Physics and ElectronicsCollege of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082People’s Republic of China Semiconductor Technology and Application Innovation Institute of Changsha Changsha 410012People’s Republic of China

With the emergence of wearable electronics,flexible energy storage materials have been extensively studied in recent ***,most studies focus on improving the electrochemical properties,ignoring the flexible mechanism and structure design for flexible electrode materials with high rate capacities and long-time *** this study,porous,kinked,and entangled network structures are designed for highly flexible fiber *** on theoretical analysis and finite element simulation,the bending degree of the porous structure(30%porosity)increased by 192%at the *** appropriate increase in kinking degree at the meso-level and contact points in entanglement network at the macro-level are beneficial for the flexibility of fiber ***,a porous and entangled network of sulfur-/nitrogen-co-doped kinked carbon nanofibers(S/N-KCNFs)is *** nanofiber films synthesized from melamine as nitrogen sources and segmented vulcanization exhibited a porous,kinked,and entangled network structure,and the stretching degree increased several *** flexible S/N-KCNFs anode delivered a higher rate performance of 270 mAh g−1 at a current density of 2000 mA g−1 and a higher capacity retention rate of 93.3%after 2000 ***,the foldable pouch cell assembled by potassium-ion hybrid supercapacitor operated safely at large-angle bending and showed long-time stability of 88%capacity retention after 4000 *** study provides a new idea and strategy for the flexible structure design of high-performance potassium-ion storage materials.

关键词： Flexible design Finite element simulation Sulfur-/nitrogen-Co-doped Anode Potassium-ion storage

Enabling Multi-Chemisorption Sites on Carbon Nanofibers Cathodes by an In-situ Exfoliation Strategy for High-Performance Zn–Ion Hybrid Capacitors

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Nano-Micro Letters 2022年第7期14卷 1-15页

作者： Hongcheng He Jichun Lian Changmiao Chen qiaotian Xiong Cheng Chao Li Ming Zhang Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and DevicesHunan Joint International Laboratory of Advanced Materials and Technology for Clean EnergySchool of Physics and ElectronicsCollege of Semiconductors(College of Integrated Circuits)Hunan UniversityChangsha 410082People’s Republic of China Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055People’s Republic of China School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006People’s Republic of China

Carbon nanofibers films are typical flexible electrode in the field of energy storage,but their application in Zinc-ion hybrid capacitors(ZIHCs)is limited by the low energy density due to the lack of active adsorption *** this work,an in-situ exfoliation strategy is reported to modulate the chemisorption sites of carbon nanofibers by high pyridine/pyrrole nitrogen doping and carbonyl *** experimental results and theoretical calculations indicate that the highly electronegative pyridine/pyrrole nitrogen dopants can not only greatly reduce the binding energy between carbonyl group and Z n2+by inducing charge delocalization of the carbonyl group,but also promote the adsorption of Zn2+by bonding with the carbonyl group to form N–Zn–O *** from the multiple highly active chemisorption sites generated by the synergy between carbonyl groups and pyridine/pyrrole nitrogen atoms,the resulting carbon nanofibers film cathode displays a high energy density,an ultralong-term lifespan,and excellent capacity reservation under commercial mass loading(14.45 mg cm-2).Particularly,the cathodes can also operate stably in flexible or quasi-solid devices,indicating its application potential in flexible electronic *** work established a universal method to solve the bottleneck problem of insufficient active adsorption sites of carbon-based *** should be changed into Improved.

关键词： Nitrogen doping Carbonyl functionalization Chemisorption sites Flexible Zn-ion hybrid capacitors

An upgraded polymeric composite with interparticle chemical bonding microstructure toward lithium-ion battery separators with enhanced safety and electrochemical performances

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能源化学:英文版 2023年第9期84卷 402-413页

作者： Qian Zhao Ling Ma Ye Xu Xiulong Wu Shuai Jiang qiaotian Zheng Guang Hong Bin He Chen Li wanglai Cen Wenjun Zhou Yan Meng Dan Xiao College of Mechanical Engineering Chengdu UniversityChengdu 610106SichuanChina Institute for Advanced Study Chengdu UniversityChengdu 610106SichuanChina Chongqing Academy of Metrology and Quality Inspection Chongqing 401121China Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu 610065SichuanChina

A composite separator of SiC/PVDF-HFP was synthesized for lithium-ion batteries with high thermal and mechanical *** from the nanoscale,high hardness,and melting point of SiC,SiC/PVDFHFP with highly uniform microstructure was *** polarization caused by barrier penetration was significantly *** to the Si-F bond between SiC and PVDF-HFP,the structural stability has been obviously enhanced,which could suppress the growth of lithium(Li) ***,some 3D reticulated Si nanowires are found on the surface of Li anode,which also greatly inhibit Li dendrites and result in irregular flakes of Li ***,the shrinkage of 6% SiC/PVDF-HFP at 150℃ is only 5%,which is notably lower than those of PVDF-HFP and *** commercial LiFePO_(4) cell assembled with 6% SiC/PVDF-HFP possesses a specific capacity of 157.8 mA h g^(-1) and coulomb efficiency of 98% at 80℃.In addition,the tensile strength and modulus of 6% SiC/PVDF-HFP could reach 14.6 and 562 MPa,*** a small deformation(1000 nm) and strong deformation recovery are obtained under a high additional load(2.3 mN).Compared with PVDF-HFP and Celgard2500,the symmetric Li cell assembled with 6% SiC/PVDF-HFP has not polarized after 900 cycles due to its excellent mechanical *** strategy provides a feasible solution for the composite separator of high-safety batteries with a high temperature and impact resistance.

关键词： SiC PVDF-HFP Composite separator Thermal stability Mechanical stability High safety battery

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上海与汉口的外贸埠际转运

社会科学 2008年第9期 175-186页

作者：唐巧天上海社会科学院历史研究所

上海与汉口两大口岸位于长江黄金水道的一首一尾,两者之间的外贸埠际转运变迁反映出汉口作为内河口岸,虽然独立对外进出口能力一度有所发展,但无法完全摆脱对上海外贸转运的依赖,对比出上海对长江内河口岸和北方沿海口岸间外贸埠际转运... 详细信息

上海与汉口两大口岸位于长江黄金水道的一首一尾,两者之间的外贸埠际转运变迁反映出汉口作为内河口岸,虽然独立对外进出口能力一度有所发展,但无法完全摆脱对上海外贸转运的依赖,对比出上海对长江内河口岸和北方沿海口岸间外贸埠际转运影响力的不同,及长江流域作为上海核心经济腹地的重要性。上海与汉口之间的贸易关系,牵扯着长江流域这一中国经济发展的命脉,其间涉及到的商业经营、金融汇兑、人口流动及城市成长等诸多问题都值得探讨,两大口岸间的埠际贸易研究应继续推向深入。

关键词：埠际贸易内河口岸长江流域

论晚清上海作为全国外贸中心的影响力(1864-1904)——以外贸埠际转运为视角

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中国历史地理论丛 2006年第3期21卷 64-73页

作者：唐巧天复旦大学历史地理研究中心上海200433

作为中国最早开放的通商口岸之一,上海开埠后即迅速跃升为全国对外贸易中心。上海通过与各口岸间的外贸埠际转运,将其外贸影响辐射至大半个中国,显示出其全国外贸中心的地位。本文利用系统的海关数据及文字报告,阐述了晚清上海外贸埠际... 详细信息

作为中国最早开放的通商口岸之一,上海开埠后即迅速跃升为全国对外贸易中心。上海通过与各口岸间的外贸埠际转运,将其外贸影响辐射至大半个中国,显示出其全国外贸中心的地位。本文利用系统的海关数据及文字报告,阐述了晚清上海外贸埠际转运在全国的地位、上海的外贸转运网络及其特点,以此为视角反映出晚清上海作为全国外贸中心的影响力。

关键词：上海全国外贸中心外贸埠际转运