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Regioselective and asymmetric allylic alkylation of vinyl epoxides for the construction of allylic alcohols via synergistic catalysis

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Science China Chemistry 2024年第2期67卷 542-550页

作者： Min Chen Longqing Yang Yuzhen Li Yinhe Qu Guihua pan Xiaoming feng Xiaohua Liu Key Laboratory of Green Chemistry&Technology Ministry of EducationCollege of ChemistrySichuan UniversityChengdu610064China

A highly efficient asymmetric allylic alkylation of cyclic and acyclic carbon nucleophiles with vinyl epoxides has been developed,which exhibits good functional group compatibility,high atomic and step economy.This protocol utilizes a strategy of synergistic catalysis with a chiral N,N'-dioxide/Ni~Ⅱ complex and an achiral Pd~0 catalyst,generating a series of multisubstituted allylic alcohols with a quaternary carbon stereocenter in high yield and excellent regio-,Z/E-and enantioselectivity under mild conditions.Further transformations of the product demonstrate the potential utility of this protocol in the synthesis of allyl alcohol derivatives and natural product analogues.Experimental studies revealed that the N,N′-dioxide/metal complexes play an important role in controlling the Z/E-and enantioselectivity.The density functional theory(DFT) calculations further demonstrated that multiple C–H···π interactions between the aromatic rings of the two substrates and the amide moiety in the ligand stabilized the dominant transition state.

关键词： asymmetric allylic alkylation synergistic catalysis vinyl epoxides allyl alcohol multiple weak interactions

Molybdenum Oxynitride Atomic Nanoclusters Bonded in Nanosheets of N-Doped Carbon Hierarchical Microspheres for Efficient Sodium Storage

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Nano-Micro Letters 2022年第10期14卷 148-163页

作者： Xiaona pan Baojuan Xi Huibing Lu Zhengchunyu Zhang Xuguang An Jie Liu Jinkui feng Shenglin Xiong School of Chemistry and Chemical Engineering State Key Laboratory of Crystal MaterialsShandong UniversityJinan 250100People’s Republic of China School of Mechanical Engineering Chengdu UniversityChengdu 610106People’s Republic of China The State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050People’s Republic of China School of Materials Science and Engineering Shandong UniversityJinan 250100People’s Republic of China

Transition metal nitrides have attracted considerable attention as great potential anode materials due to their excellent metallic conductivity and high theoretical specific capacity.However,their cycling performance is impeded by their instability caused by the reaction mechanism.Herein,we report the engineering and synthesis of a novel hybrid architecture composed of MoO2.0N0.5 atomic nanoclusters bonded in nanosheets of N-doped carbon hierarchical hollow microspheres(MoO2.0N0.5/NC)as an anode material for sodium-ion batteries.The facile self-templating strategy for the synthesis of MoO2.0N0.5/NC involves chemical polymerization and subsequent one-step calcination treatments.The design is benefi-cial to improve the electrochemical kinetics,buffer the volume variation of electrodes during cycling,and provide more interfacial active sites for sodium uptake.Due to these unique structural and compositional merits,these MoO2.0N0.5/NC exhibits excellent sodium storage performance in terms of superior rate capability and stable long cycle life.The work shows a feasible and effective way to design novel host candidates and solve the long-term cycling stability issues for sodium-ion batteries.

关键词： Molybdenum oxynitride Atomic nanocluster Hollow microspheres Sodium-ion batteries

Recycling of waste aluminum scraps to fabricate sulfidated zero-valent iron-aluminum particles for enhanced chromate removal

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Journal of Environmental Sciences 2024年第4期138卷 650-659页

作者： Yahui Zhang Liguo Zhang Jiajia Zeng Shuqun Xu Jianyu pan Wenzhuo Huang Jianliang Sun feng Jiang Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety&MOE Key Laboratory of Theoretical Chemistry of Environment School of EnvironmentSouth China Normal UniversityGuangzhou 510006China Guangdong Provincial Key Lab of Environmental Pollution Control and Remediation Technology School of Environmental Science&EngineeringSun Yat-Sen UniversityGuangzhou 510275China

Massive waste aluminum scraps produced from the spent aluminum products have high electron capacity and can be recycled as an attractive alternative to materials based on zerovalent iron(Fe^(0))for the removal of oxidative contaminants from wastewater.This study thus proposed an approach to fabricate micron-sized sulfidated zero-valent iron-aluminum particles(S-Al^(0)@Fe^(0))with high reactivity,electron selectivity and capacity using recycled waste aluminum scraps.S-Al^(0)@Fe^(0)with a three-layer structure contained zero-valent aluminum(Al^(0))core,Fe^(0) middle layer and iron sulfide(FeS)shell.The rates of chromate(Cr(Ⅵ))removal by S-Al^(0)@Fe^(0)at pH 5.0-9.0 were 1.6-5.9 times greater than that by sulfidated zero-valent iron(S-Fe^(0)).The Cr(Ⅵ)removal capacity of S-Al^(0)@Fe^(0)was 8.2-,11.3-and 46.9-fold greater than those of S-Fe0,zero-valent iron-aluminum(Al^(0)-Fe^(0))and Fe^(0),respectively.The chemical cost of S-Al^(0)@Fe^(0) for the equivalent Cr(Ⅵ)removal was 78.5%lower than that of S-Fe^(0).Negligible release of soluble aluminum during the Cr(Ⅵ)removal was observed.The significant enhancement in the reactivity and capacity of S-Al^(0)@Fe^(0)was partially ascribed to the higher reactivity and electron density of the Al0core than Fe^(0).More importantly,S-Al^(0)@Fe^(0) served as an electric cell to harness the persistent and selective electron transfer from the Al^(0)-Fe^(0) core to Cr(Ⅵ)at the surface via coupling Fe^(0)-Fe^(2+)-Fe^(3+)redox cycles,resulting in a higher electron utilization efficiency.Therefore,S-Al^(0)@Fe^(0) fabricated using recycled waste aluminum scraps can be a cost-effective and environmentally-friendly alternative to S-Fe^(0) for the enhanced removal of oxidative contaminants in industrial wastewater.

关键词： Recycled waste aluminum scraps Oxidative contaminants Cr(Ⅵ)reduction Sulfidated Al^(0)@Fe^(0)particle Electron transfer

Dynamic confinement of SAPO-17 cages on the selectivity control of syngas conversion

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National Science Review 2022年第9期9卷 40-46页

作者： Haodi Wang feng Jiao Yi Ding Wenjuan Liu Zhaochao Xu Xiulian pan Xinhe Bao State Key Laboratory of Catalysis 2011-Collaborative Innovation Center of Chemistry for Energy Materials Dalian Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Chemical Physics University of Science and Technology of China Key Laboratory of Separation Science for Analytical Chemistry Dalian Institute of Chemical Physics Chinese Academy of Sciences

The OXZEO(oxide-zeolite) bifunctional catalyst concept has enabled selective syngas conversion to a series of value-added chemicals and fuels such as light olefins,aromatics and gasoline.Herein we report for the first time a dynamic confinement of SAPO-17 cages on the selectivity control of syngas conversion observed during an induction period.Structured illumination microscopy,intelligent gravimetric analysis,UV-Raman,X-ray diffraction,thermogravimetry and gas chromatography-mass spectrometer analysis indicate that this is attributed to the evolution of carbonaceous species as the reaction proceeds,which gradually reduces the effective space inside the cage.Consequently,the difusion of molecules is hindered and the hindering is much more prominent for larger molecules such as C4+.As a result,the selectivity of ethylene is enhanced whereas that of C4+is suppressed.Beyond the induction period,the product selectivity levels off.For instance, ethylene selectivity levels off at 44% and propylene selectivity at 31 %,as well as CO conversion at 27%.The findings here bring a new fundamental understanding that will guide further development of selective catalysts for olefin synthesis based on the OXZEO concept.

关键词： syngas conversion OXZEO dynamic confinement zeolite diffusion

Double Inverted Pendulum Sliding Mode Variation Structure Control Based on Fractional Order Exponential Approach Law 25th

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Double Inverted Pendulum Sliding Mode Variation Structure Co...

Investigation into the roles of interfacial H_(2)O structure in catalytic oxidation of HCHO and CO over CuMnO_(2) catalysts

第25届中国控制与决策会议

作者： PAN Feng Liu Lu Xue Dingyu School of Information Science ＆ Engineering Northeastern University

ISBN: (纸本)9781467355339

Rotary double inverted pendulum system is a typical nonlinear, much variable, high order and unstable underactuated system. Currently, common sliding mode variable structure control method made system being vibration, long adjusting time and large overshoot, and so on. Aiming at these problems, fractional order improvement is proposed in this paper. Simulating on rotary double inverted pendulum system, the result’s comparison indicates that fractional-order method has obvious superiority, like overshoot decreasing, adjusting time shortening, and vibration weakening. The simulation result provides theory for a hardware-in-loop simulation for rotary double inverted pendulum system.

关键词： Rotary double inverted pendulum Sliding mode variation structure Fractional exponential approach law

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Journal of Environmental Sciences 2024年第3期137卷 310-320页

作者： Chunyan Ma Jushuang pan Cheng Chen Yuanyuan Dong feng Yao fengbang Wang Maoyong Song Key Laboratory of Environmental Nanotechnology and Health Effects Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China No.52 Institute of China North Industries Group Yantai Branch Co.Ltd. Yantai 264000China

The rapid deactivation of cost-effective MnO_(2)-based catalysts in humid air limits their application in practice,and the identification of the role of water in an oxidation process is significant for developing water-resistant MnO_(2)-based catalysts.Here,CuMnO_(2)showed a20.3%HCHO conversion in 10 hr at room temperature in humid air with relative humidity of 40%,but deactivated in 3 hr in dry air.The excellent activity and stability of HCHO oxidation in humid air were attributed to the positive effect of H_(2)O on HCHO oxidation to the H_(2)O-HOCH_(2)OH supermolecule assemblies via hydrogen bonds formed on CuMnO_(2).H_(2)O-HOCH_(2)OH supermolecule assemblies tend to be oxidized to carbonate,which is further oxidized to CO_(2).Furthermore,CuMnO_(2)exhibited a much poorer activity of CO oxidation in humid air,but the CO conversion was still 100%in 10 hr in dry air.H_(2)O showed a competitive adsorption effect to CO on CuMnO_(2).CuMnO_(2)could be applied in HCHO elimination in humid air and CO elimination in dry air.

关键词： H_(2)O-HOCH_(2)OH supermolecule HCHO oxidation Humid air CuMnO_(2) CO oxidation

Novel Door-opening Method for Six-legged Robots Based on Only Force Sensing

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Chinese Journal of Mechanical Engineering 2017年第5期30卷 1227-1238页

作者： Zhi-Jun Chen feng Gao Yang pan State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai GQY Robot Limited Company

Current door-opening methods are mainly developed on tracked, wheeled and biped robots by applying multi-DOF manipulators and vision systems. However, door-opening methods for six-legged robots are seldom studied, especially using 0-DOF tools to operate and only force sensing to detect. A novel door-opening method for six-legged robots is developed and imple- mented to the six-parallel-legged robot. The kinematic model of the six-parallel-legged robot is established and the model of measuring the positional relationship between the robot and the door is proposed. The measurement model is completely based on only force sensing. The real- time trajectory planning method and the control strategy are designed. The trajectory planning method allows the maximum angle between the sagittal axis of the robot body and the normal line of the door plane to be 45°. A 0-DOF tool mounted to the robot body is applied to operate. By integrating with the body, the tool has 6 DOFs and enough workspace to operate. The loose grasp achieved by the tool helps release the inner force in the tool. Experiments are carried out to validate the method. The results show that the method is effective and robust in opening doors wider than 1 m. This paper proposes a novel door-opening method for six-legged robots, which notably uses a O-DOF tool and only force sensing to detect and open the door.

关键词： Door-opening·Six-legged robots· Forcesensing · O-DOF tool

Quantifying both climate and land use/cover changes on runoff variation in Han River basin, China

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Frontiers of Earth Science 2022年第3期16卷 711-733页

作者： Jing TIAN Shenglian GUO Jiabo YIN Zhengke pan feng XIONG Shaokun HE State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Changjiang Institute of Survey PlanningDesign and ResearchWuhan 430010China Bureau of Hydrology Changjiang Water Resources CommissionWuhan 430010China

Climate change and land use/cover change(LUCC)can both exert great impacts on the generation processes of precipitation and runoff.However,previous studies usually neglected considering the contribution component of future LUCC in evaluating changes in hydrological cycles.In this study,an integrated framework is developed to quantify and partition the impact of climate change and LUCC on future runoff evolution.First,a daily bias correction(DBC)method and the Cellular Automaton-Markov(CA-Markov)model are used to project future climate and LUCC scenarios,and then future runoff is simulated by the calibrated Soil and Water Assessment Tool(SWAT)model with different climate and LUCC scenarios.Finally,the uncertainty of future runoff and the contribution rate of the two driving factors are systematically quantified.The Han River basin in China was selected as a case study.Results indicate that:1)both climate change and LUCC will contribute to future runoff intensification,the variation of future runoff under combined climate and LUCC is larger than these under climate change or LUCC alone;2)the projected uncertainty of median value of multi-models under RCP4.5(RCP8.5)will reach 18.14%(20.34%),12.18%(14.71%),11.01%(13.95%),and 11.41%(14.34%)at Baihe,Ankang,Danjiangkou,and Huangzhuang stations,respectively;3)the contribution rate of climate change to runoff at Baihe,Ankang,Danjiangkou,and Huangzhuang stations under RCP4.5(RCP8.5)are 91%-98%(84%-94%),while LUCC to runoff under RCP4.5(RCP8.5)only accounts for 2%-9%(6%-16%)in the annual scale.This study may provide useful adaptive strategies for policymakers on future water resources planning and management.

关键词： climate change LUCC runoff response uncertainty analysis contribution rate

Successful treatment of acute carotid artery injuries

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World Journal of Emergency Medicine 2023年第1期14卷 65-68页

作者： Yi-feng pan Zhen-jie Liu Li-bin Zhang Zhi-wei Gao Bing Chen Department of Vascular Surgery the Second Affiliated Hospital of Zhejiang University School of MedicineHangzhou 310009China

Vascular injuries can lead to severe consequences, and in particular, carotid artery injury caused by combat, traffic accidents or other external forces is extremely harmful. As the neck has a complex anatomical structure and a relatively small local space, carotid artery injury is usually complicated by neural and spinal injuries.

关键词： injuries carotid artery