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Visible light-mediated C—P bond formation reactions

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Science Bulletin 2019年第5期64卷 337-350页

作者： Bao-Gui cai jun Xuan Wen-Jing Xiao Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials College of Chemistry & Chemical Engineering Anhui University Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry Central China Normal University

Organophosphorus compounds have attracted continuous attention in materials science, agrochemical and pharmaceutical fields due to their unique bioactivities. Thus, the development of novel and robust manners for the construction new C—P bond has therefore gained great interests in synthetic organic chemistry. Because of their intrinsic sustainability and green chemistry character, visible light-induced photoredox catalysis has been widely applied in the construction of new chemical bonds, including the formation of C—P bond. In this review, we summarized recent achievements in C—P bond formation reactions initiated by visible light-induced photoredox catalysis, which mainly focusing on the discussion of reaction design and the mechanism.

关键词： C-P bond formation Organophosphorus compounds Photoredox catalysis Visible light

Simulation of Heat Transfer with the Growth and Collapse of a Cavitation Bubble Near the Heated Wall

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Journal of Thermal Science 2013年第4期22卷 352-358页

作者： Bin Liu jun cai Fengchao Li Xiulan Huai Institute of Engineering Thermophysics Chinese Academy of Sciences University of Chinese Academy of Sciences

The growth and collapse behaviors of a single cavitation bubble near a heated wail and its effect on the heat transfer are numerically investigated. The present study is designed to reveal the mechanism of cavitation enhanced heat transfer from a microscopic perspective. In the simulation, the time-dependent Navier-Stokes equations are solved in an axisymmetric two-dimensional domain. The volume of fluid （VOF） method is employed to track the liquid-gas interface. It is assumed that the gas inside the bubble is compressible vapor, and the sur- rounding liquid is incompressible water. Mass transfer between two phases is ignored. The eaiculated bubble pro-files were compared to the available experimental data, and a good agreement was obtained. Then, the relationship among bubble motion, flow field and surface heat transfer coefficient was analyzed. On this basis, the effects of such factors as the initial distance between the bubble and the wall, the initial vapor pressure and the initial bubble nucleus size on the heat transfer enhancement are discussed. The present study is helpful to understand the heat transfer phenomenon in presence of cavitation bubble in liquid.

关键词： cavitation bubble bubble growth bubble collapse heat transfer enhancement

New Matrix Lie Algebra, a Powerful Tool for Constructing Multi-component C-KdV Equation Hierarchy

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Communications in Theoretical Physics 2006年第4期45卷 587-592页

作者： YU Fa-jun ZHANG Hong-qing Department of Applied Mathematics Dalian University of Technology Dalian 116024 China

A set of new multi-component matrix Lie algebra is constructed, which is devoted to obtaining a new loop algebra A^-2M. It follows that an isospectral problem is established. By making use of Tu scheme, a Liouville integrable multi-component hicrarchy of soliton equations is generated, which possesses the *** Hamiltonian structures. As its reduction cases, the multi-component C-KdV hierarchy is given. Finally, the *** integrable coupling system of C-KdV hierarchy is presented through enlarging matrix spectral problem.

关键词： matrix Lie algebra Liouville integrable integrable coupling

Ultrafast shape change and joining of small-volume materials using nanoscale electrical discharge

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Nano Research 2015年第7期8卷 2143-2151页

作者： Cheng-cai Wang qing-Jie Li Liang Chen Yong-Hong Cheng jun Sun ZhioWei Shan Ju Li Evan Ma Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano) & Hysitron Applied Research Center in China (HARCC) State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'an 710049 China Department of Nuclear Science and Engineering and Department of Materials Science and Engineering Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge Massachusetts 02139 USA Department of Materials Science and Engineering Johns Hopkins University Baltimore Maryland 21218 USA SJS Limited 101 Xihuan Road Jingzhou Hubei 434024 China

Using nanoscale electrical-discharge-induced rapid Joule heating, we developed a method for ultrafast shape change and joining of small-volume materials. Shape change is dominated by surface-tension-driven convection in the transient liquid melt, giving an extremely high strain rate of N106 s-1. In addition, the heat can be dissipated in small volumes within a few microseconds through thermal conduction, quenching the melt back to the solid state with cooling rates up to 108 K.s-1. We demonstrate that this approach can be utilized for the ultrafast welding of small-volume crystalline Mo （a refractory metal） and amorphous Cu49Zr51 without introducing obvious microstructural changes, distinguishing the process from bulk welding.

关键词： electrical discharge, welding, nanoscale, metallic glass, metal

Interaction of Two Cavitation Bubbles in a Tube and its Effects on Heat Transfer

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Journal of Thermal Science 2017年第1期26卷 66-72页

作者： LIU Bin cai jun TAO Yuequn HUAI Xiulan Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China University of the Chinese Academy of Sciences Beijing 100080 China

When two cavitation bubbles exist in a confined space, the interaction between the bubbles significantly affects the characteristics of bubble dynamic behaviors. In this paper, a three-dimensional(3D) model is established to study the growth and collapse of two cavitation bubbles in a heated tube and its effects on heat transfer. The liquid and gas phases throughout the calculation domain are solved by a set of Navier-Stokes equations. It is assumed that the gas inside the bubble is compressible vapor, and the surrounding liquid is incompressible water. The mass transfer between two phases is ignored. The calculated bubble profiles were compared to the available experimental data, and a good agreement has been achieved. Then, the relationship among the bubble motion, flow field and pressure distributions was analyzed. On this basis, the effects of bubble interaction on the heat transfer between the wall surface and sounding liquid were discussed. It is found that heat transfer in the centre wall region is enhanced owing to the vortex flow and micro-jet induced by the bubble contraction and collapse. In contrast, the highest surface temperature appears in the surrounding region, which is mainly attributed to the thermal resistance induced by the bubble. The present study is helpful to understand the heat transfer phenomenon with cavitation in the liquid.

关键词： Cavitation, Interaction effects, Bubble dynamics, Heat transfer

Empirical Likelihood Method for Quantiles with Response Data Missing at Random

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Acta Mathematicae Applicatae Sinica 2012年第2期28卷 265-274页

作者： Xia-yan LI jun-qing YUAN Department of Statistics and Finance University of Science and Technology of China Hefei 230026 China School of Science Zhejiang University of Technology Hangzhou 310023 China

Empirical likelihood is a nonparametric method for constructing confidence intervals and tests, notably in enabling the shape of a confidence region determined by the sample data. This paper presents a new version of the empirical likelihood method for quantiles under kernel regression imputation to adapt missing response data. It eliminates the need to solve nonlinear equations, and it is essy to apply. We also consider exponential empirical likelihood as an alternative method. Numerical results are presented to compare our method with others.

关键词： confidence interval empirical likelihood quantile missing response regression imputation

Edge Engineering of MoS2 Nanoribbons as High Performance Electrode Material for Na-ion Battery： A First-Principle Study

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Chinese Journal of Chemistry 2017年第6期35卷 896-902页

作者： Jianbin Wang qing Zhao jun Chen Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) College of Chemistry Nankai University Tian/in 300071 China Collaborative Innovation Center of Chemical Science and Engineering Nankai University Tianjin 300071 China

Substantial effort has been made to search for electrode materials of Na-ion batteries with high energy/power density. The application of S-saturated zigzag MoS2 nanoribbons （MoSzNRs） for Na-ion batteries has been explored through density function theory （DFT）. The theoretical maximum specific capacity reaches 386.4 mAh,g t via dou- ble-side and special edge adsorption mode. The electronic structure reveals that there exists charge transfer between Na and MoS2NRs. The diffusion barrier on MoS2NRs （0.17 eV） is much lower than that of bulk MoS2 （1.15 eV）, indicating an excellent diffusion kinetics, in addition, the S-edge in MoS2NRs plays a key role. Firstly, the Mo edge was half saturated by S, which helps to stabilize the MoS2NRs as well as offer more intercalation sites for Na. On the other hand, Na migrates much faster on the S edge route in MoS2NRs. Our computational results show that S-saturated MoSzNRs exhibit a great potential as electrode materials for Na-ion batteries with high performance.

关键词： MoS2 nanoribbons Na-ion battery S-saturated edge effect density function theory

Low-thrust trajectory optimization in a full ephemeris model

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Acta Mechanica Sinica 2014年第5期30卷 615-627页

作者： Xing-Shan cai Yang Chen jun-Feng Li School of Aerospace Tsinghua University

The low-thrust trajectory optimization with complicated constraints must be considered in practical engineering. In most literature, this problem is simplified into a two-body model in which the spacecraft is subject to the gravitational force at the center of mass and the spacecraft＇s own electric propulsion only, and the gravity assist （GA） is modeled as an instantaneous velocity increment. This paper presents a method to solve the fuel-optimal problem of low-thrust trajectory with complicated constraints in a full ephemeris model, which is closer to practical engineering conditions. First, it introduces various perturbations, including a third body＇s gravity, the nonspherical perturbation and the solar radiation pressure in a dynamic equation. Second, it builds two types of equivalent inner constraints to describe the GA. At the same time, the present paper applies a series of techniques, such as a homotopic approach, to enhance the possibility of convergence of the global optimal solution.

关键词： Low-thrust Full ephemeris model Gravity assist

Biotransformation of nitro-polycyclic aromatic compounds by vegetable and fruit cell extracts

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2012年第4期13卷 248-253页

作者： Bo XIE jun YANG qing YANG School of Life Science and Biotechnology Dalian University of TechnologyDalian 116024China National Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Extracts from various vegetables and fruits were investigated for their abilities to reduce nitro-polycyclic aromatic hydrocarbons （NPAHs）. The extracts from grape and onion exhibited an interesting selectivity, yielding corresponding hydroxylamines or amines as major products under mild conditions of 30 ℃ and pH 7.0. Grape extracts reduced the 4-nitro-l,8-naphthalic anhydride with the highest conversion rate （〉99%） and the highest ratio of hydro- xylamine to amine （95：5）. In contrast, the onion extracts reduced 4-nitro-l,8-naphthalic anhydride with a conversion rate of 94% and a ratio of hydroxylamine to amine of 8：92. The thiol-reducing agent, 13-mercaptoethanol, and metal cations, Ca2＋ and Mg2＋, greatly increased the reductive efficiency. This work provides an alternative strategy for biotransformation of nitro-polycyclic compounds.

关键词： Biotransformation Nitro-polycyclic aromatic compounds Plant cell extracts Hydroxylamine Amine