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Enantio-divergent C–h borylation with two different ligands from a single chiral source

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Science China Chemistry 2025年第1期68卷 226-232页

作者： Rongrong du Senmiao Xu State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences College of Material Chemistry and Chemical Engineering Key Laboratory of Organosilicon Chemistry and Material TechnologyMinistry of Education Hangzhou Normal University University of Chinese Academy of Sciences

Reported here is an iridium-catalyzed enantio-divergent C（sp3）–h borylation of α-gem-dimethyl groups of trifluoromethyl ketone-derived hydrazones to construct a series of acyclic all-carbon quaternary stereocenters with a high level of chiral induction. Two different chiral bidentate boryl ligands from a common chiral source not only can switch the enantioselectivity but also are complementary in terms of the substrate scope.

关键词： asymmetric catalysis C–h borylation all-carbon quaternary stereocenters synthetic methods

Microstructural Dependence of Damping Behaviour of Eutectoid Zn-Al Based Alloy (ZA27)──Discussion of "Damping Behaviour and Mechanism of Graphite Particulate Reinforced Metal Matrix Composites

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Journal of Materials Science & Technology 1999年第2期15卷 178-180页

作者： Zhu, y.h. Institute de Investigaciones en Materiales UNAM Mexico D.F. 04510 Apart.P.70-360 Mexico Dept. of Manufacturing Engineering Hong Kong Polytechnic University Hong Kong

Constructing 2D bismuth-based heterostructure for highly efficient photocatalytic CO2 reduction

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Tungsten 2025年第1期7卷 71-79页

作者： Ruo-hang Xu hao-yu Jiang Dan-Dan Cui Kun-Rong du hong-Run Zhang Sheng-Jie Xu ya-Qi Li Zhi-Zhen Ren Liang Wang Wei-Chang hao yi du School of Physics and BUAA-UOW Joint Research Centre Beihang University Shenzhen Institute of Beihang University Centre for Catalysis and Clean Energy School of Environment and Science Griffith University

Reforming carbon dioxide（CO2） into fuels and valuable chemicals using solar energy.h.lds significant potential for emission reduction and addressing energy supply *** recombination of photocarriers remains a major obstacle,however,to enhancing solar energy conversion efficiency in the photocatalytic reaction *** two-dimensional materials,constructing heterogeneous structures has emerged as an effective strategy to enhance the separation of photoexcited carriers by leveraging the internal electric field at the heterogeneous ***,we present a facile strategy for preparing Bi4NbO8Br/Bi2WO6plate-on-plate Z-scheme junctions with a strong internal electric field by in situ *** unique heterostructure facilitates efficient separation and transport of photoexcited charges by.h.rnessing the internal electric field induced by chemical bonding at the lateral ***,the Bi4NbO8Br/Bi2WO6heterostructure exhibits enhanced CO2photoreduction properties,along with a CO yield rate of approximately 35 μmol·g-1·h-1under full light *** work offers novel insights into the synthesis of unique hetero structures intended to enhance the efficiency of photocatalytic CO2reduction.

关键词： Bi4NbO8Br/Bi2WO6 CO2 reduction heterostructures Photocatalysts

MEChANICAL BEhAVIOR OF FCC CRySTAL SIMULATED By 3-D DISCRETE DISLOCATION DyNAMICS

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Acta Metallurgica Sinica(English Letters) 2008年第2期21卷 94-102页

作者： y.yu X.X. Pan y.h. Rong School of Materials Science and Engineering Shanghai Jiaotong University Shanghai 200030 China Institute of Structural Mechanics China Academy of Engineering Physics Mianyang 621900 ChinaManuscript received 31 May 2007

To simulate the mechanical behavior of the FCC crystal with the lower Peierls stress, the stiff property and physical meaning of the differential equation group consisting of dislocation evolution and mechanical state was investigated based on the 3-D discrete dislocation dynamics; the results indicate that the differential equation group is serious stiff, namely the external stress changes more quickly than dislocation evolution. Using the established numerical algorithm, the mechanical behavior of FCC crystal was simulated with the dislocations located in the parallel slip planes, and the effect of strain rate on the dislocation configuration and mechanical behavior, and the sat- uration process of mobile dislocation were discussed. The simulation results indicate that the numerical algorithm can efficiently simulate the dislocation dipole and the low strain rate loading.

关键词： FCC crystal Mechanical behavior Dislocation dynamics Nu-merical simulation

ON ThE DyNAMIC ChARACTERISTICS OF MOULD-FILLING UNDER COUNTERGRAVITy

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Acta Metallurgica Sinica(English Letters) 1997年第5期10卷 409-414页

作者： Zeng, J.M. Gu, h. Zhou, y.h. Guangxi Univ Nanning China

In this paper, the mathematical models for mould-filling under countergravity are derived on the basis of the principle of momentum. Dynamic processes of mould-filling are observed on a perspex model by means of high speed photography. The results indicate that the mould-filling under countergravity can be described by the second order nonlinear differential equations characterized by damping oscillations. The velocity oscillations amplify as the pressuring speed increases if the pressure differential functions are of the same type. On the other hand, if the functions are of different type, then the velocity oscillations depend upon whether the functions progressively increase or decrease. Velocity oscillations can be diminished dramatically by increasing the local damping within the gating system.

关键词： casting mould-filling dynamics

2nd UMN-CAS Bilateral Seminar on PM2.5 science, health effects and control technologies, October 7-8, 2015 at 3M Innovation Center, Maplewood, MN, USA

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Particuology 2016年第4期14卷 141-142页

作者： David y.h. Pui Junji Cao University of Minnesota MN 55455 USA Institute of Earth Environment Chinese Academy of Sciences Xi'an China

The First UMN-CAS Bilateral Seminar was successfully.h.ld in Xi＇an, China, May 27-28,2014. A summary of the 1 st Bilateral Seminar was published in Particuology 16 （2014）, 227-229. The Second UMN-CAS Bilateral Semi... 详细信息

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COORELATION ANALySIS OF SURFACE PRESSURE FLUCTUATIONS ON ThREE EQUISPACED CyLINDERS

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Journal of hydrodynamics 2001年第2期13卷 55-62页

作者： Dong, L.y. Xu, y.h. huang, D.Q. Inst. of Appl. Math. and Mech. Shanghai Univ. Shanghai 200072 China

The fluctuating pressures on the surface of three circular cylinders in equispaced arrangement were measured simultaneously in the medium subcritical regime (Re=3×104). The distributions of their rms values and circumferential correlation were obtained in the spacing range from 1.25 to 6.0. The spatial correlation of pressures of two pressure taps on two different cylinders at the same azimuth was investigated as well. Owing to different flow patterns in various arrangements and spacing, these correlation curves of pressure show different distributions. The lift fluctuation can be estimated qualitatively from the circumferential coefficient curve with the knowledge of the rms pressure distribution. Some critical spacing for each arrangement were found that the flow regimes and the corresponding pressure correlation take a sudden change. Flow interference between cylinders in each arrangement was also discussed with various flow regimes.

关键词： Cylinders (shapes) Experiments Flow interactions Flow patterns Pressure distribution Pressure measurement

EVOLUTION OF MICROSTRUCTURE OF Sn-Ag-Cu LEAD-FREE FLIP ChIP SOLDER JOINTS duRING AGING PROCESS

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Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 301-306页

作者： y.h. Tian C.Q. Wang W.F. Zhou State Key Lab of Advanced Welding Production and Technology Harbin Institute of Technology Harbin 150001 China

Flip chip bonding has become a primary technology that has found application in the chip interconnection process in the electronic manufacturing industry in recent years. The solder joints of the flip chip bonding are small and consist of complicated microstructures such as Sn solution, eutectic mixture, and intermetallic compounds （IMCs）, whose mechanical performance is quite different from the original solder bulk. The evolution of microstructure of the flip chip solder joints under thermal aging was analyzed. The results show that with an increase in aging time, coarsening of solder bulk matrix and AuSn4 IMCs occurred within the solder. The IMCs that are formed at the bottom side of the flip chip bond were different from those on the top side during the aging process. （Cu, Ni, Au）0Sn5 were formed at the interfaces of both sides, and large complicated （Au,Ni, Cu）Sn4 IMCs appeared for some time near the bottom interface after aging, but they disappeared again and thus （Cu,Ni, Au ）0Sn5 IMC thickness increased considerably. The influence of reflow times during the flip chip bonding （as-bonded condition） on the characteristics of interfacial IMCs was weakened when subjected to the aging process.

关键词： lead free solder flip chip aging

Deciphering the role of ultra-low-loaded rhodium in NiFe-MIL-53 for superior oxygen evolution reaction

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Journal of Energy Chemistry 2025年第1期100卷 77-86页

作者： Jinzhi Jia Jinhua Zhang Kailu Guo Lanyue Zhang Gening du hao you Junfeng huang Mudong Tu hua Li yong Peng Wei Dou Cailing Xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering School of Materials and Energy Lanzhou University College of Chemistry and Chemical Engineering Luoyang Normal University

Designing highly active and stable electrocatalysts of oxygen evolution reaction （OER） is one of the crucial *** this study,a novel OER electrocatalyst,NiFe-MIL-53 modified with ultra-low rhodium（Rh@NiFe-MIL-53）,is successfully prepared via the hydrothermal ***-situ Raman spectroscopy and electrochemical impedance spectroscopy reveal that the doped Rh accelerates the phase transformation of NiFe-MIL-53 and the in-situ formed Rh@NiFeOOh is the actual active *** importantly,the enhanced reversibility of electrochemical reconstruction between NiFeOOh and NiFe（Oh）2after doping Rh is beneficial for improving the electrochemical stability of the catalyst.X-ray photoelectron spectroscopy spectra show the strong electronic interaction between single-atom Rh and Ni/Fe in Rh@***,theoretical calculations confirm that the integration of single-atom Rh into the NiFeOOh successfully reduces the band gap,regulates the d-band center （εd）,accelerates the charge transfer,and optimizes the adsorption behavior of oxygen-containing intermediates,thereby lowering the energy barrier of rate-determining ***,the optimized Rh@NiFe-MIL-53 exhibits excellent OER activity （240 mV） with a small Tafel slope of 48.2 mV dec-1and long-term durability (over1270 h at 10 m A cm-2and 110 h at 200 mA cm-2).This work presents a new perspective on designing highly efficient OER electrocatalysts.

关键词： X ray photoelectron spectroscopy