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Real-time in-situ monitoring of chiral changes during a reaction at single-molecule level

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Science China Chemistry 2024年第2期67卷 422-423页

作者： Min tan Dong xiang Institute of Modern Optics and Center of Single-Molecule Science Tianjin Key Laboratory of Micro-scale Optical Information Science and TechnologyNankai UniversityTianjin300350China School of Materials Science and Engineering Smart Sensing Interdisciplinary Science CenterNankai UniversityTianjin300350China TongLu FeiRan Garment–Nankai University Joint Laboratory Nankai UniversityTianjin300350China

Molecular chirality is a widespread phenomenon in nature,playing a critical role in various fields such as chemistry [1],life sciences [2], and materials science [3], and has therefore attracted significant attention and research by scholars [4–6].However, the chirality in chemical reactions is often dynamic, making real-time monitoring of chiral changes during chemical reactions at the single-molecule level extremely challenging.

关键词： chiral chirality critical

Electrical characteristics of a fractional-order 3×n Fan network

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Communications in Theoretical physics 2024年第4期76卷 176-187页

作者： Zhi-Zhong tan xin Wang Department of physics Nantong UniversityNantong 226019China

In this article a new achievement of fractional-order 3×n Fan networks is *** the first step,the RT-I method is used to derive the general formulae of the equivalent impedance of fractional-order 3×n Fan *** the second part,the effects of five system parameters(L,C,n,α and β)on amplitude-frequency and phase-frequency characteristics are *** the same time,the amplitude-frequency and phase-frequency characteristics of the fractional order 3×n Fan network are revealed by Matlab *** work has important theoretical and practical significance for resistor network models in the field of natural science and engineering technology.

关键词： fractional-order circuit amplitude-frequency characteristics phase-frequency characteristics RT-V theory

Numerical analysis of a projecting wall type oscillating water column(pW-OWC)wave energy converter in regular waves

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Journal of Hydrodynamics 2024年第3期36卷 479-491页

作者： Lei tan Ruiyuan Chang Tomoki Ikoma Department of Oceanic Architecture and Engineering College of Science and TechnologyNihon UniversityChibaJapan

Oscillating water column(OWC)based wave energy absorption devices are classic which have been widely used for harnessing ocean wave *** paper presents a numerical study on a projecting wall(pW)type OWC wave energy converter in regular *** computational fluid dynamics(CFD)modelling of a stationary floating pW-OWC model in a three-dimensional wave flume is achieved by the software *** analyses are carried out based on CFD simulations and the linear potential flow solutions with modifications to account for turbine-induced *** present numerical solutions are validated against our previous experimental *** is found that both the CFD and modified linear potential flow predictions are in reasonably good agreements with the experimental data in the first order results of OWC and air pressure *** the nonlinear responses are included in the result,the modified linear potential flow solution is found to slightly under-estimate the wave energy conversion performance at long *** the airflows above and below the chamber orifice,the CFD results suggest that they are almost unidirectional,oscillating in not only the base frequency but also subharmonic and ultraharmonic *** evolution of the OWC responses during an entire period and the phase analysis based on CFD simulations are *** phase results provide the crucial evidence to the reasonability of the physics-based modification of the potential flow model in modelling of *** present results and analysis are expected to be beneficial to the understanding on the physical mechanism of OWCs and the design of phase control strategies.

关键词： Computational fluid dynamics(CFD)simulation hydrodynamic analysis oscillating water column(OWC)damping orifice airflow phase difference

Learnware:small models do big

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Science China(Information Sciences) 2024年第1期67卷 39-50页

作者： Zhi-Hua ZHOU Zhi-Hao tan National Key Laboratory for Novel Software Technology Nanjing University

There are complaints about current machine learning techniques such as the requirement of a huge amount of training data and proficient training skills,the difficulty of continual learning,the risk of catastrophic forgetting,and the leaking of data privacy/*** research efforts have been focusing on one of those concerned issues separately,paying less attention to the fact that most issues are entangled in *** prevailing big model paradigm,which has achieved impressive results in natural language processing and computer vision applications,has not yet addressed those issues,whereas becoming a serious source of carbon *** article offers an overview of the learnware paradigm,which attempts to enable users not to need to build machine learning models from scratch,with the hope of reusing small models to do things even beyond their original purposes,where the key ingredient is the specification which enables a trained model to be adequately identified to reuse according to the requirement of future users who know nothing about the model in advance.

关键词： artificial intelligence machine learning learnware

Estimation of tunnel axial orientation in the interlayered rock mass using a comprehensive algorithm

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2579-2590页

作者： Hui Li Weizhong Chen xianjun tan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The axial selection of tunnels constructed in the interlayered soft-hard rock mass affects the stability and safety during *** optimization is primarily based on experience or comparison and selection of alternative values under specific geological *** this work,an intelligent optimization framework has been proposed by combining numerical analysis,machine learning(ML)and optimization *** automatic and intelligent numerical analysis process was proposed and coded to reduce redundant manual *** conventional optimization algorithm was developed from two aspects and applied to the hyperparameters estimation of the support vector machine(SVM)model and the axial orientation optimization of the ***,the comprehensive framework was applied to a numerical case study,and the results were compared with those of other *** results of this study indicate that the determination coefficients between the predicted and the numerical stability evaluation indices(STIs)on the training and testing datasets are 0.998 and 0.997,*** a given geological condition,the STI that changes with the axial orientation shows the trend of first decreasing and then increasing,and the optimal tunnel axial orientation is estimated to be 87.This method provides an alternative and quick approach to the overall design of the tunnels.

关键词： Tunnel Building information modeling Design optimization particle swarm optimization Support vector machine(SVM)

Higher-order expansions of powered extremes of logarithmic general error distribution

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 47-54页

作者： tan xiao-feng LI Li-hui School of Mathematics and Statistics Southwest UniversityChongqing 400715China

In this paper,Let M_(n)denote the maximum of logarithmic general error distribution with parameter v≥***-order expansions for distributions of powered extremes M_(n)^(p)are derived under an optimal choice of normalizing *** is shown that M_(n)^(p),when v=1,converges to the Frechet extreme value distribution at the rate of 1/n,and if v>1 then M_(n)^(p)converges to the Gumbel extreme value distribution at the rate of(loglogn)^(2)=(log n)^(1-1/v).

关键词： logarithmic general error distribution convergence rate higher-order expansion powered ex-treme

Electrochemical radical-polar crossover:a radical approach to polar chemistry

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Science China Chemistry 2024年第2期67卷 450-470页

作者： Zhoumei tan Haonan Zhang Kun xu Chengchu Zeng Faculty of Environment and Life Beijing University of TechnologyBeijing100124China

Radical-polar crossover(RpC) reaction bridges the gap between one-and two-electron reactivities,thus providing an ideal solution to overcome the limitations of both radical and polar *** this manifold,organic electrochemistry provides a uniquely facile strategy to access a diverse array of radical intermediates,thus broadening the chemical space of the RpC *** review highlights the synthetic advances in the field of electrochemical RpC reactions since 2020,with an emphasis on the substrate scope,reaction limitation and mechanistic *** related RpC reactions are categorized as netoxidative,net-reductive,or redox neutral transformations.

关键词： electrosynthesis radical-polar crossover radical chemistry polar chemistry alkene functionalization

THE STABILITY OF BOUSSINESQ EQUATIONS WITH pARTIAL DISSIpATION AROUND THE HYDROSTATIC BALANCE

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Acta Mathematica Scientia 2024年第4期44卷 1466-1486页

作者： Saiguo xU Zhong tan School of Mathematics and Statistics Wuhan UniversityWuhan 430072China School of Mathematical Sciences Xiamen UniversityXiamen 361005China Shenzhen Research Institute of xiamen University Shenzhen 518057China

This paper is devoted to understanding the stability of perturbations around the hydrostatic equilibrium of the Boussinesq system in order to gain insight into certain atmospheric and oceanographic *** Boussinesq system focused on here is anisotropic,and involves only horizontal dissipation and thermal *** the 2D case R^(2),due to the lack of vertical dissipation,the stability and large-time behavior problems have remained open in a Sobolev *** the spatial domain T×R,this paper solves the stability problem and gives the precise large-time behavior of the *** decomposing the velocity u and temperatureθinto the horizontal average(ū,θ)and the corresponding oscillation(ū,θ),we can derive the global stability in H~2 and the exponential decay of(ū,θ)to zero in H^(1).Moreover,we also obtain that(ū_(2),θ)decays exponentially to zero in H^(1),and thatū_(1)decays exponentially toū_(1)(∞)in H^(1)as well;this reflects a strongly stratified phenomenon of buoyancy-driven *** addition,we establish the global stability in H^(3)for the 3D case R^(3).

关键词： Boussinesq equations partial dissipation stability decay

Influence of ground effect on flow field structure and aerodynamic noise of high-speed trains

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Journal of Zhejiang University-Science A(Applied physics & Engineering) 2024年第2期25卷 147-160页

作者： xiaoming tan Linli GONG xiaohong ZHANG Zhigang YANG Key Laboratory of Intelligent Manufacturing and Service performance Optimization of Laser and Grinding in Mechanical Industry Hunan Institute of Science and TechnologyYueyang414000China Key Laboratory of Traffic Safety on Track(Central South University) Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangsha410075China

The simulation of the ground effect has always been a technical difficulty in wind tunnel tests of high-speed *** this paper,large eddy simulation and the curl acoustic integral equation were used to simulate the flow-acoustic field results of high-speed trains under four ground simulation systems(GSSs):“moving ground+rotating wheel”,“stationary ground+rotating wheel”,“moving ground+stationary wheel”,and“stationary ground+stationary wheel”.By comparing the fluid-acoustic field results of the four GSSs,the influence laws of different GSSs on the flow field structure,aero-acoustic source,and far-field radiation noise characteristics were investigated,providing guidance for the acoustic wind tunnel testing of high-speed *** calculation results of the aerodynamic noise of a 350 km/h high-speed train show that the moving ground and rotating wheel affect mainly the aero-acoustic performance under the train *** influence of the rotating wheel on the equivalent sound source power of the whole vehicle was not more than 5%,but that of the moving ground slip was more than 15%.The average influence of the rotating wheel on the sound pressure level radiated by the whole vehicle was 0.3 dBA,while that of the moving ground was 1.8 dBA.

关键词： High-speed train Aero-acoustics Flow field structure Large eddy simulation Moving ground condition Rotating wheel