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A general principle enabling the design of ultrastable metal nanocatalysts

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Science China Chemistry 2022年第4期65卷 641-642页

作者： xin Xu Collaborative Innovation Center of Chemistry for Energy Materials ShanghaiKey Laboratory of Molecular Catalysis and Innovative MaterialsMOE Key Laboratory of Computational Physical SciencesShanghai Key Laboratory of Bioactive Small MoleculesDepartment of ChemistryFudan UniversityShanghai 200433China

The design and the development of catalysts with high activity,high selectivity and high stability are of great significance for improving the efficiency of catalytic reactions,saving energy and reducing consumption,which is particularly important for achieving the dual-carbon *** development and the guidance of advanced catalytic theories are urgently needed[1].The Sabatier’s principle of catalyst activity states that the interaction between the reactants and the catalyst should not be too strong or too *** one of the basic theories of heterogeneous catalysis developed on this basis in the past century,it has profoundly affected the design of modern catalysts[2].

关键词： catalyst catalysis reactant

Ricci Curvature and Fundamental Group

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Chinese Annals of Mathematics,Series B 2006年第2期27卷 113-120页

作者： Yuanlong xin Dedicated to the memory of Shiing-Shen Chern

Abstract By refined volume estimates in terms of Ricci curvature, the two results due to J. Milnor （1968） are generalized.

关键词： Ricci curvature Fundamental group Volume growth

Paleoclimate data assimilation： Its motivation, progress and prospects

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Science China Earth Sciences 2016年第9期59卷 1817-1826页

作者： FANG Miao LI xin Cold and Arid Regions Environment and Engineering Research Chinese Academy of Sciences Lanzhou 730000 China University of Chinese Academy of Sciences Beijing 100049 China Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of Sciences Beijing 100101 China

Reconstructing past climate is beneficial for researchers to understand the mechanism of past climate change, recognize the context of modern climate change and predict scenarios of future climate change. Paleoclimate data assimilation(PDA), which was first introduced in 2000, is a promising approach and a significant issue in the context of past climate research. PDA has the same theoretical basis as the traditional data assimilation(DA) employed in the fields of atmosphere science, ocean science and land surface science. The main aim of PDA is to optimally estimate past climate states that are both consistent with the climate signal recorded in proxy and the dynamic understanding of the climate system through combining the physical laws and dynamic mechanisms of climate systems represented by climate models with climate signals recorded in proxies(e.g., tree rings, ice cores). After investigating the research status and latest advances of PDA abroad, in this paper, the background, concept and methodology of PAD are briefly introduced. Several special aspects and the development history of PAD are systematically summarized. The theoretical basis and typical cases associated with three frequently-used PAD methods(e.g., nudging, particle filter and ensemble square root filter) are analyzed and demonstrated. Finally, some underlying problems in current studies and key prospects in future research related to PDA are proposed to provide valuable thoughts on and a scientific basis for PDA research.

关键词： Climate reconstruction Paleoclimate modeling Proxies Data assimilation

BOTTLENECK" AND COUNTERMEASURE OF HIGH-TECHNOLOGIZATION OF MARINE INDUSTRY IN CHINA

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Chinese Geographical Science 2004年第1期14卷 15-20页

作者： LUANWei-xin SustainableDevelopmentalResearchCenterofMarineEconomy LiaoningNormalUniversityDalian116029P.R.China

This article deeply researched into the existent five problems and four main "bottlenecks" in the high-technologization of marine industry in China on the basis of analyzing the new trends in international marine problems and the necessity of implementing the strategy of developing China based on marine. This article brought up specific measures to the five "bottlenecks" according to the situations, and pointed out that new marine industry should be high-technologization and the traditional marine industry should be reformed by high-technique. The research results may provide the scientific basis for realizing the high-technologization of marine industry in China.

关键词： marine industry high-technologization bottleneck

Numerical simulation and scaling analysis of elasticity-induced lift force in a viscoelastic fluid between confining surfaces

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Journal of Hydrodynamics 2022年第4期34卷 756-766页

作者： xin Zhao Chao Wei The State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China Science and Technology on Vehicle Transmission Laboratory Beijing Institute of TechnologyBeijing 100081China

How to accurately characterize the lift force on the particles near the solid surfaces is an ongoing challenge in fluid mechanics and microfluidic techniques, especially in a complex system with viscoelastic fluid or/and soft surface that is commonly encountered in a biological system. The motions of the particles in vicinity of a surface can be simplified to be a rigid cylinder surrounded by the viscoelastic fluid moving along a substrate which can be rigid or soft according to different cases. In such an inertial free system with a wide range of Weissenberg number (Wi < 5.00, representing the ratio of the elastic force to the viscous force), firstly we numerically evaluate the influence of the systematic parameters, including the polymer viscosity, the geometry and Wi, on the net normal force for a cylinder closely moving along a rigid substrate, and the elasticity-induced lift force in a scaled form. It is shown that a strong shear arises in the viscoelastic confinement between the moving cylinder and the rigid substrate, it leads to the asymmetry of the first normal stress distribution around the cylinder, and thus the lift force. Then, the influence of a soft substrate on the lift force is considered, and we find that the lift force induced by the viscoelastic fluid always dominates in magnitude over that induced by the soft substrate deformation. This work provides a reliable scaling that can be utilized to quantify the elasticity-induced lift force on the particles in a viscoelastic system, such as the micro- and nanofluidic systems in biological applications.

关键词： Viscoelastic fluid scaling expression computational fluid dynamics lift force

Robust Latent Factor Analysis for Precise Representation of High-Dimensional and Sparse Data

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IEEE/CAA Journal of Automatica Sinica 2021年第4期8卷 796-805页

作者： Di Wu xin Luo the Chongqing Key Laboratory of Big Data and Intelligent Computing Chongqing Institute of Green and Intelligent TechnologyChinese Academy of SciencesChongqing 400714 the Chongqing School University of Chinese Academy of SciencesChongqing 400714China

High-dimensional and sparse(HiDS)matrices commonly arise in various industrial applications,e.g.,recommender systems(RSs),social networks,and wireless sensor *** they contain rich information,how to accurately represent them is of great significance.A latent factor(LF)model is one of the most popular and successful ways to address this *** LF models mostly adopt L2-norm-oriented Loss to represent an HiDS matrix,i.e.,they sum the errors between observed data and predicted ones with *** L2-norm is sensitive to outlier ***,outlier data usually exist in such *** example,an HiDS matrix from RSs commonly contains many outlier ratings due to some heedless/malicious *** address this issue,this work proposes a smooth L1-norm-oriented latent factor(SL-LF)*** main idea is to adopt smooth L1-norm rather than L2-norm to form its Loss,making it have both strong robustness and high accuracy in predicting the missing data of an HiDS *** results on eight HiDS matrices generated by industrial applications verify that the proposed SL-LF model not only is robust to the outlier data but also has significantly higher prediction accuracy than state-of-the-art models when they are used to predict the missing data of HiDS matrices.

关键词： High-dimensional and sparse matrix L1-norm L2 norm latent factor model recommender system smooth L1-norm

Roadmap towards new generation liquid metal thermal interface materials

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Science China(Technological Sciences) 2023年第6期66卷 1530-1550页

作者： ZHANG xin DENG ZhongShan CAS Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China

As electronic devices continue to evolve toward miniaturization and integration,traditional thermal interface materials(TIMs)are no longer able to meet the ever-tougher thermal management *** to their high thermal conductivity and excellent conformability within a highly confined space,liquid metals have great potential for advanced thermal management in various cutting-edge devices and have become a key candidate for next-generation high-performance *** addition to already known materials,such as liquid metal alloy TIMs,particle-filled liquid metal TIMs,and liquid metal-filled TIMs,more TIMs are still being *** review presents a systematic classification of the liquid metal TIMs developed thus far,interprets the fundamental mechanisms underlying material innovation and in-situ heat transfer enhancement,and comparatively evaluates their respective advantages and ***,a series of representative theoretical models for characterizing the thermal conductivities of composites are summarized,and the limits of the thermal conductivity of liquid metal TIMs are predicted to guide practical R&D *** address the urgent need for higher-performance TIMs to overcome future thermal management challenges of electronic devices,a roadmap is outlined for the development of high-performance liquid metal TIMs,and a strategy for running these technologies is demonstrated.

关键词： liquid metal thermal interface material thermal conductivity thermal conductivity model thermal contact resistance

Progress in achieving high-performance piezoresistive and capacitiveflexible pressure sensors: A review

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Journal of Materials Science & Technology 2020年第8期36卷 175-188页

作者： Wufan Chen xin Yan College of Information Science and Engineering State Key Laboratory of Synthetical Automation for Process IndustriesNortheastern UniversityShenyang110819China

Electronic skin(e-skin) and flexible wearable devices are currently being developed with broad application prospects. Transforming electronic skin(e-skin) into true ¨skin¨is the ultimate goal. Tactile sensing is a fundamental function of skin and the development of high-performance flexible pressure sensors is necessary to realize thus. Many reports on flexible pressure sensors have been published in recent years,including numerous studies on improving sensor performance, and in particular, sensitivity. In addition,a number of studies have investigated self-healing materials, multifunctional sensing, and so on. Here,we review recent developments in flexible pressure sensors. First, working principles of flexible pressure sensors, including piezoresistivity, capacitance, and piezoelectricity, are introduced, as well as working mechanisms such as triboelectricity. Then studies on improving the performance of piezoresistive and capacitive flexible pressure sensors are discussed, in addition to other important aspects of this intriguing research field. Finally, we summarize future challenges in developing novel flexible pressure sensors.

关键词： Electronic skin Flexible pressure sensor Piezoresistivity Capacitive pressure sensor

Interactive Design of Cubic IPH Spline Curves

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Journal of Systems Science & Complexity 2023年第3期36卷 1302-1318页

作者： ZHANG Jingjing LI xin School of Mathematical Sciences Anhui UniversityHefei 230026China University of Science and Technology of China Hefei 230026China

Indirect Pythagorean hodographs(IPH)spline curves are a set of curves which have rational Pythagorean hodographs after reparameterization by a fractional quadratic *** this paper,the authors provide an algorithm to interactively design a cubic IPH spline curve from any given control *** method has the same friendly interface and properties as those for B-splines,meanwhile facilitates intuitive and efficient construction of open and closed IPH spline *** key idea is to solve the ratios of a set of auxiliary points associated with the edges and then construct a piecewise cubic IPH spline curve which has as high as possible continuity,i.e.,the absolute curvature value of the adjacent curve segments are the same.A very interesting observation is that for any open control polygon,a quadratic B-spline curve can have continuous absolute curvature by carefully choosing the knots as the function of the control points.

关键词： Bezier curve offsets pythagorean hodograph rational parameterization