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基于分子束外延技术可控制备Bi原子团簇的研究

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原子与分子物理学报 2025年第2期42卷 79-84页

本研究基于分子束外延(MBE)技术在Si(111)衬底表面成功制备金属Bi原子团簇.首先,分别在100℃、125℃、150℃、175℃、200℃的生长温度下,制备了大小均一、密度不同的Bi原子团簇.实验结果表明,可以通过改变生长温度来精细控制Bi原子团簇... 详细信息

本研究基于分子束外延(MBE)技术在Si(111)衬底表面成功制备金属Bi原子团簇.首先,分别在100℃、125℃、150℃、175℃、200℃的生长温度下,制备了大小均一、密度不同的Bi原子团簇.实验结果表明,可以通过改变生长温度来精细控制Bi原子团簇的密度,当温度升高100℃,密度从1.05×10^(11)cm^(-2)降低至2.5×10^(7)cm^(-2),实现对团簇密度4个数量级的可控调节,并且发现Bi原子团簇密度对生长温度的依赖性符合经典成核理论.其次,分别在10 s、15 s、20 s的沉积时长下,制备了密度相同、尺寸各异的Bi原子团簇.实验结果表明,可以通过改变沉积时长来精细控制Bi原子团簇的尺寸:当沉积时长增加10 s,高度和直径分别从8.5 nm和65 nm增大到13.7 nm和100 nm,实现对团簇尺寸在10 nm高度、80 nm直径范围的可控调节,并且发现Bi原子团簇尺寸对沉积时长的依赖性符合晶体生长动力学.与分子束外延制备传统的Ⅲ族(Al,Ga,In)原子团簇做对比,这些结果可以为制备Ⅴ族原子团簇提供实验参考和指导,从而促进纳米级含Bi材料的制备.

关键词：分子束外延 Bi原子团簇生长温度沉积时长经典成核理论晶体生长动力学

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Duals of Hardy Spaces of B-valued Martingales for 0

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Acta Mathematica Sinica,English Series 2014年第8期30卷 1365-1380页

作者： lin yu School of Science China Three Gorges University

The dual of B-valued martingale Hardy space Hr^s（p）（B） with small index 0 〈 r ≤ 1, which is associated with the conditional p-variation of B-valued martingale, is characterized. In order to obtain the results, a new type of Campanato spaces for B-valued martingales is introduced and the classical technique of atomic decompositions is improved. Some results obtained here are connected closely with the p-uniform smoothness and q-uniform convexity of the underlying Banach space.

关键词： Dual spaces B-valued martingale Hardy spaces

The Enhanced Period Map and Equivariant Deformation Quantizations of Nilpotent Orbits

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Acta Mathematica Sinica,English Series 2024年第3期40卷 885-934页

作者： Shi lin yu Department of Mathematics School of Mathematical SciencesXiamen UniversityXiamen 361005P.R.China

In a previous paper,the author and his collaborator studied the problem of lifting Hamil-tonian group actions on symplectic varieties and Lagrangian subvarieties to their graded deformation quantizations and apply the general results to coadjoint orbit method for semisimple Lie *** even quantizations were considered *** this paper,these results are generalized to the case of general quantizations with arbitrary *** key step is to introduce an enhanced version of the(truncated)period map defined by Bezrukavnikov and Kaledin for quantizations of any smooth sym-plectic variety X,with values in the space of Picard Lie algebroid over *** an application,we study quantizations of nilpotent orbits of real semisimple groups satisfying certain codimension condition.

关键词： Coadjoint orbit method deformation quantization Harish-Chandra modules semisimple Liegroups

Influence of coupled characteristics on the internally-staged combustor under low-power operation

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航空动力学报 2017年第1期32卷 42-52页

作者： KANG Yao lin yu-zhen Hunan Aviation Powerplant Research Institute Aero Engine(Group)Corporation of China National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics School of Energy and Power EngineeringBeijing University of Aeronautics and Astronautics

An ultra-low emissions combustor,namely low emission stirred swirl(LESS)combustor was studied,based on a scheme of internally-staged/lean premixed and prevaporized(LPP)*** LESS combustor consists of central pilot stage and outer surrounded coaxially main stage,between which there exists aphysical isolation,namely the step *** existence of step height delayed the pilot and main jets *** and numerical studies were carried out to investigate the influence of the step height on the combustion performance.A single dome rectangular combustor was utilized to conduct the lean lightoff and blowout experiments,and pollutant emission *** experimental results showed that with the increase of step height by 38%,the lean lightoff and blowout fuel air ratio decreased by 57.4% and 37.5%,the NOx emission increased by 35.1%,and the combustion efficiency increased by 1.78%;while the CO,unburned hydrocarbons(UHC)emissions ***,the total pressure loss was kept nearly ***-reacting and reacting flow fields were numerically investigated to analyze the coupled characteristics of pilot and main jets with different step heights.A comparison of flow characteristics,spray structure,and combustion component as well as temperature field with different step heights was *** numerical results showed that the increase of the step height shifted the peak velocity *** enlargement of the primary recirculation zone(PRZ)resulted in the increase of the combustion efficiency and NOx emission,while the CO,UHC emissions decreeased.

关键词：航空动力编辑研究工作

Gradient estimates and coupling property for semilinear SDEs driven by jump processes

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Science China Mathematics 2015年第2期58卷 447-458页

作者： SONG yu lin School of Mathematical Sciences Beijing Normal University

Let L be a L′evy process with characteristic measureν,which has an absolutely continuous lower bound *** Lebesgue measure on *** using Malliavin calculus for jump processes,we investigate Bismut formula,gradient est... 详细信息

关键词： jump processes Bismut formula gradient estimates coupling property

Optimality conditions in set optimization employing higher-order radial derivatives

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Applied Mathematics(A Journal of Chinese Universities) 2017年第2期32卷 225-236页

作者： yu Guo-lin Department of Mathematics Beifang University of NationalitiesYinchuan 750021China.

There are two approaches of defining the solutions of a set-valued optimization problem： vector criterion and set criterion. This note is devoted to higher-order optimality conditions using both criteria of solutions for a constrained set-valued optimization problem in terms of higher-order radial derivatives. In the case of vector criterion, some optimality conditions are derived for isolated （weak） minimizers. With set criterion, necessary and sufficient optimality conditions are established for minimal solutions relative to lower set-order relation.

关键词： higher-order radial derivative optimality conditions set-valued optimization vector criterion,set criterion.

Firm-level Strategic Competition and Peer Effects in Corporate Investment among Chinese Firms

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Journal of Systems Science and Systems Engineering 2022年第6期31卷 753-774页

作者： Jianing Li yu-En lin School of Business Administration Northeastern UniversityShenyangLiaoning110000China Center for Quantitative Economics Jilin UniversityChangchunjilin130015China

This study investigates the influence of strategic competition on peer effects in corporate investment by using a sample of 28,522 observations of Chinese listed companies from 2008 to *** study develops a linear-in means model and uses an instrumental variables approach,and uses the competitive strategy measure(CSM)and Lerner index as proxies of competitive strategies and competitive positions to capture the firm-level *** empirical results demonstrate that when firms compete as strategic substitutes and when firms are in higher competitive positions,the peer effects in corporate investment are significant and *** addition,in circumstances of high information asymmetry,firms competing as strategic substitutes and firms in high competitive positions rely more on information related to investment from peer ***,industry policies and barriers do not significantly influence peer effects in *** study offers new empirical evidence regarding peer effects in corporate investment in China.

关键词： Corporate investment peer effects competitive strategy competitive position

Microstructure and mechanical properties of a hot-extruded Al-based composite reinforced with core–shell-structured Ti/Al3Ti

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International Journal of Minerals,Metallurgy and Materials 2017年第12期24卷 1431-1437页

作者： Li Zhang Bao-lin Wu yu-lin Liu School of Materials Science and Engineering Shenyang Aerospace UniversityShenyang 110136China Liaoning Key Laboratory of Aviation Light Alloy and Processing Technology Shenyang Aerospace UniversityShenyang 110136China

An Al-based composite reinforced with core–shell-structured Ti/Al_3Ti was fabricated through a powder metallurgy route followed by hot extrusion and was found to exhibit promising mechanical properties. The ultimate tensile strength and elongation of the composite sintered at 620°C for 5 h and extruded at a mass ratio of 12.75:1 reached 304 MPa and 14%, respectively, and its compressive deformation reached 60%. The promising mechanical properties are due to the core–shell-structured reinforcement, which is mainly composed of Al_3Ti and Ti and is bonded strongly with the Al matrix, and to the reduced crack sensitivity of Al_3Ti. The refined grains after hot extrusion also contribute to the mechanical properties of this composite. The mechanical properties might be further improved through regulating the relative thickness of Al–Ti intermetallics and Ti metal layers by adjusting the sintering time and the subsequent extrusion process.

关键词： microstructure aluminum-based composites Ti/Al3Ti reinforcements mechanical properties

NUMERICAL SI MULATION OF MOVING SCOUR BOUNDARY AND TURBULENCE FLOWAROUND SUBMARINE PIPElinES

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Journal of Hydrodynamics 2005年第4期17卷 404-411页

作者： LI yu-cheng LU lin State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

A two dimensional vertical mathematical model is proposed in this paper for simulating the equilibrium profile of local scour around submarine pipelines. The current model is composed of a new k-ε turbulence model, fitting moving boundary with pre-meshed grid lines and incipient criterion of shear stress for sediments. Employing the proposed model, an instance is carried out numerically and compared with experiments. The calculation results agree well with the experiments. It shows that the improved two equation turbulence model, adopted in this paper is appropriate to simulating the turbulent flow ficld around submarine pipelines, fitting moving boundary with pre-mcshed grid lines method is efficient for moving boundary problems in a multiply connected domain and the stability evaluation method for seabed with critical shear stress based on log-wall law is a reliable choice.

关键词： numerical simulation submarine pipeline local scour moving boundary turbulence model