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Journal of Hydrodynamics 2012年第3期24卷 332-338页

作者： LI Wei LI xiao-ping LI shun-chu LI Quan-yong State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500 China Institute of Applied Mathematics Xihua University Chengdu 610039 China

When the classical nonlinear partial differential equations are used to model the fractal reservoir, based on the assumption of low compressibility fluids, the effects of the quadratic gradient term are ignored, which would be questionable for mixed gas reservoirs and low permeability reservoirs. To consider the influence of the wellbore storage, the nonlinear mathematical flow model of the fractal multilayer reservoir is built in this paper, with three kinds of outer boundaries （infinite boundaries, constant pressure boundaries and closed boundaries）. Using the Laplace transform method, the solutions for the dimensionless reservoir pressure and the bottom hole pressure in the Laplace space are obtained. An analysis shows that the solutions involve similar structures even for three different kinds of outer boundaries, and can be unified as a continuous fraction. The unified expression would make it more convenient to analyze the formation parameters, which greatly facilitates the development of the well test analysis software.

关键词： fractal multilayer reservoir quadratic gradient wellbore storage similar structure

Effect of particle gradation characteristics on yield stress of cemented paste backfill

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International Journal of Minerals,Metallurgy and Materials 2020年第1期27卷 10-17页

作者： Hai-yong Cheng shun-chuan Wu xiao-qiang Zhang Ai-xiang Wu Faculty of Land Resources Engineering Kunming University of Science and TechnologyKunming 650093China Key Laboratory of Ministry of Education of China for Efficient Mining and Safety of Metal Mines Beijing 100083China

Along with slurry concentration and particle density,particle size distribution(PSD)of tailings also exerts a significant influence on the yield stress of cemented paste,a non-Newtonian *** this work,a paste stability coefficient(PSC)was proposed to characterize paste gradation and better reveal its connection to yield *** coefficient was proved beneficial to the construction of a unified rheological model,applicable to different materials in different mines,so as to promote the application of rheology in the pipeline transportation of *** the results,yield stress showed an exponential growth with increasing PSC,which reflected the proportion of solid particle concentration to the packing density of granular media in a unit volume of slurry,and could represent the properties of both slurry and granular *** was found that slurry of low PSC contained extensive pores,generally around 20μm,encouraging free flow of water,constituting a relatively low yield *** contrast,slurry of high PSC had a compact and quite stable honeycomb structure,with pore sizes generally<5μm,causing the paste to overcome a higher yield stress to flow.

关键词： paste backfill grading theory yield stress paste stability coefficient microscale

Solvent polarity-induced photoluminescence enhancement (SPIPE): A method enables several-fold increase in quantum yield of silicon nanoparticles

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Nano Research 2019年第2期12卷 315-322页

作者： xiao-Bin Shen Bin Song Bei Fang xiao Yuan You-yong Li shun-Yi Wang shun-Jun Ji Yao He Laboratory of Nanoscale Biochemical Analysis Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Institute of Functional Nano and Soft Materials (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science and Technology (NANO-CIC) Soochow University Suzhou 215123 China Key Laboratory of Organic Synthesis of Jiangsu Province College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou 215123 China

Fluorescent silicon nanoparticles (SiNPs) bring exciting opportunities for long-awaited silicon-based optical application, while intrinsic indirect band gap of silicon severely limits photoluminescent quantum yield (PLQY) of SiNPs. To address this critical issue, we herein demonstrate a facile and general method, Le., solvent polarity-induced photoluminescence enhancement (SPIPE)1 yielding several-fold increase in quantum yield (QY) of SiNPs. Typically, different kinds of 4-substituented-1,8-naphthalic anhydride molecules, Le., 4-Br-1,8-naphthalic anhydride (BNA)1 4-triphenylamino-1,8-naphthalic anhydride (TPNA)1 and 4-dimethylamino-1,8-naphthalic anhydride (DMNA)1 are rationally designed and synthesized, which serve as surface ligands for the production of BNA-, TPNA-, and DMNA-capped small-sized (diameter:- 3.8-5.8 nm) SiNPs with QY of^8%,~15%,~16%, respectively. Of particular significance, QY of the resultant SiNPs could be greatly enhanced from^10% to^50% through the SPlPE strategy. Taken together with the theoretical calculation and the results of time-correlated single photon counting, we reveal that actived excited-state charge transfer interactions between surface-covered ligand and silicon oxide coating would be responsible for the observed QY enhancement. Moreover, other five kinds of solvents (i.e., methanol, isopropanol, dimethyl sulfoxide, N,N-dimethylformamide, and acetonitrile) are further employed for the SiNPs treatment, and similar improvement of QY values are observed, convincingly demonstrating the universal evidence of SPIPE of the SiNPs.

关键词： silicon nanoparticles quantum yield fluorescent surface ligand solvent polarity

The Hilbert expansion of the Boltzmann equation in the incompressible Euler level in a channel

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Science China Mathematics 2025年第1期 39-88页

作者： Feimin Huang Weiqiang Wang yong Wang Feng xiao Academy of Mathematics and Systems Science Chinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences Key Laboratory of Computing and Stochastic Mathematics (Ministry of Education) School of Mathematics and StatisticsHunan Normal University

The study of the hydrodynamic limit of the Boltzmann equation with physical boundary is a challenging problem due to the appearance of the viscous and Knudsen boundary *** this paper,the hydrodynamic limit from the Boltzmann equation with the specular reflection boundary condition to the incompressible Euler equations in a channel is *** on the multi-scaled Hilbert expansion,the equations with boundary conditions and compatibility conditions for interior solutions,and viscous and Knudsen boundary layers are derived under different scaling,***,some uniform estimates for the interior solutions,and viscous and Knudsen boundary layers are *** the help of the L2-L∞framework and the uniform estimates obtained above,the solutions to the Boltzmann equation are constructed by the truncated Hilbert expansion with multiscales,and hence the hydrodynamic limit in the incompressible Euler level is justified.

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Microstructure and mechanical properties of twin-wire arc sprayed Ni-Al composite coatings on 6061-T6 aluminum alloy sheet

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International Journal of Minerals,Metallurgy and Materials 2014年第5期21卷 469-478页

作者： Ji-xiao Wang Jing-shun Liu Lun-yong Zhang Jian-fei Sun Zhi-ping Wang School of Materials Science and Engineering Harbin Institute of Technology Harbin Welding Institute China Academy of Machinery Science & Technology School of Materials Science and Engineering Inner Mongolia University of Technology National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering Nanjing University College of science Civil Aviation University of China

We have systematically studied the microstructure and mechanical properties of Ni-5wt%Al and Ni-20wt%Al composite coat- ings fabricated on 6061-T6 aluminum alloy sheet by twin-wire arc spraying under different experimental conditions. The abrasive wear be- havior and interface diffusion behavior of the composite coatings were evaluated by dry/wet rubber wheel abrasive wear tests and heat treat- ment, respectively. Experimental results indicate that the composite coatings exhibit features of adhesive wear. Besides, the Vickers micro- hardness of NiA1 and Ni3AI intermetallic compounds is relatively larger than that of the substrate, which is beneficial for enhancing the wear resistance. With the increase of annealing temperature and time, the interface diffusion area between the Ni-Al coating and the substrate gradually expands with the formation of NiAl3 and Ni2Al3 phases, and is controlled by diffusion of aluminum atoms. The grain growth ex- ponent n of diffusion kinetics of the Ni-Al coating, calculated via a high-temperature diffusion model at 400, 480, and 550℃, is between 0.28 and 0.38. This satisfies the cubic law, which is consistent with the general theoretical relationship of high-temperature diffusion.

关键词： composite coatings intermetallics spraying aluminum alloys mechanical properties diffusion

Activation Energy for Superplastic Flow Above Critical Temperature of Die Steels

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Journal of Iron and Steel Research International 2006年第5期13卷 4-6页

作者： WEN Jiu-ba ZHANG Ke-ke CHEN Fu-xiao YANG yong-shun School of Materials Science and Engineering Henan University of Science and Technology Luoyang 471003 Henan China

Some commercial cold working die steels C.,Cr15 and CrWMn with ultra fine grain size were chosen as tested materials to research the activation energy for superplastic flow at different temperatures and strain rates above critical temperature. Based on the Arrhenius equation, the activation energy for superplastic flow is evaluated. The activation energy at constant strain rate is estimated by the logσ, vs 1/T relationship. The results show that the ac tivation energy is usually small under the conditions of optimal flow. The characteristics of superplastic deformation of steels above the critical temperature were also analyzed.

关键词： superplasticity superplastic working activation energy

Extension of Variable Separable Solutions for Nonlinear Evolution Equations

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Communications in Theoretical Physics 2008年第4期49卷 829-832页

作者： ZHANG shun-Li ZHU xiao-Ning WANG yong-Mao LOU Sen-Yue Center for Nonlinear Studies Department of Mathematics Northwest University Xi＇an 710069 China Department of Physics Shanghai Jiao Tong University Shanghai 200030 China Center of Nonlinear Science Ningbo University Ningbo 315211 China School of Science Xi＇an Jiaotong University Xi＇an 710049 China

We give the generalized definitions of variable separable solutions to nonlinear evolution equations, and characterize the relation between the functional separable solution and the derivative-dependent functional separable solution. The new definitions can unify various kinds of variable separable solutions appearing in references. As application, we classify the generalized nonlinear diffusion equations that admit special functional separable solutions and obtain some exact solutions to the resulting equations.

关键词： nonlinear evolution equation variable separable solution generalized conditional symmetry

Vibration of Timoshenko beam on hysteretically damped elastic foundation subjected to moving load

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Science China(Physics,Mechanics & Astronomy) 2015年第8期58卷 58-66页

作者： LUO WeiLi XIA yong WENG shun Department of Civil and Environmental Engineering The Hong Kong Polytechnic University School of Civil Engineering & Mechanics Huazhong University of Science and Technology

The vibration of beams on foundations under moving loads has many applications in several fields, such as pavements in highways or rails in railways. However, most of the current studies only consider the energy dissipation mechanism of the foundation through viscous behavior; this assumption is unrealistic for soils. The shear rigidity and radius of gyration of the beam are also usually excluded. Therefore, this study investigates the vibration of an infinite Timoshenko beam resting on a hysteretically damped elastic foundation under a moving load with constant or harmonic amplitude. The governing differential equations of motion are formulated on the basis of the Hamilton principle and Timoshenko beam theory, and are then transformed into two algebraic equations through a double Fourier transform with respect to moving space and time. Beam deflection is obtained by inverse fast Fourier transform. The solution is verified through comparison with the closed-form solution of an Euler-Bernoulli beam on a Winkler foundation. Numerical examples are used to investigate:(a) the effect of the spatial distribution of the load, and(b) the effects of the beam properties on the deflected shape, maximum displacement, critical frequency, and critical velocity. These findings can serve as references for the performance and safety assessment of railway and highway structures.

关键词： vibration beam-foundation system moving load

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爆炸切割网络传爆中的间隙与角度效应

火工品 2025年第1期 37-43页

作者：周晓鹏姜勇袁航中国船舶集团有限公司第七一三研究所河南郑州450015 河南省水下智能装备重点实验室河南郑州450015

为研究爆炸切割网络中传爆节点处传爆能力的关键影响因素,通过改变切割索对传爆药柱的传爆间隙进行了平板传爆试验,将试验结果结合仿真分析确定了JO-11C传爆药柱的仿真材料参数,并进一步分析了传播角度对传爆能力的影响。研究结果表明:... 详细信息

为研究爆炸切割网络中传爆节点处传爆能力的关键影响因素,通过改变切割索对传爆药柱的传爆间隙进行了平板传爆试验,将试验结果结合仿真分析确定了JO-11C传爆药柱的仿真材料参数,并进一步分析了传播角度对传爆能力的影响。研究结果表明:随着传爆间隙的增加,传爆能力下降,切割索对传爆药柱的最大传爆间隙区间为2.0~2.5 mm;同时,传爆角度的增大能够显著提高传爆能力。本研究为爆炸切割网络的传爆性能研究以及提高武器系统的可靠性提供了参考。

关键词：爆炸切割网络传爆间隙传爆角度传爆药柱仿真分析

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