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Collisionless tool orientation smoothing above blade stream surface using NURBS envelope

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第3期14卷 187-197页

作者： Jing-hua XU Shu-you ZHANG Jian-rong TAN ri-na sa State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

In five-axis machining,tool orientation above a blade stream surface may lead to tool collision and a decrease in workpiece ***,collisionless tool orientation smoothing(TOS)becomes an important *** the basis of a constant scallop height tool path,the triangular facets in the faces,vertices format are constructed from cutter contact(CC)using the Voronoi incremental *** cutter location(CL)points candidate set is represented by an oblique elliptic cone whose vertex lies at CC using NURBS *** the CL point is above its CC is judged by the dot product between the normal vector and the point on triangulation nearest to the CL *** curvatures at CC are obtained by fitting a moving least square(MLS) quadratic patch to the local neighborhood of a vertex and calculating eigenvectors and eigenvalues of the Hessian *** surface elastic energy is employed as the weight in selection from the NURBS *** collision is judged by NURBS surface *** can then be expressed by selecting a CL point for each CC point and converted into a numerical control(NC)code automa.ically according to the postprocessor type of the machine *** proposed method is verified by finishing of a cryogenic turboexpander impeller of air separation equipment.

关键词： Tool orientation smoothing(TOS) Blade stream surface Triangular facet NURBS envelope Surface elastic energy

Localized nonlinear waves in a myelinated nerve fiber with self-excitable membrane

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Chinese Physics B 2023年第2期32卷 150-162页

作者： Nkeh oma.Nfor Patrick Guemkam Ghomsi Francois Marie Moukam Kakmeni Department of Physics HTTC BambiliUniversity of BamendaP.P.Box 39 BambiliCameroon Complex Systems and Theoretical Biology Group Laboratory of Research on Advanced Materials and Nonlinear Science(LaRAMaNS)Department of PhysicsFaculty of ScienceUniversity of BueaP.O.Box 63 BueaCameroon

We systematically study the evolution of modulated nerve impulses in a myelinated nerve fiber, where both the ionic current and membrane capacitance provide the necessary nonlinear feedbacks. This is achieved by using a perturbation technique, in which the Liénard form of the modified discrete Fitzhugh–Nagumo equation is reduced to the complex Ginzburg–Landau amplitude equation. Three distinct values of the capacitive feedback parameter are considered. At the critical value of the capacitive feedback parameter, it is shown that the dynamics of the system is governed by the dissipative nonlinear Schr?dinger equation. Linear stability analysis of the system depicts the instability of plane waves,which is manifested as burst of modulated nerve impulses that fulfills the Benjamin–Feir criteria. Variations of the capacitive feedback parameter generally influences the plane wave stability and hence the type of wave profile identified in the neural network. Results of numerical simulations mainly confirm the propagation, collision, and annihilation of nerve impulses in the myelinated axon.

关键词： myelinated nerve Fitzhugh–Nagumo capacitive feedback parameter Ginzburg–Landau collision annihilation

Investigation of bright and dark solitons in α,β-Fermi Pasta Ulam lattice

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Chinese Physics B 2021年第2期30卷 211-219页

作者： Nkeh oma.Nfor Serge Bruno Yamgoué Francois Marie Moukam Kakmeni Department of Physics Higher Teacher Training College BambiliThe University of BamendaP.O.Box 39Bambili-Cameroon Complex Systems and Theoretical Biology Group Laboratory of Research on Advanced Materials and Nonlinear Science(LaRAMaNS)Department of PhysicsFaculty of ScienceUniversity of BueaP.O.Box 63 Buea-Cameroon

We consider the Hamiltonian ofα,β-Fermi Pasta Ulam lattice and explore the Hamilton-Jacobi formalism to obtain the discrete equation of *** using the continuum limit approximations and incorporating some normalized parameters,the extended Korteweg-de Vries equation is obtained,with solutions that elucidate on the Fermi Pasta Ulam *** further derive the nonlinear Schrodinger amplitude equation from the extended Korteweg-de Vries equation,by exploring the reductive perturbative *** dispersion and nonlinear coefficients of this amplitude equation are functions of theαandβparameters,with theβparameter playing a crucial role in the modulational instability analysis of the ***βgreater than or equal to zero,no modulational instability is observed and only dark solitons are identified in the *** forβless than zero,bright solitons are traced in the lattice for some large values of the *** of numerical simulations of both the Korteweg-de Vries and nonlinear Schr¨odinger amplitude equations with periodic boundary conditions clearly show that the bright solitons conserve their amplitude and shape after collisions.

关键词： Fermi Pasta Ulam paradox bright dark

Assessing cooling energy reduction potentials by retrofitting traditional cavity walls into passively ventilated cavity walls

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Building Simulation 2021年第4期14卷 1295-1309页

作者： ri Na Zhigang Shen Department of Civil and Environmental Engineering University of DelawareNewarkDE19716USA The Durham School of Architecture Engineering and Construction University of Nebraska LincolnLincolnNE68588USA

A major roadblock in achieving substantial building energy reduction is the low performance of old buildings that account for a significant portion of the building energy *** low-cost energy retrofit solutions that do not disrupt occupants’daily life during the retrofitting is the key to successful building energy retrofit *** this paper,a novel and low-cost exterior wall retrofitting solution is introduced,and its performance in reducing space cooling load was quantitatively evaluated to demonstrate its feasibility and *** primary goal of this paper is to provide a quantitative assessment of the cooling-energy savings potential by using the proposed new wall *** intended retrofitting targets are the large amount of existing cavity-wall buildings located in hot climate *** quantification of the before-after heat-flux reduction was conducted through a 3-dimensional steady-state low turbulence computational fluid dynamics(CFD)model,which is validated by benchmarking its prediction against the published experimental case *** outcomes of the investigation suggest that this simple low-cost solution has great potentials in reducing buildings’summer cooling load in hot climate *** applicability of this solution is not limited to retrofitting existing *** energy-efficient building designs can also adopt this solution in their envelope systems.

关键词： low-cost energy retrofit building envelope cavity wall stack effect space cooling energy reduction CFD

Deep Learning for the Traffic Signs Classification based on Convolutional Neural Networks

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Deep Learning for the Traffic Signs Classification based on ...

作者： Epota oma.Estanislao 济南大学

学位级别：硕士

A Remark on Leray's Problem on Stationary Navier–Stokes Flows with Large Fluxes in Infinite Cylindrical Doma.ns

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Acta Mathematica Sinica,English Series 2015年第10期31卷 1571-1581页

作者： Myong-Hwan ri Institute of Mathematics State Academy of SciencesPyongyang DPR Korea

We consider Leray＇s problem on stationary Navier Stokes flows with arbitrary large fluxes in an unbounded cylinder with several exits to infinity. For a stationary Navier Stokes flow with large fluxes in the unbounded cylinder, we prove that, if the difference between the pressure of the main flow and the pressure of the Poiseuille flow with the same flux in a branch of the cylinder remains bounded at ｜x｜→∞, then the flow behaves at infinity of the branch like the Poiseuille flow.

关键词： Leray's problem Navier-Stokes equations large flux unbounded cylindrical doma.ns

Effects of Imposing Import Tariffs on a Country's Economic Growth-a Case Study on Malawi

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Effects of Imposing Import Tariffs on a Country's Economic G...

作者： TAPIWA RUTH NG'oma 河北大学

学位级别：硕士

There has been an ongoing debate as to whether there is any relationship betweenimposition of import tariffs and economic growth in developing countries. Thus, this paperaims at empirically and theoretically analysing the effects that imposition of import tariffs haveon economic growth in Malawi over the period of1982–2011. This relationship is examinedusing the Autoregressive Moving Average (AriMA) model which will test the effect of animplemented import tariff policy on GDP growth.The Autoregressive Moving Average regression results reveal that there is a relationshipbetween imposed import tariffs and economic growth in Malawi, that is, a reduction in theaverage import tariff rate leads to a rise in GDP growth. These results strongly support the role,import trade can play in Malawi’s economic development. This means that by adopting goodimport tariff policies, Malawi will eventually boost domestic production hence the GDPgrowth.

关键词： Import tariffs Economic growth and Malawi Revenue Authority

Regularity for 3D Navier–Stokes Equations Based on Energy Distribution at Wavenumber Bands

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Acta Mathematica Sinica,English Series 2019年第8期35卷 1377-1392页

作者： Myong-Hwan ri Institute of Mathematics State Academy of SciencesDPR Korea

We present some regularity criteria for the Leray–Hopf weak solutions to the Cauchy problem for 3D Navier–Stokes equations based on energy distribution at wavenumber bands. We show sufficient conditions for regularity based on the ratios of energy dissipation rates at sufficiently high wavenumber bands and neighboring medium wavenumber bands. Moreover, we give a regularity criterion based on relations between energy at high and low wavenumber bands.

关键词： Navier-Stokes equations global regularity energy transfer

First-principles simulation and experimental evidence for improvement of transmittance in ZnO films

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Progress in Natural Science:Materials International 2011年第1期21卷 40-45页

作者： ri-ichi MURAKAMI Department of Mechanical Engineering The University of Tokushima2-1 Minamijosanjima-choTokushima 770-8506Japan

ZnO/Ag/Glass films were prepared by a DC magnetron sputtering system,which exhibit both excellent properties of high conductivity and high ***,an enhancement of transmission of ZnO films was observed after brought into contact to a silver layer,but the understanding of experimental findings for the enhancement of transmission was ***,the first-principles simulations of electrical and optical properties were utilized using the density functional theory with local-density approximations or generalized-gradient *** crystal structure of ZnO or Ag was imported from the Material Studio *** periodic supercell has the same atomic ratio with the experimental structure and was optimized using the CASTEP package in Material *** to the calculation results,the enhancement in transmission is attributed to the surface plasmon polariton in the asymmetric structure films.

关键词： first-principles transparent conductive oxide ZnO transmittance surface plasmon polaritons