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A Novel Dynamic Quadrature Scheme for Solving Boltzmann Equation with Discrete Ordinate and Lattice Boltzmann Methods

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Communications in Computational Physics 2012年第4期11卷 1397-1414页

作者： C.T.Hsu S.W.Chiang k.f.sin Department of Mechanical Engineering Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong

The Boltzmann equation(BE)for gas flows is a time-dependent nonlinear differential-integral equation in 6 *** current simplified practice is to linearize the collision integral in BE by the BGk model using Maxwellian equilibrium distribution and to approximate the moment integrals by the discrete ordinatemethod(DOM)using a finite set of velocity quadrature *** simplification reduces the dimensions from 6 to 3,and leads to a set of linearized discrete *** main difficulty of the currently used(conventional)numerical procedures occurs when the mean velocity and the variation of temperature are large that requires an extremely large number of quadrature *** this paper,a novel dynamic scheme that requires only a small number of quadrature points is *** is achieved by a velocity-coordinate transformation consisting of Galilean translation and thermal normalization so that the transformed velocity space is independent of mean velocity and *** enables the efficient implementation of Gaussian-Hermite *** velocity quadrature points in the new velocity space are fixed while the correspondent quadrature points in the physical space change from time to time and from position to *** this dynamic nature in the physical space,this new quadrature scheme is termed as the dynamic quadrature scheme(DQS).The DQS was implemented to the DOM and the lattice Boltzmann method(LBM).These new methods with DQS are therefore termed as the dynamic discrete ordinate method(DDOM)and the dynamic lattice Boltzmann method(DLBM),*** new DDOM and DLBMhave been tested and validated with several testing *** the same accuracy in numerical results,the proposed schemes are much faster than the conventional ***,the new DLBM have effectively removed the incompressible and isothermal restrictions encountered by the conventional LBM.

关键词： Dynamics quadrature dynamic discrete ordinatemethod dynamic lattice Boltzmann method thermal lattice Boltzmann method

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Second-order optimality conditions f or minimizing a maxfunction

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Science China Mathematics 2000年第7期43卷 722-733页

作者：黄力人 k.f.Ng Department of Mathematics South China Normal University Guangzhou 510631 China Department of Mathematics The Chinese University of Hong KongHong KongChina Correspondence should be addressed to K.F.Ng

We study Chaney's and Ben-Tal-Zowe's second-order directional derivatives with applications in minimization problem for max-functions of the formh(x): = max {f(x, τ); τ ∈T},where T is a compact metricspace. We impr... 详细信息

关键词： max-f unction sup-type function second-order optimality condition nonsmooth optimization.

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Merging bound states in the continuum in an open acoustic resonator

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 124-131页

作者： Lujun Huang Bin Jia Artem S.Pilipchuk Sibo Huang Chen Shen Almas f.Sadreev Yong Li Andrey E.Miroshnichenko School of Physics and Electronic Sciences East China Normal University Institute of Acoustics Tongji University L.V.kirensky Institute of Physics Department of Mechanical Engineering Rowan University School of Engineering and Technology University of New South Wales at Canberra

Bound states in the continuum （BICs） are perfectly localized resonances despite embedding in the continuum ***,an isolated BIC is very sensitive to the structure ***,we report merging acoustic BICs in a single open resonator,robust against the structure *** find that both symmetry-protected BIC and friedrich-Wintgen BIC are sustained in a single coupled waveguide-resonator *** varying the height and length of the resonator,these two BICs move toward each other and merge into a single one at a critical *** to an individual BIC,the merged BIC is robust against fabrication error because its Q-factor is proportional to ΔL-4,whereΔL embodies the structure *** essence of this extraordinary phenomenon is perfectly explained by the two-and three-level approximations of the effective nonHermitian ***,we present direct experimental demonstrations of the moving and merging of BICs in a coupled 3D waveguide-resonator,which are evidenced by the vanishing of the linewidth of fano resonance in the transmission *** results may find exciting applications in designing high-quality acoustic sources,sensors and filters.

关键词： acoustic resonances bound state in the continuum high-Q resonances

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Biofuel-driven trigeneration systems for non-residential building applications:A holistic assessment from the energy,environmental and economic perspectives

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Building Simulation 2023年第4期16卷 557-576页

作者： k.f.fong C.k.Lee Division of Building Science and Technology College of EngineeringCity University of Hong KongTat Chee AvenueKowloonHong KongChina

In the metropolises,it is unlikely to use merely solar and wind energy to pursue zero carbon building ***,it would become possible if biofuel-driven trigeneration systems(BDTS)are *** is thus essential to assess the application opportunity of BDTS in a holistic *** this study,BDTS offered definite primary energy saving of up to 15%and carbon emissions reduction of at least 86%in different types of non-residential buildings as compared to the conventional *** 24/7 operation for the hotel and hospital buildings,the corresponding BDTS could even achieve zero carbon *** the BDTS primed with compression-ignition internal combustion engine were not economically viable even in running cost due to the high local biodiesel price *** BDTS primed with spark-ignition engine and fueled by biogas,however,would have economic merit when carbon price was considered for the conventional systems that fully utilize fossil *** of carbon tax and social cost could have the payback ceilings of 8 years and 2 years respectively for most of building ***,the results could reflect the application potential of BDTS for non-residential buildings,leading the pathway to carbon neutrality for sustainable sub-tropical cities.

关键词： trigeneration biofuel dynamic simulation carbon tax social cost economic analysis

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On Product-Cordial Index Sets and friendly Index Sets of 2-Regular Graphs and Generalized Wheels

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Acta Mathematica sinica,English Series 2012年第4期28卷 661-674页

作者： Harris kWONG sin Min LEE Ho kuen NG Department of Mathematical Science SUNY Fredonia Department of Computer Science San Jose State University Department of Mathematics San Jose State University

A vertex labeling f ： V →Z2 of a simple graph G = （V, E） induces two edge labelings The friendly index set and the product-cordial index set of G are defined as the setsf is friendly}. In this paper we study and determine the connection between the friendly index sets and product-cordial index sets of 2-regular graphs and generalized wheel graphs.

关键词： friendly index set product cordial index set 2-regular graphs generalized wheels

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Teleportation of unknown states of a qubit and a single-mode field in strong coupling regime without Bell-state measurement

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Communications in Theoretical Physics 2023年第2期75卷 73-79页

作者： f Jahanbakhsh M k Tavassoly Optics and Laser Group Faculty of PhysicsYazd UniversityYazd 89195-741Iran

In this paper,we develop the teleportation scheme in[Zheng in Phys Rev A 69,064302,2004],in the sense that,we work in the strong atom-field coupling regime wherein the rotating wave approximation(RWA)is no longer *** achieve the purpose,a scheme consisting of a qubit interacting with a single-mode quantized field is described via the Rabi model(counter rotation terms are taken into account).Our first aim is to teleport an unknown atomic state of a qubit(which interacts with the quantized field in a cavity)to a second qubit(exists in another distant cavity field),beyond the RWA and without the Bell-state measurement *** the continuation,in a similar way,we teleport an unknown state of a single-mode field *** fact,it is shown that,in this regime,after applying some particular conditions,containing the interaction time of atom-field in the cavities,adjusting the involved frequencies,as well as the atom-field coupling in the model,if a proper measurement is performed on the state of the first qubit(the related field in the cavity),the unknown states of the qubit(field)can be teleported from the first qubit(cavity field)to the second qubit(cavity field),*** show that in both considered cases,the teleportation protocol is successfully performed with the maximum possible fidelity,1,and the acceptable success probability,0.25.

关键词： strong atom-field coupling Rabi model quantum teleportation success probability fidelity

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Synthesis and Crystal Structure of a New Potassium Yttrium Diphosphate Dihydrate kYP_2O_7·2H_2O

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Chinese Journal of Structural Chemistry 2008年第10期27卷 1199-1204页

作者： férid M Horchani-Naifer k Unité de Recherches de Matériaux de Terres Rares Centre National de Recherches en Sciences des MatériauxB.P.95 Hammam-Lif 2050Tunisie

The dihydrated potassium yttrium diphosphate, kYP2O7·2H2O, has been synthesized for the first time. single-crystal XRD study has allowed the determination of its structure and correct formula. It crystallizes in the monoclinic system, space group P21/c, with the cell parameters a = 7.7069（3）, b = 10.5801（4）, c = 10.0204（5）A,β = 93.24（3）A, V= 815.76（6）A^3, Z= 4, Mr = 337.98, f（000） = 656, Dc = 2.752 g/cm^3 and/t = 8.073 mm^-1. The single-crystal structure was solved from 1856 unique reflections with the final R = 0.0365 and wR = 0.0772, refined with 119 parameters. The atomic arrangement of kYP2O7·2H2O is built by the P2O7 groups, the YO7 and the kO10 polyhedrons which are connected by corner and edge-sharing to form a three-dimensional framework. Water molecules are directly bonded to the Y and k atoms, and they are located in channels running along the a direction.

关键词： crystal structure yttrium diphosphate infrared spectrum TGA-DTA analysis

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Parrondo's paradox for chaos control and anticontrol of fractional-order systems

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Chinese Physics B 2016年第1期25卷 507-513页

作者： Marius-f Danca Wallace k S Tang Department of Mathematics and Computer Science Avram Iancu University Romanian Institute for Science and Technology Department of Electronic Engineering City University of Hong Kong

We present the generalized forms of Parrondo＇s paradox existing in fractional-order nonlinear systems. The gener- alization is implemented by applying a parameter switching （PS） algorithm to the corresponding initial value problems associated with the fractional-order nonlinear systems. The PS algorithm switches a system parameter within a specific set of N 〉 2 values when solving the system with some numerical integration method. It is proven that any attractor of the concerned system can be approximated numerically. By replacing the words ＂winning＂ and ＂loosing＂ in the classical Parrondo＇s paradox with ＂order＂ and ＂chaos＂, respectively, the PS algorithm leads to the generalized Parrondo＇s paradox： chaos1 ＋ chaos2 ＋..- ＋ chaosN = order and order1 ＋ order2 ＋.-. ＋ orderN = chaos. finally, the concept is well demon- strated with the results based on the fractional-order Chen system.

关键词： Parrondo's paradox chaos control parameter switching algorithm fractional-order Chen system

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Extensive spectral tuning of the proton transfer emission from green to red via a rational derivatization of salicylideneaniline

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Chinese Chemical Letters 2012年第11期23卷 1279-1282页

作者： Hsing Yang Tsai sin kai fang kew Yu Chen Department of Chemical Engineering Feng Chia University

A series of salicylideneaniline derivatives 1a-lf were synthesized under mild condition in high yields, and characterized by ^1H NMR, HRMS, UV-vis and emission spectra. In solid and aprotic solvents 1a-1f exist mainly as E conformers that possess a sixmembered-ring hydrogen bond and undergo excited-state intramolecular proton transfer （ESIPT） reactions, resulting in a protontransfer tautomer emission. Depending on the electronic donor or acceptor strength of the substituent in either the HOMO or LUMO site, a broad tuning range of the emission from green （1c） to red （1a） has been achieved.

关键词： ESIPT Schiff bases Salicylideneaniline derivatives Db'T calculations

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The theoretical study of the efficiency of diffusion deposition of nanoaerosols in the extended range of the Peclet numbers

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Particuology 2023年第6期77卷 47-55页

作者： R.f.Mardanov S.k.Zaripov V.f.Sharafutdinov N.I.Lobachevskii Institute of Mathematics and Mechanics Kazan(Volga Region)Federal UniversityKremlevskaya ul.18KazanTatarstan420008Russia

The efficiencies of the diffusion deposition of nanoaerosols for a single fiber for the models of aerosol filter and wire mesh screen are studied numerically in the extended range of the Peclet number *** rectangular periodic cell model for fluid flow and convective-diffusive transport of small aerosol particles is *** of the previous theoretical and experimental studies of single fiber diffusion deposition efficiency were for the case of Pe>*** array with uniform square or chess grid of fibers and of a row of circular cylindrical fibers are considered as the filter and wire mesh screen *** flow and particles transport equations are solved numerically using the Boundary Element *** obtained numerical data are used to derive the approximate formulas for the deposition efficiency in the entire range of the Peclet number for the various porosities of the filter medium or distances between fibers in a wire mesh *** derived dependencies take into account nonlinearity of the deposition efficiency at the low Peclet *** obtained analytical dependencies compare well with the numerical and experimental data.

关键词： Arrayof fibers Row of fibers Periodic cell model Convection-diffusion equation single fiber efficiency

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