SOLUTION TO A PARAMETRIC EQUATION WITH GENERALIZED BOUNDARY CONDITION IN TRANSPORT THEORY

This paper deals with the solution of a parametric equation with generalized boundary condiiton in transport theory. It gives the distribution of parameter (so called delta-eigenvalue [1]) with which the equation has non-zero solution. A necessary and sufficient condition for the existence of; he control critical eigenvalue delta0 is established.

SOLUTION TO A PARAMETRIC EQUATION IN TRANSPORT THEORY

In 1976, Ronen et al. raised the question of how to solve the new integrodifferential parameter equation with transport theory. So far there have only been some approximate calculations and numerical analyses about this question. Using functional analysis, this note discusses this question in a strict mathematical way, gives the parameter distribution in L^p space (1≤p≤+∞) with which the

A Review on China’s Transportation Development Theory from the Perspective of Regional Economics

Transportation is the lifeline of human civilization and an important component of the infrastructure for economic growth.As transportation is closely related to regional economic development,the summarization of China's transportation development theory from the perspective of regional economics will be conducive to clarifying the relationships between transportation and regional economic development and providing basic theoretical support for regional economic research and policy application.From the perspective of regional economics,China’s transportation development theory falls into two categories:transportation resource allocations,and the interactions between transportation and economic development.In recent years,there has been a trend toward the integration of transportation development research with regional economic growth,and a deeper understanding of the relationships between them has been achieved.

Nanofluids Transport Model Based on Fokker-Planck Equation and the Convection Heat Transfer Calculation

In current research about nanofluid convection heat transfer, random motion of nanoparticles in the liquid distribution problem mostly was not considered. In order to study on the distribution of nanoparticles in liquid, nanofluid transport model in pipe is established by using the continuity equation, momentum equation and Fokker-Planck equation. The velocity distribution and the nanoparticles distribution in liquid are obtained by numerical calculation, and the effect of particle size and particle volume fraction on convection heat transfer coefficient of nanofluids is analyzed. The result shows that in high volume fraction （ 0 _-- 0.8% ）, the velocity distribution of nanofluids characterizes as a ＂cork-shaped＂ structure, which is significantly different from viscous fluid with a parabolic distribution. The convection heat transfer coefficient increases while the particle size of nanoparticle in nanofluids decreases. And the convection heat transfer coefficient of nanofluids is in good agreement with the experimental result both in low （0 ~〈 0.1% ） and high （ q = 0.6% ） volume fractions. In presented model, Brown motion, the effect of interactions between nanoparticles and fluid coupling, is also considered, but any phenomenological parameter is not introduced. Nanoparticles in liquid transport distribution can be quantitatively calculated by this model.

Theoretical investigation of the thermoelectric transport properties of BaSi_2

The full-potential linear augmented plane wave method based on density functional theory is employed to investigate the electronic structure of BaSi2. With the constant relaxation time and rigid band approximation, the electrical conductivity, Seebeck coefficient and figure of merit are calculated by using Boltzmann transport theory, further eval- uated as a function of carrier concentration. We find that the Seebeck coefficient is more anisotropic than electrical conductivity. The figure of merit of BaSi2 is predicted to be quite high at room temperature, implying that optimal doping may be an effective way to improve thermoelectric properties.

Macroscopic lasereplasma interaction under strong non-local transport conditions for coupled matter and radiation

Reliable simulations of laseretarget interaction on the macroscopic scale are burdened by the fact that the energy transport is very often non-local.This means that the mean-free-path of the transported species is larger than the local gradient scale lengths and transport can be no longer considered diffusive.Kinetic simulations are not a feasible option due to tremendous computational demands,limited validity of the collisional operators and inaccurate treatment of thermal radiation.This is the point where hydrodynamic codes with non-local radiation and electron heat transport based on first principles emerge.The simulation code PETE(Plasma Euler and Transport Equations)combines both of them with a laser absorption method based on the Helmholtz equation and a radiation diffusion scheme presented in this article.In the case of modelling ablation processes it can be observed that both,thermal and radiative,transport processes are strongly non-local for laser intensities of 10^(13) W=cm^(2) and above.In this paper simulations for various laser intensities and different ablator materials are presented,where the non-local and diffusive treatments of radiation transport are compared.Significant discrepancies are observed,supporting importance of non-local transport for inertial confinement fusion related studies as well as for pre-pulse generated plasma in ultra-high intensity laseretarget interaction.

Charge Transport Properties of Tetrabenz[a,c,h,j]-anthracene Derivatives

Charge transport properties of F, OH, OCH3, SH and SCH3-substituted tetra- benz[a,c,h,j]- anthracene derivative molecules have been investigated theoretically at the B3LYP/6-31G＊＊ level using Marcus theory. The results showed that at 300 K, the hole or electron transport capability of F or SH-substituted molecules was better obviously than that of OH or OCH3-substituted molecules, The electron transport capability of SCH3-substituted and F or SH-substituted molecules was superior to their hole transport capability, respectively. F, SH or SCH3-substituted tetrabenz[a,c,h,j]-anthracene derivative molecules can be used as electron transport materials.

Theoretical Investigation on the Charge Transport Properties of 2,5-Di(cyanovinyl)-thiophene/furan with the Kinetic Monte Carlo Method

Exploring, designing, and synthesizing novel organic field-effect transistor （OFET） materials have kept an important and hot issue in organic electronics. In the current work, the charge transport properties for 2,5-di（cyanovinyl）thiophene/furan crystal associating two pentafluorophenyl units linked via the azomethine bond, CTE and CFE have been theoretically investigated by means of density functional theory （DFT） calculations coupled with the incoherent charge-hopping mechanism and the kinetic Monte Carlo simulation. Results show that these two compounds possess remarkably low-lying HOMO （-7.0 eV） and LUMO （-4.0 eV） levels, as well as large electron affinities （〉 3.0 eV）, which indicate their high stability exposed to air as promising OFET materials. However, the ph value at room temperature （T = 300 K） is predicted to be 2.058x10^7 cm26Vl·s-1, and the is as low as 9.834^10-8 cm2-V-l.s-1 for CFT crystal. Meanwhile, these two values are 7.561 x 10-8 and 8.437 x 10-8 cm2.V-I.s-1 for the CFE crystal, respectively. Furthermore, the simulation of angle-dependent mobility in the a-b, a-c, and b-c crystal planes shows that the charge transport in CTE and CFE crystals is remarkably anisotropic, which maybe is helpful for the fabrication of high-performance OFET devices.

Spin-dependent transport characteristics of nanostructures based on armchair arsenene nanoribbons

By employing non-equilibrium Green＇s function combined with the spin-polarized density-functional theory, we investigate the spin-dependent electronic transport properties of armchair arsenene nanoribbons（a As NRs）. Our results show that the spin-metal and spin-semiconductor properties can be observed in a As NRs with different widths. We also find that there is nearly 100% bipolar spin-filtering behavior in the a As NR-based device with antiparallel spin configuration. Moreover, rectifying behavior and giant magnetoresistance are found in the device. The corresponding physical analyses have been given.

High frequency S wave envelope synthesis using a multiple non-isotropic scattering model: application to aftershocks from the 2008 Wenchuan earthquake

Based on the formulation of a multiple non-isotropic scattering process, a characteristic source time is introduced to define the initial impulse width of energy density at the source. An analytical expression of the initial intensity spectral density of a seismic wave is incorporated into the integral equation of seismic wave energy density. And, a recursive formula of Green＇s function is derived to obtain the higher order Green＇s function, which is included to describe the stronger non-isotropic scattering process. Then, the effect of the scattering pattern on the energy density envelope is investigated by the modified scattering theory. Significant differences arc found in the decay of the energy density envelopes with distances using different scattering patterns. The envelope synthesized by the forward dominated scattering pattern is larger than the results obtained by the isotropic and backward dominated scattering pattern. Different scattering patterns are also used to fit the observation data from the aftershocks of the 2008 Wenchuan earthquake. It is concluded that the envelopes synthesized by the forward scattering pattern can match the data better than the isotropic and backward dominated scattering cases, and a new interpretation of the coda wave is given. Finally, using the forward dominated scattering pattern, the envelope broadening of the observed data is reproduced.

Damaging impacts of energetic charge particles on materials in plasma energy explosive events

To provide some reference data for estimation of the erosion rates and lifetimes of some candidate plasma facing component （PFC） materials in the plasma stored energy explosive events （PSEEE）, this paper calculates the sputtering yields of Mo, W and deuterium saturated Li surface bombarded by energetic charged particles by a new sputtering physics description method based on bipartition model of charge particle transport theory. The comparisons with Monte Carlo data of TRIM code and experimental results axe made. The dependences of maximum energy deposition, particle and energy reflection coefficients on the incident energy of energetic runaway electrons impinging on the different material surfaces are also calculated. Results may be useful for estimating the lifetime of PFC and analysing the impurity contamination extent, especially in the PSEEE for high power density and with high plasma current fusion reactor.

Anisotropic phonon thermal transport in two-dimensional layered materials

Two-dimensional layered materials(2DLMs)have attracted growing attention in optoelectronic devices due to their intriguing anisotropic physical properties.Different members of 2DLMs exhibit unique anisotropic electrical,optical,and thermal properties,fundamentally related to their crystal structure.Among them,directional heat transfer plays a vital role in the thermal management of electronic devices.Here,we use density functional theory calculations to investigate the thermal transport properties of representative layered materials:β-InSe,γ-InSe,MoS2,and h-BN.We found that the lattice thermal conductivities ofβ-InSe,γ-InSe,MoS_(2),and h-BN display diverse anisotropic behaviors with anisotropy ratios of 10.4,9.4,64.9,and 107.7,respectively.The analysis of the phonon modes further indicates that the phonon group velocity is responsible for the anisotropy of thermal transport.Furthermore,the low lattice thermal conductivity of the layered InSe mainly comes from low phonon group velocity and atomic masses.Our findings provide a fundamental physical understanding of the anisotropic thermal transport in layered materials.We hope this study could inspire the advancement of 2DLMs thermal management applications in next-generation integrated electronic and optoelectronic devices.

THEORY AND CONSERVATION THEOREM OF VORTICITY FLUX IN TRANSPORT

According to the theory of the transport and vorticity dynamics,the paper establishes the theory of vorticity flux and the conservation theorem between the vorticity flux and vortex strength in a plane flow.The theory of vorticity flux is a basic one in research on turbulence.

Three methods for the single-photon transport in a chiral cavity quantum electrodynamics system

We investigate the single-photon transport problem in the system of a whispering-gallery mode microresonator chirally coupled with a two-level quantum emitter[QE].Conventionally,this chiral QE-microresonator coupling system can be studied by the master equation and the single-photon transport methods.Here,we provide a new approach,based on the transfer matrix,to assess the single-photon transmission of such a system.Furthermore,we prove that these three methods are equivalent.The corresponding relations of parameters among these approaches are precisely deduced.The transfer matrix can be extended to a multiple-resonator system interacting with two-level QEs in a chiral way.Therefore,our work may provide a convenient and intuitive form for exploring more complex chiral cavity quantum electrodynamics systems.

Theoretical investigations of transport properties of organic solvents in cation-functionalized graphene oxide membranes： Implications for drug delivery

We perform detailed quantum chemical calculations to elucidate the origin and mechanism of the selective permeability of alkali and alkaline earth cation- decorated graphene oxide （M-GO） membranes to organic solvents. The results show that the selectivity is associated mainly with the transport properties of solvents in the membranes, which depends on two regions of the flow path： the sp3 C-O matrix of the GO sheets and the cation at the center of the hexagon rather than the sp~ region. According to the delocalization of ~ states in sp2 regions, we propose a design guide for high-quality M-GO membranes. The solvent-cation interaction essentially causes directional transport of molecules in the M-GO membranes under the transmembrane pressure, indicating a site-to-site mech- anism. The solvent-sp3 C-O matrix interaction may inhibit molecular transport between two fixed cations by consuming energy. The competition between energy consumption by the solvent-cation interaction and energy expenditure by the solvent-sp3 C-O matrix interaction leads to various transport properties of solvents and thus allows for the selective permeability of the M-GO membranes. Findings from the study are helpful for the future design of multifunctional M-GO macro-membranes as cost-effective solution nanofilters in chemical, biological, and medical applications

Theoretical characterization of hole mobility in BTBPD

（ E）-5,5＇-Bis（ 5-（ benzo[ b ]thiophen- 2-yl ）thiophen-2-yl ）-1,1＇-bis（ 2-ethylhexyl ）-[ 3,3＇-bipyrrolylidene ]- 2,2＇（1H, l＇H）-dione （BTBPD） has been reported by Zhang and co-workers. To further understand the charge-transporting nature of BTBPD, the density-functional theory （DFF） and the Marcus charge transfer theory were performed. The character of the frontier molecular orbitals, reorganization energies and transfer integrals in different directions were considered in details. The results revealed that the BTBPD has high hole transport efficiency （μ = 0.29 cm2 V-1 s-1 ）. The intermolecular π-π interaction and S...S interaction provide the holes transport channels.

High performance solid-state thermoelectric energy conversion via inorganic metal halide perovskites under tailored mechanical deformation

Solid-state thermoelectric energy conversion devices attract broad research interests because of their great promises in waste heat recycling,space power generation,deep water power generation,and temperature control,but the search for essential thermoelectric materials with high performance still remains a great challenge.As an emerging low cost,solution-processed thermoelectric material,inorganic metal halide perovskites CsPb(I_(1–x)Br_(x))_(3) under mechanical deformation is systematically investigated using the first-principle calculations and the Boltzmann transport theory.It is demonstrated that halogen mixing and mechanical deformation are efficient methods to tailor electronic structures and charge transport properties in CsPb(I_(1–x)Br_(x))_(3) synergistically.Halogen mixing leads to band splitting and anisotropic charge transport due to symmetry-breakinginduced intrinsic strains.Such band splitting reconstructs the band edge and can decrease the charge carrier effective mass,leading to excellent charge transport properties.Mechanical deformation can further push the orbital energies apart from each other in a more controllable manner,surpassing the impact from intrinsic strains.Both anisotropic charge transport properties and ZT values are sensitive to the direction and magnitude of strain,showing a wide range of variation from 20%to 400%(with a ZT value of up to 1.85)compared with unstrained cases.The power generation efficiency of the thermoelectric device can reach as high as approximately 12%using mixed halide perovskites under tailored mechanical deformation when the heat-source is at 500 K and the cold side is maintained at 300 K,surpassing the performance of many existing bulk thermoelectric materials.

A Stabilized Finite Element Method for Modified Poisson-Nernst-Planck Equations to Determine Ion Flow Through a Nanopore

The conventional Poisson-Nernst-Planck equations do not account for the finite size of ions explicitly.This leads to solutions featuring unrealistically high ionic concentrations in the regions subject to external potentials,in particular,near highly charged surfaces.A modified form of the Poisson-Nernst-Planck equations accounts for steric effects and results in solutions with finite ion concentrations.Here,we evaluate numerical methods for solving the modified Poisson-Nernst-Planck equations by modeling electric field-driven transport of ions through a nanopore.We describe a novel,robust finite element solver that combines the applications of the Newton’s method to the nonlinear Galerkin form of the equations,augmented with stabilization terms to appropriately handle the drift-diffusion processes.To make direct comparison with particle-based simulations possible,our method is specifically designed to produce solutions under periodic boundary conditions and to conserve the number of ions in the solution domain.We test our finite element solver on a set of challenging numerical experiments that include calculations of the ion distribution in a volume confined between two charged plates,calculations of the ionic current though a nanopore subject to an external electric field,and modeling the effect of a DNA molecule on the ion concentration and nanopore current.

Statistical properties of pseudo-particle systems

Pseudo-particle modeling （PPM）, a molecular modeling method which combines time-driven algorithms and hard molecule modeling, was originally developed for simulating gas in complex multiphase systems （Ge ＆ Li, 2003; Ge et al., 2005; Ge, 1998）. In this work, the properties of two- and three-dimensional pseudo-particle systems, namely, mean free path, compressibility factor, self-diffusion coefficient and shear viscosity, are systematically measured by using PPM. it is found that in terms of an effective diameter, the results well conform to the Chapman-Enskog theory, thus suggesting that PPM can be employed to simulate the micro- and meso-scale behavior of ordinary gas and fluid flows.

Electrical contacts in monolayer blue phosphorene devices

Semiconducting monolayer （ML） blue phosphorene （BlueP） shares similar stability with ML black phosphorene （BP）, and it has recently been grown on an Au surface. Potential ML BlueP devices often require direct contact with metal to enable the injection of carriers. Using ab initio electronic structure calculations and quantum transport simulations, for the first time, we perform a systematic study of the interfacial properties of ML BlueP in contact with metals spanning a wide work function range in a field effect transistor （FET） configuration. ML BlueP has undergone metallization owing to strong interaction with five metals. There is a strong Fermi level pinning （FLP） in the ML BlueP FETs due to the metal-induced gap states （MIGS） with a pinning factor of 0.42. ML BlueP forms n-type Schottky contact with Sc, Ag, and Pt electrodes with electron Schottky barrier heights （SBHs） of 0.22, 0.22, and 0.80 eV, respectively, and p-type Schottky contact with Au and Pd electrodes with hole SBHs of 0.61 and 0.79 eV, respectively. The MIGS are eliminated by inserting graphene between ML BlueP and the metal electrode, accompanied by a transition from a strong FLP to a weak FLP. Our study not only provides insight into the ML BlueP-metal interfaces, but also helps in the design of ML BlueP devices.