Nonlinear Flow Numerical Simulation of an Ultra-Low Permeability Reservoir

A nonlinear flow mathematical model is established and the grid equation is deduced. A nonlinear flow reservoir numerical simulation program is compiled. The permeability loss coefficient is used to describe the permeability loss. A pilot calculation is made on the basis of actual field data, which reflects the reservoir development characteristics. The numerical simulation program based on nonlinear flow can anticipate the dynamic characteristics of the ultra-low permeability reservoir exploitation more exactly.     

缺陷对Pt在石墨烯上吸附影响的研究

本文利用第一原理方法计算了空位缺陷和硼(B)掺杂时对Pt在graphene上吸附的影响.结果表明:Pt在graphene上吸附的稳定住置是Pt吸附在桥住;悬挂键的存在极大的增强了Pt在graphene空位处的吸附;B替住掺杂有利于Pt原子在杂质附近的吸附.     

Escape dynamics in collinear atomic-like three mass point systems

The present paper studies the escape mechanism in collinear three point mass systems with small-range-repulsive/large-range-attractive pairwise interaction. Specifically, we focus on the asymptotic behaviour for systems with non-negative total energy.On the zero energy level set there are two distinct asymptotic states, called 1+1+1escape configurations, where all the three separations infinitely increase as t→∞. We show that 1+1+1 escapes are improbable by proving that the set of initial conditions leading to such asymptotic configurations has zero Lebesgue measure. When the outer mass points are of the same kind we deduce the existence of a heteroclinic orbit connecting the 1+1+1 escape configurations. We further prove that this orbit is stable under parameter perturbation.In the positive energies’ case, we show that the set of initial conditions leading to 1+1+1 escape configurations has positive Lebesgue measure.     

Joint universality for dependent <Emphasis Type="Italic">L</Emphasis>-functions

We prove that, for arbitrary Dirichlet L-functions \(L(s;\chi _1),\ldots ,L(s;\chi _n)\) (including the case when \(\chi _j\) is equivalent to \(\chi _k\) for \(j\ne k\)), suitable shifts of type \(L(s+i\alpha _jt^{a_j}\log ^{b_j}t;\chi _j)\) can simultaneously approximate any given set of analytic functions on a simply connected compact subset of the right open half of the critical strip, provided the pairs \((a_j,b_j)\) are distinct and satisfy certain conditions. Moreover, we consider a discrete analogue of this problem where t runs over the set of positive integers.     

Non-Monotonic Behavior of One-Signed Solutions of Quasilinear Differential Equations

We consider a class of the second-order quasilinear differential equations. By deriving relations between certain types of monotonic solutions of the quasilinear equation and corresponding reciprocal half-linear equation on a finite interval (a, b), we obtain criteria for all solutions of the main equation, which do not change sign in (a, b), to be non-monotonic in (a, b). This work is also extended to a perturbed half-linear equation as well as to the half-line \((a,\infty )\).     

Collision and escape orbits in a generalized Hénon–Heiles model

The motion of a material point of unit mass in a field determined by a generalized Hénon–Heiles potential $U=A{q}_1^2+B{q}_2^2+C{q}_1^2{q}_2+D{q}_2^3$, with $(q_1,q_2)=$ standard Cartesian coordinates and $(A,B,C,D)\in {(0,\infty )}^2\times R^2$, is addressed for two limit situations: collision and escape. Using McGehee-type transformations, the corresponding collision and infinity boundary manifolds pasted on the phase space are determined. These are fictitious manifolds, but, due to the continuity with respect to initial data, their flow determines the near by orbit behaviour.The dynamics on the collision and infinity manifolds is fully described. The topology of the flow on the collision manifold is independent of the parameters. In the full phase space, while spiraling collision orbits are present, most of the orbits avoid collision. The topology of the flow on the infinity manifold changes as the ratio between $C$ and $D$ varies. More precisely, there are two symmetric pitchfork bifurcations along the line $2C?3D=0$, due to the reshaping of the potential along the bifurcation line. Besides rectilinear and spiraling orbits, the near-escape dynamics includes oscillatory orbits, for which angular momentum alternates sign.     

Non-Thermal Photon Emission from Shell-Type Supernova Remnants

We study the non-thermal photon emission from shell-type supernova remnants （SNRs） in the frame of a two-zone model. In this model, the sites of acceleration, escape and subsequent radiation of particles （both electron and proton） are divided into acceleration and escape zones, respectively. The particle distributions consist of two components, one is produced inside the acceleration zone, the other in the escape zone. We apply this model to two young and one old shell-type SNRs and show that the observed multi-waveband photon spectra for the three SNRs can be explained well in this model and high-energy γ-rays from these SNRs may have hadronic origins.     

Asymptotic analysis of the nonsteady micropolar fluid flow through a curved pipe

ABSTRACT

We consider the nonsteady flow of a micropolar fluid in a thin (or long) curved pipe via rigorous asymptotic analysis. Germano's reference system is employed to describe the pipe's geometry. After writing the governing equations in curvilinear coordinates, we construct the asymptotic expansion up to a second order. Obtained in the explicit form, the asymptotic approximation clearly demonstrates the effects of pipe's distortion, micropolarity and the time derivative. A detailed study of the boundary layers in space is provided as well as the construction of the divergence correction. Finally, a rigorous justification of the proposed effective model is given by proving the error estimates.     

Two interesting derivatives of 1-amino-1-hydrazino-2,2-dinitroethylene (AHDNE): synthesis and thermal properties

Journal of Thermal Analysis and Calorimetry - Two new interesting compounds, ethanedial-1,2-bis-(2-(1-amino-2,2-dinitroethenyl))hydrazone (EDNH) and 3-dinitromethyl-1,2,4-triazine (DNTA), were...     

Double dehydrogenation of carbocyclic β-dicarbonyl compounds:Koser's reagent can do what iodine(V) reagents can

Koser's reagent is found to be effective in the oxidative double dehydrogenation of various carbocyclic β-dicarbonyl compounds,which constitutes the first example on dehydrogenation reactivity of hypervalent iodine(Ⅲ) reagents for carbocyclic carbonyl compounds. DFT calculations reveal that the rate-determining step is the electrophilic addition of PhI+OH onto enolate of monodehydrogenated product.