Characteristics of mixed traffic flow with non-motorized vehicles and motorized vehicles at an unsignalized intersection

In this paper, a new two-dimensional car-following model is proposed to depict the features of mixed traffic flow consisting of motorized vehicles (m-vehicle) and non-motorized vehicles (nm-vehicle), based on the two-dimensional optimal velocity (OV) model by Nakayama et al. [A. Nakayama, K. Hasebe, Y. Sugiyama, Phys. Rev. E 71 (2005) 036121]. In the proposed model, velocity difference terms are introduced, which are regarded as important factors for traffic behavior. Numerical simulations are carried out to investigate the interaction between left-turning nm-vehicle flow and straight-going m-vehicle flow at a typical unsignalized interaction. The results show that the straight-going m-vehicle flow just next to nm-lane is disturbed more seriously than others. In addition, a well-known phenomenon in reality is observed that groups of m-vehicles and nm-vehicles pass through the intersection alternately.     

基于脏脸博弈模型的人车路口穿越行为研究

行人与车辆在穿越无信号路口时的行为冲突尤其具有危险性, 行人和机动车不仅具有运动特征, 更具有行为特征, 因此需要从社会学层面对人车路口穿越问题进行建模. 通过对无信号路口处人车干扰机理的深入剖析, 提出基于脏脸博弈模型研究人车“理性人”的行为特征以及交互行为背后的微观机理, 分析了人车穿越路口时共同知识的形成过程、人车双方优势策略的产生机理和人车脏脸博弈的动力学过程. 理论推导了人、车收益的数学期望和发生人车冲突的概率. 分析结果表明: 行人穿越的理论时间和机动车穿越的理论时间越接近, 人车越容易发生冲突. 同时, 进一步分析了不同车型、不同行人等待时间和个体认知能力异质性对人车冲突概率的影响.     

低速十字路口交通流模型相图

研究由两个单车道构成低速十字路口交通流模型.模型中两车道上的车辆更新遵循无交通灯管制下的并行规则.依据构建相图的原则并采用局部占有概率方法,建立相图,给出相图中的各部分区域的流量表达式.两车道均采用周期边界条件和确定性FI模型进行数值模拟,模拟结果与理论分析精确一致.模型中两条车道的行车规则更接近实际道路交通,该结果为交通管理提供一定的指导作用.     

Study of traffic flow at an unsignalized T-shaped intersection by cellular automata model

In this paper, the traffic flow at an unsignalized T-shaped intersection in which there are three input directions of vehicles and two right-turnings and one left-turning has been investigated by using the cellular automata traffic model. The interactions between vehicles on different lanes and effects of traffic flow states of different roads on capacity of T-shaped intersection system are analyzed. The phase transition characteristics of traffic states on different lanes are studied. The research indicates that the model can be applied to the real traffic analysis and traffic forecast.     

Phase diagrams for the triangular Ising lattice with re-entrant ferromagnetism

We present the phase diagrams in a 2D spin 1/2 Ising model for the triangular lattice. Using the finitecluster approximation and renormalization technique we studied a nearest-neighbour random interactions. Ferromagnetic exchange interactionsJ are considered with concentrationp and exchange interactions J (||1) with concentration (1-p). The phase diagrams were obtained for this model. They show re-entrant behaviour in certain ranges of the concentrationp and different .     

Phase diagrams properties of the mixed traffic flow on a crossroad

Based on the Ishibashi and Fukui crossroad traffic flow model [Y. Ishibashi and M. Fukui. J. Phys. Soc. Japan. 70 (2001) 2793], mixed traffic flow (i.e., the fast and slow vehicles with different maximum velocities are mixed) is investigated in this work. According to the numerical simulation results and the principle for constructing the phase diagram, phase diagrams for mixed traffic flow are constructed. It is noted that the topology of these phase diagrams is similar to that of phase diagrams for homogeneous vehicles (which refers to slow vehicles only). From the phase diagrams, it is evident that mixed traffic flow is influenced by the mixing rate f (fraction of slow and fast vehicles) in regions II and V, but not in other regions. Although a mixture of fast and slow vehicles is introduced in the crossroad traffic flow model, the separation between phases in the phase diagrams remains linear. For a given q (the vehicle density on the northbound road), one flow plateau appears in regions IIx or IVy, while two maximum flow plateaus appear in region V in each of the phase diagrams. The maximum flow values in region V reflect the maximum traffic capacity for the traffic system as defined in this work. Since mixed traffic flow is a common phenomenon in real traffic, this work may offer help in real traffic simulations and traffic management.     

Phase diagrams of Ising fluids with Yukawa-Lennard-Jones interactions from an integral equation approach

An integral equation approach is developed to investigate phase coexistence properties of Ising spin fluids with Yukawa ferromagnetic and Lennard-Jones nonmagnetic interactions in the presence of an external field. The calculations are carried out on the basis of the Duh and Henderson closure with a specific Duh-like partitioning of the total potential. The coupled set of the Ornstein-Zernike equation, the closure relation and the external field constraint are solved using an efficient numerical algorithm. The phase diagrams are evaluated in a wide range of varying the external field and the ratio of strengths of Yukawa to Lennard-Jones interactions. Different types of the phase diagram topology as well as various external field dependencies of critical temperatures and densities are identified. The complexity with respect to simple Lennard-Jones fluids is explained by coupling between spatial and spin degrees of freedom in the system. A comparison of the obtained theoretical results with simulation data is made and a good agreement is observed.     

Phase diagrams of transition metals and the pseudopotential method

Phase stability boundaries for transition metals are derived from the condition of electron spectrum degeneration with respect to an external field.     

Phase diagrams for the precession states of the nanoparticle magnetization in a rotating magnetic field

Using the analytical and numerical solutions of the Landau–Lifshitz equation, we calculate the phase diagrams for the precession states of the nanoparticle magnetization in a rotating magnetic field. We show that there are three different scenarios for the magnetization switching. The bias magnetic field applied antiparallel to the nanoparticle magnetization strongly decreases the switching amplitudes and frequencies of the rotating field.     

Phase diagrams of Heusler alloys with inversion of the exchange interaction

The phase diagrams of magnetically ordered Heusler alloys with the inversion of the exchange interaction have been studied using the phenomenological Landau theory of phase transitions. It has been shown that the shape of the phase diagrams in these alloys depends on the magnitudes and signs of the phenomenological parameters in the Landau functional. At certain magnitudes and signs of the parameters of the Landau functional, the phase diagrams have thermodynamic paths that allow one to explain the experimentally observed sequences of the phase transitions in the Heusler alloys.     

Phase diagrams of noisy traffic states in the presence of a bottleneck

The traffic states are investigated for the noisy traffic flow in the presence of a bottleneck under the open boundary condition. The phase diagrams of the different kinds of congested traffic are presented for different values of sensitivity (the inverse of delay time). It is shown that the five different types of traffic states appear below the critical point: the free traffic with a pinned localized cluster, the weak standing shock, the moving localized cluster, the oscillatory congested traffic, and the strong standing shock. Above the critical point, the moving localized cluster and oscillatory congested traffic do not occur. Also, in the traffic flow without noise, the moving localized cluster and oscillatory congested traffic do not appear.     

Applicability of the approximation of equivalent photons for interference of diagrams of different orders

A study is made of the influence of the Coulomb field of a nucleus on a process that also occurs in the absence of interaction with the nucleus. It is shown that the approximation of equivalent photons applies to the interference between the diagram without interaction with the nucleus and the diagram of two-photon exchange with the nucleus, which contributes to the cross section of the process to the same order in the fine structure constant as the square of the diagram of single-photon exchange. As an example, the method of equivalent photons is used to calculate the cross section of the decay π → μ +ν on a nucleus.     

Phase diagrams of the CoMnO system in air

A retrospective critical analysis of phase diagrams of the CoMnO system in air has been made. A high-temperature phase equilibrium of the CoMnO system in air and phase diagrams of this system under different cooling conditions (quenching in water, quenching in air, cooling at rate of 25°K h^?1) have been constructed. A comparative analysis of these diagrams shows that whatever the cooling rate, cooling does not preserve the high-temperature state of the system and is accompanied (depending on cooling conditions, temperature and Co/Mn ratio) by one or more of the following phenomena: (1) oxidation of the Co_NMn_1?NO solution to spinel-type solid solutions (2) merging of a cubic and tetragonal spinel phase and formation of a homogeneous tetragonally distorted spinel (3) tetragonal distortion of the spinel lattice (4) decomposition of the cubic spinel into a cubic and tetragonal spinel. (5) decomposition of the cubic spinel into a cubic, tetragonal and slightly distorted tetragonal spinel. Therefore, the form of the phase diagram of the CoMnO system in air is entirely determined by the method of cooling.     

Exact phase diagrams for an Ising model on a two-layer Bethe lattice

Using an iteration technique, we obtain exact expressions for the free energy and the magnetization of an Ising model on a two-layer Bethe lattice with intralayer coupling constants J1 and J2 for the first and the second layer, respectively, and interlayer coupling constant J3 between the two layers; the Ising spins also couple with external magnetic fields, which are different in the two layers. We obtain exact phase diagrams for the system and find that when /J3/-->0, DeltaT(c) identical with[T(c)(J3)-T(c)(0)]/T(c)(0) approximately [J3]/J(1)/(1/psi), where T(c)(J3) is the phase-transition temperature for the system with interlayer coupling constant J3 and the shift exponent psi is 1 for J(1)=J(2) and is 0.5 for J1 not equal to J2. Such results are consistent with predictions of a scaling theory. We also derive equations for DeltaT(c) when /J3/ approaches infinity.     

Phase diagrams,electronic and magnetic properties of the quaternary Heusler alloy NbRhCrAl

In this paper, we are studying the quaternary Heusler alloy NbRhCrAl, using the full potential linearized augmented plane wave and the generalized gradient approximation of the exchange and correlation potential methods. For this purpose, we established the electronic and magnetic properties of this quaternary Heusler alloy. We investigated the density of states (DOS) and the band structure of this Heusler compound.This material contains three magnetic atoms: Nb, Rh and Cr modeled by the spin moments S = 1, P = 5/2 and Q = 3/2, respectively. In a first step, we elaborated the ground state phase diagrams in different physical parameter planes to explore the existing stable configurations. On the other hand, we used the MONTE CARLO simulations (MCS) to investigate the thermal behavior of the magnetizations of this system. Also, we have investigated the effect of varying the crystal field and the external magnetic field on the total magnetizations. To complete this study, we illustrated and discussed the hysteresis loops as a function of the external magnetic field, when fixing the values of the studied physical parameters.     

Phase diagrams of the transverse Ising antiferromagnet in the presence of the longitudinal magnetic field

In this paper we study the critical behavior of the two-dimensional antiferromagnetic Ising model in both uniform longitudinal (H$H$) and transverse (Ω$\Omega$) magnetic fields. Using the effective-field theory (EFT) with correlation in single site clusters we calculate the phase diagrams in the H−T$H-T$ and Ω−T$\Omega -T$ planes for the square lattice. We have only found second order phase transitions for all values of fields and reentrant behavior was not observed.     

Numerical simulation on partial coalescence of a droplet with different impact velocities

Partial coalescence is a complicated flow phenomenon. In the present study, the coalescence process is simulated with the volume of fluid(VOF) method. The numerical results reveal that a downward high-velocity region plays a significant role in partial coalescence. The high-velocity region pulls the droplet downward continuously which is an important factor for the droplet turning into a prolate shape and the final pinch-off. The shift from partial coalescence to full coalescence is explained based on the droplet shape before the pinch-off. With the droplet impact velocity increasing, the droplet shape will get close to a sphere before the pinch-off. When the shape gets close enough to a sphere, the partial coalescence shifts to full coalescence. The effect of film thickness on the coalescence process is also investigated. With large film thickness,partial coalescence happens, while with small film thickness, full coalescence happens. In addition, the results indicate that the critical droplet impact velocity increases with the increase of surface tension coefficient but decreases with the increase of viscosity and initial droplet diameter. And there is a maximum critical Weber number with the increase of surface tension coefficient and initial droplet diameter.