Relation Between the Anderson Transition Zone and the Wave Vector in the Aubry Model

In a previous work of ours the numerical results have proved that there exists the Anderson transition zone in the Aubry model of one-dimensional incommensurate systems. In this paper, we further investigate the relation between the Anderson transition zone and the wave vector in this model. Our numerical results show that the Anderson transition zone is relative immediately to the wave vector, that is to say, the smaller the wave vector, the lower the value of the potential strength V in which the Anderson transition zone lies.     

Properties of the Interfacial Transition Zone in Model Concrete

The interfacial transition zone (ITZ) between aggregates and cement paste in cementitious materials is a crucial element in mechanical and transport systems. Computer simulation by the SPACE system is used to approach this problem in the present paper. For the particle-packing phenomenon in the fresh state of concrete, the SPACE system relies on a dynamic generation algorithm, reflecting the production conditions of concrete. Hence, structure of the model cement has been proven more realistic than can be achieved by random generator-based system.A natural phenomenon in the ITZ around aggregate particles is size segregation leading to different gradients in porosity, particle size and surface area. Size segregation implies the difference size fractions in the binder mixture to have peak values in their densities on different distances from the aggregate surface. Structural evolution of the ITZ is stereologically quantified with the help of composition and configuration parameters in the fresh and hardened states of concrete.The addition of mineral admixtures is a successful approach to improving the ITZ microstructure. Experiments demonstrated the blending efficiency to be higher for coarser grained Portland cement (PC), due to the positive effect exerted by gap grading, i.e. by having distinctly different size ranges of particles. This is confirmed by computer simulation of the ITZ microstructure in model concretes made with blended cements. In addition, it is very important in concrete production to achieve good workability conditions to ensure sufficient dispersion of the fine rice husk ash (RHA) particles and proper migration of them into the ITZ through the structure network of large cement particles.     

The Phase Transition in the Three-State Potts Model: An Analytical Analysis

Weinvestigate thephase transition of the three-state Potts model in an analytical approachthe generalized cumtilant expansion with the effective mean field Itypothesis. We find a first order phase transition in the three-dimensional three-state Pot ts model with ferromagnetic nearest neighbor (nn) coupling. For the model with antiferromagnetic next-to-nearest neighbor (nnn) coupling, pe find a first order transition when tlle relative strength of the nnncoupling γ is fixed to -0.2. The critical values given by this method are also in agreement with the recent high statistics Monte Carlo results.     

Phase Transitions of an Epidemic Spreading Model in Small-World Networks

We propose a modified susceptible-infected-refractory-susceptible (SIRS) model to investigate the global oscillations of the epidemic spreading inWatts-Strogatz (WS) small-world networks. It is found that when an individual immunity does not change or decays slowly in an immune period, the system can exhibit complex transition from an infecting stationary state to a large amplitude sustained oscillation or an absorbing state with no infection. When the immunity decays rapidly in the immune period, the transition to the global oscillation disappears and there is no oscillation. Furthermore, based on thespatio-temporal evolution patterns and the phase diagram, it is disclosed that a long immunity period takes an important role in the emergence of the global oscillation in small-world networks.     

Scaling Analysis for the Adsorption Transition in a Watermelon Network of n Directed Non-Intersecting Walks

The partition function for the problem of n directed non-intersecting walks interacting via contact potentials with a wall parallel to the direction of the walks has previously been calculated as an n×n determinant. Here, we describe how to analyse the scaling behaviour of this problem using alternative representations of the solution. In doing so we derive the asymptotics of the partition function of a watermelon network of n such walks for all temperatures, and so calculate the associated network exponents in the three regimes: desorbed, adsorbed, and at the adsorption transition. Furthermore, we derive the full scaling function around the adsorption transition for all n. At the adsorption transition we also derive a simple product form for the partition function. These results have, in part, been derived using recurrence relations satisfied by the original determinantal solution.     

The Interfacial Transition Zone (ITZ) Between Cement Paste and Aggregate in Concrete

This paper describes the so called interfacial transition zone—ITZ—in concrete. This is the region of the cement paste around the aggregate particles, which is perturbed by the presence of the aggregate. Its origin lies in the packing of the cement grains against the much larger aggregate, which leads to a local increase in porosity and predominance of smaller cement particles in this region. The ITZ is region of gradual transition and is highly heterogeneous, nevertheless the average microstructural features may be measured by analysis of a large numbers of backscattered electron images of polished concrete samples. Such measurements show that the higher porosity present initially is significantly diminished by the migration of ions during hydration.     

Analysis of the influence of backscattered optical power over bidirectional PON links

Our aim is to describe the behavior of non-linear scattering effects that arise in standard single mode fiber (SMF), specifically scattering effects that propagate optical power in the reverse direction of the source signal such as Rayleigh Scattering (RS) and Brillouin Scattering (BS). For this purpose, the effects of backscattering phenomena over a bidirectional data transmission in a passive optical network (PON) scheme have been assessed. The impact of these high optical power components over reception at the optical line terminal (OLT) side has been determined when both links use the same wavelength. Bit Error Rate (BER) measurements have been performed with different transmission rates, using several techniques to mitigate the influence of backscattering over the received signal and considering cases with filtered and unfiltered BS.     

Transition to Chaos in the Floating Half Zone Convection

The transition process from steady convection to chaos is experimentally studied in thermocapillary convections of floating half zone. The onset of temperature oscillations in the liquid bridge of floating half zone and further transitions of the temporal convective behaviour are detected by measuring the temperature in the liquid bridge. The fast Fourier transform reveals the frequency and amplitude characteristics of the flow transition. The experimental results indicate the existence of a sequence of period-doubling bifurcations that culminate in chaos. The measured Feigenbaum numbers are δ2 =4.69 and δ4 = 4.6, which are comparable with the theoretical asymptotic value δ=4.669.     

Statistical Analysis of the Effect of Mineral Admixtures on the Strength of the Interfacial Transition Zone

Microscopic evidence indicates that the thickness of the interfacial transition zone (ITZ) between the aggregate and the cement paste is modified when mineral admixtures partially replace portland cement. Unfortunately, there is limited information on the significance of these microscopic modifications to the mechanical properties of the ITZ. This research reports experimental results on the shear and tensile strength of the ITZ as affected by the addition of the following mineral admixtures: silica fume, fly ash, and natural pozzolan. Statistical analysis was used to identify the significant parameters affecting the tensile and shear strength of the ITZ. Experimental results indicate that not only does the incorporation of silica fume and fly ash increase the strength of the ITZ, these mineral admixtures have a greater influence on the strength increase of the ITZ than in the strength increase of the cement paste.     

Finite-Size Scaling Analysis of a Three-Dimensional Blume--Capel Model in the Presence of External Magnetic Field

The Blume-Capel model in the presence of external magnetic field H has been simulated using a cellular automaton algorithm improved from the Creutz cellular automaton in three-dimension lattice. The field critical exponent 5 is estimated using the power law relations and the finite size scaling functions for the magnetization and the susceptibility in the range -0.1≤ h = H/J ≤0. The estimated value of the field critical exponent 5 is in good agreement with the universal value （δ = 5） in three dimensions. The simulations are carried out on a simple cubic lattice under periodic boundary conditions.     

The Finite-Size Scaling Functions of the Four-Dimensional Ising Model

A finite-size scaling function of the Privman–Fisher form is proposed for the singular part of the free-energy density of the four-dimensional Ising model. It leads to the finite-size scaling relations available and to the prediction of new ones.     

Ballistic Deposition模型孔洞生长标度行为的数值模拟

为研究表面界面粗化生长中孔洞的标度行为,在对Ballistic Deposition(BD)模型进行数值模拟的基础上,对模型中孔洞的模拟生长情况进行统计和分析.结果表明,BD模型中孔洞数目随模型生长时间的变化从初始阶段的高于线性而渐趋近于线性,并对该规律进行理论分析.     

惰性气体黏度的剩余熵标度模型

黏度是能源、动力、化工等系统设计分析中常用的重要物性参数.本文探讨了5种惰性气体(He、Ne、Ar、Kr、Xe)气相和超临界黏度的计算,以实际气体与同温度稀薄气体的黏度之比作为无量纲对比黏度,发现5种惰性气体的无量纲对比黏度与剩余熵之间满足同一单值函数关系,据此建立了惰性气体的气相和超临界黏度模型,其中稀薄气体黏度关联...     

不同傅里叶近红外仪器间(积分球漫反射测量)的模型传递及误差分析

模型传递是近红外光谱分析技术中一个关键的共性基础技术问题,通过在同一工作原理的两台仪器之间寻求可行的数学方法, 使得在一台仪器上建立的模型能够应用于另外一台仪器样品光谱响应的预测,对近红外技术的实际应用具有重要意义。以150份烤烟作为试验样品,以两台布鲁克公司MPA近红外光谱仪,一台热电公司Antaris近红外光谱仪作为研究对象,通过积分球漫反射检测技术获得光谱数据。采用一阶导数(first-order derivative,1st Der)和标准正态变量变换(standard normal variate, SNV)对光谱数据进行处理分析,计算不同仪器间光谱的残差值、残差一阶矩、残差信号概率密度和最大信噪比等参数,并采用偏最小二乘法(partial least squares, PLS)建立烤烟总糖含量数学模型,检验模型传递效果。结果表明,一阶导数具有降低残差一阶矩,将仪器偏差信号转换为标准高斯分布的优点,但同时会降低信噪比。标准正态变量变换同样可以降低一阶矩,同时可大幅度提高信噪比,但无法将仪器偏差信号转换为标准高斯分布,需要进一步的信号处理。一阶导数与SNV相结合可保留两种方法的优点,同时在一定程度上弥补每种方法单独处理的缺点,是一种可以消除以积分球漫反射作为光谱测量方式的因仪器厂家或型号不同、使用年限不同等原因所产生的噪声的处理方法,可实现傅里叶型近红外光谱仪之间的模型传递效果的明显改善。     

Finite Size Scaling of the Dynamical Free-Energy in a Kinetically Constrained Model

We determine the finite size corrections to the large deviation function of the activity in a kinetically constrained model (the Fredrickson-Andersen model in one dimension), in the regime of dynamical phase coexistence. Numerical results agree with an effective model where the boundary between active and inactive regions is described by a Brownian interface.     

Determination and Analysis of the Thermodynamic Regimes of Xenon Plasmas

Xenon is a common element employed, for example, as impurity in magnetically confined plasmas or the medium in which radiative shocks propagate in laboratory astrophysics. In both situations, it is required the knowledge of plasma parameters such as the average ionization, the charge state distribution, the atomic level populations and the radiative properties. In most cases, the plasmas are under non‐local thermodynamic equilibrium (NLTE) conditions and these quantities should be determined by means of the so‐called collisionalradiative models. For a high Z element like xenon this is a complex task and entails a high computational cost since it is necessary to solve a very large set of rate equations. In this work are characterized the thermodynamic regimes of xenon plasmas as a function of the matter density and temperature. This fact will allow us to establish in which regions of density and temperature the assumption of local thermodynamic equilibrium (LTE) is accurate and also in which regions it can be retained to estimate some plasma parameters but not others. Moreover, it is also provided information about the average ionization in a wide range of plasma conditions which covers both LTE and NLTE regimes which is valuable information in order to optimize subsequent calculations. Finally, it is also performed an analysis of the differences of NLTE and LTE simulations on several relevant plasma parameters. With this purpose, a comparison is made between the results of the calculation using detailed NLTE modeling with simulations that use the same energy level structure, but atomic populations that are forced into LTE (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Pulsational Instability of Non-Isothermal Magnetized Accretion Disk with Self-Gravity in the Transition Zone

By analyzing the fifth-order dispersion relation, the influence of coupled magnetic field and self-gravity on the pulsational instability of gas pressure dominated accretion disk is investigated. Our main results are that the viscous modes become more stable with the increase of self-gravity, magnetized field and viscosity, while they enhance the instabilities of acoustic modes. The effect of self-gravity to the instability is much greater than that of magnetic field in transition zone of the accretion disk. Especially, the self-gravity affects the thermal-modes and acoustic modes strongly. Finally, we discuss our results.     

An Analytical Model for the Coupling Between the Array Waveguides in AWGs and Star Couplers

The purpose of this paper is to present an accurate analytical solution for the coupling between the array waveguides in arrayed waveguide grating (AWG) devices and star couplers. The results of this analysis will be useful for developing numerical models of AWGs and star couplers, as well as other optical waveguide components containing arrays of coupled waveguides.     

Dynamical Phase Transition in a Neural Network Model with Noise: An Exact Solution

The dynamical organization in the presence of noise of a Boolean neural network with random connections is analyzed. For low levels of noise, the system reaches a stationary state in which the majority of its elements acquire the same value. It is shown that, under very general conditions, there exists a critical value _c of the noise, below which the network remains organized and above which it behaves randomly. The existence and nature of the phase transition are computed analytically, showing that the critical exponent is 1/2. The dependence of _c on the parameters of the network is obtained. These results are then compared with two numerical realizations of the network.     

Features of the Elastic Properties of HTSC Ceramics in the Transition Zone to the Superconducting Phase

Acoustical Physics - The article presents the results of studies of the elastic properties of the YBa2Cu3O(7 –x) high-temperature superconducting ceramic in the vicinity of the phase...