高温气冷堆冷却剂杂质对高温合金材料高温性能影响的研究模型分析

高温气冷堆一回路冷却剂中含有的少量CO、H_2、H_2O、CH_4等杂质,这些杂质对高温堆蒸汽发生器用高温合金的高温性能有重要影响。国外在超高温运行工况下冷却剂杂质对高温合金材料性能的影响方面开展了大量研究,由于研究过程中对试验氦气中痕量的杂质含量控制十分困难,致使相关的研究成果分布比较分散,需要对相关的研究模型进行归纳和分析。高温镍铬合金中的铬是被氧化的主要合金元素,而保护性Cr_2O_3层的形成是合金是否被腐蚀的主要决定因素;铬的稳定相图模型和气体组成三元相图模型是两种被广泛应用的理论模型。本文对铬的这两种理论模型研究方法及其应用情况进行比较和分析。

掺铥锗酸盐激光玻璃光谱特性定量计算与预测

掺稀土激光玻璃是光纤激光器的核心工作介质,如何定量计算预测激光玻璃的光学光谱特性是加快高性能激光玻璃研发的挑战之一。本文以掺铥(Tm^(3+))二元锗酸盐激光玻璃为例,将相图中的“一致熔融化合物”视为玻璃的组成/结构“基元”,基于掺Tm^(3+)基元玻璃的物理和光谱性质的实验值利用杠杆规则计算预测了锗酸盐激光玻璃相应的性质,如密度、折射率、有效线宽、吸收/发射截面、辐射寿命、增益带宽等。结果表明,物理性质和光谱特性的预测值与实验值吻合度较高,预测误差绝对值分别小于4.61%和9.66%。此外,该方法能够准确预测掺Tm^(3+)锗酸盐玻璃的物理性质和光谱特性随组分的变化趋势,包括线性规律和“锗反常”现象,有助于解析激光玻璃组成-结构-性质的内在关联。本研究有望为激光玻璃的性质预测和成分设计提供指导。

玻璃的相图结构模型

提出了玻璃的相图结构模型,并对之进行了讨论.在不同玻璃系统中用实验数据证实了所提出的玻璃相图结构模型的正确性.

Phase Structure in a Quark Mass Density-and-Temperature-Dependent Model

The phase diagram of bulk quark matter in equilibrium with a finite hadronic gas is studied. Different from previous investigations, we treat the quark phase with the quark mass density-and-temperature-dependent model to take the strong quark interaction into account, while the hadron phase is treated by hard core repulsion factor. It is found that the phase diagram in this model is, in several aspects, different from those in the conventional MIT bag model, especially at high temperature. The new phase diagram also has strong effects on the mass-radius relation of compact hybrid stars.

Phase Diagram for Ashkin-Teller Model on Bethe Lattice

Using- the recursion method, we study the phase transitions of theAshkin-Teller model on the Bethe lattice, restricting ourselves to the case of ferromagneticinteractions. The isotropic Ashkin-Teller model and the anisotropic one are respectivelyinvestigated, and exact expressions for the free energy and the magnetization are obtained. It canbe found that each of the three varieties of phase diagrams, for the anisotropic Ashkin-Tellermodel, consists of four phases, i.e., the fully disordered paramagnetic phase Para, the fullyordered ferromagnetic phase Ferro, and two partially ordered ferromagnetic phases 【 σ 】 and 【 σs】, while the phase diagram, for the isotropic Ashkin-Teller model, contains three phases, i.e., thefully disordered paramagnetic phase Para, the fully ordered ferromagnetic phase Baxter Phase, andthe partially ordered ferromagnetic phase 【 σs 】.

Superlattice Patterns in Coupled Turing Systems

In this paper, superlattice patterns have been investigated by using a two linearly coupled Brusselator model. It is found that superlattice patterns can only be induced in the sub-system with the short wavelength. Three different coupling methods have been used in order to investigate the mode interaction between the two Turing modes. It is proved in the simulations that interaction between activators in the two sub-systems leads to spontaneous formation of black eye pattern and/or white eye patterns while interaction between inhibitors leads to spontaneous formation of super-hexagonal pattern. It is also demonstrated that the same symmetries of the two modes and suitable wavelength ratio of the two modes should also be satisfied to form superlattice patterns.

The Collins Model and the Eutectic—Type and the Peritectic—Type Phase Diagrams

From the Gibbs free energy and the equations of two-phase equilibrium curves of the two-dimensionalbinary system which has the Lennard-Jones potential, using the Collins model, the eutectic-type phase diagram and theperitectic-type phase diagram of the binary system are obtained, whose results are quite similar to the behavior of thethree-dimensional (3D) substances.

Collins Model and Phase Diagram of 2D Ternary System

The Collins model is introduced into the two-dimensional (2D) alternative ternary system having the Lennard-Jones (L-J) potential. The Gibbs free energy of this ternary system is calculated, and according to thermodynamic theory, a group of equations that determine the solid-liquid diagram of ternary system are derived, someisothermal sectional diagrams of the 2D ternary system are obtained. The results are quite similar to the behavior ofthree-dimensional substances.

Unsupervised Change Detection in Multitemporal SAR Images Using MRF Models

An unsupervised change-detection method that considers the spatial contextual information in a log-ratio difference image generated from multitemporal SAR images is proposed. A Markov random filed (MRF) model is particularly employed to exploit statistical spatial correlation of intensity levels among neighboring pixels. Under the assumption of the independency of pixels and mixed Gaussian distribution in the log-ratio difference image, a stochastic and iterative EM-MPM change-detection algorithm based on an MRF model is developed. The EM-MPM algorithm is based on a maximiser of posterior marginals (MPM) algorithm for image segmentation and an expectation-maximum (EM) algorithm for parameter estimation in a completely automatic way. The experiment results obtained on multitemporal ERS-2 SAR images show the effectiveness of the proposed method.

Study and application of monitoring plane displacement of a similarity model based on time-series images

In order to compensate for the deficiency of present methods of monitoring plane displacement in similarity model tests,such as inadequate real-time monitoring and more manual intervention,an effective monitoring method was proposed in this study,and the major steps of the monitoring method include:firstly,time-series images of the similarity model in the test were obtained by a camera,and secondly,measuring points marked as artificial targets were automatically tracked and recognized from time-series images.Finally,the real-time plane displacement field was calculated by the fixed magnification between objects and images under the specific conditions.And then the application device of the method was designed and tested.At the same time,a sub-pixel location method and a distortion error model were used to improve the measuring accuracy.The results indicate that this method may record the entire test,especially the detailed non-uniform deformation and sudden deformation.Compared with traditional methods this method has a number of advantages,such as greater measurement accuracy and reliability,less manual intervention,higher automation,strong practical properties,much more measurement information and so on.

Thermodynamic modeling of ZrO_(2)−CaO−TiO_(2)system

The phase diagram of ZrO_(2)−CaO−TiO_(2)system was essential for the development of photocatalytic materials and refractory materials.In this work,the ZrO_(2)−CaO−TiO_(2)system was accessed by using the CALPHAD method.The substitutional solution models were used to describe liquid and solid solution phases,the sub-lattice models were used to describe ternary compounds,and then the thermodynamic parameters were obtained by the least square method combined with literature experiment results.The acquired thermodynamic parameters were used to calculate the isothermal sections of the ZrO_(2)−CaO−TiO_(2)system at 1473 and 1673 K.There existed a good agreement between experimental and predicted phase relationships,the experimental points which were inconsistent with calculated results may be attributed to experimental errors and the sluggish kinetics of cations for ZrO_(2)-based materials.In order to further verify the validity of the database,the thermodynamic parameters were also used to simulate the thermodynamic properties(specific heat capacity,enthalpy,and entropy)of CaZrTi_(2)O_(7) within 5%errors.Good consistency demonstrated that the present thermodynamic database was self-consistent and credible.

System Structure and Calibration Models of Intelligent Photogrammetron

This paper describes the structure, geometric model and geometric calibrationof Photogrammetron Ⅰ - the first type of photogrammetron which is designed to be a coherent stereophotogrammetric system in which two cameras are mounted on a physical base but driven by anintelligent agent architecture. The system calibration is divided into two parts: the in-labcalibration determines the fixed parameters in advance of system operation, and the in-situcalibration keeps tracking the free parameters in real-time during the system operation. In a videosurveillance set-up, prepared control points are tracked in stereo image sequences, so that the freeparameters of the system can be continuously updated through iterative bundle adjustment and Kalmanfiltering.

Phase Diagram of XY Model with Nematic Coupling on the Simple Cubic Lattice

Using cluster Monte Carlo method, we numerically investigate the coupling on the simple cubic lattice. We determine critical lines belong to the criticality in the XY model with nematic three-dimensional XY universality class in variable of θ （2θ） between the XY-ferromagnetic （nematic） and disordered states. Fhrthermore, the phase transition between the XY-ferromagnetic and the nematie states is found to be in the three-dimensional Ising universality class. The critical points are determined from the intersections of Binder ratios for various system sizes. With two sets of critical points obtained, we finally construct the phase diagram on the A-J plane.

Using texture synthesis in fractal pattern design

Traditional fractal pattern design has some disadvantages such as inability to effectively reflect the characteristics of real scenery and texture. We propose a novel pattern design technique combining fractal geometry and image texture synthesis to solve these problems. We have improved Wei and Levoy (2000)’s texture synthesis algorithm by first using two-dimensional autocorrelation function to analyze the structure and distribution of textures, and then determining the size of L neighborhood. Several special fractal sets were adopted and HSL (Hue, Saturation, and Light) color space was chosen. The fractal structure was used to manipulate the texture synthesis in HSL color space where the pattern’s color can be adjusted conveniently. Experiments showed that patterns with different styles and different color characteristics can be more efficiently generated using the new technique.

用相图原理研究玻璃结构和性质(Ⅲ) 核磁共振谱研究钠硼钒、钾硼磷、钾硼铝和钠硼镁玻璃结构

本文运用相图模型方法,通过电子计算机计算了Na_2O-B_2O_3-V_2O_5,K_2O-B_2O_3-P_2O_5,K_2O-B_2O_3-Al_2O_3和Na_2O-B_2O_3-MgO三元系统玻璃的NMR数据,比较了实验值和计算得出的硼四配位分数(N4),得到了满意的结果。

基于CFD-DEM耦合数值模拟的垂直管道气力输送流型特性研究

针对垂直管气力输送过程,采用计算流体力学与离散元(computational fluid dynamics and discrete element method,CFD-DEM)耦合数值模拟的方法,从截面颗粒体积分数、管道内流型演变及单位管长压降等3个方面对不同表观气速下垂直管气力输送颗粒运动特性展开研究。研究结果表明:随着表观气速的增加,管内流型依次呈现高浓度环核流、中浓度环核流、低浓度环核流及悬浮流;截面颗粒体积分数随着管内流型的转变逐渐减小;得到输送压降、输送流型随表观气速变化的相图模型及压降最低点的速度为8 m·s^(-1)。

Microcanonical Phase Diagram of the BEG and Ising Models

The density of states of long-range Blume-Emery-Criffiths （BEG） and short-range lsing models are obtained by using Wang-Landau sampling with adaptive windows in energy and magnetization space. With accurate density of states, we are able to calculate the mierocanonical specific heat of fixed magnetization introduced by Kastner et al. in the regions of positive and negative temperature. The microcanonical phase diagram of the Ising model shows a continuous phase transition at a negative temperature in energy and magnetization plane. However the phase diagram of the long-range model constructed by peaks of the microeanonieal specific heat looks obviously different from the Ising chart.

Effects of Bond Alternation on the Ground-State Phase Diagram of One-Dimensional XXZ Model

The ground-state properties and quantum phase transitions （ QPTs） of the one-dimensional bond-Mternative XXZ model are investigated by the infinite time-evolving block decimation （iTEBD） method. The bond-alternative effects on its ground-state phase diagram are discussed in detail. Once the bond alternation is taken into account, the antiferromagnetic phase （△ 〉 1） will be destroyed at a given critical point and change into a disordered phase without nonlocal string order. The QPT is shown to be second-order, and the whole phase diagram is provided. For the ferromagnetic phase region （△ 〈 --1）, the critical point re always equals 1 （independent of △）, and the QPT for this case is shown to be first-order. The dimerized Heisenberg model is also discussed, and two disordered phases can be distinguished by with or without nonlocal string orders. Both the bipartite entanglement and the fidelity per site, as two kinds of model-independent measures, are capable of describing all the QPTs in such a quantum model.

Axial Breakthrough in Ancient Greece. New Considerations： Plato, Confucius, and the Buddha

Here I will examine the resemblances and similarities between Plato and two other personages, Confucius and the Buddha, who were his near-contempo- raries, and who enabled a breakthrough. The Platonic break with the world of bodies and the sphere of belief, in favor of a level of intelligible realities, the models of the sensible realities explained by mathematics and moved by the soul, explains the specificity of the Western world, in the field of science, politics, ethics, and even religion.

Modeling of information images dynamics through the communicative field method

This work presents a formalized description of information and communicative interac- tions of individuals on the basis of the communicative field （CF） method. It also contains explication of the possibility to create model of information and communication inter- actions, which is able to illustrate both interactions between two and more individuals. Methods and approaches which are suggested in this paper can correctly simulate the processes of distortion and generation of information images （IIs） with information and communication social interaction. Expansion and addition of IIs theory in terms of the transmission of information between individuals allows us to speak about the space of IIs. This space helps to explain a number of characteristic phenomena of human thinking.