Estimation of Basins of Attraction for Uncertain Systems with Affine and Lipschitz Dynamics

This paper is devoted to estimation and numerical approximation of basins of attraction for a class of uncertain systems. We consider systems described by a differential equation depending of a disturbance known by its bounds. By using viability theory tools, we derive basins of attraction lower and upper estimates. We present numerical simulation results of the viability kernel algorithm to basin of attraction approximation problems.     

Modeling And Performance Evaluation Of Branch And Value Prediction In Ilp Processors

Speculative execution is one of the key issues to boost the performance of future generation microprocessors. In this paper, we introduce a novel approach to evaluate the effects of branch and value prediction, which allow the processor to execute instructions beyond the limits of control and true data dependences. Until now, almost all the estimations of their performance potential under different scenarios have been obtained using trace-driven or execution-driven simulation. Occasionally, some simple deterministic models have been used. We employ an analytical model based on recently introduced Fluid Stochastic Petri Nets (FSPNs) in order to capture the dynamic behavior of an ILP processor with aggressive use of prediction techniques and speculative execution. Here we define the FSPN model, derive the state equations for the underlying stochastic process and present performance evaluation results to illustrate its usage in deriving measures of interest. Our implementation-independent stochastic modeling framework reveals considerable potential for further research in this area using numerical solution of systems of partial differential equations and/or discrete-event simulation of FSPN models.     

A method for observing the three-dimensional morphologies of inclusions in steel

A method for observing the three-dimensional morphologies of inclusions by deeply eroding a steel sample with a kind of organic solution composed of bromine water,acetone,and HC1 (volume ratio,45∶45∶10...     

短纤维与球状颗粒双相夹杂增强陶瓷基复合材料有效力学性能分析的广义Mori-Tanaka法

结合Eshelby夹杂理论和Mori-Tanaka方法推导陶瓷基体中含两种以上不同形状和不同力学性质的夹杂情况下,复合材料的有效力学性能计算的广义Mori-Tanaka解析计算式,分析颗粒与短纤维夹杂对复合材料有效力学性能的影响,并用三维均质化法检验所得解析式的可靠性。结果表明,解析模型与均质化法得到的结果非常吻合,不同形状的夹杂对有效力学性能的影响很大,短纤维增强相能够有效改善复合材料沿短纤维方向的纵向有效力学性能,对提高多相混合增强陶瓷基复合材料的刚度和强度起主要作用;球状颗粒增强相能有效改善复合材料的横向有效力学性能,并保持复合材料强度的稳定性,不同形状的夹杂能够综合改善陶瓷基复合材料的力学性能。     

NUMERICAL SIMULATION OF PROPAGATION AND BREAKING PROCESSES OF A FOCUSED WAVES GROUP

A two-dimensional numerical wave flume is developed to study the focused waves group propagation and the consequent breaking processes. The numerical model is based on the Reynolds-Averaged Navier-Stokes (RANS) equations, with the standard k-ε turbulence model to simulate the turbulence effects. To track the complicated and broken free-surface, the Volume Of Fluid (VOF) method is employed. The numerical model combines the "Partial Cell Treatment (PCT)" method with the "Locally Relative Stationary (LRS)" concept to treat the moving wave paddle so that various waves can be generated directly in a fixed Cartesian grid system. The theoretical results of the linear and nonlinear waves are used to validate the numerical wave flume firstly, and then a plunging breaking wave created by a focused waves group is simulated. The numerical results are compared to the experimental data and other simulation results, with very good agreements. The turbulence intensity, the flow field and the energy dissipation in the breaking processes are analyzed based on the numerical results. It is shown that the present numerical model is efficient and accurate for studying the waves group generation, the waves packet propagation, and the wave breaking processes.     

Existence and release of fluid inclusions in bornite and its associated quartz and calcite

The existence and release of fluid inclusions in bornite and its associated minerals, namely, quartz and calcite were investigated and confirmed. The structures, forms, and phases of these large quantities of fluid inclusions were also studied. A mass of fluid inclusions with various sizes, distributions, shapes, and phases exist in bornite and its associated minerals. Their sizes vary from a few micrometers to tens of micrometers, and the forms appear as negative crystals, or elongated, elliptical, and irregular. At room temperature, fluid inclusions were mainly characterized as gas-liquid two- phase. However, small amounts of fluid inclusions with pure gas phase and pure liquid single-phase were also observed in quartz and calcite. These fluid inclusions initially broke during the ore crushing and grinding process and then released into the flotation pulp in the flotation process. The quantitative analysis of fluid inclusions in the solution and the comparisons of mineral dissolution show that the amount of copper and iron released by fluid inclusions in the bornite sample is higher than the amount dissolved by the mineral; fluid inclusions in the associated gangue minerals, quartz, and calcite also make contribution.     

Precipitation and control of BN inclusions in 42CrMo steel and their effect on machinability

The precipitation and control of boron nitrogen （BN） inclusions in 42CrMo steel were investigated and their effect on machinability was analyzed. First, the precipitation regularity of BN in 42CrMo steel was studied by theoretical calculation. Then, the machinability of the steel was investigated through contrast cutting experiments, and the composition and cooling rate of the steel were controlled to analyze the variation laws of the size, distribution, and area ratio of BN inclusions. Finally, the results were combined with the machinability of the steel to analyze the relationship among them. It is found that the machinability of the steel is mainly influenced by the diameter and quantity of BN inclusions. Fine and dispersedly distributed BN inclusions are more beneficial for the improvement in machinability of 42CrMo steel than coarse and sparse BN inclusions.     

催化裂化柴油各馏分段碱性氮及总硫含量分布研究

对多家炼厂的催化裂化（FCC）柴油采用按体积切割馏分段的方式,对各个馏分段的碱性氮含量和总硫含量进行测试分析。结果表明,在FCC柴油中,总硫含量随着沸点的升高而升高,但碱性氮含量却随着沸点的升高而降低;以直馏柴油作对照实验,结果表明,在直馏柴油中,碱性氮和总硫含量都随沸点的升高而升高。在FCC柴油0％～60％（体积分数）的轻馏分段中集中了78．6％～86．9％的碱性氮,而在60％～100％（体积分数）的重馏分段中集中了49％～56％的硫化物。在FCC柴油中碱性氮主要集中在轻馏分,硫化物主要集中在重馏分。     

硫酸氢盐离子液体萃取氧化脱硫研究

合成了一系列烷基碳链长度不同的1-烷基-3-甲基咪唑硫酸氢盐离子液体,以质量分数为35％的H2O2为氧化剂,考察了萃取时间、剂油体积比、温度等不同条件对模拟油品的脱硫效果,确定了最佳脱硫实验条件;在最佳实验条件下,考察反应体系对FCC汽油、柴油的脱硫效果。结果表明,[C3mim]HSO4离子液体的脱硫效果最好。在V（[C3mim]HSO4）／V（H2O2）／V（模型油）-1：1：30,60℃的条件下反应90min,对模拟油品及实际油品均有较高的脱硫率,对模拟油品一次脱硫率为88．38％,对抚顺石化公司石油二厂的FCC柴油的一次脱硫率在80％以上,FCC汽油经一次脱硫后,硫的质量分数下降至10μg／g以下,显示了很高的工业应用前景。