High‐order finite elements applied to the discrete Boltzmann equation

A discontinuous Galerkin approach for solving the discrete Boltzmann equation is presented, allowing to compute approximate solutions for fluid flow problems. Based on a two‐dimensional high‐order finite element and an explicit Euler time stepping scheme, the D2Q9 model is discretized and the results are compared to the exact solution of the Navier–Stokes equation. Four numerical examples are considered, including stationary and instationary problems with curved boundaries. It is demonstrated that the proposed method allows to obtain the desired, highly efficient exponential convergence. Copyright © 2006 John Wiley & Sons, Ltd.     

我省农业结构调整中应着重解决的几个问题

我国加入WT0以后，广大农村干部群众对于加速农业结构调整，以适应世界贸易组织规则的认识逐步深刻。针对农业结构调整过程中的新生产出的农产品卖难的现象进行了分析探讨，并提出应采取的措施和对策。     

一种基于模糊概率推理和遗传算法相结合的变压器故障诊断研究

在概率因果推理模型的基础上,引入模糊理论,重新建立了模糊概率因果变压器故障诊断模型,并从非线性组合优化的角度提出了该模型的GA求解策略。这对较快、较准确地搜索变压器故障提供了一种新的思路。实验数据表明:该文提出的新方法同时提高了并发性故障和单故障的识别率。     

正交法合成邻硝基苯酚最佳反应条件实验探讨

以苯酚硝酸钠和浓硫酸为原料，合成邻硝基苯酚和对硝基苯酚，产率一般很低，讨论了以硝酸钠和浓硫酸为原料，在醋酸介质下进行硝化反应合成邻硝基苯酚同时提取对硝基苯酚。通过正交法确定最佳反应条件，并对实验结果进行讨论。     

电位滴定法在环境监测中的应用

本文简要介绍了运用电位滴定法对水中Ca2 ，Mg2 ，Cl-及F-离子进行测定，利用化学计量点时电位的突跃来确定终点．方法简便、快速、灵敏、准确，符合定量分析要求，可用于环境监测之中．     

关于有限域的一种具体构作

论述了元素在二百个以内的有限域的数目、结构和部分的矩阵表示。     

SiCp/Al复合材料制备工艺对组织与性能的影响

采用高能球磨粉末冶金法制备了体积分数为15％SiCp／2009Al复合材料，研究了球磨转速、球磨时间对复合材料组织和性能的影响。结果表明，球磨转速和球磨时间是影响复合材料力学性能的重要因素，较长时间高转速球磨使得SiC颗粒均匀分布，转速190r／min、球磨6h制备的复合粉末经真空热压、挤压后的复合材料SiC颗粒均匀分布，材料的抗拉强度高达650MPa，伸长率大于5％。     

Effects of tilt on high-resolution ADF-STEM imaging

A study of the effects of small-angle specimen tilt on high-resolution annular dark field images was carried out for scanning transmission electron microscopes with uncorrected and aberration-corrected probes using multislice simulations. The results indicate that even in the cases of specimen tilts of the order of 1 degree a factor of 2 reduction in the contrast of the high-resolution image should be expected. The effect holds for different orientations of the crystal. Calculations also indicate that as the tilted specimen gets thicker the contrast reduction increases. Images simulated with a low-angle annular dark field detector show that tilt effects are more pronounced in this case and suggest that these low-angle detectors can be used to correct specimen tilt during scanning transmission electron microscopes operation.     

Optical and thermal processes involved in ultrafast laser pulse interaction with a field emitter

In the interaction between ultrafast laser pulses and a field emitter both optical and thermal processes are involved. In this paper, these physical process, and their timescales, are experimentally explored. Simple models are proposed to explain the observed experimental behaviour, and the influence of various parameters are investigated. In the case of optical processes, it is shown that the optical field is greatly enhanced at the tip apex, and that field evaporation could be induced by an optical non-linear effect called optical rectification. In the case of thermal processes, it is shown that the temperature rise because of light absorption can be determined and that the cooling process of the tip surface can be studied by pump probe measurements.     

硫酸高铈与对二甲苯反应的动力学研究

本工作测定了不同温度下硫酸高铈与对二甲苯反应的速率常数及表观活化能Ｅａ＝ １１１．５ｋＪ·ｍ ｏｌ－ １。在动力学测定的的基础上确定了此反应的速率方程为ｄ［ＰＴＡＬ］／ｄｔ＝ ｋ［ＰＸ］［Ｃｅ（ＩＶ）］