一种简便快速的电子衍射谱分析方法

本文根据特征平行四边形法和N/(1/2)比值法提出了一种简便快速的电子衍射谱分析方法——图表法,由于它以一些简单的操作取代了常用分析法的数据测量和计算过程,因此具有简便、快速、可靠性高等优点。     

用格子Boltzmann方法模拟涌波的反射与绕射

本文应用格子Boltzmann模型建立离散动力学模型,并利用Chapman Enskog对模型的方程组进行展开,建立了模拟二维浅水动力学的方程组。在从理论上证明了它严格地满足质量和动量的基本守恒定律的基础上,应用所建立的模型进行数值试验,模拟了溃坝涌波现象及其与固壁和建筑物的相互作用。利用这一模型计算了溃坝波与水中方柱和圆柱的相互作用,以及明渠内的涌波的反射和绕射复杂流场。该模型具有显式的表达形式,易于编程应用;粒子运动是彼此独立的,适合于并行数值计算;边界条件易于处理;易于处理多相流动微观机制等优点。     

模糊层次分析法确定管线风险因素权重

采用美国W.K.Muhlbauer提出的管线风险因素评分法,用模糊层次分析法和改进层次分析法分别计算其权重,并与层次分析法得到的结果进行比较,得出如下结论①层次分析法和改进层次分析法计算得到的结果并不理想,甚至严重偏离W.K.Muhlbauer提出的权重;②模糊层次分析法计算得到的结果和W.K.Muhlbauer提出的权重非常吻合;③层次分析法存在需要检验判断矩阵一致性的缺陷,改进层次分析法存在步骤繁琐,操作不便的缺陷;④模糊层次分析法可以应用于管线风险因素和其他类似因素权重的确定。     

Characterization survey of Ga<Subscript>x</Subscript>In<Subscript>1−x</Subscript>As/InAs<Subscript>y</Subscript>P<Subscript>1−y</Subscript> double heterostructures and InAs<Subscript>y</Subscript>P<Subscript>1−y</Subscript> multilayers grown on InP

Low-bandgap, lattice-mismatched Ga_xIn_1−xAs (GaInAs) grown using InAs_yP_1−y (InAsP) compositional-step grades on InP is a primary choice for lightabsorbing, active layers in high-efficiency thermophotovoltaic (TPV) devices. The GaInAs/InAsP double heterostructures (DHs) show exceptional minority carrier lifetimes of up to several microseconds. We have performed a characterization survey of 0.4–0.6-eV GaInAs/InAsP DHs using a variety of techniques, including transmission electron microscopy (TEM). Dislocations are rarely observed to thread into the GaInAs active layers from the InAsP buffer layers that terminate the graded regions. Nearly complete strain relaxation occurs in buried regions of the InAsP grades. The buffer-layer strain prior to deposition of the active layer is virtually independent of the net misfit. Foreknowledge of this buffer-layer strain is essential to correctly lattice match the buffer to the GaInAs active layer.     

The role of grain boundary plane orientation on intergranular corrosion of symmetric and asymmetric [1 1 0] tilt grain boundaries in directionally solidified pure copper

Susceptibility to intergranular corrosion of asymmetric grain boundaries in pure copper was well correlated with a geometric criteria, i.e. the effective interplanar spacing of grain boundaries rather than coincidence site lattice (CSL) scheme if we rationally assume that the grain boundary structure relaxes to be formed by low-index planes, therefore resulting in high interplanar spacing.     

CONTINUOUS THERMODYNAMICS FOR POLYMER SOLUTIONS I.CLOSE-PACKED LATTICE MODEL

using close-packed lattice models,a continuous thermodynamic framework is presented forphase-equilibrium calculations for binary solutions with a polydisperse polymer solute.An expressionfor the Helmholtz function of mixing is based on the revised Freed model developed previously.Asize parameter c_r and an energy parameter ε are used;the former can be temperature dependent,while the latter can depend on both temperature and chain-length of the polymer.The discretemulticomponent approach is adopted to derive expressions for chemical potentials,spinodals and criti-cal points.The continuous distribution function is then used in calculations of moments occurring inthose expressions.Computation programs are established for cloud-point-curve,shadow-curve,spinodal and critical-point calculations for polymer solutions with standard distribution or arbitrarydistribution of polymer.In the latter case,the derivative method developed previously is applied.lllustrations for phase-equilibrium calculations are shown     

水热处理后FCC催化剂及Y型沸石的裂化活性及其物化性质表征

采用DTA、XRD、^27Al NMR和吡啶吸附-IR等方法，对水热处理后在不同条件下存放的两种FCC催化剂及相应的Y型沸石分别进行了物化性质表征。结果表明，经水热处理后在空气气氛下放置时，沸石易于吸附环境中的水分形成一定量的表面水，并将表面水进一步极化成以活性羟基形式存在的结构水，从而使总酸量提高；同时，在空气气氛中放置吸水后，沸石骨架中可能发生了晶格重排，部分非骨架铝转变为骨架铝，使晶胞常数略有增加。对水热处理后不同存放条件下FCC催化剂的裂化活性变化规律及其物化性质进行了关联。     

正丁烷选择氧化制顺酐钒磷氧化物催化剂的研究进展

综述了正丁烷选择氧化制顺酐钒磷氧化物(VPO)催化剂的研究进展。介绍了在催化剂前体制备过程中添加助剂以及负载 VPO 对 VPO 催化剂微观结构和性能的影响,分析了 VPO 催化剂的物相组成及各物相在催化反应中的作用,讨论了正丁烷选择氧化制顺酐的反应机理,指出采用活性位理论指导 VPO 催化剂的研制、提高活性化数量、增加可逆储氧量是未来 VPO 催化剂研究的发展方向。     

河流生态功能综合评价的层次决策分析方法

介绍了基于层次决策分析的河流生态功能综合评价方法,提出了在河流水文评估、物理化学评估、生物栖息地质量评估和生物评估4个单项评估的基础上,构建以河流生态功能综合指数为目标、4个单项因子为准则、5个等级标度为决策标准的层次递阶模型,应用模型进行了河流综合评价的两种情景分析。     

煤矿底板突水危险性投影寻踪综合评价模型

煤矿底板突水问题是一个复杂系统。提出了基于投影寻踪方法综合分析的新思路来探求煤矿底板突水机制,建立了突水危险性综合评价的投影指标函数,并采用实码加速遗传算法来优化模型参数。实际应用于肥城矿区底板突水危险性的综合评价,取得了理想的结果,且结论与层次分析法吻合,表明投影寻踪新方法应用于煤矿底板突水危险性的综合评价是可行的。