FLOW STRUCTURE FORMATION AND EVOLUTION IN CIRCULATING GAS-FLUIDIZED BEDS

The occurrence of heterogeneous flow structures in gas-particle flows seriously affects the gas-solid contacting and transport processes in high-velocity gas-fluidized beds. Particles do not disperse uniformly in the flow but pass through the bed in a swarm of clusters. The so-called “core-annulus“ structure in the radial direction and “S“ shaped axial distribution of solids concentration characterize the typical flow structure in the system. A computational study, using the discrete particle approach based on molecular dynamics techniques, has been carried out to explore the mechanisms underlying formation of the clusters and the core-annulus structure. Based on energybudget analysis including work done by the drag force, kinetic energy, rotational energy, potential energy, and energy dissipation due to particle-particle and particle-wall collisions, the role of gas-solid interaction and inelastic collisions between the particles are elucidated. It is concluded that the competition between gas-solid interaction and particle-particle interaction determines the pattern formation in high-velocity gas-solid flows: if the gas-solid interaction (under elevated pressure) dominates, most of particle energy obtained by drag from the gas phase is partitioned such that particle potential energy is raised, leading to a uniform flow structure. Otherwise, a heterogeneous pattern exists, which could be induced by both particle -particle collisions and gas-solid interaction. Although both factors could cause the flow instability, the non-linear drag force is demonstrated to be the necessary condition to trigger heterogeneous flow structure formation. As gas velocity increases and goes beyond a critical value, the fluid-particle interaction suppresses particle collisional dissipation, and as a consequence a more homogeneous flow regime is formed.     

Dynamic characteristic analysis of a 3-D semi-submerged body as a fluid-structure interaction system

An Arnoldi‘s method with new iteration pattern, which was designed for solving a large unsymmetric eigenvalue problem introduced by displacement-pressure FE (Finite Element) pattern of a fluid-structure interaction system, was adopted here to get the dynamic characteristics of the semi-submerged body. The new iteration pattern could be used efficiently to obtain the Arnoldi‘s vectors in the shift-frequency technique, which was used for the zero-frequency problem. Numerical example showed that the fluid-structure interaction is one of the important factors to the dynamic characteristics of large semi-submerged thin-walled structures.     

开槽对大跨悬挑平屋盖结构风荷载的影响

本文结合一大跨悬挑平屋盖模型的风洞试验研究，分析了此类结构屋盖的平均局部体型系数和极值局部体型系数的分布特性；并根据其风压的分布特性，提出在悬挑屋盖承受较大负压的屋檐和角点附近这些遇强风易发生破坏的部位采取开槽气动抗风措施，进一步研究了该气动抗风措施对大跨悬挑平屋盖结构风荷载的影响，试验结果显示，它们可以有效地削减屋盖风敏感处的风荷载值，使平均局部体型系数大约降低50％，极值局部体型系数大约降低25％，所得的这些结果对于结构的抗风设计有一定的指导意义。     

磷酸钾缓冲溶液与模型细胞膜相互作用的和频光谱

利用和频光谱技术详细研究了磷酸钾缓冲溶液与带负电荷的生物仿生膜(d₅₄-DMPG磷脂双层膜)相互作用的实时过程．通过监控CD₂、CD₃、磷脂分子头部的磷酸根以及羰基官能团的光谱信号随加入磷酸钾缓冲溶液的实时变化,获得了磷脂双层膜分子结构的动力学变化．结果表明K⁺能够结合到细胞膜上,并且很快地引起了CD₂、CD₃、磷脂头部磷酸根以及羰基官能团信号的变化．根据各官能团的和频信号响应,磷酸钾缓冲溶液很可能是通过在双层膜中形成环形气孔来与磷脂双层膜发生作用．该结果可以很好地解释磷酸钾缓冲溶液环境下的离子协助蛋白质的跨膜过程．     

基于Salagean算子的bi-单叶函数系数估计

讨论和研究了受限于Salagean算子且同时满足:1+1/b((D~(n+1)f(z)/(D~nf(z)))-1)φ(z)和1+1/b((D~(n+1)f~(-1)(ω)/(D~nf~(-1)(ω))-1)Ψ(ω)的bi-单叶解析函数的系数估计问题,这里φ(z)和Ψ(ω)为正实部函数.主要的研究结果直接推广了先前相应工作.     

用偏联系数与态势函数对高校评价的聚类分析

针对高校学生满意度中的"满意""一般""不满意"在客观上是相互联系,相互制约,不断演化着的不确定性系统这一特点,把集对分析中的联系数用于学生满意度的系统性表述;利用联系数的伴随函数-偏联系数对8所985高校学生满意度作潜在发展趋势的聚类分析.结果表明,8所高校的学生满意度的一阶偏联系数全部大于0,其中一所大于1,呈现为向"满意"发展的趋势;但其二阶偏联系数则全部小于1,表明存在负向发展趋势.揭示高校学生满意度系统是一个不进则退的演化系统,需要持续不断地改进当前高校教育教学各方面的工作,才有可能不断提升学生满意度.在上述分析基础上,再结合联系数的势函数和态势函数,把8所高校的学生满意度聚为好(1所)、较好(3所)、一般(4所)3类.     

基于灰模型的区间模糊数时间序列预测

研究了基于灰模型的二元区间和三角模糊数时间序列的预测方法.目前以GM(1,1)模型为代表的灰色预测模型只适用于精确数序列.改进了GM(1,1)模型的定义型方程中的参数形式,使方程能适用于几类常见区间模糊数序列.接着,基于区间模糊数的计算准则,分别具体给出了二元和三角模糊数GM(1,1)模型(BIFGM(1,1)和TFGM(1,1))的预测过程.模型对于区间模糊数的界点序列的发展系数进行了加权平均处理,以此保证了区间模糊数序列发展态势的整体性.最后进行了实例应用,验证了模型的有效性.     

投影寻踪分类建模理论的新探索与实证研究

从理论上分析了正确的投影向量系数(权重)约束条件是∑_(j=1)~2a_j~2=1和1≥0_j≥-1;从理论和实证两个视角证实采用约束条件∑_(j=1)~p a_j~2=1和1≥a_j≥0时逆向指标或对正向指标采用了错误的归一化方式时的权重必定等于"0"。采用正确的约束条件,针对同一密度窗宽R值,实证分析发现和从理论上证明了在投影寻踪分类(PPC)建模中改变指标归一化方式前后,权重是互为相反数的重要特性等三个定理和二个推理,改变指标归一化方式不影响任意两样本投影值之间的距离和投影指标函数值。提出了正确使用PPC进行建模的基本原则和步骤、判定指标属性(正向指标或者逆向指标)的准则等,实现了投影寻踪探索性研究和验证性分析的有机统一。     

变系数拟自回归模型下的测量误差分析

本文对雷达测量误差影响较大的因素进行了分析研究,并将其和雷达测量数据一起建立了变系数拟自回归的统计模型以实现对雷达测量值的纠偏,利用剖面最小二乘法估计模型参数,在一定条件下证明了模型的大样本性质,并结合残差的峰度和偏度构建了区间估计。实际数据的拟合和预测结果显示,我们提出的纠偏方法可将误差减少90%。     

带连续变利率风险模型最终破产概率上界

考虑了带二元连续变利息力的Sparre Andersen风险模型.研究了积累值盈余过程的表达式与性质;在利率递增环境下,利用推广后的调节系数方程组与递归技术推导了最终破产概率的上界,结论表明得到的破产概率上界是更为一般的Lundberg指数上界.