烤燃条件下HMX/TATB基混合炸药多步热分解反应计算

采用多步热分解反应动力学模型,描述单质炸药热分解反应,提出了多组分网格单元计算方法,对以HMX/TATB为基的多元混合炸药在烤燃条件下的热反应过程进行了计算。通过炸药烤燃实验测量了炸药内部温度,获得了炸药点火时间,验证了计算的准确性。分析了混合炸药组成比例的变化对炸药热反应性能的影响。在HMX/TATB混合炸药热反应阶段,主要是HMX发生分解反应释放热量,TATB的反应量很少,随着混合炸药中TATB含量的增多,炸药的点火时间逐渐增长,点火温度逐渐增高,炸药热安全性增强。

     

下倾管-立管水气严重段塞流数值模拟

针对海洋油气传输中常见的下倾管-立管系统, 采用Brackbill模型模拟气液相界面间表面张力, VOF方法追踪气液两相运动界面, 提出了管内气液两相流数值模拟方法. 在低气液相进口折算速度下, 数值模拟了该种管型下的严重段塞流动现象, 分析了相关物理参数的变化特性. 结果表明, 在严重段塞流下, 管内流型流态、压力、液塞运动速度、立管出口气液相平均速度、下倾管及立管内含气率等均具有明显周期性特征, 而且一个周期内严重段塞流可分为4个阶段, 进而给出了各阶段中相关参数的变化特性. 数值模拟结果与相关文献中的实验结果吻合良好,表明了该数值模拟方法的有效性.      

基于非线性优化的单目视觉/惯性组合导航算法

针对自主移动机器人在GPS拒止环境下准确实时定位的问题,提出一种单目视觉/惯性组合导航算法。为解决视觉/惯导工作频率不一致问题,利用预积分技术预先处理惯性测量值;引入了一种快速高精度线性初始化方法,分步估计初始系统尺度、重力方向、速度及零偏;结合全局地图三维点约束削弱累积误差,基于是否更新地图点,构建了两种基于非线性优化的单目视觉/惯性紧耦合模型,以保证导航的局部精度及全局一致性。实验结果表明:初始化方法可快速(15 s内)实现高精度状态初始化;与单目视觉导航算法相比,提出的算法不仅可获取绝对尺度信息,且导航精度更高;与传统滑动窗口非线性优化方法相比,提出的算法在窗口优化过程中加入全局地图三维点约束,可有效削弱累积误差,验证了算法的正确性和可行性。     

Modulating the properties of quadruple hydrogen bonded supramolecular polymers by photo-cross-linking between the coumarin moieties

Novel linear supramolecular polymers were successfully constructed by self-assemblies of coumarin-bridged bifunctional UPy derivative.Benefitting from the photodimerization ability of the coumarin moieties,the linear supramolecular polymers could form the large three-dimensional polymer networks upon UV light irradiation via photo-cross-linking,which provides a viable and alternative procedure to modulate the properties of supramolecular polymers.     

Intermittency,Moments, and Friction Coefficient during the Subcritical Transition of Channel Flow

The intermittent distribution of localized turbulent structures is a key feature of the subcritical transitions in channel flows, which are studied in this paper with a wind channel and theoretical modeling. Entrance disturbances are introduced by small beads, and localized turbulent patches can be triggered at low Reynolds numbers (Re). High turbulence intensity represents strong ability of perturbation spread, and a maximum turbulence intensity is found for every test case as Re ≥ 950, where the turbulence fraction increases abruptly with Re. Skewness can reflect the velocity defects of localized turbulent patches and is revealed to become negative when Re is as low as about 660. It is shown that the third-order moments of the midplane streamwise velocities have minima, while the corresponding forth-order moments have maxima during the transition. These kinematic extremes and different variation scenarios of the friction coefficient during the transition are explained with an intermittent structure model, where the robust localized turbulent structure is simplified as a turbulence unit, a structure whose statistical properties are only weak functions of the Reynolds number.     

Decision Effects,the Hahn–Jordan Decomposition for States,and Their Connection to Ludwig’s Axiomatic Approach to Quantum Mechanics

We begin with a quantum logic carrying a large collection of states. We then form a dual pair of Banach spaces—base normed and order unit normed—containing the states and the logic, respectively. A Galois connection on the face lattices of the states and the dual positive order unit interval is introduced. The elements of the logic are connected to a dense subset of the extreme points of this order interval in the order unit space using a generalized form of the Hahn–Jordan decomposition theorem. Decision effects are defined and identified with the elements of the original logic. Finally, an important axiom of Ludwig is introduced which ties together all the lattices of Galois closed faces of states, Galois closed order intervals of the positive order unit interval, decision effects, and the original quantum logic. The emphasis here is on the consequences of functional analytic assumptions. The paper concludes with a simple example where Ludwig’s axiom does not hold and we see parts of the theory dissolve. PACS: 02.30.Sa, 03.65.Ta.     

基于宏微结合导向下的“离子反应”单元整体教学设计

以高中化学必修“电离和离子反应”为例,提出了以发展学生宏观辨识与微观探析维度的素养为导向,凸显情境、知识、素养的有效整合,体现“教、学、评”一致性的单元整体教学设计思路和实践操作案例。     

序列结构对液晶共聚酯性能的影响

本文通过熔融酯交换和Schottern-Baumann缩聚反应合成了两类组成相同而序列结构不同的基于对羟基苯甲酸、对苯二甲酸和二元酚的三元共聚酯,用热台偏光显微镜、DSC和X-射线衍射,较详细地研究了序列结构对液晶相类型、转变温度和固态结构等的影响。结果表明,无规共聚酯较规则共聚酯的熔化温度普遍降低;但序列结构的差异并不改变液晶相类型,规则共聚酯和无规共聚酯均为热致向列型液晶,两类共聚酯固态结构的差异可用结构单元的相似性进行解释。