以功能为导向的插层结构功能材料结构设计及应用

插层结构功能材料是近年来迅速发展的一类新型功能材料。北京化工大学化工资源有效利用国家重点实验室多年来以插层结构功能材料的研究为基础,针对＂以功能为导向的结构设计＂等关键科学问题展开了大量基础和应用研究,实现了对材料微观主客体的设计和介观、宏观结构的调控,制备了多种新型插层结构功能材料,广泛应用于催化、环保、医药、纺织、...     

全光谱原子发射光谱技术的特点与应用

对全光谱原子发射光谱法的特点和应用以及其基本原理作了较详细的介绍,引用文献24篇。     

Progress of Thioi-based Click Reaction

巯基参与的点击反应具有简单、快速、无金属催化等优点。本文介绍了巯基点击反应的反应机理,着重对近年来新出现的巯基点击反应的概念、特点进行分类介绍,并综述了巯基点击反应在材料与分子设计方面的应用,最后对其发展前景进行了展望。     

聚苯硫醚热交联特性研究进展

聚苯硫醚是一种具有典型交联特性的半结晶型热塑性聚合物,在不同气氛条件下进行热处理会发生不同程度的热交联、链增长、氧化交联和氧化反应,热处理后的PPS树脂分子量增加,热稳定性提高,结晶性能也会发生变化。主要围绕PPS树脂热交联处理的机理研究及其在工程上的应用,重点阐述了不同热处理条件对PPS树脂性能的影响及其与工程应用的结合。对PPS树脂后处理过程中存在的问题进行总结,提出了将热交联处理和增韧结合起来同步完成的研究思路。     

表面等离子体共振生物传感器及其应用

表面等离子体共振(Surface Plasmon Resonance,SPR)生物传感器在检测生物分子特异性结合方面具有的高灵敏度、免标记及检测快速等优点,使其在过去的20年中在生命科学、医药科学、食品安全等领域取得了快速发展。本文对SPR生物传感器进行了简要介绍,并着重对其在生命科学、医药学、环境分析、食品安全等领域的应用进行了综述,最后对该领域的研究前景进行了展望。     

Fast Ewald summation for Stokesian particle suspensions

We present a numerical method for suspensions of spheroids of arbitrary aspect ratio, which sediment under gravity. The method is based on a periodized boundary integral formulation using the Stokes double layer potential. The resulting discrete system is solved iteratively using generalized minimal residual accelerated by the spectral Ewald method, which reduces the computational complexity to , where N is the number of points used to discretize the particle surfaces. We develop predictive error estimates, which can be used to optimize the choice of parameters in the Ewald summation. Numerical tests show that the method is well conditioned and provides good accuracy when validated against reference solutions. Copyright © 2014 John Wiley & Sons, Ltd.     

Development of an efficient statistical volumes of fluid–Lagrangian particle tracking coupling method

The breakup of a liquid jet into irregular liquid structures and droplets leading to the formation of a dilute spray has been simulated numerically. To overcome the shortcomings of certain numerical methods in specific flow regimes, a combined approach has been chosen. The intact liquid core, its primary breakup and the dense spray regime are simulated using the volumes of fluid (VOF) method in combination with LES, whereas the Lagrangian particle tracking (LPT) approach in the LES context is applied to the dilute spray regime and the secondary breakup of droplets. A method has been developed to couple both simulation types on a statistical basis. This statistical coupling approach (SCA) reflects the dominating physical mechanisms of the two‐phase flow in each regime to a high degree. The main benefit of the SCA is computational efficiency as compared with the more straightforward approach where one follows each structure, denoted here as the direct coupling approach. The computational benefits stem from the reduction of computational time since the VOF simulation is run only until statistical convergence and not during the whole spray development. A second benefit using the SCA is the possibility to use the stochastic parcel method in the LPT simulation whereby a large number of droplets may be handled. The coupling approach is applied to the atomization of a fuel jet in a high pressure chamber, demonstrating the gain of efficiency of the SCA as compared with direct coupling approach. Copyright © 2014 The Authors. International Journal for Numerical Methods in Fluids published by John Wiley & Sons Ltd.     

Short-Time Existence for Some Higher-Order Geometric Flows

We establish short-time existence and regularity for higher-order flows generated by a class of polynomial natural tensors that, after an adjustment by the Lie derivative of the metric with respect to a suitable vector field, have strongly parabolic linearizations. We apply this theorem to flows by powers of the Laplacian of the Ricci tensor, and to flows generated by the ambient obstruction tensor. As a special case, we prove short-time existence for a type of Bach flow.     

Regularity Criterion for Solutions of Three-Dimensional Turbulent Channel Flows

In this paper we consider the three-dimensional Navier–Stokes equations in infinite channel. We provide a regularity criterion for solutions of the three-dimensional Navier–Stokes equations in terms of the vertical component of the velocity field.     

A variational approach to nonlinear and interacting diffusions

Abstract

The article presents a novel variational calculus to analyze the stability and the propagation of chaos properties of nonlinear and interacting diffusions. This differential methodology combines gradient flow estimates with backward stochastic interpolations, Lyapunov linearization techniques as well as spectral theory. This framework applies to a large class of stochastic models including nonhomogeneous diffusions, as well as stochastic processes evolving on differentiable manifolds, such as constraint-type embedded manifolds on Euclidian spaces and manifolds equipped with some Riemannian metric. We derive uniform as well as almost sure exponential contraction inequalities at the level of the nonlinear diffusion flow, yielding what seems to be the first result of this type for this class of models. Uniform propagation of chaos properties w.r.t. the time parameter is also provided. Illustrations are provided in the context of a class of gradient flow diffusions arising in fluid mechanics and granular media literature. The extended versions of these nonlinear Langevin-type diffusions on Riemannian manifolds are also discussed.