三嵌段聚电解质水溶液在圆柱受限空间内的相行为

聚电解质是一种典型的软物质,兼具聚合物与电解质的双重特征,在药物输送、燃料电池膜、纳米涂覆等方面的应用有着广泛的应用前景。不同于中性高分子,聚电解质在相分离过程中必须考虑长程的静电相互作用。基于平均场动态密度泛函理论,并采用局域电中性条件处理静电相互作用,对浓度不同的三嵌段聚电解质的水溶液进行了模拟计算。通过改变聚电解质浓度,一些典型的相结构,如层状相、双连续相、六角柱状相、球形胶束等被获得。为了研究聚电解质溶液在受限空间内的相行为,将不同浓度的聚电解质溶液放入圆孔内进行模拟。结果表明,当嵌段的电量发生改变,体系能够形成堆叠的圆盘、单螺旋、有洞的层状相等有序微观结构。此外,随着嵌段的电量增加,受限空间内得到的有序结构逐渐被破坏,最终消失。通过定义疏水嵌段的序参量,确定了各浓度聚电解质溶液体系的有序-无序转变临界电量。本工作得到的一些结果将对新型纳米材料的研究工作具有一定的指导意义。     

嵌段共聚物受限自组装结构的计算机模拟和理论预测

本文简述高分子自组装的几种计算机理论模拟方法.重点叙述用模拟方法去模拟和预测嵌段共聚物受限诱导自组装结构的情况.总结它们在一维、二维以及三维受限条件下自组装的理论预测和模拟的研究成果,并指出了在受限条件下自组装的研究中亟待解决的问题.     

嵌段共聚物球形胶束体系的标度理论及其与均匀场理论的对比研究

本文建立了用于嵌段共聚物胶束体系定量计算的标度理论模型,讨论了标度理论与均匀场模型的差异。在极性和非极性溶剂体系中,定量考察了平衡态胶束聚集数、胶束过渡区聚合物浓度分布、胶束半径和内界面处的聚合物浓度等平衡性质,以及嵌段共聚物嵌段比例、摩尔质量等因素对上述性质的影响。与实验及均匀场模型的对比结果硅示,均匀场模型的拟均相假设对胶束聚集数等平衡性质的计算不会产生显著偏差,标度理论模型与均匀场模型都能够较好地描述胶束体系,两模型也获得了较好的一致。此外,标度理论模型能够给出胶束内的浓度分布。即使在高聚集数的情况下,胶束内界面处溶剂的含量仍然很高（〉50％）,这表明有必要对内界面张力的计算进行修正,而均匀场模型则忽略了此项修正。     

聚硅氧烷嵌段共聚物中微相分离的计算机模拟

通过RIS Metropolis Monte-Carlo方法建立了PDMS、PDPS以及嵌段共聚物PDMS/PDPS的模型,并用COMPASS力场和智能最小化方法对模型进行了能量最小化计算。采用共混相图、红外光谱和X射线的方法研究了PDMS/PDPS嵌段共聚物的微相结构,结果表明PDMS和PDPS存在微相分离现象;在PDMS/PDPS共聚物结构中,稳定的螺旋结构在与具有无规线团结构的PDMS共聚后,受到部分破坏,形成了新的无规线团区,具有特定的微相结构。     

应用定量构效关系方法预报PEO-PPO-PEO嵌段共聚物的CMC和CMT

以PEO-PPO-PEO嵌段共聚物的PO嵌段数和PO/EO嵌段数之比作为描述符,建立了两参数临界胶团浓度QSPR模型,模犁具有物理化学意义,与Tanford热力学模型反映的胶团聚集的结论一致,可以反映出不同的嵌段共聚物结构对其胶团化自由能的贡献.以嵌段共聚物EO数和表面张力建立了两参数临界胶团温度QSPR模型.本文建立的QSPR模型的数学形式简单,可以快速得到PEO-PPO-PEO嵌段共聚物的聚集数据,具有很好的预报能力,与实验值相关性明显优于文献中的热力学经验模型.     

稳态活性自由基共聚物微观结构模拟的计算机程序设计

为了研究活性自由基共聚物结构,通过一个新的稳态活性自由基共聚模型,用C 语言设计了一个计算机程序,利用此程序可模拟生成ATRcP增长反应链,并获得活性自由基共聚产物的共聚组成、平均段长、链段长度分布,以及元组浓度等反映共聚物微观结构的重要信息。     

自洽场理论研究嵌段聚合物的并行算法实现

自洽场理论的数值计算方法在聚合物热力学的研究中得到了广泛的应用,尤其应用在嵌段共聚物微相分离形态的预测和描述方面[1～6]。该理论方法灵活性较强,参数空间的调整范围较大,能应用的计算体系也变化多样,难以建立固定的既有软件包,现有文献也鲜见针对该理论算法并行化的研究。本文就该理论在嵌段共聚物自组装问题上的数值计算的并行算法实现进行了研究和讨论,给出了算法性能的理论分析,并进行了实验测试。测试结果显示,本文提出的并行算法可获得良好的并行加速比,并行效率较高。该算法的提出有助于推动包括针对聚合物在内的软物质理论的研究工作。     

基于GPU加速的定向凝固相场模拟计算研究

相场法作为一种极具优势的微观组织数值模拟方法,已经在凝固微观组织演化机制的研究中得到了广泛应用。然而无论是从计算尺度还是微观组织演化时间上考虑,相场模拟计算量均非常大,对计算机有着非常高的要求。相对于传统的中央处理器(CPU)计算,图形处理器(GPU)计算是最近发展的一种高效计算手段。提出了一种基于GPU加速的定向凝固相场模拟计算策略,实现了大尺度条件下的定向凝固界面形态演化的加速计算。计算结果表明,对于单个计算机,GPU计算与CPU计算的加速比可以高达30余倍。GPU加速将为相场模拟的发展及应用带来新的契机。     

智能凝胶色谱测定苯乙烯—环氧丙烷嵌段共聚物的结构参数

本文运用高效GPC柱,UV和RI双检测器联用,表征了苯乙烯—环氧丙烷嵌段共聚物的分子量、分子量分布及组成分布。     

基于分子力学的蛋白质分子场可视化

分子场是研究分子结构与功能的重要工具之一,已经成为药物设计和分子对接的常规方法。分子间作用力分布在3维空间,现有的蛋白质显示方法,如范德华表面,分子表面,球棍模型等,都难以对分子间作用力进行空间可视化分析。分子间各种相互作用中,静电力和范德华力在许多生物过程中都扮演着重要的角色,对蛋白质静电相互作用和范德华相互作用的正确计算模拟有着重要的理论和实践意义。分子场的计算分析从蛋白质分子结构出发,先经过分子模拟采样计算得到分子场,再对分子场进行可视化分析,提出针对分子场特点的分步式传输函数设计法,直观地反映了分子场在空间的分布,对于分析蛋白质结构功能、了解分子间相互作用机理以及进行药物设计和分子对接都有重要作用。     

PVDF及其共聚物的压电性和制备

分析了ＰＶＤＦ及其共聚物的压电机理，指出这些高聚物的压电性来自铁电体相的存在。在此基础上，探讨了提高聚合物压电性的制备方法。     

Birefringent properties of cyclic block copolymers and low‐retardation‐film development

Abstract— Cyclic block copolymers (CBCs) are a new class of optical polymers made by fully hydrogenating block copolymers of styrene and conjugated diene. This class of materials has excellent optical transparency, photostability, and good thermal resistance. By changing the copolymer composition and the resulting block‐copolymer morphology, a unique set of birefringence properties can be achieved. The focus of this work was to study various sources of birefringence in block copolymers using a series of model CBC materials. One particularly interesting finding relates to the development of an ultra‐low‐phase‐retardation CBC film. Unlike the conventional approach of using an additive or blend, a CBC film prepared by melt extrusion can readily achieve near‐zero retardation in both the film plane and thickness direction. This nearly isotropic CBC film is useful as a polarizer protection film in flat‐panel displays. When used as the inner protective layer of a polarizer, CBC film helps to reduce the color shift of IPS‐LCDs at oblique angles and offer a wider viewing angle.     

一种基于单演相位局部差分二值模式的人脸识别方法

提出一种融合单演方向和尺度间互补信息的单演相位局部差分二值模式的人脸识别方法。该方法首先提取图像的单演相位,对单演相位进行局部差分,求绝对值,并进行二值编码;接着对单演方向和相位尺度间对应的相位点进行二值编码;然后将单演方向编码、相位尺度间编码、同一尺度的单演相位差分二值编码按顺序排列形成单演相位差分模式;最后采用统计学的方法形成单演相位差分二值模式映射表,并将单演相位编码进行映射,从而达到保留主要特征模式、降低特征维度的目的。在ORL和CAS PEAL人脸库上的实验表明,该方法具有很好的识别性能。     

Robust hybrid supervisory control for spacecraft close proximity missions

We consider the problem of rendezvous, proximity operations, and docking of an autonomous spacecraft. The problem can be conveniently divided into three phases: (1) rendezvous phase; (2) docking phase; and (3) docked phase. On each phase the task to perform is different, and requires a different control algorithm. Angle and range measurements are available for the entire mission, but constraints and tasks to perform are different depending on the phase. Due to the different constraints, available measurements, and tasks to perform on each phase, we study this problem using a hybrid systems approach, in which the system has different modes of operation for which a suitable controller is to be designed. Following this approach, we characterize the family of individual controllers and the required properties they should induce to the closed-loop system to solve the problem within each phase of operation. Furthermore, we propose a supervisory algorithm that robustly coordinates the individual controllers so as to provide a solution to the problem. In addition, we present specific controller designs that appropriately solve the control problems for individual phases and validate them numerically.     

Quantum fixed-point search algorithm with general phase shifts

Grover presented the Phase-?/3 search by replacing the selective inversions by selective phase shifts of ?/3. In this paper, we review and discuss the fixed-point search with general but equal phase shifts and the fixed-point search with general but different phase shifts.     

L-丙交酯和D,L-丙交酯共聚物立体化学构型的计算机模拟

运用Monte Carlo法,模拟D,L-丙交酯(DLLA)与L-丙交酯(LLA)共聚体系,在不同投料比情况下的立体化学构型,计算了两种立体异构体在共聚高分子链中所占的比例,与各种异构体序列的长度分布;计算了轮数R;分析了竞聚率r和投料比p对DLLA-LLA共聚物的立体化学结构的影响,发现r直接影响立体异构序列的交替程度;计算了共聚链上四单元组和六单元组的含量,引用文献提供的13C NMR谱图进行验证;研究了共聚组成、重均序列长度等模拟结果与某些物性实验数据之间的关系,发现共聚物的结晶速率和一定范围内的重均序列长度有关。     

Deep Line Drawing Vectorization via Line Subdivision and Topology Reconstruction

Vectorizing line drawing is necessary for the digital workflows of 2D animation and engineering design. But it is challenging due to the ambiguity of topology, especially at junctions. Existing vectorization methods either suffer from low accuracy or cannot deal with high‐resolution images. To deal with a variety of challenging containing different kinds of complex junctions, we propose a two‐phase line drawing vectorization method that analyzes the global and local topology. In the first phase, we subdivide the lines into partial curves, and in the second phase, we reconstruct the topology at junctions. With the overall topology estimated in the two phases, we can trace and vectorize the curves. To qualitatively and quantitatively evaluate our method and compare it with the existing methods, we conduct extensive experiments on not only existing datasets but also our newly synthesized dataset which contains different types of complex and ambiguous junctions. Experimental statistics show that our method greatly outperforms existing methods in terms of computational speed and achieves visually better topology reconstruction accuracy.     

Quantum fixed-point search algorithm with general phase shifts

Grover presented the Phase-π/3 search by replacing the selective inversions by selective phase shifts of π/3. In this paper, we review and discuss the fixed-point search with general but equal phase shifts and the fixed-point search with general but different phase shifts.     

Quantum correlation and quantum phase transition in the one-dimensional extended Ising model

Quantum phase transitions can be understood in terms of Landau’s symmetry-breaking theory. Following the discovery of the quantum Hall effect, a new kind of quantum phase can be classified according to topological rather than local order parameters. Both phases coexist for a class of exactly solvable quantum Ising models, for which the ground state energy density corresponds to a loop in a two-dimensional auxiliary space. Motivated by this we study quantum correlations, measured by entanglement and quantum discord, and critical behavior seen in the one-dimensional extended Ising model with short-range interaction. We show that the quantum discord exhibits distinctive behaviors when the system experiences different topological quantum phases denoted by different topological numbers. Quantum discords capability to detect a topological quantum phase transition is more reliable than that of entanglement at both zero and finite temperatures. In addition, by analyzing the divergent behaviors of quantum discord at the critical points, we find that the quantum phase transitions driven by different parameters of the model can also display distinctive critical behaviors, which provides a scheme to detect the topological quantum phase transition in practice.     

A novel phase performance evaluation method for particle swarm optimization algorithms using velocity-based state estimation

The searching process of particle swarm optimizations (PSO) includes four states: exploration, exploitation, convergence and jump-out. Performance information of each state is essential to learn the characteristics of different algorithms as well as to improve their performances. To this end, this paper discusses a novel performance evaluation method of each phase in PSOs. Firstly, we propose a velocity-based state estimation (VSE) method, which can estimate the real-time state of PSO variants with less computation. Subsequently, we provide a phase performance evaluation based on VSE, which includes phase identification, two kinds of phase performance indicators and ranking method. Finally, we design hybrid algorithm experiments, to compare phase performance of six main PSO algorithms, and the phase replacement experiments is used to verify the experimental results.