耗散粒子动力学及其应用的新进展

耗散粒子动力学(dissipative particle dynamics,DPD),是1992年提出的一种针对于复杂流体的介观模拟方法,凭着相对于其它模拟方法的高计算效率以及能够模拟流体水力学行为的优势,目前已经成为研究复杂流体动力学行为的主要模拟方法之一,同时也是联系微观结构与宏观实验的重要桥梁,在辅助研究复杂流体性质方面起到了重要的作用,本文对这一模拟方法在近几年的发展及其应用做了全面的总结。首先介绍了近年来方法本身的改进和完善,接着详细总结了目前的应用研究热点。作为一种计算机实验工具,这种方法近年来在对复杂流体的研究上进展迅速,既能用于预测平衡过程的结构和性质,又能用于研究非平衡过程的动力学因素。     

多组分体系相图中的杠杆原理形式

讨论了两相和三相多组分体系中杠杆原理的两种形式。对两组分体系,利用三相线上的杠杆原理关系式和凝固点降低公式,解释了熔化物体系冷却过程中的步冷曲线。另外,还讨论了三组分体系相图中,同一直线段上三个物系点之间的类杠杆原理关系式。该关系式可以用于不同浓度溶液的配制和三相体系相图的绘制。     

波长位移法在多组分混合物测定中的应用

作者根据吸收光谱具有的全息性,首次提出采用波长位移,选择适当的入射光波长,吸光值通过简单计算,同时测定多组分混合物中成分的方法。文中以测定饮料中食用合成色素为例,对方法的可行性、实用性进行了验证,结果表明,此法为吸收光光度法提供了又一种实用的分析技术。     

多组分反应在合成含肽类药物开发中的应用

多组分反应可以快速大量的合成结构复杂的药物分子,因此现代药物开发与多组分反应的发展密切相关。本文总结了近年来国内外有关多组分反应研究的发展概况及其在含肽链类新药物开发中的应用研究进展。     

丙二腈在多组分反应中的应用*

丙二腈分子中的氰基作为强吸电子基团活化亚甲基,也是良好的离去基团,以及氰基的碳氮三键可进行加成反应,使得丙二腈是一种非常特别的化合物。它具有非常丰富的反应性质,可以发生Knoevenagel缩合、Michael加成、环化和消去等反应,是进行多组分合成反应的优良试剂。由其参加的多组分合成反应已经成为合成众多碳环和杂环化合物的重要方法。本文综述了丙二腈在多组分反应中的研究进展,介绍了近年来丙二腈参加的多组分反应合成环状化合物的成功事例,展望了丙二腈反应的发展方向。     

耗散粒子动力学和纳维边界条件在微米纳米流体力学模拟中的应用

耗散粒子动力学是一种粗粒化的计算模拟方法,在微米和纳米流体力学中有着广泛的应用.由于界面在微小体积流体中的重要性,边界条件的选取在微米和纳米流体的研究中起到了关键性的作用.我们简单地介绍了耗散粒子动力学的模拟方法,并以此为基础,介绍了能够实现纳维边界条件的可调滑移长度的边界条件模拟方法.通过条纹状图案修饰的超疏水表面的流体力学行为研究,和高分子链在微米纳米流体器件中的运动研究2个例子,耗散粒子动力学结合纳维边界条件的模拟方法的实用性和可靠性得到了证实.     

分子印迹聚合物在复杂体系分离中的应用研究进展

分子印迹聚合物的高选择性使其在复杂体系样品的净化富集中具有很强的应用潜力通过文献综述了分子印迹聚合物在固相提取中的应用．介绍了目前各种印迹聚合物制备方法,提出了在样品净化富集中选择淋洗条件需要考虑的问题及分子印迹聚合物在复杂体系分离中应用的发展前景。     

均聚物链吸附在胶束表面上的非平衡态耗散粒子动力学

利用平衡态耗散粒子动力学（Dissipative Particle Dynamics, DPD）方法,研究了嵌段共聚物自组装形成胶束以及均聚物链在其表面的吸附。进一步采用非平衡态耗散粒子动力学（Non-Equilibrium Dissipative Particle Dynamics, NEDPD）方法,通过加入剪切,研究了均聚物的脱落和胶束的分裂过程。模拟结果揭示了脱落时间随剪切速率的变化规律。     

重质油胶体聚集结构的耗散粒子动力学模拟

重质油是以沥青质为胶核分散于饱和油分中形成的极其复杂的胶体体系.本文采用耗散粒子动力学(DPD)方法研究重质油的胶体结构及其影响因素.根据重质油各组分的分子结构特征,构建了描述重质油组分的粗粒化模型化合物.模拟结果表明,本文构建的粗粒化模型能很好地反映重质油的胶体聚集结构.沥青质分子结构对胶体聚集结构有序性有显著影响,较高稠合程度的芳香环结构将使胶束结构有较高的有序性,烷基侧链则表现出分散作用.重质油中的胶质具有胶溶作用,胶质与沥青质的浓度比存在一个极限,当小于这个极限时,重质油将出现聚沉.     

双金属氰化物在多组分偶联反应中的催化活性(英文)

Several dual metal cyanide catalysts were prepared from potassium ferrocyanide,metal chloride(where metal = Zn2+,Mn2+,Ni2+,Co2+ and Fe2+),t-butanol(complexing agent) and PEG-4000(co-complexing agent).The catalysts were characterized by elemental analysis(CHN and X-ray fluorescence),X-ray diffraction,N2 adsorption-desorption,scanning electron microscopy,Fourier-transform infrared spectroscopy,and UV-Visible spectroscopy.The dual metal cyanide catalysts were used in several acid catalyzed multi-component coup...     

淀粉乳液形成过程主要影响因素的耗散粒子动力学模拟与实验

以环己烷为油相、淀粉乳液为水相、Span60和Tween60为乳化剂, 用耗散粒子动力学(DPD)方法研究了淀粉乳液形成过程及油水比、乳化剂用量等因素对淀粉乳液形成的影响. 结果表明, 模拟6000步时, 体系达到平衡状态; 乳滴的粒径随乳化剂含量的增加先减小而后增加, 随淀粉含量的增加而增加, 随环己烷含量的减小而增加; 形成稳定淀粉乳液体系的参数范围: 7＜油水比≤20, 9%＜乳化剂用量≤18%. 实验结果表明, 乳化剂含量为11%～15%时, 微球的粒径随乳化剂含量的增大而减小; 乳化剂含量大于15%时, 微球的粒径反而增大. 实验与模拟的结果吻合.     

Understanding Multicompartment Micelles Using Dissipative Particle Dynamics Simulation

Multicompartment micelles are a new class of nanomaterials that may find wide applications in the fields of drug delivery, nanotechnology and catalysis. Due to their structural complexity, as well as the wide parameter space to explore, experimental investigations are a difficult task, to which molecular simulation may contribute greatly. In this paper, the application of the dissipative particle dynamics simulation technique to the understanding of multicompartment micelles is introduced, illustrating that DPD is a powerful tool for identifying new morphologies by varying block length, block ratio and solvent quality in a systematic way. The formation process of multicompartment micelles, as well as shear effects and the self-assembly of nanoparticle mixtures in multicompartment micelles, can also be studied well by DPD simulation. The present work shows that DPD, as well as other simulation techniques and theories, can complement experiments greatly, not only in exploring properties in a wider parameter space, but also by giving a preview of phenomena prior to experiments. DPD, as a mesoscopic dynamic simulation technique, is particularly useful for understanding the dynamic processes of multicompartment micelles at a microscopic level.

     

遥爪型聚合物交联反应的耗散粒子动力学模拟

利用耗散粒子动力学(Dissipative particle dynamics, DPD)方法研究了稀溶液中遥爪型聚合物的交联反应过程. 考察了体系中交联度、 链长及浓度等因素对反应达到稳态时所形成的网络结构的影响, 并通过计算聚合物交联结合能(U), 统计达到稳态时特征交联结构的数量来判定各因素对体系的作用. 结果表明, 交联度决定体系的微观结构, 而聚合物链长决定交联结构的连通性. 另外, 特征环形结构数与遥爪型聚合物的浓度及链长均存在线性依赖关系.     

Dissipative Particle Dynamics Simulation of Onion Phase in Star-block Copolymer

A dissipative particle dynamics simulation technique was used to investigate the effect of molecular architecture of star-block copolymer on the patterned structure in a nanodroplet. With increasing the ratio of solvophilic to block length to solvophobic block length(R_H/T), solvophobic sphere, ordered hexagonal phase, onion phase, perforated onion phase and flocculent phase are formed, respectively. Since onion phase has potential application in controlled drug release, it has received wide attention experimentally and theoretically. Our simulation indicates onion phase forms at a certain R_H/T(close to but less than 1). A star-block copolymer molecule has two conformations in onion phase: either fully located in a shell or shared by two neighboring shells. Central structure affects onion's final shape. The molecular number of the copolymer in each shell is a quadratic function of the shell's radius. The arm number of star-block copolymer has little influence on onion's structure, but slightly affects the solvent content. Additionally, we studied the influence of arm length on onion's structure.     

梳状-线性共聚物自组装的耗散粒子动力学模拟

梳状-线性共聚物在选择性溶剂中可以自组装形成两种不同类型的聚集体, 其中第I类的自组装发生在亲、疏溶剂链之间, 而第II类发生在线性链和梳状亚结构之间. 本工作利用耗散粒子动力学方法, 分别研究了梳状-线性共聚物在侧链和主链选择性溶剂中形成的这两类聚集体, 探讨了侧链长度和侧链数量等对聚集体类型及形貌的影响. 研究表明, 第II类聚集体在侧链长度较短且侧链数量较多时容易形成. 将模拟结果与文献报道的实验结果相比较, 发现两者能较好地吻合. 此外, 本研究获得了一些在实验中较难得到的信息, 有助于进一步理解梳状-线性共聚物的自组装行为.     

Dissipative Particle Dynamics Simulation of Microscopic Properties in Diblock Copolymer Films

Mean-square bond length, root-mean-square end-to-end distance and gyration radius in di-block copolymer films have been studied by dissipative particle dynamics simulations. Re-sults show evident linear trends of any property separately with the thickness of film, the interaction between particles of different types, the repulsion between particle and boundary, except for the dependence of the variations of mean-square bond length on the thickness of film, which exhibits as a wave trend. What's more, the varying trends of mean-square bond length and root-mean-square end-to-end distance can correspond to each other. The density distribution of either component in diblock copolymer film can be controlled and adjusted effectively through its interaction with boundary.     

Dissipative Particle Dynamics Simulations of Polymer Brushes: Comparison with Molecular Dynamics Simulations

Summary: The structure of polymer brushes is investigated by dissipative particle dynamics (DPD) simulations that include explicit solvent particles. With an appropriate choice of the DPD interaction parameters , we obtain good agreement with previous molecular dynamics (MD) results where the good solvent behavior has been modeled by an effective Lennard–Jones potential. The present results confirm that DPD simulation techniques can be applied for large length scale simulations of polymer brushes. A relation between the different length scales and is established.

Polymer brush at a solid–liquid interface.