Exact scaling behavior of partially convex vesicles

We solve analytically for the perimeter-area generating functions for two models of vesicles. While from the solution of the first model, staircase polygons, one can easily extract the asymptotic scaling behavior, the exact solution of the second, column-convex polygons, is difficult to analyze. This leads us to apply a recently developed method for deriving the scaling behavior indirectly, utilizing a set of nonlinear differential equations. One result of this work is a nontrivial confirmation of the scaling/universality hypothesis.     

Scaling Behaviour of Two-Dimensional Polygon Models

Exactly solvable two-dimensional polygon models, counted by perimeter and area, are described by q-algebraic functional equations. We provide techniques to extract the scaling behaviour of these models up to arbitrary order and apply them to some examples. These are then used to analyze the unsolved model of self-avoiding polygons, where we numerically confirm predictions about its scaling function and its first two corrections to scaling.     

Multifractal analysis of Brownian zero set

We present a method for the derivation of the generating function and computation of critical exponents for several cluster models (staircase, bar-graph, and directed column-convex polygons, as well as partially directed self-avoiding walks), starting with nonlinear functional equations for the generating function. By linearizing these equations, we first give a derivation of the generating functions. The nonlinear equations are further used to compute the thermodynamic critical exponents via a formal perturbation ansatz. Alternatively, taking the continuum limit leads to nonlinear differential equations, from which one can extract the scaling function. We find that all the above models are in the same universality class with exponents _u =-1/2, _i =-1/3, and =2/3. All models have as their scaling function the logarithmic derivative of the Airy function.     

甲烷团簇与氘团簇的团簇源特性比较

利用瑞利散射法测量了特定喷嘴产生的甲烷团簇及氘团簇的大小随背压的变化曲线。将团簇大小的实验值与Hagena理论进行了比较,当背压超过3 MPa时,两种团簇的实验值都明显高于理论值。实验发现,特定喷嘴在相同的背压下,常温(298 K)甲烷团簇尺寸小于低温(80 K)氘团簇尺寸,而甲烷团簇中氢原子数至少是氘团簇中氘原子数的1.98倍。     

甲烷团簇与氘团簇的团簇源特性比较

利用瑞利散射法测量了特定喷嘴产生的甲烷团簇及氘团簇的大小随背压的变化曲线。将团簇大小的实验值与Hagena理论进行了比较,当背压超过3MPa时,两种团簇的实验值都明显高于理论值。实验发现,特定喷嘴在相同的背压下,常温(298K)甲烷团簇尺寸小于低温(80K)氘团簇尺寸,而甲烷团簇中氢原子数至少是氘团簇中氘原子数的1.98倍。     

Phase diagrams and surface properties of modified water models

The surface properties and phase diagrams are examined for a number of modified water models. In the ‘bent’ family of models where the bond angle is decreased and the network structure is lost the surface tension is lower than in SPC/E water and the critical temperature is lower. In the ‘hybrid’ family of models which are hybrids between SPC/E water and a Lennard–Jones liquid the surface tension and the critical temperature are higher that in SPC/E water. These properties correlate well with the varying ability of the liquids to dissolve hard spheres. The surface potential, on the other hand, is slightly smaller in magnitude in the hybrid models than in SPC/E water because there is slightly less alignment of the dipoles in the surface layer. The degree of molecular alignment in the surface and the consequent surface potential drop is much lower in magnitude in the bent models than in SPC/E water.     

Relativistic polytropic models of charged anisotropic compact objects

In this paper, we introduce new viable solutions to the Einstein-Maxwell field equations by incorporating the features of anisotropic matter distributions within the realm of the general theory of relativity (\begin{document}${\rm GR}$\end{document}). To obtain these solutions, we employed the Finch-Skea spacetime, along with a generalized polytropic equation of state (\begin{document}${\rm EoS}$\end{document}). We constructed various models of generalized polytropes by assuming different values of the polytropic index, i.e., \begin{document}$\eta= \dfrac{1}{2},~ \dfrac{2}{3},~ 1$\end{document}, and \begin{document}$ 2 $\end{document}. Next, numerous physical characteristics of these considered models were studied via graphical analysis, and they were found to obey all the essential conditions for astrophysical compact objects. Furthermore, such outcomes of charged anisotropic compact star models could be reproduced in various other cases including linear, quadratic, and polytropic \begin{document}${\rm EoS}$\end{document}     

Surface and bulk properties of ballistic deposition models with bond breaking

We introduce a new class of growth models, with a surface restructuring mechanism in which impinging particles may dislodge suspended particles, previously aggregated on the same column in the deposit. The flux of these particles is controlled through a probability p$p$. These systems present a crossover, for small values of p$p$, from random to correlated (KPZ) growth of surface roughness, which is studied through scaling arguments and Monte Carlo simulations on one- and two-dimensional substrates. We show that the crossover characteristic time _t×$t_{\times }$ scales with p$p$ according to _t×∼p^−y$t_{\times }\sim p^{-y}$ with y=(n+1)$y=(n+1)$ and that the interface width at saturation _Wsat$W_{sat}$ scales as _Wsat∼p^−δ$W_{sat}\sim p^{-\delta }$ with δ=(n+1)/2$\delta =(n+1)/2$, where n$n$ is either the maximal number of broken bonds or of dislodged suspended particles. This result shows that the sets of exponents y=1$y=1$ and δ=1/2$\delta =1/2$ or y=2$y=2$ and δ=1$\delta =1$ found in all previous works focusing on systems with this same type of crossover are not universal. Using scaling arguments, we show that the bulk porosity P$P$ of the deposits scales as P∼p^y−δ$P\sim p^{y-\delta }$ for small values of p$p$. This general scaling relation is confirmed by our numerical simulations and explains previous results present in literature.     

Series and Monte Carlo study of high-dimensional Ising models

Ising models in high dimensions are used to compare high-temperature series expansions with Monte Carlo simulations. Simulations of the magnetization on four-, six-, and seven-dimensional hypercubic lattices give consistent values of the critical temperature from both equilibrium and nonequilibrium data ford=6 and 7. We tabulate 15 terms of series expansions for the susceptibility for generald and giveJ/k _B T _c =0.092295 (3) and 0.077706 (2) ford=6 and 7. In contrast to five dimensions, where earlier series found nonanalytic scaling corrections, for d=6 and 7 the leading scaling correction may be analytic inT-T _c . In most cases these expansions gave more accurate results than these simulations.     

Some properties of random Ising models

We consider an Ising model with random magnetic fieldh _i and random nearest-neighbor couplingsJ _ij . The random variablesh _i andJ _ij are independent and identically distributed with a nice enough distribution, e.g., Gaussian. We will prove that (i) at high temperature, infinite volume correlation functions are independent on the boundary conditions and decay exponentially fast with probability 1 and (ii) for any temperature with sufficiently strong magnetic field the correlation functions are again independent on the boundary conditions and decay exponentially fast with probability 1. We also prove that the averaged magnetization of the ground state configuration of the one-dimensional Ising model with random magnetic field is zero, no matter how small is the variance of theh _i .     

仲氢及正氘团簇的量子定域和超流动性研究

本文采用路径积分Monte Carlo (PIMC)方法研究仲氢团簇和正氘团簇的结构和超流体性质.比较仲氢团簇(分子数N≤40)在T=0.4 K,T=1.6 K的临近能量差和超流比例(superfluid fractions),发现仲氢团簇在T=0.4 K时出现"量子熔化"(quantum melting);研究了仲氢团簇的量子定域(quantum localization)和 "量子熔化"的关系,对T=0.4 K时仲氢及正氘团簇的量子定域与超流动性 关键词： 团簇 量子定域 量子熔化 超流比例     

超声喷流Ar团簇生长演化过程及团簇尺寸轴向分布的实验研究

针对特定形式的喷嘴产生的Ar气体团簇,利用瑞利散射法研究了团簇的生长演化过程,测量了不同背压下空间轴向上的团簇尺度,得到了团簇尺寸随轴向距离与背压的关系.实验发现,在20—60 atm（1 atm=1013 kPa）背压范围内,距离喷嘴出口5 mm处,Ar团簇尺度最大. 关键词： 超声喷流 Ar团簇 瑞利散射 团簇尺度     

电制备巨囊泡的方法和机理探索

利用倒置显微镜研究电制备巨囊泡,并分析其形成和成长的动力学机理.由于磷脂头部的电特性,电场对水化的磷脂双层的静电力促使磷脂膜内双层之间分离.在动力学的作用下,双层两叶的不对称受力引发其弯曲、出芽、膨胀、封闭以及相互融合.结果表明,电场参数、干磷脂膜的均匀性、缓冲液以及温度等因素影响巨囊泡的粒径、形状和稳定性.     

电制备巨囊泡的方法和机理探索

利用倒置显微镜研究电制备巨囊泡, 并分析其形成和成长的动力学机理. 由于磷脂头部的电特性, 电场对水化的磷脂双层的静电力促使磷脂膜内双层之间分离. 在动力学的作用下, 双层两叶的不对称受力引发其弯曲、出芽、膨胀、封闭以及相互融合. 结果表明, 电场参数、干磷脂膜的均匀性、缓冲液以及温度等因素影响巨囊泡的粒径、形状和稳定性.     

AgBr和AgI团簇结构的研究

采用遗传算法结合经验势函数,研究了(AgX)n(X=Br,I,n≤15)团簇的可能稳定结构.结果表明(AgBr)n团簇的稳定结构主要以密堆结构为主,(AgI)n团簇的稳定结构主要以四元环和六元环相接的笼状结构为主.反映出(AgBr)n团簇以离子键结合,而(AgI)n团簇中是具有离子性的共价键.(AgBr)n(n=4,6,10)和(AgI)n(n=6,8,11)的结构较为稳定.     

中性及带电钴团簇的密度泛函理论研究

本文采用基于自旋极化的密度泛函理论系统研究了 小尺寸钴团簇的几何结构和电子结构特性。随尺寸的递增,团簇的基态几何结构由一维演变为三维的几何构型。总磁矩随尺寸的增加线性递增,并呈现奇偶交替的现象。从所研究的系统中分离一个Co原子带正电的团簇体系需要的能量相对较大。本文对体系的电子亲和能（EA）以及离化势（IP）也进行了讨论。     

Structural and magnetic properties of CoPt clusters

The geometrical structures, electronic and magnetic properties of Co_n − xPt_x (n=2–13,38,55$n=2\text{–}13,38,55$) alloy clusters have been systematically investigated by using the density functional theory within the generalized gradient approximation (DFT–GGA). It is found that CoPt alloy clusters adopt the structures of corresponding monatomic Co clusters, where Pt atoms localize at the surface sites and tend to bond together forming a Pt exterior shell. The ferromagnetic coupling between atoms is determined in CoPt clusters, and the Co local magnetic moments can be enhanced by the increase of Pt concentration.     

钛团簇的结构及电子亲和势的理论研究

基于密度泛函理论详细地研究了金属钛的小尺寸团簇的稳定结构及电子性质。具体采用的计算方法是B3LYP/CEP-121G。在这项工作中,我们发现计算的电子亲和势的值与实验值符合的很好,但与原先的理论研究有些不同。