Spatially constrained planar networks are frequently encountered in real-life systems. In this paper, based on a space-filling disk packing we propose a minimal model for spatial maximal planar networks, which is similar to but different from the model for Apollonian networks [J. S. Andrade, Jr. et al., Phys. Rev. Lett. {\bf 94}, 018702 (2005)]. We present an exhaustive analysis of various properties of our model, and obtain the analytic solutions for most of the features, including degree distribution, clustering coefficient, average path length, and degree correlations. The model recovers some striking generic characteristics observed in most real networks. To address the robustness of the relevant network properties, we compare the structural features between the investigated network and the Apollonian networks. We show that topological properties of the two networks are encoded in the way of disk packing. We argue that spatial constrains of nodes are relevant to the structure of the networks.
Marginal stability in jammed packings: quasicontacts and weak contacts
最大随机干扰(MRJ)球包装是一个典型的例子,一个系统自然平衡在欠约束和过约束之间的边缘。这种边缘稳定性传统上被理解为均衡性,机械接触的数量和自由度的数量相等。准接触,即将接触的成对球体,与静态稳定性无关,但当考虑动态稳定性时,它们起作用,接触力的分布也是如此。我们表明,边际动力稳定性的影响,表现在准接触和弱接触的分布,是相应的和非平凡的。我们首先研究这些想法的背景下MRJ包装的d维领域,在那里我们表明,丰富的准接触增长速度比接触。我们重新审视了Jin等人(Phys. Rev. E 82,051126,2010)的计算,其中准接触最初被忽略,我们探讨了它们包含在计算中的影响。这种分析产生了估计的堆积密度在高维的渐近行为。我们认为,这一估计应被重新解释为一个下限。后一部分的文件是专门的布拉维晶格填料,拥有最少的接触,以保持机械稳定性。我们表明,准接触发挥更重要的作用,在这些包装。我们还表明,拥挤的晶格是一个有用的设置研究爱德华兹合奏,每个机械稳定的配置平等的重量,不占动态。该分析未能预测近零接触力$P(f)\sim f^θ$的幂律分布。
Comment on "Mechanical analog of temperature for the description of force distribution in static granular packings"
Ngan [Phys.Rev.E68,011301(2003)]已经提出,颗粒接触力分布可以通过最小化热力学自由能的模拟来解析地导出,在这种情况下,热力学自由能由存储在压缩接触中的总势能减去由参数加权的特定形式的熵组成。该参数被识别为机械温度。我认为,特定形式的熵不能是正确的,因此,所提出的方法产生越来越多的错误的结果,增加粮食刚度。Ngan发表的结果以及其他数值模拟和实验都证明了这一趋势。