共查询到20条相似文献,搜索用时 406 毫秒
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提出一种新颖的基于分形特征和双层光子带隙(PBG)结构的宽阻带低通滤波器. 该滤波器在接地板上刻蚀一阶Sierpinski carpet PBG结构,在顶层微带线与接地板之间增加一层具 有三阶Sierpinski gasket PBG结构的金属层,该金属层经过打通孔与接地板连通. 这种双 层PBG结构的低通滤波器,具有良好的宽阻带特性,且电路尺寸小、结构紧凑. 对比了单层 普通方孔PBG结构的低通滤波器、单层一阶Sierpinski carpet PBG结构的低通滤波器和双层 分形PBG结构低通滤波器的传
关键词:
低通滤波器
双层PBG结构
分形
宽阻带特性 相似文献
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作为一种基本的动力学过程,复杂网络上的随机游走是当前学术界研究的热点问题,其中精确计算带有陷阱的随机游走过程的平均吸收时间(mean trapping time,MTT)是该领域的一个难点.这里的MTT定义为从网络上任意一个节点出发首次到达设定陷阱的平均时间.本文研究了无标度立体Koch网络上带有一个陷阱的随机游走问题,解析计算了陷阱置于网络中度最大的节点这一情形的网络MTT指标.通过重正化群方法,利用网络递归生成的模式,给出了立体Koch网络上MTT的精确解,所得计算结果与数值解一致,并且从所得结果可以看出,立体Koch网络的MTT随着网络节点数N呈线性增长.最后,将所得结果与之前研究的完全图、规则网络、Sierpinski网络和T分形网络进行比较,结果表明Koch网络具有较高的传输效率. 相似文献
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Tom Kennedy 《Journal of statistical physics》2004,114(1-2):51-78
Simulations of the two-dimensional self-avoiding walk (SAW) are performed in a half-plane and a cut-plane (the complex plane with the positive real axis removed) using the pivot algorithm. We test the conjecture of Lawler, Schramm, and Werner that the scaling limit of the two-dimensional SAW is given by Schramm's stochastic Loewner evolution (SLE). The agreement is found to be excellent. The simulations also test the conformal invariance of the SAW since conformal invariance implies that if we map infinite length walks in the cut-plane into the half plane using the conformal map $z \to \sqrt z$ , then the resulting walks will have the same distribution as the SAW in the half plane. The simulations show excellent agreement between the distributions. 相似文献
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Tom Kennedy 《Journal of statistical physics》2012,146(2):281-293
We conjecture a relationship between the scaling limit of the fixed-length ensemble of self-avoiding walks in the upper half
plane and radial SLE8/3 in this half plane from 0 to i. The relationship is that if we take a curve from the fixed-length scaling limit of the SAW, weight it by a suitable power
of the distance to the endpoint of the curve and apply the conformal map of the half plane that takes the endpoint to i, then we get the same probability measure on curves as radial SLE8/3. In addition to a non-rigorous derivation of this conjecture, we support it with Monte Carlo simulations of the SAW. Using
the conjectured relationship between the SAW and radial SLE8/3, our simulations give estimates for both the interior and boundary scaling exponents. The values we obtain are within a few
hundredths of a percent of the conjectured values. 相似文献
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We study a model for the backbone of proteins on a square lattice which consists of the path traced out by a self-avoiding walk (SAW) on the lattice and bridges not belonging to sites on the SAW but connecting nearest neighbor sites of the SAW. We calculated the fractal dimensiond
w for random walk on this model and found thatd
w2.6, in disagreement with a recent suggestion thatd
w should be 2. 相似文献
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Kennedy T 《Physical review letters》2002,88(13):130601
The conjecture that the scaling limit of the two-dimensional self-avoiding walk (SAW) in a half plane is given by the stochastic Loewner evolution (SLE) with kappa = 8/3 leads to explicit predictions about the SAW. A remarkable feature of these predictions is that they yield not just critical exponents but also probability distributions for certain random variables associated with the self-avoiding walk. We test two of these predictions with Monte Carlo simulations and find excellent agreement, thus providing numerical support to the conjecture that the scaling limit of the SAW is SLE(8/3). 相似文献
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The concept of fractal dimensionality is used to study different statistical methods for generating self-avoiding walks (SAWs). The reliability of SAWs traced by the enrichment technique and the dynamic Monte Carlo technique is verified. The number of dynamic cycles which represent a single independent SAW ofN 0 steps is found to be about 0.1N 0 3 . We show that the enrichment process for generating SAWs may be presented as a critical phenomenon. 相似文献
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Bikas K. Chakrabarti 《Physica A》2007,384(1):25-27
We will utilise the self-avoiding walk (SAW) mapping of the vortex line conformations in turbulence to get the Kolmogorov scale dependence of energy dispersion from SAW statistics, and the knowledge of the effects of disordered fractal geometries on the SAW statistics. These will give us the Kolmogorov energy dispersion exponent value for turbulence in porous media in terms of the size exponent for polymers in the same. We argue that the exponent value will be somewhat less than for turbulence in porous media. 相似文献
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We prove that self-avoiding walk on ${\mathbb{Z}^d}$ is sub-ballistic in any dimension d ≥ 2. That is, writing ${\| u \|}$ for the Euclidean norm of ${u \in \mathbb{Z}^d}$ , and ${\mathsf{P_{SAW}}_n}$ for the uniform measure on self-avoiding walks ${\gamma : \{0, \ldots, n\} \to \mathbb{Z}^d}$ for which γ 0 = 0, we show that, for each v > 0, there exists ${\varepsilon > 0}$ such that, for each ${n \in \mathbb{N}, \mathsf{P_{SAW}}_n \big( {\rm max}\big\{\| \gamma_k \| : 0 \leq k \leq n\big\} \geq vn \big) \leq e^{-\varepsilon n}}$ . 相似文献
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Marco Gherardi 《Journal of statistical physics》2009,136(5):864-874
We numerically test the correspondence between the scaling limit of self-avoiding walks (SAW) in the plane and Schramm-Loewner
evolution (SLE) with κ=8/3. We introduce a discrete-time process approximating SLE in the exterior of a small disc and compare the distribution
functions for an internal point in the SAW and a point at a fixed fractal variation on the SLE, finding good agreement. This
provides numerical evidence in favor of a conjecture by Lawler, Schramm and Werner. The algorithm turns out to be an efficient
way of computing the position of an internal point in the SAW. 相似文献
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H. J. Hilhorst 《Journal of statistical physics》1977,17(6):413-427
We study by real-space renormalization a class of one-dimensional self-avoiding walks (SAWs) exhibiting a nonzero critical temperature. A linear renormalization transformation is carried out in closed form in a three-parameter subspace of SAW Hamiltonians. We find lines of fixed points along which the degree of localization of the fixed-point interactions varies. The role of the spin rescaling factor in the transformation is explicitly demonstrated. 相似文献
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Motivated by Kesten’s bridge decomposition for two-dimensional self-avoiding walks in the upper half plane, we show that the conjectured scaling limit of the half-plane SAW, the SLE(8/3) process, also has an appropriately defined bridge decomposition. This continuum decomposition turns out to entirely be a consequence of the restriction property of SLE(8/3), and as a result can be generalized to the wider class of restriction measures. Specifically we show that the restriction hulls with index less than one can be decomposed into a Poisson Point Process of irreducible bridges in a way that is similar to Itô’s excursion decomposition of a Brownian motion according to its zeros. 相似文献