scaling law

缩放定律
  • 文章类型: Journal Article
    神经肌肉接头(NMJ)具有精细的解剖结构,以确保敏捷和准确的信号传输。根据我们以前获得的热和电导感应电压波动的表达式,在本文中,电导引起的电压波动的潜在机制从两个方面进行表征:关于两个系统尺寸因素中的任何一个的缩放定律,受体的数量或膜面积;以及关于密集参数的“跷跷板效应”,乙酰胆碱的浓度。根据这些机制,从去噪的角度解释了NMJ解剖学的几个方面。最后,这两种类型的电压波动的功率谱的特点是他们的特定的缩放定律,在此基础上,我们解释了为什么端板噪声具有术语“贝壳声音”所描述的低频特性。
    The neuromuscular junction (NMJ) has an elaborate anatomy to ensure agile and accurate signal transmission. Based on our formerly obtained expressions of the thermal and conductance induced voltage fluctuations, in this paper, the mechanisms underlying the conductance-induced voltage fluctuation are characterized from two aspects: the scaling laws with respect to either of the two system-size factors, the number of receptors or the membrane area; and the \"seesaw effect\" with respect to the intensive parameter, the concentration of acetylcholine. According to these mechanisms, several aspects of the NMJ anatomy are explained from a denoising perspective. Finally, the power spectra of the two types of voltage fluctuations are characterized by their specific scaling laws, based on which we explain why the endplate noise has the low-frequency property that is described by the term \"seashell sound\".
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  • 文章类型: Journal Article
    实现冷凝液滴以最小尺寸从固体表面的跳跃分离对于诸如防雾/结霜和传热的应用至关重要。例如,如果液滴以小于400-720nm可见光波长的尺寸均匀跳跃,防雾问题可以解决。相比之下,迄今为止,通过实验观察到的均匀跳跃的最小液滴半径约为16μm。这里,我们显示了在超疏水薄壁晶格(TWL)纳米结构上与超亲水纳米点集成的均匀半径低至3.6nm的持续液滴跳跃的分子动力学(MD)模拟。尺寸截止归因于岛液滴的优先交叉晶格聚结。作为一个应用程序,MD结果显示传热系数(HTC)提高了10倍,显示最大液滴半径的-1缩放定律。我们提供了跳跃和润湿行为的相图,以指导具有高级防露性能的晶格结构的设计。
    Realizing jumping detachment of condensed droplets from solid surfaces at the smallest sizes possible is vital for applications such as antifogging/frosting and heat transfer. For instance, if droplets uniformly jump at sizes smaller than visible light wavelengths of 400-720 nm, antifogging issues could be resolved. In comparison, the smallest droplets experimentally observed so far to jump uniformly were around 16 μm in radius. Here, we show molecular dynamics (MD) simulations of persistent droplet jumping with a uniform radius down to only 3.6 nm on superhydrophobic thin-walled lattice (TWL) nanostructures integrated with superhydrophilic nanospots. The size cutoff is attributed to the preferential cross-lattice coalescence of island droplets. As an application, the MD results exhibit a 10× boost in the heat transfer coefficient (HTC), showing a -1 scaling law with the maximum droplet radius. We provide phase diagrams for jumping and wetting behaviors to guide the design of lattice structures with advanced antidew performance.
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  • 文章类型: Journal Article
    在一个生态系统中,自然和人类过程导致的环境变化会导致系统的一些关键参数随时间而变化。根据这样的参数变化的速度,可能会出现临界点。现有的费率诱发倾翻工程,或者翻倒,提供了一种理论方法来研究这种现象,但从局部动力学的角度来看,揭示,例如,对于某些特定的初始条件,存在临界速率,高于该临界速率将出现临界点。由于生态系统不断受到干扰,并可能偏离平衡点,有必要从整个相关相空间区域的初始条件的全局角度研究R-倾向性。特别是,我们介绍了从整个相关相空间中为初始条件定义的R倾翻概率的概念。使用一些现实世界,复杂的互惠网络作为范式,我们在这个概率和参数变化率之间找到了一个尺度定律,并提供了一个几何理论来解释这个定律。现实世界的含义是,即使是缓慢的参数变化也可能导致系统崩溃,并带来灾难性后果。事实上,仅通过减慢参数漂移来减轻环境变化可能并不总是有效的:只有当参数变化的速率降低到实际上为零时,才会避免倾翻。我们的全球动力学方法提供了一种更完整和物理上有意义的方式来理解R-tipping的重要现象。
    In an ecosystem, environmental changes as a result of natural and human processes can cause some key parameters of the system to change with time. Depending on how fast such a parameter changes, a tipping point can occur. Existing works on rate-induced tipping, or R-tipping, offered a theoretical way to study this phenomenon but from a local dynamical point of view, revealing, e.g., the existence of a critical rate for some specific initial condition above which a tipping point will occur. As ecosystems are subject to constant disturbances and can drift away from their equilibrium point, it is necessary to study R-tipping from a global perspective in terms of the initial conditions in the entire relevant phase space region. In particular, we introduce the notion of the probability of R-tipping defined for initial conditions taken from the whole relevant phase space. Using a number of real-world, complex mutualistic networks as a paradigm, we find a scaling law between this probability and the rate of parameter change and provide a geometric theory to explain the law. The real-world implication is that even a slow parameter change can lead to a system collapse with catastrophic consequences. In fact, to mitigate the environmental changes by merely slowing down the parameter drift may not always be effective: Only when the rate of parameter change is reduced to practically zero would the tipping be avoided. Our global dynamics approach offers a more complete and physically meaningful way to understand the important phenomenon of R-tipping.
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  • 文章类型: Journal Article
    梅毒已经引起了数百年的流行,全球梅毒形势依然严峻。浙江省梅毒报告发病率连续多年在法定报告传染病方面居全省首位,为全国之最。本研究试图利用尺度定律理论研究人口规模与不同类型梅毒流行的关系,同时还探讨了影响不同地区梅毒发病的主要驱动因素。
    县级梅毒病例和受影响人群的数据来自中国疾病预防控制信息系统。用比例定律解释了梅毒不同阶段与种群规模之间的比例关系。通过连接点回归检验2016-2022年的发病率趋势。采用模拟与观测指标之间的距离指标(DISO)来评价联合点回归模型的整体性能。此外,采用多变量时间序列模型来确定影响县级梅毒发生的主要驱动因素。小于0.05的P值或置信区间(CI)不包括所有测试的0表示的统计显著性。
    2016年至2022年,浙江省共报告梅毒204719例,包括2人死亡,都是先天性梅毒。潜伏梅毒占梅毒总病例的79.47%。所有类型梅毒的年度变化百分比(APC),包括原发性梅毒,二期梅毒,三级梅毒,先天性梅毒和潜伏梅毒,为-21.70%(p<0.001,95%CI:-26.70至-16.30),-16.80%(p<0.001,95%CI:-20.30至-13.30),-8.70%(p<0.001,95%CI:-11.30至-6.00),-39.00%(p=0.001,95%CI:-49.30至-26.60)和-7.10%(p=0.008,95%CI:-11.20至-2.80),分别。原发性梅毒的综合比例指数,二期梅毒,三级梅毒,基于随机效应模型的先天性梅毒和潜伏梅毒分别为0.95(95%CI:0.88~1.01),1.14(95%CI:1.12至1.16),0.43(95%CI:0.37至0.49),0.0264(95%CI:-0.0047至0.0575)和0.88(95%CI:0.82至0.93),分别。地方性成分的总体平均影响值,各县的时空分量和自回归分量分别为0.24、0.035和0.72。大多数县的自回归分量值大于0.7。最高值排名前10位的县的地方病成分大于0.34。时空分量值大于0.1的两个县分别是西湖景观县和升寺县。2016-2022年各县的地方病成分和自回归成分均呈现明显的季节性变化。
    缩放指数在每种梅毒类型与种群大小之间的关联中既具有时间趋势特征,又具有显着的异质性。原发性梅毒和潜伏梅毒呈线性模式,二期梅毒呈现超线性模式,和三级梅毒表现出亚线性模式。这表明需要进一步预防高危人群中的感染和传播,并提高欠发达地区的诊断准确性。自回归成分和地方性成分是影响梅毒发生的主要驱动因素。必须根据各县疫情的主要驱动模式制定有针对性的防控策略。
    Syphilis has caused epidemics for hundreds of years, and the global syphilis situation remains serious. The reported incidence rate of syphilis in Zhejiang Province has ranked first in the province in terms of notifiable infectious diseases for many years and is the highest in China. This study attempts to use the scaling law theory to study the relationship between population size and different types of syphilis epidemics, while also exploring the main driving factors affecting the incidence of syphilis in different regions.
    Data on syphilis cases and affected populations at the county level were obtained from the China Disease Control and Prevention Information System. The scaling relationship between different stages of syphilis and population size was explained by scaling law. The trend of the incidence from 2016 to 2022 was tested by the joinpoint regression. The index of distance between indices of simulation and observation (DISO) was applied to evaluate the overall performance of joinpoint regression model. Furthermore, a multivariate time series model was employed to identify the main driving components that affected the occurrence of syphilis at the county level. The p value less than 0.05 or confidence interval (CI) does not include 0 represented statistical significance for all the tests.
    From 2016 to 2022, a total of 204,719 cases of syphilis were reported in Zhejiang Province, including 2 deaths, all of which were congenital syphilis. Latent syphilis accounted for 79.47% of total syphilis cases. The annual percent change (APCs) of all types of syphilis, including primary syphilis, secondary syphilis, tertiary syphilis, congenital syphilis and latent syphilis, were - 21.70% (p < 0.001, 95% CI: -26.70 to -16.30), -16.80% (p < 0.001, 95% CI: -20.30 to -13.30), -8.70% (p < 0.001, 95% CI: -11.30 to -6.00), -39.00% (p = 0.001, 95% CI: -49.30 to -26.60) and - 7.10% (p = 0.008, 95% CI: -11.20 to -2.80), respectively. The combined scaling exponents of primary syphilis, secondary syphilis, tertiary syphilis, congenital syphilis and latent syphilis based on the random effects model were 0.95 (95% CI: 0.88 to 1.01), 1.14 (95% CI: 1.12 to 1.16), 0.43 (95% CI: 0.37 to 0.49), 0.0264 (95% CI: -0.0047 to 0.0575) and 0.88 (95% CI: 0.82 to 0.93), respectively. The overall average effect values of the endemic component, spatiotemporal component and autoregressive component for all counties were 0.24, 0.035 and 0.72, respectively. The values of the autoregressive component for most counties were greater than 0.7. The endemic component of the top 10 counties with the highest values was greater than 0.34. Two counties with value of the spatiotemporal component higher than 0.1 were Xihu landscape county and Shengsi county. From 2016 to 2022, the endemic and autoregressive components of each county showed obvious seasonal changes.
    The scaling exponent had both temporal trend characteristics and significant heterogeneity in the association between each type of syphilis and population size. Primary syphilis and latent syphilis exhibited a linear pattern, secondary syphilis presented a superlinear pattern, and tertiary syphilis exhibited a sublinear pattern. This suggested that further prevention of infection and transmission among high-risk populations and improvement of diagnostic accuracy in underdeveloped areas is needed. The autoregressive components and the endemic components were the main driving factors that affected the occurrence of syphilis. Targeted prevention and control strategies must be developed based on the main driving modes of the epidemic in each county.
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  • 文章类型: Journal Article
    嵌段共聚物是一类在有序结构中自组装的能力方面特别令人感兴趣的材料。在这种情况下,考虑到分子水平的运动会影响大分子的各种性质,环境与动力学之间的耦合尤其重要。将聚合物与第二大分子混合似乎是研究这些关系的简单方法。在这项工作中,我们研究了聚(甲基丙烯酸甲酯)(PMMA)和由PMMA作为第一嵌段和聚(3-甲基-4-[6-(甲基丙烯酰氧基)-己氧基]-4'-戊氧基偶氮苯)作为第二嵌段组成的嵌段共聚物的共混物。通过电子自旋共振(ESR)光谱研究了这些共混物的弛豫特性,对纳米长度尺度敏感。对共混物的研究结果与共聚物的动态行为有关。在纳米级,这项研究揭示了异质性的存在,具有可用于分子重新定向的缓慢和快速动力学,其进一步通过嵌段共聚物形成超分子结构的能力来调节。对于混合物,仍然检测到纳米级的异质性。然而,观察到PMMA作为共混物的主要组分的存在改变了其动态行为。
    Block copolymers are a class of materials that are particularly interesting with respect to their capability to self-assemble in ordered structures. In this context, the coupling between environment and dynamics is particularly relevant given that movements at the molecular level influence various properties of macromolecules. Mixing the polymer with a second macromolecule appears to be an easy method for studying these relationships. In this work, we studied blends of poly(methyl methacrylate) (PMMA) and a block copolymer composed of PMMA as the first block and poly(3-methyl-4-[6-(methylacryloyloxy)-hexyloxy]-4\'-pentyloxy azobenzene) as the second block. The relaxational properties of these blends were investigated via electron spin resonance (ESR) spectroscopy, which is sensitive to nanometric length scales. The results of the investigations on the blends were related to the dynamic behavior of the copolymers. At the nanoscale, the study revealed the presence of heterogeneities, with slow and fast dynamics available for molecular reorientation, which are further modulated by the ability of the block copolymers to form supramolecular structures. For blends, the heterogeneities at the nanoscale were still detected. However, it was observed that the presence of the PMMA as a major component of the blends modified their dynamic behavior.
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  • 文章类型: Journal Article
    厚实的植物的高度,比如木本植物,与胸高直径的三分之二成正比。然而,这条规则不能应用于薄而柔软的草本植物,因为支撑它们身体的机制根本不同。本研究旨在阐明草本植物内部水分引起的膨胀压力引起的刚度控制机制,以制定相应的结垢规律。我们将草本植物建模为悬臂,以地面为固定端,考虑到膨胀压力的轴向张力,制定了最大高度。从理论上推导了根据膨胀压力描述高度与直径之间关系的缩放定律。此外,提出了一种基于应力分布的植物分类规则。
    The height of thick and solid plants, such as woody plants, is proportional to two-thirds of the power of their diameter at breast height. However, this rule cannot be applied to herbaceous plants that are thin and soft because the mechanisms supporting their bodies are fundamentally different. This study aims to clarify the rigidity control mechanism resulting from turgor pressure caused by internal water in herbaceous plants to formulate the corresponding scaling law. We modeled a herbaceous plant as a cantilever with the ground side as a fixed end, and the greatest height was formulated considering the axial tension force from the turgor pressure. The scaling law describing the relationship between the height and diameter in terms of the turgor pressure was theoretically derived. Moreover, we proposed a plant classification rule based on stress distribution.
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  • 文章类型: Journal Article
    慢地震的尺度定律,这是地震矩和持续时间之间的线性关系,是在15年前提出的,并发起了一场关于控制缓慢与缓慢的物理过程差异的辩论。快速(普通)地震。根据新的观察,在一个广泛的时期范围内,我们证明慢地震的线性标度仍然有效,但作为~1013Nm/s的力矩速率的明确定义的上限。慢速地震和快速地震的缩放比例之间的力矩率差距仍然没有填补。慢地震发生在可探测阈值附近,这样我们就无法以较低的力矩率检测变形事件。在缓慢地震类别中观察到的趋势支持了这样一种观点,即这个不可观察的领域充满了较低力矩率的事件。这表明观点发生了变化-建议的缩放应被视为一个界限,或速度限制,缓慢的地震我们认为慢地震代表扩散传播,并且定矩率反映了这些扩散过程速度的上限。普通地震,相比之下,发生在地震波传播和断裂之间的耦合过程。因此,即使这两种现象都以剪切滑移的形式出现,缩放的差异反映了控制传播的物理过程的差异。
    The scaling law for slow earthquakes, which is a linear relationship between seismic moment and duration, was proposed 15 y ago and initiated a debate on the difference in physical processes governing slow vs. fast (ordinary) earthquakes. Based on new observations across a wide period range, we show that linear scaling of slow earthquakes remains valid, but as a well-defined upper bound on moment rate of ~1013 Nm/s. The large gap in moment-rate between the scaling of slow and fast earthquakes remains unfilled. Slow earthquakes occur near the detectability threshold, such that we are unable to detect deformation events with lower moment rates. Observed trends within slow earthquake categories support the idea that this unobservable field is populated with events of lower moment rate. This suggests a change in perspective - that the proposed scaling should be considered as a bound, or speed limit, on slow earthquakes. We propose that slow earthquakes represent diffusional propagation, and that the bound on moment rate reflects an upper limit on the speed of those diffusional processes. Ordinary earthquakes, in contrast, occur as a coupled process between seismic wave propagation and fracture. Thus, even though both phenomena occur as shear slip, the difference of scaling reflects a difference in the physical process governing propagation.
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  • 文章类型: Journal Article
    Cu0.5Fe2.5O4纳米粒子是通过自燃方法合成的,其XRD和FTIR分析证实了所需的尖晶石相的形成。传导的热演化显示了由非重叠小极化子隧道(NSPT)模型控制的极化子传输机制解释的半导体行为。直流电导率与跳频呈正相关。电导率的缩放导致单个通用曲线,其中缩放参数α具有正值,这证明了移动粒子之间存在库仑相互作用。传导和弛豫过程与相似的活化能呈正相关。奈奎斯特图的特征是半圆弧,由等效电路(R//C//CPE)完美建模,表明晶粒的贡献。通过麦克斯韦-瓦格纳的现象学理论,介电行为显示出很强的传导优势。电导率和介电损耗的低值和介电常数的高值,使我们的化合物成为储能的有希望的候选者,光催化和微电子应用。
    Cu0.5Fe2.5O4 nanoparticles were synthesized by the self-combustion method whose XRD and FTIR analyzes confirm the formation of the desired spinel phase. The thermal evolution of conduction shows a semiconductor behaviour explained by a polaronic transport mechanism governed by the Non-overlapping Small Polaron Tunnelling (NSPT) model. DC conductivity and hopping frequency are positively correlated. The scaling of the conductivity leads to a single universal curve where the scaling parameter α has positive values, which testifies to the presence of Coulomb interactions between the mobile particles. Conduction and relaxation processes are positively correlated by similar activation energies. Nyquist diagrams are characterized by semicircular arcs perfectly modeled by an equivalent electrical circuit (R//C//CPE) indicating the contribution of the grains. The dielectric behaviour shows a strong predominance of conduction by the phenomenological theory of Maxwell-Wagner. The low values of electrical conductivity and dielectric loss and the high value of permittivity, make our compound a promising candidate for energy storage, photocatalytic and microelectronic applications.
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  • 文章类型: Journal Article
    已经尝试用胶凝剂和聚合物溶液的各种组合通过聚合物溶液和胶凝剂溶液之间的液-液接触进行胶凝。在许多组合中,凝胶生长动力学表示为X~t,其中X是凝胶厚度,t是经过的时间,并且缩放定律适用于X和t之间的关系。在血浆凝胶化过程中,然而,观察到生长行为从早期的X〜t到后期的X〜t的交叉。发现交叉行为是由生长的速率限制过程从自由能限制过程到扩散限制过程的变化引起的。How,然后,我们发现,由于溶胶-凝胶相之间的自由能差导致的特征长度,因此在早期阶段就不存在,但在后期确实如此。我们还根据缩放定律讨论了交叉的分析方法。
    Gelation through the liquid-liquid contact between a polymer solution and a gelator solution has been attempted with various combinations of gelator and polymer solutions. In many combinations, the gel growth dynamics is expressed as X∼t, where X is the gel thickness and t is the elapsed time, and the scaling law holds for the relationship between X and t. In the blood plasma gelation, however, the crossover of the growth behavior from X∼t in the early stage to X∼t in the late stage was observed. It was found that the crossover behavior is caused by a change in the rate-limiting process of growth from the free-energy-limited process to the diffusion-limited process. How, then, would the crossover phenomenon be described in terms of the scaling law? We found that the scaling law does not hold in the early stage owing to the characteristic length attributable to the free energy difference between the sol-gel phases, but it does in the late stage. We also discussed the analysis method for the crossover in terms of the scaling law.
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  • 文章类型: Journal Article
    热磁不稳定性是超导体应用的关键问题。本文系统地研究了边缘裂纹对超导薄膜热磁不稳定性的影响。薄膜中的树枝状通量雪崩通过电动力学模拟得到了很好的再现,并从耗散涡旋动力学模拟中揭示了相关的物理机制。发现边缘裂纹会急剧降低超导薄膜热磁不稳定性的阈值场。频谱分析表明,磁化跳跃的时间序列显示出尺度不变性,并遵循幂律,指数约为1.9。在破裂的电影中,与无裂纹对应物相比,磁通跳跃频率更高,振幅更低。随着裂缝的延伸,阈值场减小,跳跃频率变低,而它的大小越来越大。当裂缝延伸到足够长的时候,阈值场增加到甚至大于无裂纹膜的阈值场。这种违反直觉的结果源于在裂纹尖端触发的热磁不稳定性转变为在裂纹边缘中心触发的热磁不稳定性。磁化跳跃序列的多重分形谱验证了这一点。此外,随着裂纹长度的变化,发现了三种不同的涡旋运动模式,这解释了雪崩过程中形成的不同通量模式。
    Thermomagnetic instability is a crucial issue for the application of superconductors. Effects of edge cracks on the thermomagnetic instability of superconducting thin films are systematically investigated in this work. Dendritic flux avalanches in thin films are well reproduced through electrodynamics simulations, and relevant physical mechanisms are revealed from dissipative vortex dynamics simulations. It is found that edge cracks sharply decrease the threshold field for the thermomagnetic instability of superconducting films. Spectrum analysis shows that the time series of magnetization jumping displays scale-invariance and follows a power law with an exponent around 1.9. In a cracked film, flux jumps more frequently with lower amplitudes compared with its crack-less counterpart. As the crack extends, the threshold field decreases, the jumping frequency gets lower, while its magnitude gets larger. When the crack has extended long enough, the threshold field increases to even larger than that of the crack-less film. This counterintuitive result originates from the transition of the thermomagnetic instability triggered at the crack tip to the one triggered at the center of the crack edges, which is validated by the multifractal spectrum of magnetization jumping sequences. In addition, with the variation of crack lengths, three different modes of vortex motion are found, which explains the different flux patterns formed in the avalanche process.
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