首页 > 最新文献

Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences最新文献

英文 中文
Three-dimensional separated flow structure over prolate spheroids 长形球体上的三维分离流结构
K. Wang, H. Zhou, C. H. Hû, S. Harrington
Colour poster paints were used for water-tunnel visualization of the surface flow patterns over prolate spheroids of axis-ratios b/a = ½, ⅓ and ¼ at incidence from 0-90°. Results display the surface flow pattern over the entire body presumably for the first time in terms of completeness and clarify unsettled questions in the literature.
在0-90°的入射范围内,使用彩色海报涂料对轴比为b/a = 1 / 2、1 / 3和1 / 4的长形球体的表面流动模式进行水洞可视化。结果显示了整个身体的表面流动模式,可能是第一次在完整性和澄清未解决的问题,在文献中。
{"title":"Three-dimensional separated flow structure over prolate spheroids","authors":"K. Wang, H. Zhou, C. H. Hû, S. Harrington","doi":"10.1098/rspa.1990.0052","DOIUrl":"https://doi.org/10.1098/rspa.1990.0052","url":null,"abstract":"Colour poster paints were used for water-tunnel visualization of the surface flow patterns over prolate spheroids of axis-ratios b/a = ½, ⅓ and ¼ at incidence from 0-90°. Results display the surface flow pattern over the entire body presumably for the first time in terms of completeness and clarify unsettled questions in the literature.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"43 1","pages":"73 - 90"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86136257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 34
Tension-field theory 张力场理论
D. Steigmann
A general theory of the tension field is developed for application to the analysis of wrinkling in isotropic elastic membranes undergoing finite deformations. The principal contribution is a partial differential equation describing a geometrical property of tension trajectories. This is one of a system of two equations which describes the state of stress independently of the deformation. This system is strongly elliptic at any stable solution, whereas the deformation is described by a system of parabolic type. Controllable solutions, i. e. those states that can be maintained in any isotropic elastic material by application of edge tractions and lateral pressure alone, are obtained. The general axisymmetric problem is solved implicitly and the theory is applied to the solution of two representative examples. Existing small strain theories are shown to correspond to a singular limit of the general theory, at which the underlying system changes from elliptic to parabolic type.
提出了一种用于分析各向同性弹性膜在有限变形下起皱的一般张力场理论。主要贡献是一个描述张力轨迹几何性质的偏微分方程。这是一个由两个方程组成的系统之一,它描述了与变形无关的应力状态。该系统在任何稳定解下都是强椭圆型的,而变形则用抛物线型系统来描述。得到了可控解,即在任何各向同性弹性材料中,仅通过施加边缘牵引力和侧压力就能保持的状态。对一般轴对称问题进行了隐式求解,并将该理论应用于两个典型实例的求解。现有的小应变理论对应于一般理论的奇异极限,在此极限下底层系统由椭圆型变为抛物线型。
{"title":"Tension-field theory","authors":"D. Steigmann","doi":"10.1098/rspa.1990.0055","DOIUrl":"https://doi.org/10.1098/rspa.1990.0055","url":null,"abstract":"A general theory of the tension field is developed for application to the analysis of wrinkling in isotropic elastic membranes undergoing finite deformations. The principal contribution is a partial differential equation describing a geometrical property of tension trajectories. This is one of a system of two equations which describes the state of stress independently of the deformation. This system is strongly elliptic at any stable solution, whereas the deformation is described by a system of parabolic type. Controllable solutions, i. e. those states that can be maintained in any isotropic elastic material by application of edge tractions and lateral pressure alone, are obtained. The general axisymmetric problem is solved implicitly and the theory is applied to the solution of two representative examples. Existing small strain theories are shown to correspond to a singular limit of the general theory, at which the underlying system changes from elliptic to parabolic type.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"48 1","pages":"141 - 173"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85218049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 309
A mode III crack at the interface between two nonlinear materials 两种非线性材料界面处的III型裂纹
C. Champion, C. Atkinson
The stress singularity at the tip of a crack at the interface between two different power-law materials under mode III loading (longitudinal shear) is considered. By considering expansions at the crack tip in each region, and matching across the interface ahead of the crack, it is found that the stress singularities are the same in each material, and correspond to that for a crack in a homogeneous material with hardening exponent equal to the maximum of the hardening exponents of the two materials. The displacements near the crack tip are found to be of different orders in the two materials, and it is shown that all the crack tip energy is concentrated in the material with the largest hardening exponent. The results are illustrated by means of an example involving a displacement loaded bimaterial strip.
考虑了两种幂律材料界面在III型载荷(纵向剪切)作用下裂纹尖端的应力奇异性。通过考虑裂纹尖端在各区域的扩展,并在裂纹前方的界面上进行匹配,发现每种材料的应力奇点是相同的,并且对应于硬化指数等于两种材料硬化指数最大值的均匀材料裂纹的应力奇点。两种材料在裂纹尖端附近的位移量级不同,表明裂纹尖端能量全部集中在硬化指数最大的材料中。结果通过一个涉及位移加载双材料条的例子加以说明。
{"title":"A mode III crack at the interface between two nonlinear materials","authors":"C. Champion, C. Atkinson","doi":"10.1098/rspa.1990.0059","DOIUrl":"https://doi.org/10.1098/rspa.1990.0059","url":null,"abstract":"The stress singularity at the tip of a crack at the interface between two different power-law materials under mode III loading (longitudinal shear) is considered. By considering expansions at the crack tip in each region, and matching across the interface ahead of the crack, it is found that the stress singularities are the same in each material, and correspond to that for a crack in a homogeneous material with hardening exponent equal to the maximum of the hardening exponents of the two materials. The displacements near the crack tip are found to be of different orders in the two materials, and it is shown that all the crack tip energy is concentrated in the material with the largest hardening exponent. The results are illustrated by means of an example involving a displacement loaded bimaterial strip.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"162 1","pages":"247 - 257"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73474397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 25
Obstacle drag in stratified flow 分层流中的障碍阻力
I. Castro, W. Snyder, P. Baines
This paper describes an experimental study of the drag of two- and three-dimensional bluff obstacles of various cross-stream shapes when towed through a fluid having a stable, linear density gradient with Brunt-Vaisala frequency, N. Drag measurements were made directly using a force balance, and effects of obstacle blockage (h/D, where h and D are the obstacle height and the fluid depth, respectively) and Reynolds number were effectively eliminated. It is shown that even in cases where the downstream lee waves and propagating columnar waves are of large amplitude, the variation of drag with the parameter K ( = ND/πU) is qualitatively close to that implied by linear theories, with drag minima existing at integral values of K. Under certain conditions large, steady, periodic variations in drag occur. Simultaneous drag measurements and video recordings of the wakes show that this unsteadiness is linked directly with time-variations in the lee and columnar wave amplitudes. It is argued that there are, therefore, situations where the inviscid flow is always unsteady even for large times; the consequent implications for atmospheric motions are discussed.
本文通过实验研究了不同横流形状的二维和三维钝面障碍物在拖曳通过具有稳定的线性密度梯度(Brunt-Vaisala频率为n)的流体时的阻力。阻力测量直接使用力天平进行,有效地消除了障碍物阻塞(h/D,其中h和D分别为障碍物高度和流体深度)和雷诺数的影响。结果表明,即使在下游背风波和传播柱状波振幅较大的情况下,阻力随参数K (= ND/πU)的变化也定性地接近于线性理论所暗示的变化,阻力极小值存在于K的积分值处。在一定条件下,阻力会出现较大的、稳定的周期性变化。同时进行的阻力测量和尾迹的视频记录表明,这种不稳定性与背风波和柱状波振幅的时间变化直接相关。因此,有人认为,在某些情况下,即使在很长时间内,无粘流也总是不稳定的;讨论了由此产生的对大气运动的影响。
{"title":"Obstacle drag in stratified flow","authors":"I. Castro, W. Snyder, P. Baines","doi":"10.1098/rspa.1990.0054","DOIUrl":"https://doi.org/10.1098/rspa.1990.0054","url":null,"abstract":"This paper describes an experimental study of the drag of two- and three-dimensional bluff obstacles of various cross-stream shapes when towed through a fluid having a stable, linear density gradient with Brunt-Vaisala frequency, N. Drag measurements were made directly using a force balance, and effects of obstacle blockage (h/D, where h and D are the obstacle height and the fluid depth, respectively) and Reynolds number were effectively eliminated. It is shown that even in cases where the downstream lee waves and propagating columnar waves are of large amplitude, the variation of drag with the parameter K ( = ND/πU) is qualitatively close to that implied by linear theories, with drag minima existing at integral values of K. Under certain conditions large, steady, periodic variations in drag occur. Simultaneous drag measurements and video recordings of the wakes show that this unsteadiness is linked directly with time-variations in the lee and columnar wave amplitudes. It is argued that there are, therefore, situations where the inviscid flow is always unsteady even for large times; the consequent implications for atmospheric motions are discussed.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"1997 1","pages":"119 - 140"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86243591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 41
Hydrogenolysis and related reactions of hydrocarbons (C3 to C5) on silica-supported Rh-Pt bimetallic catalysts 硅负载铑铂双金属催化剂上碳氢化合物(C3 ~ C5)的氢解及相关反应
J. A. Oliver, C. Kemball
The reactions with hydrogen of propane, butane, 2-methylpropane, pentane, 2-methylbutane, 2, 2-dimethylpropane and cyclopentane have been studied in a static reactor using a series of highly dispersed rhodium-platinum catalysts supported on high-area silica. The main reaction over all catalysts was hydrogenolysis involving the breaking of a single carbon-carbon bond. Most of the compounds reacted at similar rates over platinum with activation energies in the range 132-144 kJ mol-1. With rhodium, rates varied with hydrocarbon structure by factors of more than 102. The selectivities for the formation of the various products showed that the relative rates of breaking different carbon-carbon bonds over rhodium were S-S > P-S > S-T > P-T > P-Q (P = primary, Q = quaternary, S = secondary and T = tertiary). At temperatures above 455 K, there was evidence of a change of rate-determining step over rhodium with the overall reaction becoming controlled by the rate of desorption of methane. Probable mechanisms over platinum and rhodium are discussed. Rhodium was more active than platinum by factors of about 200 for branched hydrocarbons and of 103 or more for straight-chain compounds. Patterns of activity with metal composition are interpreted in terms of active sites consisting of ensembles of about six metal atoms. But an alternative description of the active site as a single metal atom with properties influenced by a number of nearest neighbours cannot be excluded.
采用高面积二氧化硅负载的高分散铑-铂催化剂,在静态反应器中研究了丙烷、丁烷、2-甲基丙烷、戊烷、2-甲基丁烷、2,2 -二甲基丙烷和环戊烷与氢的反应。所有催化剂的主要反应是氢解反应,包括破坏单个碳-碳键。大多数化合物在铂上的反应速率相似,活化能在132-144 kJ mol-1之间。对于铑,反应速率随碳氢化合物结构的不同而变化,影响因子大于102。不同产物形成的选择性表明,铑上不同碳碳键断裂的相对速率为S-S > P-S > S-T > P-T > P-Q (P =一级,Q =四级,S =二级,T =三级)。在455 K以上的温度下,有证据表明铑的速率决定步骤发生了变化,整个反应由甲烷的解吸速率控制。讨论了铂和铑的可能机理。对于支链烃,铑的活性比铂高约200倍,对于直链化合物,铑的活性比铂高103倍或更多。具有金属成分的活性模式是根据由大约6个金属原子组成的系综组成的活性位点来解释的。但是,不能排除将活性位点描述为单个金属原子,其性质受若干近邻的影响。
{"title":"Hydrogenolysis and related reactions of hydrocarbons (C3 to C5) on silica-supported Rh-Pt bimetallic catalysts","authors":"J. A. Oliver, C. Kemball","doi":"10.1098/rspa.1990.0049","DOIUrl":"https://doi.org/10.1098/rspa.1990.0049","url":null,"abstract":"The reactions with hydrogen of propane, butane, 2-methylpropane, pentane, 2-methylbutane, 2, 2-dimethylpropane and cyclopentane have been studied in a static reactor using a series of highly dispersed rhodium-platinum catalysts supported on high-area silica. The main reaction over all catalysts was hydrogenolysis involving the breaking of a single carbon-carbon bond. Most of the compounds reacted at similar rates over platinum with activation energies in the range 132-144 kJ mol-1. With rhodium, rates varied with hydrocarbon structure by factors of more than 102. The selectivities for the formation of the various products showed that the relative rates of breaking different carbon-carbon bonds over rhodium were S-S > P-S > S-T > P-T > P-Q (P = primary, Q = quaternary, S = secondary and T = tertiary). At temperatures above 455 K, there was evidence of a change of rate-determining step over rhodium with the overall reaction becoming controlled by the rate of desorption of methane. Probable mechanisms over platinum and rhodium are discussed. Rhodium was more active than platinum by factors of about 200 for branched hydrocarbons and of 103 or more for straight-chain compounds. Patterns of activity with metal composition are interpreted in terms of active sites consisting of ensembles of about six metal atoms. But an alternative description of the active site as a single metal atom with properties influenced by a number of nearest neighbours cannot be excluded.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"66 1","pages":"17 - 43"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89727570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
On the interpretation of electron diffraction patterns from materials containing planar boundaries: the intergrowth tungsten bronzes 含平面边界材料的电子衍射图解释:共生钨青铜
G. Harburn, R. Tilley, R. Williams
Materials containing planar boundaries are of general interest and complete understanding of their structures is important. When direct imaging of the boundaries by, for instance, high-resolution electron microscopy, is impracticable, details of their structure and arrangement may be obtained from electron diffraction patterns. Such patterns are discussed in terms of those from intergrowth tungsten bronzes as specific examples. Fourier-transform calculations for proposed structures have been made to establish, in conjunction with optical-diffraction analogues, the features of the far-field diffraction patterns. These results have been compared with diffraction patterns obtained experimentally by transmission electron microscopy. The aim of the study, to show that the arrangement of the boundaries in these complicated phases can be deduced from their diffraction patterns without the need for high-resolution imaging, has been achieved. The steps to be taken to make these deductions are set out.
包含平面边界的材料是人们普遍感兴趣的,对其结构的全面理解是很重要的。当直接成像的边界,例如,高分辨率的电子显微镜,是不可行的,他们的结构和安排的细节可以从电子衍射图获得。并以共生钨青铜的纹样为例进行了讨论。对所提出的结构进行了傅里叶变换计算,并结合光学衍射类似物,建立了远场衍射图案的特征。这些结果与透射电镜实验得到的衍射图进行了比较。研究的目的是表明,这些复杂相的边界排列可以从它们的衍射图样中推断出来,而不需要高分辨率的成像,已经实现了。列出了进行这些扣减所应采取的步骤。
{"title":"On the interpretation of electron diffraction patterns from materials containing planar boundaries: the intergrowth tungsten bronzes","authors":"G. Harburn, R. Tilley, R. Williams","doi":"10.1098/rspa.1990.0053","DOIUrl":"https://doi.org/10.1098/rspa.1990.0053","url":null,"abstract":"Materials containing planar boundaries are of general interest and complete understanding of their structures is important. When direct imaging of the boundaries by, for instance, high-resolution electron microscopy, is impracticable, details of their structure and arrangement may be obtained from electron diffraction patterns. Such patterns are discussed in terms of those from intergrowth tungsten bronzes as specific examples. Fourier-transform calculations for proposed structures have been made to establish, in conjunction with optical-diffraction analogues, the features of the far-field diffraction patterns. These results have been compared with diffraction patterns obtained experimentally by transmission electron microscopy. The aim of the study, to show that the arrangement of the boundaries in these complicated phases can be deduced from their diffraction patterns without the need for high-resolution imaging, has been achieved. The steps to be taken to make these deductions are set out.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"1 1","pages":"117 - 91"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89739664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Stieltjes transforms and the Stokes phenomenon Stieltjes变换和Stokes现象
W. Boyd
Recently, Berry, Olver and Jones have found uniform asymptotic expansions for the exponentially small remainder terms that result when asymptotic expansions are optimally truncated. These uniform expansions describe the rapid change in the behaviour of the remainders as a Stokes line is crossed. We show how such uniform expansions may be found when a function can be expressed as a Stieltjes transform. Such an approach has the following advantages: the uniform expansion is calculated directly, non-uniform expansions away from the Stokes line are readily found, and explicit error bounds may be established. We illustrate the method by application to the modified Bessel function Kv(z).
最近,Berry, Olver和Jones发现了指数小剩余项的一致渐近展开式,当渐近展开式被最优截断时产生。这些均匀的膨胀描述了当斯托克斯线被越过时,剩余物行为的快速变化。当一个函数可以用Stieltjes变换表示时,我们将展示如何找到这样的一致展开。这种方法的优点是:直接计算均匀展开,容易找到远离Stokes线的非均匀展开,并且可以建立明确的误差界限。我们通过对修正贝塞尔函数Kv(z)的应用来说明该方法。
{"title":"Stieltjes transforms and the Stokes phenomenon","authors":"W. Boyd","doi":"10.1098/rspa.1990.0058","DOIUrl":"https://doi.org/10.1098/rspa.1990.0058","url":null,"abstract":"Recently, Berry, Olver and Jones have found uniform asymptotic expansions for the exponentially small remainder terms that result when asymptotic expansions are optimally truncated. These uniform expansions describe the rapid change in the behaviour of the remainders as a Stokes line is crossed. We show how such uniform expansions may be found when a function can be expressed as a Stieltjes transform. Such an approach has the following advantages: the uniform expansion is calculated directly, non-uniform expansions away from the Stokes line are readily found, and explicit error bounds may be established. We illustrate the method by application to the modified Bessel function Kv(z).","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"9 1","pages":"227 - 246"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79813568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 42
Deformation and microstructure of rutile 金红石的变形与显微组织
M. Blanchin, L. Bursill, C. Lafage
Studies of the mechanical properties of rutiles are described, in particular the behaviour of the elastic limit under compression with respect to variations in temperature (pure rutile), intrinsic non-stoichiometry (pure rutile reduced under low oxygen pressure) and extrinsic non-stoichiometry (rutile doped with chromia and alumina). A wide range of values is obtained, which may be understood in terms of the interaction of dislocations belonging to the slip systems {101} <1̄01> and {110} <001> with impurities, non-stoichiometric small and extended defects and precipitates. Transmission electron microscopy at medium resolution as well as high-resolution electron microscopy have been used to relate mechanical behaviour with microstructure.
对金红石的力学性能进行了研究,特别是在温度变化(纯金红石)、内在非化学计量(低氧压下还原的纯金红石)和外在非化学计量(掺杂铬和氧化铝的金红石)下压缩弹性极限的行为。得到的数值范围很广,这可以通过属于{101}和{110}滑移系统的位错与杂质、非化学计量的小而扩展的缺陷和沉淀的相互作用来理解。中分辨率透射电子显微镜和高分辨率电子显微镜已被用于将力学行为与微观结构联系起来。
{"title":"Deformation and microstructure of rutile","authors":"M. Blanchin, L. Bursill, C. Lafage","doi":"10.1098/rspa.1990.0056","DOIUrl":"https://doi.org/10.1098/rspa.1990.0056","url":null,"abstract":"Studies of the mechanical properties of rutiles are described, in particular the behaviour of the elastic limit under compression with respect to variations in temperature (pure rutile), intrinsic non-stoichiometry (pure rutile reduced under low oxygen pressure) and extrinsic non-stoichiometry (rutile doped with chromia and alumina). A wide range of values is obtained, which may be understood in terms of the interaction of dislocations belonging to the slip systems {101} <1̄01> and {110} <001> with impurities, non-stoichiometric small and extended defects and precipitates. Transmission electron microscopy at medium resolution as well as high-resolution electron microscopy have been used to relate mechanical behaviour with microstructure.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"8 1","pages":"175 - 202"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81887357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 17
The antiphon. II. The exact evaluation of memory capacity 轮流吟唱的歌。2记忆容量的精确评估
P. Whittle
An improved analysis is given of the antiphon: the device proposed in Whittle (1989) to achieve reliable memory from unreliable components. It is shown that for large systems of N such components one can reliably store KN + o(N) nats of information, and the supremum value of K (the capacity, C) is determined. It is moreover shown that a positive capacity (which is evaluated) can be achieved with the number M of processing units of no more than order N.
一种改进的分析给出了对唱机:装置提出在惠特尔(1989)实现可靠的记忆从不可靠的组件。结果表明,对于有N个这样的组件的大系统,可以可靠地存储KN + o(N) nats的信息,并确定了K(容量C)的最大值。进一步证明,当处理单元的数量M不大于N阶时,可以实现正容量(评估)。
{"title":"The antiphon. II. The exact evaluation of memory capacity","authors":"P. Whittle","doi":"10.1098/rspa.1990.0050","DOIUrl":"https://doi.org/10.1098/rspa.1990.0050","url":null,"abstract":"An improved analysis is given of the antiphon: the device proposed in Whittle (1989) to achieve reliable memory from unreliable components. It is shown that for large systems of N such components one can reliably store KN + o(N) nats of information, and the supremum value of K (the capacity, C) is determined. It is moreover shown that a positive capacity (which is evaluated) can be achieved with the number M of processing units of no more than order N.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"363 1","pages":"45 - 60"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76529779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Scattering by a surface inhomogeneity on an elastic half-space, with application to fluid-structure interaction noise 弹性半空间表面非均匀性散射,并应用于流固相互作用噪声
M. S. Howe
A harmonic point source is situated in fluid bounded by a nominally plane interface with an elastic half-space. The source is close to a small protrusion of the elastic medium into the fluid, and it is required to determine the interaction (‘diffraction’) radiation, i. e. the acoustic, elastic-body and surface (Scholte) waves produced by the scattering of the near field of the source by the protrusion. The solution of this canonical problem is applied to the prediction of acoustic and structural noise generated by low Mach number turbulent flow over an inhomogeneity on the boundary of an elastic solid. Estimates are presented of the frequency spectra of the power delivered to the various wave modes and their dependence on the elastic properties of the solid, and a comparison is made with empirical predictions of excitation of the same modes in the absence of the inhomogeneity. The scattered radiation can be significant even when the surface inhomogeneity does not penetrate beyond the viscous sublayer into the turbulent flow.
谐波点源位于具有弹性半空间的名义平面界面的流体中。源靠近弹性介质进入流体的一个小突起,需要确定相互作用(“衍射”)辐射,即源的近场被突起散射产生的声波、弹性体和表面(Scholte)波。将该典型问题的解应用于弹性固体边界非均匀性上的低马赫数湍流所产生的声噪声和结构噪声的预测。给出了传递到各种波模式的功率的频谱及其对固体弹性特性的依赖的估计,并与没有非均匀性的相同模式的激励的经验预测进行了比较。即使表面不均匀性没有穿透到粘性亚层以外的湍流中,散射辐射也可能是显著的。
{"title":"Scattering by a surface inhomogeneity on an elastic half-space, with application to fluid-structure interaction noise","authors":"M. S. Howe","doi":"10.1098/rspa.1990.0057","DOIUrl":"https://doi.org/10.1098/rspa.1990.0057","url":null,"abstract":"A harmonic point source is situated in fluid bounded by a nominally plane interface with an elastic half-space. The source is close to a small protrusion of the elastic medium into the fluid, and it is required to determine the interaction (‘diffraction’) radiation, i. e. the acoustic, elastic-body and surface (Scholte) waves produced by the scattering of the near field of the source by the protrusion. The solution of this canonical problem is applied to the prediction of acoustic and structural noise generated by low Mach number turbulent flow over an inhomogeneity on the boundary of an elastic solid. Estimates are presented of the frequency spectra of the power delivered to the various wave modes and their dependence on the elastic properties of the solid, and a comparison is made with empirical predictions of excitation of the same modes in the absence of the inhomogeneity. The scattered radiation can be significant even when the surface inhomogeneity does not penetrate beyond the viscous sublayer into the turbulent flow.","PeriodicalId":20605,"journal":{"name":"Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences","volume":"137 1","pages":"203 - 226"},"PeriodicalIF":0.0,"publicationDate":"1990-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80090534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
期刊
Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1