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Hyperbolic Fibonacci and Lucas Functions, “Golden” Fibonacci Goniometry, Bodnar’s Geometry, and Hilbert’s Fourth Problem—Part II. A New Geometric Theory of Phyllotaxis (Bodnar’s Geometry) 被引量:2
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作者 Alexey Stakhov Samuil Aranson 《Applied Mathematics》 2011年第2期181-188,共8页
This article refers to the “Mathematics of Harmony” by Alexey Stakhov in 2009, a new interdisciplinary direction of modern science. The main goal of the article is to describe two modern scientific discoveries–New ... This article refers to the “Mathematics of Harmony” by Alexey Stakhov in 2009, a new interdisciplinary direction of modern science. The main goal of the article is to describe two modern scientific discoveries–New Geometric Theory of Phyllotaxis (Bodnar’s Geometry) and Hilbert’s Fourth Problem based on the Hyperbolic Fibonacci and Lucas Functions and “Golden” Fibonacci λ-Goniometry (λ > 0 is a given positive real number). Although these discoveries refer to different areas of science (mathematics and theoretical botany), however they are based on one and the same scientific ideas-the “golden mean,” which had been introduced by Euclid in his Elements, and its generalization—the “metallic means,” which have been studied recently by Argentinian mathematician Vera Spinadel. The article is a confirmation of interdisciplinary character of the “Mathematics of Harmony”, which originates from Euclid’s Elements. 展开更多
关键词 Euclid’s Fifth Postulate Lobachevski’s geometry HYPERBOLIC geometry PHYLLOTAXIs Bodnar’s geometry Hilbert’s Fourth Problem The “Golden” and “Metallic” Means Binet Formukas HYPERBOLIC FIBONACCI and Lucas Functions Gazale Formulas “Golden” FIBONACCI λ-Goniometry
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A Procedure for Trisecting an Acute Angle (Method 2)
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作者 Lyndon O. Barton 《Advances in Pure Mathematics》 2024年第4期204-213,共10页
This paper presents an alternate graphical procedure (Method 2), to that presented in earlier publications entitled, “A Procedure for Trisecting an Acute Angle” and “A Key to Solving the Angle Trisection Problem”.... This paper presents an alternate graphical procedure (Method 2), to that presented in earlier publications entitled, “A Procedure for Trisecting an Acute Angle” and “A Key to Solving the Angle Trisection Problem”. The procedure, when applied to the 30˚ and 60˚ angles that have been “proven” to be nottrisectable and the 45˚ benchmark angle that is known to be trisectable, in each case produced a construction having an identical angular relationship with Archimedes’ Construction, as in Section 2 on THEORY of this paper, where the required trisection angle was found to be one-third of its respective angle (i.e. DE’MA = 1/3 DE’CG). For example, the trisection angle for the 30˚, 45˚ and 60˚ angles were 10.00000˚, 15.00000˚, and 20.00000˚, respectively, and Section 5 on PROOF in this paper. Therefore, based on this identical angular relationship and the numerical results (i.e. to five decimal places), which represent the highest degree of accuracy and precision attainable by The Geometer’s Sketch Pad software, one can only conclude that not only the geometric requirements for arriving at an exact trisection of the 30˚ and 60˚ angle (which have been “proven” to be not-trisectable) have been met, but also, the construction is valid for any arbitrary acute angle, despite theoretical proofs to the contrary by Wantzel, Dudley, and others. 展开更多
关键词 Archimedes Construction College geometry College Mathematics Angle Trisection Famous Problems in Mathematics Mechanism Analysis Geometer’s sketch Pad
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Hyperbolic Fibonacci and Lucas Functions, “Golden” Fibonacci Goniometry, Bodnar’s Geometry, and Hilbert’s Fourth Problem—Part III. An Original Solution of Hilbert’s Fourth Problem 被引量:3
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作者 Alexey Stakhov Samuil Aranson 《Applied Mathematics》 2011年第3期283-293,共11页
This article refers to the “Mathematics of Harmony” by Alexey Stakhov [1], a new interdisciplinary direction of modern science. The main goal of the article is to describe two modern scientific discoveries—New Geom... This article refers to the “Mathematics of Harmony” by Alexey Stakhov [1], a new interdisciplinary direction of modern science. The main goal of the article is to describe two modern scientific discoveries—New Geometric Theory of Phyl-lotaxis (Bodnar’s Geometry) and Hilbert’s Fourth Problem based on the Hyperbolic Fibonacci and Lucas Functions and “Golden” Fibonacci -Goniometry ( is a given positive real number). Although these discoveries refer to different areas of science (mathematics and theoretical botany), however they are based on one and the same scien-tific ideas—The “golden mean,” which had been introduced by Euclid in his Elements, and its generalization—The “metallic means,” which have been studied recently by Argentinian mathematician Vera Spinadel. The article is a confirmation of interdisciplinary character of the “Mathematics of Harmony”, which originates from Euclid’s Elements. 展开更多
关键词 Euclid’s Fifth Postulate Lobachevski’s geometry HYPERBOLIC geometry Phyllotaxis Bodnar’s geometry Hilbert’s FOURTH Problem the “Golden” and “Metallic” Means Binet Formulas HYPERBOLIC FIBONACCI and Lucas Functions Gazale Formulas “Golden” FIBONACCI -Goniometry
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Hyperbolic Fibonacci and Lucas Functions, “Golden” Fibonacci Goniometry, Bodnar’s Geometry, and Hilbert’s——Part I. Hyperbolic Fibonacci and Lucas Functions and “Golden” Fibonacci Goniometry 被引量:1
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作者 Alexey Stakhov Samuil Aranson 《Applied Mathematics》 2011年第1期74-84,共11页
This article refers to the “Mathematics of Harmony” by Alexey Stakhov in 2009, a new interdisciplinary direction of modern science. The main goal of the article is to describe two modern scientific discove-ries—New... This article refers to the “Mathematics of Harmony” by Alexey Stakhov in 2009, a new interdisciplinary direction of modern science. The main goal of the article is to describe two modern scientific discove-ries—New Geometric Theory of Phyllotaxis (Bodnar’s Geometry) and Hilbert’s Fourth Problem based on the Hyperbolic Fibonacci and Lucas Functions and “Golden” Fibonacci λ-Goniometry ( λ > 0 is a given positive real number). Although these discoveries refer to different areas of science (mathematics and theoretical botany), however they are based on one and the same scientific ideas—the “golden mean”, which had been introduced by Euclid in his Elements, and its generalization—the “metallic means”, which have been studied recently by Argentinian mathematician Vera Spinadel. The article is a confirmation of interdisciplinary character of the “Mathematics of Harmony”, which originates from Euclid’s Elements. 展开更多
关键词 Euclid’s Fifth Postulate Lobachevski’s geometry HYPERBOLIC geometry Phyllotaxis Bodnar’s geometry Hilbert’s Fourth Problem The “Golden” and “Metallic” Means Binet Formulas HYPERBOLIC FIBONACCI and Lucas FUNCTIONs Gazale Formulas “Golden” FIBONACCI λ-Goniometry
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<i>CMB</i>—A Geometric, Lorentz Invariant Model in Non-Expanding Lobachevskian Universe with a Black Body Spectral Distribution Function 被引量:1
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作者 J. Georg von Brzeski Vadim von Brzeski 《Journal of Modern Physics》 2017年第13期2104-2121,共18页
In the present paper, based on Lobachevskian (hyperbolic) static geometry, we present (as an alternative to the existing Big Bang model of CMB) a geometric model of CMB in a Lobachevskian static universe as a homogene... In the present paper, based on Lobachevskian (hyperbolic) static geometry, we present (as an alternative to the existing Big Bang model of CMB) a geometric model of CMB in a Lobachevskian static universe as a homogeneous space of horospheres. It is shown that from the point of view of physics, a horosphere is an electromagnetic wavefront in Lobachevskian space. The presented model of CMB is an Lorentz invariant object, possesses observable properties of isotropy and homogeneity for all observers scattered across the Lobachevskian universe, and has a black body spectrum. The Lorentz invariance of CMB implies a mathematical equation for cosmological redshift for all z. The global picture of CMB, described solely in terms of the Lorentz group—SL(2C), is an infinite union of double sided quotient spaces (double fibration of the Lorentz group) taken over all parabolic stabilizers P&sub;SL(2C). The local picture of CMB (as seen by us from Earth) is a Grassmannian space of an infinite union all horospheres containing origin o&isin;L3, equivalent to a projective plane RP2. The space of electromagnetic wavefronts has a natural identification with the boundary at infinity (an absolute) of Lobachevskian universe. In this way, it is possible to regard the CMB as a reference at infinity (an absolute reference) and consequently to define an absolute motion and absolute rest with respect to CMB, viewed as an infinitely remote reference. 展开更多
关键词 CMB Cosmological Redshift Non-Expanding UNIVERsE Hyperbolic geometry Horospherical Electromagnetic Waves Hubble’s Error
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Quantum Dark Energy from the Hyperbolic Transfinite Cantorian Geometry of the Cosmos 被引量:1
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作者 Mohamed S. El Naschie 《Natural Science》 2016年第3期152-159,共8页
The quintessence of hyperbolic geometry is transferred to a transfinite Cantorian-fractal setting in the present work. Starting from the building block of E-infinity Cantorian spacetime theory, namely a quantum pre-pa... The quintessence of hyperbolic geometry is transferred to a transfinite Cantorian-fractal setting in the present work. Starting from the building block of E-infinity Cantorian spacetime theory, namely a quantum pre-particle zero set as a core and a quantum pre-wave empty set as cobordism or surface of the core, we connect the interaction of two such self similar units to a compact four dimensional manifold and a corresponding holographic boundary akin to the compactified Klein modular curve with SL(2,7) symmetry. Based on this model in conjunction with a 4D compact hy- perbolic manifold M(4) and the associated general theory, the so obtained ordinary and dark en- ergy density of the cosmos is found to be in complete agreement with previous analysis as well as cosmic measurements and observations such as WMAP and Type 1a supernova. 展开更多
关键词 Dark Energy Accelerated Cosmic Expansion Hyperbolic geometry Fractal geometry Transfinite set Theory ‘tHooft Dimensional Regularization Hardy’s Quantum Entanglement Davis Hyperbolic Manifold Compactified Klein Modular Curve Fractal Counting Lie symmetry Groups stein spaces
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顾及地球曲率及椭球高的GNSS-R几何计算方法
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作者 宋敏峰 何秀凤 +3 位作者 王笑蕾 肖儒雅 贾东振 李伟强 《测绘学报》 EI CSCD 北大核心 2023年第6期884-894,共11页
全球卫星导航系统反射测量(GNSS-R)技术中,观测几何计算不仅涉及GNSS反射信号的在轨实时处理,而且与观测值的地理位置计算直接相关,对其进行精确计算十分重要。当前GNSS-R技术逐步向陆地场景拓展,已有几何计算方法难以满足多场景(海洋... 全球卫星导航系统反射测量(GNSS-R)技术中,观测几何计算不仅涉及GNSS反射信号的在轨实时处理,而且与观测值的地理位置计算直接相关,对其进行精确计算十分重要。当前GNSS-R技术逐步向陆地场景拓展,已有几何计算方法难以满足多场景(海洋、陆地、冰川等)应用的需求。针对此,本文提出了一种顾及地球曲率和椭球高的几何计算方法。该方法同时也集成了一种镜面点初始估计模型,在不同轨道高度(300~900 km)和观测几何条件下,初始估计误差精度可降低至5 km以内。本文方法可基于WGS-84椭球面和顾及反射面椭球高精确计算镜面反射点,精度可控在1 mm以内,计算效率相比已有方法有显著提升,可对未来考虑地形高度的高效计算需求提供借鉴。本文方法通过变换迭代方程可进行反射信号的几何路径计算,实现从反射信号延迟观测到镜面反射点和椭球高的一体解算。与已有方法相比,本文方法考虑了地球曲率及反射点随椭球高度变化的空间偏移误差,可避免测高应用中测量值定位不准确的问题。 展开更多
关键词 GNss-R 几何计算 初始镜面反射点 地球曲率 椭球高
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The Relativistic Geometry of the Complex Matter Space
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作者 Reza Ahangar 《Journal of Applied Mathematics and Physics》 2017年第2期422-438,共17页
Duality behavior of photons in wave-particle property has posed challenges and opportunities to discover other frontiers of fundamental particles leading to the relativistic and quantum description of matter. The spee... Duality behavior of photons in wave-particle property has posed challenges and opportunities to discover other frontiers of fundamental particles leading to the relativistic and quantum description of matter. The speed of particles faster than the speed of light could not be recognized, and matter was always described as a real number. A new fundamental view on matter as a complex value has been introduced by many authors who present a paradigm that is shifted from real or pure imaginary particles to Complex Matter Space. A new assumption will be imposed that matter has two intrinsic components: i) mass, and ii) charge. The mass will be measured by real number systems and charged by an imaginary unit. The relativistic concept of Complex Matter Space on energy and momentum is investigated and we can conclude that the new Complex Matter Space (CMS) theory will help get one step closer to a better understanding toward: 1) Un-Euclidean description of Minkowski Geometry in the context of the Complex Matter Space, 2) transformation from Euclidean to Minkowski space and its relativistic interpretation. Finally, geometrical foundations are essential to have a real picture of space, matter, and the universe. 展开更多
关键词 RELATIVIsTIC geometry MAss and CHARGE Complex MATTER sPACE Un-Euclidean Minkowski’s geometry
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The Mathematics of Harmony, Hilbert’s Fourth Problem and Lobachevski’s New Geometries for Physical World
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作者 Alexey Stakhov Samuil Aranson 《Journal of Applied Mathematics and Physics》 2014年第7期457-494,共38页
We suggest an original approach to Lobachevski’s geometry and Hilbert’s Fourth Problem, based on the use of the “mathematics of harmony” and special class of hyperbolic functions, the so-called hyperbolic Fibonacc... We suggest an original approach to Lobachevski’s geometry and Hilbert’s Fourth Problem, based on the use of the “mathematics of harmony” and special class of hyperbolic functions, the so-called hyperbolic Fibonacci l-functions, which are based on the ancient “golden proportion” and its generalization, Spinadel’s “metallic proportions.” The uniqueness of these functions consists in the fact that they are inseparably connected with the Fibonacci numbers and their generalization― Fibonacci l-numbers (l > 0 is a given real number) and have recursive properties. Each of these new classes of hyperbolic functions, the number of which is theoretically infinite, generates Lobachevski’s new geometries, which are close to Lobachevski’s classical geometry and have new geometric and recursive properties. The “golden” hyperbolic geometry with the base (“Bodnar’s geometry) underlies the botanic phenomenon of phyllotaxis. The “silver” hyperbolic geometry with the base ?has the least distance to Lobachevski’s classical geometry. Lobachevski’s new geometries, which are an original solution of Hilbert’s Fourth Problem, are new hyperbolic geometries for physical world. 展开更多
关键词 Euclid’s Elements “Golden” and “Metallic” PROPORTIONs MATHEMATICs of HARMONY Hyperbolic FIBONACCI Functions Lobachevski’s geometry Hilbert’s FOURTH PROBLEM
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Geometry Sensitivity of Magnetohydrodynamic Duct Flow and Some Abnormal Phenomena
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作者 许增裕 潘传杰 +3 位作者 张秀杰 赵丽 段旭如 刘永 《Plasma Science and Technology》 SCIE EI CAS CSCD 2009年第4期499-503,共5页
Geometry sensitivity of magnetohydrodynamics (MHD) duct flow and some ab- normal phenomena deviating from the classical MHD laws were measured in an experimental investigation of the MHD effect of the flow channel i... Geometry sensitivity of magnetohydrodynamics (MHD) duct flow and some ab- normal phenomena deviating from the classical MHD laws were measured in an experimental investigation of the MHD effect of the flow channel inserter (FCI) duct flow. The results showed that the velocity distribution deviated from the M-type profile on the centre-plane of the cross section of the duct with small slots (in short "S-duct"). The electric potential difference in the duct wall was much lower than that given by the classical electromagnetic laws. The MHD pres- sure drop was much higher than that from the classical magneto-hydrodynamics theory. These results may help us find some new methods to reduce the MHD pressure drop, or explore other potential applications such as flow structure control. 展开更多
关键词 MHD effect geometry sensitivity s-duct
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Impact of coupling geometry on thermoelectric properties of oligophenyl-base transistor
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作者 S Ramezani Akbarabadi H Rahimpour Soleimani +1 位作者 M Bagheri Tagani Z Golsanamlou 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第2期420-427,共8页
Thermal and electron transport through organic molecules attached to three-dimensional gold electrodes in two different configurations, namely para and meta with thiol-terminated junctions is studied theoretically in ... Thermal and electron transport through organic molecules attached to three-dimensional gold electrodes in two different configurations, namely para and meta with thiol-terminated junctions is studied theoretically in the linear response regime using Green's function formalism. We used thiol-terminated(–SH bond) benzene units and found a positive thermopower because the highest occupied molecular orbital(HOMO) is near the Fermi energy level. We investigated the influence of molecular length and molecular junction geometry on the thermoelectric properties. Our results show that the thermoelectric properties are highly sensitive to the coupling geometry and the molecular length. In addition, we observed that the interference effects and increasing molecular length can increase the thermoelectric efficiency of device in a specific configuration. 展开更多
关键词 coupling geometry figure of merit Green's function oligophenyl thermopower
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A Procedure for the Squaring of a Circle (of Any Radius)
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作者 Lyndon O. Barton 《Advances in Pure Mathematics》 2023年第2期96-102,共7页
This paper presents a graphical procedure for the squaring of a circle of any radius. This procedure, which is based on a novel application of the involute profile, when applied to a circle of arbitrary radius (using ... This paper presents a graphical procedure for the squaring of a circle of any radius. This procedure, which is based on a novel application of the involute profile, when applied to a circle of arbitrary radius (using only an unmarked ruler and a compass), produced a square equal in area to the given circle, which is 50 cm<sup>2</sup>. This result was a clear demonstration that not only is the construction valid for the squaring of a circle of any radius, but it is also capable of achieving absolute results (independent of the number pi (π), in a finite number of steps), when carried out with precision. 展开更多
关键词 Famous Problems in Mathematics ARCHIMEDEs College Mathematics INVOLUTE Mean Proportional Principle squaring the Circle QUADRATURE Geometer’s sketch Pad College geometry
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A Key to Solving the Angle Trisection Problem
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作者 Lyndon O. Barton 《Advances in Pure Mathematics》 2023年第9期625-634,共10页
This paper describes the methodology (or approach) that was key to the solution of the angle trisection problem published earlier in article entitled, “A Procedure For Trisecting An Acute Angle.” It was an approach ... This paper describes the methodology (or approach) that was key to the solution of the angle trisection problem published earlier in article entitled, “A Procedure For Trisecting An Acute Angle.” It was an approach that required first, designing a working model of a trisector mechanism, second, studying the motion of key elements of the mechanism and third, applying the fundamental principles of kinematics to arrive at the desired results. In presenting these results, since there was no requirement to provide a detailed analysis of the final construction, this information was not included. However, now that the publication is out, it is considered appropriate as well as instructive to explain more fully the mechanism analysis of the trisector in graphical detail, as covered in Section 3 of this paper, that formed the basis of the long sought solution to the age-old Angle Trisection Problem. 展开更多
关键词 Archimedes Construction College geometry College Mathematics Angle Trisection Trisector Famous Problems in Mathematics History of Mathematics Mechanism Analysis KINEMATICs Geometer’s sketch Pad
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A Simplified Graphical Procedure for Constructing a 10˚or 20˚Angle
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作者 Lyndon O. Barton 《Advances in Pure Mathematics》 2023年第7期442-448,共7页
This paper presents a simplified graphical procedure for constructing, using an unmarked straightedge and a compass only, a 10˚ to 20˚ angle, which is in other words, trisecting a 30˚ or 60˚ angle. The procedure, when... This paper presents a simplified graphical procedure for constructing, using an unmarked straightedge and a compass only, a 10˚ to 20˚ angle, which is in other words, trisecting a 30˚ or 60˚ angle. The procedure, when applied to the 30˚ and 60˚ angles that have been “proven” to be not trisectable, produced a construction having the identical angular relationship with Archimedes’ Construction, in which the required trisection angles were found to be 10.00000˚ and 20.00000˚ respectively (i.e. exactly one-third of the given angle or ∠E’MA = 1/3∠E’CG). Based on this identical angular relationship as well as the numerical results obtained, one can only conclude that the geometric requirements for arriving at an exact trisection of the 30˚ or 60˚ angle, and therefore the construction of a 10˚ or 20˚ angle, have been met, notwithstanding the theoretical proofs of Wantzel, Dudley, and others. Thus, the solution to the age-old trisection problem, with respect to these two angles, has been accomplished. 展开更多
关键词 Archimedes Construction College geometry Angle Trisection Trisection of an Angle Famous Problems in Mathematics. Geometer’s sketch Pad Mechanisms Mechanism Analysis KINEMATICs Trisector
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Polysurfacic Tori or Kideas Inspired by the Möbius Strip Topology
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作者 Emmanuel Cadier Anaxhaoza 《Advances in Pure Mathematics》 2023年第9期543-551,共9页
Polysurfacic tori or kideas are three-dimensional objects formed by rotating a regular polygon around a central axis. These toric shapes are referred to as “polysurfacic” because their characteristics, such as the n... Polysurfacic tori or kideas are three-dimensional objects formed by rotating a regular polygon around a central axis. These toric shapes are referred to as “polysurfacic” because their characteristics, such as the number of sides or surfaces separated by edges, can vary in a non-trivial manner depending on the degree of twisting during the revolution. We use the term “Kideas” to specifically denote these polysurfacic tori, and we represent the number of sides (referred to as “facets”) of the original polygon followed by a point, while the number of facets from which the torus is twisted during its revolution is indicated. We then explore the use of concave regular polygons to generate Kideas. We finally give acceleration for the algorithm for calculating the set of prime numbers. 展开更多
关键词 Heavenly Things Topology Euclidian geometry Möbius strip Emmanuel’s Tori YiBoLong’s Tori Cadier’s Tori Möbius Tori Polysurfacic Tori Kideas The Keys KideaCross Kideastar Churros Algorithm for Calculating the set of Prime Numbers P The Last Found Element of P
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A Fractal Orifice-Throat Model for Seepage Characteristics of Multiscale Porous Media
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作者 Chunling Wang Yan Gao +1 位作者 Lida Zhang Jiaoyan Zhu 《Journal of Mechanics Engineering and Automation》 2023年第5期136-142,共7页
The seepage characteristics of multiscale porous media is of considerable significance in many scientific and engineering fields.The Darcy permeability is one of the key macroscopic physical properties to characterize... The seepage characteristics of multiscale porous media is of considerable significance in many scientific and engineering fields.The Darcy permeability is one of the key macroscopic physical properties to characterize the seepage capacity of porous media.Therefore,based on the statistically fractal scaling law of porous media,fractal geometry is applied to model the multiscale pore structures.And a two-dimensional fractal orifice-throat model with multiscale and tortuous characteristics is proposed for the seepage flow through porous media.The analytical expression for Darcy permeability of porous media is derived,which is validated by comparing with available experimental data.The results show that the Darcy permeability is significantly influenced by porosity,orifice-throat fractal dimension,minimum to maximum diameter ratio,orifice-throat ratio and tortuosity fractal dimension.The present results are helpful for understanding the seepage mechanism of multiscale porous media,and may provide theoretical basis for unconventional oil and gas exploration and development,porous phase transition energy storage composites,CO2 geological sequestration,environmental protection and nuclear waste treatment,etc. 展开更多
关键词 Multiscale porous media fractal geometry Darcy’s law PERMEABILITY orifice-throat model.
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D-S证据理论在车辆几何参数动态测量中的应用
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作者 孙红雨 向阳 郭银景 《计算机应用》 CSCD 北大核心 2009年第6期1731-1734,1737,共5页
利用多个超声波传感器组成传感器阵列对行驶车辆的几何参数进行动态扫描,采用D-S证据理论多传感器数据融合算法,对多个传感器采集的数据进行融合,将在DSP上融合的结果上传至上位机,由上位机分析行驶车辆的车长、车宽、车高、车速,为交... 利用多个超声波传感器组成传感器阵列对行驶车辆的几何参数进行动态扫描,采用D-S证据理论多传感器数据融合算法,对多个传感器采集的数据进行融合,将在DSP上融合的结果上传至上位机,由上位机分析行驶车辆的车长、车宽、车高、车速,为交通管理提供技术保障和原始数据支撑。测试结果表明,该方法可以更准确的测量车辆几何参数。 展开更多
关键词 D—s证据理论 车辆几何参数 动态测量
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平面Bonnesen等周不等式的进一步加强
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作者 吴莉 杨仕椿 《洛阳师范学院学报》 2008年第2期35-36,共2页
设欧氏平面R2中域D的面积为A,周长为L,r及R分别为D的最大内接圆半径及最小外接圆半径。利用参考文献中和分几何方法,给出了平面Bonnesen等周不等式的进一步加强,证明了L2-4πA≥π2(R-r)2(πR+πr-L)2.
关键词 Bonnesen等周不等式 积分几何方法 运动公式 Euler—Poincare示性数
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搅拌针形状对搅拌摩擦焊焊缝S曲线形成的影响 被引量:7
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作者 谢腾飞 邢丽 +2 位作者 柯黎明 栾国红 董春林 《热加工工艺》 CSCD 北大核心 2008年第7期64-66,82,共4页
采用四种不同形状搅拌针的搅拌头进行搅拌摩擦焊试验,研究了搅拌针形状对LF6铝合金搅拌摩擦焊焊缝S曲线形成的影响。结果表明:通过改变搅拌针形状可以改变焊缝塑化金属的流动行为及结合面材料的破碎程度,从而影响S曲线的形成。当焊接参... 采用四种不同形状搅拌针的搅拌头进行搅拌摩擦焊试验,研究了搅拌针形状对LF6铝合金搅拌摩擦焊焊缝S曲线形成的影响。结果表明:通过改变搅拌针形状可以改变焊缝塑化金属的流动行为及结合面材料的破碎程度,从而影响S曲线的形成。当焊接参数一定时,在光面搅拌针中,圆锥光面搅拌针较圆柱光面搅拌针更易形成S曲线;表面带螺纹搅拌针中,圆柱右旋螺纹搅拌针较圆柱左旋螺纹搅拌针更易形成S曲线。搅拌针形状不变,降低焊接速度,可以改善焊缝塑化金属流动性,使结合面材料的分布不连续,S曲线逐渐消失。 展开更多
关键词 搅拌摩擦焊 s曲线 搅拌针形状 塑性流动
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基于余震重定位和震源机制解研究青海玛多M_(S)7.4地震序列的发震构造和断裂形态 被引量:9
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作者 张建勇 王新 +1 位作者 陈凌 刘杰 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2022年第2期552-562,共11页
2021年5月22日02时04分(北京时间),青海果洛州玛多县发生M_(S)7.4地震,震后余震不断.地质调查和卫星观测对地表断裂痕迹有较好的约束.然而,对于理解区域应力场、地震的产生、传播和终止具有重要意义的地下断层几何结构的约束精度略显不... 2021年5月22日02时04分(北京时间),青海果洛州玛多县发生M_(S)7.4地震,震后余震不断.地质调查和卫星观测对地表断裂痕迹有较好的约束.然而,对于理解区域应力场、地震的产生、传播和终止具有重要意义的地下断层几何结构的约束精度略显不足.利用国家地震台网的连续波形记录,本研究首先基于双差定位法对玛多地震震后25天的余震序列进行重定位,结果显示余震序列大致沿NWW向的江错断裂呈线性分布,位于主震震中两侧,延伸总长~170 km.主震东南侧存在一余震稀疏区,在断裂带东西两端余震分布转向且出现分叉现象,反映出发震断层的复杂几何形态,这与前人研究结果基本一致.进一步采用波形反演方法和P波初动极性反演方法,获得了玛多震源区132个中小余震的震源机制解与震源矩心深度,并基于此对该主余型地震的发震构造与断裂形态进行了初步分析.震源机制解结果表明,玛多M_(S)7.4主震的发震断裂主要为左旋走滑性质,余震与主震性质整体相同,在断裂带东段存在部分逆冲型余震.震源机制解约束的区域主应力方向约N60°E,与区内整体走滑断裂作用相一致.余震震源深度略微起伏,主要集中在10~12 km,且浅部余震较少,表明浅部应力可能主要通过主震释放,余震深度分布可能限定了主震同震破裂的下边界.玛多主震破裂起始于断裂带走向和倾向发生明显变化的位置,表明断裂带的复杂几何结构可能是此次玛多M_(S)7.4地震初始破裂空间分布的决定因素.主震破裂结束的两端都有"马尾状"构造(或次级断层),表明这种分叉断层复杂的几何形态可能控制着主震破裂的最终位置. 展开更多
关键词 玛多M_(s)7.4地震 双差定位 震源机制解 发震构造 破裂形态
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