scholarly journals Electromagnetic Hanbury Brown and Twiss Effect in Atmospheric Turbulence

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 186
Author(s):  
Olga Korotkova ◽  
Yalçın Ata
Keyword(s):  
Atmospheric Turbulence ◽  
Single Point ◽  
Source Parameters ◽  
Stokes Parameters ◽  
Integral Approach ◽  
Unified Theory ◽  
Sensing Systems ◽  
The Matrix ◽  
Induced Changes ◽  
Scintillation Indices

The evolution of the 4 × 4 matrix with elements being the scintillation indices of the single-point Stokes parameters of a stationary electromagnetic beam-like optical field in classic, weak atmospheric turbulence is revealed. It is shown that depending on the choice of the source parameters, the source-induced changes in the matrix elements of the propagating beam and those produced by turbulence can be either range-separated or conjoined. For theoretical analysis, the unified theory of coherence and polarization is used together with the extended Huygens-Fresnel integral approach. The results can be of interest for building robust communication and sensing systems operating in the presence of atmospheric fluctuations.

The RCRRC Five-Link Space Mechanism—Displacement Analysis, Force and Torque Analysis and Its Transmission Criteria

1975 ◽  
Vol 97 (2) ◽  
pp. 581-594 ◽  
Author(s):  
Ing-Ping Jack Lee ◽  
Cemil Bagci
Keyword(s):  
Angular Displacement ◽  
Unified Theory ◽  
Eighth Order ◽  
Joint Force ◽  
Output Displacement ◽  
Displacement Equation ◽  
The Matrix ◽  
Torque Analysis ◽  
Force Components ◽  
Inertia Forces

Displacement, and force and torque analyses of the RCRRC five-link space mechanism are performed using 3 × 3 screw matrix and dual vectors. Expressions for all the displacements in the mechanism are given. Input-output displacement equation is obtained in both eighth order and 16th order polynomials in half-tangents of the angular displacement. The solution of the 16th order displacement equation shows that the RCRRC mechanism may have 16 geometric inversions for a set of dimensions. The eighth order displacement equation, which conforms with that obtained by the Unified Theory which uses dual spherical trigonometry, is an incomplete relationship and it only gives the displacements of half of the existing geometric inversions. Numerical examples and photographs of the geometric inversions are given. The force and torque analysis of the RCRRC five-link space mechanism is performed by joint force analysis. Dual inertia forces are neglected, and the motion of the mechanism is known. Explicit expressions for the dual force components at the pair locations are given, as well as the matrix solution. Transmissivities of the mechanism are defined. Force and torque analysis of one of the geometric inversions is performed in a numerical example.

Multiparameter Sturm theory

1984 ◽  
Vol 99 (1-2) ◽  
pp. 173-184 ◽  
Author(s):  
Paul Binding ◽  
Patrick J. Browne
Keyword(s):  
Elliptic Partial Differential Equation ◽  
Comparison Theorems ◽  
Unified Theory ◽  
Focal Points ◽  
The Matrix ◽  
Sturm Liouville ◽  
Left And Right ◽  
Image Position ◽  
Completeness Of Eigenfunctions ◽  
Sturm Theory

SynopsisLet Sturm–Liouville problemswith continuous coefficients and appropriate boundary conditions, be coupled by the eigenvalue λ = (λ1, … λk). When k = 1, there are various oscillation, perturbation and comparison theorems concerning existence and continuous or monotonic dependence of eigenvalues, eigenfunctions and their zeros (i.e. focal points).We attempt a unified theory for such results, valid for general fc, under conditions known as "left" and “right” definiteness. A representative result may be stated loosely as follows: if LD holds then (elementwise) monotonic dependence of p, q and the matrix [ars] forces monotonic dependence of λ. LD is a generalisation of the “polar” case for k = 1, and was originally conceived for a quite different purpose, viz. completeness of eigenfunctions via elliptic partial differential equation theory.

Towards a Multi-Decadal Dataset of Auroral Kilometric Radiation (AKR) Source Parameters with Wind/WAVES

2020 ◽  
Author(s):  
James Waters ◽  
Caitriona Jackman ◽  
Daniel Whiter ◽  
Laurent Lamy ◽  
Xavier Bonnin ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Wind Waves ◽  
Source Parameters ◽  
Source Region ◽  
Stokes Parameters ◽  
Auroral Kilometric Radiation ◽  
Wind Spacecraft ◽  
Field Lines ◽  
Auroral Arcs ◽  
The Waves

<p>Auroral Kilometric Radiation (AKR) is radio emission that originates in particle acceleration regions along magnetic field lines that coincide with discrete auroral arcs. Radio astronomy instruments aboard various spacecraft have been used to derive the flux density, source direction and other parameters of emissions of various origin. The Wind spacecraft has been in operation for 25 years and the WAVES radio instrument has previously been considered for a technique to also derive the Stokes parameters of a partially polarised radio source. While previous applications of the technique have seen it modified to study solar radio emissions, further examination is needed for its application to AKR. After correcting appropriately for the characteristics of the AKR emissions, this technique can be used to produce a utile dataset of AKR observations. Statistical properties of AKR can be examined, with the extent of local time sampling of Wind bolstering previous studies. The previously observed correlation between morphological changes in the source region and magnetospheric substorm onset can be studied further, and lists of substorm phase timings can be used to examine the general variability during these events.</p>

scholarly journals Deafferentation-Induced Redistribution of MMP-2, but Not of MMP-9, Depends on the Emergence of GAP-43 Positive Axons in the Adult Rat Cochlear Nucleus

2011 ◽  
Vol 2011 ◽  
pp. 1-17 ◽  
Author(s):  
Michaela Fredrich ◽  
Robert-Benjamin Illing
Keyword(s):  
Extracellular Matrix ◽  
Matrix Metalloproteinases ◽  
Cochlear Nucleus ◽  
Ecm Remodeling ◽  
Adult Rat ◽  
Anteroventral Cochlear Nucleus ◽  
The Matrix ◽  
Ventral Nucleus ◽  
Induced Changes ◽  
Trapezoid Body

The matrix metalloproteinases MMP-9 and MMP-2, major modulators of the extracellular matrix (ECM), were changed in amount and distribution in the rat anteroventral cochlear nucleus (AVCN) following its sensory deafferentation by cochlear ablation. To determine what causal relationships exist between the redistribution of MMP-9 and MMP-2 and deafferentation-induced reinnervation, kainic acid was stereotaxically injected into the ventral nucleus of the trapezoid body (VNTB) prior to cochlear ablation, killing cells that deliver the growth associated protein 43 (GAP-43) into AVCN. Deafferentation-induced changes in the pattern of MMP-9 staining remained unaffected by VNTB lesions. By contrast, changes in the distribution of MMP-2 normally evoked by sensory deafferentation were reversed if GAP-43 positive axons were prevented to grow in AVCN. In conclusion, GAP-43-containing axons emerging in AVCN after cochlear ablation seem to be causal for the maintenance of MMP-2-mediated ECM remodeling.

scholarly journals Methodological and applied aspects of classification and typology of international geopolitical conflicts

2020 ◽  
pp. 38-53
Author(s):  
Aleksandr Aleksandrovich Tikhov
Keyword(s):  
Integral Approach ◽  
Modern World ◽  
Key Factors ◽  
Diagnostic Features ◽  
Geographical Environment ◽  
The Matrix ◽  
Conflict Interaction ◽  
Qualitative Changes

This article is dedicated to the development of methods and applied aspects of the typology of international geopolitical conflicts in modern world. Relevance of this topic is substantiated by intensification of intergovernmental conflicts on the regional and transregional levels, as well as escalation of sociopolitical tension. The author offers a method of classification of geopolitical conflicts that considers spatial and time specificity of such forms of cooperation and is based on the comprehensive analysis of all components of the process. As one of the key factors, the author highlights the causes and prerequisites for formation of a conflict. An integral approach towards typology of the forms of conflict interaction between the countries is being developed on the basis of three-way classification matrix. The matrix is based on the three diagnostic features that characterize the key factors of formation and development of a conflict, and substantiate a subsequent model of intensification of a conflict. This allows achieving the necessary level of objectivity for conducting further complex diagnostics of geopolitical conflict and precision of the result of typology using the instruments and methodology of different scientific approaches towards studying such type of processes. The proposed method may be used in studying certain types of geopolitical conflicts of the past and present, forecasting the development and qualitative changes of a certain conflict in future, as well as comprehensive assessment of conflict potential of a particular territory of region as a whole. In the course of this work, the author established and confirmed interpretation and interdependence between the political decisions of one or another country and the corresponding geographical environment. Determination of causal lings allow viewing the method as a foundation for future examination of conflicts and forecast their development.

scholarly journals Computer Simulation of the Direct Pressing Process Through Various Matrix Funnel Profiles

2020 ◽  
pp. 3-11
Author(s):  
Sviatskyi Volodymyr ◽  
◽  
Oleksandr Skrypnyk ◽  
Serhii Kononchuk ◽  
◽  
...  
Keyword(s):  
Computer Simulation ◽  
Slip Line ◽  
Single Point ◽  
Metal Flow ◽  
Point Of View ◽  
Pressing Process ◽  
The Matrix ◽  
Deformed State ◽  
Direct Pressing ◽  
Deform 2D

The stressed and deformed state of the metal and the dimensions of the center of deformation during pressing depend significantly on the design of the tool and, in particular, on the shape of the matrix funnel. However, there is still no single point of view on the influence of the geometry of the deformation center on the energy forces of the metal pressing process. Based on the analysis of the field of slip lines of the steady-state stage of pressing through a symmetric single-point matrix, it is proposed to use the profile of the matrix funnel made along the slip line separating the elastic and plastic zones. The following types of matrix funnel profiles were investigated using computer simulation of direct extrusion of lead samples with a drawing value 81 at a speed of 1 mm/s: cycloid concave; convex; the second convex, which is built on the logarithmic dependence; conical and concave, which is built along a sliding line that separates the elastic zones from the plastic in the pressing process. The results of theoretical studies, computer simulations of the direct pressing process using the Deform 2D/3D software package, and experimental experiments have shown that optimal energy-power conditions are achieved by pressing through a matrix that has a profile made along the slip line. The results of the experimental study of the kinetics of the flow of the discrete medium showed that the shape of the matrix funnel influences the size of the deformation center and the distribution of the resulting deformation in the molding. From the analysis of deformation of the granules, it is determined that the concave funnel, built along the slip line, is characterized by a curvature of the axisymmetric particles in the direction of deformation. These curvatures decrease as the granules move to the axis of symmetry of the matrix. It is noted that for a convex funnel, the length of the deformation center is greatest; for a conical metal flow is close to the radial in the direction of the truncated cones.

scholarly journals Effect of source parameters on polarization characteristics of electromagnetic beam propagating in atmospheric turbulence

2014 ◽  
Vol 63 (10) ◽  
pp. 104201
Author(s):  
Li Cheng-Qiang ◽  
Wang Ting-Feng ◽  
Zhang He-Yong ◽  
Xie Jing-Jiang ◽  
Liu Li-Sheng ◽  
...  
Keyword(s):  
Atmospheric Turbulence ◽  
Source Parameters ◽  
Electromagnetic Beam ◽  
Polarization Characteristics

Analysis of the matrix induced changes in the optical spectra of matrix isolated noble metal atoms

1977 ◽  
Vol 66 (7) ◽  
pp. 2806-2813 ◽  
Author(s):  
F. Forstmann ◽  
D. M. Kolb ◽  
D. Leutloff ◽  
W. Schulze
Keyword(s):  
Noble Metal ◽  
Optical Spectra ◽  
Metal Atoms ◽  
The Matrix ◽  
Induced Changes
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