scholarly journals Algebraic determination of back-projection operators for optoacoustic tomography

2018 ◽  
Vol 9 (11) ◽  
pp. 5173 ◽  
Author(s):  
Amir Rosenthal
Keyword(s):  
Projection Operators ◽  
Back Projection ◽  
Optoacoustic Tomography

Determination of Location and Shape of Metallic Object in CT Based on Tangent Back-Projection

2013 ◽  
Vol 28 (2) ◽  
pp. 295-299
Author(s):  
李铭 LI Ming ◽  
张涛 ZHANG Tao ◽  
郑健 ZHENG Jian ◽  
杨宏成 YANG Hong-cheng ◽  
卢彦飞 LU Yan-fei
Keyword(s):  
Back Projection ◽  
Metallic Object

scholarly journals Non-invasive determination of murine placental and foetal functional parameters with multispectral optoacoustic tomography

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Kausik Basak ◽  
Xosé Luís Deán-Ben ◽  
Sven Gottschalk ◽  
Michael Reiss ◽  
Daniel Razansky
Keyword(s):  
Functional Parameters ◽  
Optoacoustic Tomography ◽  
Non Invasive

scholarly journals Quantum fluctuations of elementary excitations in discrete media

2004 ◽  
Vol 2004 (1) ◽  
pp. 169-177
Author(s):  
Hermann Haken
Keyword(s):  
Quantum Noise ◽  
General Theorem ◽  
Polymer Chains ◽  
Quantum Mechanical ◽  
Projection Operators ◽  
Noise Sources ◽  
Elementary Excitations ◽  
Heisenberg Equations ◽  
Discrete Media

Elementary excitations (electrons, holes, polaritons, excitons, plasmons, spin waves, etc.) on discrete substrates (e.g., polymer chains, surfaces, and lattices) may move coherently as quantum waves (e.g., Bloch waves), but also incoherently (“hopping”) and may lose their phases due to their interaction with their substrate, for example, lattice vibrations. In the frame of Heisenberg equations for projection operators, these latter effects are often phenomenologically taken into account, which violates quantum mechanical consistency, however. To restore it, quantum mechanical fluctuating forces (noise sources) must be introduced, whose properties can be determined by a general theorem. With increasing miniaturization, in the nanotechnology of logical devices (including quantum computers) that use interacting elementary excitations, such fluctuations become important. This requires the determination of quantum noise sources in composite quantum systems. This is the main objective of my paper, dedicated to the memory of Ilya Prigogine.

The many electron problem

1972 ◽  
Vol 72 (1) ◽  
pp. 123-134 ◽  
Author(s):  
J. A. De Wet
Keyword(s):  
Angular Momentum ◽  
Shell Structure ◽  
Dirac Particle ◽  
Irreducible Representations ◽  
Projection Operators ◽  
Atomic Shell ◽  
Atomic Shell Structure ◽  
Experimental Justification ◽  
The Many

1. Introduction. In a paper on the many nucleon problem (l), which we shall henceforth call I, the determination of the irreducible representations of the four-dimensional unitary group were found from a decomposition of its infinitesimal ring U04 The method of decomposition made use of the four primitive four-component idempotents (projection operators) of the Dirac ring each of which, as was recognized long ago by Eddington (2), can be identified with a possible charge-spin state of a Dirac particle. Some experimental justification for the representations was also provided, and it is the purpose of this paper to apply the same tools to the many electron problem. In particular, matrices will be derived for the spin multiplets of a system of r electrons, and it will be shown how the model can account for the atomic shell structure and orbital angular momentum.

Automatic Closed-Form Kinematics-Solutions for Recursive Single-Loop Chains

1992 ◽  
Author(s):  
Andrés Kecskeméthy ◽  
Manfred Hiller
Keyword(s):  
Closed Form ◽  
Isotropy Group ◽  
Projection Operators ◽  
Closure Condition ◽  
Single Loop ◽  
Closed Form Solutions ◽  
Point Line ◽  
Geometric Elements ◽  
Scalar Equations

Abstract Described in this paper is a simplified method for the automatic detection and formulation of closed-form solutions for a special class of recursively solvable single-loop mechanisms. The objective is to generate a cascade of scalar equations from the closure condition of the loop, each containing exactly one unknown more than the predecessors, and each being maximally second-order in this unknown. In the proposed method this problem is reduced to the repeated determination of two subchains which are members of the isotropy group of either of the geometric elements point, line and plane and containing as much current unknowns as possible. The scalar equations then arise from unique projection operators applied to unique equation partitionings of the closure condition. This yields a general but easy-to-implement algorithm. The concepts are illustrated with some examples processed with an implementation in Mathematica based on the geometric elements point and plane.

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