The Method of the Generalised Eikonal


Book Description

Diffraction theory describes scattering mechanisms for waves of various physical nature, scattered by objects of different shapes and materials. This book proposes new methods to account for the contour shape, edge profile and boundary conditions of three-dimensional scatterers (in particularly, flat polygons and polyhedrals). A standard method to refine the physical optics approximation (PO) is the heuristic method of edge waves (MEW). In comparison with MEW, the presented approaches simplify the solving and refining the PO approximation without solving a corresponding two-dimensional problem. Furthermore these methods allow to take into account the field perturbation in the vicinity of vertices. While the analytical formulas obtained by using these new approaches are as simple as in the PO case, the accuracy can be even higher than for MEW. On the basis of the developed methods construction of solutions for wave propagation in urban area and elastic wave diffraction (including seismic waves) are proposed. The book is useful for specialists who solve scientific and engineering problems in wave propagation and for students and postgraduate students.




Wavelet Analysis on the Sphere


Book Description

The goal of this monograph is to develop the theory of wavelet harmonic analysis on the sphere. By starting with orthogonal polynomials and functional Hilbert spaces on the sphere, the foundations are laid for the study of spherical harmonics such as zonal functions. The book also discusses the construction of wavelet bases using special functions, especially Bessel, Hermite, Tchebychev, and Gegenbauer polynomials.




Inside Finite Elements


Book Description

All relevant implementation aspects of finite element methods are discussed in this book. The focus is on algorithms and data structures as well as on their concrete implementation. Theory is covered only as far as it gives insight into the construction of algorithms. In the exercises, a complete FE-solver for stationary 2D problems is implemented in Matlab/Octave. Contents: Finite Element Fundamentals Grids and Finite Elements Assembly Solvers Error Estimation Mesh Refinement Multigrid Elastomechanics Fluid Mechanics Grid Data Structure Function Reference




Frontiers Of Physics 1998, Proceedings Of The Intl Mtg


Book Description

Contents:Progress of RFQ and Superconducting Accelerators in China (C E Chen et al.)QCD Phase Transition in the Laboratory and in the Early Universe (B Sinha)Frontiers in Ultrafast Laser Science (W Sibbett)Asymmetries of Sea Quark Distributions in Baryons (M Alberg et al.)A Variational Approach to Many-Particle Systems (C K Kim et al.)Synchrotron Radiation Activities at KEK (M Kihara)Results of the UNU/ICTP PFF Network (S Lee)New Generation Positron-Atom Scattering Theories (K Ratnavelu)Superconducting Pairing of Quarks in QCD (N V Hieu & L T Tuong)Photon-Gated Persistent Spectral Hole Burning (Y X Nie & L Z Zhao)Wind Driven Circulation of the South China Sea (A Camerlengo)Effect of Soil Type on Environmental Terrestrial Gamma Radiation Dose in Johor State, Malaysia (A T Ramli et al.)Research in Optical Fibres Devices at Telekom Malaysia Photonics Laboratory (H B Ahmad et al.)Simplifying Complexity (W A T Wan Abdullah)Gravitational Wave Detection in the Laboratory (Y T Chen et al.)and other papers Readership: Theoretical physicists.




Stabilisation and Motion Control of Unstable Objects


Book Description

Systems with mechanical degrees of freedom containing unstable objects are analysed in this monograph and algorithms for their control are developed, discussed, and numerically tested. This is achieved by identifying unstable modes of motion and using all available resources to suppress them. By using this approach the region of states from which a stable regime can be reached is maximised. The systems discussed in this book are models for pendula and vehicles and find applications in mechatronics, robotics as well as in mechanical and automotive engineering.




Group Theory of Chemical Elements


Book Description

In this monograph, group-theoretical approaches are used to build a system of hadrons and qualitatively describe the properties of chemical compounds. This serves as a complement to numerically and approximately solve the many-electron Schrödinger equation, in order to understand the behavior of chemical elements. Besides general theory, specific results are compared with experimentally measured chemical properties.




Noncompact Semisimple Lie Algebras and Groups


Book Description

With applications in quantum field theory, elementary particle physics and general relativity, this two-volume work studies invariance of differential operators under Lie algebras, quantum groups, superalgebras including infinite-dimensional cases, Schrödinger algebras, applications to holography. This first volume covers the general aspects of Lie algebras and group theory supplemented by many concrete examples for a great variety of noncompact semisimple Lie algebras and groups. Contents: Introduction Lie Algebras and Groups Real Semisimple Lie Algebras Invariant Differential Operators Case of the Anti-de Sitter Group Conformal Case in 4D Kazhdan–Lusztig Polynomials, Subsingular Vectors, and Conditionally Invariant Equations Invariant Differential Operators for Noncompact Lie Algebras Parabolically Related to Conformal Lie Algebras Multilinear Invariant Differential Operators from New Generalized Verma Modules Bibliography Author Index Subject Index




Springer Series in Light Scattering


Book Description

This book presents a survey of modern theoretical and experimental techniques in studies of light scattering phenomena and radiative transfer processes in random media. It presents reviews on light scattering by sea water and bubbles, and includes a separate chapter addressing studies of the remote sensing of crystalline clouds with a focus on the shape of particles—a parameter rarely studied by passive remote sensing techniques. In particular, it offers a comprehensive analysis of polarized radiative transfer in optically active (e.g., chiral) light scattering media and explores advances in spectro-polarimetry of particulate media. Lastly it discusses new developments in light scattering for combustion monitoring.




Interaction of Gases with Surfaces


Book Description

Interface phenomena are most fascinating because of the mixing of different scales and the interference of diverse physical processes. This makes it necessary to use different levels of description: microscopic, kinetic, and gas-dynamical. A unified quasiclassical approach is used to answer practical questions dealing with inelastic gas-surface scattering, the kinetics of adsorption layers, the evolution of inhomogeneities and defects at the surface, the Knudsen layer, the development of boundary conditions on the kinetic and gas-dynamical levels, the determination of exchange and slip coefficients, and so on.