On the basis of the liquid drop model of atomic nuclei, an account is given of the mechanism of nuclear fission. In particular, conclusions are drawn regarding the variation from nucleus to nucleus of the critical energy required for fission, and regarding the dependence of fission cross section for a given nucleus on energy of the exciting agency. A detailed discussion of the observations is presented on the basis of the theoretical considerations. Theory and experiment fit together in a reasonable way to give a satisfactory picture of nuclear fission. Learn about our response to COVID , including freely available research and expanded remote access support.
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A critical review on some aspects of the theory of fission. The lecture notes display briefly some of the facets which eventually will be part of a theory for the fission process. They cover some important aspects of our present understanding in a qualitative fashion and complement the existing review articles rather than replacing them. Consistent dynamical and statistical description of fission and comparison. The research survey of consistent dynamical and statistical description of fission is briefly introduced.
The channel theory of fission with diffusive dynamics based on Bohr channel theory of fission and Fokker-Planck equation and Kramers-modified Bohr-Wheeler expression according to Strutinsky method given by P. Frobrich et al. Equilibrium fission model calculations. In order to aid in understanding the systematics of heavy ion fission and fission-like reactions in terms of the target-projectile system, bombarding energy and angular momentum, fission widths are calculated using an angular momentum dependent extension of the Bohr-Wheeler theory and particle emission widths using angular momentum coupling.
Theoretical nuclear fission: The evolution of the first fifty years. The evolution of the dynamical theory of nuclear fission is reviewed through four recognizable major phases. Its conceptual structure was from the outset shaped by the Bohr-Wheeler idea of the nucleus as a liquid drop. On the other hand, today's nuclear drop is a system which has under study repeatedly revealed remarkable and unexpected properties, especially with respect to the dependence of its energy upon its shape.
Although some of these special properties arise from quantal effects, the theory of fission is still expressed largely in terms of classical dynamics. This situation leaves open the question whether our theoretical success flows entirely from physical truth or in part from the great phenomenological flexibility of the drop model. It leads one also to wonder whether in the next phase connections with the quantal many-body dynamics might finally find a firm place in the theory , and tie its predictions quantitatively to the deeper microscopic reality.
Waltz's Theory of Theory. Followers and critics alike have treated Waltzian neorealism as if it was at bottom a formal proposition about cause-effect relations. The extreme case of Waltz being so victorious in the discipline, and yet being consistently mis-interpreted on the question of theory To help this new agenda Ring Theory. The papers in this proceedings volume are selected research papers in different areas of ring theory , including graded rings, differential operator rings, K- theory of noetherian rings, torsion theory , regular rings, cohomology of algebras, local cohomology of noncommutative rings.
The book will be important for mathematicians active in research in ring theory. Game theory. Game Theory is a collection of short interviews based on 5 questions presented to some of the most influential and prominent scholars in game theory.
We hear their views on game theory , its aim, scope, use, the future direction of game theory and how their work fits in these respects String theory.
The String theory is discussed with respect to the interaction of strings, the inclusion of both gauge theory and gravitation, inconsistencies in the theory , and the role of space-time.
The physical principles underlying string theory are also outlined. String theory or field theory? The status of string theory is reviewed, and major recent developments - especially those in going beyond perturbation theory in the string theory and quantum field theory frameworks - are analyzed. This analysis helps better understand the role and place of experimental phenomena, it is emphasized that there are some insurmountable problems inherent in it - notably the impossibility to formulate the quantum theory of gravity on its basis - which prevent it from being a fundamental physical theory of the world of microscopic distances.
It is this task, the creation of such a theory , which string theory , currently far from completion, is expected to solve. In spite of its somewhat vague current form, string theory has already led to a number of serious results and greatly contributed to progress in the understanding of quantum field theory. It is these developments, which are our concern in this review [ru. Supergravity theories.
Of all supergravity theories , the maximal, i. The harmonic superspace was recently proposed which may be useful to investigate the quantum effects of extended supersymmetry and supergravity theories.
As to the so-called Kaluza-Klein supergravity, there is another possibility. Mori, K. Topos theory. Focusing on topos theory 's integration of geometric and logical ideas into the foundations of mathematics and theoretical computer science, this volume explores internal category theory , topologies and sheaves, geometric morphisms, other subjects. Probability theory. This book of problems is intended for students in pure and applied mathematics.
There are problems in traditional areas of probability theory and problems in the theory of stochastic processes, which has wide applications in the theory of automatic control, queuing and reliability theories , and in many other modern science and engineering fields. Answers to most of the problems are given, and the book provides hints and solutions for more complicated problems.
Gauge theories. Some introductory remarks to Yang-Mills fields are given and the problem of the Coulomb gauge is considered. The perturbation expansion for quantized gauge theories is discussed and a survey of renormalization schemes is made.
The role of Ward-Takahashi identities in gauge theories is discussed. The author then discusses the renormalization of pure gauge theories and theories with spontaneously broken symmetry. Atomic theories. Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory , the Bohr Theory , the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena.
Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec. Grounded theory. Grounded theory is a popular research approach in health care and the social sciences. This article provides a description of grounded theory methodology and its key components, using examples from published studies to demonstrate practical application. It aims to demystify grounded theory for novice nurse researchers, by explaining what it is, when to use it, why they would want to use it and how to use it.
It should enable nurse researchers to decide if grounded theory is an appropriate approach for their research, and to determine the quality of any grounded theory research they read. Number theory via Representation theory. Eknath Ghate. November 9, Eightieth Annual Meeting, Chennai. Indian Academy of Sciences1. This is a non-technical 20 minute talk intended for a general Academy audience. Superstring theory. Dual string theories , initially developed as phenomenological models of hadrons, now appear more promising as candidates for a unified theory of fundamental interactions.
Type I superstring theory SST I , is a ten-dimensional theory of interacting open and closed strings, with one supersymmetry, that is free from ghosts and tachyons. It requires that an SO eta or Sp 2eta gauge group be used. A light-cone-gauge string action with space-time supersymmetry automatically incorporates the superstring restrictions and leads to the discovery of type II superstring theory SST II.
The superstring theories can be described by a light-cone-gauge action principle based on fields that are functionals of string coordinates. With this formalism any physical quantity should be calculable. There is some evidence that, unlike any conventional field theory , the superstring theories provide perturbatively renormalizable SST I or finite SST II unifications of gravity with other interactions.
This analysis helps better understand the role and place of string theory in the modern picture of the physical world. Even though quantum field theory describes a wide range of experimental phenomena, it is emphasized that there are some insurmountable problems inherent in it - notably the impossibility to formulate the quantum theory of gravity on its basis - which prevent it from being a fundamental physical theory of the world of microscopic distances.
It is these developments which are our concern in this review. Dependence theory via game theory. In the multi-agent systems community, dependence theory and game theory are often presented as two alternative perspectives on the analysis of social interaction. Up till now no research has been done relating these two approaches.
The unification presented provides dependence theory with the sort. Model theory. Model theory deals with a branch of mathematical logic showing connections between a formal language and its interpretations or models. This is the first and most successful textbook in logical model theory.
Extensively updated and corrected in to accommodate developments in model theoretic methods - including classification theory and nonstandard analysis - the third edition added entirely new sections, exercises, and references. Each chapter introduces an individual method and discusses specific applications. Basic methods of constructing models include constants, elementary chains, Sko. Viability Theory. Viability theory designs and develops mathematical and algorithmic methods for investigating the adaptation to viability constraints of evolutions governed by complex systems under uncertainty that are found in many domains involving living beings, from biological evolution to economics, from environmental sciences to financial markets, from control theory and robotics to cognitive sciences.
It involves interdisciplinary investigations spanning fields that have traditionally developed in isolation. The purpose of this book is to present an initiation to applications of viability theory , explai. Galois Theory. Praise for the First Edition ".
Game theory is a toolkit for examining situations where decision makers influence each other. I discuss the nature of game-theoretic analysis, the history of game theory , why game theory is useful for understanding human psychology, and why game theory has played a key role in the recent explosion of interest in the field of behavioral economics.
Elastoplasticity theory. This book details the mathematics and continuum mechanics necessary as a foundation of elastoplasticity theory. It explains physical backgrounds with illustrations and provides descriptions of detailed derivation processes.. Perturbation theory.
N6. Bohr-Wheeler Theory Of Fission
A critical review on some aspects of the theory of fission. The lecture notes display briefly some of the facets which eventually will be part of a theory for the fission process. They cover some important aspects of our present understanding in a qualitative fashion and complement the existing review articles rather than replacing them. Consistent dynamical and statistical description of fission and comparison. The research survey of consistent dynamical and statistical description of fission is briefly introduced. The channel theory of fission with diffusive dynamics based on Bohr channel theory of fission and Fokker-Planck equation and Kramers-modified Bohr-Wheeler expression according to Strutinsky method given by P. Frobrich et al.