A NEW METHOD FOR CALCULATING CLASSICAL PERIODIC TRAJECTORIES IN TWO DIMENSIONS

1994 ◽  
Vol 04 (02) ◽  
pp. 251-264 ◽  
Author(s):  
K.T.R. DAVIES
Keyword(s):  
Periodic Orbits ◽  
Gaussian Elimination ◽  
Two Dimensions ◽  
Point Of View ◽  
The Other ◽  
New Method ◽  
Two Dimensional ◽  
Many Body ◽  
Periodic Trajectories ◽  
Dimensional Phase Space

Previously, the monodromy method has been widely used for calculating classical periodic trajectories for a two-dimensional Hamiltonian system, or a four-dimensional phase space. In this paper, the problem is formulated from a different point of view, involving Gaussian-elimination algorithms. Thus, we present a new method for calculating classical periodic orbits, in which each of the basic matrices is of dimension two. Two variants are obtained, one assuming that the period of the motion is fixed and the other assuming that the total energy is fixed. We emphasize the importance of calculating the periodic orbits in as small a dimensionality as possible, an advantage which has implications for generalizations of the theory and methods to outstanding many-body problems in nuclear and atomic physics. Comparisons are made between various approaches.

scholarly journals CO and OH in the Galactic Center Region

1980 ◽  
Vol 87 ◽  
pp. 111-112
Author(s):  
Junji Inatani ◽  
Nobuharu Ukita
Keyword(s):  
Emission Line ◽  
Intensity Ratio ◽  
Molecular Clouds ◽  
Galactic Center ◽  
Point Of View ◽  
The Other ◽  
Kinetic Temperature ◽  
Two Dimensional ◽  
Center Region ◽  
Dimensional Distribution

The two-dimensional distribution of molecular clouds in the galactic center region has been investigated in the CO 115 GHz line and in the OH 1665 and 1667 MHz lines. As the former is an emission line, we can find molecular clouds without the unavoidable bias to continuum sources which is inherent in a survey of OH absorption lines. Because the CO line is usually optically thick, the brightness temperature of the line is directly related to the kinetic temperature of the cloud. On the other hand, the real optical depth of the OH line can be obtained from the intensity ratio between 1665 and 1667 MHz lines (assuming LTE). From this point of view we have compared the CO and OH observational results.

LUTTINGER-LIQUID BEHAVIOUR IN 2D: THE VARIATIONAL APPROACH

1993 ◽  
Vol 07 (03) ◽  
pp. 119-141 ◽  
Author(s):  
CLAUDIUS GROS ◽  
ROSER VALENTÍ
Keyword(s):  
Monte Carlo ◽  
Variational Formulation ◽  
Variational Approach ◽  
Order Parameter ◽  
Luttinger Liquid ◽  
Two Dimensions ◽  
Point Of View ◽  
Two Dimensional ◽  
Liquid Type ◽  
D Wave

We study a variational formulation of the Luttinger-liquid concept in two dimensions. We show that a Luttinger-liquid wavefunction with an algebraic singularity at the Fermiedge is given by a Jastrow-Gutzwiller type wavefunction, which we evaluate by variational Monte Carlo for lattices with up to 38 × 38 = 1444 sites. We therefore find that, from a variational point of view, the concept of a Luttinger liquid is well defined even in 2D. We also find that the Luttinger liquid state is energetically favoured by the projected kinetic energy in the context of the 2D t-J model. We study and find coexistence of d-wave superconductivity and Luttinger-liquid behaviour in two-dimensional projected wavefunctions. We then argue that generally, any two-dimensional d-wave superconductor should be unstable against Luttinger-liquid type correlations along the (quasi-1D) nodes of the d-wave order parameter, at temperatures small compared to the gap.

Two-dimensional analysis of spatial pattern in vegetation for site comparison

1990 ◽  
Vol 68 (1) ◽  
pp. 149-158 ◽  
Author(s):  
M. R. T. Dale
Keyword(s):  
Spatial Pattern ◽  
Dimensional Analysis ◽  
Satellite Imagery ◽  
Two Dimensions ◽  
Vegetation Classification ◽  
New Method ◽  
Two Dimensional ◽  
Vegetation Composition ◽  
Artificial Data ◽  
Rectangular Grids

A new method for the analysis of spatial pattern in two dimensions is described. The technique uses data collected in square or rectangular grids of quadrats to examine the scale of pattern in vegetation, no matter how the grids are oriented with respect to the pattern. Its usefulness is demonstrated by application to artificial data. The method is also applied to vegetation classification data derived from LANDSAT TM satellite imagery of a valley in the Yukon, Canada, in which the effects of experimental manipulations on boreal communities are being studied. A set of 2 × 2 km squares of the valley were selected for analysis in which the vegetation composition squares varies considerably. The analysis shows that most of the squares had one and only one scale of two dimensional pattern, consistently in the range of 360–780 m.

A Multiparticle Lattice-Gas Model for Hydrodynamics

1998 ◽  
Vol 09 (08) ◽  
pp. 1221-1230 ◽  
Author(s):  
A. Masselot ◽  
B. Chopard
Keyword(s):  
Cellular Automata ◽  
Lattice Model ◽  
Lattice Boltzmann ◽  
Lattice Gas ◽  
Two Dimensions ◽  
The Other ◽  
Many Body ◽  
The Many ◽  
Ballistic Annihilation ◽  
Fluid Parameters

Cellular automata (CA) and lattice-Boltzmann (LB) models are two possible approaches to simulate fluid-like systems. CA models keep track of the many-body correlations and provide a description of the fluctuations. However, they lead to a noisy dynamics and impose strong restrictions on the possible viscosity values. On the other hand, LB models are numerically more efficient and offer much more flexibility to adjust the fluid parameters, but they neglect fluctuations. Here we discuss a multiparticle lattice model which reconciles both approaches. Our method is tested on Poiseuille flows and on the problem of ballistic annihilation in two dimensions for which the fluctuations are known to play an important role.

Success, Failure, and Personality

1963 ◽  
Vol 13 (2) ◽  
pp. 567-574 ◽  
Author(s):  
Harold H. Kassarjian
Keyword(s):  
Mental Illness ◽  
Personality Traits ◽  
Two Dimensions ◽  
The Other ◽  
Self Concept ◽  
Objective Measures ◽  
Two Dimensional ◽  
Moderate Correlation ◽  
Cultural Patterns ◽  
The Individual

The cultural patterns of success and failure were defined as a two-dimensional process. The first is indicated by objective measures of achievement, the “societal” success-failure continuum; the other by the aspirations of the individual and his self perception of success or failure. Results indicate a moderate correlation (.51) between the two dimensions. Failure on both dimensions was found to be related to a poorer self concept, fewer adjustive attitudes, greater complaints of physical and mental illness symptoms and less socially desirable personality traits than found in individuals who score as successful on both criteria. Some variables were found to be primarily related to the psychological failure dimension and others primarily related to societal failure.

scholarly journals Nanometric SiC influence on tribological properties of phenolic composite materials

2021 ◽  
Vol 13 (1) ◽  
pp. 131-140
Author(s):  
George PELIN
Keyword(s):  
Composite Materials ◽  
Phenolic Resin ◽  
Point Of View ◽  
The Other ◽  
Two Dimensional ◽  
Carbon Felt ◽  
Different Types ◽  
The Coefficient Of Friction ◽  
Laminated Materials ◽  
Phenolic Composite

This paper presents an experimental study of the influence of nano metric silicon carbide in the composition of phenolic composites on the coefficient of friction. The paper is divided into three distinct parts investigating from a tribological point of view three different types of composite materials based on phenolic resin with three concentrations of nSiC (0.5; 1 and 2% by mass). In the first part, a comparative study of the behavior of phenolic resin was performed, representing the basis for the development of composite materials. In the second part, a study was performed on laminated materials reinforced with two-dimensional fabrics (glass fiber and carbon fiber, respectively). The last part studied two types of ablative phenolic materials based on micronic cork, on one hand, and on carbon felt on the other hand.

scholarly journals Electron-phonon decoupling in two dimensions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
George McArdle ◽  
Igor V. Lerner
Keyword(s):  
Electron Temperature ◽  
Cooling Rate ◽  
Two Dimensions ◽  
Electronic Systems ◽  
Two Dimensional ◽  
Many Body ◽  
Current Voltage ◽  
Current Voltage Characteristics

AbstractIn order to observe many-body localisation in electronic systems, decoupling from the lattice phonons is required, which is possible only in out-of-equilibrium systems. We show that such an electron-phonon decoupling may happen in suspended films and it manifests itself via a bistability in the electron temperature. By studying the electron-phonon cooling rate in disordered, suspended films with two-dimensional phonons, we derive the conditions needed for such a bistability, which can be observed experimentally through hysteretic jumps of several orders of magnitude in the nonlinear current-voltage characteristics. We demonstrate that such a regime is achievable in systems with an Arrhenius form of the equilibrium conductivity, while practically unreachable in materials with Mott or Efros–Shklovskii hopping.

Stereotyping Older Workers and Retirement: The Managers' Point of View

2005 ◽  
Vol 24 (4) ◽  
pp. 353-366 ◽  
Author(s):  
Kène Henkens
Keyword(s):  
Older Workers ◽  
Organizational Factors ◽  
Two Dimensions ◽  
Point Of View ◽  
The Other ◽  
Three Dimensions ◽  
Older Employees ◽  
Psychological Mechanisms ◽  
Frequent Contact ◽  
Components Analysis

ABSTRACTThis article presents the results of a study into stereotyping by managers of their older workers and the influence of these stereotypes on the inclination of managers to keep their older workers in employment. The data for the study were gathered among 796 managers. Through principal components analysis, 15 opinions about older workers were reduced to three dimensions of stereotypes. The first dimension deals with the productivity of older staff; the other two dimensions have to do with their reliability and their adaptability. These stereotypical ideas about older workers influence managers' attitudes toward the retirement of their employees. The analyses show that, besides organizational factors, psychological mechanisms also explain why people view older workers through stereotypes. Managers who are older and in more frequent contact with older employees tend to hold more positive views.

Source and Sink Method of Solution of Two-Dimensional Phase Change for Energy Storage

1994 ◽  
Vol 116 (2) ◽  
pp. 100-106 ◽  
Author(s):  
Hongjun Li ◽  
C. K. Hsieh ◽  
D. Y. Goswami
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Two Dimensions ◽  
The Other ◽  
Two Dimensional ◽  
Melting Front ◽  
Method Of Solution ◽  
Difference Form ◽  
Change Problem ◽  
Source And Sink

A source and sink method has been developed for the solution of heat transfer with phase change in two dimensions. In this method, the heat transfer in one direction is decoupled from that in the other direction by changing the second partial differential in the direction where the phase change is less dominant to a finite difference form and solving the problem in the other direction with an analytical solution that accounts for the motion of the interface in a phase-change problem. The solution developed in this paper is thus independent of the equations used to represent the interface as well as the conditions imposed on the boundaries. In the present paper, the method has been applied to the tracking of a single melting front formed by different phases assuming equal properties. The method has been demonstrated to be accurate, convergent, and stable by numerical computations as well as experimental measurements. Extension of the method to more general problems has also been discussed.

scholarly journals A REJECTION MECHANISM IN 2D BOUNDED CONFIDENCE PROVIDES MORE CONFORMITY

2008 ◽  
Vol 11 (04) ◽  
pp. 529-549 ◽  
Author(s):  
S. HUET ◽  
G. DEFFUANT ◽  
W. JAGER
Keyword(s):  
Attitude Change ◽  
Large Range ◽  
Two Dimensions ◽  
The Other ◽  
One Dimension ◽  
Two Dimensional ◽  
Number Of Clusters ◽  
Bounded Confidence ◽  
Rejection Mechanism ◽  
Model Apply

This paper explores the dynamics of attitude change in two dimensions resulting from social interaction. We add a rejection mechanism into the 2D bounded confidence (BC) model proposed by Deffuant et al. (2001). Individuals are characterized by two-dimensional continuous attitudes, each associated with an uncertainty u, supposed constant in this first study. Individuals interact through random pairs. If their attitudes are closer than u on both dimensions, or further than u on both dimensions, or closer than u on one dimension and not further than u + δ u on the other dimension, then the rules of the BC model apply. But if their attitudes are closer than u on one dimension and further than u + δ u on the other dimension, then the individuals are in a dissonant state. They tend to solve this problem by shifting away their close attitudes. The model shows metastable clusters, which maintain themselves through opposite influences of competitor clusters. Our analysis and first experiments support the hypothesis that, for a large range of uncertainty values, the number of clusters grows linearly with the inverse of the uncertainty, whereas this growth is quadratic in the BC model.

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