scholarly journals A mobile charge densities in harmonic oscillators (MCDHO) molecular model for numerical simulations: The water–water interaction

2000 ◽  
Vol 113 (24) ◽  
pp. 10899-10912 ◽  
Author(s):  
Humberto Saint-Martin ◽  
Jorge Hernández-Cobos ◽  
Margarita I. Bernal-Uruchurtu ◽  
Iván Ortega-Blake ◽  
Herman J. C. Berendsen
Keyword(s):  
Numerical Simulations ◽  
Molecular Model ◽  
Harmonic Oscillators ◽  
Mobile Charge ◽  
Charge Densities ◽  
Water Interaction

INVARIANT EIGEN-OPERATOR METHOD FOR SOLVING ENERGY GAP FOR SOME HAMILTONIANS IN MOLECULAR PHYSICS

2007 ◽  
Vol 21 (12) ◽  
pp. 1961-1969 ◽  
Author(s):  
HONG-YI FAN ◽  
TONG-TONG WANG
Keyword(s):  
Energy Gap ◽  
Molecular Model ◽  
Energy Levels ◽  
Linear Chain ◽  
Operator Method ◽  
Harmonic Oscillators ◽  
Molecular Physics ◽  
Coupled Harmonic Oscillators ◽  
Diagonalization Method

We show that the recently proposed invariant eigen-operator method is particularly applicable to solving the energy levels for some Hamiltonians in molecular physics. These are tri-atom molecules, the identical d-dimensional coupled harmonic oscillators and the dissipative linear-chain molecular model etc. The calculation is more direct and simpler than the usual diagonalization method for dynamic Hamiltonians.

scholarly journals Dynamics of the Oxygen, Carbon Dioxide, and Water Interaction across the Insect Spiracle

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
S. M. Simelane ◽  
S. Abelman ◽  
F. D. Duncan
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Differential Equations ◽  
Numerical Simulations ◽  
Ordinary Differential Equations ◽  
Continuous Time ◽  
Water Interaction ◽  
Stability And Instability ◽  
Respiratory Gases

This paper explores the dynamics of respiratory gases interactions which are accompanied by the loss of water through an insect’s spiracle. Here we investigate and analyze this interaction by deriving a system of ordinary differential equations for oxygen, carbon dioxide, and water vapor. The analysis is carried out in continuous time. The purpose of the research is to determine bounds for the gas volumes and to discuss the complexity and stability of the equilibria. Numerical simulations also demonstrate the dynamics of our model utilizing the new conditions for stability and instability.

scholarly journals Quantum relaxation in a system of harmonic oscillators with time-dependent coupling

2021 ◽  
Vol 477 (2248) ◽  
Author(s):  
Francisco Bento Lustosa ◽  
Samuel Colin ◽  
Santiago E. Perez Bergliaffa
Keyword(s):  
Numerical Simulations ◽  
Coarse Graining ◽  
Wave Theory ◽  
Harmonic Oscillators ◽  
Coarse Grained ◽  
Pilot Wave ◽  
The One ◽  
Simple Systems ◽  
Initial Distributions ◽  
Non Equilibrium

In the context of the de Broglie–Bohm pilot-wave theory, numerical simulations for simple systems have shown that states that are initially out of quantum equilibrium—thus violating the Born rule—usually relax over time to the expected | ψ | 2 distribution on a coarse-grained level. We analyse the relaxation of non-equilibrium initial distributions for a system of coupled one-dimensional harmonic oscillators in which the coupling depends explicitly on time through numerical simulations, focusing on the influence of different parameters such as the number of modes, the coarse-graining length and the coupling constant. We show that in general the system studied here tends to equilibrium, but the relaxation can be retarded depending on the values of the parameters, particularly to the one related to the strength of the interaction. Possible implications on the detection of relic non-equilibrium systems are discussed.

Dynamic Analysis and Design of LNG Tanks Considering Fluid Structure Interactions

2008 ◽  
Author(s):  
Y. P. Xiong ◽  
J. T. Xing
Keyword(s):  
Numerical Simulations ◽  
Sea Water ◽  
Dynamic Responses ◽  
Fluid Structure Interactions ◽  
Dynamic Design ◽  
Fluid Structure ◽  
Water Interaction ◽  
Lng Tank ◽  
Elastic Tank ◽  
Natural Characteristics

Following a general description and analysis of the fundamental criteria for the dynamic design concerning dynamic stiffness, strength and environment issues, it is considered that the natural characteristics of the dynamic system and the dynamic responses of the system subject to various dynamic loads are two key critical issues in the dynamic design. Therefore, for the dynamic design of a LNG tank filled with liquid and operated on seaway, it is necessary to accurately predict its natural characteristics and dynamic response considering fluid structure interactions. To address these two key issues in the dynamic design stage, the developed computer software based on a mixed displacement–pressure finite element model to complete fluid-structure interaction analysis is introduced. An integrated internal liquid-tank-external water interaction system investigated by numerical simulations is summarised to consider the two issues involving the dynamic design of LNG tanks. The five studied cases include: i) 50% filled LNG liquid in a fixed rigid tank, ii) elastic tank only, iii) 50% filled LNG liquid-elastic tank interaction, iv) empty elastic tank-external sea water interaction and v) internally 50% filled LNG liquid-elastic tank-external sea water interaction. The calculated results are compared to reveal the coupling effects on the dynamic design of LNG tanks. To further demonstrate the effects of the natural characteristics affected by different interactions on the dynamic responses involving the dynamic strength, stiffness and vibration environment problems considered in dynamic design, the numerical simulations of the studied systems subject to regular sea wave excitations and earthquake excitations are carried out. The dynamic displacements for stiffness analysis, the dynamic stress for strength analysis and vibration level for dynamic environment analysis are presented and discussed. Guidelines provided in this paper maybe useful for dynamic designs of LNG tank operating in complex marine environments.

Toward an alignment of the actin molecule within the actin filament

1983 ◽  
Vol 41 ◽  
pp. 450-451
Author(s):  
P.R. Smith ◽  
W.E. Fowler ◽  
U. Aebi
Keyword(s):  
Actin Filament ◽  
Diffraction Data ◽  
Quantitative Estimate ◽  
Molecular Model ◽  
Quantitative Comparison ◽  
Regulatory Proteins ◽  
Essential Information ◽  
X Ray ◽  
Maximum Resolution ◽  
Lack Of Information

An understanding of the specific interactions of actin with regulatory proteins has been limited by the lack of information about the structure of the actin filament. Molecular actin has been studied in actin-DNase I complexes by single crystal X-ray analysis, to a resolution of about 0.6nm, and in the electron microscope where two dimensional actin sheets have been reconstructed to a maximum resolution of 1.5nm. While these studies have shown something of the structure of individual actin molecules, essential information about the orientation of actin in the filament is still unavailable.The work of Egelman & DeRosier has, however, suggested a method which could be used to provide an initial quantitative estimate of the orientation of actin within the filament. This method involves the quantitative comparison of computed diffraction data from single actin filaments with diffraction data derived from synthetic filaments constructed using the molecular model of actin as a building block. Their preliminary work was conducted using a model consisting of two juxtaposed spheres of equal size.

Current Status of Solid-State X-Ray Systems

1985 ◽  
Vol 43 ◽  
pp. 158-161
Author(s):  
Martin Peckerar ◽  
Anastasios Tousimis
Keyword(s):  
Solid State ◽  
Electric Fields ◽  
Spectral Lines ◽  
Current Status ◽  
Mobile Charge ◽  
Electron Hole ◽  
X Ray ◽  
Sensing Systems ◽  
Transmission Electron ◽  
Electron Microscopes

Solid state x-ray sensing systems have been used for many years in conjunction with scanning and transmission electron microscopes. Such systems conveniently provide users with elemental area maps and quantitative chemical analyses of samples. Improvements on these tools are currently sought in the following areas: sensitivity at longer and shorter x-ray wavelengths and minimization of noise-broadening of spectral lines. In this paper, we review basic limitations and recent advances in each of these areas. Throughout the review, we emphasize the systems nature of the problem. That is. limitations exist not only in the sensor elements but also in the preamplifier/amplifier chain and in the interfaces between these components.Solid state x-ray sensors usually function by way of incident photons creating electron-hole pairs in semiconductor material. This radiation-produced mobile charge is swept into external circuitry by electric fields in the semiconductor bulk.

Exploration of cell wall architecture with the rapid-freeze deep-etch technique

1993 ◽  
Vol 51 ◽  
pp. 128-129
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Chris Hawes
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cell Biology ◽  
Molecular Model ◽  
Three Dimensional ◽  
Secretory Activity ◽  
Wall Structure ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

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