Search results for "imulation"
showing 10 items of 7271 documents
Validation of mathematical model for CZ process using small-scale laboratory crystal growth furnace
2018
The present material is focused on the modelling of small-scale laboratory NaCl-RbCl crystal growth furnace. First steps towards fully transient simulations are taken in the form of stationary simulations that deal with the optimization of material properties to match the model to experimental conditions. For this purpose, simulation software primarily used for the modelling of industrial-scale silicon crystal growth process was successfully applied. Finally, transient simulations of the crystal growth are presented, giving a sufficient agreement to experimental results.
Experimental and numerical investigation of laboratory crystal growth furnace for the development of model-based control of CZ process
2019
Abstract The presented study is focused on laboratory Czochralski crystal growth experiments and their mathematical modelling. The developed small-scale CZ crystal growth furnace is described as well as the involved automation systems: crystal radius detection by image recognition, temperature sensors, adjustable heater power and crystal pull rate. The CZ-Trans program is used to model the experimental results – transient, 2D axisymmetric simulation software primarily used for modelling of the industrial-scale silicon crystal growth process. Poor agreement with the experimental results is reached; however, the proven ability to perform affordable, small-scale experiments and successfully mo…
State-space formulation of scalar Preisach hysteresis model for rapid computation in time domain
2015
A state-space formulation of classical scalar Preisach model (CSPM) of hysteresis is proposed. The introduced state dynamics and memory interface allow to use the state equation, which is rapid in calculation, instead of the original Preisach equation. The main benefit of the proposed modeling approach is the reduced computational effort which requires only a single integration over the instantaneous line segment in the Preisach plane. Numerical evaluations of the computation time and model accuracy are provided in comparison to the CSPM which is taken as a reference model.
Simulations on time-of-flight ERDA spectrometer performance
2016
The performance of a time-of-flight spectrometer consisting of two timing detectors and an ionization chamber energy detector has been studied using Monte Carlo simulations for the recoil creation and ion transport in the sample and detectors. The ionization chamber pulses have been calculated using Shockley-Ramo theorem and the pulse processing of a digitizing data acquisition setup has been modeled. Complete time-of-flight–energy histograms were simulated under realistic experimental conditions. The simulations were used to study instrumentation related effects in coincidence timing and position sensitivity, such as background in time-of-flight–energy histograms. Corresponding measurement…
THE GYROTRON STARTUP SCENARIO IN THE SINGLE MODE TIME DEPENDENT APPROACH
2019
The paper explains how to solve the Gyrotron equation system in the Single Mode Time Dependent Approach. In particular, we point out problems encountered when solving these well-known equations. The starting current estimation approach a using time model is suggested. The solution has been implemented in the Matlab code, which is attached to the article.
Space‐vector state dynamic model of SynRM considering self‐ and cross‐saturation and related parameter identification
2020
This study proposes a state formulation of the space-vector dynamic model of the Synchronous Reluctance Motor (SynRM) considering both saturation and cross-saturation effects. The proposed model adopts the stator currents as state variables and has been theoretically developed in both the rotor and stator reference frames. The proposed magnetic model is based on a flux versus current approach and relies on the knowledge of 11 parameters. Starting from the definition of a suitable co-energy variation function, new flux versus current functions have been initially developed, based on the hyperbolic functions and, consequently, the static and dynamic inductance versus current functions have be…
The ensemble switch method and related approaches to obtain interfacial free energies between coexisting phases from simulations: a brief review
2015
The accurate estimation of the excess free energy due to an interface between coexisting phases of a model system by computer simulation often is a challenging task. We review here two methods, whi...
MD Simulation Investigation on the Binding Process of Smoke-Derived Germination Stimulants to Its Receptor
2019
Karrikins (KARs) are a class of smoke-derived seed germination stimulants with great significance in both agriculture and plant biology. By means of direct binding to the receptor protein KAI2, the compounds can initiate the KAR signal transduction pathway, hence triggering germination of the dormant seeds in the soil. In the research, several molecular dynamics (MD) simulation techniques were properly integrated to investigate the binding process of KAR1 to KAI2 and reveal the details of the whole binding event. The calculated binding free energy, -7.00 kcal/mol, is in good agreement with the experimental measurement, -6.83 kcal/mol. The obtained PMF profile indicates the existence of thre…
Computational Study of the Effect of Glyoxal–Sulfate Clustering on the Henry’s Law Coefficient of Glyoxal
2014
We have used quantum chemical methods to investigate the molecular mechanism behind the recently reported ( Kampf , C. J. ; Environ. Sci. Technol . 2013 , 47 , 4236 - 4244 ) strong dependence of the Henry's law coefficient of glyoxal (C2O2H2) on the sulfate concentration of the aqueous phase. Although the glyoxal molecule interacts only weakly with sulfate, its hydrated forms (C2O3H4 and C2O4H6) form strong complexes with sulfate, displacing water molecules from the solvation shell and increasing the uptake of glyoxal into sulfate-containing aqueous solutions, including sulfate-containing aerosol particles. This promotes the participation of glyoxal in reactions leading to secondary organic…
Spectroscopic tools for remote sensing of greenhouse gases CH4, CF4 and SF6
2003
International audience; Highly symmetrical molecules such as CH4, CF4 or SF6 are known to be atmospheric pollutants and greenhouse gases. High-resolution spectroscopy in the infrared is particularly suitable for the monitoring of gas concentration and radiative transfers in the earth's atmosphere. This technique requires extensive theoretical studies for the modeling of the spectra of such molecules (positions, intensities and shapes of absorption lines). Here, we have developed powerful tools for the analysis and the simulation of absorption spectra of highly symmetrical molecules. These tools have been implemented in the spherical top data system (STDS) and highly-spherical top data syste…