Computer Simulation of the Equilibrium Morphology of Zirconia Nanocrystals

2015 ◽  
Vol 245 ◽  
pp. 3-7
Author(s):  
Andrey N. Chibisov
Keyword(s):  
Computer Simulation ◽  
Zirconium Oxide ◽  
Theoretical Calculations ◽  
Structure And Morphology ◽  
Cubic Phases ◽  
Equilibrium Morphology

The paper presents the theoretical calculations of the structure and morphology of ZrO2nanocrystals. The equilibrium morphology shapes of tetragonal and cubic nanocrystals were determined. It was shown that the equilibrium morphology was determined by an appropriate set of faces of tetragonal and cubic phases of zirconium oxide.

scholarly journals Planning Optimization of the Work Processes of Gas Cleaning Facilities of a Power Plant by Means of Mathematical Processing and Computer Simulation

2018 ◽  
Vol 41 ◽  
pp. 02011 ◽  
Author(s):  
Olesya Aksenova ◽  
Evgenia Nikolaeva
Keyword(s):  
Computer Simulation ◽  
Power Plant ◽  
Computer Modeling ◽  
Power Plants ◽  
Theoretical Calculations ◽  
Building Blocks ◽  
Design Stage ◽  
Work Processes ◽  
Gas Cleaning ◽  
Mathematical Processing

The article seeks to examine the efficiency of applying means of mathematical processing and computer modeling of the work processes of gas cleaning facilities of power plants to optimize the process of planning and designing of future power plant in operation. A way of solution of the gas outbursts cleaning problem at the stage of designing measures for the development of waste processing systems through mathematical processing of expected volumes of gas outbursts and computer simulation of individual pieces of equipment and working areas as a whole is offered. The authors present the results of the processing of the projected technological processes and the gas outbursts cleaning facilities in terms of E-networks and using mathematical processing in the application Simulink, which allows to build a model of the device and to carry out calculations on the screen using the library of building blocks. A 3D model of the gas cleaning facilities, which allows to visualize the technological process and to compare it with theoretical calculations at the design stage of the future power plant and, if necessary, make changes to the project, has been created by means of computer modeling.

Structure changes in the sol–gel systems of hydrated oxides

1998 ◽  
Vol 5 (3) ◽  
pp. 962-963 ◽  
Author(s):  
Yu. A. Gaponov ◽  
L. G. Karakchiev ◽  
N. Z. Lyakhov ◽  
B. P. Tolochko ◽  
K. Ito ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Temperature Region ◽  
Zirconium Oxide ◽  
Sol Gel ◽  
Structure And Morphology ◽  
Crystalline Product ◽  
Structure Changes ◽  
Hydrated Zirconium ◽  
Hydrated Aluminium Oxide ◽  
Hydrated Aluminium

Sols of hydrated aluminium oxide, hydrated zirconium oxide and their mixtures were investigated during the xerogel–amorphous-product–crystalline-product transition by SAXS using synchrotron radiation. In the different temperature regions certain changes in structure and morphology were observed. Some correlation between the characteristics of the initial sols and their mixtures (the size and shape of the pores) was observed. In the temperature region 298–1173 K the characteristics of the mixed sol are defined by the characteristics of the initial sols.

scholarly journals Mathematical Modelling and Computer Simulation Assist in Designing Non-traditional Types of Precipitators and Separators

2018 ◽  
Vol 8 (1) ◽  
pp. 441 ◽  
Author(s):  
Milan Bernat ◽  
Jaroslav Džmura ◽  
Renáta Bernátová ◽  
Ľubomr Žáčok ◽  
Jan Pavlovkin
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Computer Simulation ◽  
Computer Aided Design ◽  
Theoretical Calculations ◽  
Electrostatic Separation ◽  
Design Engineers ◽  
Computer Aided ◽  
Aided Design ◽  
Advanced Computer

<p>The article deals with the application of the method for mathematical modeling and simulation at solving some issues in the area of electrostatic technology. It focuses on the processes in electrostatic separation and precipitation. Computer simulation is highly required for equipment design and for their diagnostics in critical operating states using theoretical calculations and experimental data evaluation. The presented computer models may be applied both by project and design engineers using the most advanced computer-aided design of electrostatic technologies.</p>

Study on Minimum Teeth without Undercutting of Standard Involute Gears

2011 ◽  
Vol 199-200 ◽  
pp. 329-336 ◽  
Author(s):  
Jia Ning He ◽  
Wei Zhang ◽  
Hai Bin Zhang ◽  
Wu Xing Ma ◽  
Si Chen ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Theoretical Analysis ◽  
Mechanical Engineering ◽  
Theoretical Calculations ◽  
Theoretical Research ◽  
Involute Gears

In textbooks of mechanical engineering, rack has been mistakenly regarded as rack cutter so that minimum teeth without undercutting have been deduced, which has made people misunderstand undercut phenomenon more than 65 years. Theoretical research and computer simulation about undercut phenomenon are presented in this paper. Firstly, the theoretical analysis and calculation on minimum teeth without undercutting have been carried out, the rack cutter is used to infer minimum teeth without undercutting of standard involute gears, and correct minimum teeth without undercutting are get; And then computer simulation is applied to verify validity results of theoretical calculations, which not only corrects the long-standing mistakes about the traditional undercut phenomenon, but also provides the correct theoretical guidance for gears’ manufacturing.

XUV Absorption Spectra of Carbon Ions

1988 ◽  
Vol 102 ◽  
pp. 71-73
Author(s):  
E. Jannitti ◽  
P. Nicolosi ◽  
G. Tondello
Keyword(s):  
Absorption Spectra ◽  
Cross Section ◽  
Theoretical Calculations ◽  
Photoionization Cross Section ◽  
Carbon Ions

AbstractThe photoabsorption spectra of the carbon ions have been obtained by using two laser-produced plasmas. The photoionization cross-section of the CV has been absolutely measured and the value at threshold, σ=(4.7±0.5) × 10−19cm2, as well as its behaviour at higher energies agrees quite well with the theoretical calculations.

Resolving Crystallites in Zirconium Oxide Films

1969 ◽  
Vol 27 ◽  
pp. 140-141
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscope ◽  
Inelastic Scattering ◽  
Zirconium Oxide ◽  
Oxide Films ◽  
Optic Axis ◽  
Objective Lens ◽  
Microscope Objective ◽  
Linear Optic ◽  
A Current ◽  
Microscope Objective Lens

The optic axis of an electron microscope objective lens is usually assumed to be straight and co-linear with the mechanical center. No reason exists to assume such perfection and, indeed, simple reasoning suggests that it is a complicated curve. A current centered objective lens with a non-linear optic axis when used in conjunction with other lenses, leads to serious image errors if the nature of the specimen is such as to produce intense inelastic scattering.

Relative Intensities in ED Patterns From Thin Gold Films

1972 ◽  
Vol 30 ◽  
pp. 636-637
Author(s):  
R. H. Morriss ◽  
J. D. C. Peng ◽  
C. D. Melvin
Keyword(s):  
Theoretical Calculations ◽  
Diffraction Theory ◽  
Gold Films ◽  
Reasonable Accuracy ◽  
Experimental Conditions ◽  
Crystal Perfection ◽  
Heavy Atoms ◽  
Fine Focus ◽  
Convergent Beam ◽  
Beam Diffraction

Although dynamical diffraction theory was modified for electrons by Bethe in 1928, relatively few calculations have been carried out because of computational difficulties. Even fewer attempts have been made to correlate experimental data with theoretical calculations. The experimental conditions are indeed stringent - not only is a knowledge of crystal perfection, morphology, and orientation necessary, but other factors such as specimen contamination are important and must be carefully controlled. The experimental method of fine-focus convergent-beam electron diffraction has been successfully applied by Goodman and Lehmpfuhl to single crystals of MgO containing light atoms and more recently by Lynch to single crystalline (111) gold films which contain heavy atoms. In both experiments intensity distributions were calculated using the multislice method of n-beam diffraction theory. In order to obtain reasonable accuracy Lynch found it necessary to include 139 beams in the calculations for gold with all but 43 corresponding to beams out of the [111] zone.

Transition alpha structure in beta-isomorphous Nb-Hf alloys

1987 ◽  
Vol 45 ◽  
pp. 232-233
Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Miscibility Gap ◽  
Large Strains ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Diffuse Intensity ◽  
Metastable Form ◽  
The Matrix ◽  
Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

Effects of Higher-Order Laue Zone reflections on structure images

1993 ◽  
Vol 51 ◽  
pp. 450-451
Author(s):  
H. S. Kim ◽  
S. S. Sheinin
Keyword(s):  
Wave Vector ◽  
Theoretical Calculations ◽  
Reciprocal Lattice ◽  
Image Plane ◽  
Bloch Wave ◽  
Dynamical Theory ◽  
Higher Order ◽  
Lattice Image ◽  
Lattice Vector ◽  
Image Position

The importance of image simulation in interpreting experimental lattice images is well established. Normally, in carrying out the required theoretical calculations, only zero order Laue zone reflections are taken into account. In this paper we assess the conditions for which this procedure is valid and indicate circumstances in which higher order Laue zone reflections may be important. Our work is based on an analysis of the requirements for obtaining structure images i.e. images directly related to the projected potential. In the considerations to follow, the Bloch wave formulation of the dynamical theory has been used.The intensity in a lattice image can be obtained from the total wave function at the image plane is given by: where ϕg(z) is the diffracted beam amplitide given by In these equations,the z direction is perpendicular to the entrance surface, g is a reciprocal lattice vector, the Cg(i) are Fourier coefficients in the expression for a Bloch wave, b(i), X(i) is the Bloch wave excitation coefficient, ϒ(i)=k(i)-K, k(i) is a Bloch wave vector, K is the electron wave vector after correction for the mean inner potential of the crystal, T(q) and D(q) are the transfer function and damping function respectively, q is a scattering vector and the summation is over i=l,N where N is the number of beams taken into account.

Characterization of Modulated Structure Through Structure Images and their Computer Simulation

1990 ◽  
Vol 48 (1) ◽  
pp. 70-71
Author(s):  
Kiyomichi Nakai ◽  
Yusuke Isobe ◽  
Chiken Kinoshita ◽  
Kazutoshi Shinohara
Keyword(s):  
Computer Simulation ◽  
High Resolution ◽  
Spherical Aberration ◽  
High Resolution Electron Microscopy ◽  
Basic Mechanism ◽  
Objective Lens ◽  
Specimen Thickness ◽  
Transmitted Beam ◽  
Modulated Structure ◽  
Resolution Electron

Induced spinodal decomposition under electron irradiation in a Ni-Au alloy has been investigated with respect to its basic mechanism and confirmed to be caused by the relaxation of coherent strain associated with modulated structure. Modulation of white-dots on structure images of modulated structure due to high-resolution electron microscopy is reduced with irradiation. In this paper the atom arrangement of the modulated structure is confirmed with computer simulation on the structure images, and the relaxation of the coherent strain is concluded to be due to the reduction of phase-modulation.Structure images of three-dimensional modulated structure along <100> were taken with the JEM-4000EX high-resolution electron microscope at the HVEM Laboratory, Kyushu University. The transmitted beam and four 200 reflections with their satellites from the modulated structure in an fee Ni-30.0at%Au alloy under illumination of 400keV electrons were used for the structure images under a condition of the spherical aberration constant of the objective lens, Cs = 1mm, the divergence of the beam, α = 3 × 10-4 rad, underfocus, Δf ≃ -50nm and specimen thickness, t ≃ 15nm. The CIHRTEM code was used for the simulation of the structure image.

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