scholarly journals INFLUENCE OF POLYMORPHIC TRANSFORMATIONS ON ANISOTROPY OF THE SURFACE ENERGY AND THE WORK FUNCTION OF THE ELECTRON OF LITHIUM

2021 ◽  
pp. 439-446
Author(s):  
Ирина Гусейновна Шебзухова ◽  
Людмила Павловна Арефьева
Keyword(s):  
Experimental Data ◽  
Surface Layer ◽  
Surface Energy ◽  
Crystal Lattice ◽  
Work Function ◽  
Analytical Relationship ◽  
Polymorphic Transformations ◽  
Calculation Results ◽  
Limiting Temperatures ◽  
Good Agreement

На базе электронно-статистического метода показана связь и проведена оценка поверхностной энергии и работы выхода электрона граней кристаллов лития с учетом дисперсионного, поляризационного и осцилляционного взаимодействия атомов поверхностного слоя. Считалось, что кристаллическая решетка не имеет дефектов. Модифицированы выражения поправок и аналитического соотношения, связывающего работу выхода электрона и поверхностную энергию с учетом типа кристаллической решетки и ориентации граней. Рассчитана работа выхода электрона и поверхностная энергия гладких граней при предельных температурах существования полиморфных фаз лития. Установлено влияние полиморфных превращений и температуры на анизотропию. Температурный коэффициент работы выхода электрона бездефектного кристалла положителен и составляет порядка 0,1-1 мэВ. Результаты расчетов хорошо согласуются с экспериментальными данными для поликристаллов. On the basis of the electronic-statistical method, a relationship is obtained and the surface energy and the work function of the electron of the faces of lithium crystals are estimated, taking into account the dispersion, polarization, and oscillatory interactions of the atoms of the surface layer. It was assumed that the crystal lattice has no defects. The expressions for the corrections and an analytical relationship between the work function of the electron and the surface energy are modified taking into account the type of the crystal lattice and the orientation of the faces. The work function of the electron and the surface energy of smooth faces are calculated at the limiting temperatures of the existence of polymorphic lithium phases. The influence of polymorphic transformations and temperature on the anisotropy is established. The temperature coefficient of the work function of an electron in a defect-free crystal is positive and amounts to about 0,1-1 meV. The calculation results are in good agreement with the experimental data for polycrystals.

scholarly journals Анизотропия поверхностной энергии и работы выхода электрона IIВ металлов

2019 ◽  
Vol 89 (2) ◽  
pp. 306
Author(s):  
И.Г. Шебзухова ◽  
Л.П. Арефьева
Keyword(s):  
Experimental Data ◽  
Surface Energy ◽  
Work Function ◽  
Statistical Method ◽  
Electron Work Function ◽  
Method Of Calculation ◽  
Cadmium Zinc ◽  
Good Agreement

AbstractOn the basis of electron-statistical method of calculation of the surface energy of metals, a technique for estimating the electron work function of hexagonal and rhombohedral metallic crystals has been developed. This technique relates surface energy to work function and can thus be applied to estimate the surface energy of crystal faces from experimental data for a work function. Computations have been made for cadmium, zinc, and mercury macrocrystals. The temperature and orientation dependences of both quantities have been constructed. Our results are in good agreement with literature experimental data.

Surface properties of rare-earth metals and the effects of their substitutional doping on work function of the W(110) surface

2019 ◽  
Vol 87 (1) ◽  
pp. 11301
Author(s):  
Jian Wang ◽  
Zhijun He ◽  
Jin Nie ◽  
Xiaoxiao Sun ◽  
Yu Han ◽  
...  
Keyword(s):  
Experimental Data ◽  
Rare Earth ◽  
Surface Energy ◽  
Work Function ◽  
First Principles ◽  
Rare Earth Metals ◽  
Thermionic Emission ◽  
First Principles Calculations ◽  
Substitutional Doping ◽  
Good Agreement

The surface energy and work function of rare-earth metals (from La to Lu) are studied by the first principles calculations. The obtained values are in good agreement with available experimental data. Motivated by enhanced thermionic emission performance resulting from low work function, we substitutionally doped the rare-earth atoms on W(110) surface to improve the work function. The results show that rare-earth atoms doping can significantly reduce the work function of the W(110) surface, and Eu, Pr and Nd are the three best candidates for work function reduction.

Simulation on Coal Devolatilization Combined a Multi-Step Kinetic Model with Chemkin Software

2012 ◽  
Vol 608-609 ◽  
pp. 1375-1382
Author(s):  
Rui Zhang ◽  
Qin Hui Wang ◽  
Zhong Yang Luo ◽  
Meng Xiang Fang
Keyword(s):  
Experimental Data ◽  
Kinetic Model ◽  
Intermediate Product ◽  
Coal Combustion ◽  
Model Complexity ◽  
Coal Pyrolysis ◽  
Simple Application ◽  
Calculation Results ◽  
Simulation Results ◽  
Good Agreement

As the first step in coal combustion and gasification, coal devolatilization has significant effect on reaction process. Previous coal devolatilization models have some disadvantages, such as poor flexibility, model complexity, and requirement of characterization parameters. Recently, Sommariva et al. have proposed a multi-step kinetic model of coal devolatilization. This model avoids the disadvantages mentioned above and can predict elemental composition of tar and char. In this paper, the mechanism of this model has been revised for simple application to Chemkin. Revision method is that some reactions are split into more reactions by using one pseudo-intermediate-product to replace several final products. Simulation results show that calculation results from revised mechanism compare quite well with that from original mechanism and have good agreement with experimental data. The revised mechanism is accurate and can be applied to Chemkin very easily, which gives it wide application to simulation of coal pyrolysis, gasification and combustion.

Pemuatan listrik bipolar untuk partikel aerosol

2018 ◽  
Vol 4 (3) ◽  
pp. 287
Author(s):  
Heru Setyawan
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Ion Mobility ◽  
Opposite Sign ◽  
Aerosol Particles ◽  
Calculation Results ◽  
Two Parameters ◽  
Diffusion Charging ◽  
Fuchs Theory ◽  
Good Agreement

Bipolar diffusion charging of aerosol particles has been studied theoretically using Fuchs theory. Experimental data measured by several researchers available in the published literature were used to verify the calculation results. The calculation results show that Fuchs theory has been successfully used to predict the experimental data of the charging probability of submicron aerosol particles. The combination probability of ion-particle increases with the increase of particle size, both for particle and ion with the same sign and those with the opposite sign. However the combination probability is larger if the charges of particle and ion are of the opposite sign. Generally, Fuchs theory is not too easy to deal with due to the ill-defined of all parameters used, namely ion mass and ion mobility. These cause many possibilities of parameter combination that can give a good agreement with experimental data. Thus, in order to interpret the experimental results properly, the two parameters should be measured simultaneously with aerosol measurements.Keywords: Aerosol, Bipolar Charging, Combination ProbabilityAbstrakPemuatan listrik difusi bipolar partikel aerosol telah dipelajari secara teoritis menggunakan teori Fuchs. Sebagai verifikasi digunakan data eksperimen beberapa peneliti yang tersedia dalam literatur yang telah dipublikasikan. Hasil perhitungan menunjukkan bahwa teori Fuchs berhasil memprediksi dengan baik data eksperimen probabilitas pemuatan listrik partikel aerosol dalam rentang ukuran partikel berukuran submikron. Probabilitas penggabungan ion-partikel semakin besar dengan semakin besarnya ukuran partikel, baik untuk partikel dan ion yang memiliki tanda yang berlawanan maupun yang memiliki tanda yang sama. Akan tetapi, probabilitas penggabungan untuk partikel dan ion yang memiliki tanda yang berlawanan memiliki nilai yang lebih besar. Pada umumnya teori Fuchs tidak terlalu mudah untuk digunakan yang disebabkan oleh tidak terdefinisikannya dengan baik semua parameter yang digunakan, yaitu  massa ion dan mobilitas ion. Hal ini mengakibatkan banyak kemungkinan kombinasi parameter yang bisa menghasilkan kesesuaian yang bagus dengan data hasil pengukuran. Jadi, agar dapat menginterpretasikan hasil pengukuran dengan tepat, kedua besaran tersebut harus diukur secara serempak denganpengukuran aerosol.Kata Kunci: Aerosol, Pemuatan Listrik Bipolar, Probabilitas Penggabungan

Prediction of Solid-Liquid Interface Stability and Dendritic Growth in Multi-Component Alloys with Calphad Method

2005 ◽  
Vol 475-479 ◽  
pp. 2721-2724
Author(s):  
Rui Jie Zhang ◽  
Zhi He ◽  
Wan Qi Jie
Keyword(s):  
Experimental Data ◽  
Present Method ◽  
Dendritic Growth ◽  
Calphad Method ◽  
Liquid Interface ◽  
Interface Stability ◽  
Calculation Results ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Good Agreement

A method to predict the solid-liquid interface stability and the constrained dendrite growth of multi-component alloys was developed based on the Calphad method. The method was applied to several industrial Al-Si-Mg alloys, and the predicted results were compared with some former experimental data. The good agreement between the calculation results and the experimental data demonstrates the superiority of the present method to the classical one based on constant parameter assumptions.

Theoretical investigations of 63Cu2+ orbital Knight shifts for YBa2Cu4O8

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542007 ◽  
Author(s):  
Min-Quan Kuang ◽  
Shao-Yi Wu ◽  
Zhi-Hong Zhang ◽  
Xian-Fen Hu
Keyword(s):  
Experimental Data ◽  
Experimental Verification ◽  
High Order ◽  
Order Perturbation ◽  
Theoretical Investigations ◽  
Calculation Results ◽  
Knight Shifts ◽  
Good Agreement

The temperature-independent orbital Knight shifts for the orthorhombic [Formula: see text] site in [Formula: see text] (Y124) are investigated by utilizing the high order perturbation formulae of these parameters for a [Formula: see text] ion situated into orthorhombically elongated octahedra. The calculation results are in good agreement with the experimental data. The moderate quasi-axial anisotropies of the Knight shifts are ascribed to the elongation distortion of the four-fold coordinated Cu[Formula: see text] site. The [Formula: see text] factors are also theoretically calculated in a uniform way for further experimental verification.

scholarly journals ANISOTROPY OF THE SURFACE OF CUBIC BODY-CENTERED CRYSTAL LATTICES

2021 ◽  
Vol 18 (1) ◽  
pp. 9-15
Author(s):  
V.M. Yurov ◽  
Keyword(s):  
Surface Layer ◽  
Surface Energy ◽  
Work Function ◽  
Single Crystals ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Electron Work Function ◽  
Fundamental Parameter ◽  
Statistical Calculation ◽  
Crystal Lattices

In the work of Shebzukhova and Arefieva, by the method of electronic-statistical calculation of the anisotropy of the surface energy of metals, a method for estimating the work function of electrons from a metal was determined. The surface energy and electron work function of four main faces of cadmium and zinc crystals and five faces of mercury are estimated. In the work of Bokarev, the anisotropy of the surface energy of single crystals was calculated from the model of coordination melting of crystals. Based on experimental studies and theoretical calculations, it is shown that the model of coordination melting of crystals unambiguously links the physicochemical properties of the surface of single crystals with their crystal structure. In our proposed empirical model, not only the anisotropy is calculated, but also the thickness of the surface layer of the metal. It is shown that the thickness of the surface layer is determined by one fundamental parameter - the molar (atomic) volume, which periodically changes in accordance with the table of D.I. Mendeleev. It is shown in the work that the work function of electrons changes proportionally with a change in the surface energy of the metal. This means that the device we have developed can be used to measure the state of the metal surface and its anisotropy.

scholarly journals Theoretical Model of Droplet Wettability on a Low-Surface-Energy Solid under the Influence of Gravity

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Yukihiro Yonemoto ◽  
Tomoaki Kunugi
Keyword(s):  
Experimental Data ◽  
Contact Angle ◽  
Theoretical Model ◽  
Surface Energy ◽  
Binary Mixture ◽  
Liquid Surface ◽  
Droplet Radius ◽  
Low Surface Energy ◽  
Geometrical Information ◽  
Good Agreement

The wettability of droplets on a low surface energy solid is evaluated experimentally and theoretically. Water-ethanol binary mixture drops of several volumes are used. In the experiment, the droplet radius, height, and contact angle are measured. Analytical equations are derived that incorporate the effect of gravity for the relationships between the droplet radius and height, radius and contact angle, and radius and liquid surface energy. All the analytical equations display good agreement with the experimental data. It is found that the fundamental wetting behavior of the droplet on the low surface energy solid can be predicted by our model which gives geometrical information of the droplet such as the contact angle, droplet radius, and height from physical values of liquid and solid.

scholarly journals Melting of micro/nanoparticles considering anisotropy of surface energy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. M. Yang ◽  
M. W. Chen ◽  
G. J. Zheng ◽  
Z. D. Wang
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Surface Energy ◽  
Asymptotic Solution ◽  
Melting Temperature ◽  
Asymptotic Method ◽  
Crystal Orientations ◽  
Nanoparticle Melting ◽  
Effect Of Surface ◽  
Good Agreement

AbstractThe effect of surface energy on the melting of micro/nanoparticles is studied using the asymptotic method. The asymptotic solution of the dynamic model for micro/nanoparticle melting reveals the dependence of the particle melting temperature on the particle size and the anisotropy of surface energy. Specifically, as the particle radius decreases, the isotropic surface energy reduces the melting temperature and accelerates the interface melting of the particle. Along certain crystal orientations, the anisotropy of surface energy enhances the melting temperature of the micro/nanoparticles, whereas depresses the melting temperature of the micro/nanoparticle along other crystal orientations. The anisotropy of surface energy enhances the melting speed of the micro/nanoparticles along certain crystal orientations, whereas reduces the melting speed of the micro/nanoparticles along other crystal orientations. The result of the asymptotic solution is in good agreement with the experimental data.

Tools for Estimating Resonant Stresses in Turbine Blades

2007 ◽  
Author(s):  
A. M. Sipatov ◽  
N. V. Gladisheva ◽  
V. G. Avgustinovich ◽  
I. A. Povishev
Keyword(s):  
Experimental Data ◽  
Turbine Blades ◽  
Aircraft Engine ◽  
Mode Shapes ◽  
Ansys Software ◽  
Factors Affecting ◽  
Gas Dynamic ◽  
Calculation Results ◽  
Main Factors ◽  
Good Agreement

The problem of obtaining adequate aerodynamical boundary conditions for an analyzed blade is important to predict resonant stresses. According to this, three different CFD approaches of stator-rotor modeling have been investigated for obtaining gas dynamic loading: 1. 3D averaged and then quasi-3D unsteady calculations. 2. Fully 3D unsteady calculations using commercial CFX solver. 3. Fully 3D unsteady calculations using the in-house solver. To carry out 3D structural analysis the ANSYS software and our subroutines have been applied. The methodology to estimate damper ratio for the different mode shapes and mode numbers has been developed. As a result, the tools to predict the resonant stress have been created where we tried to take into account all main factors affecting resonant stress level. The HPT first stage blade of a modern aircraft engine was chosen as an example of using our tools for prediction of resonant stresses level. A comparison of experimental data and obtained calculation results showed good agreement.

Sign in / Sign up

Export Citation Format

Share Document