scholarly journals Эффекты Холла и Зеебека в тонких пленках висмута на подложке из слюды в диапазоне температур 77-300 K

2019 ◽  
Vol 53 (5) ◽  
pp. 597
Author(s):  
В.А. Комаров ◽  
В.М. Грабов ◽  
А.В. Суслов ◽  
Н.С. Каблукова ◽  
М.В. Суслов
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
Size Effect ◽  
Block Size ◽  
Hole Mobility ◽  
Seebeck Coefficients ◽  
Bismuth Single Crystal ◽  
Electron Contribution ◽  
Bismuth Films ◽  
Classical Size

AbstractThe effects of film thickness and block size on the Hall and Seebeck effects in bismuth films on mica substrates are analyzed using experimental data. A preferential decrease in the electron contribution with a decrease in the film thickness and a preferential decrease in the hole contribution with a decrease in the block size are established. The Hall and Seebeck coefficients are calculated using the classical size effect with regard to carrier scattering at block boundaries and anisotropy of the properties of carriers. In the calculation, the electron and hole mobility components and their concentration in a bismuth single crystal are used and the crystallographic orientation of the film crystal are taken into account. The results of the calculation are in good agreement with the experimental data. It is concluded that the value and sign of the Hall and Seebeck coefficients in bismuth films are determined by the competition of the classical size effect and scattering at block boundaries.

scholarly journals Experimental data on strength properties of mussel shell concretes and specimen size effect

Data in Brief ◽  
2021 ◽  
Vol 35 ◽  
pp. 106954
Author(s):  
Costas A. Anagnostopoulos ◽  
Denis Cabja ◽  
Chrysi A. Papadimitriou
Keyword(s):  
Experimental Data ◽  
Size Effect ◽  
Strength Properties ◽  
Specimen Size ◽  
Mussel Shell

scholarly journals Analytical Formula for the Ratio of Central to Minimum Film Thickness in a Circular EHL Contact

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 80 ◽  
Author(s):  
Petr Sperka ◽  
Ivan Krupka ◽  
Martin Hartl
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
Analytical Formula ◽  
Numerical Calculations ◽  
Constant Ratio ◽  
Viscosity Coefficients ◽  
Wide Range ◽  
Minimum Film Thickness ◽  
Film Parameter ◽  
Ehl Contact

Prediction of minimum film thickness is often used in practice for calculation of film parameter to design machine operation in full film regime. It was reported several times that majority of prediction formulas cannot match experimental data in terms of minimum film thickness. These standard prediction formulas give almost constant ratio between central and minimum film thickness while numerical calculations show ratio which spans from 1 to more than 3 depending on M and L parameters. In this paper, an analytical formula of this ratio is presented for lubricants with various pressure–viscosity coefficients. The analytical formula is compared with optical interferometry measurements and differences are discussed. It allows better prediction, compared to standard formulas, of minimum film thickness for wide range of M and L parameters.

A New Postulation of Viscosity and Its Application in Computation of Film Thickness in TFL1

2002 ◽  
Vol 124 (4) ◽  
pp. 811-814 ◽  
Author(s):  
Chaohui Zhang ◽  
Jianbin Luo ◽  
Shizhu Wen
Keyword(s):  
Thin Film ◽  
Experimental Data ◽  
Film Thickness ◽  
Solid Surface ◽  
Contact Area ◽  
Elastohydrodynamic Lubrication ◽  
Thin Film Lubrication ◽  
Lubrication Film ◽  
Viscosity Modification ◽  
Film Lubrication

In this paper, a viscosity modification model is developed which can be applied to describe the thin film lubrication problems. The viscosity distribution along the direction normal to solid surface is approached by a function proposed in this paper. Based on the formula, lubricating problem of thin film lubrication (TFL) in isothermal and incompressible condition is solved and the outcome is compared to the experimental data. In thin film lubrication, according to the computation outcomes, the lubrication film thickness is much greater than that in elastohydrodynamic lubrication (EHL). When the velocity is adequately low (i.e., film thickness is thin enough), the pressure distribution in the contact area is close to Hertzian distribution in which the second ridge of pressure is not obvious enough. The film shape demonstrates the earlobe-like form in thin film lubrication, which is similar to EHL while the film is comparatively thicker. The transformation relationships between film thickness and loads, velocities or atmosphere viscosity in thin film lubrication differ from those in EHL so that the transition from thin film lubrication to EHL can be clearly seen.

scholarly journals A Quantitative Determination of Minimum Film Thickness in Elastohydrodynamic Circular Contacts

2021 ◽  
Author(s):  
Wassim Habchi ◽  
Philippe Vergne
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Numerical Model ◽  
Film Thickness ◽  
Quantitative Determination ◽  
Excellent Agreement ◽  
Operating Conditions ◽  
Pure Rolling ◽  
Minimum Film Thickness

Abstract The current work presents a quantitative approach for the prediction of minimum film thickness in elastohydrodynamic lubricated (EHL) circular contacts. In contrast to central film thickness, minimum film thickness can be hard to accurately measure, and it is usually poorly estimated by classical analytical film thickness formulae. For this, an advanced finite-element-based numerical model is used to quantify variations of the central-to-minimum film thickness ratio with operating conditions, under isothermal Newtonian pure-rolling conditions. An ensuing analytical expression is then derived and compared to classical film thickness formulae and to more recent similar expressions. The comparisons confirmed the inability of the former to predict the minimum film thickness, and the limitations of the latter, which tend to overestimate the ratio of central-to-minimum film thickness. The proposed approach is validated against numerical results as well as experimental data from the literature, revealing an excellent agreement with both. This framework can be used to predict minimum film thickness in circular elastohydrodynamic contacts from knowledge of central film thickness, which can be either accurately measured or rather well estimated using classical film thickness formulae.

Manifestations of the quantum size effect in the electrochemical behaviour of thin bismuth films

1985 ◽  
Vol 196 (1) ◽  
pp. 157-165 ◽  
Author(s):  
A.M. Skundin ◽  
A.Z. Zaidenberg ◽  
A.M. Brodsky ◽  
V.S. Bagotzky
Keyword(s):  
Size Effect ◽  
Electrochemical Behaviour ◽  
Quantum Size Effect ◽  
Quantum Size ◽  
Bismuth Films

Interaction of Tops of Domains in Metal Nano of the Film

2019 ◽  
Vol 945 ◽  
pp. 771-775 ◽  
Author(s):  
V.P. Panaetov ◽  
Denis B. Solovev
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Film Thickness ◽  
Magnetic Structure ◽  
Domain Walls ◽  
Magnetic Moments ◽  
Ferromagnetic Film ◽  
Easy Magnetization ◽  
Electron Transmission ◽  
Transmission Microscope

Ferromagnetic film can be a matrix for recording information with the help of magnetic moments of electrons. The study of the processes of changing the magnetic structure in an electron-transmission microscope makes it possible to investigate micro magnetic phenomena. In this paper, we investigate the interaction between the vertices of neighboring regions. It is shown how the magnetic structure of the vertices of the domains changes as they approach each other with the help of an increasing constant magnetic field applied along the axis of easy magnetization. The distance was measured between the vertices of the domains. The schemes of distribution of the magnetization vectors between interacting vertices are shown. These schemes are made from experimental images of the magnetic structure. The distances between domain vertices and domain walls were compared on the basis of experimental data. The film thickness is 50 nm; the structure is Ni0.83-Fe0.17. The films were obtained by the method proposed by us. From the experimental results it follows that the interaction of the domain walls is observed at a distance of 20 microns and the interaction of the domain vertices is manifested at a distance of 100 μm.

The Influence of Quantizing Magnetic Field on The Magnetic Susceptibilities in Ultra Thin Films of Dilute Magnetic Materials

1993 ◽  
Vol 313 ◽  
Author(s):  
Kamakhya P Ghatak ◽  
S. N. Biswas
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Thin Films ◽  
Theoretical Analysis ◽  
Film Thickness ◽  
Magnetic Materials ◽  
Ultrathin Films ◽  
Surface Concentration ◽  
Magnetic Susceptibilities ◽  
Quantizing Magnetic Field

ABSTRACTIn this paper we have studied the dia and paramagnetic susceptibilities of the holes in ultrathin films of dilute magnetic materials in the presence of a quantizing magnetic field and compared the same with that of the bulk specimens under magnetic quantization for the purpose of relative comparison. It is found, taking Hg1−xMnxTe and Cd1−xMnxSe as examples, that both the susceptibilities increase with decreasing film thickness and increasing surface concentration in oscillatory Manners. The numerical values of the susceptibilities in ultrathin films of dilute magnetic materials are greater than that of the bulk and the theoretical analysis is in agreement with the experimental data as reported elsewhere.

scholarly journals The granule size distribution influence in nanocomposites on optical and magnetooptical spectra

2018 ◽  
Vol 185 ◽  
pp. 02009 ◽  
Author(s):  
Alexey Yurasov ◽  
Elena Gan’shina ◽  
Alexey Sokolov ◽  
Nikita Granovsky ◽  
Daria Zazymkina
Keyword(s):  
Size Effect ◽  
Size Distribution ◽  
Granule Size ◽  
Near Ir ◽  
Electron Transitions ◽  
Classical Size

We have investigated the size effect (quasi-classical size effect) in nanocomposites. It was shown that the size effect can change the amplitude, form and sign of the optical and magnetooptical spectra. We have deduced formulas for size effect and discussed the applications of the distributions for corrected description of optical and magnetooptical properties with regard to the granule size effect. It is very important to consider the distribution on the granule size in size effect. This fact allows to describe optical and magnetooptical spectra of nanocomposites better, especially in near IR due to intraband electron transitions. We have deduced formulas for size effect and discussed applications of the distributions for corrected description of optical and magnetooptical properties with regard to the effect of the granule size.

Rheology of Lubricants in Real Bearing Contacts

1975 ◽  
Vol 97 (2) ◽  
pp. 228-235 ◽  
Author(s):  
J. W. Kannel ◽  
S. S. Bupara
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
Dynamic Pressure ◽  
Analytical Treatment ◽  
Experimental Conditions ◽  
X Ray ◽  
Lubricated Contacts ◽  
Fundamental Understanding ◽  
Machine Elements ◽  
Contact Pressures

Experimental traction-slip and lubricant film-thickness data have been determined for selected lubricants to provide information for use in conjunction with the design of lubricated machine elements. The traction-slip experiments were performed using a rolling-disk rheometer which closely simulates those conditions existent in real lubricated contacts; the film-thickness data were obtained using an X-ray technique. The range of experimental conditions included two rolling speeds (5000 and 10,000 rpm), several contact pressures [(690 – 2400 MN/m2) (100 to 350 ksi)], and three temperatures [(338, 366 and 423 K) (150, 200, and 300 F)]. The slip conditions imposed on the lubricants ranged as high as 6 m/s (1200 fpm) which is equivalent to a shear rate of approximately 0.5 × 108 sec−1. Interpretative analyses have been developed to infer basic lubricant properties from the experimental data. These analyses include time delay parameters and “dynamic” pressure-viscosity parameters. The analytical treatment of the data provides: (1) a generalization of the experimental data to apply over a wider range of conditions than those actually covered, and (2) a basis for comparing lubricants and obtaining a more fundamental understanding of lubricant behavior.

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