scholarly journals Grain size tuning of nanostructured Cu2O films through vapour phase supersaturation control and their characterization for practical applications

AIP Advances ◽  
2015 ◽  
Vol 5 (9) ◽  
pp. 097176 ◽  
Author(s):  
A. Anu ◽  
M. Abdul Khadar
Keyword(s):  
Grain Size ◽  
Vapour Phase ◽  
Practical Applications ◽  
Cu2o Films ◽  
Supersaturation Control

scholarly journals Towards practical applications of quantum emitters in boron nitride

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Koperski ◽  
K. Pakuła ◽  
K. Nogajewski ◽  
A. K. Dąbrowska ◽  
M. Tokarczyk ◽  
...  
Keyword(s):  
Optical Properties ◽  
Boron Nitride ◽  
Vapour Phase ◽  
Emission Characteristics ◽  
Vapour Phase Epitaxy ◽  
Practical Applications ◽  
Metalorganic Vapour Phase Epitaxy ◽  
Polydimethylsiloxane Films ◽  
Background Luminescence ◽  
Quantum Emitters

AbstractWe demonstrate quantum emission capabilities from boron nitride structures which are relevant for practical applications and can be seamlessly integrated into a variety of heterostructures and devices. First, the optical properties of polycrystalline BN films grown by metalorganic vapour-phase epitaxy are inspected. We observe that these specimens display an antibunching in the second-order correlation functions, if the broadband background luminescence is properly controlled. Furthermore, the feasibility to use flexible and transparent substrates to support hBN crystals that host quantum emitters is explored. We characterise hBN powders deposited onto polydimethylsiloxane films, which display quantum emission characteristics in ambient environmental conditions.

Effect of grain size distribution on the maximum and minimum void ratios of granular soils

2020 ◽  
Vol 17 (2) ◽  
pp. 26-33
Author(s):  
Jose Duque ◽  
William Mario Fuentes Lacouture ◽  
Jorge Andres Barros Ayala
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Granular Soil ◽  
Granular Soils ◽  
Size Distributions ◽  
Experimental Procedure ◽  
Practical Applications ◽  
Grain Size Distributions ◽  
Properties Of Soil

The maximum and minimum void ratios define the loosest and densest conditions of a granular soil. Correlations with some granulometric properties of soil are of interest for practical applications, but the experimental procedure to determine these variables can be time consuming. In this work the influence of the grain size distribution on the maximum and minimum void ratios is investigated. Twenty different granular soils with varying grain size distributions were prepared and tested. The experimental results, together with a compilation of 56 additional results reported in the literature, are statistically analysed. The analysis is conducted to examine the influence of some granulometric properties (D10, D30 and D60) on the maximum and minimum void ratios. As a result, some correlations considering the aforementioned variables are proposed. Subsequently, it is shown that the proposed correlations have better agreement with the experimental data than other proposals reported in the literature. The paper ends with some concluding remarks.

Effects of Relative High Density Preparation of Interfacial Coated Pb(Zr0.52Ti0.48)O3 on CaCu3Ti4O12 with Short Sintering Time on its Dielectric Properties

2012 ◽  
Vol 557-559 ◽  
pp. 1838-1843
Author(s):  
Rajabtabar Darvishi Ali ◽  
Wei Li Li ◽  
Sheikhnejad Bishe Ommeaymen ◽  
Li Dong Wang ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Grain Boundary ◽  
Relative Density ◽  
Sol Gel ◽  
Composite Particles ◽  
Composite Ceramics ◽  
Practical Applications ◽  
Cold Press ◽  
Sintering Time

Pb(Zr0.52Ti0.48)O3was coated on the surface of CaCu3Ti4O12particles that prepared using sol-gel method. Then the composite particles were sintered into composite ceramics using cold press with the two different pressures and pressing time to achieve sufficient higher relative density after sintering. Afterward, the composite particles were sintered into composite ceramics with various sintering time at the same temperature to reach smaller grain size and higher relative density. The results show that the ceramics are composed of Pb(Zr0.52Ti0.48)O3and CaCu3Ti4O12phases, and Pb(Zr0.52Ti0.48)O3phase is mainly exist at the grain boundary even the composite particles sintered for 2h before pellet making. The results exhibit when density of CaCu3Ti4O12/Pb(Zr0.52Ti0.48)O3composite ceramic is kept in higher level using this simple technology, not only The dissipation loss in these giant-dielectric constant materials was reduced to a considerable level of practical applications but also dielectric constant enhance to very high level in the large frequency range. The results show that the improvement of the dielectric loss and dielectric constant enhancing mainly comes from the increase in the density of the CaCu3Ti4O12/Pb(Zr0.52Ti0.48)O3composite ceramics using suitable pressure in cold press, suitable short sintering time that lead to smaller grain size and sufficient grain boundary.

Diamond Needles And Tips As Engineered Growth Shapes

1995 ◽  
Vol 416 ◽  
Author(s):  
K. A. Cherian ◽  
J. Litster ◽  
V. Rudolph ◽  
E. T. White
Keyword(s):  
Vapour Phase ◽  
Nucleation And Growth ◽  
Crystallographic Direction ◽  
Spiral Growth ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Diamond Nucleation ◽  
Practical Applications ◽  
Nucleation Sites ◽  
Double Spiral

ABSTRACTDiamond nucleation and growth by CFD were investigated to examine the possibility of engineering diamond growth shapes for practical applications. The results obtained include the following:a) Evidence supporting certain factors influencing nucleation - useful in controlling nucleation sites and nucleation density.b) Evidence for a double spiral growth mechanism operating on (111) faces under specific conditions - indicates the possibility of a new mechanism operating for diamond growth from the vapour phase, and the possibility of larger growth rates.c) Evidence for the enhanced growth in <100= crystallographic direction on a cubooctahedral crystal and its control by varying the process parameters – thus showing the possibility of obtaining diamond needles and tips as engineered growth shapes, for specific applications.

scholarly journals Study on the Physical Properties of Pulsed Laser Deposited Doped Copper Oxide (Cu2 O) Thin Films for Optical Device Applications

2020 ◽  
pp. 1-6
Author(s):  
Gurpreet Kaur ◽  
◽  
Anirban Mitra ◽  
Keyword(s):  
Thin Films ◽  
Absorption Coefficient ◽  
Room Temperature ◽  
Energy Gap ◽  
Visible Region ◽  
Pulsed Laser ◽  
Practical Applications ◽  
Wide Range ◽  
Cu2o Films ◽  
Cu2o Thin Films

Cuprous oxide, (Cu2O) is a promising p-type semiconductor, finds practical applications in a wide range of optoelectronic devices. In this paper, pulsed laser deposition technique is employed to deposit doped Cu2O thin films. The influence of doping of silver (Ag), aluminium (Al) and co-doping of (Ag+Al) in Cu2O thin films is illustrated. X-ray diffraction pattern depicts cubic crystal structure and polycrystalline nature of grown thin films, having small crystallite size (~50 nm). Atomic force microscopy (AFM) obtained surface images of the films portrait uniform grain morphology with low surface roughness. The room temperature optical characterizations of the thin films, the transmittance versus wavelength in the UV-Visible region exhibits low transmission values upto 10–20%, illustrates the large absorption coefficient (α), numerical values varying from 104 to 105cm-1 for doped Cu2O films. The large values of absorption coefficient facilitate the optical and photovoltaic applications of the doped Cu2O films. The addition of dopant species Ag and Al, the optical band gap is increased and it varies in the range of 2.65−2.84 eV. The increased energy gap is attributed to the substitution of Al and Ag ions for the oxygen ions reduce the width of valence band to widen the energy gap. The I−V characteristics plot obtained at room temperature indicates low electrical resistivity (ρ ~ 10-2Ω- cm) of the films. The obtained results are of high relevance and indicate potential applications of the grown thin films in semiconductor devices such as solar cells, photodetectors and optical sources

scholarly journals Influence of grain size distribution on dynamic shear modulus of sands

2017 ◽  
Vol 7 (1) ◽  
pp. 317-329 ◽  
Author(s):  
Ireneusz Dyka ◽  
Piotr E. Srokosz ◽  
Marcin Bujko
Keyword(s):  
Grain Size ◽  
Shear Modulus ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Soil Mechanics ◽  
Dynamic Shear Modulus ◽  
Cohesive Soils ◽  
Dynamic Shear ◽  
Bender Element ◽  
Practical Applications

AbstractThe paper presents the results of laboratory tests, that verify the correlation between the grain-size characteristics of non-cohesive soils and the value of the dynamic shear modulus. The problem is a continuation of the research performed at the Institute of Soil Mechanics and Rock Mechanics in Karlsruhe, by T. Wichtmann and T. Triantafyllidis, who derived the extension of the applicability of the Hardin’s equation describing the explicite dependence between the grain size distribution of sands and the values of dynamic shear modulus. For this purpose, piezo-ceramic bender elements generating elastic waves were used to investigate the mechanical properties of the specimens with artificially generated particle distribution. The obtained results confirmed the hypothesis that grain size distribution of non-cohesive soils has a significant influence on the dynamic shear modulus, but at the same time they have shown that obtaining unambiguous results from bender element tests is a difficult task in practical applications.

Controlled Atmosphere Thermal Treatment for Pyrochlore Phase Elimination of PMN-PT/CFO Prepared by Spark Plasma Sintering

2014 ◽  
Vol 975 ◽  
pp. 274-279 ◽  
Author(s):  
Diego Seiti Fukano Viana ◽  
José Antônio Eiras ◽  
William Junior Nascimento ◽  
Fabio Luiz Zabotto ◽  
Ducinei Garcia
Keyword(s):  
Grain Size ◽  
Spark Plasma Sintering ◽  
Single Phase ◽  
Magnetoelectric Effect ◽  
Pyrochlore Phase ◽  
Practical Applications ◽  
Plasma Sintering ◽  
Average Grain Size ◽  
Spark Plasma ◽  
Phase Elimination

Multiferroics are interesting materials which present more than one ferroic property and have a great potential for practical applications [,,]. In addition, the coupling of magnetic and electric properties, the magnetoelectric effect (ME), offers news possibilities to applications [2,]. The magnetoelectric effect can be observed in single-phase materials like LuFe2O4, BiFeO3, etc. [1,] or in composites like PMN-PT/CFO, BaTiO3/CoFe2O4, etc. The ME composites have advantages over single-phase materials. They are easier to fabricate, less expensive, and have a wider range of working temperatures than single-phase materials []. However, some parameters that enhance the ME response need to be optimized. These parameters are the composition, the microstructure (grain size, grain orientation) and sintering parameters [6]. Thus, this work attempts to create a synthesis protocol to prepare the ME composite PMN-PT/CFO by Spark Plasma Sintering (SPS) keeping the average grain size as small as possible.

Practical and Fundamental Studies of Nanocrystalline Composite Thin Films

1994 ◽  
Vol 356 ◽  
Author(s):  
Yang-Tse Cheng ◽  
Boqin Qiu ◽  
Simon Tung ◽  
J. P. Blanchard ◽  
G. Drew
Keyword(s):  
Grain Size ◽  
Wear Rate ◽  
Electron Probe ◽  
Friction And Wear ◽  
Composite Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Practical Applications ◽  
Transmission Electron ◽  
Nanocrystalline Composite

AbstractNanocrytslline composite films of Ag-Mo and Ag-Ni have been made by a co-deposition technique in UHV. The structure and composition have been studied by x-ray diffraction (XRD), transmission electron microscopy (TEM), and electron probe microanalysis (EPMA). For practical applications, the friction coefficient and wear rate were measured using a pin-on-plate machine for Ag-Mo composites deposited on steel. For fundamental studies, the hardness of the Ag-Ni composites deposited on oxidized Si wafers was measured using a nanoindenter. Experiments show that (1) reduction of friction and wear rate can be achieved using these nanocomposite coatings and (2) the hardness of the nanocomposites depends on the grain size. As the grain size of the Ag decreases from 100 to 10 nm, the hardness increases about 4 times.

Full-density nanocrystalline Fe–29Al–2Cr intermetallic consolidated from mechanically milled powders

1996 ◽  
Vol 11 (1) ◽  
pp. 72-80 ◽  
Author(s):  
L. He ◽  
E. Ma
Keyword(s):  
Grain Size ◽  
Mechanical Milling ◽  
Hot Forging ◽  
Full Density ◽  
Strengthening Effect ◽  
Practical Applications ◽  
Size Refinement ◽  
Sinter Forging ◽  
Average Grain Size ◽  
Milled Powders

Fe–29Al–2Cr powders with nanoscale grain sizes were produced by mechanical milling of prealloyed intermetallic powders. A consolidation procedure employing high-pressure, low strain rate hot forging (sinter-forging) has been developed to consolidate the powders into full-density compacts. The relative density and average grain size of the compact have been studied as a function of consolidation temperature at constant pressure. Fully dense compacts (>99.5% theoretical density) were produced at a relatively low temperature of 545°C with a pressure of 1.25 GPa. Transmission electron microscopy and x-ray diffraction analysis indicate that the average grain size has been maintained to the order of 30 nm in samples consolidated under these conditions. By using protective Ar atmosphere during mechanical milling and consolidation, contamination of oxygen and carbon in consolidated samples has been controlled to below a small fraction of an atomic percent. Microhardness tests of nanocrystalline Fe–29Al–2Cr samples indicate a significant strengthening effect due to grain size refinement and a monotonic hardness increase with decreasing residual porosity. Our work demonstrates the feasibility of using mechanically milled powders as the source of nanocrystalline materials for the production of fully dense, low-impurity, nanocrystalline bulk samples needed for reliable mechanical property measurements and practical applications.

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