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Showing 1 to 20 of 108 for “"lattice parameters"”.
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Pegmatitic muscovites: effect of composition on optical and lattice parameters
… both the optical properties and the unit cell parameters. The results of this study indicate refractive indices increase to the extent Fe and Ti constitute the octahedral cations, and to the extent OH rather than F coordinates to these cations. The optic angle 2VX decreases nearly linearly with …
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Use of neutron absorbers for the experimental determination of lattice parameters in subcritical assemblies.
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1966.
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Determination of Phase Fraction, Lattice Parameters and Crystallite Size in Mechanically Alloyed Fe-Ni Powders
… fcc phases in the alloys and to determine the lattice parameters and crystallite size. The main objective of this project is to study how the milling at low temperatures affects the region of two phase co-existence, phase structure and crystallite size. It was found that the composition ranges …
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Relationship between the chemical composition, lattice parameters, and optical properties of andalusite and its isostructural analogs
The refractive indices for light vibrating along the a, b, and c cell edges -- symbols na, nb, and nc - were measured for 20 andalusite-kanonaite solid solutions ranging from relatively pure andalusite (Al₂SiO₅) to about 62 mole percent kanonaite (MnAlSi0₅). Of the 20 crystals, 8 contained …
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X-ray diffraction study of compressed solid argon and krypton
… and applied both to obtain very precise x-ray lattice parameters along the melting curves of solid argon and solid krypton and to measure changes in vacancy concentrations along quasi-isochores for both these substances. The uncertainty of the lattice parameters obtained along melting was …
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Solid solubility of silver in the superconducting YBa₂Cu₃O compound
… and secondary ion mass spectrometry (SIMS). The lattice parameters were precisely determined by a rigorous X-ray diffraction method and by using a USGS computer program which uses an iterative least square solution to calculate the lattice parameters and the standard deviations. The final …
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X-ray study of the stacking fault density near the hardness maximum of the Au-Ag-Pd system
… with the existing hardness map. In addition, lattice parameters, stacking fault densities, and spacing change fractions have been determined for those alloys. The lattice parameters were found to deviate negatively from Vegard's Law. For the alloys studied, the maximum deviation of 0.0091 A …
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Thermal vacancies in HCP helium-4
… between 18.17 and 20.9 cm$\sp3$/mole. Absolute lattice parameters at low temperatures were measured for many of these crystals. The temperature dependence of the relative lattice parameter was measured in selected crystals. This provided lower bounds on the vacancy activation energy.
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Multi-component boron coatings on low carbon steel AISI 1018
… analysis, crystalline size, microstrain and lattice parameters of the multi-component boron coatings. The results have shown that adding transition metals into the B-Fe system caused the formation of solid solution of transition-metal borides. The distortion of crystal lattice parameters …
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Synthesis, X-ray characterization, structural and magnetic studies of a new class of iso-structural BiMO₃ compounds
… is a temperature dependent X-ray study of the lattice parameters of BiFeo₃. The synthesis and subsequent X-ray characterization of BiCo₃, BiAlO₃, BiMnO₃ , BiScO₃, BiCo₁₋ₓFeₓO₃ , and BiAl₁₋ₓFeₓO₃ are reported in the second part. These compounds all crystallize in the body centered cubic (BCC) …
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Investigations into the Form and Design of an Elbow Exoskeleton Using Additive Manufacturing
… showed that given the same volume, changing the lattice parameters can result in different bending stress-strain curves. This thesis also provides many prototypes, test data, and samples for future reference.
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Optimisation of hydroxyapatite (HAp) for orthopaedic application via the chemical precipitation technique
… in order to evaluate the critical process parameters and their effect (main and interaction) on controlling the final HAp powder characteristics, such as, phase composition, purity, crystallinity, crystallite size, lattice parameters, particle size and particle size distribution. These …
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Phase Diagram Determination of (2-Amino-2-Methyl-1, 3-Propanediol) AMPL-TRMP (Trimethylolpropane) Binary System
… Both share the space group P21/n. AMPL shows lattice parameters of: a = 8.62 Å, b = 11.00 Å, c = 6.1(3) Å, â = 93.32(1)0, V = 580.3(5) Å3 at 20 (± 1) 0C, and Dx = 1.211 g. cm-3 for Z = 4; whereas TRMP has: a=0.8427(5), b=0.9580(5), c=0.9185(6) nm, â=98.958(3)° at 298K with Z=4 at room …
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Optical reflectance spectra of chromium (III) in MgO-ss
… ion, chromium, was investigated in a MgO host lattice. The chromium ion incorporated into poly-crystalline MgO by quenching from elevated temperatures allowed investigation of a single crystalline phase, MgO-solid solution (ss). The chromium ion was confirmed to occur in the trivalent state and …
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Dislocation Modeling of Mechanical Properties of Nanolayered Composite Materials
… thickness, and ratio of in-plane stressfree lattice parameters of the two phases are regarded as variables. Also, the degree of coherency of the interfaces and the internal biaxial stress state in each layer prior to loading are predicted as a function of these variables. The results suggest …
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Structural studies using synchrotron X-ray powder diffraction and other techniques
… of Fe$_3$O$_4$ at 60 K has been refined with lattice parameters of a= 5.9412(3) Å, b = 5.9290(3) Å, c = 16.789(1) Å and β = 90.196$^{\circ}$. A variable temperature study of the Fe$_3$O$_4$ lattice parameters between 2-280 K shows this transition is first-order. An EXAFS study between 80-270 K …
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The Development of Alkoxy-Based Sol -Gel Processing for Magnetoresistive Manganite Thin Films
The cubic lattice parameters of the films (i.e., a = ∼ 3.90 A) were in excellent agreement with values published in the literature for bulk, polycrystalline powders. Typical grain sizes started at 10--15 nm, increasing to 20--25 nm by 750°C. For films deposited on Si(100), magnetoresistance …
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Thermal vacancies in hcp helium-4
… between 18.17 and 20.9 cm3/mole. Absolute lattice parameters at low temperatures were measured for many of these crystals. The temperature dependence of the relative lattice parameter was measured in selected crystals. This provided lower bounds on the vacancy activation energy. The …
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Crystal Structures of Helical Columnar pi-Conjugated Systems and Biodegradable Polyester
… arranged within an orthorhombic unit cell with lattice parameters a = 70.2 ± 0.02 Å, b = 41.1 ± 0.02 Å, and c = 45.5 ± 0.02 Å. The space group is determined to be P212121. The internal structure of the columns is approximated by 61 helices. The structure is based on four-molecule repeat units …
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Growth and magnetoelastic behavior of b-axis-oriented dysprosium
… can be prepared on substrates which cause their lattice parameters to differ from bulk values (strain) and which constrain the strictions which may occur (clamping). The present research describes a new MBE growth procedure to grow single crystal thin films and superlattices of rare earths with …
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