X-Ray Diffraction Analysis of Simultaneous Changes in Stress and Dislocation Densities in Thin Films

A method has heen developed to determine the dislocation configuration in a polycrystalline specimen from the direction dependence of line broadening. The method is based on an analytical expression for the integral breadth due to microstrain from sets of parallel edge and/or screw dislocations on the specific slip systems. Analysis of the x-ray-diffraction measurements obtained from poly crystalline aluminium layers, deposited onto silicon wafers and subsequently annealed and cooled to room temperature, shows unequal densities and unequal changes of densities of dislocations with the Burgers vector parallel and with the Burgers vector inclined with respect to the surface of the layer. Stress relaxation and dislocation annihilation occur at room temperature. A model was developed to describe the dependency of the decrease of macrostress on the decrease of the dislocation density.

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Dislocation Densities, Slip-System Types and Burgers Vector Populationsinhexagonal and Cubiccrystalsfrom X-Ray Line Profile Analysis

Materials Science Forum ◽

10.4028/www.scientific.net/msf.702-703.479 ◽

2011 ◽

Vol 702-703 ◽

pp. 479-484

Author(s):

Tamás Ungár

Keyword(s):

Line Profile ◽

Profile Analysis ◽

Polycrystalline Materials ◽

Line Profile Analysis ◽

X Ray Diffraction ◽

Burgers Vector ◽

X Ray ◽

Diffraction Line Profile ◽

Vector Population ◽

Dislocation Densities

X-ray diffraction line profile analysis can be carried out on the hkl planes corresponding to the same texture component or the same crystallographic orientation fiber. It is shown that in textured polycrystalline materials or in thin films or multilayers X-ray line profiles measured on planes corresponding either to the main or the minor texture components can provide the Burgers vector population and dislocations densities in the different texture components separately. The experimental technique is outlined for textured specimens and the multiple convolutional whole profile method, i.e. the CMWP line profile analysis procedure, is presented for its capacity to determine the substructure pertaining to different texture components in textured samples.

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Solution Growth and Characterization of Icosahedral Boron Arsenide (B12As2)

MRS Proceedings ◽

10.1557/opl.2011.502 ◽

2011 ◽

Vol 1307 ◽

Author(s):

C.E. Whiteley ◽

Y. Zhang ◽

A. Mayo ◽

J.H. Edgar ◽

Y. Gong ◽

...

Keyword(s):

Room Temperature ◽

Solution Growth ◽

High Quality ◽

Burgers Vector ◽

X Ray ◽

Dislocation Densities ◽

Boron Arsenide ◽

Viable Method ◽

Molten Nickel

ABSTRACTThe crystallographic properties of bulk icosahedral boron arsenide (B12As2) crystals grown by precipitation from molten nickel solutions were characterized. Large crystals (5-8 mm) were produced by dissolving the boron in nickel at 1150°C for 48-72 hours, reacting with arsenic vapor, and slowly cooling to room temperature. The crystals varied in color from black and opaque to clear and transparent. Raman spectroscopy, x-ray topography (XRT), and defect selective etching revealed that the B12As2 single crystals were high quality with low dislocation densities. Furthermore, XRT results suggest that the major face of the plate-like crystals was (111) type, while (100), (010) and (001) type facets were also observed optically. The predominant defect in these crystals was edge character growth dislocations with a <001> Burgers vector, and <-110> line direction. In short, XRT characterization shows that solution growth is a viable method for producing good quality B12As2 crystals.

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Electron Microscopy of Human Gallstones

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065523 ◽

1971 ◽

Vol 29 ◽

pp. 296-297

Author(s):

C. Wolpers ◽

R. Blaschke

Keyword(s):

Electron Microscopy ◽

Room Temperature ◽

Bile Pigment ◽

X Ray Diffraction ◽

Triclinic Crystal System ◽

X Ray ◽

Follow Up Study ◽

Infra Red ◽

Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

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Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100173996 ◽

1990 ◽

Vol 48 (4) ◽

pp. 172-173

Author(s):

Naoki Yamamoto ◽

Makoto Kikuchi ◽

Tooru Atake ◽

Akihiro Hamano ◽

Yasutoshi Saito

Keyword(s):

Phase Transition ◽

Electron Microscope Study ◽

Room Temperature ◽

Hexagonal Lattice ◽

Ferroelectric Materials ◽

Temperature Phase ◽

X Ray Diffraction ◽

X Ray ◽

Periodic Arrays ◽

Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

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Xenon Trioxide Adducts of O-Donor Ligands; [(CH3)2CO]3XeO3, [(CH3)2SO]3(XeO3)2, (C5H5NO)3(XeO3)2, and [(C6H5)3PO]2XeO3

10.26434/chemrxiv.7092263.v1 ◽

2018 ◽

Author(s):

Katherine Marczenko ◽

James Goettel ◽

Gary Schrobilgen

Keyword(s):

Room Temperature ◽

Triphenylphosphine Oxide ◽

Donor Ligands ◽

Mechanical Shock ◽

X Ray Diffraction ◽

X Ray ◽

Oxygen Coordination ◽

Xenon Trioxide ◽

Distorted Octahedra ◽

Coordination Spheres

Oxygen coordination to the Xe(VI) atom of XeO3 was observed in its adducts with triphenylphosphine oxide, dimethylsulfoxide, pyridine-N-oxide, and acetone. The crystalline adducts were characterized by low-temperature, single-crystal X-ray diffraction and Raman spectroscopy. Unlike solid XeO3, which detonates when mechanically or thermally shocked, the solid [(C6H5)3PO]2XeO3, [(CH3)2SO]3(XeO3)2, and (C5H5NO)3(XeO3)2 adducts are insensitive to mechanical shock, but undergo rapid deflagration when ignited by a flame. Both [(C6H5)3PO]2XeO3 and (C5H5NO)3(XeO3)2 are air-stable whereas [(CH3)2SO]3(XeO3)2 slowly decomposes over several days and [(CH3)2CO]3XeO3 undergoes adduct dissociation at room temperature. The xenon coordination sphere of [(C6H5)3PO]2XeO3 is a distorted square pyramid which provides the first example of a five-coordinate XeO3 adduct. The xenon coordination spheres of the remaining adducts are distorted octahedra comprised of three Xe---O secondary contacts that are approximately trans to the primary Xe–O bonds of XeO3. Quantum-chemical calculations were used to assess the Xe---O adduct bonds, which are predominantly electrostatic σ-hole bonds between the nucleophilic oxygen atoms of the bases and the σ-holes of the xenon atoms.

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Effect of trytophan as dopant on potassium acid phthalate single crystals

10.31221/osf.io/cn28k ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Single Crystals ◽

Room Temperature ◽

Visible Region ◽

X Ray Diffraction ◽

X Ray ◽

Slow Evaporation Technique ◽

Absorption Studies ◽

Evaporation Technique ◽

Potassium Acid Phthalate ◽

Acid Phthalate

Optically transparent single crystals of potassium acid phthalate (KAP, 0.5 g) 0.05 g and 0.1 g (1 and 2 mol %) trytophan were grown in aqueous solution by slow evaporation technique at room temperature. Single crystal X- ray diffraction analysis confirmed the changes in the lattice parameters of the doped crystals. The presence of functional groups in the crystal lattice has been determined qualitatively by FTIR analysis. Optical absorption studies revealed that the doped crystals possess very low absorption in the entire visible region. The dielectric constant has been studied as a function of frequency for the doped crystals. The thermal stability was evaluated by TG-DSC analysis.

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Structural and Enhanced Optical Properties of Stabilized γ‒Bi2O3 Nanoparticles: Effect of Oxygen Ion Vacancies

Nanomaterials ◽

10.3390/nano10061023 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1023 ◽

Cited By ~ 2

Author(s):

Ashish Chhaganlal Gandhi ◽

Chia-Liang Cheng ◽

Sheng Yun Wu

Keyword(s):

Room Temperature ◽

Excess Oxygen ◽

Ambient Atmosphere ◽

Photoluminescence Spectra ◽

X Ray Diffraction ◽

X Ray ◽

Band Emission ◽

Oxygen Ion ◽

Integrated Intensity ◽

Effect Of Oxygen

We report the synthesis of room temperature (RT) stabilized γ–Bi2O3 nanoparticles (NPs) at the expense of metallic Bi NPs through annealing in an ambient atmosphere. RT stability of the metastable γ–Bi2O3 NPs is confirmed using synchrotron radiation powder X-ray diffraction and Raman spectroscopy. γ–Bi2O3 NPs exhibited a strong red-band emission peaking at ~701 nm, covering 81% integrated intensity of photoluminescence spectra. Our findings suggest that the RT stabilization and enhanced red-band emission of γ‒Bi2O3 is mediated by excess oxygen ion vacancies generated at the octahedral O(2) sites during the annealing process.

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Mechanical Alloying Behavior in the Nb-Si, Ta-Si, and Nb-Ta-Si Systems

MRS Proceedings ◽

10.1557/proc-133-415 ◽

1988 ◽

Vol 133 ◽

Cited By ~ 3

Author(s):

K. S. Kumar ◽

S. K. Mannan

Keyword(s):

High Temperature ◽

Mechanical Alloying ◽

Mechanical Milling ◽

Room Temperature ◽

Crystalline Compound ◽

X Ray Diffraction ◽

X Ray ◽

Β Phase ◽

Α Phase

ABSTRACTThe mechanical alloying behavior of elemental powders in the Nb-Si, Ta-Si, and Nb-Ta-Si systems was examined via X-ray diffraction. The line compounds NbSi2 and TaSi2 form as crystalline compounds rather than amorphous products, but Nb5Si3 and Ta5Si3, although chemically analogous, respond very differently to mechanical milling. The Ta5Si3 composition goes directly from elemental powders to an amorphous product, whereas Nb5Si3 forms as a crystalline compound. The Nb5Si3 compound consists of both the tetragonal room-temperature α phase (c/a = 1.8) and the tetragonal high-temperature β phase (c/a = 0.5). Substituting increasing amounts of Ta for Nb in Nb5Si3 initially stabilizes the α-Nb5Si3 structure preferentially, and subsequently inhibits the formation of a crystalline compound.

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Synthesis of Magnetic Ferrocene-Containing Polymer with Photothermal Effects for Rapid Degradation of Methylene Blue

Polymers ◽

10.3390/polym13040558 ◽

2021 ◽

Vol 13 (4) ◽

pp. 558

Author(s):

Wenhui Zhu ◽

Caiyun Zhang ◽

Yali Chen ◽

Qiliang Deng

Keyword(s):

Methylene Blue ◽

Photoelectron Spectroscopy ◽

Room Temperature ◽

Degradation Rate ◽

Model Compound ◽

Vibrating Sample Magnetometer ◽

Simulated Sunlight ◽

X Ray Diffraction ◽

X Ray ◽

Ft Ir

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min−1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min−1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.

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Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽

10.3390/chemistry3010013 ◽

2021 ◽

Vol 3 (1) ◽

pp. 149-163

Author(s):

Duncan Micallef ◽

Liana Vella-Zarb ◽

Ulrich Baisch

Keyword(s):

Crystal Structure ◽

Mass Spectrometry ◽

Nuclear Magnetic Resonance ◽

Hydrogen Bonding ◽

Nmr Spectroscopy ◽

Ir Spectroscopy ◽

Room Temperature ◽

Intermolecular Hydrogen Bonding ◽

X Ray Diffraction ◽

X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

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