The Microstructures of the Biomineralized Bivalvia Shells

1989 ◽  
Vol 174 ◽  
Author(s):  
L.J. Huang ◽  
H.D. Li
Keyword(s):  
Electron Spectroscopy ◽  
Structural Features ◽  
X Ray Diffraction ◽  
Vibrational States ◽  
Prismatic Layer ◽  
Preferential Growth ◽  
X Ray ◽  
Growth Orientation ◽  
Laser Raman ◽  
Preferential Growth Orientation

AbstractThe paper presents the detailed study of the structural features of the biomineralized bivalvia shells. The Cristaria plicata(Leach), Anodonta woodianal(Lea) and Lamprotula Leai(Gray) are selected as the prototype in the present study. Scanning electron microscope (SEM), X-ray diffraction, laser Raman spectroscope and electron spectroscopy for chemical analysis (ESCA) are employed to study the structures of the shells. It is found that three different layers of the shells possess distinct morphologies and structures with a clear boundary between every two layers. The prismatic layer can be further divided into two sub–layers. The preferential growth orientation of the biominerahzed phases were different from the natural ones. The Raman spectra present the detailed vibrational states of these biomineralized phases, while ESCA reveals that the chemical environments of the atoms in pearl layer are less varied than those in the other two layers.

Study on Cubic GaN Growth on (001) Rutile TiO2 Substrates by ECR-MBE

2002 ◽  
Vol 743 ◽  
Author(s):  
T. Araki ◽  
H. Mamiya ◽  
K. Kitamura ◽  
Y. Nanishi
Keyword(s):  
Electron Cyclotron Resonance ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
Preferential Growth ◽  
X Ray ◽  
Luminescence Peak ◽  
Cubic Gan ◽  
First Time ◽  
Preferential Growth Orientation ◽  
Resonance Plasma

ABSTRACTGaN layers were grown on a (001) rutile TiO2 substrate by electron cyclotron resonance plasma-excited molecular beam epitaxy. For the first time, c-GaN with a preferential growth orientation was obtained. Based on the results from electron diffraction and X-ray diffraction analysis, we found that c-GaN with the growth direction of [110] was grown on the TiO2 substrate. The formation of c-GaN was also confirmed by cathodoluminescence, in which a luminescence peak was observed at 3.24eV.

Composition, Structure and Electrical Resistivity of ZnO1-x Films Deposited by RF Magnetron Sputtering under Various O2/Ar Gas Ratios

2016 ◽  
Vol 697 ◽  
pp. 723-726 ◽  
Author(s):  
Yang Wang ◽  
Zhi Jian Peng ◽  
Qi Wang ◽  
Xiu Li Fu
Keyword(s):  
Electrical Resistivity ◽  
Magnetron Sputtering ◽  
Rf Magnetron Sputtering ◽  
X Ray Diffraction ◽  
Preferential Growth ◽  
X Ray ◽  
Interstitial Zinc ◽  
Composition Structure ◽  
Ar Gas ◽  
Preferential Growth Orientation

ZnO1-x thin films were deposited by RF magnetron sputtering on conducting silicon wafers at room temperature with ZnOn (n≤1) target under an atmosphere of O2/Ar ratio varying from 0 to 2.0. The correlation between composition, structure and electrical resistivity of the obtained films was investigated. X-ray diffraction analysis revealed that the prepared würtzite ZnO1-x films had c-axis preferential growth orientation. When the O2/Ar ratio was lower than 0.5, the main form of defects in the films was oxygen vacancy; when it was 0.5, the composition of the film approached to the stoichiometric ZnO and had the least number of defects; after that, the main type of defects in the films was interstitial zinc. Thus, with increasing O2/Ar ratio, the electrical resistivity of the films increased first and then decreased.

AIN/GaN and AIGaN/GaN Heterostructures Grown by HVPE on SiC Substrates

1997 ◽  
Vol 482 ◽  
Author(s):  
Yu. V. Melnik ◽  
A. E. Nikolaev ◽  
S. I. Stepanov ◽  
A. S. Zubrilov ◽  
I. P. Nikitina ◽  
...  
Keyword(s):  
Growth Rate ◽  
Electron Beam ◽  
Vapor Phase ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Hydride Vapor Phase Epitaxy ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
X Ray ◽  
Micro Analysis

AbstractGaN, AIN and AIGaN layers were grown by hydride vapor phase epitaxy. 6H-SiC wafers were used as substrates. Properties of AIN/GaN and AIGaN/GaN structures were investigated. AIGaN growth rate was about 1 μm/min. The thickness of the AIGaN layers ranged from 0.5 to 5 μm. The AIN concentration in AIGaN layers was varied from 9 to 67 mol. %. Samples were characterised by electron beam micro analysis, Auger electron spectroscopy, X-ray diffraction and cathodoluminescence.Electrical measurements performed on AIGaN/GaN/SiC samples indicated that undoped AIGaN layers are conducting at least up to 50 mol. % of AIN.

Mechanical and Structural Properties of Superhard TiAlSiN Coatings Deposited by Arc Ion Plating of Cylindrical Cathode

2014 ◽  
Vol 783-786 ◽  
pp. 1426-1431
Author(s):  
Wang Ryeol Kim ◽  
Min Chul Kwon ◽  
Jung Hoon Lee ◽  
Uoo Chang Jung ◽  
Won Sub Chung
Keyword(s):  
Structural Properties ◽  
Nitrogen Pressure ◽  
Structural Features ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ion Plating ◽  
Arc Current ◽  
Cathode Arc ◽  
Cathodic Arc ◽  
Tialsin Coating

TiAlSiN coatings were deposited on WC-Co metal by using a cathodic arc ion deposition method of cylindrical cathode. We used Ti / Al (50 / 50 at.%) arc target and silicon sputter target. The influence of the nitrogen pressure, TiAl cathode arc current, bias voltage, and deposition temperature on the mechanical and the structural properties of the films were investigated. The structural features of the films were investigation in detail using X-ray diffraction. And coatings were characterized by means of FE-SEM, nanoindentation, Scratch tester, Tribology tester, XRD and XPS. The hardness of the film reached 43 GPa at the cathode arc current of 230 A and decreased with a further increase of the arc current. And the adhesion of the film reached 34 N. The results showed that the TiAlSiN coating exhibited an excellent mechanical properties which application for tools and molds.

OMCVD of thin films from metal diketonates and triphenylbismuth

1990 ◽  
Vol 5 (6) ◽  
pp. 1169-1175 ◽  
Author(s):  
A. D. Berry ◽  
R. T. Holm ◽  
M. Fatemi ◽  
D. K. Gaskill
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Atmospheric Pressure ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Strontium Barium ◽  
X Ray ◽  
Scanning Electron

Films containing the metals copper, yttrium, calcium, strontium, barium, and bismuth were grown by organometallic chemical vapor deposition (OMCVD). Depositions were carried out at atmospheric pressure in an oxygen-rich environment using metal beta-diketonates and triphenylbismuth. The films were characterized by Auger electron spectroscopy, Nomarski and scanning electron microscopy, and x-ray diffraction. The results show that films containing yttrium consisted of Y2O3 with a small amount of carbidic carbon, those with copper and bismuth were mixtures of oxides with no detectable carbon, and those with calcium, strontium, and barium contained carbonates. Use of a partially fluorinated barium beta-diketonate gave films of BaF2 with small amounts of BaCO3.

Characterization of hydrofluoric acid treated Y–Ba–Cu–O oxides

1989 ◽  
Vol 4 (6) ◽  
pp. 1320-1325 ◽  
Author(s):  
Q. X. Jia ◽  
W. A. Anderson
Keyword(s):  
Hydrofluoric Acid ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Surface Passivation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zero Resistance ◽  
Reaction With Water ◽  
Scanning Electron

Effects of hydrofluoric acid (HF) treatment on the properties of Y–Ba–Cu–O oxides were investigated. No obvious etching of bulk Y–Ba–Cu–O and no degradation of zero resistance temperature were observed even though the oxides were placed into 49% HF solution for up to 20 h. Surface passivation of Y–Ba–Cu–O due to HF immersion was verified by subsequent immersion of Y–Ba–Cu–O in water. A thin layer of amorphous fluoride formed on the surface of the Y–Ba–Cu–O during HF treatment, which limited further reaction between Y–Ba–Cu–O and HF, and later reaction with water. Thin film Y–Ba–Cu–O was passivated by HF vapors and showed no degradation in Tc-zero after 30 min immersion in water. The properties of the surface layer of Y–Ba–Cu–O oxide after HF treatment are reported from Auger electron spectroscopy, x-ray diffraction, and scanning electron microscopy studies.

Inosose-Flüssigkristalle / Inosose Liquid Crystals

1990 ◽  
Vol 45 (7) ◽  
pp. 1084-1090 ◽  
Author(s):  
Klaus Praefcke ◽  
Bernd Kohne ◽  
Andreas Eckert ◽  
Joachim Hempel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
High Temperature ◽  
Liquid Crystalline ◽  
Structural Features ◽  
Lyotropic Liquid Crystal ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Alkyl Chains

Six S,S-dialkyl acetals 2a-f of inosose (1), tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and differential scanning calorimetry (d.s.c.). The four S,S-acetals 2c-f with sufficiently long alkyl chains are thermotropic liquid crystalline; 2 e and 2 f are even dithermomesomorphic. Each of these four inosose derivatives 2c-f exhibits monotropically a most likely cubic mesophase (MI); in addition 2e and 2f show enantiotropically a hexagonal mesophase (Hx) with a non-covalent, supramolecular H-bridge architecture. Whereas the nature of the optically isotropic mesophase MI needs further clarification the stable high temperature mesophase Hx of 2 e and 2 f has been established by a miscibility test using a sugar S,S-dialkyl acetal also tripodal in structure and with a Hx phase proved by X-ray diffraction, but in contrast to 2 with an acyclic hydrophilic part. Similarities of structural features between the Hx-phases of 2e and 2f as well as of other thermotropic and lyotropic liquid crystal systems are discussed briefly.

Morphological Characterization of Shape-Controlled TiO2 Anatase through XRPD Analysis

2016 ◽  
Vol 230 (9) ◽  
Author(s):  
Mauro Coduri ◽  
Michela Maisano ◽  
Maria Vittoria Dozzi ◽  
Elena Selli
Keyword(s):  
Morphological Characterization ◽  
Morphological Investigation ◽  
X Ray Diffraction ◽  
Preferential Growth ◽  
Rietveld Refinements ◽  
X Ray ◽  
Tio2 Anatase ◽  
Shape Controlled ◽  
Scherrer Equation

AbstractPreferential growth of anatase crystallites along different directions is known to deeply affect their photocatalytic properties, especially with respect to the exposure of the reactive {001} facets. Its extent can be easily quantified through simple geometric calculations, on the basis of crystal sizes extracted for specific directions by means of X-Ray Diffraction data analysis. Nevertheless, the actual results depend on the method employed for such a quantification. Here we report on a comparative morphological investigation, performed by employing the Scherrer equation and the line profile from Rietveld refinements, on shape-controlled anatase photocatalysts produced by employing HF as capping agent. Compared to the Rietveld-based method, the use of the Scherrer equation produces a systematic underestimation of crystallite dimensions, especially concerning the [100] direction, which in turn causes the percentage of exposed {001} crystal facets to be underestimated. Neglecting instrumental-related effects may further reduce the estimate.

scholarly journals Mechanochemical Synthesis of Fluorapatite-Zinc Oxide (FAp-ZnO) Composite Nanopowders

ISRN Ceramics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Bahman Nasiri-Tabrizi ◽  
Abbas Fahami
Keyword(s):  
Zinc Oxide ◽  
Average Crystallite Size ◽  
Structural Features ◽  
Morphological Features ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Remarkable Change ◽  
X Ray ◽  
Process Characterization ◽  
Ft Ir

Fluorapatite-zinc oxide (FAp-ZnO) composite nanopowders were successfully prepared via mechanochemical process. Characterization of the products was carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) analysis, energy dispersive X-ray spectroscopy (EDX), and field-emission scanning electron microscopy (FE-SEM) techniques. Results revealed that in the absence of ZnO which produced by hydrothermal method, the single-phase FAp had high-crystalline structure with appropriate morphological features. Furthermore, after 5 h of milling in the presence of 5 wt.% ZnO, FAp-5 wt.% ZnO, composite nanopowders with no impurity phase was obtained. Structural studies illustrated that the milling up to 5 h was not accompanied by a remarkable change in the structural features. Moreover, the gained composite powders presented an average crystallite size of about 40 nm for FAp. The FE-SEM observations indicated that the experimental outcome had a cluster-like structure which consisted of several small particles. Finally, results propose a new approach to prepare commercial amounts of novel FAp-based composite nanopowders with high quality and suitable structural and morphological features.

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