scholarly journals Identification by RAMAN Microscopy of magnesian vivianite formed from Fe2+, Mg, Mn2+and P043-’ in a Roman camp near fort Vechten, Utrecht, The Netherlands

2003 ◽  
Vol 82 (2) ◽  
pp. 209-214 ◽  
Author(s):  
J.T. Kloprogge ◽  
D. Visser ◽  
W.N. Martens ◽  
L.V. Duong ◽  
R.L. frost
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
The Netherlands ◽  
Soil Sample ◽  
Raman Microscopy ◽  
Low Intensity ◽  
Bending Modes ◽  
Scanning Electron

AbstractThe presence of a magnesian vivianite (Fe2+)2.5(Mg,Mn,Ca)0.5(PO4)2·8H2O, has been identified in a soil sample from a Roman camp near Fort Vechten, The Netherlands, using a combination of Raman microscopy and scanning electron microscopy. An unsubstituted vivianite and baricite were characterised for comparative reasons. The split phosphate-stretching mode is recognised around 1115, 1062 and 1015 cm−1, while the corresponding bending modes are found around 591, 519, 471 and 422 cm−1. The substitution of Mg and Mn for Fe2+in the crystal structure causes a shift towards higher wavenumbers compared to pure vivianite. As shown by the baričite sample substitution causes a broadening of the bands. The observed broadening however is larger than can be explained by substitution alone. The low intensity of the water bands, especially in the OH-stretching region between 2700 and 3700 cm−1indicates that the magnesian vivianite is partially dehydrated, which explains the much larger broadening than the observed broadening caused by substitution of Mg and Mn in vivianite and baričite.

SYNTHESIS, MORPHOLOGY AND STRUCTURAL PROPERTIES OF (GD,ND)SR2RUCU2O8 SAMPLES

2003 ◽  
Vol 17 (04n06) ◽  
pp. 899-904 ◽  
Author(s):  
A. VECCHIONE ◽  
M. GOMBOS ◽  
C. TEDESCO ◽  
A. IMMIRZI ◽  
L. MARCHESE ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Powder Diffraction ◽  
Solid State Reaction ◽  
X Ray ◽  
Structure And Morphology ◽  
Polycrystalline Powder ◽  
Scanning Electron

NdSr 2 RuCu 2 O x material has been prepared as polycrystalline powder by solid state reaction. The compound has been investigated by synchrotron x-ray powder diffraction and scanning electron microscopy. The experimental results show that the average crystal structure is a disordered cubic perovskite with Nd and Sr cations occupying the same site and the same substitution is found for Cu and Ru atoms. A comparison between the crystal structure and morphology of this compound and the superconducting tetragonal GdSr 2 RuCu 2 O 8 is also discussed.

Crystal Structure of BiFeO3 Synthesized Using the Hydrothermal Processing

2014 ◽  
Vol 602-603 ◽  
pp. 947-950
Author(s):  
Zhen Wang ◽  
Hai Yan Chen ◽  
Lin Qiang Gao ◽  
Xin Zou
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
Hydrothermal Processing ◽  
Optimal Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

BiFeO3 nanoparticles were successfully synthesized by a hydrothermal method by a mineralizer (KNO3). Structural characterization was performed by thermal analysis, powder X-ray diffraction (XRD) and scanning electron microscopy (TEM).The results showed that the products were perovskite structure BiFeO3 powders. Optimal conditions for the synthesis of single-phase BiFeO3 ceramics were obtained.

Leaching Properties of Immobilization of HLW into SrTiO3 Ceramics

2011 ◽  
Vol 332-334 ◽  
pp. 1807-1811 ◽  
Author(s):  
Rui Zhu Zhang ◽  
Yong Wei Gao ◽  
Jian Sheng Wang ◽  
Luke Li ◽  
Wan Shan Su
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Strontium Titanate ◽  
Synthesis Process ◽  
Temperature Synthesis ◽  
Leach Rate ◽  
High Temperature Synthesis ◽  
Technology And Economy ◽  
Scanning Electron

In this work, Strontium Titanate samples were synthsized by self-propagating high-temperature synthesis (SHS). Sr2+ directly took part in the synthesis process. As a result, immobilization limitation issue is basically resolved. The Strontium titanate was characterized by crystal structure, dense properties, leach rate, microstructure and scanning electron microscopy. And the synthesis process is feasible in technology and economy. It can be concluded that the strontium titanate synroc is a perfect material to immobilize HLW.

scholarly journals The influence of mechanical activation on sintering process of BaCO3-SrCO3-TiO2 system

2012 ◽  
Vol 44 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Darko Kosanovic ◽  
N. Obradovic ◽  
J. Zivojinovic ◽  
A. Maricic ◽  
V.P. Pavlovic ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Activation ◽  
Ball Mill ◽  
Sintering Process ◽  
Electrical Measurements ◽  
Air Atmosphere ◽  
Titanate Ceramics ◽  
Scanning Electron

In this article the influence of mechanical activation on sintering process of bariumstrontium-titanate ceramics has been investigated. Both non-activated and mixtures treated in a planetary ball mill for 5, 10, 20, 40, 80 and 120 minutes were sintered at 1100-1400?C for 2 hours in presence of air atmosphere. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100?C was too low to induce final sintering stage for this system. Electrical measurements have been conducted for the densest ceramics sintered at 1400?C for 2 hours.

scholarly journals Fibrinogen variant BβD432A has normal polymerization but does not bind knob “B”

Blood ◽  
2009 ◽  
Vol 113 (18) ◽  
pp. 4425-4430 ◽  
Author(s):  
Sheryl R. Bowley ◽  
Susan T. Lord
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cross Linking ◽  
Dimer Formation ◽  
Fibrin Polymerization ◽  
Per Se ◽  
Clot Structure ◽  
Scanning Electron

AbstractFibrinogen residue Bβ432Asp is part of hole “b” that interacts with knob “B,” whose sequence starts with Gly-His-Arg-Pro-amide (GHRP). Because previous studies showed BβD432A has normal polymerization, we hypothesized that Bβ432Asp is not critical for knob “B” binding and that new knob-hole interactions would compensate for the loss of this Asp residue. To test this hypothesis, we solved the crystal structure of fragment D from BβD432A. Surprisingly, the structure (rfD-BβD432A+GH) showed the peptide GHRP was not bound to hole “b.” We then re-evaluated the polymerization of this variant by examining clot turbidity, clot structure, and the rate of FXIIIa cross-linking. The turbidity and the rate of γ-γ dimer formation for BβD432A were indistinguishable compared with normal fibrinogen. Scanning electron microscopy showed no significant differences between the clots of BβD432A and normal, but the thrombin-derived clots had thicker fibers than clots obtained from batroxobin, suggesting that cleavage of FpB is more important than “B:b” interactions. We conclude that hole “b” and “B:b” knob-hole binding per se have no influence on fibrin polymerization.

Identification of Several New Ferromagnetic and Antiferromagnetic Rare Earth Cuprates

1990 ◽  
Vol 48 (2) ◽  
pp. 498-499
Author(s):  
M. Fendorf ◽  
S.W. Keller ◽  
A.M. Stacy ◽  
R. Gronsky
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Rare Earth ◽  
Magnetic Behavior ◽  
Chemical Form ◽  
The Other ◽  
X Ray ◽  
Scanning Electron ◽  
The Eu

Several new rare earth cuprates having the chemical form RxCuyOz (where R represents the rare earths La, Nd, Sm, Eu, and Gd) have recently been synthesized using a NaOH flux at 400°C. The materials are polycrystalline, and contain varying amounts of R2CuO4 and CuO. During subsequent susceptibility measurements using a SQUID magnetometer, it was found that the Gd material orders antiferromagnetically at approximately 14K, while the other compounds become ferromagnetic between 18K and 28K. Treatment of the powders with 12M HC1 for several minutes dissolves the impurity R2CuO4 and CuO phases, thus facilitating efforts to determine the composition and crystal structure of the new ferromagnetic and antiferromagnetic cuprates. Details of synthesis and magnetic behavior of these materials are to be published elsewhere. In this study, a first attempt is made to characterize the Eu and Gd materials.Energy dispersive x-ray analysis carried out during scanning electron microscopy work indicates that the R:Cu ratio in the Gd material is 1:1.70 (close to 3:5) and that in the Eu material is 1:1.96 (close to 1:2).

scholarly journals Synthesis, Crystal Structure Refinement, and Electrical Conductivity of Pb(8−x)Na2Smx(VO4)6O(x/2)

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Tatiana M. Savankova ◽  
Lev G. Akselrud ◽  
Lyudmyla I. Ardanova ◽  
Alexey V. Ignatov ◽  
Eugeni I. Get’man ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Scanning Electron Microscopy ◽  
Solid Solutions ◽  
Structure Refinement ◽  
Crystal Structure Refinement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Solid solutions of Pb(8−x)Na2Smx(VO4)6O(x/2)were studied using X-ray diffraction analysis including Rietveld refinement and scanning electron microscopy and by measuring their electrical conductivity. Crystal structure of the solid solutions was refined and the solubility region0≤x≤0.2was determined for samarium substitution for lead under the scheme2Pb2++□→2Sm3++O2-. The influence of degree of substitution on the electrical conductivity of solid solutions was established.

The Effect of the Distribution of Ag in High TC Bi- Compound Superconductors

1989 ◽  
Vol 169 ◽  
Author(s):  
Alexis S. Nash ◽  
K. C. Goretta ◽  
Philip Nash ◽  
R. B. Poeppel ◽  
Donglu Shi
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Solid State ◽  
Energy Dispersive Spectrometry ◽  
Temperature Data ◽  
Energy Dispersive ◽  
High Tc ◽  
X Ray ◽  
Scanning Electron

AbstractA series of 4336 Bi‐Sr‐Ca‐Cu oxide samples doped with 1 to 5% metallic Ag was prepared by solid state reaction. The distribution of Ag, the microstructure and the crystal structure of the samples were studied using energy dispersive spectrometry, EDS, scanning electron microscopy, SEM, and x‐ray diffractometry, XRD. Addition of Ag leads to a marked increase in preferred orientation with (001) planes perpendicular to the pressing direction in sintered pellets. The resistivity‐temperature data show an enhanced Tc in Ag‐doped samples under certain conditions. Energy dispersive spectrometry indicates that the dopant mostly segregates to the grain boundaries.

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