Einfluß der Dotierung von BaPb0,75Bi0,25O3 mit K, Rb und Cs auf dessen supraleitende Eigenschaften

1991 ◽  
Vol 46 (1) ◽  
pp. 60-62 ◽  
Author(s):  
M. Jansen ◽  
J. Bredthauer
Keyword(s):  
Solid Solutions ◽  
Squid Magnetometer ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
X Ray ◽  
3 Dimensional ◽  
Dimensional Array ◽  
Nominal Stoichiometry

xIn the series with nominal stoichiometry Ba1-xAxPb0,75Bi0,25O3 (A = K, Rb with = 0.1, 0.2, 0.3, and A = Cs with x = 0.1) solid solutions were prepared. The composition of the samples obtained was verified by X -ray techniques. All compounds crystallize tetragonally with a 3-dimensional array of Pb(Bi) - O6 octahedra and Pb(Bi) -O -Pb(Bi) bonding angles of 180° (c-axis) and 165° (xK = 0.3) 168° (xRb = 0.3 and xCs = 0.1) within the a/b plane. Superconducting transition temperatures o f Ba1-xAxPb0,75Bi0,25O3 with Te = 12 (“onset”) were determined using a SQUID magnetometer.

Structure and properties of solid solutions in the Mg-Al-B system

Open Physics ◽  
2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Ludmila Sevastyanova ◽  
Olga Gulish ◽  
Vladimir Stupnikov ◽  
Vladimir Genchel ◽  
Oleg Kravchenko ◽  
...  
Keyword(s):  
Solid Solutions ◽  
Unit Cell ◽  
Superconducting Transition ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Resistivity Measurements ◽  
Ceramic Synthesis

AbstractCompounds with the general formula Mg1−x AlxB2 were obtained by two-step ceramic synthesis. All compounds were characterized by X-ray diffraction, NMR spectroscopy, and by four point probe resistivity measurements in various magnetic fields method. The diborides unit cell parameters were determined as a function of the Al mole fraction. With the vaues of x up to 0.40 (where x is the composition of the stock prepared for sintering), the unit cell parameters of Mg1−x AlxB2 are similar to those of pure MgB2 and the superconducting transition temperature was lowered. For stock compositions of 0:25 ≤ x ≤ 0:60, the products contain a superstructure, also superconducting phase, which becomes the only product at x = 0:50, and at x > 0:60 this phase is replaced by AlB2-based solid solutions.

Aluminum Incorporation in Cuprate Perovskites

1987 ◽  
Vol 99 ◽  
Author(s):  
T. Siegrist ◽  
L. F. Schneemeyer ◽  
J. V. Waszczak ◽  
S. A. Sunshine ◽  
N. P. Singh ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Diamagnetic Susceptibility ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray

ABSTRACTAluminum incorporation in cuprate perovskite single crystals has been studied by single crystal x-ray diffraction. We find that Al substitutes for copper in the Cu-O chains only. Superconducting transition temperatures, Tc, determined by dc diamagnetic susceptibility measurements, change only slightly, to «80K for ×=0.l, then drop sharply with higher aluminum concentrations.

STRUCTURAL INSTABILITY IN A Bi–Sr–Ca–Cu–O SYSTEM

1989 ◽  
Vol 03 (16) ◽  
pp. 1241-1246 ◽  
Author(s):  
XIAOHUA CHEN ◽  
HUIMIN SHEN ◽  
YENING WANG
Keyword(s):  
Phase Transition ◽  
Elastic Modulus ◽  
Internal Friction ◽  
Room Temperature ◽  
Structural Instability ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elastic Softening

Measurements of internal friction and elastic modulus on Bi–Sr–Ca–Cu–O system reveal that a certain kind of phase transition take place a few tens degrees higher than T c . X-ray diffraction measurements show that the symmetry remains unchanged from room temperature to 77 K but the lattice parameters jump at the transition temperatures. Ferroelastic loop were measured around the temperatures mentioned above, which indicates the existence of movable boundaries and elastic softening. It is considered that the instability favor the superconducting transition followed.

HIGH TEMPERATURE SUPERCONDUCTIVITY IN Y-Ba-Cu-Nb-O SYSTEM

1988 ◽  
Vol 02 (03n04) ◽  
pp. 435-441 ◽  
Author(s):  
N. G. SURESHA ◽  
S. HIGO ◽  
Y. HAKURAKU ◽  
T. OTAWA ◽  
Y. HONJO ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
High Temperature ◽  
Powder Diffraction ◽  
High Temperature Superconductivity ◽  
Gradual Change ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
Oxide Superconductor ◽  
X Ray ◽  
Diffraction Patterns

Results of the resistivity and magnetic susceptibility measurements for an oxide superconductor with nominal compositions of Y 1 Ba 2( Cu 1−x Nb x)3 O 6+δ and Y 0.4 Ba 0.6 ( Cu 1−x Nb x) O 2+δ where x = 0.1, 0.15, 0.2, are reported. Superconducting transition temperatures, T c onset (T co ) and T c final (T cf ) are above 90 K and 80 K respectively. We have observed a gradual change in the X-ray powder diffraction patterns of the samples with the change in x.

The 3-Dimensional Molecular Structure of the Actin Filament Revisited

1985 ◽  
Vol 43 ◽  
pp. 480-481
Author(s):  
U. Aebi ◽  
R. Millonig ◽  
H. Salvo
Keyword(s):  
Actin Filament ◽  
Supramolecular Assembly ◽  
Specimen Preparation ◽  
X Ray Diffraction ◽  
Single Filament ◽  
X Ray ◽  
3 Dimensional ◽  
Filament Diameter ◽  
Preparation Conditions ◽  
Apparent Diameter

To date, most 3-D reconstructions of undecorated actin filaments have been obtained from actin filament paracrystal data (for refs, see 1,2). However, due to the fact that (a) the paracrystals may be several filament layers thick, and (b) adjacent filaments may sustantially interdigitate, these reconstructions may be subject to significant artifacts. None of these reconstructions has permitted unambiguous tracing or orientation of the actin subunits within the filament. Furthermore, measured values for the maximal filament diameter both determined by EM and by X-ray diffraction analysis, vary between 6 and 10 nm. Obviously, the apparent diameter of the actin filament revealed in the EM will critically depend on specimen preparation, since it is a rather flexible supramolecular assembly which can easily be bent or distorted. To resolve some of these ambiguities, we have explored specimen preparation conditions which may preserve single filaments sufficiently straight and helically ordered to be suitable for single filament 3-D reconstructions, possibly revealing molecular detail.

Prediction of phonon-mediated superconductivity in two-dimensional Mo2B2

2019 ◽  
Vol 7 (9) ◽  
pp. 2589-2595 ◽  
Author(s):  
Luo Yan ◽  
Tao Bo ◽  
Peng-Fei Liu ◽  
Bao-Tian Wang ◽  
Yong-Guang Xiao ◽  
...  
Keyword(s):  
Two Dimensional ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
Molybdenum Boride

We predict two new molybdenum boride monolayers as phonon-mediated superconductors with superconducting transition temperatures of 3.9 and 0.2 K.

scholarly journals Visualization Ability of Phase-Contrast Synchrotron-Based X-Ray Imaging Using an X-Ray Interferometer in Soft Tissue Tumors

2021 ◽  
Vol 20 ◽  
pp. 153303382110101
Author(s):  
Thet-Thet Lwin ◽  
Akio Yoneyama ◽  
Hiroko Maruyama ◽  
Tohoru Takeda
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Spatial Resolution ◽  
Phase Contrast ◽  
Soft Tissue Tumors ◽  
X Ray ◽  
3 Dimensional ◽  
Computed Tomography Images ◽  
X Ray Imaging ◽  
X Ray Computed

Phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer provides high sensitivity and high spatial resolution, and it has the ability to depict the fine morphological structures of biological soft tissues, including tumors. In this study, we quantitatively compared phase-contrast synchrotron-based X-ray computed tomography images and images of histopathological hematoxylin-eosin-stained sections of spontaneously occurring rat testicular tumors that contained different types of cells. The absolute densities measured on the phase-contrast synchrotron-based X-ray computed tomography images correlated well with the densities of the nuclear chromatin in the histological images, thereby demonstrating the ability of phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer to reliably identify the characteristics of cancer cells within solid soft tissue tumors. In addition, 3-dimensional synchrotron-based phase-contrast X-ray computed tomography enables screening for different structures within tumors, such as solid, cystic, and fibrous tissues, and blood clots, from any direction and with a spatial resolution down to 26 μm. Thus, phase-contrast synchrotron-based X-ray imaging using an X-ray interferometer shows potential for being useful in preclinical cancer research by providing the ability to depict the characteristics of tumor cells and by offering 3-dimensional information capabilities.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

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