Some Physical Properties of Suspendable Superconducting 123-Ag Composites

1989 ◽  
Vol 169 ◽  
Author(s):  
C. Y. Huang ◽  
H. H. Tai ◽  
Y. D. Yao ◽  
T. J. Li ◽  
M. K. Wu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Field Dependence ◽  
High Field ◽  
Polarized Light ◽  
Hysteresis Loops ◽  
Residual Magnetization ◽  
Superconducting Transition ◽  
Phase Slippage ◽  
Scanning Electron

AbstractWe have measured the M-H hysteresis loops of n YBa2Cu3Oy: Ag (n = 3,5, and 7), and 3RBa2Cu3Oy:Ag (R = rare earth) as a function of temperature. We have found that the residual magnetization and, hence, pinning, is strong and is independent of n and R, but dependent on the metallurgy. The giant creep rates have been measured and are greater than those of pure 123 samples. Scanning electron microscopy and polarized light microscopy have shown that the presence of silver gives rise to the growth of large grains (~1 mm) in the 123-Ag samples. The field dependence of the critical current density is not strong at high field. We have also measured the resistance in field up to 200 kOe. The resistance remains zero even at 80 K and 200 kOe. The field dependence of the superconducting transition is discussed in terms of phase slippage.

HIGH-FIELD AND MICROSTRUCTURE STUDIES OF SUPERCONDUCTING nYBa2Cu3Oy:AgO COMPOSITES

1989 ◽  
Vol 03 (06) ◽  
pp. 525-535 ◽  
Author(s):  
C.Y. HUANG ◽  
H.H. TAI ◽  
M.K. WU
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Field ◽  
Polarized Light ◽  
Critical Fields ◽  
Strong Pinning ◽  
Current Densities ◽  
Very High ◽  
Scanning Electron

We have measured the resistance of superconducting n YBa 2 Cu 3 O y: AgO (n=2,3,4, and 5) composites above 77 K for magnetic field up to 20 T. The data reveal that the resistance is zero even at 80 K and 20 T. The temperature dependence of the critical field near T c (91.6 K) is very strong, and critical fields at 0 K are thus expected to be very high. Our results of scanning electron microscopy and polarized light microscopy have shown that the presence of silver results in the growth of very large grains (~0.5 mm) with silver dispersed in the grains, giving rise to strong pinning and, hence, large superconducting critical current densities.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Identification of Nd163 phase in melt-textured NdBa2Cu3O7−δ bulk samples

2003 ◽  
Vol 18 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
Marcello Gombos ◽  
Vicente Gomis ◽  
Anna Esther Carrillo ◽  
Antonio Vecchione ◽  
Sandro Pace ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Room Temperature ◽  
Polarized Light ◽  
Energy Dispersive ◽  
X Ray ◽  
Spontaneous Formation ◽  
The Stability ◽  
Scanning Electron

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.

scholarly journals Dielectric Anisotropy in Partially Grain-Oriented Bi2VO5.5Ceramics

1995 ◽  
Vol 18 (3) ◽  
pp. 137-144 ◽  
Author(s):  
K. V. R. Prasad ◽  
K. B. R. Varma
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Orientation ◽  
Hysteresis Loops ◽  
Dielectric Constants ◽  
Dielectric Anisotropy ◽  
Ferroelectric Domains ◽  
Ferroelectric Hysteresis ◽  
Microstructural Studies ◽  
Scanning Electron

Ceramics obtained from quenching melts of prereacted polycrystalline Bi2V5.5exhibit grain orientation (~ 55%). Microstructural studies carried out using scanning electron microscopy (SEM) on subsequently annealed ceramics show ferroelectric domains. These post-annealed ceramics possess dielectric anisotropies of about 1:1.2 at 300 K and 1:4.3 in the vicinity of the Curie temperature (~ 730 K) between the directions parallel and perpendicular to the quenching direction. The dielectric constants of the samples, obtained by quenching the melts, are higher than that of the post-annealed ceramics. Electrically poled and thermally cycled samples of both as-quenched and post-annealed exhibit ferroelectric hysteresis loops at 300 K.

Wood identification of charcoal with 3D-reflected light microscopy

IAWA Journal ◽  
2020 ◽  
Vol 41 (4) ◽  
pp. 478-489 ◽  
Author(s):  
Valentina Zemke ◽  
Volker Haag ◽  
Gerald Koch
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Field Emission ◽  
Polarized Light ◽  
Structural Features ◽  
Light Illumination ◽  
Reflected Light ◽  
Carbonized Wood ◽  
Scanning Electron

Abstract The present study focusses on the application of 3D-reflected light microscopy (3D-RLM) for the wood anatomical identification of charcoal specimens produced from domestic and tropical timbers. This special microscopic technique offers a detailed investigation of anatomical features in charcoal directly compared with the quality of field emission scanning electron microscopy (FESEM). The advantages of using the 3D-RLM technology are that fresh fracture planes of charcoal can be directly observed under the microscope without further preparation or surface treatment. Furthermore, the 3D-technique with integrated polarized light illumination creates high-contrast images of uneven and black charcoal surfaces. Important diagnostic structural features such as septate fibres and intercellular canals can be clearly detected and intervessel pits are directly measured. The comparison of the microscopic analyses reveals that 3D-reflected light microscopy (3D-RLM) provides an effective alternative technique to conventional field emission scanning electron microscopy for the identification of carbonized wood.

scholarly journals Multidisciplinary Approach Applied to the Diagnosis of the Facade of the Arciprestal Church of Santa María de Morella (Castellón, Spain)

Scanning ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Livio Ferrazza ◽  
María T. Pastor Valls ◽  
Gemma M. Contreras Zamorano ◽  
David Juanes Barber ◽  
Roxana Radvan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Multidisciplinary Approach ◽  
Polarized Light ◽  
Second Phase ◽  
Wall Paintings ◽  
Preventive Conservation ◽  
X Ray ◽  
Santa Maria ◽  
Scanning Electron

This paper deals with the development of a multidisciplinary study on the current state of conservation of the facade of the Arciprestal Church of Santa María de Morella (Castellón, Spain), a work of the Gothic period of great historical and artistic value. The aim of this diagnosis was to undertake the preventive conservation actions required and increase the knowledge about the conservation of paintings on stones. During the diagnosis scanning, electron microscopy was demonstrated to be a valuable analytical method for wall paintings on stone. The facade, which since its construction has not undergone major architectural changes, has reached our days as it was configured in its creation, adding the traces of the passage of time and interventions that have suffered polychromies. Because of the conservation situation, it was decided to have an interdisciplinary project for the structural study of the work, an exhaustive study of the materials and their state of conservation. The study of the materials includes the identification of stone supports, mortars, the pictorial technique of the original and added polychromies, and the superficial patinas. On-site studies were carried out by ground penetration radar (GPR) and X-ray fluorescence (XRF). Among the techniques used in laboratory were optical polarized light microscopy (MO-LP), X-ray diffraction (XRD), scanning electron microscopy with microanalysis (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). The study allowed to determine the different pathologies of alteration and degradation of stone substrate and polychromies, chromatic alterations, biological patinas, etc. During this study, it was demonstrated that the diagnosis of wall paintings is a complex issue that needs to be addressed in a multidisciplinary approach, where scanning electron microscopy with microanalysis is the key methodology to get a deeper understanding of subsurface characterization of wall paintings and highlight the weathering processes. In a second phase of previous studies, this technique (SEM) has been used in assessing the viability of consolidation systems and cleaning both the stone and the polychrome.

Morphological Characterization of a Sustained-Release Drug Implant by Scanning Electron Microscopy, Polarized Light Microscopy and Image Analysis

1998 ◽  
Vol 4 (S2) ◽  
pp. 932-933
Author(s):  
J.P. Neilly ◽  
J.S. Deng ◽  
J.L. House ◽  
J.A. Fagerland
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sustained Release ◽  
Light Microscopy ◽  
Polymer Matrix ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
Sustained Drug Release ◽  
Gentamicin Sulfate ◽  
Scanning Electron

Septacin is a sustained-release antibiotic currently under development by the Hospital Products Division of Abbott Laboratories. The product is designed to be used as an anti-infective implant in orthopedic surgical procedures with a sustained drug release for up to six weeks in vivo. It consists of gentamicin sulfate formulated with a bioerodable polyanhydride copolymer. The polymer is biodegradable and has been approved by the FDA for human clinical trials. The final product is obtained by mixing 20% gentamicin sulfate with molten polymer and injection molding it to form cylindrical Septacin beads.The microstructure of drug particles and polymer matrix is critical to the performance of sustained release products, thus scanning electron microscopy (SEM) and polarized light microscopy (PLM) were utilized in this study. SEM has proven useful for evaluating the microstructure of drug formulations3 and was used to examine the drug-polymer matrix structure. Average drug particle size and distribution were determined, and the drug-polymer boundary was evaluated.

MICROSTRUCTURAL STUDIES OF SUPERCONDUCTING 3EuBa2Cu3Oy:AgO AND 3GdBa2Cu3Oy:AgO COMPOSITES

1989 ◽  
Vol 03 (11) ◽  
pp. 877-885
Author(s):  
C.Y. HUANG ◽  
H.H. TAI ◽  
M.K. WU
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Silver Particle ◽  
Polarized Light ◽  
Energy Dispersive ◽  
X Ray ◽  
Grain Formation ◽  
Microstructural Studies ◽  
Scanning Electron

Scanning electron microscopy, energy dispersive X-ray spectroscopy, and polarized light microscopy have shown that the addition of AgO to the E uBa 2 Cu 3 O y and GdBa 2 Cu 3 O y systems results in the growth of very large grains. Distribution of silver particle appears to influence the grain formation and growth in the superconducting composites.

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