Study on the Sintering and Mg Composition Effect on MgB2 Superconducting Bulks and Wires Synthesized by Powder-in-Sealed-Tube Method

2021 ◽  
Vol 1166 ◽  
pp. 1-12
Author(s):  
Md Rauf Ul Karim Khan ◽  
Agung Imaduddin ◽  
Heri Nugraha ◽  
Reiji Hattori ◽  
Andika Widya Pramono
Keyword(s):  
Critical Temperature ◽  
Large Scale ◽  
Stoichiometric Ratio ◽  
Composition Effect ◽  
High Tc ◽  
X Ray ◽  
Superconducting Wires ◽  
Superconducting Wire ◽  
Coherence Lengths ◽  
Sintered Temperature

Numerous research efforts aimed at the MgB2 (Magnesium diboride) as a superconducting material due to its higher critical temperature than Nb-based superconductors such as NbTi, Nb3Sn. Nowadays MgB2 is becoming more popular as the candidate to be applied on medical devices and large-scale applications because of its full coherence lengths, improved critical current density and fields, and simple crystal structure. In this study, we fabricated the 4 mm MgB2 superconducting wires by mixing stoichiometric mole ratio of Mg: B with 1.0:2.0 and 1.1:2.0 through the Powder-In-Sealed-Tube (PIST) method to optimize high critical temperature (TC) than the conventional MgB2 bulk and wire. Furthermore, we decreased the diameter of 4 mm to 1.8 mm wire and analyze the effect of critical temperature. The specimens were sintered at a different temperature to investigate the sintering effect of MgB2 superconducting wire. The resistivity versus temperature relationship, surface morphology, and crystal phase was characterized using Cryogenic system, SEM (Scanning Electron Microscopy), and XRD (X-ray Diffractometer), respectively. We optimized the high Tc,onset for the bulk and 4 mm wire compared to other studies that are 42.1K and 40.3K respectively at 800°C sintered temperature. Finally, the results suggest that the stoichiometric ratio of MgB2 exhibited excellent feasibility to prepare conventional MgB2 superconducting wire.

Energy-dispersive x-ray mapping of grain boundaries in high-Tc superconductors

1993 ◽  
Vol 51 ◽  
pp. 442-443
Author(s):  
J.C. Barry ◽  
G.J. Auchterlonie
Keyword(s):  
Critical Temperature ◽  
Grain Boundaries ◽  
Large Scale ◽  
Current Flow ◽  
Power Transmission ◽  
Electrical Current ◽  
Oxide Superconductors ◽  
High Tc ◽  
Order Of Magnitude ◽  
Better Than

Superconductors are materials which carry electrical current without resistive loss below a certain critical temperature (Tc). There are many potential uses for materials that are superconducting, but until recently the Tc's of known materials were too low to be useful in large-scale applications such as power transmission. However, with the discovery of high Tc oxide superconductors, the feasibility of such projects are now being considered. The problem with the oxide superconductors is not that their critical temperature is too low (the Tc's of the oxides are almost an order of magnitude better than the metal superconductors), but rather that in bulk form their current carrying capacity (Jc) is too low. It is known that the bulk Jc is determined by intergranular conductivity. Low values for Jc may occur because of: (a) a change of stoichiometry at the grain boundaries, or (b) because of misorientation of adjacent grains. High Jc's can be achieved in thin films by texturing the material so that there are few grain boundaries across the direction of current flow but many grain boundaries perpendicular to the current flow.

Investigation of the products of carbothermal reduction of yttrium oxide by the hydrolysis method

1984 ◽  
Vol 49 (4) ◽  
pp. 936-943 ◽  
Author(s):  
Bohumil Hájek ◽  
Pavel Karen ◽  
Vlastimil Brožek
Keyword(s):  
Yttrium Oxide ◽  
Carbothermal Reduction ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Method ◽  
Sample Decomposition ◽  
Products Of Reaction ◽  
Hydrolysis Of ◽  
Lower Carbon

For the investigation of the products of reaction of yttrium oxide with carbon mixed in various proportions, the chemical and X-ray diffraction methods of analysis were combined with the gas chromatographic analysis of the mixture of hydrocarbons and hydrogen formed on the sample decomposition with water. The carboreduction of Y2O3 was examined at relatively low temperatures, convenient for obtaining the reaction intermediates in higher yields. At 1 600 °C and pressures of 10-3 Pa the reduction of a mixture of Y2O3 with carbon in a stoichiometric ratio of 1 : 7 yields YC2 in equilibrium with 20% of Y2OC phase. At lower carbon contents (down to the Y2O3 : C ratio of 1 : 2) tha fraction of the Y2OC phase increases up to approximately 30%. In addition to Y2O3, the reaction mixture contains also Y2C, Y2OC and a phase giving propyne on hydrolysis. The presence of traces of C3 hydrocarbons and small amounts of methane in the product of hydrolysis of the carbide sample prepared by the carbothermal reduction of the oxide can be explained in terms of the occurrence of the Y15C19 phase, probably substituted in part by oxygen, and of the Y2OC phase. The results are compared with those obtained previously for the Sc2O3 + C system.

scholarly journals On the relation between mini-halos and AGN feedback in clusters of galaxies

2020 ◽  
Vol 499 (2) ◽  
pp. 2934-2958
Author(s):  
A Richard-Laferrière ◽  
J Hlavacek-Larrondo ◽  
R S Nemmen ◽  
C L Rhea ◽  
G B Taylor ◽  
...  
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
Vital Role ◽  
Clusters Of Galaxies ◽  
Relativistic Jets ◽  
X Ray ◽  
Core Cluster ◽  
Central Galaxy ◽  
Central Regions ◽  
Radio Power

ABSTRACT A variety of large-scale diffuse radio structures have been identified in many clusters with the advent of new state-of-the-art facilities in radio astronomy. Among these diffuse radio structures, radio mini-halos are found in the central regions of cool core clusters. Their origin is still unknown and they are challenging to discover; less than 30 have been published to date. Based on new VLA observations, we confirmed the mini-halo in the massive strong cool core cluster PKS 0745−191 (z = 0.1028) and discovered one in the massive cool core cluster MACS J1447.4+0827 (z = 0.3755). Furthermore, using a detailed analysis of all known mini-halos, we explore the relation between mini-halos and active galactic nucleus (AGN) feedback processes from the central galaxy. We find evidence of strong, previously unknown correlations between mini-halo radio power and X-ray cavity power, and between mini-halo and the central galaxy radio power related to the relativistic jets when spectrally decomposing the AGN radio emission into a component for past outbursts and one for ongoing accretion. Overall, our study indicates that mini-halos are directly connected to the central AGN in clusters, following previous suppositions. We hypothesize that AGN feedback may be one of the dominant mechanisms giving rise to mini-halos by injecting energy into the intra-cluster medium and reaccelerating an old population of particles, while sloshing motion may drive the overall shape of mini-halos inside cold fronts. AGN feedback may therefore not only play a vital role in offsetting cooling in cool core clusters, but may also play a fundamental role in re-energizing non-thermal particles in clusters.

scholarly journals A Highly Selective Turn-On Fluorescent Probe for the Detection of Zinc

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3825
Author(s):  
Ling-Yi Shen ◽  
Xiao-Li Chen ◽  
Xian-Jiong Yang ◽  
Hong Xu ◽  
Ya-Li Huang ◽  
...  
Keyword(s):  
High Selectivity ◽  
Fluorescence Probe ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Turn On ◽  
Imine Nitrogen ◽  
System A ◽  
Plot Analysis ◽  
L System

A novel turn-on fluorescence probe L has been designed that exhibits high selectivity and sensitivity with a detection limit of 9.53 × 10−8 mol/L for the quantification of Zn2+. 1H-NMR spectroscopy and single crystal X-ray diffraction analysis revealed the unsymmetrical nature of the structure of the Schiff base probe L. An emission titration experiment in the presence of different molar fractions of Zn2+ was used to perform a Job’s plot analysis. The results showed that the stoichiometric ratio of the complex formed by L and Zn2+ was 1:1. Moreover, the molecular structure of the mononuclear Cu complex reveals one ligand L coordinates with one Cu atom in the asymmetric unit. On adding CuCl2 to the ZnCl2/L system, a Cu-Zn complex was formed and a strong quenching behavior was observed, which inferred that the Cu2+ displaced Zn2+ to coordinate with the imine nitrogen atoms and hydroxyl oxygen atoms of probe L.

scholarly journals Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Xianjie Yuan ◽  
Xuanhui Qu ◽  
Haiqing Yin ◽  
Zaiqiang Feng ◽  
Mingqi Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Velocity ◽  
Sintered Density ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
High Velocity Compaction ◽  
Sintered Temperature

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

scholarly journals X-Ray Emission Differences in SNR MSH14-63

1998 ◽  
Vol 11 (1) ◽  
pp. 393-393
Author(s):  
Fangjun Lu ◽  
Mei Wu ◽  
Tipei Li ◽  
Xuejun Sun
Keyword(s):  
Large Scale ◽  
Physical Characteristics ◽  
Energy Bands ◽  
X Ray

In the paper we report the discovery of X-ray emission differences in SNR MSH14-63 based on the ROSAT PSPC observation. The structures of MSH14-63 are different in different energy bands. These images along with the radial brightness distributions in these energy bands show the existence of a region which only emit X-ray photons harder than l.OkeV. Though weak, there actually exist large scale X-ray emissions beyond the bright rim in many parts of the northeast remnant component, which is in conflict with the Sedov phase assumption used in previous research. These new soft X-ray features provide astronomers more information to study its physical characteristics.

scholarly journals The Hot Universe with XRISM and Athena

2018 ◽  
Vol 14 (S342) ◽  
pp. 29-36
Author(s):  
M. Guainazzi ◽  
M. S. Tashiro
Keyword(s):  
Electromagnetic Radiation ◽  
Large Scale ◽  
Cosmological Evolution ◽  
X Ray ◽  
Hot Gas ◽  
Cosmic Vision ◽  
Esa Cosmic Vision ◽  
The Universe

AbstractX-ray spectroscopy is key to address the theme of “The Hot Universe”, the still poorly understood astrophysical processes driving the cosmological evolution of the baryonic hot gas traceable through its electromagnetic radiation. Two future X-ray observatories: the JAXA-led XRISM (due to launch in the early 2020s), and the ESA Cosmic Vision L-class mission Athena (early 2030s) will provide breakthroughs in our understanding of how and when large-scale hot gas structures formed in the Universe, and in tracking their evolution from the formation epoch to the present day.

A Self-Doped Oxygen-Free High-Critical-Temperature (High-Tc) Superconductor: SmFFeAs

2019 ◽  
Vol 58 (22) ◽  
pp. 15401-15409 ◽  
Author(s):  
Dan Lin ◽  
Han-Shu Xu ◽  
Jingjing Luo ◽  
Haoliang Huang ◽  
Yalin Lu ◽  
...  
Keyword(s):  
Critical Temperature ◽  
High Critical Temperature ◽  
High Tc ◽  
High Tc Superconductor

Multinational Enterprises and the Globalization of Medicine: Siemens and the Business of X-ray Equipment in Non-Western Markets, 1900–1939

2014 ◽  
Vol 15 (4) ◽  
pp. 820-848
Author(s):  
Pierre-Yves Donzé
Keyword(s):  
International Organizations ◽  
Multinational Enterprises ◽  
Large Scale ◽  
Multinational Enterprise ◽  
Central Africa ◽  
Great Difficulty ◽  
X Ray ◽  
Hospital Development ◽  
Slight Growth ◽  
The 19Th Century

Whereas the globalization of medicine since the middle of the 19th century has primarily been approached as the sociopolitical and cultural outcome of imperialism, this article argues that Western big business also played a major role through the worldwide export of standardized medical technologies. It focuses on the expansion of Siemens on the X-ray equipment market in non-Western countries during the first half of the twentieth century. This German multinational enterprise experienced slight growth from the mid-1920s onwards but relied mainly on two markets (Argentina and Brazil). It specialized in providing large-scale equipment to a few urban hospitals and engaged during the 1930s in large-scale hospital development together with local authorities and international organizations in various countries (China, Peru, and Central Africa). However, Siemens had great difficulty in expanding its business to include private doctors and inland outlets, where it faced intense competition from other Western X-ray producers. This paper emphasizes that this shortcoming stemmed from a direct application of the European strategy (high-quality, expensive equipment for hospitals) to non-Western markets, where health systems differed.

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