40 Result(s)
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Article
Open AccessEffect of Ultra-sonicated Y2BaCuO5 on Top-Seeded Melt Growth YBa2Cu3Oy Bulk Superconductor
In this work, we tried to improve the superconducting performance of bulk YBa2Cu3Oy (Y123) superconductors via Y2Ba1Cu1O5 (Y211) secondary phase refinement. A novel method of ultra-sonication was used to refine t...
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Article
Transmission EBSD (t-EBSD) as Tool to Investigate Nanostructures in Superconductors
The transmission electron backscatter diffraction (t-EBSD) technique has proven to be an indispensable tool for the analysis of microstructures of superconducting samples, both high-Tc samples (YBa2Cu3Oy, Bi2Sr2C...
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Article
Single-Grain Bulk YBa2Cu3Oy Superconductor Grown in Shorter Duration by IG Process
The top-seeded infiltration growth (IG) process is considered to be an attractive, well-established route compared to melt growth (MG) process due to its successful ability to resolve observed problems in MG p...
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Article
Progress in Critical Current Density (Jc) in Sintered MgB2 Bulks
The present paper focuses on methods of further improving the flux pinning and critical current density of disk-shaped MgB2 bulk superconductors by adding excess Mg metal in combination with an optimum silver con...
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Article
Optimization of the Dy Content in Single Crystalline GdBCO Bulk Superconductors Fabricated in Air Via Top-Seeded Infiltration Growth Process
Single-crystalline bulk GdBa2Cu3O7−δ (GdBCO) superconductors were fabricated with top-seeded infiltration-growth technique (TSIG) in air by adding the different amounts of Dy2BaCuO5 (Dy-211) part...
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Article
Effect of Ag Addition on Microstructure and Raman Vibrational Modes of Bulk FeSe
We have synthesized polycrystalline bulk FeSe materials with various Ag concentrations through double-sintering solid-state reaction. All the samples exhibited similar onset critical temperature of around 8 K....
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Article
Interplay of YBCO and Embedded 211 Particles in Melt-Textured YBCO Superconductors
Local orientations of superconducting YBa2Cu3O x (123) and embedded Y2BaCuO5 (211) particles within bulk, melt-textured 123 samples are studied on a local scale by means of elec...
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Article
Nanosized Pinning Sites in HTSC Compounds
Due to the small coherence lengths of the high-T c compounds, effective pinning sites are defects or particles of nanometer size according to ξ3. Integral magnetic measurements of the magnetization as a function ...
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Article
Anisotropic Electrical Transport in MgB2 Single Crystals
We report on study of transport properties of MgB2 single crystals. The normal state resistivity has been found to be anisotropic with resistivity ratio ρ c /ρ
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Article
Low Temperature Scanning Tunneling Spectroscopy Studies of High J c NdBa2Cu3O7 − δ Single Crystals
We report low temperature scanning tunneling spectroscopy (STS) studies on NdBa2Cu3O7 − δ (Nd123) single crystals. Two characteristic spectra with a nearly ohmic background spectrum and a V-shaped background are ...
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Article
Magnetic and Electrical Properties of Single-Crystal La1.99Sr0.01Cu1 − y Ni y O4
We report the out-of-plane and in-plane magnetic susceptibility and resistivity of Ni-doped La1.99Sr0.01CuO4 single crystals grown by Traveling-Solvent Floating-Zone technique. Our data shows that in lightly Sr-d...
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Article
SQUID and Magneto-Optic Investigations of Flux Turbulence in the Critical State
Instabilities of the critical state (“turbulence”) are observed in various high-T c single crystals by means of magneto-optic (MO) imaging. Using the same samples as in the MO investigations, we observe character...
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Chapter
Visualization of DC Gas Flows in a Double-Inlet Pulse Tube Refrigerator with a Second Orifice Valve
We have observed the secondary flow induced in a double-inlet pulse tube refrigerator by using a smoke-wire flow visualization method and investigated the effects of the opening of the bypass valve on the flow...
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Chapter
Visualization Study of the Local Flow Field in an Orifice and Double-Inlet Pulse Tube Refrigerator
The local flow behavior inside an orifice and a double-inlet pulse tube refrigerator has been observed during a cycle by using a smoke-wire and a tuff flow visualization technique. To clarify the difference be...
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Article
Magnetic Properties of Superconducting and Nonsuperconducting (Nd0.33Eu0.33Gd0.33)Ba2Cu3Oy
The temperature dependence of the DC susceptibility χ(T) is measured between 1.7 and 350 K on superconducting and nonsuperconducting bulk melt-processed (Nd0.33Eu0.33Gd0.33)Ba2Cu3Oy by means of SQUID magnetometry...
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Chapter
Visualization Study of Heat Transport Mechanism in Supercritical Nitrogen
Heat transport mechanisms in supercritical nitrogen are examined by using a laser holographic interferometer. The experimental apparatus for the visualization study is designed to observe the process of therma...
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Chapter
Study of Shock Waves and Phase Transition in He II by Using a Superfluid Shock Tube Facility
In the experimental study, we focus on the thermo-fluid dynamics of shock waves and the lambda phase transition, He II to He I, induced by shock compression utilizing the newly developed superfluid shock tube ...
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Chapter
Development of Superconductive Hot-Wire Anemometer for Use Around 2 K
A superconductive hot-wire anemometer has been developed to be used in the measurement of low speed helium vapor flow around 2 K for the study of evaporation from a Hell free surface. The hot-wire element is m...
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Chapter
Investigation of Noisy Film Boiling Under Various Thermal Conditions in He II
In the present study, some experimental results on noisy film boiling in He II are presented. Based on the study of the pressure oscillation of noisy film boiling under various thermal conditions, e.g. differe...
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Chapter
Experimental Study on the Transition of He II Boiling Modes with the Hydrostatic Pressure Around the Lambda Temperature
The transition of film boiling modes in He II with the change of the hydrostatic pressure is studied experimentally. Special attention is paid to the pressure dependence of boiling modes around the λ temperatu...
