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106. Foreign Tax Credit Regulations: Nexus As The New Credo

Author

Lee, Wooyoung

Subjects
Tax law -- Interpretation and construction, Foreign source income taxation -- Laws, regulations and rules, Government regulation, Tax law, Business, international, Internal Revenue Code
Abstract

INTRODUCTION A U.S. taxpayer that is subject to income tax in both the U.S. and a foreign country can reduce the amount of tax payable to the U.S. by claiming [...]

Published
2022

134. Experimental Determination of SmBa2Cu3O7−δStability Diagram at Low Oxygen Pressures

Author

Lee, Jung-Woo, Song, Joo-Hyun, Park, Insung, Lee, Wooyoung, and Yoo, Sang-Im

Abstract

We experimentally determined the stability diagram of SmBa2Cu3O7−δ(SmBCO) under a low oxygen pressure (PO2) regime of 1–100 mTorr. Sm–Ba–Cu–O amorphous films were used as precursors instead of SmBCO powder in order to avoid oxygen release problem during decomposition of SmBCO. The precursor films were annealed at 780–932 °C at a given PO2region and then quenched. Under a PO2of 20–100 mTorr, the stability line of SmBCO on the log PO2versus 1/T(K–1) diagram is expressed as log (PO2(Torr)) = 19.22–24292/T(K), with a reaction of SmBCO ↔ Sm2BaO4+ liquid (L1). Under the PO2regime of 1–10 mTorr, the stability line of SmBCO is expressed as log (PO2(Torr)) = 17.73–22582/T(K), with a reaction of SmBCO ↔ Sm2BaO4+ Sm2O3+ L2. At the phase boundary between SmBCO ↔ Sm2BaO4+ L1and SmBCO ↔ Sm2BaO4+ Sm2O3+ L2, the reaction of L1↔ L2+ Sm2O3occurs. Based on the above relationship, the stability diagram of SmBCO, including the solid–liquid phase equilibria above its stability line, is accurately constructed, which is crucial for understanding the fundamental mechanism involved in the fabrication of SmBCO-based high-temperature superconducting coated conductors.

Published
2023
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147. Room-temperature ferromagnetic property in MnTe semiconductor thin film grown by molecular beam epitaxy

Author

Kim, Woochul, Park, Il Jin, Kim, Hyung Joon, Lee, Wooyoung, Kim, Sam Jin, and Kim, Chul Sung

Subjects
Epitaxy -- Methods, Semiconductor films -- Properties, Photoelectron spectroscopy -- Methods, X-rays -- Diffraction, X-rays -- Methods, Business, Electronics, Electronics and electrical industries
Abstract

MnTe layers of high crystalline quality were successfully grown on Si(111) and [Al.sub.2][O.sub.3](0001) substrates by molecular beam epitaxy. We have investigated the structure, magnetic and electric transport properties of MnTe layers by using X-ray diffraction (XRD), superconducting quantum interference device (SQUID) magnetometer, physical properties measurement system (PPMS), and X-ray photoelectron spectroscopy (XPS). Characterization of MnTe layers on Si(111) and [Al.sub.2][O.sub.3] (0001) substrates by X-ray diffraction (XRD) revealed a hexagonal structure of polycrystalline growth for MnTe/Si(111) and epitaxial growth for MnTe/[Al.sub.2][O.sub.3](0001), respectively. Investigation of magnetic properties for MnTe layers showed ferromagnetic properties above room temperature unlike antiferromagnetic bulk MnTe materials. The great irreversibility between zero-field-cooling and field-cooling magnetization were observed. Apparent ferromagnetic hysteresis loops are measured at room temperature. In electro-transport measurements, the temperature dependence of resistivity revealed a noticeable semiconducting behaviors and showed a conduction via variable range hopping (VRH) at low temperature. From XPS results, we assume that the origin of ferromagnetism in samples may be due to the breaking of superexchange antiferromagnetic correlations between Mn spin moments arising from Tellurium vacancies. Index Terms--Magnetic semiconductor, molecular beam epitaxy, NiAs-type MnTe, X-ray photoelectron spectroscopy.

Published
2009

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