• 한국분말재료학회지
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• 제29권6호
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• pp.492-498
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• 2022

N-doped Na₂Ti₆O₁₃@TiO₂ (denoted as N-NTO@TiO₂) composites are successfully synthesized using a simple two-step process: 1) ball-milling of TiO₂ with Na₂CO₃ followed by heat treatment at 900℃; 2) mixing of the prepared Na₂Ti₆O₁₃ with titanium isopropoxide and calcining with urea at 500℃. The prepared composites are characterized using XRD, SEM, TEM, FTIR, and BET. The N-NTO@TiO₂ composites exhibit well-defined crystalline and anatase TiO₂ with exposed {101} facets on the external surface. Moreover, dopant N atoms are uniformly distributed over a relatively large area in the lattice of the composites. Under visible light irradiation, ~51% of the aqueous methylene blue is photodegraded by N-NTO@TiO₂ composites, which is higher than the values shown by other samples because of the coupling effects of the hybridization of NTO and TiO₂, N-doping, and presence of anatase TiO₂ with exposed {101} facets.

• 한국전기전자재료학회논문지
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• 제13권12호
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• pp.989-995
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• 2000

G $e_{1-x}$ S $n_{x}$G $e_{1-y}$S $n_{y}$ is a very promising material for the high-speed device due to the fact that electron and hole mobilities for the strained G $e_{1-x}$ S $n_{x}$G $e_{1-y}$S $n_{y}$ are greatly enhanced. Because G $e_{1-x}$ S $n_{x}$G $e_{1-y}$S $n_{y}$ has a direct band gap for the proper combination of x and y, it can be applied to the optoelectronic device. Therefore, the study of the electrical property for G $e_{1-x}$ S $n_{x}$G $e_{1-y}$S $n_{y}$(001) with a direct energy gap is needed. G $e_{1-x}$ S $n_{x}$ layer can not be grown thickly due to the large difference of lattice constants. This fact prefers the structure of the device where electrons and holes move in the plane direction. The transverse mobilities of electron and hole for G $e_{0.8}$S $n_{0.2}$Ge(001) are 2~3 times larger than those for Ge/Ge/ sub0.8/S $n_{0.2}$(001). Therefore, G $e_{0.8}$S $n_{0.2}$Ge(001) is expected to be better than Ge/G $e_{0.8}$S $n_{0.2}$(001) for the development of the high-speed device.h-speed device.device.h-speed device. device.

• 약학회지
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• 제17권2호
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• pp.111-114
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• 1973

Je-chun clay, Hwa-soon bentonite, and Hwa-soon montmorillonite were treated with treated with organic solvents, i.e., ethylene glycol, ethanol, n-hexane, dioxane, ethylene chlorohydrin and obtained X-ray diffractograms were compared with those of the original samples. Organic solvent was adsorbed on the basal plane surfaces of Je-chun clay, Hwa-soon bentonite, Hwa-soon montmorillonite and, as a result, the axis spacing ws increased, However, organic solvent did not affect the non-expanding lattice of Japanese acid clay and the basal plane remained unchanged.

• Journal of applied mathematics & informatics
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• 제15권1_2호
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• pp.323-331
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• 2004

A new topology in terms of order on fuzzy sets, revealing better the relationship between smooth topology and Chang's fuzzy topology, is presented in the paper. Some basic properties are discussed.

• Progress in Superconductivity
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• 제11권2호
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• pp.135-140
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• 2010

We propose a variational wave function for the ground state of the magnetic heavy fermion (HF) systems, in which both the Kondo and the RKKY interactions are variationally incorporated and the local f-orbital state exists as a linear combination of a full local moment state and a fully compensated state (mixed wave state). We describe the mechanism for the mixed wave ground state based on the large-N treatment of the Kondo lattice Hamiltonian added with RKKY interaction. With the mixed wave ground state we can explain several puzzling experiments in magnetic HF compounds such as a small value of local moment, coexistence of the antiferromagnetic (AFM) and the paramagnetic (PM) phases, local quantum criticality, etc.

• Journal of applied mathematics & informatics
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• 제22권1_2호
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• pp.549-555
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• 2006

Using a t-norm, the notion of T-fuzzy subalgebras of right K(G)-algebras is introduced, and fundamental properties are investigated. The fact that T-fuzzy subalgebras of a right K(G)-algebra form a complete lattice is proved.

• Journal of Magnetics
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• 제15권2호
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• pp.61-63
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• 2010

We used $^1H$ nuclear magnetic resonance (NMR) to study the phase transitions and molecular dynamics in a characteristic ferroelectric liquid crystal with a carbon number n = 7, S-2-methylbutyl 4-n-heptyloxybiphenyl-4'-carboxylate (C7). The results were compared with those of our recent work on S-2-methylbutyl 4-n-octanoyloxybiphenyl-4'-carboxylate (C8), with a carbon number n = 8. While the recrystallization and isotropic phase transitions exhibited a first-order nature in the $^1H$ NMR spin-lattice and spin-spin relaxation measurements, a second-order nature was shown at the Sm-A - Sm-$C^*$ liquid crystalline phase transition. A soft-mode anomaly arising from the tilt angle amplitude fluctuation of the director, of which only a hint had been noticed in the C8 system, was manifested in the C7 system at this transition.

• 대한수학회보
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• 제39권1호
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• pp.63-69
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• 2002

Given vectors x and y in a Hilbert space, an intepolating operator is a bounded operator T such that Tx=y. an interpolating operator for n vectors satisfies the equation Tx$_{i}$=y, for i=1, 2,…, n. In this article, we obtained the fellowing : Let x = (x$_{i}$) and y = (y$_{i}$) be two vectors in H such that x$_{i}$$\neq$0 for all i = 1, 2,…. Then the following statements are equivalent. (1) There exists an operator A in AlgＬ such that Ax = y, A is a trace-class operator and every E in Ｌ reduces A. (2) (equation omitted).mitted).

• 한국세라믹학회지
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• 제28권6호
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• pp.437-442
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• 1991

Temperature and atmosphere dependence of electrical conduction of the metal Cu, Ag, Au films, vaccum evaporated on glass, was investigated. The structural changes of the metal films were examined by SEM and high temperature XRD. The electrical resistance slightly increased with initial temperature increase up to the inflection point and decreased to minimum value, after this rapidly increased with further temperature increased below minimum. These phenomena were caused by the thermally induced film failure as a result of the mass transport. The temperature for the film failure increased in the order of O2, Air, Vacuum, N2, Ar in Cu, Ag films and Air, Vacuum, N2, Ar in Au film. The increase of resistance at the lower temperature range was attributed to the lattice distortion by disordered crystal structure, while the decreasing resistance was attributed to the removal of structural defects and film densification.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.690-693
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• 2003

An Si substrate (100) was oxidized at $400^{\circ}C$ in inductively coupled oxygen plasma. Interstitial oxygen was found in the Si substrate at the initial stage of oxidation by IR measurements. An x-ray rocking curve of Si substrates showed a lower peak intensity due to lattice distortion by the interstitial oxygen. The refractive index of thin oxides, below which interstitial oxygen existed in the Si substrate, was smaller than the refractive index of thick oxides, below which no interstitial oxygen existed. The interstitial oxygen was found by plasma oxidation using $O_{2}$ gas and $N_{2}O$ gas. The inductively coupled plasma oxidation using $N_{2}O$ gas was performed by atomic oxygen, not by molecular oxygen, indicating that atomic oxygen in plasma is responsible for the incorporation of interstitial oxygen.