• Progress in Superconductivity
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• v.9 no.1
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• pp.62-67
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• 2007

The effects of the heat-treatment temperature on the carbon (C) substitution amount, full width at half maximum (FWHM) value, critical temperature ($T_c$), critical current density ($J_c$) have been investigated for 10 wt % malic acid ($C_4H_6O_5$)-doped $MgB_2/Fe$ wires. All the samples were fabricated by the in-situ powder-in-tube (PIT) method and heat-treated within a temperature range of $650^{\circ}C$ to $1000^{\circ}C$. As the heat-treatment temperature increased, it seemed that the lattice distortion was increased by a more active C substitution into the boron sites from the malic acid addition. These increased electron scattering defects seemed to enhance the $J_c-H$ properties in spite of an improvement in the crystallinity, such as a decrease of the FWHM value and an increase of the $T_c$. Compared to the un-doped wire heat-treated at $650^{\circ}C$ for 30 min, the $J_c$ was enhanced by the C doping in a high-field regime. The wire heat-treated at $900^{\circ}C$ resulted in a higher magnetic $J_c$ of approximately $10^4\;A/cm^2$ at 5 K and 8 T.

• Progress in Superconductivity
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• v.10 no.1
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• pp.40-44
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• 2008

A combined process of a mechanical ball milling and liquid glycerin ($C_{3}H_{8}O_3$) treatment of boron (B) powder has been conducted to enhance the superconducting properties of $MgB_2$. The individual aims of the mechanical milling and the glycerin treatment were to reduce the grain size of the $MgB_2$ and to achieve homogeneous carbon (C) incorporation into the $MgB_2$, respectively. Four kinds of B powders of as-received, glycerin treated, 2 h milled, and 2 h milled + glycerin treated were prepared. $MgB_2$ bulks were fabricated by in situ process using the prepared B powders. The mechanical ball milling was effective for a grain refinement, and a lattice disorder was easily achieved by glycerin addition. It was found that the critical current density ($J_c$) values were enhanced in the samples with milled B or glycerin treated B only. In the $MgB_2$ bulk prepared with both milled and glycerin treated B, the $J_c$ was further increased due to a higher grain boundary density and a greater C substitution.

• Journal of the Korean Mathematical Society
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• v.58 no.6
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• pp.1347-1365
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• 2021

For µ = (µ₁, …, µ_t) (µ_j > 0), ξ = (z₁, …, z_t, w) ∈ ℂ^n₁ × … × ℂ^n_t × ℂ^m, define $${\Omega}({\mu},t)=\{{\xi}{\in}\mathbb{B}_{n_1}{\times}{\cdots}{\times}\mathbb{B}_{n_t}{\times}\mathbb{C}^m:{\parallel}w{\parallel}^2 where $\mathbb{B}_{n_j}$ is the unit ball in ℂ^n_j (1 ≤ j ≤ t), C(χ, µ) is a constant only depending on χ = (n₁, …, n_t) and µ = (µ₁, …, µ_t), which is a special type of generalized Cartan-Hartogs domain. We will give some sufficient and necessary conditions for the boundedness of some type of operators on L^p(Ω(µ, t), ω) (the weighted L^p space of Ω(µ, t) with weight ω, 1 < p < ∞). This result generalizes the works from certain classes of generalized complex ellipsoids to the generalized Cartan-Hartogs domain Ω(µ, t).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.303-304
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• 2009

• Food Science and Preservation
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• v.16 no.3
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• pp.454-458
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• 2009

The effect of UV-C irradiation on microbial growth and quality of red pepper powder during storage was examined. Red pepper powder was irradiated with doses of 27, 54, or $108\;kJ/m^2$ and stored at $20^{\circ}C$ for 4 weeks. UV-C treatment of red pepper powder decreased the populations of total aerobic bacteria and Bacillus cereus in proportion to radiation dose. In particular, total aerobic bacteria and B. cereus populations decreased by 1.03 and 0.90 log CFU/g after irradiation at $108\;kJ/m^2$, respectively, compared with control values. UV-C irradiation caused negligible changes in the Hunter color L, a, or b values. Sensory quality results on red pepper powder were not significantly different between treatments. Therefore, UV-C irradiation can be used to inhibit microbial growth in red pepper powder, without impairing quality during storage.

• Proceedings of the KSMRM Conference
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• 1996.10a
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• pp.14-14
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• 1996

• Kyungpook Mathematical Journal
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• v.64 no.1
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• pp.185-196
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• 2024

In this article, we investigate the growth of meromorphic solutions of $${\alpha}(z)(\frac{{\Delta}_c{\eta}}{{\eta}})^2\,+\,(b_2(z){\eta}^2(z)\;+\;b_1(z){\eta}(z)\;+\;b_0(z))\frac{{\Delta}_c{\eta}}{{\eta}} \atop =d_4(z){\eta}^4(z)\;+\;d_3(z){\eta}^3(z)\;+\;d_2(z){\eta}^2(z)\;+\;d_1(z){\eta}(z)\;+\;d_0(z),$$ where a(z), b_i(z) for i = 0, 1, 2 and d_j (z) for j = 0, ..., 4 are given functions, △_cη = η(z + c) - η(z) with c ∈ ℂ\{0}. In particular, when the a(z), the b_i(z) and the d_j(z) are polynomials, and d₄(z) ≡ 0, we shall show that if η(z) is a transcendental entire solution of finite order, and either deg a(z) ≠ deg d₀(z) + 1, or, deg a(z) = deg d₀(z) + 1 and ρ(η) ≠ ½, then ρ(η) ≥ 1.

• Progress in Superconductivity and Cryogenics
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• v.20 no.3
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• pp.11-14
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• 2018

$MgB_2$ superconducting properties have been investigated with the surface-treated boron powders using the chemical solvents. Various solvents were used such as acetone, ethanol, methanol, and water to possibly modify the surface condition of raw boron powders as received. This treatment was done at an argon gas environment inside the glove box to reduce the further contamination during and after chemical treatments. It was found that $T_c$ values were increased to 37.58-37.73 K from the pure sample of 37.50 K when they were treated in inert environment. High- fields $J_c$ at both 5 & 20 K was all increased regardless of any kinds of chemical treatments mentioned above. It is also noted that the $J_c$ at low-fields were increased in the order of solvents: ethanol > acetone > pure $MgB_2$ = methanol > water.

• Electronics and Telecommunications Trends
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• v.17 no.6 s.78
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• pp.193-203
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• 2002

본 고에서는 인터넷 기반에서 디지털 콘텐츠 유료화를 위한 정보거래시스템의 구현을 목표로 디지털 콘텐츠 유료화에 관한 최신의 기술 동향 및 실제적인 시스템 구현을 위한 구성 요소들을 살펴 보고자 한다. 이에 디지털 콘텐츠 유료화를 위해서 반드시 필요되는 디지털 콘텐츠 보안 기술, 과금(빌링)시스템, 전자 결제 방식 및 PG, 디지털 콘텐츠 전송기술, 디지털 콘텐츠 저작권 보호 기술 등에 대한 내용 중심으로 고찰할 것이다. 또한 이를 기반으로 구현하고자 하는 정보거래시스템의 커머스 모델로는 C-to-C 개념으로 인터넷 기반의 정보 생성자와 정보 이용자를 직접 연계하고, 정보 이용에 대한 지불 처리가 가능하도록 하여 기존의 C-to-B 및 B-to-B 기반 전자상거래에서 C-to-C 기반 전자상거래 개념 도입을 통한 정보거래 기반 및 정보 자체에 대한 인터넷 거래 활성화를 유도할 수 있는 기술적 기반 환경을 조성하고, 실제적으로 활용이 가능한 프로토타입 모델을 설계하고자 한다.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.103-103
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• 2009