• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.679-687
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• 2005

In this paper we shall give a new definition for a quasi-power module P(M) and discuss some properties for P(M). The quasi-power module P(M) is a direct sum of invertible quasi-submodules C(H)'s of P(M) and then the quasi-submodule C(H) is also a direct sum of strongly cyclic quasi-submodules of C(H). When M is a quasi-perfect right R-module, we shall see that the quasi-power module P(M) is invertible.

• 대한수학회보
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• 제54권2호
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• pp.559-571
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• 2017

We investigate modules M having the injective property relative to nonsingular modules. Such modules are called "$\mathcal{N}$-injective modules". It is shown that M is an $\mathcal{N}$-injective R-module if and only if the annihilator of $Z_2(R_R)$ in M is equal to the annihilator of $Z_2(R_R)$ in E(M). Every $\mathcal{N}$-injective R-module is injective precisely when R is a right nonsingular ring. We prove that the endomorphism ring of an $\mathcal{N}$-injective module has a von Neumann regular factor ring. Every (finitely generated, cyclic, free) R-module is $\mathcal{N}$-injective, if and only if $R^{(\mathbb{N})}$ is $\mathcal{N}$-injective, if and only if R is right t-semisimple. The $\mathcal{N}$-injective property is characterized for right extending rings, semilocal rings and rings of finite reduced rank. Using the $\mathcal{N}$-injective property, we determine the rings whose all nonsingular cyclic modules are injective.

• 생명과학회지
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• 제21권10호
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• pp.1415-1421
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• 2011

이 연구는 L-arginine과 규칙적인 운동이 D-galctose (D-all)투여로 유발된 노화흰쥐의 대동맥에서 발현되는 NF-${\kappa}B$, TNF-a, iNOS, Cav-1, eNOS, Ang II의 변화양상을 관찰하는데 그 목적을 두고 있다. 노화유도 모델 쥐는 D-gal (50 mg/kg)를 숫컷 Strague-Dawley (SD)계 흰쥐의 복강에 1일 1회 총 12주간 투여하여 생산하였으며, 이 실험의 집단은 젊은 대조군(Y-con, n=8), 노화 대조군(A-con, n=8), 노화 운동군(A-Ex, n=8), 노화운동+아르기닌군(A-Ex+A, n=8), 노화 아르기닌군(A-A, n=8)의 5군으로 분류하여 실시하였다. L-arginine은 1일 150 mg/kg씩 총 12주간 경구투여 하였다. 운동방법은 트레이드운동으로 1일 60분씩 20 m/min 속도에서 훈련하였다. 분석결과 1) 유도된 노화군에서 NF-${\kappa}B$, TNF-a, iNOS, Cav-1, 그리고 Ang II 단백질의 발현은 젊은 대조군에 비해 유의하게 증가하였다. 그러나 규칙적인 운동과 L-아르기닌군에서 NF-${\kappa}B$, TNF-a, iNOS, Cav-1, 그리고 Ang II 단백질의 발현은 노화 대조군에 비해 유의하게 감소하였다. 2) 유도된 노화군에서의 eNOS 단백질 발현은 젊은 대조군에 비해 유의하게 감소하였다. 그러나 규칙적인 운동과 L-아르기닌군은 eNOS 단백질의 발현을 더욱 증가시킨 것으로 나타났다. 이상의 결과를 종합하면 12주간 L-아르기닌 투여와 규칙적인 운동 그리고 복합처치는 염증인자와 관련된 단백질인 NF-${\kappa}B$, TNF-a, iNOS 단백질들의 발현을 억제시켜 항염증효과를 보여주었으며, 혈관내피의 기능향상과 관련된 eNOS의 발현을 증가시키는데 긍정적인 역할을 수행할 것으로 기대된다.

• 정보처리학회논문지A
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• 제11A권5호
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• pp.341-346
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• 2004

최근에 병렬처리를 위한 새로운 위상으로 하이퍼-스타 그래프 HS(m, k)가 제안되었다. 하이퍼-스타 그래프는 하이퍼큐브와 스타 그래프의 성질을 가지고 있으면서, 같은 노드수를 갖는 하이퍼큐브 보다 망비용이 우수한 그래프이다 본 논문에서는 하이퍼-스타 그래프 HS(m, k)가 하이퍼큐브의 서브그래프임을 증명한다. 그리고 정규형 그래프인 하이퍼-스타 HS(2n, n)가 제안된 매핑 기법에 의해 노드 대칭임을 보이며, 최소 높이를 갖는 스패닝 트리를 이용한 일-대-다 방송 기법을 제안하고, 방송 수행 시간이 2n-1임을 보인다.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제2권2호
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• pp.111-114
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• 1995

A C$\^$$\infty$/ manifold is a pair (M, C) where a) M is a Hausdorff topological space such that every point $\chi$$\in$M has a neighborhood homeomorphic to an open subset of R$^n$. b) C is a collection of these homeomorphisms whose domains cover M. If ø, $\psi$ $\in$ C then ø o $\psi$$\^$-1/ is C$\^$$\infty$/. c) C is maximal with respect to (b).(omitted)

• 정보처리학회논문지A
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• 제12A권6호
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• pp.499-506
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• 2005

최근에 하이퍼큐브의 망비용을 개선한 하이퍼-스타 연결망 HS(m,k)이 제안되었다. 본 논문에서는 정규연결망 하이퍼-스타 HS(2n,n)의 이분할 에지수가 최대(2n-2,n-1)임을 보이고, 병렬경로 집합을 이용하여 k-광역지름이 dist(u, v)+4이하이고, HS(2n,n)의 고장지름이 D(HS(2n+n))+2 이하임을 보인다. dist(u,v)는 임의의 두 노드 u와 v 사이의 최단 거리를 나타내고, D(HS(2n,n))는 HS(2n,n)의 지름을 나타낸다.

• 한국분말재료학회지
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• 제17권3호
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• pp.209-215
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• 2010

Mesoporous alumina particles were prepared by spray pyrolysis using cetyltrimethyl-ammonium bromide (CTAB) as a structure directing agent and the effect of Al precursor types on the texture properties was studied using $N_2$ adsorption isotherms, small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The surface area and the microstructure of alumina particles were significantly influenced by the Al precursor type. The largest BET surface area was obtained when Al chloride was used, whereas alumina particles prepared from Al acetate had the largest pore volume. According to small-angle X-ray scattering (SAXS) analysis, the alumina powders prepared using nitrate and acetate precursors had a clear single SAXS peak around $2{\theta}=1.0{\sim}1.5^{\circ}$, indicating that regular mesopores with sponge-like structure were produced. On the basis of TEM, SAXS, and $N_2$ isotherm results, the chloride precursor was most profitable to obtain the largest surface area ($265\;m^2/g$), whereas, the nitrate precursor is useful for the preparation of non-hollow mesoporous alumina with regular pore size, maintaining high surface area (${\sim}233\;m^2/g$).

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제28권4호
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• pp.315-328
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• 2021

A characterization of frame operators of finite Gabor frames is presented here. Regularity aspects of Gabor frames in 𝑙²(ℤ_N) are discussed by introducing associated semi-frame operators. Gabor type frames in finite dimensional Hilbert spaces are also introduced and discussed.

• 한국재료학회지
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• 제14권2호
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• pp.133-140
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• 2004

We carried out anodic aluminum oxide (AAO) on a Si and a sapphire substrate. For anodic oxidation of Al two types of specimens prepared were Al(0.5 $\mu\textrm{m}$)!Si and Al(0.5 $\mu\textrm{m}$)/Ti(0.1 $\mu\textrm{m}$)$SiO_2$(0.1 $\mu\textrm{m}$)/GaN(2 $\mu\textrm{m}$)/Sapphire. Surface morphology of Al film was analyzed depending on the deposition methods such as sputtering, thermal evaporation, and electron beam evaporation. Without conventional electron lithography, we obtained ordered nano-pattern of porous alumina by in- situ process. Electropolishing of Al layer was carried out to improve the surface morphology and evaluated. Two step anodizing was adopted for ordered regular array of AAO formation. The applied electric voltage was 40 V and oxalic acid was used as an electrolyte. The reference electrode was graphite. Through the optimization of process parameters such as electrolyte concentration, temperature, and process time, a regular array of AAO was formed on Si and sapphire substrate. In case of Si substrate the diameter of pore and distance between pores was 50 and 100 nm, respectively. In case of sapphire substrate, the diameter of pore and distance between pores was 40 and 80 nm, respectively

• 대한수학회보
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• 제39권2호
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• pp.317-326
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• 2002

In this paper, we establish necessary and sufficient conditions for an exchange ring R to satisfy the n-stable range condition. It is shown that an exchange ring R satisfies the n-stable range condition if and only if for any regular a $\in$ R$^n$, there exists a unimodular u $\in$$^n$ R such that au $\in$ R is a group member, and if and only if whenever a$\simeq$$_n$b with a $\in$ R, b $\in$ M$_n$(R), there exist u $\in$ R$^n$, v $\in$$^n$ R such that a = ubv with uv = 1. As an application, we observe that exchange rings satisfying the n-stable range condition can be characterized by Drazin inverses. These also give nontrivial generalizations of [7, Theorem 10], [13, Theorem 10], [15, Theorem] and [16, Theorem. 2A].