• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권7호
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• pp.331-338
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• 2002

An inverter-fed induction is driven by a harmonic voltage source so that it is necessary to be analysed by time-stepping F.E.M. But it takes so long time that disadvantageous to design. This paper presents a simple analysis method for inverter-fed induction motor using FEM and harmonic equivalent circuit. First, the rotor bar resistance and the leakage reactance are determinated by FEA for 1 slot region in rotor to consider the skin effect and the saturation. Secondly, the characteristic of the motor is analyzed by the harmonic equivalent circuits consisting of the obtained parameters from the FEA. This method is carried out to analyze an induction motor driven by the sinusoidal voltage and the inverter. The results are verified by comparing with those of the time-step F.E.A and the experiment.

• Korean Journal of Mathematics
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• 제21권4호
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• pp.463-471
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• 2013

Let R be a ring with identity 1, $I(R){\neq}\{0\}$ be the set of all nonunit idempotents in R, and M(R) be the set of all primitive idempotents and 0 of R. We say that I(R) is additive if for all e, $f{\in}I(R)$ ($e{\neq}f$), $e+f{\in}I(R)$. In this paper, the following are shown: (1) I(R) is a finite additive set if and only if $M(R){\backslash}\{0\}$ is a complete set of primitive central idempotents, char(R) = 2 and every nonzero idempotent of R can be expressed as a sum of orthogonal primitive idempotents of R; (2) for a regular ring R such that I(R) is a finite additive set, if the multiplicative group of all units of R is abelian (resp. cyclic), then R is a commutative ring (resp. R is a finite direct product of finite field).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.128-131
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• 1997

기본 조성식 M $n_{1-x}$/F $e_{2+x}$/ $O_4$(이하 Mg계), M $n_{1-x}$/F $e_{2+x}$/ $O_4$(이하 Mg계)의 식에서 x를 0.0,0.025,0.1,0.2로 변화시키고, 하소온도 80$0^{\circ}C$, 소결은도를 l10$0^{\circ}C$~12$50^{\circ}C$로 $50^{\circ}C$간격으로 변화 시켰을 때와 Mn계와 Mg계를 1:1로 흔합하였을 때, F $e_2$ $O_3$의 과잉 양이 증가할수록 비저항은 감소하였고, 저항온도계수 $\alpha$는 밀도와 비례하는 관계를 나타내었으며, B정수는 4600(K)에서 10500(K)의 범위를 나타내었다. 본 조성의 실험으로써 Mn-Ni-Co계 서미스터의 대체가 가능함을 확인할 수 있었다.있었다.

• 대한수학회보
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• 제52권5호
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• pp.1559-1568
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• 2015

The relative class number $H_d(f)$ of a real quadratic field $K=\mathbb{Q}(\sqrt{m})$ of discriminant d is the ratio of class numbers of $O_f$ and $O_K$, where $O_K$ denotes the ring of integers of K and $O_f$ is the order of conductor f given by $\mathbb{Z}+fO_K$. In a recent paper of A. Furness and E. A. Parker the relative class number of $\mathbb{Q}(\sqrt{m})$ has been investigated using continued fraction in the special case when $(\sqrt{m})$ has a diagonal form. Here, we extend their result and show that there exists a conductor f of relative class number 1 when the continued fraction of $(\sqrt{m})$ is non-diagonal of period 4 or 5. We also show that there exist infinitely many real quadratic fields with any power of 2 as relative class number if there are infinitely many Mersenne primes.

• 한방재활의학과학회지
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• 제18권2호
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• pp.1-15
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• 2008

Objectives : The aim of this study was to know the immunity response of Haedongpibokhap-bang($H{\check{a}}it{\acute{o}}ngp{\acute{i}}f{\grave{u}}h{\acute{e}}-f{\bar{a}}ng$) to rheumatoid arthritis in collagen-induced arthritis(CIA) mice. Methods : For this purpose, Haedongpibokhap-bang($H{\check{a}}it{\acute{o}}ngp{\acute{i}}f{\grave{u}}h{\acute{e}}-f{\bar{a}}ng$) was orally administerd to mice with arthritis induced by collagen II and then value of immunocyte in spleen, draining lymph node and paw joint and cytokine(IL-6, $TNF-{\alpha}$), rheumatoid factor (IgG and IgM) in serum were measured. Results : 1. The arthritis index was significantly decreased. 2. In total cell counts of spleen, DLN and paw joint, the cells in spleen decreased while there was a significant increase in DLN and significant decrease in paw joint. 3. In lymph nodes, CD3+, CD3+/CD69+, CD4+, CD8+ cells increased significantly. 4. In joints, CD3+ and CD11+b/Gr-1+ cells decreased significantly. 5. Serum IL-6 and $TNF-{\alpha}$ were decreased significantly. 6. Production of serum IgG and IgM decreased significantly. Conclusions : The results present that Haedongpibokhap-bang($H{\check{a}}it{\acute{o}}ngp{\acute{i}}f{\grave{u}}h{\acute{e}}-f{\bar{a}}ng$) controls abnormal activity of immune system, inhibitig collagen-induced arthritis(CIA).

• 한국산림과학회지
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• 제73권1호
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• pp.9-13
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• 1986

Juniperus rigida의 경남(慶南)과 충북(忠北)의 두 산지종(産地種)에 대하여 핵형분석(核型分析)을 하였다. 염색체수(梁色體數)는 두 산지종(産地種) 공(共)히 2n=22이다. 두 산지종(産地種)에 있어 가장 공통적(共通的)인 특징(特徵)을 나타낸 염색체(染色體)는 두완(短腕)에 secondary constriction을 지닌 No.7 이고, 가장 특이적(特異的) 특징(特徵)을 한 염색체(染色體)는 secondary constriction을 지닌 경남산(慶南産)의 No.9와 충북산(忠北産)의 No.5 염색체(染色體)이다. 핵형식(核型式)은 다음과 같다. 경남산지종(慶南山地種) $$K(2n)=22=2A^m+2B^m+2C^m+2D^{sm}+2E^{st}+2F^m+2^{sc}G^m+2H^m+2^{sc}I^t+2J^{st}+2K^m$$ 충북산지종(忠北山地種) $$K(2n)=22=2A^m+2B^m+2C^m+2D^{st}+2^{sc}E^{sm}+2F^m+2^{sc}G^m+2H^m+2I^m+2J^{st}+2K^{sm}$$.

• Corrosion Science and Technology
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• 제16권1호
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• pp.48-48
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• 2017

• Journal of Photoscience
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• 제4권1호
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• pp.1-5
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• 1997

A hitherto unknown diphenylbutadiene analog viz. 1-(p-N,N-dimethylaminophenyl)-4-phenyl-2-methyl-1E,3E-butadiene (10) has been prepared and its absorption, excitation, and fluorescent emission properties in different media including various organic solvents and aqueous bovine serum albumin (BSA) have been studied. For comparision, these properties have also been investigated for the parent diphenylbutadiene (2). Diene 10 exhibits solvent polarity/polarizability-sensitive fluorescence properties ($\lambda$$_{max}$, $\Phi$$_f$, $\tau$$_f$, K$_f$, f). It also binds to the hydrophobic domains of aqueous bovine serum albumin (BSA) with a binding constant of 3.89 x 10$^4$ M$^{-1}$. The relative fluorescence quantum yield of 10 increases, while, the fluorescence lifetime decreases with increasing concentration of-BSA. The results highlight the polar character of the singlet excited state of diphenylpolyenes and the utility of 10 as fluorescence probe for studying microenvironments of organized assemblies and biological supramolecular structures.

• 한국자기학회지
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• 제10권2호
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• pp.49-52
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• 2000

비정질 F $e_{81}$ $B_{13.5}$S $i_{3.5}$ $C_2$리본에서 중성자 조사 후 X-선 회절, 상온에서의 자기이력곡선, 자화의 온도의존성 그리고 복소 투자율 측정하고, 결함에 의한 자기 특성과 관련하여 분석하였다. 중성자 조사량은 열 중성자( $n_{th}$)와 고속 중성자( $n_{f}$)가 각각 6.95$\times$$10^{18}$ $n_{th}$$cm^{-2}$ 과 4.56$\times$$10^{16}$ $n_{f}$$cm^{-2}$ 이었다. 중성자 조사된 시료의 X-선 회절상의 변화는 보이지 않았다. 중성자 조사 후, 복소 투자율의 자기이완특성에서 자벽운동에 의한 부분은 감소하였고, 자화회전에 의한 자기이완 주파수는 좀더 높은 주파수 영역으로 이동하였는데 , 이는 pinning력이 증가된 것을 반영한다. 자기이력곡선에서는 중성자 조사 후의 시료의 softness는 좋아지는 한편 포화자화값은 감소되는 것을 볼 수 있었으며, Curie 온도가 감소하는 결과가 나왔다. 자기 softness 향상은 자화회전에 의한 것이라 여겨진다.다.다.다.

• 대한조선학회지
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• 제16권3호
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• pp.1-8
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• 1979

Various approaches to the analysis of stiffened plating in ship structures have been proposed by a number of researchers. Among them, the finite element method is known to be the most powerful method. However, for many parts of ship's structure having simple geometry and boundary conditions, the F.E.M. is often extravagant and unnecessary. In this paper, the authors have attempted to introduce the finite strip method which was proposed by Y.K. Cheung to avoid the difficulties involved in F.E.M. The results of calculations on the displacements and stresses in various plates with or without stiffeners were satisfactory, which shows the F.S.M. is useful for structural analysis of ship's plating.