• 한국표면공학회지
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• 제26권2호
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• pp.87-107
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• 1993

The grain size of the final products of WC-Co and WC-Ni composite powders is dependent on the size of the starting material and the conditions employed for the reduction and carburization. APT-Co and -Ni com-plex salts were prepared by the substitution reaction between ammonium ions in APT and the metal ions in Co(NO3)2 and Ni(NO3)2 solutions of different concentrations(0.1 to 0.7M) at $50^{\circ}C$ and the grain sizes of the com-plex salts was $0.54~0.76\mu\textrm{m}$. The complex which calcined the complex salts at $700^{\circ}$~80$0^{\circ}C$ for 60min. were 0.2~0.5$\mu\textrm{m}$. W-Co($5.92^{\circ}C$) and -Ni(6.95%) powders which reduced the complex oxides with H2d atmo-sphere(flow rate;600cc/min.) at $700^{\circ}$~$800^{\circ}C$ for 60min. were $0.5~0.6\mu\textrm{m}$. The mean grain sizes of WC-Co and WC-Ni composite powders which carburized both complex metals of W-Co and W-Ni at $800^{\circ}C$ for 60min. were $0.5~0.6\mu\textrm{m}$, and take place the coarsening of the grain above $800^{\circ}C$ and the optmium ratio of C3H8 and H2 was 0.2 for the control of the free carbon. The effect of Co contents on the particle sizes decreased from 0.4 to $0.25\mu\textrm{m}$ with increasing the content from 2.0 to 7.6w%. The activation energies on the reductions of oxides and the formations of carbides were as follows ; W-Co : Q = 8.7 kcal/mole, W-Ni : Q = 8.1 kcal/mole, WC-Co pow-der : Q = 17.8 kcal/mole, WC-Ni powder : Q = 16.6 kcal/mole.

• 대한수학회보
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• 제49권2호
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• pp.307-317
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• 2012

We say (W, {${\phi}_1,\;{\ldots}\;,{\phi}_t$}) is a polarizable dynamical system of several morphisms if ${\phi}_i$ are endomorphisms on a projective variety W such that ${\otimes}{\phi}_i^*L$ is linearly equivalent to $L^{{\otimes}q}$ for some ample line bundle L on W and for some q > t. If q is a rational number, then we have the equidistribution of small points of given dynamical system because of Yuan's work [13]. As its application, we can build a polarizable dynamical system of an automorphism and its inverse on a K3 surface and can show that its periodic points are equidistributed.

• 대한수학회논문집
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• 제19권2호
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• pp.233-242
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• 2004

The aim of this note is to study properties of the generalized centroid of the semi-prime gamma rings. Main results are the following theorems: (1) Let M be a semi-prime $\Gamma$-ring and Q a quotient $\Gamma$-ring of M. If W is a non-zero submodule of the right (left) M-module Q, then $W\Gamma$W $\neq 0. Furthermore Q is a semi-prime $\Gamma$-ring. (2) Let M be a semi-prime $\Gamma$-ring and $C_{{Gamma}$ the generalized centroid of M. Then $C_{\Gamma}$ is a regular $\Gamma$-ring. (3) Let M be a semi-prime $\Gamma$-ring and $C_{\gamma}$ the extended centroid of M. If $C_{\gamma}$ is a $\Gamma$-field, then the $\Gamma$-ring M is a prime $\Gamma$-ring.

• Kyungpook Mathematical Journal
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• 제51권4호
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• pp.385-393
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• 2011

The aim of this paper is to introduce and study the sequence spaces [w, ${\theta}$, F, p, q]$_{\infty}({\Delta}_{\upsilon}^m)$, [w, ${\theta}$, F, p, q]$_1({\Delta}_{\upsilon}^m)$ and [w, ${\theta}$, F, p, q]$_0({\Delta}_{\upsilon}^m)$, which arise from the notions of generalized difference sequence space, lacunary convergence, invariant mean and a sequence of Moduli $F=(f_k)$. We establish some inclusion relations between these spaces under some conditions.

• 한국식품영양과학회지
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• 제18권1호
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• pp.62-70
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• 1989

본 실험은 식이중에 첨가된 coenzyme Q10이 adriamycin (ADR)을 투여한 흰쥐의 심근 미세 구조에 미치는 영향을 규명하기 위하여 실시되었다. 실험군은 모두 ADR 2수준(1.0mg/kg B.W./week, 2.0mg/kg B.W./week)과 coenzyme Q10 3수준(무첨가군, 0.1g / kg diet 및 0.5g / kg diet)에 의한 6개의 실험군과 basal diet만을 공급하는 대조군을 설정하였다. 체중증가량은 ADR의 투여수준이 높을수록 유의적으로 감소되었으며 식이효율에 있어서는 고수준의 ADR 투여시에만 대조군에 비하여 감소되었다. 그러나 coenzyme Q10에 의한 회복효과는 나타나지 않았다. 혈장내 CPK 활성도는 ADR투여로 약간 증가되었으나 유의적인 차이는 없었으며 coenzyme Q10 급여에 대한 영향은 나타나지 않았다. 전자현미경을 통해 심장조직의 형태적변화를 살펴본 결과 ADR투여로 인해 심근세포내 미세구조의 변성을 관찰할 수 있었고 특히 mitochondria 의 변형, myofibil을 비롯한 세포 소기관의 소실 및 파괴로 빈 공간이 형성되어 있었으나 coenzyme Q10 급여군에서는 그 정도가 약화되었다. 고수준의 ADR 투여는 mitochondria 의 volume density와 surface density를 크게 감소시켰지만 고수준의 coenzyme Q10 급여에 의해 이러한 감소가 조절되었다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.75.2-75.2
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• 2007

• 호남수학학술지
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• 제32권4호
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• pp.563-579
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• 2010

In this paper we introduce the new analogs of Genocchi numbers and polynomials. Finally, we investigate the zeros of the twisted (h,q)-extension of Genocchi polynomials ${G_{n,q,w}^{(h)}}$(x).

• 한국진공학회:학술대회논문집
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• 한국진공학회 2005년도 제28회 학술발표회 초록집
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• pp.46-46
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• 2005

• 한국진공학회:학술대회논문집
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• 한국진공학회 2004년도 제27회 학술발표회 초록집
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• pp.200-200
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• 2004

• 한국진공학회:학술대회논문집
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• 한국진공학회 2007년도 제33회 하계학술대회 초록집
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• pp.290-290
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• 2007