• 대한수학회보
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• 제55권4호
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• pp.1093-1101
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• 2018

Let (RDTF, M) be a Milnor square. In this paper, it is proved that R is a ${\mathcal{C}}$-hereditary domain if and only if both D and T are ${\mathcal{C}}$-hereditary domains; R is an almost perfect domain if and only if D is a field and T is an almost perfect domain; R is a Matlis domain if and only if T is a Matlis domain. Furthermore, to give a negative answer to Lee, s question, we construct a counter example which is a C-hereditary domain R with $w.gl.dim(R)={\infty}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.197-200
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• 2001

In this letter, we report on the investigation of Ni/Si/Ni Ohmic contacts to n-type 4H-SiC. Ohmic contacts have been formed by a vacuum annealing and $N_2$ gas ambient annealing method at $950^{\circ}C$ for 10 min. The specific contact resistivity ( $\rho_{c}$ ), sheet resistance($R_s$), contact resistance($R_c$), transfer length($L_T$) were calculated from resistance($R_T$) versus contact spacing(d) measurements obtained from 10 TLM(transmission line method) structures. The resulting average values of vacuum annealing sample were $\rho_{c}=3.8{\times}10^{-5}\Omega cm^{3}$, $R_{c}=4.9{\Omega}$, $R_{T}=9.8{\Omega}$ and $L_{T}=15.5{\mu}m$, resulting average values of another sample were $\rho_{c}=2.29{\times}10^{-4}\Omega cm^{3}$, $R_{c}=12.9{\Omega}$ and $R_{T}=25.8{\Omega}$. The physical properties of contacts were examined using X-Ray Diffraction and Auger analysis, there was a uniform intermixing of the Si and Ni, migration of Ni into the SiC.

• 대한수학회논문집
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• 제37권1호
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• pp.229-257
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• 2022

Let M be a semi-invariant submanifold of codimension 3 with almost contact metric structure (𝜙, 𝜉, 𝜂, g) in a complex space form M_n+1(c), c ≠ 0. We denote by A and R_𝜉 the shape operator in the direction of distinguished normal vector field and the structure Jacobi operator with respect to the structure vector 𝜉, respectively. Suppose that the third fundamental form t satisfies dt(X, Y) = 2𝜃g(𝜙X, Y) for a scalar 𝜃(< 2c) and any vector fields X and Y on M. In this paper, we prove that if it satisfies R_𝜉A = AR_𝜉 and at the same time ∇_𝜉R_𝜉 = 0 on M, then M is a Hopf hypersurface of type (A) provided that the scalar curvature s of M holds s - 2(n - 1)c ≤ 0.

• 충청수학회지
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• 제30권1호
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• pp.77-102
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• 2017

As an analogy of $Poincar{\acute{e}}$ series in the space of modular forms, T. Ono associated a module $M_c/P_c$ for ${\gamma}=[c]{\in}H^1(G,R^{\times})$ where finite group G is acting on a ring R. $M_c/P_c$ is regarded as the 0-dimensional twisted Tate cohomology ${\hat{H}}^0(G,R^+)_{\gamma}$. In the case that G is the Galois group of a Galois extension K of a number field k and R is the ring of integers of K, the vanishing properties of $M_c/P_c$ are related to the ramification of K/k. We generalize this to arbitrary n-dimensional twisted cohomology of the ring of integers and obtain the extended version of theorems. Moreover, some explicit examples on quadratic and biquadratic number fields are given.

• 한국약용작물학회지
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• 제23권3호
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• pp.245-252
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• 2015

This study was carried out to investigate the effects of Salvia plebeia R. Br. ethanolic extract with different aspects (stem/leaf and whole plant) on differentiation and lipid accumulation in 3T3-L1 preadipocytes. The morphological changes and the degrees of lipid accumulation in 3T3-L1 cells were measured by Oil Red O staining and intra-cellular triglyceride (TG) assay. The mRNA expressions of special peroxisome proliferation activated receptor- genes (PPAR), CCAAT/ enhancer-binding protein (C/$EBP{\alpha}$), fatty acid synthase (FAS) and lipoprotein lipase (LPL) were detected by reverse transcriptase polymerase chain reaction (RT-PCR). The 50% ethanolic extracts ($100{\mu}g/mL$) of stem and leaf (SALE) and 30% ethanolic extracts (100 g/mL) of whole plant (SAE) from Salvia plebeia R. Br. were significantly attenuated lipid accumulation during adipogenesis in 3T3-L1 cells. Ethyl acetate-soluble fractions ($50{\mu}g/mL$) significantly inhibited lipid droplet accumulation in 3T3-L1 cells. In addition, SALE induced down-regulation of specific adipogenic transcriptional factors (C/$EBP{\alpha}$ and $PPAR{\gamma}$) and target genes (FAS and LPL) during adipogenesis. Salvia plebeia R. Br. may be used as a safe and efficient natural substance to manage obesity.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1613-1617
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• 2006

The total light efficiencies of the novel 1.9" transflective tRGB-t/rW and tRGB-rW TFT LCDs are calculated and they are implemented by the traditional 7-mask ${\alpha}$-Si processing. Then, the two vehicles are turned on with the appropriate Sub-Pixel Rendering White (SPRW) algorithms, so they can exhibit the extra luminance without the original visual resolution loss. Their outstanding optical properties are approved by measuring the contrast ratio (C.R.) and the NTSC ratio. Because they utilize the light resource very effectively and efficiently, they are very suitable for the dark indoor and the bright outdoor environments.

• 한국수산과학회지
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• 제56권3호
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• pp.331-340
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• 2023

To estimate the biological reference points, suitable for fisheries management of sandfish Arctoscopus japonicas in the East Sea of Korea, we simulated the yield-per-recruit (Y/R) from age 0 to 6 (0-2,555 days). The stimulation was based on two instantaneous natural mortality conditions: size-dependent (M_t, d^-1) and constant (M_cons, d^-1); Subsequently, the biological reference points of the two mortality conditions was compared. M_t decreased from 0.0075 d^-1 to 0.0018 d^-1 depending on growth, and M_cons remained constant at 0.0011 d^-1 for all ages. Our Y/R model showed that the maximum yield of M_cons was 14 times higher than that of the M_t. The length at first capture to maximize the harvest at the F_0.1 points of the two natural mortality conditions was L_c,t=10.2 cm (TL) and L_c,cons=17 cm (TL). We concluded that M_t was more suitable for estimating M than M_cons; this is because L_c,t showed minimal difference from the current fishing regulations (11 cm, TL), and M_t reflected more biological characteristics than M_cons. We suggest that 10.2 cm and 0.8 as the suitable length at first capture and corresponding age, respectively for efficient fisheries management of sandfish.

• East Asian mathematical journal
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• 제38권5호
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• pp.549-581
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• 2022

Let M be a semi-invariant submanifold with almost contact metric structure (𝜙, 𝜉, 𝜂, g) of codimension 3 in a complex space form M_n+1(c), c≠ 0. We denote by S and R_𝜉 be the Ricci tensor of M and the structure Jacobi operator in the direction of the structure vector 𝜉, respectively. Suppose that the third fundamental form t satisfies dt(X, Y) = 2𝜃g(𝜙X, Y) for a certain scalar 𝜃(≠ 2c) and any vector fields X and Y on M. In this paper, we prove that M satisfies R_𝜉S = SR_𝜉 and at the same time R_𝜉𝜙 = 𝜙R_𝜉, then M is a Hopf hypersurface of type (A) provided that the scalar curvature s of M holds s - 2(n - 1)c ≤ 0.

• East Asian mathematical journal
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• 제37권1호
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• pp.41-77
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• 2021

Let M be a semi-invariant submanifold of codimension 3 with almost contact metric structure (��, ξ, η, g) in a complex space form Mn+1(c), c ≠ 0. We denote by Rξ = R(·, ξ)ξ and A(i) be Jacobi operator with respect to the structure vector field ξ and be the second fundamental form in the direction of the unit normal C(i), respectively. Suppose that the third fundamental form t satisfies dt(X, Y ) = 2��g(��X, Y ) for certain scalar ��(≠ 2c)and any vector fields X and Y and at the same time Rξ is ��∇ξξ-parallel, then M is a Hopf hypersurface in Mn(c) provided that it satisfies RξA(1) = A(1)Rξ, RξA(2) = A(2)Rξ and ${\bar{r}}-2(n-1)c{\leq}0$, where ${\bar{r}}$ denotes the scalar curvature of M.

• 한국양식학회지
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• 제10권1호
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• pp.25-32
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• 1997

코끼리조개의 인공종묘생산 기술개발의 일환으로 성숙된 모패를 절개법에 의하여 인공수정시켜 난 발생 및 유생의 발달과정을 관찰한 결과를 요약하면 다음과 같다. 코끼리조개의 난은 분리침성란으로 나타났으며, 방란직후 알의 모양은 타원형이나 수정이 되면 직경 $70\mu$m의 구형으로 된다. 수정난의 발생은$ 11^{citc}C$에서 4시간 후 4세포기로 되고, 2일이 지나면 담륜자 유생(trochophore larvae), 수정 후 3일째에는 D상 유생, 23일째에는 각정기, 36일째에는 성숙유생으로 되었다. 수온(w)에 따른 각 단계별 소요시간(t)의 관계를 보면, 8세포 : 1/t=0.0209 w-0.1167 (r=0.9967) 포배기 : 1/t=0.0055 w-0.0192 (r=0.9825) 담륜자기 : 1/t=0.0034 w-0.0155 (r=0.9907) D상 유생기 : 1/t=0.0014 w-0.0023 (r=0.9843) 상기 식에서 산출된 코끼리조개의 생물학적 기초수온은 3.82$^{\circ}C$였다.