• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.621-625
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• 2015

본 연구에서는 개량형 공압식 가동보를 대상으로 가동보의 기립 각도변화에 따른 잠김흐름에 대한 가동보의 유량계수를 산정하고 흐름특성을 분석하였다. 실험결과, 보의 기립각도의 변화에 대한 위어높이와 위어길이의 비(L/W)가 작을수록 하류수두($H_2$)가 큰 것으로 나타났다. 위어마루에서 하류수면까지의 높이와 위어마루에서 상류 수면고 높이의 비($h_t/H$)에 대한 유량비($Q_s/Q_1$) 변화는 $h_t/H$가 1에 가까울수록 감소하였다. 또한 동일한 $h_t/H$에서 Villemonte(1947)와 Tullis(2007)의 결과와 매우 잘 일치하는 경향을 보여주었다. 따라서 보 하류에서의 수심은 상류보다 작지만 보를 통과하는 흐름으로 인해 하류 유속이 빠르게 나타났으며, 유량이 증가할수록 상 하류 수위차는 감소하는 것으로 나타났다. 또한 같은 유량조건인 경우 하류수두는 L/W가 클수록 크게 증가하였다.

• 대한수학회논문집
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• 제24권2호
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• pp.303-319
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• 2009

Let $Q\;{\in}\;C^2$ : ${\mathbb{R}}\;{\rightarrow}\;[0,{\infty})$ be an even function. Then we will consider the exponential weights w(x) = exp(-Q(x)) in the weight class from [2]. In the paper, we will give some relations among exponential weights in this class and introduce a new weight subclass. In addition, we will investigate some properties of the typical and specific weights in these weight classes.

• 대한수학회보
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• 제34권1호
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• pp.63-79
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• 1997

Consider an oparator equation of the form : $$ (1.1) H[y](x) = \alpha(x)\delta^2 y(x) + \beta(x)\delta y(x) = \lambda_n y(x), $$ where $\alphs(x)$ and $\beta(x)$ are polynomials of degree at most two and one respectively, $\lambda_n$ is the eigenvalue parameter, and $\delta$ is Hahn's operator $$ (1.2) \delta f(x) = \frac{(q - 1)x + \omega}{f(qx + \omega) - f(x)}, $$ for real constants $q(\neq \pm 1)$ and $\omega$.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2002년도 High Temperature Superconductivity Vol.XII
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• pp.47-47
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• 2002

• Journal of the Korean Statistical Society
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• 제20권2호
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• pp.156-161
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• 1991

Exact $D_{s}$-efficient designs for the precise estimation of all the coefficients of the quadratic terms are studied in a quadratic response surface model. Efficient exact designs are constructed for 2 q 5 w.r.t. $D_{s}$-optimaity criterion based on Pesotchinsky's(1975) and approximate $D_{s}$-optimal design given in Lim & Studden(1988) . Moreover, they seem to have reasonably good D-efficiencies. Similar idea could apply to q$\geq$6 cases.

• Archives of Pharmacal Research
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• 제12권3호
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• pp.181-185
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• 1989

When 3-acetyl coumarin derivatives are treated with bromine, 3-(w-bromoacetyl) coumarin derivatives are obtained. The reaction of 3-(w-bromoacetyl)coumarin derivatives with thiourea or with amines for two hours leads to the formation of 2-Amino-4-(3-coumarinyl) thiazole or 3-(w-aminoacetyl) coumarin derivatives, respectively. While 3-(w-bromoacetyl) coumarin derivatives react with amines for 5-8 hours to yield imino derivatives of 3-(w-aminoacetyl) coumarin. The antimicrobial activity of Ia-b, IIa-c, IVc-f, IVh and V$_{c}$, f, h, k, m, and q was studied.d.

• East Asian mathematical journal
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• 제5권2호
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• pp.177-189
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• 1989

• 대한수학회보
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• 제57권5호
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• pp.1143-1149
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• 2020

Sobolev trace inequalities on nonhomogeneous fractional Sobolev spaces are established.

• Reproductive and Developmental Biology
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• 제33권2호
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• pp.113-117
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• 2009

Animals produced by somatic cell nuclear transfer (SCNT) using genetically modified cells are almost always transgenic, implying that this method is more efficient than the traditional pronuclear microinjection method. Most somatic cells for SCNT in animals are fetus-derived primary cells and successful gene integration in somatic cells will depend on transfection condition. The objective of this study is to evaluate the efficiency of electroporation (Microporator) and liposome reagents (F-6, F-HD, W-EX, W-Q, W-M) for tissue-type plasminogen activator (tPA) gene transfection and to estimate the overall efficiency of transfection of Korean native pig fetal fibroblast cells (KNPFF). Electroporation showed significantly higher transfection efficiency than liposome reagents with regard to the transfection of in vitro cultures in the early stages of development (41.7% with Microporator vs. 18.3% with F-6, 20.0% with F-HD 18.5% with W-EX, 5.0% with W-M and 6.3% W-Q,). Colonies identified as tPA-positives were treated once more with G418 for 10 to 14 days and growing colonies were selected again. When the cells of newly selected colonies were subjected to single-cell PCR, reselection of colonies following second round of G418 selection increased the rate of transgene integration per each colony. These results suggest that transfection with electroporation is the most efficient and the second rounds of G418 selection may be an effective method for transfection of porcine fetal fibroblast cells.

• 한국세라믹학회지
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• 제55권4호
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• pp.364-367
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• 2018

The phase evolution, microstructure, and microwave dielectric properties of Sr-substituted $Ba(Mg_{0.5}W_{0.5})O_3$ ceramics, i.e., $(Ba_{1-x}Sr_x)(Mg_{0.5}W_{0.5})O_3$ ($0{\leq}x{\leq}0.30$), sintered at $1700^{\circ}C$ for 1 h were investigated. All compositions showed a 1 : 1 ordered perovskite structure. In all the compositions, $BaWO_4$ was detected as the secondary phase. With increasing x in ($Ba_{1-x}Sr_x$) $(Mg_{0.5}W_{0.5})O_3$, the lattice parameter increased linearly, indicating that a substitutional solid solution occurred. All compositions exhibited a dense microstructure. The value of ${\varepsilon}_r$ increased slightly with increasing x. The value of $Q{\times}f_0$ increased with the increase in x up to x = 0.10 and reached a saturated value of about 100,000 GHz. The composition for x = 0.20, i.e., $(Ba_{0.80}Sr_{0.20})(Mg_{0.5}W_{0.5})O_3$, sintered at $1700^{\circ}C$ for 1 h exhibited superior microwave dielectric properties of ${\varepsilon}_r=19.6$, $Q{\times}f_0=99,358GHz$, and ${\tau}_f=0.0ppm/^{\circ}C$, respectively.