• 한국전기전자재료학회논문지
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• 제15권5호
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• pp.435-440
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• 2002

In this study, we have investigated photo-induced changes of optical energy gap( $E_{OP)}$ and photoluminescence (PL) in amorphous ($\alpha$-) S $e_{100-x}$G $e_{x}$ (x=5, 25 and 33) thin films prepared by conventional thermal evaporation method. In the $\alpha$-S $e_{100-x}$G $e_{x}$ thin film, the $E_{OP}$ is obtained by a linear extrapolation of the ($\alpha$hν)$^{\frac{1}{2}}$ versus hν plot to the energy axis using the optical absorption coefficient ($\alpha$) calculated from the extinction coefficient k measured in the wavelength range of 290~900nm. Although the values of $\Delta$ $E_{OP}$ are very different, all films exhibit photo-induced photo-darkening (PD) effect that is a red shift of $E_{OP}$ . In particular, $\Delta$ $E_{OP}$ in $\alpha$-S $e_{75}$ G $e_{25}$ thin film exhibits the largest value (i, e., $\Delta$ $E^{OP}$ ~40meV for $\alpha$-S $e_{95}$ G $e_{5}$ , $\Delta$ $E_{OP}$ ~200meV for $\alpha$-S $e_{75}$ G $e_{25}$ , $\Delta$ $E_{OP}$ ~130meV for $\alpha$-S $e_{67}$ G $e_{33}$ ). PL spectra in $\alpha$-SeGe by hν$_{HeCd}$ have no-Stokes shift (SS) and show a tendency dependent on both composition and illumination time. We explain the energy-induced phenomena such as the PD and thermal bleaching, the native charged-defect generation and the no-SS PL, etc..the PD and thermal bleaching, the native charged-defect generation and the no-SS PL, etc..tc..

• Reproductive and Developmental Biology
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• 제34권1호
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• pp.47-53
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• 2010

Glycoprotein hormones have a common $\alpha$-subunit that is involved in the signaling pathway together with G protein, adenylcyclase and cAMP induction; however, it is an unclear how this common structure is related to hormonal action. To determine the biological functions of the COOH-terminal amino acids in the $\alpha$-subunit of these glycoprotein hormones, a tethered-molecule was constructed by fusing the $NH_2$-terminus of the $\alpha$-subunit to the COOH-terminus of the $\beta$-subunit of equine chorionic gonadotropin (eCG). The following deletion mutants were created by PCR; Ile was inserted at position 96 to form ${\Delta}96$, Lys was substituted at position 95 to form ${\Delta}95$, His was inserted at position 93 to form ${\Delta}93$ and Tyr was substituted at position 87 to form ${\Delta}87$. Each mutant was transfected into CHO-K1 cells. Tethered-wt eCG, and ${\Delta}96$, ${\Delta}95$, and ${\Delta}93$ mutants were efficiently secreted into the medium but the ${\Delta}87$ mutant was not secreted. Interestingly, the RT-PCR, real-time PCR, and northern blot analyses confirmed that the RNA was transcribed in the ${\Delta}87$ mutant. However, the ${\Delta}87$ mutant protein was not detected in the medium or the intracellular fraction of the cell lysates. The LH- and FSH-like activities of the recombinant proteins were assayed in terms of cAMP production using rat LH/CG and rat FSH receptors. The metabolic clearance rate (MCR) was determined by injecting rec-eCG (2 IU) into the tail vein. The ${\Delta}95$ and ${\Delta}93$ mutants were completely inactive in both the LH- and FSH-like activity assays. The ${\Delta}96$ mutant showed slight activity in the LH-like activity assay. In comparison to the wild type, the activity of the ${\Delta}96$ mutant in the FSH-like activity assay was the highest among all the mutants. The MCR assay in which rec-eCG was injected showed a peak at 10 min in all the treatment groups, which disappeared 4 h after injection. These results imply a direct interaction between the receptor and the COOH-terminal region of the a-subunit. The data also reveal a significant difference in the mechanism by which the eCG hormone interacts with the rLH and rFSH receptors. The COOH-terminal region of the $\alpha$-subunit is very important for the secretion and functioning of this hormone.

• 한국세라믹학회지
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• 제38권11호
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• pp.1015-1022
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• 2001

본 연구에서는 용융염법에 의한 Ba-ferrite의 생성기구와 그 자기적특성에 대해 조사하였다. 출발원료 중 BaC $O_3$만이 용융염내에서 용해도를 가졌으며, 이는 용융염내에서는 Ba-ferrite의 생성이 용해된 $Ba^{2+}$가 F $e_2$ $O_3$나 $\delta$-FeOOH의 표면으로 확산하여 표면반응을 통해 일어나는 것으로 보인다. 한편, 출발물질($\delta$-FeOOH와 F $e_2$ $O_3$)에 따라 생성된 Ba-ferrite가 합성되는 온도는 더 낮은 온도에서 생성됨을 알 수 있었다.

• Transactions on Electrical and Electronic Materials
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• 제10권4호
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• pp.125-130
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• 2009

The clamping voltage characteristics and accelerated aging behavior of CoCrTb-doped Zn/Pr-based varistors were investigated for different sintering temperatures. The best clamping voltage characteristics were obtained for the varistors sintered at $1330^{\circ}C$, with a clamping voltage ratio (K) of 1.63 at a surge current of 5 A and 1.75 at a surge current of 10 A. The varistors sintered at $1330^{\circ}C$ exhibited the highest stability, with -0.1% in $%{\Delta}E_{1\;mA}$, -0.2% in $%{\Delta}{\alpha}$, and +15.5% in $%{\Delta}J_L$ for E-J characteristics under a stress state of 0.90 $E_{1\;mA/120^{\circ}C$ /24 h. Furthermore, it exhibited $%{\Delta}{\varepsilon}_{APP}$' of -0.7% and $%{\Delta}tan{\delta}$ of +5.7% for dielectric characteristics under the same stress state.

• 천문학회지
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• 제15권2호
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• pp.49-58
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• 1982

The UBVRIHKL magnitudes on Johnson system and space motions of M dwarf stars have been collected. This sample of M stars have been distinguished on a purely kinematical basis; the one with e<0.15, young disk population, with 0.150.3 halo population. On the color-color diagrams and the color excess-orbital eccentricity diagrams, there is no distinction between the old disk stars and the young disk stars. However (I-H) color could be used to distinguish halo stars from young and old disk stars and the color excesses, ${\Delta}(U-B),\;{\Delta}(B-V),\;{\Delta}(V-R),\;{\Delta}(H-K),\;{\Delta}(K-L),\;and\;{\Delta}(B-R)$ can be used as abundance indicators only for the halo stars. But these color excesses which are measures of blue excesses, are positive for the halo stars with smaller eccentricities and become negative for those with larger eccentricities.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.404-407
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• 1993

In this paper, a new PID fuzzy controller(FC) is presented. The linguistic control rules of PID FC is separated into two parts : one is e-.DELTA.e part, and the other is .DELTA.$^{2}$e - .DELTA.e part. And then two FCs employing these rule base individually are synthesized. The control input to the process is decided by taking weighted mean of the outputs of two FCs. The proposed PID FC improve the transient response of the system and gives better performance than the conventional PI FC.

• 산업기술연구
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• 제13권
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• pp.43-48
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• 1993

In this paper, a new PID fuzzy controller (FC) is presented. The linguistic control rules of PID FC is separated into two parts : one is $e-{\Delta}e$ part, and the other is ${\Delta}^2e-{\Delta}e$ part. And then two FCs employing these rule base indivisually are synthesized. The control input to the process is decided by taking weighted mean of the outputs of two FCs. The proposed PID FC improve the transient response of the system and gives better performance than the conventional PI FC.

• Journal of applied mathematics & informatics
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• 제24권1_2호
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• pp.357-366
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• 2007

Let G(V, E) be a simple graph, and let f be an integer function on V with $1{\leq}f(v){\leq}d(v)$ to each vertex $v{\in}V$. An f-edge cover-coloring of a graph G is a coloring of edge set E such that each color appears at each vertex $v{\in}V$ at least f(v) times. The f-edge cover chromatic index of G, denoted by ${\chi}'_{fc}(G)$, is the maximum number of colors such that an f-edge cover-coloring of G exists. Any simple graph G has an f-edge cover chromatic index equal to ${\delta}_f\;or\;{\delta}_f-1,\;where\;{\delta}_f{=}^{min}_{v{\in}V}\{\lfloor\frac{d(v)}{f(v)}\rfloor\}$. Let G be a connected and not complete graph with ${\chi}'_{fc}(G)={\delta}_f-1$, if for each $u,\;v{\in}V\;and\;e=uv{\nin}E$, we have ${\chi}'_{fc}(G+e)>{\chi}'_{fc}(G)$, then G is called an f-edge covered critical graph. In this paper, some properties on f-edge covered critical graph are discussed. It is proved that if G is an f-edge covered critical graph, then for each $u,\;v{\in}V\;and\;e=uv{\nin}E$ there exists $w{\in}\{u,v\}\;with\;d(w)\leq{\delta}_f(f(w)+1)-2$ such that w is adjacent to at least $d(w)-{\delta}_f+1$ vertices which are all ${\delta}_f-vertex$ in G.

• 대한화학회지
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• 제37권6호
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• pp.555-561
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• 1993

메탄올용매내에서 요오드와 테트라메틸주석 사이의 Iododestannylation에 대한 반응속도를 분광학적 방법으로 연구하였다. 이 결과로부터 일시적인 전하이동착물의 흡수 스펙트럼이 관찰되었으며, 흡수 스펙트럼의 후속적인 감소현상으로 요오드에 의한 테트라메틸주석의 분해반응임을 알았다. 따라서 iododestannylation에 대한 속도상수를 온도 10, 25 및 35$^{\circ}C$ 압력을 1600 bar 까지 변화시켜 가면서 측정하였으며, 이때의 반응속도상수는 온도와 압력에 따라 증가함을 알았다. 이 반응속도상수로부터 ${\Delta}V^\neq,\;{\Delta}{\beta}^{\neq},\;{\Delta}H^{\neq},\;{\Delta}S^{\neq}$ 및 ${\Delta}G^{\neq}$의 값을 구하였다. 활성화 부피와 활성화 압축율계수는 모두 음의 값이며, 활성화 엔탈피는 양의 값을, 활성화 엔트로피는 음의 값을 나타내었다. 이들 값으로부터 전이상태의 용매구조변화 및 메카니즘을 규명하였다. 이러한 사실로부터 본 반응은 $S_E2$ 메카니즘이 지배적이며 압력이 증가함에 따라 $S_E2$의 성격이 약화됨을 알았다

• 대한화학회지
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• 제8권4호
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• pp.142-146
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• 1964

The author proposed an equation of fading rate, expressed as ${\Delta}E$=${\Delta}E_{1{\infty}}({{1-e^{-k}}_1}^t)+k_2t$, where ${\Delta}E$=fading of dye (colour difference of N.B.S. unit), ${\Delta}E_{1{\infty}}$=extremity value of fading of molecularly dispersed dye, $k_1$, $k_2$=constants, t=exposure (hours). The validity of above equation, which is connected with the state of dye in fibre, was confirmed by experimental in a range of 2-3 colour fading in grey scale value for assessing change in colour visually, except the case of increasing the fading rate with the time resulted from the break-down of dye particles through the heat effect of light; it was also discussed about possiblity of evaluating of fastness to light of dye in early stage.