• 한국시뮬레이션학회논문지
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• 제23권3호
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• pp.27-32
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• 2014

본 논문에서는, 초고집적 CMOS 회로를 위한 얕은 트랜치 격리로 기존의 수직 구조 보다 개선된 성질을 갖는 새로운 구조를 제안하고자 한다. 이를 위해서 제안한 구조는 회자 모양의 얕은 트랜치 격리 구조이다. 특성 분석은 기존 수직 구조와 제안한 구조에 대해서 전자농도 분포, 열전자 스트레스의 산화막 모양, 전위와 전계 플럭스, 열 손상의 유전 전계와 소자에서 전류-전압 특성을 분석 하고자 한다. 물리적 기본 모델들은 TCAD 툴을 이용하며, 집적화 소자들에 있어서 분석 조건은 주위 조건과 전류와 시간의 인가 스트레스 조건이다. 분석 결과, 얕은 트랜치 격리 구조가 소자의 크기가 감소됨에 따라서 수동적인 전기적 기능이었다. 트랜지스터 응용에서 제안한 회자 구조의 얕은 트랜치 격리 구조가 전기적 특성에서 전위차, 전계, 전자농도 분포가 높게 나타났으며, 활성영역에서 스트레스에 의한 산화막의 영향은 감소되었다. 이 결과 데이터를 바탕으로 소자의 전류-전압 특성 결과 분석도 양호한 특성으로 나타났다.

• Journal of the korean society of oceanography
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• 제37권1호
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• pp.27-34
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• 2002

We measured the alkenone concentration of bulk sediments from a piston core collected from the Ulleung Basin in the East Sea in order to reconstruct past sea surface temperatures (SST). Sediment ages are well constrained by AMS $^{14}C$ dates of the planktonic foraminifera Globigerina bulloides. Coretop alkenone SST calibration with modern surface temperatures and sediment trap dat (Hong et al., 1996) indicate that the SST estimated from alkenones most likely represent the temperatures of late fall. Downcore variations in the alkenone saturation index indicate that between 19 and 15 kyr BP the surface waters were about $3^{\circ}C$ warmer than today. Between 15 and 11 kyr BP, the temperatures were about $3^{\circ}C$ lower than today. A rapid SST increase of about $3^{\circ}C$ occurred at approximately 10 kyr BP. After considering the factors which might influence the SST reconstruction from the $U^{k'}_{37}$ values, we conclude that the alkenone temperature estimates are reliable. The reason for glacial warming in the East Sea is not clear, although there is a possibility that it could be caused by shift in the season of maximum alkenone production from summer during the last glaciation to late fall during the Holocene. Cooling between 15 and 11 kyr BP may be due to inflow of cold water into the East Sea such as via the Oyashio Current or ice-melt water. Warming at the early Holocene could be due to inflow of the Tsushima Current into the East Sea through the Korea Strait.

• 한국세라믹학회지
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• 제40권7호
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• pp.672-676
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• 2003

Y$_3$Fe$_{5}$O$_{12}$(YIG), $Y_3$Fe$_{5}$O$_{12}$(Bi:YIG), TbBi:YIG를 (GdCa)$_3$(GaMgZr)$_{5}$O$_{12}$ (SGGG)기판 위에 Liquid Phase Epitaxy (LPE)법으로 단결정 후막을 성장시켰다. 기판회전속도, 과냉도, 성장시간을 고정하여 치환되는 원소의 종류와 양에 따라 가네트 단결정의 격자상수, Bi 치환양, 표면형상, 자기적 특성을 조사하였다. TbBi:YIG 조성의 경우 격자상수는 12.500 $\AA$으로 기판의 격자상수인 12.496 $\AA$에 근접하게 나타났으며, 포화자계는 150 Oe로 향상된 결과가 나타났다.

• 한국환경과학회지
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• 제9권1호
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• pp.1-11
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• 2000

A study on the variational characteristics of water quality and phytoplankton biomass by principal component analysis(PCA) was carried out in Kogum-sudo from February to October in 1993. We analyzed PCA on biological factors such as chlorophyll a and phytoplankton cell numbers for centric and pennate diatoms, phytoflagellates, and total phytoplankton as well as physico-chemical factors as water temperature, salinity, transparency, dissolved oxygen(DO), saturation of DO, apparent oxygen utilization (AOU), chemical oxygen demand(COD), nutrient (ammonia, nitrite, nitrate, phosphate and silicate), N/P ratio and suspended solid(SS). The source of nutrients supply depended on the mineralization of organic matters and inputs of seawater from outside rather than runoff of freshwater. The phytoplankton biomass was changed within short interval period by nutrients change. And it was controlled by the combination of several environmental factors, especially of light intensity, ammonia and phosphate. The marine environmental characteristics were determined by the mineralization of organic matters in winter, by runoff of freshwater including high nutrients concentration in spring, by ammonia uptake and high phytoplankton productivity in summer, and phosphate supplied input seawater from outside of Kogeum-sudo in autumn. And Kogum-sudo was separated with 2 regions by score distributions of PCA. That is to say, one region was middle parts of straits which was characterized by the mixing seawater and the accumulated organic matters, other one region was Pungnam Bay and the water around Kogum Island which was done by high phytoplankyon biomass and productivity year-round.

• 한국균학회지
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• 제14권3호
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• pp.209-214
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• 1986

버섯중의 trehalase를 연구하기 위하여 각 버섯의 활성을 측정한 후 가장 활성이 좋은 양송이의 trehalase를 $(NH_4)_2SO_4$로 분획하여 조(粗) trehalase의 성질을 조사해 본 결과는 다음과 같다. 1. 조(粗) trehalase는 pH $5.0{\sim}7.0$, $50^{\circ}C$에서 최적 작용조건을 나타내었다. 2. 조(粗) trehalase는 pH $5.0{\sim}7.0$, $50^{\circ}C$이하에서 안정하였다. 3. 조(粗) trehalase의 활성은 490.2mg%이하의 효소농도 및 $2.6{\times}10^{-3}$이하의 기질 농도 범위 내에서 비례적으로 증가하였다. 4. 기질(trehalose) 농도에 대한 Km 값은 0.76 mM이였다. 5. 금속이온에 대한 조(粗) trehalase 활성은 $Sn^{2+}$, $Ca^{2+}$, $Zn^{2+}$, $Hg^{2+}$, $Cd^{2+}$, $Cu^{2+}$, $Mn^{2+}$, $Al^{3+}$, $Fe^{3+}$에 의하여 현저한 저해효과를 나타낸 반면에 $Ag^{+}$, $Ba^{2+}$, $Mg^{2+}$에 의해서는 활성이 증가하였다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.381-384
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• 2002

Response surface methodology (RSM) was successfully applied to optimize for the production of Ganoderma lucidum in batch fermentations using the whey (40,000 mg latose/L) as substrate. This study was performed according to the central composite design (CCD) with respect to pH and temperature, where the designed intervals were 3.3$22.9^{\circ}C$$37.1^{\circ}C$, respectively. A second-order factorial design of the experiments was used to build empirical models providing a quantitative interpretation of the relationships between the two variables. The optimum conditions to maximize the production of G. lucidum were pH 4.2 and $28.3^{\circ}C$. At optimum conditions, the mycelial dry weight (MDW) and residual soluble COD (SCOD) were simultaneously used to evaluate the biokinetic coefficients assocoated with substrate inhibition model by nonlinear least squares method with 95% confidence interval. The. maximum microbial growth rates (${\mu}m$), half saturation coefficient ($K_s$), and the inhibition substrate concentration ($K_{is}$) were determined to be 0.095 l/hr, 128,000 mg SCOD/L and 49,000 mg SCOD/L, respectively. And the microbial yield coefficient (Y), biomass decay rate coefficient ($K_d$), and the maintenance energy coefficient ($m_s$) were determined to be 0.37 mg MDW/mg SCOD, 0.001 1/hr, and 0.0015 1/hr, respectively.

• Environmental Engineering Research
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• 제11권1호
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• pp.1-13
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• 2006

In this study, conventional biofilters packed with flexible synthetic polyurethane (PU) foam carriers were operated to remove toluene from a contaminated air stream. PU foams containing various adsorbents (e.g., zeolite, sepiolite, dolomite and barite) were synthesized for the biofilter media and their adsorption characteristics of toluene were determined. Adsorption capacity of PU-adsorbent foam was in the order of PU-dolomite ${\approx}$ PU-zeolite > PU-sepiolite > PU-barite. During the biofiltration experiment, influent toluene concentration was in the range of 0-160 ppm and EBRT (i.e., empty bed residence time) was 45 seconds. Pressure drop of the biofilter bed was 4-5 mm $H_2O/m$ column height. The maximum removal capacity was in the order of PU-dolomite > PU-zeolite > PU-sepiolite > PU-barite, while the complete removal capacity was in the order of PU-dolomite > PU-sepiolite > PU-zeolite > PU-barite. The better biofiltration performance in PU-dolomite foam was because PU-dolomite foam had lower density and higher porosity than the others providing favorable conditions for microbial growth. The results of biodegradation kinetic analysis showed that PU-dolomite foam had higher maximum removal rate ($V_m\;=\;11.04\;g$ toluene/kg dry material/day) and saturation constant ($K_s\;=\;26.57\;ppm$) than the other PU foams. This supports that PU-dolomite foam was better than the others for biofilteration of toluene.

• Toxicological Research
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• 제17권4호
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• pp.317-323
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• 2001

The skin penetration rate of methidathion in vitro and pharmacokinetics of methidathion in vivo were studied with male Sprague-Dawley rats by dermal treatment. The in vitro skin penetration rates for Sprague-Dawley rats of methidathion technical (50 mg, 100 ${mu}ell$) and emulsifable concentrate (EC,40mg, 100${mu}ell$) were determined as 18.4 $\mu\textrm{g}$/c $m^2$/h (RSD : 6.5) and 18.5 $\mu\textrm{g}$/c $m^2$/h (RSD : 3.2), respectively. Dose-related systemic exposure (AUC) was observed in rats after dermal treatment. The corresponding AUC, $T_{max}$, $C_{max}$, and $T_{1}$2/ of methidathion in plasma were 1.5$\mu\textrm{g}$.hr/ml, 6 h, 0.10 $\mu\textrm{g}$/ml, and 16 h, for 116mg/kg doses, 3.2 $\mu\textrm{g}$. hr/ml, 8 h, 0.12 $\mu\textrm{g}$/ml, and 23 h, for 232 mg/kg doses and 10 $\mu\textrm{g}$. hr/ml, 12 h, 0.32 $\mu\textrm{g}$/ml, and 20 h, for 1,160 mg/kg doses respectively. The urinary excretion of methidathion, estimated wing an equation derived from the in vitro skin penetration study was 0.24~0.35% of the absorbed dose. The concentration of methidathion in kidney was higher than that in liver. Dose-dependent absorption and excretion of methidathion without saturation was observed under in vivo experimental condition.n.n.

• 한국진공학회지
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• 제9권4호
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• pp.400-405
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• 2000

유기금속 소스의 농도를 연속적으로 in-situ 측정이 가능한 EPISON ultrasonic monitor를 이용하여 TMIn(trimethly-indium)의 소스 고갈이 InGaAs, InGaAsP bulk 에피층과 1.55 $mu extrm{m}$ InGaAs/InGaAsP SMQW (strained multi-quantum well)에 미치는 영향을 조사하였다. TMIn 소스는 사용량이 80%에서 급격하게 소스 고갈 현상을 보였다. TMIn 소스는 사용량이 80%에서 급격하게 소스 고갈 현상을 보였다. TMIn 소스 고갈에 의한 에피층의 특성 변화를 조사한 결과, bulk 에피층의 경우에는 소스가 고갈 되기 전에 성장한 에피층과 비교하여 DCXRD(double crystal X-ray diffractometry) spectrum에서 피크 분리가 약 300 arcsec정도 Ga-rich 방향으로 이동하였으며 relative FWHM은 약 2배 가량 증가하는 것을 보였다. SMQW 구조에서는 bulk 에피층과는 달리, PL 중심파장에서도 약 40 nm 정도 단파장쪽으로 이동하였으며, 피크 분리는 약 300 arcsec정도 Ga-rich 방향으로 이동하였다. 하지만, EPISON의 closed loop 기능을 사용할 경우에는 TMIn 소스 사용량이 95%에서도 피크 분리가 $\pm$100 arcsec이내의 재현성 있는 에피층 성장이 가능하다는 것을 알 수 있었다.

• 한국식품과학회지
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• 제17권4호
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• pp.240-244
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• 1985

고려인삼(Panax ginseng C. A.. Meyer) 중의 $\beta$-amylase를 연구하기 위하여 조(粗)인삼 $\beta$-amylase 를 분리한 후 그의 성질을 조사하였다. 조인삼 $\beta$-amylase는 ammonium sulfate 0.2$\sim$0.6포화분획에 의하여 효과적으로 조제되었다. 조제된 본 효소는 전형적인 $\beta$-amylase의 작용을 하여 starch에서 maltose만을 생산하였으며 maltase의 활성은 나타내지 않았다. 본 효소는 pH5$\sim$9(특히 pH7$\sim$8), $40^{\circ}C$ 이하의 조건하에서 안정성을 나타내었고 최적pH 5.0, 최적온도 $35^{\circ}C$를 나타내었다. 본 호소는 기질(starch)농도 l2mg% 이하에서 기질농도에 비례하여 호소활성이 증가하였으며 Km치는 4.76mg%이었다. 또 본 효소는 $K^{+}$, $Na^{+}$, $An^{++}$,$Ca^{++}$, $Co^{++}$,$Mn^{++}$ $Zn^{++}$에는 영향을 받지 않았으나$Ag^{+}$, $Hg^{++}$,$Cd^{++}$, $Cu^{++}$,$ Al^{3+}$, and $Fe^{3+}$ 등에는 현저한 저해를 받았다.