• 한국방사선학회논문지
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• 제15권2호
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• pp.257-263
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• 2021

본 연구는 한국원자력연구원에서 보유하고 있는 100 MeV 선형가속기를 사용하여 천연텅스텐과의 핵반응으로 부터 발생시켜 발생되는 감마선을 측정하여 natW(p,xn)176Re 핵반응에 대한 상대핵반응단면적을 도출하였다. 일반적으로 반감기가 짧은 동위원소에 대한 연구는 항상 짧은 시간 내에 방사능의 강도가 급격하게 작아지는 경향을 보이기 때문에 측정자체가 매우 어려운 것이 현실이다. 특히 176Re의 경우는 반감기가 5.3 분으로 상대적으로 매우 짧은 방사성핵종 중의 하나이다. 본 연구에서는 이런 짧은 반감기를 가지는 176Re 동위원소로부터 발생되는 109.08 keV 감마선을 고순도 Ge검출기를 이용하여 측정하였다. 얻어진 상대 측정값들은 1967년에 Richard G.에 의해 발표된 8 ~ 14 MeV 양성자에너지 영역에서의 결과와 이를 기반으로 계산에 의한 핵반응단면적에 대한 평가한 2019년 A. J. Koning의 결과인 TENDL-2019값과 비교분석하였다. 이 연구의 결과는 미래의 에너지원으로 알려져 있는 핵융합로의 설계, 천체 물리학, 핵의학 및 양성자치료 분야에 요긴하게 활용될 것으로 생각된다.

• KSBB Journal
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• 제19권3호
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• pp.192-199
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• 2004

본 연구에서는 글루타치온의 생산 공정을 개발하기 위해 효모의 성장특성, 글루타치온의 생산성 및 공정 모니터링에 관하여 조사하였다. 초기 pH가 4인 경우 40 mg/L 정도의 높은 글루타치온이 생산되었으며 배양온도에 따른 글루타치온의 생산은 3$0^{\circ}C$에서 가장 높게 나타났다. 그리고 최소 배지에 첨가한 시스테인은 배양 12시간에 넣었을 때 글루타치온의 생산성이 높게 나타났다. 생물 반응기를 이용한 회분식 배양에서 기질 농도에 따른 S. cerevisiae 성장 특성 및 글루타치온 생산은 글루코스 농도 20 g/L에서 글루타치온 생산량이 55 mg/L로 가장 높았다. 최소 배양액에 배양 초기에 0.5 % (v/v) 글라이신과 글루탐산을 각각 첨가하고 배양 11시간에 시스테인을 0.5% (v/v) 추가로 첨가한 경우에 글루타치온의 생산량이 많았다. 회분식 배양 후 기질을 첨가하는 유가식 발효 공정에서는 반응기내 글루코스 농도가 0.5 g/L 이하로 유지되도록 글루코스를 계단식으로 공급하였을 때 글루타치온은 약 102 mg/L로 높은 생산량을 나타내었다. 2차원 형광 센서를 이용하여 글루타치온 생산 공정의 온라인 모니터링은 배양액의 배지 조성이나 성장 특성 등 배양기내의 환경 변화에 따라 형광 영역 및 세기가 다르게 나타났으며 실시간 모니터링 된 형광 데이터는 기질 및 생산물 그리고 균체 성장 등의 각종 공정 변수와 좋은 상관성을 보였다. 따라서 2차원 형광 센서에 의한 모니터링은 글루타치온 대량 생산을 위한 실시간 모니터링에 매우 효과적이라 할 수 있다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2003년도 추계학술발표회초록집
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• pp.119-119
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• 2003

Plasma polymerized organic thin films were deposited on Si(100) glass and Copper substrates at 25 ∼ 100 $^{\circ}C$ using cyclohexane and ethylcyclohexane precursors by PECVD method. In order to compare physical and electrochemical properties of the as-grown thin films, the effects of the RF plasma power in the range of 20∼50 W and deposition temperature on both corrosion protection efficiency and physical properties were studied. We found that the corrosion protection efficiency (P$\_$k/), which is one of the important factors for corrosion protection in the interlayer dielectrics of microelectronic devices application, was increased with increasing RF power. The highest P$\_$k/ value of plasma polymerized ethylcyclohexane film (92.1% at 50 W) was higher than that of the plasma polymerized cyclohexane film (85.26% at 50 W), indicating inhibition of oxygen reduction. Impedance analyzer was utilized for the determination of I-V curve for leakage current density and C-V for dielectric constants. To obtain C-V curve, we used a MIM structure of metal(Al)-insulator(plasma polymerized thin film)-metal(Pt) structure. Al as the electrode was evaporated on the ethylcyclohexane films that grew on Pt coated silicon substrates, and the dielectric constants of the as-grown films were then calculated from C-V data measured at 1㎒. From the electrical property measurements such as I-V ana C-V characteristics, the minimum dielectric constant and the best leakage current of ethylcyclohexane thin films were obtained to be about 3.11 and 5 ${\times}$ 10$\^$-12/ A/$\textrm{cm}^2$ and cyclohexane thin films were obtained to be about 2.3 and 8 ${\times}$ 10$\^$-12/ A/$\textrm{cm}^2$.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1427-1439
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• 2008

The quality of track-bed fills of railways has been controlled by field measurements of density (${\gamma}_d$) and the results of plate-load tests. The control measures are compatible with the design procedures whose design parameter is $k_{30}$ for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures is that there are no simple laboratory measurement procedures for the design parameters ($k_{30}$ or, $E_{v2}$ and $E_{v2}/E_{v1}$) in design stage. A new quality control procedure, in parallel with the advent of the new design procedure, is being proposed. This procedure is based upon P-wave velocity involving consistently the evaluation of design parameters in design stage and the field measurements during construction. The key concept of the procedure is that the target value for field compaction control is the P-wave velocity determined at OMC using modified compaction test, and direct-arrival method is used for the field measurements during construction. The procedure was verified at a test site and the p-wave velocity turned out to be an excellent control measure. The specifications for the control also include field compaction water content of $OMC{\pm}2%$ as well as the p-wave velocity.

• KSBB Journal
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• 제28권2호
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• pp.65-73
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• 2013

This study aimed to investigate the enzymatic hydrolysis of mannitol using Viscozyme$^{(R)}$ L, Celluclast$^{(R)}$ 1.5 L, Saczyme$^{(R)}$, Novozym$^{(R)}$, Fungamyl$^{(R)}$ 800 L, Driselase$^{(R)}$ Basidiomycetes sp., and Alginate Lyase, and to optimize of reaction conditions for production of reducing sugar. Response surface methodology (RSM) based on central composite rotatable design was used to study effects of the independent variables such as enzyme (1-9% v/w), reaction time (10-30 h), pH (3.0-7.0) and reaction temperature ($30-70^{\circ}C$) on production of reducing sugar from mannitol. The coefficient of determination ($R^2$) of $Y_1$ (yield of reducing sugar by Viscozyme$^{(R)}$ L) and $Y_3$ (yield of reducing sugar by Saczyme$^{(R)}$) for the dependent variable regression equation was analyzed as 0.985 and 0.814. And the p-value of $Y_1$ and $Y_3$ showing 0.000 and 0.001 within 1% (p < 0.01), respectively, was very significant. The optimum conditions for production of reducing sugar with Viscozyme$^{(R)}$ L were 9.0 % (v/w) amount of enzyme, 30.0 hours of reaction time, pH 4.5 and $30.0^{\circ}C$ of reaction temperature, and those with Saczyme$^{(R)}$ were 9.0% (v/w) of amount of enzyme dosage, 30.0 h of reaction time, pH 7.0 and $30.0^{\circ}C$ of reaction temperature, consequently, the predicted reducing sugar yields were 22.5 and 27.9 mg/g-mannitol, respectively.

• Design & Manufacturing
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• 제14권3호
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• pp.8-16
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• 2020

In this study, the vibration signal of the mold was measured and analyzed to monitoring the process time and characteristics during injection molding. A 5 inch light guide plate mold was used to injection molding and the vibration signal was measured by MPU6050 acceleration sensor module attached the surface of fixed mold base. Conditions except for injection speed and packing pressure were set to the same value and the change of the vibration signal of the mold according to injection speed and packing pressure was analyzed. As a result, the vibration signal had a large change at three points: "Injection start", "V/P switchover", and "Packing end". The time difference between "injection start" and "V/P switchover" means the injection time in the injection molding process, and the time difference between "V/P switchover" and "Packing end" means the packing time. When the injection time and packing time obtained from the vibration signal of the mold are compared with the time recorded in the injection molding machine, the error of the injection time was 2.19±0.69% and the error of the packing time was 1.39±0.83%, which was the same level as the actual value. Additionally, the amplitude at the time of "injection start" increased as the injection speed increased. In "V/P switchover", the amplitude tended to be proportional to the pressure difference between the maximum injection pressure and the packing pressure and the amplitude at the "packing end" tended to the pressure difference between the packing pressure and the back pressure. Therefore, based on the result of this study, the injection time and packing time of each cycle can be monitored by measuring the vibration signal of the mold. Also, it was confirmed that the level and trend of process variables such as the injection speed, maximum injection pressure, and packing pressure can be evaluated as the change of the mold vibration during injection molding.

• 한국미생물·생명공학회지
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• 제25권1호
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• pp.56-61
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• 1997

An alkaline protease producing microorganism was isolated from korean traditional Meju and identified as Scopulariopsis brevicaulis. The optimum culture condition of Scopulariopsis brevicaulis for the production of alkaline protease was as follow: 2% soluble starch, 0.2$, tryptophan, 0.1% (NH$_{4}$) $_{2}$S$_{2}$O$_{8}$ 0.2% NaHPO$_{4}$, pH 7.5, 35$\CIRC $C. The optimum pH and temperature for the enzyme activity of alkaline protease producing Scopulariopsis brevicaulis were pH 9.0 and 50$\circ $C, respectively. The enzyme was relatively stable at pH 6.0~11.0 and at temperature below 40$\circ $C. The activity of the enzyme was inhibited by Hg$^{2+}$ whereas Cu$^{2+}$ gave rather activating effects on the enzyme activity. Phenylmethanesulfonyl fluoride inhibited the enzyme activity. This result indicates that serine is very important role in this enzyme. Km value for casein was 1.2410$^{4}$ M/L, V$_{max}$ value for casein was 25.99 $\mu $g/min. This enzyme hydrolyzed casein more rapidly than the hemoglobin.

• 한국환경보건학회지
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• 제29권2호
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• pp.23-28
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• 2003

To evaluate the effect of cyclohexane(CH) treatment on the liver cytochrome P-450 dependent aniline hydroxylase(CYPdAH) activity in alcohol-pretreated animals, CH(1.56 g/kg body weight) was intraperitoneally administered to Sprague-Dawley male rats, which had been drunk 15％ alcohol in distilled water for 1,3 and 6 weeks. CH was injected to rats 4 times every other day and the animals were sacrificed at 24 hours after injection of CH. In the alcohol-pretreated rats, liver injuries were not demonstrated on the basis of the liver weight per body weight, the levels of serum alanine aminotransferase and hepatic microsomal glucose-6-phosphatase activities. By the CH treatment, alcohol-pretreated animals showed the significantly increased activity of hepatic microsomal CYPdAH. Concomitantly $V_{max}$ value in CYPdAH was more increased, whereas $K_{M}$ value more decreased in alcohol-pretreated animals by the treatment of CH. In conclusion, the increasing cause of microsomal CYPdAH in CH-treated rats pretreated with alcohol may be due to induction of enzyme protein in rat liver.r.r.

• Asian-Australasian Journal of Animal Sciences
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• 제26권6호
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• pp.886-895
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• 2013

This study was conducted to explore the antioxidant potential and functional value of guava (Psidium guajava L.) powder in muscle foods. Guava powder was used as a source of antioxidant dietary fibre in sheep meat nuggets at two different levels i.e., 0.5% (Treatment I) and 1.0% (Treatment II) and its effect was evaluated against control. Guava powder is rich in dietary fibre (43.21%), phenolics (44.04 mg GAE/g) and possesses good radical scavenging activity as well as reducing power. Incorporation of guava powder resulted in significant decrease (p<0.05) in pH of emulsion and nuggets, emulsion stability, cooking yield and moisture content of nuggets while ash and moisture content of emulsion were increased. Total phenolics, total dietary fibre (TDF) and ash content significantly increased (p<0.05) in nuggets with added guava powder. Product redness value was significantly improved (p<0.05) due to guava powder. Textural properties did not differ significantly except, springiness and shear force values. Guava powder was found to retard lipid peroxidation of cooked sheep meat nuggets as measured by TBARS number during refrigerated storage. Guava powder did not affect sensory characteristics of the products and can be used as source of antioxidant dietary fibre in meat foods.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.269-277
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• 1998

This in vitro study compared the microleakage of 4 lining conditions when used with Gallium alloy GF II and Valiant PhD. Class V cavity was prepared on both buccal and lingual surface of 80 extracted human premolar & molar teeth with one margin in enamel and another in dentin. Before restoration, prepared cavities were applied to no-liner, cavity varnish, Scotchbond multipurpose, and Superbond D-liner II plus according to manufacture's instructions. The restored teeth were stored in saline for 1 week, then thermocycled for 100 times, stained with 0.5% basic fuchsin dye for 1 day, sectioned, and observed using a light microscope. Following results were obtained. 1. The leakage value of Superbond-lined group showed significantly lower than that of nolined group on both margins of Valiant PhD(p<0.05). 2; There was no significant difference between the 4 lining conditions in Gallium alloy GF II (p>0.05). 3. When We make a comparison between Gallium alloy GF II and Valiant PhD under same lining conditions, the microleakage value of Gallium alloy GF II showed lower than that of Valiant PhD on occlusal & gingival margin(p<0.05) except for Superbond-lined group(p>0.05).