• Nuclear Engineering and Technology
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• 제45권1호
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• pp.53-60
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• 2013

Bentonite is generally used as a buffer material in high-level radioactive waste disposal facilities and consists of 50% quartz by weight. Quartz strongly affects the behavior of bentonite over very long periods. For this reason, quartz dissolution experiment was performed under high-pressure and high-alkalinity conditions based on the conditions found in a high-level radioactive waste disposal facility located deep underground. In this study, two quartz dissolution experiments were conducted on 1) quartz beads under low-pressure and high-alkalinity conditions and 2) a single quartz crystal under high-pressure and high-alkalinity conditions. Following the experiments, a confocal laser scanning microscope (CLSM) was used to observe the surfaces of experimental samples. Numerical analyses using the finite element method (FEM) were also performed to quantify the deformation of contact area. Quartz dissolution was observed in both experiments. This deformation was due to a concentrated compressive stress field, as indicated by the quartz deformation of the contact area through the FEM analysis. According to the numerical results, a high compressive stress field acted upon the neighboring contact area, which showed a rapid dissolution rate compared to other areas of the sample.

• ETRI Journal
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• 제27권6호
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• pp.691-696
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• 2005

In asynchronous transfer mode (ATM) networks, fixed length cells of 53 bytes are transmitted. A cell may be discarded during transmission due to buffer overflow or a detection of errors. Cell discarding seriously degrades transmission quality. The quality degradation can be reduced by employing efficient forward error control (FEC) to recover discarded cells. In this paper, we present the design and implementation of decoding equipment for FEC in ATM networks based on a single parity check (SPC) product code using very-large-scale integration (VLSI) technology. FEC allows the destination to reconstruct missing data cells by using redundant parity cells that the source adds to each block of data cells. The functionality of the design has been tested using the Model Sim 5.7cXE Simulation Package. The design has been implemented for a $5{\times}5$ matrix of data cells in a Virtex-E XCV 3200E FG1156 device. The simulation and synthesis results show that the decoding function can be completed in 81 clock cycles with an optimum clock of 56.8 MHz. A test bench was written to study the performance of the decoder, and the results are presented.

• 전기화학회지
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• 제5권4호
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• pp.209-211
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• 2002

The simultaneous sensing of nitric oxide (NO) and its metabolite, nitrite $(NO_2^-)$ has been studied by Osteryoung square-wave voltarnmetery (OSWV) in physiological pH solution (0.1 M phosphate buffer solution, pH 7.2). Using an electrochemically pretreated glassy carbon (GC) electrode, OSWV was successfully applied to observe the well-separated oxidation peaks at ca. 0.58 and 0.80V vs. Ag/AgCI for NO and $(NO_2^-)$, respectively. This clear separation between the NO and $(NO_2^-)$ oxidation peaks may be due to the formation of surface oxides (e.g., quinone (C=O) or carboxylic $(COO^-)$ group) and surface defects introduced by the electrochemical pretreatment of GC electrodes.

• ETRI Journal
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• 제39권5호
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• pp.683-694
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• 2017

Several studies have focused on multimedia transmission over wireless sensor networks (WSNs). In this paper, we propose a comprehensive and robust model to transmit images over cognitive radio WSNs (CRWSNs). We estimate the spectrum sensing frequency and evaluate its impact on the peak signal-to-noise ratio (PSNR). To enhance the PSNR, we attempt to maximize the number of pixels delivered to the receiver. To increase the probability of successful image transmission within the maximum allowed time, we minimize the average number of packets remaining in the send buffer. We use both single- and multi-channel transmissions by focusing on critical transmission events, namely hand-off (HO), No-HO, and timeout events. We deploy our advanced updating method, the dynamic parameter updating procedure, to guarantee the dynamic adaptation of model parameters to the events. In addition, we introduce our ranking method, named minimum remaining packet best channel selection, to enable us to rank and select the best channel to improve the system performance. Finally, we show the capability of our proposed image scrambling and filtering approach to achieve noticeable PSNR improvement.

• 한국결정학회지
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• 제7권2호
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• pp.120-125
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• 1996

Salmonella typhimurium LT2에서 deoxy-thymidine diphosphate-D-gluxose-4,6-dehydratase의 유전자를 재조합한 Escherichia coli BL21 clone으로부터 dTDP-D-glucose dehydratase를 분리 정제한 후, 이 효소의 단결정을 상온에서 sitting drop 기체확산법으로 성장시켰다. 결정은 효소에 기질이 포함되어 있는 것과 포함되어 있지 않는 것 모두가 얻어지며, 이 때 침전제는 1.6-2.0 M Na, K 인산 완충용액(pH 8.0)을 사용하였다. 이 단결정은 최소 2.5Å의 분해능으로 회절하였으며, 공간군은 hexagonal한 P61이고, 격자의 크기는 a=b=168.54Å, c=81.08Å이었다. Asymmetric unit에는 이량체 한분자를 포함하고 있으며 단백질 질량당 결정의 부피는 VM=2.4Å3/Da, 용매의 함유율은 부피를 기준으로 64%였다.

• 약학회지
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• 제30권1호
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• pp.14-23
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• 1986

This study was conducted to investigate the correlation between the dissolution rates and the bioavailabilities of commercial phenytoin products, and also the correlation between their biovailabilities in rabbits and those in humans. Dissolution test was conducted in pH 9. 0 alkaline borate buffer (0.2M) using basket method with seven phenytoin products commercially available. According to the dissolution rate, the phenytoin products were divided into three groups, such as rapid, intermediate and slow group. Three phenytoin products from each group were selected for the bioavailability test in rabbits and humans. The bioavailability test was carried out in rabbits and normal volunteers using cross over design. Single doses of 20mg/kg and 300mg/man were orally administered to rabbits and normal volunteers respectively. Average $C_{max}$, $t_{max}$ and AUC of three phenytoin products were determined from the serum concentration-time curve in rabbit and human experiments. The relative bioavailability evaluation was conducted using AUC of three phenytoin products. The correlations between the dissolution rate constants and bioavailabilities (AUC) of three phenytoin products in rabbits as well as those in humans were not found. Whereas, there was significant correlation between average AUC of three phenytoin products in humans and those in rabbits (r=0.993, p<0.1). From the results of this experiment, it can be concluded that the bioavailability of phenytoin products in humans may be predicted from the results of the rabbit experiment. Also it is assumed that the prediction of the bioavailability of phenytoin products in humans may be difficult from the only results of in vitro dissolution test.

• Food Science and Biotechnology
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• 제18권3호
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• pp.712-716
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• 2009

The purpose of this study was to investigate the effect of dietary supplementation of sea tangle (Laminaria japonica) on the blood glucose and lipid metabolism in streptozotocin (STZ)-induced diabetic rats. Male Sprague-Dawley rats were divided into 3 groups fed control, sea tangle powder (15%, w/w), or sea tangle water extract (4%, w/w) diet. Diabetes was induced by a single injection of STZ (60 mg/kg, i.p.) in citrate buffer. The animals were fed each of the experimental diet for 13 weeks. Serum insulin was increased by dietary supplementation of sea tangle in diabetic rats. Dietary sea tangle reduced blood glucose level of diabetic rats compared to the diabetic rats fed control diet. Dietary sea tangle also reduced the serum total cholesterol, low density lipoprotein (LDL)-cholesterol, and triglyceride in the diabetic rats. While hepatic lipids were reduced, fecal excretion of lipids was increased by supplementation with dietary sea tangle in the diabetic rats. These results indicate that dietary sea tangle decreased blood glucose and improved lipid metabolism in STZ-induced diabetic rats and this effect might be exerted by increases in serum insulin and fecal excretion of lipids.

• 한국재료학회지
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• 제13권8호
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• pp.485-490
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• 2003

We have developed a new way of the constant growth technique to maintain a grating height of originally-etched V-groove of submicron gratings up to 1.5 $\mu\textrm{m}$ thickness by a low pressure metalorganic chemical vapor deposition. The constant growth technique is well performed on two kinds of submicron gratings that made by holography and electron (e)-beam lithography GaAs buffer layer grown on thermally deformed submicron gratings has an important role in recovering the deformed grating profile from sinusoidal to V-shaped by reducing mass transport effects. The thermal deformation effect on submicron gratings made by e-beam lithography is less than that on submicron gratings made by holography. The constant growth technique is an important step to realize complex optoelectronic devices such as one-step grown distributed feedback lasers and two-dimensional photonic crystals.

• 한국식품영양과학회지
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• 제24권4호
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• pp.563-569
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• 1995

Myrosinase from Korean cabbage(Bogdoli) was purified and its enzymatic properties were investigated. Myrosinase from the Korean cabbage was purified by DEAE Bio-Gel Sepharose, Concanavalin-A, and Mono-Q column chromatography and exhibited a 55KD molecular weight with a single band on the gel of SDS-PAGE. The enzyme was purified about 21-fold compared to its crude enzyme and a specific activity of purified enzyme was 15, 120units/mg. Optimum pH of the myrosinase was 7.0 in both phosphate and Tris-HCl buffer solutions, the enzyme was stable at pH 6.5~7.0. Optimum temperature of enzyme was 37~38$^{\circ}C$. The enzyme activity was significantly inhibited by Cu2+ and Hg2+, but enhanced by ascorbic acid, resulting in a maximum activity at 1mM ascorbic acid. Among the ascorbic acid analogues, dehydro-ascorbic acid did not affect, whereas others showed a little effect on the enzyme activity, but less than ascorbic acid itself. Reducing agents such as 2-mercaptoethanol and dithiothreitol had no effect on the enzyme activity, but the enzyme activity was enhanced when 2-mercaptoethanol was mixed with ascorbic acid.

• 한국통신학회논문지
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• 제27권10C호
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• pp.937-944
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• 2002

인터넷 트래픽의 급속한 증가로 인해 보다 큰 네크워크 용량이 요구되고 있다. 광 패킷 교환은 상이한 유형의 데이터를 지원하는 미래의 네트워크에서 필요한 특성들인 고속의 데이터 교환, 데이터 속도와 유형에 대한 투명성 등을 제공하여 준다. 본 논문에서는 IP 전송을 위해 광 패킷 코어 스위치와 광섬유링크로 구성된 광 백본 네트워크를 정의한다. 그리고 WDM 광 네트워크에서 광섬유 상에 존재하는 다수의 파장링크의 전 대역을 통합하여 단일매체의 대역으로 관리하는 멀티링크 광 패킷 스위치를 제안한다. 제안된 스위치는 WDM 버퍼를 사용할 뿐만 아니라 출력 링크의 광 패킷 메모리를 균등하게 사용하여, 필요한 메모리의 수를 줄임으로써 광 패킷 메모리를 경제적으로 실현할 수 있다. 컴퓨터 시뮬레이션에 의한 성능평가의 결과는 제안 스위치의 휴효성을 보여준다.