• Journal of Life Science
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• v.8 no.1
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• pp.32-39
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• 1998

The length and G/C concent of regions of an aphid rDNA unit that spans 13,061bo with 59% G/C content. flolowing belowing below are the those results, 5’ETS is 843bp in length with 69% G/C content, 18S is 2,469bp in length with 59% G/C content, ITS I is 229bp in length with 70% G/C content, 5.8S is 160bp in length with 63% G/C content, ITS II is 325bp in length with 70% G/C content, 28S is 4, 147bp in length with 60% G/C content, IGS is 4,888bp in length with 55% G/C content.

• Korean Chemical Engineering Research
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• v.54 no.1
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• pp.94-100
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• 2016

Hydrogen production via steam reforming of bio-oil from algal biomass over fast pyrolysis with commercial catalysts was carried out. Aqueous bio-oil obtained by phase separation from a crude oil over fast pyrolysis was used as a reactant and comparison studies for activity over different catalysts (FCR-4-02, POS-7, Cat. A, RUA), reaction temperature, and steam/carbon (S/C) ratios were performed. Experimental results showed that different catalytic activities were observed with different S/C ratios and catalyst composition and the highest hydrogen yield of 70% was obtained with a POS-7 catalyst at a S/C ratio of 10 and 1073 K.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1007-1010
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• 2004

본 논문에서는 분산 서비스거부 공격(DDoS)이 발생할 때 네트워크 트래픽의 특성을 분석하기 위해서 트래픽 비율분석법(TRA: Traffic Rate Analysis)을 제안하고 트래픽 비율분석법을 통해서 분석된 다양한 유형의 DDoS 공격의 특성을 기계학습(Machine Learning)을 이용해서 DDoS 공격의 탐지규칙을 생성하고 그 성능을 측정하였다. 트래픽 비율분석법은 감시대상 네트워크 트래픽에서 특정한 유형의 트래픽의 발생비율을 나타내며 TCP flag rate 와 Protocol rate 로 구분된다. 트래픽 비율분석법을 적용한 결과 각각의 DDoS 공격 유형에 따라서 매우 독특한 특성을 가짐을 발견하였다. 그리고, 분석된 데이터를 대상으로 세 개의 기계학습 방법(C4.5, CN2, Na?ve Bayesian Classifier)을 이용해서 DDoS 공격의 탐지규칙을 생성하여 DDoS 공격의 탐지에 적용했다. 실험결과, 본 논문에서 제안된 트래픽 비율분석법과 기계학습을 통한 DDoS 공격의 탐지방법은 매우 높은 수준의 성능을 나타냈다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1015-1021
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• 2010

In this study, the effect of the C/SiC composition ratio on the impact damage of a reaction sintered SiC (RS-SiC) plates was evaluated. An impact test was conducted by using an air gun. The impacter used was a steel ball with a diameter of 2 mm, and the impact velocities were 113, 122, and 180 m/s. The RS-SiC plates were $20\times20\times3$ mm with different C/SiC composition ratios. The ring crack diameters damaged by a steel ball were determined using SEM images. It was observed that the maximum diameter increased with increasing impact velocity, and it rapidly changed with increasing C/SiC composition ratio because of the effect of residual Si and the variation flexural strength. Cone cracks were formed in the case of C/SiC composition ratios of 0.4~0.5, this indicated that the impact damage changed from a ring crack to a cone crack in this critical range of C/SiC composition ratios. The C/SiC composition ratio of 0.3 was determined to be the optimal ratio for the RS-SiC manufacturing process.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.65-75
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• 2017

C-S-H phase is the most abundant reaction product, occupying about 50~60% of cement paste volume. The phase is also responsible for most of engineering properties of cement paste. This is not because it is intrinsically strong or stable, but because it forms a continuous layer that binds together the original cement particles into a cohesive whole. The binding ability of C-S-H phase arises from its nanometer-level structure. In terms of chloride penetration in concrete, C-S-H phase is known to adsorb chloride ions, however, its mechanism is very complicated and still not clear. The purpose of this study is to examine the interaction between chloride ions and C-S-H phase with various Ca/Si ratios and identify the adsorption mechanism. C-S-H phase can absorb chloride ions with 3 steps. In the C-S-H phase with low Ca/Si ratios, momentary physical adsorption could not be expected. Physical adsorption is strongly dependent on electro-kinetic interaction between surface area of C-S-H phase and chloride ions. For C-S-H phase with high Ca/Si ratio, electrical kinetic interaction was strongly activated and the amount of surface complexation increased. However, chemical adsorption could not be activated for C-S-H phase with high Ca/Si ratio. The reason can be explained in such a speculation that chloride ions cannot be penetrated and adsorbed chemically. Thus, the maximum chloride adsorption capacity was obtained from the C-S-H phase with a 1.50 Ca/Si ratio.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1104-1109
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• 2001

Samples with the nominal composition, B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+}$$\delta$/ high $T_{c}$ superconductors containing As as an additive were fabricated by a solid-state reaction method. Samples with Ag of 10wt%, 30 wt% and 50 wt% each were sintered at 86$0^{\circ}C$~875$^{\circ}C$ for 24 hours. The structural characteristics, critical temperature and grain size with respect to Ag contents were analyzed by XRD(X-ray Diffraction) and SEM(Scanning Electron Microscope), respectively. As Ag contents increased, XRD peaks of g in Bi-2223 phase superconductors intensified and the proportion of the phase transition from Bi-2223 to Bi-2212 was increased.increased.

• Korean journal of food and cookery science
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• v.18 no.2
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• pp.193-199
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• 2002

The Job's tear gruels were prepared by various mixing ratios, particle size and soaking times of Job's tear and rice flours, and the physical and sensory properties of these gruel samples were measured by using a Brabender visco-amylograph and sensory evaluation. Also, the changes in the pH and viscosity of the gruel samples stored for 14 days at 4$\^{C}$ were measured as the parameters of gruel quality. The results showed that the peak viscosity was decreased by increasing the ratio of Job's tear flours. The values of peak viscosity and consistency of rice and Job's tear flours increased as the particle size decreased. As the soaking time of rice and Job's tear flours increased, the initial pasting temperature decreased. In sensory characteristics, the nutty taste was increased as the Job's tear flour levels increased. Overall acceptability of Job's tear gruel was the highest in the one of rice and Job's tear flours at 50:50 ratio. During 14 days of storage, the pH and viscosity of Job's tear gruels were increased till the sixth day, and then decreased slightly.

• Korean Chemical Engineering Research
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• v.59 no.2
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• pp.254-259
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• 2021

Optical and electrical characteristics of the fluorocarbon films deposited in a high-density C4F8 plasma under various source powers and pressures were investigated. The F/C ratio of the fluorocarbon film deposited in a high-density C4F8 plasma increased with increasing source power and decreasing pressure due to two-step deposition mechanism. The change in the F/C ratio of the film directly affected the optical and electrical characteristics of the fluorocarbon films deposited in a high-density C4F8 plasma. The refractive index of the fluorocarbon film increased with decreasing source power and increasing pressure contrary to the dependence of the film's F/C ratio on the source power and pressure. This was because the increase in the F/C ratio suppressed electronic polarization and weakened the network structures of the film. The resistivity of the fluorocarbon film showed the same behavior as its F/C ratio. In other words, the resistivity increased with increasing source power and decreasing pressure, resulting from stronger repellence of electrons at higher F/C ratios. This work offers the feasibility of the use of the fluorocarbon films deposited in a high-density C4F8 plasma as an alternative to low dielectric constant materials because the optical and electrical properties of the fluorocarbon film can be directly controlled by its F/C ratio.

• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.530-538
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• 2003

Samples with the nominal composition, B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+}$$\delta$/ (110 K phase) high $T_{C}$ superconductors containing MgO as an additive were fabricated by a solid-state reaction method. Samples with 5~50 wt％ MgO were sintered at 820~86$0^{\circ}C$ for 24 h. The structural characteristics, critical temperature and grain size of the samples with different MgO contents were analyzed by XRD and SEM. As the MgO content increased, the intensity of MgO peaks and ratio of Bi-2212 phase in superconductors were intensified and the proportion of the phase transition from Bi-2223 to Bi-2212 was increased.d.creased.d.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1865-1870
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• 2014

To synthesize ${\omega}$-3 and ${\omega}$-6 balanced polyunsaturated fatty acid (PUFA) oil mixture, flaxseed oil and sesame oil were mixed and their anti-oxidative and sensory characteristics analyzed. For the fatty acid composition analysis results, the ${\omega}$-3 and ${\omega}$-6 PUFA ratios of the F20S80 oil mixture (flaxseed oil 20% and sesame oil 80% oil mixture) and F10S90 (flaxseed oil 10% and sesame oil 90% oil mixture) were represented as 1 to 10 and 1 to 5 ratio for ${\omega}$-3 and ${\omega}$-6 PUFA content from 4.4% to 42.1% and 8.9% to 39.7%, respectively. Since these were within 1:4~1:10 for healthy functional ${\omega}$-3 and ${\omega}$-6 balanced PUFA oil mixtures, these oil mixtures were healthy functional oil mixtures. To analyze anti-oxidative effects, acid values were analyzed. Samples were stored at room temperature, 70% relative humidity (RH) and $45^{\circ}C$, and 70% RH for 16 weeks. The acid value between F10S90 and S100 stored at $45^{\circ}C$ and 70% RH for 16 weeks were not statistically significant. The sensory characteristics such as oxidative odor and sesame odor and taste were not statistically significant among F20S80, F10S90, and sesame S100. Sensory characteristics between F10S90 and S100 stored at $45^{\circ}C$ and 70% RH for 16 weeks were not statistically significant. In conclusion, the sensory and oxidative characteristics of F10S90 were similar to those of S100. Therefore, F10S90 oil mixture should be used as a ${\omega}$-3 and ${\omega}$-6 balanced PUFA healthy functional oil mixture with high anti-oxidative effects.