• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.46-51
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• 2019

Intermittent CSR testing was used to investigate the degradation of a NBR O-ring, and also the prediction of its life-time. An intermittent CSR jig was designed taking into consideration the O-ring's environment under use. Degradation of O-rings by thermal aging was observed between $40^{\circ}C$ and $120^{\circ}C$. O-rings showed non-linear degradation behavior under $80^{\circ}C$. At 20% of failure condition, predicted life-times were 32.5 years by Arrhenius plot and 22.6 years by WLF plot.

• Wind and Structures
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• v.35 no.4
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• pp.269-285
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• 2022

The pressure-mitigating effects of a high-speed train passing through a tunnel with a partially reduced cross-section are investigated via the numerical approach. A compressible, three-dimensional RNG k-ε turbulence model and a hybrid mesh strategy are adopted to reproduce that event, which is validated by the moving model test. Three step-like tunnel forms and two additional transitions at the tunnel junction are proposed and their aerodynamic performance is compared and scrutinized with a constant cross-sectional tunnel as the benchmark. The results show that the tunnel step is unrelated to the pressure mitigation effects since the case of a double-step tunnel has no advantage in comparison to a single-step tunnel, but the excavated volume is an essential matter. The pressure peaks are reduced at different levels along with the increase of the excavated earth volume and the peaks are either fitted with power or logarithmic function relationships. In addition, the Arc and Oblique-transitions have very limited gaps, and their pressure curves are identical to each other, whereas the Rec-transition leads to relatively lower pressure peaks in C_Pmax, C_Pmin, and ΔC_P, with 5.2%, 4.0%, and 4.1% relieved compared with Oblique-transition. This study could provide guidance for the design of the novel railway tunnel.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.20-20
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• 2020

신곡수중보는 한강종합개발사업(1982년~1986년) 중 하도정비로 인하여 상시 수위가 저하됨으로써 조수의 과도한 역류 등으로 발생하는 이수상의 문제점을 해결하고 상류에 설치된 잠실수중 보 사이의 수위유지 및 하천 공간 이용의 극대화, 연안 농경지의 용수공급 및 하천환경 보전을 목적으로 건설되어, 「잠실 및 신곡수중보 관리규정(1986)」 및 「신곡수중보 운영 매뉴얼」에 의해 관리·운영되고 있다. 신곡수중보는 준공된 이래로 한강하류의 흐름 해석에 있어 중요한 기준과 경계로서 이와 관련한 다양한 연구가 진행되었다. 신곡수중보로 인한 흐름의 변화가 하상과 생태에 미치는 영향에 관한 연구와 하구역에서의 조위 및 흐름특성과 밀도류의 거동에 관한 1, 2차원 수치해석연구가 활발히 진행되었다. 본 연구에서는 그동안 1, 2차원 수치해석연구로 한정되었던 신곡수중보 흐름특성에 관련하여 실제 수문 운영 방식을 반영한 3차원 수치해석을 수행하여 구조물의 상·하류에서 발생하는 와류 및 이차류와 같은 3차원적 흐름 구조와 이에 따른 지형의 침식·퇴적 및 구조물에 미치는 영향 등을 구체적으로 분석하였다. 우선, 신곡수중보 운영 매뉴얼과 실제 가동보 운영시스템을 비교하여 수문개방 시기, 유량 기준의 수문 운영 방법, 수위 변화에 따른 수문 운영 방법, 수문개방 순서를 분석하고 신곡수중보 주변 흐름에 대한 3차원 수치해석모형 구축을 위한 경계조건을 산정하였다. 수치해석에는 상용프로그램인 FLOW-3D를 사용하였으며, 경계처리기법 및 난류해석을 위해 FAVOR 기법과 RNG k-ε 모델을 적용하였다. 수문 동시개방 개수, 수문 개방 위치 및 순서, 개방 높이에 대한 조건을 변화시켜 구성한 시나리오에 대해 수치해석 후, 유속, 난류에너지, 이차류 등의 흐름특성을 분석하고 상·하류 수위차에 따른 방류량을 산정하여 시설물의 관리안을 도출하고 운영 매뉴얼의 개정안을 제시하였다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.3
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• pp.365-378
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• 2024

The operating system (OS) of mobiles or embedded devices is based on the Linux kernel. These OSs request random numbers from the Linux kernel for system operation, such as encryption keys and security features. To provide random numbers reliably, the Linux kernel has a dedicated random number generator (Linux Pseudo Random Number Generator, LPRNG). Recently, LPRNG has undergone a major structural changes. However, despite the major changes, no security analysis has been published on the structure of the new LPRNG. Therefore, we analyze these structural changes as a preliminary study to utilize the security analysis of the new LPRNG. Furthermore, the differences between before and after the changes are divided into cryptographic and performance perspectives to identify elements that require security analysis. This result will help us understand the new LPRNG and serve as a base for security analysis.

• KSBB Journal
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• v.11 no.2
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• pp.238-245
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• 1996

Microbial desulfurization characterlstics of a bituminous coal have been determined by using Thiobacillus ferrooxidans. The effects of process variables (such as coal pulp density, particle size and addition of surfactants) on pyrite removal have been investigated in both shake and airlift-bioreactor culture experiments. In shake experiments, pyrite could be removed over 78% for pulp densifies below 20% (w/v) and removed below 40% for pulp densities over 30% (w/v) in 8 days. Pyrite removal decreased with increasing pulp densities, and it also decreased sharply with increasing particle sizes. In airlift bioreactor experiments, pyrite at 50% (w/v) pulp density could be removed about 50%. Its value is much higher than 15% at the same pulp density in a shake experiment. With addition of surfactants, pyrite removal was enhanced in shake experiments significantly, whereas it was slightly decreased in an airlift bioreactor experiment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.209-214
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• 2006

One hundred Individuals that were collected from plains and mountains all around South Korea were used for this experiment. The inhibition abilities of lipid peroxidation by Artemisia spp. collections were compared with BHT (butylated hydroxytoluene). The results could be confirmed the excellency fur control of lipid peroxide level such as BHT 200 ppm in all mugwort collections. Antioxidant activity (AEAC), electron donating ability (EDA), total phenolic compound, and flavonoids of 100 Artemisia spp. collections were analyzed. Total phenolic compound contents of Artemisia spp. collections were ranged from 156 to 1,767 rng/100 g, and mugwort collections with more than 900 mg/100 g of total phenolic compound content were 20 individuals. Electron donating abilities were ranged from 13.4 to 95.0%, and mugwort collections over 90% of electron donating ability were 23 individuals. Antioxidant activity of ethanol extracts that used ABTS and DPPH radical were measured and mugwort collections with high total phenolic compound contents had high radical exclusion ability as well. Artemisia spp. collections, AC-60, AC-67, AC-77, that showed the high levels of antioxidant activities and had good growth characters and productivity, were selected for mass production.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.5
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• pp.570-575
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• 2001

Three feeding experiments were conducted to investigate the effects of herbs (Obosan-C or Obosan-O) as an additive in formulated diets on growth and body composition of juvenile abalone (Haliotis discus hannai), Three replicate groups of abalone initially average weighing 206 mg, 827 mg and 432 mg were fed the each one of experimental diet containing $0\%\;or\;1\%$ Obosan for 10 (experiment 1), 7 (experiment 2) and 19 weeks (experiment 3), respectively. In addition, an imported commercial diet for abalone was also employed to compare growth performance of juvenile abalone. Weight gain of abalone fed the diet containing Obosan-O was significantly (P<0.05) higher than that of abalone fed the control diet in the experiment 3. Moisture, crude protein and ash contents of soft whole body were not influenced by dietary herbs (P>0.05), whereas crude lipid content of abalone fed the diets containing Obosan-C was significantly (P<0.05) lower than that of abalone fed the control diet in the experiment 2. The results indicate that Obosan-O as an additive in formulated diet can improve body growth of juvenile abalone.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1423-1436
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• 2010

The effects of meteorological and reclaiming conditions on the reduction of suspended particles are investigated using a computational fluid dynamics (CFD) model with the k-$\varepsilon$ turbulence closure scheme based on the renormalization group (RNG) theory. Twelve numerical experiments with different meteorological and reclaiming conditions are performed. For identifying the meteorological characteristics of the target area and providing the inflow conditions of the CFD model, the observed data from the automatic weather station (AWS) near the target area is analyzed. Complicated flow patterns such as flow distortion, horse-shoe vortex, recirculation zone, and channeling flow appeared due to the topography and buildings in the domain. Specially, the flow characteristics around the reclamation area are affected by the reclaiming height, reclaiming size and windbreak height. Reclaiming height affected the wind speed above the reclaiming area. Windbreak induces more complicated flow patterns around the reclaiming area as well as within the reclaiming area. In front of the windbreak, flow is distorted as it impinges on the windbreak. As a result, upward flow is generated there. Behind the windbreak, a secondary circulation, so called, a recirculation zone is generated and flow is reattached at the end of the recirculation zone (reattachment point). At the lower part of the recirculation zone, there is a reverse flow toward the windbreak. Flow passing to the reattachment point starts to be recovered. Total amounts of suspended particles are calculated using the frictional and threshold frictional velocities, erosion potential function, and the number of surface disturbance. In the case of a 10 m-reclaiming and northerly wind, the amount of suspended particles is largest. In the presence of 5 m windbreak, the friction velocity above the reclaiming area is largely reduced. As a result, the total amount of the suspended particles largely decreases, compared to the case with the same reclaiming and meteorological conditions except for the windbreak The calculated suspended particle amounts are used as the emission rate of the dispersion model simulations and the dispersion characteristics of the suspended particles are analyzed.

• Journal of Animal Science and Technology
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• v.47 no.2
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• pp.305-316
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• 2005

This study was conducted to determine the total amount and type of seleniwn (Se) in the Se-enriched mushroom and its spent mushroom composts (SMC), and to investigate the metabolism in relation to Se accwnulation in the mushroom. Mushrooms, Flammulina velutipes, used in this study were grown for 60 days by adding 2 rng of inorganic Se (Na2Se03) per kg of mushroom composts (MC) on as-fed basis and were compared with normal mushrooms grown on the non Se-supplemented Me. Total Se contents for Se-treated mushrooms were significantly increased (P < 0.0001) by 20-fold (4.51 $\mu$/ g of dry) compared to Se-untreated (0.23 $\mu$/ g of dry). On the contrary, organic Se ratio was significantly lower (P < 0.0001) in the Se-treated mushroom (72.3 %) than the Se-untreated one (100 %, not analytically detected of inorganic Se). Se distribution upon a length in the Se-treated mushrooms was the highest in the bottom part (6.86 $\mu$/ g of dry) near to MC, and top and middle parts were significantly lower (3.71 and 3.01 $\mu$/ g of dry, respectively; P < 0.001) than the bottom. In the SMC from Se-treated mushrooms, the significant amount of Se (5.04l1g/g of dry) was remained, but that from the Se-untreated mushrooms was significantly low (P$\mu$ / g of dry. Se-treated SMC showed a high ratio of organic Se (65.67 %), suggesting that the significant amount of inorganic Se in the SMC was converted to organic Se by mushroom mycelia. Prior to mycelia inoculation in the mushroom culture, the sterilization of MC brought approximately 18% of Se loss in the MC. Apparent and net accumulation rates (%) for Se into mushrooms were 14.81 and 10.14 %, respectively, resulting from the Se volatilization into the air via metabolic process of mushroom itself. The result of this study shows that inorganic Se addition to MC for mushroom improved the organic Se contents in the mushroom and SMC. This study showed the possibility that Se in Se-enriched mushroom and SMC could be utilized as Se sources of food for human as well as feed for livestock.

• THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
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• v.2 no.1
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• pp.113-160
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• 1996

Cancer is one of the most important cause of death. So recently, investigation of cancer progress prosperously all over the world. Cancer in the present medicine correspond to You-Am, Sin-Am, Young-Soon, Sel-Gyun, Sil-Young, Young-Lyoo, Seg-Je, Seg-Young, Seg-Ha, Jerk-Chui(積聚), Jing-Ha, Oel-Gyek, Ban-Oui, Bi-Gi, Bok-Lyang, Jang-Dan, Hyen-Bek in the oriental medicine. Among these, generally Jerk-Chui(積聚) is expressed to cancer. So to develop of new drugs of cancer in the present medicine, bibliographic investigation of mass-prescriptions was studied in the oriental medicine-books. According to the bibliographic study of Jerk-Chui-prescriptions, the results run as follows. 1. According to the analyses of three hundred sixty eight Jerk-Chui-prescriptions in the twenty-seven kinds of literature, the frequency number of the used drugs were Pericarpium Citri Nobilis Viride 140 times, Pericarpium Citri Reticulatae 135 times, Rhizoma Scirpi 124 times, Radix Aucklandie 115 times, Rhizoma Zedoariae 114 times, Cortex Magnoliae Officinalis 111 times, Radix Glycyrrhizae 106 times, Rhizoma Zingiberis 100 times, Rhizoma Coptidis 94 times, Radix Ginseng 93 times, Poria 86 times, Rhizoma Pinelliae 85 times, Semen Arecae 83 times, Rhizoma Cyperi 82 times, Radix Angelicae Sinensis 80 times, Rhizoma Atractylodis 74 times, Massa Fermentata Medisinalis 67 times, Radix Et Rhizoma Rhei 66 times, Fructus Aurantii 62 times, Fructus Hordei Genninatus 55 times, Conex Cinnamomi 54 times, Fructus Evodiae 51 times, Fructus Aurantii Immaturus 49 times, Fructus Crataegi 49 times, Rhizoma Cnidii 46 times, Radix Platycodi 44 times, Semen Tiglii 44 times, Radix Aconiti 43 times, Fructus Amoni 38 times, Semen Raphani 37 times, Radix Aconiti Praeparata 36 times, Radix Scutellariae 35 times, Pericarpium Zanthoxyli 35 times, Rhizoma Corydalis 33 times, Rhizoma Acori Graminei 31 times, Carapax Amydae 31 times, Fructus Foeniculi 31 times, Semen Persicae 30 times, Radix Bupleuri 30 times. 2. The frequency number of the most imponant used drugs in the Jerk-Chui-prescriptions were Rhizoma Coplidis 41 times, Rhizoma Scirpi 35 times, Radix Et Rhizoma Rhei 31 times, Pericarpium Citri Reticuiatae 30 times, Rhizoma Zedoariae 27 times, Rhizoma Cyperi 22 times, Cortex Magnoliae Officinalis 22 times, Rhizoma Atraclylodis 22 times, Pericarpium Citri Nobilis Viride 21 times, Rhizoma Pinelliae 20 times, Semen Arecae 20 times, Fructus Crataegi 18 times, Rhizoma Zingiberis 17 times, Carapax Amydae 16 times, Semen Pharbitidis 13 times, Poria 12 times, Radix Angelicae Sinensis 10 times, Semen Persicae 10 times, Fructus Evodiae 10 times, Radix Aeoniti 10 times, Radix Glycyrrhizae 9 times, Massa Fennenlata Medisinalis 9 times, Fructus Aurantii 9 times, Fructus Hordei Genninatus 8 times, Radix Aueklandie 8 times, Rhizoma Atractylodis 8 times, Radix Bupleuri 8 times, Radix Ginseng 7 times, Semen Raphani 7 times, Radix Astragali 7 times, Cortex Cinnamomi 6 times, Fructus Aurantii Immaturus 6 times, Rhizoma Cnidii 6 times, Radix Aconiti Praeparata 5 times, Fructus Foeniculi 5 times, Lacca Sinica Exsiccata 5 times, Radix Aconiti 5 times, Rhizoma Zingiberis 5 times. 3. The clinical-botanic classifications of the used drugs in the Jerk-Chui-prescriptions were regulating the flow of Qi drugs, warm-heating drugs, promoting blood circulation drugs, killing mass drugs, resolving drugs, purgative drugs, Qi and blood tonics drugs, heat clearing drugs, removing dampness by promoting diures is drugs, phlegm eliminating drugs, allaying pain drugs. 4. According to the nature and taste in the drugs, warm and heating recipes were used most, heatclearing recipes were used a few times assistantly. 5. The Jerk-Chui-prescription used frequently was Bun-Don-Tang, which was used 13 times ; Bok-Oyang-Hoan 12 times, Bi-Gi-Hoan(肥氣丸) 12 times, Sik-Boon-Hoan 12 times, A-Uie-Hoan 12 times, Bi-Gi-Hoan 12 times, Dai-Cil-Gi-Tang 8 times, San-Cuie-Tang 8 times, Guye-Gyen-Tang 6 times, On-Baig-Won 5 times, So-Jek-Jeng-Ouen-San 5 times, Jin-In-Hoa-Cel-Tang 5 times, Byel-Gab-San 5 times, Sng-Hong-Hoan 5 times, Ji-Sil-San 4 times, So-A-Oie-Hoan 4 times, Hyang-Rng-Hoan 4 times.