• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.45-53
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• 2009

Die casting process of Mg alloys for high temperature applications was studied to produce an engine oil pan. The aim of this paper is to evaluate die casting processes of the Aluminium oil pan and in parallel to apply new Mg alloy for die casting the oil pan. Temperature distributions of the die and flow pattern of the alloys in cavity were simulated to diecast a new Mg alloy by the flow simulation software. Dies have to be modified according to material characteristics because melting temperature and heat capacity are different. We changed the shape and position of runner, gate, vent hole and overflow by the simulation results. After several trial and error, oil pans of AE44 and MRI153M Mg alloys are produced successfully without defect. Sleeve filling ratio, cavity filling time and shot speed of die casting machine are important parameter to minimize the defect for die casting Magnesium alloy.

• Journal of Microbiology and Biotechnology
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• v.20 no.10
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• pp.1397-1402
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• 2010

Papyriflavonol A (PapA), a prenylated flavonoid [5,7,3',4'-tetrahydroxy-6,5'-di-(${\gamma},{\gamma}$-dimethylallyl)-flavonol], was isolated from the root barks of Broussonetia papyrifera. Our previous study showed that PapA has a broad-spectrum antimicrobial activity against pathogenic bacteria and fungi. In this study, the mode of action of PapA against Candida albicans was investigated to evaluate PapA as an antifungal agent. The minimal inhibitory concentration (MIC) values were 10~25 ${\mu}g/ml$ for C. albicans and Saccharomyces cerevisiae, Gram-negative bacteria (Escherichia coli and Salmonella typhimurium), and Gram-positive bacteria (Staphylococcus epidermidis and Staphylococcus aureus). The kinetics of cell growth inhibition, scanning electron microscopy, and measurement of plasma membrane florescence anisotrophy revealed that the antifungal activity of PapA against C. albicans and S. cerevisiae is mediated by its ability to disrupt the cell membrane integrity. Compared with amphotericin B, a cell-membrane-disrupting polyene antibiotic, the hemolytic toxicity of PapA was negligible. At 10~25 ${\mu}g/ml$ of MIC levels for the tested strains, the hemolysis ratio of human erythrocytes was less than 5%. Our results suggest that PapA could be a therapeutic fungicidal agent having potential as a broad spectrum antimicrobial agent.

• Journal of Ginseng Research
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• v.3 no.1
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• pp.40-53
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• 1979

In order to investigate the optimal conditions which affects to extraction of ginseng extract and saponin in ginseng extract, experiment was carried out varing with ethanol percentage, extraction time, temperature, sol$.$vent and Plant Parts. The results art as follows: 1. The amounts of ginseng saponin was increased according to increanation of ethanol Percentage while the amounts of ginseng extract was decreased. 2. The amounts of ginseng extract was increased as the prolongation of extraction time, on the ether hand, ginseng saponin contents increased lentil 40hr. and decreased after that. 3. By the raise of extract temperature, both of the amounts of ginseng saponin and ginseng extract was increased two times and four times. respectively. 4. The total amounts ginseng extract was obtained 22.86u when the water used as the extraction solvent, 11.28% on ethanol and 11.04U on methanol, in the order. and the saponin contents gained when the extraction solvents of water, methanol and ethanol 7.47%, 12.36% and 12.77%, respectively. 5. It showed 9.23% of ginseng extract in epidermis and 8.4% of ginseng saponin in tail Part of raw ginseng and in the case of dried ginseng, ginseng extract and saponin showed the most amounts in epidermis of 18.28% and 19.35%, respectively. 6. The ratio of panaxadiol and panaxatriol contents of ginseng saponin was almost same when it was extracted varing with ethanol percentage and extraction time (duration), and the more alcohol percentage and the longer extraction time increased, the more fractional content of ginseng saponin was extracted.

• Journal of the Korean Society of Tobacco Science
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• v.23 no.1
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• pp.60-64
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• 2001

The variability of a ventilated filter cigarette depends on the details of its construction and one properties of its components and the variations in filter ventilation is effected by many factors such as tobacco column pressure drop, filter pressure drop, tipping paper and plug wrap permeability, and vent position. In this study, the effects of combination of tipping paper and plug wrap on filter ventilation of cigarettes were studied for the target ventilation level under the specific tobacco column and filter tip in order to reduce the variation of filter ventilation. When Nicolas Baskevitch\`s equation on filter ventilation was used to try out Monte Carlo Simulation, at the combination where tipping paper permeability is high and plug wrap permeability is low, even the small change in tipping paper and plug wrap permeability showed high variation of target ventilation level. Also, according to the analysis data of filter ventilation in cigarettes designed at the level of 45% filter ventilation by the combinations with tipping paper and plug wrap, the variation in cigarette filter ventilation was increased as increasing tipping paper permeability and decreasing plug wrap permeability. As the results of this study, the variation of filter ventilation can be reduced by increasing plug wrap permeability/tipping paper permeability ratio in the cigarette design, considering 2-3% of tipping paper permeability variation(%CV) and about 10% of plugwrap permeability variation.

• Journal of the Korean Society of Safety
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• v.26 no.2
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• pp.32-35
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• 2011

Experimental studies were carried out in an explosion chamber to investigate the influences of multiple cylinder obstacles on local flame propagation. The chamber dimension is 235 mm in height with a $1,000{\times}950\;mm^2$ rectangular cross section and a large vent area of $1,000{\times}320\;mm^2$. Multiple cylinder bars with obstruction ratio of 30% were used. In order to examine the interaction between the propagating flames and the obstacles, temporally resolved flame front images were recorded by a high speed video camera. The propagation behaviour of local flame fronts around the left obstacle was analyzed in terms of two different methods such as the incremental burnt area divided by the flame front length and the average of the local propagation velocity determined at each point along the flame front. It was found that two methods give good consistency.

• Journal of the Korean Society of Safety
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• v.21 no.2 s.74
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• pp.29-34
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• 2006

It is revealed that these are correlated with the height of chamber deciding the turbulence extent. In the first experiment, It was examined about the effects of different multiple obstacles such as circular, triangular and square things with the rig that the dimension of original experimental rig was $700{\times}700{\times}200mm{\wedge}3$. Then the heights of chamber were increased from 200 to 1000mm. The dimensions of each obstacle were $70{\times}700{\times}{\wedge}2$ and rectangular vent area were $210{\times}700{\times}{\wedge}2$. In the second one, we performed to see the effects of locations of different multiple obstacles in 200, 500 and 800mm height from the bottom. The results are : The multiple triangular obstacles caused the highest overpressure while the lowest one was the multiple circle bars. Then, the triangular bars caused the highest flame acceleration while the circular obstacles was lowest too. The results showed that the critical height was 800mm due to the formation of turbulence. And the lesser $Av/V^{2/3}$ were small, the more pressure and pressure acceleration rate were increased.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.54-60
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• 2006

In this paper, we describe a bio-fluidic device for adaptive sample pretreatment, in order to optimize the conditions under which absorbance assays can be conducted. This device can be successfully applied to the measurement of Escherichia coli (E. coli) concentrations using adaptive dilution, with which the dilution ratio can be adjusted during the dilution. Although many attempts have been previously made to miniaturize complex biochemical analyses at the chip scale, very few sample pretreatment processes have actually been miniaturized or automated at this point. Due to the lack of currently available on-chip pretreatments, analytical instruments tend to suffer from a limited range of analysis. This occasionally hinders the direct and quantitative analysis of specific analyses obtained from real samples. In order to overcome these issues, we exploit two novel strategies: dilution with a programmable ratio, and to-and-fro mixing. The bio-fluidic device consists of a rectangular chamber constructed of poly(dimethylsiloxane) (PDMS). This chamber has four openings, an inlet, an outlet, an air control, and an air vent. Each of the dilution cycles is comprised of four steps: detection, liquid drain, buffer injection, and to-and-fro mixing. When using adaptive sample pretreatment, the range in which E. coli concentrations can be measured is broadened, to an optical density (O.D.) range of $0.3{\sim}30$. This device may prove useful in the on-line monitoring of cell concentrations, in both fermenter and aqueous environments.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.67-67
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• 2019

뽕나무과(Moraceae) 닥나무속(Broussonetia)의 품종에 대한 국내 연구동향으로는 잎의 성상이나 암꽃의 포길이, 엽신의 폭과 같은 수목학 분수학적 관점으로 특징을 파악하기 때문에 구분이 어려운 실정이다. 또한 닥나무(Broussonetia kazinoki Siebold)와 꾸지나무[Broussonetia papyrifera (L.) $L^{\prime}H{\acute{e}}r.$ ex Vent.]의 수목학적 특징이 유사하여 오동정의 사례가 발생하기도 한다. 닥나무의 향명은 다양하게 불리지만 그 분류기준은 명확하지 않다. 본 연구에서는 총 4개 마커(ITS, matK, trnL-F, ndhF)의 염기서열 분석과 분자계통학적 분류를 통해 닥나무와 꾸지나무의 교잡종으로 확인된 전라도지역 닥나무 8개체에 대하여 펄프제지 자원으로써의 특성을 확인하였다. 8개체 인피섬유의 형태학적 특징인 섬유장, 섬유폭, 섬유 내강(Lumen)폭을 통해 Runkel ratio, Slenderness ratio, Flexibility coefficient, Rigidity coefficient를 도출하고 종이의 기계적 강도, 내절도와의 상관관계, 섬유와 섬유간의 결합력 등을 예측하였다. 상기와 같은 연구결과는 유전형질이 동일한 전라도지역 닥나무의 형태학적 특성을 통해 펄프제지 공정에 영향을 미칠 수 있는 인자들을 분석 하였다. 이러한 특성에 따라 다양한 품질의 종이를 제조 할 수 있는 기초 자료로 제공될 것이다.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.342-347
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• 2012

This study was conducted to demonstrate the relationship between experience of cannibalism and difference of phenotype in the Korean salamander Hynobius leechii from March to April 2011. We examined whether the different polyphenism of larval salamander is induced as a result of indirect cannibalism in early life cycle. We divided into two groups(one group continuously exposed to the indirect cannibalism and the other group never exposed to the cannibalism). We measured the head width at the level of eyes(HWE), the largest head width(LHW) and snout-vent length(SVL) of the each larva then calculated the ratio of the head size by dividing HWE by LHW. We found that exposure of indirect cannibalism in early life cycle cause the different polyphenism. Our result means the larval salamander responded to the chemical cue from conspecific.

• Journal of the Korean Society of Costume
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• v.63 no.8
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• pp.76-89
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• 2013

This study is about 'asymmetry triangle-Mu' Jeoksam and Hansam in the early days of Joseon Dynasty. A study was done regarding the records of Jeoksam and Hansam in literature, the present state of the excavated 'asymmetry triangle-Mu' clothing Jeoksam and Hansam, and finally a deduction of the reason for the appearance of the 'asymmetry triangle-Mu' clothing Jeoksam and Hansam. The width of front length of 'asymmetry triangle-Mu' clothing in the early days of Joseon Dynasty is 29.5~35 cm and the width of one breath of the sleeve is 29.5~35 cm. The width of 'asymmetry triangle-Mu' is 9.5~16 cm and it is relatively big. Comparing to the width of one breath of the sleeve, it is almost 1:2.2~3.6 ratio. Therefore, when the sleeve was cut, the Mu was linked in order to save fabric the gusset of sleeve had to be folded and turned, and finally it became asymmetric. As a result of the above consideration, since the width of upper garments of $16{\sim}17^{th}$ century was big, the wearing of short tops of Jeoksam or Hansam without side vent as a small 'triangle-Mu' was uncomfortable. Because of this reason, the size had no option but to become bigger. So, during the $16^{th}$ and $17^{th}$ century, a period where mass production of fabric was difficult, the 'asymmetry triangle-Mu' type was considered to be a reasonable cutting method. After the middle of $17^{th}$ century, it can be estimated that 'asymmetry triangle-Mu' clothing disappeared according to the narrow aspect of clothing type.