• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.6 s.261
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• pp.547-557
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• 2007

This study was conducted to investigate the flow and combustion characteristic of the experimental burner which was manufactured for the reflection of the oven and broil burner features. As slot shape, spacing between slots, and slot arrangement of the exit area which emits the mixing gas are different in case of oven burners and broil turners, the purpose of this study is to know the affection of the flame interaction and combustion characteristic according to the change of shape factors such as slot shape, slot arrangement, and slot-to-slot spacing. With no relation of the slot shape, as the spacing between slots became narrow, the occurrence of a lift-flame was delayed. So the combustion was possible in the leaner region, but the appearance of yellow-tip became a little fast. Slit slot port had the broadest operating range among the other slot shapes. Specially, from the side of lift-flame, as the jet that spreads downstream in the longitudinal slot was nearly circular just a few slot lengths away from the orifice, slot-to-slot spacing of the Slit port was closer than the other ports. These results could be expected through the computer numerical method and had a good agreement. As the spacing between slots increased, in case of Slit and Mix port, NOx emission rate was constant or decreased, but the NOx emission of Hole port was increased. CO emission rate of Slit and Hole port was increased as the slot-to-slot spacing was broadened.

• Mycobiology
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• v.49 no.1
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• pp.78-85
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• 2021

Morels (Morchella spp.) are valuable medicinal and edible mushrooms. In this study, chemical profiles of aromas and lipophilic extracts of black morel (Morchella importuna) grown in China were analyzed by gas chromatography/mass spectroscopy, along with the evaluation of antioxidant and antimicrobial activities for the lipophilic extracts. Sixty-five compounds in total were identified from the aromas, and 1-octen-3-ol was the main component for aromas of fresh (34.40%) and freeze-dried (68.61%) black morels, while the most abundant compound for the aroma of the oven-dried sample was 2(5H)-furanone (13.95%). From the lipophilic extracts, 29 compounds were identified with linoleic acid as the main compound for fresh (77.37%) and freeze-dried (56.46%) black morels and steroids (92.41%) as the main constituent for an oven-dried sample. All three lipophilic extracts showed moderate antioxidant activities against 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) with the IC50 values ranging 7.56~17.52 mg/mL and 5.75~9.73 mg/mL, respectively, and no obvious antimicrobial activity was observed for lipophilic extracts. The drying methods affect the chemical profile of black morel, and freeze-drying was favorable for retaining nutrients and morel smell. This is the first report on the aroma and lipophilic extracts of M. importuna grown in China.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.1
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• pp.99-99
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• 1993

혈액 및 생체시료 중 필수원소 혹은 독극성 원소의 극미량상분 정밀측정과 동위원소비율측정에 널리 사용되는 유도결합플라즈마 질량분석기(ICP-MS)의 기본원리를 소개하고 ICP-SM를 이용한 혈액중 낮은 ppb수준의 Cd, Hg 그리고 Pb의 정밀분석법을 소개한다. 혈액은 많은 양의 유기물을 포함하고 있으므로 digestion bomb에 질산과 과산화수소를 넣어 microwave oven에서 고온고압 상태로 분해시켜 많은 용액을 얻어 이 용액을 플라즈마에 주입시켜 분석한다. 그리고 수온은 tin(II) chloride 용액을 환원제로하여 생성시킨 수은원소증기를 membrane liquid-gas separator를 이용하여 뽑아내어 플라즈마에 주입시켜 낮은 ppt 수준의 검출한계를 얻는다. 또한 높은 정밀도와 정확도와 극미량 원소 측정에 사용되는 동위원소 회석법율 소개하고 실제 혈액분석에의 응용방법을 제시한다.

• Journal of the Korea Furniture Society
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• v.27 no.4
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• pp.302-308
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• 2016

It has been known that acetylation improves the dimensional stability of wood. Liquid phase acetylation is more popular than gas-phase acetylation for the effectiveness of weight gain of wood. In this study the specimens of domestic red and Korean pines are acetylated in liquid phase and their physical properties, such as density, bending strength, anti-hygroscopicity etc., are analyzed. Acetylation increases the average weights and volume of larch specimens by 11.4% and 3.4%, respectively, and their average oven-dry densities are increased by $0.03g/cm^3$. Acetylation does not influence on Modulus of Rupture (MOR) and Modulus of Elasticity (MOE). The average Percentage Reduction in Hygroscopicity (PRH) and average Percentage Reduction in Water soaking (PRW) of larch specimens are respectively 20.2% and 20.8%. Thus it can be concluded that acetylation improves the dimensional stability of larch specimens.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.111-117
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• 2008

An automation process of filter unit is presented for the application of the assembling procedure and dry furnace work. By that automation procedure, it is expected to enhance working environment such as reducing laboring load, harmful gas, and burning scald. Furthermore, this automation process also minimizes via standardization of manufacturing process so that it may increase productivity and reliability. An automation process of filter unit is presented for the application of the assembling procedure and dry furnace work. Filter automation process also gives a good quality and productivity by simplifying to only one line from the complicated process such as filter cutting$\rightarrow$ adhering$\rightarrow$fabricating in a very small space. It is found that a new conceptual design of dry furnace shows the better quality like uniform heat distribution compared to the conventional design. It is also found that the present design gives a better working environment by adding cooling system.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1997.10a
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• pp.70-77
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• 1997

표면연소버너의 모재 중 최근 많은 관심을 끌고 있는 금속섬유를 이용한 LPG 및 COG의 연소특성을 파악하였다. 연소모드, 매트 표면온도분포, 공해물질 배출량, 버너 전후단 압력 손실을 측정한 결과, COG 연소시가 더 넓은 범위의 적열영역을 얻을 수 있었고, 매트의 평균 표면온도도 높았다. NOx 발생량은 100ppm 이하였고, 연소부하 50kcal/$ extrm{cm}^2$hr에서의 매트 전후단의 압력손실은 30mmH2O로 압력손실은 거의 없었다. 적열범위나 표면온도분포 등이 가스별로 약간의 차이를 보였으나, 매트의 종류에 크게 상관없이 안정연소를 달성할 수 있어 가스 특성이 상이한 각종 가스의 연소에 표면연소기술의 적용이 가능할 것이다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.3
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• pp.145-149
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• 1977

Thermal resistance of dried bacterial spores against dry heat was determined. Spare suspensions of Bacillus subtilis var. niger ATCC 9372, Bacillus stearothermophilus Oxoid Code BR 23 and Clostridium sporogenes ATCC 19404 were located on aluminium strips, dried in electric oven under vacuum at room temperature for 10 minutes. The aluminium strips were laid in the middle of gas flow (hot air and superheated steam) with the velocity of 6 m/sec and heated at $120^{\circ}C$ for 180 seconds. The calculated D-values showed that there were no remarkable differences in the heat resistance of bacterial spares between $R.H.\leqq0.012$ and R. H.=0.51. Furthermore the thermal resistance of B. subtilis spores to dry heat was greater than that of B. stearothermophilus.

• YAKHAK HOEJI
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• v.45 no.5
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• pp.437-441
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• 2001

The quasi-drugs including nonwoven fabric and gauze were sterilized using ethylene oxide (EO) gas. Residual EO in the quasi-drugs was extracted with water (20 mL of water for 1 g of sample) for 24h at 37$^{\circ}C$. Residual EO was determined using GC. The optimal analytical conditions were as follows : column, Carbowax 20M (1.D. 0.2 mm); mobile phase, helium with 30 mL/min; oven temperature 57$^{\circ}C$, injector temperature 18$0^{\circ}C$, detector temperature 20$0^{\circ}C$. The detection limit for EO was 0.10$\mu$g/mL. When the residual EO extracted from nonwoven fabric and gauze was determined, it took more than 9h to get the lower level than 25 ppm which is the limit value of FDA guideline. When the EO residues, ethylene chlorohydrine (ECH) and ethylene glycol (EG) in the 7 commercially available quasi-drugs were determined, no residual EO, ECH, EG were found from the seven commercially available quasi-drugs analyzed by this method.

• Journal of the Korean institute of surface engineering
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• v.27 no.3
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• pp.123-133
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• 1994

Oxidation behavior of STS 304 and 430, produced by POSCO, Korea, was studied in order to study the surface defects formed during manufacturing processes. Oxidation experiments were carried out in a preheat-ed furnace at 850~$1, 250^{\circ}C$ in air and in a simulated coke oven gas(COG) atmosphere. The reaction products were examined by XRD, SEM and EDX on their surfaces and cross sections. Protective $Cr_2O_3$-primary oxide film was formed initially, but at critical point this film was broken and a duplex scale consisting of $Fe_2O_3$- and Fe$Cr_2O_4$- was formed. It was more severely attacked in a simulated COG atmosphere than in air, and STS 304 was superior to STS 430 in oxidation resistance.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.944-951
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• 2011

An improved cholesterol analysis method was developed for powdered infant formula by gas chromatographic separation after liquid-liquid extraction and partition. In the official Korea Food Standard method for cholesterol analysis, the water phase and solvent phase were not well separated in the case of emulsified foods such as powdered infant formulas and baby foods. For the rapid and simple sample preparation method, an optimized direct saponification condition was established for heating temperature, heating time, and KOH concentration. From the results, the optimum conditions were as follows: heating temperature $90^{\circ}C$, heating time 60 min, and 16 M KOH 10 mL for a 2 g infant formula sample; improved separation condition for gas chromatography was as follows: the initial oven condition was $250^{\circ}C$ for 25 min, the oven temperature was increased to $290^{\circ}C$ by $10^{\circ}C$/min ratio, and finally the oven temperature remained at $290^{\circ}C$for 9 min. The developed method could be implemented for the study of cholesterol, providing the advantages of reduced inspection time and cost in emulsified foods such as infant formula.