• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1052-1057
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• 2004

A small-scale loop heat pipe with polypropylene wick was fabricated and tested for its thermal performance. The container and tubing of the system was made of stainless steel and several working fluids were used to see the difference in performance including methanol, ethanol, acetone, R134a, and water. The heating area was 35 mm ${\times}$ 35 mm and there were nine axial grooves in the evaporator to provide a vapor passage. The pore size of the polypropylene wick inside the evaporator was varied from 0.5 m to 25 m. The size of condenser was 40 mm (W) ${\times}$ 50 mm (L) in which ten coolant paths were provided. The inner diameter of liquid and vapor transport lines were 2.0 mm and 4.0 mm, respectively and the length of which were 0.5 m. The PP wick LHP was operated with methanol, acetone, and ethanol normally. R134a was not compatible with PP wick and water was unsuitable within operating limit of $100^{\circ}C$. The minimum thermal load of 10 W (0.8 W/cm2) and maximum thermal load of 80 W (6.5 W/cm2) were achieved using methanol as working fluid with the condenser temperature of $20^{\circ}C$ with horizontal position.

• 한국재료학회지
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• 제21권8호
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• pp.468-475
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• 2011

[ $LaMeO_3$ ](Me = Cr, Co) powders were prepared using the polymeric precursor method. The effects of the chelating agent and the polymeric additive on the synthesis of the $LaMeO_3$ perovskite were studied. The samples were synthesized using ethylene glycol (EG) as the solvent, acetyl acetone (AcAc) as the chelating agent, and polyvinylpyrrolidone (PVP) as the polymer additive. The thermal decomposition behavior of the precursor powder was characterized using a thermal analysis (TG-DTA). The crystallization and particle sizes of the $LaMeO_3$ powders were investigated via powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and particle size analyzer, respectively. The as-prepared precursor primarily has $LaMeO_3$ at the optimum condition, i.e. for a molar ratio of both metal-source (a : a) : EG (80a : 80a) : AcAc (8a) inclusive of 1 wt% PVP. When the as-prepared precursor was calcined at $700^{\circ}C$, only a single phase was observed to correspond with the orthorhombic structure of $LaCrO_3$ and the rhombohedral structure of $LaCoO_3$. A solid-electrolyte impedance-metric sensor device composed of $Li_{1.5}Al_{0.5}Ti_{1.5}(PO_4)_3$ as a transducer and $LaMeO_3$ as a receptor has been systematically investigated for the detection of NOx in the range of 20 to 250 ppm at $400^{\circ}C$. The sensor responses were able to divide the component between resistance and capacitance. The impedance-metric sensor for the NO showed higher sensitivity compared with $NO_2$. The responses of the impedance-metric sensor device showed dependence on each value of the NOx concentration.

• 분석과학
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• 제15권3호
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• pp.300-316
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• 2002

수질 및 토양 시료 중의 PBBs의 분석방법 확립을 위해 표준물질이 준비된 PBBs 22종을 대상으로 추출 및 정제 등의 전처리 회수율 및 검출한계를 환경시료로부터 얻었다. PBBs의 시료 추출법으로 액/액, 속실렛, 초음파 추출법을 적용하였고, 실리카겔, 플로리실 정제컬럼의 적용성 검토 후 GC/MS로 분석하였다. 수질 시료의 경우 검출한계는 브롬화된 정도에 따라 약간의 차이를 보였고 5~10 ng/L이었으며, n-hexane, dichloromethane 및 toluene 등의 단일 용매의 평균회수율은 96~107%, n-hexane:acetone (1:1) 및 (9:1)의 혼합용매의 평균 회수율은 60~80%로 나타났다. 또한, 토양 시료의 경우 검출한계는 0.5~3.5 ng/g이었으며, 선정 용매의 평균 회수율은 속실렛 추출이 67~97% 및 초음파 추출이 64~76%로 나타났다.

• 한국자기학회지
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• 제16권1호
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• pp.107-110
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• 2006

Emulsification-diffusion법에 의해 magnetite를 생분해성 고분자인 PLCA로 캡슐화 시켜 magnetite/PLGA 복합분말을 제조하였다. 이때 유기용매의 종류 변화가 얻어진 복합분말의 크기에 미치는 영향을 살펴보기 위해 다양한 종류의 유기용매[ethyl acetate(EA), propylene carbonate(PC), acetone (ACE)]가 사용되었으며, 분말의 입도분포는 동적 광산란법에 의해 측정되었다. 물에 부분적으로 용해되는 용매인 EA나 PC가 사용되었을 경우에는 80nm이하의 작은 크기의 복합분말이 얻어진 반면, 물에 잘 용해되는 용매인 ACE가 사용되었을 경우에는 330nm 이상의 큰 복합분말이 얻어졌다.

• 한국식품과학회지
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• 제32권6호
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• pp.1234-1243
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• 2000

Polystyrene 재질 용기 내에 함유된 내분비계 장애추정물질인 styrene dimer 및 trimer의 분석 방법과 컵라면 및 요구르트 용기로부터 식품으로 이행된 량을 정량하는 방법을 연구하였다. 재질 중 styrene dimer와 trimer의 함량은 재질을 tetrahydrofuran에 완전히 용해시킨 후, n-hexane을 이용하여 고분자량체 만을 석출시켜 제거함으로써 효과적으로 분석할 수 있었다. 식품분석은 GC/MS SIM-mode를 이용함으로써 $3.2{\sim}87\;ppb$ 수준의 미량 분석이 가능하였다. 라면시료 중의 지방제거 과정으로는 flrorisil 방법만에서 80% 정도의 높은 회수율을 나타내었고, hexane 포화 acetonitrile 분배 과정을 거치면서 상당히 감소하였다. 그러나 요구르트의 경우, 전처리 과정 없이 추출 후 곧바로 분석이 가능하였다. 추출 용매로는 라면에 대하여는 acetone/hexane(1:1)용액이 80% 정도의 가장 높은 회수율을 보였으며, 요구르트에 대하여는 aceton/hexane(1:1)뿐만 아니라, dichloromethane, ether등에서 비슷한 회수율이 얻어졌다.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1393-1400
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• 2009

A bacteriocin-producing strain PI80 was isolated from the gut of Penaeus indicus (Indian white shrimp) and identified as Streptococcus phocae PI80. The bacteriocin was purified from a culture supernatant to homogeneity as confirmed by Tricine SDS-PAGE. Reverse-phase HPLC analysis revealed a single active fraction eluted at 12.94 min, and MALDI-TOF mass spectrometry analysis showed the molecular mass to be 9.244 kDa. This molecular mass does not correspond to previously described streptococcal bacteriocins. The purified bacteriocin was named phocaecin PI80 from its producer strain, as this is the first report of bacteriocin production by Streptococcus phocae. The bacteriocin exhibited a broad spectrum of activity and inhibited important pathogens: Listeria monocytogenes, Vibrio parahaemolyticus, and V. fischeri. The antibacterial substance was also sensitive to proteolytic enzymes: trypsin, protease, pepsin, and chymotrypsin, yet insensitive to catalase, peroxidase, and diastase, confirming that the inhibition was due to a proteinaceous molecule (i.e., the bacteriocin), and not due to hydrogen peroxide or diacetyl. Phocaecin PI80 moderately tolerated heat treatment (up to $70^{\circ}C$ for 10 min) and resisted certain solvents (acetone, ethanol, and butanol). A massive leakage of $K^+$ ions from E. coli $DH5\alpha$, L. monocytogenes, and V. parahaemolyticus was induced by phocaecin PI80, as measured by Inductively Coupled Plasma Optical Emission Spectrometry (ICPOES). Therefore, the results of this study show that phocaecin PI80 may be a useful tool for inhibiting L. monocytogenes in seafood products that do not usually undergo adequate heat treatment, whereas the cells of Streptococcus phocae PI80 could be used to control vibriosis in shrimp farming.

• 동아시아식생활학회지
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• 제14권2호
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• pp.156-160
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• 2004

This study was carried out to examine the changes of chlorophyll a and b contents by the extraction temperatures and the number of soaking using five kinds of Korean green teas(3 kinds of green tea and 2 kinds of tea bag) which were obtained from a local market in Daegu city, Korea. The chlorophylls were extracted with 80% acetone, and determined by a visible spectrophotometer. The concentration of chlorophyll in Sulrok(tea bag) were the highest among all kinds of teas when they were extracted at 60, and decreased with the number of soaking increased. On the other hand, the chlorophyll content of green teas was the highest at 80, and decreased with the increase of the number of soaking as the tea bag did. It was found that the Korean tea bag contained more chlorophyll than green teas did, and green teas contained significantly more chlorophyll b than chlorophyll a.

• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.106-110
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• 1996

Bromelain(EC 3.4.22.4), the collective name for the proteolytic enzymes found in tissues of the plant family Bromeliaceae(pineapple), has been used as a tenderizing agent in food processing, and as an antiinflammatory agent in pharmaceuticals. In this paper, we describe the simple purification method of bromelain using Korean pineapple fruit. After removing contaminants at 30% saturation of ammonium sulfate, the supernatant obtained was treated again with ammonium sulfate to 80% saturation. Wit the above salt fractionation, partially purified bromelain could be obtained. To get highly purified bromelain, the previous 30% to 80% ammonium sulfate treated precipitate was dialyzed against 25mM sodium acetate buffer(pH 5.0) followed by passing through a CM- cellulose cation exchange column. Fruit bromelain was eluted as a major peak at 0.5~0.8M NaCI gradient. The present method is simpler with high wield than the traditional purification method-acetone treatment and several consecutive chromatographic processes.

• 공업화학
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• 제9권1호
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• pp.76-81
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• 1998

초임계 $CO_2$중에 미량 희석된 아세톤의 실리카겔(SG800, 세공경 80nm, 입자경 $10{\mu}m$)표면에서의 물리적인 흡착현상을 FTIR 측정기법에 의해 측정하여, 그 결과를 크로마토그래피 측정기법을 이용해 얻어진 흡착현상과 비교하였다. 크로마토 측정기법에 의해 얻어진 흡착등온선(온도 313K, 압력 1MPa~15MPa)은 $CO_2$의 임계압력(7.28MPa) 보다 낮은 압력에서 최대값을 가지며, 압력이 증가함에 따라 감소하는 경향을 보여준다. 이 결과는 아세톤과의 수소결합 형성에 의해 적색변위(red-shift, 흡착피크가 낮은 파수 영역으로 이동하는 현상)한 실리카겔 표면 OH기의 IA(Integral Absorbance, 적분강도)의 압력의존성과 정성적으로 일치한다. 그러나 초임계유체 영역에서의 크로마토 측정기법에 의한 흡착등온선의 압력증가에 따른 감소비가 FTIR 측정기법에 의한 IA 곡선의 압력증가에 따른 감소비에 비해 조금 크게 감소하는 경향을 보여준다. 이 결과는 비교적 약한 상호작용을 가지는 van der Waals 결합력과 상대적으로 강한 흡착력을 가지는 수소결합력이 실리카겔 표면에서의 아세톤의 흡착에 동시에 영향을 미치고 있다는 것을 나타낸다. 초임계 $CO_2$와 $N_2$가스중에 미량 희석된 트리에틸아민의 FTIR 실험결과로부터 실리카겔 표면에 흡착된 아민류 유기용매의 독특한 분광학적 흡착특성, 흡착띠(band)가 $1300cm^{-1}$ 부근까지 적색변위하는 특성을 발견할 수 있었다.

• 한국수산과학회지
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• 제46권2호
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• pp.119-128
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• 2013

A protease inhibitor was fractionated from fish eggs using methods based on protein solubility. Fractionation efficiency was evaluated with regard to percent recovery and total inhibitory activity (U). The fractionation of protease inhibitor (PI) from egg extracts of skipjack tuna (ST, Katsuwonus pelamis), yellowfin tuna (YT, Thunnus albacores), and Alaska pollock (AP, Theragra chalcogramma) was performed by precipitation with cold acetone or ammonium sulfate (AS). Fractions exhibiting the strongest inhibitory activity contained 20-40% (v/v) cold acetone or 40-60% saturated AS fractions. AS fractionation was more effective in isolating PI than was precipitation with acetone. The total inhibitory activity and percent recovery of fraction obtained with AS 40-60% toward trypsin and $N{\alpha}$-benzoyl-L-arginine-p-nitroanilide (BAPNA) were 4,976 U and 24.2% for ST, 3,331 U and 38.1% for YT, and 4,750 U and 43.8% for AP, respectively. In comparisons against six commercial proteases, 40-80% AS fractions, made by combining the 40-60% and 60-80% AS fractions from fish egg extract, exhibited the strongest inhibition of trypsin when using a casein substrate. These results suggest that fish eggs act as serine protease inhibitors and may be useful for protease inhibition in foodstuffs.