• 한국세라믹학회지
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• 제35권12호
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• pp.1249-1256
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• 1998

${\beta}$-Silicon carbide(${\beta}$-SiC) whiskers could be synthesized by the carbothermal reduction of kaolin at tem-peratures between 1400 and 1500$^{\circ}C$. The whiskers were grown up to about 1150 of aspect ratio by VS mechanism (showing tapering tips) and to about 45 of that by VLS mechanism (showing round droplet tips) respectively. Hydrocarbon like methane in the reaction atmosphere promoted the formation of gaseous il-icon monoxide(SiO) from silicon dioxide(SiO2) and subsequently reacted with it to form whiskers. The for-mation of ${\beta}$-SiC whiskers increased with increasing carbon content(to 30 wt%) and reaction temperatures. The max. yield of ${\beta}$-SiC whiskers was 15% at 1500$^{\circ}C$ under 20%CH4/80%H2.

• Journal of Advanced Marine Engineering and Technology
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• 제25권4호
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• pp.904-911
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• 2001

The fuels of water-in-oil emulsion have a potential of reducing PM(Particulate Matter) and NOx emissions, and increasing combustion efficiency in the furnaces and the burners. For making the most of the beneficial of the secondary atomization due to the microexplosion, the water droplets distributed in the oil must have the optimal sizes. The purpose of this paper is to investigate the water droplet size distribution characteristics of the different types of the static mixers. For analysis the size distribution characteristics efficiently, image analysis system wes constructed and an appropriate image processing algorithm was developed. Two kinds of static mixers: Kenics type and RF type, were tested. As a results, RF type static mixer shows a better characteristics in the mean drop size, particularly in the condition of high water content.

• 생명과학회지
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• 제25권1호
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• pp.62-67
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• 2015

본 연구는 바위수염 메탄올 추출물이 3T3-L1 지방세포의 분화 및 지방생성의 억제에 미치는 영향을 탐색하고자 하였다. 바위수염 메탄올 추출물의 농도에 따른 3T3-L1 세포의 성장에 미치는 영향을 MTT assay로 분석한 결과 $100{\sim}500{\mu}g/ml$l의 농도에서는 80% 이상의 비슷한 수준의 세포생존율을 보였다. 바위수염 메탄올 추출물을 처리하지 않고 분화를 유도하였을 경우에 세포질 내 지방구의 형성이 활발하게 유발되는 것으로 관찰되었으며, 바위수염 메탄올 추출물에 의한 지방구의 형성이 처리 농도 의존적으로 억제 되는 것을 확인하였다. 또한 바위수염 메탄올 추출물을 100, 300, $500{\mu}g/ml$ 처리한 후의 중성지방의 양은 바위수염 메탄올 추출물을 처리하지 않았을 때보다 35%, 42%, 76%로 농도 의존적으로 억제되는 것을 확인하였다. Insulin, dexamethasone 및 IBMX를 처리하여 분화를 유발하였을 경우 $PPAR{\gamma}$, $C/EBP{\alpha}$ 및 $C/EBP{\beta}$의 발현이 현저하게 증가되었으며, 이러한 분화유도 과정에서 바위수염 추출물을 처리한 결과 $100{\mu}g/ml$의 농도보다 $500{\mu}g/ml$의 처리군에서 $PPAR{\gamma}$, $C/EBP{\alpha}$ 및 $C/EBP{\beta}$의 발현이 단백질 수준에서 감소하였다. 본 연구결과 바위수염 메탄올 추출물은 lipid droplet 및 TG 생성을 감소시킴으로써 지방세포로의 분화를 억제시키는 것으로 나타나, 항비만 식품 소재로서의 개발 가능성이 있는 것으로 사료된다.

• International Journal of Advanced Culture Technology
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• 제8권1호
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• pp.236-242
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• 2020

In this paper, we present the improvement in low moisturizing ability and stability that existing skin softeners have due to the low oil content, by developing skin softener using nanoemulsion of phospholipid liposome, based on the properties of nanoemulsion in cosmetic formulation. In this study, two types of oil; dimethicone (DC 200/6cs) or medium chain triglyceride (MCT), and two kinds of lecithin; unsaturated or saturated were respectively applied to produce nanoemulsion. In the particle size analysis of nanoemulsion, the droplet size of nanoemulsion containing DC200/6cs and unsaturated lecithin was the smallest, and all nanoemulsion showed high stability in the measurement of zeta potential. Therefore, with the smallest particle size and high stability, moisture contents and trans epidermal water loss(TEWL) were measured using the skin softener of DC200/6cs and unsaturated lecithin contained nanoemulsion, and the measurement was compared with the non-oil skin softener and the skin softener with only small amount of oil. The results showed that the moisture content of the skin softener using nanoemulsion increased greatly than other two skin softeners, showing high hydration ability and water retention capacity, and TEWL decreased greatly, therefore preventing the evaporation of moisture from the skin. As a result, the oil content and stability of the skin softener was improved by utilizing nanoemulson based of phospholipid liposome, and it is expected to be used in various ways in cosmetic industry.

• Journal of Pharmaceutical Investigation
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• 제32권4호
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• pp.277-284
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• 2002

Lansoprazole, pharmaceutics for acid-related diseases, is unstable in low pH environments and generally coated with enteric polymer to obtain gastroresistance in stomach. Because its storage stability is influenced by acidic substitutes of enteric polymer, alkaline chemicals wεre generally addεd to dosage form as a stabilizer. In this experience, we coated lansoprazole bead with sodium alginate and evaluated the effect of bead size and sodium alginate coating on the storage stability and dissolution profile of lansoprazole. Sodium alginate solution containing lansoprazole was sprayed as a droplet into 3% (w/v) $CaCl_2$ solution and the resultant bead was coated with starch, sodium alginate, and hydroxypropyl methylcellulose phthalate. The content of lansoprazole granule not coated with sodium alginate decreased to 57.96% of initial content when stored at a severe condition for 4 weeks, but that of lansoprazole granule coated with sodium alginate before enteric coating decreased little and as the thickness of sodium alginate film increased, the content of bead didn't decreased for 4 weeks. Sodium alginate film also improved the gastroresistance without much influencing the maximum dissolution rate.

• Korea-Australia Rheology Journal
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• 제13권4호
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• pp.169-177
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• 2001

Morphological, thermal, rheological, and mechanical properties of reactive compatabilized blends of poly(butylene terephthalate) (PBT) and Polyamide-6 (PA) containing EGMA copolymer were investigated using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), advanced rheometric expansion system (ARES), and universal testing machine (UTM). From the results of thermal analysis by DSC, the melting point of the 30/70 PBT-PA blend was broadened after EGMA was added in the blends, since the enthalpy of melting of the PBT-PA somewhat decreased with the increase of EGMA content. From this result, it is suggested that the EGMA affected to the crystallization behavior and crystallinity of the PBT-PA blends. From SEM micrographs of the 70/30, 50/50, and 30/70 PBT-PA blends, the droplet size of the 30/70 PBT-PA blend was about 0.8 ${\mu}{\textrm}{m}$ which was smaller than that of the 50/50 and 70/30 PBT-PA blends. The complex viscosity of the 30/70 PBT-PA blend observed to be higher than that of the 50/50 and 70/30 PBT-PA blends. From the results of the morphology and rheological properties for the PBT-PA blends, it is suggested that the compatibility is increased in the 30/70 PBT-PA blend than the 50/50 and 70/30 PBT-PA blends. From the results of mechanical properties, it was found that the tensile strength of the 30/70 PBT-PA blend increased with the increase of EGMA up to 2 phr, while tensile strength of the blend in which EGMA content was higher than 2 phr decreased with the increase of EGMA content. From the results of morphological, thermal, rheological, and mechanical properties for the PBT-PA-EGMA blends, it is suggested that the EGMA could be used as a compatibilization role in the blends.

• Metals and materials international
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• 제24권6호
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• pp.1241-1248
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• 2018

The reactive wetting behaviors of molten Zn-Al-Mg alloys on MnO- and amorphous (a-) $SiO_2$-covered steel sheets were investigated by the sessile drop method, as a function of the Al and Mg contents in the alloys. The sessile drop tests were carried out at $460^{\circ}C$ and the variation in the contact angles (${\theta}_c$) of alloys containing 0.2-2.5 wt% Al and 0-3.0 wt% Mg was monitored for 20 s. For all the alloys, the MnO-covered steel substrate exhibited reactive wetting whereas the $a-SiO_2$-covered steel exhibited nonreactive, nonwetting (${\theta}_c>90^{\circ}$) behavior. The MnO layer was rapidly removed by Al and Mg contained in the alloys. The wetting of the MnO-covered steel sheet significantly improved upon increasing the Mg content but decreased upon increasing the Al content, indicating that the surface tension of the alloy droplet is the main factor controlling its wettability. Although the reactions of Al and Mg in molten alloys with the $a-SiO_2$ layer were found to be sluggish, the wettability of Zn-Al-Mg alloys on the $a-SiO_2$ layer improved upon increasing the Al and Mg contents. These results suggest that the wetting of advanced high-strength steel sheets, the surface oxide layer of which consists of a mixture of MnO and $SiO_2$, with Zn-Al-Mg alloys could be most effectively improved by increasing the Mg content of the alloys.

• 한국자원식물학회지
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• 제32권5호
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• pp.415-422
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• 2019

본 연구에서는 Rhodosporidium toruloides를 활용하여 비트 열수추출물의 중성지방 억제효과를 확인하고자 하였다. 대조구, 실험대조구, 비트 열수추출물, 30% 및 60% 에탄올 추출물을 첨가한 YPD 배지에서 배양한 유지효모의 중성지방의 함량은 각각 8.76, 3.43, 2.87, 3.16 및 3.64 mg/dL로 나타났으며, 유지 효모의 세포수는 각각 10.48, 8.46, 12.40, 12.80 및 $8.24{\times}10^3cell/mL$로 나타났다. 대조구, 실험대조구, 0.02, 0.1 및 0.5% 비트 열수추출물을 첨가한 유지효모의 총 지질 함량은 각각 112.29, 38.90, 147.87, 211.36 및 291.89 mg/g로 나타났으며, 유지효모의 중성지방의 함량은 각각 6.02, 2.83, 2.38, 1.37 및 0.73 mg/dL로 나타났다. 대조구, 실험대조구, 0.02, 0.1 및 0.5% 비트 열수추출물의 첨가 농도가 높아짐에 따라서 유지효모내 소량의 형광이 발현됨을 확인하였다. 실험대조구, 0.02, 0.1 및 0.5% 비트 열수추출물을 첨가한 유지효모의 세포수 증가율은 대조구에 비해 각각 -4, 21, 82 및 103%로 증가하였다. 유리지방산과 총 카로티노이드 함량은 비트 열수추출물의 첨가 농도에 따라 농도의존적으로 증가하였다.

• Corrosion Science and Technology
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• 제12권2호
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• pp.85-92
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• 2013

This work is concerned with an evaluation of dynamic boric acid corrosion (BAC) of low alloy steel for reactor pressure vessel of a pressurized water reactor (PWR). Mockup test method was newly established to investigate dynamic BAC of the low alloy steel under various conditions simulating a primary water leakage incident. The average corrosion rate was measured from the weight loss of the low alloy steel specimen, and the maximum corrosion rate was obtained by the surface profilometry after the mockup test. The corrosion rates increased with the rise of the leakage rate of the primary water containing boric acid, and the presence of oxygen dissolved in the primary water also accelerated the corrosion. From the specimen surface analysis, it was found that typical flow-accelerated corrosion and jet-impingement occurred under two-phase fluid of water droplet and steam environment. The maximum corrosion rate was determined as 5.97 mm/year at the leakage rate of 20 cc/min of the primary water with a saturated content of oxygen within the range of experimental condition of this work.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1523_1524
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• 2009

Inkjet technology has various merits as a direct patterning process in plenty of industrial applications, but critical issue such as coffee ring effect should be overcome for the application to an industrial manufacturing process. In this paper, we introduced the morphological analysis of inkjet printed pattrerns on the characristics of inks and substrates. In case of Triethlene Glycol Monoethly Ether based ink, the coffee ring effect was observed. However, an ethanol based ink showed the round shaped morphology under the same printing conditions and surface conditions. An ink consisted of the solvent with high boiling point results in coffee ring effect. This experimental results showed that the morphological change of the printed droplet is caused by the main solvent of ink, rather than the metal content, viscosity and surface tension.