• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3239-3243
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• 2014

We have developed a simple method for tuning the morphologies of $Cu_2O$ microcrystals. $Cu_2O$ microcrystals were prepared by precipitation at room temperature from a mixture of $Cu(CH_3COO)_2{\cdot}H_2O$, N,N,N',N'-tetramethyl ethylenediamine (TMEDA), ascorbic acid, and polyethylene glycol (PEG). TMEDA was used to promote the formation of copper-TMEDA complexes. A variety of $Cu_2O$ microcrystal morphologies were obtained simply by varying the concentrations of TMEDA and ascorbic acid. Aggregated $Cu_2O$ microspheres are formed at higher concentrations of ascorbic acid in the absence of TMEDA. Aggregated $Cu_2O$ microcubes are formed at lower concentrations of ascorbic acid and higher concentrations of TMEDA. The crystal growth mechanism of these $Cu_2O$ morphologies is explained.

• Archives of Pharmacal Research
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• 제17권4호
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• pp.240-243
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• 1994

Release rates of flurbiprofen from transdermal gels made of poloxamer 407 were evaluated using a membraneless diffusion cell in order to study the effects of formulation variables on flurbiprofen release such as poloxamer 407 (17.5-25%) drug (0.1-1.0%), ethanol (10-20%), PG or PEF 300 (5-15%) concentrations and gel pH(3-7). Isopropyl myristate was employed as a receptor medium for the drug released from the gel. The diffusion coefficient of flurbiprofen decreased linearly as the amount of poloxamer 407 and the drug in the gel increased. The release rate of flurbiprofen was gel increased. The The addition of more ethanol in the gel increased the drug release, resulting from the increase of the thermodynamic activity of the drug in the aqueous phase of the gel. However, the concentration effects of PG and PEG 300 on the release rate of flurbiprofen were negligible over the concentration range used.

• 한국세라믹학회지
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• 제27권4호
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• pp.548-552
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• 1990

Effects of binder addition method during compacting on microstructural change and magnetic characteristics of Sr-ferrite system was investigated. Used binders were PVA and PEG, which were added separately or simultaneously. After compacts were heated at 50$0^{\circ}C$ for 3hr in air for burning out all the binders, they were sintered at 125$0^{\circ}C$ for 2h. Based on results, in the case of using the two binders simultaneously, comparing to single binder system, compacted density was somewhat higher but sintered density was rather lower, and abnormal grain growth was accelerated. According to these sintering characteristics, remanent magnetization and coercive force were also diminished.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권4호
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• pp.241-247
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• 2000

This paper reports on an experimental study of the absorption of COS in a secondary amine diethanolamine. The primary objectives were to investigate an analogy between $N_2$O and COS, thereby allowing an estimation of the physical solubility and diffusivity of the sulfur gases in the reacting amine solutions. The solubilities and diffusivities of $N_2$O and COS in 5~25% aqueous polyethylene glycol at $25^{\circ}C$ were measured. The results appeared to verify the use of an $N_2$O-COS analogy for estimating the solubility and diffusivity of COS in aqueous solutions of alkanolamines up to an approximate 25 weight % concentration. The mean deviation of the $N_2$O analogy relative to the measured solubilities was 3.7%, and the mean deviation between the analogy and the measured diffusion coefficients using the experimental values for Hcos/PEG was 14.6%.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 춘계 총회 및 학술발표회
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• pp.58-58
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• 1994

슬립캐스팅법으로 제조한 튜브형 $\alpha$-알루미나 담체 (평균기공크기 = $0.1 \mum$)에 졸-겔 침지코팅(dipcoating) 또는 가압코팅 (pressurized coating) 법에 의하여 극미세입자 $\gamma$-AlOOH, $TiO_2, SiO_2$, 및 aluminosilicate diphasic 졸을 코팅한 후 300 ~ 500$\circ$C 에서 열처리하여 세라믹 복합막을 제조하였다. 복합막 전체에 대한 균열유무는 $N_2$ 기체투과율의 평균압력에 대한 의존성으로부터 평가하였으며, 한외여과 (ultrafiltration)에의 응용성을 규명하기 위하여 막의 재질 및 제조조건에 따른 polyethylene glycol (PEG) 수용액의 분획분자량 변화를 측정하였다. 합성 세라믹 복합막의 분획분자량 측정 결과 $SiO_2$의 경우 2,000 정도로 매우 우수하였으며 $\gamma-Al_2O_3, TiO_2$, 그리고 aluminosilcate 막들은 6,000 ~ 10,000 범위 값을 갖고 있었다. 또한 막의 기공크기 및 분획분자량을 제어하기 위한 방법으로서 $TiO_2$ 복합막을 300 ~ 700$\circ$C 에서 열처리하였으며 이들에 대한 분획분자량 변화를 비교 분석하였다.

• 한국식물병리학회지
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• 제14권6호
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• pp.714-719
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• 1998

Obligate bacterial parasite attacking Heterodera glycines was firstly found from Chungju soybean field in Korea. Diameters of sporangium and central body were 5.6 ${\mu}{\textrm}{m}$ and 1.9 ${\mu}{\textrm}{m}$ under light microscopy (LM), and 3.9 ${\mu}{\textrm}{m}$ and 1.8 ${\mu}{\textrm}{m}$ under transmission electron microscopy (TEM). Endospore showed cup-shaped with smooth-type exosporium without peg-like thickening in polar area under SEM and TEM. Bacteria completed its life cycle in female of soybean cyst nematode after adhering on cuticle of second-stage juvenile. From these results, the Pasteuria found from Chungju was identified with P. nishizawae.

• 한국재료학회지
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• 제4권2호
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• pp.187-193
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• 1994

무전해 동도금액에서의 각종 안정제, 촉진제등의 첨가제에 따른 영향을 고찰하였다. 욕의 기본성분은 황산구리 10g/1, EDTA-2Na 40g/1, 포르말린 3ml/1, pH조절용 수산화나트륨 용액으로 조성하였고, 안정제, 도금촉진제 및 계면활성제의 첨가에 따른 분극곡선을 검토하여 도금욕의 경향을 검토한뒤 농도변화에 따른 도금속도를 측정하여 최적조건을 구하였다. 안정제는 $\alpha$, $\alpha$'-dipyridy1과 NaSCN을 혼합 사용하는 것이 좋았으며 촉진제로는 pyridine이 계면활성제로는 PEG 4000이 좋았다. 첨가량은 5mg/1이하의 미량이었으며 이후 첨가량이 증가함에 따라 증가함에 따라 도금속도는 직선적으로 감소하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 추계학술대회 논문집
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• pp.327-328
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• 2015

본 연구에서는 전기도금법을 이용하여 수지상(Dendrite) 구리 분말을 제조할 때 첨가제 유무를 비교하였다. 인가전위, 첨가제의 종류(JGB, PEG) 및 농도에 따른 수지상의 형상적인 특성이 비교되었으며, 겉보기 밀도와 비표면적(BET)이 측정되었다. 형상적 특성은 수지상의 2차 가지와 추축의 두께 비(ratio)로 비교한 결과 JGB 첨가(10ppm) 도금욕에서 30.67로 가장 큰값을 가지며, 겉보기 밀도는 JGB 첨가(80ppm)에서 $1.115g/cm^3fh$ 가장 낮은값을 보였다.

• Fibers and Polymers
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• 제7권3호
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• pp.223-228
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• 2006

Hydrogels of semi-interpenetrating polymer networks (semi-IPNs) were prepared by two step reactions. Dimethylaminoethyl methacrylate (DMAM) and poly(ethylene glycol)-dimethacrylate (PEGDM) were copolymerized to yield hydrogels, and then acrylic acid (AA) monomer were adsorbed in the hydrogels followed by polymerization of AA to produce semi-IPNs. The swelling behavior of semi-IPNs depends largely on pH of medium, showing that the degree of swelling of the semi-IPNs exhibits a minimum at pH 6.0. It is observed that the elastic modulus of semi-IPNs is closely related to its swelling behavior.

• Journal of Plant Biology
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• 제23권2호
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• pp.49-54
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• 1980

The optimal conditions for the protoplast isolation from the leaves of pea (Pisum sativum L. cv. Sparkle) and barley (Hordeum vulgare L. cv. Baecdong) were determined in order to achieve a somatic hybridization between two species. It was revealed that the use of 0.5M sorbitol as an osmoticum was appropriate for pea. The yield of intact protoplasts was the highest (40%) when pea leaves were incubated in the enzyme solution for 4 hours. In case of barley, the optimal concentrations of cellulase, pectinase and mannitol as the enzyme solution were 2%, 1% and 0.35M, respectively. And the yield of barley protoplasts was the highest(87%) when leaves were incubated in this enzyme solution for 3.5 hours. A fusion of protoplasts from pea and barley was induced by PEG treatment enriched with calcium salts within 60 minutes.