• 한국식품과학회지
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• 제36권1호
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• pp.19-24
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• 2004

5% corn oil과 17 mM Brij 700으로 제조한 corn oil-in-water emulsion(O/W)의 droplet의 크기는 첨가되는 phenol의 양이 많아질수록 지방구가 다소 커지는 경향을 보였으며, continuous phase의 surfactant 양은 대조구에 비해 다소 낮아졌다. O/W에 녹차로부터 분리한 phenol류를 100-200 ppm의 농도로 첨가하고 30일간 저장하며 hydroperoxide의 생성량을 측정한 결과 대조구에 비해 낮은 hydroperoxide 함량을 보여 유도기간이 길어지는 것으로 나타났으며, phenol 종류별 hydroperoxide 생성억제 효과는 BHT > procyanidin B3-3-O-gallate>(+)-gallocatechin>(+)-catechin의 순서로 나타났다. 지방 산화의 결과 발생하는 aldehyde의 함량을 측정함으로서 산화정도를 측정하기 위하여 headspace hexanal 양을 측정한 결과, 대조구는 15일까지 hexanal이 검출되지 않았으나 phenol 첨가구는 20-30일로 headspace aldehyde의 불검출기간이 길어졌으며, 농도가 증가할수록 낮은 함량을 나타내었다. Phenol 종류별 headspacealdehyde 생성 억제 효과는 BHT > procyanidin B3-3-O-gallate > (+)-gallocatechin >(+)-catechin의 순서로 나타났다.

• 한국산학기술학회논문지
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• 제1권2호
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• pp.33-40
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• 2000

본 연구는 반도체 크린룸에서 VOC(volatile organic compound)과 수분을 제거하기 위한 흡착로타에 관한 것이다. 흡착로타는 세라믹 페이퍼 허니컴 기질에 NaX 제올라이트와 TS-1 제올라이트로 만들어졌다. NaX 제올라이트는 수열합성법으로 합성되어졌으며, NaX 제올라이트 결정(2∼3 ㎛)을 seed로 합성 조성에 3∼5 wt%까지 첨가하여 5 ㎛의 균일한 NaX 제올라이트를 성장시켰다. Seed의 첨가는 seed를 첨가하지 않은 합성용액과 비교하여 결정의 크기가 크며, 균일한 NaX 제올라이트 결정을 성공적으로 합성하였다. TS-1 제올라이트는 초기 반응액의 pH를 변화시켜 합성하였다. 반응물의 pH는 10.0에서 11.5 까지의 범위를 가지며, PH 10.4에서 큰 기공(8∼10 (equation omitted))을 가진 TS-1 제올라이트(ETS-10)가 합성되는 반면 pH가 11.5에서는 작은 기공 (3∼5 (equation omitted))을 갖는 TS-1 제올라이트(ETS-4)가 합성되었다.

• 공업화학
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• 제19권1호
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• pp.66-72
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• 2008

탄소강 재질은 부식에 취약하여 용도에 따라 화성피막화 공정으로 처리하여 내부식성을 부여한다. 제이인산망간염 수화물, $MnHPO_4{\cdot}2.25H_2O$는 인산망간피막을 입히기 위한 전처리 공정용 혼합물 제품의 주성분으로 사용된다. 이 망간 함유 물질은 수용액 중에서 합성되어 여과와 건조, 그리고 일련의 건식 분쇄와 분급 과정을 통하여 생산된다. 이러한 공정은 명백히 환경친화적이지 못할 뿐만 아니라 비용 효율적이지 못하다. 본 연구에서는 더블제트 침전 기술에 기반을 두고 수용액 중에서 해당 망간 화합물을 입자 크기가 비교적 균일하게 합성하기 위한 새로운 공정기술 원리를 실험적으로 검토하였다. 안정화 첨가제의 효과들이 주사전자현미경 사진을 통하여, 생성된 결정성 침전 입자의 크기의 균일성 측면에서, 비교 검토되었다. 폴리비닐 피롤리돈과 아라비아 검이 더블제트 침전 공정에서 결정의 성장 단계를 제어하여 비교적 균일한 입자를 합성하는 안정제로서 훌륭한 효과를 발휘하는 것으로 밝혀졌다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권7호
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• pp.1-11
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• 2013

The actively soil pollution by the toxic heavy-metals like the arsenic, cadmium, lead due to the industrialization and economic activity. The uses the electrokinetic remediation of contaminated soil has many researches against the fine soil having a small size in the on going. However, it is the actual condition which the research result that is not effective due to the low surface charge of the particle and high permeability shows in the electrokinetic remediation in comparison with the fine soil in the case of the sandy soil in which the particle size is large. In this research, the electrokinetic remediation and ultrasonic wave fetch strategy is compound applied against the sandy soil polluted by the arsenic, cadmium, and lead removal efficiency of the sandy soil through the comparison with the existing electrokinetic remediation tries to be evaluated. First of all, desorption of contaminants in soil by ultrasonic extraction in the Pre-Test conducted to see desorption effective 5~15%. After that, By conducted Batch-Test results frequency output century 200 Khz, reaction time 30 min, contaminated soil used in experiment was 500 g. Removal efficiency of arsenic, cadmium, lead are 25.55%, 8.01%, 34.90%. But, As, Cd, Pb remediation efficiency less than 1% in EK1(control group).

• 한국입자에어로졸학회지
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• 제9권3호
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• pp.187-197
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• 2013

To understand the characteristics of organic aerosol(OA) at the background atmosphere of Korea, an observation of atmospheric PM10 was conducted at a Global Atmospheric Watch(GAW) station operated by the Korean Meteorological Administration at Anmyon Island during 2010. Various organic compounds were analyzed from 26 samples by using a gas chromatography-mass spectrometer. Water soluble organic carbon(WSOC) was also analyzed by using a total organic carbon(TOC) analyzer. Among 6 classes with 68 target compounds detected, the classes of n-alkanoic and alkenoic acids ($326.67{\pm}75.40ngm^{-3}$) and dicarboxylic acids ($323.74{\pm}361.89ngm^{-3}$) were found to be major compound classes in the atmosphere of Anmyon Island. Compared to the previous results reported for 2005 spring samples at Gosan site, the concentrations of organic compounds at Anmyon Island were 3-10 times higher than Gosan site due to the difference of location and sampling period. The concentrations of organic compounds were varied with the atmospheric conditions. Significant increase of the concentrations of dicarboxylic and carboxylic acids in the smog episode indicated that secondary oxidation of organic compounds was major factor to increase OA concentration during smog episode in the Anmyon Island. It was found that the compositions of the OA measured at Anmyon Island were dependent on the air parcel trajectories.

• 한국세라믹학회지
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• 제48권6호
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• pp.537-542
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• 2011

Magnesium hydroxide as a non-halogen flame retardant has increasing attention due to its non-toxicity, high decomposition temperature and smoke suppressant ability during combustion. For the application of magnesium hydroxide retardant to the textile by soaking and coating method, the prerequisite for the coating is a small particle size, stable dispersion, and adhesion to the textile. The dispersion of $Mg(OH)_2$ particles and stability of the coating was checked by monitoring the change of transmittance and backscattering by varying the types of dispersion agents, binder, solvent, and $Mg(OH)_2$ source, and their compositions in the coating. The $Mg(OH)_2$ dispersion coating was applied to PET(poly(ethylene terephthalate)) non-woven textile. The physical properties are characterized by surface morphology, amount of coating, particle dispersion, and adhesion test. The flame retardant $Mg(OH)_2$ coated textile has been compared by limited oxygen index(LOI) and thermal gravimetry and differential scanning calorimetry(TG-DSC). It was found that phosphorous additive may give synergistic effect on $Mg(OH)_2$ flame retardant coating to make the flame retardant PET non-woven textile.

• 소성∙가공
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• 제19권5호
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• pp.311-319
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• 2010

Rare earth metal Ce has a relatively low melting point and high specific gravity. Because of its significantly high affinity to oxygen, nitrogen and sulfur, it is highly usable as a steel refining agent. However, because Ce compound has relatively high specific gravity, it is difficult to be separated from molten steel through floatation, and it degrades the purity of molten steel, or may clog the nozzle in continuous casting. Such problem may be solved by using an appropriate deoxidation agent together with Ce and settling molten steel sufficiently after refining. Thus a fundamental study in the formation behavior of non-metallic inclusion in Ce added Hyper Duplex STS melts was investigated. The addition amount of Ce, melt temperature were considered as experimental variables. A main non-metallic inclusion in mother alloy is 51(wt%MnO) - 27.6(wt%SiO$_2$)- 10.9(wt%$Cr_2O_3$). Non-metallic inclusion was dramatically decreased and the particle size was fined as the amount of Ce increased. Moreover (%MnO) and (%SiO$_2$) of non-metallic inclusion were decreased. But (%$Al_2O_3$)were relatively increased. The number of non-metallic inclusion were decreased and the large particle size were increased by increasing the temperature of molten steel.

• 한국재료학회지
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• 제16권4호
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• pp.241-247
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• 2006

Structural studies have been performed on precipitation hardening discovered in $L1_2-ordered\;Ni_3(Al,Cr)$ containing 0.2 to 3.0 mol% of carbon using transmission electron microscopy (TEM). Fine octahedral precipitates of $M_{23}C_6$ appeared in the matrix by aging at temperatures around 973 K after solution treatment at 1423 K. TEM examination revealed that the $M_{23}C_6$ phase and the matrix lattices have a cube-cube orientation relationship and keep partial atomic matching at the {111} interface. After prolonged aging or by aging at higher temperatures, the $M_{23}C_6$ precipitates then adopt a rod-like morphology elongated parallel to the <100> directions. Deformation at temperature below 973 K, typical Orowan loops were observed surrounding the $M_{23}C_6$ particles. At higher deformation temperatures, the Orowan loops disappeared and the morphology of dislocations at the particle-matrix interfaces suggested the existence of attractive interaction between dislocations and particles. The change of the interaction modes between dislocation and particles with increasing deformation temperature can be considered as a result of strain relaxation at the interface between matrix and particles.

• Korean Chemical Engineering Research
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• 제58권1호
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• pp.92-97
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• 2020

본 연구에서는 제약성분인 니페디핀이 세 종류의 혼합용매에 녹는 용해도를 측정하였다. 또한 용매(아세톤, DMF, 메틸렌클로라이드)에 녹아 있는 니페디핀을 반용매(물, 헥산, 이산화탄소)를 사용하여 결정화하였고, 생성된 결정입자의 외형, 크기, 용융점 등을 측정하였다. 혼합용매로는 아세톤+물, DMF+물, 메틸렌클로라이드+헥산 혼합물이 사용되었으며, 세 혼합용매에서 모두 반용매의 비율이 증가할수록 니페디핀의 용해도가 감소하였다. 아세톤+물의 경우에는 이 혼합물의 밀도 비이상성 현상에 기인한 용해도 최대값을 나타낸 반면, 나머지 두 혼합용매에서는 이 현상이 나타나지 않았다. 반용매 결정화에 의해 생성된 니페디핀 결정의 외형은 용매와 반용매의 종류에 따라 칼날형, 입자형, 프리즘형 등으로 변화하였으며, 입자의 크기는 원재료에 비해 매우 감소하였다. 니페디핀 원재료 입자의 평균크기는 33 ㎛였으며, 결정화된 입자의 평균크기는 11.6~69.8 ㎛의 범위에 있었다. 결정화된 모든 니페디핀 입자는 동일한 열분석 결과를 보여주었으며, 이 결과는 용매와 반용매의 변화에 의해 영향 받지 않았다.

• Archives of Pharmacal Research
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• 제26권12호
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• pp.1002-1008
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• 2003

Ferulic acid (3-methoxy, 4-hydroxy cinnamic acid) is a flavoid component possessing antioxidant property. The compound is currently under development as a new drug candidate for the treatment of the dementia. The objective of this preformulation study was to determine the physicochemical properties of ferulic acid. The n-octanol to water partition coefficients of ferulic acid were 0.375 and 0.489 at the pHs of 3 and 10, respectively. Accelerated stability study for ferulic acid indicated that the t 90 value for the drug was estimated to be 459 days at $25^{\circ}C$. Ferulic acid was also found to be unstable under the relative humidity of more than 76%, probably because of the hygroscopic nature of the drug. In order to study compatibility of ferulic acid with typical excipients, potential change in differential scanning calorimetry spectrum was studied in 1: 1 binary mixtures of ferulic acid and typical pharmaceutical excipients (e.g., Aerosil, Avicel, CMC, Eudragit, lactose, PEG, PVP, starch and talc). Avicel, CMC, PVP and starch were found to be incompatible with ferulic acid, indicating the addition of these excipients may complicate the manufacturing of the formulation for the drug. Particle size distribution of ferulic acid powder was in the size range of 10-190 $\mu$m with the mean particle size of 61 $\mu$m. The flowability of ferulic acid was apparently inadequate, indicating the granulation may be necessary for the processing of the drug to solid dosage forms. Two polymorphic forms were obtained by recrystallization from various solvents used in formulation. New polymorphic form of ferulic acid, Form II, was obtained by recrystallization from 1,4-dioxane. The equilibrium solubility for Form I was approximately twice of that for Form II. The dissolution rate of Form II was higher than that of Form I in the early phase (<6 min). Therefore, these physicochemical information has to be taken in the consideration for the formulation of ferulic acid.