• Polymer(Korea)
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• v.33 no.4
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• pp.353-357
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• 2009

Spray drying is an effective and stable process, which has been widely used to produce pharmaceutical powders. In the traditional spray drying process, it was not quite easy to control the aggregation and the size of particles. Particularly, the preparation of polymeric particles was relatively hard compared to the preparation of food and pharmaceutical ingredients, typically organic materials of small molecular weights. In this study, modification of a conventional spray dryer was tried to use electrical charge and co-axial nozzles to prepare polymeric particles. Poly(ethylene glycol) and poly (D,L-lactide-co-glycolide) were used as the inner polymeric materials, and lactose as the outer shell materials. The results showed that electrohydrodynamic spray-dried particles had a relatively uniform size and particle morphology, and the aggregation of particles could be suppressed compared to the conventional spray-dried particles. The electrohydrodynamic spray-dried powders consisted of spherical particles of $2{\sim}5{\mu}m$ diameters.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.37-41
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• 2000

This study has been carried out to investigate the chemical composition of Acorus calamus L., a wild plant (Chang Po) which has long been used as a medicine or a hair rinse in Korea and China. Potassium was found to be the most predominant mineral in leaf and root, followed by calcium, magnesium, and phosphorus, in a decreasing order. Contents of potassium in leaf and root account for 54a.65 mg% and 242.87 mg%, respectively. Contents of these minerals in leaf were higher value than that in root. Glucose and fructose were found to be the major free sugars in leaf and root. Malic acid was the most abundant organic acid of leaf and root, and followed by citric acid. Fourteen different kinds of fatty acids were identified from the leaf and root. Content of unsaturated fatty acids. such as linolenic, and linoleic acid ware higher than that of saturated fatty acids. Content of total amino acids was 3 times higher in leaf than that in root. Leucine was the major amino acid in leaf and glutamic acid in root.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1613-1618
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• 1999

Extracts of Citrus sudachi juice and peel were obtained by several organic solvents such as hexane, acetone, ethyl acetate and methanol. Their antimicrobial spectrum were determined against 14 strains of gram positive and 4 strains of gram negative bacteria by paper disk method and minimal inhibitory concentration (MIC) was also obtained. Antimicrobial activities of solvent extracts from Citrus sudachi juice showed stronger than those of solvent extracts from peel. Acetone extract from juice showed the strongest antimicrobial activity among extracts, but the hexane extract did not show antimicrobial activities on tested target strains. The MIC was differant among tested strains; i.e. 0.5% (v/v) to Bacillus subtilis, 1% to Pseudomonas fragi, 1.5% to Listeria monocytogenes and Escherichia coli O157:H7, 2% to Propionibacterium acnes and Salmonella typhimurium, and 2.5% to Staphylococcus aureus.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1420-1425
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• 1998

Rice wines, Yakju-type, were brewed with typical raw materials plus powdered acorns, and storage qualities of the fermented wines were examined. Initial optical densities of the acorn added-rice wines were shown around 0.116 at 660 nm and then decreased to $0.06{\sim}0.075$ after 10 days storage at $4^{\circ}C$. Organic acid contents in the acorn added-rice wines were lower than that of the control: the contents were lactic, succinic, citric, malic, oxalic and fumaric acid in order; and gallic acid, a kind of tannic substances was 0.39 mg%. Peroxide values of the acorn added-rice wines were not markedly changed for 9 days, remaining as low as $2{\sim}3\;meq\;kg^{-1}$ lard of lard, but that of the control was increased to $265\;meq\;kg^{-1}$ lard. As the results of clarity, acidity and antioxidation, the acorn added-rice wines appeared to be preservable, owing to tannic substances extracted from acorn powder.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.1
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• pp.81-88
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• 2010

Thermal annealing and electromigration test were performed at $150^{\circ}C$ and $4{\times}10^3\;A/cm^2$ conditions in order to investigate the effect of PCB surface finishs on the growth kinetics of intermetallic compound (IMC) in Sn-3.0Ag-0.5Cu solder bump. The surface finishes of the electrodes of printed circuit board (PCB) were organic solderability preservation (OSP), immersion Sn, and electroless Ni/immersion gold (ENIG). During thermal annealing, the OSP and immersion Sn show similar IMC growth velocity, while ENIG surface finish had much slower IMC growth velocity. Applying electric current accelerated IMC growth velocity and showed polarity effect due to directional electron flow.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2005.05a
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• pp.213-215
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• 2005

The metal complexes can be influenced not only by the central metal atoms and the substituent groups, but also by the native of the chelating atoms. For example, near-infrared absorbing chromophores were synthesized by the reaction of phenylenediamine derivatives with a solution of pottassium hydroxide followed by the addition of nickel(II) chloride. These dyes provide absorbing infrared light over 780-840 nm with an extinction coefficient of $2.5-6.0{\times}10^4$. By introduction of alkyl, alkoxyl, cyano, and other functional group into the parent dye, these dyes greatly improved the solubility in organic solvent. New near-infrared absorbing donor-acceptor chromophores have been investigated by varying the electron donating and accepting strength of the two halves of the molecule. The cyanine chromophores permit the simplest way of obtaining systems that absorb well into the near-infrared region of the spectrum. Cyanine dyes possess high extinction coefficients that initially increase with Increasing chain length. These chromophores could be useful in near-infrared optical materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.33-33
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• 2007

SoP-L 공정은 유전율이 상이한 재료를 이용하여 PCB 공정이 가능하고 다른 packaging 방법에 비해 공정 시간과 비용이 절약되는 잠정이 있다. 본 연구에서는 SoP-L 기술을 이용하여 Si 기판의 함몰에 판한 공정의 안정도와 함몰 시 제작된 때턴의 특성의 변화에 대해 관찰 하였다. Si 기판의 함몰에 Active device를 이용하여 특성의 변화를 살펴보고 공정의 안정도를 확립하려 했지만 Active device는 측정 시 bias의 확보와 특성의 민감한 변화로 인해 비교적 측정이 용이하고 공정의 test 지표를 삼기 위해 passive device 를 구현하여 함몰해 보았다. Passive device 의 제작 과정은 Si 기판 위에 spin coating을 통해 PI(Poly Imide)를 10um로 적층한 후에 Cr과 Au를 seed layer로 증착을 하였다. 그리고 photo lithography 공정을 통하여 photo resister patterning 후에 전해 Cu 도금을 거쳐 CPW 구조로 $50{\Omega}$ line 과 inductor를 형성하였다. 제작 된 passive device의 함몰 전 특성 추출 data와 SoP-L공정을 통한 함몰 후 추출 data 비교를 통해 특성의 변화와 공정의 안정도를 확립하였다. 차후 안정된 SoP-L 공정을 이용하여 Active device를 함몰 한다면 특성의 변화 없이 size 룰 줄이는 효과와 외부 자극에 신뢰도가 강한 기판이 제작 될 것으로 예상된다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.36-36
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• 2007

본 논문에서는 SoP-L(System on Package-Laminates) 기술을 이용하여 이종의 유전율을 가진 유기물 적층 기반의 수동소자를 이용한 GSM/DCS 대역 분리용 diplexer를 설계, 제작하였고 그 특성을 고찰하였다. SoP-L 기술은 LTCC기술과 같은 타 SoP 기술과 비교해서 이종의 물질을 접합하는데 용이하고 공정비용이 저렴하다. 이러한 장점을 이용하여 캐때시터는 유전율 40의 고유전율 재료를 사이에 두고 구성하였고, 인덕터 부문에는 유전율 4률 적용, 정방혈 스파이럴 구조로 두 개 층으로 구성하여 소형화를 이룰 수 있었다. 제작 시에 구리와 유기물을 적층, patterning 하였고, 수직 via hole 을 형성하고 구리의 무전해, 전해 도금 과정을 거쳐 각 소자를 연결하였다. 이러한 과정을 거쳐 제작된 diplexer의 GSM 저역 통과 필터는 0.52 dB이하의 삽입손실과 20 dB 이상의 반사손실을 가지고 DCS 통과 대역 부근에 notch 가 존재하도록 설계함으로써 DCS 통과 대역에서 17 dB 이상의 저지특성을 나타내었다. DCS 고역 통과 필터는 1.2 dB 이하의 삽입손실과 16 dB 이상의 반사손실을 가지며 GSM 통과 대역 부근에 notch를 가지도록 설계하여 GSM 통과대역에서 32 dB 이상의 저지특성을 나타내었다.

• Polymer(Korea)
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• v.28 no.5
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• pp.367-373
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• 2004

Novel non-conjugated blue light-emitting copolymers containing perylene and triazine moieties as light emitting and electron transporting units, respectively in the polymer side chain were synthesized. The resulting copolymers were soluble in most organic solvents such as chlorobenzene, THF, chloroform and benzene. The single-layered electroluminescence (EL) device consisting of indium tin oxide (ITO) /copolymer/aluminium (Al) exhibited a maximum external quantum efficiency ($0.003\%$) and a good carrier balance when the triazine content was $30\%$. In particular, the device emitted blue light (479 nm) corresponding to the emission of perylene moiety. The drive voltage was observed at 5 V and the CIE coordinate was x=0.16, y=0.17.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.3
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• pp.229-236
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• 2017

In this study, a direct contact membrane module was manufactured to be used in a pilot scale membrane distillation process to treat $3m^3/day$ of the digestate produced from anaerobic digestion of livestock manure. In order to investigate the performance of the membrane module, permeate flux was measured with and without spacer inside the module under various condition of temperature difference and cross flow velocity (CFV) through the membrane surfaces. Flux recovery rate after chemical cleaning was also investigated by applying three different cleaning methods. Additionally, thermal energy consumption was theoretically simulated based on actual pilot plant operation conditions. As results, we observed flux of the module with spacer was almost similar to the theoretically predicted value because the installation of spacer reduced the channeling effect inside the module. Under the same operating condition, the permeate flux also increased with increasing temperature difference and CFV. As a result of chemical in-line cleaning using NaOCl and citric acid for the fouled membranes, the recovery rate was 83.7% compared to the initial flux when NaOCl was used alone, and 87% recovery rate was observed when only citric acid was used. However, in the case of using only citric acid, the permeate flux was decreased at a rapid rate. It seemed that a cleaning by NaOCl was more effective to recover the flux of membrane contaminated by the organic matter as compared to a cleaning by citric acid. The total heat energy consumption increased with increasing CFV and temperature difference across the membrane. Thus, further studies should be intensively conducted to obtain a high permeate flux while keeping the energy consumption to a minimum for a practical application of membrane distillation process to treat wastewater.