• Journal of Food Hygiene and Safety
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• v.13 no.1
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• pp.24-28
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• 1998

Korean sesame oil mixed with corn oil and Chinese sesame oil were subjected to instrumental determination for fatty acid composition, sesaminol and sesamin contents, and induction period by AOM test to obtain basic data for ascertaining the truth of pure sesame oil, respectively. In sesame oil mixed with corn oil, stearic acid content of sesame oil containing above 20% corn oil was remarkably discriminated from that of pure sesame oil. Oleic and linoleic acid contents of sesame oil with 10% corn oil were significantly differnt from that of pure sesame oil. Stearicllinoleic acid ratio of sesame oil mixed with corn oil dcreased in proportion to corn oil content in sesame oil. Sesamolin and sesamin contents of sesame oil containing 30% corn oil were lower 18.3% and 21.0% than those of pure sesame oil, respectively. Induction periods of sesame oil by AOM were 8.14~9.24 hrs in Chinese sesame oil and sesame oils including 20% and 40% corn oils, but around 16hrs in Korean pure sesame oil. Based on the above results, it is considered that the comparisons of fatty acids, sesaminol and sesamin contents, and induction period by AOM test might be one of the potential criteria in discriminating between pure sesame oil and sesame oil mixed with corn oil.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.5
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• pp.233-240
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• 2012

White LEDs (light-emitting diodes) are promising new-generation light sources which can replace conventional lamps due to their high reliability, low energy consumption and eco-friendly effects. This paper briefly reviews recent progress of oxy/nitride host phosphor and quantum dot materials with broad excitation band characteristics for phosphor-converted white LEDs. Among oxy/nitride host materials, $M_2Si_5N_8$ : $Eu^{2+}$, $MAlSiN_3$ : $Eu^{2+}$ M-SiON (M = Ca, Sr, Ba), ${\alpha}/{\beta}$-SiAlON : $Eu^{2+}$ are excellent phosphors for white LED using blue-emitting chip. They have very broad excitation bands in the range of 440~460 nm and exhibit emission from green to red. In this paper, In this review we focus on recent developments in the crystal structure, luminescence and applications of the oxy/nitride phosphors for white LEDs. In addition, the application prospects and current trends of research and development of quantum dot phosphors are also discussed.

• Journal of the Korean Ceramic Society
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• v.34 no.1
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• pp.31-36
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• 1997

The effects of 0 to 10mol% excess MgO addition on the microstructure and dielectric properties in 30Pb(Mg1/3Nb2/3)O3-20PbTiO3-50Pb(Mg1/2W1/2)O3 ternary system were investigated. Samples were prepared by mixed oxide and precursor methods to compare the role of excess MgO. Excess MgO enhanced grain growth and increased dielectric constant. The dielectric constant and tesmperature dependence of dielectric constant of the sample sintered at 100$0^{\circ}C$ with 5mol% MgO were above 5,000 and +25% to -50% from - 55$^{\circ}C$ to 1$25^{\circ}C$, respectively. For these specimens the phases percent were mainly perovskite and Pb2WO5, which was confirmed by XRD analysis. Also the amount of cubic pyrochlore Pb3Nb4O13 and PbWO4 were de-creased with sintering temperature and MgO addition. BSE image showed the chemical inhomogeneous dis-tribution. Crystal phase formed at each sintering temperature and the chemical inhomogeneous distribution caused the decrease of the temperature dependence of dielectric constant.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.2
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• pp.144-151
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• 1991

Quality stability and utilization of sardine protein concentrates were investigated. pH, water activity and amino-nitrogen contents of autoclaved and boiled products were little changed during the storage of 60 days. Available lysine contents of the both products at the initial stage of storage were 5.58g/16g-N and 5.69g/16g-N, respectively. But the available lysine contents and digestibility of the both products decreased slightly with increasing of storage time. Lipophilic and hydrophilic brown pigment formation of the both products increased during storage of 60 days, but peroxide value(POV) and thiobarbituric acid(TBA) value decreased. Total amino acid contents of the both products were in the range of $88.99{\~}89.90g/16g-N$, and the predominant ones were glutamic acid, aspartic acid, leucine and lysine. From the sensory scores of model snack, it is concluded that the sardine protein concentrate can be used as a source material for snack.

• Journal of the Korean Society of Radiology
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• v.3 no.1
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• pp.17-21
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• 2009

The Recently, large area matrix-addressed image detectors are investigated for X-ray imaging with medical diagnostic and other applications. In this paper, a new flat panel gas detector for diagnostic X-ray imaging is proposed, and its characteristics are investigated. The research of flat panel gas detector is not exist at all. Because of difficulty to inject gas against to atmospheric pressure. So almost gas detector made by chamber shape. We made flat panel sample by display technique. (ex: PDP, Fed, etc.) The experimental measurements, the transparent electrodes, dielectric layer, and the MgO protection layer were formed in front glass. And, the X-ray phosphor layer and address electrodes are formed in the rare glass. The dark current, the x-ray sensitivity and linearity as a function of electric field were measured to investigate the electrical properties. From the results, the stabilized dark current density and the significant x-ray sensitivity were obtained. And the good linearity as a function of exposure dose was showed in wide diagnostic energy range. These results means that the passive matrix-addressed flat panel gas detector can be used for digital x-ray imaging.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.591-591
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• 2012

본 연구는 Transparent conducting oxide (TCO, 산화물투명전극)를 이용한 박막태양전지 효율향상에 관한 것으로, 이중의 TCO층(Double-stacked TCO layer)의 효과적인 광학 및 전기적 설계에 관한 것이다. 기존 박막 태양전지에서는 투명전극 TCO layer로서, ITO (Indium-Tin-Oxide), FTO (Fluorine- Tin-Oxide), 및 AZO(Aluminum-doped Zinc Oxide) 등을 사용해 왔다. 각 TCO layer마다 장점이 있지만 단점 또한 존재한다. ITO의 경우 높은 전기적 특성을 가지는 반면 수소 플라즈마에 취약하고 기계적 강도에 취약해 ITO 단일층만으로 박막 태양전지에 적용하는 것에 제한을 받는다. 한편, AZO의 경우 전기적 특성도 우수할 뿐만 아니라 수소 플라즈마에도 내구성이 강한 장점이 있지만, 일함수가 p형 반도체보다 낮아 Schottky junction이 되어, 높은 전위장벽이 형성된다. 이는 정공의 이동을 방해하고, 정공의 축적이 일어나서 순방향 전압을 인가할 때 많은 전류의 감소를 가져온다. 또한, AZO와 p형 반도체 사이의 높은 직렬저항으로 인해 광전압(Voc, Open circuit voltage)와 충실률 (FF, Fill factor)가 떨어진다는 단점이 있다. 본 실험에서는 ITO/AZO 2중구조의 TCO층을 적용하여 상기의 문제점을 해결하고자 한다. 이중 구조 TCO층은 Magnetron sputter system을 이용하여, 단계적으로 증착되었다. 빛이 입사하는 유리에 ITO를 제1전도층으로 증착하였는데, ITO는 입사광의 투과도와 전기전도성이 우수하다. 제2전도층으로는 AZO층을 이용하였으며, 실리콘 반도체층과 접하게 된다. AZO는 실리콘 증착시 발생하는 수소 플라즈마에 안정적이고, 물리적 강도 또한 우수한 장점이 있다. 이중 구조층위에 실리콘 광흡수층(Si absorber)을 증착하였으며, pin 구조를 가진다. 기존, 단일막 TCO층과 2중구조 TCO층을 이용하여, 실리콘 박막 태양전지를 구성하였다. 이때, ITO/AZO의 2중구조를 적용하였을 때 태양 전지 특성이 크게 향상된 결과를 얻을 수가 있었다. 특히, 전류밀도의 경우 ITO, FTO, AZO 각각 14.5 mA/cm2, 11.2 mA/cm2, 8.18 mA/cm2를 나타낸 반면 ITO/AZO 2중구조의 경우 약 17mA/cm2 로 크게 향상 되었고, 태양전지 변환 효율도 각각 7.5%, 6.9%, 4%에서 ITO/AZO 2중 구조의 경우 8.05%로 크게 향상되었다. 본 발표에서는 2중구조 TCO를 이용한 현공정에 적용 가능한 박막태양전지 효율향상 기법에 대해 논의하고자 한다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.4
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• pp.253-259
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• 1996

Ammonia microdiffusion method and colorimetric measurement are described for the nitrogen determination. The diffusion of ammonia could be successfully induced by using a microdiffusion cell. It is a simple and rapid technique, which is suitable for transforming the nitrogen in digests into $NH_4CI$ for the colorimetric N determination with ammonia color reagent. Above 99% of N recovery were obtained with microdiffusion up to 15 hours. The coloration method of collected $NH_4CI$ for the colorimetric N determination was also estabilshed with a scanning in U.V. spectrophotometer. Under the proposed coloration method (0.5 mL of sample digest, 4.0 mL of $H_2O$ and 0.5 mL of ammonia color reagent), a maximal absorbance was observed at 410 nm. The kinetic measurement of absorbance showed a high stability from 5 to 45 minutes after color development. Absorbance was directly proportional to the amount of $NH_4^+-N$ present. The microdiffusion-ammonia coloration method was successfully applied to the nitrogen determination in the forms of protein-N or total -N in plant tissue. Comparing with Kjeldahl distillation method, the values obtained with described method were slightly higher and more reliable.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.986-993
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• 1994

As a part of development of traditional foods, mugwort boogag and dry laver boogag were fried insoybean oil, and BHA or tocopherol-added soybean oil. They were wrapped up in opp vinyl film, and preserved at $4^{\circ}C(RH{\;}40{\pm}5%){\;}and{\;}25^{\circ}C(RH{\;}80{\pm}5%)$. During the storage of bobogags, acid value, peroxide value, and TBA value were investigated. Changes of sensory evaluation and texture profile were also examined. Boogags were manufactured by washing the raw materials. drying in the shade, mixing them with glutinous rice flour, and hot-air drying up it to 13 % of moisture contents after dryed it up to 80% of moisture contents on dry table for 23days, in order. These boogags were packaged to manufacture goods with dryed state or fried at $160^{\circ}C$ for 10 sec. Acid value, peroxide value, and TBA value of boogags which preserved at $4^{\circ}C$ generally appeared lower than at $25^{\circ}C$. As storage time goes by, moisture contents of bobogagas preserved at $25^{\circ}C$ increased and its quality were gradually deteriorated. When the boogags were fried in BHA(0.01%) and tocopherol (0.01%) added soybean oil, changes of acid value, peroxide value, TBA value were generally low. During the storage of bobogagas antioxidant effect of BHA was higher than that of tocopherol. Texture was inclined to decrease as storage time goes, by that of boogags preserved at $4^{\circ}C$ was a little more satisfactory. Hardness was also high.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.2
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• pp.141-151
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• 2013

The nano-surface modification techniques could be classified; internal modifications which enhance surface roughness and porosity in nano level and external modifications as nano particle coating. Nano-modified implant surface has various morphograpies such as nanotube, nanopit, nanonodule and polymorphic structures. Creating surface depends upon preparation method and material, however, there is no standard preparation technique not yet. The nano-modified surfacet is electrochemically stable comparing with the surface modified in micron level. Nano-modified surface has little cytotoxicity, stimulates osteoblast proliferation and differentiation. Moreover, it decreases soft tissue intervention by interrupting the proliferation of fibroblast. Nanostructure has similar size and shape with cells and proteins, consequently leads to good biocompatibility and enhanced osseointegration. However, the actual effect in vivo is limited, due to the distance of effect. Even if nano-modified surface has antibiotic property due to photocatalysis, short duration time makes clinical application questionable. Further investigations should focus on the optimal nano-modified surface, which has many potentials.

• Journal of the Korean Chemical Society
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• v.47 no.1
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• pp.13-18
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• 2003

The effect of ultrasonic decomposition was introduced to develop a pretreatment method for the analysis of potassium ion in human urine by potentiometry. N-(4’-benzo-15-crown-5)-anthracene-9-imine, which has a good selectivity coefficient for potassium against ammonium, was used as an ion-selective material for the determination of potassium in urine with relatively high concentration of $NH_4{^+}$. Protenis in urine be removed by 85.1% when the sample acidified with 1.0 M $HNO_3$ was preteated for 100 s by sonication. Potential response of the membrane electrode in the pretreated urine had a slope of 54.6(${\pm}0.2,\;n=5$) mV/decade over the linear range of log $[K^+]$=-5~-1(r=0.9997). When an oxidant, $H_2O_2$, was addwd to the urine sonicated with $HNO_3$, the deproteinization increased 10% more than that in case if only $HNO_3$ and then the maximum ratio of ca. 95% was obtained. Moreover, the Nernstian slope for $K^+$ added to the urinary sample increased to 56.7(${\pm}0.1,\;n=3$) mV/decade. When the calibration curves were measured, the slopes did not vary even after the electrode was successively used 20 times with ultrasonic cleaning. The results showed that an ultrasonic pretreatment method provides simplicity in use, reduced treatment time and improved potentiometric characteristics of the membrane as the method effectively removes ca. 95% of proteins in urine.