• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.155-155
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• 2012

기존의 플로팅 타입의 비휘발성 메모리 소자는 스케일 법칙에 따른 인접 셀 간의 간섭현상과 높은 동작 전압에 의한 누설전류가 증가하는 문제가 발생을 하게 된다. 이를 해결하고자 SONOS (Si/SiO2/Si3N4/SiO2/Si) 구조를 가지는 전하트랩 타입의 비휘발성 메모리 소자가 제안되었다. 하지만 터널링 베리어의 두께에 따라서 쓰기/지우기 특성은 향상이 되지만 전하 보존특성은 열화가 되는 trad-off 특성을 가지며, 또한 쓰기/지우기 반복 특성에 따라 누설전류가 증가하게 되는 현상을 보인다. 이러한 특성을 향상 시키고자 많은 연구가 진행이 되고 있으며, 특히 엔지니어드 터널베리어에 대한 연구가 주목을 받고 있다. 비휘발성 메모리에 대한 엔지니어드 기술은 각 베리어; 터널, 트랩 그리고 블로킹 층에 대해서 단일 층이 아닌 다층의 베리어를 적층을 하여 유전율, 밴드갭 그리고 두께를 고려하여 말 그대로 엔지니어링 하는 것을 뜻한다. 그 결과 보다 효과적으로 기판으로부터 전자와 홀이 트랩 층으로 주입이 되고, 동시에 다층을 적층하므로 물리적인 두께를 두껍게 형성할 수가 있고 그 결과 전하 보전 특성 또한 우수하게 된다. 본 연구는 터널링 베리어에 대한 엔지니어드 기술로써, Si3N4를 기반으로 하고 높은 유전율과 낮은 뉴설전류 특성을 보이는 ZrO2을 두 번째 층으로 하는 엔지니어드 터널베리어 메모리 소자를 제작 하여 메모리 특성을 확인 하였으며, 또한 Si3N4/ZrO2의 터널베리어의 터널링 특성과 전하 트랩특성을 온도에 따라서 특성 분석을 하였다.

• Analytical Science and Technology
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• v.16 no.6
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• pp.458-465
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• 2003

The HS (headspace)-SPME (Solid phase microextraction) as rapid and simple method was performed for the determination of volatile fatty acids (VFAs) from the aqueous samples. In-fiber derivatization of VFAs with 1-Pyrenyldiazomethane (PDAM) was applied to improve their sensitivity of detection. In SPME procedure, typical parameters such as effects of solution pH, and salting out reagent and ultrasonication were investigated to improve the extraction efficiency. Based on the developed method, VFAs in wastewater samples were determined by gas chromatography / mass spectrometry-selected ion monitoring (GC/MS-SIM) mode.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.465-470
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• 2006

Siloxanes are widely used in industrial processes and consumer products. When landfill gas is used as fuel for gas engines, volatile siloxane in landfill gas causes serious damage to gas engines and pretreatment facilities. In this study, the applicability of various clay minerals was evaluated as the alternative adsorbents of activated carbon. SEM and BET analyses of illite, vermiculite, and activated carbon were performed for comparing those physical properties. Siloxane adsorption capacities of illite and vermiculite were estimated very high to 1.7 g/g illite, 3.8 g/g vermiculite respectively through the adsorption experiments of D5 siloxane.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.390-390
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• 2013

유기물을 이용하여 제작한 비휘발성 메모리 소자는 저전압 구동, 간단한 공정과 플렉서블 모바일에 응용 가능성 때문에 많은 연구가 진행되고 있다. 나노복합체를 사용하여 제작한 비휘발성 메모리 소자의 전기적 특성에 대한 연구가 많이 진행되었으나 고분자를 저장매체로 사용한 메모리 소자의 전기적 특성에 대한 연구는 미흡하다. 본 연구에서 poly (methylmethacrylate) (PMMA)와 poly (3-hexylthiophene) (P3HT) 혼합한 용액을 이용하여 제작한 메모리 소자의 전기적 특성을 연구하였다. P3HT와 PMMA를 같이 클로로벤젠에 용해한 후 초음파 교반기를 사용하여 두 물질을 고르게 섞었다. Indium-tin-oxide가 코팅된 유리 기판 위에 제작한 고분자 용액을 스핀 코팅하고, 열을 가해 용매를 제거하였다. P3HT박막 위에Al을 상부전극으로 열증착하여 소자를 제작하였다. 제작된 소자의 전류-전압(I-V) 측정결과는 같은 전압에서 전도도가 큰 ON 상태와 전도도가 작은 OFF 상태의 큰 ON/OFF 전류비율을 가진 전류의 히스테리시스를 보여주었다. P3HT를 포함하지 않은 소자의 I-V 측정결과는 전류의 히스테리시스 특성이 보이지 않았고 이것은 P3HT 박막이 메모리 특성을 나타내는 저장매체가 됨을 알 수 있었다. 소자의 전류-시간 특성 측정 결과는 전류의 ON/OFF 비율이 시간에 따라 큰 감쇠 현상 없이 오랫동안 지속적으로 유지됨을 보여줌으로 소자의 동작 안정성을 알 수 있었다.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.298-304
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• 1996

Thirty-nine samples of roasted sesame seed oils were sensorially evaluated in terms of nutty odor, burnt odor and overall desirability, and their volatile compounds quantitatively analysed using direct sampling capillary GLC. Five volatile compounds were appeared to be significant for the sensory Properties of sesame oils through the multivariate analytical techniques such as stepwise discriminant analysis. canonical discriminant analysis, discriminant analysis and principal component analysis. The most important compounds were 2,5-dimethylpyrazine and 2-methylpyrazine which could be effectively used as chemical indicators related to nutty and burnt odor of sesame oils, respectively. The sesame oils which have represented a good grade of overall desirability have been always kept $35.82{\sim}4.43$ ppm of 2,5-dimethylpyrazine and also $28.90{\sim}6.35$ ppm of 2-methylpyrazine.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.4
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• pp.393-398
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• 2010

This study prepared and utilized an imitation trial test chamber for a petroleum spill to predict the concentration of discharged Volatile Organic Compounds in the air at the time of Tae-An peninsula's petroleum spill, which happened in December, 2007. The petroleum spill imitation trial test chamber measured and analyzed the concentration variation of total VOCs. As the ambient air velocity increased, so the concentration of VOCs decreased; and as the water temperature rose, the concentration of VOCs increased. Furthermore, it appears that total concentration of VOCs decrease by more than 90% 6 days after the initial petroleum spill compared to the initial concentration of VOCs.

• Polymer(Korea)
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• v.28 no.1
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• pp.35-40
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• 2004

The formation mechanism of void defect which deteriorate composite's property is various according to each composite process. In this paper, void formation and growth mechanism is analyzed by thermal analysis and GC/MS. We made a vacuum chamber for observing pressure effect. Thermal analysis has been done in various condition. Elements of volatiles during resin curing were turned out by GC/MS. The most of volatiles of polyester were composed of styrene (over 80%) and a small quantity of toluene. In case epoxy resin, butyl glycidyl ether was the main element of volatiles (over 90%). We concluded that the original sites of void growth existed in resin and they were eliminated by vacuum and heating process. And the growth of void was influenced by water, diluents, solvent, and reactants in resin.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.187-191
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• 2016

The objective of this study was to analyze the volatile compounds in rice under various milling degrees using a mass spectrometry-based electronic nose and discriminant function analysis (DFA). Less volatile components were more frequently found in rice with a lower milling degree. Milling degree resulted in a shift of DF1 to the left side of the DFA plot. This indicated that the DF1 scores were correlated with the milling degree of rice. Brown rice was found to have more volatile components regardless of the milling degree. Thus, rice prepared at different milling degrees could be effectively discriminated with electronic nose analysis. Moreover, more volatile components were detected with an increase in storage time. A slight change in volatile components was found with an increase in the milling degree. The electronic nose could predict the milling degree and storage time of rice.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.136-141
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• 1993

A curd yogurt was prepared from milk added with skim milk powder or four kinds of cereal. The effect of cereals at 2%(w/v) level on the pattern of volatile aroma compounds in curd yogurt was investigated. Acetaldehyde, acetone, ethanol, diacetyl, butanol and acetoin in curd yogurt were detected by gas chromatographic analysis. Among these compounds, acetaldehyde, ethanol, diacetyl and acetoin were produced during fermentation by Lactobacillus acidophilus (KCTC 2182). The addition of cereals did not affect markedly general pattern of volatile aroma compounds in curd yogurt. The amount of acetoin and ethanol markedly increased until the first 6 hours of fermentation, and then increased mildly until 24 hours. The amount of diacetyl markedly increased until the first 6 hours and then decreased slightly. Acetaldehyde was first detected by gas chromatograph after 18 hours of fermentation.

• Applied Biological Chemistry
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• v.36 no.2
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• pp.111-114
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• 1993

The volatile components of cooked glutinous rice were investigated. Among more than 100 volatile components of fresh cooked rice, the predominant one was hexanal followed by pentanal, butanal, octanal, heptanal, noananal, acetone and toluene. These eight components comprised about 85% of the total volatiles, and the hexanal comprised about 86% total amount of the eight volatile components. the amount of the eight volatile components and hexanal in cooked glutinous rice were six and nine times more than that of cooked nonglutinous rice, respectively. The amount of volatile components in cooked glutinous rice stored for 72 hours at $70^{\circ}C$ was same with that of in nonglutinous rice immediately after cooking.