• 대한기계학회논문집B
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• 제25권8호
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• pp.1087-1096
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• 2001

The dynamic structures of unsteady CH$_4$/Air jet diffusion flame with a flame-vortex interaction were numerically investigated. A timed-dependent, axisymmetric computational model and a low mach number approximation were employed in the present calculation. A two-step global reaction mechanism which considers 6 species, was used to calculate the reaction rates. The predicted results including the gravitational effect show that the large outer vortices and the small inner vortices can be well simulated without any additional disturbances near nozzle tip. It was found that the temperature and species concentrations have deviated values even for the same mixture fraction in the flame-vortex interaction region. It was also shown that the flame surface is not deformed by the inner vortex in upstream region, while in downstream region, the flame surface is compressed or stretched by the outer vortex roll-up. The present unsteady jet flame configuration accompanying a flame-vortex interaction is expected to give good implications for the unsteady structures of turbulent flames.

• Tribology and Lubricants
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• 제11권5호
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• pp.59-65
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• 1995

Tribological behaviors of nitrogen incorporated amorphous diamond-like carbon films were experimentally measured under a vacuum ($3 \times 10^{-5}$ Torr) using a ball (AISI 52100 steel)-on-disk wear-rig. Nitrogen incorporated DLC films were deposited by r.f. plasma assisted chemical vapor deposition method. Mixtures of benzene and ammonia or nitrogen gases were used as the reaction gases for the r.f. PACVD, and Si (100) wafer was used as the substrate. In the tribo-test, effects of DLC film thickness and normal load in friction were measured and discussed. Results showed that friction of nitrogen incorporated DLC films from a mixture gas of benzene and ammonia was lower than that of 100% benzene, specially in the measurement of minimum coefficient of friction. Differences in frictional characteristics of nitrogen incorporated DLC films were explained with the changes in chemical structures of the films. Result also showed that friction of DLC films increased with the sliding contact cycle, which remarkably accompanied with roll-shaped wear debris. Mechanisms and roles of the polymer-like wear debris were presented and discussed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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• pp.237-243
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• 2004

A multichannel smart sound sensor capable to detect and identify sound events in noisy conditions is presented in this paper. Sound information extraction is a complex task and the main difficulty consists is the extraction of high­level information from an one-dimensional signal. The input of smart sound sensor is composed of data collected by 5 microphones and its output data is sent through a network. For a real time working purpose, the sound analysis is divided in three steps: sound event detection for each sound channel, fusion between simultaneously events and sound identification. The event detection module find impulsive signals in the noise and extracts them from the signal flow. Our smart sensor must be capable to identify impulsive signals but also speech presence too, in a noisy environment. The classification module is launched in a parallel task on the channel chosen by data fusion process. It looks to identify the event sound between seven predefined sound classes and uses a Gaussian Mixture Model (GMM) method. Mel Frequency Cepstral Coefficients are used in combination with new ones like zero crossing rate, centroid and roll-off point. This smart sound sensor is a part of a medical telemonitoring project with the aim of detecting serious accidents.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.812-817
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• 2008

A catalytic combustible sensor for LPG/LNG detection was fabricated on $Al_2O_3$ substrate using planar technology. The catalysts of Pd and Pt were added to ${\alpha}$- and ${\gamma}-Al_2O_3$ powders. The mixture of Pt, Pd and $Al_2O_3$ were homogenized by using a three roll mixer. TCR characteristics of Pt heater were optimized with the heat treatment temperature. Sensing properties were investigated as a function of the microstructure of $Al_2O_3$, the gas concentration and the variation of input voltage. ${\alpha}-Al_2O_3$ sintered at 500 $^{\circ}C$ is more suitable as LPG/LNG sensor due to good grain shape and size distribution of about 300 nm than that of ${\gamma}-Al_2O_3$ which is in irregular shape and with a particle size of 5-30 ${\mu}m$. The sensor has shown maximum output voltage of 14 mV for 1000 ppm $C_4H_{10}$ and 3.8 mV for 1000 ppm $CH_4$ at 5.0 V input voltage.

• Corrosion Science and Technology
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• 제12권1호
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• pp.1-6
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• 2013

Recently Digital TV industry has drastically been moving the illuminating system, which causes an obvious product change from PDP and LCD to LED model to provide high-definition image. Due to strong competition in the digital industry, TV manufacturers make a great efforts to reduce production cost by using low-priced materials such as steels instead of aluminum and plastic etc. In this paper we have developed a new low-priced electrogalvanized steel sheet, which has a black resin composite layer, to substitute conventional high-priced PCM steel and plastic mold for rear cover panel in the digital TV. The black resin composite was prepared by mechanical dispersion of the mixture solution that consists of high solid polyester resin, melamine hardener, black pigment, micronized silica paste, polyacrylate texturing particle and miscellaneous additives. The composite solution was coated on the steel sheet using roll coater followed by induction furnace curing and cooling. Although the coated layer has a half thickness compared to the conventional PCM steels having $23{\mu}m$ thickness, it exhibits excellent quality for the usage of rear cover panel. The new steel sheet was applied to test products to get quality certification from worldwide electronic appliance customers. Detailed discussion provides in this paper including preparation of composite solution, roll coating technology, induction curing technology and quality evaluation from customers.

• Korean Chemical Engineering Research
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• 제48권6호
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• pp.768-775
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• 2010

제올라이트(faujasite) 흡착제가 충진된 흡착탑에서 에탄/에틸렌 혼합가스의 흡착 동특성과 탈착제로 프로판을 이용한 치환탈착 시의 동특성을 실험 및 이론적으로 연구하였다. 물질수지와 에너지수지를 고려하고 다성분 흡착평형으로 이상흡착상 모델을 적용한 전산모사는 흡탈착 파과곡선 실험 결과를 잘 예측하였다. 흡착파과 시 에탄의 롤-엎은 흡착압력이 높고, 온도가 낮을수록 증가하였다. 에탄/에틸렌 혼합가스로 포화된 흡착탑으로 탈착제인 프로판을 주입하여 치환탈착할 때 탈착단계의 일정 시간 동안에 거의 100%에 가까운 에틸렌을 얻을 수 있었다. 탈착제의 흡착세기는 에틸렌의 탈착 및 재흡착 시에 큰 영향을 미치는 것으로 나타났다. 프로판 대신 흡착세기가 강한 이소부탄을 탈착제로 사용한 경우에 탈착단계 후 재흡착에서 에틸렌 흡착용량이 많이 감소하는 현상이 관찰되었다. 전산모사를 통하여 ${(q_s{\times}b)}_{C_2H_4}/{(q_s{\times}b)}_{C_3H_s}$의 비율이 0.83일 때, 즉 탈착제와 에틸렌이 거의 유사한 정도의 흡착세기를 가질 때 치환탈착공정의 성능이 우수하였다.

• 한국식생활문화학회지
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• 제14권4호
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• pp.385-393
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• 1999

The purpose of this paper on Hoe (raw beef) is to investigate various kinds of its recipes, with equal focus on seasonings and sauces as well as its main and sub ingredients. The recipes of Hoe can be broadly classified into four large groups such as Salkogi Hoe(Red meat Hoe), Hankazi Naechang-yook Hoe(made from internal organs), Jap Hoe(1)(miscellaneous Meat Hoe) and Jap Hoe(II)(rolled with a whole pinenut) while the cook books written before 1945 indicate that the number of recipes reaches up to 21. The recipe of Salkogi Hoe comprises following three steps. Cut raw beef into thin strips and season them if necessary, then sprinkling sufficient pinenut powder on the strips. Its main sauce is hot pepper paste with vinegar. The recipe of Hankazi Naechang-yook Hoe uses kidney, manyplies, liver and tripes as main ingredients. Kidney should be thinly sliced with mixture of salt, seasame salt, seasame oil, and pepper as its seasonings. Regarding Manyplies, liver and tripes, there exists two possible ways to season them after cutting into strips. You can season with sesame oil and pepper or only with salt. Main ingredients of Jap Hoe(I) consist of beef, pork, kidney, manyplies, liver and tripes, among which minimum two ingredients are selected. Ingredients selected are sprinkled with pinenut powder after cutting into thin strips. And Hot pepper paste with vinegar is used as main sauce. The recipe of Jap Hoe(II) is to cut manyplies into pieces of 2Cm by 5 Cm without removing their black part and roll each piece with a whole peanut in such a manner that the peanut sticks from rolled piece.

• 한국주조공학회지
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• 제20권2호
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• pp.122-128
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• 2000

Strip casting process is a new technology that makes a near net shape thin strip directly from molten metal. With this process, a large amount of energy and casting cost could be decreased from the abbreviation of reheating and/or hot rolling process. Ductile cast iron which has spheroidal graphite in the matrix is the most commercial and industrial material, because of its supreme strength, toughness, and wear resistance etc. But it cannot be produced to the thin strip owing to difficulty in rolling of ductile cast iron. In this study, ductile cast iron strips are produced by the twin roll strip caster, with different chemical compositions of C, Si, and Mn contents. And then heat-treated, microstructures and mechanical properties are examined. The microstructures of as-cast strip are that of white cast iron which consists of the mixture of cementite and pearlite, but the equiaxed crystal zone of the pearlite or segregation zone of cementite exists in the center region of the strip thickness, which cannot be observed in the rapidly solidified metallic mold cast specimens. This structure is supposed to be formed from the thermal distribution of strip and the rolling force. Comparing with the structures of each strips after heat treatment, increasing Si content makes smaller spheroidal graphite and more compact in the matrix, furthermore the less of Mn content makes the ferrite matrix be obtained clearer and easier. As a result of the tensile test of graphitization heat-treated strips, the yield strengths are about 250 MPa, the tensile strengths are about $430{\sim}500$ MPa, and the elongations are about $10{\sim}13%$. In the case of the strip which has the smaller and more compact spheroidal graphite in the ferrite matrix, the higher tensile strength and better drawability could be obtained.

• 한국식품영양과학회지
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• 제24권5호
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• pp.758-764
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• 1995

어린이들이 좋아하는 기호성 김치를 개발하기 위한 기초작업으로 부산시내 공, 사립 국민학교 2, 4, 6학년에 재학중인 1,100명을 대상으로 김치 선호도에 대한 설문조사를 실시하였다. 조사대상 국민학생의 68%가 김치를 좋아한다고 응답하였으나 국민학생들이 좋아하는 반찬들(계란말이, 단무지, 김구이, 햄.소시지.미니돈까스, 콩나물무침, 호박나물, 장조림 등) 중에서의 김치의 선호도(17.6%)는 햄.소시지.미니돈가스(54.7%)에 이어 2위를 차지하였으나 그 선호 정도는 상당히 낮아 실제적인 선호도와는 차이가 있는 것으로 나타났다. 김치의 매운맛은 국민학생들이 김치를 가장 싫어하는 이유인 동시에 김치를 가장 좋아하는 이유로 나타나 김치의 특성을 대표하는 맛으로 생각되었다. 국민학생들이 선호하는 김치의 종류는 배추김치, 깍두기, 물김치, 총각김치, 오이김치 순이었다. 김치 담금 재료 중에서는 배추를 가장 좋아하고 생강, 마늘, 파, 젓갈 등 강한 냄새를 내는 것을 싫어하는 것으로 나타났다.

• 한국식품영양과학회지
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• 제42권12호
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• pp.1949-1957
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• 2013

본 연구에서는 6개의 지역(강원도, 경기도, 경상도, 서울, 전라도, 충청도)에서 채취한 가공 및 외식식품 38종에 함유되어 있는 ${\beta}$-carotene 및 retinol의 함량을 조사하였다. 이들 지용성 비타민들은 알칼리를 이용한 직접 검화법과 용매추출법을 병행하여 수행하였다. 면류 식품 14종 중에서 ${\beta}$-carotene 함량은 비빔국수와 쫄면에서 각각 평균 442.43 ${\mu}g/100g$과 301.39 ${\mu}g/100g$이 검출되며 가장 높은 함량을 나타내었다. 비타민 A(${\mu}gRE$) 함량은 비빔국수와 회냉면, 쫄면, 비빔냉면이 각각 77.5 RE와 61.3 RE, 56.4 RE, 53.2 RE이었다. 만두류 식품 4종에서는 김치만두에서 ${\beta}$-carotene 197.64 ${\mu}g/100g$으로 가장 높게 검출되었으며, 비타민 A(${\mu}gRE$) 함량은 33.3 RE이었다. 떡류 제품 12종에서는 매운 떡볶이와 모듬찰떡에서 ${\beta}$-carotene 함량이 각각 평균 205.11 ${\mu}g/100g$과 41.33 ${\mu}g/100g$으로 검출되었으며, retinol은 매운 떡볶이(1.65~10.45 ${\mu}g/100g$)에서만 검출되었다. 매운 떡볶이와 모듬찰떡의 경우, 비타민 A(${\mu}gRE$)의 함량은 각각 39.67 RE와 6.89 RE로 환산하였다. 이는 하루 필요한 비타민 A(700 ${\mu}gRE$)의 1~6%에 해당하는 함량이다. 제빵류 8종에서는 ${\beta}$-carotene 함량이 야채고로케(110.43~192.29 ${\mu}g/100g$), 햄&치즈샌드위치(33.07~116.57 ${\mu}g/100g$), 페이스트리빵(33.69~104.87 ${\mu}g/100g$), 마늘빵(빵집, 33.88~81.21 ${\mu}g/100g$), 버터크림빵(빵집, 31.61~85.84 ${\mu}g/100g$)에서 높게 검출되었다. 비타민 A(${\mu}gRE$)의 함량은 제빵류 중에서 페이스트리빵과 버터크림빵(빵집), 모닝빵들이 각각 77.3 RE와 51.2 RE, 41.4 RE를 나타내며 가장 높은 함량을 보였다.