• 한국식품위생안전성학회지
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• 제13권4호
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• pp.419-424
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• 1998

Zearalenone 검출을 위하여 Z-M-26 hybridoma cell을 mouse의 복강에 투여한 후 생산, 정제한 항체와 합성한 Zearalenone-oxime-OVA conjugate를 이용하여 ELISA법을 확립하였다. Carbonyl buffer로 희석한 Zearalenone-oxime-OVA conjugate를 4$^{\circ}C$에서 하룻밤 coating 하고 1% BSA용액으로 하룻밤 blocking한 다음, 1,000배 희석한 항체를 Zearalenone 또는 시료와 혼합하여 하룻밤 반응시키는 것이 효과적이었다. 또한 2차 항체와 기질용액의 반응시간은 각각 1시간, 30분이 적당하였고, 발색된 반응액 450nm에서 측정하였다. 이 분석법의 결과 0.1~100 ppb의 Zearalenone이 측정 가능하였으며, 본 실험에서 확립한 indirect competitive ELISA법은 농산물 중 Zearalenone 분석에 효과적으로 활용할 수 있으리라 생각된다.

• 한국축산식품학회지
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• 제35권1호
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• pp.71-79
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• 2015

This study was performed to determine the effect of multilayered fish oil (FO) emulsion without or with trans-cinnamal-dehyde on pork patties. Multilayered FO (-primary, -secondary, -tertiary) emulsions were prepared using a layer-by-layer deposition technique with Tween 20, chitosan, and low methoxyl pectin, and were added to pork patties at the same concentration. Pork patties were then stored for 20 d in a refrigerator ($5^{\circ}C$) to study changes in quality. The results showed that the pH value of all samples significantly decreased but cooking loss increased during storage (p<0.05). However, water-holding capacity and moisture content showed no remarkable difference between treatments and storage periods (p>0.05). All pork patties containing multilayered FO (treated samples) showed higher values for lightness and significantly lower values for yellowness compared to control pork patties (untreated sample). Lipid oxidation was higher in treated pork patties than in control pork patties during storage. In addition, lipid oxidation and total viable bacterial count in pork patties decreased as the number of coating layers increased. However, hardness, cohesiveness, and springiness of all samples showed no significant change during storage (p>0.05) as compared to fresh pork patties. Furthermore, these did not remarkable change with addition of trans-cinnamaldehyde in all pork patties. From our results, we suggest that FO emulsion did not affect the texture characteristics of fresh pork patties, indicating that it could be used to improve the quality of pork patties by contributing high-quality fat such as unsaturated fatty acids.

• 마이크로전자및패키징학회지
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• 제17권3호
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• pp.71-77
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• 2010

마그네슘 합금은 낮은 밀도를 가지는 장점을 이용하여 자동차, 항공, 이동전화, 컴퓨터 등에 많이 쓰이고 있으나 기계적 강도가 낮고 내부식성이 좋지 않아 사용이 제한되었다. 마그네슘 합금 표면에 내식성 산화층을 형성하기 위하여 환경 친화적인 전해 플라즈마 산화법(PEO)을 연구에 사용하였다, PEO법은 수용약 중에서 플라즈마를 발생시켜 전기화학적 산화막을 형성시키는 방법이다. 인가전압과 전휴가 산화피마에 미치는 영향에 대하여 고찰하였다, 또한, 직류와 펄스전류를 사용하여 결과를 분석하였다. 펄스전류를 사용하고 정전류법을 사용한 경우에 치밀한 산화막을 얻을 수 있었다, 부식특성 분석을 위하여 양극산화분극방법을 이용하였다. 표면의 강도는 처리전의 AZ9ID에 비하여 5배 이상 증가하였다.

• 한국전산유체공학회지
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• 제18권1호
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• pp.63-68
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• 2013

The purpose of this study is to investigate the cooling performance of radial heat sink used for high power LED lightings by natural convection cooling with surrounding air. Experimental and numerical analyses are carried out together. Parametric studies are performed to compare the effects of geometric parameters in radial heat sink such as the number of fins, fin height, fin length, and thickness of fin base as well as the surface coatings of radial heat sink. In this study, the cooling of 60 W LED lamp is examined with radiative heat transfer considered as well as natural convection. Numerical results show the optimum condition when the number of fin is 40, heat sink height is 120 mm, fin length is 15 mm, and fin base thickness is 3 mm. The difference in temperature of the LED metal PCB is within $1^{\circ}C$ between numerical analyses and experimental results. Also, the CNT coating on the heat sink surface is found to increase the cooling performance significantly.

• Restorative Dentistry and Endodontics
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• 제14권1호
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• pp.57-70
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• 1989

The purpose of this study was to investigate the effect of salivary gland on the calcification of dentin in rats. 80 Sprague-Dawley male rats that weighed approximately 120gm were used in this study. 5 rats among them were shared as controls. 75 rats received sialoadenectomy were divided into submaxillary adenectomy group, parotidectomy group, and submaxillary-parotid gland combined removal group. In experimental groups, 25 rats in each of the 3 groups were sacrificed at the following intervals; 3 days, 1, 2, 3 and 4 weeks. All animals were sacrificed by vascular perfusion with 10% formalin. The maxillary incisors including periapical tissues were removed and defatted in 20% KOH solution at $0^{\circ}C$ for 24 hours, and dehydrated with acetone. Each tooth specimen was attached on the stab for scanning electron microscopic study. Gold was coated on the each specimen in the thickness of 300${\AA}$ at D.C. 1400V, 6mA for 6 minutes with coating machine (Eiko IB-3). Inner dentinal surfaces of the specimens were observed with SEM (Hitachi S-450). The results were as follows, 1. Parotidectomy groups were found to be inhibited the formation of dentinal calcification compared to submaxillary adenectomy groups in the eady stages. 2. Combined removal of submaxillary and parotid gland was appeared to cause more severe inhibition effect on the dentinal calcification than that of each salivary gland separately. 3. Inhibition of the calcification and mineralization of dentin caused by sialoadenectomy was more extreme from 3 day to 2 weeks after beginning of the experiments. However it was tended to be normalized after that. 4. Salivary gland was responsible for alterations in calcification and mineralization of dentinal growth.

• 한국재료학회지
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• 제13권9호
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• pp.587-592
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• 2003

The thin films of 316L stainless steel were made on glass and S45C substrate by Ion beam assisted deposition with reactive atmosphere of argon and nitrogen. The films were deposited at the various conditions of ion beam power and the ratios of Ar/$N_2$gas. Properties of these films were analyzed by glancing x-ray diffraction method(GXRD), AES, potentiodynamic test, and salt spray test. The results of GXRD showed that austenite phase could be appeared by $N_2$ion beam treatment and the amount of austenite phase increased with the amount of nitrogen gas. The films without plasma ion source treatment had the weak diffraction peak of ferrite phase. But under the Ar plasma ion beam treatment, the strong diffraction peaks of ferrite phase were appeared and the grain size was increased from 12 to 16 nm. Potentiodynamic polarization test and salt spray test indicated that the corrosion properties of the STS 316L films with nitrogen ion source treatment were better than bulk STS 316L steel and STS 316L films with Ar ion source treatment.

• 한국재료학회지
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• 제13권6호
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• pp.389-393
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• 2003

The effect of antireflection layer on the reduction of optical loss has been investigated in Si photodiodes detecting red light with central wavelength of 670 nm. The theoretical analysis showed minimum reflection loss of 6% for the $SiO_2$thickness of about $1100∼1200\AA$ in the $SiO_2$-Si system with the single antireflection layer and no reflection loss for the X$N_3$N$_4$$SiO_2$thickness of $2000\AA$/$1200\AA$ in the $Si_3$$N_4$$SiO_2$-Si system with double antireflection layer. In our experiments, Si photodiodes with the web-patterned $p^{＋}$-shallow diffusion region were fabricated by bipolar IC process technology and the devices were classified into three kinds according to the structure of $Si_3$$N_4$/$SiO_2$antireflection layer. The fabricated devices showed maximum spectral response in the optical spectrum of 650∼700 nm. The average photocurrents of the devices with the $Si_3$$N_4$$SiO_2$thickness of $1000\AA$/X$SiO\AA$, and $2000\AA$$1800\AA$ under the incident power, of -17 dBm were 3.2 uA, 3.5 uA and 3.1 uA, respectively.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.300-300
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• 2014

해양환경 하에서 대형 강구조물의 경우 장기간 부식손상을 방지하기 위해 아크 용사코팅 기술이 오래전부터 유용하게 이용되어 왔다. 아크 용사코팅 기술은 타 용사코팅 기술에 비해 경제성과 생산성이 뛰어나 대형 강구조물에 적용되고 있다. 용사재료로는 Al, Zn 또는 그 합금들이 주로 사용되어 강재에 대해 희생양극 방식효과를 나타낸다. 그러나 아크용사에 의해 적층된 코팅 층은 용사공정 중 불가피하게 수많은 기공과 산화물이 포함되어 내식성 및 내구성에 악영향을 미치게 된다. 따라서 본 연구에서는 알루미늄 합금의 용사코팅 층에 대하여 다양한 후처리를 통해 내식성과 더불어 내구성을 향상시키고자 하였다. 용사코팅은 알루미늄 합금 선재(1.6 ${\varnothing}$)를 사용하여 아크용사를 실시하였다. 용사 시 용사거리는 200 mm, 공기압력은 약 $7kg/cm^2$ 정도로 유지하면서 용사코팅을 실시하여 약 $200{\mu}m$ 두께로 코팅 층을 형성시켰다. 이후 용사코팅 층의 표면에 다양한 후처리재를 적용하였으며, 내구성을 평가하기 위하여 후처리 적용 전후 시험편에 대하여 캐비테이션 실험을 실시하였다. 캐비테이션 실험은 ASTM G32-92에 의거하여 주파수 20 kHz의 초음파 진동 장치(ultrasonic vibratory device)를 사용하였다. 그리고 시험편 표면과 발진 혼에 부착된 팁(tip)과의 거리는 1 mm로 일정하게 유지시킨 뒤, 캐비테이션 발생 시간을 변수로 하여 실험을 실시하였다. 손상된 용사코팅 층의 표면은 주사전자현미경과 광학현미경으로 관찰하였으며, 시험편 손상깊이는 3D 현미경으로 비교 분석하였다. 또한 캐비테이션 실험 전후의 무게를 측정하여 무게 감소량을 상호 비교하였다. 그리고 전기화학적 실험은 천연해수 속에서 자체 제작한 홀더(holder)를 이용하여 $0.33183cm^2$의 용사코팅 층만을 노출시켜 실시하였다. 그리고 기준전극은 은/염화은 전극을, 대극은 백금전극을 사용하였다. 분극실험을 통해 후처리 적용에 따른 용사코팅 층의 부식전위 및 부식전류밀도를 비교 평가하였다. 그 결과, 용사코팅 층에 의하여 강재에 대한 희생양극 방식전위가 확보되었으며, 후처리재가 적용된 용사코팅 층에서 내식성 및 캐비테이션 저항성이 향상되었다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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• pp.16-16
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• 2012

Mg and its alloys have been of great interest because of their low density of 1.7, 30% lighter than Al, but their wide applications have been limited because of their poor resistances against corrosion and/or abrasion. Corrosion resistance of Mg alloys can be improved by formation of anodic films using anodic oxidation method in aqueous electrolytes. Plasma electrolytic oxidation (PEO) is one of anodic oxidation methods by which hard anodic films can be formed as a result of micro-arc generation under high electric field. PEO method utilize not only substrate elements but also chemical components in electrolytes to form anodic films on Mg alloys. PEO films formed on AM50 magnesium alloy in an acidic fluozirconate electrolyte were observed to consist of mainly $ZrO_2$ and $MgF_2$. Liu et al reported that PEO coating on AM30 Mg alloy consists of $MgF_2$-rich outer porous layer and an MgO-rich dense inner layer. PEO films prepared on ACM522 Mg die-casting alloy in an aqueous phosphate solution were also reported to be composed of monoclinic $Mg_3(PO_4)_2$. $CeO_2$-incorporated PEO coatings were also reported to be formed on AZ31 Mg alloys in $CeO_2$ particle-containing $Na_2SiO_3$-based electrolytes. Magnesium tin hydroxide ($MgSn(OH)_6$) was also produced on AZ91D alloy by PEO process in stannate-containing electrolyte. Effects of $OH^-$, $F^-$, $PO{_4}^{3-}$ and $SiO{_3}^{2-}$ ions and alloying elements of Al and Sn on the formation of PEO films on pure Mg and Mg alloys and their protective properties against corrosion have been investigated in this work. $PO{_4}^{3-}$, $F^-$ and $SiO{_3}^{2-}$ ions were observed to contribute to the formation of PEO films but $OH^-$ ions were found to break down the surface films under high electric field. The effect of pulse current on the formation of PEO films will be also reported.

• Korean Chemical Engineering Research
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• 제49권4호
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• pp.498-504
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• 2011

본 연구는 폴리이미드와 폴리이서설폰 중공사막을 이용하여 매립가스의 메탄 회수를 위한 메탄과 질소에 대한 투과도와 선택도를 실험하였다. 폴리이미드와 폴리이서설폰 소재를 건/습식 상전이 법을 이용하여 중공사 형태로 제조하고 표면 실리콘 코팅 후 모듈을 제조하였다. 전자주사 현미경 관찰을 이용하여 제조된 중공사 막의 구조가 치밀한 표면과 망상구조의 비대칭으로 형성된 것을 확인하였다. 압력과 온도가 증가함에 따라 메탄과 질소의 투과도는 증가하였으나 선택도($CH_4/N_2$)는 감소하는 것으로 나타났다. Air gap이 증가할수록 메탄과 질소의 투과도는 감소하였으며 용매치환을 한 중공사막의 투과도는 3.2~7.0배 증가하였다.