• KSBB Journal
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• v.18 no.2
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• pp.117-121
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• 2003

The study was carried out to determine the effect of storage property and qualities on soybean sauce and paste by adding different amount of pyroligneous liquor obtained by sujpercritical fluid extraction(SFE). Purified pyroligneous liquor obtained by SFE at 4$0^{\circ}C$/110 bar contained p-cresol, o-cresol and m-cresol food sterilizers, but no toxic substances such as tar, scorched, furfuraland and monophenol. Thus pyroligneous liquor was considered to be suitable as natural food preservative. In case of soybean sauce, pyroligneous liquor was tested to determine the potential of natual food preservative to prevent flim formation on soybean ksauce 15days at 3$0^{\circ}C$. Increasing amounts of purified pyroligneous liquor added to soybean sauce prevented film forming yeasts. In case of paste, pyroligneous liquor was tested to determine the potential of natural food preservative to inhibit browning on paste 60 days at 3$0^{\circ}C$. Purified pyroligneous liquor added to paste inhibited brown pigment. As a result, purified pyroligneous liquor offered a promising way of improving the quality and storage property of soybean sauce and paste.

• Journal of Radiation Protection and Research
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• v.2 no.1
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• pp.1-8
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• 1977

A base of photographic posi-film which is commecially available has been found to be a possible alpha-particle track detector. Its neutron dosimetric characteristics, i. e., alpha-particle track registrating efficiency and optimum condition of track formation by chemical etching, have been determined experimentally. The range of neutron fluence and dose capable of being measured by a neutron dosimeter consisting of alpha-particle radiator foils $(^{10}B\;and\;^{27}Al)$ and posi-flim solid state track detector, has been estimated on the basis of experimental results and theoryetical background. This detector seems to be useful for neutron dosimetry because of many favorable properties, i. e., simplicity, cheapness and a wide range of sensitivitiy.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.5
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• pp.103-113
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• 1996

The properties of the deposited film depend on the deposition condition and these, in turn depend critically on the morphology and crystal orientation of the films. Therefore, it is important to clarify the nucleation occurrence and growth stage of the morphology and orientation of the film affected by deposition parameters, e.g. the gas pressure and bias voltage etc. In this work, magnesium thin flims were prepared on cold-rolled steel substrates by a thermo-eletron activation ion plating technique. The influence of nitrogen gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. The diffraction peaks of magnesium film became less sharp and broadened with the increase of nitrogen gas pressure. With an increase in nitrogen gas pressure, flim morphology changed from colum nar to granular structure, and surface crystal grain-size decreased. The morphology of films depended not only on gas pressure but also on bias voltage, i.e., the effect of increasing bias voltage was similar to that of decreasing gas pressure. The effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. Magnesium, in general, has not a good corrosion resistance in all environments. However, these magnesium films prepared by changing nitrogen gas pressure showed good corrosion resistance. Among the films, magnesium films which exhibited granular structure had the highest corrosion resistance. The above phenomena can be explained by applying the effects of adsorption, occlusion and ion sputter of nitrogen gas.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.104-107
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• 2001

The fabricated La-modified lead titanate (PLT) thin flim without paling treatment was investigated for modulation frequency dependence of pyroelectric properties by the dynamic method. $Pb_{1-x}La_{x}Ti_{1-x/4}O_{3}$ PLT (x=0.1) thin film having 10 mol% La content was deposited on a $Pt/TiO_{x}/SiO_{2}/Si$ substrate by sol-gel method. The PLT(10) thin film exhibits a relatively excellent dielectric property. The pyroelectric coefficient (p) of the PLT(10) thin film is $6.6{\times}10^{-9}C/cm_{2}\cdot K$ without frequency dependence. The figure of merits for the voltage responsivity and specific detectivity are $1.03{\times}10^{-11}C\cdot cm/J$ and $1.46\times 10^{-9}C\cdot cm/J$, respectively. The PLT(10) thin film has voltage responsivity (Rv) of 5.15 V/W at 8 Hz. Noise equivalent power (NEP) and specific detectivity (D*) of the PLT(10) thin film are$9.93{\times}10^{-8}W/Hz^{1/2}$ and $1.81\times 10^{6}cmHz^{1/2}/W$ at the same frequency of 100 Hz, respectively. The results means that PLT thin film having 10 mol % La content is suitable for the sensing materials of pyroelectric IR sensors.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.12-14
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• 2004

We investigated current limiting characteristics of the flux-lock type high-Tc superconcting fault current limiter(HTSC-FCL) according to fault angles. The Flux-lock type HTSC-FCL consists of primary and the secondary copper coils that are wound in parallel each other through the iron core and YBCO thin flim. In this paper, the current limiting characteristics of the flux-lock type HTSC-FCL according to fault angles in case of the subtractive and additive polarity windings were compared and analyzed. From the results, the flux-lock type HTSC-FCL could limit more quickly fault current as the fault angles increased irrespective of the fault angles. On the other hand, the initial power burden of HTSC element after a fault happened increased as the fault angles increased. In addition, it was confirmed that the resistance of flux-lock type HTSC-FCL in case of subtractive polarity winding was more increased than that of additive polarity winding and that the peak current of fault current in case of subtractive polarity winding was larger than that of the additive polarity winding case.

• Polymer(Korea)
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• v.38 no.5
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• pp.602-612
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• 2014

Polyurethanes containing poly(dimethyl siloxane) (PDMS) unit, PU-Si, were synthesized and their thermal and shape memory properties were investigated. Various amounts of PDMS units were incorporated via a solution polymerization method using mixed diols of poly(tetramethylene ether glycol) (PTMEG) and PDMS-diol as the soft segment (SS) and methylene diphenyl diisocyanate and 1,4-butanediol as the hard segment (HS). Two series of PU-Si samples with an HS content of 23% or 32% were prepared and analyzed. For PU-Si with an HS content of 23%, both the cold crystallization temperature ($T_{cc}$) and melt crystallization temperature of the SS domain moved higher temperature with increasing PDMS content, while the melting temperature ($T_m$) of the SS domain remained unaffected. The increase in HS content from 23% to 32% resulted in the increased $T_m$ and disappearance of $T_{cc}$. The shape recovery of PU-Si flim with an HS content of 32% increased while its shape retention decreased as PDMS content increased.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2536-2538
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• 1998

This paper investigates the residual stress of tetraethoxysilane (TEOS) and 7wt% phosphosilicate glass (PSG), which are commonly used as a sacrificial layer or etch mask in the fabrication of microelectromechanical systems (MEMS). In order to measure residual stress, $2{\mu}m$ thick TEOS and PSG stress measurement structures are fabricated. Polysilicon is used as the sacrificial layer. First the residual stress of an as-deposited 7wt% PSG flim and TEOS film are measured to be-0.3115% and -0.435%, respectively, which are quite large. These films are annealed from $500^{\circ}C$ to $800^{\circ}C$. Annealing has the effects of reducing residual stress. In the case of the 7wt% PSG film, the residual stress becomes +0.00715% after annealing at $625^{\circ}C$ for 150 minutes. In the case of TEOS film, the residual stress reduces to -0.2134% after same condition. Incidentally, this condition is the same condition for depositing a $2{\mu}m$ thick polysilicon at $625^{\circ}C$ at our low pressure chemical vapor deposition (LPCVD) furnace.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.186-186
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• 2013

종래의 흑연 위주 연료전지 분리판 개발되어 최근 고분자 전해질 막 연료전지가 높은 전력, 낮은 배기 가스 배출, 낮은 작동 온도로 자동차 산업에서 상당한 주목을 받고 있다. 요구사항은 높은 전기 전도도, 높은 내식성, 낮은 가스 투과성, 낮은 무게, 쉬운 가공, 낮은 제조비용이다. Thin film Cr 장비로 저항가열 furnace, sputter 등이 사용된다. 연료전지 분리판의 고전도도, 내부식성 보호막의 고속 증착을 위한 새로운 증착원으로 스퍼터 - 승화형 소스의 가능성을 유도 결합 플라즈마에 금속 봉을 직류 바이어스 함으로써 시도하였다. 유도 결합 플라즈마를 이용하여 승화증착 시스템을 사용하여 OES (SQ-2000)와 QMS (CPM-300)를 사용하여 $N_2$ flow에 따른 유도 결합 플라즈마를 이용한 스퍼터-승화증착 시스템을 사용 하여도 균일한 공정을 하는 것을 확인 하였다. 5 mTorr의 Ar 유도 결합 플라즈마를 2.4 MHz, 500 W로 유지하면서 직류 바이어스 전력을 30 W (900 V, 0.02 A) 인가하고, $N_2$의 유량을 0.5, 1.0, 1.5 SCCM로 변화를 주어 특성을 분석하였다. MID (Multiple Ion Detection) mode에서 유도결합 플라즈마를 이용한 스퍼터-승화 증착 장비를 사용하여 CrN thin flim 성장시켰고, deposition rate은 44.8 nm/min으로 얻을 수 있었다. 또한 $N_2$의 유량이 증가할 수록 bias voltage가 증가하는 것을 확인 할 수 있었다. OES time acquisition을 이용한 공정 분석에서는 $N_2$ 유량을 off 하였을 때 Ar, Cr의 중성 intensity peak이 상승하였고, 시간 경과에 따라 sublimation에 의한 영향이 없는 것을 확인 할 수가 있었다. XRD data에서는 질소 유량이 증가함에 따라 $Cr_2N$이 감소하고, CrN이 증가하는 것을 확인할 수가 있었다. 결정배향성과 Morphology는 다결정 재료의 경도에 영향을 주는 인자이다. CrN 결정 구조의 경우는 (200)면이 경도가 제일 높은데 (200)면에서 성장한 것을 확인 할 수 있었다. 잔류가스 분석 결과로는 일정한 Ar의 유량을 흘렸을 때 $N_2$의 변화량이 비례적인 경향이 보이는 것을 확인 할수 있었다. 또한 $N_2$가 흐르면서도 유도 결합 플라즈마를 이용한 스퍼터-승화 증착 시스템을 사용하면 일정한 공정을 하는 것을 확인 할 수 있었다. 질소의 분압이 유량에 따라서 $3.0{\times}10^{-10}$ Torr에서 $1.65{\times}10^{-9} $Torr까지 일정한 비율로 증가한다. 즉, 이 시스템으로 양산장비 설계를 하여도 가능 하다는 것을 말해준다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.185-185
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• 2012

중공 발광 나노 물질은 특유의 구조적 특성(낮은 밀도, 높은 비표면적, 다공성 물질, 낮은 열팽창계수 등)과 광학적 성질을 이용하여 디스플레이 패널, 광결정, 약물전달체, 바이오 이미징 라벨 등의 다양한 적용이 가능하다. 이러한 적용에 있어 균일한 크기와 형태의 중공 입자는 필수 조건으로 여겨진다. 지금까지 합성된 중공 발광 입자에는 BaMgAl10O17 : Eu2+-Nd3+, Gd2O3 : Eu3+, $EuPO_4{\cdot}H_2O$과 같은 것들이 있으나 크기 조절이 어렵고, 그 균일성이 확보되지 못하였다. 균일한 크기의 중공 발광 입자를 만들기 위해 SiO2나 emulsion을 템플릿으로 이용하여 황화카드뮴, 카드뮴 셀레나이드 중공 입자를 합성한 예가 있으나, 양자점의 독성으로 인하여 바이오분야 응용에는 적합하지 않다. YAG는 모체로써 형광체에서 가장 많이 이용되는 물질로, 화학적 안정성과 낮은 독성, 높은 양자 효율 등 많은 장점을 갖고 있다. 특히 세륨이 도핑된 YAG형광체의 경우 WLED, 신틸레이터, 바이오산업에 적용이 가능하다. 그러나 지금까지 중공 YAG:Ce3+형광체를 합성한 예가 없었다. 본 연구에서는 단분산 수화 알루미늄 (Al(OH)3) 입자 위에 세륨이 도핑 된 이트륨 베이직 카보네이트 ($Y(OH)CO_3$)를 균일하게 코팅한 후 열처리를 하여 균일한 크기의 Y3Al5O12:Ce3+(YAG) 중공 입자를 합성하였다. 열처리 온도에 따른 고분해능 투과 전자 현미경(HRTEM), X-선 회절(XRD), 고분해능 에너지 분광법(HREDX) 분석결과, 중공 YAG: Ce3+입자는 Kirkendall 효과에 의해 형성됨을 확인하였다. 전계방사형 주사 전자 현미경(FE-SEM) 측정을 통해, 열처리 후에도 입자의 크기와 형태가 균일함을 확인하였으며, 공초점 현미경 관찰을 통해 중공 형태를 명확히 확인 할 수 있었다. Photoluminescence (PL) 분광법과 형광 수명 이미징 현미경(FLIM)을 이용한 광 특성 분석결과, 합성된 입자는 400-500 nm에서 흡수 파장 (456 nm에서 최대 강도)과 500-700 nm 범위의 발광 파장(544 nm에서 최대 강도)을 나타냈고, 상용 YAG: Ce3+(70 ns)에 준하는 74 ns의 잔광 시간(decay time)이 측정되었다. 단분산 수화 알루미늄 입자의 크기를 조절하여 최종 합성된 YAG: Ce3+의 크기를 조절할 수 있었다. 지름 약 600 nm의 Al(OH)3를 사용한 경우, $1,300^{\circ}C$에서 열처리를 한 후 평균 지름 590 nm의 중공입자를 합성하였고, 약 170 nm의 Al(OH)3를 이용하여, 더 낮은 온도인 $1,100^{\circ}C$에서의 열처리를 통해 평균지름 140 nm의 중공 YAG: Ce3+입자를 합성하였다. 본 연구를 통하여 합성된 균일한 크기의 YAG 중공입자는 LED와 같은 광전변환 소자 및 다기능성 바이오 이미징 등의 나노바이오 소자 분야에 활용될 수 있음이 기대된다.

• Research in Plant Disease
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• v.8 no.3
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• pp.179-183
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• 2002

to investigate occurrence of kiwifruit bacterial canker disease,172 kiwifmit orchards in Jeonnam and Gyeong-nam provinces were surveyed from March to April in 1999. In the south coast region of Korea, such as Haenam, Wando, Jindo, Jangheung, and Bosuns, red-rusty brown bacterial oozes were observed in 17 kiwifvuit orchards. Disease incidences varied from 2.2% to 100% depending on various regions. Total 22.8 ha of kiwifruit orchards were destroyed by occurrence backerial canker at 1999 in Korea. Orchard in Wando, Jindo, and Goheng were severely damaged in 1999. The seasonal variation of bacterial canker incidence was also investigated from 1996 to 1997 on leaves, vines and twigs of kiwifruit. Red-rusty brown bacterial ooze was exuded from mid February or early March to late April in creaked site of vine and twig. The seasonal incidence of bacterial canker on leaves appeared from late April to late June, and rapidly increased during May, Optimum growth temperature of Pseudomonas sytingae pv. actinidiae was at $25^{\circ}C$ on King's B medium and did not grow at 33$^{\circ}C$. We suggest that spreading of bacterial canker was suppressed under the plastic flim and windbreak net house.