• Proceedings of the Korean Vacuum Society Conference
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• 1995.02a
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• pp.057-58
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• 1995

극소전자 디바이스의 고집적화에 의해 박막배선의 선폭은 0.5$mu extrm{m}$ 이하로 축소되고 있고 상대적으로 높은 전류밀도가 흐르게 된다. 높은 전류밀도하에서는 현재 일반적으로 사용되고 있는 Al을 기본으로 하는 박막배선에서의 electromigration에 의한 결함 발생 그리고 비교적 낮은 전기전도도가 심각한 문제점으로 제기된다. 본 연구에서는 Al과 고전기전도도 물질인 Ag, Cu, 그리고 Au 박막배선에 대해 electromigration에 대한 저항성, 즉 activation energy를 측정 비교함으로써 차세대 극소전자 디바이스를 위한 박막배선재료로서의 가능성을 알아보고자 한다. Electromigration test 및 activation energy를 구하기 위해 순수 Ag, Cu, Al, Au 박막배선을 0.05$\mu\textrm{m}$ 두께, 100$\mu\textrm{m}$ 선폭, 그리고 5000$\mu\textrm{m}$ 길이로 SiO2 열산화막 처리된 pp-Si(100) 기판 위에 진공 증착시켰다. 가속화 실험을 위해 인가된 d.c. 전류밀도는 2$\times$106A/$ extrm{cm}^2$ 이었고, Al과 Au에서는 6$\times$106A/$\textrm{cm}^2$이었다. 실온에서 24$0^{\circ}C$까지의 온도범위에서 d.c.인가후의 저항변화를 측정하여 Median-Time-to-Failure(MTF)를 구한 후 Black 방정식을 이용하여 activation energy를 측정하였다. Activation energy는 Cu가 1.34eV로서 가장 높게 나타났고 Au가 1.01eV, Al이 0.66eV, Ag가 0.29eV의 순으로 측정되었다. 따라서 Cu와 Au 박막배선의 경우 Al보다 electromigration에 대한 저항력이 강한 고활성화에너지 특성을 갖는 고전기전도도 재료로서 차세대 극소전자 디바이스를 위한 대체 박막배선재료로서의 가능성을 보인다.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.39-46
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• 1995

This study was carried out to investigate antibacterial activities of the green tea extract according to storage temperature as death velocity constant. The survey data were collected from seven green teas (2 Korean, 2 Japanese, 2 Chinease and 1 Vietnamese) and experimental strains were used E. coli No. 11234, Ent. aerogenes No. 11783, Ps. fiu. orescens No. 11210, S. marscens No. 11808, St. mutans No. 11823 and V. parahaernolyticus No. 11965. The experimental results obtained were as follows: 1. Antibacterial activities of the green tea extracts according to the strains were strikingly difference. That is, those of the samples appeared to be conspicuous on [St. mutans No. 11823 (Range of death velocity constant a day after, at 20$\circ$C 4.85~5.22) and V. parahaemolyticus No. 11965 (4.70~6.00) while E. coli No. 11234 (0.59~-0.30) and Ent. aerogenes No. 11783 (0.24~-0.11)] were not so. 2. To storage temperature at 5$\circ$C than that at 20$\circ$C, antibacterial activities of the green tea extract on Ps. fluorescens No. 11210, S. marscens No. 11808, E. coli No. 11234, and Ent. aerogenes No. 11783 were sensitived but St. mutans No. 11823 and V. parahaemolyticus No. 11965 were not related to those. 3. Antibacterial activities to the strains were increased within two days.

• Journal of Korea Foundry Society
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• v.20 no.4
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• pp.260-268
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• 2000

응고 및 마모거동을 연구하기 위하여 Cr, V, Mo 및 W의 조성이 다른 3종류의 백주철을 주조하였다. 고주파유도용해로에서 장입시켜 1873K까지 승온시켜 장입원료들을 모두 용해시킨 후 1823K에서 Y블럭주형에 주입하였다. 얻어진 3종류의 백주철조성은 다음과 같다: Fe-3%C-10%Cr-5%Mo-5%W(합금1), Fe-3%C-10%V-5%Mo-5%W(합금2) 및 Fe-3%C-17%Cr-3%V(합금 3)응고과정을 추적하기 위하여 각 시편으로부터 50g을 채취한 후 알루미나도가니에 넣고 실리콘카바이드로를 사용하여 1723K의 알콘분위기하에서 재용해를 시켰다. 용금을 10K/분의 속도로 냉각시키면서 열분석을 행하였으며 도중 몇 차례 소입 실험을 병행하였다.합금1의 경우 초정오스테나이트, (오스테나이트+$M_7C_3$)공정, (오스테나이트+$M_6C$)공정, 합금2의 경우 초정 MC, 초정오스테나이트, (오스테나이트+MC)공정 , (오스테나이트+$M_2C$)공정, 합금3의 경우 초정 $M7C_3$와 (오스테나이트+$M_7C_3$)공정으로 구성되어 있었다. 주방상태, 균질화열처러상태, 공냉상태, 템퍼링상태에서 내마모시험을 행하였다. 먼저 주방상태시 편을 진공분위기하에서 1223K에서 5시간동안 균질화열처리를 행한후 로냉을 시켰다. 다시 이 시편을 1323K에서 2시간 유지후 강제공냉을 시켰으며 강제공냉된 시편을 573K에서 3시간동안 템퍼링처리를 하였다. 내마모시험은 120 mesh마모지에 10N의 하중을 가하여 실시하였다. 각 사이클마다 무게감소를 측정하였으며 8번 반복실험을 하였다. 마모량은 균질화열처리시편, 주방상태시편, 템퍼링시편, 공냉시편의 순으로 감소하였다. 합금2가 마모량이 가장 적었으며 합금3이 가장 많았다. 합금2의 마모량이 가장 적은 이유는 조직이 초정 MC, 공정 MC 및 공정 M2C로 구성되어 있기 때문으로 사료된다.주방상태에서 기지조직은 퍼얼라이트이었으나 열처리를 통하여 마르텐사이트, 템퍼드마르텐사이트, 잔류오스테나이트로 변태하였다. 이상의 결과를 종합해 보면 MC가 내마모성에 가장 기여하는 조직으로 판단되어진다.

• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.44-48
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• 2000

Amorphous $V_2O_5$ cathode thin films were prepared by DC-magnetron sputtering at room temperature and the thin film rechargeable lithium batteries were fabricated with the configuration of $V_2O_5/LIPON/Li$ using sequential ex-situ thin film deposition techniques. The electrochemical characteristics of $V_2O_5$ cathode materials Prepared at 80/20 of $Ar/O_2$ ratio showed high capacity and cycling behaviors by half cell test. LIPON solid electrolytes films were prepared by RF-magnetron sputtering using the self-made $Li_3PO_4$ target in pure $N_2$ atmosphere, and it was very stable for lithium contact in the range of 1.2-4.0 V vs. Li. Metallic lithium were deposited on LIPON electrolyte by thermal evaporation methode in dry room. Vanadium oxide based full cell system showed the initial discharge capacity of $150{\mu}A/cm^2{\mu}m$ in the range of $1.2\~3.5V$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.12
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• pp.936-941
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• 2010

In this study, we have investigated the effects of Mn dopant on the bulk trap levels and grain boundary characteristics of $Bi_2O_3$-based ZnO (ZB) varistor using admittance spectroscopy and dielectric functions (such as $Z^*,\;Y^*,\;M^*,\;\varepsilon^*$, and $tan\delta$). Admittance spectra and dielectric functions show two bulk traps of $Zn_i^{..}$ (0.20 eV) and $V^{\bullet}_o$ (0.29~0.33 eV) in ZnO-$Bi_2O_3-Mn_3O_4$ (ZBM). The barrier of grain boundaries in ZBM could be electrochemically single type. However, its thermal stability was slightly disturbed by ambient oxygen because the apparent activation energy of grain boundaries was changed from 0.79 eV at lower temperature to 1.08 eV at higher temperature. The grain boundary capacitance $C_{gb}$ was decreased slightly with temperature as 1.3~1.8 nF but resistance $R_{gb}$ decreased exponentially. The relaxation time distribution can result from the heterogeneity of the barriers constituting the varistor. It is revealed that Mn dopant in ZB reduced the heterogeneity of the barrier in grain boundaries and stabilized the barrier against the ambient temperature.

• Korean Journal of Microbiology
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• v.38 no.4
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• pp.281-286
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• 2002

Detection of Vibrio vulnificus in fish farm and searching for the bactericidal methods on this bacteria were studied. To detect this microorganism in sea water, mud, fish and mussels, selective isolation methods and detection of vvhA gene were used from January to October,2000. V. vulnificus was detected from May when the water temperature was over $17^{\circ}C$. From June to September, higher than $19^{\circ}C$, this bacteria could be isolated from most of the samples. Freezing and refrigerating did not inhibit the growth of V. vulnificus. Citric acid did not show the bactericidal effect, but more than 500 mg/l of EDTA did. With the aid of UV and photocatalyst, $TiO_{2}$ showed bactericidal effect after 15 minute treatment. Photocatalytic system consisted of glass bead coated with $TiO_{2}$ and UV illumination showed bactericidal effect on V. vulnificus at the turnover rate of 0.2/min.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.277-288
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• 2017

Rhizomucor miehei NRRL 5282 and Rhizopus oryzae NRRL 1526 can produce lipases with high synthetic activities in wheat bran-based solid-state culture. In this study, the purification and biochemical characterization of the lipolytic activities of these lipases are presented. SDS-PAGE indicated a molecular mass of about 55 and 35 kDa for the purified R. miehei and Rh. oryzae enzymes, respectively. p-Nitrophenyl palmitate (pNPP) hydrolysis was maximal at $40^{\circ}C$ and pH 7.0 for the R. miehei lipase, and at $30^{\circ}C$ and pH 5.2 for the Rh. oryzae enzyme. The enzymes showed almost equal affinity to pNPP, but the $V_{max}$ of the Rh. oryzae lipase was about 1.13 times higher than that determined for R. miehei using the same substrate. For both enzymes, a dramatic loss of activity was observed in the presence of 5 mM $Hg^{2+}$, $Zn^{2+}$, or $Mn^{2+}$, 10 mM N-bromosuccinimide or sodium dodecyl sulfate, and 5-10% (v/v) of hexanol or butanol. At the same time, they proved to be extraordinarily stable in the presence of n-hexane, cyclohexane, n-heptane, and isooctane. Moreover, isopentanol up to 10% (v/v) and propionic acid in 1 mM concentrations increased the pNPP hydrolyzing activity of R. miehei lipase. Both enzymes had 1,3-regioselectivity, and efficiently hydrolyzed p-nitrophenyl (pNP) esters with C8-C16 acids, exhibiting maximum activity towards pNP-caprylate (R. miehei) and pNP-dodecanoate (Rh. oryzae). The purified lipases are promising candidates for various biotechnological applications.

• Journal of Convergence for Information Technology
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• v.7 no.6
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• pp.97-102
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• 2017

In this paper, we have interested in cooperative intelligent transport system and autonomous driving system, and focused on analysis of the characteristics of Cooperative Awareness Message (CAM) and Decentralized Environmental Notification Basis Service (DENM) message, which is key delivery message among cooperative intelligent transport system (C-ITS) characteristics for research objectivity. For research method, we also described V2X communication, and also analyzed the security certificate and header structure of CAM and DENM messages. We described CAM message, which is a message informing the position and status of the vehicle. And the DENM message is presented a message informing an event such as a vehicle accident, and analysis security communication, which is supported services. According to standard analysis result, 186 bits or 275 bits are used. In addition to the security header and the certificate format used for vehicle communication, we have gained the certificate verification procedure for vehicles and PKI characteristics for vehicles. Also We derived the characteristics and transmission capability of the security synchronization pattern required for V2X secure communication. Therefore when it is considered for communication service of DENM and CAM in the C-ITS environment, this paper may be meaningful result.

• Electrical & Electronic Materials
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• v.6 no.6
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• pp.573-581
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• 1993

0.10Pb(Sb$_{1}$2/Sn$_{1}$2/)O$_{3}$-0.25PbTiO$_{3}$-0.65PbZrO$_{3}$ 세라믹을 소결온도 및 시간을 각각 1200-1250[.deg.C]에서 2, 4, 6시간으로 변화시켜 제작하였으며 시편의 소결조건 및 MnO$_{2}$(0~0.30mol%)첨가량에 따른 잡음특성을 관찰하였다. 초전계수 및 전압감도는 1250[.deg.C]에서 2시간 소결시킨 시편에서 각각 3.49x$10^{-8}$[C/$cm^{2}$K], 147[V/W]의 최대값을 나타내었다. 초전형 적외선 검출기의 잡음특성에 있어 증폭기의 전류잡음 .DELTA.V$_{i}$가 총 잡음전압에 대해 지배적인 경향을 나타내었으며 MnO$_{2}$가 0.24[mol%] 첨가된 1250[.deg.C]에서 2시간 소결시킨 시편에서 가장 양호한 pop-corn잡음특성을 나타내었다.다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.439-442
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• 2004

The effects of sintering additives on the low-temperature sintering and microwave dielectric properties of $Mg_4Nb_2O_9$ dielectric ceramics were studied. When $3{\sim}20wt%$ of $0.242Bi_2O_3-0.758V_2O_5$ was added, the sintering temperature decreased from $1100{\sim}1300^{\circ}C$ to $950^{\circ}C$ and high density was obtained. When $Mg_4Nb_2O_9$ was sintered at $950^{\circ}C$ with 10wt% of sintering additive, the microwave dielectric properties of $Q{\times}f_0\;=\;80.035GHz,\;\epsilon_r\;=\;13.3\;and\;\tau_f\;=\;-12.9\;ppm/^{\circ}C$ were obtained.