• 한국전자거래학회지
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• 제19권4호
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• pp.31-43
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• 2014

최근 많은 사이버 공격은 S/W의 취약점을 이용한 익스플로잇(exploit)으로 이루어지고 있다. 주기적으로 취약점 동향이 발표되고 있으며 이를 참고로 보안의 방향이 제시되고 개선 방안도 수정되고 있다. 그럼에도 불구하고 2011년 한 해 동안 발생한 해킹 등 사이버 공격은 2010년 대비 81% 증가하였고, 이러한 사이버 공격의 약 75%가 S/W 자체의 보안 취약점을 악용하고 있다. 본 논문에서는 S/W 취약점으로 인한 손실비용 측정을 위해 질병 전파 모델인 SIR 모델을 응용하여 취약점에 의한 악성코드 감염 확산 모델인 VIR모델을 제시하고, 이를 한글 S/W 취약점에 적용하여 손실비용이 어느 정도인지를 추정하였다.

• 한국분말재료학회지
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• 제10권4호
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• pp.270-274
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• 2003

Recently, the fabrication process of W-Cu nanocomposite powders has been researched to improve the sinterability by mechanochemical process (MCP), which consists of ball milling and hydrogen-reduction with W- and Cu-oxide mixture. However, there are many control variables in this process because the W oxides are hydrogen-reduced via several reduction stages at high temperature over 80$0^{\circ}C$ with susceptive reduction conditions. In this experiment, the W-15 wt%Cu nanocomposite powder was fabricated with the ball-milling and hydrogen-reduction process using W and CuO powder. The microstructure of the fabricated W-Cu nanocomposite powder was homogeneously composed of the fine W particles embedded in the Cu matrix. In the sintering process, the solid state sintering was certainly observed around 85$0^{\circ}C$ at the heating rate of 1$0^{\circ}C$/min. It is considered that the solid state sintering at low temperature range should occur as a result of the sintering of Cu phase between aggregates. The specimen was fully densified over 98% for theoretical density at 120$0^{\circ}C$ for 1 h with the heating rate of 1$0^{\circ}C$/min.

• 한국분말재료학회지
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• 제27권4호
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• pp.293-299
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• 2020

W₂C is synthesized through a reaction-sintering process from an ultrafine-W and WC powder mixture using spark plasma sintering (SPS). The effect of various parameters, such as W:WC molar ratio, sintering temperature, and sintering time, on the synthesis behavior of W₂C is investigated through X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) analysis of the microstructure, and final sintered density. Further, the etching properties of a W₂C specimen are analyzed. A W₂C sintered specimen with a particle size of 2.0 ㎛ and a relative density over 98% could be obtained from a W-WC powder mixture with 55 mol%, after SPS at 1700℃ for 20 min under a pressure of 50 MPa. The sample etching rate is similar to that of SiC. Based on X-ray photoelectron spectroscopy (XPS) analysis, it is confirmed that fluorocarbon-based layers such as C-F and C-F2 with lower etch rates are also formed.

• KSBB Journal
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• 제9권4호
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• pp.436-442
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• 1994

Aspergillus terreus NRRL 1960에 의한 이다콘산의 생산에 관해 연구하였다. pH, 접종량, 배지조성 등의 최적조건을 확립하였다. 이타콘산의 최대생산 량은 37°C, pH 2.5의 조건에셔, 5% (w/v) glu­c cose, 0.5 % (w/v) $NH_4Cl$, 0.2 % (w/v) yeast ex­tract, 0.1 % (w/v) $MgSO_4$, 0.2 % (w/v) NaCI을 포함하는 배지에서 7일만에 $19.18g/\ell$를 얻을 수 있었다. 종균배양 배지로서 2 % malt extract가 적합하였다. 교반식 반응기에서 유리균체에 의한 이타콘 산의 회분식 생산은 플라스크 배양에 비해 비효율적 이었다.

• 생명과학회지
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• 제13권4호
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• pp.498-504
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• 2003

맛버섯( Pholiota nameko KACC50453)의 균사체 배양 특성에 관한 연구 결과 맛버섯 균사체의 배양에 적합한 기본 배지는 ME였으며, 최적 배양 온도는 $25^{\circ}C$, 최적 초기 pH는 5.5였다. 맛버섯 균사체 생장을 위한 최적 배지 조성은 glucose 3%(w/v),malt extrac 0.25%(w/v), yeast extract 0.25%(w/v),$KH_2PO_4$ 0.046%(w/v),$K_2HPO_4$ 0.1%(w/v),$MgSO_4$ $.$$7H_2O$0.05% (w/v)로 나타났다.기본배지(ME)와 최적배지로 액체 배양한 결과 최적 배지에서 균사생장이 양호하였다.

• 약학회지
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• 제39권5호
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• pp.495-505
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• 1995

The O/W microemulsion systems were made from 2 or 4% (w/w) oil (soybean oil, olive oil or isopropyl myristate) and 10, 15 or 20% (w/w) Brij 96. They were compared with micellar solution of equivalent surfactant concentration m therms of physicochemical properties, and the solubilization of sudan IV. They were characterized by dynamic light scattering, stability, surface tension, viscosity and rheogram. The mean diameters of O/W microemulsion systems were 10-15nm, and those of Brij 96 micellar solutions were 18-19 nm. Both of them were monodisperse systems. The O/W microemulsion systems showed Newtonian flow and their apparent viscosities were lower than those of micellar solutions. The surface tensions of O/W microemulsion systems were increased or decreased depending on the types of oil used, when compared with those of micellar solutions. The O/W microemulsion systems were very stable, and did not show any flocculation or aggregation. Their mean diameters were not changed after three months. But oxidation was observed in microemulsions without nitrogen gas at high temperature. There was a significant improvement in the sudan IV solubffimtion in micromulsion compared with that m the micellar solution containing equivalent concentration of surfactant. The size distribution and mean diameters of O/W micromulsions were not changed when sudan IV was solubilized.

• 한국정보통신학회논문지
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• 제12권7호
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• pp.1301-1307
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• 2008

본 논문에서는 ARM 칩인 AT91SAM7S256, UHF RFID R/W 모듈인 WJ7090 및 무선 랜(IEEE 802.11.a/b)을 이용하여 UHF RFID R/W 전용 단말기를 개발하고 그 성능을 개선하였다. 또한 AT91SAM7S2S6에서 UHF R/W 모듈인 WJ7090으로 보내지는 송수신패킷을 개발하였다. 본 논문에서 개발한 무선랜(IEEE 802.11.a/b) 기반의 UHF RFID R/W 전용 단말기의 유용성을 평가하기 위해 성능 테스트를 실시하였다. 본 논문에서 개발한 UHF RFID R/W 전용 단말기는 RFID Tag값을 Tagging하고 그 값을 무선 랜(IEEE 802.11.a/b)을 통해서 서버로 전송하고, 그 결과를 단말기에 표시하였고, 성능실험을 통해 개발한 단말기의 우수성 및 송수신패킷에 대한 실험 결과를 나타내었다.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2801-2808
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• 2022

The synergistic effect of ZrC nanoparticle pining and Re solution in W matrix on the thermal stability of tungsten was studied by investigating the evolution of the microstructure, hardness and tensile properties after annealing in a temperature range of 1000-1700 ℃. The results of metallography, electron backscatter diffraction pattern and Vickers micro-hardness indicate that the rolled W-1wt%Re-0.5 wt% ZrC alloy has a higher recrystallization temperature (1600 ℃-1700 ℃) than that of the rolled pure W (1200 ℃), W-0.5 wt%ZrC (1300 ℃), W-0.5 wt%HfC (1400-1500 ℃) and W-K-3wt%Re alloy fabricated by the same technology. The molecular dynamics simulation results indicated that solution Re atoms in W matrix can slow down the self-diffusion of W atoms and form dragging effect to delay the growth of W grain, moreover, the diffusion coefficient decrease with increasing Re content. In addition, the ZrC nanoparticles can pin the grain boundaries and dislocations effectively, preventing the recrystallization. Therefore, synergistic effect of solid solution Re element and dispersed ZrC nanoparticles significantly increase recrystallization temperature.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1994년도 춘계학술대회강연 및 발표대회 강연및 발표논문 초록집
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• pp.21-21
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• 1994

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2019년도 하계 학술발표초록집
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• pp.104-119
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• 2019