• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.17-17
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• 2009

We report the invention of a direct growth method termed On-Film Formation of Nanowire (OFF-ON) for making high-quality single-crystal nanowires, i.e. Bi and $Bi_2Te_3$, without the use of conventional templates, catalysts, or starting materials. We have used the OFF-ON technique to grow single crystal semi-metallic Bi and compound semiconductor $Bi_2Te_3$ nanowires from sputtered Bi and BiTe films after thermal annealing, respectively. The mechanism for nanowire growth is stress-induced mass flow along grain boundaries in the polycrystalline films. OFF-ON is a simple but powerful method for growing perfect single-crystal semi-metallic and compound semiconductor nanowires of high aspect ratio with high crystallinity that distinguishes it from other competitive growth approaches that have been developed to date. Our results suggest that Bi and $Bi_2Te_3$ nanowires grown by OFF-ON can be an ideal material system for exploring their unique thermoelectric properties due to their high-quality single crystalline and high conductivity, which have consequence and relevance for high-efficiency thermoelectric devices.

• 한국재료학회지
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• 제33권3호
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• pp.95-100
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• 2023

This research examines the effect of adding aluminum on the structural, phasic, and magnetic properties of CoCrFe NiMnAl_x high-entropy alloys. To this aim, the arc-melt process was used under an argon atmosphere for preparing cast samples. The phasic, structural, and magnetic properties of the samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrational magnetometry (VSM) analyses. Based on the results, the addition of aluminum to the compound caused changes in the crystalline structure, from FCC solid solution in the CoCrFeNiMn sample to CoCrFeNiMnAl BBC solid solution. It was associated with changes in the magnetic property of CoCrFeNiMnAl_x high-entropy alloys, from paramagnetic to ferromagnetic. The maximum saturation magnetization for the CoCrFeNiMnAl casting sample was estimated to be around 79 emu/g. Despite the phase stability of the FCC solid solution with temperature, the solid solution phase formed in the CrCrFeNiMnAl high-entropy compound was not stable, and changed into FCC solid solution with temperature elevation, causing a reduction in saturation magnetization to about 7 emu/g.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.650-653
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• 2004

We have synthesized some phosphors in the system MO-$Al_2O_3-SiO_2$(M=Sr, Ba) by combinatorial polymerized-complex method. Composition and synthetic temperature of phosphors in the liblary was screened from the emission intensities of individual samples under 365nm excitation. As we were screened the higher luminescent candidate composition (or candidate host lattice) at 365nm excitation, investigated whether good radiation was possible at the 405 or 465nm excitation by give the host lattice to be discovered more various change. From libraries about 2 systems, the compound to be expected in long wavelength among the compound to be screened are $Sr_4Al_{14}O_{25}$, $Sr_3Al_2O_6$, $SrAl_2Si_2O_8$, and $BaAl_2Si_2O_8$.

• 마이크로전자및패키징학회지
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• 제17권3호
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• pp.59-63
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• 2010

Immersion Sn plating was produced on Cu foil by distributing nano-sized diamonds (ND). The ND distributed on the coating surface broke the continuity of Sn-oxide layer, therefore leading to penetrate the molten solder through the oxide and retarding the wettability degradation during a reflow process. Furthermore, the ND in the Sn coating played a role of diffusion barrier for Sn atoms and decreased the growth rate of intermetallic compound ($Cu_6Sn_5$) layer during the solid-state aging. The study confirmed the importance of ND to improve the wettability and reliability of the Sn plating. Complete dispersion of the ND within the immersion Sn plating needs to be further developed for the electronic packaging applications.

• 한국염색가공학회지
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• 제8권4호
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• pp.11-18
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• 1996

Natural functional compound in the textile finishing for health and amenity using fragrant material have been applied by microencapsulation method. The microcapsules containing fragrant materials as functional compound were produced by in situ polymerization using urea-formaldehyde prepolymer. The average diameter of microcapsules is 2.75$\mu$ and particle size ranges over 0.5~10$\mu$. Fragment material is extracted approximatly proportioned from microcapsule at room temperature. The adsorption of microcapsule was improved by pretreatment of cationic agent. Fragrant materials in microcapsule was revealed to have long release time.

• 한국염색가공학회지
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• 제18권2호
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• pp.24-30
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• 2006

The photosensitive spiroxazine compound and the electrosensitive viologen compound were prepared to examine their practical application feasibilities and behaviors. These dyes represent corresponding chromism effects related to their own characteristics of the dye molecules. Thus, the prepared dyes were characterized and their absorption spectra were also investigated. Besides, an interest on direct spiroxazine exhaustion to the polyamide substrates and its photochromic effects within the fiber molecules were determined. The photochromic reaction on the substrates was clearly observed and its reversible decoloration behaviors responded.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.223-223
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• 2007

Thermal and mechanical properties were investigated in several semi-conductive materials which is composed of carbon black and polymer. EVA, EEA, and EBA is normally used for matrix polymer and normally acetylene black and furnace black is used. Isothermal thermo gravimetric analysis is done as a function of atmosphere and temperature. In nitrogen atmosphere semicon compound was slowly degradaded but in ambient condition degradaded fast. So in the cable manufacturing, atmosphere and materials are very important.

• 한국재료학회지
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• 제18권3호
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• pp.153-158
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• 2008

Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of $700\;{\mu}m$ was formed by a heat treatment at $665^{\circ}C$ for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.

• 한국응용과학기술학회지
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• 제38권5호
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• pp.1335-1344
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• 2021

진세노사이드 Compound K는 트라이터펜계 사포닌으로써 인삼의 잎, 줄기, 뿌리등에서 발견된다. 본 연구는 효소 Plantase를 이용하여 인삼 추출물로부터 고부가가치의 진세노사이드인 Compound K를 생산하는 연구를 하였다. Plantase는 인삼추출물에서 Compound K를 매우 효율적으로 생산함을 보여 주었다. 또한 다양한 온도와 pH에서 Compound K 생산에 대한 최적의 반응을 조사한 결과 pH 5, 50 ℃에서 가장 높은 효율을 보였다. 최적 조건에서 Compound K는 전체 추출물의 35%이상 농축될 수 있음을 확인하였다. 생물전환된 Compound K 농축물의 항균효과를 검정한 결과 여드름균인 Cutibacterium acnes KCTC 3314에 선택적인 활성을 보였다. Compound K (35% 함유) 인삼 생물전환물의 C. acnes KCTC 3314 균주에 대한 최소저해농도 측정 결과 31.25ug/mL로 확인되었다. 따라서 향후 여드름균 완화용 화장품의 잠재적 소재로 사용될 수 있을 것으로 기대된다.

• 한국연초학회지
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• 제2권1호
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• pp.8-16
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• 1980

Zeolite의 일종인 clinoptilolite를 담배필터 첨가제로 활용하는 연구를 하였다. 입자크기 30 $\pm$ 5 A.S.T.M. mesh의 clinoptilolite와 charcoal 1 : 1 (V/V)로 혼합하여 삼중필터의 cavity부분에 충진했을 때, 1. Cellulose acetate필터에 비하여 nicotine 35%, T.P..M.22%를 감소시켰으며, 2. Gas phase중 n-amyl alcohol등 aliphatic compound와 furan등 cyclic compound를 cellulose acetate filter에 비하여 60$\pm$ 5%를 감소시켰다. 3. Charcoal의 removal efficiency는 40-50% clinoptilolite의 10-20%에 비하여 큰 값이였지만 charcoal은 분자량이 큰 aromatic compound의 removal efficiency가 50$\pm$5%로서 aliphatic compound의 removal efficiency 40: 5%보다 큰 값이였음에 비하여 clinoptilolite는 alcohol과 ketone계열의 분자갹이 작은 화합물의 removal efficiency가 15-20%로 cyclic compounds의 removal efficiency 10-15%에 비하여 보다 큰 값이었다. 이 두물질의 gas phase성분의 흡착기능은 상호 보완적임을 알 수 있었다.