• 한국연초학회지
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• 제27권2호
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• pp.171-177
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• 2005

Coconut based activated carbon and silica-gels were impregnated with 3-aminopropyltri ethoxysilan(APS) and N-(2-aminoethyl)-3-aminopropyl triethoxysilane (AEAPS) in order to investigate the effect of the amine group and the pore size of the supports on the removal of hydrogen cyanide(HCN) and aldehydes in mainstream smoke(MS). The physicochemical properties of the supports were analyzed by using thermal gravity analyzer(TGA), $N_2$ adsorption and desorption isotherms$(BET,\;N_2)$, and SEM-EDS. According to our experimental data, there was no significant difference in the delivery amount of HCN and aldehydes of non-functionalized silica-gels having meso-pores bigger than $20\AA$. In the case of silica-gels functionalized with APS(APS silica-gel), the delivery amounts of hydrogen cyanide(HCN) and aldehydes decreased with the increase of APS concentration. Silica-gel functionalized with AEAPS(AEAPS silica-gel) showed higher removal efficiency than that of APS silica-gels. The delivery amounts of HCN and aldehydes of activated carbon impregnated with APS and AEAPS increased with the increase of the APS and AEAPS concentrations. In accordance with the specific surface area analysis results, APS and AEAPS molecules decreased the specific surface area by blocking the micro-pores of the activated carbon. The volatile organic components removal efficiency by the micro-pores was higher than that of the amine group impregnated into the activated carbon.

• Molecules and Cells
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• 제37권8호
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• pp.628-635
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• 2014

2-(Trimethylammonium) ethyl (R)-3-methoxy-3-oxo-2-stearamidopropyl phosphate [(R)-TEMOSPho], a derivative of an organic chemical identified from a natural product library, promotes highly efficient megakaryopoiesis. Here, we show that (R)-TEMOSPho blocks osteoclast maturation from progenitor cells of hematopoietic origin, as well as blocking the resorptive function of mature osteoclasts. The inhibitory effect of (R)-TEMOSPho on osteoclasts was due to a disruption of the actin cytoskeleton, resulting from impaired downstream signaling of c-Fms, a receptor for macrophage-colony stimulating factor linked to c-Cbl, phosphoinositol-3-kinase (PI3K), Vav3, and Rac1. In addition, (R)-TEMOSPho blocked inflammation-induced bone destruction by reducing the numbers of osteoclasts produced in mice. Thus, (R)-TEMOSPho may represent a promising new class of antiresorptive drugs for the treatment of bone loss associated with increased osteoclast maturation and activity.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.556-556
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• 2012

Transition metal-based organometallic complexes have shown great talents as a catalyst in various reactions. Designing organic molecules and coordinating them to such active centers have been a promising route to control the catalytic natures. Metallocene, which has transition metal atoms sandwiched by aromatic rings, is one of the representative systems for organometallic catalysts. Group 4-based metallocene catalysts have been most commonly used for the production of polyolefins, which have great world-wide markets in the real life. Graphenes and carbon nanotubes (CNTs) were composed of extended $sp^2$ carbon networks, showing high electron mobility as well as have extremely large steric bulkiness relative to metal centers. We were inspired by these characteristics of such carbon-based nano-materials and assumed that they could intimately interact with active centers of metallocene catalysts. We examined this hypothesis and, recently, reported that CNTs dramatically changed catalytic natures of group 4-based catalysts when they formed hybrid systems with such catalysts. In conclusion, we produced hybrid materials composed of group-4 based metallocenes, $Cp_2ZrCl_2$ and $Cp_2TiCl_2$, and carbon-based nano-materials such as RGO and MWCNT. Such hybrids were generated via simple adsorption between Cp rings of metallocenes and graphitic surfaces of graphene/CNT. The hybrids showed interesting catalytic behaviors for ethylene polymerizations. Resulting PEs had significantly increased Mw relative to those produced from free metallocene-based catalytic systems, which are not adsorbed on carbon-based nano-materials. UHMWPEs with extremely high Mw were obtained at low Tp.

• 공업화학
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• 제18권5호
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• pp.506-510
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• 2007

전기적 특성을 가지는 4,4',4''-tris(N-(1-naphthyl)-N-phenylamino)-triphenylamine (1-TNATA)가 유기발광소자(OLED)에서 전극으로 사용되는 ITO (Indium Tin Oxide)와 홀 수송층(Hole Transport Layer, HTL) 사이에 박막으로 진공증착되었다. 분자배열이 잘 되어진 1-TNATA의 경우 ITO와 홀 수송층 사이의 계면에서 생기는 전하주입장벽을 줄임으로 소자의 안정성과 효율을 높여준다. 본 연구에서의 라만 스펙트라(Raman spectra) 분석 결과, 증착된 1-TNATA 박막의 열처리와 증착하는 동안 전자기장 처리에 의해서 박막이 집적되고 분자배열이 이루어짐을 확인하였다. 열처리를 한 경우 1-TNATA 박막으로의 전류 흐름이 25% 증가하였다. 또한, $110^{\circ}C$에서 열처리한 1-TNATA 박막으로 제조된 다층유기발광소자의 전원 효율과 발광효율이 향상되었다. 열처리한 박막이 전자기장으로 처리한 박막에 비해 높은 효율을 나타내었다.

• 공업화학
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• 제4권1호
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• pp.144-152
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• 1993

${\gamma}-Al_2O_3$, ${\alpha}-Al_2O_3$, $SiO_2$, $TiO_2$등에 고정화된 폴리에틸렌글리콜을 $Fe(CO)_5$에 의한 니트로벤젠의 상온 환원반응에 상이동 촉매로 사용하였다. 고정화된 PEG의 몰수는 담체의 비표면적에 따라 증가하였고 PEG/${\gamma}-Al_2O_3$가 가장 좋은 활성을 나타내었다. PEG의 사슬길이가 길고 NaOH 농도가 높을수록 반응속도가 증가하였다. 적외선분광기를 이용하여 반응기구에 대한 고찰도 함께 실시하였으며 폴리에틸렌글리콜 상이동 촉매는 본 반응의 활성물질로 알려진 $HFe(CO)_4{^{-}}$이온의 생성과 이의 유기상으로의 이동을 촉진시키는 것으로 판단되었다.

• 접착 및 계면
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• 제14권2호
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• pp.82-87
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• 2013

본 연구에서는 레졸, 질산철 그리고 트리블럭 공중합체를 이용하여 직접 탄화과정에 의해 자성체 나노입자가 분산된 탄소나노세공체를 합성하였다. 나노세공 마그네타이트/카본($Fe_3O_4$/carbon) 나노복합체는 낮은 마그네타이트 함량(1 wt%)을 가지고 잘 배열된 이차원적 육방체 구조(p6mm)를 보이며, 균일한 세공크기(3.6 nm), 높은 표면적(635 $m^2/g$)과 세공부피(0.48 $cm^3/g$)를 가진다. 작은 입자크기(10.2 nm)를 가지는 마그네타이트 나노입자는 초상자기성(7.7 emu/g)을 보이고 탄소 세공벽 내에 잘 분산되었다. 나노세공 마그네타이트/카본 물질은 최대 995 mg/g의 아이부프로펜 흡착량을 보였다. 또한, 자석을 이용하여 용액과 나노세공 마그네타이트/카본 물질의 분리가 용이하였다. 본 연구에서 제조된 나노복합체는 우수한 아이부프로펜 흡착제로 작용하였다.

• 설비공학논문집
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• 제20권4호
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• pp.266-273
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• 2008

Natural gas hydrates are ice-like solid substances, which are composed of water and natural gas, mainly methane. They have three kinds of crystal structures of five polyhedra formed by hydrogen-bonded water molecules, and are stable at high pressures and low temperatures. They contain large amounts of organic carbon and widely occur in deep oceans and permafrost regions. Therefore, they are expected as a potential energy resource in the future. Especially, $1m^3$ natural gas hydrate contains up to $172Nm^3$ of methane gas, de pending on the pressure and temperature of production. Such large volumes make natural gas hydrates can be used to store and transport natural gas. In this study, three-phase equilibrium conditions for forming natural gas hydrate were numerically obtained in pure water and single electrolyte solution containing 3 wt% NaCl. The results show that the predictions match the previous experimental values very well, and it was found that NaCl acts as an inhibitor. Also, help gases such that ethane, propane, i-butane, and n-butane reduce the hydrate formation pressure at the same temperature.

• 한국재료학회지
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• 제17권9호
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• pp.453-457
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• 2007

Interest in use of ink-jet printing for pattern-on-demand fabrication of metal interconnects without complicated and wasteful etching process has been on rapid increase. However, ink-jet printing is a wet process and needs an additional thermal treatment such as an annealing process. Since a metal ink is a suspension containing metal nanoparticles and organic capping molecules to prevent aggregation of them, the microstructure of an ink-jet printed metal interconnect 'as dried' can be characterized as a stack of loosely packed nanoparticles. Therefore, during being treated thermally, an inkjet-printed interconnect is likely to evolve a characteristic microstructure, different from that of the conventionally vacuum-deposited metal films. Microstructure characteristics can significantly affect the corresponding electrical and mechanical properties. The characteristics of change in microstructure and electrical resistivity of inkjet-printed silver (Ag) films when annealed isothermally at a temperature between 170 and $240^{\circ}C$ were analyzed. The change in electrical resistivity was described using the first-order exponential decay kinetics. The corresponding activation energy of 0.44 eV was explained in terms of a thermally-activated mechanism, i.e., migration of point defects such as vacancy-oxygen pairs, rather than microstructure evolution such as grain growth or change in porosity.

• 한국응용과학기술학회지
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• 제31권1호
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• pp.143-150
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• 2014

최근 낮은 표면장력, 높은 확산계수, 가스와 같은 낮은 점도, 그리고 액체와 유사한 밀도를 갖는 초임계 유체의 장점을 이용하여 여러 가지 물질의 합성이나 응용 공정에 초임계 유체를 이용하고 있다. 초임계 유체를 이용하여 복합체 제조 시 기존의 용융공정에 비해서 분자들의 움직임이 활발하게 이루어 질 수 있어서 물성의 향상을 기대할 수 있다. 또한 클레이가 고농도로 함유된 마스터 배치를 쉽게 제조할 수 있으며, 기존의 유기 용매를 사용하여 복합체를 제조할 때보다 잔존 용매를 쉽게 제거할 수 있다는 장점을 가지고 있다. 따라서 본 연구에서는 이러한 초임계 이산화탄소를 이용하여 폴리에틸렌옥사이드/클레이 나노복합체를 제조하였다. 또한 본 연구의 목적은 초임계 상태에서 분자들의 활발한 움직임을 기대할 수 있으므로 고분자가 용해되고 클레이 층상으로 효과적으로 삽입되어 복합체의 열적 특성 및 다른 여러 가지 물성을 증가시키는 데 있다. 복합체 제조 후 XRD, TGA, 그리고 DSC를 이용하여 복합체의 특성을 분석 했다. 그 결과 용융방법으로 제조한 복합체보다 열 안정성이 향상되었으며, 클레이 층상 거리도 더 많이 벌어짐을 확인할 수 있었다.

• 산업기술연구
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• 제23권A호
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• pp.199-206
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• 2003

The charcoal-encapsulated methyl silica microcapsules were prepared by a O/W microemulsion sol-gel method, and the adsorption properties on aquatic humic acid were investigated. The capsules prepared were spherical, $100{\sim}1000{\mu}m$ in size. The size distribution was controllable by adjusting the size of charcoal powder, charcoal/methyl silica ratio, and agitating speed in O/W sol-gel process. Adsorption efficiency of charcoal for aquatic humic acid was decreased after encapsulation by methyl silica shell. The decreased adsorption efficiency can be dependent on the decrease of the BET surface area and pore volume after encapsulation. Diffusion properties of humic acid through the capsule shell also played an important role on adsorption efficiency. Therefore, the reasonable target pollutants for the capsules can be VOC or odor molecules which can overcome diffusion barrier through shell of capsules in air condition. Functionalization methods for the charcoal-encapsulated $CH_3(SiO)_n$ microcapsules by incorporation of $TiO_3$ as a phtocatalytic function and by incorporation of inorganic pigment as a color function were also investigated. $TiO_2$ coating properties were controllable by adjusting pH, temperature, and the concentration of $TiOSO_4$. In XRD measurement, the crystal form of the coated $TiO_2$ was anatase. For the colorization of the capsules, inorganic pigments were more efficient than organic dyes, and various color was introduced to the capsules using inorganic pigments.