SnO2-CoO/carbon-coated CoO core/shell nanowire composites were synthesized by using electrospinning and hydrothermal methods. In order to obtain SnO2-CoO/carbon-coated CoO core/shell nanowire composites, SnO2-Co3O4 nanowire composites and SnO2-Co3O4/polygonal Co3O4 core/shell nanowire composites are also synthesized. To demonstrate their structural, chemical bonding, and morphological properties, field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were carried out. These results indicated that the morphologies and structures of the samples were changed from SnO2-Co3O4 nanowires having cylindrical structures to SnO2-Co3O4/Co3O4 core/shell nanowires having polygonal structures after a hydrothermal process. At last, SnO2-CoO/carbon-coated CoO core/shell nanowire composites having irregular and high surface area are formed after carbon coating using a polypyrrole (PPy). Also, there occur phases transformation of cobalt phases from Co3O4 to CoO during carbon coating using a PPy under a argon atmosphere.

금속이 도핑 된 산화아연 나노클러스터를 합성하기 위해 마이크로웨이브를 이용한 폴리올 공 정은 빠르고 경제적인 합성 방법이다. 디에틸렌글리콜은 높은 분극률과 마이크로파의 흡수 능력이 뛰어 나며, 높은 온도상승 비율과 반응시간을 짧게 해준다. 본 연구에서는 금속이 도핑 된 산화아연 나노클러 스터를 합성하기 위해서 첨가되는 seed의 부피비를 다르게 하여 얻었으며, 전구체로는 아세트산 아연 2 수화물, 도핑 금속은 아세트산 금속 염을 그리고 용매로서 디에틸렌글리콜을 사용하였다. 금속이 도핑 된 산화아연 클러스터는 FE-SEM, XRD, Raman, PSA로 특성을 확인하였다.

본 연구에서는 ethyl acrylate monomer(EAM)을 사용한 수용성 아크릴 수지를 합성한 후 monoammonium phophate를 수용액 상태로 녹인 뒤 이를 아크릴 수지에 함양을 달리한 시료를 준비하 여 각각의 필름 상태 및 피혁 외부에 코팅하여 기계적 물성측정 및 열안정성 물성 측정 실시하여 각각 의 시료를 비교 검토 하였다. DSC를 이용한 열안정성 측정 결과 monoammonium phosphate 함량이 높은 시료(WAC-APS3) 의 Tm 값이 410℃ 로 가장 높은 열안정성을 확인할 수 있었다. 내용제성 측정 결과 아크릴 수지 및 브랜딩 된 수지 모두 높은 내용제성을 확인 할 수 있었다. 내마모성 측정결과는 monoammonium phosphate 함량이 높은 수지가 우수한 물성(68.729 mg.loss)을 보였으나, 인장 강도, 연신율 측정치에서는 monoammonium phosphate 함량이 높아질수록 물성이 저하되어 아크릴 수지의 인장력인 1.505 kgf/㎟ 보다 낮은 1.275 kgf/㎟ 이 측정되었으며, 연신율의 경우 수용성 아크릴 수지 단 독 시료의 연신율인 425% 보다 낮은 384% 가 측정되었다.

Naphthothiazolo carbocyanine is of industrial importance as red-sensitizing dye in the spectral sensitization. Sensitizing dye was prepared by the reaction of 2-methyl-3- sulfopropyl-4,5-naphthothiazolium (inner salt) with triethyl orthopropionate in the presence of triethylamine. The product was identified by using various analytical tools such as elemental analyzer, IR spectrophotometer, UV-Vis spectrophotometer, 1H-NMR spectrometer, TGA and DSC. The maximum absorption peak in methanol solvent was 578nm. Therefore, it was concluded that naphthothiazolo carbocyanine dye can be used as sensitizing dye for the spectral sensitization of photographic emulsion and color cosmetics.

Dinitramide(N(NO2)2)염 화합물은 현재 고체 산화제로 로켓추진제의 중요한 원료 물질 중 하나이며, 환경 및 인체에 독성이 적은 친환경 에너지물질로 알려져 군사적 목적 외에 다양한 가스발생 제로서 사용되고 있다. 특히 무기염이 아닌 유기염인 Guanidine 염(GDN)은 수분에 대한 안정성이 향 상되어 안정적 보관 및 제조가 가능하므로 고순도 물질의 대량 생산이 가능하다. GDN의 출발물질로 guanidine의 음이온 염인 acetate, chloride, carbonate, nitrate, sulfate를 사용하여, GDN(GDN-1,2,3,4,5)을 최대 99%의 수율로 합성하였고, 이들의 물성을 다양한 분석기기를 이용하여 평가하였다. 흡수파장은 3452, 3402, 3354, 3278, 3208, 1642, 1570, 1492, 1416, 1337, 1179, 1000 cm-1이 공통적으로 관찰되었으며, 열적 특성 변화는 130 ℃에서 일어나기 시작하며 150℃~160 ℃에서 는 발열반응과 함께 물질의 변화가 관찰되었다.

We synthesized Fe-doped TiO2/α-Fe2O3 core-shell nanowires(NWs) by means of a co-electrospinning method anddemonstrated their magnetic properties. To investigate the structural, morphological, chemical, and magnetic properties of thesamples, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectronspectroscopy were used, as was a vibrating sample magnetometer. The morphology of the nanostructures obtained aftercalcination at 500oC exhibited core/shell NWs consisting of TiO2 in the core region and α-Fe2O3 in the shell region. In addition,the XPS results confirmed the formation of Fe-doped TiO2 by the doping effect of Fe3+ ions into the TiO2 lattice, which canaffect the ferromagnetic properties in the core region. For comparison, pure α-Fe2O3 NWs were also fabricated using anelectrospinning method. With regard to the magnetic properties, the Fe-doped TiO2/α-Fe2O3 core-shell NWs exhibited improvedsaturation magnetization(Ms) of approximately ~2.96emu/g, which is approximately 6.1 times larger than that of pure α-Fe2O3NWs. The performance enhancement can be explained by three main mechanisms: the doping effect of Fe ions into the TiO2lattice, the size effect of the Fe2O3 nanoparticles, and the structural effect of the core-shell nanostructures.

Cu2O nanowires were synthesized at large scale on copper plate by thermal oxidation in air. The effect of oxidation time and temperature on the morphology of the nanowires was examined. The oxidation time had no effect on the diameter of the nanowires, while it had a great effect on the density and the length of the nanowires. The density and the length of the nanowires increased, and then decreased, with increasing oxidation time. The oxidation temperature had a tremendous effect on the size-distribution as well as the density of the nanowires. When the oxidation temperature was 700˚C, uniform size-distribution and high density of the nanowires was achieved. At lower and higher temperatures, the density of the nanowires was lower, and they displayed a broader size-distribution. It is suggested that the Cu2O nanowires were grown via a vapor-solid mechanism because no catalyst particles were observed at the tips of the nanowires.

Inorganic pigments have high thermal stability and chemical resistance at high temperature. For these reasons, they are used in clay, paints, plastic, polymers, colored glass and ceramics. CoAl2O4 nano-powder was synthesized by reverse-micelle processing the mixed precursor(consisting of Co(NO3)2 and Al(NO3)3). The CoAl2O4 was prepared by mixing an aqueous solution at a Co:Al molar ratio of 1:2. The average particle size, and the particle-size distribution, of the powders synthesized by heat treatment (at 900; 1,000; 1,100; and 1,200˚C for 2h) were in the range of 10-20 nm and narrow, respectively. The average size of the synthesized nano-particles increased with increasing water-to-surfactant molar ratio. The synthesized CoAl2O4 powders were characterized by X-ray diffraction analysis(XRD), field-emission scanning electron microscopy(FE-SEM) and color spectrophotometry. The intensity of X-ray diffraction of the synthesized CoAl2O4 powder, increased with increasing heating temperature. As the heating temperature increased, crystal-size of the synthesized powder particles increased. As the R-value(water/surfactant) and heating temperature increased, the color of the inorganic pigments changed from dark blue-green to cerulean blue.

A spherical Sr4Al14O25:Eu2+ phosphor for use in white-light-emitting diodes was synthesized using a liquid-state reaction with two precipitation stages. For the formation of phosphor from a precursor, the calcination temperature was 1,100˚C. The particle morphology of the phosphor was changed by controlling the processing conditions. The synthesized phosphor particles were spherical with a narrow size-distribution and had mono-dispersity. Upon excitation at 395 nm, the phosphor exhibited an emission band centered at 497 nm, corresponding to the 4f65d→4f7 electronic transitions of Eu2+. The critical quenching-concentration of Eu2+ in the synthesized Sr4Al14O25:Eu2+ phosphor was 5 mol%. A phosphor-converted LED was fabricated by the combination of the optimized spherical phosphor and a near-UV 390 nm LED chip. When this pc-LED was operated under various forward-bias currents at room temperature, the pc-LED exhibited a bright blue-green emission band, and high color-stability against changes in input power. Accordingly, the prepared spherical phosphor appears to be an excellent candidate for white LED applications.

CaWO4:Smx(x=0, 0.5, 1.0, 1.5, 2.0mol%) white phosphors with different concentrations of Sm3+ ions weresynthesized using the hydrothermal method. The crystal structure, surface, and optical properties of the CaWO4:Smphosphors were investigated using X-ray diffraction(XRD), field-emission scanning electron microscopy(FE-SEM),photoluminescence(PL) and photoluminescence excitation(PLE). From the XRD results, the crystal structure of theCaWO4:Sm phosphors was found to be tetragonal. The CaWO4:Sm phosphors became more cohesive with increasing Sm3+-ion concentration. The photoluminescence excitation(PLE) peak of the phosphors, at around 250nm, was ascribed to thetransition from the 1A1 ground-state to the high-vibration level of 1T2 in the WO42− complex. The maximum emissionspectra of the phosphors were observed when the Sm3+ concentration was 0.5mol%. The luminescence intensity of theCaWO4 phosphors was decreased for Sm3+ concentrations greater than 0.5mol%.

Cobalt nano-rods were fabricated using a template-free electrochemical-deposition process. The structure of cobalt electro-deposits strongly depends on the electrolyte composition and on the density of the applied current. In particular, as the content of boric acid increased in the electrolyte, deposits of semi-spherical nuclei formed, and then grew into one-dimensional nano-rods. From analysis of the electro-deposits created under the conditions of continuous and pulsed current, it is suggested that the distribution of the active species around the electrode/electrolyte interface, and their transport, might be an important factor affecting the shape of the deposits. When transport of the active species was suppressed by lowering the deposition temperature, more of the well-defined nano-rod structures were obtained. The optimal conditions for the preparation of well-defined nano-rods were determined by observing the morphologies resulting from different deposition conditions. The maximum height of the cobalt nano-rods created in this work was 1μm and it had a diameter of 200 nm. Structural analysis proved that the nano-rods have preferred orientations of (111).

본 연구에서는 hard segment를 형성하고 있는 폴리우레탄을 합성한 다음 피혁산업에서 마감 코팅시 많이 사용되고있는 폴리에틸렌왁스의 적하량을 점차 증가시켜 필름 및 Lam skin에 코팅에 적용하여 변화하는 물성을 측정하였다. 내용제성 측정 결과 높은 내용제성 물성을 지닌 폴리우레탄 수지에 폴리에틸렌왁스의 함량에 따른 물성적 변화는 크게 나타나지 않았다. 인장 강도 측정치에서는 폴리우레탄 단독 필름의 측정치가 1.235 kgf/㎟로 가장 높은 수치를 나타내었으며, 폴리에틸렌왁스의 함량이 제일 높은 PUD-EW3가 가장 낮은 인장력 1.022 kgf/㎟를 나타내었다. 또한 내마모도 측정에서는 PUD가 제일 높은 52.22 5㎎.loss로 우수한 물성변화를 나타내었고, 연실율의 경우 역시 우레탄 단독 코팅인 PUD가 698%로 가장 높은 수치를 나타내었다.

동역학의 새로운 변분이론인 혼합 합성 변분이론은 수학물리학을 비롯한 공학에 있어 초기치-경계치 문제해석에 광범위하게 적용될 수 있는 기반을 제공하는 것으로, 본 논문은 이 이론을 토대로 시간에 대한 이차의 형상함수가 적용된 시간 유한요소해석법을 개발하고 그 해석법의 수치특성 확인을 통해 향후 다양한 동적시스템 해석의 적용에 대한 가능성을 살펴보았다. 이를 위해 가장 기본적인 선형탄성의 단자유도계가 고려되었다. 에너지 보존시스템의 경우(비감쇠 시스템에 외력이 작용치 않는 경우), 제안된 알고리즘 모두는 time-step에 관계없이 안정적이며 수치감쇠가 없이 에너지와 모멘텀이 보존되는 symplecticity property를 가지고 있음을 확인할 수 있었고, 감쇠시스템인 경우, time-step이 점점 작아질수록 정확한 해에 빠르게 수렴하는 것을 확인하였다.

Trametes versicolor showed the ability of degrading synthetic dyes such as congo red (CR) and methylene blue (MB) in solid and liquid culture conditions. The T. versicolor strains isolated in Korea degraded MB more efficiently than CR, differently most of other white mushrooms known to have difficulties in degrading MB than other dyes. Thus the Koren strains of T. versicolor showed the commercial potential to be used for cleaning dye-contaminated region without any patent-related problem. The main enzyme responsible for dye deradation was laccase. The manganese peroxidase (MnP) was also detected and supposed to be involved in the degradation process of synthetic dyes. However, no lignin peroxidase (LiP) was detected from degradation process, indicating LiP is not the enzyme T. versicolor use to degrade CR and MB.

Carbazole과 diketopyrrolopyrrole를 기본 골격으로 한 2,5-bis-(2-butyl-octyl)-3,6-bis-[5-(4-carbazol-9-ylphenyl)-thiophen-2-yl] -2,5-dihydro-pyrrolo[3,4-c]pyrrole-1,4-dione (PCTDPP12)을 스즈키 커플링 반응을 이용하여 합성하였다. UV-Visible 분광법으로 확인 한 결과 PCTDPP의 용액과 필름의 최대 흡수 피크는 각각 643 nm와 671 nm이며, PCTDPP12의 광학적 밴드갭은 각각 1.84 eV이다. 열처리에 의해 PCTDPP12의 UV-visible 흡광도 및 최대 흡수 파장이 변화된는 것을 관찰 하였다. 그리고 순환 전압 전류법에 의해 조사한 PCTDPP12의 HOMO 및 LUMO 에너지 준위는 –5.34 eV와 -3.54 eV 이다.