Copper composite materials have attracted wide attention for energy applications. Especially has a desirable direct band gap of 1.5 eV, which is well matched with the solar spectrum. nanoparticles could make it possible to develop color-tunable nanoparticle emitter in the near-infrared region (NIR) for energy application and bio imaging sensors. In this paper, nanoparticles were successfully synthesized by thermo-decomposition methods. Surface modification of nanoparticles were carried out with various semiconductor materials (CdS, ZnS) for enhanced optical properties. Surface modification and silica coating of hydrophobic nanoparticles could be dispersed in polar solvent for potential applications. Their optical properties were characterized by UV-vis spectroscopy and photoluminescence spectroscopy (PL). The structures of silica coated were observed by transmission electron microscopy (TEM).

Activated magnetite (Fe3O4-δ) was applied to reducing CO2 gas emissions to avoid greenhouse effects. Wet and dry methods were developed as a CO2 removal process. One of the typical dry methods is CO2 decomposition using activated magnetite (Fe3O4-δ). Generally, Fe3O4-δ is manufactured by reduction of Fe3O4 by H2 gas. This process has an explosion risk. Therefore, a non-explosive process to make Fe3O4-δ was studied using FeC2O4·2H2O and N2. FeSO4·7H2O and (NH4)2C2O4·H2O were used as starting materials. So, α-FeC2O4·2H2O was synthesized by precipitation method. During the calcination process, FeC2O4·2H2O was decomposed to Fe3O4, CO, and CO2. The specific surface area of the activated magnetite varied with the calcination temperature from 15.43 m2/g to 9.32 m2/g. The densities of FeC2O4·2H2O and Fe3O4 were 2.28 g/cm3 and 5.2 g/cm3, respectively. Also, the Fe3O4 was reduced to Fe3O4-δ by CO. From the TGA results in air of the specimen that was calcined at 450˚C for three hours in N2 atmosphere, the δ-value of Fe3O4-δ was estimated. The δ-value of Fe3O4-δ was 0.3170 when the sample was heat treated at 400˚C for 3 hours and 0.6583 when the sample was heat treated at 450˚C for 3 hours. Fe3O4-δ was oxidized to Fe3O4 when Fe3O4-δ was reacted with CO2 because CO2 is decomposed to C and O2.

Pure zirconia and x mol% calcia partially stabilized zirconia (x = 1.5, 3, and 8) nanopowders were synthesized by hydrothermal method with various reaction temperatures for 24 hrs. The precipitated precursor of pure zirconia and x mol% calcia doped zirconia was prepared by adding NH4OH to starting solutions; resulting sample was then put into an autoclave reactor. The optimal experimental conditions, such as reaction temperatures and times and amounts of stabilizer CaO, were carefully studied. The synthesized ZrO2 and x mol% CaO-ZrO2 (x = 1.5, 3, and 8) powders were characterized by XRD, SEM, TG-DTA, and Raman spectroscopy. When the hydrothermal temperature was as low as 160˚C, pure ZrO2 and x mol% CaO-ZrO2 (x = 1.5 and 3) powders were identified as a mixture of monoclinic and tetragonal phases. However, a stable tetragonal phase of zirconia was observed in the 8 mol% calcia doped zirconia nanopowder at hydrothermal temperature above 160˚C. To observe the phase transition, the 3 mol% CaO-ZrO2 and 8 mol% CaO-ZrO2 nanopowders were heat treated from 600 to 1000˚C for 2h. The 3 mol% CaO-ZrO2 heat treated at above 1000˚C was found to undergo a complete phase transition from mixture phase to monoclinic phase. However, the 8 mol% calcia doped zirconia appeared in the stable tetragonal phase after heat treatment. The result of this study therefore should be considered as the preparation of 8 mol% CaO-ZrO2 nanopowders via the hydrothermal method.

Red phosphors Ca1-1.5xWO4:Eux3+ were synthesized with different concentrations of Eu3+ ions by using a solid-statereaction method. The crystal structure of the red phosphors was found to be a tetragonal system. X-ray diffraction (XRD) resultsshowed the (112) main diffraction peak centered at 2θ=28.71o, and the size of crystalline particles exhibited an overalldecreasing tendency according to the concentration of Eu3+ ions. The excitation spectra of all the phosphors were composedof a broad band centered at 275nm in the range of 230-310nm due to O2−→W6+ and a narrow band having a peak at 307nmcaused by O2−→Eu3+. Also, the excitation spectrum presents several strong lines in the range of 305-420nm, which areassigned to the 4f-4f transitions of the Eu3+ ion. In the case of the emission spectrum, all the phosphor powders, irrespectiveof Eu3+ ion concentration, indicated an orange emission peak at 594nm and a strong red emission spectrum centered at 615nm,with two weak lines at 648 and 700nm. The highest red emission intensity occurred at x=0.10mol of Eu3+ ion concentrationwith an asymmetry ratio of 12.5. Especially, the presence of Eu3+ in the Ca1-1.5xWO4:Eux3+ shows very effective use of excitationenergy in the range of 305-420nm, and finally yields a strong emission of red light.

귤응애(Panonychus citri)는 감귤의 중요한 응애류 해충으로 다른 잎응애류 (Tetranychidae)와 같이 재배환경에 따라 발생양상이 달라지는 것으로 알려져 있다. 하지만 아직까지 귤웅애의 발생변동 원인에 대한 정량적 또는 정성적인 측면에서 평가는 드문 실정이다. 따라서 본 연구에서는 감귤원에서 초생재배 유무(초생재배 W, 청정재배 NW)와 합성피레스로이드계 살포유무(살포 P, 무살포 NP)를 조합하여 처리하고 귤응애 발생밀도를 조사하여 비교하였다. 초생재배는 천적의 서식처를 제공하여 천적의 정착을 높이므로 귤응애의 발생을 감소시키는 요인으로 가정하였으며, 합성피레스로이드계는 천적의 정착을 방해하여 귤응애의 밀도를 증가시키는 요인으로 가정하였다. 조합처리에 대한 단기효과를 평가하기 위하여 귤응애 봄철 개체군(봄응애)와 가을철 개체군(가을응애) 의 상대적인 크기를 비교하였다. 전체적으로 비교하였을 봄응애 대비 가을응애의 상대적인 증식배수는 NW+NP > NW+P > W+NP > W+P 순으로 감소하였다. 초생재배시 상대적 밀도가 뚜렷이 감소하였으며, 합성피레스로이드계 효과는 뚜렷한 경향을 보이지 않았다. 귤응애 당 이리응애 수의 상대적인 크기 변화는 W+NP 처리구에서 크게 증가하였으며 NW+NP에서도 다소 증가하는 등 합성피레스로이드계를 살포하지 않았을 때 증가하였다. 기타 마름응애와 깨알반날개의 증가율도 합성피레스로이드계를 살포하지 않았을 때 증가하였다. 단기효과에 대하여 종합적으로 판단할 때 귤응애의 발생에는 초생재배의 영향이 더 중요하였고, 천적의 발생에는 합성피레스로이드계의 살포가 더 중요한 것으로 추정되었다. 양자의 상호작용에 대해서는 단기효과로 판단하기 곤란하였다.

The preparation of Sm2O3 doped CeO2 in Igepal CO-520/cyclohexane reverse micelle solutions has been studied. In the present work, we synthesized nanosized Sm2O3 doped CeO2 powders by reverse micelle process using aqueous ammonia as the precipitant; hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of a micro emulsion consisting of cyclohexane as the oil phase, and poly (xoyethylene) nonylphenylether (Igepal CO-520) as the non-ionic surfactant. The synthesized and calcined powders were characterized by Thermogravimetry-differential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD), and Transmission electron microscopy (TEM). The crystallite size was found to increase with increase in water to surfactant (R) molar ratio. Average particle size and distribution of the synthesized Sm2O3 doped CeO2 were below 10 nm and narrow, respectively. TG-DTA analysis shows that phase of Sm2O3 doped CeO2 nanoparticles changed from monoclinic to tetragonal at approximately 560˚C. The phase of the synthesized Sm2O3 doped CeO2 with heating to 600˚C for 30 min was tetragonal CeO2. This study revealed that the particle formation process in reverse micelles is based on a two step model. The rapid first step is the complete reduction of the metal to the zero valence state. The second step is growth, via reagent exchanges between micelles through the inter-micellar exchange.

In this study, the performance of a steel-FRP composite bridge safety barrier was evaluated through the vehicle crash test. Glass fiber and polyester resin were used for FRP. The structural strength performance, the passenger protection performance, and the vehicle behavior after crash were evaluated corresponding to the vehicle crash manual. As the result, A steel-FRP composite safety barrier was satisfied with the required performance.

최근 해양레저에 대한 관심이 높아지면서 요트의 이용과 구매에 대한 관심이 증가됨에 따라 수상 또는 해상의 부유식 구조물이 필요하게 되었으며, 이에 따라 부유식 구조물을 계류하는 방식으로 수중 지반에 커다란 중량 콘크리트 블록을 설치하고 계류삭을 어느 정도 느슨하게 연결하여 계류하는 방식을 사용하고 있다. 하지만 수위차가 나거나 흐름이 있는 곳에서는 부유식구조물 자체가 위치제어가 안되므로, 한곳에 일정하게 머물게 하기 위해서 긴장계류장치(tens

고속도로에서 재령이 20년이 넘는 노후 콘크리트가 늘어남에 따라 콘크리트 포장의 보수/보강이 중요한 이슈로 대두되고 있다. 노후 콘크리트 포장의 보강 대안으로서 아스팔트 덧씌우기가 많이 사용되고 있으나 반사균열 및 포트홀 등 체류수로 인한 문제가 심각하게 대두되고 있다. 본 연구는 반사균열 및 체류수의 문제를 최소화하기 위해 고안된 접착식 방수층을 소개하였으며 포장가속시험을 통해 일반 택코팅을 적용한 합성단면포장과 비교평가를 실시하였다. 실험은 강우를 모사하기 위해 물을 뿌리면서 진행하였고 덧씌우기 포장체의 거동 및 수분 저항 특성을 분석하였다. 연구결과 접착식 방수층은 아스팔트 포장과 콘크리트 포장이 일체로 거동하는 것을 도와주기 때문에 아스팔트 포장체에 발생하는 거동이 일반 택코팅 구간과 완전히 다른 것으로 나타났다. 또 수분의 유입을 최소화하므로 결과적으로 반사균열의 발생을 약 70% 지연시키는 것으로 나타났으며, 체류수로 인한 손상도 줄여주는 것으로 나타났다.

Red phosphors of Gd1-xAl3(BO3)4:Eux3+ were synthesized by using the solid-state reaction method. The phasestructure and morphology of the phosphors were measured using X-ray diffraction (XRD) and field emission-scanning electronmicroscopy (FE-SEM), respectively. The optical properties of GdAl3(BO3)4:Eu3+ phosphors with concentrations of Eu3+ ions of0, 0.05, 0.10, 0.15, and 0.20mol were investigated at room temperature. The crystals were hexagonal with a rhombohedrallattice. The excitation spectra of all the phosphors, irrespective of the Eu3+ concentrations, were composed of a broad bandcentered at 265nm and a narrow band having peak at 274nm. As for the emission spectra, the peak wavelength was 613nmunder a 274nm ultraviolet excitation. The intensity ratio of the red emission transition (5D0→7F2) to orange (5D0→7F1) showsthat the Eu3+ ions occupy sites of no inversion symmetry in the host. In conclusion, the optimum doping concentration of Eu3+ions for preparing GdAl3(BO3)4:Eu3+ phosphors was found to be 0.15mol.

Compared with bulk material, quantum dots have received increasing attention due to their fascinating physical properties, including optical and electronic properties, which are due to the quantum confinement effect. Especially, Luminescent CdSe quantum dots have been highly investigated due to their tunable size-dependent photoluminescence across the visible spectrum. They are of great interest for technical applications such as light-emitting devices, lasers, and fluorescent labels. In particular, quantum dot-based light-emitting diodes emit high luminance. Quantum dots have very high luminescence properties because of their absorption coefficient and quantum efficiency, which are higher than those of typical dyes. CdSe quantum dots were synthesized as a function of the synthesis time and synthesis temperature. The photoluminescence properties were found strongly to depend on the reaction time and the temperature due to the core size changing. It was also observed that the photoluminescence intensity is decreased with the synthesis time due to the temperature dependence of the band gap. The wavelength of the synthesized quantum dots was about 550-700 nm and the intensity of the photoluminescence increased about 22~70%. After the CdSe quantum dots were synthesized, the particles were found to have grown until reaching a saturated concentration as time increased. Red shift occurred because of the particle growth. The microstructure and phase developments were measured by transmission electron microscopy (TEM) and X-ray diffractometry (XRD), respectively.

We present a method of graphene synthesis with high thickness uniformity using the thermal chemical vapor deposition (TCVD) technique; we demonstrate its application to a grid supporting membrane using transmission electron microscope (TEM) observation, particularly for nanomaterials that have smaller dimensions than the pitch of commercial grid mesh. Graphene was synthesized on electron-beam-evaporated Ni catalytic thin films. Methane and hydrogen gases were used as carbon feedstock and dilution gas, respectively. The effects of synthesis temperature and flow rate of feedstock on graphene structures have been investigated. The most effective condition for large area growth synthesis and high thickness uniformity was found to be 1000˚C and 5 sccm of methane. Among the various applications of the synthesized graphenes, their use as a supporting membrane of a TEM grid has been demonstrated; such a grid is useful for high resolution TEM imaging of nanoscale materials because it preserves the same focal plane over the whole grid mesh. After the graphene synthesis, we were able successfully to transfer the graphenes from the Ni substrates to the TEM grid without a polymeric mediator, so that we were able to preserve the clean surface of the as-synthesized graphene. Then, a drop of carbon nanotube (CNT) suspension was deposited onto the graphene-covered TEM grid. Finally, we performed high resolution TEM observation and obtained clear image of the carbon nanotubes, which were deposited on the graphene supporting membrane.

We synthesized porous Co3O4/RuO2 composite using the soft template method. Cetyl trimethyl ammonium bromide (CTAB) was used to make micell as a cation surfactant. The precipitation of cobalt ion and ruthenium ion for making porosity in particles was induced by OH- ion. The porous Co3O4/RuO2 composite was completely synthesiszed after anealing until 250˚C at 3˚C/min. From the XRD ananysis, we were able to determine that the porous Co3O4/RuO2 composite was comprised of nanoparticles with low crystallinity. The shape or structure of the porous Co3O4/RuO2 composite was studied by FE-SEM and FE-TEM. The size of the porous Co3O4/RuO2 composite was 20~40 nm. From the FE-TEM, we were able to determine that porous cavities were formed in the composite particles. The electrochemical performance of the porous Co3O4/RuO2 composite was measured by CV and charge-discharge methods. The specific capacitances, determined through cyclic voltammetry (CV) measurement, were ~51, ~47, ~42, and ~33 F/g at 5, 10, 20, and 50 mV/sec scan rates, respectively. The specific capacitance through charge-discharge measurement was ~63 F/g in the range of 0.0~1.0 V cutoff voltage and 50 mAh/g current density.

본 연구에서는 올레산을 표면개질제로 사용하여 수열법을 통해 수산화 마그네슘을 합성하였다. 수산화 마그네슘은 알카리 조건에서 올레인산과의 반응을 통해 표면 개질된 마이크로 크기의 플레이크 형상을 갖는다. 수열합성에서 수산화 마그네슘 입자 생성의 조건은 pH, 온도 그리고 반응시간이 표면개질과 입자 형상의 주요 변수임을 확인하였다. 생성된 수산화 마그네슘 입자는 FE-SEM, XRD, FT-IR 그리고 TGA를 통해 확인하였다. 유기 용매 내에서의 분산성의 확인은 개질되지 않은 수산화 마그네슘과의 침전 테스트 비교를 통해 확인하였다.

본 연구에서 황색 발색제는 피리딘 존재 하에 α-pivaloyl-2-chloro-5-amino- acetaniline hydrogen chloride와 1-hexadecane sulfonyl chloride를 반응시켜 얻었다. 이 물질은 다양한 분석장비를 이용하여 녹는점, 원소분석기, 적외선분석기, 자외선분석기, 질량분석기로 확인하였다. 황색 발색제를 CD-3(발색현상주약)와 반응시키면 황색이 나타났다.

Catharanthus roseus로부터 생산되는 빈카알칼로이드는 암을 치료하는 데에 사용되는 가장 중요한 천연물 중의 하나이다. 이러한 항암제는 두 단량체 인돌 알칼로이드인 catharanthine과 vindoline의 결합으로 합성될 수 있다. 이 중 vindoline의 생합성에 관계하는 경로를 조사하기 위해서 tabersonine의 메틸기에 중수소를 치환한 전구체인 tabersonine-CD3 1a를 합성하였다. 이는 중수소의 질량 증가로 인해 자연에서 발생하는 tabersonine과 뚜렷이 구별될 수 있도록 해 준다. 우리는 이 중소소가 치환된 tabersonine 1a가 성공적으로 vindoline 생합성경로에 편입되어 중수소가 치환된 3개의 새로운 vindoline 중간체(2a, 3a와 4a)를 생성함을 보였다. 세포현탁배양액에 tabersonine-CD3 1a를 주입한 5일과 13일째에 생성된 대사물인 16-Hydroxytabersonine-CD3 (m/z 356) 2a, 16-Methoxytabersonine-CD3 (m/z 370) 3a와 16-Methoxy-2,3-dihydro-3- hydroxytabersonine-CD3 (m/z 388) 4a의 생성량을 UPLC/MS를 사용하여 측정하였다. 출발물 1a에서 생성물 2a, 그리고 2a에서 3a로의 전환은 빨랐던 반면 3a에서 4a로의 전환은 상대적으로 훨씬 느렸다. 따라서 각 대사물들의 상대적 전환속도를 서로 비교해 보았을 때 vindoline 생합성 과정의 첫 세 단계 중에서 가장 느린 마지막 단계가 속도결정단계임을 암시한다. 즉 대사물 3a에서 4a로의 느린 전환속도의 결과, 배양 후 13일까지도 3a의 축적률이 현저히 증가됨을 보였다. 배양 5일째의 대사물 2a, 3a와 4a의 축적비는 각각 1, 2와 0.1이었다. 그러나 desacetoxyvindoline-CD3 5a, deacetylvindoline-CD3 6a와 vindoline-CD3 7a의 피크는 배양 13일 후에도 발견되지 않아 세포현탁 배양액에 각 생합성단계와 관련된 효소들이 존재하지 않음을 알 수 있었다.

자성유체 유체씰에 사용할 수 있는 마그네타이트를 공침법에 의하여 합성하였다. 마그네타이트의 평균입자크기는 동적광산란 측정장치(DLS)에 의해 약 10-12 nm 로 측정되었다. XRD 측정결과, NH4OH 의 농도가 증가함에 따라 마그네타이트의 결정화도가 증가하였다. 수중 분산된 자성유체의 제타전위는 -49.3 mV 에서 -26.2 mV 까지 DLS에 의하여 측정되었다. 입자의 형상은 구형이었고, 수상과 유상 자성유체에서 스파이킹 효과를 확인하였다.

유화제만을 사용하는 것 보다 더 좋은 유화특성을 갖는 유화보조제에 관한 연구이다. 그 화합물들은 숙신산과 프로필렌글리콜과의 에스테르화 반응에 의하여 합성되었다. 그 구조는 FT-IR과 1H-NMR 분석으로 확인하였다. 표면장력, 임계미셀농도(cmc), 유화력 등 계면특성을 각각 주어진 조건하에서 시험하였다. 그 수용액의 표면장력은 33-35 dyne/cm 이었고, cmc는 표면장력법에 의하여 산정하였다. 그리고, 유화력은 호호바오일의 경우 우수하였다. 결과적으로 합성한 디프로필렌글리콜 숙시네이트는 O/W 유화에서의 유화보조제로서 응용이 기대된다.