• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.563-564
• /
• 2014

Recent developments in the prediction of the contribution of windnoise to the interior SPL have opened a realm of new possibilities in terms of i) how the convective and acoustic sources terms can be identified, ii) how the interaction between the source terms and the side glass can be described and finally iii) how the transfer path from the sources to the interior of the vehicle can be modelled. This work discusses several simulation methods that can be used to represent the physical phenomena involved such as CFD, FEM, BEM, FE/SEA Coupled and SEA. This work focuses on the validation of the wind noise source characterization method and the vibro-acoustic models on which the wind noise sources are applied in the framework of a benchmark proposed by Hyundai Motors Corporation.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.336-336
• /
• 2011

Over the past decades, organic semiconductors have been investigated intensely for their potential in a wide range of optoelectronic device applications since the organic materials have advantages for very light, flexible and low cost device fabrications. In this study, we fabricated small-molecule organic solar cells (OSCs) based on chloro[subphthalocyaninato]boron(III) (SubPc) as an electron donor and $C_{60}$ as an electron acceptor material. Recently SubPc, a cone-shaped molecule with $14{\pi}$-electrons in its aromatic system, has attracted growing attention in small-molecule OSC applications as an electron-donating material for its greater open-circuit voltage (VOC), extinction coefficient and dielectric constant compared to conventional planar metal phthalocyanines. In spite of the power conversion efficiency (PCE) enhancement of small-molecule OSC using SubPc and $C_{60}$, however, the study on the interface between donor-acceptor heterojunction of this system is limited. In this work, SubPc thin films at various thicknesses were deposited by organic molecular beam deposition (OMBD) and the evolution of surface morphology was observed using atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM). We also investigated the influence of film thickness and surface morphology on the PCE of small-molecule OSC devices.

• 대한화학회지
• /
• 제33권3호
• /
• pp.315-320
• /
• 1989

철광석 중에 존재하는 미량 금속원소들을 분석하는 방법을 제시하였다. 분석방법은 ammonium pyrrolidinedithiocarbamate(APDC)-methyl isobutyl ketone(MIBK) 추출계와 원자흡수 분광법(AA)를 이용하였다. 철이 유기층으로 추출되는 것을 막기 위하여 가리움제로서 코발트, 니켈 및 구리의 분석시에는 pH $8{\sim}10$에서 citrate를, 그리고 망간 및 구리의 분석시에는 pH 6{\sim}7$에서 tiron을 가하였다. MIBK의 물에 대한 용해도를 줄이기 위해 NaCl을 염석제로 가하였다. 금속 추출용액의 안정도를 증가시키기 위한 방안으로 MIBK 금속 추출물을 질산 수용액으로 역추출하는 것을 검토하였다.

• Bulletin of the Korean Chemical Society
• /
• 제23권12호
• /
• pp.1769-1772
• /
• 2002

Previous $^{19}F\;and\;^{1,2}H$ electron-nuclear double resonance (ENDOR) study of fluorometmyoglobin (MbF) in frozen-solution state provided sensitive tools sensing subtle structural changes of the heme that are not obtainable from X-ray. [Fann et al., J. Am. Chem. Soc. 1995, 117, 6019] Because of the intrinsic inhomogeneouse EPR line broadening effect of MbF in frozen-solution state, detection of the intrinsic inhomogeneouse EPR line broadening effect of MbF in frozen-solution state, detection of the electronic and geometrical changes of the heme ring itself and the proximal histidine by using $^{14}N$ CW ENDOR was interfered. In the present study, hyperfine-sensitive $^{14}N$ Mims ENDOR technique of pulsed-EPR was employed to probe the changes. With two different $\tau$ values of 128 and 196 ns, $^{14}N$ ENDOR signals of the heme and proximal histidine were completely resolved at $g'_{II}(=g_e=2)$. This study present that X-band $^{14}N$ Mims ENDOR sequence can sensitively detect the small changes of the spin densities and p orbital populations of the proximal and the heme nitrogens, caused by ligand and pH variation of the distal site.

• 한국세라믹학회지
• /
• 제43권9호
• /
• pp.582-587
• /
• 2006

Decomposition behavior of $ferro-Si_3N_4$was investigated with varying temperature and holding time in mud components for high temperature refractory applications. Porosities gradually increased with increasing temperature and holding time due to the carbothermal reduction of $Si_3N_4\;and\;SiO_2$. Silicon monoxide (SiO) as a intermediate resulted from evaporation of $Si_3N_4\;and\;SiO_2$ reacted with C sources to generate needle-like ${\beta}-SiC$ and Fe in $Si_3N_4$ acted as a catalyst in order to enhance growth of SiC grain with the preferred orientation. SiC generation yield increased with increasing holding time, all of the $Si_3N_4\;and\;SiO_2$ affected on SiC formation up to 2h. However, SiC generation was only dependent on residual $SiO_2$ over 2h, because the carbothermal reduction reaction of $Si_3N_4$ was no longer possible at that time.

• 천문학회보
• /
• 제37권2호
• /
• pp.75.1-75.1
• /
• 2012

Narrow-Line Seyfert 1 galaxies are arguably the most important AGN subclass in investigating the origin of the black hole mass-galaxy stellar velocity dispersion (MBH-${\sigma}$) relation because of their high accretion rates close to the Eddington limit. Currently, it is still under discussion whether NLS1s are off from the local MBH-${\sigma}$ relation. We select a sample of 325 NLS1 at relatively low redshift (z<0.1) from the SDSS DR7 by constraining FWHM of $H{\beta}$ in the range of 800-2,200 km/s. Among them, we measured stellar velocity dispersion of 40 objects which show strong stellar absorption lines, e.g. Mg b triplet(${\sim}5175{\AA}$), Fe($5270{\AA}$). In contrast, the other 285 objects show too weak stellar absorption lines to measure velocity dispersion. Using the sample of 40 objects with stellar velocity dispersion measurements, we investigate whether NLS1s follow the same MBH-${\sigma}$ relation as normal galaxies and broad line AGNs. We also test the reliability of the width of narrow lines as a surrogate of stellar velocity dispersion by comparing directly measured stellar velocity dispersion with ${\sigma}$ inferred from [O III], [N II], [S II] line widths, respectively. We will discuss the connection between AGN activity in NLS1s and galaxy evolution based on these results.

• 대한화학회지
• /
• 제33권1호
• /
• pp.113-119
• /
• 1989

양이온 교환수지(Diaion WK 11)를 사용하여 hydrazide 또는 triethylenetetramine 곁사슬을 가진 polymethacrylate계 킬레이트 수지를 만들어 수지중의 질소함량을 원소분석법으로 구한 다음 제조된 수지와 시판 킬레이트수지(Diaion CR 10 및 CR 20)를 금속이온 Cu(II), Co(II), Fe(III)들과 반응시켜 금속 킬레이트수지를 만들었다. 금속의 함량은 킬레이트적정법으로 구하고 수지의 절단면을 electron microprobe X-ray analyzer로 관찰하여 수지내부의 금속의 존재를 확인하였다. 한편, 금속 킬레이트 수지를 hydroxy compounds와 l-ascorbic acid의 산화반응에 이용한 결과 유용한 촉매임을 확인하였다.

• Bulletin of the Korean Chemical Society
• /
• 제25권1호
• /
• pp.79-84
• /
• 2004

The existing technological schemes for processing rhenium-containing raw materials involve the recovery of Re from solutions, which can be effectively achieved by anion exchange method. The application of anion exchange also allows to study rhenium state in aqueous solutions and to develop analytical control methods. The present work is focused on investigation of ion exchange equilibrium in the analytical system Re(VII)-HCl-$SnCl_2$-KSCN-anion exchanger by means of sorption-desorption method as well as by electron, IR- and diffuse reflection spectroscopy. It was shown that rhenium can be quantitatively recovered from this system. It is proposed to use the sorption-spectroscopic method for Re(VII) determination in aqueous solutions. The calibration curve is linear in the concentration range of 0.5-20.0 mg/L (sample volume is 25.0 mL) and the detection limit is 0.05 mg/L. The presence of Mo(VI), Cu(II), Fe(II, III), Ni(II), Zn(II) as well as $K^+,\;Na^+$ do not hinder the solid-phase determination of rhenium. Rhenium (VII) determination by diffuse reflection spectroscopy was carried out in model solutions as well as in samples of river-derived water and in solutions obtained after the dissolution of spent catalysts.

• 한국의류학회지
• /
• 제26권3_4호
• /
• pp.422-430
• /
• 2002

Dyeing properties of the colorants from gromwell on cotton fabric were investigated. The effects of dyeing conditions on dye uptake and the effects of mordants and mordanting methods on K/S value, color change and colorfastness were explored. Gromwell colorants showed low affinity to cotton fabric, and its adsorption isotherm was Freundlich type close to Langmuir type. Therefore, it was considered that hydrogen bonding and Vander Waals force were involved in the adsorption of gromwell colorants to cotton fabric. Pre-mordanting method except Sn mordant gave higher K/S value but it was not significant. Gromwell colorants produced mainly R and RP color on cotton fabric depending on mordants and mordanting method. Dyed cotton fabric showed generally high colorfastness irrespective of mordanting treatment. Light colorfastness was increased by repeat dyeing and Fe and Sn mordanting.

• 한국재료학회지
• /
• 제22권10호
• /
• pp.526-530
• /
• 2012

Silica-based ceramic-matrix composites have shown promise as advanced materials for many applications such as chemical catalysts, ceramics, pharmaceuticals, and electronics. $SiO_2$-CuO-$CeO_2$ multi-component powders and their thin film, using an oxalic acid template as a chelating agent, have larger surface areas and more uniform pore size distribution than those of inorganic acid catalysts. $SiO_2$-CuO-$CeO_2$ composite powders were synthesized using tetraethylorthosilicate, copper (II) nitrate hemi (pentahydrate), and cerium (III) nitrate hexahydrate with oxalic acid as template or pore-forming agent. The process of thermal evolution, the phase composition, and the surface morphology of these powders were monitored by thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffractometry (XRD), field-emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectrometry (EDXS). The mesoporous property of the powders was observed by Brunner-Emmett-Teller surface (BET) analysis. The improved surface area of this powder template with oxalic acid was $371.4m^2/g$. This multi-component thin film on stainless-steel was prepared by sol-gel dip coating with no cracks.