• 천문학회보
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• 제35권1호
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• pp.79-79
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• 2010

To investigate whether the present-day active galaxies follow the same black hole mass vs. stellar velocity dispersion (MBH-$\sigma*$) relation as quiescent galaxies, we measured the velocity dispersions of a sample of local Seyfert 1 galaxies, for which black hole masses were measured via reverberation mapping. We measured stellar velocity dispersions from high S/N optical spectra centered on the Ca II triplet region (${\sim}8500^{\circ}A$), obtained at the Keck, Palomar, and Lick Observatories. For two objects, in which the Ca II triplet region was contaminated by nuclear emission, we used high-quality H-band spectra obtained with the OH-Suppressing Infrared Imaging Spectrograph and laser-guide star adaptive optics at the Keck-II Telescope. Combining our new measurements with data from the literature, we assemble a sample of 24 active galaxies with stellar velocity dispersions and reverberation MBH in the range of black hole mass 106< MBH /$M{\odot}$ < 109,toobtainthefirstreverberationmappingconstraintsontheslopeandintrinsicscatteroftheMBH- $\sigma*$ relation of active galaxies. Assuming a constant virial coefficient f for the reverberation MBH, we find a slope ${\beta}=3.55{\pm}0.60$ and the intrinsic scatter ${\sigma}int=0.43{\pm}0.08$ dex in the relation log (MBH/M${\odot}$)=$\alpha+\beta$ log(${\sigma}*$/200 km s-1), which are consistent with those found for quiescent galaxies. We derive an updated value of the virial coefficient f by finding the value which places the reverberation masses in best agreement with the MBH - $\sigma*$ relation of quiescent galaxies; using the quiescent MBH - $\sigma*$ relation determined by Gultekin et al. we find log f=0.72+0.09 (or $0.71{\pm}0.10$) with an intrinsic scatter of $0.44{\pm}0.07$ (or 0.46+0.07) dex. No correlations between f and parameters connected to the physics of accretion (such as the Eddington ratio or line-shape measurements) are found. The uncertainty of the virial coefficient remains one of the main sources of the uncertainty in black hole mass determination using reverberation mapping, and therefore also in single-epoch spectroscopic estimates of black hole masses in active galaxies.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1367-1372
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• 2008

A plate type supporting structure of a tube bundle in axial flow generates a certain band of a high frequency periodic excitation of a vortex shedding and/or a flow separation due to sharp edge of the plate thickness and a severe pressure drop due to a cross-sectional area of the supports. With a design consideration of the low vibration and a small flow resistance, the analysis method is uniquely confined to an experimental approach because a complex geometry of a cylindrical tube bundle and/or physical phenomena related to the fluid-structure interaction of tube bundle in a flow impede a theoretical or a numerical approach. A 5x5 cylindrical tube bundle with 5 supports which were discretely located along the bundle's axis was tested in the FIVPET hydraulic test loop for a design evaluation and an analysis perspectives. A high frequency flow-induced vibration of the supporting structures of the cylindrical tube bundle was measured at a outer surface of a supporting structure through a transparent flow housing by the laser dopper vibrometer. Pressure drop in-between three measurement distances was measured by the differential pressure transmitter. High frequency vibration and pressure drop fairly depends on the geometric design of supporting structure. So, these two parameters would be used as a qualitative design variables for design evaluation and analysis.

• Asian-Australasian Journal of Animal Sciences
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• 제19권2호
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• pp.171-175
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• 2006

The aim of this in vitro study was to test the effect of microinjection (Mi) of foreign gene into the rabbit egg pronucleus and epidermal growth factor (EGF) addition on the blastocyst rate, the cell number and the diameter of embryos, and to determine possible relationships between embryo cell number and embryo diameter. Blastocyst rate was significantly decreased in gene- Mi (G-Mi/E0) group (63.1%) comparing to intact ones (83.5%, $p_1$<0.05). The addition of EGF at 20ng/ml (G-Mi/E20) or 200 ng/ml (GMi/ E200) to gene-Mi embryos did not affect blastocyst rate (65.6 and 55.2% resp.). As a control for Mi, the eggs were microinjected with the same volume of phosphate-buffered solution (PBS-Mi) instead of the gene construct solution. Cell numbers and embryo diameters were measured from embryo images obtained on confocal laser scanning microscope. Bonferroni-modified LSD test showed that the embryo cell number in PBS-Mi group was significantly lower ($p_1$<0.05) and in gene-Mi group was tended to decrease compared with intact embryos. Embryo diameter was not different among experimental groups. No effect of EGF given at any doses both on the cell number and embryo diameter was found. A positive correlation between cell number and embryo diameter was observed in all groups of embryos. Since embryo diameter was not changed under the influence of Mi or EGF addition in this study, this seems to be more conservative characteristics of the embryo morphology. These results suggest that the pronuclear microinjection compromises developmental potential of embryos, decreasing blastocyst rate and embryo cell number, whilst embryo diameter is not affected. No effects of EGF on studied parameters were confirmed. Declined quality of Mi-derived embryos is caused by the microinjection procedure itself, rather than by the gene construct used.

• 지질공학
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• 제23권3호
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• pp.271-281
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• 2013

본 연구에서는 임기광산과 일광광산의 시료를 활용하여 동결/융해 실험을 진행하고 시료의 물성변화 및 표면 거칠기의 변화를 관찰하여 풍화양상을 분석하였다. 본 연구에서 사용된 동결/융해 실험의 온도 범위는 우리나라의 여름과 겨울철의 온도를 고려하여 $-20^{\circ}C$ ~ $+40^{\circ}C$로 설정하고 각각 설정한 온도까지 도달하는데 각 1시간, 목표온도를 유지하는데 1시간으로 총 4시간을 1 주기(cycle)로 하여 매 20 주기마다 풍화양상을 관찰하였다. 그 결과 동결/융해 시험의 반복횟수가 증가하면서 시료의 측정된 물성 값 중 공극률(porosity)은 두 개의 지역에서 0.05%와 0.15%의 차이를 보이며 증가하였고, 입자의 부피와 건조질량, 포화질량은 비교적 미세하게 감소하는 경향을 보였다. 또한, 다초점 레이저 스캔 현미경을 통해서는 측정한 선 거칠기와 면 거칠기 인자의 값들은 시간이 경과함에 있어 일정하게 증가 및 감소하는 경향을 보였으며, 다초점 레이저 스캔 현미경을 통해 촬영한 사진에서도 표면 거칠기가 변하는 것을 확인할 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.371-372
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• 2012

We have studied lead-based gapless semiconductors, $PbPdO_2$, which is very sensitive to external parameters such as temperature, pressure, electric field, etc[1]. We have fabricated pure $PbPdO_2$, Co- and Mn-doped $PbPdO_2$ thin films using the pulsed laser deposition. Because of the volatile element of Pb, it is very difficult to grow the films. Note that in case of $MgB_2$, Mg is also volatile element. So in order to enhance the quality of $MgB_2$, some experiments are carried out in annealing with Mg-rich atmosphere [2]. This annealing process with volatile element plays an important role in making smooth surface. Thus, we applied such process to our studies of $PbPdO_2$ thin films. As a result, we found the optimal condition of ex-situ annealing temperature ${\sim}650^{\circ}C$ and time ~12 hrs. The ex-situ annealing brought the extreme change of surface morphology of thin films. After ex-situ annealing with PbO-rich atmosphere, the grain size of thin film was almost 100 times enlarged for all the thin films and also the PbO impurity phase was smeared out. And from X-ray diffraction measurements, we determined highly crystallized phases after annealing. So, we measured electrical and magnetic properties. Because of reduced grain boundary, the resistivity of ex-situ annealed samples changed smaller than no ex-situ sample. And the carrier densities of thin films were decreased with ex-situ annealing time. In this case, oxygen vacancies were removed by ex-situ annealing. Furthermore, we will discuss the transport and magnetic properties in pure $PbPdO_2$, Co- and Mn-doped $PbPdO_2$ thin films in detail.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.409-409
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• 2011

All solid-state thin film lithium batteries have many applications in miniaturized devices because of lightweight, long-life, low self-discharge and high energy density. The research of cathode materials for thin film lithium batteries that provide high energy density at fast discharge rates is important to meet the demands for high-power applications. Among cathode materials, lithium manganese oxide materials as spinel-based compounds have been reported to possess specific advantages of high electrochemical potential, high abundant, low cost, and low toxicity. However, the lithium manganese oxide has problem of capacity fade which caused by dissolution of Mn ions during intercalation reaction and phase instability. For this problem, many studies on effect of various transition metals have been reported. In the preliminary study, the Sn-substituted LiMn2O4 thin films prepared by pulsed laser deposition have shown the improvement in discharge capacity and cycleability. In this study, the thin films of LiMn2O4 and LiSn0.0125Mn1.975O4 prepared by RF magnetron sputtering were studied with effect of deposition parameters on the phase, surface morphology and electrochemical property. And, all solid-state thin film batteries comprised of a lithium anode, lithium phosphorus oxy-nitride (LiPON) solid electrolyte and LiMn2O4-based cathode were fabricated, and the electrochemical property was investigated.

• 한국수정란이식학회지
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• 제27권1호
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• pp.37-43
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• 2012

This study evaluated a method of sorting X and Y chromosomes based on size using the forward angle light scatter related refractive index (FSC) of a flow cytometer. Hanwoo bulls sperm were separated to X and Y chromosomes by the parameters of FSC or Hoechst 33342 intensity. As a result, using monitor program linked flow cytometry during sorting processing, the purities were $97{\pm}0.57$ or $96{\pm}0.67%$ for the X-fraction and $96{\pm}0.33$ or $97{\pm}1.33%$ for the Y-fraction in the two sperm sorting methods. There were no differences in the X and Y ratios (X and Y %) between the sperm sorting methods based on FSC or DNA content. The proportions of female and male embryos used for in vitro fertilization and development were $66.03{\pm}3.31$ or $69.37{\pm}1.41%$, and $70.56{\pm}2.42$ or $56.11{\pm}3.09%$ when sperm were processed using the sex sorting method by FSC or Hoechst 33342. In conclusion, further study is needed to determine the optimum procedure and improve the nozzle to enhancing sorting accuracy or efficiency. Also, the findings of this study do not negate the possibility that the difference method of sperm sorting cannot use a UV laser beam.

• 대한공간정보학회지
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• 제19권1호
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• pp.79-86
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• 2011

최근 수치표고모델(DEM : Digital Elevation Model)을 구축하기 위한 목적으로 항공레이저측량(LiDAR : Light Detection And Ranging) 기술이 주목받고 있다. DEM은 항공레이저측량으로부터 획득된 라이다 데이터에서 지면점만 추출한 수치지면자료(DTD : Digital Terrain Data)의 정확성에 의해 그 품질이 좌우된다. 하지만 원시자료에서 수치지면자료를 추출하기 위한 자동 필터링 작업은 필터링 알고리즘의 한계 및 라이다 데이터의 고유한 특성으로 인하여 항상 오분류 영역이 발생한다. 따라서 이를 보완하기 위해서는 작업자에 의한 수동분류 작업이 반드시 필요하다. 본 연구에서는 수동 작업이 원활하게 이루어 질 수 있도록 자동 필터링 작업에서 얻어진 수치지면자료에서 오분류 될 가능성이 있는 영역을 자동으로 탐지하는 알고리즘을 제안한다. 제안된 알고리즘은 2D 격자 구조를 적용하였으며 'Slope Angle', 'Slope DeltaH', 'NNMaxDH(Nearest Neighbor Max Delta Height)'로 명명한 매개변수를 사용하였다. 실험 결과, 제안된 알고리즘은 지형형태나 라이다 데이터 평균 점밀도에 제한받지 않는 안정적인 결과를 보여주었다.

• 한국자동차공학회논문집
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• 제12권6호
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• pp.38-45
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• 2004

This paper studies the effects of intake port configuration on the swirl that is key parameter in the flow field of direct injection diesel engines. In-cylinder flow characteristics is known to have significant effects on fuel air mixing, combustion and emissions. To investigate the swirl flow generated by various intake ports, steady state flow tests were conducted to evaluate the swirl. Helical port geometry, SCV shape and bypass were selected as the design parameters to increase the swirl flow and parametric study was performed to choose the optimal port shape that would generate a high swirl ratio efficiently. The results revealed that a key factor in generating a high swirl ratio was to suitably control the direction of the intake air flow passing through the valve seat. For these purposes, we changed the distance of helical and tangential port as well as installed bypass near the valve seat and the effects of intake port geometry on in-cylinder flow field were visualized by a laser sheet visualization method. From the experimental results, we found that the swirl ratio and mass flow rate had a trade off relation. In addition, the result indicates that the bypass is a effective method to increase the swirl ratio without sacrificing mass flow rate.

• 접착 및 계면
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• 제5권2호
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• pp.14-26
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• 2004

For reliable determination of mechanical characteristics of adhesively bonded joints used e.g. as input data for computer-aided design of complex components, the thick-adherend tensile-shear test according to ISO 11003-2 is the most important material testing method. Although the total displacement of the joint is measured across the polymer layer directly in the overlap zone in order to minimize the influence of the stepped adherends, the substrate deformation must be taken into account within the framework of the evaluation of the shear modulus and the maximum shear strain, at least when high-strength adhesives are applied. In the standard ISO 11003-2 version of 1993, it was prescribed to perform the substrate deformation correction by means of testing a one-piece reference specimen. The authors, however, pointed to the excessive demands on the measuring accuracy of the extensometers connected with this technique in industrial practice and alternatively proposed a numerical deformation analysis of a dummy specimen. This idea of a mathematical correction was included in the revised ISO 11003-2 version of 2001 but in the simplified form of an analytical method based on Hooke's law of elasticity for small strains. In the present work, it is shown that both calculation techniques yield considerably discordant results. As experimental assessment would require high-precision distance determination (e.g. laser extensometer), finite element analyses of the deformation behavior of the bonded joint are performed in order to estimate the accuracy of the obtained substrate deformation corrections. These simulations reveal that the numerical correction technique based on the finite element deformation modeling of the reference specimen leads to considerably more realistic results.