• Journal of Astronomy and Space Sciences
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• v.2 no.2
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• pp.101-115
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• 1985

Using Brandt model the mess distribution of the late type spiral galaxy NGC 6946 was derived, and the total mass was reestimated to understand the M/L ratio of this galaxy. Two kinds of the rotation curve with shape parameter n=1 and 3.3 were examined. The following are the main results; (1) The total masses of NGC 6946 are $3.1\times$$10^{11}$ M(n=1) AND $2.8\times$$10^{11}$ M(n=3.3) respectively. and the corresponding M/L are about 17 and 16 for both cases. (2) The optical image in the blue light, whose radius is 9.6 kpc, has 8$\times$$10^{10}$ M and 1.4$\times$$10^{11}$ M. These give the value of M/L about 5 and 8 respectively. (3) The masses and M/L of the nuclear region within 1.2 kpc are 4.0$\times$$10^{9}$ M 4.7$\times$$10^9$ M and 3, 4 for both cases. Those of the disk from 1.2 kpc to 9.6 kpc are 7.6$\times$1$10^{10}$M, 1.4$\times$$10^{11}$M, and 5, 8. (4) The masses of the outer halo extended to few hundreds kiloparsecs are 2.3$\times$$10^{11}$ M and 1.4$\times$$10^{11}$M. The corresponding M/L are about 62 and 37.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.35.2-35.2
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• 2018

Using the K-band Multi-object Spectrograph (KMOS) at the Very Large Telescope (VLT), the KMOS Redshift One Spectroscopic Survey (KROSS) has gathered integral-field data for ~800 star-forming galaxies at a redshift z~1, when the universe was roughly half its current age and forming the bulk of its stars. With spatially-resolved observations, KROSS reveals galaxies that are both gas-rich and highly turbulent. It is possible to derive the observed and baryonic Tully-Fisher (luminosity - rotation velocity) relations, thus constraining the mass-to-light ratios and total (luminous + dark) masses of the galaxies. This in turn highlights the dependence of the relation zero-point on the degree of rotational support of the galaxies (rotational velocity to velocity dispersion ratio). By degrading and analogously analysing integral-field data of hundreds of local galaxies from the Sydney-AAO Multi-object Integral-field Spectrograph (SAMI) survey, a robust comparison z=0 Tully-Fisher relation can also be derived, thus further constraining the luminous and dark mass growth of disk galaxies over the last 7 billions years. This unique comparison also reveals that systematic effects associated with sample selection and analysis methods are as large as the effects expected from cosmological evolution, and thus that most other comparisons employing heterogeneous data and/or methods can safely be ignored.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.967-972
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• 1997

Recovery of aromatics in extract phase which was obtained by batch equilibrium extraction between light cycle oil(LCO) and dimethylsulfoxide(DMSO) solution as solvent was investigated by re-extraction. To select the most suitable re-extraction solvent for recovery of aromatics in extract phase, distribution equilibrium was measured between extract phase and solvents. The solvents used were benzene(B), toluene(T), m-Xylene(mX), n-hexane(Hx) and n-hexane(Hx) and n-Octane(Ot). From the distribution coefficients and yields of aromatics, Hx seemed to be the most suitable. Furthermore, effects of operation parameters for re-extraction of aromatics in the extract phase were studied by batch equilibrium re-extracion with Hx as solvent. Yields of aromatics were found to increase with increasing solvent/feed (extract phase) mass ratio(S/F), while distribution coefficients of aromatics were fixed irrespective of S/F used. Operating temperature did not affect distribution coefficients and yields of aromatics. Distibution coefficients and yields of naphthalene group(carbon numer : 10~12) increased with increasing cabon number. Mass transfer rates of aromatics were also measured with a batch stirred vessel.

• Journal of Astronomy and Space Sciences
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• v.12 no.1
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• pp.21-29
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• 1995

The $\beta$ Lyrae-type eclipsing binary AW Cam was observed photoelectrically in three wavelength regions. The obtained UBV light curves of AW Cam were analyzed with two separate modes(mode 2 for detached systems and mode 5 for semi-detached ones) of the Wilson-Devinney binary mode. It is intended to resolve the discrepancy in AW Cam system that the photometrio mass ratio (q=0.21) derived by Russo and Milano (1983) is not consistent with the spectroscopic result (q=0.43) by Mammano et al.(1967). Our photomtric solutions derived with mode 2 are fitted better to the observed light curves than those of mode 5, supporting that AW Cam may be not a normal semi-detached system but a detached one. Three dimensional Roche configuration of AW Cam system calculated with the derived mass ratio (q=0.43) reveals that the less massive secondary with the confined within its inner Roche lobe, while the more massive rimary is in marginally contact. From the Roche geometry, the constancy of the orbital period and other photometric evidences of AW Cam, it is provisionally concluded that the system is an unevolved detached binary in is provisionally concluded that the system is an unevolved detached binary in the phase of case A evolution toward 'contact phase' rather than and evolved one in 'broken-contact phase' suggested by Giuricin and Mardrossian (1981).

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.43-46
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• 2007

Though bottom emission AM-OLED has advantages in respect of mass production, the bottom emission type is underrated due to its low aperture ratio and low color gamut, compared with top emission type. In this paper, we demonstrate that the color gamut up to 89 % can be simply achieved by depositing dielectric multilayers, whose thicknesses are determined using an optical simulation program, prior to formation of Si layer.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.125-132
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• 2011

This paper describes current status and future prospects of the mass production of microalgae biomass. Microalgae have attracted considerable attention since they not only effectively fix $CO_2$ gas during their metabolic process but also have the great potential to be utilized for producing valuable substances as a kind of efficient light-harvesting cell factories. In this review, we outline various types of photobioreactors employed for mass production of biomass by culturing microalgae in a well controlled way and give an overview about the present state of affairs, both domestic and international, in the field of the microalgal culturing technologies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.602-608
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• 2002

The flexible structure like solar array and antenna in spacecraft shows very sensitive responses to the inner or outer disturbance and noise. And the spacecraft becomes more complex and larger as it has various mission and role. But since the spacecraft need to have the limited mass, the thin and light material should be selected and this necessity induces the decrease d natural frequency and structural stiffness. It reduces the ability of adapting to the disturbance and induces the structural unstability. Certainly, the disturbance does not only make the structural unstability, but also give the bad effect to the precise attitude control. So it is necessary to control the vibration in the space. In this paper, the flexible structure control modeling with piezo sensor and piezo actuator is developed. The model uncertainty of damping ratio is overcome by robust control. The system equation is induced by the finite element method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.156-157
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• 2016

Oyster shell is produced by shucking process in oyster farming in southern coast of Korea. In average, about 6.7kg of oyster shell is produced as an industrial waste for 1kg of oyster flesh, and even only in last year, it is estimated that about 150,000 ton of oyster shell is produced. Oyster shell is light weighted and the strength characteristic of it is similar to sand. So we produced mortar test using different law of multiple proportions of grounded oyster shell powder of its particle size according to fine aggregate standard and reviewed strength Properties.

• Korean Journal of Adult Nursing
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• v.19 no.3
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• pp.339-352
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• 2007

Purpose: The purpose of this study was to investigate the effect of weight control program on body composition(body mass index and waist-hip ratio), blood pressure, serum lipids(total cholesterol, triglyceride, high density lipoprotein and low density lipoprotein) and self-regulation behavior in obese college women. Methods: Forty seven obese subjects were divided into experimental(22) and control(25) groups. The weight control program lasting 12 weeks consisted of a traffic-light diet, jumping-rope exercises, and behavior modification methods with e-mail counseling. The data were collected from 29 March to 17 September of 2004. The variables were assessed before and after intervention for 12 weeks in two groups. Then, those were repeated after a 12 week suspension of intervention in the experimental group. The data were analysed by the SPSS computer program. Results: BMI, HDL, LDL and self-regulation behavior levels showed significant differences between the experimental and control groups. While there were no significant differences in waist-hip ratio, blood pressure, total cholesterol and triglyceride. Conclusion: The weight control program had a positive effect on obese college women, and can be used to control obesity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.6
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• pp.1194-1202
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• 2002

A study on the topology optimization of a multi-spectral camera for space-use is presented. The optimization is carried out under self-weight and polishing pressure loading. A multi-spectral camera for space-use experiences degradation of optical image in the space, which can not be detected on the optical test bench on the earth. An optical surface deformation of a primary mirror, which is a principal component of the camera system, is an important factor affecting the optical performance of the whole camera system. In this study, topology optimization of the primary mirror of the camera is presented. As an objective function, a measure of Strehl ratio is used. Total mass of the primary mirror is given as a constraint to the optimization problem. The sensitivities of the objective function and constraint are calculated by direct differentiation method. Optimization procedure is carried out by an optimality criteria method. For the light-weight primary mirror design, a three dimensional model is treated. As a preliminary example, topology optimization considering a self-weight loading is treated. In the second example, the polishing pressure is also included as a loading in the topology optimization of the mirror. Results of the optimized design topology for the mirror with various mass constraints are presented.