• International Journal of Aeronautical and Space Sciences
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• v.12 no.4
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• pp.365-370
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• 2011

This paper presents the air-to-air missile autopilot design for a $180^{\circ}$ heading reversal maneuver during boost-phase. The missile's dynamics are linearized at a set of operating points for which angle of attack controllers are designed to cover an extended flight envelope. Then, angle of attack controllers are designed for this set of points, utilizing a pole-placement approach. The controllers' gains in the proposed configuration are computed from aerodynamic coefficients and design parameters in order to satisfy designer-chosen criteria. These design parameters are the closed-loop frequency, damping ratio, and time constant; these represent the characteristics of the control system. To cope with highly nonlinear and rapidly time varying dynamics during boost-phase, the global gain-scheduled controller is obtained by interpolating the controllers' gains over variations of the angle of attack, Mach number, and center of gravity. Simulation results show that the proposed autopilot design provides satisfactory performance and possesses good [ed: or "sufficient" or "excellent"] capabilities.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.75-81
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• 2003

This study evaporates ZnO layer thickness differently with RF sputtering method on Si Wafer(n-100). This study is performed to examine the characteristics of photon energy and dielectric loss according to the thickness of ZnO and increase the reliability and reproduction of ZnO thin film. It is confirmed that the variation of electric Permittivity by frequency is resulted from the formation of particles within thin film, the particle size and the polarization on grain boundary. Peak of electric Permittivity value of thin film has slower and less value in early low wavelength by the coulomb force involved in carrier combination according to the increase of frequency. Reversal of electric Permittivity values is induced by dipole polarization shown in the dielectric of thin film. Complex electric constant $({\varepsilon}_1{\varepsilon}_2)$ has larger peak values as it’s thickness is thinner and then it is larger according to the increase of frequency. Electric Permittivity by photon energy has large value in imaginary number and is reduced exponentially by the increase of carrier density according to that of photon energy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.73-79
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• 2002

This study evaporates ZnO layer thickness' differently with RF sputtering method on Si Wafer(n-100). This study is performed to examine the characteristics of photon energy and dielectric loss according to the thickness of ZnO and increase the reliability and reproduction of ZnO thin film. It is confirmed that the variation of electric Permittivity by frequency is resulted from the formation of particles within thin film, the particle size and the polarization on grain boundary. Peak of electric Permittivity value of thin film has slower and less value in early low wavelength by the coulomb force involved in carrier combination according to the increase of frequency. Reversal of electric Permittivity values is induced by dipole polarization shown in the dielectric of thin film. Complex electric constant $({\varepsilon}_1,{\varepsilon}_2)$ has larger peak values as it's thickness is thinner and then it is larger according to the increase of frequency. Electric Permittivity by photon energy has large value in imaginary number and is reduced exponentially by the increase of carrier density according to that of photon energy.

• Journal of the Korea Fashion and Costume Design Association
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• v.15 no.2
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• pp.65-75
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• 2013

As a typical subculture, Goth exercises influence on our culture in broad areas. Features of Gothic style, such as dark aesthetics, images of death and fear, and erotic horrification, emerged as attractive themes to contemporary fashion designs. Based on the dark attraction of black color, Goth fashion creates mysterious and fantastic atmosphere as well as grotesque and horrifying mood. 'Hallyu' or Korean wave is a term to describe the phenomenon of fervently loving Korean popular culture. As the fast spreading Hallyu is strongly engraved through the visually conspicuous fashion, we can say that fashion plays important role in diffusing Hallyu. In addition, a number of analyses and researches on the Hallyu, including K-pop, have been conducted, while concentrating keen interest in fashion of Hallyu K-pop stars. Accordingly, this study is designed to examine relations between fashion of K-pop stars and Goth fashion after analyzing features of Hallyu and K-pop and contemplating Goth fashion. Namely, this study will analyze various Goth images shown in K-pop fashion, which is the core of Hallyu, and identify aesthetic features of Goth shown in the fashion of K-pop stars. An investigation and analysis of the Goth images shown in the fashion of K-pop stars identifies the following features : a black aesthetic, eroticism, defiance, reversal of gender identity, and mystery.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.47.2-47.2
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• 2021

Focusing on both small separations and baryonic acoustic oscillation scales, the cosmic evolution of the clustering properties of peak, void, wall, and filament-type critical points is measured using two-point correlation functions in ΛCDM dark matter simulations as a function of their relative rarity. A qualitative comparison to the corresponding theory for Gaussian random fields allows us to understand the following observed features: (i) the appearance of an exclusion zone at small separation, whose size depends both on rarity and signature (i.e. the number of negative eigenvalues) of the critical points involved; (ii) the amplification of the baryonic acoustic oscillation bump with rarity and its reversal for cross-correlations involving negatively biased critical points; (iii) the orientation-dependent small-separation divergence of the cross-correlations of peaks and filaments (respectively voids and walls) that reflects the relative loci of such points in the filament's (respectively wall's) eigenframe. The (cross-) correlations involving the most non-linear critical points (peaks, voids) display significant variation with redshift, while those involving less non-linear critical points seem mostly insensitive to redshift evolution, which should prove advantageous to model. The ratios of distances to the maxima of the peak-to-wall and peak-to-void over that of the peak-to-filament cross-correlation are ~2-√~2 and ~3-√~3WJ, respectively, which could be interpreted as the cosmic crystal being on average close to a cubic lattice. The insensitivity to redshift evolution suggests that the absolute and relative clustering of critical points could become a topologically robust alternative to standard clustering techniques when analysing upcoming surveys such as Euclid or Large Synoptic Survey Telescope (LSST).

• Journal of Korea Foundry Society
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• v.24 no.1
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• pp.52-59
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• 2004

Microstructure and mechanical properties of ductile cast iron were investigated in terms of diameter change of samples that gives rise to modify the microstructure due to different cooling rate in the continuous casting process. The chemical composition used in this study was GCD 400 grade. From the microstructural observation, we have found a large number of graphite with small size in diameter which is comparable to the microstructure of the sample produced by conventional sand casting. The major reason of this would he due to high cooling rate. In the sample with 26 mm in diameter, the microstructure was composed of pearlite, iron carbide, and graphite. In the samples with 60 and 100 mm in diameter, however, we have observed a dissimilar microstructure that consisting of ferrite and graphite. Concerning the mechanical property, the sample with 26 mm in diameter showed higher hardness and strength compared to those samples with 60 and 100 mm in diameter. The result obtained for ductility appeared a reversal. Much more works such as inoculation, process design and chemical composition would be required in order to have a sound product even in a small diameter of samples.

• Journal of Welding and Joining
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• v.8 no.4
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• pp.46-57
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• 1990

TMCP steel manufactured by controlled rolling followed by accelerated cooling process is known to have extra-ordinary mechanical properties such as tensile strength and toughness. However, there is much uncertainty about the fatigue fracture characteristics, especially, in the welded state of this steel. In case of this steel, the softening zone by welding is generated in heat affected zone in contrast with the case of conventional normalized high strength steel. This softening zone is considered to play significant roles in low cycle fatigue fracture of the welded part of this steel. In this paper, the low cycle fatigue behaviors of TMCP steel were inspected in as-received and welded state using the smooth specimen. The fatigue life-time was seperately investigated on the basis of failure of the specimen and crack initiation which is detected by differential strain method. Moreover, the low cycle fatigue characteristics of TMCP steel were quantitatively compared with those of the conventional normalized steel of same strength level.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.329-334
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• 2002

This study evaporates TiO$_2$ layer thickness differently with RF sputtering method on Si Wafer(n-100). Thin film is made with the structure of Si+TiO$_2$ and Si+TiO$_2$+Al by evaporating TiN which is used as Antireflection of superintegrated semiconductor integrated circuit with Photo Catalyst. The research is performed to increase the characteristics of photon energy according to TiO$_2$ thickness and the reliability and reproducibility of TiO$_2$ thin film. Reversal of electric Permittivity values is induced by dipole polarization shown in the dielectric of thin film. Complex electric constant ($\varepsilon$$_1$, $\varepsilon$$_2$) has larger peak values as it's thickness is thinner and then it is larger according to the increase of frequency. Electric Permittivity by photon energy has large value in imaginary number and is reduced exponentially by the increase of carrier density according to that of photon energy.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.9
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• pp.780-789
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• 2007

Lock-on phenomenon in the wake of a circular cylinder is investigated at the Reynolds number of 360 using direct numerical simulation (DNS). To induce lock-on, a streamwise velocity perturbation with a frequency of twice the natural shedding frequency is superimposed on the free stream velocity. The Reynolds stress distributions are investigated to analyze the streamwise force balance acting on the recirculation region and the results are compared with the previous experimental result. When the lock-on occurs, the pressure force on the recirculation region is shown to increase mainly due to the reversal of the Reynolds shear stress distribution, which is consistent with our previous results using PIV measurement. It is also shown that, with the lock-on, the strength of the primary vortices increases whereas that of the secondary vortices decreases significantly. Further, under the lock-on condition the wavelength of the secondary vortices increases by as much as 2.5 times.

• Journal of Nutrition and Health
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• v.19 no.5
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• pp.333-341
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• 1986

Several aspects including physical development, reflex acquistion, neuromotor development and learning behavior at Y water maze were compared at the progeny of rats fed low 91.2mg/kg diet) or adequate leves(22mg/kg diet 0 of pyridoxine during growth, gestation, lactation, and adult period. Physical development and development of reflexes (righting reflex, cliff avoidance, negative geotaxis, palmar grasp, and startle reflex to sound) appeared different between control and deficient groups but not significantly. At the 2nd week, rats spent more time in supported standing during 6 minute period was longer in the control then the deficient groups. In the Y-water maze position reversal test, learning ability as judged by the number of errors was not different among three groups, but the rats in supplemented group(DC) reached the escape platform in significantly shorter time than the other two groups, which may suggest their emotional instability. In the visual discrimination test, the performance of rats from the supplemented group had the lower errors than the other groups on the early test days. but as the testing period progressed, the performance of rats in the supplemented group became inferior to those of the control and deficient groups. The performance of control group became superior to that of the deficient group.