• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.275-282
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• 2002

We derived analytic formulae for the correction of spherical aberration, coma, and axial color of a two-components lens system consisted of a cemented doublet and a singlet by using the thin lens approximation. The correction formulae were applied to design a telephoto lens system. We examined two kinds of glass combinations in the design, one was crown-flint-crown combination and the other was flint-crown-flint combination. We found two kinds of achromatic aplanat solutions in the crown-flint-crown combination. For the case of flint-crown-flint combination, there were also two kinds of solutions, but their configurations are not useful in practice.

• Journal of the Korean Society of Costume
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• v.30
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• pp.153-166
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• 1996

The purpose of this paper is to examine the Ethnic Fashion which is influenced by the Anti-Fashion in 1960s. Anti-Fashion as Hippie style had an effect on high fashion in the 60s-70s and which was restored in the early 90s are ethnic and folk-lore style. The influence that the Anti-Fashion has had on the Ethnic Fashion is summarized as follows. At the Ethnic Fashion in 60s-70s: First Europian romantic style that is velvet doublet breecheese race cuffs ruffle flounce race jabbot embrioderd blouse frilled blouse Victorian mode and Pre-Raphaello style. Second handicraft ornaments style & peasant style what are embroidery weaving variaty ornaments tie-dye patch work smocking beads & bell paisely print peasant blouse dundle skirt long skirt to clinging layered look floral print dress and shepherd-ness style. Third folklore style that is Oriental mao-suit harem pants & Indian pants caftan monk robe Afgan vest burnoos dhoti pants Hindu robe Red Indian fringe head band feather ornaments Red indian embroidery & weaving body painting gaucho poncho and serapi. At the Ethnic Fashion in 90s.: First Europian classical romantic style that is Victorian style Pre-Raphaello style ruffle & race decorations and velvet materials. Second peasant look& handicraft orna-ments what are floral print long skirt to cling-ing uneven stitches top stitchings patch work embroidery crochet and tie-dye. Third folklore style that is Red Indian style South East mode is sarong skirt & Nheru jacket Tibet & Mongolian style South America style and gypso style.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.35-44
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• 2007

In this study was made the flutter analysis for the export model of Firefly(Bandi-ho), the small canard aircraft. Stiffness model based on internal load generation finite element model was generated. Mass model based on the weight DB for weight control was generated. Aerodynamic model based on Doublet Lattice Method was generated. Preliminary flutter analysis was made. Based on it, major vibration modes are identified and experimentally obtained via the ground vibration test. The obtained normal mode frequencies were used to correlate the finite element model. Flutter analysis was made again and major flutter mechanisms were summarized. The most important flutter root was identified as a coupled root between rigid body roll mode and anti-symmetric wing pitching mode.

• Journal of the Korean Society of Costume
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• v.40
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• pp.171-180
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• 1998

This is a study on the Men's Underclothes of Renassience Ages. The changes associated with the Tudor regime were sufficiently profound to afect the nature and purpose of underclothes. Ceasing to be merely a layer serving to protect the skin, they now began to assist the external costume of both sexes in expressing class distinction. In order to attract still greater attention, the edge of the shirt was ruffled at the neck, a decoration which soon developed into a separate accessory, the ruff. The waistcoat, which originally was an under-garment, was shown, when the doublet was taken off, en deshabille. Thus we see that for men in the sixteenth century the undergarment was no longer an obscure drudge, but was promoted to serve in the general mode of expressing what the whole costume so extravagantly announced ; and likewise to share in that extreme degree of the social superior. The pinched waist of both sexes was not so much for sex attraction, but to signify social superiority. In the period under considera-tion, then, from the Tudors to the end of the Jacobeans, the new function of underclothes was much the same for both sexes ; to exploit the grandeur of the costume as evidence of rank, and only by that indirect method to add to the wearer's sex attractions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.28-33
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• 2005

Nonlinear aeroelastic characteristics of a two dimensional typical section model with bilinear plunge spring are investigated. Doublet-point method(DPM) is used for the calculation of supersonic unsteady aerodynamic forces which are approximated by using the minimum-state approximation. For nonlinear flutter analysis structural nonlinearity is represented by an asymmetric bilinear spring and is linearized by using the describing function method. The linear and nonlinear flutter analyses indicate that the flutter characteristics are significantly dependent on the frequency ratio. From the nonlinear flutter analysis, various types of limit cycle oscillations are observed in a wide range of air speeds below or above the linear flutter boundary. The nonlinear flutter characteristics and the nonlinear aeroelastic responses are investigated.

• Journal of Fashion Business
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• v.6 no.6
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• pp.43-55
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• 2002

This study intends to consider the characteristics of Tudorian costume and find out how the thoughts and cultures in those days had influences on the costume trends of low and middle class. In terms of the Tudorian costume which generated new cultural mainstreams along with blossomed civil culture, this study focuses on the characteristics and trends of costume at low and middle class, which have been little addressed in studies on western costume history or related fields, turning from the costume of upper class based on wealthy noblemen who showed off its dignity and authority along with jewelry and gorgeous ornamental craftsmanship. This study used related pictures, museum material and other literatures as its reference. It first looked into the general characteristics of western costume and considered the characteristics of costumes popularized in professionals at middle class such as apprentice, yeomen and low-class people. Professional or other middle class almost typically used to wear tunic, doublet, shirts, coat or long gown. Black was mainly used as clothes color. Similarly to upper class, silk or velvet was very often used as material. People at low class enjoyed wear costumes with simple and easy style for working. They also preferred natural color and cotton or wool as material. This study intended to find out which type of costumes people at low and middle class enjoyed wearing, rather than compare costume between such two classes.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.104-109
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• 2004

On this paper study is concentrated on the breakup and atomization characteristics of spray formed by impinging jet injectors(like-doublet) used in liquid rocket engine(LRE). On the process of breakup and atomization, injection velocity and ambient gas pressure are the main parameters, so that these are used as variables that specify the experimental condition. Injection velocity varied from 3m/s to 30m/s and ambient gas pressure changed from 0.1MPa to 4.0MPa with nitrogen gas. As results, measured physical quantities decreased with increasing injection velocity and ambient gas pressure. But the decreasing ratios are different from those of the theory.

• The Journal of the Acoustical Society of Korea
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• v.21 no.2E
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• pp.71-80
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• 2002

This paper suggests the Cardioid beamforming algorithm of the doublet sensors employing DIFAR (directional frequency analysis and recording) sensor signals in the frequency domain. The algorithm enables target bearing estimation using the signals from directional sensors. The algorithm verifies its applicability by successfully estimating bearings of a target projecting ten narrow-band signals in shallow water. The estimated bearings agree very well with those from GPS (global positioning system) data. Assuming the bearings from GPS data to be real values, the estimation errors are analyzed statistically. The histogram of estimation errors in each frequency have Gaussian shape, the mean and standard deviation dropping in the ranges -1.1°∼ 6.7°and 13.3∼43.6°, respectively. Estimation errors are caused by SNR (signal to noise ratio) degradation due to propagation loss between the source and receiver, daily fluctuating geo-magnetic fields, and non-stationary background noises. If multiple DIFAR systems are employed, in addition to bearing, range information could be estimated and finally localization or tracking of a target is possible.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1706-1712
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• 2014

The OH($X^2{\Pi}$, ${\upsilon}^{\prime\prime}=0,1$) internal state distribution following the reaction of electronically excited oxygen atom ($O(^1D_2)$) with cyclo-$C_3H_6$ has been measured using laser-induced fluorescence, and compared with that following the reaction of $O(^1D_2)$ with $C_3H_8$. The overall characteristics of the OH internal energy distributions for both reactions were qualitatively similar. The population propensity of the ${\Pi}(A^{\prime})$ ${\Lambda}$-doublet sub-level suggested that both reactions proceeded via an insertion/elimination mechanism. Bimodal rotational population distributions supported the existence of two parallel mechanisms for OH production, i.e., statistical insertion and nonstatistical insertion. However, detailed analysis revealed that, despite the higher exoergicity of the reaction, the rotational distribution of the OH following the reaction of $O(^1D_2)$ with $C_3H_8$ was significantly cooler than that with cyclo-$C_3H_6$, especially in the vibrational ground state. This observation was interpreted as the effect of the flexibility of the insertion complex and faster intramolecular vibrational relaxation (IVR).

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.43.1-43.1
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• 2016

The duration of star formation activity is a key to understanding the formation process of star clusters. Although a number of astronomers have attempted to derive the underlying age spread in photometric diagrams with a variety of stellar evolutionary models, the resultant findings are subject to uncertainties due to intrinsic variability of pre-main sequence (PMS) stars, observational errors, difficulties in reddening correction, and systematic differences in adopted stellar evolutionary models. The distribution of Li abundance for PMS stars in a cluster could, on the other hand, provide an alternative way to estimate the age spread. In this study, a total of 134 PMS stars in NGC 2264 are observed with the high resolution multi-object spectrogragh Hectochelle attached to the 6.5m Multi Mirror Telescope. We have successfully detected Li ${\lambda}6708$ resonance doublet for 86 low-mass PMS stars. The Li abundance of the stars is derived from their equivalent width using a curves of growth method. After correction for non-LTE effects, the underlying age spread of 3 - 4 Myr is inferred from the Li abundance distribution of low-mass PMS stars. We suggest that NGC 2264 formed on a timescale shorter than 5 Myr given the presence of embedded populations.