• Journal of The Korean Astronomical Society
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• v.41 no.6
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• pp.163-172
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• 2008

Using the spectral data in the 3700 to $10050{\AA}$ wavelength range secured with the Hamilton Echelle Spectrograph (HES) at the Lick observatory, we have investigated the expansion velocities and the physical conditions of the elliptical planetary nebula NGC 6803. Various forbidden and permitted lines, e.g. HI, HeI, HeII, [OIII], [NII], [ArIII], and [SII], indicate complicated but systematic physical conditions variation: electron temperatures $T_{\varepsilon}\;{\sim}\;9000$ - 11000 K and electron number densities $N_{\varepsilon}\;{\sim}\;2000$ - $9000\;cm^{-3}$. The line profile analysis of these ions also indicates the systematic change or the acceleration of the expansion velocities in the range of 10 - $22\;km\;s^{-1}$. We show that the velocity gradient and physical condition found in various ions are closely related to the prolate ellipsoidal structure of NGC 6803. The expansion velocity and the ionic abundance of $O^{2+}$ were derived based on the OII and [OIII] lines. In spite of the discrepancy of ionic abundances derived by the two cases and their line profiles, the expansion velocities of them agree well. We find that the ratios of the red to blue line component of the HeII & OII lines are different from those of the [OIII] or other forbidden lines that indicates a possible involvement of emission of HeII & OII lines. This subtle difference and the different physical condition of the lines are likely to be caused by the elongated geometry and the latitude dependence of the emission zone.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.39.2-39.2
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• 2017

Over the last decade, deep studies of nearby galaxies have led to the discovery of vast stellar envelopes that are often rich in substructure. These components are naturally predicted in models of hierarchical galaxy assembly, and their observed properties place important constraints on the amount, nature, and history of satellite accretion. One of the most effective ways of mapping the peripheral regions of galaxies is through resolved star studies. Using wide-field cameras equipped to 8 m class telescopes, it has recently become possible to extend these studies to systems beyond the Local Group. Located at a distance of 3.6 Mpc, M81 is a prime target for wide-field mapping of its resolved stellar content. In this talk, we present the detailed results from our deep wide-field imaging survey of the M81 group with the Hyper Suprime-Cam (HSC), on the Subaru Telescope. We report on the analysis of the structures, stellar populations, and metallicities of old dwarf galaxies such as NGC3077, IKN, KDG061, as well as young stellar systems such as Arp's Loop and Holmberg IX. Several candidates for yet-undiscovered faint dwarf galaxies and young stellar clumps in the M81 group will also be introduced. The peculiar galaxy NGC3077 has been classified as the irregular galaxy. Okamoto et al. (2015, ApJ 809, L1) discovered an extended halo structure with S-shape elongated tails, obvious feature of tidal interaction. With a help of numerical simulation by Penarrubia et al. (2009, ApJ 698, 222), we will demonstrate that this tidal feature was formed during the latest close encounters between M81, M82, and NGC 3077, which induced star formation in tidally stripped gas far from the main bodies of galaxies. It is not clear whether the latest tidal interaction was the first close encounters of three galaxies. If NGC3077 is still surrounded by the dark matter halo, it implies that NGC3077 has undergone the first tidal stripping by larger companions. Kinematic studies of inter galactic globular clusters and planetary nebulae would tell us the past history of tidal interaction in this group of galaxies.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.5
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• pp.447-456
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• 1987

The osteological development of the larvae and juveniles of Prognichthys agoo was examined on the laboratory-roared materials of 5.06-20.01 mm in mean total length(MTL). Cranium, vertebrae, caudal skeleton, siloulder girdle bone, pelvic girdle bone, pterygiophore and jaw bones were descriued in detail to examine the sequences of ossification. Ossification of the cranium took place at ca. 5.06 mm of MTL in exoccipital, basioccipital, parasphenoid. Ossification of the visceral skeleton occurred in areas where active movements of bones were required, notably in the parts for feeding and respiration. Vertebrae began to develop from the anterior end and to ossify posteriorly. Neural and haemal spines of vertebrae ossified always prior to the corresponding centra. Urostyle bone developed as an elongated bone from the early larvae and ossified prior to the centra caudal part. In jaw bones, maxillary and a part of dentary appeared first at 5.06 mm of MTL and attained a fundamental structure at 9.30 mm of MTL. Ossification of all bones was nearly completed at ca. 20.01 mm of MTL.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.138-140
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• 2002

The spinal cord dose is the one of the limiting factor for the radiation treatment of the head & neck (H&N) or the thorax region. Due to the fact that the cord is the elongated shaped structure, it is not an easy task to maintain the cord dose within the clinically acceptable dose range. To overcome this problem, the spinal cord partial block technique (PBT) with the dynamic Multi-Leaf Collimator (dMLC) has been developed. Three dimension (3D) conformal beam directions, which minimize the coverage of the normal organs such as the lung and the parotid gland, were chosen. The PBT field shape for each field was designed to shield the spinal cord with the dMLC. The transmission factors were determined by the forward calculation method. The plan comparisons between the conventional 3D conformal therapy plan and the PTB plan were performed to evaluate the validity of this technique. The conformity index (CI) and the dose volume histogram (DVH) were used as the plan comparison indices. A series of quality assurance (QA) was performed to guarantee the reliable treatment. The QA consisted of the film dosimetry for the verification of the dose distribution and the point measurements. The PBT plan always generated better results than the conventional 3D conformal plan. The PBT was proved to be useful for the H&N and thorax region.

• Applied Microscopy
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• v.19 no.2
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• pp.27-42
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• 1989

The forming process of scale and socket of Pieris rapae L. during in 30 hr. pupa to in adult was morphologically investigated with scanning electron microscopy and transmission electron microscopy. 1. The scale forming cells which were distinguished from other epidermal cells were first observed in 30 hr. pupa. In the aspect that scale forming cell beared some morphological relations to socket forming cells and in the distribution of its organelles, scale forming cell was divided into three regions-basal region in which nucleus located, neck region which was surrounded by socket forming cells and scale region that was the cytoplasmic projection region over the wing surface. In process of the development of scale forming cell neck region and scale region were extended into the molting space and at this time, the changes of surface structure of scale region have occurred initially. 2. There was a more distinct process that scale region changed into the scale. Scale region which was first originated as clublike projection of the cell body was subsequently elongated and flattened out by broadening of the cytoplasm. After that, in the surface of scale were formed longitudinal ridges and microribs. In the late pupa, the cytoplsam of scale region have autolyzed by lysosome-like bodies and at length, scale which had air spaces, trabecula, pigment granules, longitudinal ridges and transverse ridges. 3. The major protion of socket forming cell located beside neck region of scale forming cell under the wing surface but the processing portion of the cell lay over the wing surface, suggesting that socket forming cells have actively processing. In extending to the molting space of neck and scale region, socket forming cells developed to the molting space and constructed socket.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.108-120
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• 2017

Modern watermelon cultivars (Citrullus lanatus [Thunb.] Matsum.& Nakai var. lanatus) have fruits with diverse phenotypes, including fruit shape, rind patterns, and flesh color. Molecular markers enable efficient selection of plants harboring desirable phenotypes. In the present study, publicly available DNA markers tightly linked to fruit shape, rind stripe pattern, and flesh color were evaluated using 85 watermelon accessions with diverse fruit phenotypes. For fruit shape, the dCAPS SUN - Cla011257 marker revealed an 81% of marker - trait match for accessions with elongated or round fruits. For rind stripe pattern, the SCAR wsb6-11marker was effective for selecting Jubilee-type rind pattern from other rind patterns. For flesh color, the Clcyb.600 and Lcyb markers derived from a mutation in the Lycopene ${\beta}$ - cyclase (Lcyb) gene, were effective at selecting red or yellow flesh. Forty-eight accessions possessing diverse fruit - related traits were selected as a reference array and their genetic relationships assessed using 16 SSR markers. At a coefficient of 0.11, the 48 accessions grouped into two major clades: Clade I and Clade II. Clade I subdivided further into subclades I - 1 and I - 2 at a coefficient of 0.39. All accessions with colored flesh were classified into Clade I, whereas those with white - flesh were classified into Clade II. Differences in fruit traits between subclades I - 1 and I - 2 were observed for rind pattern and fruit color; a majority of the accessions with Crimson-type striped or non-striped rind were grouped together in subclade I - 1, while most accessions in subclade I - 2 had a Jubilee - type rind stripe pattern. These results imply that reference array watermelon accessions possess distinguishable genetic structure based on rind stripe pattern. However, no significant grouping pattern was observed based on other fruit-related traits.

• Polymer(Korea)
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• v.26 no.4
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• pp.468-476
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• 2002

Oxy-PAN fiber prepared from the preoxidation and saponification of raw PAN fiber is known to elongate and contract when immersed in basic and acidic solutions, respectively. In this study, about 30% elongation in NaOH solution and 30∼50% contraction in HCl solution have been observed. In mechanical test, the mechanical properties of oxy-PAN fiber in the contracted state was stronger than that in the elongated state. These behaviors and mechanical properties are compared to those of living muscle and linear actuator. The change of length in NaOH and HCl solutions is due to switching between a hydrophilic and a hydrophobic structure. Other reasons are exchange of ion and water in/out of oxy-PAN fiber, and osmotic pressure difference associated with relevant ions. Much studies are needed to clarify the effective factors on but the oxy-PAN fiber's elongation/contraction behavior and mechanical properties, but the oxy-PAN fiber perpared in our laboratory has a sufficient potential for application as artificial muscle and linear actuator.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.5
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• pp.440-446
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• 2012

A twisted cylinder has been newly designed by rotating the elliptic cross section along the spanwise direction in order to reduce the drag and vorticies in wake region. The flow around the twisted cylinder at a subcritical Reynolds number (Re) of 3000 is investigated to analyze the effect of twisted spiral pattern on the drag reduction and vortex suppression using large eddy simulation (LES). The instantaneous wake structures of the twisted cylinder are compared with those of a circular and a wavy cylinder at the same Re. The shear layer of the twisted cylinder covering the recirculation region is more elongated than that of the circular and the wavy cylinder. Successively, vortex shedding of the twisted cylinder is considerably suppressed, compared with those of the circular and the wavy cylinder. Consequently, the mean drag coefficient and the fluctuating lift of the twisted cylinder are less than those of the circular and the wavy cylinder.

• Korean Journal of Materials Research
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• v.23 no.1
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• pp.41-46
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• 2013

The microstructural evolution of AA1050/AA6061 complex aluminum alloy, which is fabricated using an accumulative roll-bonding (ARB) process, with the proceeding of ARB, was investigated by electron back scatter diffraction (EBSD) analysis. The specimen after one cycle exhibited a deformed structure in which the grains were elongated to the rolling direction for all regions in the thickness direction. With the proceeding of the ARB, the grain became finer; the average grain size of the as received material was $45{\mu}m$; however, it became $6.3{\mu}m$ after one cycle, $1.5{\mu}m$ after three cycles, and $0.95{\mu}m$ after five cycles. The deviation of the grain size distribution of the ARB processed specimens decreased with increasing number of ARB cycles. The volume fraction of the high angle grain boundary also increased with the number of ARB cycles; it was 43.7% after one cycle, 62.7% after three cycles, and 65.6% after five cycles. On the other hand, the texture development was different depending on the regions and the materials. A shear texture component {001}<110> mainly developed in the surface region, while the rolling texture components {011}<211> and {112}<111> developed in the other regions. The difference of the texture between AA1050 and AA6061 was most obvious in the surface region; {001}<110> component mainly developed in AA1050 and {111}<110> component in AA6061.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.365-372
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• 2008

Because stellerite, belonging to the zeolite group, is much less common mineral than any other minerals in Korea, little mineralogical study has been done so far. Stellerite occurs on open surfaces of fractured zones in the Yucheon Granite associated with flowery tourmaline, Chongdo, Gyeongsangbuk-do. Stellerite with $3{\sim}4\;mm$ length and $1{\sim}2\;mm$ width is characterized by an equigranular and euhedral form. Flat and elongated columnar crystals show well developed (010) face. Stellerite shows an intensive alteration process, possibly due to weathering or devitrification, as evidenced by microtextural analysis of Scanning Electron Microscope (SEM). Water loss occurs at $161^{\circ}C$ while dehydroxylation occurs at $467^{\circ}C$ causing decomposition of the structure afterward. From its textural observation, it is concluded that stellerite formed rapidly at small undercooling, precipitated from residual melt during the late stage with relatively constant chemistry.