• Journal of Fashion Business
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• v.6 no.2
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• pp.53-66
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• 2002

The spiral form, which comes from the organic form of natural phenomenon such as growth of creatures, has been used as a factor of formative shape in various fields of art until now. In conjunction herewith, this study intends to discover and express the life force and the formative beauty of natural substances with the organic spiral forms into clothing design, using various creating methods and materials such as Korean traditional paper. The natural substances with the spiral structure, such as seashells, land snails, passion flower, curled flower, growing chart of plants, Impatiens textori was used as subjects of the designs. The seven pieces of work were completed with attempts to develop aesthetic forms through the presentation techniques and methods via restructuring process of simplification, partial transformation and consolidation. Through such process the conclusion of this study is as follows: First, the nature, with unlimited possibilities, could be subject of human formative activities, leading to the creative world of formative art for designers. Second, adaptation of the spiral organic forms of nature into the contemporary clothing designs proved the motif as a source of inspiration of diverse subject, in recognition with its innate formative beauty as well as external shape. Third, design expressions via restructuring process of simplification, partial transformation and consolidation with designer's subjective point of view were adequate for the creations of contemporary fashion designs. Fourth, the Korean traditional paper, as a fine material for various shape according to the handling method, could be used appropriately in the contemporary clothing designs, expressing our aesthetic senses. Fifth and finally, expansion of the realm of formative expression of clothing through the development of possibilities of expression in contemporary clothing would enhance the creative possibilities of clothing design as formative art. In conclusion, the expression of clothing design as formative art was developed on the emphasis of re-creation of natural objects of the organic spiral form. For the future study, the applications of spiral form into everyday clothing designs, consolidating artistic senses and practical senses, are expected as opportunity of proposing developmental possibilities of the contemporary clothing designs.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.77.1-77.1
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• 2014

Galactic spiral arms are abundant with interesting gaseous substructures. It has been suggested that arm substructures arise from the wiggle instability (WI) of spiral shocks. While the nature of the WI remained elusive, our recent work without considering magnetic fields shows that the WI is physically originated from the accumulation of potential vorticity (PV) generated by deformed shock fronts. To elucidate the characteristics of the WI in more realistic galactic situations, we extend our previous linear stability analysis of spiral shocks by including magnetic fields. We find that magnetic fields reduce the amount of density compression at shocks, making the shock fronts to move toward the upstream direction. Magnetic tension forces from bent field lines stabilize the WI by prevent the generation of PV. When the spiral-arm forcing is F=5% of the centrifugal force of galaxy rotation, the maximum growth rate of the WI is found to be about 1.0, 0.4, and 0.2 times the orbital angular frequency for the plasma parameter ${\beta}=100$, 10, and 5, respectively. Shocks with ${\beta}=1$ are stable to the WI for F=5%, while becoming still unstable when F=10%.

• Korean Journal of Materials Research
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• v.28 no.2
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• pp.101-107
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• 2018

Li-incorporated ZnO thin films were deposited by using ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of Li-incorporation on the performance of ZnO thin films, the structural, electrical, and optical properites of the ZnO thin films were analyzed by means of X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), Hall effect measurement, and UV-Vis spectrophotometry with variation of the Li concentraion in the ZnO sources. Without incorporation of Li element, the ZnO surface showed large spiral domains. As the Li content increases, the size of spiral domains decreased gradually, and finally formed mixed small grain and one-dimensional nanorod-like structures on the surface. This morphological evolution was explained based on an anti-surfactant effect of Li atoms on the ZnO growth surface. In addition, the Li-incorporation changed the optical and electrical properties of the ZnO thin films by modifying the crystalline defect structures by doping effects.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.3-3
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• 2002

Many studies on crystal growth mechanisms of the hen egg-white lysozyme protein crystals have mainly performed by optical microscopy and atomic force microscopy (AFM). As results, two types of growth mechanisms, which are a two-dimensional nucleation mechanism and a spiral growth mechanism, were identified. However, there was no direct evidence of grown-in screw dislocations at the spiral sites. We first observed the screw dislocations in tetragonal lysozyme crystals using synchrotron X-ray topography. In addition, to confirm the characteristics of dislocations, we have observed some elastic constants in lysozyme crystals in terms of the sound velocity measurement by pulse echo methods. Tetragonal hen egg-white lysozyme crystals were grown by the concentration gradient method. The crystals were grown in test tubes, with an inner diameter of 8 ㎜ and 80 ㎜ in length, held vertically. The test tubes were kept at 23C for 2 weeks. The maximum size of crystals were 3×3×4 ㎟. The high quality crystals were examined by Laue topography with a water filter using synchrotron radiation. Figure is a X-ray topograph. Several straight screw dislocations were observed. We also determined Burgers vector to be a [110] direction. The measurement of sound velocity was performed by the digital signal processing method. the crystals were placed in stainless steel vessel, which was filled with lysozyme solution used for crystal growth. We observed the longitudinal sound velocity along the [110] direction in the tetragonal is obtained to be 1817 ㎧. Therefore, Young modulus and shear modulus were evaluated to be 2.70 Gpa and 1.02 Gpa, respectively, if we assumed Poisson ratio is 0.33. These results will be discussed at the meeting.

• Korean Journal of Microbiology
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• v.23 no.3
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• pp.223-229
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• 1985

We have previously isolated seven strains of spiral form bacteria, which have shown several similar characteristics to Leptospira from patient with epidemic pulmonary hemorrhagic fever and matural paddy water. Further studies have performed to characterize them. All of the isolated bacteria were aerobic, gram negative and spiral form and their growth were completely inhibited at temperature below $13^{\circ}C\;and\;50^{\circ}C$. In sensitivity test to drugs, the bacteria were resistant to the bile salts, 5-Fu and Amphotericine B, but sensitive to the 8-Azaguanine. The isolated bacteria as well as 5 serotypes of Leptospira interrogans reacted the patient sera and it was also shown that antisera from rabbit immunized with the isolated bacteria reacted with 5 serotypes of Leptospira interrogans. These results suggest that the isolated bacteria may belong to the genus Leptospira.

• The KSFM Journal of Fluid Machinery
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• v.12 no.5
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• pp.13-18
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• 2009

In this paper, it is intended to figure out the features and causes of the processes of creation, growth and disappearance of spiral-vortex-flow generated in Francis turbines generally. The spiral-vortex-flow generated in draft tubes of the Francis turbines is estimated to have negative effects on power plant structure and to the people inside the building as well as to lead to a low-frequency-vibration driven by sub-synchronous whirl vibration. Therefore, we intend to investigate how much the low-frequency-vibration has an influence upon the powerhouse structure and practice analyzing the effectiveness on the previously-introduced methods to reduce side-effects of sub-synchronous whirl vibration and finally we intend to show the optimal solutions through this paper.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.37.2-37.2
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• 2014

Gas in disk galaxies interacts nonlinearly with a underlying stellar spiral potential to form galactic spiral shocks. Numerical simulations typically show that these shocks are unstable to the wiggle instability, forming non-axisymmetric structures with high vorticity. While previous studies suggested that the wiggle instability may arise from the Kelvin-Helmholtz instability or orbit crowding of gas elements near the shock, its physical nature remains uncertain. It was even argued that the wiggle instability is of numerical origin, caused by the inability of a numerical code to resolve a shock that is inclined to numerical grids. In this work, we perform a normal-mode linear stability analysis of galactic spiral shocks as a boundary-value problem. We find that the wiggle instability originates physically from the potential vorticity generation at a distorted shock front. As the gas follows galaxy rotation, it periodically passes through multiple shocks, successively increasing its potential vorticity. This sets up a normal-mode that grows exponentially, with a growth rate comparable to the orbital angular frequency. We show that the results of our linear stability analysis are in good agreement with the those of local hydrodynamic simulations of the wiggle instability.

• The Journal of the Korean Society for Microbiology
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• v.21 no.2
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• pp.191-204
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• 1986

Leptospira isolated from the patients with so called epidemic pulmonary hemorrhagic fever were comparatively studied with standard strains obtained from ATCC. The specific aim of this study was to clarify the morphologic heterogeneity of the isolates, i. e., coexistence of spiral forms in both handness, right and left, rod and spherical forms in their population by comparing them with those of the ATCC strains. No differences between our strains and ATCC strains were noticed in their growth characteristics, responses to the culture media, temperature, antibiotics and antifungal agents. Furthermore, the morphologic heterogeneity had been repeatedly observed even in cultures of standard ATCC strains, which had been noticed in the cultures of bacteria isolated in this laboratory. The serologic analysis of our isolates demonstrated that the bacteria reacted with L. icterohaemorrhagiae and L. australis regardless their differences in time of isolation(1984, 1985). Thus, it was concluded that the spiral bacteria isolated in this laboratory are Leptospira of a new serovar which still remained to be determined. And the previous reports on the morphology of the Leptospira, which described that the Leprospira population has only spiral forms with right. handed coils might be reconsidered.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.173-175
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• 2003

At the low temperature of $950^{\circ}C$ the $\mu\textrm{m}$-sized whisker growth during the catalytic CVD of pyrolytic carbon from methane with $H_2$- and Ar-gas on quartz substrate with NiO powder was found in this work. In the preliminary study it was observed from pure methane pyrolysis without catalyst at the high temperature $1500~1700^{\circ}C$. If the growth whisker should be stopped at initial stage, about 20 min. of the methane pyrolysis, it would be nanosized whisker growth. The screw growth mechanism and unique mechanical properties of whisker for composites were also recognized. If the pyrolysis would be continued, we could found also spiral growth of whistlers with diameter of about 1, 5 mm. The large length of whisker was about 10 cm in 20 minute.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.31.2-31.2
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• 2017

The central regions of barred-spiral galaxies contain interesting gaseous structures such as dust lanes and nuclear rings with intense star formation. While our previous studies were useful in understanding the formation of these structures star formation history, they were limited to 2D isothermal galaxies in which the stellar disk and halo are modeled by fixed gravitational potentials. To study the effects of bar growth as well as the vertical dimension, we use the mesh-free hydrodynamic code named GIZMO and run 3D simulations by treating the stellar disk and halo as being live. We find that the new 3D models form the gaseous features similarly to the previous 2D models, although the detailed formation processes are quite different. For example, a ring has a large radius when it first forms and shrinks over time in the previous 2D models. In the 3D live-potential models, however, a ring forms small and grows in size with time. We present the results of the new simulations and discuss them in comparison with the previous 2D results.