• Communications of the Korean Mathematical Society
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• v.28 no.4
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• pp.857-863
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• 2013

In this paper, we prove that the total domination number of a $P_6$-free graph of order $n{\geq}3$ and minimum degree at least one which is not the cycle of length 6 is at most $\frac{n+1}{2}$, and the bound is sharp.

• Journal of Mechanical Science and Technology
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• v.19 no.9
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• pp.1753-1760
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• 2005

The pseudo spectral method is applied to the free vibration analysis of double-span Timoshenko beams. The analysis is based on the Chebyshev polynomials. Each section of the double-span beam has its own basis functions, and the continuity conditions at the intermediate support as well as the boundary conditions are treated separately as the constraints of the basis functions. Natural frequencies are provided for different thickness-to-length ratios and for different span ratios, which agree with those of Euler-Bernoulli beams when the thickness-to-length ratio is small but deviate considerably as the thickness-to-length ratio grows larger.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.6
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• pp.437-447
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• 2013

The fibula is one of the most useful sources for harvest of a vascularized bone graft. The fibula is a straight, long, tubed bone, much stronger than any other available bone that can currently be used for a vascularized graft. It has a reliable peroneal vascular pedicle with a large diameter and moderate length. There is a definite nutrient artery that enters the medullary cavity, as well as multiple arcade vessels, which add to the supply of the bone through periosteal circulation. The vascularized fibula graft is used mainly for long segment defects of the long tubed bone of the upper and lower extremities. It can provide a long, straight length up to 25 cm in an adult. The fibula can be easily osteotomized and can be used in reconstruction of the curved mandible. Since the first description as a vascularized free fibula bone graft by Taylor in 1975 and as a mandibular reconstruction by Hidalgo in 1989, the fibula has continued to replace the bone and soft tissue reconstruction options in the field of maxillofacial reconstruction. For the better understanding of a fibular free flap, the constant anatomical findings must be learned and memorized by young doctors during the specialized training course for the Korean National Board of Oral and Maxillofacial Surgery. This article reviews the anatomical basis of a fibular free flap with Korean language.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.7-15
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• 2002

The essential oil free needles, which were left after distillation of essential oil from various coniferous needles, were fermented with food waste organics in order to use as compost and roughage. Microorganisms for the fermentation were selected from domestic sources such as swine compost, bark compost, and kimchi, etc, and consisted of aerothermophilic bacteria and actinomycetes. The weight reduction ratio of food waste organics treated with the microorganisms was 90% after 30 days treatment, and the fermentation temperature was kept at approximately $45^{\circ}C$. The compost process was really slow due to chemical compounds derived from needles, and it finally took 60 days for complete compost. When 10% of needle compost was mixed with soil for radish growth, the growth indicators such as leaf length and root weight were increased compared with control, while root weight, root width, and root length were inhibited on the addition of 20% needle compost. The nutrient value and digestibility ratio of various essential oil free needles as roughage for ruminant animals were evaluated. The ratio of crude protein for essential oil free needles from Korean pine(Pinus koraiensis) was 10.02%, which was higher than those of rice straw(5.48%) and corn(9.00%). The digestibility ratios of essential oil free needles from Sawara cypress(Chamaecwaris pislfera), Korean pine(Pinus koraiensis), and Japanese Red Pine(Pinus densiflora) was 53%, 34%, 34%, respectively, indicating that those essential oil free needles were considered as excellent roughage.

• Wind and Structures
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• v.29 no.1
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• pp.75-84
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• 2019

A steady slot suction near the free-end leading edge of a finite-length square cylinder was used to control its aerodynamic forces and vortex-induced vibration (VIV). The freestream oncoming flow velocity ($U_{\infty}$) was from 3.8 m/s to 12.8 m/s. The width of the tested cylinder d = 40 mm and aspect ratio H/d = 5, where H was the height of the cylinder. The corresponding Reynolds number was from 10,400 to 35,000. The tested suction ratio Q, defined as the ratio of suction velocity ($U_s$) at the slot over the oncoming flow velocity at which the strongest VIV occurs ($U_{\nu}$), ranged from 0 to 3. It was found that the free-end slot suction can effectively attenuate the VIV of a cantilevered square cylinder. In the experiments, the RMS value of the VIV amplitude reduced quickly with Q increasing from 0 to 1, then kept approximately constant for $Q{\geq}1$. The maximum reduction of the VIV occurs at Q = 1, with the vibration amplitude reduced by 92%, relative to the uncontrolled case. Moreover, the overall fluctuation lift of the finite-length square cylinder was also suppressed with the maximum reduction of 87%, which occurred at Q = 1. It was interesting to discover that the free-end shear flow was sensitive to the slot suction near the leading edge. The turbulent kinetic energy (TKE) of the flow over the free end was the highest at Q = 1, which may result in the strongest mixing between the high momentum free-end shear flow and the near wake.

• Journal of the Korean Society of Costume
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• v.30
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• pp.201-210
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• 1996

The perpose of this study is to compare and to analyze the characters of the shape of up-per arm and armscye line between young and aged women. The subjects were measured with the Mar-tin's anthropometer and with free curve ruler. 10 items in the shape of upper arm were measured and 16 items in the shape of armscye line measured indirectly based on the measured shape taken from the subjects with free curve ruler and both date were analyzed. Mean standard deviation f-test factor analysis were performed for the statistical analysis of the date. The main results were as follows: 1) The shape of the upper arm is long and narrow in youg women compared with aged. 2) The length of the axilla of the aged women were longer than that of young women. 3) There are significant differences young and aged women on the shape of armscye line. THe length of from the front point of axilla to shoulder point width and depth of the shape of the armscye line length of axilla of aged women were longer than that of young. but the length of from the back point of axilla to shoulder point of yyoung women was longer than aged. 4.) The front point of axilla was existed lower than back point of axilla in aged women while front point of axilla was existed higher than the back point in young. 5) Through the factor analysis two factors were obtained from the shape of the upper arm and five factors from the shape on armmscye line in both groups. Factor compornents in the shape of the up per arm were length width and girth of that and in the shape of the armscye line were width and length of upper and lower back and front part of the shape of the armscye line depth of the axilla. he items in the same factor were resemble each other between two groups.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.4
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• pp.361-371
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• 1983

The turbulent structures of the free plane jet and two dimensional impinging jet are investigated experimentally. In order to get the two dimensional jet, the contour of the cubic equation suggested by Morel is used for a contracting nozzle. A linearized constant-temperature hot-wire anemometer is used for measurement. Mean velocities and turbulent intensities are measured along the centerline of the jet. Jet halp width spatial double velocity correlation coefficients and integral length scales are obtained. It is established that the free plane jet is truly self-preserving about 40 slot widths downstream of the nozzle. The experiments for the impinging jet are carried out at four different impingement wall locations within the self-preserving region of the free plane jet, and comparing the results with that of free plane jet, the mean velocity is changed in the region of 0.25H and turbulent intensities are affected in the region of 0.2H from the wall, respectively, where H means the distance between the nozzle exit and the wall.

• Archives of Reconstructive Microsurgery
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• v.6 no.1
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• pp.80-86
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• 1997

The lateral arm flap was reported first by Song et al. in 1982, and Katsaros and colleagues described an anatomic study and clinical cases in 1984. This flap is thin, has relatively constant vascular anatomy, and provides relatively acceptable scar at the donor site. Despite its many advantages its wide application has been limited by its short vascular pedicle with small diameter of lumen, and its small skin paddle. We studied its anatomical structure to get longer length of vascular pedicle, wide diameter and thinner part of flap beyond the lateral condyle through 6 fresh cadaver dissection and dye injection study. We experienced 21 cases of lateral arm free flaps and 26 cases of forearm free flaps from May, 1992 to January, 1996. We compared its usefulness with forearm free flaps in the aspects of donor morbidity, operative factors, quality of flap, and versatility. In conclusion, lateral arm flap can replace the role of forearm flap in most cases so that patient's donor morbidity can be reduced especially in the women.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.263-271
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• 2001

Blast-vibration tests were carried out to determine the effects of the number of free face on the level of blast vibration. Frequency chatacteristics were also examined by using FFT analysis. To check the effects of the number of free face, charge weight per delay, drilling length, burden and space were applied uniformly and the number of free face was only changed from one to four. The results from tests were checked by regression analysis and K-value.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2297-2307
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• 1995

An experimental study on the structure of a separated shear layer downstream of the backward-facing step has been performed by examining mean flow and turbulent quantities in terms of free stream turbulence. When free stream turbulence exists, the entrainment rate of the separated shear layer and the flow rate in the recirculation region are enhanced, resulting in shorter reattachment length. The production and diffusion terms in the turbulent kinetic energy balance are shown to increase more than the dissipation term does. Rapid decrease of the pressure-strain term in the shear stress balance implies the enhancement of the three-dimensional motion by free stream turbulence.