• Journal of the Korean Society of Clothing and Textiles
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• v.12 no.1 s.26
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• pp.1-11
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• 1988

This study dealt with the Dopo, one of the representative ceremonial dress that acclasical scholar used after the middle of the period of the Chosun dynasty. This study represents the period of Dopo's formation and its origin, and the characteristics of the weary of Dopo in Young Dong Province Area is arranged by folkloric method on the base of the exisitng facilities. Dopo has worn since the middle of the period of the Chosun dynasty. It is the kind of Jig young Po that its back is cuffed for convenience and has another cloth as a ceremonial dress. It is thought to be one of the national customs pos formed by the mixture of the big sleeve type which is influenced by confusion life feeling. It seemed that the name of DoPo comes from the Jigchal, an ordinary dress of a high official in China, which is call Dopo. This Dopo is changed and received and so disappeared but it is still used such as ceremonial dress, the necessary articles for marriage of the bride, a bridegroom's liturgical vestments of a memorial service held on the anniversary of the death of a person, mourning dress and a shroud grave clothes. This area has different characters on wearing customs. It is changed into the kind of Dopo, with its back not cutting. The hemp sack is almost used as its subject matter. It doesn't have collar strip for the classification of one's family in any case, and Dopo which is prepared for necessary articles for marriage can not be taken tack after seperating by divorce.

• The Journal of the Acoustical Society of Korea
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• v.33 no.1
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• pp.40-47
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• 2014

Interaction between the unsteady flow emitted from the blade of the centrifugal fan and the volute tongue region of fan duct is known as the main noise source of the centrifugal fan. In this paper, the relative contributions of the volute tongue region of the centrifugal fan is analyzed to utilize as the foundation data of low noise design. The internal hybrid CAA (Computational Aero-Acoustics) method is used to predict noise radiated from the main noise source. This method is the noise prediction technique using CFD (Computational Fluid Dynamics), Acoustic analogy, and BEM(Boundary Element Method). The relative contributions of the centrifugal fan volute tongue region using the hybrid CAA method show that the region between the cut-off and the scroll has high contribution than the region between the cut-off and the outlet and the hub region of blade has high contribution than the shroud region of blade. These results is utilized as the important data for the development of low noise centrifugal fan.

• International Journal of Fluid Machinery and Systems
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• v.8 no.3
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• pp.193-201
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• 2015

This paper deals with the influence of leakage flow existing in SHF pump model on the analysis of internal flow behaviour inside the vane diffuser of the pump model performance using both experiments and calculations. PIV measurements have been performed at different hub to shroud planes inside one diffuser channel passage for a given speed of rotation and various flow rates. For each operating condition, the PIV measurements have been trigged with different angular impeller positions. The performances and the static pressure rise of the diffuser were also measured using a three-hole probe. The numerical simulations were carried out with Star CCM+ 9.06 code (RANS frozen and unsteady calculations). Some results were already presented at the XXth IAHR Symposium for three flowrates for RANS frozen and URANS calculations. In the present paper, comparisons between URANS calculations with and without leakages and experimental results are presented and discussed for these flow rates. The performances of the diffuser obtained by numerical calculations are compared to those obtained by the three-holes probe measurements. The comparisons show the influence of fluid leakages on global performances and a real improvement concerning the efficiency of the diffuser, the pump and the velocity distributions. These results show that leakage is an important parameter that has to be taken into account in order to make improved comparisons between numerical approaches and experiments in such a specific model set up.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.4
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• pp.387-394
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• 2020

A parametric study of a 2.5 kW class propeller type micro hydraulic turbine was performed. In order to analyze the internal flow characteristics in the hydraulic turbine, three dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model were used and the hexahedral grid system was used to construct computational domain. To secure the reliability of the numerical analysis, the grid dependency test was performed using the grid convergence index method based on the Richardson extrapolation, and the grid dependency was removed when about 1.7 million nodes were used. For the parametric study, the axial distance at shroud span (L) between the inlet guide vane and the runner, and the inlet and outlet blade angles (β₁, β₂) of the runner were selected as the geometric parameters. The inlet and outlet angles of the runner were defined in the 3 spans from the hub to tip, and a total of 7 geometric parameters were investigated. It was confirmed that the outlet angles of the runner had the most sensitive effect on the power and efficiency of the micro hydraulic turbine.

• Journal of the Korean Society of Costume
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• v.66 no.5
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• pp.149-162
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• 2016

This study examines the costume artifacts discovered in the burial site of Choi Kyung Sun(1561~1622), which was moved from Gangwon in Gangrung Province. About 30 artifacts, including costumes, were recovered from Choi Kyung Sun's grave. The collection of men's coats discovered in the grave consisted of a Dallyeong (Official's robe), Jing-nyeong(Man's coat), Jungchi-mak(Man's coat), Cheolrik(Man's coat), Chang-ui(Man's coat), Gwang-su-ju-ui(Man's coat), and Do-po(Man's coat). Han-sam(Undershirts), Jeo-go-ri(Jacket), and trousers were also recovered, along with several items made of textiles, such as the cloth used to shroud and wrap the body. The costume artifacts recovered from Choi Kyung Sun's grave have several characteristics that distinguish them from other early 17th-century costume artifacts. Firstly, the body had a hairband made from horsehair. Secondly, the men's trousers were of the type worn before the Japanese Invasion(1592~1597). Thirdly, the style of the coats' sleeves, when compared with artifacts from other regions, was from an earlier era. Through these costume artifacts, it can be inferred that people who lived in the Gangwon Province, which was far away from Seoul, continuously wore outfits from before the Japanese Invasion, and trends spread slowly.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.937-942
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• 2008

This paper presents a case history on failures of impeller and shaft due to pressure pulsation at single stage feed water pumps in 700 MW nuclear power plant during commissioning operation. The pumps had been service and had run for approximately $40{\sim}50$ hours. For the most part, the failures of impeller occurred with the presence of a number of fatigue cracks. All cracks were associated with the deleterious surface layer of impeller by visual and metallurgical examination. On-site testing and analytical approach was performed on the systems to diagnose the problem and develop a solution to reduce the effect of exciting sources. A major concern at high-energy centrifugal pump is the pressure pulsation created from trailing edge of the Impeller blade, flow separation and recirculation at centrifugal pumps of partial load. Pressure pulsation due to the interaction generating between impeller and casing coincided with natural frequencies of the impeller and shaft system during 1ow load operation. It was identified that dynamic stress exceeding the fatigue strength of the material at the thin shroud section due to the hydraulic instability at running condition below BEP.

• Nuclear Engineering and Technology
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• v.24 no.2
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• pp.111-120
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• 1992

This paper investigates the dynamic characteristics of spacer grid impact loads and the effects of variations in the amplitude and frequency of the core plate motions on the resultant impact loads. A model of the longest row (15 fuel assemblies) across the core is analyzed using the input motions generated from safe shutdown earthquake. Input excitations consist of time history motions applied to the core support plate, fuel alignment plate and core shroud. The responses are determined for a set of four parameter runs with respect to the amplitude and frequency changes. Spacer grid impact loads and normalized input values for all cases are presented. The results show that changing the natural frequency has negligible effect but changing the amplitude of the input motions has a significant effect on the grid impact loads Therefore, time history analysis is not necessary for a shifted case to get the core responses under the seismic excitation.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.1
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• pp.71-79
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• 1995

Journal of the Korean Society of Clothing and Textiles Vol. 19, No. 1 (199i) p. 71~79 The authors study on the traditional textile production and the formal dress through the field research concerning the folk attitude toward dress style around the Mt. Kumo area. In this area, people produced and wove hemp, cotton, and silk except ramie. Because of poor production of raw materials, they produced textiles only for self-sufficiency. Every household dealt with dyeing on a small scale. In the past, people dyed cloth natually using plants as material. Natural dyeing, however, gradually changed into chemical one since the Japanese rule. The formal dresses, which people wore on particular occasions such as the hundredth day after child's brith, the first birthday, and traditional holidays, were very meager due to poor living standards. People could not see the formal dresses with full decoration. Bride and bridegroom were the village.owned wedding dresses, and if they could not afford to, they simply put cloth on to remember the occasion. People around the Mt. Kumo area, however, provided fully-decorated shroud and ritual robes to the level of other better-off areas. It seemed to be the result of influence of deep-rooted Confucianism in Gyungbuk province. This Phenomenon could be found in the folk dress style in other regions as well as the Mt. Kumo area in Gyungbuk province.

• Advances in aircraft and spacecraft science
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• v.7 no.4
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• pp.371-385
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• 2020

A forward-facing aerospike attached to a payload fairing of a satellite launch vehicle significantly alters its flowfield and decreases the aerodynamic drag in transonic and low supersonic speeds. The present payload fairing is an axisymmetric configuration and consists of a blunt-nosed body along with a conical section, payload shroud, boat tail and followed by a booster. The main purpose of the present numerical simulations is to evaluate flowfield and assess the performance of aerodynamic drag coefficient with and without aerospike attached to a payload fairing of a typical satellite launch vehicle in freestream Mach number range 0.8 ≤ M_∞ ≤ 3.0 and freestream Reynolds number range 33.35 × 10⁶/m ≤ Re_∞ ≤ 46.75 × 10⁶/m whichincludes the maximum aerodynamic drag and maximum dynamic conditions during ascent flight trajectory of the satellite launch vehicle. A numerical simulation has been carried out to solve time-dependent compressible turbulent axisymmetric Reynolds-averaged Navier-Stokes equations. The closure of the system of equations is achieved using the Baldwin-Lomax turbulence model. The aerodynamic drag reduction mechanism is analysed employing numerical results such as velocity vector plots, density and Mach contours in conjunction with the experimental flow visualization pictures. The variations of wall pressure coefficient over the payload fairing with and without aerospike are exhibiting different kind of flowfield characteristics in the transonic and low supersonic speeds. The numerically computed results are compared with schlieren pictures, oil flow patterns and measured wall pressure distributions and exhibit good agreement between them.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.72-78
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• 2003

In the present paper, computational studies on the hydrodynamic behavior of the inducer for the rocket-engine turbopump are presented including the effect of the mass flow rate. As the mass flow rate is increased, the inducer showed better performance with weak back flows which may have deleterious effects upon the anti-cavitation ability. But the adopted inducer showed low head rise with high volume flow rates, which may be caused by the small passage area near the trailing edge. The static pressure distributions at the shroud surface are compared with experimental results showing very good agreements except near the leading edge where strong back flows are present. The overall performance of the inducer such as, efficiency, head rise is also compared with experiments. The computational results are generally in good agreements with experimental ones near the design point, but two results show discrepancy at the high flow rate.