• 콘크리트학회논문집
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• 제14권1호
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• pp.8-15
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• 2002

This paper presents a study carried out for the seismic capacity in reinforced concrete(RC) piers by the confinement effect of transverse reinforcement as such a hooked-tied, welded-tied and spiral reinforcement. In order to assess the seismic capacity with transverse reinforcement, experiment리 and analytical methods were adopted. A RC column survey was conducted based on eight one-fourth scale single circular column specimens designed and tested under slow horizontal cyclic loads. Two cases were analyzed. The confinement effect of concrete by transverse reinforcement is considered not in Case 1 but in Case 2. Also, we studied the propriety of making use of the method in which a carbon fiber rod replace spiral reinforcement in RC piers. In experimental tests, a welded-tied and spiral reinforcement has a good seismic capacity, but a carbon fiber rod presents low ductility in comparison with a hooked-tied reinforcement. In an analytical study, displacement ductility is approximate to the experimental result because of considering the confinement effect of the transverse reinforcement. Even if the confinement effect of the transverse reinforcement is considered, the analytical results for ductility of the specimens with welded-tied and spiral reinforcement show an excessive underestimation of the experimental results.

• 한국항해항만학회지
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• 제32권6호
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• pp.453-458
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• 2008

원형실린더에 크기가 다른 제어봉을 부착하여 2차원 단면 유통특성에 대해서 시간평균유동장을 계측하여 근접후류 제어에 관하여 PIV기법을 적용하여 연구를 수행하였다. 모델시험은 각각 크기가 다른 제어봉을 적용하였으며($d/D=0.1{\sim}d/D=0.5$) 레이놀즈수는 원형실린더의 직경을 기준으로 Re=15,000으로 적용하였다. 유동장의 속도분포론 획득하기 위해 2프레임 상호상관법을 이용하였다. 실험에 적용된 원형실린더(D=50mm)에 제어봉을 부착한 결과를 상호 비교함으로서 시간평균속도분포와 제어봉에 의한 유동제어 효과를 알 수 있었다.

• Journal of electromagnetic engineering and science
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• 제7권3호
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• pp.129-133
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• 2007

In this paper, we present the development of an antenna specialized for the maritime collision avoidance system. This antenna is configured as the dielectric rod partially embedded in the metal cavity to reduce the overall size, simultaneously assuring the mechanical sturdiness against the challenging oceanic weather conditions. More importantly, the design has been carefully done to meet the requirements on the radiation pattern(with the slope < 5 dB/deg in the elevation(E-plane), circular in the azimuth) suitable to receiving the reflected signals from the other objects on the sea. To find the optimal design parameters, the genetic algorithm has been used to meet the goals of the desired return loss and pattern. This design methodology is validated by the good agreement between the calculation and measurement.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.153-159
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• 2002

This paper deals with the measurement of the fluid viscosity by using the torsional vibration of a circular red excited by a torsional vibrator at one end. The effect of an adjacent viscous fluid on the torsional vibration of the rod has been studied theoretically and expressed in terms of the mechanical impedance. The theoretically-obtained trend that the mechanical impedance is proportional to the square root of the viscosity times the density of the fluid has been confirmed by the impedance measurement. The paper demonstrates that a torsionally-vibrating rod can be used as a sensor to measure the viscosity of a fluid.

• 소음진동
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• 제8권5호
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• pp.908-913
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• 1998

Analogous problem for a gear dynamics where helical gears excite logitudinal forces in the shaft is studied. These shaft forces excite the supporting gear housing through bearing, causing structural vibration. In this study, shaft is modeled as a rod, and bearing is modeled by a massless spring. A simple model for gear housing is a clamped circular plate. To model this force transmission, the transfer functions from the shaft to a clamped circular plate are analytically derived by using the spectral method and four-pole parameter. Finally, radiated noise is computed, using the acoustic relations due to plate surface vibration.

• Journal of Welding and Joining
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• 제25권3호
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• pp.85-91
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• 2007

The conventional study on the laser surface transformation hardening has been carried out with a beam of the specified shape and uniform power-intensity distribution in order to ensure the uniformity of the hardening depth. Two types of beams - the circular gaussian beam and rectangular beam of the uniform power-intensity distribution were used in this study. we were supposed to optimize the process parameters and to compare the hardening results with two optics respectively. As a result, the hardness distribution of the hardened zone was similar in both cases and the hardened phase by the rectangular beam was denser than that by the circular gaussian beam.

• 전기학회논문지
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• 제65권9호
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• pp.1564-1570
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• 2016

This study proposes a newly modified form of existing ground electrodes in order to secure trust of grounding system for large current caused by a stroke of lightning. Proposed planar earth structure has a several needle electrodes around a circular rod and 4 plane electrodes in all directions. The plane electrodes are fused with the insulator on the linear rod, so that they're electrically isolated. The concept is to increase the discharge amount of earth structure using multiple discharge paths like needle and plane electrodes. To check the discharge efficiency of the suggested scheme, the discharge currents are compared with typically used two kinds of ground rods. To ensure accuracy in the measurement of the discharge current, the same material was used for the comparison model. Also, the ground resistance are simulated by CDEGS commercial software and the results are compared with measured data. Based on this kind of experimental study, the suggested ground rod can be used when designing a ground system or when constructing a ground system at the site.

• 대한기계학회논문집
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• 제19권5호
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• pp.1269-1279
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• 1995

An experimental study is carried out on turbulent diffusion flames stabilized by a circular cylinder in a divergent duct flow. A commercial grade gaseous propane is injected from two slits on the rod as fuel. Flame stability limits, as well as size and temperrature of recirculation zone, are measured by direct and schlieren photographs to clarify the characteristics and structure of diffusion flames and to assess the effect of various divergent angle of duct. The results of the present study are as follows. Temperature in the recirculation zone decreases with increasing divergent angle. The blow-off velocity in parallel duct is higher than that in divergent duct. Critical blow-off velocity is expected to be about 8-12 degree through blow-off velocity pattern. Regardless of divergent angles, the length of recirculation zone is nearly constant, and this length becomes longer with rod diameter. Pressure gradient has an effect on the eddy structure in shear layer behind the rod. With the increase of divergent angle, large scale eddies by dissipated energy in shear layer are split into small scale eddies, and the flame becomes a typical distributedreacting flame.

• 복식문화연구
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• 제9권5호
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• pp.712-722
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• 2001

The purpose of this study is to classify of the Hair ornaments in old tombs of the Three Kingdom States. Hair ornaments was divided into Combs, Rod-like hairpins, Chae[;釵], Boyo[;步搖] Combs were 2 type in according to the tooth's space, wide-tooth comb[;梳] and fine-tooth comb(;比). The general name of two type was called Jeul(;櫛). Combs were excavated from the only ancient Silla tombs. Rod-like hairpins were called Gha(叉) or Jam(:簪). They were found in most of the old tombs in Goauryeo, Baekje, ancient Silla tombs. The style was L-type and embellished circular head-type. Chae(;釵) was understand Cha(:叉) that had two tongs. Chae(:釵) was generally U-type and rarely hairtweezers -type. Jakchae(;爵釵) was understand distinctive Chae(;釵) hanged with phoenix. This type was excavated from the only Baekje tombs of King of Muryeong. Boyo(;步搖) was originally a hair decoration of the northern nomadic tribes which had been introduced to the Wijin period. Boyo gained its popularity by the women in Dang Dynasty, hair ornaments were considered indicators of status and wealth. Boyo(;步搖) hair accessory features of which are suspended from a elaborate hairpin structure. Such pieces were designed to sway as their wearer walked. The bequest was not found, but we catch the Boyo(; 步搖) that was women'head decoration in painting of old tombs in Goguryeo.

• 대한기계학회논문집
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• 제19권11호
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• pp.2981-2994
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• 1995

In order to elucidate the effects of positive pressure gradient on flame properties, structure and stabilization, an experimental study is made on turbulent diffusion flame stabilized by a circular cylinder in a divergent duct flow. A commercial grade gaseous propane is injected from two slits on the rod as fuel. In this paper, stabilization, characteristics and flame structure are examined by varying the divergent angle of duct. Temperature, ion current and Schlieren photographs were measured. It is found that critical divergent angle is expected to be about 8 ~ 12 degree through blow-off velocity pattern to divergent angle and the positive pressure gradient influences the flame temperature, intensity of ion current and eddy structure behind the rod. With the increase of divergent angle, typical temperature of recirculation zone is low but intensity of ion current is high in shear layer behind rod. Energy distributions of fluctuating temperature and ion current signals turn up low frequency corresponding to large scale eddies but high frequency corresponding to small scale eddies as well as low with the increase of divergent angle. Therefore the flame structure becomes a typical distributed-reacting flame.