• 한국터널지하공간학회 논문집
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• 제13권2호
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• pp.83-96
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• 2011

현재 국내터널에 주로 사용되는 공법은 NATM(New Austrian Tunneling Method)으로 원지반의 강도를 유지하고 보강하는 수단으로 록볼트, 숏크리트, 지보재를 이용하여 암반굴착 직후 원지반의 지지능력을 최대로 활용하여 지반을 안정화시킴으로 터널의 안전성을 유지시키는 공법이다. 과거에는 철망(wire mesh)보강 숏크리트가 주로 사용되었으나 시공기술의 발전을 통한 공기향상을 목적으로 현재는 강섬유보강 숏크리트(steel fiber reinfored shotcrete)가 국내 대다수 터널현장에 사용되고 있다. 그러나 터널 현장의 강섬유보강 숏크리트가 시공된 벽면의 강섬유 혼입량을 조사한 결과, 대부분 예상보다 부족한 것으로 측정되어 이에 대한 시방기준의 수립과 강섬유 부족구간의 보강대책의 필요성이 제기되고 있다. 따라서 본 연구에서는 강섬유 혼입량 부족 대한 터널의 안정성 확보 및 문제점을 보완하기 위해 새로운 형태에 강섬유보강재를 개발하려고 한다.

• 한국전자통신학회논문지
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• 제10권1호
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• pp.133-138
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• 2015

편광유지 광결정 광섬유를 이용하여 무게센서를 제작하여 실험을 하였다. 본 논문의 센서시스템은 3 dB 커플러, 반파장판, 광원으로 구성되어진다. 무게가 편광유지 광결정 광섬유에 가해지면 파장이동을 측정한다. 센서감지부로 원형형태와 직선형태의 2 종류로 제작하여 특성을 조사하였다. 직선형태로 이루어진 센서의 감도는 680 pm/kg 였으며, 원형형태로 구성된 센서의 감도는 270 pm/kg 이었다. 두 가지 형태로 제작된 센서는 선형성이 좋았으며, 감도는 직선형태로 이루어진 센서가 좋음을 알 수 있었다.

• Radiation Oncology Journal
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• 제7권2호
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• pp.299-303
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• 1989

Authors have developed highly reproducible calibration method for the Micro-Selectron HDR Ir-192 system (Nucletron, Motherland). The new jig has a 10cm radius circular hole in the $30cm{\times}30cm{\times}0.2cm$ acrylic plate, and 5F flexible bronchial tubes are attached around the hole. The source moves along the circle in the tubes and the ionization chamber is placed verticaly at the center of the circular hole (center of the jig). Dose distribution near the center was derived theoretically, and measured with the film dosimetry system. Theoretical calculation and measurement show the error margin below $0.1\%$ for 1mm or 2mm position deviation. We have measured at 12 and 24 points of circle with 1, 6, 11 and 21 second dwell time of source in order to calculate the activity of the source. Measurements have been repeated daily for 50 days. The accuracy and the reproducibility are below $1\%$ error margin. The half life of the source from our measurement is estimated $73.4\pm0.4$ days.

• 수산해양기술연구
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• 제46권1호
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• pp.56-69
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• 2010

This study was intended to determine the maneuverability of the vessel CHARMBADA. When the rudder angle was at $10^{\circ}$, $20^{\circ}$ and $30^{\circ}$, the maximum advance by slow, half and full ahead were varied in the range of 523.6-131.3m, 528.8-177.2m and 530.6-219.7m, respectively. The maximum transfer was 799.9-181.3m, 792.1-232.8m and 807.7-316.9m, respectively. The turning circle ability was better during starboard turning. When the rudder angle was $10^{\circ}$, $20^{\circ}$ and $30^{\circ}$, variation in the maximum advances was 392.0m, 245.0m and 153.0m. The maximum transfer was 528.0m, 339.0m and 218.0m, respectively based on the regression equations. As the rudder angle became bigger, the maximum advance or maximum transfer became smaller by the exponential function. The advance inertia took 127sec, 145sec, 181sec each until the vessel speed was 7.0konts, 12.0konts, 17.0konts. The static inertia took 245sec, 269sec, 300sec each until the vessel speed was under 2.0konts and the advance distance was 114.4m, 181.2m, 197.0m each. Accordingly, the static inertia was inclined to increase to scale according to the increase in vessel speed. For the CHARMBADA, the smaller the rudder angle was, the much bigger the turning circle became due to adhesion to the skeg, thereby lowering the vessel's turning ability.

• 한국가구학회지
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• 제20권1호
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• pp.61-70
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• 2009

This study intended to explore English of furniture tenn in relation to the joints and moldings in traditional Korean wood furniture, a base of Korean wood furniture, for the development of Korea furniture in the future. The joints such as butt joint, rabbeted joint, mitered joint, mortise-and-tenon joint, fist joint, and finger joint, and the moldings such as a piece of thread molding, half-circle molding, cove molding, flat molding, and triangle molding were analyzed between English and Korean language. The results were only basic terms which must be researched and unified in the traditional Korean furniture. Therefore, the terms in relation to the types, the details, the hardware, and so on, will have to be studied in terms of the meaning originated from the traditional craftsmen.

• The Korean Journal of Ceramics
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• 제5권4호
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• pp.368-370
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• 1999

Using DC faced target sputtering method we grow AIN the films on the $Al_2O_3$(0001) substrate with varying thickness(17$\AA$-1000$\AA$). We measured x-ray diffraction(XRD) profiles by synchrotron radiation($\lambda$=1.12839 $\AA$) with four circle diffractometer. The full width half maximum(FWHM) of rocking curve for the AIN (0002) diffraction of the film grown at $500^{\circ}C$ was $0.029^{\circ}$. Also, we confirmed that the stress between AIN thin film and $Al_2O_3$(0001) substrate was reduced as increasing AIN film thickness, and the critical thickness of 400~500 $\AA$, defined as a lattice constant in the film agrees with that in a bulk without stress, was obtained.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.761-765
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• 1996

This paper describes the forging of circular tooth profiled gears as a series of development of simulator for non-axisymmetric parts that being used at the pump pulley, timing belt pulley etc. in automobiles. The half pitch of gear is divided into 6 deformation regious and kinematically admissible velocity fields for those regions are proposed. The neutral surface is introduced torepresent inner flow of material during forging operation with flat punch and, for each step, it is assumed as a circle. The upper bound solutions obtained from the suggested kinematically admissible velocity fields are in good agreement with experimental results and they are useful to predict the capacity of forging press for forging of circular gears.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 추계학술대회논문집
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• pp.37-47
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• 1995

Forging of trapezoidal spline, serration and square spline with solid cylindrical billets and hollow one has been investigated by means of upper bound method. Kinematically admissible velocity fields for forging of splines have been proposed in this study. The half pitch of splines has been divided into deformation regons. The neutral surface is introduced into forging of splines with flat punch and, for each step, it is assumed as a circle with its radius rn upper bound solutions obtained obtained by proposed kinematically admissible velocity fields are useful to predict the loads for forging of splines.

• 한국정밀공학회지
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• 제22권7호
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• pp.79-87
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• 2005

This paper summarizes the work on the development of a simulation program for modelling the process of machining quasi-three dimensional shape with the excimer laser beam on a constantly moving polymers. Relatively simple masks of rectangle, triangle and half circle shape are considered. The etching depth is calculated by considering the number of laser pulses irradiated on the specimen surface. It was found that similar shapes as experimental results can be obtained by choosing suitable parameters of moving velocity, moving distance and mask sizes.

• 한국정밀공학회지
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• 제13권1호
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• pp.108-115
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• 1996

Forging of trapezoidal spline, serration and square spline with solid cylindrical billets and hollow one has been investigated by means of upper bound method. Kinematically admissible velocity fields for forging of splines have been proposed in this study. The half pitch of spline has been divided into several deformation regions. The neutral surface is introduced into forging of splines with flat punch and, for each step, it is assumed as a circle with its radius $r_n$. Upper bound solutions obtained by proposed kinematically admissible velocity fields are useful to predict the loads for forging of splines.