• Imaging Science in Dentistry
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• 제36권1호
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• pp.55-62
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• 2006

Purpose : To find the cause of root curvature by use of panoramic and lateral cephalometric radiograph. Materials and Methods : Twenty six 1st graders whose mandibular 1st molars .just emerged into the mouth were selected. Panoramic and lateral cephalometric radiograph were taken at grade 1 and 6, longitudinally. In cephalometric radio graph, mandibular plane angle, ramus-occlusal plane angle, gonial angle, and gonion-gnathion distance (Go-Gn distance) were measured. In panoramic radio graph, elongated root length and root angle were measured by means of digital subtraction radiography. Occlusal plane-tooth axis angle was measured, too. Pearson correlations were used to evaluate the relationships between root curvature and elongated length and longitudinal variations of all variables. Multiple regression equation using related variables was computed. Results : The Pearson correlation coefficient between curved angle and longitudinal variations of occlusal plane-tooth axis angle and ramus-occlusal plane angle was 0.350 and 0.401, respectively (p<0.05). There was no significant correlation between elongated root length and longitudinal variations of all variables. The resulting regression equation was $Y=10.209+0.208X_1+0.745X_2$ (Y: root angle, $X_1$: variation of occlusal plane-tooth axis angle, $X_2$: variation of ramus-occlusal plane angle). Conclusion : It was suspected that the reasons of root curvature were change of tooth axis caused by contact with 2nd deciduous tooth and amount of mesial and superior movement related to change of occlusal plane.

• 대한치과교정학회지
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• 제25권3호
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• pp.287-297
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• 1995

경북대학교 치과 대학에서 두개안면골 성장에 관한 누년적 연구의 일환으로 남자 25명, 여자 21명을 대상으로 평균 연령 8.5세에서 16.5세까지 격년 간격으로 촬영한 두부X선 규격사진을 이용하여 Ricketts분석법의 항목중 V.T.O.작성의 초기 단계인 치료전의 성장 예견시에 필요한 각도 및 거리 계측 항목을 선정 계측하여 다음과 같은 결론을 얻었다. 1. 계측항목중 연령에 따른 변화를 보이지 않는 항목은 성장 방향을 나타내는 facial axis angle, FH to palatal plane angle, BA-NA-A angle, lower facial height 및 lower incisor protrusion이었다. 2. 연령에 따라 지속적으로 증가하는 항목(anterior and posterior cranial base length, facial axis length, condyle axis length, corpus axis length)에서 연간 성장 변화량, 평균 연성장량 및 8년간 변화량을 구하였다. 3. 연령에 따라 지속적으로 증가하는 모든 계측 항목에서 12세 이후의 대부분의 연간 성장변화량, 평균 연성장량 및 8년간 변화량에서 남녀간 유의차를 나타내었다(P<0.05). 4. 남녀별로 각 연령에서 각 계측치의 평균치를 이용하여 visual norm을 작성하였다. 남자의 경우 각 기간동안 상당한 성장을 보였으며 특히 12-14세 기간에 가장 많은 성장을 나타내었고, 여자의 성장 변화에서는 10-12세 사이에서 가장 많은 성장을 나타내었으며 이후 점차 감소를 보였다.

• 한국자기학회지
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• 제7권3호
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• pp.134-139
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• 1997

비정질 $Co_{66}$Fe$_{4}$NiB$_{14}$Si$_{15}$에서 리본의 종방향에 대하여 여러 가지 각도를 갖는 시편을 식각법으로 제작하여 100 kHz의 교류전류에서 4 단자법으로 MI 신호를 측정하였다. H=0 근처에서 30 .deg. 시편부터 dip이 나타났으며, 그 크기는 각도에 따라 단조증가하였다. 자기장 크기에 따라 Mi 신호는 증가하였고, 일정한 자기장에서 식각각도에 따라 MI 신호는 증가하다가 90 .deg. 시편에서 감소하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.176-180
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• 2002

All types of VLM-s process include the linear heat cutting of EPS foam to generate a layer with 3D shape. The dimensional accuracy and part quality of the cut part are dependent on the thermal characteristics in the EPS foam. The thermal characteristics are determined by operating parameters such as an effective heat input and cutting angle. The objective of this study is to investigate into the influence of cutting angle on the kerfwidth and the melted length of the cut part using the numerical analysis and the experiments in generally sloped cutting with two cutting angles. In order to estimate an accurate temperature field, the transient thermal analysis using moving coordinate system, the fully conformed mesh and the heat flux model with two cutting angles is carried out. From the results of the analysis and the experiments, it has been found that the influence of the rotational angle about x-axis in which the rotational axis is normal with hotwire cutting direction is appreciably negligible in comparison with that of the rotational angle about y-axis.

• International Journal of Aeronautical and Space Sciences
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• 제8권2호
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• pp.11-16
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• 2007

This paper describes the cycloidal wind turbine, which is a straight blade vertical axis wind turbine using the cycloidal blade system. Cycloidal blade system consists of several blades rotating about an axis in parallel direction. Each blade changes its pitch angle periodically. Cycloidal wind turbine is different from the previous turbines. The wind turbine operates with optimum rotating forces through active control of the blade to change pitch angle and phase angle according to the changes of wind direction and wind speed. Various numerical experiments were conducted to develop a small vertical axis wind turbine of 1 kW class. For this numerical analysis, the rotor system equips four blades consisting of a symmetric airfoil NACA0018 of 1.0m in span, 0.22m in chord and 1.0m in radius. A general purpose commercial CFD program, STAR-CD, was used for numerical analysis. PCL of MSC/PATRAN was used for efficient parametric auto mesh generation. Variables of wind speed, pitch angle, phase angle and rotating speed were set in the numerical experiments. The generated power was obtained according to the various combinations of these variables. Optimal pitch angle and phase angle of cycloidal blade system were obtained according to the change of the wind direction and the wind speed. Based on data obtained from the above analysis, control device was designed. The wind direction and the wind speed were sensed by a wind indicator and an anemometer. Each blades were actuated to optimal performance values by servo motors.

• 대한족부족관절학회지
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• 제18권3호
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• pp.119-123
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• 2014

Purpose: This study was designed to evaluate the clinical efficacy of temporary K-wire fixation in F-plate fixation for displaced intra-articular calcaneal fractures. Materials and Methods: Two groups (group 1 with F-plate fixation only and group 2 with temporary K-wire fixation and F-plate fixation) of patients were included in this study. The temporary K-wire was removed six weeks after the operation. Each group consisted of 33 cases. Rotational axis angles were measured radiographically and the foot and ankle outcome score (FAOS) was used for clinical assessment. Results: In group 1, the mean rotational axis angle was reduced from $27^{\circ}$ preoperatively to $5.59^{\circ}$ postoperatively and the angle at last follow-up was $9.94^{\circ}$. There was an increase in angle of $4.35^{\circ}$ between postoperative and the last follow-up measurement. In group 2, the mean rotational axis angle was reduced from $21.2^{\circ}$ preoperatively to $4.39^{\circ}$ postoperatively and the angle at last follow-up was $5.91^{\circ}$. There was an increase in angle of $1.52^{\circ}$ between postoperative and the last follow-up measurement. Significant difference in the changes of rotational axis angle was observed between the two groups. However, no significant difference in FAOS was observed between the two groups. Conclusion: Temporary K-wire fixation can prevent reduction loss when treating displaced intra-articular calcaneal fractures with an F-plate.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.293-296
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• 2007

Gamma curve is one of the most important optical performance characteristics of a liquid crystal display. we present investigations on the relationship between gamma and polarizer. The gamma curve is affected by the angle of the polarizer absorption axis. When the crossed angle between the two polarizers turns larger, gamma values will decrease. The gamma variation caused from each polarizer variation could be improved by monitoring and controlling the axial direction of the polarizers.

• 한국운동역학회지
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• 제13권2호
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• pp.75-87
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• 2003

The purpose of this study was to identify the mechanical factors that are crucial to the successful double salto backward piked dismount on the parallel bars. The subjects were 5 national gymnasts(G1: sucessed landing, G2: failed landing), two video cameras were used to record the dismount of the subjects. It summarizes that (a) It is important to make small slope angle(X axis, Y axis) at release, whereas it makes large shoulder angle and trunk rotation angle. (b) It is important to prepare landing in advance, reducing vertical velocity and making large hip angle at BTO(body take off). (c) It is also important to make small knee angle and hip angle, and reduce the angle of trunk rotation.

• 반도체디스플레이기술학회지
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• 제18권2호
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• pp.87-91
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• 2019

In this paper, we have development of horizontal attitude monitoring system for agricultural robots. A two-axis gyro sensor and a two-axis accelerometer sensor are used to measure the horizontal attitude angle. The roll angle and pitch angle were measured through the fusion of the gyro sensor signal and the acceleration sensor signal for the horizontal attitude monitoring of the robot. This attitude monitoring system includes GPS and Bluetooth communication module for remote monitoring. The roll angle and pitch angle can be measured by the error of less than 1 degree and the linearity and the reproducibility of the output signal are excellent.

• 한국공작기계학회논문집
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• 제11권6호
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• pp.1-9
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• 2002

This study describes the geometric characteristics and the 5-axis machining method in order to make end mill cutter coming with insert tips. End mill geometry is consisted of flute part and insert tip part. Flute part modeled by using ruled surfaces with constant helix angle, and insert tip part modeled by rectangular planes containing tapped hole of specified direction in its center. In this study, the modeled insert tip part considered both of a radial rake angle and a axial rake angle, because they were important cutting conditions. In order to machining the virtual end mill defined from geometric characteristics, we programmed a special software to machining the end mill considered in this study. This software can generate NC-codes about following processes, end milling or ball end milling of flute part end milling of rectangular plane, centering of hole, drilling of hole, and tapping of hole. Ant sampled end mills were modeled and machined on 5-axis CNC machining center with two index tables. Since machined end mills were very agreeable to designed end mills, we saw that the method proposed in this study can be very useful for manufacturing of end mill body with insert tip.