• Journal of Astronomy and Space Sciences
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• 제31권4호
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• pp.347-351
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• 2014

Planetary exploration rovers are likely to make a trip on a winding and sloping road of irregular surfaces to the destination in order to accomplish scientific missions. One of the key technologies for rovers is a suspension for traveling and performing exploration missions; the suspension is an essential area of technology for a stable movement of a rover. In this study, an 8-wheel suspension is designed to enable efficient climbing of slopes on a passage to the destination. For the two front wheels among the eight wheels, the moment at the pivot connecting two wheels is derived when the distance between the wheels and the torque of wheels are same. A test experiment was performed to compare the magnitude of moment according to the change in tilt angle and the position of the pivot. Finally, a suspension design considering the position of the pivot was proposed to enhance the hill-climbing performance.

• 한국융합학회논문지
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• 제11권4호
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• pp.343-350
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• 2020

본 연구는 여자 핸드볼 국가대표 선수를 대상으로 관성센서(IMU)를 활용하여 5개월 동안 국내 또는 국외 연습경기 총 16경기를 대상으로 움직임을 정량화하고 훈련의 효율성과 포지션별 움직임 차이를 확인하고자 하였다. 골키퍼를 제외한 15명의 필드플레이어를 대상으로 하였으며 연구결과 다음과 같은 결론을 얻었다. 플레이어로드는 Wing > Back > Pivot 순으로 나타났고 국외경기에서 높은 것으로 나타났다. 좌·우 방향전환은 Pivot이 저강도에서 가장 많은 것으로 나타났고 중·고강도는 Back에서 가장 많이 나타났다. 국외경기의 저·중강도 방향전환 움직임이 많은 것으로 나타났다. 저강도 가속과 감속은 Pivot이 가장 많은 것으로 나타났고 중·고강도 가속과 감속은 Back이 가장 많은 것으로 나타났다. 국외경기에서 저·중강도 가속과 저·중·고강도 감속이 많은 것으로 나타났다. 점프는 Back이 중강도, Wing이 고강도 점프가 많이 나타났지만 경기 유형간 차이는 나타나지 않았다.

• Korean Journal of Acupuncture
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• 제39권2호
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• pp.23-33
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• 2022

Objectives : The purpose of this study is to establish a Korean medical perspective on the human body through understanding of the meridians according to the distribution of the three yin and three yang (삼음삼양) and the opening, closing and pivot (관합추) as defined in ≪Huangdi's Internal Classic≫. Methods : A total of 8 medical databases including KISS, Earticle, DBpia, RISS, OASIS, KMbase, and ScienceON were used to search studies published through July 2021, and literature was included without limitations on the publication period. The search terms were "(meridian OR acupoint OR meridian sinew) AND position" OR "Gwan-Hap-Chu" OR "Gae-Hap-Chu" OR "three yin and three yang". Two researchers independently made choices among the searched literature based on the preplanned selection/exclusion criteria. The search terms were"(meridian OR acupoint OR meridian sinew) AND position" OR "Gwan-Hap-Chu" OR "Gae-Hap-Chu" OR "three yin and three yang". Results : Of the 36 obtained from the survey, 19 (53%) followed the definitions of "internal diameter" for "three yin and three yang" and "the opening, closing and pivot," but 6 (about 16%) took a neutral position and 10 (22%) avoided mentioning. Therefore, it was judged that research was needed to end the debate on the distribution of 'three yin and three yang' and 'the opening, closing and pivot'. In order to apply the definition of ≪Huangdi's Internal Classic≫ on 'distribution of the three-yin and three-yang' and 'the opening, closing and pivot' to the upper limb and lower limb as well as the torso of the human body, this author proposed a human body model with both upper limb and lower limb attached, inspired by the posture of the fetus in the developmental stage. Conclusions : In this study, using a new human body model, it was revealed that the distribution of the three yin and three yang and the opening, closing and pivot' as defined in the ≪Huangdi's Internal Classic≫ can be applied not only to the torso of the human body, but also to the upper limb and lower limb. Based on the understanding of meridians, the selection of meridians in the clinical acupuncture should be made accurately, and continuous interest and research on this are expected.

• 한국기계가공학회지
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• 제14권6호
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• pp.49-56
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• 2015

For designing working devices of construction equipment, it is necessary to consider not only sufficient working ability but also available working range. Therefore, it is important to select the appropriate pivot positions of links. This paper presents a study on selection of pivot points of links used in construction equipment. To analyze the effect of each pivot point, a design program for pivot selection is developed. A conventional pivot design method requires a complicated process because it needs to create a certain working position manually to evaluate its performance. However, the developed program includes an automatic link assembly algorithm; thus, the working device can easily be analyzed by using pivot information of links. The developed program also included a kinematic/static analysis module and characteristic analysis algorithms. Therefore, it is possible to easily analyze a working device model created through the automatic assembly algorithm, whereby users can easily analyze the effect of each link pivot point for the actual product design.

• Tribology and Lubricants
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• 제15권1호
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• pp.24-28
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• 1999

This paper describes a new pivoting technique to improve bearing performance in pivoted pad thrust bearings. This new technique adjusts the pivot line in a line pivoted pad thrust bearing to be parallel to the trailing edge of a sector shaped pad. Bearing performance factors such as load carrying capacity, frictional torque and flow rate are numerically investigated for conventional point-pivoted and line-pivoted pads and for the new parallel-line pivoting technique. It is shown that the load carving capacity can be maximized with the new technique.

• Tribology and Lubricants
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• 제5권2호
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• pp.77-82
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• 1989

The influences of ram pressure on the performances of tilting-pad journal bearings are investigated experimentally. The test rig consists of a single tilting-pad and a rotating journal. Film thicknesses and pressure distribution of the lubricating film are measured continuously for several values of coordinate of the pivot position and journal speed. The findings of the investigation are as follows: (]) According as the journal speed increases the ram pressure increases, maximum pressure decreases and the pivot position which maximize the minimum film thickness shifts toward the leading edge. (2) The ram pressure makes it possible to generate the converging wedge and the positive pressure between the pad and the journal even when the pad is supported at the points between the leading edge and the center of the pad. (3) The influence of the ram pressure on the performance of tilting pad bearings is significant and must be considered in the design of these bearings.

• 대한치과보철학회지
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• 제31권3호
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• pp.394-410
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• 1993

This study was accomplished for appreciation of the mandibular moments according to antero- posterior movement of pivot placed on the lower natural dentition. For this study, 20 subjects(male, $21\sim30$ yrs., average age 24) in the category of normal occlusion were selected, and the intraoral Vitallium clutches were cast and fabricated for each subjects. A 2-dimension PSD(Position Sensitive Detector, Hamamatsu Photonics Co., Japan) was attached to maxillary clutch in a mode of three dimensional control and LED (Light Emit Diode, Hamamatsu Photonics Co., Japan) was set up on mandibular clutch. Both clutches were set into oral cavity of each subjects and adjusted. Then the subjects were allowed to intercuspated with maximal bite force while the pivoting ball in the mid-line moving from anterior toward posterior position. The displacement scales were recorded by CCD camera(Sony, CCD-TR-705) and VCR, The conclusions were as follows : 1. When the subject was allowed to bite the metal pivoting ball in the midline of lower dentition with maximal bite force voluntarily while moving from lower central incisor to canine, 1st premolar, End premolar, 1st molar and 2nd molar. The lever actions on the pivot were revealed in all subjects. The equilibrium of moment were revealed on the pivots of 1st premolar(14 subjects), End premolar(4 subjects), and canine(2 subjects) areas. 2. The changes of loading on the TMJ according to antero-posterior positional changes of metal pivoting ball were able to recognize as follow. Compression on the TMJ was increased when the pivot moves anteriorly from the equilibrium point, and tension on the TMJ was increased when posteriorly. 3. 13 subjects were recognized their habitual chewing sides(Rights, Left8), and 7 subjects were not. During maximal biting, mandible was displaced toward their habitual chewing sides on the metal pivoting ball in the frontal plane. 4. In cephalometric analysis, the average genial angle of 20 subjects was $116.75^{\circ}$ and the average mandibular body length was 79.77mm. The equilibrium points of mandibular moment were positioned more posteriorly in the subjects having larger Genial angle than in the smaller(p<0.05). Relationships among the angle between FH plane and occlusal plane, the angle between occlusal plane and mandibular plane , and mandibular body length were not significant(p>0.05).

• 대한관절경학회지
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• 제13권1호
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• pp.1-7
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• 2009

목적: 10시 혹은 2시 방향의 경경골 대퇴 터널을 이용한 관절경적 전방 십자 인대 재건술 후 2-4년 추시 결과를 분석하고자 하였다. 대상 및 방법: 동종 경골건을 사용하여 전방 십자 인대 재건술을 시행하고 추시가 가능하였던 86예를 대상으로 하였다. 평가는 2000 International Knee Documentation Committee (IKDC) 주관적 슬관절 점수, Lachman 검사, Pivot-shift 검사, KT-1000 arthrometer 검사, 2000 IKDC 슬관절 검사 및 2차 관절경 검사를 포함하였다. 결과: IKDC 주관적 슬관절 점수는 80점 이상이 75예(87.2%), Lachman 검사상 1+ firm end 이하의 전위는 83예(96.5%), Pivot-shift 검사상 음성은 78예(90.7%), KT-1000 전방 전위 검사상 차이가 5 mm 이하인 경우는 83예(96.5%)였다. IKDC 슬관절 검사상 정상 또는 거의 정상이 80예(93.0%)였다. 2차 관절경 검사는 15예에서 시행되었으며 9예(60%)에서 전방 십자 인대 이식물의 양호한 활액막 형성을, 4예(26.7%)에서 부분적인 활액막 형성을, 2예(13.3%)에서 불량한 활액막 형성을 보였고 이식물의 실패는 1예(6.67%)가 있었다. 결론: 10시 혹은 2시 방향의 경경골 대퇴 터널을 이용한 전방 십자 인대 재건술은 전후방 안정성뿐만 아니라 회전 안정성에서 양호한 결과를 보여주었다.

• 대한기계학회논문집
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• 제12권5호
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• pp.1063-1070
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• 1988

본 연구에서는 부채꼴형 유한폭 패드베어링에서의 선단압력을 구하기 위하여 3차원 유동모델을 제시하였으며, 이 유동모델을 기초로 하여 구해진 선단압력을 패드 선단에서의 압력경계조건으로 사용하여 유막내의 압력을 구하고 베어링의 하중지지능 력, 마찰토오크 및 윤활유량등을 계산함으로써 베어링의 성능을 해석하였다. 그 결 과 선단 압력이 크게 발생하는 운전조건일수록 선단압력을 무시한 종래의 베어링 성능 해석결과와는 상당한 차이가 있었으며, 특히 관성계수가 큰 운전조건에서 사용되는 피 봇식 추력베어링에서는 선단압력의 영향으로 인하여 하중지지능력을 최대로하는 피봇 점의 위치가 패드 선단부쪽으로 크게 이동되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제22권1호
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• pp.85-91
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• 1998

In this paper, an influence of inlet pressure on the running characteristics of tilting pad thrust bearing is studied by a numerical analysis. The inlet pressure is obtained from the extended Bernoulli equation including the loss coefficient which is varied with the operating conditions. The running characteristic parameters such as the minimum film thickness, the film pressure and the film thickness ratios are calculated for various runner speeds with constant load in particular two pivot positions. The results are shown that the inlet pressure has a large influence on the minimum film thickness and other running characteristic parameters.