• 한국자동차공학회논문집
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• 제10권2호
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• pp.117-122
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• 2002

This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop complete analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.15-21
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• 2001

This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop an analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

• 청정기술
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• 제5권2호
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• pp.69-78
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• 1999

수용성 에멀젼형 절삭유의 한외여과 및 정밀여과 특성을 실험적으로 연구하였다. 한외여과막의 경우 오일/물 에멀젼의 투과 거동은 film model을 잘 따랐으나 정밀여과막인 ASYPOR막의 경우에는 이러한 거동을 벗어났다. 본 연구에서 사용된 모든 분리막의 경우 운전압력이 투과유속에는 큰 효과를 나타내지 않았다. 저압에서는 투과 초기 및 후기에서의 투과유속 감소율이 적은 반면 고압에서는 초기 투과유속은 매우 컸으나 투과유속의 감소율이 커서 후기에는 모두 비슷한 투과유속을 보여 주었다. 소수성이 큰 polycarbonate 정밀여과막의 경우 일반적인 경우와는 달리 운전시간이 증가함에 따라 투과유속이 증가하는 경향을 나타내었다. 교반하지 않은 cell에서의 임계투과압력은 150 ppm의 에멀젼 농도에서 약 $2.2kg_f/cm^2$이었으나 500 ppm의 농도에서는 $3.8kg_f/cm^2$ 압력에서 나타났다.

• Geomechanics and Engineering
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• 제34권1호
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• pp.17-27
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• 2023

Taking a subway shield tunnel in a certain section of Zhengzhou Metro Line 5 as an example, the field tests of shield cutting cement-soil monopile composite foundation were carried out. The load and internal force of the tunnel lining under the action of composite foundation were tested on-site and the distribution characteristics and variation laws of earth pressure around the tunnel under the load holding state of the composite foundation were analyzed. Five different load combinations (i.e., overburden load theory + q₀, Terzaghi's theory + q₀, Bierbaumer's theory + q₀, Xie's theory + q₀, and the proposed method (the combination of compound weight method and Terzaghi's theory) + q₀) were used to calculate the internal force of the tunnel structure and the obtained results were compared with the measured internal force results. The action mode of earth pressure on the tunnel lining structure was evaluated. Research results show that the earth pressure obtained by the calculation method proposed in this paper was more consistent with the measured value and the deviation between the two was within 5%. The distribution of the calculated internal force of the tunnel structure was more in line with the distribution law of field test data and the deviation between the calculated and measured values was small. This effectively verified the rationality and applicability of the proposed calculation method. Research results provided references for the design and evaluation of shield tunnels under the action of composite foundations.

• 대한인간공학회지
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• 제27권2호
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• pp.49-57
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• 2008

This study aims to investigate the effect of handle angles of pliers on performance, wrist motion and subjective rating of satisfaction. An experiment was conducted, in which handle angle of pliers was used as independent variable and 14 subjects participated. Based on the literature survey, plier handles angled at 0$^{\circ}$, 10$^{\circ}$, 20$^{\circ}$, 30$^{\circ}$ and 40$^{\circ}$ were adopted in the experiment. The subjects were instructed to bend iron plates by 90$^{\circ}$ and to cut wires as soon as possible. The results revealed that 1) handle angles of pliers have significant effect on wrist motion and satisfaction(p<0.0001); 2) handle angles of pliers did not affect performance of completing tasks irrespective of types of tasks done in the study; 3) in the initial stage of windup, plier with handle angled at 20$^{\circ}$ produced the least wrist motion of deviation in task of bending iron plates, while plier with handle angled at 40$^{\circ}$ did in task of cutting wires; 4) degree of satisfaction was maximized when handle of pliers was bent by 20$^{\circ}$ in both tasks. On the basis of the results, it is recommended that handle of pliers be bent by 20-30$^{\circ}$ for reducing musculoskeletal disorders related to pliers.

• 보건의료산업학회지
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• 제4권1호
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• pp.125-134
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• 2010

This study has been conducted to estimate the degree of cognition of military hospital services according to experience of military hospital services for serviceman, and to find out some factors affecting the medical services satisfaction. Questionnaires were given to 600 persons during October 5th though 24th 2009. All 600 questionnaires distributed affair, but 343 cases were collected. Statistical analysis methods used in this dissertation are t-test, Logistic Regression Analysis and other basic statistics such as frequency, percentage, and standard deviation using SPSS ver, 17.0. Results of the study are as follows: The satisfaction of the treat a patients' to compared military hospital and private hospital was providing free medical treatment for serviceman. The dissatisfaction of the treat a patients' to compared military hospital and private hospital was army doctors treated his very unfriendly. The level of medical treatment to providing military hospital was very low cognition for serviceman. In conclusion, to increase the preference of the military hospital is level of private hospital health care level of should be to developed. More support to financial should provide for medical workforce and setting of cutting edge medical equipment in the military hospital. Military hospital is should be competition with private hospital. Also should be improve the quality of military medical service.

• 패션비즈니스
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• 제23권6호
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• pp.27-36
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• 2019

This study aimed to analyze the color differences by warp direction of textile mosaics by focusing on two representative textile wallcovering types, woven and string. Mosaics made of string can be expressed as having three-dimensionality based on color differences resulting from the warp direction of the string. String wallcoverings, unlike woven or non-woven wallcoverings, only have vertically oriented warp lamination on the backing paper without weft, and therefore, the reflection and backing color can be expressed differently depending on the angle of the mosaic. In this study, two identical wallcoverings were manufactured using the same materials but using different textile types, woven and string. The wallcoverings underwent die-cutting by each angle and were deployed in cube form. The analysis was based on ISO 5631-1:2015. The color difference between the two wallcoverings, woven and string, was shown as ΔE* 9.29. Based on the standard deviation of the color difference for each mosaic angle, woven ranged from ΔE* 0.09 to 0.94 and string ranged from ΔE* 1.92 to 3.74, showing a larger color difference. Thus, using the color differences of string to create a mosaic wallcovering improved dimensionality.

• 한국방사선학회논문지
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• 제7권5호
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• pp.313-320
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• 2013

류마티스성 관절염 등의 관절 질환이나 내반 변형 등을 동반한 환자에게 정형외과적으로 인공슬관절 치환술을 시행하는데 수술용 금속정을 삽입할 때 대퇴체부의 휨 정도로 인해 대퇴피질부에 손상을 주거나 2차 골절 등의 부작용을 유발하기도 한다. 이때 대퇴체부의 중심 좌표값을 알면 금속정이 해부학적 모양의 중심으로 삽입될 수 있어 이러한 부작용을 예방할 수 있을 것이다. 본 연구에서는 인공슬관절 치환술이 필요한 10명의 환자와 대퇴골 질환이 없는 정상군 10명의 대퇴부 단층촬영영상을 이용하여 3차원 좌표값을 찾은 후 Matlab을 이용하여 중심좌표값을 찾아 해부학적 모양을 반영한 그래프를 얻었고, 구간별 3차원 곡률반경 값을 구하였다. 그 결과 실험군의 대퇴골 평균 곡률반경과 표준편차는 $758.15{\pm}206.3mm$로 측정되었고, 정상군은 $1672.97{\pm}395.6mm$로 측정되었다. 측정된 결과는 통계적 유의성 확보를 위해 f-검정을 실행하여 두 집단간 평균의 차이를 검증하였다. 이 결과로 미루어 실험군의 대퇴체부 휨 정도가 더 심함을 확일할 수 있었으며 이러한 영상 분석방법을 이용하여 해부학적 중심점을 찾는다면 인공슬관절 치환술 같은 정형외과적 수술에 도움이 될 것이라 사료된다.

• 한국멀티미디어학회논문지
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• 제13권9호
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• pp.1391-1398
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• 2010

애니메이션은 새로운 움직임을 창조하여 생명을 불어넣는 것이다. 정지된 이미지에 잔상의 원리를 이용하여 움직임이 인식될 수 있도록 프레임 바이 프레임(frame by frame)으로 분리 작업하는 제작방식을 이용한다. 애니메틱스(Animatics)는 바로 움직임에서 가장 중요한 타이빙과 동작을 연구하는 학문이며 애니메이션 실제 작업이 들어가기 전에 애니메이션 전체적인 분위기와 러닝타임, 그리고 스토리의 흐름을 시각적으로 살펴볼 수 있는 매우 중요한 작업일 뿐 아니라 스토리보드의 문제점을 파악하여 수정할 수 있으므로 전체적인 제작시간을 효율적으로 줄일 수 있게 하는 학문임에도 불구하고 애니메이션의 구성요소 가운데 가장 이론화 되지 못한 영역 중 하나이다. 본 연구는 애니메이션 교육 경쟁력 강화를 위하여 새로운 교과 개념으로써 애니메틱스의 접목으로 애니메이션 제작능력의 함양과 교육 방향을 제시하는데 연구의 목적을 두었다. 그리고 단순한 스토리보드의 연장이 아닌 애니메틱스 과정의 중요성을 고취하고자하며 이를 토대로 애니메이션 제작 교육이 좀 더 효과적으로 이루어질 수 있는 방안을 제시하고자 한다.

• 한국농공학회지
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• 제34권1호
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• pp.41-48
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• 1992

Various soil behaviors usually occurring in the geotechnical problems, such as, cutting and embankments, stability of slope, seepage, consolidations, shearing failures and liquefaction, should be predicted and analyzed in any way. An approach of these predictions may be followed by the development of the constitutive equations as first and subsequently solved by numerical methods. The purpose of this paper is develop the constitutive equation of sands uder monotonic or cyclic loadings. The constitutive equation which is based on elasto-plastic theory, modified anisotropic consolidated stress parameter by Sekiguchi et al and Pender's theory is derived. And the equation is included a new stress parameter, hardening function, Bauschinger's effects and Pender's theory. The model is later evaluated and confirmed the validity by the test data of Ottawa sand, Banwol sand Hongseong sand. The following conclustions may be drawn: 1. The consititutive equation which is based on elasto-plastic theory, modified anisotropic consolidated stress parpameter by Sekiguchi et al and Pender's theory is derived. The equation in included a new stress parameter, hardening function, Bauschinger's effect and Pender's theory. 2. For Ottawa sand, the result of the constitutive equation shows a better agreement than that of Oka et al. The result of axial strain agrees well with the tested data. However, the result of horizontal strain is little bit off for the cyclic loadings or large stress. It is thought that the deviation may be improved by considering Poisson's ratio and precise measurement of shear modulus. 3. Banwol sand is used for the strain and stress tests with different relative densitites and confining pressures. The predeicted result shows a good agreement with the tested data because the required material parameters were directly measurd and determined form this laboratory. 4. For Hongseong sand, the tests under same amplitude of cyclic deviatoric stress shows a similar result with the tested data in absolute strain. It shows the acute shape of turning point because the sine wave of input is used in the test but the serrated wave in prediction.