• 한국해안·해양공학회논문집
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• 제23권6호
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• pp.401-406
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• 2011

본 연구에서는 3차원 수치파동수조에서 무반사 조파시스템을 이용한 경사입사파의 조파방법을 새롭게 제안하고, 계산된 수면변위 및 수평유속에 대한 수치결과와 Stokes파의 3차 근사이론값과의 비교 분석을 통하여 새로운 모델의 검증을 실시하였다. 그 결과 본 연구에서 제안한 경사입사파의 조파방법의 타당성과 유효성을 확인할 수 있었다.

• The Journal of Korean Physical Therapy
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• 제27권4호
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• pp.196-200
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• 2015

Purpose: The purpose of this study was to examine the muscle activity of the trunk muscles during balance exercises on a stable and unstable surface in patients with stroke. Methods: Thirteen subjects (8 males, 5 females) with stroke were enrolled in the study. Muscle activity was recorded using surface EMG electrodes from the affected side of the erector spinae, external oblique, and internal oblique muscles. The exercise was performed under three conditions. For the first condition for balance exercise, subjects were instructed to sit on an exercise mat with legs extended. The second condition was to sit with legs extended, with a balance pad under their buttocks. The third condition was to sit with legs extended, have a balance pad under the buttocks and a balance cushion under the lower legs. Results: This study showed significant differences in EMG activities during both arm lifting exercise and weight shifting exercise between conditions. This study showed that the EMG activities of the erector spinae, external oblique, and internal oblique muscles were significantly higher when the trunk exercise was performed using the balance pad with balance ball than when using the stable surface. Conclusion: In conclusion, performing balance exercises using an unstable surface is a useful method for facilitating trunk-muscle strength and hence trunk stability.

• International Journal of Precision Engineering and Manufacturing
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• 제4권4호
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• pp.19-24
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• 2003

In end milling process, which is characterized by the use of a rotating tool, the undeformed chip thickness varies periodically with phase change of the tool. Although many efforts have concentrated on the study of end milling process, the analysis of shear and chip-tool friction behaviors has not been reported. Recently, a model has been proposed to simulate the shear and friction characteristics of an up-end milling process in terms of the equivalent oblique cutting. In the current study, the varying undeformed chip thickness and the cutting forces in a down-end milling process are replaced with the equivalent ones of oblique cutting. Then it is possible to simulate the shear and the chip-tool friction characteristics of a down-end milling process. The proposed model has been verified through two sets of cutting tests i.e., down-end milling and the equivalent oblique cutting tests. The experimental results show that the proposed model is suitable to analyze the shear and chip-tool frictional characteristics of down-end milling process. The specific cutting energy decreases with increase in equivalent undeformed chip thickness in a down-end milling process.

• 대한핵의학회지
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• 제20권1호
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• pp.53-58
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• 1986

Thyroid scans using $Na^{131}I\;and\;^{99m}TcO_4^-$ in two (anterior and anterior oblique) projections were done simultaneously in 50 patients with single palpable nodule and in euthyroid state(nodular nontoxic goiter) and 20 normal subjects to evaluate the imaging ability of each radionuclide and the necessity of oblique view. In detection of a nodule as a cold or cool area, $^{99m}TcO_4^-$ was slightly superior to $^{131}I$(82 % to 78% with anterior view alone, 92% to 84% when oblique view is added in detectability), with addition of an oblique view, 5 more cold or cool area in $^{99m}Tc$ scan and 3 more $^{131}I$ scan were detected. In normal subjects $^{99m}TcO_4^-$ scan was significantly superior to $^{131}I$ scan(90% to 70%) in getting normal pattern of tracer uptake in the glands. For routine imaging study of the thyroid, $^{99m}Tc$ pertechnetate scan with multiple projection is considered to be a preferable method.

• 한국디지털건축인테리어학회논문집
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• 제3권1호
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• pp.39-49
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• 2003

The height provisions, by the urban planning, describe the hightest height per width division, also define oblique line limitation by road without mentioning the highest per width division. Therefore this study will be a basic model for the standard of measuring the highest height per width division analysizing the propriety of current standard of oblique limitation. This technique is prepared to prevent the confusion and to complements the existing planning method. Therefore, it takes more time to establish this new method and to apply it to the existing condition. This study reviewed density control in District Units Plan, based on the guidelines of density, which included height, ratio of total floor to ground area, and land distribution. This study aims to provide efficient analysis by using current oblique limitation provisions Thus, proving the area rations of general residential areas are decreasing. Since the purpose of the District Units Plan is to avoid confusion and help ease the existing problematic conditions which have risen from the two above-mentioned conventional systems, further observation and research on these areas are necessary.

• Current Optics and Photonics
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• 제4권3호
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• pp.193-199
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• 2020

In this paper we propose a dark-field digital holographic microscopy system based on 360-degree oblique illumination. This setup is constructed without using a dark-field objective. The principle of 360-degree oblique illumination of vortex beam and dark-field digital holographic microscopy are introduced theoretically and experimentally. By analyzing the reconstructed image of a dark-field digital hologram of a USAF 1951 target, it is proved that the imaging resolution can be improved by this method. And also, comparison and analysis are made on the reconstructed image of a bright-dark field digital hologram of a pumpkin stem slice, the result shows that the imaging contrast is also enhanced with this method, and it is effective for dark-field digital holographic microscopy imaging of large transparent biological samples.

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권1호
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• pp.69-84
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• 2018

In order to analyze the characteristics of propeller exciting force, the hybrid grid is adopted and the numerical prediction of KCS ship model is performed for hull-propeller-rudder system by Reynolds-Averaged Navier Stokes (RANS) method and volume of fluid (VOF) model. Firstly, the numerical simulation of hydrodynamics for bare hull at oblique state is carried out. The results show that with the increasing of the drift angle, the coefficients of resistance, side force and yaw moment are constantly increasing, and the bigger the drift angle, the worse the overall uniformity of propeller disk. Then, propeller bearing force for hull-propeller-rudder system in oblique flow is calculated. It is found that the propeller thrust and torque fluctuation coefficient peak in drift angle are greater than that in straight line navigation, and the negative drift angle is greater than the positive. The fluctuation peak variation law of coefficient of side force and bending moment are different due to various causes.

• 대한기계학회논문집A
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• 제26권10호
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• pp.2114-2121
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• 2002

In order to study the effects of oblique tabs on the in-plane shear properties of unidirectional carbon fiber reinforced aluminum laminate composites, the 10$^{\circ}$off-axis tensile test, the 45 $^{\circ}$off-axis tensile test and Iosipescu shear test were performed to determine the shear properties. Off-axis tension test was studied by using new oblique-shaped tabs proposed by Sun and $Chung^{(7)}$. Iosipescu shear test was studied by using modified Wyoming test fixture. The oblique tabs reduced remarkably end-constraint effects of off-axis specimens with a aspect ratio of about eight. The experimental results show that there is no significant difference between off-axis test results and those of Iosipescu shear test. The 45$^{\circ}$off-axis tensile tests are recommended for the determination of the shear properties of unidirectional carbon fiber reinforced aluminum laminated composites.

• Steel and Composite Structures
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• 제34권2호
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• pp.227-239
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• 2020

The aim of this study is to obtain the nonlinear and post-buckling responses of relatively thick functionally graded plates with oblique elliptical cutouts using a new semi-analytical approach. To model the oblique elliptical hole in a FGM plate, six plate-elements are used and the connection between these elements is provided by the well-known Penalty method. Therefore, the semi-analytical technique used in this paper is known as the plate assembly technique. In order to take into account for functionality of the material in a perforated plate, the volume fraction of the material constituents follows a simple power law distribution. Since the FGM perforated plates are relatively thick in this research, the structural model is assumed to be the first order shear deformation theory and Von-Karman's assumptions are used to incorporate geometric nonlinearity. The equilibrium equations for FGM plates containing elliptical holes are obtained by the principle of minimum of total potential energy. The obtained nonlinear equilibrium equations are solved numerically using the quadratic extrapolation technique. Various sets of boundary conditions for FGM plates and different cutout sizes and orientations are assumed here and their effects on nonlinear response of plates under compressive loads are examined.

• 한국추진공학회지
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• 제23권5호
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• pp.10-18
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• 2019

Center Body Diffuser (CBD)의 Center Body (CB) 형상에 의한 유동 특성 및 시동압력을 해석하였다. CB 위치와 Cone 각도의 변경을 통해 초음속 유동 특성 및 시동압력을 비교하였다. CB 위치를 변수로 하여 Diffuser 해석한 결과, 유동의 모멘텀의 형성에 따라 강한 경사충격파의 발생위치가 달라지는 것을 확인하였다. 또한 경사충격파가 발생할 경우, 초음속 유동의 방향이 디퓨저 벽면으로 유도되는 것을 확인하였다. Cone 각도 변화에 따른 경사충격파의 각도 차이로 인하여, CBD의 시동압력이 영향을 받는 것을 확인하였다.