• International Journal of Precision Engineering and Manufacturing
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• v.4 no.4
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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.

• The Korean Journal of Nuclear Medicine
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• v.20 no.1
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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.

• Journal of The Korean Digital Architecture Interior Association
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• v.3 no.1
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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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• v.4 no.3
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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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• v.10 no.1
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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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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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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• v.34 no.2
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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.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.5
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• pp.10-18
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• 2019

In this study, flow characteristics and the starting pressure of a center body diffuser (CBD) were analyzed at various center body (CB) positions and cone angles. According to the CB position, the location of oblique shock moved to the front from behind the CB cone with an increase in the flow momentum. Additionally, when a strong oblique shock occurred, the direction of supersonic flow was affected and induced to diffuser wall. As a function of different cone angles for the oblique shock, the starting pressure of the CBD was significantly affected.

• The Journal of Korean Physical Therapy
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• v.31 no.4
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• pp.193-198
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• 2019

Purpose: This study examined the effects of plank exercise combined with breathing and arm exercises on the external oblique, internal oblique, and transverse abdominal muscle thickness. Methods: Thirty healthy adults consisting of 12 males and 18 females from K area were divided into a plank exercise combined with breathing and arm exercises group (n = 15) and a plank exercise only group (n=15). The changes in muscle thickness before the exercise and four and eight weeks after the exercise were analyzed using a two-way repeated analysis of variance (ANOVA). The significance level was set to ${\alpha}=0.05$. Post-hoc t-tests were conducted to detect the interactions between the time and groups, and the significance level was set to ${\alpha}=0.01$. Results: According to the experimental results, the external oblique abdominal muscle showed significant differences over time (p<0.05). The internal oblique abdominal muscle also showed significant differences over time and in the interactions between the time and groups (p<0.05). The transverse abdominal muscle showed significant differences over time, in the interactions between time and groups, and in the changes between the groups (p<0.05). Conclusion: The results indicated that plank exercise combined with breathing and arm movement exercises led to increases in the abdominal muscle thickness. These types of exercises may be useful in lumbar stabilization rehabilitation treatment.

• Wind and Structures
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• v.32 no.2
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• pp.105-114
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• 2021

This paper describes a wind tunnel test on a 1:25 scale model of TTU building with several adjustable openings in order to comprehensively study the characteristics of fluctuating internal pressures, especially the phenomenon of the increase in fluctuating internal pressures induced by tangential flow over building openings and the mechanism causing that. The effects of several factors, such as wind angle, turbulence intensity, opening location, opening size, opening shape and background porosity on the fluctuating internal pressures at oblique wind angles are also described. It has been found that there is a large increase in the fluctuating internal pressures at certain oblique wind angles (typically around 60° to 80°). These fluctuations are greater than those produced by the flow normal to the opening when the turbulence intensity is low. It is demonstrated that the internal pressure resonances induced by the external pressure fluctuations emanating from flapping shear layers on the sidewall downstream of the windward corner are responsible for the increase in the fluctuating internal pressures. Furthermore, the test results show that apart from the opening shape, all the other factors influence the fluctuating internal pressures and the internal pressure resonances at oblique wind angles to varying degrees.