• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.149-155
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• 2012

Purpose: Long Extension (LE) is used in proton therapy for lung and abdomen. However, it has limitations in surface area, produces collision in posterior oblique beam which creates limitations in various gantry angles in planning therapy and increases air gap (distance between patient and compensator). Therefore, this study investigates the usability of manufactured Rounded Extension (RE) in comparison to LE to use the most suitable extension in proton therapy. Materials and Methods: To compare structural features of LE and RE. This study investigated usable gantry angle for snout sizes 100, 180 and 250 and CT scanned Humanoid phantom. And it compared the air gap in posterior oblique direction. Results: The structural features of two extensions are as follow. Because of the existence of supporting bar, the width of LE was 40 cm and RE was 50 cm. Result of the investigation of usable gantry angle for snout sizes 100, 180 and 250 are as follow. LE is ${\pm}36$ (average) at 180 degree and RE is ${\pm}70$ (average). And also, the air gap of RE is decreased by 11.3 cm in average at the same gantry angle. Conclusion: Manufactured RE for proton therapy has several benefits than LE. Its therapy surface area is wider and range of usable gantry angle is also wider. Also, the air gap at the posterior oblique beam has decreased. Therefore the usability of RE in proton therapy of lung and abdomen will be increased compared to LE. However, the air gap of proton therapy at the lateral direction may be increased, so there may be need for make up to decrease air gap at the lateral direction in the future.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.797-800
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• 2004

Some test results indicated that the current ASTM grip adapter of GFRP rebar was not successful in developing the design tensile strength of GFRP rebar with reasonable accuracy. It is because the current ASTM grip adapter of GFRP rebar does not take into account the various geometric characteristics of GFRP rebar such as surface treatment, shape of bar cross section, bar deformation as well as physical characteristics such as poisson effect, elastic modulus in the transverse direction and so on. The research reported in this paper is to provide how to proportion an adequate grip adapter to develop design tensile properties of GFRP rebar. The proposed grip adapter is derived from the equilibrium or compatibility equations. From the preliminary test results for rounded GFRP rebar, it was found that the grip adapter with specific size proportioned by proposed method shows the highest tensile strength among them.

• Journal of architectural history
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• v.23 no.6
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• pp.39-46
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• 2014

In this study, we evaluated the chemical and physical properties of structural steel, which is the most basic material for steel structures and reinforcement concrete structures in modern period. We theorized the technical data for the research of technical history of modern heritage structures by analyzing the product system and its quality control of structural steel used in modern historical heritages. The results of this study are as follow; first, the rounded bars were used in most of modern heritage structures. But in the case of Waegwan railroad bridge, the deformed bars were used in spit of not using in Japan after the great earthquake of Kantou. Second, the structural steel was good in terms of quality control, but It has brittle properties because it was not manufactured by heat treatment process.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.1
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• pp.53-61
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• 1996

A clear understanding of the surface formation mechanism due to cutting is very important to help produce a good quality surface. Much of the roughness along the length of a bar being cut in a lathe can be explained in terms of macroscopic tool shape and feed rate. However, the roughness along the direction of cutting requires a different explanation. The formation of surface roughness is a problem in flow and fracture of materials in the vicinity of the tool edge. On a microscopic scale the cutting edge is rounded because it is impossible to grind a perfectly sharp cutting edge. Even if a perfectly sharp cutting edge were obtained it would soon become dull as a result of rapid breakdown and wear of the cutting edge. A research project is proposed in which in the main object is to model the surface formation mechanism due to cutting. The tool was assumed to be dull, that is, its edge has a finite radius. In order to study the effect of the radius of cutting edge on the surface formation, tools having different cutting edges were used. For orthogonal cutting experiment, cast iron and glass were chosen as brittle materials. Plowing forces acting in the cutting edge were estimated and its effect on the surface roughness was studied by observing the machined surface using optical microscope.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.566-572
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• 2011

In recent semiconductor and FPD (Flat Panel Display) manufacturing processes, high clean-class delivery operation is required more and more for short working time and better product quality. Traditionally SLIM (Single-sided Linear Induction Motor) is widely used in the liner drive applications because of its simplicity in the rail structure. A magnetically levitated (Maglev) unmanned vehicle with SLIM traction, which is powered by a CPS (Contactless Power Supply) can be a high precision delivery solution for this industry. In this paper unmanned FPD-carrying vehicle, which can levitate without contacting the rail structure, is suggested for high clean-class FPD delivery applications. It can be more acceptable for the complex facilities composed with many processes which require longer rails, because of simple rail structure. The test setup consists of a test vehicle and a rounded rail, in which the vehicle can load and unload products at arbitrary position commanded through wireless communications of host computer. The experimental results show that the suggested vehicle and rail have reasonable traction servo and robust electromagnetic suspensions without any contact. The resolution of point servo errors in the SLIM traction system is accomplished under 1mm. The maximum gap error is ${\pm}0.25mm$ with nominal air gap length of 4.0mm in the electromagnetic suspensions. This type of automated delivery vehicle is expected to have significant role in the clean delivery like FPD glass delivery.

• Journal of architectural history
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• v.28 no.2
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• pp.53-64
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• 2019

This study examines the restoration project of Sokkuram, and introduces its preliminary plans by the architect Pai Ki Hyung. The restoration project started in 1958 with an inquiry committee of the restoration project, and was completed in 1964. Despite having undergone extensive repair work under Japanese supervision from 1913 and 1923, the repair work caused water leakages inside Sokkuram, and regular cleaning work that began in 1933 caused a lot of damage to the sculpture. In result of the surveys, the top priority of this project was to protect the sculptures inside Sokkuram by improving the environment of the cave. At that time, the architect Mr. Pai participated as a head of the fourth field surveyors to plan the restoration project and to design the preliminary plans. He proposed the installation of a double dome structure to prevent further water leakages on the concrete addition that was built up around the grotto by the Japanese. However, in 1961, the Cultural Heritage Committee of Korea examined the plans of Mr. Pai and immediately rejected them. The factors of the rejection were the omitting of entrance design, system of new double dome structure that presses the existing structure, and these changes that had to be made outside of the drainage plans. The repair work of Sokkuram began in 1961, and the main construction was building double dome structure and entrance installation. In this we realize that Mr. Pai's double dome structure plans were very important key concept of this project. This study attempts to demonstrate the double dome installations that Mr. Pai initially proposed, which ultimately remains as emblematic factors of Sokkuram's legacy.