• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.401-408
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• 2021

Proton therapy using the Bragg peak is one of the radiation therapies and can deliver its maximum energy to the tumor with giving least energy for normal tissue. A cross-sectional image of the human body taken with the computed tomography (CT) has been used for radiation therapy planning. The HU values change according to the tube voltage, which lead to the change in the boundary and thickness of the anatomical structure on the CT image. This study examined the changes in the Bragg peak of the brain region according to the thickness variation in the head phantom composed of several materials using the Geant4. In the phantom composed of a single material, the Bragg peak according to the type of media and the incident energy of the proton beams were calculated, and the reliability of Geant4 code was verified by the Bragg peak. The variation of the peak in the brain region was examined when each thickness of the head phantom was changed. When the thickness of the soft tissue was changed, there was no change in the peak position, and for the skin the change in the peak was small. The change of the peak position was mainly changed when the bone thickness. In particular, when the bone was changed only or the bone was changed together with other tissues, the amount of change in the peak position was the same. It is considered that measurement of the accurate bone thickness in CT images is one of the key factors in depth-dose distribution of the radiation therapy planning.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1729-1731
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• 1999

The effect of Na on the structural and electrical properties of CIGS films were studied and their effects on the CIGS/Mo thin film solar cells were investigated. Soda-lime glass and Corning glass were used as substrates to compare the effect of Na diffusion into CIGS film. The resistivity of CIGS films was not changed in the Cu-poor region due to diffusion of Na from soda-lime glass but was mainly determined by the surface resitivity controlled by excess Na.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.134-139
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• 2006

A energy efficiency of quadruped walking robot has been studied mathematical modeling, dynamic analysis or simulation by consumption energy per period. In this paper, We used the quadruped walking robot Titan-VIII in order to carry out this experiment. The total moving length is about 2[m] , the stride length is 0.1, 0.2. 0.3, and walking period is changed by 1.0, 1.5, 2.0, 2.5 3.0[sec] Per each stride length. So consumption energy of 15 cases are measured. As a result of this experiment we obtained the best energy efficiency when stride length was 0.3[m], and Period was 1.5[sec].

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1404-1404
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• 2011

Shortage of fossil fuel energy makes current industry to find a new energy sources. One of the solutions is using the renewable energy sources like wind, sun, water, and so on. If we think with flex idea, the existing PV system's role can be greatly changed. So in this paper, I want to suggest some ideas for PV systems as one of outstanding energy source. The specific and technical explanation will be shown in the following paper in detail.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.133-139
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• 2010

From the ancient times, there are waves in the ocean. And all the moving body have energy. We have a kind of hope to convert the wave energy into electric one. Finally we can find out a power generator mechanism that mainly use the principle of pulleys. We have made drawings for this and completed the wave energy converter. This wave energy converter consists of several pulleys, rope, generator, buoys and anchors. The distance between an anchor and buoy is changed according to the hight of waves. Several sets of anchors, pulleys and buoys can make the movement of rope, and the ropes wind up a converter axis. In case of 1 meter movement of the buoy, the winding distance will be amplified 2 or 3 times if we use several moving and fixed pulleys. Based on this concept, we developed 2 kind of prototypes. One is for the test in the laboratory and the other is for the field test. Through the two test, we could confirm the usability of this mechanism.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.2
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• pp.42-49
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• 1997

This experimental study was performed to find fuel property variations of the ultrasonic energy adding gasoline and improve the spray characteristics of the multipoint injector for EFI engine. The cause and effect of the characteristic improvement of the ultrasonic energy adding fuel was found out by the chemical structure analysis (NMR, IR), distillation and viscosity test. The results are obtained that the chemical property of gasoline organizition was changed aromatics to paraffins and branch index as the physical characteristics of gasoline were improved by ultrasonic energy. There were higher distillation and lower viscosity in ultrasonic energy adding gasoline.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.969-976
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• 2007

In this thesis, an anchoring energy in the upper and lower substrates of TFT-LCD cell has been modeled and applied in the numerical calculation of the molecular orientation of the TN-LCD. The molecular orientation of liquid crystals defined as tilt and twist angles was simulated using the Newton-Raphson method and the Gaussian integration method. From the results, the tilt and twist angles for the strong anchoring energy were proven to be coincide with those of the conventional results. on the other hand, for the weak anchoring energy, azimuth angles of the molecules were changed abruptly from $0^{\circ}\;to\;90^{\circ}$ near the middle area of the cell due to the balance of the anchoring energy and the elastic energy of the liquid crystals.

• Transactions of Materials Processing
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• v.24 no.3
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• pp.181-186
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• 2015

Many in the industrial world that consume high amounts of energy are trying to reduce energy when manufacturing their products. Energy saving during manufacturing is a cost reduction. Reduced cost is necessary for profit improvement. The Piston Under Drive Brake used in the current study is an automotive transmission part. The original machining after hot forging was changed to machining after cold forging of a plate in order to save energy and cost. Two extrusion shapes along the outer diameter caused decreased tool life because of the interrupted cut during turning. Therefore, a thickness reduction of two extrusion areas in the outer diameter was needed. The current study suggests an effective way to reduce the thickness of interrupted cut by using progressive blanking.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.5
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• pp.231-239
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• 2014

This paper represents a method of existing building energy simulation using energy audit data. Energy audit must be carried out for reasonable analysis, because characteristics of existing buildings such as efficiency of fan, pump, flow rate, pressure, COP and operating schedule could be changed during the building operation. These building characteristics should be measured to estimate actual energy consumption of the existing building. In this study, we conducted energy audit and calculated energy savings for a 7-stories building as a case-study. The energy audit data were used to calibrate the building model of EnergyPlus simulation. Baseline model validated according to M&V guideline index. As a result, building characteristics are significant parameters making a big impact on energy savings in existing buildings.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.86-91
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• 2008

The structural members must be designed to control characteristics of energy absorption for protecting passengers in a car accident. Study on collapse characteristics of structural member is currently conducted in parallel with other studies on effective energy absorption capacity of structural members with diverse cross-sectional shapes and various materials. This study concerns the crashworthiness of the widely used vehicle structural members, square thin-walled tubes, which are excellent in the point of the energy absorption capacity. The absorbed energy, mean collapse load and deformation mode were analyzed for side member which absorbs most of the collision energy. To predict and control the energy absorption, controller is designed in consideration of its influence on height, thickness and width ration in this study. The absorbed energy and mean collapse load of square tubes were increased by $15{\sim}20%$ in using the controller, and energy absorbing capability of the specimen was slightly changed by change of the high controller's height.