• Corrosion Science and Technology
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• 제5권6호
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• pp.201-205
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• 2006

HYPER(Hybrid Power Extraction Reactor) is the accelerator driven subcritical transmutation system developed by KAERI(Korea Atomic Research Institute). HYPER is designed to transmute long-lived transuranic actinides and fission products such as Tc-99 and I-129. Liquid lead-bismuth eutectic (LBE). Has been a primary candidate for coolant and spallation neutron target due to its appropriate thermal-physical and chemical properties, However, it is very corrosive to the common steels used in nuclear installations at high temperature. This corrosion problem is one of the main factors considered to set the upper limits of temperature and velocity of HYPER system. In this study, a parametric study for a corrosion model was performed. And a preliminary corrosion model was also developed to predict the corrosion rate in isothermal Pb and LBE flow loops.

• 대한방사선치료학회지
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• 제6권1호
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• pp.89-93
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• 1994

Authors have measured virtual source distance of electron beam from CL/1800 medical linear accelerator, with newly designed method. Beam scanning was performed with the direction of beam axis in the air. Compared results between this study and well established in phantom measurement shows good agreement with in experimental error. And we have found that build-up cap plays very important role in air measurement because of charge build up. The method of in-air measurement of virtual source distance is very easy to set-up and generate accurate results.

• 전자공학회논문지B
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• 제28B권9호
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• pp.712-718
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• 1991

In this paper, we propose a graphic system for high speed generation of bitmap font data from the outline font data such as PostScript, etc. In desk-top publishing system. A VLSI chip called KAFOG was designed for the high-speed calculation of a cubic Bezier curve, which was implemented in 1.5\ulcorner CMOS gate array using 17,000 gates. A cubic Bezier curve is approximated by a set of line segments in KAFOG at the throughput of 250K curves per second with the clock frequency of 40 MHz. A prototype graphic system was developed using two MC6800 microprocessors and the KAFOG chip. Two microprocessors cooperate in a master and slave mode, and handshaking is used for communication between two processors. KAFOG chip, being controlled by the slave processor, operates as a coprocessor for the calculation of the outline font. The throughput of the prototype graphic system is 40 64$\times$64 outline fonts per sencond.

• Applied Science and Convergence Technology
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• 제25권3호
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• pp.47-50
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• 2016

Low temperature test for half-wave resonator (HWR) cryomodule is performed at the superfluid helium temperature of 2 K. The effective temperature is defined for non-uniform temperature distribution. Helium leak detection techniques are introduced for cryogenic system. Experimental set up is shown to make the low temperature test for the HWR cryomodule. The cooldown procedure of the HWR cryomodule is shown from room temperature to 2 K. The cryomodules is precooled with liquid nitrogen and then liquid helium is supplied to the helium reservoirs and cavities. The pressure of cavity and chamber are monitored as a function of time. The vacuum pressure of the cryomodule is not increased at 2 K, which shows leak-tight in the superfluid helium environment. Static heat load is also measured for the cryomodule at 2.5 K.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.269-269
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• 2012

A new ion source has been designed, fabricated, and installed at the NBTS (Neutral Beam Test Stand) at the KAERI (Korea Atomic Energy Research Institute) site. The goalis to provide a 100 keV, 2MW deuterium neutral beam injection as an auxiliary heating of KSTAR (Korea Super Tokamak Advanced Research). To cope with power demand, an ion current of 50 A is required considering the beam power loss and neutralization efficiency. The new ion source consists of a magnetic cusp bucket plasma generator and a set of tetrode accelerators with circular copper apertures. The plasma generator for the new ion source has the same design concept as the modified JAEA multi-cusp plasma generator for the KSTAR prototype ion source. The dimensions of the plasma generator are a cross section of $59{\times}25cm^2$ with a 32.5 cm depth. The anode has azimuthal arrays of Nd-Fe permanent magnets (3.4 kG at surface) in the bucket and an electron dump, which makes 9 cusp lines including the electron dump. The discharge properties were investigated preliminarily to enhance the efficiency of the beam extraction. The discharge of the new ion source was mainly controlled by a constant power mode of operation. The discharge of the plasma generator was initiated by the support of primary electrons emitted from the cathode, consisting of 12 tungsten filaments with a hair-pin type (diameter = 2.0 mm). The arc discharge of the new ion source was achieved easily up to an arc power of 80 kW (80 V/1000 A) with hydrogen gas. The 80 kW capacity seems sufficient for the arc power supply to attain the goal of arc efficiency (beam extracted current/discharge input power = 0.8 A/kW). The accelerator of the new ion source consists of four grids: plasma grid (G1), gradient grid (G2), suppressor grid (G3), and ground grid (G4). Each grid has 280 EA circular apertures. The performance tests of the new ion source accelerator were also finished including accelerator conditioning. A hydrogen ion beam was successfully extracted up to 100 keV /60 A. The optimum perveance is defined where the beam divergence is at a minimum was also investigated experimentally. The optimum hydrogen beam perveance is over $2.3{\mu}P$ at 60 keV, and the beam divergence angle is below $1.0^{\circ}$. Thus, the new ion source is expected to be capable of extracting more than a 5 MW deuterium ion beam power at 100 keV. This ion source can deliver ~2 MW of neutral beam power to KSTAR tokamak plasma for the 2012 campaign.

• 한국방사선학회논문지
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• 제14권2호
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• pp.97-104
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• 2020

방사선이 조사된 흰쥐의 간에서 아로니아의 방사선 방호효과가 나타나는가를 혈청검사를 통하여 알아보고자 하였다. 실험동물은 (체중 200~250g) 수컷 흰쥐 5마리씩, 1군으로 정상군, 5 Gy 방사선대조군은 2군, 5 Gy 방사선조사 아로니아 실험군은 3군으로 설정하였다. 정상군 1군(A)은 일반식을 투여하고 방사선 조사를 실시하지 않고, 대조군 2군(B)은 일반식을 투여하여 방사선 조사를 하였고, 실험군 3군(C)는 방사선조사 전 14일 동안 아로니아, 경구투여량(100 mg/kg/day)로 1일 2회씩 50 mg/kg/day로 증류수에 희석하여 각각 흰쥐에 14일 동안 쥐용 존데를 이용하여 경구투여 후 방사선조사를 실시하였다, 이 연구를 위해서 Linac (선형가속기) 6 MV X선 치료장치를 사용하여 5 Gy 방사선이 1회 전신조사 된 흰쥐의 혈액을 채취하여 간에 관련된 5가지 혈청검사를 실시하였으며, 통계분석은 분산분석(ANOVA test)를 실시하였다. 결론적으로 실험분석을 확인한 결과는 아로니아의 간에 대한 방사선방호 효과가 없는 것으로 나타났다. 그러나 통계적으로 ALB (P > 0.05)는 유의성이 없고, TP (P < 0.05)는 유의한 차이가 있다고 확인되었다. 향후에는 다양한 검사가 이루어져야 할 것으로 사료된다.

• 대한방사성의약품학회지
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• 제7권2호
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• pp.119-125
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• 2021

⁸²Sr for ⁸²Rb generator was produced through the irradiation of the proton beam on the ^nat.RbCI target at the target irradiation facility installed at the end of the Rl-dedicated beamline of the 100 MeV proton linear accelerator of KOMAC (Korea Multi-purpose Accelerator Complex). The average current of the proton beam was 1.2 µA for irradiation time of 150 min. For the separation and purification of the ⁸²Sr from ^nat.RbCI irradiated, Chelex-100 resin was used. The activities of ⁸²Sr in the irradiated ^nat.RbCI target solution and after purification were 45.29 µCi and 43.4 µCi, respectively. The separation and purification yield was 95.8%. As an adsorbent to be filled in the generator for ⁸²Sr adsorption hydrous tin oxide was selected. The adsorption yield of ⁸²Sr into the generator adsorbent was > 99 %, and the total amount of ⁸²Sr adsorbed to the generator was 21.6 µCi as of the day of the ⁸²Rb elution experiment. When the elution amount was 22 mL, the maximum⁸²Rb elution yield was 93.3%, and the elution yield increased as the flow rate increased. After the eluted ⁸²Rb was filled in the correction phantom of the small PET for animals, a PET image was taken. The image scan time was set to 5 min, and the phantom PET image was successfully obtained. As results of impurity analysis on eluted ⁸²Rb using ICP-MS, ^nat.Rb stable isotopes that compete in vivo of ⁸²Rb were identified as undetected levels and were determined to be No-Carrier-Added (NCA).

• Radiation Oncology Journal
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• 제9권1호
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• pp.143-152
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• 1991

본 논문에서는 소조사면에 대한 X-선의 선량분포를 일반실험식으로 계산될 수 있도록 beam 측정 데이타를 종합 처리하는 방법에 대하여 기술하고 있다. Beam 데이타는 philips LINAC 6 MV, 8 MV X-ray에 대하여 측정 되었으며, 측정된 요소는 tissue maximum ratio (TMR), off-axis-ratio (OAH), 그리고 relative output factor (ROF)를 포함한다. 소조사면에 의한 방사선 치료를 위하여 isocenter에서 지름이 1 내지 3cm되도록 실린더 형태의 특수 collimator가 2 mm 간격으로 제작되었다. 본 측정을 위하여 다이오드 detector가 이용되었으며 Film 및 TLO 측정기로 측정된 값과 비교검토 되었다. 제한된 조사면으로 측정된 TMR, OAR data로부터 beam 데이타를 나타내는 실험식을 유도하였으며 이 실험식은 임의의 Set-UP조건에 따른 측정값을 예상할 수 있는 일반 실험식으로 확장되었고 측정된 TMR과 OAR 값들은 잘 일치되었다.

• 한국의학물리학회지:의학물리
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• 제17권4호
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• pp.207-211
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• 2006

kV cone-beam CT (CBCT)가 결합된 선형가속기의 등장으로 더욱 정확한 영상유도 방사선치료(Image-guided radiation therapy, IGRT)가 가능해졌다. IGRT는 영상장비를 이용해 표적의 이동을 보정할 수 있는 방사선치료기술로, CBCT를 이용한 IGRT의 경우 내부 장기의 정보를 바탕으로 병변의 이동을 정확히 알 수 있다. 내부 장기의 정보를 얻기 위해서는 방사선이 조사되기 바로 전에 환자의 CBCT 영상을 획득하여 치료계획 시 사용한 모의치료 CT영상과 정합을 수행하게 된다. 본 연구에서는 CBCT 영상의 재구성 품질에 따른 정합결과를 비교해 보았다. 6명의 환자로부터 총 56개의 CBCT 투과 정보를 획득하여 분석한 결과, 평행이동벡터의 차가 1 mm를 초과하는 경우는 단 3개에 불과하였다. 회전이동의 경우, x, y, z, 세 축을 모두 고려하였으며, 그 결과 총 168 ($56{\times}3$)개에서 단 3개만이 $1^{\circ}$ 이상의 차이를 나타냈다.

• International Journal of Automotive Technology
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• 제4권1호
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• pp.41-45
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• 2003

The 42V Mild Hybrid System has been released into market by Toyota for the first time in the world in 2001. The set-up employs an inverter unit to control the motor/generator (MG) electronically. The driving system called such as Toyota Mild Hybrid System (TMHS) has additional new functions to conventional internal combustion engines. When stopping vehicle, the engine stops promptly. When starting vehicle, by releasing the brake pedal MG starts the vehicle at the same time (EV-driving mode). When stepping on the accelerator pedal, or after a given period of time the engine firing occurs and the engine-driving mode starts. When running by motor, the power is supplied to the motor from 36V battery through the inverter. High outputs and instant responses are required for Inverter. At the same time, the compact volume is required to fit into the limited space of the engine room. The compact size and high output are also required to Power Capacitor used for this inverter. The power capacitors has been newly developed, shaped in "flat" type, suitably for the inverter. The points of developments on inverter and power capacitor are described in this paper.his paper.