• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.286-290
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• 2016

Background: Activation of air and water in the electron linear accelerator for medical use has not been considered severely. By the new Japanese regulation for protection of radiation hazard, it became indispensable to evaluate of activation of air and water in the accelerator room. The measurement of induced activity in air and water components in the electron energy region of 10 to 20 MeV is very difficult, because this energy region is close to the threshold energy region of photonuclear reactions. Then, we measured the photonuclear reaction yields of $^{13}N$, $^{15}O$, and $^{11}C$ by using the electron linear accelerator. Obtained data were compared with the data calculated by the Monte Carlo method. Materials and Methods: An activation experiment was performed at the Research Center for Electron Photon Science, Tohoku University. Highly purified $SiO_2$, $Si_3N_4$, and carbon disks were irradiated for 10 minutes by bremsstrahlung converted by a tungsten plate. Induced activity from C, N, and O was obtained. Monte Carlo calculation was performed using MCNP5 and AERY (DCHAIN-SP) to simulate the experimental condition. Cross section data were adopted the KAERI dataset. Results and Discussion: In our experiment in hospital, calculated values were not agreed with experimental values. It might be three possible reasons as the cause of this deference, such as irradiation energy, calculation procedure and cross section data. Obtained data of this work, calculated and experimental values were good agreement with each other within one order. In this work, we used KAERI dataset of photonuclear reaction instead of JENDL. Therefore, it was found that the photonuclear cross section data of light elements are most important for yield calculation in these reactions. Conclusion: Further improvement for calculation using a new dataset JENDL/PD-2015 and considering electron energy spreading will be needed.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1913-1914
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• 2006

Modem Industrial control systems tend to adopt a variety of intelligent wireless device controllers to interface front-end computers with active components of the industrial device. Some of the intelligent control systems come equipped with a wireless SMS(Simple Message Service) interface giving an opportunity to use fault alarm Interlock system. Immediately send warning or alert messages to Mobile devices or remote users. Real time monitoring the SMS systems by Mobile devices. Control systems remotely by mobile devices in emergency situation. In order to provide against system fault, SMS Mobile System will enable system administrator to promptly access, monitor and control the system whenever users want and wherever users are, by utilizing wireless Internet and mobile devices. This paper presents the Mobile SMS system for PAL Control System.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.715-718
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• 2005

The purpose of this paper is to investigate on hydration, setting time and compressive strength properties of cement paste mixed alkali-free accelerator using aluminum sulfate for shotcrete. The experimental focus is to variouse added element with alkali-free accelerator for shotcrete using aluminum sulfate. When diethanolamine was used as a component of alkali-free accelerator, alkali-free accelerator contributed to increasing early hydration, setting time and compressive strength properties of cement paste and mortar.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.184.1-184.1
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• 2014

Nanostructures on Graphene surface receive highly attraction for many applications ranging from sensing technologies to molecular electronics. Recently J. Jasuja et al. reported the electrical property tailoring and Raman enhancement by the implantation and growth of dendritic gold nanostructures on graphene derivatives [ACSNANO, 3, 2358, 2013] Here, we introduced Si vapor on the graphen to induce the nanostructure. The surface property change of graphene by controlling the amount of Si and the thickness of graphene were investigated using high resolution photoemission spectroscopy (HRPES), and atomic force microscopy (AFM). The Si nanostructures on graphene show the thickness dependency of graphene, and the size of Si nano-structure reached to 7 nm and 15 nm on the mono and the multilayered graphene after $30{\AA}$ Si evaporation.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2189-2191
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• 1999

To improve the reliability of the klystron-modulator systems, the stable operations of the thyratron an important factor of the system are required. The thyratron always has a possibility of self-fire according to the conditions of the applied high voltage and this induces the system fault. Therefore a command charging method was introduced to reduce the applied tim8 of the high voltage into the thyratron. The high voltage switch used in the command charging method is the SCR (1.6 kV, 50A) and consists of 10 SCRs in series to discharge 10 kV. A pulse transformer was used to apply the trigger pulse. The objectives of this research are the fabrication of the semiconductor switch and the study of the experimental result of the operation characteristics of the high voltage semiconductor switch.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2123-2125
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• 2000

A multi-gap pseudospark is high power switching with a wide dynamical voltage range. The pseudospark system has been operated at the voltage of 5$\sim$20 kV and the pressure range of 35$\sim$80 mtorr. The switching current of the pseudospark switch was measured as 106 kA for 3 gaps. 124 kA for 4 gaps, 120 kA for 5 gaps. The current duration is about 0.9${\mu}s$ in each multi-gap switch. To obtain the characteristics of the switch, this paper describes the results of tests.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2129-2131
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• 2000

The thyratron is a very important device in the modulator as the high power switch but there is no method to diagnose the inside of the thyratron. The thyratron always require ranging, maintaining of the proper pressure, for the optimum operation of the thyratron. But, up to now this only depends on the experience of the operator. In this paper, we discuss the diagnostic of the thyratron by the convection heat current and the principle and experimental data will be compared for the automatical adjustment of optimum gas pressure of the thyratron at the intial stage.

• Journal of information and communication convergence engineering
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• v.1 no.1
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• pp.48-52
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• 2003

A cost efficient IPSec Accelerator board utilizing a crypto chip and an entry-level Linux PC for the high performance VPN is presented in this paper. The IPIP (IP-over-IP tunneling) processing, encryption & decryption processing, HASH processing, and the integrity test functions of IPSec are processed in the IPSec Accelerator board. The proposed IPSec Accelerator has demonstrated successful execution of the required functions of the IPSec packet processing and verified its performance by processing the IPSec packets at the rate of over 1 Gbps.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.97-99
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• 2014

포항가속기 연구소에서 4세대 전자를 가속시키기 위하여 RF 공급원으로 사용하는 펄스 모듈레이터의 고전압 안정도는 50ppm 이하의 고전압이 요구된다. 200 MW 모듈레이터에 공급하기 위하여 개발된 고전압 CCPS사양은 50 kV, 120 kJ/sec, 2400mA, 20ppm이하이다. XFEL용 모듈레이터는 고정밀 고전압 CCPS를 적용하여 운전하였으며 모듈레이터 사양은 400kV, 500A, 8us, 60Hz, beam voltage stability 0.005(%)이다. 본 논문에서는 개발한 고정밀 고전압 CCPS를 사용하여 시험한 모듈레이터의 시험 결과에 대하여 발표하고자 한다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1090-1091
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• 2007

전자빔은 전자석의 자기장에 의하여 궤도가 편향 또는 집속된다. 이 전자석에 사용되는 전원장치는 사용되는 부품들의 품질과 관련되는 제어 기술의 발전으로 성능이 크게 향상되고 있다. 이 논문에서는 DSP를 이용하여 IGBT를 구동하는데 있어 phase-shifting 기법을 적용한 병렬 운전으로 출력 특성이 크게 개선된 전원장치에 대하여 설명하였다. 이 장치의 기본사양은 ${\pm}\;350\;A$, 2.5 Hz 계단형태의 출력전류를 전자석에 제공하는 것이다. 출력전류 피드백과 입력전압 피드-포워드 제어구조를 적용하여 출력전류의 안정도를 개선하였다. 모의실험과 실제 전자석 구동실험을 통하여 개발된 전원장치가 다양한 용도에 편리하게 적용될 수 있음을 보여준다.