• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.365-368
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• 2006

The objective of this research is to investigate usage of 3KW photovoltaic-wind power hybrid generation system composed of 500W solar power generator and 400W wind power generator in a parallel circuit. In addition, solar radiation meter and wind monitor have been installed into each generation system to obtain the practical operating data that monitored in monthly, daily and hourly. These data that are independent to weather change and location would provide adequate generation output on average and cope with emergency situation in generation system In conclusion, based on this study, it could be considered for 3KW combined generation system to be gradually propagated to houses and small-size public facilities.

• Journal of IKEEE
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• v.15 no.2
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• pp.129-133
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• 2011

A spread spectrum clock generation is an efficient way to reduce electro-magnetic interference (EMI) radiation in modern mixed signal chip systems. The proposed circuit generates the spread spectrum clock by directly injecting the modulation voltage into the voltage-controlled oscillator (VCO) current source for SATA II. The resulting 33KHz modulation profile has a Hersey-Kiss shape with a rounded peak. The chip has been fabricated using $0.18{\mu}m$ CMOS process and test results show that the proposed circuit achieves 0.509% (5090ppm) down spreading at 1.5GHz and peak power reduction of 10dB. The active chip area is 0.36mm ${\times}$ 0.49mm and the chip consumes 30mW power at 1.5GHz.

• Progress in Superconductivity and Cryogenics
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• v.2 no.1
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• pp.7-13
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• 2000

A rotating cryogenic system was designed similar to the cooling system for the rotor of a superconducting generator. The experimental rotor has an inner vessel which simulates the winding space of an actual superconducting rotor, and a torque tube of comparable design. This paper describes the evaluation of the total heat leak into the inner vessel that leads to the study of the heat transfer characteristic of the rotating cryogenic system. To examine the insulation performance of the experimental rotor. temperature was measured at each part of the system at various rotaing speeds from 0 rpm to 600 rpm. Total heat leak into the inner vessel was calculated by measuring the boil-off rate of liquid helium. Conduction heat leak to the inner vessel was obtained by the vent tube, and radiation heat leak was calculated by subtracting the conduction heat lent from the total heat leak. There seemed to be no rotaional dependency of total heat leak at least up 600 rpm.

• Journal of radiological science and technology
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• v.20 no.1
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• pp.55-59
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• 1997

The quality of continuous X-ray beam depends upon the half value layer which varies according to the geometric conditions, filtration thickness, and tube voltage. We compared the inverter type X-ray equipment with the conventional single phase 2 peak and the three phase 12 peak for the quality obtained by changes of the added filter thickness and the tube voltage. The quality of single phase 2 peak X-ray generator showed increase for the added filter and the tube volt-age. The half value layer is Increased the thicker the filter and the higher the kVp. The quality of the Inverter type and the three phase 12 peak in comparison with the single phase 2 peak X-ray generator is increased.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.6
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• pp.1138-1143
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• 2011

One of the critical items in radar testing is the ability to evaluate the performance of radar systems under real operational environments. But it takes lots of time and cost to operate real targets and analyze the test results due to a large amount of data based on these complicated environments. In this paper, the Radar Simulative T&E Lab. is introduced, and the test and analysis results of the developing radar for predicting the radar system performance are described in the Radar Simulative T&E Lab. This laboratory could be used to test the far-field characteristics of antenna radiation pattern and to perform an effective radar system test and evaluation using a simulative target generator under a low cost repeating test situation.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1970-1978
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• 2021

The aim of this study was to optimize the target, moderator, and collimator (TMC) in a neutron beam generator for the accelerator-based BNCT (A-BNCT) system. The optimization employed the Monte Carlo Neutron and Photon (MCNP) simulation. The optimal geometry for the target was decided as the one with the highest neutron flux among nominates, which were called as angled, rib, and tube in this study. The moderator was optimized in terms of consisting material to produce appropriate neutron energy distribution for the treatment. The optimization of the collimator, which wrapped around the target, was carried out by deciding the material to effectively prevent the leakage radiations. As results, characteristic of the neutron beam from the optimized TMC was compared to the recommendation by the International Atomic Energy Agent (IAEA). The tube type target showed the highest neutron flux among nominates. The optimal material for the moderator and collimator were combination of Fluental (Al₂0₃+AlF₃) with ⁶⁰Ni filter and lead, respectively. The optimized TMC satisfied the IAEA recommendations such as the minimum production rate of epithermal neutrons from thermal neutrons: that was 2.5 times higher. The results can be used as source terms for shielding designs of treatment rooms.

• Journal of IKEEE
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• v.18 no.4
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• pp.544-551
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• 2014

This paper suggests an algorithm to measure low-level radiation by radiation measuring devices, and the other algorithm to improve reaction speed of the device to better respond to dramatic changes in radiation amount. The former algorithm to improve the accuracy of measuring low-level radiation takes advantage of a dual window radiation measurement method which is based on accumulated average of pulses gathered by a radiation measuring sensor. The latter algorithm is to enhance reaction speed of a measuring device to more sensitively react to dramatic changes in radiation amount by adopting a dual window radiation measurement method which analyzes data patterns newly put into for six seconds. To verify the suggested algorithms, a hardware-which consists of sensor and high-voltage generator, controller, charger and power supply circuit, wireless communication part, and display part-was used. Tests conducted on the dual window radiation measurement method as used in the suggested algorithm have proved that accuracy improves to measure low-level radiation of 5uSv/h, and linearity also gets better. Other tests were conducted to see whether the suggested algorithm enhances the reaction speed of a radiation measuring device so that the device responds better to dramatically changing radiation amount. The experimental results have shown meaningful changes in numbers after six seconds. Therefore, the conclusions are made that the algorithm enhances the reaction speed of the device.

• Journal of the Korean Society of Radiology
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• v.8 no.3
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• pp.105-110
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• 2014

Diagnostic radiation equipment diagnosis and treatment of disease of recent plays a central role, but this is based on the assumption of an appropriate balance of benefits and risks of diagnostic. If balance is not maintained has the potential to give an adverse effect on the health of the public. In the case of an overseas, the importance of (QA) quality assurance of medical equipment is growing, but evaluation criteria of quality assurance has not been clearly presented in domestic. Therefore, the modernization of medical equipment from the point at which the degree of cycle-by-cycle management system of foreign national to be suitable for diagnostic radiation generator entry and quality control standards by introducing a tailoring is necessary. In this study the most frequently used diagnostic radiation generator X-ray imaging apparatus of the general three-year periodic inspections at any time between the periodic inspection items and quality control methods and standards for the establishment of the United States, Canada and abroad, and international electronic literature search Technical Committee (International Electro-technical Commission, IEC) were compared with the provisions of item. Based on the national quality control items when opening frequent inspection items and standards presented as a basis for setting up study.

• Journal of Radiation Protection and Research
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• v.31 no.4
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• pp.165-171
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• 2006

In Korea, a real-time effective dose measurement system is in development. The system uses 32 high-sensitivity MOSFET dosimeters to measure radiation doses at various organ locations in an anthropomorphic physical phantom. The MOSFET dosimeters are, however, mainly made of silicon and shows some degree of energy and angular dependence especially for low energy photons. This study determines the correction factors to correct for these dependences of the MOSFET dosimeters for accurate measurement of radiation doses at organ locations in the phantom. For this, first, the dose correction factors of MOSFET dosimeters were determined for the energy spectrum in the steam generator channel of the Kori Nuclear Power Plant Unit #1 by Monte Carlo simulations. Then, the results were compared with the dose correction factors from 0.652 MeV and 1.25 MeV mono-energetic photons. The difference of the dose correction factors were found very negligible $(\leq1.5%)$, which in general shows that the dose corrections factors determined from 0.662 MeV and 1.25 MeV can be in a steam general channel head of a nuclear power plant. The measured effective dose was generally found to decrease bit $\sim7%$ when we apply the dose correction factors.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.336-344
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• 2011

The purpose of this study is to analyze the radiation-pattern characteristics above 1 GHz for the electromagnetic wave radiated from multi-slot such as ventilations, etc. on the enclosure of an EUT and so to make recommendations for suitable test methods. An experimental EUT was formed by putting a comb-generator at the center of a rectangular enclosure with 4 slots, and its radiation pattern was analyzed in the frequency range of 1~6 GHz. As analysis results, multi-lobe appears above 2 GHz and the number of multi-lobes is growing as the frequency increases. And real radiated-emission measurements were performed for the experimental EUT by scanning a receiving antenna in the height of 1~4 m and tilting toward maximum radiation, as well as setting the height of a receiving antenna to the central position of the EUT which is prescribed at the present standards. The measured results are +12.8 dB in the scanning and +16.4 in the scanning and tilting compared with the present standard test method. Therefore, the latter must be revised in order to consider the radiation pattern above 1 GHz.