• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.431-431
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• 2012

A compact tokamak reactor concept as a 14 MeV neutron source is desirable from an economic viewpoint for a fusion-driven transmutation reactor. LAR (Low Aspect Ratio) tokamak allows a potential of high "see full txt" operation with high bootstrap current fractions and can be used for a compact fusion neutron source. For the optimal design of a reactor, a radial build of reactor components has to be determined by considering the plasma physics and engineering constraints which inter-relate various reactor components and are constrained to use ITER physics and technology. In a transmutation reactor, the blanket should produce enough tritium for tritium self-sufficiency and the neutron multiplication factor, keff should be less than 0.95 to maintain sub-criticality. The shield should provide sufficient protection for the superconducting toroidal field (TF) coil against radiation damage and heating effects of the fusion neutrons, fission neutrons, and secondary gammas. In this work, characteristics of transmutation reactor based on LAR tokamak is investigated by using the coupled system analysis.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.343-347
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• 2004

The energy injection of galactic black holes (BH) into the intergalactic medium via extragalactic radio source jets and lobes is sufficient to magnetize the IGM in the filaments and walls of Large Scale Structure at < [B] > ${\~}0.l{\mu}G$ or more. It appears that this process of galaxy-IGM feedback is the primary source of IGM cosmic rays(CR) and magnetic field energy. Large scale gravitational infall energy serves to re-heat the intergalactic magnetoplasma in localities of space and time, maintaining or amplifying the IGM magnetic field, but this can be thought of as a secondary process. I briefly review observations that confirm IGM fields around this level, describe further Faraday rotation measurements in progress, and also the observational evidence that magnetic fields in galaxy systems around z=2 were approximately as strong then, ${\~}$10 Gyr ago, as now.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.123-128
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• 2002

Over the range(OTR) has been applied for cooking and ventilation functions especially in northern Amarica. Because flow rate and operating rpm of the double sided sirocco fan for ventilation are much higher and than the microwave oven system, the major noise source is the sirocco fm. Recently, the quiet fan development is one of very important issues for amenity. In this study, the noise source identification using multi-microphone array system was carefully carried out and numerical simulations for understanding the aerodynamic and aeroacoustic of the fan were peformed. The sound level of tonal noise is predicted with a good accuracy but that of the broadband shows some discrepancy. In order to reduce the broadband noise, the inlet region of sirocco fan have to be modified that the secondary flow should be suppressed. Based on these results, new low noise fan and OTR is now developing.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.2
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• pp.190-196
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• 2007

This paper presents the 3D finite element analysis of the Contact-less Power Supply(CPS) with linear servo motor. The primary, secondary self and leakage inductances of the contact-less power supply and the capacitances of a resonant circuit are calculated by the finite element analysis using current source. The voltage source is used to do accurate analysis of the characteristics of the contact-less power supply. The CPS with the linear servo motor is proposed. The characteristics analysis of the contact-less power supply considering the linear servo motor is done.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.4
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• pp.317-325
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• 2002

An air pollution monitoring station has been operated at Tokchok Island since April 1999 to characterize the background atmosphere in the vicinity of the Yellow Sea. In this study, eight chemical species in PM$_{2.5}$ and three gaseous species were analyzed. A total of 53 samples were collected for the analysis of PM$_{2.5}$ and gaseous species from April, 1999 to April, 2001. The overall mean mass concentration of PM$_{2.5}$ was 20.8 $\mu\textrm{g}$/㎥ and the eight soluble ionic species accounted for about 46.8% of PM$_{2.5}$ mass. Approximately 80% of samples appeared to experience the chloride loss effect. Air pollutant sources of PM$_{2.5}$ measured at Tokchok Island were qualitatively identified by the principal component analysis. It was found that five principal components are secondary aerosol, soil, incineration, phase change of nitrate, and ocean.and ocean.

• Journal of Environmental Health Sciences
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• v.11 no.2
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• pp.1-16
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• 1985

There are a large number or chemical compounds that are present in a polluted atmosphere and that alone or in combination are important to consider for their potential effect on the respiratory system and impact on athletic performance. A general categorization or description of the level of pollution in terms of the concentration of one or more compounds or by type such as oxidizing compounds is inadequate and misleading. A useful initial categorization of pollutant compounds according to their mechanism of production, primary or secondary, is often made. For health effects, consideraiions of the physical state, gaseous or particulate, and the solublity and reactivity of the pollutant is also important. Pollutant compounds or substances that are emitted directly from a source and that undergo little or no chemical change in the atmosphere from source to receptor are termed primary pollutants.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.7
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• pp.1789-1798
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• 1994

This paper aimed for numerical simulation of complicated gas turbine combustor with swirler. For the convenience of numerical analysis, fuel nozzle and air linear hole areas of secondary and dilution zone, which are issued to jet stream, were simplified to equivalent areas of annular type. In other to solve these problems, imaginary source terms which are corresponded to supplied fuel amount were added to those of governing equation. Chemical equilibrium model of infinite reaction rate and $k-{\epsilon}-g$ model with the consideration of density fluctuation were applied. As the result, swirl intensity contributed to mixing of supplied fuel and air, and to speed up the flame velocity than no swirl condition. Temperature profiles were higher than experimental results at the upstream and lower at the downstream, but total energy balance was accomplished. As these properties showed the similar trend qualitatively, simplified simulation method was worth to apply to complicated combustor for predicting combustion characteristics.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.55-63
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• 1995

By employing the concept of superimposing the induced current on partial scattere roled as a secondary source, matrix Green's function was derived. The procedure in the way of derivation presented here was based on the equivalence principle and the induction theorem and applying moment methods to the resulting electric field integral equation. As examples, the induced current on scatterers consisted of wire/plate conductor, the input impedance and gain patterns of corner reflector antenna were calculated. And computing times required for solving matrix equation were compared with those of conventional method.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.611-615
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• 2003

In this paper, a operation characteristics and analysis of the HB(half bridge) inverter for remote plasma system are studied. the remote plasma system is cleaning system for the chemical vapor deposition (CVD) chamber in semiconductor processing. The remote plasma system is powered by the RF generator The main power stage of the RF generator is used for the HB PWM inverter with an low pass filter in the secondary circuit of the transformer. The detailed mode analysis of HB invertor was described. The operation characteristics of Remote Plasma Source are verified by simulation and experimental results.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1216-1222
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• 2010

Based on the MacDonald's analytic model for the diffracted sound field of a semi-infinite noise barrier, computer simulations were performed for various positions of error microphones for an active noise barrier system. The simulation process also included the effects of floor reflections on both sides of the barrier. The results were also compared with Niu's simulation results and showed a straight line arrangement of sensors and actuators, in the order of primary source, secondary source and error microphone is better than over the top arrangement of the error microphones.