• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.5
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• pp.12-18
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• 1975

Triac phase controlled pre-regulator를 이용한 직류안정화전원에서 제어소자 전력소모를 촤소로 줄이기 위하여, 부하전류의 증가에 따라 제어소자 양단전압을 낮추어 주는 회로를 고안하여 부가하였다. 이렇게 하므로써 제어소자의 전력소모가 약 40%정도 감소되어 방열장치가 간단해지거나 전력용량을 증가할 수 있게 되었으며 열발산이 곤란한 monolithic I.C.화에 유용하도록 하였다. A method on minimizing the power dissipation in the control element of a series D.C. voltage regutator is devised. An additional control circuit which reduces the average voltage drop across the control element according to increasing the load current is attached :o the trial phase controlled pre-regulator system. It is verified that the power dissipation in the control element is reduced up to 40% by this. circuit arrangement. The heat sink system can be simplified and the capacity of tile handling power is also increased. It is expected that this circuit arrangement can be applied to I.C. fabrication.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.191-199
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• 2011

The char burn-out and NOx emissions from sub-bituminous coal were investigated in drop tube furnace under $O_2/N_2$ and $O_2/CO_2$ environments with different $O_2$ concentrations of 12, 21 and 31%. Results show that the char burn-out rate is faster as $O_2$ concentration increases higher and char burn-out rate under $O_2/CO_2$ decreases due to the lower oxygen diffusion into coal surface through the $CO_2$ rich boundary layer. NO concentration increases with increasing $O_2$ concentration, but declines at $O_2$ concentration of 31%. Meanwhile, NO emission indexes decreases monotonically with increasing $O_2$ concentration, which indicates that more NO reduction occurs with higher $O_2$ concentration probably due to greater HCN formation. For all conditions of $O_2$ concentration, the NO concentration under $O_2/N_2$ maintains higher than those of $O_2/CO_2$ due to presence of thermal NO.