• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.517-523
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• 1997

We have been studied that combustion efficiency and the production of air pollution of anthracite-bituminous coal blend in a fluidized bed coal combustor. Also, the reaching time of steady state condition have been studied. This experimental results are presented as follows. As the height of fluidized bed combustor becomes higher, the concentrations of $SO_2$ and NOx mainly increased. Also, as anthracite fraction increased, the emission of $SO_2$ concentration was increased but, the variation of $NO_X$ concentration was negligible according to anthracite fraction. When anthracite fraction ratio was increased, elutriation rate was increased and exit combustible content over feeding combustible content was increased. Regardless of anthracite fraction ratio the uncombustible weight percentage according to average diameter of elutriation particles were approximately high in the case of fine particles. Over bed temperature $850^{\circ}C$ and excess air 20%, the difference of combution at the velocity 0.3m/s, bed temperature $850^{\circ}C$, the excess air 20%.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.553-558
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• 2010

To solve the problems of the low combustion activity of Korean anthracite and the abundant loss of unburned carbon in fly ash, pellet coal was fabricated from coal fines and fly ash, and the mixed combustion of coarse coal with the pellet coal was examined in the circulating fluidized bed combustor of a 0.1 MW scale test unit. In the combustion of the raw coal only, the significant amount of coal fines was entrained, resulting in overheat at the top of the combustor. With the coarse coal that most fines were eliminated, however, the combustion temperature was maintained stable. The mixed combustion of coarse and raw coals was also feasible even though it often went unstable. The mixed combustion of the coarse coal with the pellet coal was as stable as the coarse coal combustion, showing a promise that the combustion of the Korean anthracite in commercial circulating fluidized bed boilers could be further enhanced.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.335-335
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• 2010

$SiO_2$, $B_2O_3$, $Al_2O_3$, CaO, MgO, $Na_2O$, $ZrO_2$, $Bi_2O_3$를 이용하여 성질이 다른 두 종류의 무연계 프릿트를 제조하여 특성을 표준화 하였고, 이들 무연계 프릿트를 이용하여 Ag계 도체 및 $RuO_2$계 저항페이스트롤 제조하여 특성에 미치는 프릿트 조성의 영향을 연구하였다. $B_2O_3$를 첨가하여 퍼짐특성이 큰 프릿트의 경우 더 우수한 페이스트 특성을 나타내었다.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.128-132
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• 2003

무전해 Ni-P UBM과 3가지 경우의 무연 솔더간의 계면연구를 통해 Bi가 솔더의 합금원소로 들어감에 따라 계면반응에 어떠한 영향을 줄 수 있는 가를 연구했다. 3가지 다른 무연 솔더는 Bi가 각각 $0wt\%,\;4.8wt\%,\;58wt\%$들어간 Sn3.5Ag, Sn3.5Ag4.8Bi, Sn58Bi 이다. reflow를 수행한 후에 세 가지 솔더에서 나타나는 계면에서의 IMC는 $Ni_3Sn_4$로서 어떤 다른 솔더도 Bi를 함유한 IMC가 계면에선 관찰되지 않았다. 다만 SnAgBi 솔더의 경우 특이하게 솔더내에서 침상의 $Ni_3Sn_4$가 reflow후에 관찰되었다. 또한 반응속도의 척도가 되는 Ni-P UBM소모속도를 비교해 보면 reflow후의 SnAg와 SnAgBi의 경우에는 비슷하나 SnBi의 경우에는 알서 두 솔더에 비해 눈에 띠게 느림을 관찰하였다. 이러한 Ni-P UBM의 소모경향을 Bi의 함량, 그에 따른 Sn의 상대적인 함량의 관점에서 고찰하고자 한다.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.4
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• pp.373-379
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• 1998

Fly ash application with a rate 0, 50, 100, $150Mg\;ha^{-1}$ in clay loam paddy, which had properties of pH 5.3 and low contents of silicate, gave a positively residual effects on the growth of rice crop subsequent to malting barley. The responses of rice yields to fly ash application were in the order of bituminous coal fly ash(BCFA) 100 > 150 > 50 > anthracite fly ash(AFA) 50 > 100 > none > AFA $150Mg\;ha^{-1}$. As a result, yields responses of milled rice were ranged from $6.2(50Mg\;ha^{-1}){\sim}14.4%(100Mg\;ha^{-1})$ by BCFA and from $-0.6(150Mg\;ha^{-1}){\sim}6.6%(50Mg\;ha^{-1})$ by AFA showing maximum yields of 5.084 and $4.738Mg\;ha^{-1}$ by the former and the latter, respectively. Rice plant showed lodging indices ranging from $20(50Mg\;ha^{-1}){\sim}40%(150Mg\;ha^{-1})$ by BCFA and from $1.3(150Mg\;ha^{-1}){\sim}15%(50Mg\;ha^{-1})$ by AFA at harvesting stage. In especial, soils applicated with BCFA contained a good fertility in terms of pH, available $P_2O_5$ and $SiO_2$, and exchangeable Ca and Mg etc. so that possibly harbored 3yr-residual effects of the fly ash on crop subsequent to this rice.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.221.2-221.2
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• 2005

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.29.2-29.2
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• 2007

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.84-86
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• 2004

기존의 전자산업에서는 Sn-37Pb 공정솔더를 사용하였으나, 최근 납의 환경적인 문제로 인하여 무연 솔더에 관한 연구와 적용이 세계적으로 진행되고 있다. 무연 솔더의 실용화와 관련하여 Sn-37Pb 솔더와 같은 만능의 솔더는 없지만, 그 중 도입이 가장 유력시 되는 것으로 Sn-Ag-Cu계 솔더가 있다. (중략)

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.3032-3038
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• 1994

The paper discusses a combustion instability phenomena encountered in recent solid rocket motor development efforts at ADD(Agency for Defense Development). It has happened to occur as an irregular burning in development of smokeless propellant rocket motor. Through investigating the spectral analysis of accelerometer and strain gage signals which are recorded in static firing tests and acoustic modal analysis of motor inside cavity with ANSYS, the instability is found to be the second tangential mode.

• Korea Petroleum Association Journal
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• no.4 s.98
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• pp.11-13
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• 1989

ㆍ 정부는 지난 3월27일 휘발유의 특별소비세율을 보통휘발유의 경우 종전 100%에서 85%로, 무연휘발유의 경우 종전 85%에서 70%로 인하하고, 이와함께 국내 휘발유가격을 인하 조정 하였다. ㆍ 이번 국내 휘발유 가격의 조정내역을 보면, 보통 및 무연휘발유를 소비자가격 기준으로 종정의 ℓ단 402원에서 373원으로 7.2% 인하 조정하였다. ㆍ 아울러 석유가격의 점진적 자유화 조치의 일환으로 고급휘발유와 군용휘발유의 가격을 자유화 하였다.