• 한국초전도학회:학술대회논문집
• /
• v.16
• /
• pp.63-63
• /
• 2006

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.431-433
• /
• 2004

해수 영향을 받은 연구지역 지하수의 특성을 수리지화학적 분석과 다변량 통계분석방법을 이용하여 고찰하였다. 수리지화학 분석 결과, 연구지역 지하수는 크게 해수와 경작 등에 의한 인간활동의 영향을 받고 있음을 알 수 있었다. Cl, Na, Mg, Ca, HCO$_3$, NO$_3$, SO$_4$, K, SiO$_2$, Sr의 농도값을 이용하여 군집분석과 주성분 분석 결과, 연구지역의 지하수는 해수의 영향을 나타내는 Na, Cl에 의해 크게 영향을 받으며 3개의 그룹으로 나누어지고, 각 그룹별로 다른 특성을 보여줌을 알 수 있었다.

• Proceedings of the KIPE Conference
• /
• 2004.07a
• /
• pp.206-209
• /
• 2004

The switched reluctance motor(SRM) drive system provides a good adjustable speed and torque characteristics. SRM has the possibility of maintaining full power over a wide speed range. So, many attempts are being done from home appliances to industrial machinery and tools. Especially, a traction drive of an SRM is one of a good application for it's DC-series characteristic. However, because of the switching mechanism it has some disadvantage of noise and vibration. It is difficult to adopt to an appliance demanding silency. A noise simulation and design of 6/4 and 12/8 SRM was done in order to compare each other.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.503-506
• /
• 2002

BSCCO 2212 HTS was fabricated by CFP(centrifugal forming process). The powder was initially ground in the mixing ratio of 2:2::1:2 with 10% of SrSO$_4$. The temperature increased up to 1035$^{\circ}C$ and 1200$^{\circ}C$ for melting. The melt was poured into the preheated and rotating copper mould from 200 to 600$^{\circ}C$. The specimen was not broken by thermal impact when the melting temperature was over 1050$^{\circ}C$ and copper mould was preheated over 400$^{\circ}C$ for 30min. A tube type of specimen was annealed at 840$^{\circ}C$ or 860$^{\circ}C$ in oxygen atmosphere for 24hours. Typical microstructure was analyzed in terms of CFP parameters by XRD, SEM, and EDS and also superconducting characteristics were compared.

• Journal of the Speleological Society of Korea
• /
• v.33 no.34
• /
• pp.7-22
• /
• 1993

본 연구에서는 단양지역에 분포한 석회암동굴계의 수질에 대한 주요 원소와 미량 원소 그리고 오염실태를 살펴보았다. 풍화물에 존재하는 미량 원소가 기반암보다 수 배 내지 수 백배 이상 부하되어 있었다. TSD와 EC 등은 화강암의 지하수 보다 높은 경향이 있었고 pH는 중성 내지 알칼리성이었다. Ca와 Mg은 기반암에서 용탈되어 지하수로 용존된 것으로 50ppm이상을 함유하고 있다. Fe과 K은 다른 주요 원소보다 현저히 낮은 경향이 있었다. 주요 음이온인 F$^{-}$ , Cl$^{-}$ , NO$_3$$^{-}$ , SO$_4$$^{-}$ 등은 환경기준치 보다도 현저히 낮은 상태이며, 따라서 오염이 안된 상태로 볼 수 있다. 미량 원소중 Al, Sr, Ba등이 높은 반면에 Co, Mo, Sb, Cs, W, Pb, U, Mn 등은 매우 극소량으로 존재하는 것으로 나타났다. 연구지역 중 온달굴, 고수굴, 천동, 노동 등지는 오염이 거의 안된 상태로 매우 양호한 편이나 천동굴은 관광객으로 인하여 일부 원소가 오염되어 있는 실정이다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.49-49
• /
• 2009

Phosphors with oxide host material, YAG:$Ce^{3+}$ and $(Ca,Sr,Ba)_2SiO_4:Eu^{2+}$ yellow phosphor, has been used for LED applications. The WLEDs using these phosphors are widely used for LCD backlighting, automobile, and general lighting applications since they have high conversion efficiency and good thermal and chemical stability which can meet necessary life time of LED products up to now. With advances of LED chip technology, the external quantum efficiency and driving current in chip get higher so that the phosphors for high power chip are required to maintain high conversion efficiency and stability at high temperature due to the heat dissipated from LED chips. In addition, higher color rendering index of LED lighting and color reproducibility of LCD than those of LEDs with single yellow phosphors are required. In order to overcome these technical issues rising from evolution of LED technology, new phosphors are in demand and nitride phosphors, one of the promising new candidate materials, will be discussed here.

• Proceedings of the KIEE Conference
• /
• summer
• /
• pp.1013-1015
• /
• 2004

SRM (switched reluctance motor) provides an excellent adjustable speed and torque characteristics. SRM has the possibility of maintaining full power over a wide speed range. So, many attempts are being done from home appliances to industrial applications. Especially, a traction drive of an SRM is one of a good application for it's DC-series characteristic. However, because of the switching mechanism and reluctance torque. it has some disadvantage of noise and vibration. It is difficult to adopt to an appliance demanding silency. Performance and noise tests with 6/4 and 12/8 SRM were excuted to compare the characteristics.

• 한국초전도학회:학술대회논문집
• /
• v.15
• /
• pp.63-63
• /
• 2005

• Spatial Information Research
• /
• v.14 no.1 s.36
• /
• pp.129-150
• /
• 2006

Mineral potential mapping is an important procedure in mineral resource assessment. The purpose of this study is to analyze mineral potential using weight of evidence model and a Geographic Information System (GIS) environment to identify areas that have not been subjected to the same degree of exploration. For this, a variety of spatial geological data were compiled, evaluated and integrated to produce a map of potential mineral in the Gangreung area, Korea. for this, a spatial database considering mineral deposit, topographic, geologic, geophysical and geochemical data was constructed for the study area using a GIS. The used mineral deposits were non-metallic(Kaolin, Porcelainstone, Silicastone, Mica, Nephrite, Limestone and Pyrophyllite) deposits of sedimentary type. The factors relating to mineral deposits were the geological data such as lithology and fault structure, geochemical data, including the abundance of Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Si, Sr, V, Zn, $Cl^-,\;F^-,\;{PO_4}^{3-},\;{NO_2}^-,\;{NO_3}^-,\;SO_{42-}$, Eh, PH and conductivity and geophysical data, including the Bouguer and magnetic anomalies. These factors were used with weight of evidence model to analyze mineral potential. Probability models using the weight of evidence were applied to extract the relationship between mineral deposits and related factors, and the ratio were calculated. Then the potential indices were calculated by summation of the likelihood ratio and mineral potential maps were constructed from Geographic Information System (GIS). The mineral potential maps were then verified by comparison with the known mineral deposit areas. The result showed the 85.66% in prediction accuracy.

• Journal of Chest Surgery
• /
• v.25 no.4
• /
• pp.347-355
• /
• 1992

The precise mechanism of the Excitation-Contraction Coupling is still uncertain. But the concept that Ca2+ induced Ca2+ release [CICR] from the Ryanodine receptor in the sarcoplasmic reticulum [foot structure] may play a major role in E-C coupling has been widely accepted since 1970`s. It is believed that increased cytosolic Ca2+ followed by CICR is main contributor for E-C coupling of striated muscle. Resulting phenomena of ischemic /post-reperfusion myocyte is increased cytosolic Ca2+, even to the absence of Ca2+ in reperfusate. So intracellular inhibitor to CICR might prevent the ischemic and reperfusion damage of myocardial cells. The relatively purified foot protein, especially heavy sarcoplasmic reticulum rich, of the skeletal muscle was incorporated into the black lipid bilayer [Phosphatidyl ethanolamine: Phosphatidyl serine=l: 1]. Under the steady state of membrane potential [+20 mV], ionic current through Ryanodine receptor was measured with Cs+ as charge carrier. In the cis chamber [Cytoplasmic side], Mg2+ strongly inhibited CICR of Ryanodine receptor[Kd=6.2 nM]. In conclusion, naturally existing intracellular free Mg2+ can inhibit CICR from intracellular Ca2+ reservior [heavy SR]. So post-ischemic or post-reperfusing myocardium could be preserved using additional free Mg2+ in cardioplegic solution or reperfusate, otherwise the optimal concentration is undetermined.