• Proceedings of the KSEG Conference
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• 2004.03a
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• pp.12001-12049
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• 2004

암석의 풍화과정은 화학적인 변질, 물리적인 분해 및 생물학적인 작용으로 나뉘어 진다. 풍화에 영향을 주는 요소는 기후, 조성광물의 종류 및 구조, 절리와 단층, 열수변질작용과 광화작용, 염기성 및 산성암맥과 지형 등이다. 또한 암석의 풍화는 성인에 따라 다양한 양상으로 진행되는데 이는 암석을 이루고 있는 각각 광물들이 열역학적인 반응경로가 서로 다르고, 이에 수반되는 물리적인 풍화진행속도가 차이가 있으며, 암석의 균질성, 투수성 등이 암종별로 다양하기 때문이다. 현장에서 암석의 풍화정도는 조성광물의 변질과 분해정도를 육안 등으로 정성적으로 판단하고 분류하는 것이 일반적이다. (중략)

• Electric Engineers Magazine
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• v.229 no.9
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• pp.22-26
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• 2001

지금까지의 전력공급은 전력회사의 획일적인 품질과 요금체계로 수용가에 공급되어 왔으며 신뢰도 또한 30분 평균치의 개념으로 적용되어 왔으며 전기사용의 변화 및 사회환경의 변화로 인해 전기품질의 변동에 따른 영향이 과거와는 다른 양상을 보이고 있다.

• Environmental engineer
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• s.123
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• pp.42-43
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• 1996

중금속을 함유하는 폐수는 일반적으로 단일성분의 원소로 되어 있지 않고 여러 종류의 금속성분이나 유기물이 혼합된 상태로 발생되기 때문에 화학적인 중화나 분해로서 처리하기 곤란하므로 흡착성이 풍부한 광물질의 무기화학성분을 추출하여 흡착, 침전, 분리하는 방법을 이용할 수 있다. Aqua # 219는 폐수 처리용 약품으로 현재 사용하고 있는 설비를 일부 개조하거나 또는 기존설비를 그대로 사용하여 저렴한 가격으로 처리할 수 있는 중금속 흡착제이다.

• Journal of Korean Society for Geospatial Information Science
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• v.25 no.1
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• pp.29-36
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• 2017

In this paper, we implement a spatial big data analysis prototype based on Spark which is an in-memory system and compares the performance by the spatial split algorithm on this basis. In cluster computing environments, big data is divided into blocks of a certain size order to balance the computing load of big data. Existing research showed that in the case of the Hadoop based spatial big data system, the split method by spatial is more effective than the general sequential split method. Hadoop based spatial data system stores raw data as it is in spatial-divided blocks. However, in the proposed Spark-based spatial analysis system, there is a difference that spatial data is converted into a memory data structure and stored in a spatial block for search efficiency. Therefore, in this paper, we propose an in-memory spatial big data prototype and a spatial split block storage method. Also, we compare the performance of existing spatial split algorithms in the proposed prototype. We presented an appropriate spatial split strategy with the Spark based big data system. In the experiment, we compared the query execution time of the spatial split algorithm, and confirmed that the BSP algorithm shows the best performance.

• International Area Studies Review
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• v.13 no.2
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• pp.255-276
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• 2009

This article has examined the international transmission of returns among S&P500, Nikkei225 and SENSEX stock index cash markets using the daily closing prices covered from January 4, 2002 to February 6, 2009. For this purpose we employed dynamic time series models such as the Granger causality analysis and variance decomposition analysis based on VAR model. The main empirical results are as follows; First, according to Granger causality tests we find that S&P500 stock index has a significant prediction power on the changes of SENSEX and Nikkei225 stock index market and vice versa. However, US stock market's influence is dominant to the other stock markets at a significant level statistically. Second, according to variance decomposition, SENSEX stock index is more sensitive to the movement of S&P500 than that of Nikkei225 stock index. These kinds of empirical results shows that the three stock markets are integrated over times and these results will be informative for the international investors to build the world-wide investment portfolio and risk management strategies, etc.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.99-102
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• 2002

전기분해에 의한 부상현상을 이용하여 토양세정 후 발생되는 유출수 중의 유수를 분리하기 위한 적정 운전조건에 관하여 고찰하였다. 전압에 의한 유수분리 효율을 관찰한 결과, 전기분해 1시간 후 3V의 전압만으로도 88% 정도의 제거율을 나타내었으며 6V 이상의 전압에서는 90% 정도로 거의 비슷한 제거율을 나타내어 대부분의 에멀젼이 분리됨을 확인할 수 있었다. 동일조건에서는 전기분해 시간이 경과될 수록 분리효율이 향상되었으며, 전극 간격이 넓어질수록 같은 효율을 얻기 위해 소요되는 전압의 크기가 커짐을 알 수 있었다. 전기분해 시 양극에서는 OH$^{-}$의 방전으로 발생되는 산소에 의해 산화반응이 일어나며, 음극에서는 H$^{+}$가 방전되어 발생되는 수소에 의해 환원반응이 일어나며 미세한 기포가 형성된다. 유분의 부상분리 현상은 유분의 (-)charge와 전기분해에 의해서 발생되는 양이온의 결합으로 인한 중화반응 및 음극에서 발생되는 미세 수소기포로 인만 부상분리가 대부분을 차지하며, 전압 및 전기분해 시간이 증가하고 전극 간격이 좁을수록 음극에서 발생되는 미세기포의 양이 증가되어 부상효과가 크게 나타나는 것으로 판단된다. 전극 종류는 구리 > 알루미늄 > 철 > 티타늄 순으로 효율을 나타내었으며, 이는 양극으로 사용된 이러한 금속들의 전기전도도 차이에 의해 일어나는 현상으로 판단된다

• The Journal of Natural Sciences
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• v.12 no.1
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• pp.69-79
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• 2002

850 strains of phosphate-solubilizing bacteria were isolated from soil of Chung-nam and Daejeon region using 0.5% calcium phosphate containing medium. The HS-2 strain with the highest rock phosphate-solubilizing activity was selected and identified as Azotobacter sp. HS-2 based on the microbiological characteristics. The optimum culture temperature and initial pH of medium for solubilization of rock phosphate were $30^{\circ}C$ and pH 6.0-7.0, respectively. Addition of oxalic acid(0.5M) into the PDB-rock phosphate medium increased 50% solubilization of rock phosphate.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.1
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• pp.22-26
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• 1983

P+N and P+NN+ solar cells with the area of 3.36 $\textrm{cm}^2$ were fabricated by thermal diffusion. Under the light intensity of 100 mW/$\textrm{cm}^2$, total area(active area) conversion efficiency was 13.4%(14.7%) for P+N cell fabricated by 15 min boron predeposition at 94$0^{\circ}C$ and 20 min annealing at 80$0^{\circ}C$, and 14.3%(15.6%) for P+NN+ cell processed by 15 min boron predeposition at 94$0^{\circ}C$ and 50 min annealing at 80$0^{\circ}C$ after 20 min back phosphorus diffusion at 1,05$0^{\circ}C$. The minority carrier lifetime in bulk of P+NN+ cells was increased about 2~3 times comparing with P+N cells because of guttering and BSF effect due to back phosphorus doping. The methods used for efficiency improvement were AR coating, Ag electroplating, back doping and fine grid pattern as well as the control of front doping profile.

• Resources Recycling
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• v.8 no.5
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• pp.51-58
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• 1999

The sbdy iwestlgaled ihc propa-ties of Lhe dust\ulcorner rrom fe~~oallomya ~~ufacturTeh. e chemical composition, cornpasitlon material, p d c l e sire md shapes of the bulk dust, sired dust and magnetically separated durl were mvesligaled. As the re\ulcornerulL, we suppose that the dust from &gh Carbon Fenama~~gunesMc anuiact~vingP rocess is not sufiicient as solulce material of Mn because of ale low Mn canlenl (13.5%) and complicaled composition mate~ial. The dust from Bug F!lter or AOD Proccss is mi~inlym ade up of 0.2-2 pm Mn30, (Hausmam~iu)p iutlde in spherical shape and thc Mn content is 63.190.The dust from Cooler of AOD Process is inninly made up of coarse Ca(O1-Or)zM. n,FeyO,, SiO, and fine Mn30d.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.451-459
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• 2002

High strength flour (12.5% protein) and low strength flour (10.5% protein)were used to determine optimum formulation far steamed bread added with green tea powder (GTP). The response surface study consisted of the following independent variables : GTP (1.5∼4.5%), mixing time (8∼14 min), fermentation time (30∼50min). Bread Quality attributes measured for total bread score of each combination were loaf volume, spread ratio, surface glossiness, smoothness, grain and texture (firmness, cohesiveness, elasticity and adhesiveness). The required amount of GTP, mixing time and fermentation time for steamed bread made from two kinds of flour were different. GTP could be more added to lower strength flour than higher strength flour without losing bread quality. GTP highly affected the loaf volume, spread ratio, surface smoothness, firmness and total bread score of steamed bread (p<0.001). The results suggested that the functional steamed bread added with GTP having excellent quality can be made from low strength flour using green tea powder 3.2%, mixing time 11 min 8 sec and fermentation time 39 min 55 sec.