• Journal of the Korean Ceramic Society
• /
• v.40 no.8
• /
• pp.804-810
• /
• 2003

The fine powder produced by heating and grinding of the waste concrete in the waste construction was investigated whether utilize as substitution raw material of SiO$_2$, CaO, and Al$_2$O$_3$ source for OPC clinker manufacture is possible or not. In order to synthesize OPC clinker, limestone, shale, converter slag and fly ash were used as main raw materials, and modulus was fixed LSF 91.0, SM 2.60, IM 1.60. The synthesized clinkers were characterized. The Main products of synthesized clinker were C$_3$S, ${\beta}$-C$_2$S, C$_3$A, C$_4$AF as OPC clinker at 1,43$^{\circ}C$. As a result of TG-DTA and burnability index(B.U) analysis of each raw mixtures, the formation temperature of clinker phases was similar and B.I was showed easy burning as 48.6∼51.4.

• The Korean Journal of Ecology
• /
• v.25 no.3 s.107
• /
• pp.145-152
• /
• 2002

Saussurea chabyoungsanica was recorded in new species by Lim Hyoung Tak in 1997. In order to understand the entity of new species, we investigated the new distribution sites, vegetation structure and soil environmental factors. Additionally discovered distribution sites of S. chabyoungsanica were Manduckbong, Mt. Sukbyoung, Mt. Duckhang, and Sukgaejae, which were located on ridge of the Taebaek Mountains. Those sites are typical limestone zones of Korea and among them Sukgaejae belongs to lower great limestone area and Manduckbong, Mt. Sukbyoung and Mt. Duckhang belong to upper great limestone area. According to the result of phytosociological study, plant communities of S. chabyoungsanica were classified by 1 Community group, 4 Communities and 2 Subcommunities; Carex humilis var. nana-Saussurea chabyoungsanica Community group in wide sense Quercus mongolica Community group, Lespedeza maximowiczii-Saussurea chabyounsanica Community, Galium kinuta-Saussurea chabyoungsanica Community, Salvia chanryonica-Saussurea chabyoungsanica Community, Zabelia coreana-Saussurea chabyoungsanica Community. Environmental factor analysis of habitat showed that the distribution site of S. chabyoungsanica was ridge of North aspect and displayed pH $7{\sim}8$ typical of limestone. Soil moisture content was high, whereas organic matter content was low. Considering its high occurrence in sites of $1{\sim}10cm$ in soil depth, and of $30{\sim}45%$ in relative light intensity, major distribution sites were outcrops and boundaries between shrubland and forest. After community division by vegetation structure in habitat of S. chabyoungsanica, we investigated characters of soil environment by community. As a result of PCA analysis of soil sample by community, it was possible to divide community by characters of soil environmental factor. The cumulative value of contribution rate represented in second dimension space was 73% and the major factors for that value were soil texture, organic matter content and field capacity.

• The Journal of the Korea Contents Association
• /
• v.12 no.12
• /
• pp.489-498
• /
• 2012

This paper consists of two parts: In the first part, we describe our work to build hierarchical knowledge base of digital library patron's research interests and learning topics in various scholarly areas through analyzing well classified Electronic Theses and Dissertations (ETDs) of NDLTD Union catalog. Journal articles from ACM Transactions and conference web sites of computing areas also are added in the analysis to specialize computing fields. This hierarchical knowledge base would be a useful tool for many social computing and information service applications, such as personalization, recommender system, text mining, technology opportunity mining, information visualization, and so on. In the second part, we compare four grouping algorithms to select best one for our data mining researches by testing each one with the hierarchical knowledge base we described in the first part. From these two studies, we intent to show traditional verification methods for social community miming researches, based on interviewing and answering questionnaires, which are expensive, slow, and privacy threatening, can be replaced with systematic, consistent, fast, and privacy protecting methods by using our suggested hierarchical knowledge base.

• The Journal of the Petrological Society of Korea
• /
• v.4 no.2
• /
• pp.91-103
• /
• 1995

The study area is located at the middle part of Daebo granitic batholith in the Gyeonggi massif. The geology of the area is mostly composed of Precambrian gneiss complex, coarse- grained middle Jurassic and fine-grained early Cretaceous biotite granites, and Cretaceous small stocks and dykes. The gneiss complex consists mainly of banded gneiss, granitc gneiss, some schist and quartzite. The coarse-grained granite can be divided into greyish granite(Gg1 in the margin and slightly pinkish granite(Gp) in the center. The former is hornblende biotite granite characterized by basic clot and xenolith. The latter is generally garnet biotite granite containing only poor basic clot. The fine-grained granite intruded the coarse-grained granite. The K/Ar biotite ages from the granites belong to middle Jurassic and early Cretaceous. The K/Ar biotite ages and geochemical compositions indicate that Gg and Gp were differenciated from a single magmatic body. The granites are calc-alkali and metaluminous-peraluminous. They are S-type(i1menite series) and partly I-type granitedmagnetite series) formed by melting of relatively fixed source composition. Their tectonic settings belong to the compressional suits and VAG of continental margin.

• The Journal of Engineering Geology
• /
• v.17 no.2 s.52
• /
• pp.187-196
• /
• 2007

The Dalseong acid mine drainage were studied focused on the characters of schwertmannite that controls geochemistry of the stream. Besides chemical analysis of stream water, particle size analysis, XRD SEM and TEM were performed on precipitates of streams and on wasted metalliferous ores. The AMD discharged from the abandoned mine reveals a decrease of pH and EC downward stream. Euhedral sulfur occurs as equigranular aggregates on the altered pyrite while fine acicula goethite coalesces to form cross, star, or starfish-like shapes. Water chemistry plotted on the Eh-pH diagram shows that schwertmannite and ferrihydrite are stable phases. Reddish brown precipitates consist of mostly schwertmannite with less goethite, whereas yellowish brown precipitates are composed of geothite with less schwertmannite. The particle size of precipitates ranges $d(0.1)\;0.861{\mu}m{\sim}3.769{\mu}m,\;d(0.5)\;3.984{\mu}m{\sim}15.255{\mu}m,\;and\;d(0.9)\;9.875{\mu}m{\sim}56.726{\mu}m$. Schwertmannite is characterized by equigranular spheric form. Pincushion or spicule with 100nm width and $200{\sim}300nm$length form on schwertmannite sphere with radial growth patterns. It is highly probable that reddish or yellowish brown precipitates formed in many AMDs may contain schwerhnannite. Because it can serve as sink for removing heavy elements by adsorption in AMD system, there is a need to correctly identify schwertmannite in precipitates and to characterize its phase stability.

• The Korean Journal of Ecology
• /
• v.25 no.2
• /
• pp.75-82
• /
• 2002

Saussurea chabyoungsanica was recorded in new species by Lim Hyoung Tak in 1997. In order to understand the entity of new species, we investigated the new distribution sites, vegetation structure and soil environmental factors. Additionally discovered distribution sites of S. chabyoungsanica were Manduckbong, Mt. Sukbyoung, Mt. Duckhang, and Sukgaejae, which were located on ridge of the Taebaek mountains. Those sites are typical limestone zones of Korea and among them Sukgaejae belongs to lower great limestone area and Manduckbong, Mt. Sukbyoung and Mt. Duckhang belong to uper great limestone area. According to the result of phytosociological study, plant communities of S. chabyoungsanica were classified by 1 Community group, 4 Communities and 2 Subcommunities; Carex humilis var. nana - Saussurea chabyoungsanica Community group in wide sense Quercus mongolica Community group, Lespedeza maximowiczii- Saussurea chabyoungsanica Community, Galium kinuta - Saussurea chabyongsanica Community, Saliva chanryonica - Saussurea chabyoungsanica Community, Zabelia coreana - Saussurea chabyoungsanica Community. Environmental factor analysis of habitat showed that the distribution site of S. chabyoungsanica was ridge of North aspect and displayed pH 7∼8 typical of limestone. Soil moisture content was high, whereas organic matter content was low. Considering its high occurrence in sites of 1∼10cm in soil depth, and of 30∼45% in relative light intensity, major distribution sites were outcrops and boundaries between shrubland and forest. After community division by vegetation structure in habitat of S. chabyoungsanica, we investigated characters of soil environment by community. As a result of PCA analysis of soil sample by community, it was possible to divide community by characters of soil environmental factor. The cumulative value of contribution rate represented in second dimension space was 73% and the major factors for that value were soil texture, organic matter content and field capacity.

• Journal of the Mineralogical Society of Korea
• /
• v.19 no.4 s.50
• /
• pp.291-300
• /
• 2006

This study has been carried out to reveal the mineralogical compositions, the concentrations of heavy metals, and related factors in the sediments of the Kumho River which is the main tributary of the Nakdong River. Even though this river flows in a short distance, it runs through different geology and industrial areas and can be a good candidate to study different geological and anthropogenic factors affecting the concentrations of heavy metals in the sediment. The major rock-forming minerals were quartz and albite. Minor amount of orthoclase, microcline, and amphybole were also identified. Clay minerals including illite, chlorite, kaolinite were associated with those minerals. In the downstream, no noticeable changes in species and amount of minerals were observed, indicating there is almost no influence on the mineralogical compositions from rock types. The concentrations of heavy metals in the sediments are in the order of Zn > Pb > Cu > Ni > Cr > Co > Cd. Following the downstream, the concentrations of heavy metals generally increase, except Pb. The regional increase of the heavy metal content is well correlated with the location of the tributary. Without changes in mineral compositions, the main factors controlling the heavy metal contents are the locations of pollutant sources. Except Pb and Ni, most of the concentrations of heavy metals were thought to be enriched by the past pollutant sources.

• Economic and Environmental Geology
• /
• v.37 no.2
• /
• pp.153-171
• /
• 2004

This study was carried out to define the geochemical and mineralogical relationship between stream sediments and regional geology on upstream of Hahn river area. Geochemical characteristic including for major elements, trace elements and rare earth elements of the South and North Hahn river bed sediments are similar to those of acid igneous rocks which are distributed around both Hahn river basin. The chemical variation of major elements against SiO$_2$ and trace elements contents between South and North Hahn river bed sediments doesn't show the difference. REE patterns of both area show a distinct negative Eu anomaly, but total contents of rare earth elements are higher in North Hahn river sediments than South Hahn river sediments. The heavy minerals in the river bed sediments in this study area are identified as tremolite-actinolite, hematiteㆍmagnetite, common hornblende, ilmenite, garnet, epidote, rutile and sphene. In conclusion, it is elucidated that South and North Hahn river bed sediments are being originated from igneous rocks or metamorphic rocks which contains medium-high grade metamorphic minerals and components of originated from sedimentary rocks those of politic or calcareous rocks are eroded away as solution or suspended load.

• Economic and Environmental Geology
• /
• v.57 no.2
• /
• pp.185-204
• /
• 2024

This study was conducted for evaluation the geological, physical, and chemical properties of domestic sand by analyzing about 4,800 quality data of natural sand from river and land area surveyed until 2023 through the aggregate resource survey conducted by the Ministry of Land, Infrastructure and Transport. The average depth of the Quaternary unconsolidated sedimentary layer in Korea, which includes a sand layer, is about 10m (maximum depth 66m). The thickness of the sand layer within the sedimentary layer is most dominant in the range of 0.5m to 4.0m. This accounts for about 70% of the entire sand layer. In the sand layer, the ratio of sand, gravel, and clay is 60:20:10. Regardless of the provenance or geology, the sand is mainly composed of quartz, plagioclase, and K-feldspar, and the minor minerals are muscovite, biotite, chlorite, magnetite, epidote. The sand includes in 45~75% of quartz, 5~20% of plagioclase and K-feldspar, each other. And other minor minerals are included in 10%. The average grain size of sand is 0.5mm to 1.0mm, which accounts for 44% of sand samples. The water absorption rate and soundness are estimated to be suitable for aggregate quality standard in almost all sand, and the absolute dry density is suitable for 66%.

• Economic and Environmental Geology
• /
• v.57 no.4
• /
• pp.417-429
• /
• 2024

To assess the effectiveness of stabilization techniques on the transfer of As and heavy metals in soil to rice plant, pot experiments were conducted using organic (biochar), inorganic (limestone-steel slag mixture), and microbiological (sulfate-reducing bacteria, SRB) stabilizers. The results showed that microbiological treatments, particularly when SRB and SO₄^2- were co-injected, achieved higher stabilization efficiencies for Pb, Cu, and Cd in soil solution by the end of the experiments (153 days). The transfer of Pb, Zn, Cu, and Cd to the rice stems, leaves, and husks was reduced across all stabilization treatments. Notably, in husks, the stabilization efficiencies of Pb, Zn, Cu, and Cd ranged from 30% to 65% for organic stabilizers and 23% to 69% for inorganic stabilizers, surpassing those achieved with microbiological stabilizers. This study highlighted the potential of SRB as an effective alternative or supplementary stabilizer to conventional options such as limestone, steel slag, and biochar in reducing the transfer of heavy metals to crops in paddy soils.