• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.249-254
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• 1992

This research was conducted to investigate the effects of fly ash applications on growth and yield parameters of corn (Zea mays L.), and soil chemical properties. Corn height at silking stage, and height and dry matter ratio at harvesting stage were enhanced by applications of fly ashes derived from bituminous coal and anthracite, respectively. Effects of fly ash treatment on growth parameters of corn were varied with kinds and levels of fly ash application and growth periods, but relatively small without revealing a major negative effect as compared to the control. Yield of corn was increased by applying fly ash of anthracite origin, but other yield components were not influenced negatively by fly ash treatment. Soil total carbon contents, cation exchange capacity, and phosphorus contents of soils sampled after harvest of corn were significantly increased by fly ash treatment, although there were slightly different effects according to kinds and levels of fly ash application. Exchangeable cations of soils were varied within an experimental error range. Phosphorus taken up by corn was enhanced by treating fly ash of the bituminous coal to the soil and there were a positive correlation between phosphorus uptake and soil Phosphorus level. Cation uptake by corn was changed a little, but no significant reduction was observed in cation uptake due to fly ash treatment. It seems to be difficult to figure out the mechanism of fly ash effects on growth and nutrient uptake by corn with one year field experiment, however treatment of fly ash enhanced some parameters of growth and yield, and nutrient uptake by corn without revealing any major negative effects. To determine the value of fly ash as a fertilizer source, continuous researches under various soil and crop conditions were considered to be necessary.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.144-150
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• 2006

Chemical characteristics and their interrelationships of 156 soils included by 74 sandy loam and 82 loam soils collected from plastic film house in Chungbuk area were investigated from 1998 to 2001. Seventeen chemical properties including pH, organic matter (OM), electrical conductivity (EC), inorganic nitrogen, available phosphorus, exchangeable cations, CEC, etc., were analyzed by correlation, standardized partial regression coefficient, and principal factor analysis. Standardized partial regression coefficients of chemical properties were estimated to determine the degree of contribution of EC and OM contents in soils. Principal factor analysis was applied to classify the studied chemical properties into different groups having similar chemical properties. The pH of experimental soils ranged from 4.24 to 7.14 and 4.95 to 7.35 for loam and sandy loam soils, respectively. The EC of soils varied from 0.93 to $15.65dS\;m^{-1}$ for loam and $0.91{\sim}22.30dS\;m^{-1}$ for sandy loam soils, respectively with significant differences among them. The EC measured by 1:5 $H_2O$ dilution method and saturation method were significantly related with 8.163 and 8.599 as the slopes of regression equation for loam and sandy loam soils, respectively. These slopes more than 8.0 in this regression equation was higher than the slope of 5.0 that is estimated from dilution coefficient suggesting that EC measured by 1:5 dilution method might be erratic. The standardized partial regression coefficient of different chemical properties for the estimation of EC was in the order of $NO_3{^-}$ > $Cl^-$ > OM > exchangeable Mg for loam soils and $NO_3{^-}$ > exchangeable Mg > $Cl^-$ for sandy loam soils. Contribution order of the chemical properties based on standardized partial regression coefficient differed 1:5 dilution method and saturation method, indicating that different chemical compounds might be present in the extract solutions of these two methods. Consequently the measurement of EC by saturation method was thought be still better for estimation of chemical property because accuracy of EC measurement by 1:5 dilution method can't be improved by any specific coefficient for adjustment of EC. Regardless of differences in soil textures and extraction methods, correlation coefficients between EC and the other chemical properties were routinely in the order of $NO_3{^-}$ > $Cl^-$ > degree of base saturation > exchangeable Mg > exchangeable Ca > $SO{_4}^{2-}$. The principal factor analysis revealed four factor groups of the chemical properties studied. The groups for sandy loam were as follows; ; 1. salt components, 2. soil reaction components, 3. fixed and adsorption components, 4. CEC components. The groupings of loam soils were similar to sandy loam except that exchangeable Na substituted the CEC of sandy loam.

• Korean Journal of Materials Research
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• v.7 no.4
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• pp.347-353
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• 1997

BaTiO$_{3}$물질은 뛰어난 유전체로 널리 알려져 왔으며 특히 Heywang등이 제안한 PTCR특성은 이 물질의 응용범위를 세라믹 필터, 회로보호소자, 온도감지소자 및 저항가열장치 등으로 확대시켰다. 이러한 특성의 발현기구는 아직까지 밝혀지지 않은 상태이지만 제 특성을 향상시키기 위한 노력은 계속되어왔다. 특히 개발목적에 맞게 온도에 따른 정저항 특성(PTCR; Positive temperature constnat of resistivity phenomena)을 설계하려는 시도가 계속되어 왔으며 그 중에서도 페로브스카아트계의 2가와 4가의 양이온 자리를 등가나 원자가가 다른 양이온으로 치환하여 특성을 개선하려는 시도가 계속되어 왔다. 특히 $Ca^{2+}$나 Sr$^{2+}$는 $Ba^{2+}$자리를 치환할 수 있는 물질로 개별적인 첨가에 대한 연구는 많은 연구자들에 의해 진행된 상태이지만 최종적인 영향이나 해석에 대해서는 연구자들간에 이견이 많은 상태이다. 이번 실험에서는 BaTiO$_{3}$계에 합성한 (Ca, Sr)TiO$_{3}$를 Ca와 Sr의 상대적인 비를 변화시키면서 전체적인 첨가량을 변화시켜 그에 따른 전기적 특성 및 미세구조를 살펴보았다. (Ca, Sr)TiO$_{3}$의 첨가로 상온저항 및 PTCR특성을 변화시킬 수 있었으며 이를 통해 PTCR물질의 활용범위를 넓힐 수 있는 발판을 마련할 계기가 되었다. 특히 기존의 연구가 주로 개별적인 Ca나 Sr의 첨가에 의한 미세구조와 전기적 특성변화의 연구에 치중해 있었던 것과는 달리 Sr과 Ca을 함께 치환하여 상대적인 비가 특성에 더 중요한 영향을 끼치는 것을 확인하였으며 적절한 합성비를 선택하면 퀴리온도에서의 저항변화폭을 유지하면서 상온저항을 낮출 수 있음을 확인하였다.문했던 연구소인 Shanghai Research Center of Biotechnology, Shanghai Institute of Industrial Microbiology 및 Scientific Research Institute of Food and Fermentation Industry을 소개하고저 한다. 짧은 기간의 방문이라 주로 해당연구소의 자체소개 자료를 중심으로 방문하면서 느낀점을 기술하고저 한다.초염기성암 기원의 사문암이 열수변질작용을 받아 생성되었음을 명확하게 지시하며, 따라서 활석 광석내에 존재하는 녹니석은 활석의 근원 광물로서 녹니석편암 및 녹니석 편마암 매의 녹니석이 활석화되고 남은 잔존광물이 아니라, 주변암에 의해 성분상의 영향을 받은 열수와 사문암과의 변질교대작용에 의한 활석화과정 중에 주로 생성된 것으로 추정된다. 이러한 결과는 연구지역의 활석광상이 초염기성암의 사문암화 작용과 활석화 작용의 두 가지 변질작용에 의해 형성되어졌음을 알려준다.농도 증가 없이 폐 조직에 약 50배 정도의 고농도 cisplatin을 투여할 수 있었으며, 또한 분리 폐 관류 시 cisplatin에 의한 직접적 폐 독성은 발견되지 않았다이 낮았으나 통계학적 의의는 없었다[10.0%(4/40) : 8.2%(20/244), p>0.05]. 결론: 비디오흉강경술에서 재발을 낮추기 위해 수술시 폐야 전체를 관찰하여 존재하는 폐기포를 놓치지 않는 것이 중요하며, 폐기포를 확인하지 못한 경우와 이차성 자연기흉에 대해서는 흉막유착술에 더 세심한 주의가 필요하다는 것을 확인하였다. 비디오흉강경수술은 통증이 적고, 입원기간이 짧고, 사회로의 복귀가 빠르며, 고위험군에 적용할 수 있고, 무엇보다도 미용상의 이점이 크다는 면에서 자연기흉에 대해 유용한 치료방법임에는 틀림이 없으나 개흉술에 비해 재발율이 높고 비용이 비싸다는 문제가 제기되고 있는 만큼 더 세심한 주의와 장기 추적관찰이 필요하리라 사료된다.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.3
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• pp.181-188
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• 2007

Objective of this research was to identify by-product composting impacts on paddy soil properties and rice yield. Research was conducted in Iksan (soil was identified as a Jeonbug series) located in Honam plain area from 2001 to 2004. Composts, such as cow manure sawdust compost(CMSC), Chicken manure sawdust compost(ChMSC) and Pig manure sawdust compost(PMSC) were treated in the reseach plots for every, 2, and 3 year term. Some physical properties, such as, soil hardness, and bulk density tended to decrease with application of compost and decreased in order of CMSC, ChMSC, and PMSC, while surface soil depth and porosity were increased in order of CMSC, PMSC, and ChMSC. Some chemical soil properties, such as organic matter, available phosphorus, available silicate, and exchangeable cations were increased with application of compost and every year application plots. Nitrogen uptake was higher in order of CMSC, ChMSC, SF, and PMSC. Nitrogen use efficiency was higher in order of CMSC, ChMSC, SF, and PMSC. Rice yields was increased in all application plot of CMSC, in every other year application plot ChMSC and PMSC compared with SF($5.07Mg\;ha^{-1}$). Also average rice yield on years were increased in all application plot of CMSC and in every other year application plot ChMSC, while decreased in all application plot of PMSC compared with SF($5.27Mg\;ha^{-1}$). Head rice ratio and perfect grain ratio on hulled rice was high in all application plot of PMSC and in every year, in every other year app lication plot of ChMSC while its lowered percentage of 10~13 caused by application of CMSC compared with SF.

• Korean Journal of Ecology and Environment
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• v.34 no.1 s.93
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• pp.20-29
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• 2001

The amount, chemical composition and optical property of extracellular dissolved organic carbon (EOC) by phytoplankton were examined using axenic cultures of Microcystis aeruginosa, Anabaena flos-aquae, and Oscillatoria agardhii. The extracellular organic matter was categorized into five fractions (hydrophobic acids; AHSs, hydrophobic neutrals; HoNs, hydrophilic acids; HiAs, hydrophilic bases; HiBs, and hydrophilic neutrals; HiNs) using three adsorbent resins(XAD-8, cation, and anion). The release pattern and chemical composition of EOC varied with algal species and their growth phases. Percentage of extracellular release increased with age in all cultures. HiAs were the dominant component of EOC in all cultures, whereas the proportion of HiAs decreased with age in all cultures. In contrast, the proportions of HiBs and HiNs increased as cultures aged. In particular, the HiN fraction increased from 0% to 44% of EOC in M. aeruginosa and from 3.0% to 28% in A. flos-aquae, respectively. The proportion of AHSs was higher in the cultures of A. flos-aquae(7.5${\sim}$16%) and O. agardhii (8.7${\sim}$16%) than M. aeruginosa(0.2${\sim}$2.5%). The proportions of AHSs increased with culture age in M. aeruginosa and O. agardhii, but decreased in A. flos-aquae. The specific UV absorbance also varied among species; 1.9 Abs${\cdot}$cm$^{-1}$/mgC${\cdot}$L$^{-1}$ for M. aeruginosa, 3.7 Abs${\cdot}$cm$^{-1}$/mgC${\cdot}$L$^{-1}$ for A. flos-aquae, and 13.0 Abs${\cdot}$cm$^{-1}$/mgC${\cdot}$L^{-1}$ for O. agardhii. The results of this study indicates that DOC excreted by three blue-green algae differed with species and the growth phase.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.79-85
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• 1991

This study reports on the physical and chemical properties of the whole soils (<2mm) derived from five major rocks of granite, granite-gneiss, limestone, shale, and basalt in Korea. The properties were considered from the kind and frequency distribution of rock-forming minerals in the parent rocks. In particle size distribution, sand fractions were high in the soils from granite-gneiss, silt fractions mainly, in the residual soils from limestone, shale, and basalt. And clay fractions were particularly high in the colluvial soil from limestone and the old alluvial soil from basalt. pH, extractable Ca and Mg, and cation exchange capacity of the soils derived from limestone might be considered to be high due to the presence of sand and/or silt-sized calcite and dolomite inherited from the parent rocks. However, the soils derived from granite and granite-gneiss, being abundant in feldspars, quartz, and micas, showed a tendency to the contrary. A soil from shale composing of high quartz tended to have pH. extractable Ca, base saturation, and low exchangeable Al. In total element analysis, the soils derived from parent rocks with high contents of (i) orthoclase and micas, (ii) biotite, primary chlorite, and augite, and (iii) carbonate minerals and plagioclase as a rock-forming mineral showed a tendency to decrease the contents of $K_2O$, $Fe_2O_3$ and MgO, and CaO in comparison with those of their parent rocks.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.235-241
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• 2003

The effect of ultraviolet (UV) radiation on the characteristics of algae-derived dissolved organic matter (DOM) was examined by comparing the biodegradability and DOM fraction distribution of algal DOM before and after UV exposure. Algal DOM from two axenic cultures of Microcystis aeruginosa and Oscillatoria agardhii were irradiated for 24 h at a UV intensity of 42 W/$m^2$. A complete degradation of algal DOM during the UV exposure did not occur, remaining at constant concentrations of dissolved organic carbon(DOC). After UV exposure, however, microbial degradations were reduced by 17% in M. aeruginosa and 53% in O. agardhii, respectively, and decomposition rates also were two times lower in UV exposed algal DOM. In addition, the chemical compositions of algal DOM altered substantially after UV radiation exposure. The proportions of hydrophilic bases (HiB; protein-like DOM) decreased considerably in both algal DOM sources after UV exposure (16.8% and 20.0% of DOM, respectively), whereas those of hydrophilic acids (HiA; carboxylic acids-like DOM) increased as much as the decrease of the HiB fraction. Capillary ion electrophoresis (CE) analysis showed that several carboxylic acids increased significantly after UV exposure, further confirming an increase in HiA fractions. The results of this study clearly indicate that algal DOM can be changed in its chemical composition as well as biodegradability without complete degradation by UV radiation.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.134-139
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• 1985

This study was designed to understand the relationships among the soil physical and chemical properties and to obtain the useful regression to calculate the cation exchange capacity, field capacity, wilting point moisture content and organic matter content. Fourteen soil properties were collected from 315 representative soil series in Korea. Simple and multiple regression were analyzed with the data by grouping land use, drainage class and soil depth. The multiple regression equations which can be calculated the cation exchange capacity from clay and organic matter content were found out. Cation exchange capacity of clay was 22me/100g, and that of organic matter was 103.3me/100g. Moisture retentions, both of wilting point moisture content and field capacity, were closely related to clay and organic matter content. The coefficient of clay was increased with drainage class changed more poor but the coefficient of organic matter was highest at moderately well drained soil. Organic matter content can be calculated by soil texture and pH. Organic matter content was decreased by in creasing the pH. The highly significant regressions were found between base saturation and pH.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.1
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• pp.10-16
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• 1991

Mean values and the relative contribution of OM and clay to total CEC for soil textural classes were obtained from the analytical results of the typical profiles(sample size : 3,182) which were described by the detailed soil maps througthout Korea with an exception of Jeju island. The results are below. 1. Mean values of the soil CEC were 2.9 for S, 4.7 for LS, 6.7 for SL, 9.0 for L, 10.2 for SiL, 10.7 for CL, 8.6 for SCL, 12.2 for SiCL, 16.1 for SiC, and 17.4me/100gr for C, respectively. 2. The multiple regression equation and partial regression coefficient tended to show that OM and clay had the highly significant effect on CEC. 3. Clay content of the coarse, moderately coarse, and moderately fine soil was 1.10 to 1.89 times as important as OM content whereas OM of the medium and fine soil 1.09 to 2.94 times as important as clay in predicting CEC. 4. Mean values of CEC of the humus and clay in Korean soils were about 62.9 and 24.0me/100gr, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.272-279
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• 1997

Chemical properties of soils and mineral contents in plants grown at seventy one regions located in southern part of Korea were surveyed to obtain the basic information for sustainable management of plastic film house soils. The averaged soil chemical properties showed optimum levels in pH, organic matter, available boron, manganese, zinc contents, whereas available phosphate and exchangeable rations were highly accumulated. Available phosphate showed highly positive correlation with continuous cropping period. The contents of phosphate, potassium, calcium, and magnesium in the top soils were ranged from 912(Pusan)~1.796mg (Masan) ; $1.52(Pusan){\sim}2.93cmol^+$(Sunchon) ; $7.44(Masan){\sim}18.58cmol^+$(Changweon) ; $2.82(Changnyong){\sim}6.24cmol^+/kg$(Changweon), respectively. There were high levels of phosphorus and potassium in the leaves of plastic film house plants of pepper, cucumber, pimento, chrysanthemum, and carnation. And calcium and magnesium were more than two fold high in fruiting vegetables than flowering plants showing antagonistic utilization against potassium.