• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.5
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• pp.470-474
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• 1999

We have successfully grown <111>-oriented $(La,Sr)(Al,Ta)O_{3}\;(LSAT)$ mixed-perovskite single crystals and <0001>-oriented ${Ca_{8}La_{2}(PO_{4})}_{6}O_2$ (CLPA) single crystals with the apatite structure by the Czochralski method. The compositional and lattice parameter uniformity of the crystals are discussed in relation to the growth conditions. Since LSAT and CLPA single crystals have excellent lattice matching with GaN, they are promising as new substrates for the growth of high quality GaN epitaxial layers.

• 한국공간정보시스템학회:학술대회논문집
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• 2000.06a
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• pp.189-201
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• 2000

접근성이란 특정 목적을 가진 통행자가 한 지점에서 다른 지점으로 얼마나 쉽게 갈 수 있는가 를 나타내는 척도를 말한다. 따라서 접근성은 주로 공간적인 거리나 시간이 가장 중요한 요인으로 작용하며 최근에는 공간적 거리보다는 접근시간이 더 중요한 접근성 척도로 사용되고 있다. 본 연구는 GIS공간분석기법과 접근성이론을 접목하여 도시시설의 적정후보지 평가방법을 정립한 후 현재 검토되고 있는 수도권 도심공항터미널 입지 후보지 중 어떤 후보지가 이용들의 총통행시간을 최소화하는 후보 지인가에 대해 평가해보았다. 평가 결과 다음과 같은 사실을 밝힐 수 있었다. 첫째, 수도권 전체로 볼 때 평균접근시간이 가장 양호한 후보지는 쌍문터미널(현 간이 도심공항터미널)이고, 2위는 현 삼성동 도심공항터미널과 강남고속터미널, 3위는 동서울터미널과 남서울터미널 순으로 나타났다. 둘째, 수도권전체 이용자들의 총통행시간을 최소로 하는 도심공항터미널 후보지는 접근성이 가장 양호한 쌍문동터미널이 아니라 현 서울역이 1위이고, 2위는 강남고속 터미널, 3위는 용산 역으로 나타났다. 셋째, 터미널 후보지간의 가중평균접근 시간은 도심인 서울시내에 입지한 후보지와 수도권 외곽에 입지 한 후보지간에 큰 차이가 없으나 총 이용자 접근시간은 서울시에 입지한 후보지보다 외곽의 후보지가 훨씬 높게 나타나 뚜렷한 차별성을 보이고 있다. 넷째, 최적후보지 1,2,3순위 모두 서울도심과 강남도심에 입지한 지역들로 나타나 교통의 접근성 보다는 아직 인구밀집도가 주요 도시시설의 입지결정에 주요한 결정요인 되는 것으로 나타났다.해석 시스템을 구축할 예정이다. 추후에는 하수도 관망해석 컴포넌트와 하수도 업무 컴포넌트와의 통합부분에 대한 연구가 진행되어야 할 것이다.7.0로 하고 표준(標準) EDTA 용액(溶液)을 소량(少量)넣고 8N-KOH로 pH $12{\sim}13$으로 하고 N-N 희석분말(稀釋粉末)을 지시약(指示藥) 으로써 표준(標準) EDTA 용액(溶液)으로 적정(滴定)하여 Ca 치(値)를 얻었다. Ca와 Mg의 합계결정치(合計決定値)와 Ca 적정치(滴定値) 차(差)로 Mg 치(値)를 얻었다. 음(陰) ion 구분(區分)으로부터 상법(常法)에 의하여 $MgNH_4PO_4$의 침전(沈澱)을 만들어서 HCl에 녹키고 일정량(一定量)의 표준(標準) EDTA 용액(溶液)을 넣어 pH 7.0로 한다음 완충액(緩衝液)으로 pH 10으로 하고 BT 지시약(指示藥)을 써서 표준(標準) Mg $SO_4$용액(溶液)으로 적정(滴定)하여 P 치(値)를 얻었다. 본법(本法)으로 Na-phytate를 분석(分析)한 결과(結果) Na-phytate의 분자식(分子式)을 $C_6H_6O_{24}P_6Mg_4CaNa_2{\cdot}5H_2O$라고 하였을 때의 이론치(理論値)에 비(比)하여 P가 98.9% Cark 97.1%, Mg가 99.1%이고 통계처리(統計處理)한 결과분석치(結果分析値)와 이론치(理論値)는 잘 일치(一致)된다. 그러나 종래법(從來法)에 의(依)한 분석치(分析値)는 이론치(理論値)에 비(比)하여 P가 92.40%, Cark 86.80

• Restorative Dentistry and Endodontics
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• v.18 no.2
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• pp.387-394
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• 1993

In order to investigate the effects of continuous and pH cyclic remineralization, artificial enamel carious lesions were produced on sections of about 2mm thickness of bovine incisor. 0.1M lactic acid solution adjusted to a pH of 4.3 and saturity of $2.98{\times}10^{-8}$ was used as demineralizing solution. The lesions were remineralized with the solution of pH 7.0 containing 1.5mM $CaCl_2$, 0.9 mM $KH_2PO_4$ and 20mM Hepes. In continuous remineralization procedure, the specimens were immersed in remineralizing solution continuously for 72 hours. In pH cyclic remineralization procedure, the sections were immersed in remineralizing solution for 6 hours and in dermineralizing solution for 20 minutes alternately during 72 hours. The effect of remineralization was determined by polarizing microscopy and electron microprobe analysis. The obtained results were as follows. 1. In case of continuous remineralization, the lesion depth was reduced partially or unchanged. 2. In pH cyclic condition, the thichness of surface layer and the lesion depth were increased simultaneously. 3. The mineral content of lesion was recovered to the level of sound enamel by remineraiization.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.484-492
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• 2014

We quantified the effects of the composition and concentration of fertilizer solutions on the growth and nutrient uptake of 'Maehyang' strawberry at the vegetative growth stage. Acid fertilizer (AF), neutral fertilizer (NF), and basic fertilizer (BF) with concentrations of 100 or $200mg{\cdot}L^{-1}$ based on N, were formulated and applied during the 100 days after transplanting, at which point crop growth and tissue nutrient contents were analyzed. The soil solutions were sampled every two weeks to measure the pH, EC and nutrient concentrations. BF was a more effective fertilizer compared to AF and NF for growth of 'Maehyang' strawberry when fertilizer concentrations were controlled to $100mg{\cdot}L^{-1}$. By contrast, the fresh and dry weights were greatest in the NF treatment when fertilizer concentrations were controlled to $200mg{\cdot}L^{-1}$. The tissue contents of N, P, and Na were 2.20, 0.51 and 0.10%, respectively, in the NF 200 treatment, and these were the highest among all treatments tested. The highest contents of K, Ca and Mg were 2.60% in AF 200, 0.95% in BF 200 and 0.45% in BF 100, respectively. During the fertilization period, the highest and lowest pHs were 6.13 in BF 100 and 4.92 in AF 200. The lowest EC was $1.376dS{\cdot}m^{-1}$ in BF 100 and the highest was $4.936dS{\cdot}m^{-1}$ in NF 200 treatments. The highest $NH_4{^+}$ concentrations in the soil solution occurred during the AF 200 treatment, followed by those with NF 200 and AF 100. When fertilizer concentrations were equal, AF treatment gave rise to the highest $Ca^{+2}$ and $Mg^{+2}$ concentrations, followed by NF and BF, until day 84 of fertilization. The BF treatments had the highest $NO_3{^-}$ concentrations followed by NF and AF. The trends for $PO_4^{-3}$ concentrations were similar in all fertilizer treatments when the fertilizer concentrations were equal. The above results indicate that neutral and basic fertilizers were most effective to promote 'Maehyang' strawberry growth when fertilizer solutions were controlled to low or high concentrations, respectively. These findings are useful for planning fertilization programs for vegetative propagation of 'Maehyang' strawberry.

• Microbiology and Biotechnology Letters
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• v.28 no.5
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• pp.291-297
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• 2000

A strain producing high levels of compaction was isolated from soil and identified as Penicillium sp. Y-8515 based on the morphological characteristics and ribosomal RNA sequence analysis. Optimization of several different carbon and nitrogen sources for the effective production of compaction was performed resulting in the medium compositions containing 5%(w/v) glucose, 1.0 % soybean meal, 0.5% yeast extract, 0.5%(NH$_4$)$_2$$SO_4$, 0.25%,$ NaH_2$$PO_4$, 0.25% $CaCO_3$. The fixed con-centration of glucose(5%, w/v) and relatively lower concentrations(less than 2.5%, w/v) of soybean meal stimu-lated the transformation of the growth morphology from filamentous to pellet form. Comparing to that by filamentous form, the production of compactin by pellet form increased up to 1.5 folds. In a fed-batch fermentation, continuous feeding of the mixture of glucose and nitrogen source at the ratio of 10:1 showed 3.5-fold more produc-tion yield of compaction comparing to the batch mode.

• Journal of Periodontal and Implant Science
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• v.33 no.2
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• pp.311-319
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• 2003

치주조직재생을 도모하기 위한 전통적인 시술방법으로는 여러 가지 골이식재를 이용한 골이식술이 오래 전부터 이용되고 있다. 이번 실험의 목적은 장,단기간의 신생골의 형성과 CPP의 흡수를 비교하여 골이식재로서 Calcium Polyphosphate(CPP)를 평가하는 것이다. 이번 실험에 사용된 CPP는 무수 $Ca(H_2PO_4)$를 condensation하여 무결정의 $Ca(PO_3)_2$를 얻고 이를 용융하고 냉각시킨후 분쇄하여 얻은 것으로 키토산이나 $Na_2O$를 첨가한 후 3세된 비글견에 이식하여 관찰하였다. 양성 대조군으로 동결탈회건조골을 이용하였다. 조직학적으로 3개월 소견과 같이 섬유조직의 게재없이 신생골의 형성이 관찰되었다. 12개월 후의 신생골의 형성은 3개월 결과에 비해서 동결탈회건조골이나 키토산, $Na_2O$를 넣은 CPP 과립에서 더 많은 비율로 나타났다. 음성 대조군과 이식재를 넣은 군간에는 유의성이 있는 것으로 나타났고(p<0.05), 또한 키토산을 첨가한 CPP 과립과 $Na_2O$를 첨가한 CPP 과립 사이에는 신생골의 형성에 유의성이 없었다. 이식한 CPP 과립의 경우 흡수소견이 3개월 결과에 비해 크게 증가하지 않았다. 이번 실험에서는 첨가물에 상관없이 CPP 과립은 골유도성과 생체적합성을 보였다. 그러나 흡수속도가 매우 느려 신생골로 대체되는 여부를 알 수 없었다. 향후 연구에서는 흡수속도를 증가시킬 수 있는 적당한 CPP 형태와 첨가물을 밝혀내어야 할 것이다.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.447-453
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• 2019

In this study, the effect of supplying volume and frequency of a nutrient solution consisted with $NO_3-N$ 4.6, $NH_4-N$ 3.4, $PO_4-P$ 3, K 3, Ca 4.6 and Mg $2.2mmol{\cdot}L^{-1}$ on growth and fruit quality of 'Duke' blueberry was investigated. Three years old 'Duke' blueberry bushes cultivated in containers ($60{\times}80{\times}40cm$) filled with 130L peat moss and 40L pearlite (v/v) were selected for the experiment. The growth containers were mulched with sawdust. Two different volumes (4L and 8L) of nutrient solution was tested at three different supplying frequencies (one time, two times, and three times) per week and the drainage quality of nutrient solution and fruit quality of 'Duke' blueberry was evaluated. The optimal drainage rate for the vegetable cultivation is known to be 20-30%. The results revealed that the average drainage rates of 27% and 29% for the nutrient solution supplied in 'Duke' blueberry growth medium at 4L, 2 times/7 days and 4L, 3 times/7days, respectively. The highest shoot diameter (4.2mm) and shoot length (31cm) of 'Duke' blueberry was recorded with the 8L of nutrient solution supplied at 3 times per 7 days. According to the analysis of inorganic components in the drainage of nutrient solution, there was a tendency of absorbing nitrogen at the early stage of growth. The supplying volume and frequency of nutrient solution was not significantly affected on 'Duke' blueberry fruit weight, soluble solids content, and titratable acidity. The highest yield per bush (2.7kg) was recorded for the nutrient solution supplied with 4L at three times per 7 days, while the 4L nutrient solution supplied at one time per 7 days resulted the lowest yield of 1.4kg per bush. Consequently, the tested nutrient solution can be applied for the 'Duke' blueberry bushes with the volume of 4L at three times per week for the better crop growth.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.398-404
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• 1999

Factor analysis technique was employed to screen the principal indicators influencing soil and water qualities in the intensively cultivated areas of the Han River Basin. Soil chemical parameters were analyzed for the soil samples collected at intensive farming area in Pyungchang-Gun, and water quality monitoring data were obtained from the agricultural small catchments of Han River Basin during 1996 and 1997. Among the $11{\times}11$ cross correlation matrix, 29 correlations were significant out of 55 soil quality indicator pairs. The overall Kaiser's measure of sampling adequacy(KMS) value was acceptable with 0.60. Most indicators except iron were acceptable. Among soil indicators, the first factors showing high factor loadings were pH, Ca and Mg. The factor loading was the highest for Ca. The second factor could be characterized as phosphate and micronutrient. The third factor was organic matter and EC, and the fourth factor was potassium and Fe. Out of 190 water quality indicators, 86 correlations were significant. Overall KMS value was 0.74, but the KMS values for pH, TSS, Cd, Cu and Fe were lower than 50. The first factor of EC accounts 27.1 percents of the total variance, and showed high factor loadings with Na, Ca, $SO_4$, Mg, K, Cl, $NO_3$, and T-N. The second factor showed high loadings with Zn, Fe, Mn and Cd. The third to seventh factors could be characterized as $PO_4$, TSS, inorganic nitrogen, pH and T-P, and Cu factors, respectively. The factor score for EC was the highest in Kuri, followed by Chunchon, Dunnae and Daegwanryng. The factor score for heavy metals were the highest in the Daegwanryng. The results demonstrated that the factor analysis could be useful to select the most principal factor influencing soil and water qualities in the agricultural watershed.

• Journal of Preventive Medicine and Public Health
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• v.18 no.1
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• pp.59-71
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• 1985

During a period from February 1st to November 30th in 1983, measurements were made twice a month on dustfalls and concentrations of various cations ana anions in their filtrates in an urban (Heuksuk-dong, Seoul) and in a rural (Ansung) districts. Standard British Deposit Gauge method was applied for collection of dustfalls and ion chromatographic method using Ion Chromatograph 10 (Dionex, U.S.A.) for determination of cation and anion concentrations. The results obtained were as follows: 1. Annual mean values of dustfalls were $8.30{\pm}5.09tons/km^2/month$ in an urban and $6.20{\pm}0.82tons/km^2/month$ in a rural districts. And annual mean values of pH of filtrates of the collected samples were $5.3{\pm}0.76$ in an urban and $6.0{\pm}0.82$ in a rural districts. 2. Annual mean concentrations of common cations and anions in their filtrates were as follows: urban rural (unit: ppm) $$Na^{+}\;1.7{\pm}1.30\;1.9{\pm}1.86$$ $$NH^{+}_{4}\;2.4{\pm}1.60\;1.3{\pm}1.59$$ $$K^{+}\;0.7{\pm}0.47\;1.5{\pm}3.79$$ $$Ca^{++}\;5.3{\pm}0.95\;3.4{\pm}2.58$$ $$Mg^{++}\;0.7{\pm}0.89\;0.5{\pm}0.83$$ $$Cl^{-}\;2.0{\pm}1.31\;4.0{\pm}2.35$$ $$NO^{-}_{3}\;4.0{\pm}2.35\;2.7{\pm}1.31$$ $$So^{--}_{4}\;16.9{\pm}17.40\;6.8{\pm}8.00$$ Some of anions such as $Br^{-},\;{PO_4}^{-3}\;and\;{NO_2}^{-}$ were scarecely detected and $F^{-}$ was measured at very low concentrations ranging from 0.1 to 0.5 ppm in Feb., Oct. and Nov. in an urban and in Feb. in a rural districts. 3. By two-way analysis of variance with 4 replications for dustfalls, pH and concentrations of various ion by district and month of a year, statistically significant differences were noted in dustfalls (p<0.01), pH (p<0.01) and concentrations of various ion (p<0.01) by month of a year, and in dustfalls (p<0.05) and concentrations of various ion such as ${NH_4}^{+},\;Ca^{++},\;{NO_{3}}^{-}\;and\;{SO_4}^{--}$ (p<0.01) by district. 4. There were statistically significant differences pH in Spring (Feb., Mar and Apr.) (p<0.01) and in ${SO_4}^{--}$ in Autumn (Aug., Sept., Oct. and Nov.) (p<0.05) between the two districts.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.311-316
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• 2007

In this study, we investigated the presence of nitrogen, phosphorus, ions, heavy metals and other contaminations in the water stream and soil of the forest watershed with different geology and vegetations for one year from October 2004 to September 2005. Most of the nitrogen oxide in the soil was in the form of $NO_3^-$, and it appeared that nitrogen contents decreased as the soil depth increased. Nitrogen contents was highest in the basalt area showing 13.3 mg/g in the surface soil and 7.40 mg/g in the subsoil. Phosphorous contents showed no significant variations depending on the soil depth and was higher in the intermediate soil layer(60 cm) than in surface soil (30 cm) in granite and metamorphic rock areas. Nitrogenous compound in the soil water was 8.03 mg/L in the granite area of coniferous forest and 14.79 mg/L in the andesite area of the deciduous forest. Nitrogenous compound in the stream water was 5.53 mg/L in October and 6.99 mg/L in January in the granite area of the coniferous forest and $3.61\sim5.11$ mg/L in the andesite area of the deciduous forest. Phosphates in runoff and stream water were similar in coniferous with in deciduous forests, showing a slight increase(0.090$\sim$0.179 mg/L) in the basalt area. In the coniferous forest, pH showed a significant positive correlation with EC, $Ca^{2+}$ and $Cl^-$ at p < 0.01, and showed a negative correlation with S-Fe and S-Al. Electroconductivity showed a significant correlation of 0.601 with $Ca^{2+}$ and of -0.586 with $NO_3^-$ at p<0.01, and showed a significant correlation of 0.301 with $SO_4^{2-}$ and of -0.295 with S-Fe at p < 0.05. In the deciduous forest, pH showed a positive correlation with $Ca^{2+}$ at p < 0.05, and showed a negative correlation with $K^+$, S-Fe and S-Al at p < 0.01. Electroconductivity showed a significant positive correlation with $Ca^{2+}$ and $Cl^-$ at p < 0.05 and with $NO_3^-$ at p < 0.01.