• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.920-924
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• 2012

This study was performed to estimate total contents of arsenic (As) by stepwise multiple-regression analysis using chemical properties and extractable contents of metal in paddy soil adjacent to abandoned mines. The soil was collected from paddies near abandoned mines. Soil pH, electrical conductively (EC), organic mater (OM), available phosphorus ($P_2O_5$), and exchangeable cations (Ca, K, Mg, Na) were measured. Total contents of As and extractable contents of metals were analyzed by ICP-OES. From stepwise analysis, it was showed that the contents of extractable As, available phosphorus, extractable Cu, exchangeable K, exchangeable Na, and organic mater significantly influenced the total contents of As in soil (p<0.001). The multiple linear regression models have been established as Log (Total-As) = 0.741 + 0.716 Log (extractable-As) - 0.734 Log (avail-$P_2O_5$) + 0.334 Log (extractable-Cu) + 0.186 Log (exchangeable-K) - 0.593 Log (exchangeable-Na) + 0.558 Log (OM). The estimated value in total contents of As was significantly correlated with the measured value in soil ($R^2$=0.84196, p<0.0001). This predictive model for estimating total As contents in paddy soil will be properly applied to the numerous datasets which were surveyed with extractable heavy metal contents based on Soil Environmental Conservation Act before 2010.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.747-751
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• 2008

The effect of additives in the synthesis of biodiesel fuel using supercritical methanol was studied in order to examine the possibility of application of spent vegetable oil as a raw material, which has high contents of water or free fatty acid. The experiments were performed by varying the contents of water, free fatty acid or antioxidants respectively in a batch reactor. The contents of fatty acid methyl ester was analyzed by a gas chromatography. As the water contents increased, the contents of fatty acid methyl ester decreased, however, the decrease was very little compared with the alkaline and acid catalyst. The effect of the contents of free fatty acid, vitamin E, and ${\beta}$-carotene was negligible.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1080-1084
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• 2011

Predictive model for estimating total contents of cadmium (Cd) and lead (Pb) was developed by stepwise multiple-regression analysis using chemical properties and extractable contents of metal in paddy soil adjacent to abandoned mines in 2009 and 2010. Soil properties, e.g. pH, electrical conductivity (EC), organic matter (OM), available phosphorus ($P_2O_5$), and exchangeable cations (i.e. Ca, Na, K, Mg) were measured. Total contents of Cd and Pb as well as extractable contents of metals were analyzed by ICP-OES. Results showed that the total and extractable contents were estimated to be 3.55 and $0.27mg\;kg^{-1}$ in Cd and 83.38 and $24.32mg\;kg^{-1}$ in Pb on the average. From stepwise analysis, it was found that the contents of extractable Cd, Zn, Cu, as well as exchangeable Na were significantly influenced on estimation of the total contents of Cd in soil. Moreover, it also showed that the contents of extractable Pb, Zn, and Cu significantly affected estimation of the total contents of Pb in soil. More significant relationship between estimated and measured value in total contents of Pb was observed than those of Cd ($R^2$=0.87, p<0.0001). This demonstrates that extractable contents of metal are influenced more on estimation of total contents of Cd and Pb in soil than soil properties.

• Journal of the Korean Society of Tobacco Science
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• v.25 no.1
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• pp.20-26
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• 2003

To investigate the effects of reduction of leaf processing factories on the uniformity of processed leaf quality, the contents and their C.V.(Coefficient of Variation) of chemical constituents of flue-cured leaf tobacco produced from 1997 to 2001 and processed at various factories were analysed. The average leaf chemical contents of 12 grades for 5 years ranged as follows ; nicotine 2.00∼0.85%. total sugar 10.7∼16.9%, total nitrogen 2.36∼2.78%, crude ash 14.6∼15.6% and chlorine 0.50∼0.75%. The variations of chemical contents among crop years was higher in total sugar content while lower in crude ash content. The C.V. of chemical content in same grade leaves was higher in chlorine content while lower in total nitrogen and crude ash contents, and the ratio of C.V. among processing factories/C.V. in total population was higher in total sugar content while lower in crude ash content. When the leaves were processed at one factory, the deviations of chemical contents reduced considerably. Particularly, the decreasing effect of deviation was higher in total sugar content.

• Journal of the Korean Society of Tobacco Science
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• v.3 no.1
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• pp.66-74
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• 1981

This study was conducted to investigate the interaction between chemical compositions and agronomic characteristics of perique tobacco leaf. At the topping stage, the thickness of leaf was positively correlated with total sugar($\textrm{0.975}^{**}$), reducing sugar($\textrm{0.975}^{**}$), alkaloid($\textrm{0.518}^{*}$) and petroleum ether extract($\textrm{0.801}^{**}$) contents. The length of upper leaf was negatively correlated with its chemical contents. Total sugar contents of the harvested leaf showed a sigmoid pattern of distribution along the leaf stalk positions.

• Journal of Ecology and Environment
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• v.30 no.1
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• pp.39-47
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• 2007

The relationships between the cover of herbaceous species and 15 soil chemical properties (organic carbon contents, total N, available P, exchangeable K, Na, Ca and Mg, HCl-extractable Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in nine poorly controlled waste landfill sites in Korea were examined by correlation analysis and multiple regression equations. Species showed different patterns of correlation between their cover values and soil chemical properties. The cover of Ambrosia artemisiifolia var. elatior, Aster subulatus var. sandwicensis and Erechtites hieracifolia were negatively correlated with the contents of Fe, Mn and Ni within landfill soils. Total cover of all species in quadrats was positively correlated with the contents of Cd and negatively correlated with the contents of Mn and Fe from stepwise regression analysis with 15 soil properties. Canonical correspondence analysis demonstrated that the distribution of native and exotic plants on poorly controlled landfills was significantly influenced by the contents of Na and Ca in soils, respectively.

• Carbon letters
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• v.10 no.3
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• pp.202-207
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• 2009

Pitch-based carbon fiber tows were prepared from naphtha cracking bottom oil by reforming and carbonization. The relationship between exothermic heat and carbon contents of the fiber was investigated by changing the carbonization conditions. The carbon contents and the crystallinities of isotropic pitch-based carbon fibers were 86.8~93.8 wt% and 33.7~40.1%, respectively, which were linearly proportional to the increase of carbonization temperature from 700 to $1000^{\circ}C$. The exothermic heat (temperature increase) of fiber tows was measured in a short time, which was also linearly proportional to the increase of carbon contents due to the increase of crystallinity, even though the crystallinity was low. Therefore, the carbon contents or carbonization degree of fibers can rapidly and indirectly be estimated by measuring the surface temperature increase of fibers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.354-361
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• 1996

Near Infrared Reflectance Spectroscopy(NIRS) is accepted as today's most versatile method for rapid chemical analysis. The technique offers rapid multicomponent analysis. This study was conducted to improve the efficiency of quality analysis in covered barley grain, and to search for the effects of chemical components variation in covered barley grain on NIRS. Among the three groups with different range in the contents, each equation for starch contents increased standard error of prediction(SEP) and increased correlation coefficient from 0.872 to 0.883. According as, $\beta$-glucan and protein contents decreased SEP and increased correlation coefficient by expanded chemical components variation. Effective equation for ash contents analysis was obtained from group 3. Among the covered barley chemical components, starch and ash contents were required to conduct futher studies in term of accuracy and variation of contents. It was concluded that NIRS method would be applicable for the rapid determination of $\beta$-glucan and protein contents in covered barley grains.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.1
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• pp.57-65
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• 1985

This study was conducted to obtain the information for the difference of chemical characteristics in each tobacco growing districts and year. The results obtained were as follows 1. Difference of chemical characteristics in 6 districts: In case of flue-cured tobacco leaves, the produced leaf tobacco from Cheong Ju and Dae Jeon districts showed middle level in nicotine and total sugar contents, on the other hand, low nicotine and high sugar contents tobacco leaves were produced in An Dong and Jin Ju districts and high nicotine and low sugar contents of tobacco leaves in Su Won and Chun Cheon , respectively. In Burley tobacco leaves, the nicotine and total nitrogen contents of Chun Cheon districts product's were lower than those of Dae Jeon , Jeon Ju and Kwang Ju district's one. 2. Comparison of each tobacco produced year : The nicotine contents of five-cured and Burley tobacco leaves were the highest in 1981 and 1979, respectively. Also, as time goes to recent year, nicotine and total nitrogen contents were decreased and total sugar contents somewhat was increased .

• Journal of the Korean Chemical Society
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• v.14 no.3
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• pp.243-256
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• 1970

Halogen contents of the river water of Seoul city and of municipal reservoirs were investigated from June in 1969 to February in 1970. Bromine contents were ranging from 0.006 to 0.048 mg/1 of the reservoirs, 0.021 to 0.048 mg/1 of Han River, 0.051 to 0.540 mg/1 of rivers running through residential areas and 0.083 to 0.920 mg/1 of rivers running through industrial areas. Bromine contents increased as the river water became contaminated. Most of Br/Cl of Han River and the reservoirs were higher than $3.4{\times}10^{-3}$ of sea water. Bromine contents at 17 different places were the largest in November. The contents of chlorine, iodine and COD (chemical oxygen demand) were nearly correlated with that of bromine. Bromine contents of the river waters in Seoul chiefly originated from consumption of domestic and industrial salt.