• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.203-210
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• 2018

Well-Bing Many consumer forms of natural foods that are not chemically processed due to heat are becoming popular. However, it is very difficult to find foods that do not contain chemical food additives in the modern. Also, there are many products that do not have proper marking of ingredients of chemical food additives or are omitted from marking. Based on the annual data on chemical food additive consumption in Korea, this paper will examine the occurrence of cancer, which is emerging by additives, through time series analysis and regression analysis, one of the big data analysis techniques. Of the total population.

• Resources Recycling
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• v.21 no.3
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• pp.28-38
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• 2012

The purpose of this paper is to develop the alkali-activated concrete which uses 100% fly ash as a binder without any cement. The compressive strength of the mortar was examined depending on the chemical change in alkali-activator through SEM and SEM/EDS observations and the XRD analysis. It was found from the test that the higher molar concentration induced the greater effect on the initial strength, and that $Si^{4+}$ and $Al^{3+}$ were eluted relative to the compressive strength of mortar. In addition, it was confirmed that Al and Si were determined to be most influential ingredients on the microstructural development of the mortar, and that the different ingredient of the activator was almost no change in solidity from the XRD analysis.

• Journal of the Korean Institute of Gas
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• v.23 no.4
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• pp.19-27
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• 2019

The consumption of liquefied natural gas (LNG) has increased annually due to the strengthening of international environmental regulations. In order to produce stable and efficient LNG, it is essential to divide the global (overall) operating condition and construct a quick and accurate monitoring system for each operation condition. In this study, multi-mode monitoring system is proposed to the LNG plant fractionation process. First, global normal operation data is divided to local (subdivide) normal operation data using global principal component analysis (PCA) and k-means clustering method. And then, the data to be analyzed were matched with the local normal mode. Finally, it is determined the state of process abnormality through the local PCA. The proposed method is applied to 45 fault case and it proved to be more than 5~10% efficient compared to the global PCA and univariate monitoring.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.305-311
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• 2013

Effects of cultivation methods on quality characteristics, pasting characteristics, chemical components, and antioxidant activities of sweet potatoes (Ipomoea batatas (L.) Lam) were determined. The Brix degree, hunter color value, pasting characteristics, moisture, protein, and mineral contents of the sweet potatoes showed significant differences from cultivation methods. The total polyphenol and flavonoid contents of the methanolic extracts of the sweet potato's pericarp were higher than sweet potato's sarcocarp. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the sweet potato's pericarp on the conventional culture and successful cropped hairy vetch culture was 776.38 and 715.20 mg TE/100 g sample. The 2,2'-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS) radical scavenging activity of the sweet potato's pericarp on the conventional culture and successful cropped hairy vetch culture was 708.03 and 708.58 mg TE/100 g sample. Generally, there was a difference in antioxidant compound content and radical scavenging activity on the methanolic extract of sweet potato with cultivation methods.

• Journal of the Korea Institute of Building Construction
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• v.16 no.6
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• pp.571-578
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• 2016

Recently, review on viability of various industrial by product and natural materials as raw material for concrete has been actively done in aspect of environment-friendly issue and depletion of natural resource. This study conducted fundamental study on the possibility of utilizing mud flat as admixture and filling material for concrete. First, chemical analysis on the viability of mud flat as admixture was done and the researchers compared it with the substance of fly ash and blast furnace slag. According to the result, substance content was proven to be inadequate. In addition, as the replacement rate of mud flat increased, compressive strength and tensile strength decreased. According to the estimated result of chemical substance analysis, possibility of utilizing mud flat as admixture was low. According to the result of experiment done as filling material, 10% ~ 30% replacement rate of mud flat manifested more than 8 Mpa of compressive strength of block which may be utilized for secondary product. However, additional experiment such as making block is required afterward. According to the result of flow experiment, as the replacement rate of mud flat increased, flow value decreased, and through chloride content analysis test, it was proven that mud flat is inappropriate to be applied as steel beam using structure since it has high content of sodium. It may be utilized as products that does not use steel beam such as internal brick.

• Particle and aerosol research
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• v.14 no.4
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• pp.153-169
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• 2018

To identify a variety of organic compounds in the ambient aerosols, the two-dimensional gas chromatography-time of flight mass spectrometry (GCxGC) system (2DGC) has been applied. While 2DGC provides more peaks, the amount of the generated data becomes huge. A two-step approach has been proposed to efficiently interpret the organic aerosol analysis data. The two-dimensional 2DGC data were divided into 6 chemical groups depending on their volatility and polarity. Using these classification standards, all the peaks were subject to both qualitative and quantitative analyses and then classified into 8 classes. The aerosol samples collected in Seoul in summer 2013 and winter 2014 were used as the test case. It was found that some chemical classes such as furanone showed seasonal variation in the high polarity-volatile organic compounds (HP-VOC) group. Also, for some chemical classes, qualitative and quantitative analyses showed different trends. Limitations of the proposed method are discussed.

• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.435-450
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• 2005

The purpose of the study is to analyze the hydrogeochemical characteristics by multivariate statistical method, to interpret the hydrogeochemical processes for the new variables calculated from principal components analysis (PCA), and to infer the groundwater flow and circulation mechanism by applying the geostatistical methods for each element and principal component. Chloride and nitrate are the most influencing components for groundwater quality, and the contents of $NO_3$ increased by the input of agricultural activities show the largest variation. The results of PCA, a multivariate statistical method, show that the first three principal components explain $73.9\%$ of the total variance. PC1 indicates the increase of dissolved ions, PC2 is related with the dissolution of carbonate minerals and nitrate contamination, and PC3 shows the effect of cation exchange process and silicate mineral dissolution. From the results of experimental semivariogram, the components of groundwater are divided into two groups: one group includes electrical conductivity (EC), Cl, Na, and $NO_3$, and the other includes $HCO_3,\;SiO_2,$ Ca, and Sr. The results for spatial distribution of groundwater components showed that EC, Cl, and Na increased with approaching the coastal line and nitrate has close relationship with the presence of agricultural land. These components are also correlated with the topographic features reflecting the groundwater recharge effect. The kriging analysis by using principal components shows that PC 1 has the different spatial distribution of Cl, Na, and EC, possibly due to the influence of pH, Ca, Sr, and $HCO_3$ for PC1. It was considered that the linear anomaly zone of PC2 in western area was caused by the dissolution of carbonate mineral. Consequently, the application of multivariate and geostatistical methods for groundwater in the study area is very useful for determining the quantitative analysis of water quality data and the characteristics of spatial distribution.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.619-624
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• 2007

Species of genus Acanthopanax(Araliaceae) are long-lived trees primarily distributed throughout East Asia. These species are regarded as medically and ecologically important in Korea. A variety of Cheongsong in Korea is one of these cultivated varieties, however this variety is much longer(>100 years) than those of other cultivated groups. The components of variety of Acanthopanax in Cheongsong were analyzed for the first time and were compared to those of all Acanthopanax taxa in Korea. Nineteen components were specific to variety in Cheongsong. The main components of this variety were $\beta$-caryophyllene, hexadecanoic acid and ethyl stearate. Although some components are differ from each other, variety Cheongsong was similar to A. senticosus at phonetic topology with content of the chemicals, In addition, six species of genus Acanthopanax were investigated to compare the major chemical components by GC-MS.

• Journal of Plant Biology
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• v.6 no.3
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• pp.1-5
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• 1963

Determination of the chemical properties in some forest soils and the naked soil developed on granite in the mountains of the vicinity of Seoul, Korea are presented in this study. The soil under the broad leaved forests has a higher nutrient indicated by available nitrogen, nitrate nitrogen, and phosphorus contents, compared with that under the needle leved forests. On the contrary the content of organic matter and base exchange capacity in the needle forest soils is higher than in the broad leaved forest soils. The significant difference between two horizons of each soil appeared only to be in the content of the available phosphorus, and that of the needle and the broad leaved forest soils, and the naked soils was the nitrate nitrogen and organic matter content among the several chemical properties.

• Journal of the Korean Ceramic Society
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• v.41 no.9
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• pp.677-683
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• 2004

Nd:LLM (Nd:LiLa(MoO$_4$)$_2$) single crystals for the laser host material were grown by the Czochralski method. The Nd:LLM grown single crystals cracked easily, and the reasons of cracks are generally related with phase transition, incongruent melting, chemical heterogeneity of composition, geometric thermal structures of imbalance and growth direction. We confirmed that phase transition is not observed by TG-DTA thermal analysis, and the XRD analysis revealed congruent melting in our products. It was confirmed that the volatilization of Li$_2$O composition is the important reason of chemical heterogeneity. The geometric thermal profile of the resistance furnace of our own design was controlled with a crucible height. Also, Nd:LLM crystal affected growth direction, and was the best quality in case of (101) growth direction. The distribution and effective distribution coefficient of Nd$^{3+}$ ion were accomplished by PIXE analysis.s.