• Journal of the Korean Chemical Society
• /
• v.25 no.1
• /
• pp.30-37
• /
• 1981

A simple micro-sampling system is described which facilitates isolation and concentration of complex organic constituents into three fractions of different volatilities. The method involves the headspace trapping of very volatile components from a complex matrix onto a porous polymer, Tenax GC, followed by the solvent elution of the matrix and the subsequent fractions of the eluate into volatile and less-volatile fractions. The headspace and the volatile fractions are then analyzed by high-resolution capillary gas chromatography. The less-volatile fraction is analyzed by high-performance liquid chromatography. Experimental details and the results obtained using tobacco leaves as a complex organic matrix are presented.

• Applied Chemistry for Engineering
• /
• v.22 no.6
• /
• pp.664-671
• /
• 2011

The vacuum residue of petroleum refinery, i.e. asphalt, was modified through a non-catalytic air blowing process to prepare the semi-blown asphalt. Changes in composition, chemical structure, and physical properties of asphalt were examined. The result from the thin layer chromatography showed that the asphaltene content in asphalt was increased by the air blowing on account of the aromatization of aliphatic hydrocarbon and condensation. These changes in molecular structure were also confirmed by $^1H-NMR$, differential scanning calorimetry, and thermogravimetry. Because of the molecular structure changes, the penetration of asphalt was decreased and the softening point and the flash point of asphalt were increased.

• Food Science and Preservation
• /
• v.6 no.4
• /
• pp.469-474
• /
• 1999

The chemical components of Hovenia dulcis leaf and fruit stalk naturally growing in Korea, were determined. Crude protein of leaf and total sugar of fruit stalk was 7.30 and 51.64%, respectively. The major mineral components were K, Ca, Mg, Na and Mn in that order. The content of vitamin C was 4.8 mg% for leaf and 3.8 mg% for fruit stalk and that of free sugar was 1.37% of fructose for leaf and 8.83% of sucrose for fruit stalk. The highest organic acid in leaf and fruit stalk was malic acid and its content was 1,715.21 mg% and 439.18 mg%, respectively. The highest component of total amino acids in leaf and fruit stalk was glutamic acid(497.99mg%) and proline(751.78mg%), respectively. The highest lady acid in leaf and fruit stalk was 43.54% of linolenic acid and 23.15% of palmitic acid, respectively. trans-Geraniol(124.36 ppm) and isobutyric acid(292.67 ppm) were predominant volatile compounds in leaf and fruit stalk, respectively.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.2
• /
• pp.209-214
• /
• 2012

This experiment was carried out to investigate the replaceability of chemical fertilizer by SCB liquid fertilizer (SCB) in pear orchard for 5 years. The effects on the mineral content of leaf, fruit quality, yield and soil chemical properties are as follows: The mineral content of leaf showed no difference between the treatments; two SCB liquid fertilizer treatments based on the N (SCB-N) and K (SCB-K) content, and control (chemical fertilizer application). There were no significant differences in yield, titratable acidity and weight of the fruit although the figure of fruit weight was high in SCB-N treatment. Soluble solids content was higher in the SCB treatments than the control. Soil chemical properties such as the content of soil organic matter, available soil phosphate and exchangeable cation were not different, although soil pH was higher in SCB treatments. In conclusion, it is suggest that the use of chemical fertilizer in pear orchard could be replaced by the application of SCB liquid fertilizer because of the same effect on the growth of pear tree and soil chemical properties.

• Journal of the Mineralogical Society of Korea
• /
• v.17 no.1
• /
• pp.61-73
• /
• 2004

The purposes of this study are to investigate the occurrence, the hydrochemical characteristics and the origin of the $CO_2$-rich springs from the Kangwon Province, and to reanalyze the previous studied results of other researchers. The $CO_2$-rich water samples were collected at 13 locations in the Kangwon Province. The $CO_2$-rich water shows a high $CO_2$ concentration ($P_{CO2}$ 0.787 to 4.78 atm), weak acidic pHs, electrical conductivity values ranging from 422 to 2,280 $\mu$S/cm, and high Fe and F contents. The chemical compositions of $CO_2$-rich water from this study area are classified into three types; $Ca-HCO_3$, Ca(Na)-$HCO_3$, $Na-HCO_3$ types. The chemical data of $CO_2$-rich waters and their host rocks indicate that $Na-HCO_3$ type water are mainly influenced by biotite, K-feldspar granite, and Ca(Na)-HC $O_3$, type water is chiefly influenced by gneiss and carbonate minerals in granite. F and Fe contents of $CO_2$-rich waters are abundant in $Na-HCO_3$, and $Ca-HCO_3$ types, respectively. The results of this study suggest that the chemical composition $CO_2$-rich water is mainly controlled by the mineralogical composition of aquifer host rocks. Oxygen and deuterium isotope data indicate that $CO_2$-rich water is meteoric origin. The $\delta^{13}$C values (-0.3$\textperthousand$ to -6.2$\textperthousand$ PDB) suggest that dissolved carbonates are mainly derived from a deep-seated $CO_2$ and partly from carbonate minerals.

• 한국지구과학회:학술대회논문집
• /
• 2010.04a
• /
• pp.103-103
• /
• 2010

충남 청양군 대치면 광대리 지역에 분포하는 조계리층에서 역과 혼재된 상태로 보존된 목재화석을 정리하던 중에 규화목과 함께 철광물로 충전된 목재화석이 혼합되어 있는 것을 발견하였다. 본 연구는 철화된 상태로 보존된 재목화석의 구성광물과 화학성분 및 성인에 대해 고찰한 것이다. 연구 지역은 선캄브리아기에 속하는 변성암을 기반암으로 하여 이를 부정합으로 덮고 있는 퇴적암층이 분포한다. 퇴적암은 하부로부터 조계리층과 백운사층으로 구분되며, 조계리층 상부의 역암대에서 재목화석이 산출된다. 규화목의 형태로 보존된 화석은 이미 백승덕(2003), Kim et al. (2005)의 분류학적 연구에 의해 Xenoxylon phyllocladoides, Agathoxylon sp.로 밝혀진 바가 있다. 재목화석의 구성광물을 알아보기 위해 보존상태가 좋은 5개의 표본을 골라서 XRF, XRD, 현미경 관찰을 실시하였다. XRF 분석 결과, 재목화석의 화학성분은 $Fe_2O_3$ (평균 83.18 wt.%)가 가장 높았고, $SiO_2$(평균 7.82 wt.%)로 가장 낮았다. XRD 분석 결과, 목재화석은 침철석(Goethite)으로 구성되어 있음이 밝혀졌다. 재목화석의 단면을 잘라 연마하여 현미경으로 관찰한 결과, 세포조직이 보존되어 있기는 하지만 보존 상태가 좋지 않아 분류를 하기에는 어려움이 있다. 더 많은 시료를 채집하여 현미경적인 연구가 필요하다. 침철석은 기반암, 염기성암체, 황화광물, 함철대의 풍화로부터 생성된 철염의 산화와 가수분해에 의해 생성된다. 목재가 퇴적암 속에 묻혀 화석화작용이 진행되는 동안에 같은 지역에서 규화작용과 철화작용이 동시에 진행된 것으로 판단된다.

• Journal of the Korean Chemical Society
• /
• v.55 no.2
• /
• pp.204-207
• /
• 2011

A particle counting system that can also provide sensitive, specific chemical information, while consuming very less power, occupying less space, and being inexpensive has been developed. This system uses a microwave plasma torch (MPT) as the excitation source for atomic emission spectrometry (AES). Emission from a single particle can be detected, and the wavelength at which the emission is observed indicates the elements present in the particle. It is believed that correlating the particle size and emission intensity will allow us to estimate the particle size in addition to abovementioned capabilities of the system. In the long term, this system can be made field-portable, so that it can be used in atmospheric aerosol monitoring applications, which require real-time detection and characterization of particles at low concentrations.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.05a
• /
• pp.121-121
• /
• 2009

구리 전해정련 과정에서 전해액 중의 Arsenic과 같은 불순물 성분이 전기동의 전착에 미치는 영향을 확인하고, 전해액 중의 최대 허용 농도를 도출하고자 하였다. 전해정련 과정에서 분순물 성분이 전기동 전착에 미치는 영향을 주사전자현미경(SEM), X-선 회절(X-ray diffraction) 및 전기화학적 분석을 통해 수행하였다.

• Journal of Korea Foresty Energy
• /
• v.21 no.2
• /
• pp.69-76
• /
• 2002

To collect the basic data for the use of major softwood and hardwood vinegar, the chemical compositions were analized. In softwood vinegar the phenolic compounds derieved from lignin and extractives are vanillin, guaiacol, 3-methylphenol, acetoguaiacone, 1,2-benzenediol, ethylguaiacol, pyrocatechol. The compound derived from carbohydrates is 2-hydroxy-3-methyl-2-cyclopenten-1-one. The isolated compounds are the most in the phenolic fraction, and in the vinegar of Pinus koraiensis. In hardwood vingar 2-methoxyphenol, 2,6-djmethoxyphenol, 1-(4-hydroxy-3-methoxyphenyl) -ethanone, 3-methoxy-4-hydroxybenzylalcohol, 1-(4-hydroxy-3,5-dimethoxy-phenyl)-ethanone are the compounds derived from lignin and extractives. 2-hydroxy-3-methyl-2,4-cyclopen-1-one, methyl-4-t-butyl-2-furoate are the major compounds derived from the decomposition of carbohydrates. Many different kinds of compounds are analized in the neutral, phenolic and acidic fraction of hardwood vinegar The amount and kinds of compounds in hardwood vinegar are more higher than those of softwood than in softwood.

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