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Search Results: 1 - 10 of 565260 matches for " S. -J. Kim "
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Organic carbon efflux from a deciduous forest catchment in Korea
S. J. Kim, J. Kim,K. Kim
Biogeosciences (BG) & Discussions (BGD) , 2010,
Abstract: Soil infiltration and surface discharge of precipitation are critical processes that affect the efflux of Dissolved Organic Carbon (DOC) and Particulate Organic Carbon (POC) in forested catchments. Concentrations of DOC and POC can be very high in the soil surface in most forest ecosystems and their efflux may not be negligible particularly under the monsoon climate. In East Asia, however, there are little data available to evaluate the role of such processes in forest carbon budget. In this paper, we address two basic questions: (1) how does stream discharge respond to storm events in a forest catchment? and (2) how much DOC and POC are exported from the catchment particularly during the summer monsoon period? To answer these questions, we collected hydrological data (e.g., precipitation, soil moisture, runoff discharge, groundwater level) and conducted hydrochemical analyses (including DOC, POC, and six tracers) in a deciduous forest catchment in Gwangneung National Arboretum in west-central Korea. Based on the end-member mixing analysis of the six storm events during the summer monsoon in 2005, the surface discharge was estimated as 30 to 80% of the total runoff discharge. The stream discharge responded to precipitation within 12 h during these storm events. The annual efflux of DOC and POC from the catchment was estimated as 0.04 and 0.05 t C ha 1 yr 1, respectively. Approximately 70% of the annual organic carbon efflux occurred during the summer monsoon period. Overall, the annual efflux of organic carbon was estimated to be about 10% of the Net Ecosystem carbon Exchange (NEE) obtained by eddy covariance measurement at the same site. Considering the current trends of increasing intensity and amount of summer rainfall and the large interannual variability in NEE, ignoring the organic carbon efflux from forest catchments would result in an inaccurate estimation of the carbon sink strength of forest ecosystems in the monsoon East Asia.
Organic carbon sequestration and discharge from a deciduous forest catchment in Korea
S. J. Kim,J. Kim,K. Kim
Biogeosciences Discussions , 2009,
Abstract: Soil infiltration and surface discharge of precipitation are critical processes that affect the sequestration and discharge of dissolved organic carbon (DOC) and particulate organic carbon (POC) in forested catchments. Both DOC and POC are highly concentrated in the soil surface in most forest ecosystems and their discharge may not be negligible particularly under the monsoon climate. In East Asia, however, there are little data available to evaluate the role of such processes in forest carbon budget. In this paper, we address two basic questions: 1) how does stream discharge respond to storm events in a forest catchment? and 2) how much DOC and POC are discharged from the catchment particularly during the summer monsoon period? To answer these questions, we collected hydrological data (e.g., precipitation, soil moisture, runoff discharge, groundwater level) and conducted hydrochemical analyses (including DOC, POC, and six tracers) for a deciduous forest catchment in Gwangneung National Arboretum in west-central Korea. Based on the end-member mixing analysis of the six storm events during the summer monsoon in 2005, the surface discharge was estimated as 30 to 80% of the total runoff discharge. The stream discharge responded to precipitation within 12 h during these storm events. The annual discharge of DOC and POC from the catchment was estimated as 0.04 and 0.05 t C ha 1 yr 1, respectively. Approximately 70% of the annual organic carbon efflux occurred during the summer monsoon period. Overall, the annual discharge of organic carbon was estimated to be 4 to 14% of the net ecosystem carbon exchange (NEE) obtained by eddy covariance technique at the same site. Considering the current trends of increasing intensity and amount of summer rainfall and the large interannual variability in NEE, ignoring the organic carbon discharge from forest ecosystems would result in an overestimation (underestimation) of the strength of forests as a carbon sink (source) in the monsoon East Asia.
Evaluation of Accuracy and Precision of IRMS by Using Standard Materials and Applications  [PDF]
J. Y. Hwang, B. K. Kim, M. S. Kim, J. W. Choi, T. S. Kim, W. S. Lee
Journal of Agricultural Chemistry and Environment (JACEN) , 2016, DOI: 10.4236/jacen.2016.54022
Abstract: The isotope ratio mass spectrometer (IRMS) is an instrument that measures both of the elemental contents and isotope ratios of hydrogen, oxygen, carbon, nitrogen and sulfur in environmental samples at the same time. In this study, we want to try to get two main goals; first, to make up for setting the analytical conditions such as accuracy and precision, second, to apply for comparing of the carbon and nitrogen isotope ratio of sediments in the abandoned mine located in middle province of Korea. For the first goal, a recently introduced IRMS was used to analyze CRM (certified reference materials), which helped to make up the analytical conditions of carbon and nitrogen isotope ratios. So, the accuracy and precision of isotope ratios and elemental contents were also assessed simultaneously, and also the results were very satisfactory. The analytical results of carbon reference materials (EMA-P2) showed an accuracy of -2.801 × 10‰ ± 0.01‰ (2σ) and a precision of 0.009‰ in the mass range from 0.008 μg - 0.162 μg. For nitrogen reference materials (EMA-P2), an accuracy of -1.632‰ ± 0.72‰ (2σ) was obtained in the mass range from 0.082 - 0.162 mg. These values of accuracy and precision are higher than those reported by other studies. For the second goal, carbon and nitrogen isotopes in river sediment near abandoned mines were analyzed based on the established analytical conditions. The result suggested that carbon isotope ratios ranged from -22.5‰ - -7.5‰ and nitrogen isotope ratios from -1.9‰ - 7.9‰. By comparing the isotope ratios and sampling sites of sediment, we know that the nitrogen isotope values in samples of entrance area of mine are greater than those of the farm house area, which is indicating the effects of organic materials. So, we could guess that the newly accumulated organic materials were much more in the farm house area than mine entrance area. And a result of this study, the accuracy and precision tests of IRMS using certified reference materials were very satisfactory and optimum analytical conditions were established well. And also, it was found that the applications of isotopic analysis for environmental samples by using the IRMS could be very useful for the studies on tracing pollution sources.
Analysis of food components of freeze-dried Alaska Pollack (Hwangtae)
J-S Kim, KS Kim, M-J Kim
African Journal of Biotechnology , 2010,
Abstract: Physiochemical properties of freeze-dried Alaska Pollack (Hwangtae) were investigated. The moisture, crude ash and crude fat content of Hwangtae were 12.53, 5.91 and 0.94%, respectively. Contents of saccharides were found to be 3.69 mg/100 g in dried weight of glucose and 5.71 mg/100 g in dried weight of sucrose. Minerals in 100 g dry weight of Hwangtae include phosphorus (806.5 mg), calcium (612.7 mg), potassium (442.2 mg), sodium (283.5 mg), magnesium (89.9 mg), zinc (1.9 mg), iron (0.8 mg), manganese (0.3 mg) and aluminum (0.2 mg), respectively. Glutamic acid and aspartic acid were the major amino acids, containing 925.4 and 644.7 mol/g in dried weight, respectively. Fatty acids in Hwangtae were composed of monounsaturated fatty acids, polyunsaturated fatty acids and saturated fatty acids, containing 16.3, 41.2 and 42.5%, respectively. Our results suggested that this Hwangtae, a freeze-dried fish, can be used as a good nutrition source for human health.
Weierstrass semigroups on double covers of genus four curve
S. J. Kim,J. Komeda
Mathematics , 2013,
Abstract: Let C be a complete non-singular irreducible curve of genus 4 over an algebraically closed field of characteristic 0. We determine all possible Weierstrass semigroups of ramification points on double covers of C which have genus greater than 11. Moreover, we construct double covers with ramification points whose Weierstrass semigroups are the possible ones.
Disassortativity of random critical branching trees
J. S. Kim,B. Kahng,D. Kim
Physics , 2009, DOI: 10.1103/PhysRevE.79.067103
Abstract: Random critical branching trees (CBTs) are generated by the multiplicative branching process, where the branching number is determined stochastically, independent of the degree of their ancestor. Here we show analytically that despite this stochastic independence, there exists the degree-degree correlation (DDC) in the CBT and it is disassortative. Moreover, the skeletons of fractal networks, the maximum spanning trees formed by the edge betweenness centrality, behave similarly to the CBT in the DDC. This analytic solution and observation support the argument that the fractal scaling in complex networks originates from the disassortativity in the DDC.
Hierarchical Quark Mixing and Bimaximal Lepton Mixing on the Same Footing
C. S. Kim,J. D. Kim
Physics , 1999, DOI: 10.1103/PhysRevD.61.057302
Abstract: We show that not only the hierarchical quark CKM mixing matrix but also the "bimaximal" lepton flavor mixing matrix can be derived from the same mass matrix ansatz based on the broken permutation symmetry, by assuming the hierarchy of neutrino masses to be $m_1\simeq m_2 <
Identities Involving -Bernoulli and -Euler Numbers
D. S. Kim,T. Kim,J. Choi,Y. H. Kim
Abstract and Applied Analysis , 2012, DOI: 10.1155/2012/674210
Abstract: We give some identities on the q-Bernoulli and q-Euler numbers by using p-adic integral equations on ?.
A Note on Some Identities of Frobenius-Euler Numbers and Polynomials
J. Choi,D. S. Kim,T. Kim,Y. H. Kim
International Journal of Mathematics and Mathematical Sciences , 2012, DOI: 10.1155/2012/861797
Abstract: The purpose of this paper is to give some identities on the Frobenius-Euler numbers and polynomials by using the fermionic -adic -integral equation on ?.
Some Identities on Bernoulli and Euler Numbers
D. S. Kim,T. Kim,J. Choi,Y. H. Kim
Discrete Dynamics in Nature and Society , 2012, DOI: 10.1155/2012/486158
Abstract: Recently, Kim introduced the fermionic p-adic integral on ?. By using the equations of the fermionic and bosonic p-adic integral on ?, we give some interesting identities on Bernoulli and Euler numbers.
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