Spatial assessment of groundwater quality in the Jangseong region,South Korea     

Mesfin Benti Tolera  Seunghyuk Park  Sun Woo Chang  Il-Moon Chung 《Environmental Earth Sciences》2017,76(15):545

A total of 129 groundwater samples were collected in the Jangseong region of South Korea to characterize and evaluate groundwater quality and its suitability for irrigation and domestic uses. Samples were chemically analyzed for major ions, pH, electrical conductivity, and total dissolved solids following standard methods. The AquaChem 2014.2 model linked with PHREEQC was used for the statistical analysis and characterization of the hydrochemistry of the groundwater. The analysis showed that in all samples Ca–HCO₃ was the leading water type and that the abundance of major cations was in the order Ca > Na > Mg > K, and of anions in the order HCO₃ > Cl > SO₄ > F. According to the correlation analysis, Ca showed strong interdependence with HCO₃, suggesting that these parameters may have originated from common sources. Saturation index calculations indicated that all samples were undersaturated with respect to aragonite, calcite, dolomite, fluorite, gypsum, halite, and siderite, and oversaturated with respect to goethite and hematite. The irrigation suitability analysis revealed that groundwater in the Jangseong area can be used for irrigation without any restrictions based on EC, sodium adsorption ratio, percent sodium, residual sodium carbonate, Kelley ratio, permeability index, and the US Salinity Laboratory diagram analysis. The drinking water suitability analysis made for major parameters by comparison with the WHO guidelines indicates that the groundwater in the area is suitable for drinking except in some samples with high nitrate–N concentrations. The elevated nitrate concentrations in the groundwater are likely an indicator of agricultural pollution.  相似文献   

Evaluation of the applicability of pier local scour formulae using laboratory and field data     

Chang-Wook Park  Yang-Ki Cho 《Marine Georesources & Geotechnology》2017,35(1):1-7

The reliable estimation of the local scour depth at a bridge pier is essential for proper design and maintenance of bridge piers. Most local scour formulae have been developed based on the results of laboratory experiments. The formulae based on laboratory data do not often produce reasonable predictions for field piers because laboratory investigations are apt to oversimplify or ignore many of the complexities of the flow fields around the bridge piers. Validation of the formulae is necessary in order to ascertain which of the formulae are able to provide reasonable estimates of the local scour depth. In this study, six commonly cited formulae based on laboratory data or field data were selected for validation using 180 laboratory data sets gathered from the literature and 446 field data sets collected from four countries. The six formulae validated in this paper are the Colorado State University (CSU), Neill, Froehlich, Breuser, Laursen, and simplified Chinese formulae. Comparisons between the predicted and measured depths were performed using scour from the laboratory and field data. An artificial neural network technique was also applied in order to compare the tendencies between the field and laboratory data sets.  相似文献   

Characterization of alluvium soil using geophysical and sounding methods     

Chung-Hwa Park  Ji-Hwan Byun  Kyung-Sik Won  Hyun-Tae Cho 《Marine Georesources & Geotechnology》2017,35(1):127-135

The alluvial deposits are highly heterogeneous and thus special techniques for investigating the subsurface have been required to obtain high quality data. The objective of this study is to apply two geophysical methods to alluvial deposits: a seismic survey method and the electrical resistivity method. The one-dimensional sounding method known as the standard penetration test is also applied to investigate subsurface properties and to compare these results with those measured by the geophysical methods. In seismic survey method, the seismic impulse source system shotgun is used to strongly propagate the elastic wave through the soil. The nonpolarizable electrode is selected to obtain the most reliable result by reducing the contact resistance. The application test is performed at Nakdong River in the southern part of Korean Peninsula where the area consists of alluvial deposits. The four profiles are selected for conducting the geophysical methods and the ranges of profiles are 115 ～ 205 m with interval distance of 5 m. The six one-dimensional soundings are performed in the intersection of geophysical profiles. Even though the measured results based on the geophysical method and one-dimensional sounding show slight difference, every result is applied to estimate subsurface characterization as the complementary data.  相似文献   

The correlation between bioaccumulation and pattern of stress-related genes expression of black sea bream (<Emphasis Type="Italic">Acanthopagrus schlegeli</Emphasis>) by cadmium exposure     

Yong Kim  Ho-Ra Park  Won-Jun Yeo  Ji-Hye Kim  Kyung-Nam Han 《Ocean Science Journal》2017,52(2):231-242

In order to correlate the expression of detoxifying enzyme genes and Cd accumulation in black sea bream, we analyzed four tissues (brain, gills, liver, and muscle) from black sea breams that were exposed to four different concentrations of Cd (0, 2, 13, and 25 mg/L) for various durations (0, 24, 48, 72, and 96 h). The highest level of Cd was accumulated in the liver, followed by the gills, brain, and muscle. The accumulation of Cd was significantly correlated with the duration of exposure and the concentration in brain, gill, and liver tissue, but not in muscle tissue, and the rate of accumulation increased with Cd concentration. The expression of metallothionein II (MT II) mRNA exhibited a similar pattern as Cd accumulation, especially in that the expression of MT II mRNA decreased in muscle tissue with increases in exposure duration. In contrast, the expression of cytochrome P450 1A (CYP1A) mRNA was highest in the liver, followed by brain, muscle, and gill tissues, and in gills and muscle tissue of Cd-exposed fish, the expression of CYP1A mRNA fell below that of the control fish. Overall, the liver of black sea bream was the most sensitive to Cd exposure, and the expression of MT II mRNA was 200-fold greater than the control fish. These findings indicate that the detoxification mechanisms of black sea bream are influenced by both MT II and CYP1A and that the genes participate in the detoxification of different tissues.  相似文献   

Flora,life form characteristics,and plan for the promotion of biodiversity in South Korea’s Globally Important Agricultural Heritage System,the traditional Gudeuljang irrigated rice terraces in Cheongsando   总被引：1，自引：0，他引：1  

Hong Chul Park  Choong Hyeon Oh 《山地科学学报》2017,14(6):1212-1228

The objectives of this study were to analyze the biodiversity of the Traditional Gudeuljang Irrigated Rice Terraces in Cheongsando, South Korea’s representative GIAHS (Globally Important Agricultural Heritage System) site, with reference to position and land-use features, and to develop a plan to promote agricultural biodiversity in the region. We confirmed approximately 54,000 m² of Gudeuljang paddy fields by an on-site survey. Of the Traditional Gudeuljang Irrigated Rice Terraces confirmed by onsite inspection, our survey showed that approximately 24,000 m² are currently being used as paddy fields, approximately 15,000 m² are being used as dry fields, and approximately 14,000 m² are fallow. In terms of other non-agricultural land use, there was grassland, including graveyards; artificial arboreal land, such as orchards, rivers and wetlands, and man-made facilities, such as roads and residences. We also confirmed that the Traditional Gudeuljang Irrigated Rice Terraces had higher plant species diversity than conventional terraced rice paddies, and there was a difference in life form characteristics between the two types. Although the superficial topsoil structure is the same for the Traditional Gudeuljang Irrigated Rice Terraces (TGIRTs) and conventional terraced rice paddies, it is thought that the differences in the subsurface structure of the TGIRTs contribute greatly to species and habitat diversity. However, the TGIRTs in Cheongsando are facing degeneration, due to damage and reduction in agricultural activity. The main cause is the reduction in the number of farming households due to an aging population in Cheongsando. In order to address this problem, we proposed a management plan, related to fallow paddy fields in South Korea, to initiate voluntary activities in the TGIRTs.  相似文献   

Photometric Survey of Galactic Open Clusters     

M.G. Lee  H.B. Ann  M.Y. Chun  S. L. Kim  Y. B. Jeon  B. G. Park  I. S. Yuk  H.Sung 《天文研究与技术》1999,(Z1)

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Clockwise rotations recorded in Early Cretaceous rocks of South Korea: implications for tectonic affinity between the Korean Peninsula and North China   总被引：12，自引：0，他引：12  

Xixi Zhao  Robert S. Coe  Ki-Hong Chang  Soon-Ok Park  Sheraz K. Omarzai  Rixiang Zhu  Yaoxiu Zhou  Stuart Gilder  & Zhong Zheng 《Geophysical Journal International》1999,139(2):447-463

Recent interest has focused on whether South Korea may have undergone variable tectonic rotations since the Cretaceous. In an effort to contribute to the answer to this question, we have completed a palaeomagnetic reconnaissance study of Early Cretaceous sedimentary and igneous rocks from the Kyongsang basin in southeast Korea. Stepwise thermal demagnetization isolated well-defined characteristic magnetization in all samples. The palaeomagnetic directions reveal patterns of increasing amounts of clockwise (CW) rotation with increasing age for Aptian rock units. Palaeomagnetic declinations indicate clockwise vertical-axis rotations of R = 34.3° ± 6.9° for the early Aptian rock unit, R = 24.9° ± 10.6° for the middle Aptian, and R = −0.9° ± 11.8° for the late Aptian relative to eastern Asia. The new Cretaceous palaeomagnetic data from this study are consistent with the hypothesis that Korea and other major parts of eastern Asia occupied the same relative positions in terms of palaeolatitudes in the Cretaceous. An analysis of and comparison with previously reported palaeomagnetic data corroborates this hypothesis and suggests that much of Korea may have been connected to the North China Block since the early Palaeozoic. A plausible cause of the rotation is the westward subduction of the Kula plate underneath the Asian continent, which is inferred to have occurred during the Cretaceous according to several geological and tectonic analyses.  相似文献   

Towards a New Approach for Absolute and Exterior Orientation     

M. J. Smith  & D. W. G. Park 《The Photogrammetric Record》1999,16(94):617-623

This paper briefly examines the current position in absolute and exterior orientation and highlights some of the limitations of existing techniques. An alternative system for performing absolute orientation and, potentially, exterior orientation is introduced. Some preliminary tests have given encouraging results.  相似文献   

Comments on 'a new Method to Determine the Zero-Plane Displacement'     

Hong-Sheng Zhang  Soon-Ung Park 《Boundary-Layer Meteorology》1999,91(1):135-139

A brief error analysis associated with the use of the new method to determine the zero-plane displacement proposed by De Bruin and Verhoef has been performed. It is shown that use of temperature fluctuation data is more suited to determining the zero-plane displacement data over a heterogeneous surface.  相似文献   

Experimental investigation of Ostwald-ripening rates of forsterite in the haplobasaltic system     

Youngdo Park  Ben Hanson 《Journal of Volcanology and Geothermal Research》1999,90(1-2)

The rate of Ostwald ripening of forsterite is experimentally measured in a haplobasaltic melt (SiO₂–Al₂O₃–CaO–MgO). The goal of the experiments is to determine if the rate of Ostwald ripening is sufficient to affect textural development in crystallizing magmas of a basaltic composition. With preequilibrated charges, experiments were run isothermally so that all textural changes could be ascribed to Ostwald ripening. An increase of crystal size from 3.5 μm to 14 μm (in average) has been observed during 10 days. Glass compositions were identical in all charges, indicating that the observed increase in average crystal size is not the results of chemical disequilibrium but the results of Ostwald ripening. Due to the constraints on experimental duration, the rate-limiting process (i.e., diffusion control or reaction control) could not be determined. Our experimental results, however, demonstrate that the rate of Ostwald ripening in basaltic rocks is sufficient to be of fundamental importance in the development of textures in igneous rocks. These results strongly suggest that Ostwald ripening, as well as nucleation and crystal growth, should be considered in analyses of textures in igneous rocks.  相似文献