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81.
Rare earth elements (REEs) of 91 fine-grained bottom sediment samples from five major rivers in Korea (the Han, Keum, and
Yeongsan) and China (the Changjiang and Huanghe) were studied to investigate their potential as source indicator for Yellow
Sea shelf sediments, this being the first synthetic report on REE trends for bottom sediments of these rivers. The results
show distinct differences in REE contents and their upper continental crust (UCC)-normalized patterns: compared to heavy rare
earth elements (HREEs), light rare earth elements (LREEs) are highly enriched in Korean river sediments, in contrast to Chinese
river sediments that have a characteristic positive Eu anomaly. This phenomenon is observed also in primary source rocks within
the river catchments. This suggests that source rock composition is the primary control on the REE signatures of these river
sediments, due largely to variations in the levels of chlorite and monazite, which are more abundant in Korean bottom river
sediments. Systematic variations in ΣLREE/ΣHREE ratios, and in (La/Yb)–(Gd/Yb)UCC but also (La/Lu)–(La/Y)UCC and (La/Y)–(Gd/Lu)UCC relations have the greatest discriminatory power. These findings are consistent with, but considerably expand on the limited
datasets available to date for suspended sediments. Evidently, the REE fingerprints of these river sediments can serve as
a useful diagnostic tool for tracing the provenance of sediments in the Yellow Sea, and for reconstructing their dispersal
patterns and the circulation system of the modern shelf, as well as the paleoenvironmental record of this and adjoining marginal
seas. 相似文献
82.
Sumi Kanij Rukshana Kim Soo Cheol Howlader Jewel Sharker Md Rajib Choi Kap Seong Choi Sang Ki Park Jong-In Nou Ill-Sup Kho Kang Hee 《Ocean Science Journal》2019,54(3):363-374
Ocean Science Journal - A carbonic anhydrase VII gene, encoding 277 amino acids, was identified in the intestinal tissue of pufferfish (Takifugu rubripes). The translated protein with an 833-bp... 相似文献
83.
An analysis method for transient groundwater flow during slug tests performed in vertical cutoff walls is presented. The analytical solution for evaluating hydraulic conductivity of vertical cutoff walls is derived by applying the method of images to the previously developed analytical solution that is exclusively applicable to an infinite aquifer. Two distinct boundary conditions are considered to account for the configuration of the vertical cutoff wall: the wall‐soil formation interfaces with or without the existence of filter cakes, that is, constant‐head boundary and no‐flux boundary conditions. A series of type curves is constructed from the analytical solution and compared with those of a partially penetrated well within an aquifer. The constant‐head boundary condition provides faster hydraulic head recovery than the aquifer case. On the other hand, the no‐flux boundary condition leads to a delayed hydraulic head recovery. The greater the shape factor and well offset from the center of the cutoff wall, and the smaller the width of the cutoff wall, the greater the effect of the boundary condition observed in the type curves. This result shows the significance of considering proper boundary conditions at the vertical cutoff wall in analyzing slug tests. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
84.
Long-term discharge of turbid water from reservoirs after flood events is a major socioenvironmental problem in many countries, including Korea. This study used a suite of mathematical models to simulate the fate of turbidity flows in the Soyanggang Reservoir in Korea, an important source of drinking water for the Seoul Capital Area, in response to extreme floods based on the Representative Concentration Pathway 4.5 climate scenario. It evaluated the effectiveness of the selective withdrawal facility (SWF), installed recently in the Soyanggang Reservoir to control persistent turbidity. Extreme floods with a maximum daily inflow rate greater than the historical maximum observed in 2006 were projected to occur four times in this century. The fate and transport of turbidity flows were highly influenced by both the thermal stability of the reservoir and the season in which the flood event occurred. Thus, SWF operations should consider the timing of extreme events (i.e., the imminence of the autumn turnover) to mitigate the impact of high turbidity on the water supply and downstream ecosystem. It was found to be ineffective under extreme events if these occurred in two consecutive years. Current reservoir operations, which rely heavily on the SWF, are likely to be inadequate to overcome the negative effects of extreme-turbidity events on reliably providing safe water supplies. Coping with the worst event expected to occur in the future would require additional countermeasures such as bypassing high-turbidity water. 相似文献
85.
In-Hyuk Kwon Hyo-Jong Song Ji-Hyun Ha Hyoung-Wook Chun Jeon-Ho Kang Sihye Lee Sujeong Lim Youngsoon Jo Hyun-Jun Han Hanbyeol Jeong Hui-Nae Kwon Seoleun Shin Tae-Hun Kim 《Asia-Pacific Journal of Atmospheric Sciences》2018,54(1):319-335
This study introduces the operational data assimilation (DA) system at the Korea Institute of Atmospheric Prediction Systems (KIAPS) to the numerical weather prediction community. Its development history and performance are addressed with experimental illustrations and the authors’ previously published studies. Milestones in skill improvements include the initial operational implementation of three-dimensional variational data assimilation (3DVar), the ingestion of additional satellite observations, and changing the DA scheme to a hybrid four-dimensional ensemble-variational DA using forecasts from an ensemble based on the local ensemble transform Kalman filter (LETKF). In the hybrid system, determining the relative contribution of the ensemble-based covariance to the resultant analysis is crucial, particularly for moisture variables including a variety of horizontal scale spectra. Modifications to the humidity control variable, partial rather than full recentering of the ensemble for humidity further improves moisture analysis, and the inclusion of more radiance observations with higher-level peaking channels have significant impacts on stratosphere temperature and wind performance. Recent update of the operational hybrid DA system relative to the previous 3DVar system is described for detailed improvements with interpretation. 相似文献
86.
Chemical weathering was investigated by collecting samples from five selected weathering profiles in a high elevation granitic
environment located in Seoul, Korea. The overall changes of chemistry and mineralogical textures were examined reflecting
weathering degrees of the samples, using polarization microscopy, X-ray diffraction (XRD), electron probe micro analysis (EPMA),
X-ray fluorescence spectroscopy (XRF), and inductively coupled plasma–mass spectroscopy (ICP–MS). The chemical distribution
in the weathering profiles shows that few trace elements are slightly immobile, whereas most major (particularly Ca and Na)
and trace elements are mobile from the beginning of the granite weathering. On the other hand, there were mineralogical changes
initiated from a plagioclase breakdown, which shows a characteristic circular dissolved pattern caused by a preferential leaching
of Ca cation along grain boundaries and zoning. The biotite in that region is also supposed to be sensitive to exterior environmental
condition and may be easily dissolved by acidic percolated water. As a result, it seems that some rock-forming minerals in
the granitic rock located in Seoul are significantly unstable due to the environmental condition of acidic rainfall and steep
slopes, where they are susceptible to be dissolved incongruently leading some elements to be highly depleted. 相似文献
87.
88.
Towards a better understanding of hydrological interactions between the land surface and atmosphere, land surface models are routinely used to simulate hydro-meteorological fluxes. However, there is a lack of observations available for model forcing, to estimate the hydro-meteorological fluxes in East Asia. In this study, Common Land Model (CLM) was used in offline-mode during the summer monsoon period of 2006 in East Asia, with different forcings from Asiaflux, Korea Land Data Assimilation System (KLDAS), and Global Land Data Assimilation System (GLDAS), at point and regional scales, separately. The CLM results were compared with observations from Asiaflux sites. The estimated net radiation showed good agreement, with r =0.99 for the point scale and 0.85 for the regional scale. The estimated sensible and latent heat fluxes using Asiaflux and KLDAS data indicated reasonable agreement, with r = 0.70. The estimated soil moisture and soil temperature showed similar patterns to observations, although the estimated water fluxes using KLDAS showed larger discrepancies than those of Asiaflux because of scale mismatch. The spatial distribution of hydro-meteorological fluxes according to KLDAS for East Asia were compared to the CLM results with GLDAS, and the GLDAS provided online. The spatial distributions of CLM with KLDAS were analogous to CLM with GLDAS, and the standalone GLDAS data. The results indicate that KLDAS is a good potential source of high spatial resolution forcing data. Therefore, the KLDAS is a promising alternative product, capable of compensating for the lack of observations and low resolution grid data for East Asia. 相似文献
89.
90.
Guanie Lim 《Singapore journal of tropical geography》2016,37(2):176-194
This paper examines the Malaysian Chinese firms that have expanded into Vietnam. Based on research and qualitative personal interviews with Malaysian Chinese firms that have invested in Vietnam, the paper unpacks the entry modes that these firms have undertaken. It argues that the Malaysian Chinese firms prefer joint ventures in their Vietnamese businesses to wholly‐owned subsidiaries and personal direct investments. This paper also argues that such investments are often embedded in social and intraethnic ties, which connect Malaysian Chinese firms with Vietnam's ethnic Chinese businessmen. To this end, these firms tend to rely on informal ties and nonmarket institutions in the form of the ethnic Chinese business networks. Nevertheless, the Malaysian Chinese firms are not averse to collaborating with nonethnic Chinese firms that enjoy a good relationship with the Vietnamese state. This observation is especially marked in the property and construction, and finance sectors. 相似文献