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11.
LI Shan CHUNG Sunlin Simon A. WILDE WANG Tao XIAO Wenjiao GUO Qianqian 《《地质学报》英文版》2016,90(5):1907-1908
正Objective The modern Earth is characterized by two types of orogens:collisional orogen and accretionary orogen.It is widely accepted that the Central Asian Orogenic Belt(CAOB)is made up of widespread multiple ancient archipelagos.It has been recognized as a non-collisional orogen,contrasting with the archetypical AlpineHimalayan-type collisional orogens.Although the CAOB is 相似文献
12.
Provenance of Cored Sediments from Active Margin off Southwestern Taiwan Deduced from Geochemical Constraints 总被引：1，自引：0，他引：1
HUANG Shaowei CHEN Juchin LO Chienying LEE Yungtan JIANG Weiteh WANG Yunshuen CHUNG Sanhsiung 《《地质学报》英文版》2014,88(1):128-141
The cored sediments sampled by R/V Marion Dufrense in the active margin off southwestern Taiwan on the east side of the Manila Trench are mostly muds consisting mainly of quartz, feldspar, illite, chlorite ＋ kaolinite with a trace amount of montmorillonite. The cored sediments have higher Fe, Ti, Cr, Cs, Li, Ni, and V but lower Ca, Na, Mn, Hf, Nb, Sr, Ta, U and Zr contents when compared with the upper continental crust（UCC, Taylor and McLennan, 1985）. The Eu/Eu＊ ratios of the sediments averaging 0.69 indicate that the recycling effect on the Eu anomaly may be minor and the contribution of mafic source rock was unimportant, which can also be depicted in the La-Th-Sc plot（Cullers, 1994） showing a ＂mixed origin＂ close to the felsic end member. The chemistry of the cored sediment can be explained by a mixing model designed by Ho and Chen（1996） with four end members i.e., greywacke, shale, quartzite and limestone, which are widely distributed in the Cenozoic formations of southern Taiwan with greywacke as the dominant contributor followed by shale. 相似文献
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14.
S. G. CHUNG K. NAGENDRA PRASAD T. S. NAGARAJ J. G. CHUNG K. Y. JO 《Marine Georesources & Geotechnology》2013,31(1-2):1-20
It Naturally cemented soft clays have components of strength and stiffness, which cannot be accounted for by classical soil mechanics (Leroueil and Vaughan 1990). This stems from the influence of structure caused by cementation due to environmental factors. It is necessary to evaluate the cementation bond strength at preyield and postyield stress levels of loading, to understand comprehensively the observed response from micromechanic considerations. This helps to better understand and evolve approaches to model the constitutive behavior in a consistent manner, according to the physical phenomenon of formation of cementation as an additional component to what is otherwise normally regarded as frictional behavior arising only from particulate nature of clays. Comparing the behavior of deep deposits of Pusan soft clays under stress with corresponding response of the same clay in its remolded state, it has been possible to take into account particulate and nonparticulate responses. The evolution of cementation bonding is modeled for different Pusan clays with the yield stress in oedometer compression as a normalizing parameter for obtaining the generalized relationship of cementation bonding with increase in stress. The already established model for determining the remolded behavior is appropriately modified to assess the behavior influenced by cementation. The model proposed consists of parameters, which are determined in routine investigations. 相似文献
15.
Sang-Ho Lee Moon-Jin Kim Chang-Soo Kim Byoung-Ju Choi Hong-Bae Moon 《Ocean Science Journal》2017,52(3):307-327
To examine the surface circulation and vertical structure of currents in the region of the Keum River (KR) plume, we analyzed the subinertial surface currents obtained by high frequency radar and the vertical profiles of currents measured at a station (M1) located 10 km distance from the estuary mouth for one month in late spring 2008. Monthly-mean surface circulation is composed of the westward flow from the estuary mouth and the northward flow in the offshore. These surface mean currents are a gradient (geostrophic) current around the monthly-mean plume bulge. Dominant variabilities of the surface currents, winds, and KR-outflow are decomposed by the Empirical Orthogonal Functions (EOF). The first current EOF mode, explaining 39% of total variation, is primarily related to the first wind EOF mode varying along the coast and the second current mode, explaining 33% of total variation, is mainly related to the first KR-outflow EOF mode varying along the mean KR-outflow direction. Meanwhile, vertical profile of the monthly-mean current at M1 shows a two-layer structure of the current flowing offshore (onshore) in the upper (lower) layer because the water column is divided by a pycnocline at 7-9 m depths below the plume water. This two layer structure is a background persisting current structure, at least in spring, maintained by the geostrophic balance induced by the sea level slope and density gradient along the line normal to the westward mean surface current direction due to monthly-mean plume bulge off the KR estuary. EOF analysis of vertical current profiles reveals that the first mode, explaining 43% of total variation, represents the two-layer structure of the current variability. The upper-layer current varies along a line normal to the mainland coastline and the low-layer one varies approximately along a line parallel to the coastline, with direction difference of about 115° between the upper-and low-layer. From the correlation analysis it is found that 60% of the first mode variation is influenced by the first mode of KR-outflow and 36% by the first mode of wind. Any forcing modes of KR-outflow and wind influencing the other current vertical modes could not be found in the present study. 相似文献
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Ki-Hoon Song Ki-Young Choi Chang-Joon Kim Young-Il Kim Chang-Soo Chung 《Ocean Science Journal》2015,50(4):721-740
As with many countries, the Korea government has made a variety of efforts to meet the precautionary principle under the London Convention and Protocol acceded in 1994 and 2009. However, new strategies for the suitable marine dumping of waste materials have since been developed. In this study, the distribution and contamination of heavy metals including Al, Fe, Mn, Li, Co, Cr, Ni, Cu, Zn, As, Cd, Pb and Hg in bottom sediments were analyzed and compared to various criteria in order to evaluate the effectiveness of the management of the East Sea-Jung (ES-Jung) dumping site by the Korea government. The results indicate that the average metal concentrations were significantly lower than Effects Range Low (ERL) values, and generally similar to or lower than the Threshold Effect Levels (TEL) from the Sediment Quality Guidelinces (SQGs). According to analyses of various metal contamination indexes (Enrichment Factor: EF, Pollution Load Index: PLI and the Index of Geoaccumulation: Igeo), most areas were found to be uncontaminated by heavy metals with the exception of several moderately contaminated stations (ESJ 33, 54, 64 and ESJR 20). Heavy metal concentrations in areas grouped as G1, G2, DMDA, N-Ref and S-Ref which showed similar characteristics between 2007-2013 and 2014, were compared. Unexpectedly, most concentrations in the northern reference area (N-Ref) were much higher than those in the actual dumping areas (G1 and G2), may be due to the influences from nearby cities to the west of the ES-Jung site, rather than from the dumping site itself. Additionally, heavy metal concentrations in the dredged material dumping area (DMDA) were found to be low although they have slightly increased over time and those in the southern reference area (S-Ref) were found to have gradually decreased with year. The concentrations of most metals in the East Sea-Jung dumping site were similar to or less than those in the Earth’s crust and approximately the same as those in continental sediments. As a result, this site can be considered as uncontaminated or slightly contaminated. This implies that the efforts made by the Korea government to manage and govern the dumping site through various policies, including ‘the focal point system’, ‘the responsibility zones system’ and ‘the principle of pollution causing party liability’, have been successful. 相似文献
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The optimum parameters of tuned mass dampers (TMD) that result in considerable reduction in the response of structures to seismic loading are presented. The criterion used to obtain the optimum parameters is to select, for a given mass ratio, the frequency (tuning) and damping ratios that would result in equal and large modal damping in the first two modes of vibration. The parameters are used to compute the response of several single and multi-degree-of-freedom structures with TMDs to different earthquake excitations. The results indicate that the use of the proposed parameters reduces the displacement and acceleration responses significantly. The method can also be used in vibration control of tall buildings using the so-called ‘mega-substructure configuration’, where substructures serve as vibration absorbers for the main structure. It is shown that by selecting the optimum TMD parameters as proposed in this paper, significant reduction in the response of tall buildings can be achieved. © 1997 John Wiley & Sons, Ltd. 相似文献
18.
Gi-Hoon Hong Young-Ill Kim Mark Baskaran Suk-Hyun Kim Chang-Soo Chung 《Journal of Oceanography》2008,64(2):277-292
The distribution of the natural radionuclide 210Po in the water column along a horizontal transect of the continental shelf, slope and deep basin regions of the East Sea
(Sea of Japan), a marginal sea of the Northwest Pacific Ocean, was investigated, and its behavior is described here. The settling
fluxes of particulate 210Po in the deep basin along with 210Pb, 234Th and biogenic matter were also determined. 210Po inventories in the water column were observed to decrease from winter to summer in all stations, probably due to increased
influx of 210Po-poor Kuroshio Water of the Northwest Pacific Ocean during summer. Vertical profiles of dissolved and particulate 210Po along with the settling fluxes of particulate 210Po in the deep basin station have enabled us to evaluate temporal variations and residence times of 210Po. In the slope and basin, activities of dissolved 210Po generally decreased from the surface to the bottom water, with maximum activity just below the subsurface chlorophyll a maximum at 50–75 m depth in spring and summer. These subsurface peaks of dissolved 210Po activity were attributed to the release of 210Po from the decomposition of 210Po-laden biogenic particulate organic matter. In the deep basin, despite the decrease in total mass flux, the sinking flux
of particulate 210Po was higher in the deeper trap (2000 m) than in the shallower one (1000 m), probably due to scavenging of dissolved 210Po from the water column during particle descent and/or break-down of 210Po-depleted particulate matter between 1,000 m and 2,000 m depths. In general, the ratios of the particulate phase to the
dissolved phase of 210Po (Kd) increased with depth in the slope and basin stations. 210Po removal from the water column appears to depend on the primary productivity in the upper waters. There is an inverse relationship
between Kd and suspended particulate matter (SPM) concentration in the water column. From the 210Po activity/chlorophyll a concentration ratios, it appears that sinking particles arriving at 1000 m depth were similar to those in the surface waters. 相似文献
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Chang-Guk Sun Chang-Soo Cho Minkyung Son Jin Soo Shin 《Pure and Applied Geophysics》2013,170(3):271-281
Shear wave velocity (V S) can be obtained using seismic tests, and is viewed as a fundamental geotechnical characteristic for seismic design and seismic performance evaluation in the field of earthquake engineering. To apply conventional geotechnical site investigation techniques to geotechnical earthquake engineering, standard penetration tests (SPT) and piezocone penetration tests (CPTu) were undertaken together with a variety of borehole seismic tests for a range of sites in Korea. Statistical modeling of the in-situ testing data identified correlations between V S and geotechnical in-situ penetration data, such as blow counts (N value) from SPT and CPTu data including tip resistance (q t), sleeve friction (f s), and pore pressure ratio (B q). Despite the difference in strain levels between conventional geotechnical penetration tests and borehole seismic tests, it is shown that the suggested correlations in this study is applicable to the preliminary determination of V S for soil deposits. 相似文献
20.
Ching‐Hua LO Kieren T. HOWARD Sun‐Lin CHUNG Sebastien Meffre 《Meteoritics & planetary science》2002,37(11):1555-1562
Abstract— Three samples of Darwin Glass, an impact glass found in Tasmania, Australia at the edge of the Australasian tektite strewn field were dated using the 40Ar/39Ar single‐grain laser fusion technique, yielding isochron ages of 796–815 ka with an overall weighted mean of 816 ± 7 ka. These data are statistically indistinguishable from those recently reported for the Australasian tektites from Southeast Asia and Australia (761–816 ka; with a mean weighted age of 803 ± 3 ka). However, considering the compositional and textural differences and the disparity from the presumed impact crater area for Australasian tektites, Darwin Glass is more likely to have resulted from a distinct impact during the same period of time. 相似文献