中国东北地区中生代火山岩的大地构造意义   总被引：101，自引：2，他引：99       下载免费PDF全文

林强  元钟宽 《地质科学》1998,33(2):129-139

中国东北地区中生代火山岩可划分为西部大兴安岭环状火山岩带、南部火山岩带和东部火山岩带,它们是古亚洲洋构造域向太平洋构造域转换时期不同构造环境的产物。西部大兴安岭环状火山岩带的形成与古亚洲洋闭合过程中壳幔相互作用引起的深部热地幔柱的上升有关,南部火山岩带与构造域转换时期走滑拉伸构造有关,而东部火山岩带则是太平洋板块斜向俯冲作用的产物。  相似文献   

Reproductive pattern of the epifaunal amphipodPontogeneia rostrata (Crustacea) on dolsando sandy shore in Korea     

Ok Hwan Yu  Seung Jin Jeong  Hae-Lip Suh 《Ocean Science Journal》2008,43(3):127-133

Reproductive patterns of an epifaunal amphipod,Pontogeneia rostrata, were studied on Dolsando sandy shore in Korea. The life history pattern was iteroparous, with recruitment mainly occurring from winter to spring. The sex ratio was male-biased, especially during breeding periods. The mean body length of females was significantly larger than that of males. Brood size and egg volume were positively related to the body length of ovigerous females. There was no significant difference in brood size between successive breeding periods, but egg volumes were significantly higher in early winter (December) than in late spring breeding (May and June), increasing the probability of survival to hatching. These traits contribute to more reproductive potential in early winter than in late spring breeding. The mean brood size of epifaunalP. rostrata was larger but the mean egg volume smaller than that of infaunal amphipods in this sampling area. We suggest that reproductive effort for epifaunal species may be proportionally greater than for infaunal species in risky environments.  相似文献   

Application of a regionalized Clark IUH model with limited hydrologic data availability     

Kee‐Won Seong  James E. Ball  Yong‐Hak Lee 《水文研究》2008,22(18):3651-3660

To aid prediction of the flow hydrograph in a basin with limited data, a practical approach to determining a regionalized Clark instantaneous unit hydrograph (IUH) model is presented. The proposed model is described in terms of the synthetic time–area concentration curve, the concentration time, and a special regional similarity value that is valid in the whole basin. The latter was estimated from a Monte Carlo testing procedure based on the normal probability distribution of transformed regional similarity values composed of the time of concentration and the storage coefficient in gauged basins. The time–area concentration curve and the concentration time were calculated from a rational equation as in conventional methods. The method of transformation adopted was the Box–Cox power transformation, which is known to make non‐normal values resemble normal data. By introducing the regional similarity value into a Clark IUH, a statistically best estimate of IUH for given data conditions and its quantified degree of uncertainty were realized. The Wi River basin in Korea was used to test the applicability of the regionalized Clark IUH. The performance of the suggested methodology was evaluated by assuming an ungauged sub‐basin at the site. The results showed that the IUH model developed in this work was an effective tool, predicting a reliable hydrograph within the study area even though only limited data were available. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Crown fuel characteristics and carbon emission from Japanese red pine stands burned by crown fire in Mt. Palgong, South Korea     

Byungdoo LEE  Myoung Soo WON  Yohan LEE  Myung Bo LEE 《山地科学学报》2012,9(5):656-664

Carbon emissions from forest fires are considered an important factor of ecosystem carbon balance and global climate change. Carbon emissions from Japanese red pine stands (Pinus densiflora S. et Z.) burned by crown fire were estimated at Mt. Palgong in Daegu Metropolitan City, and crown fuel characteristics, including crown bulk density, crown base height, and fuel moisture content of Japanese red pine, were analyzed. Total biomass combusted was calculated by subtracting the biomass of burned stands from that of unburned stands exhibiting similar stand structures and site environments. Ten trees in the unburned area and five trees in the burned area were cut by using direct harvesting techniques to estimate crown layer biomass. All biomass sampled was oven-dried and weighed. The dry weight ratios of stems, branches, and needles were 70%, 21%, and 9%, respectively. The available fuel load susceptible to combustion during the crown fire spread was equivalent to 55% of the crown layer biomass. The crown bulk density was 0.24 kg/ m 3 on average. The estimated amount of CO 2 was 23,454 kg CO 2 /ha for the crown layer. These results will be useful for calculating the amount of CO 2 emitted from forest fires and for developing a forest carbon model in P. densiflora forests.  相似文献   

Persistent organochlorine pollutants in Korean offshore waters: Squid (Todarodes pacificus) as a biomonitor     

Jong Ho Won  Sang Hee Hong  Won Joon Shim  Gi Beum Kim 《Marine pollution bulletin》2009,58(8):1238-1244

Persistent organochlorine pollutants (POPs) such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), and hexachlorocyclohexanes (HCHs) were determined in Japanese common squid collected from the offshore waters of Korea. Liver accumulated higher levels of contaminants than mantle. The sums of DDTs, PCBs, CHLs and HCHs in liver were in the ranges of 164-4430 ng g⁻¹, 95-1030 ng g⁻¹, 15-121 ng g⁻¹, and 13-98 ng g⁻¹ on a lipid weight basis, respectively. Among the POPs, DDTs showed distinct regional difference in concentration levels and composition between the western and eastern offshore of Korea. One of the highest concentrations of DDTs so far recorded in the western offshore of Korea, that is Yellow Sea. This implies ongoing fresh input of technical DDT to this regional sea. HCHs were relatively high in the Yellow Sea as well, with an enhanced signal of γ-HCH indicating recent input of lindane. In contrast, CHLs showed higher level in the eastern offshore of Korea, that is East Sea, but PCBs showed an even distribution in both regions. Squid could be a useful bio-indicator for monitoring offshore water contamination by POPs.  相似文献   

Effects of <Emphasis Type="Italic">Urechis unicinctus</Emphasis> juveniles on chemical characteristics of organically contaminated coastal sediment     

Kyoung Ho Kang  Zhifeng Zhang  Jae Min Kim  Seung Chun Seon  Mingyu Shao 《中国海洋大学学报(英文版)》2010,9(1):48-52

Biological activities of marine benthos such as burrowing and feeding may change sediment characteristics. We conducted three experiments to examine the potential of using juveniles of a spoon worm Urechis unicinctus to improve the quality of organically contaminated coastal sediment. Sediment samples were collected from a site that was heavily contaminated with organic matter (Seonso) and two sites that were clean (Myo-do, Dolsan-do). Urechis juveniles, obtained by artificial fertilization and cultured in the laboratory, were introduced to the sediment (weight 3 kg, depth 10 cm) at a density of 500 individuals per aquarium (length 50 cm, width 35 cm, height 30 cm) (Experiment 1), or at densities ranging from 100 to 900 individuals per beaker (Experiment 2). To examine how sediment contamination can be modified by the effects of Urechis, 500 individuals (per aquarium) were exposed to the Seonso contaminated sediment that had been mixed with 0–100% clean sand (Experiment 3). Each experiment lasted two months and sediment samples were collected every 15 d to determine the several indexes of sediment quality, which included acid volatile sulfide (AVS), chemical oxygen demand (COD) and total ignition loss (TIL). In Experiment 1, the existence of Urechis did not result in significant changes in quality indexes in the sediments collected from Myo-do, Dolsan-do. However, AVS, COD and TIL of the Seonso sediment all decreased significantly after co-incubation with Urechis juveniles for 30 to 45 d. Experiment 2 showed that a density of at least 300 juveniles per beaker was necessary to significantly reduce all three quality indexes, and the magnitude of reduction was positively correlated with juvenile density. Experiment 3 revealed that Urechis juveniles were effective in reducing the AVS, COD and TIL of the Seonso sediment that had been mixed with 60%, 80%, and 80% of clean sand, respectively. The results of the present study therefore indicated that juveniles of this spoon worm have the potential to be used to improve the quality of organically contaminated sediment in coastal waters.  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   

Effects of temperature and salinity on the asexual reproduction of <Emphasis Type="Italic">Nemopilema nomurai</Emphasis> (Scyphozoa: Rhizostomeae)     

Hye Eun Lee  Chang Hoon Han  ByeongHo Kim  Won Duk Yoon 《Ocean Science Journal》2017,52(4):573-579

Asexual reproduction of polyps of Nemopilema nomurai, of which massive blooms have occurred in Korean waters every summer since 2003, were tested under 20 combinations of temperature (10, 15, 20, and 25°C) and salinity (12, 17, 22, 27, and 32 psu). Production of podocysts increased with increasing temperature (20 and 25°C), while strobilaton and ephyral liberation occurred at low temperatures (10 and 15°C). Temperature also affected the initiation of ephyral liberation (approximately 25 days at 15°C, and 50 days at 10 and 20°C, respectively). The number of podocysts was only significantly different between 27 and 32 psu, and salinity had no significant effect on the excystment of podocysts, ephyral liberlation, showing N. nomurai is euryhaline. These results demonstrated that temperature is an important factor on both the podocysts production and ephyrae liberation, possibly explaining early spring liberation of ephyrae and continuous introduction of medusae into Korean coastal waters through summer to fall.  相似文献   

Seasonal and spatial distribution of nonylphenol and IBP in Saemangeum Bay, Korea     

Li D  Dong M  Shim WJ  Hong SH  Oh JR  Yim UH  Jeung JH  Kanan N  Kim ES  Cho SR 《Marine pollution bulletin》2005,51(8-12):966-974

In order to investigate spatial and temporal distribution of organic pollutants in the Saemangeum Bay, organophosphorus pesticides (10), alkylphenols (8), chlorophenols (2), bisphenol A were analyzed from the surface seawater taken in 2002–2003. Most of the analytes were not detected in all stations except nonylphenol and S-benzyl-O,O-di-isopropyl phosphorothioate (IBP). Concentrations of nonylphenol and IBP ranged from ND to 298 ng/l and from ND to 1840 ng/l, respectively. The high levels of nonylphenol and IBP were found in the estuary areas of Mangyeong and Dongjin River. The levels of nonylphenol and IBP in surface seawater varied through seasons and the high levels of nonylphenol and IBP were in summer season (August). Based on real time monitoring of IBP and on correlation between concentrations of target compounds and contents of salinity in seawater, physical mixing and diffusion of seawater were found to be the major factors that affect the spatial distribution of IBP and nonylphenol in the Saemangeum Bay environment.  相似文献   

An anisotropic hardening constitutive model based on Generalized Isotropic Hardening rule for modelling clay behaviour     

Seung R. Lee  Seboong Oh 《国际地质力学数值与分析法杂志》1995,19(10):683-703

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