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121.
本文用正压模式计算了大尺度湍流输送项对高度倾向的影响,用的是1956年2月13—22日的资料.在这例子中涡度的湍流输送的项作用与平均输送项大小量级相同.这两项所造成的高度倾向分布颇不相同,并不成简单的此例关系. 相似文献
122.
A generation procedure of Ritz vectors to control the inclusion of static effect and the number of vectors in mode superposition dynamic analysis is presented. The original algorithm of the Ritz vectors15 is modified to improve stability in the generation procedure and to include the use of static residual. To reject unimportant Ritz vectors, cut-off criteria, which are based on the participation of mass distribution and spatial load distribution, are proposed. Numerical examples are presented to illustrate the effectiveness of the derived Ritz vectors over the eigenvectors and the performance of the cutoff criteria in the mode superposition dynamic analysis. 相似文献
123.
Chemical and physical weathering in a hot‐arid,tectonically active alluvial system of Anza Borrego Desert,California
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Investigation of chemical and physical weathering of bedrock and alluvial sediment in the Anza Borrego Desert, California, sheds light on weathering processes in hot‐arid systems and clarifies interpretations of climate from alluvial sediment. All of the alluvial sediment in the study area emanates from Cretaceous tonalite of the Peninsular Range, enabling exploration of the effects of external variables – climate, transport distance and tectonics – on the physical and chemical properties of the sediment. Chemical weathering in this area is dominated by plagioclase alteration observed in both bedrock outcrops and sediment, evinced most clearly by changes in the Eu anomaly. Biotite chemical weathering, manifested by interlayer K+ loss, is not evident in bedrock, but clearly observed in the sediment. Despite the weak intensity of chemical weathering (Chemical Index of Alteration = 56 to 62), fine‐grained (<63 μm) sediment displays a clear weathering trend in A–CN–K space and contains up to 25% clay minerals. Physical abrasion and grain‐size reduction in biotite during transport predominates in the sediment, whereas physical (insolation) weathering affecting bedrock is inferred from estimates of differential thermal expansion of mineral phases in response to extreme temperature changes in the study area. Chemical alteration and Brunauer–Emmett–Teller surface area both increase within the active Elsinore fault zone at the distal end of the depositional transect, reflecting tectonic‐induced fracturing and associated accelerated weathering. Extensive fracturing, together with a more humid Pleistocene climate, probably facilitated in situ bedrock weathering, preceding arid alluvial deposition in the Holocene. This study demonstrates that both climate and tectonic processes can affect chemical and physical weathering, resulting in alteration of plagioclase, leaching of K+ from biotite in the sediment and formation of clay minerals, even in hot, arid systems. 相似文献
124.
Flow and transport modeling in the sea-breeze part II: Flow model application and pollutant transport 总被引:2,自引:0,他引:2
A modifiedE- non-hydrostatic model with non-equilibrium level 2.5 closure was applied to the flow and pollutant dynamics in the sea-breeze. The model predicts key observed characteristics of the sea-breeze, such as midday slowing of inland penetration, fast and deep inland penetration in late afternoon, and detachment of the sea-breeze from the feeding flow in early evening. In late evening when the turbulent mixing over the land subsides due to the surface cooling, a frontal density current is formed and the predicted structure is in good agreement with observations and laboratory experiments of density currents. Turbulent mixing over the land is a key parameter that controls midday slowing and late afternoon frontal development.The calculated thermal internal boundary layer and fumigation of an elevated line source show good agreement with observations and similarity theory. Calculations suggest that the residual plume aloft over the sea returns onshore at ground level during the afternoon sea-breeze and has a large impact on ground-level concentrations during the following day. 相似文献
125.
Yong–Joo JWA 《Resource Geology》1998,48(4):273-284
Abstract: Five groups of the Phanerozoic granitoids in South Korea can be deduced from their temporal and spatial distributions: (1) Jurassic granitoids in the Gyeonggi massif, (2) Permo-Jurassic granitoids in the Ogcheon belt, (3) Permo-Jurassic granitoids in the Yeongnam massif, (4) Cretaceous granitoids in the Ogcheon belt, and (5) Cretaceous granitoids in the Gyeongsang basin. Though the granitoids of each group generally show calc-alkaline and orogenic natures, the petrological, geochemical and genetical features are different with each other. The Permo-Jurassic granitoids in the Ogcheon belt have lower contents of Al2O3, Fe2O3, CaO, P2O5, but higher of FeO, FeOT, MgO, K2O than those in the Yeongnam massif. From higher feature of K2O, Na2O+K2O and K2O/Na2O, the Ogcheon belt seems to have been located at closer continent side relative to the Yeongnam massif during Permo-Jurassic time. From lower values of Fe2O3/FeO and magnetic susceptibility the granitoids of the Ogcheon belt had been solidified under more reducing environment than those of the Yeongnam massif. The Cretaceous granitoids in the Ogcheon belt have lower contents of TiO2, Fe2O3, FeO, FeOT, CaO and P2O5, but higher of MgO, K2O, Na2O+K2O and K2O/Na2O than those in the Gyeongsang basin. This feature indicates that the Ogcheon belt would correspond to the continental environment of magma genesis during Cretaceous time. Higher values of Fe2O3/FeO and magnetic susceptibility in the Cretaceous granitoids in the Gyeongsang basin suggest that the granitoids had been solidified under highly oxidizing environment. From the particular chemical features of K2O, Na2O+K2O and K2O/Na2O, the Permo-Jurassic granitoids in the Ogcheon belt, the Yeongnam massif as well as the Cretaceous ones in the Gyeongsang basin can be categorized to the continental margin type granite. The Jurassic granitoids in the Gyeonggi massif are possibly of collision type, and the Cretaceous granitoids in the Ogcheon belt of post–orogenic, intra–conti–nent type. The Jurassic granitoids in the Gyeonggi massif had been possibly generated by crustal melting during the collision of Gyeonggi massif to the northern Pyeongnam basin block. The Cretaceous granitoids in the Ogcheon belt had been emplaced at the hinterland of the continental margin during post-orogenic stage of the Honam Shear Zone. The Cretaceous granitoids in the Gyeongsang basin are often compared with Japanese Cretaceous?Paleogene granitoids in their geochemical and genetical natures. For the granitoid composition, the granitoids in the Gyeongsang basin are higher in Fe2O3, Fe2O3/FeO, Na2O, K2O, Na2O+K2O and K2O/Na2O, but lower in Al2O3, FeO, MnO, CaO and P2O5 than the Japanese granitoids. The contents of TiO2, FeOT and MgO are similar in both granitoids. This geochemical contrast would imply that the Cretaceous granitoid magmas in the Gyeongsang basin had been originated at closer place to the continent side under more tensional field, and solidified under more oxidizing environment than the coeval Japanese granitoid magmas. 相似文献
126.
Palustrine calcretes of the Cretaceous Gyeongsang Supergroup, Korea: Variation and paleoenvironmental implications 总被引:2,自引:0,他引:2
Abstract Mostly siliciclastic lacustrine deposits from five stratigraphically different formations (Jinju Formation, Jindong Formation, Geoncheonri and correlative Hwasan Formations and Dadaepo Formation, in ascending order) in the Cretaceous Gyeongsang Basin, Korea, were examined for aspects of lithofacies and pedogenesis to evaluate the relative influence of geological controls on the development of palustrine calcretes (calcretes formed from palustrine deposits). The pedogenic carbonate development of palustrine deposits in the Gyeongsang Supergroup varies from formation to formation. The highest development is in the Dadaepo Formation and the second is in the Jindong Formation. The lowest development of palustrine calcretes is in the Geoncheonri and Hwasan Formations and the Jinju Formation shows intermediate development. The more negative d13C values and the less negative d18O values of the Dadaepo palustrine calcretes confirm greater pedogenic development in the Dadaepo Formation. That the highest development was in the Dadaepo Formation was attributed to it having the smallest lake size, indicating that lake size is critical to palustrine calcrete development in non‐carbonate lakes under semi‐arid climate. In spite of having the largest lake size, the higher development in the Jindong Formation could have resulted from its lowest lake gradient and most arid paleoclimate. The higher development of palustrine calcretes in the Late Cretaceous deposits (Jindong Formation) than the Early Cretaceous deposits (Jinju Formation) reflect overall increase in aridity throughout the period during the deposition of the Gyeongsang Supergroup. Consequently, the diverse development of the palustrine calcretes in the Gyeongsang Supergroup indicates that the lacustrine settings varied in time and space throughout the evolution of the Cretaceous Gyeongsang Basin. Such variation in palustrine calcrete development according to the change in paleoenvironments may provide a basis to interpret the relative paleoenvironmental condition of lacustrine deposits including paleoclimate, lake size and gradient. 相似文献
127.
128.
Youngwan Seo Hee-Jung Lee You Ah Kim Hyun Joo Youn Burm-Jong Lee 《Ocean Science Journal》2005,40(4):209-212
In the present study, we have tested the effects of 21 salt marsh plants on cell proliferation of mouse immune cells (spleen
and thymus) using MTT assay in culture. The methanolic extracts of six salt marsh plants (Rosa rugosa, Ixeris tamagawaensis, Artemisia capillaris, Tetragonia tetragonoides, Erigeron annus, and Glehnia littoralis) showed very powerful suppressive effects of mouse immune cell death and significant activities of cell proliferationin vitro. Especially, the methanolic extract ofRosa rugosa was found to have fifteen times compared to the control treatment, demonstrating that Rosa rugosa may have a potent stimulation
effect on immune cell proliferation. These results suggest that several salt marsh plants includingRosa rugosa could be useful for further study as an immunomodulating agent. 相似文献
129.
Samples of macrobenthic organisms were obtained at seven stations on a presumed pollution gradient from the head of Vancouver Harbour through to outer Howe Sound. Polychaetes (83 apparent species) and molluscs (43 apparent species) were the most abundant faunal groups numerically (44.8 and 47.9%, respectively). Molluscs accounted for most of the biomass (87.9%). The following univariate and multivariate methods were used to investigate structural changes in the benthic communities: ANOVA, Abundance-Biomass Comparisons and related statistics, cluster analysis, multidimensional scaling, and the BIOENV procedure. Most of the analyses divided the seven stations into three groups: Port Moody Arm (Inner Harbour): two stations; Inner and Outer Harbour: four stations, and Gibsons (Howe Sound): one station. Further cause-effect investigations are needed to determine the sensitivity to organic pollution of indicator species identified in the survey. However our data correlating benthic community changes to sediment chemistry suggest the inner harbour was dominated by pollution-tolerant species. Depth and sediment grain size were confounding factors for the interpretations. 相似文献
130.
Jin Yeong Kim Il Su Choi Joo Il Kim Seok Gwan Choi Young Yull Chun 《Ocean Science Journal》2007,42(1):41-48
We investigated the temperature and salinity effects on the major fish species in the wintering grounds based on trawl surveys
and oceanographic observations in the southwestern waters of Korea during March-early April in 2002-2003. The influence area
of warm Kuroshio water was limited to the southwestern area of Korea in 2003 with a range of 7.7-16.3°C, 32.54-34.70 of salinity,
wider than that of 2002. The number of fish species and density of major fish species in 2003 were higher than in 2002. Geographical
estimation showed high proportions of species number and catches in the areas around Jeju Islands, southwestern waters and
the southeastern coast of Korea. Five species; silver pomfret (Pampus echinogaster), hairtail (Trichiurus lepturus), anchovy (Engraulis japonicus), small yellow croaker (Larimichthys polyactis) and yellow goosefish (Lophius litulon) were most abundant, composing above 60% of the total catch in 2002 and 2003. More than 50% of catch in the major fish species
were mostly distributed in the range of 9.5-11.0°C of temperature and 33.1-33.9 of salinity. Non-parametric estimation for
the major species showed the 1st mode around 10°C and the 2nd mode at 8-9°C in 2002 and 11-14°C in 2003. A m o n g major fish
species, hairtail was principally composed of juveniles, and larger individuals were caught in southeastern waters. These
results are considered to be helpful for the areabased fishery management strategy for the wintering grounds of the Yellow
Sea and coastal waters of Korea. 相似文献