20 resultados para U.S. Coast and Geodetic Survey

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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The mean sea surface heights (sea surface topography) of the South China, East China, Yellow and Bohai Seas are derived from an ocean general circulation model and surface air pressure. The circulation model covers the global oceans, with fine grid (1/6degrees) covering the East Asian marginal seas and coarse grid (31) covering the rest part of the global oceans. The result shows that the China 1985 National Altitude Datum is 24.7 cm above the me-an sea surface height of the world oceans. The mean sea surface in the coastal ocean adjacent to China is higher in the south than in the north. Intercomparison of the model results with the geodetic leveling measurements at 28 coastal tidal stations shows a standard deviation of 4.8 cm and a fitting coefficient of 95.3%. After correction through linear regression, the standard deviation is reduced to 4.5 cm. This indicates that the accuracy of model results is sufficient for practical application. Based on the model results, the mean sea surface heights for the study area with a resolution of 1/6 degree are given. This result also links the mean sea levels at islands with those on the mainland coast and gives the mean sea surface heights at tidal stations in the Taiwan Island, the Dongsha Islands, the Yisha Islands and the Nansha Islands relative to the China 1985 National Altitude Datum.

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Mid-ocean ridge basalt (MORB) samples from the East Pacific Rise (EPR 12 degrees 50'N) were analyzed for U-series isotopes and compositions of plagioclase-hosted melt inclusions. The Ra-226 and Th-230 excesses are negatively correlated; the Ra-226 excess is positively correlated with Mg# and Sm/Nd, and is negatively correlated with La/Sm and Fe-8; the Th-230 excess is positively correlated with Fe-8 and La/Sm and is negatively correlated with Mg# and Sm/Nd. Interpretation of these correlations is critical for understanding the magmatic process. There are two models (the dynamic model and the "two-porosity" model) for interpreting these correlations, however, some crucial parameters used in these models are not ascertained. We propose instead a model to explain the U-series isotopic compositions based on the control of melt density variation. For melting either peridotite or the "marble-cake" mantle, the FeOt content, Th-230 excess and La/Sm ratio increases and Sm/Nd decreases with increasing pressure. A deep melt will evolve to a higher density and lower Mg# than a shallow melt, the former corresponds to a long residence time, which lowers the Ra-226 excess significantly. This model is supported by the existence of low Ra-226 excesses and high Th-230 excesses in MORBs having a high Fe-8 content and high density. The positive correlation of Ra-226 excess and magma liquidus temperature implies that the shallow melt is cooled less than the deep melt due to its low density and short residence time. The correlations among Fe-8, Ti-8 and Ca-8/Al-8 in plagioclase-hosted melt inclusions further prove that MORBs are formed from melts having a negative correlation in melting depths and degrees. The negative correlation of Ra-226 excess vs. chemical diversity index (standard deviation of Fe-8, Ti-8 and Ca-8/Al-8) of the melt inclusions is in accordance with the influence of a density-controlled magma residence time. We conclude that the magma density variation exerts significant control on residence time and U-series isotopic compositions. (c) 2010 Elsevier B.V. All rights reserved.

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The relationship between monthly sea-level data measured at stations located along the Chinese coast and concurrent large-scale atmospheric forcing in the period 1960-1990 is examined. It is found that sea-level varies quite coherently along the whole coast, despite the geographical extension of the station set. A canonical correlation analysis between sea-level and sea-level pressure (SLP) indicates that a great part of the sea-level variability can be explained by the action of the wind stress on the ocean surface. The relationship between sea-level and sea-level pressure is analyzed separately for the summer and winter half-years. In winter, one factor affecting sea-level variability at all stations is the SLP contrast between the continent and the Pacific Ocean, hence the intensity of the winter Monsoon circulation. Another factor that affects coherently all stations is the intensity of the zonal circulation at mid-latitudes. In the summer half year, on the other hand, the influence of SLP on sea-level is spatially less coherent: the stations in the Yellow Sea are affected by a more localized circulation anomaly pattern, whereas the rest of the stations is more directly connected to the intensity of the zonal circulation. Based on this analysis, statistical models (different for summer and winter) to hindcast coastal sealevel anomalies from the large-scale SLP field are formulated. These models have been tested by fitting their internal parameters in a test period and reproducing reasonably the sea-level evolution in an independent period. These statistical models are also used to estimate the contribution of the changes of the atmospheric circulation on sea-level along the Chinese coast in an altered climate. For this purpose the ouput of 150 year-long experiment with the coupled ocean-atmosphere model ECHAM1-LSG has been analyzed, in which the atmospheric concentration of greenhouse gases was continuously increased from 1940 until 2090, according to the Scenario A projection of the Intergovermental Panel on Climate Change. In this experiment the meridional (zonal) circulation relevant for sea-level tends to become weaker (stronger) in the winter half year and stronger (weaker) in summer. The estimated contribution of this atmospheric circulation changes to coastal sea-level is of the order of a few centimeters at the end of the integration, being in winter negative in the Yellow Sea and positive in the China Sea with opposite signs in the summer half-year.

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Based on Th-230-U-238 disequilibrium and major element data from mid-ocean ridge basalts (MORBs) and ocean island basalts (OIBs), this study calculates mantle melting parameters, and thereby investigates the origin of Th-230 excess. (Th-230/U-238) in global MORBs shows a positive correlation with Fe-8, P (o), Na-8, and F-melt (Fe-8 and Na-8 are FeO and Na2O contents respectively after correction for crustal fractionation relative to MgO = 8 wt%, P (o)=pressure of initial melting and F (melt)=degree of melt), while Th-230 excess in OIBs has no obvious correlation with either initial mantle melting depth or the average degree of mantle melting. Furthermore, compared with the MORBs, higher (Th-230/U-238) in OIBs actually corresponds to a lower melting degree. This suggests that the Th-230 excess in MORBs is controlled by mantle melting conditions, while the Th-230 excess in OIBs is more likely related to the deep garnet control. The vast majority of calculated initial melting pressures of MORBs with excess Th-230 are between 1.0 and 2.5 GPa, which is consistent with the conclusion from experiments in recent years that D (U)> D (Th) for Al-clinopyroxene at pressures of > 1.0 GPa. The initial melting pressure of OIBs is 2.2-3.5 GPa (around the spinel-garnet transition zone), with their low excess Ra-226 compared to MORBs also suggesting a deeper mantle source. Accordingly, excess Th-230 in MORBs and OIBs may be formed respectively in the spinel and garnet stability field. In addition, there is no obvious correlation of K2O/TiO2 with (Th-230/U-238) and initial melting pressure (P (o)) of MORBs, so it is proposed that the melting depth producing excess Th-230 does not tap the spinel-garnet transition zone. OIBs and MORBs in both (Th-230/U-238) vs. K2O/TiO2 and (Th-230/U-238) vs. P (o) plots fall in two distinct areas, indicating that the mineral phases which dominate their excess Th-230 are different. Ce/Yb-Ce curves of fast and slow ridge MORBs are similar, while, in comparison, the Ce/Yb-Ce curve for OIBs shows more influence from garnet. The mechanisms generating excess Th-230 in MORBs and OIBs are significantly different, with formation of excess Th-230 in the garnet zone only being suitable for OIBs.

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By using characteristic analysis of the linear and nonlinear parabolic stability equations (PSE), PSE of primitive disturbance variables are proved to be parabolic intotal. By using sub-characteristic analysis of PSE, the linear PSE are proved to be elliptical and hyperbolic-parabolic for velocity U, in subsonic and supersonic, respectively; the nonlinear PSE are proved to be elliptical and hyperbolic-parabolic for relocity U + u in subsonic and supersonic, respectively. The methods are gained that the remained ellipticity is removed from the PSE by characteristic and sub-characteristic theories, the results for the linear PSE are consistent with the known results, and the influence of the Mach number is also given out. At the same time, the methods of removing the remained ellipticity are further obtained from the nonlinear PSE.

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In continuation of our program aimed at the discovery and development of compounds with superior anti-human immunodeficiency virus type 1 (HIV-1) activity, 21N-arylsulfonyl-3-acetylindole analogs (2a-u) were synthesized and preliminarily evaluated as HIV-1 inhibitors in vitro. Among of all the analogs, several compounds exhibited significant anti-HIV-1 activity, especially N-phenylsulfonyl-3-acetyl-6-methylindole (2j) and N-(p-ethyl)phenylsulfonyl-3-acetyl-6-methylindole (2n) showed the most potent anti-HIV-1 activity with EC50 values of 0.36 and 0.13 mu g/mL, and TI values of >555.55 and 791.85, respectively. It demonstrated that introduction of the acetyl group at the 3-position of N-arylsulfonyl-6-methylindoles could generally lead to the more potent analogs. (C) 2010 Elsevier Ltd. All rights reserved.

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Invasive alien species have become one of the most serious environmental issues in the world. Data of taxon, origin, pathway, and environmental impacts of invasive alien microorganisms, invertebrates, amphibians and reptiles, fish, birds, mammals, herbs, trees, and, marine organisms in terrestrial, aquatic, and marine ecosystems of China were analyzed during 2001 and 2003, based on literature retrieval and field survey. There were 283 invasive alien species in China, and the number of species of invasive alien microorganisms, aquatic plants, terrestrial plants, aquatic invertebrates, terrestrial invertebrates, amphibians and reptiles, fish, and mammals were 19, 18, 170, 25, 33, 3, 10, and 5, respectively. The proportion of invasive alien species originated from America, Europe, Asia, Africa, and Oceania were 55.1, 21.7, 9.9, 8.1, and 0.6%, respectively. Methods for estimation of direct economic losses to agriculture, forestry, stockbreeding, fishery, road and water transportation, storage, water conservancy, environment and public facilities, and human health were established. Methods for estimation of indirect economic losses caused by invasive alien species to service functions of forest ecosystems, agricultural ecosystems, grassland ecosystems, and wetland ecosystems were also established. The total economic losses caused by invasive alien species to China were to the time of USD 14.45 billion, with direct and indirect economic losses accounting for 16.59% and 83.41% of total economic losses, respectively.

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The electronic structure and mechanical properties Of UC2 and U2C3 have been systematically investigated using first-principles calculations by the projector-augmented-wave (PAW) method. Furthermore, in order to describe precisely the strong on-site Coulomb repulsion among the localized U 5f electrons, we adopt the generalized gradient approximation +U formalisms for the exchange-correlation term. We show that our calculated structural parameters and electronic properties for UC2 and U2C3 are in good agreement with the experimental data by choosing an appropriate Hubbard U = 3 eV. As for the chemical bonding nature, the contour plot of charge density and total density of states suggest that UC2 and U2C3 are metallic mainly contributed by the 5f electrons, mixed with significant covalent component resulted from the strong C-C bonds. The present results also illustrate that the metal-carbon (U-C) bonding and the carbon-carbon covalent bonding in U2C3 are somewhat weaker than those in UC2, leading to the weaker thermodynamic stability at high temperature as observed by experiments.

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DNA damage and cell reproductive death determined by alkaline comet and clonogenic survival assays were examined in Lewis lung carcinoma cells after exposure to 89.63 MeV/u carbon ion and 6 MV X-ray irradiations, respectively. Based on the survival data, Lewis lung carcinoma cells were verified to be more radiosensitive to the carbon ion beam than to the X-ray irradiation. The relative biological effectiveness (RBE) value, which was up to 1.77 at 10% survival level, showed that the DNA damage induced by the high-LET carbon ion beam was more remarkable than that induced by the low-LET X-ray irradiation. The dose response curves of '' Tail DNA (%)'' (TD) and "Olive tail moment" (OTM) for the carbon ion irradiation showed saturation beyond about 8 Gy. This behavior was not found in the X-ray curves. Additionally, the carbon ion beam produced a lower survival fraction at 2 Gy (SF2) value and a higher initial Olive tail moment 2 Gy (OTM2) than those for the X-ray irradiation. These results suggest that carbon ion beams having high-LET values produced more severe cell reproductive death and DNA damage in Lewis lung carcinoma cells in comparison with X-rays and comet assay might be an effective predictive test even combining with clonogenic assay to assess cellular radio sensitivity

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The abzyme (Se-6E8) with a higher thyroxine deiodinase activity was prepared by modifying the serine residues of monoclonal antibody (6E8)with phenylmethanesulfonyl fluoride and sodium hydrogen selenide, and the 6E8 against O-methyl-T-4, which is a kind of thyroxine derivatives and was taken as a hapten for the first time. Two bands were found corresponding to the 5.5 kD heavy chain and the 2.7 kD light chain respectively by SDS-PAGE. The characteristics of dissociation constants, pH, and temperature were also studied. The results show that the activity of Se-6E8 is 2 010 U/mumol protein, and the proper temperature and pH of the catalytic reactions is 57 degreesC and 8.2 respectively.

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Physical properties of thin films of soluble and insoluble aromatic polyimides were compared by d.s.c., u.v.-visible and fluorescence spectroscopy, and prism coupler technique. D.s.c. results showed that the thermal properties of insoluble polyimides are superior to those of soluble ones, owing to the specific molecular interactions of insoluble polyimides, revealed by fluorescence spectroscopy. However, the specific molecular interactions sacrifice the transparency in their thin films, shown by u.v.-visible transmission spectra. Negative birefringence of thin films, not only for soluble polimides but also for polyamic acids of insoluble polyimides, was confirmed by prism coupler, while thin films of insoluble polyimides thermally imidized lack high levels of negative birefringence. It is regarded that thin films of insoluble polyimides thermally imidized are likely to be isotropic because of molecular relaxation above their glass transition temperatures (T-g) in the course of thermal imidization, according to Flory's principle. On the contrary, thin films of insoluble poyimide chemically imidized keep the same levels of negative birefringence as those of the relevant polyamic acid thin films. Judging from the opposite cases, it is recognized that molecular relaxation above T-g weakens the optical anisotropy of polyimide thin films. (C) 1998 Elsevier Science Ltd. All rights reserved.

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BACKGROUND: Previously, tachyplesin gene (tac) has been successfully transferred into Undaria pinnatifida gametophytes using the method of microprojectile bombardment transformation. The objectives of this study were to compare and evaluate the performance of bubble-column and airlift bioreactors to determine a preferred configuration of bioreactor for vegetative propagation of transgenic U. pinnatifida gametophytes, and to then investigate the influence of light on vegetative propagation of these gametophytes, including incident light intensity, photoperiod and light quality to resolve the problems of rapid vegetative propagation within the selected bioreactor. RESULTS: Experimental results showed that final dry cell density in the airlift bioreactor was 12.7% higher than that in the bubble-column bioreactor under the optimal aeration rate of 1.2 L air min(-1) L-1 culture. And a maximum final dry cell density of 2830 mg L-1 was obtained within the airlift bioreactor using blue light at 40 mu mol m(-2) s(-1) with a light/dark cycle of 14/10 (h). Polymerase chain reaction (PCR) analysis indicated that genes (bar and tac) were not lost during rapid vegetative propagation within the airlift bioreactor. CONCLUSION: The airlift bioreactor was shown to be much more suitable for rapid vegetative propagation of transgenic U. pinnatifida gametophytes than the bubble-column bioreactor in the laboratory. The use of blue light allows improvement of vegetative propagation of transgenic U. pinnatifida gametophytes. (C) 2009 Society of Chemical Industry

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Eleven pairs of Undaria pinnatifida (Harv.) Suringar gametophytes were identified with random amplified polymorphic DNA (RAPD) technique. After screening 100 primers, 20 ten-base primers were determined for the RAPD analysis. A total of 312 polymorphic loci were obtained, of which 97.7% were polymorphic. The primer S198 was found to distinguish all the selected Undaria pinnatifida gametophytes. The genetic distances between each two of the twenty-two U. pinnatifida gametophytes ranged from 0.080 to 0.428, while the distances to the Laminaria was 0.497 on average. After reexamination, two sequences characterized amplification region (SCAR) markers were successfully converted, which could be applied to U. pinnatifida germplasm identification. All these results demonstrated the feasibility of applying RAPD markers to germplasm characterization and identification of U. pinnatifida gametophytes, and to provide a molecular basis for Undaria breeding.