Creat membership Creat membership
Sign in

Forgot password?

  • Forgot password?
    Sign Up
  • Confirm
    Sign In
home > search

Now showing items 17 - 32 of 378


    Acquisition of data by managing crosstalk interference with sector designs and unique sweeps is conducted and the resultant data are processed in 3D common receiver domain to attenuate crosstalk noise while preserving the signals for high source and receiver density acquisition designs. High-amplitude spectral amplitudes are attenuated and inter-ensemble statics or structural time delays are applied to achieve optimum filter performance. If the spectral amplitudes have been attenuated to a level consistent with non-simultaneous acquisition, conventional surface consistent processing can be performed to correct for statics and amplitude variations. A 3-point filter in different frequency bands may then be applied to remove any remaining residual crosstalk noise.
    Download Collect

    The present invention relates to the fields of organic synthesis and pharmaceutical chemistry, and specifically relates to a β-elemene 14-position derivative (I) or (II), wherein R1 and R2 are defined in the description. Also disclosed in the present invention are a method for preparing said β-elemene 14-position derivatives and the anti-atherosclerotic application of same.
    Download Collect

    The present invention relates to the fields of organic synthesis and pharmaceutical chemistry, and specifically relates to a β-elemene 13-position derivative (I) or (II), wherein R1 and R2 are defined in the description. Also disclosed in the present invention are a method for preparing said β-elemene 13-position derivatives and the anti-atherosclerotic application of same.
    Download Collect
  • Domino Aryne Annulation via Nucleophilic-Ene Process

    Xu, Hai   He, Jia   Shi, Jiarong   Tan, Liang   Qiu, Dachuan   Luo, Xiaohua   Li, Yang  

    Download Collect
  • Growth response ofMicrocystisspp. to iron enrichment in different regions of Lake Taihu, China

    Xu, Hai   Zhu, Guangwei   Qin, Boqiang   Paerl, Hans W.  

    Iron (Fe) is an essential micronutrient for algal growth and can be a potential limiting nutrient in aquatic system, especially regions that exhibits nitrogen (N) limitation. Using short-term nutrient addition bioassays, we evaluated the potential role that iron might play in modifying the response of Microcystis spp. to the anthropogenic phosphorus (P) and N enrichment in hypereutrophic Lake Taihu, the third largest freshwater lake in China. Three nutrient enrichment experiments involving additions of N (as NO3-) and P (as PO43-) with and without Fe were conducted during 2009-2010 in Meiliang Bay, a region characterized by summer cyanobacterial (Microcystis spp.) blooms, and East Taihu, a region largely free of cyanobacterial blooms and dominated by macrophytes. In Meiliang Bay, Fe addition alone did not significantly increase Microcystis spp. biomass. However, Fe addition occasionally increased the stimulatory effect of N and P additions on Microcystis spp., indicating that Fe was not a primary limiting nutrient for Microcystis spp. growth. Occasionally Fe was co-limiting with N and P in this region. In East Taihu, the addition of Fe alone significantly stimulated Microcystis spp. growth, while addition of N and/or P had no effects on growth, indicating that Fe was a primary limiting nutrient in East Taihu. The combined addition of Fe and N resulted in a growth response similar to Fe alone, while combined addition of Fe and P yielded greater biomass increases than the addition of Fe alone. This indicated that in East Taihu, N was not limiting and Fe and P supplies facilitated Microcystis spp. growth. These results reflect differential availabilities and limitations of N, P, and Fe in distinct regions of Taihu. The potential role of Fe in eutrophication dynamics of large, regionally complex lakes like Taihu requires further attention.
    Download Collect
  • Decadal/multi-decadal temperature discrepancies along the eastern margin of the Tibetan Plateau

    Xu, Hai   Sheng, Enguo   Lan, Jianghu   Liu, Bin   Yu, Keke   Che, Shuai  

    Knowledge of the synchronicity and discrepancy of temperature variations along the Eastern margin of the Tibetan Plateau (ETP) is critical in understanding the driving forcing of regional temperature variations. In this study, we established delta 15N timeseries in organic matter and delta 13C timeseries in ostracod shells from sediments of Lake Lugu and attributed their variations to decadal/multi-decadal temperature variations. We compared temperature variations along the ETP transect during the past four centuries based on our presently developed and previously developed temperature proxy indices, as well as temperature variations reconstructed by other researchers. We found that: (1) Over the north ETP area (N-ETP), the decadal/multi-decadal variations in temperature correlate well with each other. (2) Over the south ETP area (S-ETP), temperature variations correlate not so well with each other; while those at south to west portion of the Tibetan Plateau are rather local. (3) The decadal variations in temperature are generally synchronous with those in precipitation over the N-ETP area, and they are broadly anti-phase/out-of-phase with the corresponding ones over the S-ETP area. (4) The long term temperature and precipitation trends are coupling over the N-ETP but decoupling over the S-ETP. We speculate that because the N-ETP is located at the frontier of the Asian summer monsoon (ASM) region, temperature variations there are not as strongly influenced by the ASM; they are most likely dominated by changes in solar activities, and show general similarity to the average of the Northern Hemisphere. Over the S-ETP area, decadal temperature variations are obviously influenced by precipitation. Because the decadal/multi-decadal precipitation variations are anti-phase and/or out-of-phase between the N-ETP and S-ETP, the decadal/multi-decadal temperature variations between these two regions are also anti-phase and/or out-of-phase. [All rights reserved Elsevier].
    Download Collect
  • Modern carbon burial in Lake Qinghai, China

    Xu, Hai   Lan, Jianghu   Liu, Bin   Sheng, Enguo   Yeager, Kevin M.  

    The quantification of carbon burial in lake sediments, and carbon fluxes derived from different origins are crucial to understand modern lacustrine carbon budgets, and to assess the role of lakes in the global carbon cycle. In this study, we estimated carbon burial in the sediment of Lake Qinghai, the largest inland lake in China, and the carbon fluxes derived from different origins. We find that: (1) The organic carbon burial rate in lake sediment is approximately 7.23 g m (2) a (1), which is comparable to rates documented in many large lakes worldwide. We determined that the flux of riverine particulate organic carbon (POC) is approximately 10 times higher than that of dissolved organic carbon (DOC). Organic matter in lake sediments is primarily derived from POC in lake water, of which approximately 80% is of terrestrial origin. (2) The inorganic carbon burial rate in lake sediment is slightly higher than that of organic carbon. The flux of riverine dissolved inorganic carbon (DIC) is approximately 20 times that of DOC, and more than 70% of the riverine DIC is drawn directly and/or indirectly from atmospheric CO2. (3) Both DIC and DOC are concentrated in lake water, suggesting that the lake serves as a sink for both organic and inorganic carbon over long term timescales. (4) Our analysis suggests that the carbon burial rates in Lake Qinghai would be much higher in warmer climatic periods than in cold ones, implying a growing role in the global carbon cycle under a continued global warming scenario. (C) 2013 Elsevier Ltd. All rights reserved.
    Download Collect
  • An SFL approach to gender ideology in the sentence examples in the Contemporary Chinese Dictionary

    Hu, Huilian   Xu, Hai   Hao, Junjie  

    Download Collect
  • Organic field-effect transistors based on pyridine-terminated tetrathiafulvalene (TTF) derivatives

    Xu, Hai   Lin, Gaobo   Zhao, Siqi   Liang, Yong   Xiao, Xunwen   Xu, Wei   Zhu, Daoben  

    Download Collect
  • A highly selective, colorimetric and ratiometric fluorescent probe for NH 2 NH 2 and its bioimaging

    Xu, Hai   Gu, Biao   Li, Yaqian   Huang, Zheng   Su, Wei   Duan, Xiaoli   Yin, Peng   Li, Haitao   Yao, Shouzhuo  

    Download Collect
  • Magnetic properties of ultrathin Co films on Si (111)

    Xu, Hai   Huan, Alfred C.H.   Wee, Andrew T.S.   Tong, D.M.  

    Ultrathin cobalt films on clean (7×7) and Au covered Si (111) substrates were prepared by molecular beam epitaxy. The structure was studied by using scanning tunnelling microscopy and low energy electron diffraction. Magnetic properties were determined with the magneto-optic Kerr effect. It was found that Co nucleates in grains that prefer to grow along the bunched step edges of the Si substrate ([112] direction), which induces a strong in-plane uniaxial anisotropy. By introducing Au buffer layers, the magnetic characteristics were improved by preventing the silicide reaction between Si and Co. Moreover, the tendency for step decoration disappears gradually results in the in-plane uniaxial anisotropy reduction.
    Download Collect
  • Impact of nutrient loading on phytoplankton: a mesocosm experiment in the eutrophic Lake Taihu, China

    Ding, Yanqing   Xu, Hai   Deng, Jianming   Qin, Boqiang   He, Youwen  

    Download Collect
  • Long-term nutrient trends and harmful cyanobacterial bloom potential in hypertrophic Lake Taihu, China

    Xu, Hai   Paerl, Hans W.   Zhu, Guangwei   Qin, Boqiang   Hall, Nathan S.   Zhu, Mengyuan  

    Download Collect
  • Crystal structure of 2-(4-acetyl-2,6-dimethyl-phenyl)-5,6-dichloro-isoindole-1,3-dione, C18H13Cl2NO3

    Li, Feng-Cui   Shi, Qi-Lin   Zhou, Xiao-Hu   Ren, Yang   Xu, Hai  

    Download Collect
  • Desmoid-Type Fibromatosis of the Thorax

    Xu, Hai   Koo, Hyun Jung   Lim, Soyeoun   Lee, Jae Wook   Lee, Han Na   Kim, Dong Kwan   Song, Joon Seon   Kim, Mi Young  

    Download Collect
  • Atomic force microscope characterization of self-assembly behaviors of cyclo[8] pyrrole on solid substrates

    Xu, Hai   Zhao, Siqi   Xiong, Xiang   Jiang, Jinzhi   Xu, Wei   Zhu, Daoben   Zhang, Yi   Liang, Wenjie   Cai, Jianfeng  

    In summary, CP is found to self-assemble into distinct morphological structures under different environmental conditions: this macro cyclic conjugated molecule self organized into nanospheres and nanofibers accompanying natural evaporation of its butanol and toluene solutions on mica, silica and HOPG, respectively. Intermolecular π-π bonding and electronic attraction is believed to be involved in the self-association processes, and affinity or likeness of the solvent molecules and the molecule-surface interactions may be responsible for the molecules to vary their assembly structures in response to the changes in their solvent and substrate. The constructions of nanosized fibers may found applications in the field of supramolecular electronics.
    Download Collect
1 2 3 4 5 6 7 8 9 10


If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

Submit Feedback