This study reports the magnitude, spatial pattern and temporal trend of near-surface wind speed (NWS) by comparing 20th century simulations in Coupled Model Intercomparison Project phase 5 (CMIP5) and 3 (CMIP3) and the climate reanalyses with measurements at 563 weather stations in China over 1961-2005. Both CMIP5 and CMIP3 agree quite well with observations in reproducing the spatial pattern of annual mean NWS. CMIP5 models are superior to CMIP3 models in hindcasting the magnitude and spatial pattern of seasonal mean NWS, the temporal trend in annual and seasonal mean NWS. Although both CMIP3 and CMIP5 reproduced the decline trend in the annual and seasonal mean NWS, the hindcasted decline rate is smaller than observed decline trend by the magnitude of one order. The ensemble of optimal models that are better correlated to observations in both NWS and temporal trend possesses advantages over individual model hindcast and reanalyses. The reanalyzed data are not able to represent the observed either the spatial pattern or the decline trend of NWS. The analyses presented here reveal the uncertainties in the current wind field products including reanalyses and model outputs and highlight the benefits of parameterization development and increased horizontal resolution in the new-generation CMIP models.
:The precipitation thermodynamic of TiN in ferritic stainless steel has been extensively researched. However, few works referring to the thermodynamics of TiN precipitation heterogeneously is performed. Thermodynamic calculation of TiN shows that TiN does not precipitate during the melting process in B439M ferritic stainless steel. During solidification, the content of Ti and N in the liquid is increased by 7.4 and 3.2 times the initial composition at the end of solidification. The EDS mapping and thermodynamics calculations of MgO and Al 2 O 3 show that the Mg-Al spinel (MgO•Al 2 O 3 ) will form preferentially in the melts. As a result, the composite inclusion can be observed in the microstructure. First, TiN can nucleate heterogeneously with MgO and Al 2 O 3 oxides acting as heterogeneous sites. Then, NbC will nucleate with TiN as the core to form the composite include, which is in agreement with the calculated results. This can provide experimental evidences that in ferritic stainless steels, Ti tends to combine with N to form TiN, and Nb is prone to combine with C to form NbC.
Key words:B439Ferritic stainless steel;TiN inclusion;solidification precipitation;thermodynamics analysis 0 前言 *
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