Here, the geographical space distribution of the oil and gas industry in China is comprehensively investigated using the overal Moran’s I index and local Moran’s I index. We found that China’s oil and gas industry ...Here, the geographical space distribution of the oil and gas industry in China is comprehensively investigated using the overal Moran’s I index and local Moran’s I index. We found that China’s oil and gas industry development from 2000 to 2010 has a differentiated geographical space distribution upstream （extractive industry） but not downstream （reifning industry）. To analyze upstream and downstream states a spatial econometrics model （SEM） was used to identify inlfuential factors resulting from the spatial concentration of the oil and gas industry. An external effect is the key factor promoting the spatial concentration of the upstream industry in China;governmental economic policy is another important factor.展开更多
GaNs grown by hydride vapor phase epitaxy(HVPE) were irradiated by protons with different fluences.The changes of surface topography of as-grown and irradiated samples were characterized by atomic force microscopy(AFM...GaNs grown by hydride vapor phase epitaxy(HVPE) were irradiated by protons with different fluences.The changes of surface topography of as-grown and irradiated samples were characterized by atomic force microscopy(AFM).The crystal quality and optical properties of GaN films were examined by the variations of the micro-Raman and photoluminescence(PL) spectra with proton fluence.It was observed that the surface became a little more rough after irradiation.The Raman spectra indicated that the strain of materials and carrier concentration were not affected by the proton injection.The full-width at half-maximum(FWHM) of E 2 high phonon mode narrowed,which was consistent with the FWHM of PL near-band-edge emission(BE).The spectra of yellow luminescence and blue luminescence normalized to the intensity of BE demonstrated a little increase of Ga vacancy and a large decrease of O N,which may be the main reason for the change of optical properties.展开更多
基金the Key Project of the National Social Science Foundation of China(Grant No.11AJL007)The Ministry of education of Humanities and Social Science project(Grant No.12YJC790082)
文摘Here, the geographical space distribution of the oil and gas industry in China is comprehensively investigated using the overal Moran’s I index and local Moran’s I index. We found that China’s oil and gas industry development from 2000 to 2010 has a differentiated geographical space distribution upstream （extractive industry） but not downstream （reifning industry）. To analyze upstream and downstream states a spatial econometrics model （SEM） was used to identify inlfuential factors resulting from the spatial concentration of the oil and gas industry. An external effect is the key factor promoting the spatial concentration of the upstream industry in China;governmental economic policy is another important factor.
基金supported by the National Natural Science Foundation of China (Grant No. 61106106)the Fundamental Research Funds for the Central Universities (Grant No. K50510250006)
文摘GaNs grown by hydride vapor phase epitaxy(HVPE) were irradiated by protons with different fluences.The changes of surface topography of as-grown and irradiated samples were characterized by atomic force microscopy(AFM).The crystal quality and optical properties of GaN films were examined by the variations of the micro-Raman and photoluminescence(PL) spectra with proton fluence.It was observed that the surface became a little more rough after irradiation.The Raman spectra indicated that the strain of materials and carrier concentration were not affected by the proton injection.The full-width at half-maximum(FWHM) of E 2 high phonon mode narrowed,which was consistent with the FWHM of PL near-band-edge emission(BE).The spectra of yellow luminescence and blue luminescence normalized to the intensity of BE demonstrated a little increase of Ga vacancy and a large decrease of O N,which may be the main reason for the change of optical properties.
