We report the near-stoichiometric Ti：LiNbO3 strip waveguides fabricated by vapour transport equilibration （VTE） at 1060~^{／circ}C for 12 h and co-diffusion of 4--8~／mu m wide, 115-nm thick Ti-strips. Optical stud...We report the near-stoichiometric Ti：LiNbO3 strip waveguides fabricated by vapour transport equilibration （VTE） at 1060~^{／circ}C for 12 h and co-diffusion of 4--8~／mu m wide, 115-nm thick Ti-strips. Optical studies show that these waveguides are monomode at 1.5~／mu m and have losses of 1.3 and 1.1~dB/cm for the TM and TE modes, respectively. In the waveguide width/depth direction, the mode field follows a Gauss/Hermite--Gauss profile. A secondary ion mass spectrometry study reveals that the Ti profile follows a sum of two error functions along the width direction and a complementary error function in the depth direction. Micro-Raman analysis shows that the Li-composition in the depth direction also follows a complementary error function. The mean Li/Nb ratio in the waveguide layer is about 0.98. The inhomogeneous Li-composition profile results in a varied substrate index in the guiding layer, and the refractive index profile in the guiding layer is given.展开更多
Using simultaneously collected remote sensing data and field measurements, this study firstly assessed the consistency and applicability of China high-resolution earth observation system satellite 1 （GF-1） wide fiel...Using simultaneously collected remote sensing data and field measurements, this study firstly assessed the consistency and applicability of China high-resolution earth observation system satellite 1 （GF-1） wide field of view （WFV） camera, environment and disaster monitoring and forecasting satellite （H J-l） charge coupled device （CCD）, and Landsat-8 opera- tional land imager （OLI） data for estimating the leaf area index （LAI） of winter wheat via reflectance and vegetation indices （VIs）. The accuracies of these LAI estimates were then assessed through comparison with an empirical model and the PROSAIL radiative transfer model. The effects of radiation calibration, spectral response functions, and spatial resolution on discrepancies in the LAI estimates between the different sensors were also analyzed. The results yielded the following observations： （1） The correlation between reflectance from different sensors is relative good, with the adjusted coefficients of determination （R2） between 0.375 to 0.818. The differences in reflectance are ranging from 0.002 to 0.054. The correlation between VIs from different sensors is high with the R2 between 0.729 and 0.933. The differences in the VIs are ranging from 0.07 to 0.156. These results show the three sensors＇ images can all be used for cross calibration of the reflectance and VIs. （2） The four VIs from the three sensors are all demonstrated to be highly correlated with LAI （R2 between 0.703 and 0.849）. The linear models associated with the 2-band enhanced vegetation index （EVI2）, which feature the highest R2 （higher than 0.746） and the lowest root mean square errors （RMSE） （less than 0.21）, were selected to estimate the winter wheat LAI. The accuracy of the estimated LAI from Landsat-8 was the highest, with the relative errors （RE） of 2.18% and an RMSE of 0.13, while the H J-1 was the lowest, with the RE of 2.43% and the RMSE of 0.15. （3） The inversion errors in the different sensors＇ LAI estimates using the PROSAIL model are small. The accuracy of the GF-1 is the highest with the RE of 3.44%, and the RMSE of 0.22, whereas that of the H J-1 is the lowest with the RE of 4.95%, and the RMSE of 0.26. （4） The effects of the spectral response function and radiation calibration for the different sensors are small and can be ignored, but the effects of spatial resolution are significant and must be taken into consideration in practical applications.展开更多
Labile organic carbon （LOC） and carbon management index （CMI）, which are sensitive factors to the changes of environment, can improve evaluating the effect of land management practices changes on soil quality. The...Labile organic carbon （LOC） and carbon management index （CMI）, which are sensitive factors to the changes of environment, can improve evaluating the effect of land management practices changes on soil quality. The objective of this study was to investigate the effects of land use types and landscape positions on soil quality as a function of L0C and CMI. A field study in a small watershed in the red soil hilly region of southern China was conducted, and soil samples were collected from four typical lands （pine forest （PF） on slope land, barren hill （BH） on slope land, citrus orchard （C0） on terrace land and Cinnarnornum Camphora （CC） on terrace land） at a sampling depth of 20 cm. Soil nutrients, soil organic carbon （SOC）, L0C and CMI were measured. Results showed that the L0C and CMI correlated to not only soil carbon but also soil nutrients, and the values of LOC and CMI in different land use types followed the order CC 〉 PF 〉 CO 〉 BH at the upper- slope, while CO 〉 CC 〉 BH 〉 PF at mid-slope and down-slope. With respect to slope positions, the values of LOC and CMI in all the lands were followed the order： upper-slope 〉 down-slope 〉 mid- slope. As whole, the mean values of LOC and CMI in different lands followed the order CC 〉 CO 〉 PF 〉 BH. High CMI and LOC content were found in the terrace lands with broadleaf vegetations. These results indicated that the terracing and appropriate vegetations can increase the carbon input and lability and decrease soil erosion. However, the carbon pools and CMI in these lands were significantly lower than that in reference site. This suggested that it may require a long time for the soil to return to a high~ quality. Consequently, it is an efficient way to adopt the measures of terracing and appropriate vegetations planting in improving the content of LOC and CMI and controlling water and soil loss in fragile ecosystems.展开更多
Alexey V. ELISEEV; Igor I. MOKHOV; Uncertainty of Climate Response to Natural and An-thropogenic Forcings Due to Different Land Use Scenarios; （5）, 1215-1232 Atsumu OHMURA; see CHEN Linling et al.; （5）, 1030 -10...Alexey V. ELISEEV; Igor I. MOKHOV; Uncertainty of Climate Response to Natural and An-thropogenic Forcings Due to Different Land Use Scenarios; （5）, 1215-1232 Atsumu OHMURA; see CHEN Linling et al.; （5）, 1030 -1038 BAI Jie; GE Quansheng; DAI Junhu; The Response of First Flowering Dates to Abrupt Climate Change in Beijing; （3）, 56-572展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 50872089 and 60577012)the Research Grants Council of the Hong Kong Special Administrative Region, China (Grant No. CityU 1194/07)
文摘We report the near-stoichiometric Ti：LiNbO3 strip waveguides fabricated by vapour transport equilibration （VTE） at 1060~^{／circ}C for 12 h and co-diffusion of 4--8~／mu m wide, 115-nm thick Ti-strips. Optical studies show that these waveguides are monomode at 1.5~／mu m and have losses of 1.3 and 1.1~dB/cm for the TM and TE modes, respectively. In the waveguide width/depth direction, the mode field follows a Gauss/Hermite--Gauss profile. A secondary ion mass spectrometry study reveals that the Ti profile follows a sum of two error functions along the width direction and a complementary error function in the depth direction. Micro-Raman analysis shows that the Li-composition in the depth direction also follows a complementary error function. The mean Li/Nb ratio in the waveguide layer is about 0.98. The inhomogeneous Li-composition profile results in a varied substrate index in the guiding layer, and the refractive index profile in the guiding layer is given.
基金supported by the National Natural Science Foundation of China (41371396,41401491 and 41471364)the Introduction of International Advanced Agricultural Science and Technology,Ministry of Agriculture,China (948 Program,2011-G6)the Agricultural Scientific Research Fund of Outstanding Talents and the Open Fund for the Key Laboratory of Agri-informatics,Ministry of Agriculture,China (2013009)
文摘Using simultaneously collected remote sensing data and field measurements, this study firstly assessed the consistency and applicability of China high-resolution earth observation system satellite 1 （GF-1） wide field of view （WFV） camera, environment and disaster monitoring and forecasting satellite （H J-l） charge coupled device （CCD）, and Landsat-8 opera- tional land imager （OLI） data for estimating the leaf area index （LAI） of winter wheat via reflectance and vegetation indices （VIs）. The accuracies of these LAI estimates were then assessed through comparison with an empirical model and the PROSAIL radiative transfer model. The effects of radiation calibration, spectral response functions, and spatial resolution on discrepancies in the LAI estimates between the different sensors were also analyzed. The results yielded the following observations： （1） The correlation between reflectance from different sensors is relative good, with the adjusted coefficients of determination （R2） between 0.375 to 0.818. The differences in reflectance are ranging from 0.002 to 0.054. The correlation between VIs from different sensors is high with the R2 between 0.729 and 0.933. The differences in the VIs are ranging from 0.07 to 0.156. These results show the three sensors＇ images can all be used for cross calibration of the reflectance and VIs. （2） The four VIs from the three sensors are all demonstrated to be highly correlated with LAI （R2 between 0.703 and 0.849）. The linear models associated with the 2-band enhanced vegetation index （EVI2）, which feature the highest R2 （higher than 0.746） and the lowest root mean square errors （RMSE） （less than 0.21）, were selected to estimate the winter wheat LAI. The accuracy of the estimated LAI from Landsat-8 was the highest, with the relative errors （RE） of 2.18% and an RMSE of 0.13, while the H J-1 was the lowest, with the RE of 2.43% and the RMSE of 0.15. （3） The inversion errors in the different sensors＇ LAI estimates using the PROSAIL model are small. The accuracy of the GF-1 is the highest with the RE of 3.44%, and the RMSE of 0.22, whereas that of the H J-1 is the lowest with the RE of 4.95%, and the RMSE of 0.26. （4） The effects of the spectral response function and radiation calibration for the different sensors are small and can be ignored, but the effects of spatial resolution are significant and must be taken into consideration in practical applications.
基金financially supported by the National Natural Science Foundation of China (41271294)the Program for New Century Excellent Talents in University (NCET-09-330)the Natural Science Foundation of Hunan Province of China (11JJ3041)
文摘Labile organic carbon （LOC） and carbon management index （CMI）, which are sensitive factors to the changes of environment, can improve evaluating the effect of land management practices changes on soil quality. The objective of this study was to investigate the effects of land use types and landscape positions on soil quality as a function of L0C and CMI. A field study in a small watershed in the red soil hilly region of southern China was conducted, and soil samples were collected from four typical lands （pine forest （PF） on slope land, barren hill （BH） on slope land, citrus orchard （C0） on terrace land and Cinnarnornum Camphora （CC） on terrace land） at a sampling depth of 20 cm. Soil nutrients, soil organic carbon （SOC）, L0C and CMI were measured. Results showed that the L0C and CMI correlated to not only soil carbon but also soil nutrients, and the values of LOC and CMI in different land use types followed the order CC 〉 PF 〉 CO 〉 BH at the upper- slope, while CO 〉 CC 〉 BH 〉 PF at mid-slope and down-slope. With respect to slope positions, the values of LOC and CMI in all the lands were followed the order： upper-slope 〉 down-slope 〉 mid- slope. As whole, the mean values of LOC and CMI in different lands followed the order CC 〉 CO 〉 PF 〉 BH. High CMI and LOC content were found in the terrace lands with broadleaf vegetations. These results indicated that the terracing and appropriate vegetations can increase the carbon input and lability and decrease soil erosion. However, the carbon pools and CMI in these lands were significantly lower than that in reference site. This suggested that it may require a long time for the soil to return to a high~ quality. Consequently, it is an efficient way to adopt the measures of terracing and appropriate vegetations planting in improving the content of LOC and CMI and controlling water and soil loss in fragile ecosystems.
文摘Alexey V. ELISEEV; Igor I. MOKHOV; Uncertainty of Climate Response to Natural and An-thropogenic Forcings Due to Different Land Use Scenarios; （5）, 1215-1232 Atsumu OHMURA; see CHEN Linling et al.; （5）, 1030 -1038 BAI Jie; GE Quansheng; DAI Junhu; The Response of First Flowering Dates to Abrupt Climate Change in Beijing; （3）, 56-572
