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| 1 | Forest NPP estimation based on MODIS data under cloudless condition显示文摘Based on light-use efficiency model, an MODIS-derived daily net primary production (NPP) model was developed. In this model, a new model for the fraction of photosynthetically active radiation absorbed by vegetation (FPAR) is developed based on leaf area index (LAI) and albedo parameters, and a pho- tosynthetically active radiation (PAR) is calculated from the combination of Bird's model with aerosol optical thickness and water vapor derived from cloud free MODIS images. These two models are inte- grated into our predicted NPP model, whose most parameters are retrieved from MODIS data. In order to validate our NPP model, the observed NPP in the Qianyanzhou station and the Changbai Mountains station are used to compare with our predicted NPP, showing that they are in good agreement. The NASA NPP products also have been downloaded and compared with the measurements, which shows that the NASA NPP products underestimated NPP in the Qianyanzhou station but overestimated in the Changbai Mountains station in 2004. | CHEN LiangFu GAO YanHua LI Li LIU QinHuo GU XingFa | 2008 | Science China Earth Sciences2008,51,3: | 7 |
| 2 | Uncertainty analysis of cross-calibration for HJ-1 CCD camera显示文摘Radiometric calibration of sensor is the basis of quantitative remote sensing,and uncertainty analysis is critical to ensure the accuracy of cross-calibration.Therefore,firstly,cross-calibration formulas were improved by redefining calibration coefficient and spectral band matching factor.In these formulas,cci was redefined as the calibration coefficient of normalized apparent reflectance,and spectral band matching factor as the ratio of normalized apparent reflectance.Secondly,based on the contrast of ideal and actual conditions in cross-calibration,8 sources of cross-calibration uncertainty were proposed:calibration uncertainty of standard sensor;pixel matching uncertainty;spectral band matching factor uncertainty caused by site altitude setting error,atmospheric parameters setting error,surface spectrum source,surface bidirectional reflectance characteristic,and error of atmospheric radiative transfer model;and uncertainty caused by other factors which were not considered.Finally,the contribution of each uncertainty was further analyzed and discussed for the HJ-1 CCD camera.The results provide many valuable references for evaluating the feasibility of alternative cross-calibration measurements. | WANG Zuo XIAO PengFeng GU XingFa FENG XueZhi LI XiaoYing GAO HaiLiang LI Hui LIN JinTang ZHANG XueLiang | 2013 | Chinese Science Bulletin2013,58,7: | 3 |
| 3 | A twin-channel difference model for cross-calibration of thermal infrared band显示文摘Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the limitation that the atmospheric condition when image is acquiring cannot be truly obtained in the traditional radiometric simulation calibration method.The analysis of surface,atmosphere and top-of-atmosphere(TOA) radiative energy decomposition demonstrated that the apparent TOA radiance of the uncalibrated channel is the differential combination of two reference channels.The DM avoids impacts from atmospheric temperature and density.The only impact is from water vapor(WV) content.Based on the fitting error analysis of 742 mid-latitude atmospheric profiles(column WV content:0-5×10 3 atm cm) selected from TIGR database,the DM is insensitive to WV content.The maximum error is less than 0.2 K when the view zenith angels(VZAs) of reference channels and uncalibrated channel are less than 30.The error becomes 0.3 K when VZAs range from 30 to 40 and 0.6 K when VZAs are in 40-50.Because the uncertainty increases when VZAs are larger than 50,the best range of VZAs is 30-50.The vicarious calibration results at Lake Qinghai field indicated that the calibration precision of the DM cross-calibration by using MODIS bands 31 and 32 as reference channels to calibrate IRS band 08 is similar to that of vicarious calibration.Therefore,the DM is a reliable alternative tool for sensor on-orbit calibration and validation with high precision and frequency. | LI JiaGuo GU XingFa YU Tao LI XiaoYing GAO HaiLiang LIU Li XU Hui | 2012 | Science China(Technological Sciences)2012,55,7: | 2 |
| 4 | Hydrazine and thermal reduction of graphene oxide: Reaction mech- anisms,product structures,and reaction design显示文摘 | Gao Xingfa Joonkyung Jang Shigeru Nagase | 2010 | Phys Chem C2010,114,: | 1 |
| 5 | Remote substituent effects on catalytic activity of metal-organic frameworks: a linker orbital energy model显示文摘The Hammett equation is commonly used to theoretically depict the remote electronic effects of substituents on catalytic activitiesof metal nodes of metal-organic frameworks (MOFs). However, the application of the theory to MOF catalysts usually encountersproblems because it relies heavily on empirical parameters with unknown transferability. To develop an alternative predictiontheory, the linker orbital energy model has been proposed by density functional theory calculations. The model provides a simplemethod to approximately depict the remote electronic substituent effects on catalytic activities of metal nodes of MOFs, and itsgeneral applicability to MOFs is supported by extensively revisiting the structure-activity relationships reported in the literatures.The model can be used to design catalytic activity of metal nodes of MOFs by engineering the electronic properties of linkers andsubstituents. | Zhenzhen Wang Huan Meng Xuejiao J.Gao Jia-Jia Zheng Xingfa Gao | 2023 | npj Computational Materials2023,,1: | 1 |
| 6 | Method study and uncertainty analysis of calibration coefficients validation based on the Inner Mongolia test site显示文摘Calibration coefficients validation is the foundation for ascertaining the sensor performance and carrying out the quantitative application.Based on the analysis of the differences between the calibration and validation,two calibration coefficients validation methods were introduced in this paper.Taking the HJ-1A satellite CCD1 camera as an example,the uncertainties of calibration coefficients validation were analyzed.The calibration coefficients validation errors were simulated based on the measured data at an Inner Mongolia test site.The result showed that in the large view angle,the ground directional reflectance variation and the atmospheric path variation were the main error sources in calibration coefficients validation.The ground directional reflectance correction and atmospheric observation angle normalization should be carried out to improve the validation accuracy of calibration coefficients. | GAO HaiLiang GU XingFa YU Tao GONG Hui LI JiaGuo LI XiaoYing | 2013 | Science China Earth Sciences2013,56,9: | 1 |
| 7 | The Way of Stabilizing Non-IPR Fullerenes and Structural Elucidation of C54C18显示文摘 | Gao Xingfa Zhao Yuliang | 2007 | J Comput Chem2007,28,: | 1 |
| 8 | Highly delocalized endohedral metal in Gd@C2v(9)-C82 metallofullerenes co-crystallized with α-Se显示文摘 | Cheng Li Xuejiao J. Gao Huanli Yao Huan Huang Rongli Cui Xihong Guo Lele Zhang Bing Liu Binggang Xu Weiqun Shi Jinquan Dong Lai Feng Xingfa Gao Baoyun Sun | 2018 | Nano Research2018,11,4: | 0 |
| 9 | Plasmonic nanostructures acting as a light-driven O_(2)-sensitive nitroreductase mimic for enhanced photochemical oxidation of para-aminothiophenol显示文摘Nanozymes,as a novel form of enzyme mimics,have garnered considerable interest.Despite overcoming the main disadvantages of their natural analogs,they still face challenges such as restricted mimic types and low substrate specificity.Herein,we introduce a reactive ligand modification strategy to diversify enzyme mimic types.Specifically,we have utilized helical plasmonic nanorods(HPNRs)modified with para-nitrothiophenol(4-NTP)to create an oxygen-sensitive nitroreductase(NTR)with light-controllability.HPNRs act as a light-adjustable source of nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate(NAD(P)H),providing photon-generated energetic electrons to adsorbed 4-NTP molecules.In the presence of O_(2),the activated 4-NTP transfers the captured electron to the adsorbed O_(2),mimicking the electron transfer process in its natural counterpart.This enhanced O_(2)activation notably boosts the oxidative coupling of para-aminothiophenol(4-ATP).Density functional theory(DFT)calculations reveal that hot electrons injected into the lowest unoccupied molecular orbital(LUMO)energy level of 4-NTP can be transferred to that of molecular oxygen.In conclusion,our findings underline the potential of the reactive ligand modification strategy in developing new types of enzyme reactions,which opens up promising avenues for the enhancement and diversification of nanozyme functionalities. | Xinshuang Gao Jia-jia Zheng Hanbo Li Rui Cai Xingfa Gao Xiaochun Wu | 2023 | Nano Research2023,16,11: | 0 |