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| 1 | Comparative Analysis of Fractional Vegetation Cover Estimation Based on Multi-sensor Data in a Semi-arid Sandy Area显示文摘The estimation of fractional vegetation cover(FVC) is important for identifying and monitoring desertification, especially in arid and semiarid regions. By using regression and pixel dichotomy models, we present the comparison of Sentinel-2A(S2) multispectral instrument(MSI) and Landsat 8(L8) operational land imager(OLI) data regarding the retrieval of FVC in a semi-arid sandy area(Mu Us Sandland, China, in August 2016). A combination of unmanned aerial vehicle(UAV) high-spatial-resolution images and field plots were used to produce verified data. Based on a normalized difference vegetation index(NDVI) regression model, the results showed that, compared with that of L8, the coefficient of determination(R2) of S2 increased by 26.0%, and the root mean square error(RMSE) and the sum of absolute error(SAE) decreased by 3.0% and 11.4%, respectively. For the ratio vegetation index(RVI) regression model, compared with that of L8, the R2 of S2 increased by 26.0%, and the RMSE and SAE decreased by 8.0% and 20.0%, respectively. When the pixel dichotomy model was used, compared with that of L8, the RMSE of S2 decreased by 21.3%, and the SAE decreased by 26.9%. Overall, S2 performed better than L8 in terms of FVC inversion. Additionally, in this paper, we develop a verified scheme based on UAV data in combination with the object-based classification method. This scheme is feasible and sufficiently robust for building relationships between field data and inversion results from satellite data. Further, the synergy of multi-source sensors(especially UAVs and satellites) is a potential effective way to estimate and evaluate regional ecological environmental parameters(FVC). | LIU Qiuyu ZHANG Tinglong LI Yizhe LI Ying BU Chongfeng ZHANG Qingfeng | 2019 | Chinese Geographical Science2019，29，1： | 4 |
| 2 | Physiological responses of artificial moss biocrusts to dehydration-rehydration process and heat stress on the Loess Plateau, China显示文摘Ex-situ cultivation of biological soil crusts(biocrusts) is a promising technology to produce materials that can induce the recovery of biocrusts in the field for the purposes of preventing soil erosion and improving hydrological function in degraded ecosystems. However, the ability of artificially cultivated biocrusts to survive under adverse field conditions, including drought and heat stresses, is still relatively unknown. Mosses can bolster biocrust resistance to the stresses(e.g., drought and heat) and the resistance may be introduced prior to field cultivation. In this study, we subjected the well-developed artificial moss biocrusts(dominant species of Didymodon vinealis(Brid.) Zand.) that we cultivated in the phytotron to a dehydration-rehydration experiment and also a heat stress experiment and measured the activities of protective enzymes(including peroxidase(POD), superoxide dismutase(SOD), and catalase(CAT)) and the contents of osmoregulatory substances(including soluble proteins and soluble sugars) and malondialdehyde(MDA, an indicator of oxidative stress) in the stem and leaf fragments of mosses. The results showed that, during the dehydration process, the activities of protective enzymes and the contents of osmoregulatory substances and MDA gradually increased with increasing duration of drought stress(over 13 days). During the rehydration process, values of these parameters decreased rapidly after 1 d of rehydration. The values then showed a gradual decrease for 5 days, approaching to the control levels. Under heat stress(45°C), the activities of protective enzymes and the content of soluble proteins increased rapidly within 2 h of heat exposure and then decreased gradually with increasing duration of heat exposure. In contrast, the contents of soluble sugars and MDA always increased gradually with increasing duration of heat exposure. This study indicates that artificial moss biocrusts possess a strong drought resistance and this resistance can be enhanced after a gradual dehydration treatment. This study also indicates that artificial moss biocrusts can only resist short-term heat stress(not long-term heat stress). These findings suggest that short-term heat stress or prolonged drought stress could be used to elevate the resistance of artificial moss biocrusts to adverse conditions prior to field reintroduction. | BU Chongfeng WANG Chun YANG Yongsheng ZHANG Li Matthew A BOWKER | 2017 | Journal of Arid Land2017，9，3： | 4 |
| 3 | Rare Earth Luminescent Materials for White LED Solid State Lighting显示文摘Solid-state white LED will be a new generation of energy-saving light source in 21 century. In order to emitting white light, one of important approaches is using luminescence conversion technology with rare earth phosphors, which can be excited by the 460 nm blue light or 400 nm near violet light emitted from the InGaN chip and then emit white light. The rare earths doped phosphors prepared by us such as YAG∶Ce 3+, Ca 1-xSrxS∶Eu 2+, Ga2S3∶Eu 2+, MGa2S4∶Eu 2+(M=Ca, Sr, Ba), SrGa 2+xS 4+y∶Eu 2+, (Ca 1-xSrx)Se∶Eu 2+, SrLaGa3S6O∶Eu 2+, (M1, M2) 10(PO4)6X2 (M1=Ca, Sr, Ba; M2=Eu, Mn; X=F, Cl, Br) and NaEu 0.92Sm 0.08(MoO4)2 were reported. They emit blue, green, yellow or red color light. Some white LEDs were made by these phosphors with blue or near violet InGaN chips and their chromaticity coordinate (x, y), correlated color temperature TC, and color rendering index Ra are reported. | Su Qiang Wu Hao Pan Yuexiao Xu Jian Guo Chongfeng Zhang Xinmin Zhang Jianhui Wang Jing Zhang Mei | 2005 | Journal of Rare Earths2005，23，5： | 3 |
| 4 | Political connections, tax benefits and firm performance: Evidence from China显示文摘 | Wenfeng Wu Chongfeng Wu Chunyang Zhou Jun Wu | 2011 | Journal of Accounting and Public Policy2011，，3： | 2 |
| 5 | Is China's Economic Growth Extraordinary or Mediocre?The Role of the Exchange Rate显示文摘结果用不同措施源于评估因为中国的经济生长是分叉的,特别当 RMB 汇率经历了大跌价时。在匹配经济开发的要求的 RMB 汇率集中于变化,我们在评估结果为变化为一些提供貌似合理的解释。在在 mid-1990s 前的不同经济表演评估结果之间的重要差距,和从因素生产率的国际比较的证据显示在中国的经济生长的质量与另外的经济的不同。经济开发的评估应该考虑量的扩大和质的改进。从这个观点,评估结果在 mid-1990s 以后在中国经济显示质的改进。 | Yun Feng Chongfeng Wu | 2008 | China & World Economy2008，16，1： | 2 |
| 6 | Trade credit, cash holdings, and financial deepening: Evidence from a transitional economy显示文摘 | Wenfeng Wu Oliver M. Rui Chongfeng Wu | 2011 | Journal of Banking and Finance2011，，11： | 2 |
| 7 | 显示文摘 | Wu Hao Zhang Xinmin Guo Chongfeng | 2005 | IEEE Photonics Technology Letters2005，17，6： | 1 |
| 8 | 显示文摘 | Guo Chongfeng Huang Dexiu Su Qiang | 2006 | Materials Science and Engineering B2006，130，： | 1 |
| 9 | Methods to improve the fluorescence intensity of CaS : Eu^2+ red-emitting phosphor for white LED显示文摘 | Guo Chongfeng Huang Dexiu Su Qiang | 2006 | Mater Sci Eng B2006，130，13： | 1 |
| 10 | The influence of tertiary amine accelerators on the curing behaviors of epoxy/anhydride systems显示文摘 | Tao Yang Chongfeng Zhang Junying Zhang Jue Cheng | 2014 | Thermochimica Acta2014，，： | 1 |
| 11 | Preparation of Y 2 O 2 S:Eu 3+ phosphors by a novel decomposition method显示文摘 | Chongfeng Guo Lin Luan Changhong Chen Dexiu Huang Qiang Su | 2007 | Materials Letters2007，，4： | 1 |
| 12 | Spatio- temporal dynamics of urban forest conversion through model urbanization in Shenzhen, China显示文摘 | GONG Chongfeng CHEN Jiquan YU Shixiao | 2011 | International Journal of Remote Sensing2011，32，： | 1 |
| 13 | Preparation of stable CaS: Eu^2+ ,Tm^3+ phosphor显示文摘 | Guo Chongfeng Chu Benli Wu Mingmei | 2003 | J Rare Earths2003，21，5： | 1 |
| 14 | Oxide coating for alkaline earth sulfide based phosphor 显示文摘 | Guo Chongfeng Chu Benli Wu Mingmei | 2003 | J Luminescesce2003，105，： | 1 |
| 15 | Improving the stability of alkaline earth sulfide - based phosphors显示文摘 | Guo Chongfeng Chu Benli Su Qiang | 2004 | Applied Surface Science2004，225，14： | 1 |
| 16 | White-emitting phosphor Ca2BO3Cl:Cea+ , Eu2+ for UV light-emitting diodes 显示文摘 | Guo Chongfeng Lin Luan Frank G Shi | 2009 | Journal of the electrochemical society2009，156，6： | 1 |
| 17 | Luminescent properties of Eu^2+ and Ho^3+ co- doped CaGa2S4 phosphor显示文摘 | Guo Chongfeng Zhang Chunxiang Lu Yuhua | 2004 | Phys Stat Sol(a)2004，201，7： | 1 |
| 18 | White light genera- tion phosphor Ba2 Ca(BO3 ) 2 : Ce3 + , Mn2+ for light-emitting di- odes显示文摘 | Guo Chongfeng Luan Lin Xu Yan | 2008 | Journal of the Electrochemical Society2008，155，11： | 1 |
| 19 | J Electrochem Soc显示文摘 | Guo Chongfeng Luan Lin Xu Yan | 2008 | 155(11): 3102008，155，11： | 1 |
| 20 | Optical thermometry based on the upconversion fluorescence from Yb 3+ /Er 3+ codoped La 2 O 2 S phosphor显示文摘 | Yanmin Yang Chao Mi Fang Yu Xianyuan Su Chongfeng Guo Gang Li Jiao Zhang Linlin Liu Yanzhou Liu Xiaodong Li | 2014 | Ceramics International2014，，： | 1 |
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