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| 1 | Feature analysis of LIDAR waveforms from forest canopies显示文摘Airborne light detection and ranging (LIDAR) can detect the three-dimensional structure of forest canopies by transmitting laser pulses and receiving returned waveforms which contain backscatter from branches and leaves at different heights.We established a solid scatterer model to explain the widened durations found in analyzing the relationship between laser pulses and forest canopies,and obtained the corresponding rule between laser pulse duration and scatterer depth.Based on returned waveform characteristics,scatterers were classified into three types:simple,solid and complex.We developed single-peak derivative and multiple-peak derivative analysis methods to retrieve waveform features and discriminate between scatterer types.Solid scatterer simulations showed that the returned waveforms were widened as scatterer depth increased,and as space between sub-scatterers increased the returned waveforms developed two peaks which subsequently developed into two separate sub-waveforms.There were slight differences between the durations of simulated and measured waveforms.LIDAR waveform data are able to describe the backscatter characteristics of forest canopies,and have potential to improve the estimation accuracy of forest parameters. | LIU QingWang LI ZengYuan CHEN ErXue PANG Yong LI ShiMing TIAN Xin | 2011 | Science China Earth Sciences2011，54，8： | 6 |
| 2 | Amniotic Membrane Transplantation for Conjunctival Tumor显示文摘Purpose: To evaluate the possibility of amniotic membrane transplantation (AMT) for the treatment of conjunctival tumor.Methods: Preserved AMT was performed in 26 patients (26 eyes) with conjunctival tumor, including 9 eyes (34.62%) with malignant tumor (conjunctival malignant melanoma,corneal and conjunctival squamous cell carcinoma, conjunctival lymphoma), 17 eyes(65.38%) with benign tumor(conjunctival papilloma, conjunctival dermoid tumor, conjunctival nevus, hemangioma etc.).Result: All the patients are followed up for 1 ~53 months. No acute rejection was observed after preserved AMT. Ideal healing was found in conjunctiva wound.Conclusion: Preserved AMT is a very effective method to repair wound after giant conjunctival tumor operation. Complete removal of tumor and perfect fixation are the key of ocular surface reconstruction. | Zhicong Chen, Jianhua Yan, Huasheng Yang, Zhongyao Wu Youjian Pang, Shiming Ai, Yuxiang Mao Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China | 2003 | Eye Science2003，19，3： | 2 |
| 3 | A tandem asymmetric oxidation-oxa-Michael sequence for dearomatization ofβ-naphthols显示文摘A catalytic asymmetric hydroxylative dearomatization reaction has been disclosed,and the products can smoothly transform into spiroannulation adducts by simply treated with a base under mild conditions.Novel in-situ generated magnesium catalytic methods are developed by application of combinational ligands.Related concise transformaitons of the spiroannulation adducts have been carried out. | Linqing Wang Haiyong Zhu Tianyu Peng Yingfan Xu Yanzhe Hou Shixin Li Shiming Pang Hailong Zhang Dongxu Yang | 2022 | Chinese Chemical Letters2022，33，9： | 0 |
| 4 | Assessing spatiotemporal variations of forest carbon density using bi-temporal discrete aerial laser scanning data in Chinese boreal forests显示文摘Assessing the changes in forest carbon stocks over time is critical for monitoring carbon dynamics,estimating the balance between carbon uptake and release from forests,and providing key insights into climate change mitigation.In this study,we quantitatively characterized spatiotemporal variations in aboveground carbon density(ACD)in boreal natural forests in the Greater Khingan Mountains(GKM)region using bi-temporal discrete aerial laser scanning(ALS)data acquired in 2012 and 2016.Moreover,we evaluated the transferability of the proposed design model using forest field plot data and produced a wall-to-wall map of ACD changes for the entire study area from 2012 to 2016 at a grid size of 30 m.In addition,we investigated the relationships between carbon dynamics and the dominant tree species,age groups,and topography of undisturbed forested areas to better understand ACD variations by employing heterogeneous forest canopy structural characteristics.The results showed that the performance of the temporally transferable model(R^(2)=0.87,rRMSE=18.25%),which included stable variables,was statistically equivalent to that obtained from the model fitted directly by the 2016 field plots(R^(2)=0.87,rRMSE=17.47%).The average rate of change in carbon sequestration across the entire study region was 1.35 Mg⋅ha^(-1)⋅year^(-1) based on the changes in ALS-based ACD values over the course of four years.The relative change rates of ACD decreased as the elevation increased,with the highest and lowest ACD growth rates occurring in the middle-aged and mature forest stands,respectively.The Gini coefficient,which represents forest canopy surface structure heterogeneity,is sensitive to carbon dynamics and is a reliable predictor of the relative change rate of ACD.This study demonstrated the applicability of bi-temporal ALS for predicting forest carbon dynamics and fine-scale spatial change patterns.Our research contributed to a better understanding of the in-fluence of remote sensing-derived environmental variables on forest carbon dynamic patterns and the development of context-specific management approaches to increase forest carbon stocks. | Zhiyong Qi Shiming Li Yong Pang Guang Zheng Dan Kong Zengyuan Li | 2023 | Forest Ecosystems2023，10，5： | 0 |
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