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| 1 | Study on Ecological Risk of Land Use in Urbanization Watershed Based on RS and GIS:A Case Study of Songhua River Watershed in Harbin Section显示文摘By using RS and GIS technology,the ecological risk index ( ERI) was constructed based on the analysis of land use change and structural characteristics in urbanization watershed of Songhua River in Harbin section. Afterwards,the spatial distribution and change characteristics maps of ERI obtained by using block Kriging were analyzed to reveal the spatial and temporal evolution characteristics,change rules and formation mechanisms of ecological risk based on land use under the background of urbanization,and to minimize land use risk during urbanization process. The results showed that during the past 18 years,moderate ecological risk level was major,while proportion of high ecological risk was the lowest,and the area of higher and lower ecological risk region changed most greatly; high and higher ecological risk were focused on urban region and the transition zone from urban to suburban region,while low and lower ecological risk mainly distributed in forestland with higher vegetation coverage,water bodies,grassland,shrub land and so on. Meanwhile,the transition zone from high to low ecological risk was very obvious. In addition,ecological risk became slightly worse in some region due to the transformation from cropland to residential and urban land,while it became slightly better in other regions because of the transformation from cropland to forestland; the center of gravity in lower ecological risk region shifted most greatly,while the shift was the smallest in high ecological risk region,namely 12. 31 and 0. 57 km respectively. | Li YUAN Wenfeng GONG Yongfeng DANG Zexu LONG | 2013 | Asian Agricultural Research2013,5,3: | 7 |
| 2 | Effect of TiO_2@SiO_2 nanoparticles on the mechanical and UV-resistance properties of polyphenylene sulfide fibers显示文摘In order to avoid the inherent photo-catalysis and aggregation of TiO2 in PPS, TiO2 nanoparticles were coated with SiO2 layers, which were chosen as the UV absorbent to improve the UV stability of polyphenylene sul fi de(PPS) fi ber. The PPS–TiO2@SiO2 nanocomposites fi bers were prepared via melt spinning, and the nanocomposites fi bers displayed different crystallization behaviors on variation of the diameters of TiO2@SiO2 nanoparticles, as con fi rmed by Differential Scanning Calorimetry(DSC). The spinnability, breaking strength and UV-resistance properties of PPS nanocomposites fi bers, as measured by homemade melt spinning machine, Xenon-lamp Weather Resistance Test Chamber and Yarn Tensile Tester, manifested the dependence on the diameters. The addition of nanoparticles with the diameter of 25 nm improved the spinnability and the mechanical performance of PPS most, which is attributed to the heterogeneous nucleation effect of nanoparticles. The UVresistance properties of the PPS nanocomposites were improved by the addition of TiO2@SiO2 nanoparticles. After aging for 180 h, PPS nanocomposites fi ber still maintained a high strength. | Zexu Hu Lili Li Bin Sun Si Meng Long Chen Meifang Zhu | 2015 | Progress in Natural Science:Materials International2015,25,4: | 5 |
| 3 | Large-area perovskite films for PV applications:A perspective from nucleation and crystallization显示文摘Perovskite solar cells(PSCs)have attracted significant research interest due to the rapid rise in efficiency.However,a large efficiency gap still exists between laboratory-based small devices and industrialoriented large-scale modules.One of the main reasons for the efficiency losses is the degraded quality and morphology of the deposited large-area films,which is closely associated with crystallization processes.In this review,we discuss the nucleation and crystallization processes in solution and vaporbased up-scaling deposition methods for large-area perovskite films.We review recent scientific achievements and technical developments that have been made in the field of large-area cells.We present the existing problems that limit the performance of large devices and extensively discuss the key influencing parameters from the perspective of nucleation and crystallization over large areas.This review highlights the importance of crystallization control in up-scaling fabrications and presents promising strategies towards large-area perovskite-based optoelectronic devices. | Yuanhang Yang Zexu Xue Long Chen Cho Fai Jonathan Lau Zhiping Wang | 2021 | Journal of Energy Chemistry2021,30,8: | 0 |
| 4 | A Review of the Engineering Role of Burrowing Animals: Implication of Chinese Pangolin as an Ecosystem Engineer显示文摘Ecosystem engineers are organisms that alter the distribution of resources in the environment by creating,modifying,maintaining and/or destroying the habitat.They can affect the structure and function of the whole ecosystem furthermore.Burrowing engineers are an important group in ecosystem engineers as they play a critical role in soil translocation and habitat creation in various types of environment.However,few researchers have systematically summarized and analyzed the studies of burrowing engineers.We reviewing the existing ecological studies of burrowing engineer about their interaction with habitat through five directions:(1)soil turnover;(2)changing soil physicochemical properties;(3)changing plant community structure;(4)providing limited resources for commensal animals;and/or(5)affecting animal communities.The Chinese pangolin(Manis pentadactyla)is a typical example of burrowing mammals,in part(5),we focus on the interspecific relationships among burrow commensal species of Chinese pangolin.The engineering effects vary with environmental gradient,literature indicates that burrowing engineer play a stronger role in habitat transformation in the tropical and subtropical areas.The most common experiment method is comparative measurements(include different spatial and temporal scale),manipulative experiment is relatively few.We found that most of the engineering effects had positive feedback to the local ecosystem,increased plant abundance and resilience,increased biodiversity and consequently improved ecosystem functioning.With the global background of dramatic climate change and biodiversity loss in recent decades,we recommend future studies should improving knowledge of long-term engineering effects on population scale and landscape scale,exploring ecological cascades through trophic and engineering pathways,to better understand the attribute of the burrowing behavior of engineers to restore ecosystems and habitat creation.The review is presented as an aid to systematically expound the engineering effect of burrowing animals in the ecosystem,and provided new ideas and advice for planning and implementing conservation management. | Song Sun Hongliang Dou Shichao Wei Yani Fang Zexu Long Jiao Wang Fuyu An Jinqian Xu Tingting Xue Huangjie Qiu Yan Hua Guangshun Jiang | 2021 | Journal of Zoological Research2021,3,3: | 0 |