After the world climate change conference convened in Copenhagen, the idea of low-carbon has been widely accepted in the world and the low-carbon landscape is becoming the main trend of landscape design. The concept, principle and method of design of low-carbon landscape have been discussed from the idea of low-carbon in this paper, and a basis for future low-carbon landscape design has been provided.
The porous zirconia powder with a high surface area was synthesized by means of the ion exchange method from surfactant CTMAB. The highest surface area of the resulted zirconia reached 340 m2/g having been calcined at 500 ℃ for 2 h. The influence of preparing conditions on the surface area was investigated. The results show that the amount of the surfactant and the aging time were two main factors affecting the surface area of zirconia. The IR analysis indicated that the large surface area was related to the cations of the surfactant which incorporated into hydrous zirconia by ion exchange.
Radio frequency interference(RFI) is becoming more and more frequently, which makes it an important issue in SAR imaging.RFI presented in synthetic aperture radar either on purpose or inadvertent will distort the useful SAR echoes, thus degrade the SAR image quality.To resolve this issue, a long time study was carried out to study the characteristic of the RFI through the RFIaffected spaceborne and airborne SAR data.Based on the narrow band nature of RFI, this paper proposes a new process which contains both RFI detection and RFI suppression.A useful subband spectral kurtosis detector is first used to detect RFI, and then its results are used for RFI suppression.The proposed process has two advantages: one is the economization on the compute time for unnecessary interference suppression when no RFI existed; the other is improving the performance of the suppression method with knowing the exact position where RFI is.Moreover, the previous RFI suppression method––subband spectral cancelation(SSC) is supplemented and perfected.The subband division step is also elaborated detail in this paper.The experiment results show that the subband spectral kurtosis detector exhibits good performance in recognizing both weak and narrow-band RFI.In addition, the validity of the SSC method with subband spectral kurtosis detector is also validated on the real SAR echoes.
Winter wheat freeze injury is one of the main agro-meteorological disasters affecting wheat production. In order to evaluate the severity of freeze injury on winter wheat systematically, we proposed a grey-system model (GSM) to monitor the degree and the distribution of the winter wheat freeze injury. The model combines remote sensing (RS) and geographic information system (GIS) technology. It gave examples of wheat freeze injury monitoring applications in Gaocheng and Jinzhou of Hebei Province, China. We carried out a quantitative evaluation method study on the severity of winter wheat freeze injury. First, a grey relational analysis (GRA) was conducted. At the same time, the weights of the stressful factors were determined. Then a wheat freezing injury stress multiple factor spatial matrix was constructed using spatial interpolation technology. Finally, a winter wheat freeze damage evaluation model was established through grey clustering algorithm (GCA), and classifying the study area into three sub-areas, affected by severe, medium or light disasters. The evaluation model were verified by the Kappa model, the overall accuracy reached 78.82% and the Kappa coefficient was 0.6754. Therefore, through integration of GSM with RS images as well as GIS analysis, quantitative evaluation and study of winter wheat freeze disasters can be conducted objectively and accurately, making the evaluation model more scientific.
The mechanical performance of carbon nanotube(CNT) reinforced polymer composites is primarily controlled by the dispersive capacity and interfacial shear strength of CNTs in polymer matrices. CNT functionalizations will improve dispersion and strengthen interfacial bonding of CNTs in matrices. To understand the effects of different functionalization schemes on the interfacial strength of CNT-polymer composites, pullout of the covalent, noncovalent, and mixed functionalized single-walled carbon nanotube(SWCNT) from polyethylene(PE) matrix was simulated by using molecular dynamics, respectively. The results show that the SWCNT-PE interfacial shear strength is significantly improved by SWCNT functionalizations, particularly by mixed functionalization.
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