75 resultados para Built heritage sites


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Huazhong Univ Sci & Technol, Natl Tech Univ Ukraine, Huazhong Normal Univ, Harbin Inst Technol, IEEE Ukraine Sect, I& M/CI Joint Chapter

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Reducing uncertainties in the estimation of land surface evapotranspiration (ET) from remote-sensing data is essential to better understand earth-atmosphere interactions. This paper demonstrates the applicability of temperature-vegetation index triangle (T-s-VI) method in estimating regional ET and evaporative fraction (EF, defined as the ratio of latent heat flux to surface available energy) from MODIS/Terra and MODIS/Aqua products in a semiarid region. We have compared the satellite-based estimates of ET and EF with eddy covariance measurements made over 4 years at two semiarid grassland sites: Audubon Ranch (AR) and Kendall Grassland (KG). The lack of closure in the eddy covariance measured surface energy components is shown to be more serious at MODIS/Aqua overpass time than that at MODIS/Terra overpass time for both AR and KG sites. The T-s-VI-derived EF could reproduce in situ EF reasonably well with BIAS and root-mean-square difference (RMSD) of less than 0.07 and 0.13, respectively. Surface net radiation has been shown to be systematically overestimated by as large as about 60 W/m(2). Satisfactory validation results of the T-s-VI-derived sensible and latent heat fluxes have been obtained with RMSD within 54 W/m(2). The simplicity and yet easy use of the T-s-VI triangle method show a great potential in estimating regional ET with highly acceptable accuracy that is of critical significance in better understanding water and energy budgets on the Earth. Nevertheless, more validation work should be carried out over various climatic regions and under other different land use/land cover conditions in the future.

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Traditional agricultural systems are threatened world-wide mainly due to the introduction of modern agricultural techniques and the emigration of farm labourers from remote rural villages. The objective of the programme 'Globally Important Agricultural Heritage Systems' (GIAHS), initiated by the Food and Agriculture Organization (FAO) of the United Nations in 2002, is dynamic conservation of traditional agricultural systems. This article addresses the definition and content of agricultural heritage systems and discusses conservation options in the light of developing rural tourism. An explorative survey was conducted in Longxian village, situated in Zhejiang Province, southern China, focusing on the tourism potential of a typical Rice-Fish Agricultural System. The identification of heritage resources is a first step in the process of transforming an agricultural landscape into a cultural tourism landscape. However, the future of these landscapes is in the hands of a range of stakeholders and depends on their capacity to manage, in a sustainable way, tourism development strategies alongside conservation policies.

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Functionalized multiwalled carbon nanotubes (MWNTs) were selected as cross-linkers to construct three-dimensional (3D) porous nanoparticle/MWNT hybrid nanostructures by "bottom-up'' self-assembly. The resultant 3D hybrid nanostructure was different from that of metal nanoparticle multilayer assemblies prepared by traditional routes using small molecules or polymers as cross-linkers. The rigidity of the MWNTs resulted in only partial coverage of the nanoparticle surfaces between the linkers during the growth of multilayer film, providing more accessible surfaces to allow target molecules to adsorb on to and react with. HRP was used as a simple model to study the porosity of this assembly.

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Two novel coordination polymers Ni-4(CH3O)(4)(CH3OH)(4)(dca)(4) (1) and Co-4(CH3O)(4)(CH3OH)(4)(dca)(4) (2) have been synthesized by solvethermal reaction. X-ray single-crystal analysis reveals that the two complexes are isostrutural and possess 3D frameworks that are built from the M4O4(M= Ni (1) and Co (2)) cubanelike building blocks linked by dicyanamide (dca) bridges. The temperature dependence of the magnetic susceptibility was measured and the DC experiment data were fitted using the Heisenberg spin Hamiltonian.

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The low energy collision-induced dissociation, linked scan techniques and isotopic labeling experiment were used to investigate the unimolecular fragmentation of protonated N-hydroxyphthalimide under electron impact and chemical ionization conditions. It was found that this compound shows an unusual reactivity towards protonation. Two possible sites of protonation have been proposed to explain the corresponding fragmentation processes, one is that the protonation takes place on the oxygen atom of hydroxyl group, resulting in the loss of water and the other is the formation of an intermediary proton-bound complex in the fragmentation process, giving rise to the fragment ions of m/z 133 and m/z 135. The results show both cases are coexistence in the fragmentations of protonated N-hydroxyphthalimide, and the unimolecular fragmentation pathways are available.

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It was discovered experimentally that heteropolymolybdophosphoric acids (HPA) with Keggin and Dawson structure are inactive for H2O2-decomposition, while their salts (Fe3+, Cu2+, Co2+ and Mn2+) all possess more activity. It could be concluded that the act

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With the method of high temperature solid state reaction and stockbarger, we synthesized a series of powder phosphors of KMgF3-Ce3+, KMg1-alphaMalphaF3-Ce3+(M = Be2+, Ca2+) and the single crystal of KMgF3-Ce3+. We tested their excitation and emission spectra, found two emission centers in KMgF3-Ce3+ and demonstrated that they resulted from different charge compensating ways. By the structural analysis on KMgF3-Ce-3+ from a four-cycle diffractometer and spectral analysis on KMg1-alphaMalphaF3-Ce3+(M = Be2+, Ca2+), we deduced that Ce3+ ion only.substituted K+ site in KMgF3.

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To investigate the effects of enhanced nutrient loading in estuarine waters on phytoplankton growth and microzooplankton grazing, we conducted monthly dilution experiments at 2 stations in Hong Kong coastal waters with contrasting trophic conditions. The western estuarine station (WE) near the Pearl River estuary is strongly influenced by freshwater discharge, while the eastern oceanic station (EO) is mostly affected by the South China Sea. Growth rates of phytoplankton were often limited by nutrients at EO, while nutrient limitation of phytoplankton growth seldom Occurred at WE due to the high level of nutrients delivered by the Pearl River, especially in the summer rainy season. Higher chlorophyll a, microzooplankton biomass, phytoplankton growth and microzooplankton grazing rates were found at WE than at EO. However, the increase in chlorophyll greatly exceeded the increase in phytoplankton growth rate, reflecting different response relationships to nutrient availability. Strong seasonality was observed at both stations, with temperature being an important factor affecting both phytoplankton growth and microzooplankton grazing rates. Picophytoplankton, especially Synechococcus, also exhibited great seasonality at EO, with summer abundances being 2 or 3 orders of magnitude higher than those during winter, Our results confirm that in eutrophic coastal environments, microzooplankton grazing is a dominant loss pathway for phytoplankton, accounting for the utilization of >50%, of primary production on average.