排序方式: 共有4条查询结果,搜索用时 46 毫秒
1
1.
The catalytic activity of Pd catalysts supported on Ce0.73Tb0.27Ox/SiO2, Ce0.6Zr0.4Ox/SiO2, Ce0.73Tb0.27Ox/La2O3-Al2O3 and Ce0.6Zr0.4Ox/La2O3-Al2O3 was studied using the reduction of NO by CO. The catalysts were characterized by X-ray fluorescence, surface area, X-ray diffraction, temperature-programmed reduction, CO chemisorption and oxygen storage capacity. Temperature-programmed reduction results indicated that Tb or Zr incorporation improves the reducibility and oxygen storage capacity. CO chemisorption data suggested the presence of large PdO particles due to the low CO/Pd ratio. No significant differences were obtained in light off temperatures (TLight off) for all Pd catalysts and the most active was 1.5%Pd/Ce0.6Zr0.4Ox/SiO2. 相似文献
2.
Stephen G. Perz Liliana Cabrera Lucas Araújo Carvalho Jorge Castillo Rosmery Chacacanta Rosa E. Cossio Yeni Franco Solano Jeffrey Hoelle Leonor Mercedes Perales Israel Puerta Daniel Rojas Céspedes Ioav Rojas Camacho Ad?o Costa Silva 《Regional Environmental Change》2012,12(1):35-53
Initiatives for global economic integration increasingly prioritize new infrastructure in relatively remote regions. Such regions have relatively intact ecosystems and provide valuable ecosystem services, which has stimulated debates over the wisdom of new infrastructure. Most prior research on infrastructure impacts highlights economic benefits, ecological damage, or social conflicts. We suggest a more integrative approach to regional integration by appropriating the concepts of connectivity from transport geography and social?Cecological resilience from systems ecology. Connectivity offers a means of observing the degree of integration between locations, and social?Cecological resilience provides a framework to simultaneously consider multiple consequences of regional integration. Together, they offer a spatial analysis of resilience that considers multiple dimensions of infrastructure impacts. Our study case is the southwestern Amazon, a highly biodiverse region which is experiencing integration via paving of the Inter-Oceanic Highway. Specifically, we focus on the ??MAP?? region, a tri-national frontier where Bolivia, Brazil, and Peru meet and which differs in the extent of highway paving. We draw on a tri-national survey of more than 100 resource-dependent rural communities across the MAP frontier and employ indicators for multiple dimensions of connectivity and social?Cecological resilience. We pursue a comparative analysis among regions and subregions with differing degrees of community connectivity to markets in order to evaluate their social?Cecological resilience. The findings indicate that connectivity and resilience have a multifaceted relationship, such that greater community connectivity corresponds to greater resilience in some respects but not others. We conclude by noting how our findings integrate those from heretofore largely disparate literatures on infrastructure. The integration of transport geography with resilience thought thus stands to advance the study of infrastructure impacts. 相似文献
3.
E. Salinas J. Atalaya Y. Hamnerius C. J. Solano D. Gonzales C. Contreras C. Leon M. A. Sumari S. Dimitriou M. Rezinkina 《The Environmentalist》2007,27(4):571-576
When large structures such as residential compounds or public buildings are under the influence of extremely low frequency
(ELF) magnetic fields, such as the one generated by a system of railways fed by 16.67 Hz, standard methods of designing shielding
structures by numerical methods usually fail. The latter can be explained by the difficulty posed in the computing process
by the large aspect ratios involved due to thin layers of metal (a few millimetres or centimetres) in contrast to the large
dimensions of the affected structure (several tens of meters). In some cases one has to utilize special approximations such
as surface conductivity, which are not easy to handle when the designed shielding structure is clearly three -dimensional.
Other alternatives such as experimentation in situ are very costly. Here, a new technique is presented of mitigating the field
by using three-dimensional propagation of induced currents optimizing the field reduction factors and minimizing the cost
of shielding material. The particular designing method is a hybrid of numerical simulations combined with lab experimentation
using scaled models of the large structure. The method is rather cost-effective and flexible as various designs can be easily
tested. Results are presented in the form of magnetic field values, at various locations in the buildings, before and after this mitigation technique is applied. 相似文献
4.
Solano Ricardo Patiño-Ruiz David Tejeda-Benitez Lesly Herrera Adriana 《Environmental science and pollution research international》2021,28(14):16962-16981
Environmental Science and Pollution Research - The production and demand of nanoparticles in the manufacturing sector and personal care products, release a large number of engineered nanoparticles... 相似文献
1