The morphologies of goethites in latosol, red soils, yellow-brown soil and the paddy soils developed from red soils were studied in comparison with the morphology of synthetic goethite by means of the X-ray distractio...The morphologies of goethites in latosol, red soils, yellow-brown soil and the paddy soils developed from red soils were studied in comparison with the morphology of synthetic goethite by means of the X-ray distraction, transmission electron microscopy and energy dispersive X-ray analysis. The synthetic goethite displayed acicular particles elongated in the c-direction. The goethites in the latosol, red soils and yellowbrown soil were platy particles stretched in two directions or isodimensional particles, and those in the paddy soils from red soils were acicular, short columnar, platy or isodimensional particles. Various morphologies of the goethites probably suggested their different dominant crystal faces, surface charge distribution and surface adsorption characteristics.展开更多
Soil respiration (SR) Wis one of the largest contributors of terrestrial CO_2 to the atmosphere.Environmental as well as physicochemical parameters influence SR and thus, different land use practices impact the emissi...Soil respiration (SR) Wis one of the largest contributors of terrestrial CO_2 to the atmosphere.Environmental as well as physicochemical parameters influence SR and thus, different land use practices impact the emissions of soil CO_2. In this study, we measured SR, bi-monthly, over a one-year period in a terrace tea plantation, a forest tea plantation and a secondary forest, in a subtropical mountain area in Xishuangbanna, China. Along with the measurement of SR rates, soil characteristics for each of the land use systems were investigated. Soil respiration rates in the different land use systems did not differ significantly during the dry season, ranging from2.7±0.2 μmol m^(-2) s^(-1) to 2.8±0.2 μmol m^(-2) s^(-1). During the wet season, however, SR rates were significantly larger in the terrace tea plantation(5.4±0.5 μmol m^(-2)s^(-1)) and secondary forest(4.9±0.4 μmol m^(-2)s^(-1)) than in the forest tea plantation(3.7±0.2 μmol m^(-2) s^(-1)).This resulted in significantly larger annual soil CO_2 emissions from the terrace tea and secondary forest,than from the forest tea plantation. It is likely that these differences in the SR rates are due to the 0.5times lower soil organic carbon concentrations in thetop mineral soil in the forest tea plantation, compared to the terrace tea plantation and secondary forest.Furthermore, we suggest that the lower sensitivity to temperature variation in the forest tea soil is a result of the lower soil organic carbon concentrations. The higher SR rates in the terrace tea plantation were partly due to weeding events, which caused CO_2 emission peaks that contributed almost 10% to the annual CO_2 flux. Our findings suggest that moving away from heavily managed tea plantations towards low-input forest tea can reduce the soil CO_2 emissions from these systems. However, our study is a casestudy and further investigations and upscaling are necessary to show if these findings hold true at a landscape level.展开更多
In China, REC （residential energy consumption） is the second largest energy use category （10%） following the industry. To fulfill the Chinese government＇s commitment that Chinese CO2 emissions would peak in 2030,...In China, REC （residential energy consumption） is the second largest energy use category （10%） following the industry. To fulfill the Chinese government＇s commitment that Chinese CO2 emissions would peak in 2030, as a result, improving the energy efficiency and reducing the emissions from the building sector is significantly important. A survey, in the form of a questionnaire, of energy consumption and thermal situation in different residential building types （detached house, multi-story building, high-rise building）, was undertaken in three cities （Shanghai, Hangzhou, and Changzhou） in hot-summer and cold-winter regions, these three cities were selected to represent the most flourishing economic provinces. This region in China was selected for the evaluation of EETP （energy and thermal performance analysis）, because of its special weather conditions, huge energy consumption （as both heating in winter and cooling in summer are necessary）, and other regional characteristics. 183 households were sampled and experiments were separately done in typical examples of three different building types. Systematic evaluation on EETP for three different residential building types, were put forward to assess the energy efficiency and thermal performance of three different building types.展开更多
This work presents an analysis for the rural vernacular dwelling （Culata Yovai）, sited in the South America Guarani region, basin of Paraguay and Paraná rivers. Outdoor climate has conducted man to build along ...This work presents an analysis for the rural vernacular dwelling （Culata Yovai）, sited in the South America Guarani region, basin of Paraguay and Paraná rivers. Outdoor climate has conducted man to build along the time a habitat climatic responsive. Nowadays, studies in progress try to show how this vernacular typology can support new low-income house designs. The intent is to guarantee for new projects the socio-cultural image that people, coming from countryside to live in city outskirts, are accostumed. Also, to provide material improvements and functional adequation for a quality and healthiness. Natural ventilation is the main bioclimatic strategy during summer for thermal comfort, which influences the house characteristics. This is proven by calculation, and simulation with the CFX-ANSYS software. Thus, the analysis performed shows the real possibity to reconcile bioclimatism with the symbolic-cultural value represented by this vernacular architecture form. It is hopped that this study can be considered as a methodological contributition for new sustainable projects （materials, technics and services） of low-incoming houses in this Latin American region.展开更多
The hypersonic long-run scramjet test tunnel is one of the key ground facilities for the studies of ramjet/scramjet and hypersonic thermal management.Due to the significantly large heat loading,the nozzle of the tunne...The hypersonic long-run scramjet test tunnel is one of the key ground facilities for the studies of ramjet/scramjet and hypersonic thermal management.Due to the significantly large heat loading,the nozzle of the tunnel facility demands effective cooling protection.In this work,the two-dimensional,three-dimensional and axisymmetric Mach 6.5 nozzles at an inlet total temperature of 1840 K and a total pressure of 6.4 MPa were studied with main focuses on the properties of aerodynamic heating of nozzles.The present work aims to provide insights into the design of an effective cooling system for the nozzle and other components of the hypersonic long-run wind tunnel.展开更多
文摘The morphologies of goethites in latosol, red soils, yellow-brown soil and the paddy soils developed from red soils were studied in comparison with the morphology of synthetic goethite by means of the X-ray distraction, transmission electron microscopy and energy dispersive X-ray analysis. The synthetic goethite displayed acicular particles elongated in the c-direction. The goethites in the latosol, red soils and yellowbrown soil were platy particles stretched in two directions or isodimensional particles, and those in the paddy soils from red soils were acicular, short columnar, platy or isodimensional particles. Various morphologies of the goethites probably suggested their different dominant crystal faces, surface charge distribution and surface adsorption characteristics.
基金financially supported by the Yunnan Department of Sciences and Technology of China (Grant No. 2012EB056)Further support was supplied by the CGIAR Research Program 6: Forests, Trees and Agroforestry
文摘Soil respiration (SR) Wis one of the largest contributors of terrestrial CO_2 to the atmosphere.Environmental as well as physicochemical parameters influence SR and thus, different land use practices impact the emissions of soil CO_2. In this study, we measured SR, bi-monthly, over a one-year period in a terrace tea plantation, a forest tea plantation and a secondary forest, in a subtropical mountain area in Xishuangbanna, China. Along with the measurement of SR rates, soil characteristics for each of the land use systems were investigated. Soil respiration rates in the different land use systems did not differ significantly during the dry season, ranging from2.7±0.2 μmol m^(-2) s^(-1) to 2.8±0.2 μmol m^(-2) s^(-1). During the wet season, however, SR rates were significantly larger in the terrace tea plantation(5.4±0.5 μmol m^(-2)s^(-1)) and secondary forest(4.9±0.4 μmol m^(-2)s^(-1)) than in the forest tea plantation(3.7±0.2 μmol m^(-2) s^(-1)).This resulted in significantly larger annual soil CO_2 emissions from the terrace tea and secondary forest,than from the forest tea plantation. It is likely that these differences in the SR rates are due to the 0.5times lower soil organic carbon concentrations in thetop mineral soil in the forest tea plantation, compared to the terrace tea plantation and secondary forest.Furthermore, we suggest that the lower sensitivity to temperature variation in the forest tea soil is a result of the lower soil organic carbon concentrations. The higher SR rates in the terrace tea plantation were partly due to weeding events, which caused CO_2 emission peaks that contributed almost 10% to the annual CO_2 flux. Our findings suggest that moving away from heavily managed tea plantations towards low-input forest tea can reduce the soil CO_2 emissions from these systems. However, our study is a casestudy and further investigations and upscaling are necessary to show if these findings hold true at a landscape level.
文摘In China, REC （residential energy consumption） is the second largest energy use category （10%） following the industry. To fulfill the Chinese government＇s commitment that Chinese CO2 emissions would peak in 2030, as a result, improving the energy efficiency and reducing the emissions from the building sector is significantly important. A survey, in the form of a questionnaire, of energy consumption and thermal situation in different residential building types （detached house, multi-story building, high-rise building）, was undertaken in three cities （Shanghai, Hangzhou, and Changzhou） in hot-summer and cold-winter regions, these three cities were selected to represent the most flourishing economic provinces. This region in China was selected for the evaluation of EETP （energy and thermal performance analysis）, because of its special weather conditions, huge energy consumption （as both heating in winter and cooling in summer are necessary）, and other regional characteristics. 183 households were sampled and experiments were separately done in typical examples of three different building types. Systematic evaluation on EETP for three different residential building types, were put forward to assess the energy efficiency and thermal performance of three different building types.
文摘This work presents an analysis for the rural vernacular dwelling （Culata Yovai）, sited in the South America Guarani region, basin of Paraguay and Paraná rivers. Outdoor climate has conducted man to build along the time a habitat climatic responsive. Nowadays, studies in progress try to show how this vernacular typology can support new low-income house designs. The intent is to guarantee for new projects the socio-cultural image that people, coming from countryside to live in city outskirts, are accostumed. Also, to provide material improvements and functional adequation for a quality and healthiness. Natural ventilation is the main bioclimatic strategy during summer for thermal comfort, which influences the house characteristics. This is proven by calculation, and simulation with the CFX-ANSYS software. Thus, the analysis performed shows the real possibity to reconcile bioclimatism with the symbolic-cultural value represented by this vernacular architecture form. It is hopped that this study can be considered as a methodological contributition for new sustainable projects （materials, technics and services） of low-incoming houses in this Latin American region.
基金supported by the National Natural Science Foundation of China(Grant Nos.11202218 and 11172309)
文摘The hypersonic long-run scramjet test tunnel is one of the key ground facilities for the studies of ramjet/scramjet and hypersonic thermal management.Due to the significantly large heat loading,the nozzle of the tunnel facility demands effective cooling protection.In this work,the two-dimensional,three-dimensional and axisymmetric Mach 6.5 nozzles at an inlet total temperature of 1840 K and a total pressure of 6.4 MPa were studied with main focuses on the properties of aerodynamic heating of nozzles.The present work aims to provide insights into the design of an effective cooling system for the nozzle and other components of the hypersonic long-run wind tunnel.
