Rooftop greening not only has ecological benefits such as energy savings, water conservation and air quality improvement but also has aesthetic and social benefits, especially for the rooftops of commercial complexes,...Rooftop greening not only has ecological benefits such as energy savings, water conservation and air quality improvement but also has aesthetic and social benefits, especially for the rooftops of commercial complexes, which should meet people’s demand for beauty while satisfying sustainable urban development. In this paper, 80 samples of ten commercial rooftops in five old urban areas of Chengdu, China, were selected as the research objects, and the beauty values of different roof types and different plant community types were quantified by the aesthetic evaluation method, and the factors influencing the beauty values were investigated. The results showed that the highest average SBE value was for plant ornamental roofs (0.635), followed by recreational roofs (0.080), and the lowest average SBE value was for sports and fitness (-0.555);Mixed needle-broad communities had the greatest average SBE value (0.330), followed by mixed bamboo-broad communities (0.094), while pure bamboo forests had the lowest average SBE value (-0.716). The rooftop plant community’s aesthetic value was highly significant and correlated positively with the type of roof, the community’s growth type, its vertical structure, and the number of plants in the community.展开更多
Global warming has led to the frequent occurrence of extreme climatic events(ECEs)in the ecologically frag ile Qinghai-Xizang Plateau.Rural households face strong barriers in adaption,and food production is seriously ...Global warming has led to the frequent occurrence of extreme climatic events(ECEs)in the ecologically frag ile Qinghai-Xizang Plateau.Rural households face strong barriers in adaption,and food production is seriously threatened.Current methods for increasing household adaptability take a holistic point of view,but do not ac curately identify groups experiencing different adaptive barriers.To better identify different barriers,this paper examines natural,economic,cognitive,and technical barriers.A total of 17 indicators were selected to com prehensively evaluate the degree of barriers to crops adaptation in response to ECEs.Key factors were further analyzed to identify paths to break down the barriers.The results showed the following.(1)Natural barriers were present at the highest degree,economic barriers appear to be smallest,and the overall barriers were bi ased towards the lower quartile.10.82%of the households with the highest barriers.(2)67.38%of households report taking adaptive measures in crops production.The increase of the barriers leads to an increase and then a decrease in the possibility of adaptive behavior.(3)Addressing technical barriers is key to rapidly increasing household adaptive behavior in response to ECEs.The study provides recommendations for local governments to improve household adaptation behavior from two perspectives:short-term and long-term optimization path ways.This study can help governments quickly locate households with different classes of barriers,and propose more targeted adaptation policies.The ultimate goal is to ensure the sustainability of crops production and the well-being of households in northeastern part of the Qinghai-Xizang Plateau.展开更多
Lacquer is the main raw material of lacquerware,while UV-irradiation is an important factor leading to its aging.In order to investigate the aging behavior of urushi lacquer film under UV-irradiation,and to propose pa...Lacquer is the main raw material of lacquerware,while UV-irradiation is an important factor leading to its aging.In order to investigate the aging behavior of urushi lacquer film under UV-irradiation,and to propose parameters that can be used to evaluate its aging degree,the micro-UV/Py-GC/MS system has been applied in the present work to enrich and identify volatile products released by urushi film during aging on the one hand,and to investigate micro-amount and conventional urushi films with different aging degrees on the other hand,in addition,representative historical samples have also been investigated.Volatile products released by urushi film demonstrate that during UV-irradiation,polysaccharides wrapping urushiol polymer would be first degraded to generate furans and alcohols,and then urushiol polymer would undergo photo-oxidation and break of molecular chain,mainly generating oxidation products including aldehydes,organic acids,and ketones,as well as a small number of alkyl benzenes and hydrocarbons.Py-GC/MS analysis of micro-amount urushi films with different aging degrees indicates that UVirradiation is more destructive to aliphatic chains in urushiol polymer,but it also can accelerate the polymerization of microamount urushi film.Py-GC/MS analysis of conventional urushi films indicates that with the increase of aging degree,the total chromatographic peak area ratio of hydrocarbons to benzene derivatives gradually increases,the peak area ratio of 3-pentadecenyl-catechol to 3-pentadecyl-catechol gradually decreases,and the peak area ratio of aging products of urushiol to 3-pentadecyl-catechol gradually increases.The above parameters were further used to evaluate the aging degree of two urushicontained samples separately collected from the surface and interior of a carved lacquer panel in the Forbidden City,and evaluation results are in accord with the natural aging law and further verify the reliability of the proposed parameters.Research results of the present work can lay a foundation for the in-depth study of the UV-irradiation aging mechanism of urushi.展开更多
文摘Rooftop greening not only has ecological benefits such as energy savings, water conservation and air quality improvement but also has aesthetic and social benefits, especially for the rooftops of commercial complexes, which should meet people’s demand for beauty while satisfying sustainable urban development. In this paper, 80 samples of ten commercial rooftops in five old urban areas of Chengdu, China, were selected as the research objects, and the beauty values of different roof types and different plant community types were quantified by the aesthetic evaluation method, and the factors influencing the beauty values were investigated. The results showed that the highest average SBE value was for plant ornamental roofs (0.635), followed by recreational roofs (0.080), and the lowest average SBE value was for sports and fitness (-0.555);Mixed needle-broad communities had the greatest average SBE value (0.330), followed by mixed bamboo-broad communities (0.094), while pure bamboo forests had the lowest average SBE value (-0.716). The rooftop plant community’s aesthetic value was highly significant and correlated positively with the type of roof, the community’s growth type, its vertical structure, and the number of plants in the community.
基金supported by the Second Scientific Expedition to the Qinghai‒Xizang Plateau(Grant No.2019QZKK0405-05)method-ological support from the State Key Program of the National Natural Science Foundation of China(Grant No.72033005)is also appreciated greatly.
文摘Global warming has led to the frequent occurrence of extreme climatic events(ECEs)in the ecologically frag ile Qinghai-Xizang Plateau.Rural households face strong barriers in adaption,and food production is seriously threatened.Current methods for increasing household adaptability take a holistic point of view,but do not ac curately identify groups experiencing different adaptive barriers.To better identify different barriers,this paper examines natural,economic,cognitive,and technical barriers.A total of 17 indicators were selected to com prehensively evaluate the degree of barriers to crops adaptation in response to ECEs.Key factors were further analyzed to identify paths to break down the barriers.The results showed the following.(1)Natural barriers were present at the highest degree,economic barriers appear to be smallest,and the overall barriers were bi ased towards the lower quartile.10.82%of the households with the highest barriers.(2)67.38%of households report taking adaptive measures in crops production.The increase of the barriers leads to an increase and then a decrease in the possibility of adaptive behavior.(3)Addressing technical barriers is key to rapidly increasing household adaptive behavior in response to ECEs.The study provides recommendations for local governments to improve household adaptation behavior from two perspectives:short-term and long-term optimization path ways.This study can help governments quickly locate households with different classes of barriers,and propose more targeted adaptation policies.The ultimate goal is to ensure the sustainability of crops production and the well-being of households in northeastern part of the Qinghai-Xizang Plateau.
基金supported by the National Natural Science Foundation of China(Grant No.21904024)。
文摘Lacquer is the main raw material of lacquerware,while UV-irradiation is an important factor leading to its aging.In order to investigate the aging behavior of urushi lacquer film under UV-irradiation,and to propose parameters that can be used to evaluate its aging degree,the micro-UV/Py-GC/MS system has been applied in the present work to enrich and identify volatile products released by urushi film during aging on the one hand,and to investigate micro-amount and conventional urushi films with different aging degrees on the other hand,in addition,representative historical samples have also been investigated.Volatile products released by urushi film demonstrate that during UV-irradiation,polysaccharides wrapping urushiol polymer would be first degraded to generate furans and alcohols,and then urushiol polymer would undergo photo-oxidation and break of molecular chain,mainly generating oxidation products including aldehydes,organic acids,and ketones,as well as a small number of alkyl benzenes and hydrocarbons.Py-GC/MS analysis of micro-amount urushi films with different aging degrees indicates that UVirradiation is more destructive to aliphatic chains in urushiol polymer,but it also can accelerate the polymerization of microamount urushi film.Py-GC/MS analysis of conventional urushi films indicates that with the increase of aging degree,the total chromatographic peak area ratio of hydrocarbons to benzene derivatives gradually increases,the peak area ratio of 3-pentadecenyl-catechol to 3-pentadecyl-catechol gradually decreases,and the peak area ratio of aging products of urushiol to 3-pentadecyl-catechol gradually increases.The above parameters were further used to evaluate the aging degree of two urushicontained samples separately collected from the surface and interior of a carved lacquer panel in the Forbidden City,and evaluation results are in accord with the natural aging law and further verify the reliability of the proposed parameters.Research results of the present work can lay a foundation for the in-depth study of the UV-irradiation aging mechanism of urushi.
