In the study, waterfront street in Honggutan was researched by field investigation and questionnaire survey from space, transport, scale and human activity. The waterfront street has the following characters： ambiguo...In the study, waterfront street in Honggutan was researched by field investigation and questionnaire survey from space, transport, scale and human activity. The waterfront street has the following characters： ambiguous spatial structure, a lack of spatial design; a lack of business diversity, and over-scaled street space. The scale of waterfront space is amenity, diversified and hydrophilic property. We analyzed and performed a parallel comparison on waterfront street space to help improve Honggutan waterfront street by analyzing its design principles, and taking references from outstanding cases at home and abroad.展开更多
The indirect boundary element method(IBEM) was established to solve the problem of 3-D seismic responses of 2-D topographies,by calculating the free-field responses with the direct-stiffness method and simulating the ...The indirect boundary element method(IBEM) was established to solve the problem of 3-D seismic responses of 2-D topographies,by calculating the free-field responses with the direct-stiffness method and simulating the scattering wave fields with the dynamic Green's functions of moving distributed loads.The proposed method yields accurate results,because the 3-D dynamic stiffness matrixes used are exact and the fictitious moving distributed loads can be acted directly on the interface between the alluvial valley and the layered half-space without singularity.The comparison with the published methods verifies the validity of the proposed method.And the numerical analyses are performed to give some beneficial conclusions.The study shows that 3-D scattering by an alluvial valley is essentially different from the 2-D case,and that the presence of soil layer affects not only the amplitude value of surface displacements but also the distribution of surface displacements.展开更多
A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen （N） metabolism of a low-N tolerant mutant （lntl） of Arabidopsis thaliana under different N levels as compared ...A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen （N） metabolism of a low-N tolerant mutant （lntl） of Arabidopsis thaliana under different N levels as compared with the wild- type （WT） Arabidopsis. On the agar medium, no apparent growth differences were observed between the lntl and WT plants under a normal N level of 9 mmol L^-1 NO3. However, under a low N level of 0.18 mmol L^-1 NO3^-, the growth of the WT plants was greatly retarded, while the lntl plants were not affected by low-N stress and showed similar growth with those grown under a normal N level. In the hydroponics experiment, the lntl mutant had higher activities of glutamine synthetase （GS） and NADH-dependent glutamate synthase （NADH-GOGAT） in both leaves and roots under N-deficient conditions. Moreover, they accumulated less ammonium （NH4^＋） but more free amino acids in leaves compared with the WT plants. These observations suggest that better N assimilation might contribute to the low-N tolerant phenotype of the lnt1 mutant.展开更多
Fifty cases of regional yearly extreme precipitation events （RYEPEs） were identified over the Yangtze-Huaihe River Valley （YHRV） during 1979-2016 applying the statistical percentile method. There were five types o...Fifty cases of regional yearly extreme precipitation events （RYEPEs） were identified over the Yangtze-Huaihe River Valley （YHRV） during 1979-2016 applying the statistical percentile method. There were five types of RYEPEs, namely Yangtze Meiyu （YM-RYEPE）, Huaihe Meiyu （HM-RYEPE）, southwest-northeast-oriented Meiyu （SWNE-RYEPE） and typhoon I and II （TC-RYEPE） types of RYEPEs. Potential vorticity diagnosis showed that propagation trajectories of the RYEPEs along the Western Pacific Subtropical High and its steering flow were concentrated over the southern YHRV. As a result, the strongest and most frequently RYEPEs events, about 16-21 cases with average rainfall above 100 mm, occurred in the southern YHRV, particularly in the Nanjing metropolitan area. There have been 14 cases of flood-inducing RYEPEs since 1979, with the submerged area exceeding 120 km2 as simulated by the FloodArea hydraulic model, comprising six HM-RYEPEs, five YM- RYEPEs, two TC-RYEPEs, and one SWNE-RYEPE. The combination of evolving RYEPEs and rapid expansion of urban agglomeration is most likely to change the flood risk distribution over the Nanjing metropolitan area in the future. In the RCP6.0 （RCPS.5） scenario, the built-up area increases at a rate of about 10.41 km2 （10 yr）-t（24.67 km2 （10 yr）-1） from 2010 to 2100, and the area of high flood risk correspondingly increases from 3.86 km2（3.86 km2） to 9.00 kin2（13.51 km2）. Areas of high flood risk are mainly located at Chishan Lake in Jurong, Lukou International Airport in Nanjing, Dongshan in Jiangning District, Lishui District and other low-lying areas. The accurate simulation of flood scenarios can help reduce losses due to torrential flooding and improve early warnings, evacuation planning and risk analysis. More attention should be paid to the projected high flood risk because of the concentrated population, industrial zones and social wealth throughout the Nanjing metropolitan area.展开更多
文摘In the study, waterfront street in Honggutan was researched by field investigation and questionnaire survey from space, transport, scale and human activity. The waterfront street has the following characters： ambiguous spatial structure, a lack of spatial design; a lack of business diversity, and over-scaled street space. The scale of waterfront space is amenity, diversified and hydrophilic property. We analyzed and performed a parallel comparison on waterfront street space to help improve Honggutan waterfront street by analyzing its design principles, and taking references from outstanding cases at home and abroad.
基金Supported by National Natural Science Foundation of China (No. 50978156 and 50908183)Tianjin Research Programof Application Foundation and Advanced Technology(12JCQNJC04700)
文摘The indirect boundary element method(IBEM) was established to solve the problem of 3-D seismic responses of 2-D topographies,by calculating the free-field responses with the direct-stiffness method and simulating the scattering wave fields with the dynamic Green's functions of moving distributed loads.The proposed method yields accurate results,because the 3-D dynamic stiffness matrixes used are exact and the fictitious moving distributed loads can be acted directly on the interface between the alluvial valley and the layered half-space without singularity.The comparison with the published methods verifies the validity of the proposed method.And the numerical analyses are performed to give some beneficial conclusions.The study shows that 3-D scattering by an alluvial valley is essentially different from the 2-D case,and that the presence of soil layer affects not only the amplitude value of surface displacements but also the distribution of surface displacements.
基金Supported by the National Basic Research Program of China(No.2007CB109305)the National Natural Science Foundation of China(No.30370839)
文摘A growth experiment on agar medium and a hydroponics experiment were carried out to study the nitrogen （N） metabolism of a low-N tolerant mutant （lntl） of Arabidopsis thaliana under different N levels as compared with the wild- type （WT） Arabidopsis. On the agar medium, no apparent growth differences were observed between the lntl and WT plants under a normal N level of 9 mmol L^-1 NO3. However, under a low N level of 0.18 mmol L^-1 NO3^-, the growth of the WT plants was greatly retarded, while the lntl plants were not affected by low-N stress and showed similar growth with those grown under a normal N level. In the hydroponics experiment, the lntl mutant had higher activities of glutamine synthetase （GS） and NADH-dependent glutamate synthase （NADH-GOGAT） in both leaves and roots under N-deficient conditions. Moreover, they accumulated less ammonium （NH4^＋） but more free amino acids in leaves compared with the WT plants. These observations suggest that better N assimilation might contribute to the low-N tolerant phenotype of the lnt1 mutant.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41205063 & 41330529)the China Meteorological Administration Special Public Welfare Research Fund (Grant No. GYHY201506006)+1 种基金the Project of Development of Key Techniques in Meteorological Forecasting Operation (Grant No. CMAHX20160404)the Huaihe Basin Meteorological Research Foundation (Grant No. HRM201605)
文摘Fifty cases of regional yearly extreme precipitation events （RYEPEs） were identified over the Yangtze-Huaihe River Valley （YHRV） during 1979-2016 applying the statistical percentile method. There were five types of RYEPEs, namely Yangtze Meiyu （YM-RYEPE）, Huaihe Meiyu （HM-RYEPE）, southwest-northeast-oriented Meiyu （SWNE-RYEPE） and typhoon I and II （TC-RYEPE） types of RYEPEs. Potential vorticity diagnosis showed that propagation trajectories of the RYEPEs along the Western Pacific Subtropical High and its steering flow were concentrated over the southern YHRV. As a result, the strongest and most frequently RYEPEs events, about 16-21 cases with average rainfall above 100 mm, occurred in the southern YHRV, particularly in the Nanjing metropolitan area. There have been 14 cases of flood-inducing RYEPEs since 1979, with the submerged area exceeding 120 km2 as simulated by the FloodArea hydraulic model, comprising six HM-RYEPEs, five YM- RYEPEs, two TC-RYEPEs, and one SWNE-RYEPE. The combination of evolving RYEPEs and rapid expansion of urban agglomeration is most likely to change the flood risk distribution over the Nanjing metropolitan area in the future. In the RCP6.0 （RCPS.5） scenario, the built-up area increases at a rate of about 10.41 km2 （10 yr）-t（24.67 km2 （10 yr）-1） from 2010 to 2100, and the area of high flood risk correspondingly increases from 3.86 km2（3.86 km2） to 9.00 kin2（13.51 km2）. Areas of high flood risk are mainly located at Chishan Lake in Jurong, Lukou International Airport in Nanjing, Dongshan in Jiangning District, Lishui District and other low-lying areas. The accurate simulation of flood scenarios can help reduce losses due to torrential flooding and improve early warnings, evacuation planning and risk analysis. More attention should be paid to the projected high flood risk because of the concentrated population, industrial zones and social wealth throughout the Nanjing metropolitan area.
