The phenomenon of the soil plug usually rising inside the suction foundations during suction penetration was quantitatively described and predicted. The formation process of the soil plug was simulated and calculated ...The phenomenon of the soil plug usually rising inside the suction foundations during suction penetration was quantitatively described and predicted. The formation process of the soil plug was simulated and calculated by DEM （discrete element method） model. The seepage flow, the self-weight of soil, the friction on the chamber wall as well as the suction inside the chamber are considered as the main external forces in the process. The results are compared with a set of laboratory model tests performed by using three soil types （sand, silty clay and clay） in the Bohai Sea area. The heights of soil plug from numerical estimations are lower than those from model test results, mainly because the suction pressure and friction resistance are applied in an ideal way under the numerical simulation.展开更多
Several Chinese Iris species have potential for medicinal and ornamental use, but they have poor, erratic or slow seed germination. The aims of this study was to classify Iris ehrysographes dormancy type and investiga...Several Chinese Iris species have potential for medicinal and ornamental use, but they have poor, erratic or slow seed germination. The aims of this study was to classify Iris ehrysographes dormancy type and investigate the optimum treatment for seeds germination through examining the effects of various incubation temperatures, light conditions, scarification, stratification and soil substratum. Seed viability of/. chrysographes was 74% and seeds imbibed water very fast. No seeds germinated on stratification, soil substratum, constant or alternating temperatures, light and darkness treatments. Seeds germination of different mechanical restriction treatments had significant differences. The results indicated that： （1） removal of seed coat was the most effective treatment for/. chrysographes germination; （2） physiological dormancy phenomenon was found in this species.展开更多
Gandaki River Basin(GRB) is part of the central Himalayan region, which provides habitat for numerous wild species. However, due to changes in climate and land cover, the habitats of many protected species are at risk...Gandaki River Basin(GRB) is part of the central Himalayan region, which provides habitat for numerous wild species. However, due to changes in climate and land cover, the habitats of many protected species are at risk. Based on the maximum entropy(MaxEnt) model, coupled with bioclimatic layers, land cover and DEM data, the impacts of environmental factors on habitat suitability of Himalayan Monal(Lophophorus impejanus), a national bird of Nepal, was quantified. This study further assessed the present and future habitat and distribution of the Himalayan Monal in the context of climate and land cover changes. The results of this study show that the highly suitable habitat of Himalayan Monal presently occupies around 749 km^2 within the northern, eastern and western parts, particularly protected areas such as Langtang National Park, Manaslu Conservation Area and Annapurna Conservation Area, while it is likely to decrease to 561 km^2 by 2050, primarily in the northern and northwestern parts(i.e., Chhyo, Tatopani, Humde and Chame). These expected changes indicate increasing risk for Himalayan Monal due to a decline in its suitable habitat area.展开更多
An edge colored graph G is rainbow connected if any two vertices are connected by a path whose edges have distinct colors. The rainbow connection number of a graph G, denoted by rc(G), is the smallest number of colors...An edge colored graph G is rainbow connected if any two vertices are connected by a path whose edges have distinct colors. The rainbow connection number of a graph G, denoted by rc(G), is the smallest number of colors that are needed in order to make G rainbow connected. A vertex colored graph G is vertex rainbow connected if any two vertices are connected by a path whose internal vertices have distinct colors. The vertex rainbow connection number of G, denoted by rvc(G), is the smallest number of colors that are needed in order to make G vertex rainbow connected. In 2011, Kemnitz and Schiermeyer considered graphs with rc(G) = 2.We investigate graphs with rvc(G) = 2. First, we prove that rvc(G) 2 if |E(G)|≥n-22 + 2, and the bound is sharp. Denote by s(n, 2) the minimum number such that, for each graph G of order n, we have rvc(G) 2provided |E(G)|≥s(n, 2). It is proved that s(n, 2) = n-22 + 2. Next, we characterize the vertex rainbow connection numbers of graphs G with |V(G)| = n, diam(G)≥3 and clique number ω(G) = n- s for 1≤s≤4.展开更多
基金SUPPORTED BY NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA ( NO. 50079016).
文摘The phenomenon of the soil plug usually rising inside the suction foundations during suction penetration was quantitatively described and predicted. The formation process of the soil plug was simulated and calculated by DEM （discrete element method） model. The seepage flow, the self-weight of soil, the friction on the chamber wall as well as the suction inside the chamber are considered as the main external forces in the process. The results are compared with a set of laboratory model tests performed by using three soil types （sand, silty clay and clay） in the Bohai Sea area. The heights of soil plug from numerical estimations are lower than those from model test results, mainly because the suction pressure and friction resistance are applied in an ideal way under the numerical simulation.
文摘Several Chinese Iris species have potential for medicinal and ornamental use, but they have poor, erratic or slow seed germination. The aims of this study was to classify Iris ehrysographes dormancy type and investigate the optimum treatment for seeds germination through examining the effects of various incubation temperatures, light conditions, scarification, stratification and soil substratum. Seed viability of/. chrysographes was 74% and seeds imbibed water very fast. No seeds germinated on stratification, soil substratum, constant or alternating temperatures, light and darkness treatments. Seeds germination of different mechanical restriction treatments had significant differences. The results indicated that： （1） removal of seed coat was the most effective treatment for/. chrysographes germination; （2） physiological dormancy phenomenon was found in this species.
基金Chinese Academy of Sciences-The World Academy of Sciences(CAS-TWAS)President's Fellowship Program for PhD Study。
文摘Gandaki River Basin(GRB) is part of the central Himalayan region, which provides habitat for numerous wild species. However, due to changes in climate and land cover, the habitats of many protected species are at risk. Based on the maximum entropy(MaxEnt) model, coupled with bioclimatic layers, land cover and DEM data, the impacts of environmental factors on habitat suitability of Himalayan Monal(Lophophorus impejanus), a national bird of Nepal, was quantified. This study further assessed the present and future habitat and distribution of the Himalayan Monal in the context of climate and land cover changes. The results of this study show that the highly suitable habitat of Himalayan Monal presently occupies around 749 km^2 within the northern, eastern and western parts, particularly protected areas such as Langtang National Park, Manaslu Conservation Area and Annapurna Conservation Area, while it is likely to decrease to 561 km^2 by 2050, primarily in the northern and northwestern parts(i.e., Chhyo, Tatopani, Humde and Chame). These expected changes indicate increasing risk for Himalayan Monal due to a decline in its suitable habitat area.
基金supported by National Natural Science Foundation of China(Grant Nos.11271267 and 11371204)
文摘An edge colored graph G is rainbow connected if any two vertices are connected by a path whose edges have distinct colors. The rainbow connection number of a graph G, denoted by rc(G), is the smallest number of colors that are needed in order to make G rainbow connected. A vertex colored graph G is vertex rainbow connected if any two vertices are connected by a path whose internal vertices have distinct colors. The vertex rainbow connection number of G, denoted by rvc(G), is the smallest number of colors that are needed in order to make G vertex rainbow connected. In 2011, Kemnitz and Schiermeyer considered graphs with rc(G) = 2.We investigate graphs with rvc(G) = 2. First, we prove that rvc(G) 2 if |E(G)|≥n-22 + 2, and the bound is sharp. Denote by s(n, 2) the minimum number such that, for each graph G of order n, we have rvc(G) 2provided |E(G)|≥s(n, 2). It is proved that s(n, 2) = n-22 + 2. Next, we characterize the vertex rainbow connection numbers of graphs G with |V(G)| = n, diam(G)≥3 and clique number ω(G) = n- s for 1≤s≤4.
