Scirpus mariqueter Tang et Zhang is a typical pioneer plant colonizing the bare beaches of the Yangtse River estuary. To explore the life history strategy of the species with reference to environmental physical stre...Scirpus mariqueter Tang et Zhang is a typical pioneer plant colonizing the bare beaches of the Yangtse River estuary. To explore the life history strategy of the species with reference to environmental physical stress, the biomass allocations to different plant components and some related morphological parameters were examined along an elevational gradient within a salt marsh. Authors found that S. mariqueter performed best at medium elevation within the marsh, with relatively high density of shoot and individual ramet dry mass. Biomass allocation to corm was the highest at low elevations, and the least at high elevations, suggesting that a conservative strategy was adopted by the species to cope with the harsh physical conditions at the low elevation. The investment in rhizome decreased from low to high elevations, while the proportion of inflorescence mass increased, indicating that during the life history, the species shifts from predominant asexual reproduction to predominant sexual reproduction. This may be favourable for the species to colonize larger area, and to spread and persist at a meta_population level. Correlation analyses showed that sexual reproduction was inversely related to growth and asexual reproduction. However, it is difficult to determine the relationship between asexual reproduction and growth possibly because of the varied function of the corms of the species in different life history stages.展开更多
SOUTH Africa took over the continental seat at the helm of the trade and investment partnership between China and Africa, with a call to change the way business has been done over the past decade. In the partnership,...SOUTH Africa took over the continental seat at the helm of the trade and investment partnership between China and Africa, with a call to change the way business has been done over the past decade. In the partnership, Africa＇s main role has been to supply the giant Chinese economy with raw materials, a market for its products and a place for Chinese entrepreneurs to make money. China, on the other hand, has opened its credit lines to African countries, doling out concessional loans. It has also pumped in volumes of funds in investment, trained thousands of people and written-off billions of dollars worth of debt.展开更多
This paper concerns the need for improving the static and dynamic performance of the high voltage insulated gate bipolar transistor （HV IGBTs）. A novel structure with a carrier stored layer on the cathode side, know...This paper concerns the need for improving the static and dynamic performance of the high voltage insulated gate bipolar transistor （HV IGBTs）. A novel structure with a carrier stored layer on the cathode side, known as an enhanced planar IGBT of the 4500 V voltage class is investigated. With the adoption of a soft punch through （SPT） concept as the vertical structure and an enhanced planar concept as the top structure, signed as SPT＋ IGBT, the simulation results indicate the turn-off switching waveform of the 4500 V SPT＋ IGBT is soft and also realizes an improved trade-off relationship between on-state voltage drop （Von） and turn-off loss （Eoff） in comparison with the SPT IGBT. Attention is also paid to the influences caused by different carrier stored layer doping dose on static and dynamic performances, to optimize on-state and switching losses of SPT＋ IGBT.展开更多
China’s trade surplus amounted to $177.5 billion last year, an increase of $75.5 billion or a massive 74 percent over 2005. Trade officials said it is still within a normal range and its upward trend is due to the co...China’s trade surplus amounted to $177.5 billion last year, an increase of $75.5 billion or a massive 74 percent over 2005. Trade officials said it is still within a normal range and its upward trend is due to the country’s industrial and macroeconomic展开更多
China’s growing trade surplus has become a major concern for some of its major trade partners, such as the United States and the European Union. As the latest statistics from China’s Customs Administration suggest, ...China’s growing trade surplus has become a major concern for some of its major trade partners, such as the United States and the European Union. As the latest statistics from China’s Customs Administration suggest, while the country’s export growth rate fell 1.2 percentage points and that of imports rose 2.展开更多
文摘Scirpus mariqueter Tang et Zhang is a typical pioneer plant colonizing the bare beaches of the Yangtse River estuary. To explore the life history strategy of the species with reference to environmental physical stress, the biomass allocations to different plant components and some related morphological parameters were examined along an elevational gradient within a salt marsh. Authors found that S. mariqueter performed best at medium elevation within the marsh, with relatively high density of shoot and individual ramet dry mass. Biomass allocation to corm was the highest at low elevations, and the least at high elevations, suggesting that a conservative strategy was adopted by the species to cope with the harsh physical conditions at the low elevation. The investment in rhizome decreased from low to high elevations, while the proportion of inflorescence mass increased, indicating that during the life history, the species shifts from predominant asexual reproduction to predominant sexual reproduction. This may be favourable for the species to colonize larger area, and to spread and persist at a meta_population level. Correlation analyses showed that sexual reproduction was inversely related to growth and asexual reproduction. However, it is difficult to determine the relationship between asexual reproduction and growth possibly because of the varied function of the corms of the species in different life history stages.
文摘SOUTH Africa took over the continental seat at the helm of the trade and investment partnership between China and Africa, with a call to change the way business has been done over the past decade. In the partnership, Africa＇s main role has been to supply the giant Chinese economy with raw materials, a market for its products and a place for Chinese entrepreneurs to make money. China, on the other hand, has opened its credit lines to African countries, doling out concessional loans. It has also pumped in volumes of funds in investment, trained thousands of people and written-off billions of dollars worth of debt.
基金Project supported by the National Major Science and Technology Special Project of China(No.2011ZX02504-002)
文摘This paper concerns the need for improving the static and dynamic performance of the high voltage insulated gate bipolar transistor （HV IGBTs）. A novel structure with a carrier stored layer on the cathode side, known as an enhanced planar IGBT of the 4500 V voltage class is investigated. With the adoption of a soft punch through （SPT） concept as the vertical structure and an enhanced planar concept as the top structure, signed as SPT＋ IGBT, the simulation results indicate the turn-off switching waveform of the 4500 V SPT＋ IGBT is soft and also realizes an improved trade-off relationship between on-state voltage drop （Von） and turn-off loss （Eoff） in comparison with the SPT IGBT. Attention is also paid to the influences caused by different carrier stored layer doping dose on static and dynamic performances, to optimize on-state and switching losses of SPT＋ IGBT.
文摘China’s trade surplus amounted to $177.5 billion last year, an increase of $75.5 billion or a massive 74 percent over 2005. Trade officials said it is still within a normal range and its upward trend is due to the country’s industrial and macroeconomic
文摘China’s growing trade surplus has become a major concern for some of its major trade partners, such as the United States and the European Union. As the latest statistics from China’s Customs Administration suggest, while the country’s export growth rate fell 1.2 percentage points and that of imports rose 2.
