The T-gate stem height of In Al As/In Ga As In P-based high electron mobility transistor(HEMT) is increased from165 nm to 250 nm. The influences of increasing the gate stem height on the direct current(DC) and radio f...The T-gate stem height of In Al As/In Ga As In P-based high electron mobility transistor(HEMT) is increased from165 nm to 250 nm. The influences of increasing the gate stem height on the direct current(DC) and radio frequency(RF)performances of device are investigated. A 120-nm-long gate, 250-nm-high gate stem device exhibits a higher threshold voltage(Vth) of 60 m V than a 120-nm-long gate devices with a short gate stem, caused by more Pt distributions on the gate foot edges of the high Ti/Pt/Au gate. The Pt distribution in Schottky contact metal is found to increase with the gate stem height or the gate length increasing, and thus enhancing the Schottky barrier height and expanding the gate length,which can be due to the increased internal tensile stress of Pt. The more Pt distributions for the high gate stem device also lead to more obvious Pt sinking, which reduces the distance between the gate and the In Ga As channel so that the transconductance(gm) of the high gate stem device is 70 m S/mm larger than that of the short stem device. As for the RF performances,the gate extrinsic parasitic capacitance decreases and the intrinsic transconductance increases after the gate stem height has been increased, so the RF performances of device are obviously improved. The high gate stem device yields a maximum ft of 270 GHz and fmax of 460 GHz, while the short gate stem device has a maximum ft of 240 GHz and the fmax of 370 GHz.展开更多
In order to mine gene loci associated with drought resistance and water use efficiency, and provide guidance for the breeding of drought-resistant wheat varieties, quantitative trait loci （QTLs） for plant height （P...In order to mine gene loci associated with drought resistance and water use efficiency, and provide guidance for the breeding of drought-resistant wheat varieties, quantitative trait loci （QTLs） for plant height （PH） and stem height （SH） of wheat were evaluated using a population of 302 recombinant inbred lines （RILs） derived from a cress between drought-tolerant cultivar Luohan 2 and water-sensitive cultivar Weimai 8 under different water regimes in six environments. Totally 17 additive QTLs for PH and SH were identified and distributed on chromosomes 2B, 3A, 3B, 4A, 5A, 5D, 6B, 7A and 7B, respectively, which explained 3.3% to 26.95% phenotypic variations, with additive effect of 1.919 6 to 5.382 8 cm. Among them, 14 QTLs, 24 times and 5 QTLs, 7 times were detected in three irrigation environments and three drought stress environments, respectively. Both the number of QTLs for PH and the times detected in drought stress environments were significantly less than those in irrigation environments. Of all the 17 QTLs for PH, 12 were detected only in irrigation environment, three QTLs were detected only in drought stress environment, and two QTLs were detected in both environments, suggesting that the expression of the genes is greatly influenced by en- vironmental condition. QPh-WL-7A. 3 detected between maker Xbarc049 and Xgwm273 on chromosome 7A in all the three drought stress environments, can enhance 2.481 5 - 3. 697 2 cm of PH, explain 8.6% - 10.0% additive effect, so it is useful for the genetic improvement of drought tolerance and molecular marker-assisted selection in wheat.展开更多
In order to explore the differences in the compressive strength parallel to grain （CSPG） between different clones and individual woods of Populus deltoides Marsh., the CSPGs of 5 15-year-old P. deltoides clones were...In order to explore the differences in the compressive strength parallel to grain （CSPG） between different clones and individual woods of Populus deltoides Marsh., the CSPGs of 5 15-year-old P. deltoides clones were determined and analyzed. The results showed that there were significant differences in CSPG of wood between different clones of P. deltoides . The CSPG of the tested clones reached more than 41 MPa, which was higher than the average compressive strength of P. deltoides （32.94 MPa）. Similar to the changes of stem height, the CSPG of the clones gradually increased with the increase of stem height. However, there were significant differences in CSPG of an individual plant at different tree heights. The CSPG of P. deltoides clones was related with their growth traits, but not significantly. Therefore, it is expected to achieve simultaneous and independent improvement on CSPG and the growth of P. deltoides , so as to get excellent individuals with fast growth and high CSPG.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61434006)。
文摘The T-gate stem height of In Al As/In Ga As In P-based high electron mobility transistor(HEMT) is increased from165 nm to 250 nm. The influences of increasing the gate stem height on the direct current(DC) and radio frequency(RF)performances of device are investigated. A 120-nm-long gate, 250-nm-high gate stem device exhibits a higher threshold voltage(Vth) of 60 m V than a 120-nm-long gate devices with a short gate stem, caused by more Pt distributions on the gate foot edges of the high Ti/Pt/Au gate. The Pt distribution in Schottky contact metal is found to increase with the gate stem height or the gate length increasing, and thus enhancing the Schottky barrier height and expanding the gate length,which can be due to the increased internal tensile stress of Pt. The more Pt distributions for the high gate stem device also lead to more obvious Pt sinking, which reduces the distance between the gate and the In Ga As channel so that the transconductance(gm) of the high gate stem device is 70 m S/mm larger than that of the short stem device. As for the RF performances,the gate extrinsic parasitic capacitance decreases and the intrinsic transconductance increases after the gate stem height has been increased, so the RF performances of device are obviously improved. The high gate stem device yields a maximum ft of 270 GHz and fmax of 460 GHz, while the short gate stem device has a maximum ft of 240 GHz and the fmax of 370 GHz.
基金Supported by Scientific and Technological Development Plan of Jining Municipal Government(2013CB030102)Key Technological Project for Independent Innovation of Shandong Province(2014GJJS0201)
文摘In order to mine gene loci associated with drought resistance and water use efficiency, and provide guidance for the breeding of drought-resistant wheat varieties, quantitative trait loci （QTLs） for plant height （PH） and stem height （SH） of wheat were evaluated using a population of 302 recombinant inbred lines （RILs） derived from a cress between drought-tolerant cultivar Luohan 2 and water-sensitive cultivar Weimai 8 under different water regimes in six environments. Totally 17 additive QTLs for PH and SH were identified and distributed on chromosomes 2B, 3A, 3B, 4A, 5A, 5D, 6B, 7A and 7B, respectively, which explained 3.3% to 26.95% phenotypic variations, with additive effect of 1.919 6 to 5.382 8 cm. Among them, 14 QTLs, 24 times and 5 QTLs, 7 times were detected in three irrigation environments and three drought stress environments, respectively. Both the number of QTLs for PH and the times detected in drought stress environments were significantly less than those in irrigation environments. Of all the 17 QTLs for PH, 12 were detected only in irrigation environment, three QTLs were detected only in drought stress environment, and two QTLs were detected in both environments, suggesting that the expression of the genes is greatly influenced by en- vironmental condition. QPh-WL-7A. 3 detected between maker Xbarc049 and Xgwm273 on chromosome 7A in all the three drought stress environments, can enhance 2.481 5 - 3. 697 2 cm of PH, explain 8.6% - 10.0% additive effect, so it is useful for the genetic improvement of drought tolerance and molecular marker-assisted selection in wheat.
基金Supported by the Major Science and Technology Program of Hunan Province(2017NK1010)the Research on High Efficient Cultivation of Populus deltoids Industrial Resources in Dongting Lake Area,the Special Found for the Development and Efficient Utilization Technology Innovation of Forestry Resources during the"13th Five-Year Plan"(2016YFD0600402-2)the Research and Demonstration of Populus Engineering Structural Materials Directional Cultivation and Value-Added Key Technologies,the Science and Technology Planning Project for Forestry of Hunan Province(XLK201506)
文摘In order to explore the differences in the compressive strength parallel to grain （CSPG） between different clones and individual woods of Populus deltoides Marsh., the CSPGs of 5 15-year-old P. deltoides clones were determined and analyzed. The results showed that there were significant differences in CSPG of wood between different clones of P. deltoides . The CSPG of the tested clones reached more than 41 MPa, which was higher than the average compressive strength of P. deltoides （32.94 MPa）. Similar to the changes of stem height, the CSPG of the clones gradually increased with the increase of stem height. However, there were significant differences in CSPG of an individual plant at different tree heights. The CSPG of P. deltoides clones was related with their growth traits, but not significantly. Therefore, it is expected to achieve simultaneous and independent improvement on CSPG and the growth of P. deltoides , so as to get excellent individuals with fast growth and high CSPG.
