By utilization of different excitation power sources, linear plasma sources can be differentiated into DC, RF, VHF, microwave and dual frequency types. Through installing several linear plasma sources in parallel or a...By utilization of different excitation power sources, linear plasma sources can be differentiated into DC, RF, VHF, microwave and dual frequency types. Through installing several linear plasma sources in parallel or adopting the so-called roll-to-roll （air-to-air） process, scale uniform linear plasma sources were realized and successfully applied to the deposition of large area uniform dielectric thin films, Furthermore, the magnetic field system can effectively reduce the recombination losses on the wall of the vacuum chamber and enhance the plasma density. Linear plasma sources with approximately one square meter deposition area with the plasma density of 1011 cm 3 have been developed, some of which have been used for the deposition of dielectric layers and large area plasma etching.展开更多
Improving radiation use efficiency （RUE） of the canopy is necessary to increase wheat （Triticum aesfivum） production. Tridimensional uniform sowing （U） technology has previously been used to construct a uniforml...Improving radiation use efficiency （RUE） of the canopy is necessary to increase wheat （Triticum aesfivum） production. Tridimensional uniform sowing （U） technology has previously been used to construct a uniformly distributed population structure that increases RUE. In this study, we used tridimensional uniform sowing to create a wheat canopy within which light was spread evenly to increase RUE. This study was done during 2014-2016 in the Shunyi District, Beijing, China. The soil type was sandy loam. Wheat was grown in two sowing patterns： （1） tridimensional uniform sowing （U）; （2） conventional drilling （D）. Four planting densities were used： 1.8, 2.7, 3.6, and 4.5 million plants ha-1. Several indices were measured to compare the wheat canopies： photosynthetic active radiation intercepted by the canopy （IPAR）, leaf area index （LAI）, leaf mass per unit area （LMA）, canopy extinction coefficient （K）, and RUE. In two sowing patterns, the K values decreased with increasing planting density, but the K values of U were lower than that of D. LMA and IPAR were higher for U than for D, whereas LAI was nearly the same for both sowing patterns. IPAR and LAI increased with increasing density under the same sowing pattern. However, the difference in IPAR and LAI between the 3.6 and 4.5 million plants ha-1 treatments was not significant for both sowing patterns. Therefore, LAI within the same planting density was not affected by sowing pattern. RUE was the largest for the U mode with a planting density of 3.6 million plants ha-1 treatment. For the D sowing pattern, the lowest planting density （1.8 million plants ha-1） resulted in the highest yield. Light radiation interception was minimal for the D mode with a planting density of 1.8 million plants ha-1 treatment, but the highest RUE and highest yield were observed under this condition. For the U sowing pattern, IPAR increased with increasing planting density, but yield and RUE were the highest with a planting density of 3.6 million plants ha-1. These results indicated that the optimal planting density for improving the canopy light environment differed between the sowing patterns. The effect of sowing patternxplanting density interaction on grain yield, yield components, RUE, IPAR, and LMA was significant （P〈0.05）. Correlation analysis indicated that there is a positive significant correlation between grain yield and RUE （t=0.880, P〈0.01）, LMA （r=0.613, P〈0.05）, andspike number （t=0.624, P〈0.05）. These results demonstrated that the tridimensional uniform sowing technique, particularly at a planting density of 3.6 million plants ha-0, can effectively increase light interception and utilization and unit leaf area. This leads to the production of more photosynthetic products that in turn lead to significantly increased spike number （P〈0.05）, kernel number, grain weight, and an overall increase in yield.展开更多
Based on two-dimensional （2D） rigid-plastic finite element （FE） method, the optimum observation area for metallographic microstructure and the influence of the height-diameter ratio on which were analyzed for the ...Based on two-dimensional （2D） rigid-plastic finite element （FE） method, the optimum observation area for metallographic microstructure and the influence of the height-diameter ratio on which were analyzed for the cylindrical samples with the diameter of 8 mm and different heights from 8 to 16 mm in nonuniform compressive experiments. It is shown that the representative metallographic observation area relevant to the applied deformation condition is located at about 0.835 of the radius from the center of the sample to the solder joint between the sample and the thermocouples. At the same time, the microstructure in that area is more appropriate as the height of the sample is 12 mm. The related parameters of GH4033 superalloy were adopted in the FE analysis, and the validity of this analysis was verified by the compressive experiments.展开更多
基金supported by National Natural Science Foundation of China(No.11205201)
文摘By utilization of different excitation power sources, linear plasma sources can be differentiated into DC, RF, VHF, microwave and dual frequency types. Through installing several linear plasma sources in parallel or adopting the so-called roll-to-roll （air-to-air） process, scale uniform linear plasma sources were realized and successfully applied to the deposition of large area uniform dielectric thin films, Furthermore, the magnetic field system can effectively reduce the recombination losses on the wall of the vacuum chamber and enhance the plasma density. Linear plasma sources with approximately one square meter deposition area with the plasma density of 1011 cm 3 have been developed, some of which have been used for the deposition of dielectric layers and large area plasma etching.
基金supported by the National Key Research and Development Program of China (2016YFD0300407)the earmarked fund for China Agriculture Research System (CARS-03)
文摘Improving radiation use efficiency （RUE） of the canopy is necessary to increase wheat （Triticum aesfivum） production. Tridimensional uniform sowing （U） technology has previously been used to construct a uniformly distributed population structure that increases RUE. In this study, we used tridimensional uniform sowing to create a wheat canopy within which light was spread evenly to increase RUE. This study was done during 2014-2016 in the Shunyi District, Beijing, China. The soil type was sandy loam. Wheat was grown in two sowing patterns： （1） tridimensional uniform sowing （U）; （2） conventional drilling （D）. Four planting densities were used： 1.8, 2.7, 3.6, and 4.5 million plants ha-1. Several indices were measured to compare the wheat canopies： photosynthetic active radiation intercepted by the canopy （IPAR）, leaf area index （LAI）, leaf mass per unit area （LMA）, canopy extinction coefficient （K）, and RUE. In two sowing patterns, the K values decreased with increasing planting density, but the K values of U were lower than that of D. LMA and IPAR were higher for U than for D, whereas LAI was nearly the same for both sowing patterns. IPAR and LAI increased with increasing density under the same sowing pattern. However, the difference in IPAR and LAI between the 3.6 and 4.5 million plants ha-1 treatments was not significant for both sowing patterns. Therefore, LAI within the same planting density was not affected by sowing pattern. RUE was the largest for the U mode with a planting density of 3.6 million plants ha-1 treatment. For the D sowing pattern, the lowest planting density （1.8 million plants ha-1） resulted in the highest yield. Light radiation interception was minimal for the D mode with a planting density of 1.8 million plants ha-1 treatment, but the highest RUE and highest yield were observed under this condition. For the U sowing pattern, IPAR increased with increasing planting density, but yield and RUE were the highest with a planting density of 3.6 million plants ha-1. These results indicated that the optimal planting density for improving the canopy light environment differed between the sowing patterns. The effect of sowing patternxplanting density interaction on grain yield, yield components, RUE, IPAR, and LMA was significant （P〈0.05）. Correlation analysis indicated that there is a positive significant correlation between grain yield and RUE （t=0.880, P〈0.01）, LMA （r=0.613, P〈0.05）, andspike number （t=0.624, P〈0.05）. These results demonstrated that the tridimensional uniform sowing technique, particularly at a planting density of 3.6 million plants ha-0, can effectively increase light interception and utilization and unit leaf area. This leads to the production of more photosynthetic products that in turn lead to significantly increased spike number （P〈0.05）, kernel number, grain weight, and an overall increase in yield.
基金supported by the National Natural Science Foundation of China (No. 51274062)
文摘Based on two-dimensional （2D） rigid-plastic finite element （FE） method, the optimum observation area for metallographic microstructure and the influence of the height-diameter ratio on which were analyzed for the cylindrical samples with the diameter of 8 mm and different heights from 8 to 16 mm in nonuniform compressive experiments. It is shown that the representative metallographic observation area relevant to the applied deformation condition is located at about 0.835 of the radius from the center of the sample to the solder joint between the sample and the thermocouples. At the same time, the microstructure in that area is more appropriate as the height of the sample is 12 mm. The related parameters of GH4033 superalloy were adopted in the FE analysis, and the validity of this analysis was verified by the compressive experiments.
