【目的】拟探讨等距单粒线播技术用于定量种间距对小麦前、后生育期的影响,以此论证等距单粒线播的技术特征及优势。【方法】选用宁麦13为田间试验材料,采用免耕等距单粒线播法,分别于2017和2018年进行稻茬小麦的免耕种植试验,设置粒距...【目的】拟探讨等距单粒线播技术用于定量种间距对小麦前、后生育期的影响,以此论证等距单粒线播的技术特征及优势。【方法】选用宁麦13为田间试验材料,采用免耕等距单粒线播法,分别于2017和2018年进行稻茬小麦的免耕种植试验,设置粒距1.5、3.0和4.5 cm 3个处理(T1.5、T3、T4.5),行距20 cm。分别从群体、单株以及单茎穗3个尺度层次的指标对比,评价种间距在苗期和成熟期的生理生态效应。【结果】等距单粒线播法创建出稳定全生育期密度效应且该效应能够为群体、单株与器官3个尺度层次的表型所表达。较小种间距显著延长稻茬麦50%出苗率的天数。群体的成熟期籽粒总产量随种间距减小而增加,T1.5与T3处理无显著性差异,但T4.5处理显著降低。在群体生物量方面,T4.5处理的总茎秆重、总麦穗重显著低于T1.5和T3处理。而在单株尺度层面,单株穗数、结实粒数和单株产量随种间距增加而显著性增大,但单株千粒重无显著性差异,单株小麦的地上部生物量、麦穗重和茎秆重也随播种间距增加而增大,表现出明显的密度补偿效应。同时,随种间距减小,单株小麦各指标由正态分布变为L型分布。在小麦的单茎穗层面,单茎穗产量和穗千粒重均无显著性差异,仅穗粒数表现出年度间不稳定。而在器官生物量方面,地上部生物量、叶重、茎秆重和麦穗重不同处理下均无显著性差异。【结论】等距单粒线播小麦在群体、个体和器官3个不同尺度范畴的密度效应能够在小麦的苗期和成熟期得到充分表达,且不同尺度范畴内的产量因子及生物量等表型指标存在复杂的交互关系。因此,相较于传统机械化种植技术,等距单粒线播技术有利于解析群体小麦的生理生态效应。展开更多
The comparative advantage of maize production in Jilin Province was analyzed based on the sow area index,unit yield index,benefit index and comprehensive comparative advantage index in this study.The results showed th...The comparative advantage of maize production in Jilin Province was analyzed based on the sow area index,unit yield index,benefit index and comprehensive comparative advantage index in this study.The results showed that compared with other provinces in China,there was obvious comparative advantage in sow area index and unit yield index of maize in Jilin,the average of which stood for the first and the fourth in China from 2002 to 2006;there was no comparative advantage of benefit index compared with the average value of the whole countries,the average of which stood for the 14th in China from 2002 to 2006;the comprehensive comparative advantage in Jilin provincial maize production showed significant comparative advantage,the average of which stood for the fourth in China from 2002 to 2006.On the basis of the above,the suggestions to develop maize production in Jilin province had been put forward.展开更多
An improved internetworking approach is proposed to enhance the Internet connectivity which is deteriorated due to unidirectional links and blind rebroadcasting of gateway discovery packets for mobile ad hoc networks....An improved internetworking approach is proposed to enhance the Internet connectivity which is deteriorated due to unidirectional links and blind rebroadcasting of gateway discovery packets for mobile ad hoc networks. The hybrid gateway discovery scheme that combined the advantages of a proactive and reactive gateway discovery approach is used to achieve high connectivity while keeping overhead costs low. By exchanging ad hoc on-demand distance vector （AODV） hello packet which includes additional fields named symmetric neighbor list and asymmetric neighbor list, unidirectional links are removed from route computation and broadcast storm can also be relieved simultaneously. Performance results using ns-2 simulations, under varying numbers of unidirectional links and node speeds, show that this improved Internet connectivity approach can provide better performance than others.展开更多
The implementation of a programmable frequency divider, which is one of the components of the phase-locked loop （PLL） frequency synthesizer for digital video broadcastingterrestrial （DVB-T） and other modem communi...The implementation of a programmable frequency divider, which is one of the components of the phase-locked loop （PLL） frequency synthesizer for digital video broadcastingterrestrial （DVB-T） and other modem communication systems, is presented. By cooperating with a dual-modulus prescaler, this divider can realize an integer frequency division from 926 to 1 387. Besides the traditional standard cell design flow, such as logic synthesis, placement and routing, the interactions between front-end and back-end are also considered to optimize the design flow under deep submicron technology. By back-annotating the back-end information to front-end design, a custom wire-load model is created which is more practical compared with the default model. This divider has been fabricated in TSMC 0. 18μm CMOS technology using Artisan standard cell library. The chip area is 675 μm × 475 μm and the power consumption is about 2 mW under a 1.8 V power supply. Measurement results show that it works correctly and can realize a frequency division with high precision.展开更多
[Objective]The aim was to establish the linear regression prediction models between sowing time and plant productivity, biological yield of forage sorghum in autumn idle land.[Method]The relationships between sowing t...[Objective]The aim was to establish the linear regression prediction models between sowing time and plant productivity, biological yield of forage sorghum in autumn idle land.[Method]The relationships between sowing time and plant productivity, biological yield of forage sorghum were simulated and compared by using field experiment and linear regression analysis.[Result] The sowing time had an important influence on the plant productivity and biological yield of forage sorghum in autumn idle land. The plant productivity and biological yield of forage sorghum both decreased with the delay of sowing time.The regression model between plant fresh weight and sowing time was ？fresh=0.618-0.015x; the regression model between plant dry weight and sowing time was ？dry=0.184-0.005x; and the regression model between biological yield and sowing time was yield=29 126.461-711.448x. During July 23rd to August 30th, when the sowing time was delayed by 1 day, the plant fresh weight of forage sorghum was reduced by 0.015 g, the plant dry weight was reduced by 0.005 g, and the yield was reduced by 711.448 kg/hm2. [Conclusion] The three regression models established in this study will provide theoretical support for the production of forage sorghum.展开更多
By introducing XOR operation and one-way function chains to group key management schemes based on the keys tree, a new group key management scheme based on the keys tree, XOR operation and one-way function chains is p...By introducing XOR operation and one-way function chains to group key management schemes based on the keys tree, a new group key management scheme based on the keys tree, XOR operation and one-way function chains is proposed. Initialization, member adding and member evicting operations are introduced. The new scheme is compared with three other group key management schemes which are based on the keys tree： SKDC, LKH, and OFF. As far as transmission, computation and storage costs are concerned, the performance of the new group key management scheme is the best. The security problem of the new scheme is analyzed. This new scheme provides backward and forward security, i.e.. newly admitted group members cannot read previous multicast messages and evicted members cannot read future multicast messages, even with collusion by many arbitrarily evicted members.展开更多
文摘【目的】拟探讨等距单粒线播技术用于定量种间距对小麦前、后生育期的影响,以此论证等距单粒线播的技术特征及优势。【方法】选用宁麦13为田间试验材料,采用免耕等距单粒线播法,分别于2017和2018年进行稻茬小麦的免耕种植试验,设置粒距1.5、3.0和4.5 cm 3个处理(T1.5、T3、T4.5),行距20 cm。分别从群体、单株以及单茎穗3个尺度层次的指标对比,评价种间距在苗期和成熟期的生理生态效应。【结果】等距单粒线播法创建出稳定全生育期密度效应且该效应能够为群体、单株与器官3个尺度层次的表型所表达。较小种间距显著延长稻茬麦50%出苗率的天数。群体的成熟期籽粒总产量随种间距减小而增加,T1.5与T3处理无显著性差异,但T4.5处理显著降低。在群体生物量方面,T4.5处理的总茎秆重、总麦穗重显著低于T1.5和T3处理。而在单株尺度层面,单株穗数、结实粒数和单株产量随种间距增加而显著性增大,但单株千粒重无显著性差异,单株小麦的地上部生物量、麦穗重和茎秆重也随播种间距增加而增大,表现出明显的密度补偿效应。同时,随种间距减小,单株小麦各指标由正态分布变为L型分布。在小麦的单茎穗层面,单茎穗产量和穗千粒重均无显著性差异,仅穗粒数表现出年度间不稳定。而在器官生物量方面,地上部生物量、叶重、茎秆重和麦穗重不同处理下均无显著性差异。【结论】等距单粒线播小麦在群体、个体和器官3个不同尺度范畴的密度效应能够在小麦的苗期和成熟期得到充分表达,且不同尺度范畴内的产量因子及生物量等表型指标存在复杂的交互关系。因此,相较于传统机械化种植技术,等距单粒线播技术有利于解析群体小麦的生理生态效应。
基金Supported by Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-year Plan Period(2007BAD98B06)Scientific Research Foundation of Jilin Agricultural University~~
文摘The comparative advantage of maize production in Jilin Province was analyzed based on the sow area index,unit yield index,benefit index and comprehensive comparative advantage index in this study.The results showed that compared with other provinces in China,there was obvious comparative advantage in sow area index and unit yield index of maize in Jilin,the average of which stood for the first and the fourth in China from 2002 to 2006;there was no comparative advantage of benefit index compared with the average value of the whole countries,the average of which stood for the 14th in China from 2002 to 2006;the comprehensive comparative advantage in Jilin provincial maize production showed significant comparative advantage,the average of which stood for the fourth in China from 2002 to 2006.On the basis of the above,the suggestions to develop maize production in Jilin province had been put forward.
基金The National Natural Science Foundation of China(No60362001)
文摘An improved internetworking approach is proposed to enhance the Internet connectivity which is deteriorated due to unidirectional links and blind rebroadcasting of gateway discovery packets for mobile ad hoc networks. The hybrid gateway discovery scheme that combined the advantages of a proactive and reactive gateway discovery approach is used to achieve high connectivity while keeping overhead costs low. By exchanging ad hoc on-demand distance vector （AODV） hello packet which includes additional fields named symmetric neighbor list and asymmetric neighbor list, unidirectional links are removed from route computation and broadcast storm can also be relieved simultaneously. Performance results using ns-2 simulations, under varying numbers of unidirectional links and node speeds, show that this improved Internet connectivity approach can provide better performance than others.
基金The National Natural Science Foundation of China(No.60472057)
文摘The implementation of a programmable frequency divider, which is one of the components of the phase-locked loop （PLL） frequency synthesizer for digital video broadcastingterrestrial （DVB-T） and other modem communication systems, is presented. By cooperating with a dual-modulus prescaler, this divider can realize an integer frequency division from 926 to 1 387. Besides the traditional standard cell design flow, such as logic synthesis, placement and routing, the interactions between front-end and back-end are also considered to optimize the design flow under deep submicron technology. By back-annotating the back-end information to front-end design, a custom wire-load model is created which is more practical compared with the default model. This divider has been fabricated in TSMC 0. 18μm CMOS technology using Artisan standard cell library. The chip area is 675 μm × 475 μm and the power consumption is about 2 mW under a 1.8 V power supply. Measurement results show that it works correctly and can realize a frequency division with high precision.
文摘[Objective]The aim was to establish the linear regression prediction models between sowing time and plant productivity, biological yield of forage sorghum in autumn idle land.[Method]The relationships between sowing time and plant productivity, biological yield of forage sorghum were simulated and compared by using field experiment and linear regression analysis.[Result] The sowing time had an important influence on the plant productivity and biological yield of forage sorghum in autumn idle land. The plant productivity and biological yield of forage sorghum both decreased with the delay of sowing time.The regression model between plant fresh weight and sowing time was ？fresh=0.618-0.015x; the regression model between plant dry weight and sowing time was ？dry=0.184-0.005x; and the regression model between biological yield and sowing time was yield=29 126.461-711.448x. During July 23rd to August 30th, when the sowing time was delayed by 1 day, the plant fresh weight of forage sorghum was reduced by 0.015 g, the plant dry weight was reduced by 0.005 g, and the yield was reduced by 711.448 kg/hm2. [Conclusion] The three regression models established in this study will provide theoretical support for the production of forage sorghum.
文摘By introducing XOR operation and one-way function chains to group key management schemes based on the keys tree, a new group key management scheme based on the keys tree, XOR operation and one-way function chains is proposed. Initialization, member adding and member evicting operations are introduced. The new scheme is compared with three other group key management schemes which are based on the keys tree： SKDC, LKH, and OFF. As far as transmission, computation and storage costs are concerned, the performance of the new group key management scheme is the best. The security problem of the new scheme is analyzed. This new scheme provides backward and forward security, i.e.. newly admitted group members cannot read previous multicast messages and evicted members cannot read future multicast messages, even with collusion by many arbitrarily evicted members.
