【目的】探索黄淮地区冬小麦适宜水氮管理模式。【方法】通过田间小区试验,研究了不同灌水量(90 mm (W1)、60 mm (W2)、0 mm (W3))和施氮量(300 kg/hm2(N1)、225 kg/hm2(N2)、150 kg/hm2(N3))对冬小麦耗水特性、产量和水分利用效率的影...【目的】探索黄淮地区冬小麦适宜水氮管理模式。【方法】通过田间小区试验,研究了不同灌水量(90 mm (W1)、60 mm (W2)、0 mm (W3))和施氮量(300 kg/hm2(N1)、225 kg/hm2(N2)、150 kg/hm2(N3))对冬小麦耗水特性、产量和水分利用效率的影响。【结果】灌水量从0增加到90 mm,冬小麦耗水量增加了67～106 mm,降水和土壤供水量占耗水量的比例降低;随施氮量增加,冬小麦耗水量和土壤供水占耗水量的比例增加,降水所占比例降低。相同灌水条件下,灌水量和降水量占总耗水量比例随施氮量增加而降低;施氮量从150 kg/hm2增加到300 kg/hm2,土壤贮水量消耗占总耗水量的比例从1.6%～4.9%增加到8.3%～9.9%。拔节期灌水、追施氮肥提高了拔节—开花期、开花—成熟期阶段耗水量和平均日耗水强度;与W3N3处理相比,随灌水和施氮量的增加,拔节—成熟期的耗水量增加了7.4%～63.5%;增加灌水量降低了冬小麦水分利用效率、土壤水利用效率和灌溉水利用效率,提高了降水利用效率。在W1条件下,N1、N2处理的水分利用效率、降水利用效率和灌溉水利用效率分别比N3提高了18.18%～22.98%、24.66%～26.32%和24.68%～26.32%;在W2、W3条件下,水分利用效率、降水利用效率、灌溉水利用效率随施氮量的增加逐渐增加,土壤水利用效率随着施氮量增加逐渐减小。【结论】在试验条件下,综合考虑籽粒产量和水分利用效率,拔节期灌水90 mm、施氮225 kg/hm2和拔节期灌水60 mm、施氮300 kg/hm2为产量和水分利用效率兼优的灌溉施肥组合。展开更多
The temporal behaviours of stimulated Rayleigh-wing scattering,at quasi-equilibrium and non-equilibrium of the molecular orientational distributions,are reported in this letter.The experimental results also show the r...The temporal behaviours of stimulated Rayleigh-wing scattering,at quasi-equilibrium and non-equilibrium of the molecular orientational distributions,are reported in this letter.The experimental results also show the relaxation time of molecular orientation in high alignment is longer than 80 picosecond.展开更多
The interaction of the electrons with the phonons in GaAs/AlGaAs quantum wells,quantum well wires,and quantum well boxes has been studied by meansuring their time resolved photoluminescence(PL)spectra.In the quantum w...The interaction of the electrons with the phonons in GaAs/AlGaAs quantum wells,quantum well wires,and quantum well boxes has been studied by meansuring their time resolved photoluminescence(PL)spectra.In the quantum well(Q W)system,relaxation time of the electron energy of the narrower well is shorter than that of the wider well.It is attributed to the stronger interaction of the electrons with the interface mode phonons.In the Q W wires and Q W boxes,the shortening of the relaxation time is obvious.It is due to the stronger electron-phonon interaction caused by the reduction of screening effect.Our experiments also demonstrated the incident laser intensity dependence of the relaxation time.展开更多
文摘The temporal behaviours of stimulated Rayleigh-wing scattering,at quasi-equilibrium and non-equilibrium of the molecular orientational distributions,are reported in this letter.The experimental results also show the relaxation time of molecular orientation in high alignment is longer than 80 picosecond.
文摘The interaction of the electrons with the phonons in GaAs/AlGaAs quantum wells,quantum well wires,and quantum well boxes has been studied by meansuring their time resolved photoluminescence(PL)spectra.In the quantum well(Q W)system,relaxation time of the electron energy of the narrower well is shorter than that of the wider well.It is attributed to the stronger interaction of the electrons with the interface mode phonons.In the Q W wires and Q W boxes,the shortening of the relaxation time is obvious.It is due to the stronger electron-phonon interaction caused by the reduction of screening effect.Our experiments also demonstrated the incident laser intensity dependence of the relaxation time.
