The positron lifetime spectra and ionic conductivity have been measured for polymeric electrolyte PEU LiClO_(4)as a function of temperature in the range of 120￣360 K and as a function of Li salt concentration at room...The positron lifetime spectra and ionic conductivity have been measured for polymeric electrolyte PEU LiClO_(4)as a function of temperature in the range of 120￣360 K and as a function of Li salt concentration at room temperature.From the temperature dependence of positron annihilation parameters,the glass transition and subtransition are observed,and the glass transition temperature T_(g)of pure PEU is determined to be 240 K.Above T_(g),the free volume hole size dramatically increases with temperature.The variations of positron annihilation parameters and ionic conductivities with respect to Li salt concentration at room temperature indicate that the Li salt mainly diffuses into the amorphous region in PEU LiClO_(4).The increase of Li salt concentration brings about an increase in the number of carried ions,and a reduction of the fractional free volume.展开更多
The relationships between irradiation doses of γ ray and the main photoelectric characteristics of PIN photodiode or conventional photodiode with different structure were studied. The experimental results show that a...The relationships between irradiation doses of γ ray and the main photoelectric characteristics of PIN photodiode or conventional photodiode with different structure were studied. The experimental results show that after the photodiodes being irradiated,the photocurrent decreases,especially for short wavelength of light. The dark current of the photodiodes with smaller active area decreases while increases for that with larger active area,and the response time shortens. The plane scanning experiment of laser beam indicates that the homogeneity of the device's surface is not influenced by the irradiation. The results prove that PIN photodiode shows relatively good radioresistance.展开更多
【目的】以紧凑型玉米品种先玉335为供试作物,研究地膜覆盖、施氮量、种植密度及其互作对春玉米氮素吸收转运及利用效率的影响,以期为黄土高原半干旱区春玉米高产高效栽培提供理论依据。【方法】2013—2014年春玉米生长季,设置覆盖方式...【目的】以紧凑型玉米品种先玉335为供试作物,研究地膜覆盖、施氮量、种植密度及其互作对春玉米氮素吸收转运及利用效率的影响,以期为黄土高原半干旱区春玉米高产高效栽培提供理论依据。【方法】2013—2014年春玉米生长季,设置覆盖方式(覆膜和不覆膜)、施氮量(2013年为0、170、200和230 kg N·hm^(-2),2014年为0、170、225和280 kg N·hm^(-2))和种植密度(5.0×10~4、6.5×10~4和8.0×10~4株/hm^2)3个因子,分析不同处理的氮素累积与转运、产量及氮肥生产效率。【结果】地膜覆盖显著增加了玉米吐丝前氮素累积量,促进了吐丝后氮素累积和吐丝前累积氮素的再转移,从而显著提高了籽粒氮素累积量和籽粒产量。覆盖方式与氮肥或密度互作显著影响春玉米氮素吸收、累积和转移。地膜覆盖条件下更多的氮肥(200—230 kg N·hm^(-2))或更高的密度(6.5×10~4—8.0×10~4株/hm^2)投入能有效促进吐丝前储存更多的氮素向籽粒转运,提高吐丝后期氮同化量及其对籽粒的贡献率,从而提高了籽粒氮素累积量;而不覆盖条件下当施氮量超过170 kg N·hm^(-2)或密度超过5.0×104株/hm^2时,吐丝后氮同化量及其对籽粒的贡献显著减少,从而导致吐丝前氮素储备的增加未能有效增加籽粒氮素累积。氮肥与密度互作显著影响氮素累积、吸收和转移。氮肥偏生产力(PFPN)和氮素收获指数(NHI)与吐丝前氮素累积量、氮素转移量、吐丝后氮素累积量及籽粒产量呈正相关,达到了显著水平。从春玉米氮素累积、转移及与产量和氮肥偏生产力关系看,全膜双垄沟播种植技术的合理施氮量为200—230 kg N·hm^(-2)、密度为8.0×10~4株/hm^2,其产量可达13.7—14.6 t·hm^(-2),PFPN可达64.8—68.7 kg·kg^(-1)。【结论】地膜覆盖与适宜的施氮量和种植密度相结合的综合管理实践,有利于促进灌浆期营养器官储存氮向籽粒转移和吐丝后氮同化的协同增加,从而实现高产和高氮肥生产力。展开更多
文摘The positron lifetime spectra and ionic conductivity have been measured for polymeric electrolyte PEU LiClO_(4)as a function of temperature in the range of 120￣360 K and as a function of Li salt concentration at room temperature.From the temperature dependence of positron annihilation parameters,the glass transition and subtransition are observed,and the glass transition temperature T_(g)of pure PEU is determined to be 240 K.Above T_(g),the free volume hole size dramatically increases with temperature.The variations of positron annihilation parameters and ionic conductivities with respect to Li salt concentration at room temperature indicate that the Li salt mainly diffuses into the amorphous region in PEU LiClO_(4).The increase of Li salt concentration brings about an increase in the number of carried ions,and a reduction of the fractional free volume.
文摘The relationships between irradiation doses of γ ray and the main photoelectric characteristics of PIN photodiode or conventional photodiode with different structure were studied. The experimental results show that after the photodiodes being irradiated,the photocurrent decreases,especially for short wavelength of light. The dark current of the photodiodes with smaller active area decreases while increases for that with larger active area,and the response time shortens. The plane scanning experiment of laser beam indicates that the homogeneity of the device's surface is not influenced by the irradiation. The results prove that PIN photodiode shows relatively good radioresistance.
文摘【目的】以紧凑型玉米品种先玉335为供试作物,研究地膜覆盖、施氮量、种植密度及其互作对春玉米氮素吸收转运及利用效率的影响,以期为黄土高原半干旱区春玉米高产高效栽培提供理论依据。【方法】2013—2014年春玉米生长季,设置覆盖方式(覆膜和不覆膜)、施氮量(2013年为0、170、200和230 kg N·hm^(-2),2014年为0、170、225和280 kg N·hm^(-2))和种植密度(5.0×10~4、6.5×10~4和8.0×10~4株/hm^2)3个因子,分析不同处理的氮素累积与转运、产量及氮肥生产效率。【结果】地膜覆盖显著增加了玉米吐丝前氮素累积量,促进了吐丝后氮素累积和吐丝前累积氮素的再转移,从而显著提高了籽粒氮素累积量和籽粒产量。覆盖方式与氮肥或密度互作显著影响春玉米氮素吸收、累积和转移。地膜覆盖条件下更多的氮肥(200—230 kg N·hm^(-2))或更高的密度(6.5×10~4—8.0×10~4株/hm^2)投入能有效促进吐丝前储存更多的氮素向籽粒转运,提高吐丝后期氮同化量及其对籽粒的贡献率,从而提高了籽粒氮素累积量;而不覆盖条件下当施氮量超过170 kg N·hm^(-2)或密度超过5.0×104株/hm^2时,吐丝后氮同化量及其对籽粒的贡献显著减少,从而导致吐丝前氮素储备的增加未能有效增加籽粒氮素累积。氮肥与密度互作显著影响氮素累积、吸收和转移。氮肥偏生产力(PFPN)和氮素收获指数(NHI)与吐丝前氮素累积量、氮素转移量、吐丝后氮素累积量及籽粒产量呈正相关,达到了显著水平。从春玉米氮素累积、转移及与产量和氮肥偏生产力关系看,全膜双垄沟播种植技术的合理施氮量为200—230 kg N·hm^(-2)、密度为8.0×10~4株/hm^2,其产量可达13.7—14.6 t·hm^(-2),PFPN可达64.8—68.7 kg·kg^(-1)。【结论】地膜覆盖与适宜的施氮量和种植密度相结合的综合管理实践,有利于促进灌浆期营养器官储存氮向籽粒转移和吐丝后氮同化的协同增加,从而实现高产和高氮肥生产力。
