Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited.Modified fertilization management and planting density are ...Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited.Modified fertilization management and planting density are efficient methods for increasing crop yield.Field experiments were designed to investigate the influence of modified fertilization management and planting density on grain yield and nitrogen use efficiency of the popular maize variety Zhengdan 958, in four treatments including local farmer＇s practice（FP）, high-yielding and high efficiency cultivation（HH）, super high-yielding cultivation（SH）, and the control（CK）.Trials were conducted in three locations of the Huang-Huai-Hai Plain in northern China.Compared with FP, SH was clearly able to promote N absorption and dry matter accumulation in post-anthesis, and achieve high yield and N use efficiency by increasing planting density and postponing the supplementary application of fertilizers.However, with an increase in planting density, the demand of N increased along with grain yield.Due to the input of too much N fertilizer, the efficiency of N use in SH was low.Applying less total N, ameliorating cultivation and cropping management practices should be considered as priority strategies to augment production potential and finally achieve synchronization between high yield and high N efficiency in fertile soils.However, in situations where soil fertility is low, achieving high yield and high N use efficiency in maize will likely depend on increased planting density and appropriate application of supplementary fertilizers postpone to the grain-filling stage.展开更多
Nanostructured CeO_(2) thin films and powders are studied by high temperature x-ray photoelectron spectroscopy and thermal gravimetric analysis.The results indicate that the surface composition strongly depends on tem...Nanostructured CeO_(2) thin films and powders are studied by high temperature x-ray photoelectron spectroscopy and thermal gravimetric analysis.The results indicate that the surface composition strongly depends on temperature,the surface O/Ce ratio initially increases with increasing temperature,then decreases with the further increase of temperature,the maximum surface O/Ce ratio is at about 300℃.The variation of the surface composition with temperature arises from the ion migration,redistribution and transformation between lattice oxygen and gas phase oxygen near the grain boundaries during the thermodynamic equilibrium process.The results also show that CeO_(2) has a weakly bond oxygen,high oxygen mobility in the bulk and a high molecular dissociation rate at the surface,especially for the sol-gel prepared nanocrystallite CeO_(2).展开更多
The influence of doping lanthana on valent state of CeO_(2) surface has been studied by using x-ray photoelectron spectrascopy It was found that La^(3+) doping in host CeO_(2) lattice can promote to convert Ce^(4+) in...The influence of doping lanthana on valent state of CeO_(2) surface has been studied by using x-ray photoelectron spectrascopy It was found that La^(3+) doping in host CeO_(2) lattice can promote to convert Ce^(4+) into Ce^(3+) and enhance adsorbing-carbonyl capacity of the materials.However,the inversion of Ce^(4+) to Ce^(3+) is depressed by dopant La^(3+) during argon ion bombardment.展开更多
La-doping effects of strontium titanate(SrTiO_(3))thin films were studied by x-ray photoelectron spectroscopy.The results indicated that the oxygen adsorption properties of SrTiO_(3) thin film surface could be signifi...La-doping effects of strontium titanate(SrTiO_(3))thin films were studied by x-ray photoelectron spectroscopy.The results indicated that the oxygen adsorption properties of SrTiO_(3) thin film surface could be significantly affected by La substitution.Besides,a shoulder was observed on the high binding energy side of the main O_(1s),peak in La-doped thin films.展开更多
基金supported by grants from the National Natural Science Foundation of China(31371576,31071358,31301274)the European Union’s Seventh Framework Programme(NUE-CROPS 222645)+1 种基金the National Key Technology Support Program of China(2011BAD16B14,2012BAD04B05-2)the Special Fund for Agro-Scientific Research in the Public Interest of China(HY12031100,HY1203096)
文摘Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited.Modified fertilization management and planting density are efficient methods for increasing crop yield.Field experiments were designed to investigate the influence of modified fertilization management and planting density on grain yield and nitrogen use efficiency of the popular maize variety Zhengdan 958, in four treatments including local farmer＇s practice（FP）, high-yielding and high efficiency cultivation（HH）, super high-yielding cultivation（SH）, and the control（CK）.Trials were conducted in three locations of the Huang-Huai-Hai Plain in northern China.Compared with FP, SH was clearly able to promote N absorption and dry matter accumulation in post-anthesis, and achieve high yield and N use efficiency by increasing planting density and postponing the supplementary application of fertilizers.However, with an increase in planting density, the demand of N increased along with grain yield.Due to the input of too much N fertilizer, the efficiency of N use in SH was low.Applying less total N, ameliorating cultivation and cropping management practices should be considered as priority strategies to augment production potential and finally achieve synchronization between high yield and high N efficiency in fertile soils.However, in situations where soil fertility is low, achieving high yield and high N use efficiency in maize will likely depend on increased planting density and appropriate application of supplementary fertilizers postpone to the grain-filling stage.
基金Supported by the National Natural Science Foundation of China under Grant No.19874077。
文摘Nanostructured CeO_(2) thin films and powders are studied by high temperature x-ray photoelectron spectroscopy and thermal gravimetric analysis.The results indicate that the surface composition strongly depends on temperature,the surface O/Ce ratio initially increases with increasing temperature,then decreases with the further increase of temperature,the maximum surface O/Ce ratio is at about 300℃.The variation of the surface composition with temperature arises from the ion migration,redistribution and transformation between lattice oxygen and gas phase oxygen near the grain boundaries during the thermodynamic equilibrium process.The results also show that CeO_(2) has a weakly bond oxygen,high oxygen mobility in the bulk and a high molecular dissociation rate at the surface,especially for the sol-gel prepared nanocrystallite CeO_(2).
基金Supported by the National Natural Science Foundation of China under Grant No.19874077Ph.D.Educational Fund.
文摘The influence of doping lanthana on valent state of CeO_(2) surface has been studied by using x-ray photoelectron spectrascopy It was found that La^(3+) doping in host CeO_(2) lattice can promote to convert Ce^(4+) into Ce^(3+) and enhance adsorbing-carbonyl capacity of the materials.However,the inversion of Ce^(4+) to Ce^(3+) is depressed by dopant La^(3+) during argon ion bombardment.
基金Supported by the Ford-China R&D Fund No.0945106.
文摘La-doping effects of strontium titanate(SrTiO_(3))thin films were studied by x-ray photoelectron spectroscopy.The results indicated that the oxygen adsorption properties of SrTiO_(3) thin film surface could be significantly affected by La substitution.Besides,a shoulder was observed on the high binding energy side of the main O_(1s),peak in La-doped thin films.
