We demonstrate nearly i e V GaN0.03As0.97 /In0.09 Ga0.91As strain-compensated short-period superlattice solar cells by all solid-state molecular beam epitaxy. The optimal period thickness for the superlattice growth i...We demonstrate nearly i e V GaN0.03As0.97 /In0.09 Ga0.91As strain-compensated short-period superlattice solar cells by all solid-state molecular beam epitaxy. The optimal period thickness for the superlattice growth is achieved to realize high structural quality. Meanwhile, the annealing conditions are optimized to realize a pho- toluminescence （PL） at a low temperature. However, no PL signal is detected at room temperature, which could be reflected by a lower open-circuit voltage of the fabricated devices. The GaN0.03As0.97/In0.09Ga0.91As super- lattice solar cells show a reasonably-high short-circuit current density （Jsc） of over lOmA/cm2. Eurthermore, a concentration behavior is measured, which shows a linear relationship between Jsc and concentration ratios. The extrapolated ideality factor and saturated current density by the concentration action are in good agreement with that extracted by the dark case of the p-i-n diodes.展开更多
The influences of nitrogen content and austenitization temperature on Nb（C, N） precipitation in niobium micro-alloyed steels were studied by different methods： optical microscopy, tensile tests, scanning electron m...The influences of nitrogen content and austenitization temperature on Nb（C, N） precipitation in niobium micro-alloyed steels were studied by different methods： optical microscopy, tensile tests, scanning electron mi- croscopy, transmission electron microscopy, physicochemical phase analysis, and small-angle X-ray scattering. The results show that the strength of the steel with high nitrogen content is slightly higher than that of the steel with low nitrogen content. The increase in the nitrogen content does not result in the increase in the amount of Nb（C,N） precipitates, which mainly depends on the niobium content in the steel. The mass fraction of small-sized Nb（C, N） precipitates （1--10 nm） in the steel with high nitrogen content is less than that in the steel with low nitrogen con- tent. After austenitized at 1 150 ℃, a number of large cuboidal and needle-shaped particles are detected in the steel with high nitrogen content, whereas they dissolve after austenitized at 1 200 ℃ and the Nb（C,N） precipitates become finer in both steels. Furthermore, the results also show that part of the nitrogen in steel involves the formation of al- loyed cementite.展开更多
Cowpea (Vigna unguiculata (L.) Walp), a legume crop that is grown in the worldwide, provides beneficial proteins for human consumption and animal feeding. In comparison, Rapid N analyzer as traditional method, has bee...Cowpea (Vigna unguiculata (L.) Walp), a legume crop that is grown in the worldwide, provides beneficial proteins for human consumption and animal feeding. In comparison, Rapid N analyzer as traditional method, has been widely used to measure protein content through the percentage of total nitrogen in the seed’s grounded powder. Near-Infrared Reflectance (NIR) has commonly been used to measure protein content in soybean seeds using whole grain without the need of seed grinding, which makes it possible to obtain fast results at a lower cost-per-analysis than the traditional combustion method. The specific objective of this study is to test a rapid method for measuring cowpea seed protein content by the NIR analyzer comparing to the traditional rapid N analyzer. A total of 240 cowpea genotypes were used in this study, including six seed coat colors, black, blackeye, browneye, cream, pinkeye, and red with 40 cowpea genotypes. The results showed that a linear relationship exists between the NIR analyzer and the Rapid N analyzer in the six different color groups. The correlation efficiency (r) between the seed protein contents from NIR and Rapid N was higher for pinkeye seed (r = 0.867), blackeye (0.771), cream (0.729), browneye (0.700), and red (0.623), respectively, but lower for black seeds, indicating that the NIR analyzer can be used to measure protein content for cowpea seeds with the five types of seed coat except black. Overview, the cowpea seed protein content measured from the NIR analyzer showed a little higher seed protein content. A series of regression models with different seed coat color have been built to adjust to protein content of colorful cowpea seeds from the NIR analyzer. But, it is not recommended to use for black color seeds due to a very low correlation efficiency (r) value with 0.184.展开更多
Aims Ecological systems,especially soils,have been recently recognized as an important source of atmospheric nitric oxide(No).However,the study on the contribution of plants to atmospheric No budget is significantly l...Aims Ecological systems,especially soils,have been recently recognized as an important source of atmospheric nitric oxide(No).However,the study on the contribution of plants to atmospheric No budget is significantly lagged.The specific objectives of this study are to reveal the phylogenetic variation in No emission potential existing in various plant species and find out the possible leaf traits affecting No emission potential.Methods We measured No emission potential,leaf N and C content,C:N ratio,specific leaf area,net photosynthetic rate(Pn)and estimated photosynthetic N use efficiency(PNuE)of 88 plant species.Further investigation of the relationships between No emission potential and leaf traits were performed by simple linear regression analysis and pair-wise correlation coefficients analysis.Important Findingsmajor results are as follows:(1)No emission from plant species exhibited large variations,ranging from 0 to 41.7 nmol m^(−2) h^(−1),and the species frequency distributions of No emission potential could be fitted to a log-normal curve.(2)among 88 species,No emission potential was the highest in Podocarpus macrophyllus,but lowest in Zanthoxylum nitidum and Vernicia montana.(3)No emission potential has strong correlation to leaf N content,Pn and PNuE.The variations in No emission potential among diverse plant species may be closely related to leaf N level and net photosynthetic ability.展开更多
A located field experiment was carried out to study the effects of different amount of chemical fertilizer usage on rice yield,economic benefits of rice,soil carbon（C） and total nitrogen（TN） under ploughing back o...A located field experiment was carried out to study the effects of different amount of chemical fertilizer usage on rice yield,economic benefits of rice,soil carbon（C） and total nitrogen（TN） under ploughing back of Chinese milk vetch for 5consecutive years.Six treatments were included in the experiment,they are CK（unfertilized）,CF（100% chemical fertilizer with the amount of N,P2O5,K2 O being150,75,120 kg/hm^2respectively）,A1（22 500 kg/hm^2 Chinese milk vetch and 100%chemical fertilizer）,A2（Chinese milk vetch and 80% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A3（Chinese milk vetch and 60% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A4（Chinese milk vetch and 40% nitrogen and potassium fertilizer and 100% phosphate fertilizer）.The results were as follows：application of fertilizer could increase the yield of rice,while Chinese milk vetch combined with fertilizer application had a much more increase effect in rice yield.Under the condition of milk vetch application with 22 500 kg/hm^2,the early rice yield of the treatment A1 was significantly increased by 7.7% compared with that of CF.And the yield of treatment A3 was basically identical to or slight increase in comparison with that of CF.Decreasing amount of fertilizers cloud improve output value of rice in the case of the utilization of Chinese milk vetch.The treatment A1 increased output value of rice by 5.92% in comparison of CF,and treatment A2 was by 4.08% in the next.Treatment A4 showed much better effect in increasing soil organic carbon and total nitrogen in the paddy soil than those of treatments applying mineral fertilizer only.There was a significant reduction on soil organic carbon and TN in treatment A2 in comparison with that of CF.In general,amount of application of milk vetch with 22 500 kg/hm^2 could replace chemical fertilizer partially,it also could improve rice yield,decrease the production cost,and raise the utilization efficiency of nutrients.展开更多
Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance ...Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance N utilization efficiency and minimize reactive N losses.However,the agronomic mechanisms through which green manure incorporation affects soil N retention and N loss under reduced N application remain unclear.This study aimed to uncover the compensatory mechanisms of green manure in improving wheat yield and N utilization under reduced N application,and to identify the principles behind reduced N loss in wheat fields.We conducted a split-plot experiment in the Hexi Oasis irrigation area of Northwest China from 2019 to 2024,using two cropping systems(W,fallow after wheat;W-G,green manure returning after wheat)combined with three N application levels(N1,local conventional N application rate;N2,N-reduction 15%;N3,N-reduction 30%).Our results demonstrated that green manure returning improved soil quality and compensated for the yield and N use efficiency losses caused by 15%chemical N reduction.Specifically,compared to the W-N1,W-GN2 increased soil organic matter content and soil water content by 6.5%and 9.4%,respectively,while reducing soil bulk density and pH by 8.9%and 6.7%.Meanwhile,W-GN2 increased soil nitrate N and total N content in the 0–40 cm soil layer by 8.4%and 8.7%,respectively.Moreover,W-GN2 reduced NH3 volatilization by 13.8%,N_(2)O emissions by 8.8%,and N leaching by 9.4%.It also enhanced microbial biomass N by 50.7%,urease activity by 10.2%,and decreased nitrate and nitrite reductase activities by 19.9%and 32.6%,respectively.Additionally,W-GN2 improved soil bacterialα-diversity and increased the abundance of functional bacteria.Green manure can sustain wheat yield and improve N utilization efficiency under reduced chemical N input by improving the soil environment,enhancing soil N retention and minimizing N losses,which presents a sustainable,yield-stabilizing strategy for Oasis agroecosystems in northwestern China.展开更多
The high-N-content, the cup-stacking and the macroscopic nitrogen doped carbon nanotubes（NCNT）were synthesized via an easily manufactured catalytic chemical vapor deposition（CCVD） method. Nitrogen physisorption, t...The high-N-content, the cup-stacking and the macroscopic nitrogen doped carbon nanotubes（NCNT）were synthesized via an easily manufactured catalytic chemical vapor deposition（CCVD） method. Nitrogen physisorption, transmission electron microscopy（TEM）, thermogravimetric analysis（TGA）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS） were used to characterize the as-obtained NCNTs. High reaction temperatures were found to be the key point to the formation of inner-cup-stacking NCNTs. However, the synthesis of the outer-cup-stacking NCNT needs special demands not only to the reaction temperature but also to the catalyst and the carrier gas. The possibility of CO oxidation by NCNT was proved to be very small, and the outer-cup-stacking NCNT showed obvious advantage in the oxidative dehydrogenation（ODH） of butene to butadiene compared to a bamboo-like NCNT with an even higher N content.展开更多
The microstructure and mechanical properties of Ti(C, N)-based cermets with different content Mo were studied. Different Mo contents were added into Ti(C, N)-based cermets. Effect of sintering temperature on mechanica...The microstructure and mechanical properties of Ti(C, N)-based cermets with different content Mo were studied. Different Mo contents were added into Ti(C, N)-based cermets. Effect of sintering temperature on mechanical properties of the cermets was also investigated. Specimens were fabricated by conventional powder metallurgy techniques and vacuum sintered at different temperatures. The microstructure and the fracture morphology were investigated using scanning electron microscope. Transverse strength and hardness were measured. The results show that the microstructure is uniform and the thickness of rim phase is moderate when the content of Mo is 8%. The mechanical properties are the best when the content of Mo is 8% and the sintering temperature is 1450℃.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 61274134the University of Science and Technology Beijing Talents Start-up Program under Grant No 06105033the International Cooperation Projects of Suzhou City under Grant No SH201215
文摘We demonstrate nearly i e V GaN0.03As0.97 /In0.09 Ga0.91As strain-compensated short-period superlattice solar cells by all solid-state molecular beam epitaxy. The optimal period thickness for the superlattice growth is achieved to realize high structural quality. Meanwhile, the annealing conditions are optimized to realize a pho- toluminescence （PL） at a low temperature. However, no PL signal is detected at room temperature, which could be reflected by a lower open-circuit voltage of the fabricated devices. The GaN0.03As0.97/In0.09Ga0.91As super- lattice solar cells show a reasonably-high short-circuit current density （Jsc） of over lOmA/cm2. Eurthermore, a concentration behavior is measured, which shows a linear relationship between Jsc and concentration ratios. The extrapolated ideality factor and saturated current density by the concentration action are in good agreement with that extracted by the dark case of the p-i-n diodes.
基金Item Sponsored by the CITIC-CBMM Niobium Steel Research and Development Program of China(2013-D065)
文摘The influences of nitrogen content and austenitization temperature on Nb（C, N） precipitation in niobium micro-alloyed steels were studied by different methods： optical microscopy, tensile tests, scanning electron mi- croscopy, transmission electron microscopy, physicochemical phase analysis, and small-angle X-ray scattering. The results show that the strength of the steel with high nitrogen content is slightly higher than that of the steel with low nitrogen content. The increase in the nitrogen content does not result in the increase in the amount of Nb（C,N） precipitates, which mainly depends on the niobium content in the steel. The mass fraction of small-sized Nb（C, N） precipitates （1--10 nm） in the steel with high nitrogen content is less than that in the steel with low nitrogen con- tent. After austenitized at 1 150 ℃, a number of large cuboidal and needle-shaped particles are detected in the steel with high nitrogen content, whereas they dissolve after austenitized at 1 200 ℃ and the Nb（C,N） precipitates become finer in both steels. Furthermore, the results also show that part of the nitrogen in steel involves the formation of al- loyed cementite.
文摘Cowpea (Vigna unguiculata (L.) Walp), a legume crop that is grown in the worldwide, provides beneficial proteins for human consumption and animal feeding. In comparison, Rapid N analyzer as traditional method, has been widely used to measure protein content through the percentage of total nitrogen in the seed’s grounded powder. Near-Infrared Reflectance (NIR) has commonly been used to measure protein content in soybean seeds using whole grain without the need of seed grinding, which makes it possible to obtain fast results at a lower cost-per-analysis than the traditional combustion method. The specific objective of this study is to test a rapid method for measuring cowpea seed protein content by the NIR analyzer comparing to the traditional rapid N analyzer. A total of 240 cowpea genotypes were used in this study, including six seed coat colors, black, blackeye, browneye, cream, pinkeye, and red with 40 cowpea genotypes. The results showed that a linear relationship exists between the NIR analyzer and the Rapid N analyzer in the six different color groups. The correlation efficiency (r) between the seed protein contents from NIR and Rapid N was higher for pinkeye seed (r = 0.867), blackeye (0.771), cream (0.729), browneye (0.700), and red (0.623), respectively, but lower for black seeds, indicating that the NIR analyzer can be used to measure protein content for cowpea seeds with the five types of seed coat except black. Overview, the cowpea seed protein content measured from the NIR analyzer showed a little higher seed protein content. A series of regression models with different seed coat color have been built to adjust to protein content of colorful cowpea seeds from the NIR analyzer. But, it is not recommended to use for black color seeds due to a very low correlation efficiency (r) value with 0.184.
基金This study was financially supported by the Natural Science Foundation of China(NSFC)(31300505,31260057,30930076,30670317)Research Fund of State Key Laboratory of Soil and Sustainable Agriculture,Nanjing Institute of Soil Science,Chinese Academy of Science(Y412201449)+1 种基金China Postdoctoral Science Foundation(2012M521278)the Scholarship Award for Excellent Doctoral Student granted by the Chinese Ministry of Education.
文摘Aims Ecological systems,especially soils,have been recently recognized as an important source of atmospheric nitric oxide(No).However,the study on the contribution of plants to atmospheric No budget is significantly lagged.The specific objectives of this study are to reveal the phylogenetic variation in No emission potential existing in various plant species and find out the possible leaf traits affecting No emission potential.Methods We measured No emission potential,leaf N and C content,C:N ratio,specific leaf area,net photosynthetic rate(Pn)and estimated photosynthetic N use efficiency(PNuE)of 88 plant species.Further investigation of the relationships between No emission potential and leaf traits were performed by simple linear regression analysis and pair-wise correlation coefficients analysis.Important Findingsmajor results are as follows:(1)No emission from plant species exhibited large variations,ranging from 0 to 41.7 nmol m^(−2) h^(−1),and the species frequency distributions of No emission potential could be fitted to a log-normal curve.(2)among 88 species,No emission potential was the highest in Podocarpus macrophyllus,but lowest in Zanthoxylum nitidum and Vernicia montana.(3)No emission potential has strong correlation to leaf N content,Pn and PNuE.The variations in No emission potential among diverse plant species may be closely related to leaf N level and net photosynthetic ability.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201103005-08)National Science and Technology Support Program during the 12thFive-year Plan(2012BAD05B05-3)International Plant Nutrition Institute S&T Program(Hunan-16)~~
文摘A located field experiment was carried out to study the effects of different amount of chemical fertilizer usage on rice yield,economic benefits of rice,soil carbon（C） and total nitrogen（TN） under ploughing back of Chinese milk vetch for 5consecutive years.Six treatments were included in the experiment,they are CK（unfertilized）,CF（100% chemical fertilizer with the amount of N,P2O5,K2 O being150,75,120 kg/hm^2respectively）,A1（22 500 kg/hm^2 Chinese milk vetch and 100%chemical fertilizer）,A2（Chinese milk vetch and 80% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A3（Chinese milk vetch and 60% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A4（Chinese milk vetch and 40% nitrogen and potassium fertilizer and 100% phosphate fertilizer）.The results were as follows：application of fertilizer could increase the yield of rice,while Chinese milk vetch combined with fertilizer application had a much more increase effect in rice yield.Under the condition of milk vetch application with 22 500 kg/hm^2,the early rice yield of the treatment A1 was significantly increased by 7.7% compared with that of CF.And the yield of treatment A3 was basically identical to or slight increase in comparison with that of CF.Decreasing amount of fertilizers cloud improve output value of rice in the case of the utilization of Chinese milk vetch.The treatment A1 increased output value of rice by 5.92% in comparison of CF,and treatment A2 was by 4.08% in the next.Treatment A4 showed much better effect in increasing soil organic carbon and total nitrogen in the paddy soil than those of treatments applying mineral fertilizer only.There was a significant reduction on soil organic carbon and TN in treatment A2 in comparison with that of CF.In general,amount of application of milk vetch with 22 500 kg/hm^2 could replace chemical fertilizer partially,it also could improve rice yield,decrease the production cost,and raise the utilization efficiency of nutrients.
基金financial support of the Science and Technology Program in Gansu province(25JRRA347,24ZDNA008)the Natural Science Foundation of China(32372238,U21A20218,32460547)+4 种基金the Industrial Support Project of Educational Committee of Gansu province(2025CYZC-037)the Research Program Sponsored by State Key Laboratory of Aridland Crop Science(GSCS-2023-Z03)the Agricultural Research System of China(CARS-22-G-12)China Agricultural University Corresponding Support Research Joint Fund(GSAU-DKZY-2024-001)the UPTAKE Project on EU Horizon(101081521).
文摘Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance N utilization efficiency and minimize reactive N losses.However,the agronomic mechanisms through which green manure incorporation affects soil N retention and N loss under reduced N application remain unclear.This study aimed to uncover the compensatory mechanisms of green manure in improving wheat yield and N utilization under reduced N application,and to identify the principles behind reduced N loss in wheat fields.We conducted a split-plot experiment in the Hexi Oasis irrigation area of Northwest China from 2019 to 2024,using two cropping systems(W,fallow after wheat;W-G,green manure returning after wheat)combined with three N application levels(N1,local conventional N application rate;N2,N-reduction 15%;N3,N-reduction 30%).Our results demonstrated that green manure returning improved soil quality and compensated for the yield and N use efficiency losses caused by 15%chemical N reduction.Specifically,compared to the W-N1,W-GN2 increased soil organic matter content and soil water content by 6.5%and 9.4%,respectively,while reducing soil bulk density and pH by 8.9%and 6.7%.Meanwhile,W-GN2 increased soil nitrate N and total N content in the 0–40 cm soil layer by 8.4%and 8.7%,respectively.Moreover,W-GN2 reduced NH3 volatilization by 13.8%,N_(2)O emissions by 8.8%,and N leaching by 9.4%.It also enhanced microbial biomass N by 50.7%,urease activity by 10.2%,and decreased nitrate and nitrite reductase activities by 19.9%and 32.6%,respectively.Additionally,W-GN2 improved soil bacterialα-diversity and increased the abundance of functional bacteria.Green manure can sustain wheat yield and improve N utilization efficiency under reduced chemical N input by improving the soil environment,enhancing soil N retention and minimizing N losses,which presents a sustainable,yield-stabilizing strategy for Oasis agroecosystems in northwestern China.
基金financial support from the National Natural Science Foundation of China(Nos.21133010,21473223,51221264,21261160487,21411130120,21503241,91545119 and 91545110)the“Strategic Priority Research Program”of the Chinese Academy of Sciences(Grant No.XDA09030103)the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘The high-N-content, the cup-stacking and the macroscopic nitrogen doped carbon nanotubes（NCNT）were synthesized via an easily manufactured catalytic chemical vapor deposition（CCVD） method. Nitrogen physisorption, transmission electron microscopy（TEM）, thermogravimetric analysis（TGA）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS） were used to characterize the as-obtained NCNTs. High reaction temperatures were found to be the key point to the formation of inner-cup-stacking NCNTs. However, the synthesis of the outer-cup-stacking NCNT needs special demands not only to the reaction temperature but also to the catalyst and the carrier gas. The possibility of CO oxidation by NCNT was proved to be very small, and the outer-cup-stacking NCNT showed obvious advantage in the oxidative dehydrogenation（ODH） of butene to butadiene compared to a bamboo-like NCNT with an even higher N content.
文摘The microstructure and mechanical properties of Ti(C, N)-based cermets with different content Mo were studied. Different Mo contents were added into Ti(C, N)-based cermets. Effect of sintering temperature on mechanical properties of the cermets was also investigated. Specimens were fabricated by conventional powder metallurgy techniques and vacuum sintered at different temperatures. The microstructure and the fracture morphology were investigated using scanning electron microscope. Transverse strength and hardness were measured. The results show that the microstructure is uniform and the thickness of rim phase is moderate when the content of Mo is 8%. The mechanical properties are the best when the content of Mo is 8% and the sintering temperature is 1450℃.
