At a rice wheat rotational free air CO 2 enrichment(FACE) platform, the effect of elevated atmospheric CO 2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmosp...At a rice wheat rotational free air CO 2 enrichment(FACE) platform, the effect of elevated atmospheric CO 2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO 2(ambient 370 μl/L + 200 μl/L). 32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effect of elevated atmospheric CO 2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO 2 may indicate the change of soil food web.展开更多
A hydroponics experiment was conducted to investigate the rice root growth in FACE （free-air carbon dioxide enrichment）. The root biomass, root volume, ratio of root/shoot, number of adventitious roots and root diam...A hydroponics experiment was conducted to investigate the rice root growth in FACE （free-air carbon dioxide enrichment）. The root biomass, root volume, ratio of root/shoot, number of adventitious roots and root diameter significantly increased under FACE conditions, while the CO2 enrichment decreased the N concentration in rice roots without any change in the C content, leading to an increase in root C：N ratio. Moreover, the elevated CO2 resulted in a remarkable decrease of root activity, expressed as per unit root dry weight, which might be responsible for decreased N concentration in roots.展开更多
Mammography x-rays standard is required to improve the quality of mammary machine and reduce the dose for w omen and staff. The molybdenum target x-rays machine is used as the radiation source and free-air cylindrical...Mammography x-rays standard is required to improve the quality of mammary machine and reduce the dose for w omen and staff. The molybdenum target x-rays machine is used as the radiation source and free-air cylindrical chamber is designed for detecting photon. Four standard radiation qualities are established w ith international standard documents as references. The Correction factors including air attenuation,scattered radiation,fluorescence,w all transmission,electron loss are studied in the four radiation quality. The uncertainty in absolute measurement of air-kerma includes air volume measurement of ionization chambers,current measurement,measurement of temperature and pressure,measurement of correction factors,physical constants and orientation of the reference distance. The relative combined standard uncertainty is 0.24%.展开更多
Free air CO2 enrichment(FACE) and nitrogen(N) have marked effects on rice root growth,and numerical simulation can explain these effects. To further define the effects of FACE on root growth of rice, an experiment was...Free air CO2 enrichment(FACE) and nitrogen(N) have marked effects on rice root growth,and numerical simulation can explain these effects. To further define the effects of FACE on root growth of rice, an experiment was performed, using the hybrid indica cultivar Xianyou63. The effects of increasing atmospheric CO2 concentration [CO2], 200 μmol mol-1higher than ambient, on the growth of rice adventitious roots were evaluated, with two levels of N: low(LN, 125 kg ha-1) and normal(NN, 250 kg ha-1). The results showed a significant increase in both adventitious root number(ARN) and adventitious root length(ARL) under FACE treatment. The application of nitrogen also increased ARN and ARL, but these increases were smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root number and length were constructed with time as the driving factor. The models illustrated the dynamic development of rice adventitious root number and length after transplanting, regulated either by atmospheric [CO2] or by N application.The simulation result was supported by statistical tests comparing experimental data from different years, and the model yields realistic predictions of root growth. These results suggest that the models have strong predictive potential under conditions of atmospheric [CO2] rises in the future.展开更多
Elevated atmospheric CO2 can influence soil C dynamics in agroecosystems. The effects of free-air CO2 enrichment （FACE） and N fertilization on soil organic C （Corg）, dissolved organic C （DOC）, microbial biomass...Elevated atmospheric CO2 can influence soil C dynamics in agroecosystems. The effects of free-air CO2 enrichment （FACE） and N fertilization on soil organic C （Corg）, dissolved organic C （DOC）, microbial biomass C （Cmic） and soil basal respiration （SBR） were investigated in a Chinese wheat field after expose to elevated CO2 for four full years. The results indicated that elevated CO2 has stimulative effects on soil C concentrations regardless of N fertilization. Following the elevated CO2, the concentrations of Corg and SBR were increased at wheat jointing stage, and those of DOC and Cmic were enhanced obviously across the wheat jointing stage and the fallow period after wheat harvest. On the other hand, N fertilization did not significantly affect the content of soil C. Significant correlations were found among DOC, Cmic, and SBR in this study.展开更多
铜线表面钯层特征是影响芯片封装过程中烧球和键合质量的重要因素。采用无卤直接涂镀工艺,制备了不同涂镀速度和涂镀温度下的镀钯铜线,研究了涂镀速度对镀层形貌和无空气焊球(free air ball,FAB)特征的影响。结果表明:随着涂镀速度增加...铜线表面钯层特征是影响芯片封装过程中烧球和键合质量的重要因素。采用无卤直接涂镀工艺,制备了不同涂镀速度和涂镀温度下的镀钯铜线,研究了涂镀速度对镀层形貌和无空气焊球(free air ball,FAB)特征的影响。结果表明:随着涂镀速度增加,涂镀时间减少,钯颗粒在铜线表面分布的均匀性变差,局部分布不均匀的钯颗粒团聚引起钯颗粒浓度较高,镀层表面钯颗粒团聚区域增加。在涂镀速度50 m/min下,镀层表面钯分布较为均匀。随着涂镀速度的增加,FAB球直径逐渐减小;镀钯铜线表面Pd颗粒团聚区域和未团聚区域的钯含量差增大,FAB球尺寸的一致性逐渐下降。在较低涂镀速度50 m/min下,FAB球表面钯分布比较均匀;在较高的涂镀速度100 m/min下,镀层表面大量团聚的钯颗粒重熔后在FAB球表面呈大面积连续的富钯区,钯再分布的均匀性较差。从FAB球尺寸的一致性和表面钯再分布的均匀性方面考虑,涂镀速度50 m/min和涂镀温度400℃为镀钯铜线涂镀较佳的工艺参数。展开更多
Background:Increasing atmospheric[CO_(2)]can increase photosynthesis and promote plant growth,consequently influencing nitrogen(N)cycling.Yet,there is no systematic information on the N response among different organs...Background:Increasing atmospheric[CO_(2)]can increase photosynthesis and promote plant growth,consequently influencing nitrogen(N)cycling.Yet,there is no systematic information on the N response among different organs of japonica and indica rice genotypes to elevated[CO_(2)]as affected by N application.To investigate the impacts of elevated[CO_(2)]and N fertilization on N uptake and utilization of different genotypic rice(Oryza sativa L.)during grain filling,a free-air CO_(2) enrichment(FACE)experiment with indica cv.Liangyou 084(IIY084)and japonica cv.Wuyunjing 23(WYJ23)was conducted in Eastern China.Crops were exposed to ambient[CO_(2)]and elevated[CO_(2)](200μmol mol^(−1) above ambient)at two levels of N:control(0N)and 22.5 g N m^(−2)(normal N,NN),and they were sampled at 82 days after transplanting(DAT),99 DAT,and maturity,respectively.Results:Under FACE,significant declines of N concentration in all tissues and the whole plants were observed with the greater decrease in leaves and stems at three stages.Positive responses of N use efficiency(NUE)to elevated[CO_(2)]were recorded over the study period.The total N accumulation remained unchanged,while a large amount of N was partitioned to panicles at the expense of leaves and stems.As compared to WYJ23,greater N transportation from roots to aboveground,especially the panicles,was observed on IIY084 accompanied by higher panicle biomass(82 DAT and 99 DAT),N concentrations(maturity),and greater NUE for leaves through the study season.Across all[CO_(2)]and cultivars,N fertilization increased N partitioning to leaves and stems while decreasing that to panicles.Additionally,N supply decreased NUE while stimulating N concentrations and N amounts of rice plants.Among all treatments,IIY084 had the highest N accumulation and allocation in panicles under elevated[CO_(2)]in combination with N fertilizer at maturity.Conclusion:Data from this study were helpful for understanding the temporal N uptake and utilization of different rice genotypes as affected by N availability and suggest that IIY084 promises a considerable prospect for its grain yield and quality under future elevated atmospheric[CO_(2)].展开更多
A free-air ionization chamber in low-energy X-ray has been designed and manufactured at the National Institute of Metrology （NIM, China） according to the defination of air-kerma. The results of a preliminary test sh...A free-air ionization chamber in low-energy X-ray has been designed and manufactured at the National Institute of Metrology （NIM, China） according to the defination of air-kerma. The results of a preliminary test show that the leakage current of ionization chamber is around 2×10^-15A, and the correction factor of ion recombination for the ionization chamber is also obtained. The free-air ionization chamber is suitable for the primary standard in low-energy X-rays.展开更多
The responses of rice to the second degree contamination of copper were studied by pot experiments under free-air CO2 enrichment (FACE) with 570 μmol·mol-1 of CO2. The results showed that the content of copper i...The responses of rice to the second degree contamination of copper were studied by pot experiments under free-air CO2 enrichment (FACE) with 570 μmol·mol-1 of CO2. The results showed that the content of copper in rice leaves was reduced with the CO2 concentration reaching 570 μmol·mol-1 and this happened more significantly under the second degree contamination of copper. Under FACE, activities of superoxide dismutase (SOD) enzyme in rice leaves treated by copper contamination were induced, whereas the contents of glutathione (GSH) and glutathione disulfide (GSSG) had no significant difference from the control. In the presence of ambient CO2, activities of SOD enzyme treated by copper pollution were suppressed during the whole rice growth, however, the contents of GSH and GSSG were induced at tillering and jointing stages, and then restored to the control levels in later growth under the second degree contamination of copper. With the rice growing, the content of malondialdehyde (MDA) rises continuously, but there had been no significant difference between the treatments at the same growth stage. Further studies are needed on the response mechanism of rice to Cu stress under elevated CO2.展开更多
Elevated atmospheric carbon dioxide concentration([CO_(2)])can stimulate crop growth and increase yield,but the effect may be constrained by soil contamination with heavy metals.In a free-air carbon dioxide enrichment...Elevated atmospheric carbon dioxide concentration([CO_(2)])can stimulate crop growth and increase yield,but the effect may be constrained by soil contamination with heavy metals.In a free-air carbon dioxide enrichment experiment over three seasons,we found that soil heavy metal contamination can constrain or even reverse the projected CO_(2)fertilization effect on rice yield.Elevated[CO_(2)]produced opposing effects on the accumulation of arsenic and cadmium in rice grain.Breeding crops for heavy-metal resistance and low arsenic accumulation may become necessary with continuing climate change.展开更多
人类活动导致的大气和气候变化将极大地改变作物的生长环境,其中最大的一个变化就是大气二氧化碳(CO2)浓度的迅速上升:从工业革命前的平均270μmol/mol上升到目前的381μmol/mol,到2050年至少超过550μmol/mol。FACE(Free-air CO2 enric...人类活动导致的大气和气候变化将极大地改变作物的生长环境,其中最大的一个变化就是大气二氧化碳(CO2)浓度的迅速上升:从工业革命前的平均270μmol/mol上升到目前的381μmol/mol,到2050年至少超过550μmol/mol。FACE(Free-air CO2 enrichment,开放式空气中CO2浓度增高)试验是目前评估未来高浓度CO2对作物生长和产量实际影响的最佳方法。水稻无疑是人类最重要的食物来源,迄今为止人类利用FACE技术开展水稻响应和适应的研究已有10a(19982008年)的历史。以生长发育为主线,首次系统综述了10a水稻FACE试验在该领域的研究成果,总结了FACE情形下高浓度CO2(模拟本世纪中叶大气CO2浓度)对主要供试水稻品种(小区面积大于4m2)光合作用、生育进程、地上部生长、地下部生长、物质分配、籽粒灌浆、产量构成以及倒伏性状等影响的研究进展,比较了FACE与非FACE研究之间以及中国和日本FACE研究(世界上唯一的两个大型水稻FACE研究)之间的异同点。根据研究进展以及当前的技术水平,文章最后提出了该领域的3个优先课题:(1)FACE情形下杂交稻生产力响应高于预期的生物学机制;(2)FACE情形下CO2与主要栽培措施的互作效应;(3)FACE情形下CO2与主要空气污染物臭氧的互作效应。这些响应的机理性解析将有助于从根本上减少人类预测未来粮食安全的不确定性,进而更加有效地制订出应对全球变化的适应策略。展开更多
文摘At a rice wheat rotational free air CO 2 enrichment(FACE) platform, the effect of elevated atmospheric CO 2 on soil nematode communities in a farmland ecosystem was studied. Wheat plots were exposed to elevated atmospheric CO 2(ambient 370 μl/L + 200 μl/L). 32 families and 40 genera of nematode were observed in soil suspensions during the study period. Under FACE treatment, the numbers of total nematodes, bacterivores and fungivores exhibited an increasing trend. Because of the seasonal variation of soil temperature and moisture, the effect of elevated atmospheric CO 2 on soil nematodes was only observed under favorable conditions. The response of nematode communities to elevated atmospheric CO 2 may indicate the change of soil food web.
基金National Natural Science Foundation of China （nos. 40231003 , 40110817） Knowledge Innovation Program of Chinese Academy of Sciences （no. KZCX2-408） the National Key Project on Basic Sciences （no. 2002CB714003）.
文摘A hydroponics experiment was conducted to investigate the rice root growth in FACE （free-air carbon dioxide enrichment）. The root biomass, root volume, ratio of root/shoot, number of adventitious roots and root diameter significantly increased under FACE conditions, while the CO2 enrichment decreased the N concentration in rice roots without any change in the C content, leading to an increase in root C：N ratio. Moreover, the elevated CO2 resulted in a remarkable decrease of root activity, expressed as per unit root dry weight, which might be responsible for decreased N concentration in roots.
文摘Mammography x-rays standard is required to improve the quality of mammary machine and reduce the dose for w omen and staff. The molybdenum target x-rays machine is used as the radiation source and free-air cylindrical chamber is designed for detecting photon. Four standard radiation qualities are established w ith international standard documents as references. The Correction factors including air attenuation,scattered radiation,fluorescence,w all transmission,electron loss are studied in the four radiation quality. The uncertainty in absolute measurement of air-kerma includes air volume measurement of ionization chambers,current measurement,measurement of temperature and pressure,measurement of correction factors,physical constants and orientation of the reference distance. The relative combined standard uncertainty is 0.24%.
基金funded by the National Natural Science Foundation of China(No.30270777)the Key Direction Research of Knowledge Innovation in Chinese Academy of Science(No.KZCX3-SW-440)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Free air CO2 enrichment(FACE) and nitrogen(N) have marked effects on rice root growth,and numerical simulation can explain these effects. To further define the effects of FACE on root growth of rice, an experiment was performed, using the hybrid indica cultivar Xianyou63. The effects of increasing atmospheric CO2 concentration [CO2], 200 μmol mol-1higher than ambient, on the growth of rice adventitious roots were evaluated, with two levels of N: low(LN, 125 kg ha-1) and normal(NN, 250 kg ha-1). The results showed a significant increase in both adventitious root number(ARN) and adventitious root length(ARL) under FACE treatment. The application of nitrogen also increased ARN and ARL, but these increases were smaller than that under FACE treatment. On the basis of the FACE experiment, numerical models for rice adventitious root number and length were constructed with time as the driving factor. The models illustrated the dynamic development of rice adventitious root number and length after transplanting, regulated either by atmospheric [CO2] or by N application.The simulation result was supported by statistical tests comparing experimental data from different years, and the model yields realistic predictions of root growth. These results suggest that the models have strong predictive potential under conditions of atmospheric [CO2] rises in the future.
基金supported by the National Natural Science Foundation of China(No.30770400,40231003)the Knowledge Innovation Program of Chinese Academy of Sciences(No.KZCX2-408)
文摘Elevated atmospheric CO2 can influence soil C dynamics in agroecosystems. The effects of free-air CO2 enrichment （FACE） and N fertilization on soil organic C （Corg）, dissolved organic C （DOC）, microbial biomass C （Cmic） and soil basal respiration （SBR） were investigated in a Chinese wheat field after expose to elevated CO2 for four full years. The results indicated that elevated CO2 has stimulative effects on soil C concentrations regardless of N fertilization. Following the elevated CO2, the concentrations of Corg and SBR were increased at wheat jointing stage, and those of DOC and Cmic were enhanced obviously across the wheat jointing stage and the fallow period after wheat harvest. On the other hand, N fertilization did not significantly affect the content of soil C. Significant correlations were found among DOC, Cmic, and SBR in this study.
基金National Basic Research Program of China(2014CB954500)National Natural Science Foundation of China(31261140364,31370457).
文摘Background:Increasing atmospheric[CO_(2)]can increase photosynthesis and promote plant growth,consequently influencing nitrogen(N)cycling.Yet,there is no systematic information on the N response among different organs of japonica and indica rice genotypes to elevated[CO_(2)]as affected by N application.To investigate the impacts of elevated[CO_(2)]and N fertilization on N uptake and utilization of different genotypic rice(Oryza sativa L.)during grain filling,a free-air CO_(2) enrichment(FACE)experiment with indica cv.Liangyou 084(IIY084)and japonica cv.Wuyunjing 23(WYJ23)was conducted in Eastern China.Crops were exposed to ambient[CO_(2)]and elevated[CO_(2)](200μmol mol^(−1) above ambient)at two levels of N:control(0N)and 22.5 g N m^(−2)(normal N,NN),and they were sampled at 82 days after transplanting(DAT),99 DAT,and maturity,respectively.Results:Under FACE,significant declines of N concentration in all tissues and the whole plants were observed with the greater decrease in leaves and stems at three stages.Positive responses of N use efficiency(NUE)to elevated[CO_(2)]were recorded over the study period.The total N accumulation remained unchanged,while a large amount of N was partitioned to panicles at the expense of leaves and stems.As compared to WYJ23,greater N transportation from roots to aboveground,especially the panicles,was observed on IIY084 accompanied by higher panicle biomass(82 DAT and 99 DAT),N concentrations(maturity),and greater NUE for leaves through the study season.Across all[CO_(2)]and cultivars,N fertilization increased N partitioning to leaves and stems while decreasing that to panicles.Additionally,N supply decreased NUE while stimulating N concentrations and N amounts of rice plants.Among all treatments,IIY084 had the highest N accumulation and allocation in panicles under elevated[CO_(2)]in combination with N fertilizer at maturity.Conclusion:Data from this study were helpful for understanding the temporal N uptake and utilization of different rice genotypes as affected by N availability and suggest that IIY084 promises a considerable prospect for its grain yield and quality under future elevated atmospheric[CO_(2)].
文摘A free-air ionization chamber in low-energy X-ray has been designed and manufactured at the National Institute of Metrology （NIM, China） according to the defination of air-kerma. The results of a preliminary test show that the leakage current of ionization chamber is around 2×10^-15A, and the correction factor of ion recombination for the ionization chamber is also obtained. The free-air ionization chamber is suitable for the primary standard in low-energy X-rays.
基金the Key Project of the National Natural Science Foundation of China (Grant No. 40110817)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX3-SW-440)+1 种基金China Postdoctoral Science FoundationJiangsu Planned Projects for Postdoctoral Research Funds
文摘The responses of rice to the second degree contamination of copper were studied by pot experiments under free-air CO2 enrichment (FACE) with 570 μmol·mol-1 of CO2. The results showed that the content of copper in rice leaves was reduced with the CO2 concentration reaching 570 μmol·mol-1 and this happened more significantly under the second degree contamination of copper. Under FACE, activities of superoxide dismutase (SOD) enzyme in rice leaves treated by copper contamination were induced, whereas the contents of glutathione (GSH) and glutathione disulfide (GSSG) had no significant difference from the control. In the presence of ambient CO2, activities of SOD enzyme treated by copper pollution were suppressed during the whole rice growth, however, the contents of GSH and GSSG were induced at tillering and jointing stages, and then restored to the control levels in later growth under the second degree contamination of copper. With the rice growing, the content of malondialdehyde (MDA) rises continuously, but there had been no significant difference between the treatments at the same growth stage. Further studies are needed on the response mechanism of rice to Cu stress under elevated CO2.
基金supported by KeyArea Research and Development Program of Guangdong ProvinceChina(2020B020201006)to Chunwu Zhu+5 种基金National Natural Science Foundation of China(31870423)to Chunwu ZhuNational Natural Science Foundation of China(41930758)to Fang-Jie ZhaoJiangsu Science and Technology Department(BM20222002)to Chunwu ZhuCarbon Peaking and Carbon Neutrality Special Fund for Science and Technology from Nanjing Science and Technology Bureau(20221103)to Chunwu ZhuKey Research and Development Program of Jiangsu Province(BE2022308)to Chunwu ZhuErdos City Science and Technology Major Project(2022EEDSKJZDZX010)to Chunwu Zhu。
文摘Elevated atmospheric carbon dioxide concentration([CO_(2)])can stimulate crop growth and increase yield,but the effect may be constrained by soil contamination with heavy metals.In a free-air carbon dioxide enrichment experiment over three seasons,we found that soil heavy metal contamination can constrain or even reverse the projected CO_(2)fertilization effect on rice yield.Elevated[CO_(2)]produced opposing effects on the accumulation of arsenic and cadmium in rice grain.Breeding crops for heavy-metal resistance and low arsenic accumulation may become necessary with continuing climate change.
文摘人类活动导致的大气和气候变化将极大地改变作物的生长环境,其中最大的一个变化就是大气二氧化碳(CO2)浓度的迅速上升:从工业革命前的平均270μmol/mol上升到目前的381μmol/mol,到2050年至少超过550μmol/mol。FACE(Free-air CO2 enrichment,开放式空气中CO2浓度增高)试验是目前评估未来高浓度CO2对作物生长和产量实际影响的最佳方法。水稻无疑是人类最重要的食物来源,迄今为止人类利用FACE技术开展水稻响应和适应的研究已有10a(19982008年)的历史。以生长发育为主线,首次系统综述了10a水稻FACE试验在该领域的研究成果,总结了FACE情形下高浓度CO2(模拟本世纪中叶大气CO2浓度)对主要供试水稻品种(小区面积大于4m2)光合作用、生育进程、地上部生长、地下部生长、物质分配、籽粒灌浆、产量构成以及倒伏性状等影响的研究进展,比较了FACE与非FACE研究之间以及中国和日本FACE研究(世界上唯一的两个大型水稻FACE研究)之间的异同点。根据研究进展以及当前的技术水平,文章最后提出了该领域的3个优先课题:(1)FACE情形下杂交稻生产力响应高于预期的生物学机制;(2)FACE情形下CO2与主要栽培措施的互作效应;(3)FACE情形下CO2与主要空气污染物臭氧的互作效应。这些响应的机理性解析将有助于从根本上减少人类预测未来粮食安全的不确定性,进而更加有效地制订出应对全球变化的适应策略。
