High energy γ-rays can be used in many fields, such as nuclear waste transmutation, flash photographics, and astrophysics. The13 C(p, γ)14 N resonance reaction was used to generate high energy and mono-energetic γ-...High energy γ-rays can be used in many fields, such as nuclear waste transmutation, flash photographics, and astrophysics. The13 C(p, γ)14 N resonance reaction was used to generate high energy and mono-energetic γ-rays in this work. The thick-target yield of the 9.17-MeV γ-ray from the resonance in this reaction was determined to be(4.7±0.4)×10-9γ/proton,which was measured by a HPGe detector. Meanwhile, the angular distribution of 9.17-MeV γ-ray was also determined.The absolute efficiency of HPGe detector was calibrated using56 Co and152 Eu sources with known radioactive activities and calculated by GEANT4 simulation.展开更多
Soil test crop response (STCR) correlation studies were carried out in Vindhyan alluvial plain during 2001 to 2004 taking IR-36 as test crop to quantify rice production in the context of the variability of soil proper...Soil test crop response (STCR) correlation studies were carried out in Vindhyan alluvial plain during 2001 to 2004 taking IR-36 as test crop to quantify rice production in the context of the variability of soil properties and use of balanced fertilizers based on targeted yield concept. The soils were developed on gently sloping alluvial plain with different physiographic settings and notable variation in drainage condition. Soil properties show moderate variation in texture (loamy to clay), organic carbon content (4.4 to 9.8 g/kg), cation exchange capacity (10.2 to 22.4 cmol (p+)/kg) and pH (5.3 to 6.4). Soil fertility status for N is low to medium (224 to 348 kg/ha), P is medium to high (87 to 320 kg/ha) and K ranges from medium to high (158 to 678 kg/ha). Database regarding nutrient requirement in kg/t of grain produce (NR), the percent contribution from the soil available nutrients [CS (%)] and the percent contribution from the applied fertilizer nutrients [CF (%)] were computed for calibrating and formulating fertilizer recommendations. Validity of the yield target for 7 and 8 t/ha was tested in farmers’ fields and yields targets varied at less than 10%. The percent achievement of targets aimed at different level was more than 90%, indicating soil test based fertilizer recommendation approach was economically viable within the agro-ecological zone with relatively uniform cropping practices and socio-economic conditions.展开更多
Measurement of the neutron yield is performed at a primary energy of 400 MeV/u carbons for the Pb target.Water-bath activation-foil method is used in a moderation measurement with Au foils to detect the moderated neut...Measurement of the neutron yield is performed at a primary energy of 400 MeV/u carbons for the Pb target.Water-bath activation-foil method is used in a moderation measurement with Au foils to detect the moderated neutrons. The neutron yield is determined to be 18.4±2.1 per carbon by integrating the neutron flux over the entire water volume. The corresponding simulation values are performed by Geant4 code with three models to compare with the experimental results. The comparison shows that the calculated result with the INCL model is in good agreement with the experimental data.展开更多
Neutron energy, fluence rate, angular distributions and dose equivalent rate distributions around the thick Be, Cu, An targets bombarded by 50 MeV/u 18O-ion were measured using a threshold detector activation method. ...Neutron energy, fluence rate, angular distributions and dose equivalent rate distributions around the thick Be, Cu, An targets bombarded by 50 MeV/u 18O-ion were measured using a threshold detector activation method. At the same time,the neutron yields of 18O-ion and the neutron emission rates in the forward direction were obtained approximately.展开更多
China＇s Super Hybrid Rice Breeding Program has made significant progress over the past two decades. In this paper, we reviewed our studies on the yield potential and stability in super hybrid rice and discussed the s...China＇s Super Hybrid Rice Breeding Program has made significant progress over the past two decades. In this paper, we reviewed our studies on the yield potential and stability in super hybrid rice and discussed the strategies for super hybrid rice production. The results of our studies show that rice yield potential has been increased by 12% in super hybrid cultivars as compared with ordinary hybrid and inbred cultivars. The higher grain yields in super hybrid rice cultivars are attributed to larger panicle size coupled with higher biomass production or higher harvest index. However, grain yields in super hybrid rice cultivars vary widely among locations depending on soil and climatic factors. Therefore, it is important to tailor target yield to local conditions in super hybrid rice production. The target yield for super hybrid rice production can be determined by the average yield method or the regression model method. Improving soil quality is critical to achieving the target yield in super hybrid rice production. Favorable crop rotations such as rice-oilseed rape and novel soil management practices, such as biochar addition, are effective approaches to improve soil quality. It is needed to develop simplified cultivation tech- nologies for super hybrid rice to meet the changes in socioeconomic environments during the period of transition. There are such technologies as no-tillage direct seeding and mechanized transplanting at high hill density with single seedling per hill.展开更多
Low density and low convergence implosion occurs in the exploding-pusher target experiment, and generates neutrons isotropically to develop a high yield platform.In order to validate the performance of ShenGuang(SG) l...Low density and low convergence implosion occurs in the exploding-pusher target experiment, and generates neutrons isotropically to develop a high yield platform.In order to validate the performance of ShenGuang(SG) laser facility and test nuclear diagnostics, all 48-beam lasers with an on-target energy of 48 kJ were firstly used to drive room-temperature, DT gas-filled glass targets.The optimization has been carried out and optimal drive uniformity was obtained by the combination of beam repointing and target.The final irradiation uniformity of less than 5% on polar direct-drive capsules of 540 μm in diameter was achieved, and the highest thermonuclear yield of the polar direct-drive DT fuel implosion at the SG was 1.04 × 10^(13).The experiment results show neutron yields severely depend on the irradiation uniformity and laser timing,and decrease with the increase of the diameter and fuel pressure of the target.The thin CH ablator does not impact the implosion performance, but the laser drive uniformity is important.The simulated results validate that the cos γ distribution laser design is reasonable and can achieve a symmetric pressure distribution.Further optimization will focus on measuring the symmetry of the hot spot by self-emission imaging, increasing the diameter, and decreasing the fuel pressure.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11655003)
文摘High energy γ-rays can be used in many fields, such as nuclear waste transmutation, flash photographics, and astrophysics. The13 C(p, γ)14 N resonance reaction was used to generate high energy and mono-energetic γ-rays in this work. The thick-target yield of the 9.17-MeV γ-ray from the resonance in this reaction was determined to be(4.7±0.4)×10-9γ/proton,which was measured by a HPGe detector. Meanwhile, the angular distribution of 9.17-MeV γ-ray was also determined.The absolute efficiency of HPGe detector was calibrated using56 Co and152 Eu sources with known radioactive activities and calculated by GEANT4 simulation.
基金Project supported by the Indian Council of Agricultural Research, and the National Agricultural Technology Program, India
文摘Soil test crop response (STCR) correlation studies were carried out in Vindhyan alluvial plain during 2001 to 2004 taking IR-36 as test crop to quantify rice production in the context of the variability of soil properties and use of balanced fertilizers based on targeted yield concept. The soils were developed on gently sloping alluvial plain with different physiographic settings and notable variation in drainage condition. Soil properties show moderate variation in texture (loamy to clay), organic carbon content (4.4 to 9.8 g/kg), cation exchange capacity (10.2 to 22.4 cmol (p+)/kg) and pH (5.3 to 6.4). Soil fertility status for N is low to medium (224 to 348 kg/ha), P is medium to high (87 to 320 kg/ha) and K ranges from medium to high (158 to 678 kg/ha). Database regarding nutrient requirement in kg/t of grain produce (NR), the percent contribution from the soil available nutrients [CS (%)] and the percent contribution from the applied fertilizer nutrients [CF (%)] were computed for calibrating and formulating fertilizer recommendations. Validity of the yield target for 7 and 8 t/ha was tested in farmers’ fields and yields targets varied at less than 10%. The percent achievement of targets aimed at different level was more than 90%, indicating soil test based fertilizer recommendation approach was economically viable within the agro-ecological zone with relatively uniform cropping practices and socio-economic conditions.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11575267,11775284,11575289 and 11605258
文摘Measurement of the neutron yield is performed at a primary energy of 400 MeV/u carbons for the Pb target.Water-bath activation-foil method is used in a moderation measurement with Au foils to detect the moderated neutrons. The neutron yield is determined to be 18.4±2.1 per carbon by integrating the neutron flux over the entire water volume. The corresponding simulation values are performed by Geant4 code with three models to compare with the experimental results. The comparison shows that the calculated result with the INCL model is in good agreement with the experimental data.
文摘Neutron energy, fluence rate, angular distributions and dose equivalent rate distributions around the thick Be, Cu, An targets bombarded by 50 MeV/u 18O-ion were measured using a threshold detector activation method. At the same time,the neutron yields of 18O-ion and the neutron emission rates in the forward direction were obtained approximately.
基金supported by the Earmarked Fund for China Agriculture Research System(CARS-01)
文摘China＇s Super Hybrid Rice Breeding Program has made significant progress over the past two decades. In this paper, we reviewed our studies on the yield potential and stability in super hybrid rice and discussed the strategies for super hybrid rice production. The results of our studies show that rice yield potential has been increased by 12% in super hybrid cultivars as compared with ordinary hybrid and inbred cultivars. The higher grain yields in super hybrid rice cultivars are attributed to larger panicle size coupled with higher biomass production or higher harvest index. However, grain yields in super hybrid rice cultivars vary widely among locations depending on soil and climatic factors. Therefore, it is important to tailor target yield to local conditions in super hybrid rice production. The target yield for super hybrid rice production can be determined by the average yield method or the regression model method. Improving soil quality is critical to achieving the target yield in super hybrid rice production. Favorable crop rotations such as rice-oilseed rape and novel soil management practices, such as biochar addition, are effective approaches to improve soil quality. It is needed to develop simplified cultivation tech- nologies for super hybrid rice to meet the changes in socioeconomic environments during the period of transition. There are such technologies as no-tillage direct seeding and mechanized transplanting at high hill density with single seedling per hill.
基金Project supported by the National Natural Science Foundation of China(Grant No.11605178)the Science Challenging Project,China(Grant Nos.JCKY2016212A505 and TZ2016001)
文摘Low density and low convergence implosion occurs in the exploding-pusher target experiment, and generates neutrons isotropically to develop a high yield platform.In order to validate the performance of ShenGuang(SG) laser facility and test nuclear diagnostics, all 48-beam lasers with an on-target energy of 48 kJ were firstly used to drive room-temperature, DT gas-filled glass targets.The optimization has been carried out and optimal drive uniformity was obtained by the combination of beam repointing and target.The final irradiation uniformity of less than 5% on polar direct-drive capsules of 540 μm in diameter was achieved, and the highest thermonuclear yield of the polar direct-drive DT fuel implosion at the SG was 1.04 × 10^(13).The experiment results show neutron yields severely depend on the irradiation uniformity and laser timing,and decrease with the increase of the diameter and fuel pressure of the target.The thin CH ablator does not impact the implosion performance, but the laser drive uniformity is important.The simulated results validate that the cos γ distribution laser design is reasonable and can achieve a symmetric pressure distribution.Further optimization will focus on measuring the symmetry of the hot spot by self-emission imaging, increasing the diameter, and decreasing the fuel pressure.
