With the development of technology for earthquake resistant,the research of the low yield point(LYP) steel which used for the fabrication of energy dissipation damper were paid more and more attention.The common studi...With the development of technology for earthquake resistant,the research of the low yield point(LYP) steel which used for the fabrication of energy dissipation damper were paid more and more attention.The common studies of the low yield point steel is mainly about the performance with constant amplitude and constant frequency.The low cycle fatigue properties of low yield piont steel were studied by series of test with continuous varying amplitude and varying frequency with the materials testing system by us.The test results showed that low yield point steel of Baosteel have excellent low cycle fatigue properties,which meet the requirement for steel used for the fabrication of energy dissipation damper completely.The low cycle fatigue performance of low yield point steel of Baosteel mainly depended on the amplitude in test.And the effect of varying frequency for the low yield point steel was more less than varying amplitude.展开更多
Mechanical properties of Mg-3Gd(wt.%)samples with average grain sizes ranging from 3 to 45μm were characterized by room temperature tensile test.A reversal of the trade-off,i.e.,high yield strength and large tensile ...Mechanical properties of Mg-3Gd(wt.%)samples with average grain sizes ranging from 3 to 45μm were characterized by room temperature tensile test.A reversal of the trade-off,i.e.,high yield strength and large tensile elongation,was simultaneously observed in the fine-grained samples.The microstructures and hardening response were analyzed in terms of the viewpoint of strain evolution,including local strain evolution by tensile digital image correlation strain measurement,and lattice strain by using synchrotronbased in-situ high energy X-ray diffraction technique.The dislocation-based deformation mechanisms were investigated to underpin the microstructural origin of the yield point phenomenon and enhancement in work-hardening.The occurrence of the yield point phenomenon represented by a yield drop and propagation of the Lüders band is related to the absence of mobile dislocations at an early stage and to the slip transmission between the adjacent grain.The extraordinary work-hardening enhancement over an extended range can be ascribed mainly to the increases in dislocation multiplication and accumulation capabilities by the activation and interaction of multiple slip systems including<a>and<c+a>types.These results contribute to the design of strong and ductile Mg alloys.展开更多
The optimized nitrogen fertilization location differs in different rice-growing regions. We optimized nitrogen deep-point application in root-growing zone（NARZ） for transplanted rice in subtropical China. Field plot...The optimized nitrogen fertilization location differs in different rice-growing regions. We optimized nitrogen deep-point application in root-growing zone（NARZ） for transplanted rice in subtropical China. Field plot experiments were conducted over two years（2014–2015） in a double-rice cropping system to evaluate the effects of nitrogen（N） fertilizer location on grain yield and N use efficiency（NUE）. Four different nitrogen deep-point application methods（DN） were compared with traditional broadcast application（BN） using granular urea. The results showed that grain yield, recovery efficiency of N（REN）, agronomic efficiency of N（AEN）, and partial factor productivity of N（PFP_N） significantly increased 10.3–63.4, 13.7–56.7, 24.7–201.9 and 10.2–63.4%, respectively, in DN treatment compared to BN, respectively. We also find that DN treatments increased grain yield as well as grain N content, and thus grain quality, in comparison with conventional BN treatment. Correlation analysis indicated that significant improvement in grain yield and NUE mainly resulted from increases in productive panicle number and grain N content. In our proposed NARZ method, granular urea should be placed 0 to 5 cm around the rice seeding at a 12-cm depth druing rice transplanting. In NARZ, balanced application of N, P and K further improved grain yield and NUE over treatments with a single N deep-point application. High N uptake by the rice plant did not cause significant soil fertility depletion, demonstrating that this method could guarantee sustainable rice production.展开更多
Traditional studies on potential yield mainly referred to attainable yield： the maximum yield which could be reached by a crop in a given environment. The new concept of crop yield under average climate conditions wa...Traditional studies on potential yield mainly referred to attainable yield： the maximum yield which could be reached by a crop in a given environment. The new concept of crop yield under average climate conditions was defined in this paper, which was affected by advancement of science and technology. Based on the new concept of crop yield, the time series techniques relying on past yield data was employed to set up a forecasting model. The model was tested by using average grain yields of Liaoning Province in China from 1949 to 2005. The testing combined dynamic n-choosing and micro tendency rectification, and an average forecasting error was 1.24%. In the trend line of yield change, and then a yield turning point might occur, in which case the inflexion model was used to solve the problem of yield turn point.展开更多
Sediment has been identified as a significant threat to water quality and channel clogging that in turn may lead to river flooding. With the increasing awareness of the impairment from sediment to water bodies in a wa...Sediment has been identified as a significant threat to water quality and channel clogging that in turn may lead to river flooding. With the increasing awareness of the impairment from sediment to water bodies in a watershed, identifying the locations of the major sediment sources and reducing the sediment through management practices will be important for an effective watershed management. The annualized agricultural non-point source pollution(AnnAGNPS) model and newly developed GIS interface for it were applied in a small agricultural watershed, Redrock Creek watershed, Kansas, in this pilot study for exploring the effectiveness of using this model as a management tool. The calibrated model appropriately simulated monthly runoff and sediment yield through the practices in this study and potentially suggested the ways of sediment reduction through evaluating the changes of land use and field operation in the model for the purpose of watershed management.展开更多
文摘With the development of technology for earthquake resistant,the research of the low yield point(LYP) steel which used for the fabrication of energy dissipation damper were paid more and more attention.The common studies of the low yield point steel is mainly about the performance with constant amplitude and constant frequency.The low cycle fatigue properties of low yield piont steel were studied by series of test with continuous varying amplitude and varying frequency with the materials testing system by us.The test results showed that low yield point steel of Baosteel have excellent low cycle fatigue properties,which meet the requirement for steel used for the fabrication of energy dissipation damper completely.The low cycle fatigue performance of low yield point steel of Baosteel mainly depended on the amplitude in test.And the effect of varying frequency for the low yield point steel was more less than varying amplitude.
基金financially supported by the National Key Research and Develop-ment Program(No.2023YFB3712702)the National Natural Science Foundation of China(Nos.52071038,52071039,and 52301156)the Natural Science Foundation of Jiangsu Province(Nos.BK20232025 and BK20243005)。
文摘Mechanical properties of Mg-3Gd(wt.%)samples with average grain sizes ranging from 3 to 45μm were characterized by room temperature tensile test.A reversal of the trade-off,i.e.,high yield strength and large tensile elongation,was simultaneously observed in the fine-grained samples.The microstructures and hardening response were analyzed in terms of the viewpoint of strain evolution,including local strain evolution by tensile digital image correlation strain measurement,and lattice strain by using synchrotronbased in-situ high energy X-ray diffraction technique.The dislocation-based deformation mechanisms were investigated to underpin the microstructural origin of the yield point phenomenon and enhancement in work-hardening.The occurrence of the yield point phenomenon represented by a yield drop and propagation of the Lüders band is related to the absence of mobile dislocations at an early stage and to the slip transmission between the adjacent grain.The extraordinary work-hardening enhancement over an extended range can be ascribed mainly to the increases in dislocation multiplication and accumulation capabilities by the activation and interaction of multiple slip systems including<a>and<c+a>types.These results contribute to the design of strong and ductile Mg alloys.
基金financially supported by the National Basic Research Program of China(2013CB127401)the National Natural Science Foundation of China(41401258)+1 种基金the Natural Science Foundation of Jiangsu Province,China(BK20131044)the Natural Science Foundation of Jiangxi Province,China(20142BAB214005)
文摘The optimized nitrogen fertilization location differs in different rice-growing regions. We optimized nitrogen deep-point application in root-growing zone（NARZ） for transplanted rice in subtropical China. Field plot experiments were conducted over two years（2014–2015） in a double-rice cropping system to evaluate the effects of nitrogen（N） fertilizer location on grain yield and N use efficiency（NUE）. Four different nitrogen deep-point application methods（DN） were compared with traditional broadcast application（BN） using granular urea. The results showed that grain yield, recovery efficiency of N（REN）, agronomic efficiency of N（AEN）, and partial factor productivity of N（PFP_N） significantly increased 10.3–63.4, 13.7–56.7, 24.7–201.9 and 10.2–63.4%, respectively, in DN treatment compared to BN, respectively. We also find that DN treatments increased grain yield as well as grain N content, and thus grain quality, in comparison with conventional BN treatment. Correlation analysis indicated that significant improvement in grain yield and NUE mainly resulted from increases in productive panicle number and grain N content. In our proposed NARZ method, granular urea should be placed 0 to 5 cm around the rice seeding at a 12-cm depth druing rice transplanting. In NARZ, balanced application of N, P and K further improved grain yield and NUE over treatments with a single N deep-point application. High N uptake by the rice plant did not cause significant soil fertility depletion, demonstrating that this method could guarantee sustainable rice production.
基金Supported by Agricultural Poor-helping Monopoly of Graduate University of Chinese Academy of Science (40641002)
文摘Traditional studies on potential yield mainly referred to attainable yield： the maximum yield which could be reached by a crop in a given environment. The new concept of crop yield under average climate conditions was defined in this paper, which was affected by advancement of science and technology. Based on the new concept of crop yield, the time series techniques relying on past yield data was employed to set up a forecasting model. The model was tested by using average grain yields of Liaoning Province in China from 1949 to 2005. The testing combined dynamic n-choosing and micro tendency rectification, and an average forecasting error was 1.24%. In the trend line of yield change, and then a yield turning point might occur, in which case the inflexion model was used to solve the problem of yield turn point.
文摘Sediment has been identified as a significant threat to water quality and channel clogging that in turn may lead to river flooding. With the increasing awareness of the impairment from sediment to water bodies in a watershed, identifying the locations of the major sediment sources and reducing the sediment through management practices will be important for an effective watershed management. The annualized agricultural non-point source pollution(AnnAGNPS) model and newly developed GIS interface for it were applied in a small agricultural watershed, Redrock Creek watershed, Kansas, in this pilot study for exploring the effectiveness of using this model as a management tool. The calibrated model appropriately simulated monthly runoff and sediment yield through the practices in this study and potentially suggested the ways of sediment reduction through evaluating the changes of land use and field operation in the model for the purpose of watershed management.
