The effects of cyclic loading on crack growth, fracture feature and rupture life of superalloy GH2132 have been studied in the present paper. The crack growth tests were carried out at 550 on compact tension specimens...The effects of cyclic loading on crack growth, fracture feature and rupture life of superalloy GH2132 have been studied in the present paper. The crack growth tests were carried out at 550 on compact tension specimens under a wide range of load levels and various periods of hold time, and the fracture surfaces were examined on a scanning electron microscope. The results show that, for both static and cyclic creep, Stage-I of crack growth is related with initial test stress, during which the crack extension is about 0.5mm, and that the final effect of cyclic loading on rupture life depends on the counteraction of its two reversed effects on crack growth rate before and after the point n=0.2.展开更多
协同实现水稻高产和碳减排对维护国家粮食自给和实现碳达峰碳中和意义重大。为定量分析华南地区水稻生产碳足迹及构成特征,明确栽培技术对水稻产量及碳足迹的影响,本研究在广东省4个典型的水稻产区开展田间试验,利用生命周期评价法分析...协同实现水稻高产和碳减排对维护国家粮食自给和实现碳达峰碳中和意义重大。为定量分析华南地区水稻生产碳足迹及构成特征,明确栽培技术对水稻产量及碳足迹的影响,本研究在广东省4个典型的水稻产区开展田间试验,利用生命周期评价法分析不同栽培技术模式的水稻产量、肥料利用率和间接碳足迹及其构成。结果表明,广东省籼稻生产单位面积碳足迹为1235.3~1487.7 kg CO_(2)-eq/hm^(2),单位产量碳足迹为0.12~0.31 kg CO_(2)-eq/kg;栽培技术对水稻产量、化肥利用效率、灌溉次数和单位产量碳足迹有显著影响。与常规栽培技术相比,低碳高产栽培技术显著减少氮肥用量,并提高了水稻产量,栽培技术和品种之间无显著交互作用。相同技术模式下,单位产量间接碳足迹与产量呈极显著负相关,表明在相同种植条件下选用高产水稻品种能有效降低单位产量碳足迹。示范区的多点试验表明,与常规栽培技术相比,低碳高产栽培技术水稻产量增加3.67%~21.62%,氮肥偏生产力提高21.68%~60.81%,每季平均减少灌溉次数4次,单位面积碳足迹和单位产量碳足迹均值分别减少6.11%和16.19%。柴油和氮肥是影响间接碳足迹的关键因子,两者碳排放分别占总间接排放量49.65%~52.88%和30.62%~34.70%。平均每减少1 kg氮肥,碳足迹降低2.49 kg CO_(2)-eq/hm^(2)。水稻单位产量间接碳足迹与氮肥偏生产力呈极显著负相关,表明提高单位产量和氮肥利用率能有效减少水稻单产间接碳足迹。综上表明,华南地区水稻生产可通过选用高产水稻品种,结合水肥优化栽培技术降低氮肥和灌溉水投入,提高水稻产量和氮肥利用率,减少单位面积碳足迹和单位产量碳足迹,实现高产与低碳排的协同。展开更多
文摘The effects of cyclic loading on crack growth, fracture feature and rupture life of superalloy GH2132 have been studied in the present paper. The crack growth tests were carried out at 550 on compact tension specimens under a wide range of load levels and various periods of hold time, and the fracture surfaces were examined on a scanning electron microscope. The results show that, for both static and cyclic creep, Stage-I of crack growth is related with initial test stress, during which the crack extension is about 0.5mm, and that the final effect of cyclic loading on rupture life depends on the counteraction of its two reversed effects on crack growth rate before and after the point n=0.2.
文摘协同实现水稻高产和碳减排对维护国家粮食自给和实现碳达峰碳中和意义重大。为定量分析华南地区水稻生产碳足迹及构成特征,明确栽培技术对水稻产量及碳足迹的影响,本研究在广东省4个典型的水稻产区开展田间试验,利用生命周期评价法分析不同栽培技术模式的水稻产量、肥料利用率和间接碳足迹及其构成。结果表明,广东省籼稻生产单位面积碳足迹为1235.3~1487.7 kg CO_(2)-eq/hm^(2),单位产量碳足迹为0.12~0.31 kg CO_(2)-eq/kg;栽培技术对水稻产量、化肥利用效率、灌溉次数和单位产量碳足迹有显著影响。与常规栽培技术相比,低碳高产栽培技术显著减少氮肥用量,并提高了水稻产量,栽培技术和品种之间无显著交互作用。相同技术模式下,单位产量间接碳足迹与产量呈极显著负相关,表明在相同种植条件下选用高产水稻品种能有效降低单位产量碳足迹。示范区的多点试验表明,与常规栽培技术相比,低碳高产栽培技术水稻产量增加3.67%~21.62%,氮肥偏生产力提高21.68%~60.81%,每季平均减少灌溉次数4次,单位面积碳足迹和单位产量碳足迹均值分别减少6.11%和16.19%。柴油和氮肥是影响间接碳足迹的关键因子,两者碳排放分别占总间接排放量49.65%~52.88%和30.62%~34.70%。平均每减少1 kg氮肥,碳足迹降低2.49 kg CO_(2)-eq/hm^(2)。水稻单位产量间接碳足迹与氮肥偏生产力呈极显著负相关,表明提高单位产量和氮肥利用率能有效减少水稻单产间接碳足迹。综上表明,华南地区水稻生产可通过选用高产水稻品种,结合水肥优化栽培技术降低氮肥和灌溉水投入,提高水稻产量和氮肥利用率,减少单位面积碳足迹和单位产量碳足迹,实现高产与低碳排的协同。
