通过ProCAST软件模拟了定向凝固温度场分布,优化了定向凝固工艺,制备了φ13 mm Cu-15Ni-8Sn合金棒材。首先对合金进行固溶处理,随后进行冷拉拔变形及时效处理。采用光学显微镜、透射电镜、显微硬度仪和力学试验机等研究了合金经不同工...通过ProCAST软件模拟了定向凝固温度场分布,优化了定向凝固工艺,制备了φ13 mm Cu-15Ni-8Sn合金棒材。首先对合金进行固溶处理,随后进行冷拉拔变形及时效处理。采用光学显微镜、透射电镜、显微硬度仪和力学试验机等研究了合金经不同工艺处理后的组织和性能。结果表明:固溶态棒材经65%冷拉拔变形后,硬度从121 HV上升到了285 HV,平均晶粒尺寸由15.7μm下降到0.94μm。变形态合金组织呈纤维状,形成较强的<111>//X_(0)方向的丝织构;变形态合金线材在380℃时效过程中,先发生调幅分解,然后析出DO_(22)有序相,60 min时合金硬度达到峰值399 HV,抗拉强度为1446 MPa;时效时间继续延长,进入过时效态,开始析出长条状不连续析出相(DO_(3)相),其长大形成层片状结构,导致合金性能急剧下降。展开更多
Efficient N fertilizer management is critical for the economic production of rice and the long-term protection of environmental quality. A field experiment was designed to study the effects of N fertilizer management ...Efficient N fertilizer management is critical for the economic production of rice and the long-term protection of environmental quality. A field experiment was designed to study the effects of N fertilizer management practices on grain yield and N uptake office. The experiment was laid out in the randomized complete block design with four replications in Central China during 2008 and 2009. Five N treatments denoted as No, NIsoA, N15oB, N24OA, and N24oB, respectively, were studied. NO represented no N application and served as a control, N15OA and N15oB indicated the total N application of 150 kg N ha-I but with two different application schedules （A and B） across the early stage of rice growth. Schedule A was applied as follows： 40% basal, 30% at 10 d after transplanting （DAT） and 30% at 36 DAT （nearly at the panicle initiation stage）, while schedule B was as follows： 30% at basal, 20% at 10 DAT, and 50% at 36 DAT. Similarly, N240A and N240B indicated the total N application of 240 kg N ha-1 with schedules A and B as described above. To quantify N uptake from fertilizer and soil, a 15N experiment was also conducted within the main experimental field, with micro-plots. Grain yields were significantly increased as N rates increased from 0 to 240 kg N ha-1. At the same rate, splitting N application as schedule B significantly increased the grain yield, spikelets per panicle, percentage of ripened grain, and 1 000-grain weight, compared with the N application according to schedule A. Mean rice recovery of N fertilizer by ~SN tracing method ranged from 25.39% at N24oA to 34.89% at NIsoB, however, N fertilizer residual rate in the soil ranged from 12.40% at N240A to 16.61% at N^s0w About 31.5 and 28.5% of total uptake of ~SN derived from basal fertilizer was absorbed at panicle initiation and heading stages, respectively. However, 65.6-92.5% of total uptake of 15N derived from topdressing fertilizer was absorbed at the heading stage. Based on yield and nitrogen recovery efficiency, splitting N application according to schedule B at the rate of 240 kg N ha-1 will be more profitable among the tested five N treatments in Central China.展开更多
基金supported by the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2011BAD16B02)the Natural Science Foundation of Guangdong Province, China(S2011040004466)
文摘Efficient N fertilizer management is critical for the economic production of rice and the long-term protection of environmental quality. A field experiment was designed to study the effects of N fertilizer management practices on grain yield and N uptake office. The experiment was laid out in the randomized complete block design with four replications in Central China during 2008 and 2009. Five N treatments denoted as No, NIsoA, N15oB, N24OA, and N24oB, respectively, were studied. NO represented no N application and served as a control, N15OA and N15oB indicated the total N application of 150 kg N ha-I but with two different application schedules （A and B） across the early stage of rice growth. Schedule A was applied as follows： 40% basal, 30% at 10 d after transplanting （DAT） and 30% at 36 DAT （nearly at the panicle initiation stage）, while schedule B was as follows： 30% at basal, 20% at 10 DAT, and 50% at 36 DAT. Similarly, N240A and N240B indicated the total N application of 240 kg N ha-1 with schedules A and B as described above. To quantify N uptake from fertilizer and soil, a 15N experiment was also conducted within the main experimental field, with micro-plots. Grain yields were significantly increased as N rates increased from 0 to 240 kg N ha-1. At the same rate, splitting N application as schedule B significantly increased the grain yield, spikelets per panicle, percentage of ripened grain, and 1 000-grain weight, compared with the N application according to schedule A. Mean rice recovery of N fertilizer by ~SN tracing method ranged from 25.39% at N24oA to 34.89% at NIsoB, however, N fertilizer residual rate in the soil ranged from 12.40% at N240A to 16.61% at N^s0w About 31.5 and 28.5% of total uptake of ~SN derived from basal fertilizer was absorbed at panicle initiation and heading stages, respectively. However, 65.6-92.5% of total uptake of 15N derived from topdressing fertilizer was absorbed at the heading stage. Based on yield and nitrogen recovery efficiency, splitting N application according to schedule B at the rate of 240 kg N ha-1 will be more profitable among the tested five N treatments in Central China.
