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超高强度钢AF1410塑性流动特性及其本构关系 总被引:1,自引:0,他引:1
在本文中,为揭示超高强度钢AF1410的塑性流动性,并研究其塑性流动本构关系,利用CSS4410电子万能试验机和改进的Hopkinson拉压杆技术,对AF1410钢在温度从100K到600K,应变率从0.001/s到2000/s,塑性应变超过20%的塑性流动特性进行了试验研究。结果表明,拉伸加载下AF1410钢屈服强度低于压缩屈服强度,且随应变率增加,拉压屈服强度差值越来越大;该材料塑性流动应力对应变率敏感性低,而对温度较为敏感;随应变率的提高,该材料拉伸失效应变减小,但温度对失效应变无明显影响。最后基于位错的运动学关系,借助试验数据,获得了AF1410钢的塑性流动物理概念本构模型,并通过与经典J-C模型的结果对比对该物理概念本构模型进行了评估分析,表明该物理概念本构模型在较宽温度和应变率范围能较好的预测AF1410钢的塑性流动应力。 相似文献
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氨基酸作为蛋白质的基本组成单位,是重要的生命物质,其单体碳同位素研究在生物地球化学、生态学、生物体代谢和环境科学等领域具有重要意义。该文优化了海参和海藻氨基酸提取和纯化流程,通过N-新戊酰基-O-异丙酯(NPP)方法衍生化后,分别用气相色谱-质谱(GC-MS)和气相色谱-燃烧-同位素比值质谱(GC-C-IRMS)测试其浓度和碳同位素组成。结果显示,15种氨基酸单体的分离效果较好,回收率为46.4%~96.3%,各氨基酸在1.0~16.0μmol/L范围内线性关系良好(r2为0.987~0.999)。15种氨基酸单体衍生物δ13C值的标准偏差均小于0.30‰(n=10),在0.6~2.0 mmol/L浓度范围内δ13C的平均误差为±0.24‰,方法检出限为0.6 nmol。海参和海藻样品各氨基酸单体δ13C值的范围分别为-31.10‰~-8.58‰和-30.53‰~-13.76‰,标准偏差均在0.33‰以内,可满足生物体氨基酸单体碳同位素的测试精度需求。 相似文献
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A low-noise,high-SNR balanced homodyne detector for the bright squeezed state measurement in 1–100 kHz range
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We report a low-noise, high-signal-to-noise-ratio(SNR) balanced homodyne detector based on the standard transimpedance amplifier circuit and the inductance and capacitance combination for the measurement of the bright squeezed state in the range from 1 kHz to 100 kHz. A capacitance is mounted at the input end of the AC branch to prevent the DC photocurrent from entering the AC branch and avoid AC branch saturation. By adding a switch at the DC branch,the DC branch can be flexibly turned on and off on different occasions. When the switch is on, the DC output provides a monitor signal for laser beam alignment. When the switch is off, the electronic noise of the AC branch is greatly reduced at audio-frequency band due to immunity to the impedance of the DC branch, hence the SNR of the AC branch is significantly improved. As a result, the electronic noise of the AC branch is close to -125 dBm, and the maximum SNR of the AC branch is 48 dB with the incident power of 8 mW in the range from 1 kHz to 100 kHz. The developed photodetector paves a path for measuring the bright squeezed state at audio-frequency band. 相似文献
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研究了以Co2+:MgAl2O4晶体为饱和吸收体的LD抽运Er3+,Yb3+共掺磷酸盐玻璃激光器.针对双掺离子之间的能量传递和Er3+的多种跃迁过程,结合Co2+:MgAl2O4晶体中Co2+离子的饱和吸收特性,给出了详尽的速率方程,在其基础上进行了数值分析,分析了输出镜透过率、激光介质长度、谐振腔长度、腔内往返损耗、饱和吸收体长度对激光阈值、峰值功率、单脉冲能量以及脉冲宽度的影响. 相似文献
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