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多阈值采样法是以闪烁脉冲特征模型为先验知识,通过预设多个阈值电压,对脉冲上升沿数字化得到的时间-阈值采样点进行最小均方误差拟合以精确获取脉冲起始时间.高计数率是目前PET仪器发展的一个热点方向,这就要求采用多阈值方法提取时间信息的数据获取系统具有快速高效处理脉冲以减少系统死时间的能力.论文提出了一种基于FPGA的闪烁脉冲上升沿拟合算法,通过数据预处理技术、流水线设计结构和并行处理简化算法复杂度,实现实时闪烁脉冲时间信息快速获取.仿真和实验结果表明,在FPGA上实现该算法的处理速度和精度均达到设计要求,可以满足在高计数率环境下对闪烁脉冲进行实时处理的需求. 相似文献
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A ferroelectric memory diode consisting of Au/PZT/BIT/p-Si multilayer configuration has been fabricated by pulsed laser deposition (PLD) technique. The ferroelectric properties and the memory characteristics are investigated. The P-E curve of the PZT/BIT/p-Si films system had an asymmetry saturated hysteresis loop with P, = 15 μC/cm2 and Ec = 48 kV/cm, and the decay in remanent polarization was only 10% after 109 switching cycles, meanwhile the increase in coercive field was 12% . The C-V hysteresis loop and the I-V curve showed a memory effect derived from the ferroelectric polarization of PZT/BIT films, and the current density was 6.7 × 10-8 A/cm2 at a voltage of + 4V. Our diode had nonvolatile and nondestructive memory readout operation. There was a read current disparity of 0.05 μA for logic "1" and logic "0" at a read voltage of + 2V, and the stored logical value ("1" or "0") could be read out in 30 min. 相似文献
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我们在端点化合物LaFeO3中掺入Cr^3 ,制备了LaFe1-xCrxO3体系的系列样品。经XRD分析证明所制备的样品为单相体系,用MarqX程序对XRD数据进行分析得到其晶格常数。分别测定了入射光子能量在Fe2p吸收边以下和以上的O1s芯能级谱。从电子结构角度探讨了该体系晶体结构变化趋势。初步得出结论:随着Cr^3 掺杂量在LaFe1-xCrxO3中的增加,O2p向Cr 3d的电荷转移量也发生有规律的变化。 相似文献
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