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分析方法的回收率的计算公式,通常有两种形式: K_1=(A-B)/C×100% (1)式中,A:加入标准物质的样品测得量,B:样品中该物质的测得量,C:加入的标准物质量。 K_2=A/(B+C)×100% (2)式中,A,C的含义同上,B:样品中该物质的“真值”。分析方法的回收率K,可定义为:被测元素的测得量与其理论真值之比,以百分数表示。 K=X/μ×100% (3) 据此,式(1)中A-B是C的测得量,或称 相似文献
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High Performance Long Wavelength Superlattice Photodetectors Based on Be Doped Absorber Region 下载免费PDF全文
The effect of Be doping on the quantum efficiency and the dark current of InAs/GaSb long-wavelength infrared superlattice photodetectors grown by molecular-beam epitaxy on GaSb substrates are reported. A significant improvement of quantum efficiency (QE) with p-type doping is demonstrated. Our results show that Be doping level at 2.5 × 10^15 cm^3 gives the highest quantum efficiency of product 28%. We also demonstrate that the increased QE is not only resulted from the longer minority carrier diffusion length, but also the p-n junction location change. Finally, the result also shows that the sample with a doping density of 2,5 × 10^15 cm^3 has the largest D* as 8.68 × 10^10 cm.Hz^l/2.W^-1, which is almost five times D* of the non-intentionally doped one. 相似文献
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双样分析精密度有多种表达式。本文对准偏差,平均偏差,极差及其应用范围作一简述。使用表达式R=A-B<2.48R作为判据,可以简单和有效地确定常规分析中重复性精密度是否符合要求,重复性精密度的定量定义见中华人民共和国国家标准GB-3358-82。 相似文献
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