43 resultados para Ações (Finanças) - Preços - Previsão


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本文将自模型曲线分辨方法(SMCR)应用于ICP-AES谱线重叠光谱干扰的校正,并就测量误差对重叠光谱解析结果的影响作了详细的研究和讨论。两谱线的重叠程度越大,随机误差对光谱干扰校正的影响越大。对测量数据作平滑处理。可以减小数据随机误差对结果的影响,但平滑次数增加,将导致光谱图变形,使干扰校正结果产生较大的误差。数据的平滑不能减小光谱偏离加和性的误差。本工作对两条光谱重叠的情况作了讨论,并取得了较好的结果,表明SMCR法是校正ICP-AES中重叠谱线干扰的一种简便、快速的方法。

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本文对ICP-AES分析中2种线性回归方法的校准曲线作了比较和讨论。对大多数元素而言,用加权法得到的校准曲线的斜率比不加权校准曲线的斜率略大,减小3校准曲线在低浓度部分的弯曲,曲线明显优于不加权校准曲线。将2种方法得到的校准曲线进行比较时,应将剩余标准偏差(或剩余变差平方和)及曲线截距等加以综合考虑。用含零标的标准系列制作校准曲线可使曲线的截距更接近原点,有利于提高在低浓度部分校准分析的准确性。

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本文研究了以流动注射进样的ICP-AES分析方法和NaCl的基体效应。0.25-2.5%NaCl对11个元素的影响结果表明,FI进样可克服常规连续雾化的信号漂移,从而改善了测量精度。不同功率下的NaCl基体的影响不同。结果表明,NaCl的基体效应主要存在于气溶胶微粒在ICP中的蒸发—原子化—激发过程。

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A method of analysis of high purity yttrium oxide with ICP-AES was described with emphasis on the study of Y_2O_3 matrix effects. The results showed that the line intensities of ana]ytes decreased with the increase of Y_2O_3 concentration in solution because of following factors. (1) The presence of matrix resulted in the decrease of the amount of analytes reaching ICP. (2) Matrix Y_2O_3 entering the plasma decreased the excitation temperature of the plasma and depressed the ionization of analytes in the pl...

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本文采用VG ESCALAB MK-Ⅱ电子能谱仪对多层结构的薄膜Cu_2S-CdS太阳电池进行了X-光电子能谱、俄歇电子谱和深度分析。指出了电池表面的组成、结构和状态。由于制备工艺和处理方法的不同,电池表面和界面会发生变化,从而影响薄膜Cu_2S-CdS太阳电池的电性能和稳定性。本文为电池机理的研究提供了一些数据。

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本工作利用一种改进型旋流雾室雾化氢化物发生装置,建立同时测定铅、砷、锑、铋、锗、锡及非氢化物元素的ICP-AES法。溶液中的Pb(Ⅱ)首先以H_2O_2-(NH_4)_2S_2O_8溶液氧化为Pb(Ⅳ),然后再与NaBH_4溶液反应产生氢化物,与由气动雾化产生的样品气溶胶一起被导入等离子体中。Pb,As,Sb,Bi,Sn,Ge的检出限分别为1.4,7.6,2.8,1.3,2.4和15μg/L,较通常的气动雾化法低20-60倍,硒、碲在氧化剂存在下不能产生氢化物。研究了共存元素的干扰及消除方法。实际样品(沉积物)分析结果与推荐值吻合。

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本文研究了ICP-AES法测定高纯氧化铥中十四种其它稀土杂质的方法。研究了有机溶剂的影响,加热去溶效果等。确定了折衷工作条件。本方法可以测定99.99%高纯氧化铥中十四种稀土杂质,回收率为82.5-110%相对标准偏差为1.9-9.3%。

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本文结合溶剂萃取研究了非水介质中氢化物发生-ICP-AES的分析条件、干扰等因素的影响。利用KI~+H_2SO_4/MIBK萃取体系将As,Sb,Bi萃取到MIBK中而与基体元素分离,然后将该有机相与甲酸按等体积混合后,即可直接进行氢化物发生-ICP-AES分析。还对影响萃取和氢化物发生的一些因素及共存元素的干扰进行了讨论。该方法应用于Ni-Fe基合金中As和Sb的分析,取得了较满意的结果。

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An interface of chip-based capillary electrophoresis (CE)-inductively coupled plasma-atomic emission spectrometry (ICP-AES) that is based on cross-flow nebulization has been developed. A polydimethylsiloxane (PDMS) CE-chip with conventional cross channel layout was used. A stainless steel tube was placed orthogonal to the exit of the CE separation channel for cross flow nebulization. A supplementary flow of buffer solution at the channel exit was used to improve nebulization efficiency. Two capillaries were inserted into the CE chip near the inlet of the separation channel for sample and buffer solution injection. Syringe pumps were used to manipulate the flow rate and flow direction of the sample, buffer, and supplementary buffer solution. Peak broadening due to the shape (bulb and tube-shaped) and size of the spray chambers was studied. The smaller tube-shaped spray chamber was used because of smaller peak broadening effect due to aerosol transport. The nebulization and transport efficiency of the CE-ICP interface was approximately 10%. Ba2+ and Mg2+ ions were eluted from the CE-chip within 30 s. Resolution of the Ba2+ and Mg2+ peaks was 0.7 using the chip-based CE-ICP-AES system.