资料摘要
资料下载Vitamin E or a-tocopherol is a well-known antioxidant that is added to many foods to reduce oxidation. It is also marketed in vitamin formulas and as a nutraceutical. Many natural products such as soybeans, corn, safflowers, peanuts, wheat germ and sunflowers contain tocopherols in low concentration. Because of the high market value placed on natural tocopherols, their isolation from natural sources in a highly purified form is desired. The oily nature of these natural product matrices creates problems when isolating tocopherols. Direct injections of neat oil or oil dilutions of natural products onto reversed phase HPLC columns cause many problems including coating the stationary phase with lipids that leads to ghost peaks, unstable baselines and short lifetimes. Using reversed phase flash chromatography as the preliminary isolation step allows the tocopherols to be concentrated and have fewer oils as contaminants thereby increasing the lifetime of the HPLC columns.
大电流电解水制氢过程中的交流阻抗测试
简介:大电流电解水制氢过程中的交流阻抗测试
从Nyquist图中准确地识别欧姆电阻
简介:电池的内阻包括欧姆电阻和极化电阻。在温度恒定的条件下,欧姆电阻基本稳定不变,而极化电阻会随着影响极化水平的因素变动。 欧姆电阻主要由电极材料、电解液、隔膜电阻及集流体、极耳的连接等各部分零件的接触电阻组成,与电池的尺寸、结构、连接方式等有关 我们都知道欧姆电阻可以通过交流阻抗EIS方法测得,但怎样才能从EIS数据中得到准确的欧姆电阻呢?很多人认为是Nyquist图跟横轴的交点,但其实这样读到的欧姆电阻并不准确。 我们可以用分析软件做个模拟电路或者用电子元件搭建一个简单的电路进行分析。
Tafel极化曲线双向扫描的好处
简介:当我们对材料做Tafel极化曲线测试时会不会有这样的疑问: 为什么极化曲线测出来的腐蚀电位跟开路电位偏差大,以至于阳极部分与阴极部分不一样宽?
Zahner分析软件EIS拟合步骤
简介:Zahner Analysis分析EIS数据的拟合步骤 1.打开EIS.ism的数据 2.打开Model Editor 3.创建等效电路或打开已保存的等效电路文件 4.进行拟合 5.查看拟合情况 6.导出拟合结果
怎样进行Tafel曲线测试和分析?
简介:怎样进行Tafel曲线测试和分析? 1. 选择 LSV方法 (Linear Sweep Voltammetry) 2.设定下列测试参数:相对于开路电位,极化电压扫描范围为-300mV到+300mV,扫描速度为1mV/s。 3.数据分析:用 Zahner Analysis 分析软件打开LSV数据,Plot Presets 设置数据显示方式为log I vs U
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