排序方式: 共有32条查询结果,搜索用时 593 毫秒
1.
2.
Effect of experimental conditions on the possibility of formation of multidimensional images of motor fuels and liquid mineral technical oils used for the classification and identification of these samples by the method of pattern recognition is studied. Transmission spectra are considered as primary images of the studied samples. Multidimensional statistical analysis of the results of spectroscopic measurements is performed by principal component analysis. A noticeable increase in the separation of spectroscopic images on the statistical plane in the optimization of the spectral range of the primary image and the thickness of the absorbing layer is shown. 相似文献
3.
4.
提出了强拟Armendariz环的概念,给出了强Armendariz环和强拟Armendariz环上的一些结果. 相似文献
5.
6.
Egorova N. I. Konyushenko I. O. Nemets V. M. Peganov S. A. 《Optics and Spectroscopy》2020,128(4):553-561
Optics and Spectroscopy - The features and possibilities of absorption molecular spectroscopy of complex mixtures of organic compounds have been studied by the example of fractions of thermal... 相似文献
7.
怀菊花中微量铁的测定 总被引:5,自引:3,他引:2
为探讨邻二氮菲分光光度法测定怀菊花中微量元素铁含量的可行性,怀菊花的药理功效、食用营养价值与微量元素含量可能存在的关系,根据铁离子与特定显色剂显色产生可见吸收,采用混合酸y(HNO3):V(HClO4)=4+1对怀菊花样品湿法消化处理,在pH2~9的溶液中试剂与铁生成稳定的橙色络合物,并用分光光度法测定了怀菊花中微量元素铁含量。结果表明,所选的怀菊花中铁含量303.9~337.9μg/g,加标回收率为90.2%~100.6%。分光光度法操作简便、干扰离子少,测量快速、结果准确度和灵敏度高,易推广和 普及使用。 相似文献
8.
9.
Elena N. Konyushenko Miroslava Trchová Jaroslav Stejskal Irina Sapurina 《Chemical Papers》2010,64(1):56-64
Conditions of polyaniline (PANI) nanotubes preparation were analyzed. Aniline was oxidized with ammonium peroxydisulfate in
0.4 M acetic acid. There are two subsequent oxidation steps and the products were collected after each of them. At pH > 3,
neutral aniline molecules are oxidized to non-conducting aniline oligomers. These produce templates for the subsequent growth
of PANI nanotubes, which takes place preferably at pH 2–3. At pH < 2, granular morphology of the conducting PANI is obtained.
High final acidity of the medium should be avoided in the preparation of nanotubes, e.g., by reducing the amount of sulfuric
acid which is a by-product. Reduction of the peroxydisulfate-to-aniline mole ratio was tested for this purpose in the present
study. Lowering of the reaction temperature from 20°C to −4°C had a positive effect on the formation of nanotubes. 相似文献
10.
丝瓜中维生素C含量的测定 总被引:1,自引:0,他引:1
为建立丝瓜中维生素C含量直接测定的新方法,以10%盐酸溶液为溶剂,采用紫外分光光度法测定其含量。结果表明,维生素C在0~10 mg/L质量浓度范围内与吸光度呈良好的线性关系,回归方程为:y=0.047 46ρ+0.001 09,r=0.999 7。检出限为0.023μg/mL,加标回收率在90.6%~99.0%之间。该法操作简单,结果准确,应用于维生素C含量的测定,结果准确,令人满意,可作为控制维生素C质量的方法。 相似文献