大学物理教学中量纲分析与应用

量纲分析是重要的半定量分析方法之一,在大学物理教学实践中,要培养和倡导学生在学习中灵活应用量纲分析解决问题,使教学更丰富和直观.本文介绍量纲分析的基本理论及怎样将量纲分析方法贯穿于教学中.     

X射线荧光无标半定量分析奶粉微量元素

采用X射线荧光光谱半定量分析方法同时检测了奶粉样品中微量元素含量,以奶粉中主要营养成分含量为依据,模拟计算其平均分子式作为平衡项处理。结果表明,采用模拟的平均分子式作为平衡项处理,测定结果与给出的标准值吻合。该法样品处理简单,分析速度快,无需建立校准曲线,方法的准确度符合分析的需要。     

标准溶液配制用碳酸锂纯物质中杂质含量的测定

从高纯碳酸锂中杂质含量测定出发,研讨了标准溶液配制用原料的杂质测定方法,首先利用电感耦合等离子体质谱(ICP-MS)法对高纯碳酸锂进行半定量分析,再依据半定量分析结果选择ICP-MS、电感耦合等离子体原子发射光谱(ICP-AES)法、原子吸收光谱(AAS)法等方法对相应元素(杂质含量0.001%)进行定量分析,通过扣除杂质含量得出高纯碳酸锂纯度大于99.991%。从而建立了一个准确、高效,覆盖元素种类多的高纯物质中杂质含量的分析方法     

A bare-eye based one-step signal amplified semiquantitative immunochromatographic assay for the detection of imidacloprid in Chinese cabbage samples

A novel bare-eye based one-step signal amplified semi-quantitative immunochromatographic assay (SAS-ICA) was developed for detection of the pesticide imidacloprid. This method was based on competitive immunoreactions. Signal amplification was achieved by dual labeling of the test lines (TLs) on the strip using high affinity nanogold-biotinylated anti-imidacloprid mAb (BAb) and nanogold-streptavidin (Sa) probes. The relative color intensities of three TLs (TL-I, TL-II and TL-III) on a nitrocellulose (NC) membrane were used for direct visual analysis of the SAS-ICA strips, and could be used for semi-quantitation of analyte concentrations by observing what TLs disappeared in the amplification zone. Under optimized conditions, the following imidacloprid concentration ranges would be detected by visual examination of the SAS-ICA strip: 0–5 ng mL⁻¹ (negative samples), and 5–25 ng mL⁻¹, 25–250 ng mL⁻¹, 250–1000 ng mL⁻¹ and >1000 ng mL⁻¹ (positive samples). The sensitivity (the visual detection limit (VDL) of TL-III) and semi-quantitative analytical capacity (when TL-III disappeared completely) of the SAS-ICA strip were 10-fold and 160-fold higher than those of traditional ICA, respectively. The developed SAS-ICA strip was applied to the analysis of spiked and authentic contaminated Chinese cabbage samples in the laboratory and under field conditions, and the results were validated by high-performance liquid chromatography (HPLC). This process could be adopted as a potential generous technique for all ICA-based detection methods.     

运用“颜色识别器”软件探究常见净水剂的净水原理*

盐类水解的应用中铝盐和铁盐的净水作用涉及胶体的生成与吸附聚沉,是一个综合且复杂的化学问题,为发展学生化学学科素养,利用“颜色识别器”软件中色密度(V)值与黄土壤浊液中土壤含量的半定量关系,建构了一种基于课堂教学的快速定量测定工业净水剂净水效果的实验方法,为化学课堂教学中关于盐类水解的具体应用提供了真实情境和探究案例。     

演示实验和文科物理教学

阐述了物理演示实验在高校文科物理教学中的作用、意义及在复旦大学的实施情况．     

An Expert System for EPMA

 Experimental parameters for an electron microprobe are numerous and their choice influence the quality and accuracy of the analysis results. The expert system intends to optimise the choice of every parameter as well as to automate the stages of a quantitative analysis for all kinds of materials. In short, the expert system aims to master the accuracy of results and to control the time of analysis. The starting point of the expert system is an interactive questionnaire about the sample and about the expectations of the analysis (the accuracy of the result and/or the duration of the analysis). Then, the expert system makes a semi-quantitative analysis on the sample. It gives the sample composition in a first approximation. This is necessary for the expert system to optimise all the parameters for an accurate quantitative analysis. Each parameter is modelled by a specific algorithm. The expert system selects the parameters by minimising, at every stage, the statistical error generated by the algorithm. In this way, it operates in a sufficiently independent way to create a quantitative analysis configuration adapted to an unknown sample. The expert system employs the usual methods of quantification but the results are obtained in half the time. Moreover, the accuracy of the result is guaranted by the statistical error calculation as the expert system is running.     

Measurements of contaminant elements of wines by inductively coupled plasma-mass spectrometry: A comparison of two calibration approaches

The aim of the present work was to develop and validate an accurate method by ICP-MS focalized to the measurement of contaminant elements in wines, in special those with legal importance. In addition, we intended to evaluate the suitability of ICP-MS semi-quantitative methodology in order to reduce the time and cost of analysis. Twenty-six contaminant elements of wine (Li, Be, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, In, Cs, Ba, Hg, Tl, Pb, Bi and U) were measured using quantitative and semi-quantitative calibration approaches, in diluted white and red wines. In an early step potential interferences caused by Cl and Ca species were evaluated, in order to establish suitable mathematical corrections. For validation of ICP-MS procedures a few elements were determined by flame and electrothermal AAS. Reference wines from 1992 year, with provisional values, were analyzed and the results showed satisfactory agreement. The semi-quantitative calibration provided slightly higher limits of detection than those obtained by the quantitative calibration, and always lower than 0.1 μg l⁻¹, except for Fe and Zn. For most elements the recovery percentages (between 90 and 100%) and precision of the results (R.S.D. (%) < 4) were similar for both modes. Differences lower than 20% of concentration was obtained for most elements. Both methodologies offer valuable alternatives to wine characterization and comparison purposes. For legal requirements control purposes, with reference to the importance of accurate results, quantitative approach is the most suitable alternative.     

定性与半定量物理实验教学初探

近年来，复旦大学在物理实验教学中适当加入了一批定性与半定量实验，实践证明，该类实验有利于培养学生分析问题与解决问题的能力，增强科学洞察力与判断力，激发他们的求知欲与创新精神，提高其科学素质．本文介绍了开设这些实验的经验、体会及初步效果．     

铈对Al-Li合金断裂方式影响的半定量研究

以2090合金和2090 Ce合金为研究对象, 对两合金不同时效时间的室温拉伸断口进行了半定量分析, 探讨了拉伸性能对断裂特征的响应关系, 并进一步分析了Ce的作用. 研究表明: 2090合金与2090 Ce合金的断裂方式均以韧窝、分层开裂和沿亚晶界开裂3种方式为主, 随时效时间的延长, 韧窝减少; 分层先增加, 后减少; 沿亚晶界开裂比例逐渐加大. 2090 Ce合金的韧窝比例较2090合金的大, 沿亚晶界开裂比例少, 分层开裂始终为主要断裂机制. 分层开裂倾向与时效程度有密切关系. Ce通过净化合金, 强化晶界, 抑制共面滑移达到增塑作用. 但其对抑制共面滑移有双重影响, 使其增塑效应随时效程度不同而异. 欠时效和过时效状态增塑作用较弱, 峰值时效状态作用明显.