利用背散射电子图像法定量分析水泥组分含量

在分析了水泥成品的组成成分、各组成成分的平均原子序数等的基础上,提出了用扫描电镜的背散射电子成像法对水泥成品的组分进行定量分析的新方法。结果表明,该方法可直观地反应水泥成品的组分含量。     

Quantitative determination of mesophase content in pitch

A quantitative microscopy method for measuring the mesophase content in pitch has been developed because conventional solubility methods often do not reflect mesophase contents accurately. The general technique utilizes area measurements on photomicrographs of polished specimens to determine volume percent mesophase. Slight modifications to the general method are necessary to overcome unique problems associated with measurements on low (0–15%), intermediate (15–70%) and high (70–100%) mesophase content pitches. Typical data are presented for samples from each regime. The limitations of the method are discussed.     

Determination of the mineral-matter contents of coals by low-temperature ashing

A new method is described for determining the mineral-matter content of coals, based on low-temperature ashing in an oxygen plasma. Unwanted side-reactions can occur during ashing, particularly oxidation of pyrite to haematite and fixation of organic sulphur as sulphate. These effects cannot be totally eliminated, but procedures are offered that minimize them, and are presented as accurate and rapid means of determining the mineral-matter content of bituminous coals. Data are presented to illustrate the magnitude of the effects under the recommended conditions of ashing. Duplicate determinations of the mineral-matter contents of 13 coals by acid demineralization and low-temperature ashing are reported in support of the new procedures. Statistical analysis of the data shows that the precision (± 2 standard deviations) of the LTA procedure under the defined conditions is 0.20. Acceptance of the procedure is suggested for routine use with most coals of bituminous or anthracite rank. The procedure as proposed is unsuitable for use with HVC coals from Western provinces of the USA or with lignites and subbituminous coals.     

灰分计价与发热量计价临界值的合理确定

探讨了在动力煤计价时 ,为实现销售收入最大化 ,要合理确定灰分计价与发热量计价的临界值。     

原子吸收法测定煤灰中镁含量的不确定度评定

通过对原子吸收法测定煤灰成分中镁含量的测量不确定度评定,对测量过程各分量建立了对应的数学模型,量化了各相对不确定度,并最终合成了标准不确定度和扩展不确定度。     

Quantitative determination of the vinylacetate content in ethylene vinyl-acetate copolymers—a critical review

The various methods for the determination of the vinylacetate (VA) content in any ethylene vinylacetate copolymer are examined critically. Each available method is described briefly, together with its relative accuracy. All methods give comparable results and are equally valid, but IR spectrometry can be considered the most flexible and accurate VA content measuring technique.     

测定煤中全硫含量的实验研究

研究了如何利用国产一体化定硫仪准确测定煤中全硫含量的方法。该法基于库伦滴定法测定煤中硫含量,对测量数据的精密度和准确度进行了检验。结果表明,用该方法测量高硫煤时的相对标准偏差为1.39%,测量低硫煤时的相对标准偏差为2.75%,精密度和准确度均符合质量控制要求,且测定速度快,值得推广应用。     

Quantitative determination of the low-molecular fraction content of spinning solutions of poly-meta-phenyleneisophthalamide

Conclusions A method for the quantitative determination of low-molecular fraction content in spinning solutions of poly-meta-phenyleneisophthalamide in dimethylacetamide has been established and developed using UV-spectroscopy; this is a basic procedure.The effect of the composition of the reaction mixture on the LMF content of the spinning solution has been shown.VNIISV, Tver'. Translated from Khimicheskie Volokna, No. 2, pp. 17–19, March–April, 1992.     

浅谈跳汰选煤矸石带煤的检测与改进

针对入洗原煤可选性逐渐变差 ,采用传统的跳汰工艺分选越来越困难 ,矸石带煤损失增多的状况 ,为了减少精煤损失 ,将过去采用的 1 4kg L密度液检测带精煤损失改为以 1 7～1 8kg L密度液检测中煤、精煤损失情况 ,及时指导洗煤司机的操作 ,取得了较好的效果     

采用图像分析技术测定黑素细胞中黑素含量

采用图像分析技术，建立了细胞中黑素含量的测定方法，以适应美白化妆品研究开发的需要。结果显示：改进后的方法，精确度测试的变异系数均值为1.2%，准确度测试，相关系数为0.91054。稳定性测试，方差分析无显著性差异。提示本法精确、准确、稳定、简便和经济，适用于美白化学物的研究开发。     

Quantitative determination of the monoclinic crystalline phase content in polyethylene by 13C n.m.r.

Solid-state ¹³C n.m.r. spectroscopy involving the techniques of cross-polarization (CP), magic angle spinning (MAS), and high power proton decoupling, has been used to determine quantitatively the ratio of monoclinic to orthorhombic crystalline phases in compression moalded ultra-high molecular weight polyethylene (UHMWPE) sheet which had been stretched uniaxially. Criteria for expecting quantitative relative intensities in ¹³C CP-MAS spectra are discussed. Attenuation of the non-crystalline (NC) signals relative to crystalline signals was observed. Experiments were therefore carried out to ascertain whether measurable relative intensity distortions exist between the monoclinic crystalline phase (MCP) and the orthorhombic crystalline phase (OCP) resonances due to possible differences in proton ‘spin diffusion’ between the NC and the two crystalline phases during cross-polarization. No relative intensity distortions were detected. This result, coupled with experiments in which spin diffusion was monitored at times longer than those used for cross-polarization, suggests that the average distance from the protons in a given crystalline phase to the nearest protons in the NC regions is the same for the MCP and the OCP. Finally, non-spinning ¹³C spectra of the deformed polyethylene were recorded to determine the orientation of the chains in the crystalline and NC regions. The Hermans orientation function, F_c, was determined independently for the crystalline (combined OCP and MCP) and NC regions, and found to be 0.66 + 0.06 and 0.23 + 0.04 respectively. The occurrence of orientation in the NC regions may be evidence for internal stresses, which, it is suggested, also stabilize the metastable MCP in the stretched sample.     

元素分析仪测定煤质样品C、H、N含量的不确定度评定

采用元素分析法测定煤样C、H、N元素含量,讨论了在测定过程中由测量重复性、样品不均匀性等因素产生的不确定度,计算了煤样C、H、N元素含量的合成标准不确定度和扩展不确定度。结果表明,C、H、N含量的扩展不确定度均小于0.5%。     

Monitoring the sulfur content of coal

Information regarding the sulfur content of the coal is required not only in metallurgy but also when burning coal as a fuel. The traditional method of determining the sulfur content of coal is unsuitable for large-scale monitoring of processes because it is laborious and not sufficiently reliable. Nuclear-physics methods are free of those problems. However, satisfactory precision of the results is only possible with relatively constant composition of the coal or when the matrix effect due to fluctuations in the composition is taken into account. In the present work, the composition of coal is studied by correlation and regression analysis of the ash composition in coal from different deposits. The correlation coefficients between the main ash components (Al₂O₃, SiO₂, SO₃, CaO, and Fe₂O₃) are calculated. For the example, of coal from Kazakhstan and the Minusinsk Basin, statistically significant correlations are established between the contents of sulfur and calcium in the coal; the correlation coefficient is 0.75–0.93. No significant and consistent correlations are found between other ash components. These findings permit optimal development of nuclear-physics methods of monitoring the sulfur content of coal—specifically, in improving the precision of the analysis by taking account of the matrix effect due to redistribution of the mineral components.     

Quantitative determination of total lipid hydroperoxides by a flow injection analysis system

A flow injection analysis (FIA) system coupled with a fluorescence detection system using diphenyl-1-pyrenylphosphine (DPPP) was developed as a highly sensitive and reproducible quantitative method of total lipid hydroperoxide analysis. Fluorescence analysis of DPPP oxide generated by the reaction of lipid hydroperoxides with DPPP enabled a quantitative determination of the total amount of lipid hydroperoxides. Use of 1-myristoyl-2-(12-((7-nitro-2-1,3-benzoxadiazol-4-yl)amino) dodecanoyl)-sn-glycero-3-phosphocholine as the internal standard improved the sensitivity and reproducibility of the analysis. Several commercially available edible oils, including soybean oil, rapeseed oil, olive oil, corn oil, canola oil, safflower oil, mixed vegetable oils, cod liver oil, and sardine oil were analyzed by the FIA system for the quantitative determination of total lipid hydroperoxides. The minimal amounts of sample oils required were 50 μg of soybean oil (PV=2.71 meq/kg) and 3 mg of sardine oil (PV=0.38 meq/kg) for a single injection. Thus, sensitivity was sufficient for the detection of a small amount and/or low concentration of hydroperoxides in common edible oils. The recovery of sample oils for the FIA system ranged between 87.2±2.6% and 102±5.1% when PV ranged between 0.38 and 58.8 meq/kg. The CV in the analyses of soybean oil (PV=3.25 meq/kg), cod liver oil (PV=6.71 meq/kg), rapeseed oil (PV=12.3 meq/kg), and sardine oil (PV=63.8 meq/kg) were 4.31, 5.66, 8.27, and 11.2%, respectively, demonstrating sufficient reproducibility of the FIA system for the determination of lipid hydroperoxides. The squared correlation (r ²) between the FIA system and the official AOCS iodometric titration method in a linear regression analysis was estimated at 0.9976 within the range of 0.35−77.8 meq/kg of PV (n=42). Thus, the FIA system provided satisfactory detection limits, recovery, and reproducibility. The FIA system was further applied to evaluate changes in the total amounts of lipid hydroperoxides in fish muscle stored on ice.     

Reducing the sulfur content of coke by increasing the content of thermally conditioned g coal in the batch

In periods of economic growth, Ukrainian coke plants face a shortage of Zh and K coal, because of the high demand. In periods of economic stagnation, conversely, there is an excess of Zh coal, on account of the drop in demand. However, it is still important to introduce poorly clinkering coal in the batch. Ukrainian coal is known to have high sulfur content (up to 3.5% S). About 45–75% of that sulfur is passed on to the coke. Consequently, in order to reduce the sulfur content of the coke, it is expedient to include poorly clinkering coal in the batch, since typical low-carbon Donets Basin coal has a low desulfurization coefficient: 0.63. The corresponding figure for moderate-carbon coal is 0.70. Hence, by increasing the content of poorly clinkering coal in the batch, the sulfur content and cost of the coke may be reduced.     

用HPLC法测定硫化胶中游离硫磺的含量

最近提出了一种新的定量分析方法来定量天然橡胶硫化胶中的游离硫磺。这个方法是先用四氢呋喃(THF)萃取,然后,再用HPLC法来定量游离硫磺。比起亚硫酸钠法,它不需要很多的试样,灵敏度却比以前的方法高出了数百倍。另外,它只能对非键合的单体硫磺进行定量,这一点与亚硫酸钠法所定量的值有所不同。     

Analysis of the microelement content in coal

Microelements are present in coal in its organic matter, mineral impurities, and biochemical material. The microelement content in these components will be different, on account of the different forms of migration and access to the organic system. Estimation of the microelement content in the basic components of the coal is of interest in terms of assessing the rare-metal content in coal fields and extracting those metals. Statistical analysis of the microelement contents in different components of the coal is proposed.