钛粉质量鉴定新方法试验研究

钛粉质量鉴定一直是用化学分析测定全钛含量，而不能确定单质态的钛含量，实验表明用Ｘ射线衍射分析鉴定钛粉质量效果较好，避名了化学分析的缺点，是一种值得推广的鉴定方法。     

On-Line Standard Addition Technique for the Determination of Elements in the Samples with High Dissolved Solids by ICP-OES: Application to Determination of Rare Earth Elements in Geological Samples

A simple and rapid on-line standard addition method for analysis of samples with high dissolved solids by ICP-OES is reported. The method involves on-line addition of standard solutions to the sample using a T-piece, prior to the sample introduction system. The standard addition method is commonly used in the analysis of samples with complex matrices. However, the conventional standard addition method is a tedious and time-consuming process. Therefore, in this study, on-line standard addition technique was offered to significantly decrease the analysis time and increase the simplicity of the standard addition method. The performance of the proposed method was tested by determination of rare earth elements in geological samples. This method showed a high level of accuracy in comparison with external calibration and internal standard addition methods.     

有机酸分析的柱后缓冲电导法与紫外法、直接电导法的比较

柱后缓冲电导法采用柱后调节pH值,电导检测器检测的方法检测有机酸,它避免了经常使用的紫外法选择性差,直接电导法灵敏度低的缺点,是可以实现有机酸准确定量的一种新型分析方法.本文比较了这三种方法的分析结果.     

New incremental isoconversional method for kinetic analysis of solid thermal decomposition

A simple and precise incremental isoconversional integral method based on Li-Tang (LT) method is proposed for kinetic analysis of solid thermal decomposition, in order to evaluate the activation energy as a function of conversion degree. The new method overcomes the limitation of LT method in which the calculated activation energy is influenced by the lower limit of integration. By applying the new method to kinetic analysis of both the simulated nonisothermal case and experimental case of strontium carbonate thermal decomposition, it is shown that the dependence of activation energy on conversion degree evaluated by the new method is consistent with those obtained by Friedman (FR) method and the modified Vyazovkin method. As the new method is free from approximating the temperature integral and not sensitive to the noise of the kinetic data, it is believed to be more convenient in nonisothermal kinetic analysis of solid decompositions.     

Determination of nanoparticle sizes by X-ray diffraction

Different procedures for analysis of particle sizes by the X-ray diffraction method are compared by the example of nanoparticles of nickel and iron(3+) oxide (Fe₂O₃). A modified Warren-Averbach method is proposed for the analysis of the X-ray diffraction line profile based on the approximation by the Voigt function, which yields stable solutions, and the efficiency of the method is shown. The analysis within the frame-work of the Warren-Averbach method makes it possible to restore the distribution function of nanoparticles (crystallites) over true diameters, which satisfactorily correlates with electron microscopy data. The applicability of the Warren-Averbach method to the estimation of crystallite sizes by the analysis of a single diffraction line is substantiated. The range of the applicability of the Scherrer, Williamson-Hall, Warren-Averbach, and modified Warren-Averbach methods to the substructure analysis by the X-ray diffraction is determined as depending on the method of nanostructure formation.     

Distribution analysis for single molecule FRET measurement

A new numerical analysis method for experimental single-pair fluorescence resonance energy transfer (sp-FRET) data is proposed. In this method, every single data point was plotted in a style of a cumulative distribution function and dedicated to curve-fitting analysis, so that the analysis does not depend on bin size. A series of numerical simulations showed that this analysis has a more efficient and accurate resolvability of components than a fitting method based on Gaussian functions to a histogram plot. A simulated data based on experimental FRET distributions were also used to discuss the fitting errors of this method. The proposed method was applied to sp-FRET experiments of doubly dye-labeled double-strand DNA with a short sequence. Mixtures of up to three species were analyzed, and the contributions up to four subpopulations were successfully resolved.     

Multiple gamma-ray detection method and its application to nuclear chemistry

A new radionuclide quantification method is proposed on the basis of multiple gamma-ray detection, which is two or higher fold gamma-ray coincidence method. The coincidence method has so far been used for nuclear structure study. We apply this method for quantification of radioactive nuclei. The advantage of this method consists of high energy resolution and high sensitivity. It is successfully applied to nuclear waste analysis, neutron activation analysis and prompt gamma-ray analysis. The principle of the multiple gamma-ray detection method and future perspectives for an innovative pulsed neutron source and a new detector system will be presented.     

Simultaneous determination of antimony and chlorine in synthetic rubbers by 14 MeV neutron activation analysis

A nondestructive method for the analysis of Sb and Cl in synthetic rubbers by 14 MeV neutron activation analysis has been developed and evaluated by comparisons with microanalytical and thermal neutron activation analysis results. The method is most precise when a rubber with known amounts of Sb and Cl is used as a standard. Samples containing 0.07 to 2.5 wt.% Sb and 2.5 to 15.9 wt.% Cl have been analyzed and precision for the method is 10% or better. Antimony and Cl detection limits are 0.02 and 0.5 wt.% respectively. Agreement among the three methods is excellent; the thermal activation analysis method is more precise and simpler to apply if only Sb needs to be determined in a sample. This work was supported by the U.S. Department of Energy (DOE) under Contract DE-AC04-76-DP00789. A U.S. DOE facility.     

Size distribution analysis of polymer latex systems by use of extrema in the angular scattering intensity

The angular position of the extrema of the vertically polarized scattering intensity has previously been utilized for a method of particle size analysis for systems of monodisperse, spherical, isotropic particles which conform to the Rayleigh-Gans-Debye theory. The consequences of a finite polydispersity, which is always present in real systems, was not assessed and the application of the method has resulted in erroneous characterization of some latex systems. This work is concerned with (1) reporting the effects of finite polydispersity on the method of analysis, (2) pointing out previous misuse of the method, and (3) introducing a method of analysis which is based on the position of the extrema but which also considers polydispersity and the exact Mie calculation. This method enables one to characterize a scattering system in terms of a modal diameter and a distribution-width parameter by utilizing prepared diagrams for a particular relative refractive index.     

一个基于诊断的稳健主成分分析方法

经典的主成分分析方法易受异常点影响。本文根据该方法的特点，提出一新的诊断方法，将多变量数据中异常剔除后再进行主成分分析，构成有效的稳健主成分分析法。用此法处理二组实际数据，结果令人满意。     

机械润滑油中含水量的高速分析

因生产现场需要，试验在参照国外气量法快速测定润滑油含水量的基础上，用自制的设备进行试验，成功地摸索出一种高速分析方法，整个反应过程中在３ｍｉｎ２０ｓ内结束。通过对含水量压力之间相互关系的回归分析，得到几种机械润滑油可共同适用的回归方程，总结出温度变化对试验结果的影响，并通过与蒸馏法的平行比较，验证了方法的先进和可行笥。     

Determination of carrier yields for neutron activation analysis using energy dispersive X-ray spectrometry

A new method is described for determining carrier yield in the radiochemical neutron activation analysis of rare-earth elements in silicate rocks by group separation. The method involves the determination of the rare-earth elements present in the carrier by means of energy-dispersive X-ray fluorescence analysis, eliminating the need to re-irradiate samples in a nuclear reactor after the gamma ray analysis is complete. Results from the analysis of USGS standards AGV-1 and BCR-1 compare favorably with those obtained using the conventional method.     

Potentiometric titrations using dual microband electrodes.

We present a novel method of analysis using potentiometric end-point detection and dual microband electrodes in generator-collector mode. The titrant is electrogenerated using either a constant current or a current that increases linearly with time, and the fluxes of reactive material rather than molar amounts are balanced. The advantage of the ramp current system over the constant current method is that all of the information needed for a full titration curve and a proper analysis can be obtained during a single scan. The method was applied to the determination of vitamin C with ferricyanide and to the determination of thiosulfate and sulfite with iodine using gold microband electrodes. As a new type of analysis, a potentiometric titration that uses dissolving silver microband electrodes in order to generate the titrant is demonstrated. The system was applied to the detection of chloride, iodide, thiosulfate and cyanide. The accuracy of the analysis is +/-10%, limited mainly by the present screen-printing process, and the method is well adapted for measurements on the millimolar scale.     

Size-distribution analysis of polymer latex systems by use of the extrema in the angular light-scattering pattern: II. The polarization ratio

Previously, the angular positions of the extrema of the polarization ratio have been utilized in light-scattering studies as a method of particle-size analysis under the assumption of monodisperse, spherical particles. Since the consequences of the existing finite polydispersity on this method of analysis was not assessed, the results are questionable. This work is concerned with (1) reporting the quantitative effects of a finite polydispersity on the method of analysis, (2) pointing out previous misuse of the method, and (3) revising the method of analysis to include polydispersity and the exact Mie calculations. The method will then permit the characterization of a scattering system in terms of a modal diameter and a distribution-width parameter by utilizing prepared diagrams for a particular relative refractive index.     

Further modification of a fluorometric method for analyzing brain amines

A method is presented for the fluorometric analysis of serotonin, norepinephrine, and dopamine. The method is relatively easy, relatively fast, and uses manageable sample volumes. The method has the additional advantage of saving 1/3 the time, compared to the time involved to accomplish a similar analysis that was reported previously.     

高效液相色谱多波长定性方法研究

介绍了高效液相色谱法中除常用的保留时间和光谱图定性以外的另一方法──多波长定性分析方法。根据Beer's定律可知,同一化合物在不同波长下测得的峰面积之比为定值。利用高效波相色谱多波长同时检测的方法,比较化合物在不同波长下的峰面积大小,建立了简便的定性方法,并在禁用假氮染料测定时对18种芳香腔的定性分析中得到成功的应用。     

Molecular mass analysis of antibodies by on-line SEC-MS

Mass analysis of recombinant protein therapeutics is an important assay for product characterization. Intact mass analysis is used to provide confirmation of proper translation of the DNA sequence and to detect the presence of post-translational modifications such as amino acid processing and glycosylation. We present here a method for the rapid mass analysis of antibodies using a polyhydroxyethyl aspartamide column operated in size-exclusion mode and coupled with ESI-MS. This method allows extremely efficient desalting of proteins under acidic conditions that are optimal for subsequent mass analysis using standard ESI conditions. Furthermore, this technique is significantly faster and more sensitive than rpHPLC methods, typically considered the standard chromatography approach for mass analysis of proteins. This method is flexible and robust, and should prove useful for applications where a combination of speed and sensitivity are required.     

Mixed mode chromatography via column switching for the simultaneous HPLC analysis of lonic and non-lonic nucleic acid constituents

Summary A method is presented for the separation of purine and pyrimidine nucleotides, nucleosides and bases in one analysis. This method uses both the ion-exchange and the reversed-phase modes for the analysis of these compounds. The modes are coupled through automatic switching valves. The use of these valves permits the isolation of either column during the analysis. The nucleotides are separated on an anion-exchange column and the nucleosides and bases on a C-18 column. Total analysis time is approximately one hour, and a very small volume of a sample can be analyzed. The technique is flexible and mobile phase conditions for one column can be altered without affecting the resolution on the other column. The method is applicable to biological matrices.     

小波变换结合多维偏最小二乘方法用于近红外光谱定量分析

将小波变换和多维偏最小二乘法相结合用于近红外光谱定量校正模型的建立。首先将原始光谱进行小波变换分解，得到系列小波细节系数，通过选取一组受外界因素少、信息强的小波系数组成三维光谱阵，然后再采用多维偏最小二乘法建立校正模型。实验结果表明，该方法所建近红外校正模捌的预测能力更强，并更具稳健性。