ISSN:0049-8246    

DOI:10.1002/xrs.1300190202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

ISSN:0049-8246    

DOI:10.1002/xrs.1300190203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractAlthough the present‐day x‐ray analyst has at his or her disposal a sufficient variety of instrumentation and data reduction schemes to enable him or her to perform elemental analysis on many different types of materials, there exists a continuing demand to improve detection limits, to extend the capability to lower atomic numbers and to make the analytical process more efficient (easier!). There are advances in x‐ray physics and instrumentation being pursued which may contribute to these objectives. The status of these efforts is reviewed and some suggestions are made concerning their pote

ISSN:0049-8246    

DOI:10.1002/xrs.1300190204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractResults obtained using synchrotron radiation as an excitation source for energy‐dispersive analysis are reviewed. Practical experience gained in the use of tunable, monochromatic excitation for trace analysis of various types of samples is discussed. Advantages and limitations associated with specific synchrotron radiation properties are evaluated. In particular, the influence of multiple inelastic scattering and resonant Raman scattering on limiting the degree of detectability improvements associated with energy tuning is demonstrated. A scanning x‐ray microprobe employing multilayer mirrors as focusing elements is described. Measurements performed with this system have demonstrated the capability of detecting femtogram quantities of trace elements in a 10 × 10 μm

ISSN:0049-8246    

DOI:10.1002/xrs.1300190205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractSharp negative lines have been observed in wavelength‐dispersive (WD) spectra. These ‘holes’ can cause severe errors when analysing for trace elements near the lower levels of detection. The existence of the holes is explained in terms of diffraction from crystailographic planes other than those used in the WD analysis, and an overview is given of the theory necessary to predict the occurrence of the holes with emphasis on LiF(200) analysing cry

ISSN:0049-8246    

DOI:10.1002/xrs.1300190206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractA method is described for the determination of S6+(sulphate) and Sc(C—S bonded sulphur) in plant material by x‐ray fluorescence spectrometry which is considerably more simple and rapid than the chemical determinations of the corresponding sulphur fo

ISSN:0049-8246    

DOI:10.1002/xrs.1300190207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractA method is described for the XRS fusion analysis of mineral and plant concentrates containing sulphides (e.g. PbS, ZnS, CuFeS2and FeS2) together with slags, mattes, fumes and drosses. The method involves a short pre‐oxidation treatment using sodium nitrate, followed by fusion with an appropriate heat source. Losses of S by volatilization and of metals into the platinum crucibles are acceptably small for general assay purpose

ISSN:0049-8246    

DOI:10.1002/xrs.1300190208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe production, properties and structure of II–VI semiconductor materials are topics of increasingly intense research activity. This paper discusses the use of the surface analytical techniques x‐ray photoelectron spectroscopy, Auger electron spectroscopy and energy‐dispersive x‐ray spectroscopy to study and characterize these materials, and hence assist in understanding the growth

ISSN:0049-8246    

DOI:10.1002/xrs.1300190209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractCdTe and HgCdTe epitaxial layers were grown on 50 mm diameter (100) GaAs wafers in a Quantax 226 metallo‐organic chemical vapour deposition system. Dimethylcadmium, diethyl telluride and elemental mercury were used as starting materials in the thermal growth process which takes place in a flow of hydrogen at 250–350°C. The layers were characterized by (1) an interference contrast microscope for surface morphology; (2) FTIR spectros‐copy for compositional and thickness uniformity; (3) x‐ray topography and double crystal diffractometry for the non‐destructive evaluation of the crystalline quality and microstructure; (4) energy‐dispersive x‐ray analysis (WDX/EDX) for compositional studies; (5) transmission electron microscopy for interface observations and analysis; and (6) Rutherford backscattering and channelling analysis for surface stoichiometry and crystal quality

ISSN:0049-8246    

DOI:10.1002/xrs.1300190210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractThe importance of Standard Reference Materials (SRMs) or Certified Reference Materials (CRMs) in quality assurance of measurements is widely accepted. SRMs and CRMs are frequently used in analytical chemistry for calibration, verification and evaluation of both analytical methods and instruments. The homogeneity, means of certification, stability and uncertainty of certified values for SRMs or CRMs are of particular interest. As one of the main techniques of elemental analysis, x‐ray fluorescence (XRF) analysis plays an important role in homogeneity tests and certification measurements for SRMs and CRMs. The XRF procedures for analysing Tibet Soil and Chinese Tea CRMs are presented as examples. The results obtained by XRF are in good agreement with the certified values or those from using other analytical techniques and from the different laboratorie

ISSN:0049-8246    

DOI:10.1002/xrs.1300190211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY