Accuracy of Least Squares Computer Programs: Another Reminder

1976 ◽  
Vol 58 (4_Part_1) ◽  
pp. 757-760 ◽  
Author(s):  
William T. Boehm ◽  
D.J. Menkhaus ◽  
J.B. Penn
1986 ◽  
Vol 1 (2) ◽  
pp. 64-77 ◽  
Author(s):  
Howard F. McMurdie ◽  
Marlene C. Morris ◽  
Eloise H. Evans ◽  
Boris Paretzkin ◽  
Winnie Wong-Ng ◽  
...  

The following new or updated patterns are submitted by the JCPDS Research Associateship at the National Bureau of Standards. The patterns are a continuation of the series of standard X-ray diffraction powder patterns published previously in the NBS Circular 539, the NBS Monograph 25, and in this journal. The methods of producing these reference patterns are described in this journal, Vol. 1, No. 1, p. 40 (1986).The data for each phase apply to the specific sample described. A sample was mixed with 1 or 2 internal standards: silicon (SRM640a), silver, tungsten, or fluorophlogopite (SRM675). Expected 2-theta values for these standards are specified in the methods described (ibid.). Data from which the reported 2-theta values were determined, were measured with a computer controlled diffractometer. Computer programs were used to locate peak positions and calibrate the patterns as well as to perform variable indexing and least squares cell refinement. A check on the overall internal consistency of the data was also provided by a computer program.


1978 ◽  
Vol 22 ◽  
pp. 337-342
Author(s):  
Colin G. Sanderson

Least squares computer programs have been used for the resolution of complex gamma-ray spectra obtained from NaI(Tl) detectors for many years. With the addition of computer codes, which account for the differences “between gamma-ray and x-ray fluorescence spectra, these same programs can be used to quantify energy dispersive x-ray fluorescence data.


1986 ◽  
Vol 1 (3) ◽  
pp. 265-275 ◽  
Author(s):  
Howard F. McMurdie ◽  
Marlene C. Morris ◽  
Eloise H. Evans ◽  
Boris Paretzkin ◽  
Winnie Wong-Ng ◽  
...  

The following new or updated patterns are submitted by the JCPDS Research Associateship at the National Bureau of Standards. The patterns are a continuation of the series of standard X-ray diffraction powder patterns published previously in the NBS Circular 539, the NBS Monograph 25, and in this journal. The methods of producing these reference patterns are described in this journal, Vol. 1, No. 1, p. 40 (1986).The data for each phase apply to the specific sample described. A sample was mixed with one or two internal standards: silicon (SRM640a), silver, tungsten, or fluorophlogopite (SRM675). Expected 2-theta values for these standards are specified in the methods described (ibid.). Data, from which the reported 2-theta values were determined, were measured with a computer controlled diffractometer. Computer programs were used to locate peak positions and calibrate the patterns as well as to perform variable indexing and least squares cell refinement.


1986 ◽  
Vol 1 (4) ◽  
pp. 334-345 ◽  
Author(s):  
Howard F. McMurdie ◽  
Marlene C. Morris ◽  
Eloise H. Evans ◽  
Boris Paretzkin ◽  
Winnie Wong-Ng ◽  
...  

The following new or updated patterns are submitted by the JCPDS Research Associateship at the National Bureau of Standards. The patterns are a continuation of the series of standard X-ray diffraction powder patterns published previously in the NBS Circular 539, the NBS Monograph 25, and in this journal. The methods of producing these reference patterns are described in this journal, Vol. 1, No. 1, p. 40 (1986).The data for each phase apply to the specific sample described. A sample was mixed with one or two internal standards: silicon (SRM640a), silver, tungsten, or fluorophlogopite (SRM675). Expected 2-theta values for these standards are specified in the methods described (ibid.). Data, from which the reported 2-theta values were determined, were measured with a computer controlled diffractometer. Computer programs were used to locate peak positions and calibrate the patterns as well as to perform variable indexing and least squares cell refinement. A check on the overall internal consistency of the data was also provided by a computer program.


1985 ◽  
Vol 29 ◽  
pp. 185-192
Author(s):  
William R. Clayton

A series of computer programs have been written (collectively called XRDQUAL) for automated identification of XRD patterns. The algorithms used in XRDQUAI, have been selected for maximum compatibility with computerbased calculations and decisions, XRDQUAI relies heavily on probabilistic logic and calculations. The overall sequence used can be divided into three general steps.


1983 ◽  
Vol 17 (12) ◽  
pp. 890-893 ◽  
Author(s):  
Andrea Messori ◽  
Tommaso Valenza ◽  
Gaetano Zaccara ◽  
Graziano Arnetoli ◽  
Carlo Bartoli ◽  
...  

A programmable calculator procedure allowing nonlinear least-squares fit to pharmacokinetic data conforming to the Michaelis-Menten model is described. Model parameter estimation is performed according to the iterative Gauss-Newton technique as modified by Hartley. This procedure thus employs the same theoretical approach used by most pharmacokinetic computer programs. No programming skill is needed to run the program described. The proposed procedure is discussed in detail and applied to some sets of pharmacokinetic data.


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