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151.
Pierre Parisot 《商业与工业应用随机模型》1985,1(1):35-54
We studied a population of paraplegic patients in order to give prominence to a possible relationship between the topography of their spinal lesion and the occurrence of special articular diseases (P.O.A.). According to the motor and sensory state of their spinal cord, we first tried to obtain a classification of these lesions (the usual one schematically separates ‘flaccid’ and ‘rigid’ paraplegics). We mainly put the emphasis on this clustering step of the study:
- 相似文献
152.
Summary Gas chromatographic retention indices for 47 C5 to C8 alkenes on OV-101 dimethylsilicone at 50 and 70 °C were determined within a standard deviation of 0.3i.u. Data obtained on
OV-101 are compared with those measured on squalane. The comparison of the retention index and dl/dT values from both columns
is presented as linear regression equations with correlation coefficients greater than 0.98. 相似文献
153.
固定pH滴定法测定弱酸弱碱性药物 总被引:8,自引:0,他引:8
报道一种水溶液吕测定弱酸弱碱性药物的新型滴定分析方法-固定pH滴定法,其理论基础是弱酸弱碱在水溶液中各种存在形式的分布系数在pH值固定时为常数,对甲硝唑,盐酸美西律等离散常数在10^-8至10^-11范围内的7种弱酸弱碱性药物进行测定。结果与药典法吻合,回收率在99.4%~100.6%,方法简便,快速,准确,制剂中的赋形剂及色物不影响测定。 相似文献
154.
155.
《Surface and interface analysis : SIA》2004,36(10):1373-1383
An error analysis for numerically evaluating random uncertainties in x‐ray photoelectron spectroscopy has been implemented in version 2003 of the spectra treatment and analysis software UNIFIT in order to improve the understanding of the statistical basis and the reliability of the model parameters for photoelectron spectra. The theoretical basis as well as two approaches to obtain error limits of the fit parameters have been considered. Several test spectra have been analysed and discussed. A representative example has been chosen to demonstrate the relevance of the error estimation for practical surface analysis. Suggestions for the minimization of errors in the peak‐fitting procedures are presented. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
156.
An ion-exchange method was used to determine complexation constants for the Ni-oxalate and Ni-carbonate systems in a NaClO4 background electrolyte. The Ni-oxalate data were interpreted in terms of a single Niox(aq) complex having log K
1 values for Ni2+ + ox2– Niox(aq) of 3.9 ± 0.1 (I.S. = 0.5 mol-L–1 p[H] = 7.1) and 4.4 ± 0.1 (I.S. = 0.1 mol-L–1 p[H] = 8.6) at 22 ± 1C. Specific ion-interaction theory (SIT) was used to obtain log K
1
= 5.17 ± 0.05 (95% confidence level and = –0.23 ± 0.15) at I.S. = 0. The Ni-carbonate studies were carried out at p[H] values of 7.5, 8.5, and 9.6 in 0.5 mol-L–1 NaClO4/NaHCO3 solutions. The NiCO3(aq) species was the dominant complex in the [CO3
2–] concentration ranges studied at all three p[H] values. A log K
1 value for Ni2+ + CO3
2– NiCO3(aq) of 2.9 ± 0.3 was deduced at I.S. = 0.5 mol-L–1. Extrapolating this value to zero ionic strength using the SIT approach yielded log K
1
= 4.2 ± 0.3 (95% confidence level and = –0.26 ± 0.04). The data allowed upper bound values for the complexation constants for NiHCO3
+ and Ni(CO3)2
2– to be estimated, i.e., log K
< 1.4 for Ni2+ + HCO3
– NiHCO3
+, and log K
2
< 2 for NiCO3(aq) + CO3
2– Ni(CO3)2
2–, respectively. 相似文献
157.
Summary Gas chromatographic unified retention indices for 43 hydrocarbons (alkanes and cycloalkanes) are given for squalane and OV-101. Comparison of these values and unified retention index increments are presented as linear regression equations with high correlation coefficients and acceptable standard deviations. 相似文献
158.
A. L. Llamas-Saiz Concepción Foces-Foces 《Monatshefte für Chemie / Chemical Monthly》1993,124(3):243-248
A statistical analysis based on crystal structure results of 4-coordinated complexes of Ni, Pd, and Pt containing triphenylphosphine as ligand has been performed using the Cambridge Structural Data Base. Distorted square-planar coordination appears as the most probable one presented by these metals.
Geometrische Charakteristika von vier-koordinierten Komplexen des Ni, Pd und Pt mit Triphenylphosphin als Ligand
Zusammenfassung Es wurde unter Verwendung der Cambridge Strukturdatenbank eine statistische Analyse von Resultaten an vier-koordinierten Komplexen des Ni, Pd und Pt mit Triphenylphosphin-Ligand durchgeführt. Dabei ergab sich eine verzerrte quadratisch-planare Koordination als die am meisten wahrscheinliche Geometrie.相似文献
159.
In environmental chemistry studies, it may be necessary to analyze data sets constituted by different blocks of variables, possibly of different types, measured on the same samples. Multiple factor analysis (MFA) is presented as a tool for exploring such data. The most important features of MFA are shown on a real environmental data set, consisting of two blocks of data, namely heavy metals and polycyclic aromatic hydrocarbons, measured for sediment samples. They are discussed and compared to principal component analysis (PCA). The usefulness of the weighting scheme used in MFA as a preprocessing step for other chemometric methods, such as clustering, is also highlighted. 相似文献
160.
The linearity of the relationship between σT,t2 and (1 + k)2 is studied with the view of using it for the evaluation of GC equipment. Based on appropriate analytical expressions it is concluded that in general this relationship is not linear and that practical procedures for column evaluation should be developed that take this non-linearity into account. 相似文献