Spectral analysis time-independent

Time-Independent Quantum-Mechanical Spectral Analysis 154... 

TIME-INDEPENDENT QUANTUM-MECHANICAL SPECTRAL ANALYSIS... 

Time-pulse measurements and spectral analysis revealed a position-independent, periodic process, whose frequency was much lower than that of the paddle movement, but which was linearly dependent upon the stirrer speed. The appearance of macro-instabilities in the proximity of the stirrer coincided with a strong increase in fluctuation intensity at Re w 600. 

Qualitative Analysis. The retention time of a pure compound is constant under a specified set of experimental conditions, including the column, temperature, and flowrate. Consequently, this property may be used as a first step to identify an unknown compound or the individual components in a mixture. In a typical experiment, an unknown compound or mixture is injected into the injection port of a GLC, and the retention time(s) of the component(s) is (are) measiued. A series of known samples are then injected under the same conditions. Comparison of the retention times of the standard samples with those of the unknown allows a preliminary identification of the component(s) of the unknown. A convenient way of confirming that the retention times of a standard and the unknown are the same involves injecting a sample prepared by combining equal amounts of the two. If a single peak is observed in the chromatogram, the retention times of the standard and the unknown are identical. However, observation of the same retention time for a known and an unknown substance is a necessary but not sufficient condition to establish identity, because it is possible for two different compounds to have the same retention time. Independent confirmation of the identity of the unknown by spectral (Chap. 8) or other means is imperative. 

One of the earliest applications of the Kalman filter in analytical chemistry was multicomponent analysis by UV-Vis spectrometry of time and wavelength independent concentrations, which was discussed by several authors [7-10]. Initially, the spectral range was scanned in the upward and downward mode, but later on... 

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