Spectroscopy sequential

A TRIAX 550 spectrometer attached to an Andor -90°C cooled CCD detector was used for all spectroscopic measurements. Ar laser lines at 488.0 nm and 514.3 nm were used. Reactions were monitored by time-resolved Raman spectroscopy, sequentially setup for two of three separate regions of interest within the spectral range. This enabled, for example, collecting information about the carboxylation/decarboxylation and hydration/dehydration processes by monitoring the various CO and CH vibration modes. This technique provided spectra in each region only after the collection of the spectra in other regions, and hence not favorable for faster kinetics. However, inclusion of OH and H2 peaks gave a reasonably quantitative estimate on the extent of the hydrothermal reaction and valuable information for mass balance calculations (see further details in the experimental results for each system)... 

Dear, G.J. Ayrton, J. Plumb, R. Sweatman, B.C. Ismail, I. M. Fraser, I.J. Mutch, P.J. A rapid and efficient approach to metahohte identification using nuclear magnetic resonance spectroscopy, liquid chromatography/mass spectrometry and hquid chromatography/nuclear magnetic resonance spectroscopy/sequential mass spectrometry. Rapid Commun. Mass Spectrom. 1998,12, 2023-2030. 

Thus, we implement robust diagnostic methods, which are as un-intmsive as possible, with a view to management of the battery s operation and predictive maintenance of the components during their operation. These methods are based on electrical or empirical models using measurements of the voltage, current and temperature, and monitoring of the electrical parameters which are representative either of the SOC or the SOH. These electrical parameters are obtained from electrochemical measurements taken by impedance spectroscopy (Sequential measurements described in section 2.4.12) or by pulsed current (temporal measurements) such as the internal resistance. Thermal models on the scale of the element or of the pack are also of crucial importance. ... 

The role of acid in the photoreaction was studied using UV-spectroscopy. Sequential addition of TFA (0 to 10 molar equiv.) to a solution of 2a in cyclohexane decreased the UV absorbance at 249 nm (8 = 10400) to 8 = 9960 and increased the 307 nm (e = 1640) to 8 = 1820 with isosbestic points at 242 and 248 nm. Addition of aqueous potassium carbonate (2 molar equiv. to TFA added) returned the spectrum to its original form, suggesting that 2a forms a charge-transfer complex with TFA. The other C-methylcyclooctapyrimidines (2b, e, f) that underwent the rearrangement showed similar spectroscopic behavior. 

In Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), a gaseous, solid (as fine particles), or liquid (as an aerosol) sample is directed into the center of a gaseous plasma. The sample is vaporized, atomized, and partially ionized in the plasma. Atoms and ions are excited and emit light at characteristic wavelengths in the ultraviolet or visible region of the spectrum. The emission line intensities are proportional to the concentration of each element in the sample. A grating spectrometer is used for either simultaneous or sequential multielement analysis. The concentration of each element is determined from measured intensities via calibration with standards. 

Atomic absorption spectroscopy of VPD solutions (VPD-AAS) and instrumental neutron activation analysis (INAA) offer similar detection limits for metallic impurities with silicon substrates. The main advantage of TXRF, compared to VPD-AAS, is its multielement capability AAS is a sequential technique that requires a specific lamp to detect each element. Furthermore, the problem of blank values is of little importance with TXRF because no handling of the analytical solution is involved. On the other hand, adequately sensitive detection of sodium is possible only by using VPD-AAS. INAA is basically a bulk analysis technique, while TXRF is sensitive only to the surface. In addition, TXRF is fast, with an typical analysis time of 1000 s turn-around times for INAA are on the order of weeks. Gallium arsenide surfaces can be analyzed neither by AAS nor by INAA. 

Table 5.9 summarises the main features of FTIR spectroscopy as applied to extracts (separated or not). Since many additives have quite different absorbance profiles FTIR is an excellent tool for recognition. Qualitative identification is relatively straightforward for the different classes of additives. Library searching entails a sequential, point-by-point, statistical correlation analysis of the unknown spectrum with each of the spectra in the library. Fully automated analysis of... 

A study of sequential Arbuzov-type demethylation reactions of the platinum(II)-phosphite complex [Pt P(OMe)3 4]2+, in which the phosphite ligands are converted to phosphonates, has been described.285 Many of the products of the reaction were characterized by NMR spectroscopy and X-ray crystallography.286 The X-ray structures are the first reported for trialkylphosphite complexes of platinum(II). 

An interesting feature of polarized IR spectroscopy is that rapid measurements can be performed while preserving molecular information (in contrast with birefringence) and without the need for a synchrotron source (X-ray diffraction). Time-resolved IRLD studies are almost exclusively realized in transmission because of its compatibility with various types of tensile testing devices. In the simplest implementation, p- and s-polarized spectra are sequentially acquired while the sample is deformed and/or relaxing. The time resolution is generally limited to several seconds per spectrum by the acquisition time of two spectra and by the speed at which the polarizer can be rotated. Siesler et al. have used such a rheo-optical technique to study the dynamics of multiple polymers and copolymers [40]. 

The simplest such type of design is the sequential design, simplest if for no other reason than that the type of design it replaces is one of the simplest designs itself. This design is the simple test for comparison of means, using the Z-test or the t-test as the test statistic we have discussed these in our previous column series and book Statistics in Spectroscopy (now in its second edition [1]). 

The use of short (fs) laser pulses allows even highly transient ion-radical pairs with lifetimes of t 10 12 s to be detected, and their subsequent (dark) decay to products is temporally monitored through the sequential spectral changes. As such, time-resolved (ps) spectroscopy provides the technique of choice for establishing the viability of the electron-transfer paradigm. This photochemical (ET) mechanism has been demonstrated for a variety of donor-acceptor interactions, as presented in the foregoing section. 

The interactions of (212) and related species with monovalent and divalent metal cations have been studied by nmr spectroscopy (Lehn Simon, 1977). The study indicated that sequential formation of mono-and di-cation complexes occurs (see [4.7]). These studies, and especially a 13C nmr study of the 1 1 complex of (212) with barium nitrate, suggest that the 1 1 species are unsymmetrical with the metal ion being contained in one of the azacrown cavities. Nevertheless, the nmr data also indicate that these 1 1 species undergo internal cation exchange between the respective azacrown sites. This intramolecular dynamic behaviour serves... 

The EEM fluorescence spectroscopy involved scanning and recording of 23 individual emission spectra (220-510 nm) at sequential increments of 10 nm of excitation wavelength between 260 and 490 nm. The spectra were recorded at a scan speed of 1000 nm/min using excitation and emission slit bandwidths of 10 nm. Analyses were performed at a constant laboratory temperature of 22 3 °C, and blank water scans were run between every 10-20 analyses using a sealed distilled water cell. 

A combination of direct observation and extraction may be carried out. The whole soil may be analyzed by various methods and then specific components sequentially extracted and measured. This approach has been used in the investigation of the speciation of metals in soil under various conditions. Using X-ray spectroscopy, metals and their various ionic forms in soil can be directly identified [1],... 

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