Classification of intelligence quotient via brainwave sub-band power ratio features and artificial neural network.

This paper elaborates on the novel intelligence assessment method using the brainwave sub-band power ratio features. The study focuses only on the left hemisphere brainwave in its relaxed state. Distinct intelligence quotient groups have been established earlier from the score of the Raven Progressive Matrices. Sub-band power ratios are calculated from energy spectral density of theta, alpha and beta frequency bands. Synthetic data have been generated to increase dataset from 50 to 120. The features are used as input to the artificial neural network. Subsequently, the brain behaviour model has been developed using an artificial neural network that is trained with optimized learning rate, momentum constant and hidden nodes. Findings indicate that the distinct intelligence quotient groups can be classified from the brainwave sub-band power ratios with 100% training and 88.89% testing accuracies.

The critical evaluation of a comprehensive mass spectral library.

A description of the methods used to build a high quality, comprehensive reference library of electron-ionization mass spectra is presented. Emphasis is placed on the most challenging part of this project--the improvement of quality by expert evaluation. The methods employed for this task were developed over the course of a spectrum-by-spectrum review of a library containing well over 100,000 spectra. Although the effectiveness of this quality improvement task depended critically on the expertise of the evaluators, a number of guidelines are discussed which were found to be effective in performing this onerous and often subjective task. A number of specific examples of the particularly challenging task of spectrum editing are given.

Comparative evaluations of mass spectral databases.

This Communication presents a statistical analysis of the distributions of the National Institute of Standards and Technology/Environmental Protection Agencyj Mass Spectrometry Data Center Mass Spectral Database and the Wiley Registry of Mass Spectra according to sizes (peaks per spectrum) of spectra. The differences in the distributions are explained in terms of the different philosophies under which the two databases were built. The Wiley Registry is a collection that attempts to include all available spectra, including spectra of unique compounds derived from the literature. The NIST collection selects primarily spectra of interest for chemical analysis.

Pulse Radiolysis of Methane.

The pulse radiolysis of methane has been studied in the absence and presence of electron scavengers such as SF6 and CD3I and positive ion scavengers such as i-C4D10 in order to define the role of the intermediates H, C, CH, CH2, CH3, CH 5 + , and C 2 H 5 + in product formation. The dose rate was varied from 0.68 to 15.2 × 1019 eV/g-s, the dose (number of pulses) was varied, and the duration of the pulse was changed from 3 ns to 100 ns. The variation of the yields of the ethylene and ethane products with dose is explained by the reaction of H-atoms with accumulated ethylene product. The fast reacting C, CH, and 1CH2 species insert into methane to form acetylene, ethylene, and ethane products, but all of the reactions of these species cannot be completely specified since they may originate in upper electronic states, whose reactions with methane are unknown. Product formation by the slow reacting 3CH2 and CH3 radicals is also examined; for instance, evidence is presented for the occurrence of the reaction: 3CH2 + CH3 → C2H4 + H. Results indicate that the ions CH 5 + and C 2 H 5 + undergo neutralization mainly through the processes CH 5 + + e → CH 4 + H C 2 H 5 + + e → ( C 2 H 4 ) * + H → C 2 H 2 + H + H 2 ( 2 H ) When i-C4D10 is added, a fraction of the CH 5 + and C 2 H 5 + react with the additive rather than undergo neutralization. A calculation demonstrates that the fraction of ions undergoing reaction with a given concentration of i-C4D10 can be correctly predicted by assuming that the rate constant for neutralization of CH 5 + and C 2 H 5 + is the same as that determined recently for the t-butyl ion.

Photoionization of C 4 H 8 + Isomers. Unimolecular and Bimolecular Reactions of the C 4 H 8 + Ions.

1-Butene, cis-2-butene, isobutene and methylcyclopropane have been photoionized with the resonance lines of krypton (10.0-10.6 eV) and argon (11.6-11.8 eV). We have determined that the internally excited 1 - C 4 H 8 + ion and, to a much lesser extent, the i - C 4 H 8 + ion isomerizes to the 2 - C 4 H 8 + structure. In both cases the extent of isomerization increases, approximately by a factor of ten when the photon energy is increased from 10 to 11.7 eV. An inert gas, neon, quenches the isomerization of the i - C 4 H 8 + ion and, to a much lesser rextent, that of the 1 - C 4 H 8 + ion. The unimolecular fragmentation of the C 4 H 8 + isomeric ions has been examined at 11.61-11.8 eV. In this energy range the dissociative lifetime of i - C 4 H 8 + was found to be at least 5 × 10-6 s, and collisional quenching of the dissociative process is already noticeable at pressures in the 10-3 torr range. The rate coefficients for the reaction C 4 H 8 + (  thermal  ) + C 4 H 8 → ( C 8 H 16 + ) * occurring in the isomeric C4H8 systems have been determined under conditions where the structure of the reacting C 4 H 8 + ion is established. The values in cm3/molecule · second are 1-C4H8 - 6.0 ± 0.5 × 10-l0, cis-2-C4H8 - 0.37 ± 0.1 × 10-10, i-C4H8 - 5.4 ± 0.4 × 10-10. At pressure below 10-3 torr, the internally excited ( C 8 H 16 + ) * produced in the reaction dissociates along various channels with relative probabilities depending upon the structure of both the ionic and neutral reactant. Above 10-3 torr collisional quenching of ( C 8 H 16 + ) * is noted.

The Photochemistry of Propane at High Photon Energies (8.4-21.2 eV).

Neon and helium resonance lamps, which deliver photons of 16.7-16.8 eV and 21.2 eV energy, respectively, have been used to photolyze C3H8, C3D8, C3H8-C3D8 (1:1) mixtures, and the results obtained at the two energies are compared. In particular, it is noted that although the quantum yield of ionization in propane is unity at 16.7-16.8 eV, when the energy is raised still further to 21.2 eV, the probability of ionization apparently diminishes to 0.93, an observation which suggests that at 21.2 eV, superexcited states may be reached whose dissociation into neutral fragments competes with ionization. The quantum yields of the lower hydrocarbon products formed in the presence of a radical scavenger in C3H8 and C3D8 are reported, and are compared with quantum yields of products formed in the vacuum ultraviolet photolysis at lower energies. (Quantum yields of products formed at 8.4 eV and 10.0 eV are reported here for the first time.) Acetylene is formed as a product in the decomposition of the neutral excited propane molecule, and its yield increases in importance with increasing energy; at 16.7-16.8 eV, where all product formation can be traced to ionic processes, acetylene is formed in negligible yields. It is concluded that ionic processes in propane do not lead to the formation of acetylene, and the observation of this product in radiolytic systems may be a reliable indicator of the relative importance of neutral excited molecule decomposition processes. From the results obtained with the C3H8-C3D8 (1:1) mixture, and with CD3CH2CD3, details of the ion-molecule reaction mechanisms and the unimolecular decomposition of the propane ion are derived.

Isomerization Processes in Ions of the Empirical Formula C 4 H 8 + .

Ions of the formula C 4 H 8 + have been generated with different initial energies by ionizing ethylene ( C 2 H 4 + + C 2 H 4 → C 4 H 8 + , where the C 4 H 8 + ion is formed with an initial energy of > 11.51 eV), cyclobutane (initial energy of C 4 H 8 + , > 10.84 eV), methylcyclopropane (> 10.15 eV), 1-C4H8 (> 9.58 eV), and i-C4H8 (> 9.06 eV) with 11.6-11.8 eV photons, and in some cases also with 10 eV photons and with gamma radiation. The structures of the ions have been determined from the structures of the C4H8 products formed in charge transfer reaction between the ions and charge acceptors such as dimethylamine and nitric oxide, as well as from the structures of the butanes formed in D 2 - transfer reactions with methylcyclopentane-d 12 ( C 4 H 8 + + C 6 D 12 → C 4 H 8 D 2 + C 6 D 10 + ). At low pressures the C 4 H 8 + ions initially formed in ethylene, cyclobutane, and methylcyclopropane isomerize to the thermodynamically most stable configurations, i-C 4 H 8 + and 2-C 4 H 8 + . The 2-C 4 H 8 + structure predominates in all the experiments. As the pressure is raised, the i-C 4 H 8 + ion yield diminishes as that of 2-C 4 H 8 + increases, indicating that when the precursor of the i-C 4 H 8 + ion is collisionally deactivated, it ends up as 2-C 4 H 8 + . At high pressures, 1-C 4 H 8 + ions are intercepted; their yield increases with increasing pressure, indicating that 1-C 4 H 8 + is an intermediate which isomerizes further unless it is collisionally deactivated. The 1-C 4 H 8 + ion formed in methylcyclopropane (initial energy > 10.15 eV) is more easily deactivated than that formed in cyclobutane (initial energy > 10.84 eV). That the isomerization of the 1-C 4 H 8 + ion to lower energy structures such as i-C 4 H 8 + and 2-C 4 H 8 + requires excess internal energy is demonstrated by the fact that in the photolysis with 10 eV photons, a negligible amount of isomerization is observed, but with 11.6-11.8 eV photons, more than half of the 1-C 4 H 8 + ions isomerize to the 2-C 4 H 8 + structure at a pressure of 2 torr. Isomerization of the low energy i-C 4 H 8 + ions formed in the photolysis of i-C4H8 to other structures is relatively unimportant at 11.6-11.8 eV. Taking the ratio i-C 4 H 8 + / 2 -C 4 H 8 + as an indicator of the amount of energy removed by collisions from the intermediate C 4 H 8 + species under conditions where only i- and 2 -C 4 H 8 + ions are intercepted, it is shown that the efficiency of energy transfer from the ions to helium, hydrogen, neon, krypton, xenon, nitrogen, and carbon dioxide is related to the polarizability of the added deactivator.