14 research outputs found
An analysis of factors affecting the market price of electricity: the case of Phelix index
The addition reaction of potassium
atoms with oxygen has been studied
using the collinear photofragmentation and atomic absorption spectroscopy
(CPFAAS) method. KCl vapor was photolyzed with 266 nm pulses and the
absorbance by K atoms at 766.5 nm was measured at various delay times
with a narrow line width diode laser. Experiments were carried out
with O<sub>2</sub>/N<sub>2</sub> mixtures at a total pressure of 1
bar, over 748–1323 K. At the lower temperatures single exponential
decays of [K] yielded the third-order rate constant for addition, <i>k</i><sub>R1</sub>, whereas at higher temperatures equilibration
was observed in the form of double exponential decays of [K], which
yielded both <i>k</i><sub>R1</sub> and the equilibrium constant
for KO<sub>2</sub> formation. <i>k</i><sub>R1</sub> can
be summarized as 1.07 × 10<sup>–30</sup>(<i>T</i>/1000 K)<sup>−0.733</sup> cm<sup>6</sup> molecule<sup>–2</sup> s<sup>–1</sup>. Combination with literature values leads
to a recommended <i>k</i><sub>R1</sub> of 5.5 × 10<sup>–26</sup><i>T</i><sup>–1.55</sup> expÂ(−10/<i>T</i>) cm<sup>6</sup> molecule<sup>–2</sup> s<sup>–1</sup> over 250–1320 K, with an error limit of a factor of 1.5.
A van’t Hoff analysis constrained to fit the computed Δ<i>S</i><sub>298</sub> yields a K–O<sub>2</sub> bond dissociation
enthalpy of 184.2 ± 4.0 kJ mol<sup>–1</sup> at 298 K and
Δ<sub>f</sub><i>H</i><sub>298</sub>(KO<sub>2</sub>) = −95.2 ± 4.1 kJ mol<sup>–1</sup>. The corresponding <i>D</i><sub>0</sub> is 181.5 ± 4.0 kJ mol<sup>–1</sup>. This value compares well with a CCSDÂ(T) extrapolation to the complete
basis set limit, with all electrons correlated, of 177.9 kJ mol<sup>–1</sup>
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Proteomics-Based Methods for Discovery, Quantification, and Validation of Protein–Protein Interactions
Proteins play a fundamental role in establishing the diversity of cellular processes in health or disease systems. This diversity is accomplished by a vast array of protein functions. In fact, a protein rarely has a single function. The majority of proteins are involved in numerous cellular processes, and these multiple functions are made possible by interactions with other molecules. The complexity of interactions is substantially increased by the spatial and temporal diversity of proteins. For example, proteins can be part of distinct complexes within different subcellular compartments or at different stages of the cell cycle. Post-translational modifications can regulate and further expand the ability of proteins to establish localization- or temporal-dependent interactions. This complexity and functional divergence of interactions is further increased by the simultaneous presence of stable, transient, direct, and indirect protein interactions. Thus, an understanding of protein functions cannot be fully accomplished without knowledge of its interactions. Characterizing these interactions is therefore critical to understanding the biology of health and disease systems