Physico-chemical processes in metal-oxide-semiconductor transistors with thick gate oxide during high electric field stress

A complete study of the defects created in the gate oxide and at the gate oxide/substrate interface of metal-oxide-semiconductor transistors with thick gate oxide (t_ox > 10 nm) during high electric field stress, and the mechanisms responsible for these defects creation have been given. In addition, some results of positive/negative high electric field stress with constant gate voltage of commercial n-channel power metal-oxide-semiconductor transistors with thick gate oxide of 100 nm, have been explained using this study.     

Karamata functions and differential equations: Achievements from the 20th century

This paper presents the major achievements of the 20th century regarding Karamata functions and the theory of differential equations, made mostly by V. Mari?, M. Tomi?, E. Omey, J.L. Geluk. The connection between these notions was first noticed by V.G. Avakumovi? (1910–1990). Slowly and regularly varying functions were introduced by J. Karamata (1902–1967). A group of mathematicians from the Karamata School of classical mathematical analysis were pioneers in research on these functions and their role in the theory of differential equations. Special attentions is given to the study of the Thomas–Fermi, Emden–Fowler and Friedmann equations, as well as the classical second order linear differential equations.     

Nonlinear vibration of a nonlocal functionally graded beam on fractional visco-Pasternak foundation

Nonlinear Dynamics - A (3+1)-dimensional coupled nonautonomous NLS model with partially nonlocal coupled nonlinearities under the linear and harmonic potentials becomes the center of attention. Two...     

Mass spectrometric study of some 4-pyrimidine carboxylic acids

Mass spectrometry has been applied in order to study the main fragmentation routes of some 4-pyrimidene carboxylic acids. Differences in fragmentation were caused by the nature of the substituent in position 2 of the pyrimidine ring, while the methyl group in position 1, 3 or 6 did not influence the fragmentation route.     

Effect of lithium salt on the stability of dispersions of fumed silica in the ionic liquid BMImBF4

We have investigated the stability and interactions in dispersions of colloidal fumed silica, Aerosil 200, and the ionic liquid 1-butyl-3-methylimidazolium tetraflouroborate (BMImBF(4)) as a function of the Li salt concentration (LiBF(4)). Photon correlation spectroscopy was used to study the aggregation behavior at low silica concentrations, and Raman spectroscopy was used to investigate the interactions in the ionic liquid and with the silica surface. We find that the addition of LiBF(4) increases the stability of the dispersions, with smaller agglomerates of silica particles and higher gelation concentrations in the presence of Li salt. The increased stability with the addition of Li salt is explained by the formation of a more stable solvation layer, where Li ions accumulate on the surface. This leads to an increased interaction between lithium ions and the BF(4)(-) anions in the solvation layer, as seen by Raman spectroscopy. Upon gelation, the Li ions are expelled from the surface because hydrogen bonding between the silica particles are formed. For both neat BMImBF(4) and Li-salt-doped BMImBF(4)/silica dispersions, a weak gel phase was found preceding the formation of a strong gel at slightly higher silica concentrations.     

Orbital views of molecular conductance perturbed by anchor units

Site-specific electron transport phenomena through benzene and benzenedithiol derivatives are discussed on the basis of a qualitative Hu?ckel molecular orbital analysis for better understanding of the effect of anchoring sulfur atoms. A recent work for the orbital control of electron transport through aromatic hydrocarbons provided an important concept for the design of high-conductance connections of a molecule with anchoring atoms. In this work the origin of the frontier orbitals of benzenedithiol derivatives, the effect of the sulfur atoms on the orbitals and on the electron transport properties, and the applicability of the theoretical concept on aromatic hydrocarbons with the anchoring units are studied. The results demonstrate that the orbital view predictions are applicable to molecules perturbed by the anchoring units. The electron transport properties of benzene are found to be qualitatively consistent with those of benzenedithiol with respect to the site dependence. To verify the result of the Hu?ckel molecular orbital calculations, fragment molecular orbital analyses with the extended Hu?ckel molecular orbital theory and electron transport calculations with density functional theory are performed. Calculated results are in good agreement with the orbital interaction analysis. The phase, amplitude, and spatial distribution of the frontier orbitals play an essential role in the design of the electron transport properties through aromatic hydrocarbons.