On the basis of 102 assigned frequencies to in plane vibrations of pyrimidine, pyrimidine-2-d2, pyrimidine-2, 5-d2, pyrimidine-4,6-d2, pyrimidine-2,4,6-d3 and pyrimidine-d4, 35 valance force field constants including 14 principals and 21 interaction force constants are calculated. New assignments are suggested for n<su...

This paper presents the stability analysis of a single degree of freedom elastic system following a rateand state-dependent friction law. Normal force is assumed to depend on the displacement, velocity and acceleration of the sliding interface. The history dependence of friction on normal force is included in the analysis. It is shown that to achieve steady sliding, system sti ness must exceed ...

Objectives: Foot and ankle problems are common complications in rheumatoid arthritis disease. Gait pattern such as normal foot and ankle rocker is impaired in patients with rheumatoid arthritis. Rocker sole as an external shoe modification is commonly prescribed in this pathology. The aim of this study was to investigate the effect of rocker shoe on vertical ground reaction force parameters dur...

This article proposes a technique to calculate the coefficient of friction for the fingertip- object interface. Twelve subjects (6 males and 6 females) participated in two experiments. During the first experiment (the imposed displacement method), a 3-D force sensor was moved horizontally while the subjects applied a specified normal force (4 N, 8 N, 12 N) on the surface of a sensor covered wit...

The conditions that limit the possible excitation of ideal MHD axisymmet-ric ballooning modes in thin accretion disks are discussed. As shown earlier by Coppi & Coppi (2001a), these modes are well-localized in the vertical direction but have characteristic oscillatory and non-localized profiles in the radial direction. A necessary condition for their excitation is that the magnetic energy be co...

We have refined vibrational force fields for polypeptides that permit excellent reproduction of the normal mode frequencies of such molecules. This is demonstrated in the present study, in which 80 IR and Raman bands of crystalline triglycine between 1800 and 200 cm-’ are reproduced with an average error of 6 cm-‘. A deuterated sample is shown by normal mode analysis to have remained protonated...

We use dynamical low-energy electron diffraction ~LEED! to determine the surface structure of a-Al2O3(0001). Sapphire surfaces are prepared in three different ways, and the diffraction results are analyzed using an exhaustive search of possible models. For all sample processing conditions, the clearly favored structure has a single Al layer termination and a large first interlayer contraction. ...

Vibrational energy transfer of the amide I mode of N-methylacetamide (NMA) is studied theoretically using the vibrational configuration interaction method. A quartic force field of NMA is constructed at the B3LYP/6-31G+(d) level of theory and its accuracy is checked by comparing the resulting anharmonic frequencies with available theoretical and experimental values. Quantum dynamics calculation...