complicated potential structure formed at a constriction of positive column of a dc discharge with heated cathode in he at low discharge currents is investigated. according to the potential structure, electrons and ions are accelerated by the electric field and their energy distribution functions acquire multi humped shapes. additional maximums on distribution functions quickly disappear due to...

A truly universal nucleobase enables a host of novel applications such as simplified templates for PCR primers, randomized sequencing and DNA based devices. A universal base must pair indiscriminately to each of the canonical bases with little or preferably no destabilization of the overall duplex. In reality, many candidates either destabilize the duplex or do not base pair indiscriminatingly....

a frequency domain dynamic analysis is needed to obtain the response of structures constructed on a system of base isolators on flexible soil when subjected to earthquake ground motion. in such systems, the lateral stiffness of the base isolators is so small, compared to the structural stiffness, that in an earthquake attack the fundamental vibration mode dominates the response. with this in mi...

Many RNA molecules fold into complex secondary and tertiary structures that play critical roles in biological function. Among the best-established methods for examining RNA structure are chemical probing experiments, which can report on local nucleotide structure in a concise and extensible manner. While probing data are highly useful for inferring overall RNA secondary structure, these data do...

in practice, foundations are settled on the soft layers of soil, so the ground must be designed as well as the structure. wave propagation and hysteresis damping of soil layers may alter the seismic response of flexible-base design in comparison to controversial fixed-base. lots of uncertainties about this issue, necessitate most of seismic design standards including iranian standard no. 2800 t...

We consider the unit tangent sphere bundle of Riemannian manifold ( M, g ) with g-natural metric G̃ and we equip it to an almost contact B-metric structure. Considering this structure, we show that there is a direct correlation between the Riemannian curvature tensor of ( M, g ) and local symmetry property of G̃. More precisely, we prove that the flatness of metric g is necessary and sufficien...