No abstract available

No abstract available

[en] Shack-Hartmann Wave-front Sensor is a popular instrument used to measure wavefront. And micro-lens array is the important component of it. In this paper we compared the reconstruction precision of square configuration sub-aperture with that of hexagon configuration through simulation. The result shows that the main factors influence the reconstruction precision is the layout of edge sub-apertures in both configurations. When the two figurations have the similar value area ratio of edge sub-apertures, hexagon configuration has higher reconstruction precision

No abstract available

[en] Published in summary form only

[en] The ground state behavior of two-dimensional symmetrical mixtures subjected to the external potential of square symmetry is discussed. It is demonstrated that different commensurate, high-order commensurate as well as incommensurate phases may appear depending on the properties of the mixture as well as on the corrugation of external potential. In particular, it is shown that a finite corrugation of external potential considerably influences the stability of different ordered states. The ground state calculations are confirmed by finite temperature grand canonical Monte Carlo simulations. (authors)

No abstract available

[en] Square hierarchical lattices are two-dimensional self-similar space-filling lattices which lack translational symmetry. In this paper, we report our study of the anomalous diffusion and lattice vibration properties of two distinct square hierarchical lattices

[en] Local heat/mass transfer and friction loss in a square duct roughened with various types of continuous and discrete rib turbulators are investigated. The combined effects of the gap flows of the discrete ribs and the secondary flows are examined for the purpose of the reduction of thermally weak regions and the promotion of the uniformity of heat/mass transfer distributions as well as the augmentation of average heat/mass transfer. The rib-to-rib pitch to the rib height ratio (p/e) of 8 and the rib angles of 90 .deg. and 60 .deg. are selected with e/D_h=0.008. The vortical structure of the secondary flows induced by the parallel angled arrays are quite distinct from that induced by the cross angled arrays. This distinction influences on heat/mass transfer and friction loss in all the tested cases. The gap flows of the discrete ribs reduce the strength of the secondary flows but promote local turbulence and flow mixing. Consequently, the angled discrete ribs with the small gaps provide a more uniform heat/mass transfer distribution high average heat/mass transfer

[en] We prove the existence of a highly symmetric family of central configurations in which 16 non-negative masses move in concentric circular motions in $p=3$ rings of radii $a_1,a_2,a_3$. On the first ring, there are four bodies of equal masses in a square configuration. On the second ring there are also four bodies of equal masses, each of which located on the bisectors of the angles formed by each pair of the position vectors of two consecutive bodies of the first ring. On the third ring, there are eight bodies of equal masses, each of which is located on the bisectors of the angles formed by each pair of position vectors of two consecutive bodies of the previous two rings. We study the inverse problem, i.e., given three positive radii $a_1,a_2,a_3$ we determine the values of the corresponding non-negative masses $m_1$, $m_2$ and $m_3$, for which the above described configuration is central. We present some particular interesting cases and study some geometrical features of such configurations. We end this paper proposing several lines of possible further generalizations.