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81.
Static and dynamic hydrophobicities of water droplet on a patterned surface prepared using fluoroalkylsilanes with different molecular chain lengths were investigated. Contact angles on the patterned surfaces well agreed with values predicted using Cassie’s theory. On the same line width ratio, total retention force was governed by the fluoroalkylsilane with slow-sliding acceleration. The total retention force decreased with the decreasing width ratio of silane with slow-sliding acceleration on the surface. These results imply that the sliding acceleration of water droplets on a hydrophobic surface depends both on chemical composition and patterning structure. 相似文献
82.
Olson Reichhardt CJ Reichhardt C Bishop AR 《The European physical journal. E, Soft matter》2007,22(1):11-15
Motivated by recent experiments on colloidal systems with
competing attractive and repulsive interactions,
we simulate a two-dimensional system of colloids
with competing interactions that can undergo fragmentation.
In the absence of any
other confining potential, the colloids can form stable clusters
depending on the strength of the short range attractive term.
By suddenly changing the strength of one of the interaction
terms we
find a rich variety of fragmentation behavior which is affected
by the existence of “magic” cluster numbers.
Such soft matter systems can
be used to construct artificial nuclei. 相似文献
83.
84.
Dmitry A. Bratsun Alexej V. Zyuzgin Gennady F. Putin 《International Journal of Heat and Fluid Flow》2003,24(6):835-852
We study both experimentally and numerically the convective flow in a tall vertical slot with differently heated walls. The flow is investigated for the fluid with the Prandtl number Pr=26, which is large enough to ensure the traveling waves as primary instability and small enough to prevent boundary layer convection. The flow evolution is determined on the base of the visual observations, power spectra and amplitude analysis. In the numerical simulations of two- and three-dimensional flows, we accept an assumption of an infinite fluid layer. The satisfactory agreement with experiment is observed, and the sequence of convection states is discovered. It starts with a plane-parallel flow as primary solution, which becomes unstable to two counter-propagating waves. It is followed by a tertiary three-dimensional flow in the form of wavy traveling waves. As the Grashof number is increased even further, a chaotically oscillating cellular pattern consisting of the pieces of broken waves arises. The formation of a structure in the form of the vertical rolls chaotically modulated along axes concludes this complicated picture. 相似文献
85.
86.
Alexander Burstein 《Journal of Combinatorial Theory, Series A》2011,118(8):2346-2364
We give a recursive formula for the Möbius function of an interval [σ,π] in the poset of permutations ordered by pattern containment in the case where π is a decomposable permutation, that is, consists of two blocks where the first one contains all the letters 1,2,…,k for some k. This leads to many special cases of more explicit formulas. It also gives rise to a computationally efficient formula for the Möbius function in the case where σ and π are separable permutations. A permutation is separable if it can be generated from the permutation 1 by successive sums and skew sums or, equivalently, if it avoids the patterns 2413 and 3142.We also show that the Möbius function in the poset of separable permutations admits a combinatorial interpretation in terms of normal embeddings among permutations. A consequence of this interpretation is that the Möbius function of an interval [σ,π] of separable permutations is bounded by the number of occurrences of σ as a pattern in π. Another consequence is that for any separable permutation π the Möbius function of (1,π) is either 0, 1 or −1. 相似文献
87.
88.
We generalize Axel Thue’s familiar definition of overlaps in words, and observe that there are no infinite words avoiding split occurrences of these generalized overlaps. We give estimates for the length of the longest finite word that avoids split overlaps. Along the way we prove a useful theorem about repeated disjoint occurrences in words — an interesting natural variation on the classical de Bruijn sequences. 相似文献
89.
Yoshihiro Fukumoto Koji Ohata Rui Tsukagoshi Keiich Kawanabe Haruhiko Akiyama Toshihiro Mata Misaka Kimura Noriaki Ichihashi 《Physical Therapy Research》2013,16(1):22-27
Objective: To investigate changes in hip and knee muscle strength in patients before and after total hip arthroplasty (THA) in comparison with that in healthy adults. Methods: The study included 21 women who underwent unilateral THA (THA group) and 21 age-matched healthy women (healthy group). Maximal isometric strengths of hip flexors, extensors, and abductors, and knee extensors and flexors were measured before surgery and at 4 weeks and 6 months after surgery. Results: Before surgery, muscle strength on both sides, except for hip flexors on the uninvolved side, was significantly lower in the THA group than the corresponding muscle strength in the healthy group. Up to 6 months after THA, strength of all muscle groups on both sides was significantly improved compared with their preoperative status, although the knee extensor strength on the involved side temporarily worsened at 4 weeks. However, the strength of hip extensors and knee extensors on the involved side, and hip abductors on both sides in the THA group remained below that in the healthy group. Conclusions: Our results suggest that rehabilitation specialists should consider increasing the focus on the uninvolved side and encourage patients to continue strength training beyond 6 months after surgery. 相似文献
90.
X. Zhang G. Hu 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(3):389-393
In this work, we introduce a spatiotemporal modulation for
excitability into an excitable medium, the Barkley model. The
modulation can make the spiral wave tip meandering. Various types of
periodic spiral and quasiperiodic meandering spiral motions can be
observed numerically by varying the modulation. And the theoretical
analysis for the conditions of Hopf bifurcation, based on an
ordinary-differential-equation (ODE) model, is applied to well
explain the rich behaviors of numerical simulations. 相似文献