34,654 research outputs found
Experimental investigation on thermal comfort model between local thermal sensation and overall thermal sensation
To study the human local and overall thermal sensations, a series of experiments under various conditions were carried out in a climate control chamber. The adopted analysis method considered the effect of the weight coefficient of local average skin temperature and density of the cold receptors’ distribution in different local body areas. The results demonstrated that the thermal sensation of head, chest, back and hands is warmer than overall thermal sensation. The mean thermal sensation votes of those local areas were more densely distributed. In addition, the thermal sensation of arms, tight and calf was colder than the overall thermal sensation, which pronounced that thermal sensation votes were more dispersed. The thermal sensation of chest and back had a strong linear correlation with overall thermal sensation. Considering the actual scope of air-conditioning regulation, the human body was classified into three local parts: a) head, b) upper part of body and c) lower part of body. The prediction model of both the three-part thermal sensation and overall thermal sensation was developed. Weight coefficients were 0.21, 0.60 and 0.19 respectively. The model provides scientist basis for guiding the sage installation place of the personal ventilation system to achieve efficient energy use
Bond distortion effects and electric orders in spiral multiferroic magnets
We study in this paper bond distortion effect on electric polarization in
spiral multiferroic magnets based on cluster and chain models. The bond
distortion break inversion symmetry and modify the - hybridization.
Consequently, it will affect electric polarization which can be divided into
spin-current part and lattice-mediated part. The spin-current polarization can
be written in terms of and
the lattice-mediated polarization exists only when the M-O-M bond is distorted.
The electric polarization for three-atom M-O-M and four-atom M-O-M
clusters is calculated. We also study possible electric ordering in three kinds
of chains made of different clusters. We apply our theory to multiferroics
cuprates and find that the results are in agreement with experimental
observations.Comment: 14 pages, 11 figure
Top Quark Forward-Backward Asymmetry and Same-Sign Top Quark Pairs
The top quark forward-backward asymmetry measured at the Tevatron collider
shows a large deviation from standard model expectations. Among possible
interpretations, a non-universal model is of particular interest as
it naturally predicts a top quark in the forward region of large rapidity. To
reproduce the size of the asymmetry, the couplings of the to
standard model quarks must be large, inevitably leading to copious production
of same-sign top quark pairs at the energies of the Large Hadron Collider
(LHC). We explore the discovery potential for and production in
early LHC experiments at 7-8 TeV and conclude that if {\it no} signal is
observed with 1 fb of integrated luminosity, then a non-universal
alone cannot explain the Tevatron forward-backward asymmetry.Comment: Tevatron limit from same-sign tt search adde
Comment on "Single-mode excited entangled coherent states"
In Xu and Kuang (\textit{J. Phys. A: Math. Gen.} 39 (2006) L191), the authors
claim that, for single-mode excited entangled coherent states , \textquotedblleft the photon excitations lead to the
decrease of the concurrence in the strong field regime of and
the concurrence tends to zero when ". This is wrong.Comment: 4 apges, 2 figures, submitted to JPA 15 April 200
WHAT ARE VALUES OF SHOELACES IN RUNNING?
Shoelaces are widely thought to make running shoes more comfortable and well-fitted. Studies on the effects of lacing patterns of running shoes on plantar pressure distribution, shock attenuation, and rearfoot motion found that shoe lacing patterns had a remarkable influence on foot-shoe coupling in running (Hagen & Henning, 2008). Their results showed that tighter shoelaces or lacing these closer to the ankle joint resulted in better use of running shoe features. Recently, a type of no-lace running shoes, in which an elastic material is used to replace the traditional lace structure, has been designed by a shoe company. However, there is no available information on the effects of shoes with or without lace structures on foot biomechanics during running. As such, the purpose of this study was to examine if there were differences between running shoes with and without the lace system on perceived comfort, plantar pressure distribution, and rearfoot motion control in running
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