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Rensheng Deng Davis Yohanes Arifin Mak Ye Chyn Chi-Hwa Wang 《Chemical engineering science》2010,65(16):4598-4605
We present a study on Taylor vortex flow in between a rotating inner cylinder and a stationary outer cylinder with vertical or horizontal baffles. A mineral oil is used as the working fluid in the annular channel of 60 mm in height and 11.6 mm in gap width. The flow pattern in the annulus is investigated by particle image velocimetry (PIV) and computational fluid dynamics (CFD). Both the experimental and simulation results show that the presence of vertical baffles influences the vertical positions of vortices—it is primarily significant for the bottom vortex. Increasing number of vertical baffles gradually decreases the azimuthal variation in the vertical position. The baffles also lead to the occurrence of a circulation flow immediately upstream and downstream each baffle plate in the radial–azimuthal plane. On the other hand, an annular horizontal baffle with sufficient width alters the vortex structure in the gap, for instance, fewer vortices are observed. With two horizontal baffles in the annulus, the flow pattern is largely affected by the baffle width and the distance between the two baffles. This study provides a better understanding of Taylor vortex in presence of internal baffles, which will be important for practical applications of Taylor vortex devices. 相似文献
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Test consideration for nanometer-scale CMOS circuits 总被引:1,自引:0,他引:1
The exponential increase in leakage, the device parameter variations, and the aggressive power management techniques will severely impact IC testing methods. Test technology faces new challenges as faults with increasingly complex behavior become predominant. Design approaches aimed at fixing some of the undesirable effects of nanometric technologies could jeopardize current test approaches. In this article, we explore test considerations for scaled CMOS circuits in the nanometer regime and describe possible solutions to many of these challenges, including statistical timing and delay test, I/sub DDQ/ test under exponentially increasing leakage, and power or thermal management architectures. 相似文献
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The binding of the calcium-regulatory protein calmodulin (CaM) to caldesmon (CaD) contributes to the regulation of smooth muscle contraction. Two regions of caldesmon have been identified as putative calmodulin-binding domains. We have earlier reported on the binding of one of these domains to calmodulin (Zhang & Vogel (1994) Biochemistry 33, 1163-1171). Here we have studied the binding of CaM to synthetic peptides of CaD which contain: (1) both the first and second CaM-binding domains; (2) the second CaM-binding domain; and (3) the sequence between the first and second CaM-binding domains. Two-dimensional transferred nuclear Overhauser enhancement proton NMR measurements as well as circular dichroism studies of a 22-residue peptide NKETAGLKVGVSSRINEWLTK, which contains the second CaM-binding domain, show that only the C-terminal half of the peptide becomes alpha-helical upon binding to CaM. Somewhat surprisingly, the shorter 9-residue peptide SRINEWLTK was sufficient to form a 1:1 complex with CaM; this peptide appears to bind as a 3(10)-helix. Proton-carbon-13 correlation NMR titration studies with specifically labeled [methyl-13C]methionine CaM were used to study the participation of the hydrophobic regions in both domains of the dumbbell shaped CaM in peptide binding. Binding of a 54-residue CaD peptide containing both CaM-binding domains affects all the 8 Met residues in the two hydrophobic domains of CaM (only Met 76 in the linker region of CaM is not involved), while binding of the second CaM-binding domain of CaD influences principally Met 51, 71, and Met 124, 144. Simultaneous binding to CaM of two peptides comprising the first and the second CaM-binding domains also caused changes to all Met residues except Met 76. Taken together, these data demonstrate that both CaM-binding domains of CaD can bind simultaneously to the two hydrophobic regions of CaM. 相似文献
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The AA. investigated the frequency of antibodies against Toxoplasma gondii in 426 women with repeated abortions, perinatal mortality and malformed newborns. They showed on the whole a low incidence even if they demonstrated a high incidence (77.7%) of antibodies in women with malformed newborns. The meaning of the observations are briefly discussed. 相似文献