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951.
Abstract The aging of dielectric, elastic and piezoelectric properties is caused by a reduction of the 90° domain wall mobility. Defect dipoles in the domains orient slowly in energetically preferred directions. The oriented defects increase the force constant for the reversible domain wall displacement by electric or elastic fields. Observations of fatigue in bulk materials are briefly discussed. 相似文献
952.
U. Shumlak J. M. Blakely B.-J. Chan R. P. Golingo S. D. Knecht B. A. Nelson R. J. Oberto M. R. Sybouts G. V. Vogman D. J. Den Hartog 《Journal of Fusion Energy》2009,28(2):208-211
The ZaP flow Z-pinch experiment at the University of Washington investigates the innovative plasma confinement concept of
using sheared flows to stabilize an otherwise unstable configuration. The ZaP experiment generates an axially flowing Z-pinch
that is 1 m long with a 1 cm radius with a coaxial accelerator coupled to a pinch assembly chamber. Magnetic probes measure
the fluctuation levels of the azimuthal modes m = 1, 2, and 3. After assembly, the plasma is magnetically confined for an extended quiescent period where the mode activity
is significantly reduced. Experimental measurements show a sheared flow profile that is coincident with the low magnetic fluctuations
during the quiescent period. Recent experimental modifications produce more energetic Z-pinch plasmas that exhibit the same
general behavior. The plasma equilibrium is characterized with a suite of diagnostics that measure the plasma density, magnetic
field, ion and electron temperatures, in addition to plasma flow. The equilibrium is shown to satisfy radial force balance. 相似文献
953.
S. U. Rahman 《Theoretical Foundations of Chemical Engineering》2012,46(2):108-112
The mass transfer coefficients from the outer surface of tubes or cylinders held in parallel turbulent steams have been calculated
using integral momentum and mass transfer equations. The solution uses a hydrodynamics independent constant, λ
c
which depends only upon Schmidt number. The results exhibit significant effect of curvature. For Schmidt number less than
108, Sherwood number can be predicted by $Sh_d Sc^{ - 1/3} = 0.039Sc^{0.208} \times \left( {\frac{L}
{d}} \right)^\alpha \operatorname{Re} _d^{0.8}$Sh_d Sc^{ - 1/3} = 0.039Sc^{0.208} \times \left( {\frac{L}
{d}} \right)^\alpha \operatorname{Re} _d^{0.8}, where α = −0.169Sc−0.0103. The effect of the curvature is insignificant where $\frac{L}
{d}\operatorname{Re} _L^{ - 0.2} - 0.033 \times \ln (Sc) \leqslant 0.214$\frac{L}
{d}\operatorname{Re} _L^{ - 0.2} - 0.033 \times \ln (Sc) \leqslant 0.214. 相似文献
954.
Leonardo A. de Andrade Matheus R. U. Zingarelli Rodolfo R. Silva Rudinei Goularte 《Multimedia Tools and Applications》2014,71(3):1673-1697
This paper presents a new spatial compression method specifically designed for stereo videos. Different form current compressors, which simply apply known 2D compression techniques, the method proposed here was developed taking into account specificities of the components of the spatial compression process which may impact the correct depth visualization, named Chrominance Subsampling, Discrete WaveletTransform (DWT) and Quantization. Each component was evaluated analyzing where datalosses occur and proposing ways to provide a good balance between compression ratio and image quality, minimizing losses in depth perception. The evaluations were made using standard objective (PSNR) and subjective (DSCQS) metrics, applied to an anaglyphic stereoscopic video base. The results showedour method is competitive regarding compression rate and providessuperior image quality. 相似文献
955.
Using the modified non-linearity approach and the recently introduced Fourier superseries, expressions are derived for the harmonic gains of non-linearities with harmonically related inputs. It is also shown that the extension of the problem to the situation where the commensurate sinusoids are contaminated by noise is straightforward. Examples are given to illustrate the computational procedure. 相似文献
956.
P.P. Hankare M.R. Kadam P.D. Kamble S.D. Jadhav U.B. Sankpal R.P. Patil V.B. Helavi N.S. Gajbhiye 《Journal of Alloys and Compounds》2010,489(1):233-236
The system manganese substituted lanthanum ferrite viz. LaMnxFe1?xO3 (1.0 ≤ x ≥ 0) was prepared by sol–gel autocombusion method. The structural characterization of the samples was carried out by X-ray diffraction technique and it is found that, the phase transfer from cubic to orthorhombic perovskite structure. The lattice parameter and crystallite size decrease with increasing Mn content. The phase formation of perovskite was revealed by thermal analysis technique. The surface morphology and elemental analysis of all the samples were carried out by scanning electron microscopy and energy dispersive X-ray spectroscopic technique, respectively. Electrical properties of the compounds show that, they exhibit semiconducting behavior. The substitution of manganese ions plays an important role in changing their structural, electrical and magnetic properties of lanthanum ferrite. 相似文献
957.
958.
U. L. Basiniuk M. A. Levantsevich N. N. Maksimchenko A. I. Mardasevich 《Journal of Friction and Wear》2013,34(6):438-443
The results of a study on the technological capabilities of the modification of working profile of the teeth of the gears by nanostructured functionally oriented coating particles formed by the method of cladding by a flexible tool (CFT) and evaluated their impact on the reduction of generated tooth gearing noise. It is established that the efficiency of the technology CFT used for the noise reduction of bevel gear drives of machine tools is largely determined by the rational choice of the donor material composition for the formation of a coating. In some cases, gear teeth made from various materials formed on the working profile can significantly change the general character of the distribution of the frequencies of sound energy reducing the level of noise at one frequency and remaining unchanged or even higher at others. The best results in lower noise level of gearing in the whole spectrum of frequencies provided by the bronze-graphite Br05S20Gr0.5DMO0.5 coating. The decrease in noise at the general level was 2–4 dBA depending on rotation speed and, on a separate spectral component, reaches 6–9 dBA. 相似文献
959.
J. P. Tamang S. Dewan S. Thapa N. A. Olasupo U. Schillinger A. Wijaya 《Food Biotechnology》2013,27(1-2):99-112
Abstract This paper is the first report on the microbial population and predominant lactic acid bacteria (LAB) of two soft‐varieties (mild and strong flavoured) of chhurpi., a traditional cheese product of the Sikkim Himalayas. The enzymatic profiles and percentage hydrophobicity (as one criterion of potential adhesion capability) of the predominant LAB were also studied. The LAB, yeasts and viable mesophilic microbial numbers ranged from 7.6–7.9, 7.0–7.4 and 7.7–8.0 log10 cfu/g respectively. The predominant LAB were identified as Lactobacillus plantarum, Lb. curvatus, Lb. fermentum, Lb. paracasei subsp. pseudoplcmtarum and Leuconostoc mesenteroides. They produced a wide spectrum of enzymes and also exhibited similar patterns of enzymatic activity between species. In comparison to the peptidases, they showed relatively weak esterase and lipase activities. No proteinase activity was detected. Most strains had a high degree of hydrophobicity. The results are discussed in relation to the possible role of the strains in food processing. 相似文献
960.
D. Dietzel M. Feldmann C. Herding U. D. Schwarz A. Schirmeisen 《Tribology Letters》2010,39(3):273-281
Measuring interfacial friction during the manipulation of nanoparticles is becoming an increasingly important approach in
nanotribology research. In this work, antimony and gold particles deposited on flat graphite surfaces have been translated
by the tip of an atomic force microscope in contact mode along defined pathways. Two different manipulation techniques are
discussed with respect to pathway control and friction quantification. The first technique includes pushing the particles
from the side, which often results in a loss of the particle during translation due to unwanted sidewards motion. We analyze
this phenomenon with an analytical model and find good agreement with experiments. An alternative approach is to move the
particle while the tip remains on its top. We demonstrate that this approach allows better manipulation pathway control and
that simultaneous interfacial friction measurements are in quantitative agreement with the first manipulation method. 相似文献