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51.
Tatsuo Tokuoka 《Journal of Engineering Mathematics》1974,8(1):9-22
Summary The propagation velocities and the variation of the amplitudes of thermo-acoustical waves in thermo-plastic materials are
theoretically investigated. The constitutive equations of anisotropic thermo-plastic materials are derived from the concept
of imaginary decomposition of the deformation rate tensor into the elastic and plastic contributions and from that of the
plastic potential. From generalized Vernotte's heat conduction law the propagation condition of the jumps of the velocity
gradients and of the temperature rate is obtained. In isotropic materials and in the case of a normal stress vector on the
wave front we have two purely mechanical transverse waves and two thermo-longitudinal coupled waves. Formulae for the velocities
and amplitudes are quite similar with those for thermo-elastic materials. The variation of the amplitude is discussed. There
are, in general, three effects on the variation, that is, the non-planar, heat conduction and plastic flow effects. The transverse
waves are subjected only to the non-planar effect, while the thermo-longitudinal waves may grow or decay according to the
above three effects. 相似文献
52.
Tatsuo Tokuoka 《Journal of Engineering Mathematics》1973,7(4):361-366
Summary The growth and decay of the amplitudes of a thermo-longitudinal coupling wave of arbitrary form are investigated theoretically for isotropic linear thermo-elastic materials. As heat conduction law Vernotte's formula is adopted. Thomas' compatibility conditions of the second order for a singular surface of arbitrary form are used and the global behavior of the amplitude of the wave is analyzed. The geometrical effect of the wave front for the variation of amplitude depends upon the path length and the initial values of the mean and Gaussian curvatures. The thermal decay effect for the coupling wave is expressed as an exponential function of time and the damping factor is proportional to the thermal conductivity. 相似文献
53.
The formation of solid solution in the Co3−xMnxO4 system in atmospheres of oxygen, air and argon was examined at a constant temperature of 1000 °C. In oxygen, a small amount
of the NaCl-type compound was found to co-exist with the cubic spinel in the composition rangex≤0.1. A single phase of the cubic spinel was found in the range 0.1 to 1.3 and the tetragonal spinel above 1.9. In the rangex=1.3 to 1.9 where the cubic and tetragonal spinels co-exist they both have very broadened diffraction line profiles. In air,
the identified phases and the changes in their lattice constants with composition were very similar to those in oxygen, except
that the NaCl-type compound and the cubic spinel co-existed over a larger range. In argon, the cubic spinel was not observed
over any of the composition range and the NaCI-type compound and the tetragonal spinel co-existed in the wide range of 1.1
to 2.3. The experimental results are discussed with regard to the cation distribution in the spinel and also to the relative
stability of Co3+- and Mn3+-ions under the low partial pressure of oxygen. 相似文献
54.
H Tomoda M Hoshiai R Tagawa S Koide S Kawada A Shotsu S Matsuyama 《Canadian Metallurgical Quarterly》1980,100(3):306-310
Left atrial thrombi were evaluated with computed tomography in 23 patients with mitral valvular diseases. In three of the patients, left atrial thrombi were delineated with computed tomography and were confirmed by cardiac surgery or autopsy. The minimum size of the thrombi detected tomographically was 3.5 gm. There were no false-positive or false-negative results with computed tomography in 13 patients who subsequently underwent cardiac surgery. Computed tomography is essentially noninvasive and appears to be one of the best methods to evaluate left atrial thrombus. 相似文献
55.
Tominaga J Michizoe J Kamiya N Ichinose H Maruyama T Goto M 《Journal of Bioscience and Bioengineering》2004,98(1):14-19
Catalytic oxidation of biphenyl derivatives was investigated using laccase in a homogeneous aqueous-organic system. A thermostable laccase from Trametes sp. showed the highest catalytic activity for the oxidation of 4-hydroxybiphenyl (4-HB) at a reaction temperature of 60 degrees C when dimethylsulfoxide (DMSO) was employed as a co-solvent. Furthermore, the catalytic performance was successfully enhanced by the incorporation of a laccase mediator system (LMS) into the aqueous-DMSO media. The catalytic performance strongly depended on the type of mediator, and the highest activity was observed with 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as mediator, suggesting the importance of the selection of a suitable mediator. It was verified that this mediator system is applicable to the oxidation of several biphenyl derivatives with hydroxyl groups. 相似文献
56.
Crack-tip dislocations in silicon crystals have been examined by using high-voltage electron microscopy. Cracks were introduced by the Vickers indentation method at room temperature and the indented specimens were annealed at high temperatures to induce dislocations around crack tips under the presence of residual stress due to the indentation. A selected area around a crack tip was thinned by a focused ion beam (FIB) technique. Specimens were thinned in advance by a twin-blade cutting (TBC) method, which is a simple cutting process for saving FIB machine time. A combination of FIB and TBC can be a useful thinning procedure for the efficient preparation of transmission electron microscopy specimens. Characteristic dislocation structures were observed around the tip of a crack, aiding the elucidation of dislocation processes, which is essential to increase the fracture toughness of materials. 相似文献
57.
58.
Convex mirrors are universally used as rear-view mirrors in automobiles. However, the ocular accommodative responses during the use of these mirrors have not yet been examined. This study investigated the effects of a convex mirror on the ocular accommodative systems. Seven young adults with normal visual functions were ordered to binocularly watch an object in a convex or plane mirror. The accommodative responses were measured with an infrared optometer. The average of the accommodation of all subjects while viewing the object in the convex mirror were significantly nearer than in the plane mirror, although all subjects perceived the position of the object in the convex mirror as being farther away. Moreover, the fluctuations of accommodation were significantly larger for the convex mirror. The convex mirror caused the 'false recognition of distance', which induced the large accommodative fluctuations and blurred vision. Manufactures should consider the ocular accommodative responses as a new indicator for increasing automotive safety. 相似文献
59.
A large discrepancy between defect densities evaluated by constant photocurrent method (CPM) and electron spin resonance (ESR) is investigated for hydrogenated amorphous silicon (a-Si:H) with various thicknesses in the process of light soaking (LS). It is shown by a computer simulation that the inhomogeneous defect distribution across the film thickness caused by a rather small penetration depth of the white light in the thick film is one of the possible origins of the discrepancy. But various other causes should also bring about the discrepancy, and the problem is still a puzzling one. 相似文献
60.
Yusuke Kusuda Kinya Fukuda Masao Matsumura Kazuhisa Hagisawa Gaku Okamoto Tatsuo Nakanishi Yoshiyuki Inoue 《Electrical Engineering in Japan》2007,159(4):18-26
Recently, composite insulators have been increasingly employed mainly for economic reasons. We have developed a new type of outdoor termination using a composite insulator, which can be installed horizontally on a steel tower in order to reduce the construction cost. In this outdoor termination, SF6 gas is filled in the composite insulator and a cold shrinkable premolded rubber unit is applied instead of the combined use of a rubber‐molded stress relief cone, epoxy resin insulator and spring unit. The application of the composite insulator, SF6 gas and cold shrinkable premolded rubber unit reduces the total weight and makes it possible to install the termination horizontally on the tower. The new‐type outdoor termination for 77‐kV XLPE cable has already been applied in commercial use and enabled a reduction of the construction costs for power transmission lines. A 154‐kV new‐type outdoor termination has been developed and its initial electrical tests were successfully completed. This paper describes the design and performance of both 77‐kV and 154‐kV new‐type outdoor termination, and a follow‐up survey of the 77‐kV new termination in a commercial use. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 159(4): 18– 26, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20511 相似文献