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102.
Elastic solutions of a cylindrical rod containing periodically distributed inclusions with axisymmetric eigenstrains 总被引:1,自引:0,他引:1
Summary. In this paper, we give the elastic solution for a special type of microstructure – a circular cylindrical rod containing periodically distributed inclusions along its axial direction. Each inclusion has the same uniform axisymmetric transformation strain (eigenstrain). Analytical elastic solutions are obtained for the displacements, stresses and elastic strain energy of the rod. The effects of microstructure and its evolution (growth of inclusions) on the elastic stress and strain fields as well as the strain energy of the rod are quantitatively demonstrated. As a result of such microstructure evolution nominal stress-strain relation with strain softening is derived for a rod under uniaxial tension. 相似文献
103.
Summary Sedimentation experiments and X-ray photoelectron spectroscopy (XPS or ESCA) analyses have been used to study the effect of poly(methylmethacrylate) (PMMA) tacticity on aluminum oxide powder dispersion stability in a common solvent medium. The relative trends from sedimentation densities, and from surface analyses after solvent washing show that (PMMA) adsorption is greatest with isotactic polymer, where isotactic>atactic>syndiotactic adsorption. These results suggest that surface adsorption and hence dispersion stability can be influenced by polymer chain configuration as well as by chain conformation. 相似文献
104.
乙烯-1-辛烯共聚物增韧应用研究 总被引:3,自引:0,他引:3
介绍了聚烯烃系弹性体(POE)的特点及其在PP增韧改性中的应用,同时还报道了马来酸酐接枝的POE在极性聚合物复合体系中的应用研究。 相似文献
105.
JL Stringer 《Canadian Metallurgical Quarterly》1995,68(2):407-413
In a particular brain region specific changes in inhibition or excitation may be the basis of seizure initiation. Alternatively, changes in the balance of excitation and inhibition in the circuit, which may be detectable as polysynaptic responses may be more important indicators of epileptogenesis. That the appearance of polysynaptic responses precedes the initiation and, therefore, may be necessary for the onset of epileptiform activity in the hippocampal-parahippocampal circuit was tested using the chemical convulsant pentylenetetrazol. Excitation and paired-pulse inhibition were measured in CA1 and the dentate gyrus of the urethane-anaesthetized rat before and after administration of pentylenetetrazol. In addition, three polysynaptic responses were monitored. In both CA1 and the dentate gyrus, pentylenetetrazol, 100 mg/kg, caused a trend towards increased excitability and caused a relatively mild loss of inhibition. Two polysynaptic responses appeared in the dentate gyrus after the administration of pentylenetratrazol, both apparently mediated through the entorhinal cortex. A polysynaptic response of the CA1 pyramidal neurons to contralateral angular bundle stimulation was not observed. These experiments demonstrate that pentylenetetrazol will facilitate only the appearance of polysynaptic responses mediated through the entorhinal cortex. These results support the hypothesis that pentylenetetrazol has a specific action within the entorhinal cortex that may facilitate the synchronization and spread of epileptiform activity. These results are also consistent with the hypothesis that the appearance of polysynaptic responses may be necessary for the onset of epileptogenesis in the hippocampal-parahippocampal circuit. 相似文献
106.
火电厂实施废水零排放的可行性探讨 总被引:1,自引:0,他引:1
对合肥发电厂的用排水现状进行了介绍,并提出了实施废水零排放的可行性方案。 相似文献
107.
The method of reverberation ray matrix is applied to analyze the dynamic behavior of structural members in trusses with pinned joints subjected to suddenly applied force. The results are compared with those in planar trusses with rigid joints. Detailed calculations are made with two types of trusses, a small laboratory model made of slender aluminum bars, and a hypothetical real size Pratt truss made of structural steel. It is found that the maximum dynamic bending strains in the members of both types of trusses are very large, comparable with the dynamic axial strains in the same member. The magnitudes of bending strains in the pinned truss differs little from those in the truss with rigid joints for both types of trusses. Such a large dynamic bending strain in a structure member, which is contradictory to the static behavior of the same truss, could be caused by the inertial force of the mass in structural members of the truss. 相似文献
108.
Z. M. Sun Z. G. Wang H. Hdl B. Weiss R. Sticker 《Materialwissenschaft und Werkstofftechnik》1995,26(9):483-487
The deformation behavior of pure recrystallized molybdenum under cyclic and static loads was investigated in the temperature range between 30°C and 10O°C, for stress amplitudes between 100 MPa and 250 MPa and for static loads up to 200 MPa. The results show that in spite of the low test temperatures and stress levels the Mo material exhibits considerable plastic strains which depend sensitively on frequenez and small changes in temperature.The activation energy deduced for the static and dynamic deformation is less than 0.98 eV which indicates thermally activated processes, to be explained by a dislocation kink model as described in the literature. The low-temperature fatigue behavior appears strongly influenced by creep-fatigue interaction phenomena. 相似文献
109.
Eighty-six children who completed immunization with the two trivalent poliovirus vaccines, live attenuated (OPV) and enhanced potency inactivated (EIPV), in one of four schedules (OPV-OPV-OPV, EIPV-EIPV-EIPV, EIPV-OPV-OPV, and EIPV-EIPV-OPV) at 1 year of age were monitored serologically over the subsequent 4 years and challenged with OPV at 5 years of age. Each of the immunization groups exhibited an initial 10- to 100-fold decline in neutralizing antibody to poliovirus types 1, 2, and 3 during the first 2 years of follow-up; thereafter antibody titers stabilized. The EIPV-EIPV-OPV group maintained the highest antibody levels throughout the observation period, including the response to OPV challenge at 5 years of age. These data suggest that immunization with OPV, EIPV, and combinations of the two vaccines confers long-term immunity. Optimal systemic immunity was associated with two or more doses of EIPV. 相似文献