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Tsviatko Rangelov Yonko Stoynov Petia Dineva 《International Journal of Solids and Structures》2011,48(20):2987-2999
Dynamic anti-plane fracture problem of an exponentially graded linear magnetoelectroelastic plane with a finite impermeable crack subjected to time-harmonic SH-waves is solved. Directions of wave propagation and material inhomogeneity are chosen in an arbitrary way. The fundamental solution for the coupled system of partial differential equations with variable coefficients is derived in a closed form by the hybrid usage of both an appropriate algebraic transformation for the displacement vector and the Radon transform. The formulated boundary-value problem is solved by a nonhypersingular traction boundary integral equation method (BIEM). The collocation method and parabolic approximation for the unknown generalized crack opening displacements are used for the numerical solution of the posed problem. Quarter point elements placed next to the crack-tips ensure properly modeling the singular behavior of the field variables around the crack tip. Fracture parameters as stress intensity factor, electric field intensity factor and magnetic field intensity factor are computed. Intensive simulations reveal the sensitivity of the generalized intensity factors (GIF) at the crack-tips to the material inhomogeneity, characteristics of the incident wave, coupling effects, wave-material and wave-crack interaction phenomena. 相似文献
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E. S. Stoynov V. A. Mikhailov V. G. Torgov T. V. Us 《Journal of Structural Chemistry》1994,35(6):809-816
This paper reprots of31P NMR and IR studies of the interaction of tributyl phosphate (TBP) and di-n-octyl sulfoxide (DOSO) with polymer molecules
of uranyl di-2-ethylhexyl phosphate (UO2X2)p (I) in C6H6 sulutions. Detailed interpretations of the31P NMR spectra and the vas(POO) IR bands and determination of the fraction of nonequivalent phosphorus atoms of X− anions and uranium (VI) atoms as well as the concentration of U(VI)-bonded TBP in I have shown that only a single TBP or
DOSO molecule is coordinated to the uranium atoms of polymer I at CTBP=0.1–2 M or CDOSO=0.1–0.5 M. In the case of 100% TBP, two TBP molecules are coordinated to some U(VI) atoms. Distribution of TBP (DOSO) molecules
along the polymer chain agrees with the mean statistical value. The portion of terminal chalate POO-groups of X− anions is determined. The dependence of the degree of (UO2X2)p·nL (L=TBP, DOSO) polymerization on CL is obtained. Saturation of solutions with water only slightly affects the terminal POO-groups and has no effects on the distribution
of L along the polymer chain of I.
Institute of Catalysis, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 35, No. 6, pp. 66–73, November–December, 1994.
Translated by K. Shaposhnikova 相似文献
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P. Stoynov 《Journal of Mathematical Sciences》2004,121(5):2692-2697
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Zdravko B. Stoynov Daria E. Vladikova Emiliya A. Mladenova 《Journal of Solid State Electrochemistry》2013,17(2):555-560
Water behavior studies were performed in porous ceramic media based on proton conducting yttrium-doped barium cerate BaCe0.85Y0.15O3-α (BCY15), which is a component of a new high-temperature dual membrane fuel cell (dmFC) design. Complex permittivity measurements were carried out on porous samples at room temperature. A new phenomenon was observed during wetting—a gigantic enhancement of the real component of the capacitance at lower frequencies. A possible explanation is the formation of semi-liquid layer with dipole structure on the pores walls, which is supposed to be organized also at operating temperatures. Since the electrochemically active volumetric layer facilitates the water formation, it should improve the operation of the dmFC by decreasing its resistance, which is experimentally confirmed. This phenomenon can be of importance also for classical proton conducting solid oxide fuel cells, as well as for operation in electrolyzer mode. 相似文献
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