Creep and Stress Relaxation in a Plate Loaded Along the Contour of a Circular Hole

Analytical solutions of the creep and stress-relaxation boundary-value problems of a plate loaded externally along the contour of a circular hole are obtained using an unsteady creep model based on nonclassical representations for elastic and viscous properties of materials. It is assumed that one force component and one displacement component are specified at the boundary.__________Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 4, pp. 146–153, July– August, 2005.     

On the approximate solution of autonomous boundary-value problems by the least-squares method

Using the least-squares method, we construct a new iterative procedure for finding solutions of an autonomous weakly nonlinear boundary-value problem in the critical case in the form of a generalized Fourier polynomial expansion.     

Positron spectroscopy of rehydrated pyrogeneous silica surface

Positron annihilation method has been used for investigating amorphous nonporous pyrogeneous silica of high purity. The influence of water adsorption on the structure of the silanol surface is shown. The effect of swelling, that is an increase of interglobular free volume at intermediate degrees of silica hydration has been observed.     

Electronic structure of the surface compounds ≡SiOElCl3 (El, = C,Si, Ge,Sn) and their thermal stability

The SCF MO LCA0 method in the MNDO approximation has been used to consider the electronic structure of the surface compounds SlODlCl₃ (El = C, Si, Ge, Sn), modelled by extended clusters. The thermal stabilities of these groups are compared and conclusions ore drawn about the probable mechanism of the interaction of the surface silanol groups of SiO₂ with ElCl₄ molecules.Institute for Surface Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 1, pp. 19–22, January–February, 1991. Original article submitted March 11, 1990.     

Spectral characteristics of the trypaflavine dye in a silica matrix

The mechanism of interaction of molecules of the dye trypaflavine with the surface and the bulk phase of silica gel has been investigated by electron spectroscopy. The character of the optical spectra of trypaflavine in a silica matrix is determined by the method of blending. Molecules of the dye are tied to the silicon dioxide substrate by an ionic bond; protonation of trypaflavine via the side amino groups and the acidic OH groups of the silica gel also takes place. In the simultaneous precipitation of the dye with polysilicic acid the encapsulated molecules possess an anomalously long afterglow, with extinguishment times ranging from tens of nanoseconds to seconds, which is not extinguished by oxygen. The mechanism of the retarded fluorescence of the adsorbed dye is discussed.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 6, pp. 748–753, November–December, 1985.     

Polarization in charge exchange reaction π−+p→π0+n at 40 GeV/c for the 4-momentum transfer range 0<|t|<2 (GeV/c)2

The results on measuring polarization in charge exchange reaction π^?+p→π⁰+n at 40 GeV/c are presented for the 4-momentum transfer range from 0 up to 2 (GeV/c)². At |t|≦0.4 (GeV/c)² the polarization has a positive sign. In the “crossover” region of π^± elastic scattering a possible minimum in the polarization behaviour has been seen for the first time. the polarization is zero within the statistical accuracy near this point. In the “deep” region of the charge-exchange differential cross-section the polarization has a negative sign. The presented data are not in agreement with the modern theoretical models.