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J Vanícek

Publications and source records attributed to J Vanícek.

4 recordsLinked to original sources

Replacement manifolds: a method to uniformize semiclassical wave functions.

We present a semiclassical technique that relies on replacing complicated classical manifold structure with simpler manifolds, which are then evaluated by the usual semiclassical rules. Under circumstances where the original manifold structure gives poor or useless results semiclassically the replacement manifolds can yield remarkable accuracy. We give several working examples to illustrate the theory presented here.

Journal Article↗

Preparation and strength of poly(ethylene terephthalate) fiber bundles for model synthetic tendons.

Poly(ethylene terephthalate) fibers suited for model synthetic tendons were prepared on a pilot-plant scale by additional drawing (postdrawing) of commercial textile fibers texturized by false twist. The modified fibers have a tensile modulus of 7-9 GPa, a one-minute creep modulus of 5-6 GPa, tensile strength 0.55-0.63 GPa, and strain at break of 16-19%. It is essential for their application in synthetic tendons that plastic deformation was reduced to about 0.5%, which could be completely eliminated by subsequent mechanical conditioning of fibers. Since the strength of model tendons consisting of 20 vol % of fibers and of a hydrogel matrix is primarily determined by the strength of the fibers, some aspects of the theory of strength of fiber bundles are briefly recapitulated. The prediction is compared with earlier experimental results obtained for the synthetic tendons. Such an approach, taking into account the fiber-strength distribution in the bundle, predicts a strength of model tendons lower by 20-40% than does the rule of mixtures.

Polyethylene Terephthalates↗

Induction of abortion with prostaglandin F(2)alpha in gilts and their subsequent fertility.

Fourteen gilts were aborted (some of them repeatedly) by i.m. administration of 500/ug cloprostenol (PG) between 30 and 100 days of pregnancy so that the total number of PG-induced abortions was 19. Six of these gilts were allowed to terminate their subsequent pregnancy by farrowing. It was found that In a Trial under semi-production conditions the mean birth body mass of piglets from 11 gilts bred after previous PG-induced abortion was 1.48 kg as compared to 1.19 kg in the controls. The difference was significant (P<0.01).

Journal Article↗