A mechanical view of transformation-induced plasticity

Summary A mechanical framework on the transformation-induced plasticity (TRIP) is presented. Numerical illustration of the theory can well explain such phenomena in TRIP as a remarkable increase in elongation at a certain range of temperature in the uniaxial tensile tests and the effect of the residual austenite.

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Eine mechanische Theorie über die umwandlungsinduzierte Plastizität

Übersicht Eine mechanische Theorie über die umwandlungsinduzierte Plastizität (TRIP) wird präsentiert. Es wird durch numerische Illustration gezeigt, daß die Theorie solche Phänomene in TRIP wie eine bemerkenswerte Zunahme der Umformung beim Zugversuch in einem gewissen Temperaturbereich und den Einfluß des residualen Austenit gut beschreiben kann.

     

Palladium(O)-catalyzed allylic alkylation and amination of allylic phosphates

Allyl diethyl phosphates (1) can be easily substituted with malonates and amines in the presence of palladium(O) catalyst. Synthetic utility of the reaction is demonstrated by the sequential amination-amination and alkylation-amination of (Z)-4-acetoxybut-2-enyl diethyl phosphate (1b) with high regio- and stereoselectivity.     

Carbon-13 NMR spectra of retinal1 and its related compounds

Carbon-13 NMR spectra of all-trans retinal₁ and vitamin A₁ were measured by the pulse Fourier transform method in CCl₄. All peaks in these spectra were assigned from considerations of chemical shifts, half proton-decoupled spectra, spin-lattice relaxation times and induced chemical shift by the addition of shift reagent. The carbon-13 NMR spectrum was also measured for all-trans retinal₁ which had been exposed to the sunlight for three hours, and the induced isomer was proposed to be 11-s-cis retinal₁.     

Angle-resolved photoemission study of CoSi2 nanofilms grown on Si(111) substrates

We have carried out an angle-resolved photoemission study for CoSi₂ nanofilms grown on the Si(111)-7×7 substrates. The surface of CoSi₂(111) nanofilm changes from the bulk-truncated surface to the surface with additional Si-bilayer by annealing at higher temperature above 825 K. The angle-resolved photoemission spectra of the CoSi₂ nanofilm annealed at 853 K show the spectral features originated from the surface resonance state on the CoSi₂ surface terminated by Si-bilayer. From the detailed photoemission study, we discuss the surface electronic structure in CoSi₂(111) nanofilms grown on Si(111) substrates.     

Syntheses of tetraoxaquaterene derivatives

Several new dimethyl and tetramethyl tetraoxaquaterenes, 3d and 3e , have been prepared in order to synthesize the oxygen analogues of porphyrin. The reaction between furan and a ketone using an acidic catalyst gave the cyclic tetramer, tetraquaterene, and oligomers. On the other hand, in the case of furan and an aldehyde, only linear oligomers were isolated. The condensation of furan-containing dimers with carbonyl compounds, both ketone and aldehyde, except formaldehyde, gave the tetraoxaquaterene. In the case of formaldehyde, the yield of cyclic tetramer was negligible.     

Study of boron nitride by electron energy-loss spectroscopy

An interband π plasmon and π* edge have been observed in the spectrum of hexagonal boron nitride (h-BN). This result is in good agreement with that     

Azimuthal anisotropy in low-energy ion scattering from SmB6 (001)

A remarkable azimuthal anisotropy has been observed in the scattering of He⁺ ions of an incident energy of 1 KeV from the SmB₆(001) surface. The anisotropy can be interpreted on the basis of “shadowing” effects and clearly reflects the structure of the surface.