An upper bound approach on yield surfaces of porous materials

Summary Triaxial deformation of a porous material is analyzed. A material model is proposed where the material consists of spherical cells each of which has a spherical pore in the center of the matrix. The velocity field in the matrix is assumed and the upper bound approach is attempted. The yield surfaces of the porous materials with various volume fractions of pores v _f are obtained as ellipsoids whose axes become smaller with increasing v _f.They coincide with the yield surfaces which have been proposed by the authors earlier.

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Ein Obere-Schranken-Ansatz für den Fließort von porösem Material

Übersicht Analysiert wird die dreiachsige Deformation eines porösen Werkstoffs, der durch kugelförmige Zellen mit sphärischen Löchern im Zentrum der Matrix modelliert wird. Für die Anwendung des Obere-Schranken-Satzes wird ein Geschwindigkeitsfeld in der Matrix angesetzt. Damit erhält man als Fließort von porösen Werkstoffen mit verschiedenen Porenvolumen-Anteilen v _fEllipsoide, deren Hauptachsen mit zunehmendem v _fkleiner werden. Sie stimmen mit den Fließorten, welche die Autoren schon früher halbexperimentell und halb-analytisch ermittelt haben, überein.

     

Synthesis of Acid-Resistant P-Quinone Monoketals and Thermally Stable 4,4-Dialkoxycyclohexa-2,5-Dien-1-OLS

Preparation and high resistance to acid hydrolysis of sterically hindered p-quinone monoketals 1a, 1b and 1c are described. Thermal stability of ketal alcohols 2a and 2b derived from 1a and 1c, respectively, is also mentioned.     

Universal fluorescent labeling of amplification products using locked nucleic acids

Amplification/hybridization‐based genetic analyses using primers containing locked nucleic acids (LNAs) present many benefits. Here, we developed a novel design for universal fluorescent PCR using LNAs. Universal fluorescent PCR generates intermediate nonlabeled fragments and final fluorescent fragments in a two‐step amplification process that uses locus‐specific primers with universal tails and universal fluorescent primers. In this study, a few standard nucleotides were replaced with LNAs only in the fluorescent universal primers. The sequence of the fluorescent universal primer significantly affected the amplification efficiency. For primers with three LNAs, the fluorescent primers with stable M13(‐47) sequences provided the most efficient signal (approximately tenfold higher than the primers with M13(‐21) sequences at lower Tm values). Moreover, AT‐rich LNA substitutions in the fluorescent primers produced much lower amplification efficiencies than GC‐rich substitutions. GC‐rich LNAs produced greater differences in Tm values among primers, and resulted in the preferential production of fluorescently labeled amplicons. The specificity and sensitivity of LNA‐containing fluorescent primers were assessed by genotyping eight STRs in Japanese individuals, and full STR profiles could be generated using as little as 0.25 ng of genomic DNA. The method permitted clear discrimination of alleles and represents sensitive STR genotyping at a reduced cost.     

Full-parallax three-dimensional display based on light field reproduction

Optical Review - Light field displays can display three-dimensional (3D) images with smooth motion parallax without the use of special glasses, by reproducing light ray information from objects....     

Tensyuic acids, new antibiotics produced by Aspergillus niger FKI-2342

Six new alkylitaconic acids, designated tensyuic acids A to F, were isolated from the culture broth of Aspergillus niger FKI-2342 by solvent extraction, silica gel column chromatography and HPLC. Their structures were elucidated by spectroscopic analysis including UV, NMR, and MS. They are all alkylitaconic acid derivatives. Only tesyuic acid C showed moderate antimicrobial activity against Bacillus subtilis.     

Addition reactions of cyclooctatetraene with 1,3-diphenylisobenzofuran the benzene ring as dienophile in a [4+2] cycloaddition reaction

Addition reactions of cyclooctatetraene with 1,3-diphenylisobenzofuran resulted in the formation of three 1:1 cycloadducts, 1, 2, and 3, and a 1:2 cycloadduct, 4. Single crystal x-ray analysis established 3 to be a cage compound formed by an unprecedented [4+2] cycloaddition reaction of 1 in which the double bond of the benzene moiety acted as the dienophile.