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Abstract Three homologous cofacial diporphyrins that have interplanar distances ranging from 6.4Å to 4.2Å have been synthesized. Their absorption and emission spectra revealed strong exciton coupling in the diporphyrin. Magnesium complexes of diporphyrins were studied and their application as a model for P700 photoact…
Magnetic properties of the compounds RMn2 and RMn23 (R=Y, Lu, Gd, and Th) were studied before and after hydrogen absorption. Hydrogen-induced transitions from Pauli paramagnetism to ferromagnetism were observed in YMn2, LuMn2, and Th6Mn23. The reverse effect, i.e., changes from ferromagnetism to Pauli paramagnetism, w…
Abstract Ultraviolet and Fourier‐transform infrared spectroscopy are used to characterize the chain conformation of 2,6‐dimethyl poly(phenylene oxide) (2MPPO) in compatible 2MPPO‐polystyrene (PS) blends. Blending with PS increases the intramolecular energy of the 2MPPO. Atactic PS induces a greater distortion from the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure of Poly(1,4-benzamide) SolutionsM. Panar and L. F. BesteCite this: Macromolecules 1977, 10, 6, 1401–1406Publication Date (Print):November 1, 1977Publication History Published online1 May 2002Published inissue 1 November 1977https://pubs.acs.org/doi/10.1021/ma60060a…
Abstract Polyurethane elastomers are a numerous group of polymeric materials of wide practical application. They are usually formed by polyaddition of diisocyanates with hydroxyl-terminated polyesters or polyethers in the presence of low molecular weight diols or diamines as chain extenders. One may consider urethane…
Abstract. Greening tissues accumulate Mg‐protoporphyrin monoester and a group of metalloporphyrins that exhibit fluorescence emission and excitation properties which are red‐shifted with respect to Mg‐protoporphyrin monoester. These metalloporphyrins are collectively termed longer wavelength metalloporphyrins and are…
Abstract Photoreversible reactions of 1,4‐butanediol dicinnamylideneacetate(BCA) and its photocyclized compound (BCD), the model compounds for poly(vinyl cinnamylideneacetate), were studied. They exhibited an excellent photoreversibility in a rigid medium at 77°K. The quantum yield of dimerization in the rigid medium…
A series of cardanol derivatives prepared in a preceding study1 are evaluated as PVC plasticizers. These include butyl anacardate (3), cyclohexyl anacardate (4), 3-(pentadec-8′-enyl)phenyl acetate (5), 3-(8′,9′-diacetoxypentadecyl)phenyl acetate (6), and 3-(8′-epoxypentadecyl)phenyl acetate (7). The evaluation initial…
The optical transmission of Ti4O7 single crystals has been measured in the infrared at wavelengths between 3·8 and 6·8 μ in the temperature range of the metal-insulator transitions. In the low temperature phase (T>140K), the data are characteristic of a semiconductor with an optical gap of ∼ 0·25 eV. In both the inter…
Abstract The processes of the solid state reaction of Y2O3 with WO3 were studied for samples mixed in the molar ratios of Y2O3 : WO3=1 : 3, 1 : 1, 7 : 4, 5 : 2, and 3 : 1. It was found that all the reactions except Y2O3 : WO3= 5 : 2 from the powders of both Y2O3 and WO3 in air proceeded according to the following orde…
Binding energies for the core levels of scandium metal and its oxide and hydride are recorded. Plasmon energy-loss peaks are observed for the metal and show a large shift on hydriding, approximately 3.7 eV, compared with a shift of approximately 0.2 eV for the 2p core levels. The large plasmon shift is consistent with…
In Bacillus subtilis the trpX locus specifies a glutamine-binding protein designated subunit X, which forms a complex with subunit E to constitute the anthranilate synthase enzyme aggregate (EX) and subunit A to constitute the p-aminobenzoate synthase enzyme aggregate (AX). Subunit X confers upon these enzyme complexe…
A theory is described which, for any universal structure invariant or structure seminvariant, Φ, is able to arrange the set of reflexions in shells, each shell a subset of the succeeding one, with the property that Φ may be estimated in terms of the magnitudes constituting any shell. The theory uses the idea that numb…
Abstract Polymerization of sarcosine N ‐carboxyanhydride was carried out in N , N ‐dimethylformamide solution with some primary and secondary amines as initiators. The polymerization obeyed the first‐order kinetics. Polysarcosines obtained were fractionated by gel‐chromatography. For lower oligomers, individual oligom…
This is the first of three presentations conceived to improve the operator's understanding of the process of pipe protection by calcium carbonate precipitation.
The crystal structure of Mn/sub 3/(Co(CN)/sub 6/)/sub 2/.12H/sub 2/O has been determined by neutron and x-ray diffraction methods and that of Cd/sub 3/(Co(CN)/sub 6/)/sub 2/.12H/sub 2/O by the latter method. In both cases, the space group is Fm3M with lattice constants of 10.436 (3) and 10.600 (3) A, respectively. The…
Abstract Einkristalluntersuchungen zufolge leitet sich die Kristallstruktur von Na 3 NO 3 ≙ (NO )ONa 3 + vom anti‐Perowskittyp ab (a = 4,605 Å, Pm3m); das Nitrit‐Anion ist fehlgeordnet.
The general energy analysis of fabric mechanics by means of optimal control presented in a previous publication is applied to the woven-fabric structure for deformations whereby the yarns remain in the same plane. The three-dimensional equations of the general theory are reduced to two-dimensional form, the boundary c…
The changes in the x-ray diffraction patterns of 16- and 25-μm-thick polyvinylidene fluoride films, caused by 6-kV corona charging at room temperature, are presented. The diffraction peaks corresponding to (100) and (020) α-crystalline forms tend to be considerably reduced while the (110) β-form peak changes in shape…
The phase diagram of the system ZrO 2 ‐CaO for the region ZrO 2 ‐CaZrO 3 was redetermined. The extent of the cubic solid solution field was ascertained by using a high‐temperature X‐ray furnace, precise lattice parameter measurements, and a hydrothermal technique. At 850 ± 150°C, the cubic solid solutions decompose by…