Materials Literature
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Abstract Tunnelling recombination luminescence in CsI :Na crystals is studied by means of linear polarization, magnetic circular polarization, and optical detection of ESR either under or after X‐ray irradiation. Results are well interpreted in terms of a self‐trapped exciton (STE) scheme as the final emitting state o…
Tensile residual stresses induced by welding are an important factor in intergranular stress corrosion cracking (IGSCC) of Type 304 stainless steel pipes. Modified welding procedures can be used to prevent IGSCC by producing compressive residual stresses at potential crack initiation sites. This paper analyzes two pro…
Abstract. New data on the planktonic diatoms from the Gulf of Naples are presented together with those from the literature. Information is given on abundances, seasonal cycles and distributions of 183 taxa, including species, varieties and forms.
The crystal structure of the electron acceptor 2,5-difluoro-7,7,8,8-tetracyano-p-quinodimethane, 2,5-TCNQF2, has been determined by single-crystal X-ray diffraction methods. The layered crystal structure is dominated by the antiparallel coupling of cyano bond moments of symmetry-related molecules. The molecular and el…
The crystal and molecular structure of N-(4-n octyloxybenzylidene)-4'-butylaniline (80.4), C25H35NO, has been determined at room temperature partially by direct methods and completed by subsequent Fourier synthesis. The crystals belong to the triclinic system with space group P1, a=5.452(3), b=7.948(4), c=27.356(4) Å,…
The twinned crystal structure of the charge-transfer complex TTF-2,5-TCNQF2 has been determined by single-crystal X-ray diffraction techniques. From intensity measurement on one twin component, a full structural model has been developed. The model encompasses segregated stacks of TTF donors and 2,5-TCNQF2 acceptors, w…
Three conformational polymorphs of Ni(NCS)2(P(CH2CH2CN)3)2 have been synthesized and their crystal structures determined by single-crystal X-ray diffraction techniques. All three crystallize in space group P21/c: cell constants for polymorph 1, a = 13.44(2) A, b = 9.04(1) A, c = 24.45(2) A, and beta = 115.4(1) degrees…
This article describes the effect of the extrusion conditions on PVC processing, morphology, and physical properties. In agreement with several previous reports, the PVC particulate hierarchy is successively broken down during processing. In particular, the 100—150-μm PVC grains are broken down to 10-μm agglomerates a…
Abstract The new compound Na 6 Si 2 Te 6 crystallizes in the monoclinic system (space group P 2 1 /c) with a = 878.6(3) pm, b = 1278.0(4) pm, c = 886.4(3) pm, β = 119.71(5)°. The compound is isotypic to K 6 Sn 2 Te 6 , essential structure elements are [Si 2 Te 6 ] 6- anions.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHopping and delocalized electrons in class II mixed-valence oxovanadatesSubhash P. Harmalker and Michael T. PopeCite this: J. Am. Chem. Soc. 1981, 103, 24, 7381–7383Publication Date (Print):December 1, 1981Publication History Published online1 May 2002Published inissue 1 Dec…
Two types of portable instruments were developed by the former Health and Safety Laboratory of the U.S. Atomic Energy Commission to characterize external gamma radiation fields and to estimate individual exposure dose rates from major natural or fission radionuclides distributed in the soil: a pressurized ionization c…
Abstract Plasma modification of polyethylene is modeled most simply as a process generating a two phase polymer system: a thin hydrophilic surface phase and a relatively unperturbed hydrophobic bulk phase. The oxidized surface of polyethylene exposed to a N (PEN) or to an Ar (PEAr) glow discharge plasma contains fun…
The powder data for anhydrous theophylline (1,3-dimethylxanthine), C 7 H 8 N 4 O 2 , are reported. It is orthorhombic, Pna 2 1 , with a = 24.628 (4), b = 3.833 (2), c = 8.501 (5) Å; U = 802.49 Å 3 ; Z = 4; D m = 1.478, D c = 1.489 Mg m −3 .
New Monte Carlo simulations of electron scattering based on the single scattering model have been performed in the low-energy region for an aluminum target, where two basic equations are required, namely the elastic scattering cross section and the energy-loss rate. We investigated the screened Rutherford equation and…
The behavior of molybdenite in the system Na 2 Si 2 O 5 -K 2 Si 2 O 5 -MoS 2 -H 2 O has been investigated from 340 bars to 1.36 kb in the temperature range 450 degrees to 850 degrees C. Phase relations in the system show enhanced molybdenite solubility in the alkali silicate liquids and coexisting vapors. MoS 2 solubi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAbsolute rate constants for hydrocarbon autoxidation. 31. Autoxidation of cumene in the presence of tertiary aminesJ. A. Howard and T. YamadaCite this: J. Am. Chem. Soc. 1981, 103, 24, 7102–7106Publication Date (Print):December 1, 1981Publication History Published online1 Ma…
By means of crystal etching and scanning electron microscopy the c- and a- axes of skeletal units of Strongylocentrotus purpuratus have been determined. Crystal etching and crystal decoration were found to be equally useful in demonstrating that the spines are single crystals of magnesian calcite. All regions of spine…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron-transfer chemistry of the luminescent excited state of octachlorodirhenate(III)Daniel G. Nocera and Harry B. GrayCite this: J. Am. Chem. Soc. 1981, 103, 24, 7349–7350Publication Date (Print):December 1, 1981Publication History Published online1 May 2002Published ini…
Factors responsible for the high extent of intracellular posttranslational modifications in type IV collagens were studied in a cultured human tumor cell line, HT-1080. These cells do not synthesize any detectable amounts of interstitial collagens but produce type IV collagen at a high rate, corresponding to about one…
Abstract The kinetics and equilibria of SO 2 sorption in Kapton polyimide film have been studied at temperatures from 25 to 55°C and equilibrium sorption pressures up to 0.76 atm. The data are described well by the dual‐mode model of sorption and transport in glassy polymers. The assumption of “partial immobilization”…