Materials Literature
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Color evaluation, surface morphology, amino acid composition, solubility and molecular weight distributions are used to describe the initial degradative changes in Bombyx mori silk fibroin resulting primarily from irradiation with UV and visible light. The biochemical techniques are more sensitive detectors of the ini…
The mechanical properties of major ampulate gland silk fibers extracted from Nephila clavipes (Araneae, Tetragnathidae) spiders are presented. Stress-strain response at conventional tensile testing rates (ca. 10%/s), and at very high strain rates (ca. 1,000,000%/s) are characterized. Fiber surface topography indicates…
Models for the molecular networks present in the frame and viscid silks of the spider, Araneus diadematus, have been developed from the non-Gaussian mechanical behaviour of these silks when tested in their elastomeric state. Frame silk contains a short chain network, crosslinked by β-sheet crystals, where the network…
Larvae of the silkworm, Bombyx mori, control the molecular orientation of their cocoon fiber with several sophisticated spinning techniques. This chapter reviews the interactions of behavior, morphology, and biochemistry in the production of silkworm silk. Numerous physical and chemical variables can induce transition…
General Biology Silks are produced by the more than 30,000 known species of spider [1], and by most of the 113,000 species in the insect order Lepidoptera [2]. In addition, silks are produced by members of several other insect orders [3]. For every silk that has been characterized in any detail, over 1000 uncharacteri…
Molecular-based magnets with high magnetic-ordering temperatures, T(c), can be obtained by mild chemistry methods by focusing on the bimetallic and mixed-valence transition metal micro-cyanide of the Prussian blue family. A simple orbital model was used to predict the electronic structure of the metal ions required to…
In a thin film geometry symmetric block copolymers self-assemble to form well-oriented multilayered structures, ideally suited for study by reflectivity techniques. Neutron reflectivity was performed on selectively deuterated poly(styrene-b-methyl methacrylate) copolymers to determine quantitatively the spatial distri…
We report here the parallel implementation of an original algorithm allowing a fast calculation of the distance matrix D of a graph representing a given chemical structure (molecule, polymer, crystal, etc.). Our algorithm fits perfectly in the SIMD parallel architecture of the Connection Machines CM-200 as we shall sh…
A new method for detecting the initial susceptibility of ferromagnetic materials by recording an induced voltage is described and applied to measurements on grain oriented silicon steel. The significantly different results in dependence of the initial susceptibility on the crystallographic directions can be interprete…
Coatings with Pd-Ni predeposit alloys have been processed using various aluminizing treatments : low and high activity cements, pack and vapor phase coatings. Their metallurgical structure has been investigated with a special emphasis on the repartition of the various metallic elements throughout the coating section.…
Perturbed angular correlation (PAC) of nuclear radiation has proven to be a useful tool for the characterization of materials. The technique makes use of the hyperfine interaction between the nuclear electromagnetic moments and the electromagnetic environment in which the nucleus finds itself. It is sensitive to the s…
A basic study on hydrophilicity of gelatin was made of the fitness, water-absorbing ability, water-holding ability, affinity and stability of included water in order to utilize it as a protective covering for medical use. Gelatin No. 3, being highly viscous and having a lower jelly strength, was strongly viscous and f…
The linearized shape stability of melting and solidifying fronts with surface tension is discussed in this paper by using asymptotic analysis. We show that the melting problem is always linearly stable regardless of the presence of surface tension, and that the solidification problem is linearly unstable without surfa…
Abstract The tensile drawing of polyethylene terephthalate fibers spun from polymer of high and low molecular weight over a range of windup speeds has been studied. An analysis of the mechanical properties, orientation, and shrinkage behavior for different draw ratios leads to two conclusions. First, the network struc…
Resonance polarization-sensitive coherent anti-Stokes Raman scattering (PS CARS) spectra of the electronic ground state and excited singlet S 1 state of rhodamine 6G in ethanol were obtained with the use of the pump-probe technique with nanosecond time resolution. Variation of the polarization orientation of the pump…
Abstract Caryinite from Långban, Sweden is associated with barite, richterite, manganberzeliite, hedyphane, sarkinite or eveite, and an exsolved fermorite-like mineral. The crystal structure of caryinite, space group I2/a, a 6.855(2), b 13.147(3), c 11.479 (4) Å, β 98.97°, V 1022.0(5) Å 3 , has been refined to a conve…
Molecular oxygen or cytochrome c has been described as the electron acceptor of the reaction of old yellow enzyme with NADPH. In this study, menadione was found to be a sensitive electron acceptor of the reaction under aerobic as well as anaerobic conditions. The Km value of menadione for old yellow enzyme is as low a…
Abstract The rate of aerial oxidation of the title porphyrin ( 1 ) in dichloromethane (DCM), acidified with trifluoro‐acetic acid (TFA), was found to be first‐order in 1 and second‐order in TFA at low TFA concentrations, and second‐order in both 1 and TFA at higher TFA concentrations. At the lower TFA concentrations,…
The emission spectra of KBr and KCl were obtained in the temperature range 18--290 K during the thermoluminescence (TL) measurements and 40--300 K during the cathodoluminescence (CL) measurements. The 400--600 nm broad emission bands in KBr and KCl at low temperatures are resolved into at least two components: the sel…
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