Materials Literature
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Poly(3-hydroxybutyrate) (PHB) microspheres containing 10wt% of lastet, an anticancer drug, were prepared by a solvent-evaporation process. The release rate of lastet from PHB microspheres in vitro (in 0.01M phosphate buffer) was significantly increased by incorporating glycerol tristearate as an additive. The signific…
Ilyanassa obsoleta larvae have two calcium carbonate-containing organs, shell and statocyst, which are derived from five micromere cells (2a, 2c, 2d, 3c, 3d). "Internal shell," an abnormal, internal calcium carbonate mass, was previously observed when cells which normally induce shell and statocyst were removed. This…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRing expansion of halo dithiolanes and dithianes: a facile synthesis of medium-ring dithiacycloalkenesZhihua Sui, Paul S. Furth, and James J. De VossCite this: J. Org. Chem. 1992, 57, 24, 6658–6662Publication Date (Print):November 1, 1992Publication History Published online1…
Abstract It is a well‐known fact that the permeability of polymer materials increases as the temperature increases. As the temperature drops to its original level, the permeability in many instances does the same. When packages are processed in an autoclave, the material will be exposed to both high temperature and hi…
The FPL (Forest Products Laboratories) Process for preparing aluminum for structural adhesive bonding has been used in the aerospace industry since the early 1950's. Problems were encountered with the use of the process when the industry changed from phenolic to epoxy adhesives. In-service disbonds followed by corrosi…
For pt.XIV see ibid., vol.8, no.5, p.34 (1992). The effects of X-ray irradiation during partial discharge measurements are discussed. The partial discharge phenomena in cavities is detailed. A full-scale system capable of testing 138-kV-class post insulators under combined electric stress and X-ray radiation was imple…
The distribution, cytological organization and differentiation of non-articulated laticifers in the primary and mature tissues of Calotropis gigantea (Linn.) R.Br., were studied by the use of optical and electron microscopy. Laticifers occur in the cortex, vascular bundle and pith of the plant axis. At the earliest de…
Diffraction gratings are known to exhibit anomalous behavior at certain critical wavelengths or incident angles. These traditional anomalies manifest themselves as abrupt variations in diffracted order efficiency or grating absorption, while their angular position remains unchanged as predicted by the grating equation…
Poly(methy1 acrylate) was grafted onto chitin in an aqueous medium by using the ceric ion as a redox initiator in the presence of 10−4 M nitric acid and oxygen from the atmosphere. The grafting percentage turned out to be dependent on reaction temperature, time, and initiator concentration, but it was found to be inde…
Sidewall films can be formed during etching by redeposition of etch products and sputtered material from the bottom of the etched structure, by deposition of material sputtered from the mask edge, or by deposition of material from the plasma space. For each process the geometrical characteristics are calculated. A dis…
F-actin purified from rabbit skeletal muscle undergoes reversible dissociation when subjected to hydrostatic pressures up to 240 MPa. Dissociation and reversibility were detected by the following procedures: fluorescence spectral changes observed under pressure, when either intrinsic tryptophan or pyrenyl emission of…
For the purpose of calculating the reflectivity of perfect crystals in the Bragg case, taking into account both normal and Borrmann absorption, it is suggested that its original form is used expressed in terms of complex variables. Care is required regarding the phase angle for the algebraic expression of the square r…
We demonstrate that x-ray reflectivity data covering eight decades of intensity can be obtained from a rotating anode source. Our moderate resolution configuration uses a bent graphite monochromator in contrast to the usual high resolution measurement which uses a silicon or germanium monochromator. Illustrative data…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMorphological variations in polymer blends made in electric fieldsGanesh Venugopal, Sonja Krause, and Gary E. WnekCite this: Chem. Mater. 1992, 4, 6, 1334–1343Publication Date (Print):November 1, 1992Publication History Published online1 May 2002Published inissue 1 November…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEquilibration between the fluorescent and zwitterionic phantom states in alkyl-substituted tetraphenylethylenesJangseok Ma and Matthew B. ZimmtCite this: J. Am. Chem. Soc. 1992, 114, 24, 9723–9724Publication Date (Print):November 1, 1992Publication History Published online1…
Abstract Polyamide‐6 (PA‐6) and sulfonated polystyrene (SPS) interact strongly in solution. Thus, solution blends of PA‐6 and SPS (sulfonation levels from 0 to 12.3 mol%) in m ‐cresol form clear, hazy, or gelled solutions–depending on the ratio of amide (A) to sulfonic acid (S) groups (A/S). NMR studies show that the…
Abstract Foam extrusion of a series of dynamically vulcanized polypropylene (PP)/ethylene-propylene-diene terpolymer (EPDM) blends (commercially available Santoprene) by using chemical blowing agents have been studied. Results suggest that foaming occurs only within the thermoplastic phase and for each composition the…
Measurements of spin-resolved elastic electron-sodium scattering have been carried out at incident energies of 4.1 and 12.1 eV, and the ratio of triplet to singlet scattering cross sections has been obtained at each energy. The ratio is used to provide a determination of not only the magnitudes of the triplet and sing…
We present analytic calculations of minor hysteresis loops obtained when a sample is subjected to a time-varying field B(t)=${\mathit{B}}_{\mathrm{dc}}$+${\mathit{B}}_{\mathrm{ac}}$ cos\ensuremath{\omega}t. We enumerate eight classes of minor hysteresis loops, and calculations are done within the critical-state model…
Semicrystalline structures involving molecular packing and optimized chain conformations of three polyimides have been obtained with the charmm molecular-dynamics program, and their densities calculated. An eclipsed conformation of face-to-face stacking of polymer chains with a relative shift is observed, and the shif…