Materials Literature
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Giganticine (1), a novel nonprotein amino acid, has been isolated from a methanol extract of the root bark of Calotropis gigantea and its structure established by spectroscopic methods. It exhibited a significant antifeedant activity against nymphs of the desert locust Schistocerca gregaria.
Hybrid materials have been prepared through the sol–gel route from poly(tetraethylene glycol malonate) (PTEGM) and titanium isopropoxide (TIP) in acidic media. The bulk gels were characterised by thermal analysis (TG, DSC and TMA), wide-angle X-ray scattering (WAXS), transmission electron microscopy (TEM) and FTIR. Th…
For the rehabilitation of the degraded and abandoned land in the tropical area, it needs to define the various characteristics of remaining natural forests. This work was done to find out a physical hazard for root elongation of plant at Lambir Hills National Park, Miri, Sarawak, Malaysia, with special reference to so…
There has been extensive work done in recent years on the analysis and synthesis of systems having memoryless, sector bounded nonlinearities and uncertainties. In this paper we take a fundamentally different approach to develop tests of the stability of systems with hysteresis nonlinearities which, in general, have me…
Kraft paper is used extensively in the electricity supply industry for the insulation of HV apparatus, such as transformers, capacitors and cables. Because of the fibrous nature of the paper, many layers are stacked or rolled to obtain the required electric strength. The insulation is thus a combination of cellulose a…
We study the classical electromagnetic enhancement at the excitation wavelength related to surface enhanced Raman scattering (SERS) experimental configurations in the vicinity of random rough metal surfaces possessing self-affine scaling behavior. The scattered electromagnetic intensity is obtained by means of numeric…
A wide range of physical and mechanical properties can be achieved in polymer/polymer blends by variation of such features as the molecular structure of the components, blend composition, morphology, and processing conditions [1–6]. If the two components of a binary blend are completely miscible at the molecular level…
Variable temperature neutron powder diffraction data are used to pinpoint the mechanism of low thermal expansivity in the Nasicon-related material Sr0.5Ti2(PO4)3; this behaviour is contrasted with that of the parent phase NaTi2(PO4)3.
Conventional organic molecules for applications in second-order non-linear optics are donor–acceptor substituted π systems that show only one intense charge-transfer (CT) transition. Thus, only a single element of the second-order polarizability tensor, β, is significant in these one-dimensional systems. The advantage…
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The magnetic properties of the lithium phthalocyanine radical are investigated for the x,α and β crystal structures via electron paramagnetic resonance (EPR). Different magnetic behaviours (susceptibility, line shape) are evidenced in PcLi powders and interpreted in terms of the molecular packing. A Curie–Weiss suscep…
Long lengths (>150 m) of single-mode chalcogenide optical fiber were fabricated by a double crucible technique. Single-mode transmission through 10 m of continuous fiber was demonstrated using an F-center laser at 2.7 /spl mu/m. The optical loss of this fiber was measured by a standard cutback technique using an FTIR…
Atomic force microscopy is used to characterize the nucleation and beginning growth of chromate conversion coating on polished Al 2024‐T3 alloy surfaces. Rapid nucleation occurs at different rates on the Al matrix and on two distinct intermetallic phases. One phase, assigned as a Cu‐Fe‐Mn aluminide, reaches full conve…
Reduction of an acidified solution of Na2MoO4·2H2O by iron powder results in the formation of the title compound [Mo176O16O480(OH)32(H2O)80]; the compound is tyre shaped and consists of sixteen {Mo8} subunits being linked by forty-eight MoO6 octahedra; remarkable features are the size and mass (which is of the order o…
The catalytic activity for the oxidation of isobutane catalyzed by 12-molybdophosphoric acid was much changed by the V 5+ - and Cs + -substitution for Mo 6+ and H +, respectively. The best yield of methacrylic acid was 9.0% and was obtained for the heteropoly catalyst with V and Cs contents of 1 and 2.5, respectively.…
Impressive advances have been made over the last few years in teaching silicon how to emit light. Recently, light-emitting devices (LEDs) made of porous silicon and other forms of nanoscale silicon have been demonstrated with specifications that start to make them attractive for commercial applications. This paper rev…
We investigate the equilibrium morphological properties of a symmetric ABC triblock copolymer in the strong segregation regime. Although a tricontinuous double diamond phase has been experimentally reported within a large region of the phase diagram, we find that neither gyroid nor double diamond cubic phases are stab…
The synthesis and structure of a tetranuclear copper(II) complex of a bis-N,O-bidentate Schiff base is reported; two types of copper(II) centers and the preference for two conformational degrees of freedom in the ligand lead to the unique formation of a novel supramolecular architecture not requiring a preorganized sy…
A series of ionic η5-monocyclopentadienyl–metal compounds possessing p-substituted benzonitrile ligands has been studied by hyper-Rayleigh scattering at the fundamental wavelength of 1.064 µm. Upon systematic variation of the metal ion, the first hyperpolarizability β was found to increase along the sequence Co, Ni, R…
The scope, mechanism and kinetics of the aerobic epoxidation of alkenes with an aldehyde and substituted β-diketonate–transition metal complexes as catalysts were studied. β-Diketonate complexes of nickel(II) proved to be among the best catalysts for this reaction. The epoxidation is not dependent on substrate concent…