Materials Literature
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Hypericin and stentorin are the most important representatives of the phenanthroperylene quinones. Their tautomerism, dissociation, conformation, and association equilibria make them structurally complex, and they are interesting on the one hand for medical applications (for example, photodynamic therapy) and on the o…
A survey is presented of current investigations of the impact of band structure effects on various aspects of the interaction of charged particles with real solids. The role that interband transitions play in the decay mechanism of bulk plasmons is addressed, and results for plasmon linewidths in Al and Si are discuss…
We study the statistical properties of the scattering matrix S(q|k) for the problem of the scattering of light from a randomly rough one-dimensional surface, defined by the equation $x_3 = \zx$, where the surface profile function $\zx$ constitutes a zero-mean, stationary, Gaussian random process, through the effects o…
Polyansidine organic conductor, was chemically synthesized, via the chemical oxidation of ansidine by persulfate anion in aqueous solution . The prepared polymer was characterized by different methods of analysis such as: thermogravimetric analysis, electric conductivity, infrared and UV—visible absorption spectroscop…
The role of hindered amine light stabilizers (HALS) in the protection of polyolefins continues to expand. HALS are essential components in formulations developed for outdoor use and have been proven to be effective thermo-oxidative stabilizers. The physicochemical properties of hindered amines have a profound effect o…
The influence of convection on the morphology of primary dendrites and on the distribution of germanium in primary crystals of hypoeutectic Ag–Ge alloy was studied. The experiment in microgravity provided conditions for the suppression of melt flow. Both the morphology of the primary dendrites and their chemical compo…
The red luminescence at 686 nm in KTaO3 is investigated in pure as-grown and doped (Al, Ba, Cr, Fe, Er, Li, Mg, Ni, Rh, V, Zr) crystals from different growth laboratories. In contrast to earlier results [1,2] which led to the conclusion that the main center should be an intrinsic defect Ta3+ + O2- vacancy, we found th…
Dark opaque blue to transmissive light blue is the color transition that poly(3,4-propylenedioxythiophene) (PProDOT) and derivatives undergo when switched from their reduced to oxidized state. These polymers are very promising electrochromic materials—they exhibit more rapid switching, lower oxidation potentials, and…
Current voltage (I–V) characteristics have been studied at various temperatures in amorphous thin films of Ge22Se78−xBix and GexSe80−xTe20 where 0≤x≤10. At low electric fields, ohmic behaviour is observed. However, at high electric fields (E≡104 V cm−1) the current becomes superohmic. Analysis of the data shows the ex…
Raman spectroscopy was used to investigate Al selectivity in Si‐doped tetramethylammonium hydroxide (TMAH) solutions whose Si dopant concentration covers both Al passivating and Al nonpassivating instances. Raman spectra of the Si doped solutions suggest different dominant ionic silicate species for passivating and no…
The conversion coefficients from photon fluence to ambient dose equivalent, H* (10) and effective doses were calculated for photons up to 10 GeV. A Monte Carlo code EGS4 was used for these calculations and secondary particle transports were considered. The calculated ambient dose equivalents were compared to the calcu…
Fast and temperature-stable emission band at 5.8 EV has been reveadled in a K2SO4 crystal. This emission can be effectively excited by photons of hv > 15 eV and is interpreted as radiative electron transitions between the subbands of a splitted valence band. The threshold of the formation of electron-hole pairs equals…
Electron and neutron irradiation of diamond produces a wide variety of different EPR defect centres. The definitive establishment of the vacancy (neutral and negatively charged), the nearest neighbour di-vacancy (R4/W6) and a nearest neighbour pair of ⟨100⟩ split interstitials (R1) form some starting points, from whic…
Ethylene-propylene-diene terpolymer rubberlnatural rubber blends (EPDM/NR) in different proportions (100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100) reinforced with 20 phr semireinforcing furnace carbon black have been studied. The permittivity ∊' and dielectric loss ∊″ for these samples were determined in the freque…
One-step preparation of composites of alkaline poly(6-hexanelactam) (PCL) with solid lubricants (SL), such as graphite and molybdenum disulfide, is an energy-saving process as additional polymer fusion and melt mixing are not necessary. The initiator/activator system used were: (i) sodium dihydrido-bis(2-methoxyethoxo…
A simple method is reported for preparing gold nanoparticles capped with 3-mercaptopropionic acid(MPA). The capped Au nanoparticles can be isolated as a dark brown solid which can be re-dispersed in sodium hydrate solution. The average size of nanoparticles is 4.9 ± 0.7 nm, determined by HRTEM. The surface plasmon ban…
Photochemical charge transfer excitation of tetra-phenyl(porphyrinato)iron(III) complexes yields tetraphenyl) (porphyrinato)iron(II) which is able to coordinate molecular oxygen under formation of oxo-[tetraphenyl(porphyrinato)]- iron(IV). Based on this photochemical reaction pathway photocatalytic oxygenation of α-pi…
Visible electroluminescence (EL) from n‐type porous silicon (n‐PS) in an electrolyte solution containing was investigated by potential‐sweep and potential‐step methods. Potential sweep measurements showed that both the cathodic current and EL intensity increased and the EL spectra blue‐shifted as the potential became…
Standard periphyton samplers were used to examine the colonization pattern of periphytic algae on an artificial substrate (glass slides) in the Lam Tsuen River, Hong Kong, between October 1995 and August 1996. Changes in the taxonomic composition, species diversity (Shannon-Wiener diversity index), total standing crop…
We demonstrate how the mathematical treatment of the switching current data allows to characterize the variation of the domain structure during fatigue. Investigating PZT/YBCO heterostructures on SrTiO3 and NdGaO3 substrates we propose two different scenarios of fatigue-induced evolution of the domain structure. The e…