Materials Literature
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The oxidation of porous silicon (PS) is an important issue to be considered for a better understanding of the physical and chemical properties of this material in view of its possible application in several technological fields (optoelectronics, optical filters, environmental monitoring, etc.). In this work the quick…
A core-sheath bicomponent fiber is melt-spun by co-extrusion of poly(butylene tereph thalate) (PBT) as the core and poly(butylene succinate-co-L-lactate) (PBSL) as the sheath. The resulting melt-drawn fiber is continuously guided to cold-drawing at 80°C. The core/sheath ratio of the melt-drawn fiber increases with inc…
The N-oxyl mediated donor-acceptor copolymerization of styrene as a donor and the maleimides N-phenylmaleimide (NPI), N-benzylmaleimide (BMI), and N-cyclohexylmaleimide (CMI) as acceptor monomers is studied, using 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) as reversible capping agent and benzoyl peroxide (BPO) as in…
A new one-step method is developed for the formation and separation of a thin porous silicon film (PSF) by electrochemical etching of silicon in hydrofluoric (HF) acid based solution. This provides advantages over the existing techniques, which are requiring multiple-steps for fabrication and separation of a thin laye…
We suggest a definition of the effective ionic charges q*i of different pairs of ions connected in tetrahedral, octahedral and dodecahedral polyhedra in such oxide crystals as spinels, garnets and perovskites. The electronic polarizability αi of cations and the O2— atomic core polarizability are calculated by 〈r2k〉 ac…
Fourier-type spot-array illuminators are designed for electromagnetic fields in the paraxial domain of diffractive optics. An analytical construction of the periodic, spatially variable Jones matrix is presented, which produces 100% conversion efficiency from an arbitrarily polarized incident plane wave into M × N=2 P…
Scope of Deliverables: This section describes the uses of ultrasound in the food industry. A general theory about the mechanism of microbial inactivation is presented. Data from inactivation of food microorganisms are scarce, and most applications of ultrasound involve its use in combination with other preservation me…
X-ray intensities for the “tetragonal almandine-pyrope phase” (TAPP), *(FeMg) VIII (AlMgFe) 4 [ IV (SiAl)O 4 ] 3 where * refers to a capped tetrahedral site, reported by Harris et al. (1997) were recollected using the identical crystal, and the crystal structure was refined from these new data. The basic structure of…
Silicon electrochemistry has many applications, but still a number of unanswered questions. This paper reports on experimental results of current transient measurements and impedance spectroscopy along the I–U curve in the Si–HF system. The points of inflection of the I–U characteristics are found to be interesting, s…
Inorganic siliceous porous materials such as MFI type zeolite, mesoporous silica MCM-41 and silica gel with different average pore diameters were applied to the adsorptive separation of methylaluminoxane (MAO) used as a cocatalyst in α-olefin polymerizations. The separated MAOs combined with rac-ethylene-(bisindenyl)z…
Calcined Mg-Al hydrotalcites (Mg/Al=3) can be used as an efficient catalyst in the selective O-methylation of phenol and catechol and N-monomethylation of aniline employing dimethylcarbonate (DMC) as a methylating agent in vapor phase at 275°C.
Two types of polyurethane (PU) resins were synthesized by polyaddition of isophorone diisocyanate (IPDI), poly (propylene glycols: PPG-750 and PPG-2000), and 2,2-bis(hydroxymethyl)propionic acid (DMPA). Chemical structure of PU was confirmed by 1H and 13C NMR analysis. The PU resins were found to be water-dispersible…
The effects of fabrication parameters on porous silicon morphology have been investigated using small-angle X-ray scattering and gas adsorption methods to understand the dependences of the parameters on each other. The dependence of the specific surface areas on current density was studied using three different electr…
Abstract Diels–Alder reaction between tribenzo[b,g,l]thiopheno[3,4-q]porphyrazine and dimethyl acetylenedicarboxylate at ca. 200 °C produced a substituted tribenzo[b,g,l]porphyrazine and 3:1 unsymmetrically substituted phthalocyanine, which were characterized by UV-VIS, MCD, NMR, and mass spectroscopies.
Results are presented of studies of the 154Sm1−x SrxMnO3 system using neutron powder diffraction and small-angle polarized neutron scattering. An analysis of the neutron diffraction spectra showed that at T < 180 K these exhibit typical Jahn-Teller distortions of the manganese-oxygen octahedrons which persist under fu…
A comparative study of the Hall effect and the longitudinal resistivity of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ $(x=0.30$ and $x=0.67)$ thin films has been performed. The underdoped samples $(x=0.30)$ show a semiconductor-to-quasimetal transition, and a colossal magnetoresistance (CMR)…
A hyperbranched aromatic polyamide has been prepared by direct polycondensation of 5-(4-aminobenzoylamino)isophthalic acid (ABZAIA), using the modified Higashi's method. The resultant polymer is soluble in aprotic polar solvents such as DMF, DMAc, NMP, and DMSO. Intrinsic viscosities of poly(ABZAIA) samples, measured…
In this article we present a low-cost, high-speed, high-accuracy in situ thin film measurement system for real-time process monitoring and industrial process control. This sensor, the two-channel spectroscopic reflectometer (2CSR), is a hybrid of spectroscopic ellipsometry and spectroscopic reflectometry. In 2CSR a po…
The optical and electrical properties of porous silicon microcavities are strongly dependent on the environment. For highly luminescent samples both the luminescence intensity and the peak position are affected by organic substances, which also strongly modify the electrical conductivity, giving the possibility to obt…
An earlier study demonstrated the presence of 11 morphologically distinct demes (‘morphotypes’) within the Diploneis smithii/D. fusca species complex in a single sample from Ganavan near Oban on Scotland's west coast. Two of these demes were subsequently shown to occur elsewhere around the British coastline and to kee…