Materials Literature
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The procedure of five consecutive recycling steps by injection moulding of postconsumer PET was evaluated on the basis of processing and drying parameters. The equations that govern the increase in sample mass of the polymer while in contact with the atmosphere were obtained on the basis of weight variation measuremen…
The imidization and phenylethynyl end-group reaction behavior of phenylethynyl-terminated imide oligomers (LaRC™ PETI-5) with a number-average molecular weight of 2500 g/mol has been extensively interpreted in terms of the disappearance and appearance of several characteristic absorption peaks. Most characteristic FTI…
The influence of the chemical structures of the polyamides on chlorine resistance was studied by measuring their chlorine uptake rates. They were prepared from isophthaloyl dichloride and aliphatic, cycloaliphatic, or aromatic diamines by the solution or interfacial polycondensation method. This study showed that the…
The presence of low molecular weight lactic acid derivatives in films enhanced the degradability of polylactide in a biotic medium. Two different biotic and abiotic series were investigated. The films used for the first abiotic and biotic series (a-1 and b-1 films) initially contained some lactic acid and lactoyl lact…
Phase equilibrium in confined Ising antiferromagnets was studied as a function of the coupling (v) and a magnetic field (h) at the surfaces, in the presence of an external field H. The ground state properties were calculated exactly for symmetric boundary conditions and nearest-neighbor interactions, and a full zero-t…
We propose the Landau model for lock-in phase transitions in uniaxially modulated improper ferroelectric incommensurate-commensurate systems of class I. It includes Umklapp terms of third and fourth order and secondary order parameter representing the local polarization. The corresponding phase diagram has the structu…
The alpha-helix is a key structural element in a wide range of peptides and proteins. We report here the design, synthesis, and characterization of a modified peptide in which the helix content can be reversibly photoregulated. The peptide contains two cysteine residues that are cross-linked by an azobenzene derivativ…
Nanocomposites with different concentrations of nanofiller were prepared by adding nanosilica filler to the single-phase polyurethane matrix. A control series was prepared with the same concentrations of micron-size silica. The nanosilica filler was amorphous, giving composites with the polyurethane that were transpar…
The first cumulant Ω( k ) of the dynamic structure factor as a function of the magnitude k of the scattering vector was determined from dynamic light scattering measurements for three poly( n -hexyl isocyanate) (PHIC) samples with weight-average molecular weights equal to 1.04 × 10 5, 3.63 × 10 5, and 7.71 × 10 5 in n…
We report laser-induced phase transitions in CdS nanocrystals under radiation of 7 ns laser pulses with a wavelength of 532 nm. The observed change in size distribution of the nanocrystals, as well as the change of their crystal structure from orthorombic to cubic, are uncovered by high-resolution transmission electro…
The 1.54 μm Er3+ photoluminescence excitation (PLE) and photoluminescence (PL) spectra of erbium-doped silicon-rich silicon oxide (SRSO) are investigated. Between 350 and 820 nm, PLE spectra are broad and featureless, and the PL spectra are independent of the excitation wavelengths. The results indicate that in erbium…
We have investigated the local free volume and its thermal fluctuation in an amorphous polymethylsilsesquioxane (PMSQ) consisting only of T 3 (CH 3 SiO 3/2 ) and T 2 (CH 3 Si(OH)O 2/2 ) units using photoisomerization of azobenzene molecularly dispersed in the PMSQ films as a photoprobe over a wide temperature range (4…
A weakly nonlinear analysis is employed to investigate the onset of plume convection in the mushy layer of a binary solution directionally solidified from below. An improved mathematical model including the constant pressure condition at the melt/mush interface is applied to analytically analyse the nonlinear behaviou…
Electrical resistance measurements have been made on high-purity, type-IIa diamonds which had been implanted with carbon ions at liquid-nitrogen temperature followed by rapid thermal annealing to 500 °C. The initial damage density was estimated by appropriate computer simulation to exceed the equivalent damage of 1022…
The carbon ion energy used during filtered cathodic vacuum arc deposition determines the bonding topologies of amorphous-carbon (a-C) films. Regions of relatively low density occur near the substrate/film and film/surface interfaces; their thicknesses increase with deposition energy. The ion subplantation growth resul…
Room-temperature photoinduced, selective-area deposition of gold films on polyimide from gold salt solution using synchrotron radiation x rays is described. A film growth rate as high as 40 nm/min is obtained. For thickness <50 nm, the films consist of nanograins with a grain size of about 200 nm. For thicker f…
We report here the bulge testing results of both dense and porous poly-arylethers (PAE) polymeric low dielectric constant thin films. These films were prepared on a 4.7-μm-thick Si membrane window of 1600×1600 μm2. The Si membrane was subsequently removed in a pulsed XeF2 etcher and the remaining thin film became the…
Thin layers of PuSb and PuSe were studied by photoelectron spectroscopy. X-ray photoelectron spectroscopy and high-resolution valence-band ultraviolet photoelectron spectroscopy spectra show localization of the 5f states and a low density of states at E(F) in PuSb. In PuSe, which can be classified as a heavy fermion s…
Equilibrium conductivity fluctuations of mesoscopic domains are found in film and bulk single-crystal manganite colossal magnetoresistive material. Temperature and field dependences of the Boltzmann factors for a collection of two-state fluctuators give measures of the magnetic moment and entropy differences between t…
New fabrication method of nanoscale regular tips for vacuum microelectronics basing on electrochemical anodizing double- layer systems aluminum-niobium in aqueous acid electrolyte has been developed. This method allows providing very small overall emitted size and high uniform packaging densities without lithography a…