Materials Literature
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The evolution of the optical phonon spectra of colloidal core/shell CdSe/ZnS quantum dots with an increase of the shell thickness from 0.5 to 3.4 monolayers has been studied by resonant Raman spectroscopy. The results obtained suggest that the ZnS shell changes its structure from amorphous to partly crystalline as the…
The galvanic replacement reaction between Ag nanoparticles and an aqueous HAuCl 4 solution has recently been demonstrated as a simple and convenient route to metal nanostructures with hollow interiors and highly crystalline walls (see, for example, Sun, Y.; Mayers, B. T.; Xia, Y. Nano Lett. 2002, 2, 481. Sun, Y.; Xia,…
A glowing response: Novel fluoride-selective sensors, utilizing fluoride-induced lactonization to highly fluorescent coumarin derivatives, are reported. The incorporation of this sensory system into a conjugated polymer amplifies the fluorescence response which can be detected visually, see scheme; TIPS=triisopropylsi…
We discuss dissipative particle dynamics as a thermostat to molecular dynamics, and highlight some of its virtues: (i) universal applicability irrespective of the interatomic potential; (ii) correct and unscreened reproduction of hydrodynamic correlations; (iii) stabilization of the numerical integration of the equati…
Different kinds of hemicellulose-based hydrogels have been made by radical polymerization using hydrosoluble hemicellulose from spruce chips with a number-average molecular weight and polydispersity of 2400 and 1.5 respectively. 80% of the hemicellulose was galactoglucomannan and the remainder mainly 4- O -methylglucu…
A review of our work with spectral fitting of CP/MAS 13 CNMR spectra recorded on isolated cellulose I, on a mixtures of cellulose I and xylan and, on kraft pulps is given. The conceptual model for cellulose I used by us is presented. References demonstrating the validity of the spectral fitting model is given. Results…
The self-assembly behavior of a series of fluorinated cellulose ester copolymers with different F-substituents and with varying cellulose propionate (CP) molecular weight, and that of several xylan-rich hetero-polysaccharides and their derivatives, were examined in relation to their critical micelle concentration (CMC…
Silicon nanoparticles have been fabricated in both oxide and nitride matrices by using plasma-enhanced chemical vapour deposition, for which a low substrate temperature down to 50 °C turns out to be most favourable. High-rate deposition onto such a cold substrate results in the formation of nanoscaled silicon particle…
Layer-by-layer (LBL) films of chitosan alternated with an azopolymer, PS119, have been used for optical storage and fabrication of surface-relief gratings. The optical properties stem from the trans-cis-trans isomerization cycles undergone by the azochromophore, with a kinetics for writing the birefringence pattern th…
Oat spelts contain high amounts of xylan whereas the lignin content is comparatively low. Accordingly this raw material is an interesting candidate for the isolation of xylan. The variation in chemical composition of oat spelts from different sources was investigated. Xylans were isolated by alkaline extraction under…
Sol-gel films on austenitic stainless steel (AISI 316L) polished wafer were prepared from sono-sols obtained from tetraethylorthosilane and hydrated calcium nitrate. However, pitting was observed in different places on the stainless steel surfaces. The corrosion resistance was evaluated by the polarization resistance…
We report investigation of non-linear electronic transport through artificial grain-boundary junctions made on epitaxial films of ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ on bicrystal ${\mathrm{SrTiO}}_{3}$ substrates. The experiments carried out over the temperature range 4.2 K--300 K in magnetic fi…
Knowing the dielectric functions of semiconductor nanocrystals isolated in a dielectric matrix is important to both solid-state physics and applications. In this work, we have developed an approach to determine the dielectric function of Si nanocrystals embedded in a ${\mathrm{SiO}}_{2}$ matrix synthesized with Si ion…
The thickness of (110) and (200) sectors in truncated single crystals of linear polyethylene grown from dilute n -octane solution at 95 °C was measured by atomic force microscopy (AFM) in tapping mode. The (110) sector was found to be 1.1 nm thicker than the (200) sector. This can be explained by a somewhat smaller ti…
We report on the acoustic attenuation in an AlPdMn icosahedral quasicrystal between 15 and 300 K, in the tens of GHz range. High frequency coherent longitudinal acoustic waves are excited and detected by an optical ``pump and probe'' technique, in an interferometric configuration. Our results reveal that, at high temp…
Dielectric behavior and phase transitions of [001] oriented $(1\ensuremath{-}x)\mathrm{Pb}({\mathrm{Mg}}_{1/3}{\mathrm{Nb}}_{2/3}){\mathrm{O}}_{3}\ensuremath{-}x{\mathrm{PbTiO}}_{3}$ single crystals with $x=29,$ 31, 32, and 33 % were investigated by impedance measurements and high resolution x-ray diffraction analysis…
Electron-tunneling spectroscopy on ${\mathrm{MgCNi}}_{3}$ has been studied with $N/{\mathrm{MgCNi}}_{3}$ point contacts with $N=\mathrm{PtIr}$ and Au. Most of the measured tunneling conductance show an Andreev reflection peak and a pronounced dip structure outside the peak. We introduce a Josephson junction in series…
Typical functionalization reactions of xylan are reviewed. Moreover, comments about the analytical characterization of the xylan derivatives are given and some structure-property relationships are discussed
The properties of hemicelluloses and especially their softening are important for the performance of paper products; softening temperatures of hemicelluloses have earlier been determined under various conditions. However, there is a lack of mechanical spectroscopic data needed for characterizing their behavior in prod…
Every cloud has a silver lining. The use of poly(styrene sulfonate)/poly(allylamine hydrochloride) (PSS/PAH) polyelectrolyte capsules as microreactors is described for the photochemical synthesis of nanosized silver particles, exclusively, inside a restricted volume of capsule (see graphic). The formed Ag nanoparticle…