Materials Literature
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Time-resolved photoluminescence (PL) spectra are reported for gas-suspended 1–10 nm diameter SiOx particles formed by laser ablation of Si into 1–10 Torr He and Ar. Three spectral bands (1.8, 2.5 and 3.2 eV) similar to PL from oxidized porous silicon were measured, but with a pronounced vibronic structure. Particle si…
We report on the synthesis of size-classified PbS nanocrystals by differential mobility analysis of a polydisperse aerosol formed by nucleation and aggregation processes in a furnace reactor. The sublimation temperature employed is below the stoichiometric evaporation temperature, thus enabling direct and simple synth…
General properties of nucleation of elastic defects in crystals undergoing a phase transition are described in the framework of a Landau-type approach. For static defects the phase diagram topology of a nucleus is shown to be independent of the nature and geometry of the defects and may contain additional phases which…
We have measured the dielectric loss in SrTiO3 thin films grown on SrRuO3 electrode layers with thickness ranging from 25 nm to 2.5 μm. The loss depends strongly on the thickness but differently above and below T≈80 K: as the thickness increases, the loss decreases at high temperatures but becomes higher at low temper…
We report Mn $K$-edge extended x-ray absorption fine structure spectra on ${\mathrm{La}}_{0.75}{\mathrm{Ca}}_{0.25}{\mathrm{MnO}}_{3}$ up to high momentum transfer across the metal-insulator $(M\ensuremath{-}I)$ transition. The data show compelling evidence for (i) large or intermediate Jahn-Teller polarons (IJTP), ch…
We report the results of magnetic measurements on a powder sample of NiCu(pba)(D_2O)_3 \cdot 2D_2O$ (pba=1,3-propylenebis(oxamato)) which is one of the prototypical examples of an $S$=1/2 and 1 ferrimagnetic chain. Susceptibility($χ$) shows a monotonous increase with decreasing temperature (T) and reaches a maximum at…
We have carried out angle resolved photoemission spectroscopy of ${\mathrm{SmTe}}_{3}$, a quasi-two-dimensional material with an incommensurate high-temperature charge density wave (CDW). This is the first direct experimental view of the full detail of an imperfectly nested Fermi surface, and the momentum space gap an…
Ab initio Perturbed Ion cluster-in-the-lattice calculations of the impurity centers NaI:Tl+ and CsI:Tl+ are pressented. We study several active clusters of increasing complexity and show that the lattice relaxation around the Tl+ impurity implies the concerted movement of several shells of neighbors. The results also…
Cu-, Eu-, or Mn-doped ZnS nanocrystalline phosphors were prepared at room temperature using a chemical synthesis method. Transmission electron microscopy observation shows that the size of the ZnS clusters is in the 3–18 nm range. New luminescence characteristics such as strong and stable visible-light emissions with…
A sample of poly(vinyl chloride) (PVC) and a polar plasticizer consisting of dioctylphthalate (DOP) and triisopropylphenylphosphate (TIPPP) was prepared and found to possess some electrical conductivity. Different samples of PVC compositions were formulated from the PVC-DOP-TIPPP system and also variable proportions o…
Novel pressure-induced intercalation of alcohols into a layered titanate has been discovered using a diamond-anvil cell and in situ X-ray diffraction measurement. The lepidocrocite(γ-FeOOH)-type titanate containing pentylammonium ions exhibited uniaxial expansion of 0.27 nm in methanol at 1 GPa and 0.23 nm in ethanol…
The intercelluar diffusion of poly(butyl methacrylate) (PBMA; glass transition temperature ( T g ) = 21 °C) at 60 °C was monitored by fluorescence energy transfer in films formed from blends of PBMA latex and a high- T g (hard) latex. Two types of hard latexes were used in blends: one composed of poly(methyl methacryl…
A modified mathematical model based on the melting and recrystallization of an initial distribution of melting temperatures satisfactorily predicts the melting behavior of PET in differential scanning calorimetry. The simulated DSC curves produced in this work agreed fairly well not only with experimental DSC curves p…
Scanning transmission X-ray microscopy (STXM), atomic force microscopy (AFM), and dynamic secondary ion mass spectrometry (DSIMS) were used to obtain the true three-dimensional concentration profiles of polystyrene (PS) and bromo−polystyrene (PBr x = 0 .79 S where x = fraction of monomers brominated) blend films as a…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTAdsorption of Benzene and Ethanol on MCM-41 MaterialC. Nguyen, C. G. Sonwane, S. K. Bhatia, and D. D DoView Author Information Chemical Engineering Department University of Queensland, Brisbane, QLD 4072, Australia Cite this: Langmuir 1998, 14, 17, 4950–4952Publication Date (We…
The accelerated degradation of aqueous polyacrylamide at low temperature was studied. The selected degradation agents included several peroxides, such as potassium persulfate (K2S2O8), ammonium persulfate ((NH4)2S2O8), hydrogen peroxide (H2O2), and the potassium persulfate–sodium thiosulfate (K2S2O8–Na2S2O3) redox sys…
A systematic electrical and mechanical study was carried out on styrene butadiene rubber (SBR), as a nonpolar rubber, and nitrile rubber (NBR), as a polar one blended with pure and waste polyethylene (PE), low and high density. The compatibility investigations, which were carried out by the dielectric method and confi…
Fluorescence optical microscopy (FOM) of poly(vinyl alcohol) (PVA) and poly(vinyl acetate) (PVAc) blends in compositions 9/1, 1/1, and 1/9 (w/w) show that these blends present phase separation in the solid state. Each domain of the solid samples was identified by FOM as PVA-richer domains by green fluorescence of fluo…
The adsorption equilibria for benzene and toluene vapors on commercially available activated carbon fiber were measured by a static volumetric technique. The equilibrium measurements were made at 298.15, 323.15, and 348.15 K and pressures up to 8.7 kPa for benzene and 3.4 kPa for toluene, respectively. The results wer…
A negative-working photoresist based on calix[4]resorcinarene (C-4-RA), 4,4‘-methylenebis[2,6-bis(hydroxymethyl)phenol] (MBHP) as a cross-linker, and a photoacid generator diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS) has been developed. A clear transparent film was obtained from a 25 wt % C-4-RA soluti…