Materials Literature
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We present infrared and Raman measurements of magnetite $({\mathrm{Fe}}_{3}{\mathrm{O}}_{4}).$ This material is known to undergo a metal-insulator and a structural transition (Verwey transition) at ${T}_{V}=120$ K. The structural aspect of the Verwey transition is disclosed by the appearance of additional infrared-act…
Synthesis of a guest-free clathrate form of crystalline silicon was achieved by successive vacuum treatment and density separation of ${\mathrm{Na}}_{x}{\mathrm{Si}}_{136}$-based materials. The new allotrope of silicon has an open framework structure based upon slightly distorted tetrahedral atoms bound into five- and…
Dispersions of hydrophilic fumed silica are investigated in a range of polar organic media. The silica forms stable, low-viscosity sols exhibiting shear thickening behavior in a host of liquids, including ethylene glycol and its oligomers and short-chain alcohols, such as n -propanol. In contrast, the silica flocculat…
We study theoretically the thermopower in cobalt oxides generalizing the Heikes formula. In the oxides, states of carriers are largely degenerate because the crystalline field and Hund's rule coupling compete in cobalt ions. It is shown that the degeneracy, together with strong correlation of $3d$ electrons, causes th…
The field of viscous liquid and glassy solid dynamics is reviewed by a process of posing the key questions that need to be answered, and then providing the best answers available to the authors and their advisors at this time. The subject is divided into four parts, three of them dealing with behavior in different dom…
We present an atomistic simulation method for calculating the defect formation free energy and defect volume using lattice dynamics. The periodic simulation methods have been extended to allow charged systems with subtraction of defect-defect interactions to be studied routinely. This allows constant pressure minimiza…
We report resonance Raman spectrum of the triphenylene radical cation generated by γ-irradiation in a Freon glass at 77 K. Raman spectra were obtained using excitation in resonance with the strong cation absorption band near 400 nm. Ab initio calculations (Hartree−Fock, B-LYP, and B3-LYP, all with 6-31G basis set) wer…
Dynamic CD and 1 H NMR spectroscopies have been applied for studying the phenomenon of chirality inversion in the supramolecular system consisting of bis(Zn porphyrin) and ( R )-amine upon stepwise titration with ( S )-amine. The initially induced CD signals corresponding to the coupled B transitions of bis(Zn porphyr…
The 13.5 kDa N-terminal part of the propeptide remains associated with mature cathepsin C after proteolytic activation and excision of the activation peptide. This residual pro-part, isolated from the recombinant enzyme, folds spontaneously and rapidly to a stable, compact monomer with secondary structure and stable t…
The polarized optical absorption (OA) and photoluminescence of Pr 3+ doped KGd(WO 4 ) 2 (KGW) single crystals have been measured at selected temperatures between 7 and 300 K. For the studied Pr concentrations, [Pr] = 0.03 × 10 20 -1.9 × 10 20 cm -3 , a unique site is observed. 74 energy levels were experimentally dete…
We fabricated a robust ultrathin film of a triblock copolymer, poly[styrene- b -(ethylene- co -butylene)- b -styrene] (SEBS), functionalized with 2% of maleic anhydride by melt/solution grafting to a chemically reactive silicon surface. We used epoxy-terminated self-assembling monolayers to functionalize silicon surfa…
Whereas correlation of physical process parameters with bacterial reduction is well established in thermal sterilisation, such a method is currently neither generally recognised nor possible for H2O2 decontamination. As a result, the efficiency and reproducibility of H2O2 decontamination and the course of the process…
A Raman spectrum consistent with that expected from an Al2OF6(2-) ion was observed when Na2O was dissolved in a eutectic LiF/NaF/KF (FLINAK) melt at 500 degrees C, which contained a low concentration of either AlF3 or Na3AlF6. Furthermore, it was possible to trap the Al2OF6(2-) ion in the frozen solid and to measure i…
We report a study of simple ABO 3 type perovskites BaTiO 3 , PbTiO 3 , KNbO 3 , SrTiO 3 and the relaxor perovskites PbSc 1/2 Nb 1/2 O 3 (PSN) in their cubic phase using hard synchrotron radiation and hot neutrons. Gram-Charlier expansions of the thermal parameters have been performed and have revealed interesting feat…
A performance assessment of the corrugated pore structure model (CPSM), developed in part 1 ( Ind. Eng. Chem. Res. 2000, 39, 3747), is carried out through a simulation of experimental gas sorption hysteresis, covering all IUPAC versions and that of the novel MCM-41 materials. The materials studied are an anodic alumin…
The lanthanide−transition-metal complex (H 2 O) 6 (DMF) 6 Ho 2 [Ni(CN) 4 ] 3, 1, was prepared from the reaction of Ho(NO 3 ) 3 ·6.5H 2 O with K 2 [Ni(CN) 4 ] at a 2:3 molar ratio in DMF (DMF = N, N -dimethylformamide). This compound is a model compound for studying the effects of H 2 O ligands on the coordination geom…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTControlled Cationic Ring-Opening Polymerization of MonothiocarbonateNobukatsu Nemoto, Fumio Sanda, and Takeshi EndoView Author Information Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku,…
Recent investigations have implicated cagelike precursors in the unusually high gelation conversion (∼82%) of acid-catalyzed tetraethoxysilane. However, the statistical models used so far cannot capture kinetic or composition-dependent features of alkoxysilane polycondensation. Here we take a first step toward unified…
A brief review of the application of calorimetry to measurement of the kinetics of slow processes is presented. Processes degrading or otherwise changing the properties of materials often occur too slowly to be readily measured by conventional chemical analyses but can be measured in a relatively short period of time…
The new compounds [NBu 4 ][Cu(CN)X] (X = Br ( 1 ), I ( 2 )) and [NBu 4 ][Cu 3 (CN) 4 ]·CH 3 CN ( 3 ) have been prepared by reaction of [NBu 4 ]X with CuCN in acetone ( 1, 2 ) or acetonitrile ( 3 ), and have been characterized by X-ray crystallography and vibrational spectroscopy. Compounds 1 (C 34 H 72 Br 2 Cu 2 N 4,…