Materials Literature
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We have studied the frequency and temperature dependences of permittivity and impedance of the compounds ACu3Ti4O12 (A=Ca,Bi2∕3,Y2∕3,La2∕3) in the ranges of 10−1–106Hz and −150–200°C. All compounds investigated display similar dielectric properties. Specifically, they all have a Debye-like relaxation and their dielect…
The quintessence of the hot-injection method, a synthesis route for monodisperse, highly luminescent semiconductor nanocrystals, is reviewed. The separate stages of nucleation and growth of the nanocrystals are discussed in the framework of classical nucleation theory and an equilibrium model proposed by Debye. We als…
Three kinds of Er 3+ -doped tellurite glasses with different hydroxyl groups are prepared by the conventional melt-quenching method. Infrared spectra are measured to estimate the exact content of OH − groups in samples. The maximum phonon energy in glasses are obtained by measuring the Raman scattering spectra. The st…
The crystal structure of the title compound, magnesium pentaoxoditellurate(IV), has been redetermined from a crystal grown from the melt and confirms the previous study [Trömel (1975). Z. Anorg. Allg. Chem. 418, 141–144], but with improved precision. It is isotypic with β-MnTe2O5 and contains MgO6 octahedra and TeO3…
Nichtaromatische stabile Polyene liefert die Dioxygenierung von Oligothiophenen mit in situ aus F2 und wässrigem Acetonitril hergestelltem HOF⋅CH3CN (siehe Schema). Die vollständig S,S-dioxygenierten Derivate haben eine erheblich kleinere HOMO-LUMO-Lücke als die Ausgangsverbindungen und liegen im Festkörper bevorzugt…
Ein photochromer molekularer Schalter kann als Boolesches AND-Gate wirken. Als Eingabe dienen UV-Licht, das zur Photoisomerisierung eines Dihydroindolizins in die offene, dipolare Form führt, und ein elektrisches Feld, das dieses Isomer in Lösung ausrichtet (siehe Schema). Zum Lesen der Ausgabe wird der elektrische Li…
By combining tetrathiafulvalenes (TTFs) and triarylamines, four TTF-triarylamine conjugates bridged by an annulated pyrrole ring were designed and synthesized by an N-arylation reaction. Electrochemical and photophysical investigations suggest that these novel conjugates possess very strong electron-donating ability w…
The reorientation of one small paramagnetic molecule (spin probe) in glassy polystyrene (PS) is studied by high-field electron paramagnetic resonance spectroscopy at two different Larmor frequencies (190 and 285 GHz). Two different regimes separated by a crossover region are evidenced. Below 180 K the rotational times…
We explore the metastability effects across the order-disorder transition pertaining to the peak effect phenomenonon in critical current density $({J}_{c})$ via the first and the third harmonic ac susceptibility measurements in the weakly pinned single crystals of $2H\text{\ensuremath{-}}{\mathrm{NbSe}}_{2}$. An analy…
Herein we demonstrate a unique processing technique for engineering multicomponent ceramic nanopowders with precise morphologies by "nanoblast" calcination/deagglomeration. Multiple "nanoexplosions" of C(3)H(6)N(6)O(6) nanoparticles embedded in preliminary engineered nanoreactors break apart the agglomerates because o…
Very ANDy: A photochromic molecular switch has been found to act as an AND Boolean logic gate. The switch takes as input both UV light, which causes photoisomerization of a dihydroindolizine to an open, dipolar form, and an electric field, which aligns this isomer in solution (see scheme). The output of the gate is re…
Cu 2 O thin films with (111) preferred orientation have been grown on glass and Cu substrates by rapid thermal oxidation of Cu at 500°C for 45 s. The optical band gap energy was determined by spectral data of transmittance and absorbance to be 2.04 eV. The electrical conductivity of grown films was measured around (1.…
Abstract The present review deals with some selected topics pertaining to the theory of OD structures of layers founded by K. Dornberger-Schiff. An attention is paid mainly to the notion of VC (Vicinity Condition) structures and to the position of OD (Order-Disorder) structures within the VC structures. Explained is a…
Sn-doped Ge 2 Sb 2 Te 5 thin films deposited on Si(100)/SiO 2 substrates by rf magnetron sputtering are investigated by a differential scanning calorimeter, x-ray diffraction and sheet resistance measurement. The crystallization temperatures of the 3.58 at.%, 6.92 at.% and 10.04 at.% Sn-doped Ge 2 Sb 2 Te 5 thin films…
Abstract Summary: Syndiotactic polystyrene (sPS)/organophilic clay nanocomposites were obtained by in situ coordination‐insertion polymerization of styrene. Two cationic surfactants (alkylammonium and alkylphosphonium) were used for the intercalation of montmorillonite (MMT). For each organically modified clay, three…
The handedness relationship between adjacent layers in nested double-wall carbon nanotubes (DWNTs) has been investigated for the first time. Our high-resolution electron microscopy analysis on a series of specimen tilts can successfully tell the handedness of each constituent nanotube in a DWNT, and therefore the chir…
Ab initio electron propagator methods are applied to the prediction, assignment, and interpretation of the valence photoelectron spectra of free base porphine and of magnesium and zinc porphyrins. Tests of various approximate self-energies, including the partial third (P3), the outer valence Green's function, and the…
Unsymmetrical benzo[15]crown-5 ethers 5 with one lateral ortho-terphenyl unit bearing alkoxy side chains of varying chain lengths (C5-C14) were prepared from 3,4-dialkoxyphenylbromides 2. Complexation with metal salts MX (M = Na, Cs) afforded the corresponding derivatives MX5. The uncomplexed crown ethers 5 h and 5 i,…
Sorption of carbaryl (1-naphthyl-N-methyl-carbamate) from aqueous suspension to smectite was studied using Fourier transform infrared (FTIR), high-performance liquid chromatography (HPLC) (for batch sorption), and quantum chemical methods. The amount of carbaryl sorbed was strongly dependent on the surface-charge dens…
Crystallographic, magnetic, and NMR properties of a ${\mathrm{Na}}_{x}{\mathrm{CoO}}_{2}$ single crystal with $x\ensuremath{\simeq}1$ are presented. We identify the stoichiometric ${\mathrm{Na}}_{1}{\mathrm{CoO}}_{2}$ phase, which is shown to be a nonmagnetic insulator, as expected for homogeneous planes of ${\mathrm{…