Materials Literature
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We present a joint theoretical and experimental investigation of the electronic and optical properties of vanadium pentoxide. Electron energy-loss spectroscopy in transmission was employed to measure the momentum-dependent loss function. This in turn was used to derive the optical conductivity, which is compared to th…
Äußerst stabil sind die selenverbrückten Goldkomplexe [Au10Se4(dppm)4]Br2 und [Au18Se8(dppe)6]Cl2, die durch Umsetzung von Gold-Phosphan-Komplexen [(AuX)2(Ph2P(CH2)nPPh2)] (X=Halogen; n=1, 2) mit silylierten Selenverbindungen erhalten wurden. Mittels Elektrospray-Ionisation gelang es, das Kation [Au18Se8(dppe)6]2+ (St…
Tin–oxide (SnO2) thin films were prepared by a modified spray technique called electrostatic spray pyrolysis. Their electrical and optical properties dependence on fluorine concentration, substrate temperature Ts, and the substrate–nozzle distance Dsn was studied. Dsn and Ts seem to be interrelated for the optimizatio…
Microsegregation and a flat, radial conformation of the polar core region are responsible for the columnar mesophases formed by the non-anisometric sixfold alkoxy-substituted 2,4,6-triarylamino-1,3,5-triazines (1). Charge-transfer interactions with flat acceptor molecules such as 2,4,7-trinitrofluoren-9-one impose a l…
The Tb(Fe0.55Co0.45)1.5 films were fabricated by rf magnetron sputtering from a composite target. Samples were investigated by means of x-ray diffraction, vibrating sample magnetometer, conversion electron Mössbauer spectra, and magnetostriction measurements. The as-deposited film is an amorphous alloy with a perpendi…
Scanning tunneling microscopy (STM) images of carbon nanotubes grown by the catalytic cracking of hydrocarbons, which exhibit a well-defined axial periodicity in the 1 nm range, are reported. The data are interpreted as tightly wound, single-wall, coiled carbon nanotubes with an interspire distance of 0.34 nm as the d…
This article reports a study on the dielectric relaxation processes of Cd2Nb2O7 compound. Three dielectric relaxation modes I, II, and III were reexamined. By using the Cole–Cole equation fitting of the frequency dependence of dielectric constant and loss, we obtained more precise relaxation time data, compared to the…
The interaction between polyacrylic acid and two water-soluble cellulose ethers (methylcellulose and hydroxyethylcellulose) was studied. Viscometry, velocity sedimentation, small-angle neutron scattering, and potentiometric titration methods show the formation of stable water-soluble interpolymer complexes due to hydr…
Magnetic characterization has been performed on the cubic phases λ-Li0.07Mn2O4, Li0.98Mn2O4, and the tetragonal phase Li1.82Mn2O4, prepared by electrochemical cycling of a single starting LiMn2O4 spinel. The magnitude of the negative Weiss constant increases with x in LixMn2O4, indicating that antiferromagnetic intera…
The dynamical-mean-field theory combined with the noncrossing approximation is used to set up a scheme to study the electronic structure of strongly correlated electron systems. The noninteracting band structure is obtained from a density-functional calculation within the local-density approximation. With this method…
The dynamic mechanical properties of an organic hybrid consisting of chlorinated polyethylene (CPE) and N,N-dicyclohexyl-2-benzothiazolyl sulfenamide (DZ) were investigated. All the CPE/DZ hybrids showed a single loss tangent (tan δ) peak in the mechanical spectra. The peak area under the tan δ/temperature curves arou…
Immer größere expandierte Porphyrinoide (ein Beispiel ist gezeigt) werden durch neue Synthesemethoden zugänglich. Diese nichtaromatischen Verbindungen enthalten bis zu 16 konjugierte Pyrrolringe, zeigen eine neuartige Metallkoordination, sind chiral und können Anionen binden.
We have studied the quasibinary ferromagnetic semiconductor (Ga0.98Mn0.02)As by magnetic circular dichroism in x-ray absorption. We find a richly structured Mn absorption spectrum typical for localized 3d electrons. An analysis of the magnetization-averaged and dichroism line shapes shows a local Mn moment of 4.6μB, w…
We report computer simulation results of free energies of proton-disordered hexagonal ice and liquid water at atmospheric pressure with the 4-site transferable intermolecular potential model of water. A new reference system is used to calculate the free energy of the ice phase. The melting point of proton-disordered h…
Low-coverage adsorption isotherms for ${\mathrm{CH}}_{4}$ on single-walled carbon nanotube bundles have been measured at eight temperatures between 155 and 195 K. The nanotubes used in this study were untreated, so that the tubes have closed ends. The isosteric heat of adsorption was determined from the isotherms and,…
NdSc 3 ( BO 3 ) 4 (NdSB) can be grown as a nonlinear optical crystal having hexagonal (huntite) structure. The crystal has important spectroscopic properties suitable for various applications in photonics. The observed crystal-field splitting of the energy levels of Nd3+(4f3) has been identified based on analyses of t…
We have experimentally studied the mechanism of reentrant metal-insulator-metal transition of DCNQI-Cu system. Measurements of specific heat and latent heat were carried out by thermal relaxation (0.5< T <40 K), adiabatic pulse (20< T <100 K) and Differential Thermal Analysis (DTA) methods on samples under various che…
Verbrückende Methylengruppen werden in terminale Methylgruppen überführt, wenn periodisch mesoporöse Methylensilicate, die erstmals durch Tensid-Templat-Synthese hergestellt wurden, unter kontrollierten Bedingungen (350–600°C) getempert werden. Die Methylengruppen, die zunächst Bestandteil der Kanalwände sind, werden…
Two emission bands were simultaneously observed in iron-passivated porous silicon and their peak energies were in good agreement with the first two gap energies calculated for silicon nanocrystallites $(nc\ensuremath{-}\mathrm{Si}).$ This result indicates the existence of separate conduction subbands caused by the qua…
We have developed a calculational method for ligand-field multiplets. In our method the effect of the perturbations surrounding the considered atom is described by a monoelectronic potential interacting with the external electrons and the Hamiltonian is obtained by summing all the intra-atomic interactions and the ext…