Materials Literature
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A review is presented of the debates between the present authors and other investigators regarding the possible role of diffusional creep in the plastic flow of polycrystalline metals at low stresses. These debates are recorded in eleven papers over the past seventeen years. ln these papers it has been shown that the…
The electron-density distribution in hydrated and dehydrated sodium-type zeolite LTA was visualized from X-ray powder diffraction data by combining Rietveld analysis and a maximum-entropy method. The X-ray diffraction data were analyzed on the basis of the composition Na 95 Si 97 Al 95 O 384 and a structural model (sp…
Calcined hydrotalcite-like compounds (HTlcs) can be reconstructed to their original structure by exposure to an aqueous solution, provided that the original HTlcs contain volatile interlayer anions. In the present study, repetitive treatment consisting of calcination at 400 °C and subsequent reconstruction in an aqueo…
Prior manual work has shown that the condensation of mesitaldehyde and pyrrole leading to tetramesitylporphyrin depends sensitively on concentration and requires cocatalysis involving BF 3 ·O(Et) 2 and ethanol or other protic species. We have applied an automated microscale chemistry workstation capable of parallel or…
We provide a proof that when there is no forcing the recently introduced projective dynamics Monte Carlo algorithm gives the exact lifetime of the metastable state, within statistical uncertainties. We also show numerical evidence illustrating that for slow forcing the approach to the zero-forcing limit is rather rapi…
The conditions under which relaxation dynamics in the presence of quenched-in disorder lead to rate-independent hysteresis are discussed. The calculation of average hysteresis branches is reduced to the solution of the level-crossing problem for the stochastic field describing quenched-in disorder. Closed analytical s…
Three different clusters, Si_9H_12, Si_15H_16, and Si_21H_20, are used in density-functional theory calculations in conjunction with ab initio pseudopotentials to study how the energetics of H_2 dissociativ e adsorption on and associative desorption from Si(001) depends on the cluster size. The results are compared to…
The insulating state of matter is characterized by the excitation spectrum, but also by qualitative features of the electronic ground state. The insulating ground wavefunction in fact: (i) sustains macroscopic polarization, and (ii) is localized. We give a sharp definition of the latter concept, and we show how the tw…
Synthetic diamond crystals grown using a solvent catalyst that contains Ni were studied by optical detection of electron paramagnetic resonance (ODEPR) using the magnetic circular dichroism of the optical absorption (MCDA). The MCDA spectra in the infrared spectral region consist of a derivative-like line at 1.06 eV,…
GaAs epitaxially grown on porous Si (PS) showed the presence of wires with typical diameters of 60 nm, and lengths in the range 6-10 . The Raman spectra of these samples were studied, and we focused attention on two additional modes appearing as `shoulders' to the LO and TO GaAs lines. The former could be assigned to…
We have grown thin stable films of a good metal, Ag, that have characteristics of bad metals: high resistivity, strong temperature dependence of resistivity, and lack of resistive saturation. For films of different thickness, the temperature-dependent resistance and the Hall effect resistance provide evidence that the…
Bis zu 14 Porphyrinringe enthalten die Titelverbindungen 1, die einfach und regioselektiv aus linearen Nickel-Zink-Porphyrinoiden zugänglich sind. Nach Bestrahlung mit Licht findet ein rascher Energietransfer von den äußeren Porphyrinringen auf die zentrale Diporphyrineinheit statt.
Patterning characteristics of indium tin oxide thin films using different wavelengths of a diode-pumped Q-switched Nd:YLF and a flashlamp-pumped Nd:YAG laser have been studied. While a ripplelike structure in the etched line was formed due to incomplete material removal when the first harmonic of the Nd:YLF or Nd:YAG…
Atomic-resolution Z-contrast images demonstrate unambiguously that the annealed, metalorganic chemical vapor deposition derived transparent In2O3–ZnO films have a polytypoid microstructure, consisting of ZnO slabs of variable width separated by single In–O octahedral layers. These In–O layers induce a polarity inversi…
The search for better, more efficient and at the same time more transparent NLO chromophores has led to the development and investigation of new, alternative chromophore types. A new and quite general synthetic route to ring-substituted truxenones is presented, and the linear and nonlinear optical and redox properties…
Perovskite manganese oxide materials known for the phenomenon of colossal magnetoresistance often exhibit anomalously large 1/f noise and large, temperature-dependent ferromagnetic resonance (FMR) linewidths. We show that in epitaxial films, these anomalies are very sensitive to oxygen partial pressure during film gro…
Neutron scattering investigations of the paramagnetic correlations in the layered manganite ${\mathrm{La}}_{1.2}{\mathrm{Sr}}_{1.8}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$, which exhibits colossal magnetoresistance above the Curie transition at ${T}_{C}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}112\mathrm{K}$, show…
Magnetic Langmuir–Blodgett films containing well-organized monolayers of single-molecule magnets are reported. The single-molecule magnets in question are high-spin molecular clusters of the type [Mn12O12(carboxylate)16]. The structure of such multilayered inorganic–organic composites is depicted schematically in the…
The Mott-Hubbard insulator $(\mathrm{TMTTF}{)}_{2}{\mathrm{PF}}_{6}$ is well known to have a spin-Peierls ground state at ambient pressure below 18 K, although antiferromagnetic order is stabilized for $P>{P}_{c}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.9$ GPa hydrostatic pressure. Near ${P}_{c}$, the tr…
Depletion-driven self-assembly in binary colloidal mixtures is studied via the time evolution of the cluster-size distribution and structure factor as the mixtures equilibrate after shear melting. The data suggest a two-stage crystallization process governed by an initial collapse into an amorphous metastable state, t…