Materials Literature
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The build-up of exciton populations in resonantly laser excited semiconductors is studied microscopically. For excitation at the $2s$-exciton resonance, it is shown that polarization with a strict $s$-type radial symmetry can be efficiently converted into an incoherent $p$-type population. As a consequence, inversion…
We investigate the motion of a hard cylinder rolling down a soft inclined plane. The cylinder is subjected to a viscous drag force and stochastic fluctuations due to the surrounding medium. In a wide range of parameters we observe bistability of the rolling velocity. In dependence on the parameters, increasing noise l…
If magnetic semiconductors are ever to find wide application in real spintronic devices, their magnetic and electronic properties will require tailoring in much the same way that band gaps are engineered in conventional semiconductors. Unfortunately, no systematic understanding yet exists of how, or even whether, prop…
Pseudobinary ${\mathrm{G}\mathrm{e}\mathrm{T}\mathrm{e}\ensuremath{-}\mathrm{S}\mathrm{b}}_{2}{\mathrm{Te}}_{3}$ is in wide use today as a memory material in phase-change optical disks such as DVD-RAMs. ${\mathrm{GeSb}}_{2}{\mathrm{Te}}_{4},$ one of the intermetallic compounds used in this binary system, when in therm…
A supramolecular organosilane, 2-(3-(triethoxysilyl)propylaminocarbonylamino)-6-methyl-4[1H]pyrimidinone comprising quadruple hydrogen bonds has been synthesized in one step from commercially available starting materials. The synthesized supramolecular organosilane can be stabilized and phase-separated by dimerization…
We have analyzed differential cross sections (DCSs) for the elastic scattering of electrons by neutral atoms that have been derived from two commonly used atomic potentials: the Thomas–Fermi–Dirac (TFD) potential and the Dirac–Hartree–Fock (DHF) potential. DCSs from the latter potential are believed to be more accurat…
The reaction of MnCl2.4H2O (3 equiv), pyridine-2,6-dimethanol (pdmH2) (10 equiv), and NaN3 (10 equiv) in MeOH/MeCN (1:2 v/v) with NMe4OH (1 equiv) gave [Mn25O18(OH)2(N3)12(pdm)6(pdmH)6](Cl)2.12MeCN (1.12MeCN) in approximately 30% yield. The cation of complex 1 comprises five Mnx layers of three types in an ABCBA arran…
A general strategy is described which allows for transferring hydrophobically capped nanocrystals from organic to aqueous solution by wrapping an amphiphilic polymer around the particles. In particular, high quality CoPt 3, Au, CdSe/ZnS, and Fe 2 O 3 nanocrystals have been water-solubilized in this way. Analysis with…
A model for the structure of amorphous molybdenum trisulfide, a-MoS3, has been created using\nreverse Monte Carlo methods. This model, which consists of chains of MoS6 units sharing three sulfurs\nwith each of its two neighbors and forming alternate long, nonbonded, and short, bonded, Mo−Mo\nseparations, is a good fit…
Mechanical behaviour of metallized polyimide Kapton films was studied. The adhesion of metallized films to Kapton films is approximately hundred-folds higher than that of coatings made by usual sputter deposition of a metal on a polymer substrate. Multiple cracking of a metallized film was observed. Cracks of two diff…
The electrical and magnetic transport properties have been studied in a series of samples Nd0.7(Ca,Sr,Ba)0.3MnO3 with a fixed average A-site cation radius 〈rA〉 = 1.21 Å. The residual resistivity increases dramatically and the metal-transition and Curie temperatures decrease systematically with increasing A-site cation…
In this paper the effects of Fe-Fe bond length change on magnetic properties and magnetic entropy change have been investigated on LaFe12.4-xSixCo0.6 and LaFe12.3-xAlxCo0.7 intermetallic compounds. According to the analyses of Fe-Fe bond length change, the variation of Curie temperature and the unusual magnetic phase…
Abstract For Abstract see ChemInform Abstract in Full Text.
Second-order optical nonlinearity was found to be generated in high-purity silica glasses when they were exposed to x-ray radiation and then thermally poled. Two kinds of second-order optical nonlinearity, near-surface nonlinearity localized in a thin layer near the sample surface and bulk nonlinearity spreading throu…
The role of neutral radicals and charged ions in a low-pressure limit of plasma-enhanced chemical vapor deposition of diamond has been studied by plasma diagnostics and a kinetic rate analysis for radicals. The fluxes of atomic hydrogen (H), methyl radicals (CH3), and ionic species were determined by optical absorptio…
The family of solid solutions of the type β-K2(Bi1−zSbz)8Se13 (0<z⩽1) was studied with respect to thermal conductivity as a function of temperature and stoichiometry. At low temperature, the variation of lattice thermal conductivity with composition shows a transition from a typical crystalline to glasslike beh…
The dynamics of polarization switching have been investigated over extremely broad time (10−8<t<102 s) and field ranges for hard, soft, and relaxor ferroelectrics based on aliovalent modified Pb(Zr1−xTix)O3. The results unambiguously demonstrate important differences in the polarization switching mechani…
The magnetic structure and magnetic phase transitions of the ${\mathrm{Pr}}_{5}{\mathrm{Ge}}_{4}$ compound are investigated by means of neutron powder diffraction (NPD) and small-angle neutron scattering (SANS). Both NPD and SANS indicate the existence of two magnetic phase transitions at 25 K and 42 K. Refinement of…
Abstract Poly(butylene adipate‐ co ‐succinate) (PBAS), an aliphatic polyester, is known for its excellent biodegradability, but its physical and mechanical properties are poor. To improve the physical properties, stiff aromatic rings were added to PBAS through transesterification with poly(ethylene terephthalate) (PET…
The pyridoxal 5'-phosphate-dependent enzymes tyrosine phenol-lyase and tryptophan indole-lyase were encapsulated in wet nanoporous silica gels, a powerful method to selectively stabilize tertiary and quaternary protein conformations and to develop bioreactors and biosensors. A comparison of the enzyme reactivity in si…