Materials Literature
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Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The differe…
Effect of hydrostatic pressure and magnetic field on electrical resistance of the Kondo-like perovskite manganese oxide, La$_{0.1}$Ce$_{0.4}$Sr$_{0.5}$MnO$_3$ with a ferrimagnetic ground state, have been investigated up to 2.1 GPa and 9 T. In this compound, the Mn-moments undergo double exchange mediated ferromagnetic…
We explore how chemical patterning on surfaces can be used to control drop wetting. Both numerical and experimental results are presented to show how the dynamic pathway and equilibrium shape of the drops are altered by a hydrophobic grid. The grid proves a successful way of confining drops and we show that it can be…
CdP2 nanoclusters were fabricated by incorporation into pores of zeolite Na-X and by laser ablation. Absorption and photoluminescence (PL) spectra of CdP2 nanoclusters in zeolite were measured at the temperatures of 4.2, 77 and 293 K. Both absorption and PL spectra consist of two bands blue shifted with respect to bul…
Martensitic phase transitions appear in a diverse range of natural and engineering material systems. Examination of the energetics and kinetics of the transformation requires an understanding of the atomic mechanism for the transformation. A systematic pathway generation and sorting algorithm is presented and applied…
We have modeled the layer-by-layer assembly process of flexible polyelectrolytes on flat surfaces. The multilayer has a three-zone structure. An exponential growth is found for the first several layers, followed by a linear growth for subsequent layers evolving towards a steady state. While adjacent layers are highly…
We discuss the transport anomalies associated with the development of heavy electrons out of a neutral spin fluid using the large-N treatment of the Kondo-Heisenberg lattice model. At the phase transition in this model the spin excitations suddenly acquire charge. The Higgs process by which this takes place causes the…
It is shown that perfect imaging of a point source both in near- and far-field regions contradicts electrodynamics although ``superlensing'' is impossible only in the far-field region. These general statements are illustrated by detailed study of evanescent wave propagation in a photonic crystal that is known to be a…
Cobalt-doped ZnO (Co2+:ZnO) films were studied by magnetic circular dichroism (MCD) spectroscopy. A broad 300 K ferromagnetic MCD signal was observed between 1.4 and 4.0 eV after introducing shallow donor states by exposure of paramagnetic Co2+:ZnO films to zinc vapor. The new sub-bandgap ferromagnetic MCD intensity i…
We study the influence of structural lattice fluctuations on the elastic electron transport in single-wall carbon nanotubes within a density-functional-based scheme. In the linear-response regime, the linear conductance is calculated via configurational averages over the distorted lattice. Results obtained from a froz…
We study triangular lattice spin-$1∕2$ system with antiferromagnetic Heisenberg and ring exchanges using variational approach focusing on possible realization of spin-liquid states. Trial spin liquid wave functions are obtained by Gutzwiller projection of fermionic mean-field states and their energetics is compared ag…
Structural and magnetic transformations in the Heusler-based system ${\mathrm{Ni}}_{0.50}{\mathrm{Mn}}_{0.50\ensuremath{-}x}{\mathrm{Sn}}_{x}$ are studied by x-ray diffraction, optical microscopy, differential scanning calorimetry, and magnetization. The structural transformations are of austenitic-martensitic charact…
Abstract The wavelength dependence of the third‐order optical nonlinearity and response of the J‐like aggregates of a cyanine dye called NK‐3261 in a neat film were measured by the femtosecond degenerate four‐wave mixing (DFWM) technique under resonant conditions. The temporal profile of the DFWM signal of NK‐3261 J‐l…
Abstract New asymmetric (salen)Mn III and UO 2 complexes containing a calix[4]arene unit in the ligand framework were synthesized. The UO 2 complexes were characterized by 1 H‐, 13 C‐, 2D TOCSY and T‐ROESY NMR spectroscopy. Furthermore, the structure of one UO 2 complex was determined by single‐crystal X‐ray analysis.…
Abstract The synthesis and the nonlinear optical properties of an axially substituted binuclear InCl/InCl phthalocyanine 1 with an unsymmetrical substitution pattern are described. The preparation of this new type of binuclear phthalocyanine has been carried out through a multi‐step synthetic strategy, which was speci…
Abstract Monodisperse spherical ZrO 2 particles were prepared by controlled hydrolysis of zirconium tetraalkoxide in alcoholic solution. Ageing the reaction solution at 60 °C for 4 h yields particles with sizes in the range between 200 and 2000 nm. The influence of various ions and surfactants on the final product was…
Phase-field models are very attractive in view of their numerical simplicity. With only a few lines of code, one can model complex physical situations such as dendritic growth. From this point of view, they constitute very interesting tools for teaching purposes at graduate level. The main difficulty with these models…
Abstract Summary: Polypyrrole (PPy), polyaniline (PANI), and poly(ethylenedioxythiophene) (PEDOT) aqueous dispersions were prepared by polymerizing the corresponding monomer in the presence of a polymeric ionic liquid (PIL), poly(1‐vinyl‐3‐ethylimidazolium bromide). By addition of bispentafluoroethanesulfonimide lithi…
Abstract The hydrothermal reaction of an aqueous ammonium heptamolybdate solution with first‐row transition metal salts in the presence of 2‐aminopyridine at around 180 °C and under autogenous pressure yields several molybdates, such as the 1D chains in (C 5 N 2 H 7 ) 4 Mo 8 O 26 ( 1 ), zero‐dimensional (C 5 N 2 H 7 )…
Single crystals of the filled-skutterudite compound NdOs$_4$Sb$_{12}$ have been investigated by means of electrical resistivity, magnetization, and specific heat measurements. The NdOs$_4$Sb$_{12}$ crystals have the LaFe$_4$P$_{12}$-type cubic structure with a lattice parameter of 9.3 Å. Possible heavy-fermion behavio…