Materials Literature
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Alcohol adducts of the N -heterocyclic carbene, 1,3,4-triphenyl-4,5-dihydro-1 H -1,2-triazol-5-ylidene (NHC), function as excellent single-component catalyst/initiators for the ring-opening polymerization of lactide and β-butyrolactone. Their reversible dissociation at elevated temperatures generates alcohol and triaz…
In electrical engineering metamaterials have been developed that offer unprecedented control over electromagnetic fields. Here we show that general relativity lends the theoretical tools for designing devices made of such versatile materials. Given a desired device function, the theory describes the electromagnetic pr…
We investigated spin dependent transport through Fe/GaAs/Fe tunnel junctions. The tunneling magnetoresistance effect (TMR) was probed for different types of Fe/GaAs interfaces. For interfaces cleaned by hydrogen plasma the TMR effect is increased and observable at room temperature. If an epitaxial Fe/GaAs(001) interfa…
Using density functional theory with the generalized gradient approximation and ultra-soft pseudo-potentials, we have calculated structural relaxations of the Cu(532) surface which contains steps and kinks. We find the relaxation pattern to oscillate dramatically for atoms in the first 10 layers before decaying rapidl…
We have performed ab initio electronic structure calculations of C and S adsorption on two vicinal surfaces of Pd with different terrace geometry and width. We find both adsorbates to induce a significant perturbation of the surface electronic and geometric structure of Pd(533) and Pd(320). In particular C adsorbed at…
The formalism of Kohn and Sham uses a specific (model) hamiltonian which highly simplifies the many-electron problem to that of noninteracting fermions. The theorem of Hohenberg and Kohn tells us that, for a given ground state density, this hamiltonian is unique. In principle, this density can be chosen as that of the…
A new type of (Ga,Mn)As microstructures with laterally confined electronic and magnetic properties has been realized by growing (Ga,Mn)As films on [1-10]-oriented ridge structures with (113)A sidewalls and (001) top layers prepared on GaAs(001) substrates. The temperature- and field-dependent magnetotransport data of…
In this paper we present a theoretical analysis of the effect of local geometrical structure of the Fermi surface on the surface impedance of a metal at the anomalous skin effect. We show that when the Fermi surface includes nearly cylindrical and/or flattened segments it may significantly change both magnitude and fr…
The investigation on the formation mechanism of helical structures and the synthesis of helical materials is attractive for scientists in different fields. Here we report the synthesis of helical mesoporous materials with chiral channels in the presence of achiral surfactants. More importantly, we suggest a simple and…
Assembly time: Thin films of [Fe(pyrazine){M(CN)4}] (M=Ni, Pd, or Pt) coordination polymers were assembled sequentially through coordinate bonding on gold surfaces (see scheme). These multilayers exhibit spin-crossover phenomena with hysteresis at room temperature.
Abstract Polyvinyl alcohol (PVA) nanofibers containing Ag nanoparticles were prepared by electrospinning PVA/silver nitrate (AgNO 3 ) aqueous solutions, followed by short heat treatment, and their antimicrobial activity was investigated for wound dressing applications. Since PVA is a water soluble and biocompatible po…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMultidimensional Tunneling, Recrossing, and the Transmission Coefficient for Enzymatic ReactionsJingzhi Pu, Jiali Gao, and Donald G. TruhlarView Author Information Department of Chemistry and Supercomputer Institute, University of Minnesota, 207 Pleasant Street S.E., Minneap…
Preparation of FRET-based quantum dots as protease sensors-RGDC peptide molecules are bound to the surface of CdSe/ZnS quantum dots. The peptide molecules are then labeled with rhodamine dye molecules. The emission color of the quantum dots change from green to orange due to fluorescence resonance energy transfer (FRE…
We present an experimental study of a low-Reynolds number shear flow between two surfaces, one of which has a regular grooved texture augmented with a superhydrophobic coating. The combination reduces the effective fluid-surface contact area, thereby appreciably decreasing the drag on the surface and effectively chang…
Nanomaterial properties differ from those bulk materials of the same composition, allowing them to execute novel activities. A possible downside of these capabilities is harmful interactions with biological systems, with the potential to generate toxicity. An approach to assess the safety of nanomaterials is urgently…
We present results from cryogenic tests of volume-phase holographic (VPH) gratings at approximately 100 K. The aims of these tests are to see whether the diffraction efficiency as a function of wavelength is significantly different at a low temperature from that at room temperature and to see how the performance of a…
This paper presents the experimental set-up for high strain-rate tests at elevated temperatures in a split-Hopkinson tension bar. A high current was sent through the specimen, whereby direct resistance heating increased the temperature in the material to 300°C within a few seconds. Such a fast increase reduces the hea…
This paper addresses experimental and numerical modelling aspects of material characterisation process concerning strain localisation and ductile fracture preceding the design of aerospace structures threatened by impact. A holistic approach to predictive modelling of the observed phenomena is presented by outlining t…
Optical absorption (OA) and thermally stimulated luminescence measurements were performed on NaCl:Cu+(0.04 and 0.08%) crystals blocks grown by the Czochralski technique. The NaCl:Cu+ crystals were exposed to gamma rays from a 60Co source (0.954-30 kGy) as well as UV radiation. The radiation-induced defects were mainly…
Using molecular dynamics simulation with the embedded atom method, the structural properties of liquid NiAl in a pressure range of 0-20 GPa are investigated with a quenching rate of 2 K ps(-1). Not only is vitrification of liquid at low temperature detected, but also crystallization by change of average atomic volume…