Materials Literature
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We present an atomistic investigation on mechanical loading effects in a model fiber-reinforced $\ensuremath{\beta}\text{\ensuremath{-}}\mathrm{Si}\mathrm{C}$ monocrystal where a crack is present. Our simulations are both consistent with the basic results of elementary continuum mechanics and provide a deeper physical…
Enzymatic degradation processes of flat-on lamellar crystals in melt-crystallized thin films of poly[(R)-3-hydroxybutyric acid] (P(3HB)) and its copolymers were characterized by real-time atomic force microscopy (AFM) in a phosphate buffer solution containing PHB depolymerase from Ralstonia pickettii T1. Fiberlike cry…
The synthesis, structure, and magnetic properties of two new tetranuclear Cu(II) complexes containing N,N,N',N'-tetraethylpyridine-2,6-dithiocarboxamide (S-dept) of formula [Cu(2)Cl(2)(mu-S-dept)(2)][Cu(2)Cl(4)(mu-Cl)(2)] (1) and [Cu(2)(mu-Cl)(2)(S-dept)(2)][CuCl(3)(EtOH)](2) (2) are reported. Their X-ray crystal stru…
We report the theoretical investigations on the giant magnetocaloric compound ${\mathrm{MnFeP}}_{0.45}{\mathrm{As}}_{0.55}$. The magnetic state equation used takes into account the magnetoelastic effect that leads the magnetic system to order under first order paramagnetic-ferromagnetic phase transition. The model par…
For patients with severe coronary artery and distal peripheral vascular disease not amenable to angioplasty and lacking sufficient autologous vessels there is a pressing need for improvements to current surgical bypass options. It has been decades since any real progress in bypass material has reached mainstream surgi…
Understanding of oxidative processes such as solution-phase ozonolysis in multiwalled carbon nanotubes (MWNTs) is of fundamental importance in devising applications of these tubes as components in composite materials, as well as for development of cutting and filling protocols. We present here an evaluation of various…
Poly[ N, N ‘ -(1,4-phenylene)-3,3‘4,4‘-benzophenonetetracarboxylic amic acid] (PAmA) with grafted poly(methyl methacrylate) (PMMA) side chains (PAmA- g -PMMA) was synthesized via thermally induced graft copolymerization of methyl methacrylate (MMA) with ozone-pretreated PAmA in the reversible addition-fragmentation ch…
Multiwalled carbon nanotubes (MWNTs) were functionalized by oxidation with potassium permanganate using a phase transfer catalyst. The functionalized nanotubes (f-CNTs) were allowed to react with a functional chemical such as 3-methacryloxypropyltrimethoxysilane (3-MPTS). The f-CNTs and the reaction product of f-CNTs…
Colloidal semiconductor nanocrystals: We present a hybrid inorganic–organic near-infrared light-emitting device (see picture), which comprises a blend of a blue–green emitting, hole-conducting conjugated polymer, methyl-substituted ladder-type poly(para-phenylene), and HgTe nanocrystals. The demonstrated device emits…
Extended X-ray absorption fine structure (EXAFS) analysis of zinc sorption on montmorillonite showed that different types of surface complexes or surface precipitates were formed depending on the reaction time. With an initial zinc concentration of 10(-3) M at neutral pH, zinc remained octahedrally coordinated with ab…
We report a dynamic radiography system with a carbon nanotube based field-emission microfocus x-ray source. The system can readily generate x-ray radiation with continuous variation of temporal resolution as short as nanoseconds. Its potential applications for dynamic x-ray imaging are demonstrated. The performance ch…
We have designed, produced, and experimentally characterized $2.7\phantom{\rule{0.3em}{0ex}}\mathrm{mm}$ thick composite panels having negative refractive index between 8.4 and $9.2\phantom{\rule{0.3em}{0ex}}\mathrm{GHz}$. The composite metamaterial is fabricated using conventional commercial multilayer circuit-board…
We discuss different magnetic phenomena observed in carbon-based structures, in particular the diamagnetism, paramagnetism and ferromagnetism observed in graphite, disordered carbon, fullerenes and irradiated carbon structures.
In order to study a possible magnetic proximity effect in magnetite-carbon structures, we have performed magnetization measurements of graphite-magnetite composites with different mass ratios as well as the measurement of the magnetoresistance of one of them and of the magnetization of a magnetite-carbon bilayer. The…
We have investigated the band-gap pressure coefficients of self-assembled InAs/GaAs quantum dots by calculating 17 systems with different quantum dot shape, size, and alloying profile using atomistic empirical pseudopotential method within the ``strained linear combination of bulk bands'' approach. Our results confirm…
The ferroelectric properties of disorder $\mathrm{Pb}({\mathrm{Zr}}_{0.5}{\mathrm{Ti}}_{0.5}){\mathrm{O}}_{3}$ thin films are investigated with Monte Carlo simulations on the basis of a first-principles-derived Hamiltonian. It is found that there exists a critical thickness of about three unit cells $(\ensuremath{\sim…
A new method (NM) for filtering three-dimensional reconstructed densities is proposed. The algorithm is tested with simulated spectra and employed to study the electronic structure of the rare-earth compound LaB6. For this system, momentum densities are reconstructed from theoretical and experimental two-dimensional a…
We report on density-functional-based tight-binding (DFTB) simulations of a series of amorphous arsenic sulfide models. In addition to the charged coordination defects previously proposed to exist in chalcogenide glasses, a novel defect pair, [As4]--[S3]+, consisting of a four-fold coordinated arsenic site in a seesaw…
Aqueous solutions of europium(III) and terbium(III) tris(dipicolinates), around physiological pH are shown to be convenient secondary standards in the determination of quantum yields of lanthanide complexes containing these ions. Conditions for which a strict linearity is observed between the concentration of the solu…
Self-generation of ionic organic capping from nonionic surfactant polyoxyethylene (20) sorbitan trioleate (Tween-85) has been realized for the controlled synthesis of single crystalline Co(3)O(4) quantum dots (3.0-5.7 nm) in cubic morphology from related layered hydroxide precursors at 80-95 degrees C. With chemical m…