Materials Literature
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The prospects for high thermoelectric performance in phosphide skutterudites are investigated based on first principles calculations. We find that stoichiometric CoP_3 differs from the corresponding arsenide and antimonide in that it is metallic. As such the band structure must be modified if high thermopowers are to…
We examine, using molecular dynamics simulation, the structure and thermodynamics of the (100) and (111) disordered face-centered cubic (FCC) crystal/melt interfaces for a binary hard-sphere system. This study is an extension of our previous work, [Phys. Rev. E 54, R5905 (1996)], in which preliminary data for the (100…
We report the first audio frequency dielectric constant measurements of CO and N_2 in their solid phases. We have observed several new features, including (1) strong hysteresis effects above an onset temperature $T_{h} \simeq 42 K$ in the β-phase of pure N_2, (2) absence of the expected short range antiferroelectric d…
A transition-metal oxide NaCo_2O_4 is a layered oxide in which CoO_2 and Na alternately stack along the c axis. Recently we have found that this compound shows unusually large thermopower with low resistivity, which is comparable to those of Bi_2Te_3. The negative transverse magnetoresistance and the strongly temperat…
The inelastic light scattering in a 2-d electron gas is studied theoretically using the Boltzmann equation techniques. Electron-hole excitations produce the Raman spectrum essentially different from the one predicted for the 3-d case. In the clean limit it has the form of a strong non-symmetric resonance due to the sq…
Telechelic oligo- and poly(dimethylsiloxanes) 1 and 2, with two ureidopyrimidone (UPy) functional groups, have been prepared via a hydrosilylation reaction. The compounds have been characterized in solution by 1 H NMR and viscometry and in the solid state by 1 H NMR and 13 C NMR, FTIR, and rheology measurements. The m…
Exposure of photoluminescent porous Si to alkyllithium reagents results in grafting of the alkyl group to the silicon surface by formation of a Si−C bond. The reaction is proposed to proceed by addition of the alkyllithium reagent across a surface Si−Si bond, forming Si−alkyl and Si−Li surface species. The highly reac…
We investigate to what extent the specific heat of amorphous silica can be calculated within the harmonic approximation. For this we use molecular dynamics computer simulations to calculate, for a simple silica model (the BKS potential), the velocity autocorrelation function and hence an effective density of states g…
This paper presents a comprehensive analysis of simple models useful to analyze the growth of nanostructures obtained by cluster deposition. After detailing the potential interest of nanostructures, I extensively study the first stages of growth (the submonolayer regime) by kinetic Monte-Carlo simulations. These simul…
Al(110) has been studied for temperatures up to 900 K via ensemble density-functional molecular dynamics. The strong anharmonicity displayed by this surface results in a negative coefficient of thermal expansion, where the first interlayer distance decreases with increasing temperature. Very shallow channels of oscill…
The multireference Møller−Plesset perturbation (MRMP) theory with complete active space self-consistent field (CASSCF) reference functions is applied to the study of the Q and B bands of free-base, magnesium, and zinc porphyrins and their derivatives. The Q band of free-base porphyrin is so weak because the transition…
The electrostatic binding of two anionic probe molecules, pyrenetetrasulfonic acid (4-PSA) and 6-carboxyfluorescein (6-CF), to poly(allylamine hydrochloride) (PAH)/poly(sodium 4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDADMAC)/PSS ultrathin multilayer films assembled onto polystyrene (PS) l…
Sonochemistry is the use of ultrasound to enhance or alter chemical reactions. Sonochemistry in the true sense of the term occurs when ultrasound induces “true” chemical effects on the reaction system, such as forming free radicals which accelerate the reaction. However, ultrasound may have other mechanical effects on…
In situ optical microscopy, small–angle light–scattering and X–ray–scattering techniques have been applied to study flow–induced textures in main–chain thermotropic liquid–crystalline polymers (LCPs). In order to gain more insight into the underlying mechanism leading to the formation of microstructure, the effect of…
Small angle x-ray scattering (SAXS) and Rayleigh–Mandelstam–Brillouin (RMB) light scattering as well as ultrasonic sound velocities have been studied in glasses of the system PbO–SiO2 which has an unusually wide range of glass forming ability. The results of scattering are compared with calculations based on the conce…
The magnetoresistance of step-edge structures in La0.7Ca0.3MnO3 films was investigated. Step-edge arrays with 200 steps of height 140–200 nm and step separation 20 μm along [110] were fabricated on LaAlO3 substrates by chemically assisted ion-beam etching. Thin La0.7Ca0.3MnO3 films were deposited on the structured sub…
"Unplug those pores!" could be a slogan common to cosmetologists and polymer chemists. Membranes with nanochannels can be obtained by first forming a film by casting a solution of a triblock and homopolymer mixture, then selectively cross-linking domains in the film by photolysis, and finally forming nanochannels thro…
X-ray diffraction, thermogravimetric (TGA), differential scanning calorimetric (DSC), and impedance analysis were used to study the reported high-temperature phase transitions at 107, 149, 230, and 256 °C in crystals of cesium dihydrogen phosphate, CsH2PO4 (CDP). Our results show strong evidence that at all these temp…
We report an anomalous magnetostriction behavior of the charge ordered compound ${\mathrm{Nd}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3}$. We have found that the applied magnetic field not only gives rise to a large negative magnetoresistance but also produces a huge positive magnetovolume effect. This unusual effect…
Inclusive electron scattering is measured with 4.045 GeV incident beam energy from C, Fe, and Au targets. The measured energy transfers and angles correspond to a kinematic range for Bjorken $x>1$ and momentum transfers from ${Q}^{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1--7(\mathrm{GeV}/c{)}^{2}$. Whe…