Materials Literature
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We present a real-time investigation of ultrafast carrier dynamics in single-wall carbon nanotube bundles using femtosecond time-resolved photoelectron spectroscopy. The experiments allow to study the processes governing the subpicosecond and the picosecond dynamics of non-equilibrium charge-carriers. On the subpicose…
The Gd 2 (Ti 1 - y Zr y ) 2 O 7 pyrochlore series undergoes a structural phase transition from pyrochlore ( Fd 3̄ m ) to defect fluorite ( Fm 3̄ m ) that can be driven compositionally by increasing the Zr content or thermally by sintering Zr-rich compositions at temperatures above 1550 °C. Our results demonstrate that…
The thermal, hydrothermal, and mechanical stabilities of a wide range of ordered mesoporous materials, in particular, the molecular sieves MCM-41, MCM-48, HMS, FSM-16, KIT-1, PCH, and SBA-15, have been studied in detail using X-ray diffraction (XRD) and nitrogen sorption. The thermal stability was found to be strongly…
Laminar and tumbling flow regimes in a high shear flow, as well as transition from a flow alignment regime to a tumbling situation are investigated in the polar liquid crystal p-n-hexyloxybenzylidenep′-aminobenzonitrile (HBAB) near a charged surface. The relaxation of the alignment angle θ(τ) to its equilibrium θbulk…
A molecular dynamics simulation has been performed to investigate the structure and the dynamics of liquid and supercooled metatoluidine. H-bonding and clustering has been shown to dominate the structure of the liquid. An extensive analysis of the cluster formation and of its relation with the characteristic prepeak o…
Using ultrasonic spectroscopy, the frequency dispersions of ultrasonic velocity and attenuation were measured for single crystal 0.72 Pb(Mg1/3Nb2/3)−0.28 PbTiO3 (PMN−28%PT) with engineered domain structures in the frequency range of 50–110 MHz. We found that the velocity dispersion and attenuation are very small for t…
In this report we point out that any nucleation and growth kinetics can be treated, in principle, as a problem of correlated nucleation. In other words, against a higher mathematical complexity, one can eliminate the concept of phantoms first introduced by Avrami [J. Chem. Phys. 7, 1103 (1939); 8, 212 (1940)]. In this…
Long time molecular dynamics simulations of one-dimensional Lennard-Jones systems reveal that while the diffusion coefficient of a tagged particle indeed goes to zero in the very long time, the mean-square displacement is linear with time at short to intermediate times, allowing the definition of a short time diffusio…
[NH4]2[MoS4] reacts with CuBr and [Bu4N]Br in the solid state to afford an intermediate product with proposed constitution [Bu4N]4[MoS4Cu6Br8] (1). Treatment of cluster (1) with an equal equivalent of dppf in CH3CN–DMF solution resulted in the formation of a pentanuclear cluster [MoS4(Cudppf)2]·2DMF·CH3CN (2). Cluster…
Dynamic light scattering is used to obtain the anchoring energy coefficients of nematic liquid crystal (4-n-pentyl-4(')-cyanobiphenyl) on rubbed nylon and photoactive poly-(vinyl-cinnamate). The anchoring coefficients are determined by measuring the relaxation time of the fundamental director fluctuation mode in a hom…
Quasielastic neutron scattering (QENS) has been used to investigate the single-particle dynamics of interfacial water in dicalcium silicate (C2S)/water paste. Our previous neutron-scattering studies on interfacial water have focused attention on the translational dynamics of the center of mass of water molecules. In t…
Structural studies show that the solvolysis of a nitrate group in the heavy lanthanide complexes [Ln(terpy)(NO3)3] {Ln = Yb, Lu; terpy = 2,2′:6′,2″-terpyridine} is stereoselective. In the complexes [Ln(terpy)(NO3)3(EtOH)], the ‘equatorial nitrate group’, which lies in the same plane as the terpy ligand, coordinates in…
A tris-tridentate segmental ligand has been designed for the self-assembly of homotrimetallic triple-stranded lanthanide helicates possessing different coordination sites along the threefold axis.
Optical spectroscopy was used to investigate the optical gap ( $2\ensuremath{\Delta}$) due to charge ordering (CO) and related pseudogap developments with $x$ and temperature ( $T$) in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{3}$ ( $0.48\ensuremath{\le}x\ensuremath{\le}0.67$). Surprisingly, we…
Optical recording in a ferroelectric liquid crystal using smectic layer rotation induced by the application of asymmetric voltage pulses has been proposed. This recording method is based on the temperature dependence of the rotation rate and the fact that the rate in the smectic A (SmA) phase is considerably smaller t…
The infrared, Raman and inelastic neutron scattering spectra of the approximately tetrahedral ternary metal hydrides: Mg2NiH4, Rb3ZnH5 and their deuterides have been observed and assigned. This has enabled a comparison of some of the properties of the first row transition ternary metal hydrides.
The effect of ambient-pressure reduction on multibubble sonochemiluminescence (MBSCL) is studied experimentally with a luminol solution through measurements of MBSCL intensity as a function of ultrasound irradiation time, applied voltage to a transducer and ultrasonic frequencies to accomplish high efficiency in chemi…
Iodine-doped multiwall carbon nanotubes (I-MWNTs) were characterized by means of Raman scattering and thermogravimetric analysis. The results show that multiwall carbon nanotubes (MWNTs) can be effectively doped by iodine and exchange electrons with iodine. Iodine atoms form charged polyiodide chains inside tubes of d…
A negative-tone inorganic-organic hybrid SiO(2):TiO(2) glass is investigated for fabrication of refractive microlenses. This sol-gel material enjoys an advantage over materials used in conventional photoresist-based fabrication techniques in that it lends itself to a single-step etching-free process. The application o…
We have performed a comprehensive study of the electronic structure and magnetic properties of structurally characterized models for diiron-oxo proteins. Results from Kohn–Sham density functional theory show that two complexes, with formula Fe2(μ-O)(μ-O2CCH3)2(HBpz3)2 and [Fe2(μ-OH)(μ-O2CCH3)2(HBpz3)2]+, are strongly…