Materials Literature
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The average dimensions of poly(amido amine) (PAMAM) dendrimers of generations G5 and G8 are studied by small-angle neutron scattering (SANS) as a function of solvents of differing quality, the composition of mixtures of a good solvent and a nonsolvent, and temperature. The radius of gyration, R g, of the G8 dendrimer…
Process schemes for single-step syngas-to-dimethyl ether (DME) were developed in two stages: (1) the performance of the syngas-to-DME reactor was optimized with respect to the feed gas composition and (2) the optimal reactor feed gas system was integrated with synthesis gas generators. It was shown that the reactor pe…
The synthesis of the enantiomeric forms of the two- and three-dimensional polymers: {[NBu(4)][MnCr(ox)(3)]}(n)() (1) (Bu = n-butyl, ox = oxalate), {[M(bpy)(3))][LiCr(ox)(3)]}(n)() (M = Ni (2), Ru (4)) (bpy = 2,2'-bipyridine), {[M(bpy)(3))][Mn(2)(ox)(3)]}(n)() (M = Ni (3), Ru (5)) using resolved [Cr(ox)(3)](3)(-) and […
The effect of Al substitution on the hydrothermal stability of Si−Al−MCM-41 (Si/Al = 50) under different treatment conditions has been investigated in detail, and a fundamental understanding is discussed based on its effect on both geometrical and chemical properties of MCM-41. Compared with Si−MCM-41, the small amoun…
The oxidation of 7,8-dihydro-8-oxoguanine (8-oxoG)-containing oligodeoxynucleotides has been investigated using a variety of oxidants, including one-electron oxidants (Ir(IV), Fe(III), NiCR/KHSO 5, and SO 4 - • ) as well as singlet oxygen, generated both photochemically and thermally. The extents of oxidation in singl…
We present a method for constructing a scalar-relativistic pseudopotential which provides exact agreement with relativistic Dirac-Slater all-electron eigenvalues at the reference configuration. All-electron wave functions are self-consistently computed in the valence region at the exact all-electron scalar relativisti…
Magnetotransport properties of ferromagnetic semiconductor (Ga,Mn)As have been investigated. Measurements at low temperature (50 mK) and high magnetic field (<= 27 T) have been employed in order to determine the hole concentration p = 3.5x10^20 cm ^-3 of a metallic (Ga0.947Mn0.053)As layer. The analysis of the tempera…
Numerous and all unsuccessful attempts of experimental search for monopole in cosmic rays and on accelerators in high energy particle collisions have been done since the possibility of existence of a magnetic monopole has been surveyed in 1931. Also the searches have been carried out in mica for monopole tracks as wel…
Equilibrium structure, local densities of states, and electronic transport in a gold nanowire made of a four-atom chain supported by two gold electrodes, which has been imaged recently by high-resolution electron microscopy, and chemical modification of the wire via the adsorption of a methylthiol molecule, are invest…
Incoherent-inelastic neutron scattering data are obtained over the energy range of lattice and internal vibrations of water molecules in phases of ice prepared by pressure-induced amorphization (high-density amorphous ice, hda), by thermal annealing of hda (low-density amorphous ice, lda), and by rapidly cooling water…
A method is described to synthesize silicon carbide (SiC)-filled boron nitride (BN) nanotubes (NT) simultaneously in high yield by using carbon nanotubes (CNTs) as templates. This method combines both carbon nanotube-substitution reaction and confined reaction. Through the CNT-substitution reaction, CNTs react with bo…
We have measured an enhancement factor of Raman signal up to 30 times using a Fabry-Pérot structure made of porous silicon (PS) layers of different porosity. The obtained enhancement was due to the coupling of the laser radiation and Stokes photons of porous silicon with the microcavity mode at the optimal laser beam…
Nanocrystalline silicon embedded SiO2 matrix is formed by annealing the SiOx films fabricated by plasma enhanced chemical vapor deposition technique. Absorption coefficient and photoluminescence of the films have been measured at room temperature. The experimental results show that there exists an exponential absorpti…
The third-order optical nonlinearity of metal(dmit)2 was investigated with femtosecond optical Kerr effect at 830 nm wavelength. The nonresonant second-order hyperpolarizability for the didodecyldimethylammonium–Au(dmit)2 (2C12–Au) molecule was estimated to be as large as 2.2×10−32 esu.
The electrical and thermal transport properties of a single-phase quasicrystalline material of composition Al70.8Pd20.9Mn8.3 have been measured as a function of temperature (T) over a range of 10 K&lt;T&lt;320 K. The following room-temperature values were found: electrical conductivity [640 (Ω cm)−1], Seebeck…
Si nanowires (SINWs) with different diameters have been synthesized by laser ablation in different ambient gases. SINWs with the diameter distribution peaks at ∼13.2 and ∼9.5 nm have been obtained respectively in He and Ar (5% H2). SINWs produced in N2 had the smallest peak diameter at 6 nm, and are mixed in with some…
Photoinduced surface relief grating (SRG) formation on azopolymer films is discussed precisely using a fluid mechanics model which takes depth dependence of photoinduced driving force and velocity distribution in the film surface into account. Formulation for the SRG dynamics is derived analytically as a function of f…
The elastic constants of tetrahedral amorphous carbon (ta-C) and hydrogenated tetrahedral amorphous carbon (ta-C:H) thin films were determined nondestructively by surface Brillouin scattering. Besides the usual Rayleigh surface mode, we also observe a new pseudosurface acoustic mode of longitudinal polarization, which…
Formulas to describe the photoabsorption and the photon scattering by a plasma or a liquid metal are derived in a unified manner with each other. It is shown how the nuclear motion, the free-electron motion and the core-electron behaviour in each ion in the system determine the structure of photoabsorption and scatter…
A new class of strongly infrared active structures is identified for phase III of compressed molecular H2 by constant-pressure ab initio molecular dynamics and density-functional perturbation calculations. These are planar quadrupolar structures obtained as a distortion of low-pressure quadrupolar phases, after they b…