Materials Literature
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Reproducible high-yield purification process of singlewalled carbon nanotubes was developed by combining two-step processes of thermal annealing in air and acid treatment. The process involves the thermal annealing in air with the powders rotated at temperatures of 470 °C for 50 min, which burns out the carbonaceous p…
We report the estimation of diffusion constants for oxygen vacancies in MgO based on optical absorption spectra. MgO single crystals were annealed in a reducing atmosphere (H 2 + Ar) to create oxygen vacancies and the samples were annealed in an oxidizing atmosphere (O 2 + Ar) to annihilate them. Fe 3+ impurities in t…
Abstract The homopolyester of 4‐hydroxyphenylacetic acid (HPAA) was synthesized by one‐pot, slurry‐melt, and acidolysis melt polymerization techniques and was characterized by its inherent viscosity and IR and NMR spectra. Differential scanning calorimetry (DSC), polarizing light microscopy (PLM), and wide‐angle X‐ray…
We investigated the temperature-dependent infrared properties of the compound θ-(BEDT-TTF) 2 RbZn(SCN) 4 . At temperatures above the metal-insulator transition, the optical conductivity remains finite in the low-energy region, but shows no conventional Drude feature typical of metals. Below the metal-insulator transit…
We imaged at single-particle resolution the birth, life and death of a sub-critical nucleus containing ~10 3 particles in a crystallizing hard-sphere colloidal fluid at volume fraction ϕ = 0.51. This gives a lower bound to the critical nuclear size for hard-sphere crystallization at this volume fraction.
The crystal structure of m-nitroaniline has been examined at several temperatures over the 90-350 K range. Thermal evolution of the lattice parameters reveals a weak anomaly at 110 K and an important one at 300 K. The thermal expansion coefficients have been calculated at several temperatures and the principal axes cr…
The crystal structure of the commensurate phase of Ca(2)CoSi(2)O(7), dicalcium cobalt disilicate, has been derived from the modulated structure described in (3 + 2)-dimensional space. The structure is orthorhombic P2(1)2(1)2; a = 23.510 (4), b = 23.510 (4), c = 5.025 (1) A (at 170 K), Z = 18. Since the crystal is twin…
The anchoring of the nematic liquid crystal N-(p-methoxybenzylidene)-p-butylaniline (MBBA) on Langmuir-Blodgett monolayers of fatty acids (COOHC(n)H(2n+1)) was studied as a function of the length of the fatty acid alkyl chain n (n=15,17,19,21). The monolayers were deposited onto glass plates coated with indium tin oxi…
Abstract New fluorinated aromatic polyimides were prepared from 1,4‐(4′‐aminophenoxy)‐2‐(3′‐trifluoromethylphenyl)benzene and aromatic dianhydrides via the polycondensation of one‐step high‐temperature and two‐step thermal or chemical imidization methods. Experimental results indicated that some of the polyimides were…
Stress relaxation of model poly(dimethylsiloxane) networks with pendant chains and nearly constant cross-linking density was studied. The networks were obtained by end-linking a mixture of long chains bearing terminal reactive groups with a trifunctional cross-linker. Long poly(dimethylsiloxane) chains in the initial…
Water uptake in diglycidyl ether of butanediol (DGEB) epoxy cured with 4,4‘-diaminodiphenyl sulfone (DDS) was studied using UV reflection spectroscopy. There is a progressive shift to longer wavelength of approximately 13 nm for the DDS reflection peak at 338 nm upon exposure to water, apparently due to hydrogen bondi…
The emission and excitation properties of a SrB 4 O 7 :1% Pr 3+ powder sample and a Sr 0.7 La 0.3 Al 11.7 Mg 0.3 O 19 :3.5% Pr 3+ single crystal were investigated using x-ray and synchrotron radiation. The 4f5d states of Pr 3+ in these host lattices are at a higher energy than the 4f 2 [ 1 S 0 ] state. In the hexa-alu…
Crystals of Cu(II)(NO(3))(2)(pm)(3) (1), and two crystalline forms of Cu(II)(NO(3))(2)(H(2)O)(2)(pm)(2), (2) and (3), showed ferromagnetic, antiferromagnetic and paramagnetic interactions at extremely low temperatures, respectively. Crystal structure analyses revealed that the complexes were catena-dinitrato[mu-pyrimi…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTTransmission Electron Microscopy Observations on Lamellar Melting of Cold-Crystallized Isotactic PolystyreneTianxi Liu, Juergen Petermann, Chaobin He, Zhehui Liu, and Tai-Shung ChungView Author Information Advanced Polymers and Chem…
It was shown that axial pressure strongly changes the dielectric and ferroelectric properties of Na0.5Bi0.5TiO3 ceramic. This includes: (i) the shift of rhombohedral–tetragonal phase transition to higher temperature, suppressing the dielectric dispersion, and reduction of thermal hysteresis of the electric permittivit…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTTrap State Emission from TiO2 Nanoparticles in Microemulsion SolutionsHirendra Nath Ghosh and Soumyakanti AdhikariView Author Information Radiation Chemistry & Chemical Dynamics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India Cite this: Langmuir 2001, 17…
Poly(styrenesulfonate) (PSS) was adsorbed reversibly from aqueous CsCl or NaCl solutions onto oppositely charged DODAB (diocatadecyldimethylammonium bromide) monolayers at the water surface. By adjusting the DODAB lateral density, the surface charge of the liquid interface is varied. The electron density profile of th…
Three-dimensional superlattices forming films oriented along the substrate and dots deposited on a film made of 8 nm cobalt nanocrystals have been fabricated. The magnetic properties of such artificial structures are compared.
Four novel low-spin bis(amine) Co(III) porphyrins [Co(TPP)(BzNH(2))(2)](SbF(6)), 1, [Co(TPP)(1-BuNH(2))(2)](SbF(6)), 2, [Co(TPP)(PhCH(2)CH(2)NH(2))(2)](SbF(6)), 3, and [Co(TPP)(1-MePipz)(2)](SbF(6)), 4, have been synthesized and characterized by low-temperature X-ray crystallography, IR, electronic, and NMR ((1)H, (13…
We analyze a self-consistent theory of crack growth controlled by a cumulative damage variable d(t) dependent on stress history, in the quasistatic regime where the sound wave velocity is taken as infinite. Depending upon the damage exponent m, which controls the rate of damage dd/dt~sigma(m) as a function of local st…