Materials Literature
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Band gaps in polythiophene ( T ) and the related polymers with a fused benzene ring ( TB, polythieno[3,4- b ]benzene) or a fused pyrazine ring ( TN, polythieno[3,4- b ]pyrazine) have been computed using a variety of methods. Geometries of oligomers up to octamers (AM1) and up to tetramers (B3LYP/6-31G*) have been opti…
The new reduced K 2 NiF 4 Co(II) phase, LaSrCoO 3.5 - x, is prepared by reduction of the Co(III) containing LaSrCoO 4 using H 2 gas and the new hydride solid−solid reduction methods. The hydride route is superior in both crystallinity and control of phase purity and allows access to reduced phases containing substanti…
The mechanical properties of cross-linked edible films based on calcium caseinate and two type of whey proteins (commercial and isolate) were investigated. Cross-linking of the proteins was carried out using thermal and radiative treatments. Size-exclusion chromatography performed on the cross-linked proteins showed t…
We formulate ten questions, covering outstanding aspects of the phenomenology of glassforming liquids, which we believe must be properly answered by any successful theory of structural glassformers. The questions range across thermodynamic, mass transport and vibrational dynamics phenomena. While these questions will…
An efficient approach to the syntheses of amphiphilic rod−coil diblock and coil−rod−coil triblock copolymers was developed. Each diblock copolymer consists of a perfectly monodispersed oligo(phenylene vinylene) covalently bonded to a poly(ethylene glycol) block with a very low polydispersity (<1.05). The structure and…
Computer simulations have been employed in recent years to evaluate the configurational entropy changes in model glass-forming liquids. We consider two methods, both of which involve the calculation of the `intra-basin' entropy as a means for obtaining the configurational entropy. The first method involves the evaluat…
This paper gives an introduction to and brief overview of some of our recent work on the equilibrium thermodynamics of glasses. We have focused on first-principles computations for simple fragile glasses, starting from the two-body interatomic potential. A replica formulation translates this problem into that of a gas…
The scaling laws describing the roughness development of crack surfaces are incorporated into the Griffith criterion. We show that, in the case of a Family-Vicsek scaling, the energy balance leads to a purely elastic brittle behavior. On the contrary, it appears that an anomalous scaling reflects a R-curve behavior as…
Corrections to the atomic orbital sum rule for circular magnetic x-ray dichroism in solids are derived using orthonormal LMTOs as a single-particle basis for electron band states.
Strategies for searching the space of variables in combinatorial chemistry experiments are presented, and a random energy model of combinatorial chemistry experiments is introduced. The search strategies, derived by analogy with the computer modeling technique of Monte Carlo, effectively search the variable space even…
Single-layer atom or vacancy clusters in the presence of electromigration are studied theoretically assuming an isotropic medium. A variety of distinctive behaviors distinguish the response in the three standard limiting cases of periphery diffusion (PD), terrace diffusion (TD), and evaporation-condensation (EC). A ge…
Within the framework of the mode coupling theory (MCT) of structural relaxation, mechanisms and properties of non-ergodicity transitions in rather dilute suspensions of colloidal particles characterized by strong short-ranged attractions are studied. Results building on the virial expansion for particles with hard cor…
The first X-ray magnetic circular dichroism (XMCD) spectra on the title compounds are presented. In Mn12 the Mn(III) and Mn(IV) contributions are clearly apparent and evidence the opposite spin arrangement of the two ions. For Fe8 the typical two peak structure of Fe(III) compounds is found. Quantitative analysis yiel…
The magnetic behaviour of nanoparticles of antiferromagnetic ferritin, with a mean Fe loading of 410 atoms per core, has been investigated by 57Fe Mossbauer absorption spectroscopy down to very low temperature (34mK). In previous experi- ments of frequency dependent magnetic susceptibility and magnetic noise performed…
In this paper, we discuss theoretically the behaviour of the four-point non-linear susceptibility and its associated correlation length for supercooled liquids close to the mode-coupling instability temperature T c . We work in the theoretical framework of the glass transition as described by mean-field theory of diso…
This paper describes the synthesis of both soluble and insoluble polymer-supported chiral (salen)Mn complexes and their use in asymmetric epoxidation reactions. These studies were undertaken to establish whether high enantioselectivities could be achieved with a polymer-bound catalyst and if the complexes could be rec…
A novel photoluminescence is reported for small metal nanocrystals in the near-infrared region (1.1−1.6 μm). Near-infrared photoluminescence spectra were measured at room temperature for 1.1 and 1.7 nm Au nanocrystals using a 1.06 μm excitation source. This photoluminescence is attributed to sp to sp-like transitions,…
We demonstrate a novel preparation method for the formation of metallic nanowires from gold, platinum, and silver using mesoporous silica SBA-15 as a template. SBA-15 controls the size and the growth direction of the nanowires and also prevents bulk aggregation of the metal. Nanowires can be isolated from the silica f…
The resistivity and volume expansion of carbon black (CB)/high-density polyethylene (HDPE) composite with different CB volume fractions at different temperatures were measured simultaneously. A model based on Meyer's theory is proposed to explain the positive temperature coefficient resistance (PTCR) effect. The relat…
The origins of the single- and double-melting endotherms of isotactic polypropylene crystallized at different temperatures were studied carefully by differential scanning calorimetry, wide-angle X-ray diffraction, and small-angle X-ray scattering. The experimental data show that spontaneous crystallization occurs when…