Materials Literature
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Crystalline solids are characterized by long-range positional and orientational order in three dimensions, whereas amorphous liquids lack long-range order in any dimension. Liquid crystals (mesophases) show structural, mechanical and optical properties intermediate to those of crystalline solids and the amorphous, liq…
The synthesis of amphiphilic macromolecules by amidation of hyperbranched polyethylenimine was studied. Amidation with palmitic acid or the methyl ester proceeds up to 84% degree of amidation (140 °C, vacuum). The primary amine end groups react preferentially. With carbonyldiimidazole (CDI)-activated acids nearly comp…
We have calculated the effect of hydrogen adsorption on the work function and surface relaxation of Ti (0001). Calculations were performed for 100% and 25% coverage of the fcc and hcp adsorption sites as well as 100% coverage of both sites. The average of the relaxations obtained with 100% occupation of the fcc or hcp…
Abstract The surface chemistry of hexagonal boron nitride powder is examined. Surface functional groups are found to consist of a mixture of primary and secondary amine groups as well as hydroxyl groups. The surface has a net basic character indicating that the amine contribution to the overall surface chemistry is gr…
Abstract The molecular structures and the spin ground‐state of the iron( ii/iii ) complexes Fe1 , Fe2 and Fe3 , which contain dianionic macrocyclic [N 4 ] ligands derived from substituted acetylacetaldehydes and 1,2‐diamines, have been investigated by X‐ray analysis and temperature‐dependent susceptibility measurement…
This manuscript reports the synthesis and the self-assembly of (4-3,4,5-3,5)nG2-CH2-Boc-l-Tyr-l-Ala-OMe dendritic dipeptides (n = 12, 16). These dendritic dipeptides self-assemble both in solution and in solid states into helical porous supramolecular columns that mimic porous transmembrane proteins. These supramolecu…
Relaxor ferroelectrics (RF) are characterized by diffuse ferroelectric transitions and high and frequency-dependent dielectric susceptibilities. Non-RFs show high dielectric responses only in the direct vicinity of the transition temperature whereas RFs exhibit high responses over a large temperature range. Despite th…
The compound AgBi 3 S 5 ( I ) (synthetic pavonite) and its solid solution AgSb x Bi 3 - x S 5 ( x = 0.3) ( II ) were prepared by direct combination of elemental Ag, Bi, Sb, and S. They crystallize in the monoclinic space group C 2/ m with a = 13.345(3) Å, b = 4.0416(8) Å, c = 16.439(3) Å, and β = 94.158(3)° for I and…
Frontier-orbital design aided in the preparation of the novel neutral linear chain rhodium(I,II) complex [Rh(3,6-dbdiox-4,5-Cl2)(CO)2]∞ (see picture), in which the mixed-valent state is formed by electron transfer between metal d and semiquinonate π* orbitals (3,6-dbdiox-4,5-Cl2: semiquinonate or catecholate of 3,6-di…
Mixtures of derivatives of Hanabusa's bolaamphiphilic amidocarbamates containing two Z-valinyl subunits and aliphatic spacers that range from ethylenic to octamethylenic are able to form organogels. A coassembly of them is observed in their acetonitrile and toluene gels; namely, the concentration of a given compound a…
The electrochemical reduction of tetrabutylammonium salts of isostructural pairs of polyoxometalates [Bu4N]2[M6O19], [Bu4N]4[alpha-SiM12O40], and [Bu4N]4[alpha-S2M18O62] (M = Mo or W) has been investigated at glassy carbon electrodes in dissolved and surface-confined states in ionic liquids and other media. In the ion…
[reaction: see text] A novel molecular switching system based on reactivity-gated photochromism operates because a butadiene undergoes a [4 + 2] cycloaddition reaction with a dienophile to produce the photoresponsive 1,2-dithienylethene backbone. The reversible change in color when samples are irradiated with appropri…
We propose a fast impurity solver for the general quantum impurity model based on the perturbation theory around the atomic limit, which can be used in combination with the local density approximation (LDA) and the dynamical mean field theory (DMFT). We benchmark the solver in the two band Hubbard model within DMFT ag…
We measure electrical transport on networks of single-wall nanotube ropes as a function of temperature T, voltage V, and pressure up to 22 GPa. We observe Luttinger liquid (LL) behavior, a conductance proportional to T(alpha), and a dynamic conductance proportional to V(alpha). With pressure, conductance increases whi…
Using the recent incremental modelling, it is shown that the trajectory of a sample in the phase space of soil mechanics in the vicinity of the critical state is not governed by the rigidity matrix, but by its variations. The characteristics are used to predict that pseudo Young modulus tends to 0 as B -M-1 tends to 0…
It is proposed a simple non linear incremental modelling of the axi-symmetric compression of granular materials and powders. It describes the main features of undrained compression and of oedometric compression using the results of compression tests at constant lateral stress . It generalises the concept of characteri…
Aging, which manifests itself as an irreversible increase in electrical resistance in island metal films is of considerable interest from both academic as well as applications point of view. Aging is attributed to various causes, oxidation of islands and mobility of islands followed by coalescence (mobility coalescenc…
We use an analogy with the statistical mechanics of gas to build the statistical mechanics of granular media. The case of an isotropic disordered packing of equal spheres submitted to an isotropic stress is considered. We use the assumption of a maximal disorder and the method of the Lagrange multipliers to demonstrat…
Kramers-Kronig type dispersion relations for integer powers of complex reflection coefficient are introduced for testing the consistency of terahertz reflection spectra. By using numerical simulations we show that such dispersion relations can be applied for distillation from data with some experimental artifacts with…
It is recalled that stress-strain incremental modelling is a common feature of most theoretical description of the mechanical behaviour of granular material. An other commonly accepted characteristics of the mechanical behaviour of granular material is the Rowe's relation which links the dilatancy K to the ratio B of…