Materials Literature
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Abstract Alkoxylation of epoxidized polyisoprene catalyzed by cerium ammonium nitrate (CAN) was achieved under very mild conditions both in melt and in solution. The cleavage of the epoxidized units with alcohols leads to the formation of alkoxyalcohol units and epoxide rearrangement units in the case of 20 and 38 % e…
The magnetic and transport behaviours of the La 0.7− x Gd x Sr 0.3 MnO 3 (0⩽ x ⩽0.70) system are investigated. The experimental results indicate that with increasing Gd doping content, the magnetism of the system changes from the long-range ferromagnetic order state to the cluster-spin glass state, then to the antifer…
Abstract Summary: The thermodynamic equilibrium in a melt of homopolymer C mixed with clay modified by a diblock copolymer AB is considered in theory. It is assumed that mixing is carried out in two stages. At first, the diblock copolymer penetrates into the interlayers formed by long clay sheets. Then, the clay with…
Two homologous mesogenic series, the ethoxyethyl 4-(4′-n-alkoxyphenylazo)benzoates (I) and the ethoxyethyl [4-(4′-n-alkoxybenzoyloxy)phenylazo]-4″-benzoates (II), both containing a terminal ethoxyethyl chain, have been synthesized. In series I, all nine members synthesized exhibit only an enantiotropic smectic A mesop…
Abstract No abstracts.
A simple spectrophotometric method, based on the complexes with xylenol orange (XO) and EDTA, is presented for the rapid determination of aluminium and nickel, respectively, in synthetic samples of hydrotalcite. The method only requires the solubilization in sulphuric acid of the inorganic material before the ligand a…
A chemical derivatization technique was used to control the pretilt angle of a liquid crystal. A polyvinyl alcohol (PVA) alignment layer, which gives a very low pretilt angle when in contact with the liquid crystal (LC), was reacted with trifluoroacetic anhydride (TFAA) in the gas phase to change polar –OH groups to –…
We present a numerical study of the neutral oxygen defects in silica. This work was performed using two complementary approaches: molecular dynamics using an empirical potential and ab initio calculations. We show that the formation energy fluctuates from point to point. The dispersion is due to the fluctuations of th…
Abstract Ring‐opening polymerization of D,L ‐lactide (LA) has been successfully carried out by using rare earth 2,6‐dimethylaryloxide (Ln(ODMP) 3 ) as single component catalyst or initiator for the first time. The effects of different rare earth elements, solvents, monomers and catalyst concentration as well as polyme…
We have numerically investigated the vibrational spectra of amorphous single-component clusters for several types of interactions among the particles. For all the potentials we have studied, we find that the density of states can be described, except at the two ends of the spectrum, by the same functional form to a ve…
Quantum confinement properties in silicon nanostructures are studied in silicon oxide and silicon nitride films at the amorphous/crystalline transition. The silicon cluster state is controlled with the annealing temperature. In both amorphous and crystalline structures, an intense luminescence is observed in the visib…
New dual mesogens, with α-methylstilbene and p-substituted azobenzene as main chain and side chain, respectively, and containing liquid crystalline polyphosphates, were synthesized. The pendant azobenzene units were unsubstituted or substituted with F, Cl, and Br atoms. All the polymers were synthesized by solution po…
The synthesis and characterization of single-wall carbon nanotubes (SWNTs) from simple catalytic precursors at 900 °C from methane and hydrogen is demonstrated. The catalyst precursor is comprised of iron nitrate and a commercially available siloxane polymer solution and is applied to various substrates via spin coati…
Models of Fe−zeolites have been used to study the dissociation of N 2 O, with and without the presence of ammonia. From Density Functional Theory calculations, the mechanism and energetics of N 2 O decomposition paths are presented and discussed. The influence of ammonia is analyzed. The results obtained for a single…
According to the group representation theory, we derive the character formulae of representation-matrices of the physical property tensors for the one-dimensional (1D) quasicrystals. Based on this, we have calculated the numbers of independent components of representation-matrices for thermal expansion coefficient ten…
Six series of new liquid crystalline materials with an azo group (N=N) located in different parts of the mesogenic core of the molecule have been synthesized and their physical properties studied. The chiral segments of these materials are based on alkoxypropionate or alkyllactate units. It has been found that lateral…
Abstract Summary: Degradation of a polymer in a reactor by the degrading agent(s) follows a distinct pattern, primarily influenced by structural integrity and reactor environment. This distinct pattern is recorded in the changes in the evolved molecular weight distribution (MWD) or polymer chain length distribution (P…
In Part II of this two-part study, system simulations and experimental correlations of a Shape Memory Alloy (SMA) based vibration isolation device (briefly described in Part I) has been presented. This device consists of layers of preconstrained SMA tubes undergoing pseudoelastic transformations under transverse dynam…
Particulate drug carriers offer unique opportunities to improve tumor therapy through several different mechanisms. Liposomes may (1) assist in formulation of poorly-soluble therapeutic agents, (2) provide a slow-release vehicle to achieve pharmacokinetic profiles that maximize the therapeutic index, or (3) behave as…
In this work, the effect of pseudoelastic response of shape memory alloys (SMAs) on passive vibration isolation has been investigated. This study has been conducted by developing, modeling, and experimentally validating a SMA-based vibration isolation device. This device consists of layers of preconstrained SMA tubes…