Materials Literature
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A set of four porphyrin trimers ( 1 − 4 ) consisting of an energy-accepting 5,15-diphenylethynyl-substituted Zn(II)-porphyrin core flanked by two energy-donating peripheral Zn(II)-porphyrins have been prepared as a new efficient energy-transfer functional unit. The peripheral porphyrin donor is either a TPP-type Zn(II…
To investigate the structural and thermodynamic basis of the binding of solvent at internal sites within proteins a number of mutations were constructed in T4 lysozyme. Some of these were designed to introduce new solvent-binding sites. Others were intended to displace solvent from preexisting sites. In one case Val-1…
We synthesized new polyaniline (PANI)/organoclay (aminosilane surface-treated) nanocomposite particles and prepared electro-rheological (ER) fluids by dispersing the particles in silicone oil. A distinct enhancement in yield stress was observed due to the presence of PANI-coated clay particles. The effects of delamina…
We have presented polarized photoluminescence (PL) from photopatterned discotic liquid crystal (DLC) film. Photopatterned DLC film was accomplished by the photoalignment technique consisting of oblique photoirradiation with nonpolarized light and the subsequent annealing of an azobenzene-containing polymer thin film.…
Using a tunneling approach for the field emission from a single carbon nanotube, expressions for the emission current as a function of the anode voltage and of the emitted electron energy spectrum are obtained. The low dimensionality of the electronic system of a carbon nanotube is taken into account. The extraction f…
The SH3 domain of Eps8 was previously found to form an intertwined, domain-swapped dimer. We report here a monomeric structure of the EPS8 SH3 domain obtained from crystals grown at low pH, as well as an improved domain-swapped dimer structure at 1.8 A resolution. In the domain-swapped dimer the asymmetric unit contai…
Syntactic foam products are most often made from glass microballoons embedded in a thermosetting polymer matrix, and they have good mechanical and thermal properties. However, the glass microballoons easily break in shear and are therefore very difficult to use for manufacturing methods that cause shearing of the mate…
The melting and crystallization behavior of random propene/higher linear α-olefin copolymers synthesized with the catalyst system (CH3)2Si(2-methylbenz-[e]indenyl)2ZrCl2/MAO were investigated. According to Flory's theory, the melting point depression is linearly related to the amount of comonomer incorporated irrespec…
A streamlined synthetic scheme was developed for the preparation of a novel series of cationically polymerizable epoxy-functional organic−inorganic hybrid resins. The reaction sequence consists, first, of the regioselective rhodium-catalyzed monoaddition of an α,ω-Si−H difunctional siloxane to a vinyl epoxide. The sec…
The polarization switching in Pb(Zr,Ti)O3 (PZT) ferroelectric bulk ceramics undoped and doped with Nb2O5 or Fe2O3 was studied by means of both hysteresis loops and transient current measurements at room temperature. The results obtained revealed that in PZT ceramics, during the poling process, the reorientation of the…
This work deals with the use of clay as a filler in an intumescent EVA-based formulation using a charring polymer (polyamide-6) as a carbonization agent. Using PA-6 clay nanocomposite instead of pure PA-6 had been shown to improve the fire properties of the intumescent blend. In this study, using clay as a “classical”…
Piezoelectric properties of Pb 1- a Sr a (Ni 1/2 W 1/2 ) 0.02 (Mn 1/3 Nb 2/3 ) b (Zr x , Ti y ) 1-0.02- b O 3 ) ceramics, to which 0.5 wt% PbO, 0.3 wt% Fe 2 O 3 and 0.25 wt% CeO 2 were added, were investigated at different compositions of a =0–0.06, b =0.05–0.09, x =0.49–0.51, and y =0.49–0.51. In the ceramics with a…
Nanostructured hybrid organic-inorganic solids are a class of materials of growing interest because of their great potential in synthesis and possible applications. All organic molecules containing at least two −Si(OR)3 groups can be transformed by hydrolytic polycondensation at silicon into materials in which the −Si…
The binding energy of H to a (10,0) carbon nanotube is calculated at 24, 50, and 100% coverage using the AM1 and ONIOM approaches. Several different bonding configurations are considered for the 50% coverage case. Using the ONIOM approach, the average C−H bond energy for the most stable 50% coverage and for the 100% c…
The constitutive relation describing the optical response of dielectric crystals in incommensurately modulated phases is derived for the plane-wave range of modulation. The symmetry properties of modulation corrections to the permittivity tensor of such crystals are analyzed with allowance for spatial dispersion. Thes…
A numerical method for estimating the order of angular focusing, which is a most important parameter of electron-optical systems, is proposed. The method is based on the determination of the value of the correlation between a power function and a function of charged-particle entry angle, the latter being constructed b…
Almost all of the major advances in understanding the interaction of X-rays with crystalline matter were made in the early part of the 20th century. By the 1970s, every crystallography laboratory had a single-crystal diffractometer, and powder diffraction was the de facto standard method for phase identification in po…
Abstract The effect of dichlorocarbene modified styrene butadiene rubber (DCSBR) as a compatibilizer in blends of acrylonitrile butadiene rubber and styrene butadiene rubber (SBR/NBR) has been studied. The cure characteristics, physical properties, crosslink density, FTIR studies and low temperature transitions of the…
The synthesis and characterization of some polyesters containing azomethine linkages are reported here. The electrical conductivity of these polyesters is measured and the results are explained with simple Pariser-Parr-Pople calculations. The polymers are doped with Ag and the electrical conductivity of most of the do…
Abstract The spherulitic and lamellar morphologies of melt crystallized isotactic polypropylene (iPP) have been investigated according to various crystallization temperatures and times. In this study, an appropriate chemical etching condition for the observation of iPP morphology by scanning electron microscopy (SEM)…