Materials Literature
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Mesoscopic simulation techniques are employed to investigate lamellar orientation in block copolymers subjected to oscillatory shear. Dynamic mean-field density functional theory (MesoDyn) is able to capture parallel lamellar and perpendicular lamellar states at low and higher shear rates. At higher shear rates a thir…
Three thermoplastic polyurethanes (TPUs) containing different hard/soft (h/s) segment ratios (1.05-1.4) were prepared using the prepolymer method. MDI (diphenylmethane-4,4′diisocyanate) and polyadipate of 1,4-butanediol (M w = 2440) were allowed to react to produce the prepolymer. To provide the polyurethanes with hig…
We consider an Allen–Cahn/Cahn–Hilliard system with a non‐degenerate mobility and (i) a logarithmic free energy and (ii) a non‐smooth free energy (the deep quench limit). This system arises in the modelling of phase separation and ordering in binary alloys. In particular we prove in each case that there exists a uniqu…
Nanosized Ti-UVM-7 materials with a hierarchical system of pores at two different length scales have been prepared through a one-pot procedure by using a simple template agent; the catalytic activity and selectivity of the resulting materials in bulky olefin epoxidation by organic peroxides are the highest reported to…
Pale yellow (AgI)2Ag3SbS3 was synthesized by the reaction of stoichiometric amounts of AgI and Ag3SbS3 (2 ∶ 1) at 683 K. It is air stable for several months. The crystal structure was determined at different temperatures in the range from 173 K to 573 K by single crystal X-ray diffraction. (AgI)2Ag3SbS3 crystallizes i…
A 27-m-long drilled core taken from Lake Cuitzeo, central Mexico, preserves a late Quaternary paleoenvironmental record of the center of the lake. Radiocarbon dating of the upper third of the core indicates an age of about 42,000 yr B.P.; an extrapolation of sedimentation rates from the upper part of the core suggests…
Magnetic resonance imaging (MRI) has evolved into a sophisticated, noninvasive imaging modality capable of high-resolution anatomical and functional characterization of transgenic animals. To expand the capabilities MRI, we have developed a novel MR signal amplification (MRamp) strategy based on enzyme-mediated polyme…
Spectroscopic, electrochemical and fluorescence properties of five octahedral tin(IV) porphyrins ([( TpTP ) Sn ( O -m,p- C 6 H 3 ( CH 3 ) 2 ) 2 ] (1), [( TpTP ) Sn ( O -p- C 6 H 4 ( CH 3 )) 2 ] (2), [( TpTP ) Sn ( O - C 6 H 5 ) 2 ] (3), [( TpTP ) Sn ( O -p- C 6 H 4 O -o,p- C 6 H 3 ( NO 2 ) 2 ) 2 ] (4) and [( TpTP ) Sn…
Comparison of the ultrastructure of the hyaline tissue of conodont elements and the enamel of vertebrates provides little support for a close phylogenetic relationship between conodonts and vertebrates. Transmission and scanning electron microscopy shows that the mineralised component of the hyaline tissue of Panderod…
Absorption of far-infrared (FIR) radiation and Raman scattering in CdTe nano-crystals (spherical quantum dots (QDs) of several nanometers in size) and Cd54Te32(SCH2CH2OH)8–32 clusters prepared by colloidal synthesis were studied. Raman spectra of both QDs and clusters are dominated by a peak situated slightly below th…
A mathematical model was developed to describe the populations of polymer chains containing different numbers of long-chain branches (LCBs) made with a combination of two single-site catalysts. One of the catalysts produces only linear chains (linear-catalyst) and the other produces linear and long-branched chains (LC…
Investigating polarization loops of ferroelectric capacitors using a Sawyer-Tower test circuit may lead to some difficulties. It is indeed well-known that the plot of D-E loops may be subject to strong deformations hindering the ferroelectric polarization due to switching domains and preventing the accurate evaluation…
Ti–Cr–V alloys have a higher protium (hydrogen atom) desorption capacity, but a larger hysteresis in the absorption and desorption processes than AB2 and AB5 type protium absorption alloys. It is desirable that the alloys have a smaller hysteresis for the use of hydrogen storage tanks. This paper aims to clarify the e…
Kiritani et al. have observed a large number of small vacancy clusters without dislocations at the tip of torn portions of fcc metals such as Au, Ag, Cu and Ni. Small vacancy clusters, rather than dislocation cell structures, have also been observed after high-speed compressive deformation, suggesting the possibility…
Characterization of the racemic species, which can be a racemic compound, a racemic conglomerate, or a pseudoracemate (solid solution), is a prerequisite for the design of crystallization resolution processes. It is useful to determine the solid/liquid equilibrium solubility of the enantiomer mixtures for crystallizat…
A series of poly(DL-lactide) grafted gelatins, as new bioabsorbable amphiphilic polymers useful in parenteral drug delivery systems and in tissue engineering, were synthesized by the ring opening polymerization of DL-lactide onto a fractionated gelatin with the molecular weight of 1.02 x 10(5). Using tin(II) bis(2-eth…
The influence of hydrogen in Fe, 301 stainless steel (SS 301), and Avesta 353MA on corrosion resistance in aqueous solutions was studied. The oxidation kinetics of uncoated and Pt-coated Fe was also investigated in at 500 and 700°C. Electrochemical and weight loss measurements were used to evaluate the corrosion resis…
Temperature dependence of electric permittivity, pyroelectric current, piezoelectric coefficients (d 33 and d 31 ) and electromechanical coupling factors (k 33 and k 31 ) of (Na 0.5 Bi 0.5 ) 0.86 Ba 0.14 TiO 3 single crystal have been measured. The presented crystal exhibits diffuse phase transition, ferroelectric pro…
We use ab initio Quantum Mechanical (QM) calculations to derive a force field that accurately describes the atomic interactions in BaTiO3 allowing, via Molecular Dynamics (MD), the simulation of thousands of atoms. A key feature of the force field (denoted ReaxFF) is that charge transfer and atomic polarization are tr…
Transition metal complexes encompass a unique pool of building blocks with diverse stereochemical, electrochemical and photophysical features. Despite the current interest in employing polypyridine-containing coordination compounds for the fabrication of functional assemblies, their full potential as synthetic buildin…