Materials Literature
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Abstract Amorphous and crystallized poly( L ‐lactide) (PLLA) films are prepared by quenching and annealing at 140°C for 600 min, respectively, from the melt. Their hydrolysis is investigated at pH 2.0 in HCl and DL ‐lactic acid (DLLA) solutions (37°C) for up to 300 days, and the results are compared with those obtaine…
DFT calculations performed on Si_2H_6, Si_2F_6, Si_2Cl_6, and Si_2Br_6 are reported. The evolution of the energy, the chemical potential and the molecular hardness, as a function of torsion angle, is studied. Results at the DFT-B3LYP/6-311++G** level show that the molecules always favor the stable staggered conformati…
The low temperature magnetic properties of pyrochlore compound Dy2Ti2O7 in magnetic fields applied along the [111] direction are reported. Below 1 K, a clear plateau has been observed in the magnetization process in the field range 2~9 kOe, followed by a sharp moment jump at around 10 kOe that corresponds to a breakin…
A systematic ab-initio study within the framework of the local-spin-density approximation including spin-orbit coupling and an orbital-polarization term is performed for the spin and orbital moments and for the X-ray magnetic circular dichroism (XMCD) spectra in hcp Co, in a Pt supported and a free standing Co monolay…
Collision processes between two gold clusters are investigated using classical molecular dynamics in combination with embedded atom (EA) potentials, after checking the reliability of EA results by contrasting them with first principles calculations. The Au projectiles considered are both single atoms (N=1) and cluster…
We have performed a two-color time-resolved magneto-optical Kerr effect (MOKE) study of a ferromagnetic InMnAs/GaSb heterostructure. We observed ultrafast photo-induced changes in the MOKE signal induced by a large density of spin-polarized transient carriers created only within the InMnAs layer using intense 140 fs m…
We report the modifications of the microscopic dynamics of a colloidal glass submitted to shear. We use multispeckle diffusing wave spectroscopy to monitor the evolution of the spontaneous slow relaxation processes after the samples have been submitted to various straining. We show that high shear rejuvenates the syst…
The present investigation examines the relationship between structural order, diffusivity anomalies, and density anomalies in liquid silica by means of molecular dynamics simulations. We use previously defined orientational and translational order parameters to quantify local structural order in atomic configurations.…
Molecular dynamics computer simulations are performed to study the structure and dynamical behavior of chloride and associated cations at the interfaces between aqueous solutions and portlandite (Ca(OH) 2 ), Friedel's salt ([Ca 2 Al(OH) 6 ]Cl·2H 2 O), tobermorite (Ca 5 Si 6 O 16 (OH) 2 ), and ettringite (Ca 6 [Al(OH)…
We present a method for fabricating anchored polymers with a gradual variation of grafting densities on solid substrates. The technique for generating such structures comprises (i) formation of a molecular gradient of polymerization initiator on the solid substrate and (ii) polymerization from the substrate-bound init…
Abstract The effect of the thermal history on the properties of welded high density polyethylene is studied. The lamellar microstructure observed in the weld is different from that in the bulk slow cooled material. The weld has lower crystallinity and smaller lamellar size, both of which change with annealing. The dif…
Abstract The applicability of poly(DL‐lactide‐co‐ϵ‐caprolactone) copolymers P(DL‐LA/CL) for controlled‐release devices was evaluated. The copolymers of DL‐lactide and ϵ‐caprolactone were polymerized in bulk using Sn(II)octoate as the initiator. The release of three model compounds, theophylline, propranolol hydrochlor…
A considerable number of new crystalline compounds were prepared by reacting L-arginine (L-Arg) with a series of inorganic and organic acids. In addition to the usual arginine slats with composition L-Arg-HX, where HX represents various acids, an entirely new class of crystal with the composition L-Arg 2HX was discove…
Abstract Several blends, covering the entire range of compositions, of a metallocenic ethylene‐1‐octene copolymer (CEO) with a multiphasic block copolymer, propylene‐ b ‐(ethylene‐ co ‐propylene) (CPE) [composed of semicrystalline isotactic polypropylene (iPP) and amorphous ethylene‐ co ‐propylene segments], have been…
Abstract Copolymers of ethylene glycol with 4,4′‐bibenzoic acid and terephthalic acid are known to crystallize rapidly to surprisingly high levels of crystallinity. To understand this unusual behavior, the isothermal crystallization of poly(ethylene bibenzoate‐ co ‐terephthalate) in the molar ratio 55:45 (PETBB55) was…
We vitrify dilute lithium chloride (LiCl) aqueous solutions (2.0–10.0 mol % solute) at about 0.5 GPa using a needle-type pressure device developed for cooling a liquid material rapidly, and measure Raman spectra of the vitrified solution at 1 atm and 25 K. The OH stretching vibrational modes of the vitrified solution…
Nd 0.7 Eu 0.3 NiO 3 thin films are deposited by rf sputtering and subsequent oxygen pressure annealing on (100) oriented silicon substrate. We characterize the thermochromic properties of films by measuring electrical transition, infrared transmittance, and reflectance. The thermochromic effect at room temperature is…
The dielectric permittivity and loss spectra of the glassy state of 5-methyl-2-hexanol obtained by quenching it from the liquid state has been studied. In one experiment, the spectra were studied at different temperatures as the quenched sample was heated at 0.1 K/min from 105.3 to 160.5 K. In the second experiment, t…
Carbon nanotips with a high-aspect ratio were directly grown on Pt films. Carbon nanotips grew up to 5.4 μm length and 64 nm diameter under a −120 V bias. Compared to the hollow structure of carbon nanotubes, transmission electron microscopy images indicate its solid body, which is made of graphite. Carbon nanotips po…
Abnormal anti-Stokes Raman scattering (AASR) was unambiguously observed in carbon nanotubes (CNT's). In contrast to traditional Raman scattering theory, the absolute value of the Raman frequency of the anti-Stokes peak is not the same as that of the corresponding Stokes peak. It was demonstrated that AASR scattering o…