Materials Literature
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Abstract Complex micelles with a P4VP core surrounded by a mixed PNIPAM/PEG shell were prepared by comicellization of PNIPAM 93 ‐ b ‐P4VP 58 and PEG 114 ‐ b ‐P4VP 58 in aqueous solutions. Increasing the temperature above the LCST of the PNIPAM induced a phase separation of the mixed shell due to the collapse of the PN…
The vibrational properties of adsorbed carbonyls on heterogeneous Pd/oxide systems (SiO 2 −Al 2 O 3, Al 2 O 3, and MgO) are compared and discussed. On the basis of the surface science literature, the complex IR spectra of carbonyls formed on Pd particles are interpreted in terms of what occurs on well-defined Pd(111)…
$\mathrm{Ti}\phantom{\rule{0.3em}{0ex}}K$ and $\mathrm{Ti}\phantom{\rule{0.3em}{0ex}}{L}_{2,3}$ x-ray absorption fine-structure near-edge spectra of ${\mathrm{SrTiO}}_{3}$ thin films grown coherently on $\mathrm{Si}(001)$ reveal the presence of a ferroelectric (FE) distortion at room temperature. This unique phase is…
We report experimentally and theoretically the converse magnetoelectric (CME) effect in a three-phase piezoceramic-metal-cap-magnet composite made by sandwiching a thickness-polarized Pb(ZrxTi1−x)O3 (PZT) disk between two truncated conical brass caps and two thickness-magnetized SmCo disks. The reported CME effect ori…
Abstract A new method is reported for minimizing the inherent fiber instability in the electrospinning process. The method, dubbed “biased AC electrospinning”, employs a combination of DC and AC potentials and results in highly‐aligned mats of polymer or composite polymer fibers. The relationship between specific proc…
The excess low-frequency normal modes for two widely used models of glasses are studied at zero temperature. The onset frequencies for the anomalous modes for both systems agree well with predictions of a variational argument, which is based on analyzing the vibrational energy originating from the excess contacts per…
Using a combination of ab initio band-structure methods and dynamical mean-field theory, we study the single-particle spectrum of the prototypical charge-transfer insulator NiO. Good agreement with photoemission and inverse-photoemission spectra is obtained for both stoichiometric and hole-doped systems. In spite of a…
We report on the resonant tunneling effect and the increase of tunneling magnetoresistance induced by it in ferromagnetic-semiconductor $\mathrm{GaMnAs}$ quantum-well (QW) heterostructures. The resonant tunneling effect was observed when the $\mathrm{GaMnAs}$ QW thickness was from 3.8 to $20\phantom{\rule{0.3em}{0ex}}…
To optimize the extraction of gelatin from channel catfish (Ictalurus punctatus) skin, a 2-step response surface methodology involving a central composite design was adopted for the extraction process. After screening experiments, concentration of NaOH, alkaline pretreatment time, concentration of acetic acid, and ext…
A concept of backward-wave bianisotropic composite medium matched to free space is suggested. It is based on the use of a uniaxial bianisotropic structure embedded into a matrix with negative effective permittivity. Since bianisotropy is easier to achieve in the optical range than artificial magnetism, this concept is…
The organic capping ligands used in the colloidal synthesis of CdSe nanorods have a profound impact on nanorod shape, dimensions, and capping structure as is shown here by varying the length of the alkylphosphonic acid ligands used in synthesis. The shorter the ligand, the more elongated and branched are the resulting…
Abstract Microporous organic polymers offer the possibility of storing hydrogen safely at low temperatures and moderate pressures via physisorption. A range of polymers of intrinsic microporosity (PIMs) have been studied. The best PIM to date is based on a triptycene monomer and takes up 2.7% H 2 by mass at 10 bar/77…
We are revisiting the efficiency problem of DKR nonradiative transitions at local electronic centers in polarizable solids. Following a brief survey, we formulate the general rate equations thereby defining the microscopic parameters controlling the nonradiative deexcitation. We also reproduce the quantum mechanical e…
In 1987-89 were synthesized soluble nano-composites of polyacetylene (NPA) with an abnormally high intensity of Raman scattering and high stability under laser radiation. Here we demonstrate that the key pre-condition to the outstanding characteristics of NPA is the vibrational and rotational mobility of nano-particle…
Alginate- (2% w/v) or gellan-based (0.5%) edible films, containing glycerol (0.6% to 2.0%), N-acetylcysteine (1%), and/or ascorbic acid (1%) and citric acid (1%), were formulated and used to coat fresh-cut apple and papaya cylinders. Water vapor permeability (WVP) was significantly higher (P < 0.05) in alginate films…
Abstract A tremendous effort has been made over the last decade to develop and test films with antimicrobial properties to improve food safety and shelf life. This review catalogues and analyses the outcome of these research efforts. The bacteriocin nisin was the antimicrobial most commonly incorporated into films, fo…
Density functional theory was employed to investigate the water-gas-shift reaction (WGS, CO+H2O-->H2+CO2) on Au29 and Cu29 nanoparticles seen with scanning tunneling microscopy in model AuCeO2(111) and CuCeO2(111) catalysts. Au(100) and Cu(100) surfaces were also included for comparison. According to the calculations…
We investigate contact angle hysteresis on chemically patterned and superhydrophobic surfaces, as the drop volume is quasistatically increased and decreased. We consider both two (cylindrical drops) and three (spherical drops) dimensions using analytical and numerical approaches to minimize the free energy of the drop…
Since approval of the first magnetic resonance (MR) contrast agent was granted in 1988, there has been remarkable growth in the utilization of intravenous gadolinium (Gd)-based agents. Currently it is estimated that nearly half of all MR studies performed are contrast-enhanced. Despite containing a toxic heavy metal,…
Nanoparticles exhibiting a cooperative spin transition, prepared using the reverse micelle technique, are reported. A 40 K magnetic hysteresis is observed near room temperature for [Fe(Htrz)2(trz)](BF4) nanoparticles (where trz is a triazole derivative) of 11 ± 5 nm in diameter. The figure shows the nanoparticles in o…