Materials Literature
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Abstract Grating waveguide couplers with a flat surface were fabricated in an azobenzene liquid‐crystalline polymer film by holographic lithography using Ar + laser beams at 488 nm. When a probe beam at 633 nm was incident to one grating of a grating waveguide coupler, the beam propagated in the waveguide and an outpu…
Alternatives to first-order model of death kinetics of microorganisms have been proposed as improvements in the calculation of lethality for a thermal process. Although such models can potentially improve predictions for many situations, this article tries to answer the question of whether the added complexities of th…
We report on magnetoconductance experiments in ballistic multiwalled carbon nanotubes threaded by magnetic fields as large as 55 T. In the high temperature regime (100 K), giant modulations of the conductance, mediated by the Fermi level location, are unveiled. The experimental data are consistently analyzed in terms…
Timed release. An AB3 self-immolative dendron has been used as a platform for the controlled release of peptide nanotubes. The enzyme penicillin G amidase triggers the release, and the self-assembled peptide is simple diphenylalanine.
Soft X-Ray microscopy is used for the quantitative analysis of temperature-sensitive hollow polyelectrolyte microcapsules made of poly(sodium styrene sulfonate) and poly(diallyl dimethyl ammonium chloride) (see figure). Upon heating to 90 °C they shrink and the polymer membrane becomes denser. The analysis of such sys…
The corrosion resistance of titanium and its alloys is a desirable property for many applications in materials science. In this report, the properties of the passive oxide film (TiO 2 ) were examined by scanning electrochemical microscopy (SECM). A homemade closed-loop scanning electrochemical microscope was used to s…
By gradually decreasing the Pd concentration on Au nanoparticles from complete to incomplete surface coverage, in which well-dispersed nanoparticles are eventually obtained on the Au, we have demonstrated that the electrochemical response of hydrogen at Pd is critically dependent on the size and structure of the Pd su…
Phenomenological theory of dissipation-limited motion of ferroelectric domain walls under external bias field is applied to the case of 90-degree domain wall in a defect-free BaTiO3 crystal. Quantitative estimation for the limiting mobility (μE∼ 5 × 10− 4 m2/Vs at room temperature) is obtained in the framework of Land…
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…