Materials Literature
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Nanocrystalline barium titanate (BaTiO 3 , BT) was synthesized hydrothermally at 220°C by reacting barium hydroxide with titanium dioxide. The resulting BT nanopowders were characterized by X‐ray diffraction (XRD), selected area electron diffraction (SAED), Raman spectrum, scanning electron microscopy (SEM), and high‐…
The effects of 10 paramagnetic metal complexes (Fe(III)EDTA(H2O)-, Fe(III)EDTA(OH)2-, Fe(III)PDTA-, Fe(III)DTPA2-, Fe(III)2O(TTHA)2-, Fe(III)(CN)6(3-), Mn(II)EDTA(H2O)2-, Mn(II)PDTA2-, Mn(II)beta-EDDADP2-, and Mn(II)PO4(-)) on F- ion 19F NMR transverse relaxation rates (R2 = 1/T2) were studied in aqueous solutions as…
Hybrid polyoxometalates (POMs) [AsW15Mo3S4(H2O)3O53]9− and [AsW15Mo3O2S2(H2O)3O53]9− in which a chalcogenide cluster unit is incorporated into a classical POM structure have been prepared and characterized by X-ray analysis and 183W NMR spectroscopy. The structure of the former can be derived from that of [H2AsW18O60]…
We aim to understand the effect of plastic deformation on the structure of a polymer glass. For that purpose, we measured by neutron scattering the structure of a polymethylmethacrylate (PMMA) sample stretched both below T g ( T g − 26 K) and above T g ( T g + 30 K) over a large length scale range. We observed that th…
Purpose The purpose of this paper is to synthesise high‐purity 9,9‐bis(4‐hydroxyphenyl)‐fluorene (BHPF). Design/methodology/approach 9,9‐bis(4‐hydroxyphenyl)‐fluorene was prepared from phenol and fluorenone using cationic ion‐exchange resin as the condensation catalyst. The purity and chemical structure of the resulti…
Abstract A sol–gel process has been developed to prepare polyimide (PI)/Al 2 O 3 hybrid films with different contents of Al 2 O 3 based on pyromellitic dianhydride (PMDA) and 4,4′‐oxydianiline (ODA) as monomers. FESEM and TEM images indicated that Al 2 O 3 particles are relatively well dispersed in the polyimide matri…
In this paper, a semi-analytical method is developed to compute the elastic stiffness of nanostructures such as nanowires, nanotubes and nanofilms. Compared with existing methods for such computations, this new method is more accurate and significantly reduces the computational time. It is based on the Taylor series e…
Three different kinds of pure-phase nanowires of Ln 2 O 2 S, Ln 2 O 2 S 2, and LnS 2 with diameters of several tens of nanometers, ∼20 nm for the La-series and ∼30 nm for the Nd-series, and lengths of up to several micrometers have been successfully converted from the same starting Ln(OH) 3 (Ln = La or Nd) nanowires v…
Hierarchical nanocomposite films with Pd-PdO nanoparticles anchored uniformly on the inner surface of TiO2 nanotubes were achieved through a stepwise bioredox/artificial oxygenation approach by using the natural eggshell membrane (ESM) as a template. The Pd content ratio of Pd-PdO loading could be arbitrarily varied f…
In this paper we investigate the transient behavior of a simple active catheter: a central tube actuated by a single nitinol tendon enclosed by an outer sleeve. Dynamic models are developed to characterize the transient behavior and optimize the design of an experimental prototype. The bending mechanics are derived us…
The metamaterials exhibiting negative permittivity and permeability that have been under numerical and experimental study recently generally operate at frequencies between the homogeneous $(\ensuremath{\lambda}\ensuremath{\gg}\text{period})$ and heterogeneous $(\ensuremath{\lambda}\ensuremath{\approx}\text{period})$ r…
The temperature dependence of $1∕f$ noise in individual semiconducting carbon nanotube (CNT) field-effect transistors is used to estimate the distribution of activation energies of the fluctuators $D(E)$ responsible for the noise. $D(E)$ shows a rise at low energy with no characteristic energy scale, and a broad peak…
n-ZnO/p-Si hetero-junction light emitting diodes were fabricated using a metal organic chemical vapour deposition (MOCVD) technique. Room temperature (RT) photoluminescence (PL) spectrum showed an intense main peak at 377 nm and a weak deep-level emission. The I–V characteristics of the n-ZnO/p-Si hetero-junction show…
Nanocrystalline n -AlO(OH) (Disperal P2, Sasol) was investigated by means of the atomic pair distribution function (PDF). The PDF is derived from powder diffraction data, and an ideally resolved PDF is obtained from a synchrotron source which provides a large maximal scattering vector length Q max > 300 nm −1 . Here,…
A series of molecular dynamics simulations was performed on a bicrystal to which a fixed shear rate was applied parallel to the boundary plane. Under some conditions, grain boundary motion is coupled to the relative tangential motion of the two grains. In order to investigate the generality of this type of coupled she…
The valence state of Mn-doped BiFeO 3 –BaTiO 3 ceramics has been probed by soft X-ray absorption spectroscopy (XAS). Mn-doped BiFeO 3 –BaTiO 3 has valence states of Fe 3+ and Ti 4+ , although BiFeO 3 and Mn-doped BiFeO 3 have mixed valence states of Fe 2+ and Fe 3+ . The Mn 2p-XAS peak of Mn-doped BiFeO 3 –BaTiO 3 loc…
An amphiphilic Gemini-shaped hexa- peri -hexabenzocoronene ( 1 ) with azide functionalities self-assembles to form graphitic nanotubes whose interior and exterior surfaces can be post-functionalized by “click chemistry”. A click reaction of the nanotubes with bulky macromolecules such as a dendronized alkyne (G2-alkyn…
The role of vacancy clustering and acceptor activation on resistivity evolution in N ion-implanted $n$-type hydrothermally grown bulk ZnO has been investigated by positron annihilation spectroscopy, resistivity measurements, and chemical profiling. Room temperature $220\phantom{\rule{0.3em}{0ex}}\mathrm{keV}$ N implan…
Al 2 O 3 ceramic nano-particles, which were regarded as an inactive catalyst in the growth of carbon nanotubes in the past, have been prepared as the catalyst for single-walled carbon nanotube (SWCNT) growth using an alcohol chemical vapor deposition method. Dense SWCNTs have been successfully synthesized, indicating…
We report that orotidine 5‘-monophosphate decarboxylase (OMPDC) catalyzes exchange of the C-6 proton of uridine 5‘-monophosphate (UMP) for deuterium from solvent in D 2 O at 25 °C and pD 7.0−9.3. Kinetic analysis of deuterium exchange gives p K a ≤ 22 for carbon deprotonation of enzyme-bound UMP, which is at least 10…