Materials Literature
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Novel photoresponsive nanogels were prepared by the self-assembly of spiropyrane-bearing pullulan (SpP). The solution properties of the nanogels could be controlled by photostimulation via isomerization between hydrophobic spiropyrane and hydrophilic merocyanine. The molecular chaperone-like activity of the nanogels i…
We present results of correlated pseudopotential calculations of an exciton in a pair of vertically stacked InGaAs/GaAs dots. Competing effects of strain, geometry, and band mixing lead to many unexpected features missing in contemporary models. The first four excitonic states are all optically active at small interdo…
A method to reconstruct weakly anisotropic inhomogeneous dielectric tensors inside a transparent medium is proposed. The mathematical theory of Integral Geometry is cast into a workable framework which allows the full determination of dielectric tensor fields by scalar Radon inversions of the polarization transformati…
Time-domain THz transmission experiment was performed on a $\rm SrBi_2Ta_2O_9$ film deposited on sapphire substrate. Temperatures between 300 and 923 K were investigated and complex permittivity spectra of the film were determined. The lowest frequency optic phonon near 28 cm$^{-1}$ reveals a slow monotonic decrease i…
We report on observation of a light-induced switching of the conductance in the back-gated organic field-effect transistors (OFETs) with built-in conduction channel. In the studied devices, the built-in channel is formed owing to the self-sensitized photo-oxidation of rubrene surface. In the dark, the back gate contro…
A brief introduction is given to Kinetic Monte Carlo (KMC) simulations of epitaxial crystal growth. Molecular Beam Epitaxy (MBE) serves as the prototype example for growth far from equilibrium. However, many of the aspects discussed hear would carry over to other techniques as well. A variety of approaches to the mode…
Poly(glycolic acid) (PGA) has a long history as a bioresorbable polymer. Its biocompatibility is widely accepted, yet PGA is often rejected as a soft-tissue scaffold because of fibrous encapsulation. The goal of this study was to improve the soft-tissue biocompatibility of PGA by producing scaffolds composed of small-…
A novel nonaqueous route for the preparation of nanocrystalline BaTiO(3), SrTiO(3), and (Ba,Sr)TiO(3) has been developed. In a simple one-pot reaction process, the elemental alkaline earth metals are directly dissolved in benzyl alcohol at slightly elevated temperatures. After the addition of Ti(O(i)Pr)(4), the reacti…
We have developed an analytical method to determine the coefficient of thermal expansion (CTE) for single wall carbon nanotubes (CNTs). We have found that all CTEs are negative at low and room temperature and become positive at high temperature. As the CNT diameter decreases, the range of negative CTE shrinks. The CTE…
Because of the high affinity of the carbonate ion (CO 3 2 - ) to the hydrotalcite-like compounds or LDHs (layered double hydroxides), it was difficult to deintercalate carbonate ions and convert them into other LDHs with an easier anion-exchangeability. By treatment with dilute acids such as HCl, the conversion is lim…
Spin-polarized density functional theory has been used to study the properties of vacancies in a graphene sheet and in single-walled carbon nanotubes (SWNTs). For graphene, we find that the vacancies are magnetic and the symmetry of the sheet is broken by the distortion of an atom next to the vacancy site. We also stu…
Owing to their superior mechanical and physical properties, carbon nanotubes seem to hold a great promise as an ideal reinforcing material for composites of high-strength and low-density. In most of the experimental results up to date, however, only modest improvements in the strength and stiffness have been achieved…
When used as fillers in polymer composites, the thermostability of cellulose crystals is important. Sulfate groups, introduced during hydrolysis with sulfuric acid, are suspected to diminish the thermostability. To elucidate the relationship between the hydrolysis conditions, the number of sulfate groups introduced, a…
Abstract Danish district heating (DH) systems utilise water with unique characteristics that include low conductivity, high pH, nutrient poor and anaerobic (oxygen free) conditions in order to reduce corrosion rates. This survey was carried out in order to investigate the potential for biofilm formation and biocorrosi…
Abstract We studied mechanical deformations induced when an insulating material was subjected to a gradual increase in a direct‐current electric field. Poly(ethylene terephthalate) film was studied with an optical technique, which was nondestructive and involved no physical contact. The experimental results indicated…
Abstract Filamentous green algae, Cladophora glomerata, obtained from rivers and streams in California was used as a filler in isocyanate‐based foams. Up to 40 wt % dried and chopped algal fibers were added to the isocyanate–polyol mix. The algal fibers and foam samples were examined by scanning electron microscopy. T…
Abstract Titanium is the best metal for making dental implants and restorations. In the last decade, new titanium alloys have been developed in different areas of dentistry. Concurrently, treatments using fluoride supplementation, such as odontology fluoride containing gels, have also been widely used in odontology. T…
${\mathrm{La}}_{2}$, ${\mathrm{Yb}}_{2}$, and ${\mathrm{Lu}}_{2}$ have been studied by use of the density-functional methods B3LYP, BLYP, B3PW91, BHLYP, BP86, B3P86, MPW1PW91, and PBE1PBE. In these density-functional methods, the exchange functional is from either Becke's three-parameter HF-DFT hybrid exchange functio…
Using the first-principles real space DMOL3 method, we investigate the electronic structure of C doped at different types of interstitial sites in the [100](010) edge dislocation core of bcc Fe. Our energetic calculations show that C has a strong segregation tendency to enter the expansion region, which is related to…
We performed ab initio, self-consistent calculations for the electronic structure of selected semiconducting carbon nanotubes in the symmorphic and nonsymmorphic groups. We employed a real space approach in the linear combination of atomic orbital formalism. We utilized a nonlocal density-functional potential in the g…