Non-axisymmetric magnetostatic equilibrium with strong twisted component of magnetic field

The perturbation theory is applied further to the discussion of the equilibrium properties of a sunspot-like magnetic field with a strong twisted component. The basic state reduces to the usual one discussed extensively for the axisymmetric magnetostatic equilibrium with twisted component of magnetic field, and the perturbed state is described by two coupled equations. As the magnetic force-line is twisted, there is a magnetic tension in the azimuthal direction. In this case, the perturbed total pressure is no longer independent of the azimuthal variable θ, and the magnetic field in the dark penumbal fibril may be either stronger or weaker relatively.

Twisted duality symmetry and integrability of hybrid superstring on AdS(2) x S-2

IEECAS SKLLQG

Interdigited phospholipid/alkanethiol bilayers assembled on APTMS-supported gold colloid electrodes

The preparative procedure of a kind of phospholipid/alkanethiol bilayers on a planar macroelectrode was copied to the as-prepared gold colloid electrodes. The electrochemical and spectral results show that the bilayers on colloid electrodes are interdigited, which are different from their 2-D counterparts on a planar macroelectrode.

Stabilization of polymer bilayers by introducing crosslinking at the interface

Bisphenol A solid epoxy serves as an effective reaction compatibilizer to the bisphenol A polycarbonate (PC)/PMMA bilayer systems. Addition of epoxy to the bottom PMMA layer can retard or even prevent the dewetting of PC films by introducing crosslinking between both components at the interface. This is the first investigation of polymer bilayers stabilized by chemical reactions.

Surface and interface morphology of polystyrene/poly(methyl methacrylate) thin-film blends and bilayers

The surface and interface morphologies of polystyrene (PS)/poly(methyl methacrylate) (PMMA) thin-film blends and bilayers were investigated by means of atomic force microscopy (AFM) and X-ray photoelectron spectroscopy. Spin-coating a drop of a PS solution directly onto a PMMA bottom layer from a common solvent for both polymers yielded lateral domains that exhibited a well-defined topographical structure. Two common solvents were used in this study. The structure of the films changed progressively as the concentration of the PS solution was varied. The formation of the blend morphology could be explained by the difference in the solubility of the two polymers in the solvent and the dewetting of PS-rich domains from the PMMA-rich phase. Films of the PS/PMMA blend and bilayer were annealed at temperatures above their glass-transition temperatures for up to 70 h. All samples investigated with AFM were covered with PS droplets of various size distributions. Moreover, we investigated the evolution of the annealed PS/PMMA thin-film blend and bilayer and gave a proper explanation for the formation of a relatively complicated interface inside a larger PS droplet.

Interaction of scopolamine and cholesterol with sphingomyelin bilayers by FT-Raman spectroscopy

The interaction of scopolamine and cholesterol with sphingomyelin bilayers has been investigated by FT-Raman spectroscopy in head-group region (600-1000 cm(-1)), the C-C stretching (1000-1200 cm(-1)), CH2 deformation (1400-1500 cm(-1)) and the C-H stretching (2800-3000 cm(-1)) mode regions. The results indicate that scopolamine and cholesterol do not change the conformation of O-C-C-N+ backbone in the choline group of sphingomyelin bilayers, the polar headgroup is still extending parallel to the bilayer surface and O-C-C-N+ group is still in its gauche conformer. Scopolamine and cholesterol lower the order of the interface, the interchain, CH2 crystal lattices and the lateral chain-chain packing, and increase their fluidity.

Paint-freeze method to form self-assembled alkanethiol/phospholipid bilayers on gold

A paint-freeze method for preparing self-assembled alkanethiol/phospholipid bilayers on a gold surface has been described (by cyclic voltammetry, a.c impedance, polarized FTIR-ATR) to be well-ordered and packed, stable, solvent-free bilayers. The lipid order parameter was 0.67, calculated from the dichroic ratio, consistent with a well-ordered lipid film in which the methylene groups have segmental flexibility and are disordered to a degree which is typical for a lipid bilayer in the liquid-crystalline phase. Such a supported membrane provides a useful way for studies in biophysics, physiology and electrochemistry.

Compensation effect of polyimide thin films on normally white twisted nematic liquid crystal displays

The disadvantages of Normally White Twisted Nematic Liquid Crystal Display (NW-TN-LCD) were discussed. The reason that the negative birefringent polyimide thin films were used to compensate NW-TN-LCD to decrease off-axis leakage, improve contrast ratios and enlarge viewing angles was explained in this paper. A certain polyimide thin film was taken as an example to show compensation effect on NW-TN-LCD.

K+ sensors based on supported alkanethiol/phospholipid bilayers

A novel kind of K+ sensor with valinomycin-incorporated bilayers supported on a gold electrode consisting of self-assembled alkanethiol monolayers (SAMs) and a lipid monolayer has been fabricated successfully. The lipid monolayer is deposited on the alkylated surface of the first alkanethiol monolayer through three different methods, such as the Langmuir-Blodgett (LB) technique, painted method and painted-frozen method. The response of K + sensors produced by a painted or painted-frozen lipid monolayer on an alkanethiol alkylated gold electrode is larger than that by the LB method, which is due to the difference in fluidity of the three kinds of bilayers. Selectivity coefficients KK+, Na+, KK+, Li+, KK+, Ca2+ and KK+, Mg2+ are 10(-4), 10(-4), 2 x 10(-5) and 3 x 10(-5) respectively, and there is no obvious difference among different fabricating methods. A linear response toward the potassium ion was found in the range from 10(-1) M to 10(-5) M with the detection limit of 10(-6) M. The sensor has a slope of 60 mV per decade. Meanwhile, the longevity of the sensor was improved obviously for at least two months at about -10 degrees C. The higher stability shows the possibility to fabricate a practical biosensor.