Facile one-step route to polyaniline–silver nanocomposite particles and their application as a colored particulate emulsifier

Polyaniline–silver nanocomposites were synthesized in the form of colloidal particles by the facile one-step aqueous chemical oxidative dispersion polymerization of aniline using silver nitrate as an oxidant and poly(vinyl alcohol) as a colloidal stabilizer. Aniline monomer was oxidized by silver ions, yielding polyaniline and elemental Ag simultaneously. The synthesized nanocomposite particles were colloidally stable over 2 years and transmission electron microscopy studies indicated the production of spherical, plate and rod-shaped polyaniline–silver nanocomposite particles with a silver core–polyaniline shell morphology. The conductivity of a pressed pellet of the nanocomposite particles using the conventional four-point probe technique was 1.4 × 10^?2 S/cm at 25 °C. The nanocomposite particles behaved as a ‘colored’ particulate emulsifier for the stabilization of transparent oil-in-water emulsions.     

The effect of write current on thermal flying height control sliders with dual heater/insulator elements

The effect of write induced pole tip protrusion on the magnetic spacing of the head/disk interface has to be taken into consideration as flying heights approach the spacing regime of a few nano-meters. Thermal flying height control (TFC) sliders are presently in common use in hard disk drives to control the flying height at the read/write element during drive operations. In this paper the flying characteristics of TFC sliders with dual heater/insulator elements are investigated. Simulation results are shown for situations where the write current is ??on?? and where the write current is ??off??. The effect of design parameters of two heater/insulator elements is studied to optimize the performance of TFC slider.     

Drivability improvement on deep-submicron MOSFETs by elevation ofsource/drain regions

Deep submicron MOSFETs with elevated source/drain (S/D) structures, where S/D extension regions were partially elevated besides deep S/D regions, were fabricated by use of Si selective epitaxial growth technique. As fairly compared with a well-developed conventional MOSFET, we clarify an advantage of the elevated S/D structures, i.e., improvement upon driving performance with keeping excellent short-channel characteristics, which is enhanced for decrease in gate sidewall spacer width. The experimental results are explained in terms of the reduction in S/D parasitic resistance by addition of the Si epitaxial layer where the impurity profile is suitable     

Theoretical development of the method of caustics for intersonically propagating interfacial crack

In this paper, a theory of caustics for an intersonically propagating interfacial crack is developed. Using the first invariant of stress singular field in the vicinity of the intersonically propagating tip of an interface crack, mapping equations are derived for the caustic curve on the reference plane as well as the initial curve on the specimen plane. The effect of the crack velocity on the caustic pattern is investigated. Two practically measurable characteristic dimensions are proposed. Using these characteristic dimensions, a simple procedure is also proposed for the evaluation of the stress singularity factor for the intersonically propagating interfacial crack.     

A variational principle for minimizing experimental measurement errors and its application to a hybrid experimental-numerical method

In general, experimentally measured fields such as moiré-interferometry fringes contain various errors associated with the measurement and subsequent data analysis. Moreover, the measured displacement field does not necessarily satisfy the equilibrium equation in solid mechanics, especially when the measurement errors are involved. First, a variational principle minimizing the experimental measurement errors is derived to overcome such difficulties. Next, on the basis of this variational principle, a new hybrid moiré-interferometry and finite-element method is developed. Concepts of restoration energy and restoration force are also presented in the context of the present hybrid method. The present hybrid method demonstrates automatic detection and elimination of the measurement errors and smooth visualization of stress contours. The present hybrid method automatically achieves the path independence of the J integral, restoring the path-dependence caused by the measurement errors.     

Analysis of damaged material containing periodically distributed elliptical microcracks by using the homogenization method based on the superposition method

The presence of multiple microcracks in a structural component causes material degradation such as reduction in the stiffness or reduction in the fracture toughness of the component. In this paper, the homogenization method is used to evaluate mechanical properties of the damaged material. The adaptation of the superposition method to the homogenization method is also presented. The proposed method makes use of the finite element solution of uncracked solid and the analytical solution. The effective elastic moduli of damaged materials containing lattice-distribution microcracks are estimated by the proposed method. Furthermore, the stress fields and the stress intensity factors of the elliptical microcracks in the damaged material at a micro-mechanics scale are evaluated to illustrate microscopic behavior such as crack interaction.     

EFFECTS OF HEXASULFOBUTYLATED C60 ON THE GASTRIC CIRCULAR MUSCLE OF GUINEA PIG

The effects of hexasulfobutylated (FC₄S), the fullerene derivative on the contraction of smooth muscle were tested pharmacologically on the circular muscle of stomach of guinea pigs. The effects of monomalonic acid C₆₀ (MMA C₆₀) on the same preparations were compared. The effects of those compounds on the taenia coli, portal vein and vas deferens of guinea pigs were also tested. The FC₄S did, while MMA C₆₀ did not elicit contracture of the circular muscle of stomach and taenia coli. Both FC₄S and MMA C₆₀ did not elicit contraction on the portal vein and on the vas deferens of the guinea pig. Prazosin (0.5 μM) or propranolol (0.5 μM) did not alter the FC₄S elicit contracture of the circular muscle of stomach. However, atropine (0.01, 0.1 and 1 μM), tetrodotoxin (0.1 μM) or low calcium medium decreased reversibly the FC₄S elicited contracture of the circular muscle of stomach. The effect of FC₄S on the contracture of the gastric muscles was also tested using various muscarinic receptor subtype antagonists. 4-DAMP (1 μM), muscarinic M3 receptor antagonist, and tropicamide (1 μM), muscarinic M4 receptor antagonist, did not alter the contracture elicited by FC₄S. Pirenzepine (0.1 μM), muscarinic M1 receptor antagonist, and methoctramine (0.25 μM), muscarinic M2 receptor antagonist, significantly decreased the FC₄S elicited contracture of the circular muscle. Atropine (1 μM) or tetrodotoxin (0.1 μM) completely blocked the FC₄S elicited contracture of the circular muscle of stomach. It is concluded that FC₄S elicited contracture of the circular muscle of stomach. The effect may be due to FC₄S acts on the cholinergic cells existed in the gastric muscle and indirectly activating the tetrodotoxin dependent releasing of the transmitters from the cells, then, activating the muscarinice M1, M2 receptors in the muscle eliciting the contractures.     

Single molecule fluorescence autocorrelation measurement on anisotropic molecular diffusion in nematic liquid crystal

Diffusion kinetics of three dyes in nematic liquid crystals are studied with single-molecule fluorescence autocorrelation spectroscopy. Markedly large anisotropy was observed in the diffusion coefficient and structure of diffusion molecules showed no marked effect on the anisotropy.     

New bleeding model of additives in a polypropylene film under atmospheric pressure II

Many additives are commercially used to add more favorable qualities to films. The bleeding process by which the additive in a film comes to the surface is considered. A new bleeding model of additives in a polypropylene film under atmospheric pressure was investigated. Solubility and diffusion are found to be important for explaining this bleeding process. It was found that the experimental results were explained more precisely by assuming a two‐step transport process between the crystalline regions and the amorphous ones. The solubilities and diffusion coefficients of UV‐stabilizers such as 2‐(2H‐benzotriazol‐2‐yl)‐4‐(1,1,3,3‐tetramethylbutyl)phenol and 2‐(2H‐benzotriazol‐2‐yl)‐4‐methylphenol were determined at 40°C. The difference between the saturation solubilities and the diffusion coefficients of UV‐stabilizers was discussed by comparing with the results of molecular dynamics (MD) simulation. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis of TiN and TiC powders by a reduction/nitridation method using arc image heating

Journal of Materials Science Letters -