Sol-gel ZnO-SiO/sub 2/ composite waveguide ultraviolet lasers

Random laser action with coherent feedback is realized in ZnO-SiO/sub 2/ composite films, which consists of ZnO clusters embedded in SiO/sub 2/ dielectric matrix prepared by sol-gel technique. The films are deposited on silicon substrate with a SiO/sub 2/ buffer layer to form a waveguide structure. Ultraviolet lasing at room temperature is observed from the composite films with ZnO : SiO/sub 2/ molar ratio varying between 1 : 5 and 1 : 30. The corresponding lasing wavelength and linewidth under 355-nm optical excitation are found to be /spl sim/388 nm and less than 0.6 nm, respectively. Our experiment has shown that the proper control of light confinement inside the random cavities leads to coherent random lasing.     

Series Representations for Rice's Ie Function

Two new series representations for the Rice functionIe (k, x)are presented. One of the series involves the modified Struve functions and the other involves the modified Bessel functions. These two series complement each other in their convergence speeds as functions of the values ofkandx. The truncation error bounds are derived for both series. Therefore, they can be used alternatively with high efficiency and known precision.     

Graphite intercalation chemistry: An interpretive review

It was but five years ago that Forsman, and Ebert and Selig suggested independently that redox chemistry might be intrinsic to the formation of so-called acceptor compounds. Since then, much of the work in chemical aspects of intercalation has been specifically directed at verifying or disproving this hypothesis. The wealth of new data compiled in the process, coupled with a meticulous review of past evidence, confirms the essential role of oxidation in this genre of intercalation reactions.This review addresses two particular issues in the chemistry of acceptor type intercalants. First, how the oxidative or coordinating capability of a chemical species relates to its behavior as an intercalant. There has been considerable emphasis on the broad spectrum of interactions which exist, from weak charge transfer (Br₂ compounds), to oxidative intercalation (e.g., HNO₃), to reactions so vigorous that intercalation is only achieved with accompanying fluorination of the lattice and partial destruction of the sp² character of the carbon network (certain inorganic fluoride systems). Ebert and Selig have pointed out that detrimental oxidations of this sort are always an alternate reaction pathway in oxidative intercalation; the particular intercalant and reaction conditions determine which products will dominate. Secondly, what is the mechanism by which the intercalant interacts with the π-electron system and what are the reactive intermediates? In contrast to the previous topic—which relies on concrete evidence such as final product composition and properties for its resolution—here the approach has been largely hypothetical, relying on analogy to inorganic coordination compounds and organic π-systems which participate in charge transfer reactions. Here also lies, perhaps, the greatest future challenge to the intercalation chemist. For while the devising of possible reaction mechanisms is accomplished easily enough, experimental confirmation is always difficult. However, the past record of cooperation between chemist and physicist, experimenter and theoretician in intercalation science is an impressive one. If this question of mechanism is approached with the same gusto that has characterized past efforts, we should have some answers before long.     

Film insert molding as a novel weld‐line inhibition and strengthening technique

Specimens with weld lines were produced via conventional and film insert molding techniques using two types of materials as the substrate resin, i.e. a polycarbonate/acrylonitrile‐butadiene‐styrene (PC/ABS) blend and glass fiber‐filled polycarbonate (PC‐gf). The formation and morphology of the weld line region was assessed with and without the presence of 0.5‐mm‐thick PC film inserts. The weld line formation and characteristics were found to be dependent on the extent of interaction between the injected resin and the mold surface or the film insert. Better interfacial interaction between the substrate and film led to the distortion of the weld line orientation, which significantly enhanced the mechanical properties of the weld line. The incorporation of glass fibers into the substrate resin would usually reduce the resistance of the weld line towards tensile, flexural and impact loadings. However, with the attachment of film inserts, the mechanical properties of the weld line region have significantly improved, even with the presence of rigid fibers. Upon examination of tensile and impact fracture surfaces of film insert specimens, a unique orientation of fibers across the weld line (parallel to the flow direction and perpendicular to the weld line) could be observed at regions directly under the film. The combination of favorable properties from the unique fiber orientation and distortion of the weld line, as well as the ability of the film to effectively dissipate forces towards a larger area, have synergistically contributed towards the mechanical property enhancement of the weld line region in film insert moldings. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Dangerous misidentification of people due to flashback phenomena in posttraumatic stress disorder

Changes in the fatty acid composition of phospholipid and triglyceride fractions in Spirometra erinaceieuropaei plerocercoids were investigated after 0, 0.5, 1, 3, and 6 hr incubation at 10 C and 37 C with physiological saline containing 5 mM arachidonic acid and 10 mg/ml bovine serum albumin, pH 7.0. At 37 C, arachidonic acid was absorbed and incorporated rapidly into the triglyceride fraction (over 14.4% in composition), and decreased after 2-3 hr; at 10 C, the amount of triglyceride increased slowly and continued to a maximum of 12.9% during 6 hr of incubation. We used a simplified method to extract and purify prostaglandins from the plerocercoid of S. erinaceieuropaei. Prostaglandins were quantified using gas chromatography-mass spectrometry. Prostaglandin E2, PGD2, PGF2alpha, and 6-keto-PGF1alpha were detected under different incubation conditions. In the dose-dependent experiment, PGD2 was detected in plerocercoids incubated with 0.5, 1, 2, and 5 mM arachidonic acid, pH 7.0, at 25 C; PGE2 was detected with 2 and 5 mM arachidonic acid. In the time-dependent experiment, where plerocercoids were incubated with 5 mM arachidonic acid, pH 7.0 at 25 C, PGF2alpha was first detected at 15 min; thereafter, 6-keto-PGF1alpha was detected at 30 min and PGD2 and PGE2 were detected at 1 hr. Thromboxane B2 was not detected in either the dose-dependent or time-dependent experiments, and only PGE2 was detected in the incubation medium with 5 mM arachidonic acid at 1 hr. These results reveal that when plerocercoids change from reptilian to mammalian hosts, they are able to absorb and modify arachidonic acid bound to albumin and generate prostaglandins under suitable conditions. Prostaglandins exhibit potent biological functions for immunoresponses that may be relevant to parasitism and the success of larva migrans in S. erinaceieuropaei.     

The production of pork with garlic flavour notes using garlic essential oil

Garlic essential oil (GEO) added directly to pork mince or to the diet of pigs was evaluated for its effectiveness in masking undesirable mutton flavour. Pork was from 31 female pigs (Duroc × (Large White × Landrace)) grown on diets containing either animal-plus-plant products (AP diet) or plant products only (P diet) with four levels of GEO: 0, 0.55, 1.44 and 1.84 g/kg feed and 0, 0.55, 1.44 and 2.15 g/kg feed in the AP and P diet, respectively. Garlic flavour increased and mutton flavour decreased in pork from pigs that consumed more than about 150 g and 220 g of GEO in P and AP diets, respectively over the 57-day feeding period. The garlic flavour was stronger and the mutton flavour less intense for pork from pigs on the P diet. When GEO was added to pork mince at 125 ppm, it significantly reduced mutton flavour.