GROWTH OF GRAPHENE FILMS AND GRAPHENE PATTERNS

Large area graphene can be fabricated by depositing carbon and catalytic metal thin film(s) on a substrate, heating the carbon and the catalytic metal, and forming graphene on the substrate. The catalytic metal is evaporated during the heating process. The catalytic metal can be, for example, nickel, cobalt, or iron

'Yellow Peril': Contradictions of Race in James Ellroy's Perfidia

James Ellroy’s treatment of race continues to captivate and polarize both popular and academic opinion. Whilst some see the casual racism and often uncomfortable stereotypes in Ellroy’s work as a reflection of the author’s own political agenda, for others Ellroy’s work offers a complex deconstruction of both racial identity and white social power. Focusing on his novel Perfidia, this paper explores these contradictions and paradoxes in Ellroy’s representations of race, arguing that whilst the novel depicts and forcefully overemphasizes an historical moment fraught with a brand of physiognomic racism that persecutes individuals on the basis of biological difference, it simultaneously deconstructs such essentialist engenderings by foregrounding the performative dimensions of race as a category of identity. As a result, this paper argues that Ellroy’s novel “visibilizes” the socially and institutionally constructed nature of race, deconstructing and destabilizing the integrity and authority of white social power. Yet, this paper also suggests that through such an unyielding portrayal of white power, Perfidia only partly dislodges the authority and power of institutional whiteness, and can in fact be seen to validate the sustainment of such apparatus

GROWTH OF GRAPHENE FILMS AND GRAPHENE PATTERNS

Large area graphene can be fabricated by depositing carbon and catalytic metal thin film(s) on a substrate, heating the carbon and the catalytic metal, and forming graphene on the substrate. The catalytic metal is evaporated during the heating process. The catalytic metal can be, for example, nickel, cobalt, or iron

GROWTH OF NITRIDE FILMS

A gallium nitride thin film can be formed on a substrate at a low temperature (e.g., not higher than 600°C .) by applying a laser to resonantly excite molecules of a first precursor that contains nitrogen, in which the laser has a wavelength that is selected to match a vibration mode and/or a vibrational rotational mode of the molecules of the first precursor. A second precursor is provided in which the excited first precursor and the second precursor react to form a nitride that is deposited on the substrate. For example, the second precursor may include gallium, and the nitride may be gallium nitride. Other nitride films can be produced in a similar manner

Pharmacological Basis for Use of Armillaria mellea

Armillaria mellea, an edible fungus, exhibits various pharmacological activities, including antioxidant and antiapoptotic properties. However, the effects of A. mellea on Alzheimer’s disease (AD) have not been systemically reported. The present study aimed to explore the protective effects of mycelium polysaccharides (AMPS) obtained from A. mellea, especially AMPSc via 70% ethanol precipitation in a L-glutamic acid- (L-Glu-) induced HT22 cell apoptosis model and an AlCl3 plus D-galactose- (D-gal-) induced AD mouse model. AMPSc significantly enhanced cell viability, suppressed nuclear apoptosis, inhibited intracellular reactive oxygen species accumulation, prevented caspase-3 activation, and restored mitochondrial membrane potential (MMP). In AD mice, AMPSc enhanced horizontal movements in an autonomic activity test, improved endurance times in a rotarod test, and decreased escape latency time in a water maze test. Furthermore, AMPSc reduced the apoptosis rate, amyloid beta (Aβ) deposition, oxidative damage, and p-Tau aggregations in the AD mouse hippocampus. The central cholinergic system functions in AD mice improved after a 4-week course of AMPSc administration, as indicated by enhanced acetylcholine (Ach) and choline acetyltransferase (ChAT) concentrations, and reduced acetylcholine esterase (AchE) levels in serum and hypothalamus. Our findings provide experimental evidence suggesting A. mellea as a neuroprotective candidate for treating or preventing neurodegenerative diseases

Lamellar thickness and stretching temperature dependency of cavitation in semicrystalline polymers

Polybutene-1 (PB-1), a typical semicrystalline polymer, in its stable form I shows a peculiar temperature dependent strain-whitening behavior when being stretched at different temperatures where the extent of strain-whitening weakens with the increasing of stretching temperature reaching a minima value followed by an increase at higher stretching temperatures. Correspondingly, a stronger strain-hardening phenomenon was observed at higher stretching temperatures. The strain-whitening phenomenon in semicrystalline polymers has its origin of cavitation process during stretching. In this work, the effect of crystalline lamellar thickness and stretching temperature on the cavitation process in PB-1 has been investigated by means of combined synchrotron ultrasmall-angle and wide-angle X-ray scattering techniques. It was found that, with respect to the cavitation process, three modes of cavitation during the stretching process can be identified, namely no cavitation for sample with the thinnest lamellae where only shear yielding occurred, cavitation with reorientation for the samples stretched at lower temperatures and samples with thicker lamellae, and cavitation without reorientation for samples with thinner lamellae stretched at higher temperatures. The mode cavitation with reorientation occurs before yield point where the plate-like cavities start to be generated within the lamellar stacks with normal perpendicular to the stretching direction due to the blocky substructure of the crystalline lamellae and reorient gradually to the stretching direction after strain-hardening. The mode of cavitation without reorientation appears after yield point where ellipsoidal shaped cavities are generated in those lamellae stacks with normal parallel to the stretching direction followed by an improvement of their orientation at larger strains.Comment: 14 pages, 13 figure

Temperature variations at the Great Wall and Zhongshan stations

Surface meteorological observations have been carried out at the Great Wall station (GW) and Zhongshan station (ZS) from 1984 to 2008 and from 1989 to 2008 respectively. The variation in mean air temperature and its trends are derived from the meteorological observation data recorded at both stations. The warming rate of the annual mean temperature at GW is similar to that at Bellingshausen station, which is about 3 km distant. Thus, the warming trend is representative of the King George Island region. The warming rate of ZS is less different from that at Davis station, which is about 100 km from ZS. It can be said that the meteorological data recorded at both stations are representative of the regions of the King George Island and east coast of the Antarctic

Femtosecond Photon-Mediated Plasma Enhances Photosynthesis of Plasmonic Nanostructures and Their SERS Applications

Laser ablation in liquid has proven to be a universal and green method to synthesize nanocrystals and fabricate functional nanostructures. This study demonstrates the superiority of femtosecond laser-mediated plasma in enhancing photoredox of metal cations for controllable fabrication of plasmonic nanostructures in liquid. Through employing upstream high energetic plasma during laser-induced microexplosions, single/three-electron photoreduction of metallic cations can readily occur without chemical reductants or capping agents. Experimental evidences demonstrate that this process exhibits higher photon utilization efficiency in yield of colloidal metal nanoparticles than direct irradiation of metallic precursors. Photogenerated hydrated electrons derived from strong ionization of silicon and water are responsible for this enhanced consequences. Furthermore, these metallic nanoparticles are accessible to self-assemble into nanoplates for silver and nanospheres for gold, favored by surface-tension gradients between laser irradiated and unirradiated regions. These metallic nanostructures exhibit excellent surface-enhanced Raman spectroscopy performance in trace detection of Rhodamine 6G (R6G), 4-mercaptobenzoic acid (4-MBA), and mercapto-5-nitrobenzimidazole molecules with high sensitivity (down to 10–12 mol L–1, 30 × 10–15 m for R6G), good reproducibility (relative standard deviation \u3c 7%), and good dual-analyte detection ability with mixture ratios of R6G to 4-MBA ranging from 20 to 0.025. The conceptual importance of this plasma-enhanced-photochemical process may provide exciting opportunities in photochemical reactions, plasmofluidics, and material synthesis. Includes Supplementary Material

Direct observation of structure-assisted filament splitting during ultrafast multiplepulse laser ablation

Laser-induced plasma evolution in fused silica through multipulse laser ablation was studied using pump-probe technology. Filament splitting was observed in the early stage of plasma evolution (before ~300 fs). This phenomenon can be attributed to competition between laser divergent propagation induced by a pre-pulse-induced crater and the nonlinear self-focusing effect. This effect was validated through simulation results. With the increasing pulse number, the appearance of filament peak electron density was postponed. Furthermore, a second peak in the filament and peak position separation were observed because of an optical path difference between the lasers propagating from the crater center and edge. The experimental results revealed the influence of a prepulse-induced structure on the energy distribution of subsequent pulses, which are essential for understanding the mechanism of laser–material interactions, particularly in ultrafast multiple-pulse laser ablation