Low-Energy Electron Scattering from c-C4F8

Electron collision cross-sections of c-C4F8 were investigated at low energies by using the R-matrix method. The static exchange (SE), static exchange with polarization (SEP), and close-coupling (CC) models of the R-matrix method were used for the calculation of the scattering cross-section. The shape resonance was detected with all the models at around 3~4 eV, and a Feshbach resonance was detected with the SEP model at 7.73 eV, in good agreement with the previous theoretical calculation. The resonance detected was also associated with the experimental dissociative electron attachment of c-C4F8, which displayed the resonances at the same energy range. The cross-sections calculated are important for plasma modeling and applications

Evolution of electron temperature in inductively coupled plasma

It is generally recognized that the electron temperature T_e either remains constant or decreases slightly with plasma power (plasma density). This trend can be simply verified using a single-step or multi-step fluid global model. In this work, however, we experimentally observed that T_e evolved with plasma power in radio frequency (RF) inductively coupled plasmas. In this experiment, the measured electron energy distributions were nearly Maxwellian distribution. In the low RF power regime, T_e decreased with increasing plasma power, while it increased with plasma power in the high RF power regime. This evolution of T_e could be understood by considering the coupling effect between neutral gas heating and stepwise ionization. Measurement of gas temperature via laser Rayleigh scattering and calculation of T_e using the kinetic model, considering both multi-step ionization and gas heating, were in good agreement with the measured value of T_e. This result shows that T_e is in a stronger dependence on the plasma power

In Vitro and In Vivo Studies on Quercus acuta

Quercus acuta Thunb. (Fagaceae) (QA) is cultivated as a dietary and ornamental plant in China, Japan, South Korea, and Taiwan. It has been widely used as the main ingredient of acorn tofu, a traditional food in China and South Korea. The aim of this study was to determine in vitro and in vivo xanthine oxidase (XO) inhibitory and antihyperuricemic activities of an ethyl acetate extract of QA leaf (QALE) and identify its active phytochemicals using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography (LC) systems. The QALE was found to possess potent in vitro antioxidant and XO inhibitory activities. In vivo study using hyperuricemic mice induced with potassium oxonate demonstrated that the QALE could inhibit hepatic XO activity at a relatively low oral dose (50 mg/kg) and significantly alleviate hyperuricemia to a similar extent as allopurinol. Several active compounds including vitamin E known to possess XO inhibitory activity were identified from the QALE. To the best of our knowledge, this is the first study that reports the active constituents and antihyperuricemic effect of QA, suggesting that it is feasible to use QALE as a food therapy or alternative medicine for alleviating hyperuricemia and gout

Temporal and Spatial Distribution of Sulfur Dioxide in Ulsan, Korea

We investigated the temporal and spatial distribution of SO2 measured at 14 air pollution monitoring sites in Ulsan, Korea. The levels of SO2 in Ulsan have continuously decreased since the 1990s, and a recent (2005-2009) annual average concentration of 8 ppb is lower than the national guideline of 20 ppb. However, Ulsan has higher levels of SO2 than any other mega-city in Korea. The average level of SO2 at industrial sites (13.7ppb) is 2.4 times higher than those at residential and commercial sites. According to the measurement data, meteorological condition, and former air dispersion modeling results, it was confirmed that SO2 emitted from the industrial complex was transported to the residential area by sea-land breeze and southeastern seasonal winds. For the improved air quality in Ulsan, the current environmental policy permitting the use of high-sulfur oil (<4%) should be carefully evaluated. The emission of greenhouse gases and hazardous air pollutants (HAPs) as well as SO2 from plants using the high-sulfur oil should be monitored. Furthermore, separated environmental policies for the industrial and residential areas are required for more effective pollution management.clos