Papers by Keyword: Radical

Abstract: The paper studies the processes occurring in low-temperature plasma in the magnetic field. It shows that the laser excitation of molecular oxygen can increase the fraction of singlet pairs formed as a result of collisions between oxygen and carbon molecules. This facilitates the separation of ¹²С and ¹³С isotopes.

Abstract: In present study, in vitro antioxidant activities of polysaccharide from Agaricus bisporus mycelia (PABM) were evaluated using 1,1-diphenyl-2-picrylhydrazy (DPPH), hydroxyl (ˑOH) and superoxide anion (ˑO₂^-) radicals scavenging activities. The results indicated that PABM could significantly scavenge DPPH, hydroxyl and superoxide anion radicals. Thus, PABM can be used as natural antioxidants in functional foods or medicine.

Abstract: In this article, UV effect onto polysiloxane-modified-polyacrylates and asphalt were researched. For polysiloxane-modified-polyacrylates, it was found that the by adding photosensitive monomers UV can enhance the cross link between molecules, and there is an optimum ratio. For the asphalts, UV will make the materials ageing, because it will break the large molecules into smaller ones. And addition of anti-UV ageing agents may but not necessarily help the anti-ageing process. There is a specific corresponding relationship between them.

Abstract: It is known that chemical bonding is only possible when particles with antiparallel valence electrons spins orientation collide [1, 2]. In an external magnetic field unpaired electrons spins precession around the field lines is observed. Precession frequencies of valence electrons of magnetic and nonmagnetic nuclei differ, resulting in a different probability to collide in reactive state for different isotopes. The investigations results of magnetic field influence on the carbon isotopes redistribution between carbon dioxide and disperse carbon in plasmachemical processes are given. Argon-oxygen plasma by a high-frequency generator was produced. Carbon placed into reaction zone by the high-frequency electrode evaporation. The plasmachemical reaction products quenching in the plasma flow at the sampler probe were examined. It is found that the Laval nozzle sampler is more efficient for plasma stream cooling versus the cylindrical sampler. The effects of flow rate, pressure and carbon dioxide concentration on the plasma flow cooling efficiency were estimated.

Abstract: The aim of this study was to observe the antioxidant effect of hydrolysates derived from bighead carp protein (HBCP). The effect was observed through the life span experiment of D. melanogaster and was evaluated by antioxidant indexes of D-galactose (D-gal) induced senile mice. The mean and maximum life span of D. melanogaster with HBCP supplement in nutritional medium was compared to that of control group, which were fed without any addition. The senile mice were induced by celiac injection of D-gal for six week. Experiment groups received HBCP at different dosages (3 g/kg, 1.5 g/kg and 0.5 g/kg) by intragastric administration, while the aged group received saline every day. Contents of malonadehide (MDA), activities of superoxide dimutase (SOD) and glutathione peroxidase (GSH-Px) were determined. The results showed that the addition of HBCP in feedstuff could increase the mean and maximum life span of D. melanogaster. Compared to the D-gal induced senile group, contents of liver and brain MDA in mice which received HBCP (3 g/kg and 1.5 g/kg) by intragastric administration were significantly decreased (p<0.01), while the activities of the antioxidative enzyme were increased. This result indicated that HBCP had an antioxidant effect for D-gal induced senile mice and can extend the life span of D. melanogaster.

Abstract: This study investigates the growth mechanisms of carbon nanowalls (CNWs), which are two-dimensional carbon structures that consist of stacked graphene sheets and that stand vertically on substrates. Factors that determine their morphological and electrical properties were studied using two plasma-enhanced chemical vapor deposition (PECVD) systems that permit the densities and energies of radicals and ions to be precisely controlled. For CNW growth using a C2F6/H2 plasma, the CNW growth rate decreased when the total pressure was increased from 13.3 to 80 Pa during growth. Raman spectroscopy and scanning electron microscopy revealed that the CNW crystallinity increases and the CNW density decreases with increasing total pressure. This is attributed to an increasing amount of H radicals in the growth ambient with increasing total pressure. During the initial stages of CNW growth using a multibeam PECVD system with CFx, hydrogen radicals, and Ar ions, CNWs were formed only for Ar+-ion fluxes of 3.3 to 3.8 A/cm2 and energies of 200 to 250 eV. Although attachment of CFx radicals and CNW growth require ion bombardment, if the flux or energy of ion bombardment is too high CNW growth will be inhibited due to etching and excessive carbon deposition. Semiconducting CNWs with n-type characteristics can be formed by adding N2 gas to the C2F6/H2 plasma. Furthermore, carrier concentrations of n-type CNWs can be controlled by nitrogen doping.

Abstract: In this study, effects of ultrasound processing time, ultrasound power and solid liquid ratio of ultrasonic on pumpkin polysaccharide extraction were investigated. The optimum parameters of extracting pumpkin polysaccharides are obtained by orthogonal test. Antioxidant activity were evaluated by using various established invitro systems, including 1,1-diphenyl-2-picrylhydrazylthe(DPPH•), hydroxyl(•OH) and FRAP system. Results showed that the extraction rate of polysaccharides pumpkin could up to 12.37% which the condition were water as extractant, ultrasonic time is 10min, ultrasonic power is 400w, solid to liquid ratio is 1:20. The polysaccharide raised the total antioxidant capacity in a dose-dependent manner. The results suggested that polysaccharide had direct and potent antioxidant activities.

Abstract: This work deals with the application of ozonated water for the BEOL stripping of DUV-resists. For this purpose analytical techniques for the quantification of molecular O3 in the water as well as methods for the non-destructive analysis of resists on wafers have been studied. The aim is to be able to determine the concentrations of O3, its decomposition, under the influence of various parameters, and to correlate these data with the polymer structure of the resist on the wafer and the efficiency of resist removal.