Effect of argon ion bombardment on amorphous silicon carbonitride films

Amorphous silicon carbonitride (a-SiCN:H) films were synthesized by radiofrequency (RF) Plasma Enhanced Vapor Chemical Deposition (PECVD) using hexamethyldisilazane (HMDSN) as precursor compound. Then, the films were post-treated by Plasma Immersion Ion Implantation (PIII) in argon atmosphere from 15 to 60 min The hardness of the film enhanced after ion implantation, and the sample treated at 45 min process showed hardness greater than sixfold that of the untreated sample. This result is explained by the crosslinking and densification of the structure Films were exposed to oxygen plasma for determining of the etching rate. It decreased monotonically from 33 angstrom/min to 19 angstrom/min for the range of process time, confirming structural alterations. Hydrophobic character of the a-SiCN:H films were modified immediately after ion bombardment, due to incorporation of polar groups. However, the high wettability of the films acquired by the ion implantation was diminished after aging in air. Therefore, argon PIII made a-SiCN.H films mechanically more resistant and altered their hydrophobic character.

Type of Intercept Trap Not Important for Capturing Female Sirex noctilio and S-nigricornis (Hymenoptera: Siricidae) in North America

Current detection tools for Sirex noctilio F. (Hymenoptera: Siricidae) in North America are poor. To determine the importance of intercept trap type for capturing females of S. noctilio and its native congener, Sirex nigricornis F., in eastern North America, we report on seven trap comparison studies from different years and geographic locations. Among studies, total numbers of S. noctilio captured were low (mean of <= 1waspper trap). Total numbers of S. nigricornis caught were generally greater, andranged from ameanof 1-13 wasps per trap. Nearly all studies found no significant differencesamongintercept trap types in the number of woodwasps caught. For future studies, we recommend that either panel or 12-unit Lindgren funnel traps be used to catch S. noctilio or S. nigricornis in eastern North America.

Effect of resin composites with sodium trimetaphosphate with or without fluoride on hardness, ion release and enamel demineralization

Purpose: To evaluate the effect of the addition of sodium trimetaphosphate (TMP) with or without fluoride on enamel demineralization, and the hardness and release of fluoride and TMP of resin composites. Methods: Bovine enamel slabs (4x3x3 mm) were prepared and selected based on initial surface hardness (n= 96). Eight experimental resin composites were formulated, according to the combination of TMP and sodium fluoride (NaF): TMP/NaF-free (control), 1.6% sodium fluoride (NaF), and 1.5%, 14.1% and 36.8% TMP with and without 1.6% NaF. Resin composite specimens (n= 24) were attached to the enamel slabs with wax and the sets were subjected to pH cycling. Next, surface and cross-sectional hardness and fluoride content of enamel as well as fluoride and TNT release and hardness of the materials were evaluated. Data were statistically analyzed using ANOVA (P< 0.05). Results: The presence of fluoride in enamel was similar in fluoridated resin composites (P> 0.05), but higher than in the other materials (P< 0.05). The combination of 14.1% TMP and fluoride resulted in less demineralization, especially on lesion surface (P< 0.05). The presence of TMP increased fluoride release from the materials and reduced their hardness.

Silver ion release from electrodes of nanotubes of TiO2 impregnated with Ag nanoparticles applied in photoelectrocatalytic disinfection

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Study of magnetic field enhanced plasma immersion ion implantation in Silicon

A comparison between experimental measurements and numerical calculations of the ion current distribution in plasma immersion ion implantation (PIII) with external magnetic field is presented. Later, Silicon samples were implanted with nitrogen ion to analyze the effect on them. The magnetic field considered is essentially non-uniform and is generated by two magnetic coils installed on vacuum chamber. The presence of both, electric and magnetic field in PIII create a crossed ExB field system, promoting drift velocity of the plasma around the target. The results found shows that magnetized electrons drifting in ExB field provide electron-neutral collision. The efficient ionization increases the plasma density around the target where a magnetic confinement is formed. As result, the ion current density increases, promoting significant changes in the samples surface properties, especially in the surface wettability.

Microwave-assisted hydrothermal synthesis of magnetite nanoparticles with potential use as anode in lithium ion batteries

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electrochemical Properties of the Oxo-Manganese-Phenanthroline Complex Immobilized on Ion-Exchange Polymeric Film and Its Application as Biomimetic Sensor for Sulfite Ions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gas sensor applications of zinc oxide thin film grown by the polymeric precursor method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electrical conductivity of Ag-Na ion exchanged soda-lime glass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Amorphous silicon carbonitride films modified by plasma immersion ion implantation

Amorphous silicon carbonitride (a-SiCN:H) films were deposited from hexamethyldisilazane (HMDSN) organic compounds via radio-frequency (RF) glow discharges. Afterwards the films were bombarded, from 15 to 60 min, with nitrogen ions using Plasma Immersion Ion Implantation (PIII) technique. X-ray photoelectron spectroscopy (XPS) showed that O-containing groups increased, while C-C and/or C-H groups decreased with treatment time. This result indicates chemical alterations of the polymeric films with the introduction of polar groups on the surface, which changes the surface wettability. In fact, the hydrophobic nature of a-SiCN:H films (contact angle of 100 degrees) was changed by nitrogen ion implantation and, and after aging in atmosphere air, all samples preserved the hydrophilic character (contact angle <80 degrees) independently of treatment time. The exposure of the films to oxygen plasma was performed to evaluate the etching rate, which dropped from 24% to 6% while the implantation time increased from 15 to 60 min. This data suggests that Pill increased the film structure strength, probably due to crosslinking enhancement of polymeric chains. Therefore, the treatment with nitrogen ions via Pill process was effective to modify the wettability and oxidation resistance of a-SiCN:H films. (C) 2014 Elsevier Ltd. All rights reserved.

Daily photosynthesis, water relations, and ion concentrations of uuonymus irrigated with treated wastewater

Euonymus japonica Thunb. (euonymus) plants were submitted for 9 months to two irrigation treatments using water from different sources: a control (C) water with electrical conductivity (EC) less than 1.2 dS.m(-1) and reclaimed wastewater (RW) with EC approximate to 4 dS.m(-1). At the end of the experiment, no differences in the total dry weight were observed between treatments, whereas the leaf dry mass increased (to the detriment of the root part in RW plants). Throughout the day, the stem water potential (Psi(stem)) of the RW plants was lower than in C, whereas stomatal conductance (g(S)) was slightly reduced in RW from 0800 HR to 1200 HR, but no significant variation in photosynthesis (P-n) or energy conversion efficiency (F'(v)/F'(m)) in photosystem II was detected through the effect of salinity. Gas exchange and fluorescence showed a tendency to increase after midday in plants treated with RW. The photosynthetic behavior and fluorescence of RW plants may have been related to the nitrogen and chlorophyll content of the leaves, confirming the resistance of the photosynthetic mechanism to salinity in this species in these conditions. The toxic effects produced by high concentrations of boron (B), sodium (Na+) and chloride (Cl-) were offset by the effect of other ions like magnesium (Mg2+), potassium (K+), and phosphorus (P) in plants irrigated with RW, thus improving their physiological status without decreasing their ornamental value.

Hydrogen ion and calcium releasing of MTA Fillapex® and MTA-based formulations

MTA is composed of various metal oxides, calcium oxide and bismuth. It has good biological properties and is indicated in cases of endodontic complications. Several commercial formulations are available and further studies are necessary to evaluate these materials. Objective: To evaluate pH and calcium releasing of MTA Fillapex® compared with gray and white MTA. Material and methods: Gray and white MTA (Angelus) and MTA Fillapex® (Angelus) were manipulated and placed into polyethylene tubes and immersed in distilled water. The pH of these solutions was measured at 24 hours, 7 days and 14 days. Simultaneously, at these same aforementioned periods, these materials' calcium releasing was quantified, through atomic absorption spectrophotometry. The results were submitted to ANOVA, with level of significance at 5%. Results: Concerning to pH, the materials present similar behaviors among each other at 24 hours (p > 0.05). At 7 and 14 days, MTA Fillapex® provided significantly lower pH values than the other materials (p < 0.05). Regarding to calcium releasing, at 24 hours and 7 days, MTA Fillapex® provided lower releasing than the other materials (p < 0.05). After 14 days, differences were found between MTA Fillapex® and gray MTA (p < 0.05). Conclusion: All materials showed alkaline pH and calcium releasing, with significantly lower values for MTA Fillapex® sealer.

Degree of conversion of different composite resins photo-activated with light-emitting diode and argon ion laser

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of ion irradiation on the structural properties and hardness of a-C:H:Si:O:F films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The crystal field strength parameter and the maximum splitting of the 7F1 manifold of the Eu3+ ion in oxides

We examine, from both the experimental and theoretical point of view, the behavior of the maximum splitting ΔE, of the 7F1 manifold of the Eu3+ ion as a function of the so-called crystal field strength parameter, Nv, in a series of oxides. In connection with the original theory that describes the relation between ΔE and Nv, a more consistent procedure to describe this relation is presented for the cases of small total angular momentum J. Good agreement is found between theory and experiment. © 1995.