Deposition of tin oxide, iridium and iridium oxide films by metal-organic chemical vapor deposition for electrochemical wastewater treatment

In this research, the specific electrodes were prepared by metal-organic chemical vapor deposition (MOCVD) in a hot-wall CVD reactor with the presence of O2 under reduced pressure. The Ir protective layer was deposited by using (Methylcyclopentadienyl) (1,5-cyclooctadiene) iridium (I), (MeCp)Ir(COD), as precursor. Tetraethyltin (TET) was used as precursor for the deposition of SnO2 active layer. The optimum condition for Ir film deposition was at 300 °C, 125 of O2/(MeCp)Ir(COD) molar ratio and 12 Torr of total pressure. While that of SnO2 active layer was at 380 °C, 1200 of O2/TET molar ratio and 15 Torr of total pressure. The prepared SnO2/Ir/Ti electrodes were tested for anodic oxidation of organic pollutant in a simple three-electrode electrochemical reactor using oxalic acid as model solution. The electrochemical experiments indicate that more than 80% of organic pollutant was removed after 2.1 Ah/L of charge has been applied. The kinetic investigation gives a two-step process for organic pollutant degradation, the kinetic was zero-order and first-order with respect to TOC of model solution for high and low TOC concentrations, respectively

Fluoxetine Exerts Age-Dependent Effects on Behavior and Amygdala Neuroplasticity in the Rat

The selective serotonin reuptake inhibitor (SSRI) Prozac® (fluoxetine) is the only registered antidepressant to treat depression in children and adolescents. Yet, while the safety of SSRIs has been well established in adults, serotonin exerts neurotrophic actions in the developing brain and thereby may have harmful effects in adolescents. Here we treated adolescent and adult rats chronically with fluoxetine (12 mg/kg) at postnatal day (PND) 25 to 46 and from PND 67 to 88, respectively, and tested the animals 7–14 days after the last injection when (nor)fluoxetine in blood plasma had been washed out, as determined by HPLC. Plasma (nor)fluoxetine levels were also measured 5 hrs after the last fluoxetine injection, and matched clinical levels. Adolescent rats displayed increased behavioral despair in the forced swim test, which was not seen in adult fluoxetine treated rats. In addition, beneficial effects of fluoxetine on wakefulness as measured by electroencephalography in adults was not seen in adolescent rats, and age-dependent effects on the acoustic startle response and prepulse inhibition were observed. On the other hand, adolescent rats showed resilience to the anorexic effects of fluoxetine. Exploratory behavior in the open field test was not affected by fluoxetine treatment, but anxiety levels in the elevated plus maze test were increased in both adolescent and adult fluoxetine treated rats. Finally, in the amygdala, but not the dorsal raphe nucleus and medial prefrontal cortex, the number of PSA-NCAM (marker for synaptic remodeling) immunoreactive neurons was increased in adolescent rats, and decreased in adult rats, as a consequence of chronic fluoxetine treatment. No fluoxetine-induced changes in 5-HT1A receptor immunoreactivity were observed. In conclusion, we show that fluoxetine exerts both harmful and beneficial age-dependent effects on depressive behavior, body weight and wakefulness, which may relate, in part, to differential fluoxetine-induced neuroplasticity in the amygdala

A TWO DIMENSIONAL MODEL FOR LPCVD REACTORS HYDRODYNAMICS AND MASS TRANSFER

Cet article présente un modèle bidimensionnel qui analyse, en détail, l'hydrodynamique, les phénomènes de transport de matière et de réactions chimiques au sein des réacteurs de LPCVD. Il développe et discute deux cas particuliers correspondant aux dépôts de silicium polycristallin pur et de silicium polycristallin dopé in situ au phosphore. Les résultats mettent en évidence la complexité des phénomènes impliqués et, tout particulièrement, l'importance des réactions homogènes dans la phase gaz.A two dimensional model analyzing in great details the hydrodynamics, mass transport and chemical reactions inside LPCVD reactors is proposed. Two different applications in the cases of depositions of pure polysilicon and of phosphorus in situ doped polysilicon are developed and discussed. The results put in evidence the complex phenomena involved and, particularly, the importance of the homogeneous reactions in the gas phase

Economical Analysis and Optimization of a Low Pressure Chemical Vapor Depositioni (LPCVD) Reactor

An economical analysis of the LPCVD hot wall tubular reactor functioning is presented including equipment amortization, clean room location, supplies, maintenance, labor, gas and energy consumption. From a technical point of view, CVD1 model is used to characterise the phenomena involved during polysilicon deposition, linking growth rate distribution to operating conditions. An optimization is then realized in three different cases with and without a temperature profile. By this study the main costs of CVD operation such as gases consumption and equipment amortization are identified, and the total cost has been drastically reduced by using a temperature profile

Épuration des eaux de rinçage d'une chaîne de chromage avec minimisation des boues formées

ln the case of chromium plating unit, metals polluting in waste waters are trapped by precipitation in the form of hydroxides. To generate a minimal sludge volume and also equally to be able to recycle the rinsingwater, the electrochemical technique of in situ generation of hydroxides is used, studied and developed.Les métaux polluants contenus dans les eaux de rinçage des chaînes de chromage, sont piégés par précipitation sous forme d'hydroxydes. Pour générer un volume minimal de boues et pour également pouvoir recycler l'eau de rinçage, la technique électrochimique de génération in situ d'hydroxydes est utilisée, étudiée et mise au point

A NOVEL WAFER CAGE FOR BETTER UNIFORMITY OF PHOSPHORUS DOPED SILICON LAYERS : EXPERIMENTAL STUDY AND MODELLING

The deposition of in situ phosphorus doped polycrystalline silicon, an operation which involves complex physico-chemical phenomena, has been treated via both a modeling and an experimental approach. This analysis has contributed to provide better insights in the mechanism of phosphorus doped polysilicon deposition and has helped to design a new kind of a wafers cage, improving considerably the growth rate uniformity on each substrate

On the behavior of rapid thermal CVD reactors

Two mathematical models are developed and applied to RTCVD reactors. They involve the resolution of momentum, heat and mass transfer equations with homogeneous and heterogeneous chemical reactions. A detailed discussion about the effects of some physical parameters is undertaken so that a fundamental understanding of gas flow patterns and the contribution of each chemical species to the deposition of polysilicon is obtained

Reactor Modelling and Analysis of Amorphous Hydrogenated Silicon Deposition by PECVD

The behaviour of plasma reactors is complex and affected by a large number of parameters (temperature, pressure, flow rates, power, frequency, etc...). In that context, modeling constitutes a very convenient theoretical approach to analyze the complex parameters influences on the reactors overall performances, in the particular case studied here, amorphous hydrogenated silicon deposition rate profiles on the substrates. This particular study is devoted to a detailed analysis of the reactor behaviour in higher electrical power conditions. It demonstrates that, if relatively simple mechanisms for electron-molecule interactions and gaz phase reactions can be used in low power conditions, this do not remain true in higher power conditions where a great number of reactions must be taken into account