In this study, pressed apricot (Prunus armeniaca L.) juice was concentrated using complex membrane technology with different module combinations: UF-RO-OD, UF-RO-MD, UF-NF-OD and UF-NF-MD. In case of the best combination a cross-flow polyethylene ultrafiltration membrane (UF) was applied for clarification, after which pre-concentration was done using reverse osmosis (RO) with a polyamide membrane, and the final concentration was completed by osmotic distillation (OD) using a polypropylene module. The UF-RO-OD procedure resulted in a final concentrate with a 65-70 degrees Brix dry solid content and an excellent quality juice with high polyphenol content and high antioxidant capacity.Nanofiltration (NF) and membrane distillation (MD) were not proper economic solutions.The influence of certain operation parameters was examined experimentally. Temperatures of UF and RO were: 25, 30, and 35 degrees C, and of OD 25 degrees C. Recycle flow rates were: UF: 1, 1.5, and 2 m(3) h(-1); RO: 200, 400, and 600 l h(-1); OD: 20, 30 and 40 l h(-1). The flow rates in the module were expressed by the Reynolds number, as well. Based on preliminary experiments, the transmembrane pressures of UF and RO filtration were 4 bar and 50 bar, respectively. Each experimental run was performed three times. The following optimal operation parameters provided the lowest total cost: UF: 35 degrees C, 2 m(3) h(-1), 4 bar; RO: 35 degrees C, 600 l h(-1), 50 bar; OD: 20, 30 and 40 l h(-1); temperature 25 degrees C.In addition, experiments were performed for apricot juice concentration by evaporation, which technique is widely applied in the industry using vacuum and low temperature.For description the UF filtration, a dynamic model and regression by SPSS 14.0 statistics software were applied.

An increase of industrial needs for micro-ablation and surface structuration using sub-picosecond laser working at high repetition rate is required. In this context, new industrial lasers were recently commercialized for such a type of purpose. The potential of a new industrial femtosecond laser source (Tangerine model from Amplitude Système) is investigated in this work for different etching purposes. Our experimental results will be also compared to those obtained when using Ti:Sa laser source, with the help of numerical simulations.

The largest quantities of by-products of dairy processing originates from the cheese making. Whey proteins are used for animal feeding and human nutrition as well, for example in dry soups, infant formulas, and supplements. The fat components of the whey might impair its use. The aim of our experiments was to investigate the separation of the lipid fraction of whey. The microfiltration is said to be a gentle and energy efficient method for this task. During the measurements 0.2 mu m microfiltration membranes were used and the membrane separation was enhanced by vibration, inserting static mixer and air sparging. The de-fatting efficiency, the retention of the whey components, the flux values, and the resistances in different combinations were compared in this paper.

This work presents the Continuous Wave (CW) laser crystallization of thin amorphous silicon (a-Si) films deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) and by Electron Beam Evaporation (EBE) on low cost glass substrate. The films are characterized by Elastic Recoil Detection Analysis (ERDA) and by Fourier-Transform Infrared (FTIR) spectroscopy to evaluate the hydrogen content. Analysis shows that the PECVD films contain a high hydrogen concentration (similar to 10 at.%) while the EBE films are almost hydrogen-free. It is found that the hydrogen is in a bonding configuration with the a-Si network and in a free form, requiring a long thermal annealing for exodiffusion before the laser treatment to avoid explosive effusion. The CW laser crystallization process of the amorphous silicon films was operated in liquid phase regime. We show by Electron Backscatter Diffraction (EBSD) that polysilicon films with large grains can be obtained with EBE as well as for the PECVD amorphous silicon provided that for the latest the hydrogen content is lower than 2 at.%. (c) 2012 Elsevier B.V. All rights reserved.

We present in this paper a comparison of the photodissociation processes of SiH 4 and Si 2 H 6 under pulsed excimer laser at 193 nm. The experimental curves of the gas composition as a function of laser energy density show that the dissociation of Si 2 H 6 results from both one and two-photon absorption whereas SiH 4 only absorbs two photons. The deposition yield of Si 2 H 6 has also been determined as a function of the number of laser pulses or initial pressure. These experimental results show the establishment of a stationary state in the gas phase and prove the existence of reverse reactions in the disilane kinetic model. The photodissociation of Si 2 H 6 under UV laser excitation (193 nm) presents, therefore, similar properties to those of SiH 4 .

Chemical doping of single-crystal silicon in a PF5 atmosphere is performed byirradiation with an ArF excimer laser working at 193 nm. We have investigated the dependence of doping parameters such as the number of pulses and PF5 gas pressure on the sheet resistance and the impurity concentration profiles. From these results, it is found that phosphorus atoms are produced by pyrolysis of PF5 molecules adsorbed (chemisorbed at low pressure and physisorbed at pressure higher than 1 Torr) on thesilicon surface. As for the incorporation mechanism, it is shown that the process is external rate limited for doping in PF5 ambient whereas mainly diffusion limitedfor doping using only the chemisorbed layer.

Our present understanding of the mechanisms of the transformation of SiO films under treatments in O2 or Ar plasma at room T, is presented. RBS, IR absorption, XPS, RHEED and TEM techniques have been used to investigate the composition, the chemical and structural nature of the films after oxidizing or non oxidizing treatments. In O2 plasma, SiO is converted into SiO2 by room T plasma anodization. The initial step of SiO oxidation, which is believed to be the transformation 2SiO→Si+SiO2, was studied in Ar plasma. We show that the as deposited SiO (not a mixture of Si and SiO2) is subject to disproportionate into the latter compounds and that the effects of irradiation by low energy electrons at room T (plasma treatment) are similar to those observed for high T treatments (rapid thermal annealing).

ABSTRACTThe incorporation properties of implanted or deposited Sb into the silicon lattice during laser irradiation with a UV laser has been studied. For both implanted or deposited Sb, we find a maximum substitutional concentration of 2.1 × 1021/cm3 following laser melting and solidification at V ; 6 m/sec. In both cases, substitutional solubility is limited by inter-facial instabilities which develop during regrowth. For the deposited case we observe in addition a much larger cellular microstructure which may result from convection induced instabilities.

We present a study of the temperature non-homogeneities induced by millisecond laser annealing in advanced CMOS technologies at die level. Because of the design, the device layout at the wafer surface introduces during this anneal significant spatial variations of optical absorption and heat transfer that can induce temperature non-uniformities over the die, often called ‘pattern effects’. These temperature variations are becoming a major issue, since they are the origin of significant device properties dispersion. A complete optical and thermal simulation set has been developed to estimate the temperature variations induced by the topologies at the wafer surface during the laser anneal process. The modelling has been validated by either a comparison with another software or reflectometry and electrical measurements on real structures. This work demonstrates that the temperature variations are caused either by optical coupling or by thermal properties dispersion present at the wafer surface at the anneal step. Finally, we demonstrate that the impact of the thin-film interferences and diffraction phenomena is the critical issue for these pattern effects.

We propose in this work a new approach, named laser-induced forward transfer, for the rapid deposition and patterning in a clean environment of high Tcsuperconducting thin films. A stoichiometric high Tc compound is initially deposited in a thin layer on an optically transparent support by laser evaporation or another more conventional technique. By irradiating under vacuum or in air the precoated layer with a strongly absorbed single laser pulse through the transparent support, we are able to remove the film from its support to be transferred onto a selected target substrate, held in contact to the original film. Using this technique, we have successfully transferred with one single pulse, provided by an excimer or a Nd:YAG laser, YBaCuO and BiSrCaCuO precoated thin films on various substrates. The Rutherford backscattering spectrometry experiments do not show any strong modification in the composition of the transferred layer against the source material, and the superconducting phases for the two types of compounds were obtained after subsequent thermal annealing carried out in a furnace around 850–900 °C in O2.For the BiSrCaCuO films transferred onto MgO substrates, we have measured an onset critical temperature of about 90 K with a zero resistance at 80 K.

Lithium niobate thin films were deposited on sapphire substrate by radio-frequency magnetron sputtering technique. One and two dimensional structures have been made using a KrF excimer laser at 248nm and 6ns pulse width, under various conditions of ablation, in order to assess the applicability of laser direct-writing of photonic waveguides. The optical and waveguiding properties of LiNbO3 thin films were studied by prism-coupling technique, while micro-Raman spectroscopy was used for structural and composition characterization, as well as laser processing mechanism investigation. The surface morphology of the processed structures was obtained by a Nomarski optical microscope, an atomic force microscope and a White Light Interferometer Microscope.

The purpose of this work is to determine the optimal parameters required to crystallize thin amorphous silicon films on glass substrate with a continuous wave (CW) laser diode (λ=808nm), using a numerical model developed in COMSOL Multiphysics. The numerical simulation of the laser crystallization process takes into account the solid–liquid phase change and the difference between the melting temperature of amorphous (Tma-Si=1420K) and that of crystalline silicon (Tmc-Si=1690K). We have varied the main parameters controlling the crystallization process, namely the power and the scan speed of the laser beam. Furthermore the initial temperature as well as the thickness of the a-Si:H layer were also taken as a parameter to optimize the process. We have determined the melting, crystallization and ablation energy threshold versus the different operational parameters.

Due to the continuous CMOS transistor scaling requirements, highly doped shallow junctions with improved activation have been widely investigated in recent CMOS technologies. In this scope, sub-melt millisecond laser annealing has been introduced in the integration flows to enhance dopant activation, without any additional detrimental diffusion. This MSA step impacts not only the transistor junction properties, but also the polysilicon gate depletion. This paper is devoted to the study of the MSA influence on boron and germanium co-implanted polysilicon films. A sensitive boron diffusion occurring during the laser anneal step, with or without an initial spike annealing step, has been observed. The activation energy of the boron diffusivity extracted from SIMS profiles in the laser only sequence has been found equal to 4.05eV. In addition, it was shown that either a high temperature laser anneal sequence or a spike anneal followed by a laser anneal sequence can reach the same activation levels.

In this study, nanofiltration (NF) and reverse osmosis (RO) were used in laboratory scale to concentrate As containing wastewater. Cross flow membrane filtration apparatus was applied in batch mode with recycling the retentate. Then the retentate of membrane filtration was treated with lime (Ca(OH)2) and sulfur hydrogen (H2S) to help the precipitation for producing clean water and a low volume, highly concentrated As waste.

Due to the continuous CMOS transistor scaling requirements, sub-melt millisecond laser annealing has been introduced in 45nm CMOS technology to enhance dopant activation without any additional diffusion. Because of the design, the device layout at the wafer surface introduces during this process significant variations of optical absorption and heat transfer that can induce temperature non-uniformities over the die, detrimental to the device and often called “pattern effects”. The introduction of an absorbent layer above the wafer reduces the optical properties dispersion, but the temperature variations generated by the thermal properties non-homogeneities cannot be suppressed. The impossibility to measure directly this local transient temperature effects on complex transistors layout requires simulation. A thermal simulation has been developed and calibrated to model with accuracy the laser annealing with the real process parameters. This model is used to obtain the transient temperature distribution over the devices, which is needed to understand the laser impact on the transistors performance. We demonstrate that the shallow trench isolation (STI) filled with silicon oxide is critical for these thermal pattern effects. Depending on the STI layout density, temperature variations up to 50°C over a die are observed.

In this work, we report on the fabrication and characterization of surface microstructures in lithium niobate thin films and single crystal by using KrF excimer laser ablation technique at 248nm with 6ns pulse width. Ablation is carried out through a mask projection set-up. Various experimental conditions are used in order to evaluate the potential of laser direct writing for photonic waveguides fabrication in lithium niobate. The surface morphology of the processed structures was studied by optical and atomic force microscopy. Laser processing mechanism is investigated by using micro-Raman spectroscopy.

Excimer laser processing appears very promising to prepare at low temperature high quality polysilicon TFTs for active matrix display applications. In this work, the specific advantages of a large area (similar to 20 cm(2)) and long-pulse duration (200 ns) excimer source (VEL from SOPRA) both for crystallization of the silicon thin film (50 - 100 nm) on SiO2-coated glass substrates and for doping of source and drain regions of the TFT, are reviewed.