We have carried out in-situ measurements of cluster volume fraction in silicon films during deposition by using quartz crystal microbalances (QCM’s) together with a cluster-eliminating filter. The cluster volume fraction in films is deduced from in-situ measurements of film deposition rates with and without silicon clusters using QCM’s. The results show that the higher deposition rate leads to the higher volume fraction of clusters.

The polycrystalline n+/intrinsic silicon thin film stacks with various original intrinsic amorphous silicon layer thicknesses were formed using the multiple pulsed rapid thermal annealing process with the Ni-induced crystallization mechanism. The thick polycrystalline silicon stack was prepared by repeated steps of 1) amorphous silicon thin film deposition, 2) solution oxidation, 3) dehydrogenation, 4) pulsed rapid thermal annealing, and 5) oxide stripping. The poly-Si film properties, such as the grain size, orientation, and volume fraction of the crystalline phase, were related to the original intrinsic silicon film thickness and the total thermal budget. This process is effective in preparing the high volume fraction polycrystalline silicon thin film, which is important for low-cost thin-film solar cells, electronic and optoelectronic devices.

Plutonium oxide heat sources are used to power space missions. The heat produced by alpha decay of the 238 isotope of Pu is converted to electricity in a thermopile, providing electricity during a substantial fraction of the 88 year half-life of the isotope. Decay of the Pu produces helium and uranium, and a fraction of the evolved helium is captured in the oxide matrix. All of the helium produced in decay can in principle be contained in the oxide lattice, where it occupies the tetrahedral sites. Some helium diffuses out at a rate that is somewhat dependent on the form and morphology of the fuel. Rates have previously been measured for oxide aged about 1 year. Current measurements on sealed heat sources as old as 34 years indicate that the rate of diffusion has changed only slightly over time. Possible mechanisms for helium release include bubble diffusion, point defect migration, agglomeration and movement of He at grain boundaries, and volume diffusion through the lattice sites. We observe primarily diffusion from site to site within the lattice, with an activation energy of 18.7 kcal/mole, independent of point defect movement, despite the rising concentration of helium in the lattice over time and the accumulation of radiation damage within the lattice. Because of the slow diffusion of helium from the fuel to the headspace, heat sources are anticipated to be stable over a long lifetime.

A roast experiment was carried out by using vanadium stone coal from Hubei Province as object, in the condition of compound additive dosage is 6%, the effects of roasting temperature, roasting time and material size on vanadium lixiviate efficiency were investigated. Experimental results indicate that, for the vanadium stone coal from Hubei Province, at the condition of additive dosage is 6%, the ideal target of vanadium lixiviate efficiency 82.3% can be acquired in the optimum condition of roasting temperature at 850 oC, roasting time is 120 minutes, material size is minus 0.5mm.

Level set methods have been used for Solid phase epitaxial regrowth, etching and deposition.This study is to model the growth of nickel silicide accurately using the level set method. NiSi growth has been observed to follow a linear-parabolic law which takes into account both diffusion and interfacial reaction. This linear-parabolic system is very similar to the Deal and Grove model of SiO2 growth. This model uses similar diffusion transport and reaction rate equations. This simulation models the growth of silicide coupling diffusion solutions to level-set techniques. Dual level sets have been used for top and bottom interface propagation of silicide; velocities were estimated based on nickel concentrations at both interfaces as well as diffusivity and reaction rate of nickel. This is important to predict precise shape of silicide that will allow current crowding and field focusing effects to be modeled in transport out of the intrinsic device into the contacting layers. These simulation models can be used for latest technology nodes at 45, 32, 22nm and special devices such as FinFET’s etc. The level set method is successfully implemented and verified in Florida Object Oriented Process Simulator and growth shapes matches well with the literature Transmission Electron Microscopy data.

We have investigated some diamondoids encapsulation into single walled carbon nanotubes (with diameters ranging from1.0 up to 2.2 nm) using fully atomistic molecular dynamics simulations. Diamondoids are the smallest hydrogen-terminated nanosized diamond-like molecules. Diamondois have been investigated for a large class of applications, ranging from oil industry to pharmaceuticals. Molecular ordered phases were observed for the encapsulation of adamantane, diamantane, and dihydroxy diamantanes. Chiral ordered phases, such as; double, triple, 4- and 5-stranded helices were also observed for those diamondoids. Our results also indicate that the modification of diamondoids through chemical functionalization with hydroxyl groups can lead to an enhancement of the molecular packing inside the carbon nanotubes in comparison to non-functionalized molecules. For larger diamondoids (such as, adamantane tetramers), we have not observed long-range ordering, but only a tendency of incomplete helical structural formation.

The electrochemical reduction of H2O2 on SIMFUEL was investigated over the pH range 1 to 4. The mechanism at pH 4 is known to occur on UV species incorporated into a surface layer of UIV 1-2xUV 2xO2+x. However, below pH 3, reduction occurs on an adsorbed UVO2(OH) state which is unstable and oxidizes to insulating UVI before dissolving as UO2 2+. Both schemes are observed at intermediate pH’s. The presence of both low and high acidic regions at the electrode surface is determined by the combination of peroxide concentration, bulk pH and the surface diffusion conditions.

The potential of chemically derived graphene as a solution-processable transparent conductive film has been explored. Synthesis of amine-functionalized graphene oxide was intended for its utilization in layer-by-layer assembly. Layer-by-layer assembly of graphene oxide was utilized to fabricate graphene based thin film in a scalable and highly reproducible way. It was found that optical transmittance and sheet resistance of the film decreases with an increase in number of LBL cycles in a reproducible way. The sheet resistance of LBL-assembled GO film improves by an order of magnitude at the same optical transparency due to more homogeneous coverage and better stacking of graphene flakes. Furthermore, we demonstrated the potential for a large-scale deposition of chemically derived graphene.

SiGe nanowires of different Ge atomic fractions up to 15% were grown and ex-situ n-type doped by diffusion from a solid source in contact with the sample. The phenomenon of dielectrophoresis was used to locate single nanowires between pairs of electrodes in order to carry out electrical measurements. The measured resistance of the as-grown nanowires is very high, but it decreases more than three orders of magnitude upon doping, indicating that the doping procedure used has been effective.

Potassium (K) ions have been implanted in hydrothermally grown ZnO to a dose of 1 × 1015 cm-2, followed by isochronal annealing in a tube furnace (30min) and by rapid thermal annealing (30s) on two separate samples. For annealing temperatures below 700°C, only a minor redistribution of Li is observed behind the projected range of the K+ ions. At temperatures between 700 and 750°C, however, both annealing treatments show a wide region behind the implantation peak which is depleted of Li, and this depletion is used as a tracer to monitor diffusion of intrinsic defects like the Zn interstitial. The results are interpreted as Zn interstitials being released from the implanted region in a burst at temperatures above ∼700°C, followed by rapid migration, replacement of Li on Zn site through the kick-out mechanism, and migration of Li away from the active region.

At present, the industrial sector requires the recovery of tool steel componentssubjected to severe wear which are built with steel HWS these have the sameproperties in all tribology directions and have great success in buildingtooling. In this paper, we recover the previously HWS steel machining with afillet of 2mm caused by the metallurgical recovery of the component, applyingthe process of plasma transferred arc PTA which has very good fats dilutionproperties in comparison to other conventional processes currently applied forthe recovery of tooling, such as GTAW, SMAW, SAW. The experiment was conductedwith input D2 and M2 with one and two welding seams, making the assessmentmetallography, hardness and wear tests pin-on-disk. Finding a decrease in thehardness of the interface line, according to the evaluation of wear pin-on-disk,had a higher wear rate of the filler metal in the M2 D2.

Differentiated neurons (dorsal root ganglia and cortical neurons) have been shown to develop longer neurite extensions on softer materials than stiffer ones, but previous studies do not address the ability of neural stem cells to undergo differentiation as a result of material elasticity. In this study, we investigate neuronal differentiation of C17.2 neural stem cells due to growth on polyacrylamide gels of variable elastic moduli. Neurite growth, synapse formation, and mode of division (asymmetric vs. symmetric) were all assessed to characterize differentiation. C17.2 neural stem cells were seeded onto polyacrylamide gels coated with Type I collagen. The cells were then serum starved over a 14 day period, fixed, and analyzed for biochemical markers of differentiation. For division studies, time-lapse imaging of cells on various substrates was performed during serum withdrawal using the Nikon Biostation. Division events were analyzed using ImageJ to quantify sizes of resulting daughter. Data shows that C17.2 cell differentiation (as dictated by number and type of division events) is dependent upon substrate stiffness, with softer polyacrylamide surfaces (140 Pa) leading to increased populations of neurons and increased neurite length. Our data also indicates that the ability of neural stem cells to express synaptic proteins and develop synapses is dependent upon material elasticity.

Inkjet printing of alternate layers of anionic and cationic polyelectrolytesallows organized gels to form with structures similar to those made bylayer--by-layer dipping methods but very much faster. Structures of gelsformed using slow and fast inkjet printing systems are compared usingelemental analysis, swelling and diffusion kinetics as characterizationmethods. After printing and washing, most sodium or chloride counter-ionsare last from the gel, leave only the polymer complex. The swellingproperties of the printed and washed gel depend on the deposition rate andon the ratio of the two polymers as originally printed. The syntheticpolyelectrolytes reported here can be compared with biologicalpolyelectrolytes reported earlier by us.

Research reactors spent fuels disposal is a problematic area that conduces to the quest of feasible solutions for ensure safe destination of the spent fuels. In this work, a new method for processing spent fuel from MTR reactors is presenting. The main objective of this process, is the immobilization of principal radioactive elements that are present in the spent fuel, in order to achieve a suitable material which could be temporally stored safely. The Vitrocerus method involves ordinary physical procedures performed in a hot cell. It differs from conventional vitrification because there is a reduction in volume of glass material added.

The process propose the ceramization of a mixture of spent fuel plates (wich were milled and calcined previously) with natural uranium oxide (U3O8) to obtain the desired isotopic dilution (to low the U235 enrichment). At the same time, a small fraction of VG98/12 glass [1] was added to enhance low temperature sintering. The treatment and conditioning tasks proposed in Vitrocerus were tested on MTR fuel miniplates that simulate a real U3Si2 dispersed in Al fuel, which were successfully transformed into ceramic sintered pellets [2,3] with low enrichment, structural integrity, outstanding mechanical properties and water corrosion resistance. Eventually these pellets could be stored safely in an interim dry storage facility.

A high molecular weight, photocurable inorganic-organic hybrid based on ladder-like poly(phenyl6-co-methacrylate4)silsesquioxanes (LPPMA64) was investigated as a flexible display substrate. Photocured free standing films with 40μm thickness showed high transparency (>95%), excellent thermal stability (Td >450°C), and low coefficient of thermal expansion (38ppm/K) without the use of reinforced glass fibers. Furthermore, these ladder-like structured materials did not require any thermal treatment processes due to the negligible amounts of uncondensed groups, thus simplifying manufacturing processing. These novel hybrid films present an alternative to organic plastics as flexible electronic device substrates due to their excellent optical and thermal properties.

In this paper, a Particle Swarm Optimization (PSO) algorithm is presented to find the optimal combination of corrosion rate parameters for a refining process in the oil industry. The experimental data in this paper are constituted by results obtained from field tests. Maintenance control is a very important aspect in order to prevent substantial damage to facilities, equipment and people. Other important factor to consider is the cost of maintenance which tends to reduce the required actions. The main parameters in corrosion control are flow, concentration of sulfur species, total acid number (TAN), temperature, and chromium content. However it is not easy to know the combined effect of different variables due to synergistic effects. Particle swarm optimization (PSO) is a population based stochastic optimization technique, inspired by social behavior of bird flocking or fish schooling. The system is initialized with a population of random solutions and searches for optima by updating generations. In PSO, the potential solutions, called particles, fly through the problem space by following the current optimum particles.

Emerging NVM devices have been extensively studied as candidates to extend density scaling and power reduction beyond Si-based flash. Recently, resistive-random-access-memory (ReRAM) devices in the form of metal-insulator-metal (MIM) structures have attracted substantial attention due to their potential scalability, low power operation, and high speed. HfO2 is attractive compared to other transition metal oxides from the vantage point of CMOS process compatibility. Here, we investigate doped HfO2 with a Pt top electrode on an n+-Si substrate. By doping HfO2 with Hf or Au, improved resistive switching properties have been demonstrated in terms of enhanced cycling endurance and lower switching voltages for SET and RESET. The improvements were attributed to doping-induced oxygen vacancies. In addition, Cu-doped HfO2 devices have exhibited multilevel resistive switching.

Inorganic erbium-doped glasses are widely used in telecommunications due to the sharp intra-atomic 4I13/2 → 4I15/2 transition in the 4f orbital of erbium resulting in an emission at ∼ 1.5 μm, which is the low loss window of silica optical fibres. The limited erbium concentration of about 1020 ions/cm3 in inorganic erbium-doped glasses and the low absorption coefficient of the Er3+ ions, imply that relatively long lengths of fibre are required. Organic erbium complexes present higher absorption cross sections due to the photosensitization of erbium by the organic conjugated ligands and broader emission bands than those of the free Er3+ ions. Such properties open the possibility to develop compact, low power and broadband infrared emitting devices. We present the study of an organic fluorinated erbium complex exhibiting 1.5 μm luminescence lifetime of several hundreds of microseconds measured on thin film. The organic complex has been deposited by vacuum sublimation technique. This deposition method allows the realization of an erbium-doped thin film without the help of an organic polymer matrix, which is a potential source of vibrationnal luminescence quenching. We report the synthesis, the sublimation process, and the characterization of the thin films. The chemical structure of the complex is assessed by FTIR, NMR and MALDI-TOF. Chemical integrity of the thin film after vacuum deposition is determined by FTIR. The morphology of the thin film is characterized by X-ray diffraction experiments. The optical properties of the thin film are determined by spectroscopic ellipsometry, UV-Vis-NIR absorption spectroscopy and time resolved NIR photoluminescence spectroscopy.