Diffusion and sorption of cesium (Cs) and iodine (I) were investigated in a purified and moderately compacted sodium montmorillonite (dry density of 800 kg m-3) saturated with 0.01, 0.1 and 0.5M NaCl solutions. The effective diffusivity (De) and capacity factor (α) for Cs and I were measured by through-diffusion experiments, coupled with multiple curve analyses, including tracer depletion, breakthrough and depth concentration curves, which could be fitted with a conventional diffusion model using only one set of parameters. The De values obtained for Cs were of the order of 10-9-10-10 m2 s-1 and decreased as salinity increased, and those for I were of the order of 10-11-10-12 m2 s-1 and showed the opposite dependency. The distribution coefficient (K d) of Cs decreased from the order of 100 to 10-2 m3 kg-1 as salinity increased. Diffusion and sorption parameters for Cs were also obtained by in-diffusion and batch sorption experiments and showed good agreement with those obtained by the through-diffusion experiments. The diffusion model, based on homogeneous pore structure and electrical double layer (EDL) theory, predicted the salinity dependence of De reasonably well, showing the effect of cation excess and anion exclusion as a function of salinity. The apparent diffusivity (D a), which includes sorption effects, was also interpreted by a coupled sorption model.

Platinum (Pt) nanoparticles were prepared on a glassy carbon plate by a sputtering method and then irradiated with proton (H+) beams at energies of 0.38 and 10 MeV at room temperature. Cyclic voltammetry in an aqueous 0.5 mol/dm3 H2SO4 solution suggested that the lower-energy beam irradiation enhanced the active surface area of the Pt nanoparticles, calculated from the coulombic charge for hydrogen desorption. Thus, the nanoparticles would be modified by H+ beam-induced electronic excitation so that they have higher surface activity. The mechanism of this irradiation effect seems to be rather complicated and is still unclear at present, but we may discuss it in relation to a change in the interfacial crystal structure during the irradiation.

FINEMET-type (Fe75Si15NbBCu) ribbons were heat treated, and their magnetic properties were analyzed. Permeability, thermal, and mechanical sensitivities were measured by commonly used industrial methods, and these properties were correlated with measured magnetic Barkhausen noise parameters. Distributions of peak area, A, and peak noise energy, E, were evaluated. Distribution functions of noise parameters, P(x), were in good agreement with the theory of self-organized criticality (SOC), satisfying power laws in the form P(x)∼x−α. It is found that the noise did not considerably depend on the temperature sensitivity parameter and on the permeability of ribbons. However, a useful correlation between the noise parameters and mechanical sensitivity has been observed. Minimal noise was detected for samples with negligible mechanical sensitivity in an amorphous-nanocrystalline composite state obtained by a heat treatment at 853 K.

We perform large-scale finite-difference time-domain (FDTD) simulations with the aid of efficient parallel-computing algorithms for designing optical and acoustic metamaterials, where either electromagnetic or elastic constants in the materials are artificially modulated via nano/micro-structuring.

For optical metamaterials, effects of nanostructure on dielectric properties are taken into account by introducing the Drude-Lorentz model and a hybrid quantum-mechanical/classical FDTD method for optical dispersion of simple metal particles. Using these computational methods, we assess the materials dependence of light-confinement efficiency in the recently proposed novel structure that combines dielectrics and metamaterials periodically.

In the acoustic case, we perform the parallel FDTD simulations of elastic-wave propagations in 2D phononic crystals. The negative refraction of acoustic wave is shown to occur via a negative effective mass appeared in their phonon band-structures. We demonstrate that the focal intensity by the lens effect and its energy-transfer efficiency can be optimized by adapting the filling fraction of the crystal.

Single-walled carbon nanotubes (SWCNTs) prepared by the HiPco process were purified using a modified gas phase purification technique. A TEM-STM holder was used to study the morphological changes of SWCNT ropes as a function of applied voltage. Kink formation, buckling behavior, tubular transformation and eventual breakdown of the system were observed. The tubular formation was attributed to a transformation from SWCNT ropes to multi-walled carbon nanotube (MWCNT) structures. It is likely mediated by the patching and tearing mechanism which is promoted primarily by the mobile vacancies generated due to current-induced heating and, to some extent, by electron irradiation.

The effect of porosity on the radiation component of the thermal conductivity of the thermal barrier coatings is studied. Heat transfer in the disordered porous structures as well as the porous photonic band-gap structures is investigated. The pores, which size is comparable with the characteristic radiation wavelength λmax=2897.8/T μm, were found to be most efficient obstacles for the heat radiation.

We describe a new class of plasmonic photonic crystal emitters integrated into a MEMS platform for high temperature-intensity, high speed, and high efficiency tuned emitting and sensing applications in the infrared. We exploit 2D organized metallo-dielectric surface structures for angular and spectral control of reflection, absorption and emission from surfaces in the infrared. We have built a FDTD model that incorporates complex frequency dependent properties and provides quantitative agreement with measured spectral data. High temperature materials and special fabrication techniques allow high temperature operation. This technology offers new solutions for spectral control with application in thermophotovoltaic (TPV) energy conversion. Built on a MEMS platform, for thermal isolation from the environment, these devices also modulate at high speed, opening new applications in spectroscopy, infrared imaging, and signaling. Demonstrated wafer-level vacuum sealing improves the wall plug efficiency dramatically. We describe device architecture and fabrication considerations for plasmonic photonic crystal structures which simultaneously act as emitters and sensors in a defined narrow waveband radiation. In particular, this combined capability opens new avenues for research for vital commercial applications such as environmental protection, household safety, bio-hazardous material identification, meteorology and industrial environments.

The storage principal of the Electrochemical Metallization Memory Cell is based on change of cell resistance induced by electro-chemical driven growth and rupture of a cupric or silver filament in an insulating matrix. This kind of switching was found in several materials as AgGeSe, CuGeS, silicon oxide or tungsten oxide [1].

During write operation copper or silver is oxidized at the corresponding electrode and copper or silver ions are driven out of the copper or silver anode into the insulating matrix due to the applied field, whereas the insulating matrix serves as solid electrolyte. The silver or copper ions migrate towards the cathode. At the cathode electrochemical reduction occurs, and deposition of metallic copper or silver takes place. Fast diffusion paths in the solid electrolyte matrix or preferred nucleation sites (seeds) at the boundary lead to filamentary growth. This growing cupric or silver dendrite finally reaches the anode and switches the device to a low resistance state.

Based on this switching mechanism a FEM simulation model was set up. To simplify the model space charges due to silver or copper migration are neglected. It is further assumed, that the conductivity in the solid electrolyte is only ionic. Hence, it is sufficient to solve the well-known Laplace equation to address the electric properties as well as ion migration. A “Level Set” method is used to track the boundary of the growing filament. The velocity of this boundary is proportional to the ionic current density calculated by Laplace equation. Based on this model simulations are applied to cell structures with multiple fast diffusion paths and seeds. Simulation results show that just one filament reaches the anode.

In a second step, Butler-Vollmer boundary conditions are introduced. This nonlinearity leads to an exponential dependence between switching time and switching voltage. As switching voltage increases, switching time decreases.

A simulation model capable of simulating ECM memory cells is presented. The model enables to simulate the behaviour of different cell geometries or different materials as solid electrolyte. Furthermore it gives deeper insight into the switching mechanism.

This work was supported by the European project EMMA “Emerging Materials for Mass storage Architectures” (FP6-033751).

Cost benefit analysis (CBA) and energy profit ratio (EPR) indicate that third generation PV should be high-throughput ones with higher efficiency than CdTe PV. The polymer photovoltaics (OPV) such as PCBM/P3HT, and the dye-sensitized solar cells (DSC), i.e. TiO2/dyes/iodide-iodine-electrolytes will be reviewed as printable PV to cope in near future with environmentally benign PV demand. The recent progress of OPV and DSC will be discussed in terms of diffusion length, and our recent studies on iodine-free DSC. The OPV-DSC-hybridized PV exemplified by solid-state Dye/TiO2/P3HT will become hopeful as printed thin-film solar cells, in particular when the conversion efficiency is further enhanced more than 10%.

A novel end-point detection method based on a combination of shear force and its spectral amplitude was proposed for barrier metal polishing on copper damascene structures. Under some polishing conditions, the shear force changed significantly with polished substrate. On the other hand, the change in shear force was insignificant under certain polishing conditions. Therefore, a complementary end-point detection method by monitoring oscillation frequency of shear force was proposed. It was found that the shear force fluctuated in unique frequencies depending on polished substrates. Using Fast Fourier Transformation, the shear force data was converted from time domain to frequency domain. The amplitude of spectral frequencies corresponding to the rotational rate of wafer carrier and platen was monitored. Significant frequency amplitude changes were observed before, during and after the polished layer transition from barrier film to silicon dioxide film. The results indicated that a combination of shear force and its spectral amplitude analyses provided effective end-point detection for barrier CMP process.

For the first time, we discuss the compatibility of stress proximity technique (SPT) with dual stress liner (DSL) in high-κ/metal gate (HK/MG) technology. The short-channel mobility enhancement and the drive current improvement brought by SPT have been demonstrated at 32nm technology node. With maintained short channel control and threshold voltage roll-off characteristics, SPT has achieved 7% drive current improvement for both nFET and pFET from the optimization of SPT with DSL.

This work is devoted to a study of the conformational properties of alanine dipeptide. We have studied potential energy surfaces of alanine dipeptide molecule using density functional theoretical approach with 6-311G basis set. For this purpose potential energies of this molecule are calculated as a function of Ramachandran angles φ and ψ, which are important factors for the characterizations of polypeptide chains. These degrees of freedoms φ and ψ are important for the characterization of protein folding systems. Stable conformations, energy barriers and reaction coordinates of this important dipeptide molecule are calculated. Energy required for the transition of one conformation into other are also discussed.

We report here the synthesis of tin disulfide nanotubes by a vapour liquid solid growth using bismuth, a low melting metal, as a catalyst. The reaction was carried out in a single step process by heating SnS2 and bismuth in a horizontal tube furnace at 800oC. TEM analysis allowed proposing a plausible mechanism for the formation of SnS2 nanotubes. Pure material could be obtained by optimizing the reaction based on a product analysis using powder X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) combined with energy dispersive X-ray spectroscopy (EDX).

A new type of flow-through test method using micro-reactor was developed and applied to measurement of the dissolution/alteration kinetics for a Japanese type of simulated HLW glass, P0798. In this test method, a face of coupon shaped glass specimen (30mm × 10mm × 4mm size) is in contact with a micro-channel (20mm length, 2mm width, 0.16mm depth) constructed on a PTFE (Teflon®) plate, and a solution is injected into the inlet of micro-channel at a constant rate. The injected solution, which flows through the micro-channel reacting with the glass to the outlet, is retrieved at certain intervals to be analyzed for determination of the glass dissolution/alteration rate. After the test, the glass specimen removed from the micro-reactor is subjected to surface analyses. This test method has major features as follows, 1) any controlled solution condition can be provided over the test duration, 2) a relatively high S/V ratio can be provided by use of micro-reactor in spite of using coupon shaped glass specimen, which results in precise and consistent analyses of both the solution and the reacted glass surface, 3) the test apparatus is simple with compact size and easy operation, which allows a flexible setup of test conditions. By use of this test method the dissolution/alteration rate for P0798 glass was measured as a function of pH, temperature, and time, and the results indicated that this test method is applicable and suitable for evaluation of the dissolution/alteration kinetics.

The general design principle of shape-memory polymers (SMP) requires two key compo-nents: covalent or physical crosslinks (hard domains) determining the permanent shape and switching domains fixing the temporary shape as well as influencing the switching temperature Tsw. In conventional thermoplastic SMP hard and switching domains determining segments are combined in one macromolecule, e.g. block copolymers such as polyurethanes. Recently, binary polymer blends having shape-memory properties, from two different multiblock copolymers have been presented, whereby the first one is providing the segments forming hard domains and the second one the segments forming the switching domains. Besides the shape-memory proper-ties, the mechanical properties of such materials are application relevant. Here we investigate how the blend composition influences mechanical properties of this new class of shape-memory materials.

Cementitious materials are widely used in waste management systems with different aims and requirements for long term performance. Both conventional and novel cementitious materials are used to create reliable immobilising elements for safe storage and disposal of wastes. The barrier elements as well as interactions envisaged between various components are important to ultimately ensure the overall safety of a storage/disposal system. The behaviour and performance of cementitious materials including waste package components, wasteform and backfilling were analysed within the IAEA Coordinated Research Project which involved 26 research organizations from 21 Member States MS). The paper presents briefly the main research outcomes for conventional cementitious systems; novel materials and technologies; testing and waste acceptance criteria; and modelling long term behaviour.

Here we report a new in-plane solid-liquid-solid (IPSLS) mode for obtaining in-plane silicon nanowires (SiNW), which can be controlled and directly guided into various desired patterns for circuit architecture. Indium catalyst drops are firstly formed by a H2 plasma reduction of a thin layer of ITO on Corning glass substrate and then covered by an a-Si:H layer deposited at low temperature (100oC-200oC). The growth of SiNWs is activated in a reacting-gas-free thermal annealing process and led by the indium catalyst drops, that absorb and transform the a-Si:H matrix into crystalline SiNWs behind. At least two guided modes, that is, the a-Si:H channel guided mode and the step edge guided mode, can be applied to effectively control the growth routes for the lateral SiNWs. This guided growth of the IPSLS SiNWs lays an important basis for realizing various SiNWs-based device applications directly on top of low-cost substrates.

Microbial fuel cells (MFCs) use microorganisms to simultaneously break down organic materials and generate electricity. One of the greatest challenges in the practical application of MFCs is to sufficiently increase their power generation. Nanomodified graphite carbon anodes were prepared for use in MFCs to enhance the electron transport from the microbes to the electrode. Nanomodification to the anodes included growth of nanoparticles and multi-walled carbon nanotubes (MWCNTs). Nanoparticles of various metals, including Au, Ni, Pd, and Fe, were synthesized through thermal annealing and Fe catalyzed MWCNTs were synthesized through chemical vapor deposition. Power density was measured in MFCs for each type of nanomodified electrodes. Significant increase in power density was observed for the MFC with anodes decorated with MWCNTs (with 50-100nm diameters).

A versatile and non destructive technique for a chemical modification by grafting N-vinylcaprolactam (VCL) monomer on the polylactic (PLA) film surface is described. The film substrate is treated with a VCL solution, hexane and benzophenone (BP), the latest promotes the photo initiation. Grafting percentage is derived by a gravimetric method and the success in grafting is evaluated by contact angle technique, UV and ATR-FTIR analysis. The influence of the photoinitiator concentration is evaluated by the polymerization rate (Cp), grafting percentage (Cg) and grafting efficiency (Eg). The modified surface shows higher level of humectation or hydrophilicity, confirming successful surface functionalization of the polylactic acid film.