Using molecular dynamics simulations, we have investigated the effect of embedding nanoclusters of radius 3-7 Å on the dynamical and mechanical properties of 1,4-cispolybutadiene melts. To see the effect of polymer-nanocluster interaction strength on the bulk modulus, the van der Waals interactions (vdW) between the polymer chain and nanocluster have been varied from weak to very stong while keeping polymer-polymer and nanoclusternanocluster interactions constant. The modulus depends on the interaction strength, but not on nanocluster size. Residence time of chains on the surface of the nanocluster (τr) has an increasing trend that reaches to a plateau as the vdW strength is increased. τr also doubles from 100 ps to 200 ps as the nanocluster size is increased from 3 to 7 Å. Our findings give clues on how the properties of polymeric materials may be controlled by nanoparticles of different chemistry and size.

Short channel organic thin film transistors in bottom-gate, bottom contact configuration use typically gold metallization for the source and drain contacts because this metal can easily be cleaned from photoresist residuals by oxygen plasma or ultraviolet-ozone and allows also surface modification by self-assembled monolayers (e.g. thiols). Alternative low-cost bottom contact metallization for high performance short-channel organic thin film transistors are scarce because of the incompatibility of the bottom contact material with the cleaning step. In this work a new process flow, involving a temporary thin aluminum protection layer, is presented. Short channel (3.4 μm) pentacene transistors with lithographical defined and thiol modified silver source/drain bottom contacts (25 nm thick, on a 2 nm titanium adhesion layer) prepared according to this process achieved a saturation mobility of 0.316 cm2/(V.s), and this at a metal cost below 1% of the standard 30 nm thick gold metallization.

In-situ micro Raman spectroscopy has been adopted as one of the most powerful analytical techniques with high spacial resolution under controlled atmospheres. In the present study, phase transformation of NiO doped yttria stabilized zirconia (YSZ) was monitored by in-situ micro-Raman spectroscopy. Raman spectra change caused by the phase transformation from the cubic phase to the tetragonal phase was observed for the NiO doped YSZ during annealing at a high temperature of 1173 K under reducing atmosphere.

Gelatin was functionalized with glycidyl methacrylate and photocrosslinked in the presence of poly(ethylene glycol) dimethacrylate (PEGDMA) or poly(ethylene glycol) monomethacrylate (PEGMA) to create a biopolymer-based system with tailorable properties. These co-networks were hydrolyzed using 6 M HCl and the degradation products were analyzed and identified using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. This technique successfully identified gelatin-derived peptides such as FLPEPPE, SFLPEPPE, and SFLPEPPEE as well as an accompanying PEG-g-poly(methacrylic acid) component. No oligo- or polymethacrylates were monitored at any molecular weight range above m/z = 500, which indicated that they possessed lower molecular weights. An in vitro hydrolytic degradation experiment performed in pH 7.4 PBS buffer solution at 37 °C showed that these networks, which were prepared without the addition of a potentially toxic photoinitiator, exhibited mass loss of up to 50 wt% at 6 weeks of incubation time. These results provide valuable insight into how these functional gelatin-based co-network biomaterials will perform in a biological setting.

UV exposure of dye-sensitized solar cells (DSCs) results in a loss of triiodide from the electrolyte and this is as a result of direct band gap excitation of the TiO2 semiconductor. The UV stability of a typical electrolyte composition is explored further and the results show that the electrolyte is very stable to UV irradiation in the absence of TiO2 but experiences rapid triiodide loss in its presence. Furthermore, the effect of a periodic triiodide regeneration technique, applied to UV exposed DSCs, is investigated and whilst this treatment does not appear to be able to permanently reverse triiodide loss in UV exposed cells, devices that are periodically regenerated, maintain higher average photocurrents over the UV exposure period.

In the present work an alternative nanoparticle synthesis technique was developed, where the nanoparticles nucleate and grow inside the pores of the nanostructured porous silicon (NPS). Employing green method for the nanoparticle synthesis, yeast extract is used as a reducing agent. The porous layers were prepared by electrochemical etching of Boron-doped (100) Si substrate (0.01-0.02Ohm·cm). The NPS support was immersed into the reactive colloid for different times, then withdrawn, cleaned and dried. SEM and XRD measurements were carried out to characterize the NPS substrate and the immobilized catalyst nanoparticles. EDX mapping shows a homogeneous deposition of nanoparticles on the porous support. The average particle size, calculated from XRD diffractograms (using the Scherrer`s formula), was found between 6 to 10 nm. This method provides a good incorporation and distribution of nanoparticles, also an alternative environment-friendly technique to develop catalytic devices fabricated on silicon substrate with an additional advantage of being integrated with the silicon based microelectronic circuits.

Platinum/Cerium oxide-based catalysts for methanol electro oxidation were prepared by the occlusion deposition technique. Composite glassy carbon (GC) electrodes were modified and then tested towards the methanol electro oxidation half reaction in acid and alkaline medium. Cyclic voltammetry and chronoamperometry techniques were used to test the catalytic response of the composite electrodes. AFM studies were carried out in order to have a measurement of the particle size and distribution of the platinum/ceria catalyst on HOPG.

Membranes with dimensions up to 10 mm x 15 mm have been fabricated in epitaxial 3C-SiC/Si wafers. An array of CTLM metal contacts was deposited onto the upper surface of the n-SiC membrane. Both Al/n-SiC and Pd/n-SiC contacts which were formed on the membrane and on the adjacent substrate have shown an ohmic current/ voltage response. Values of specific contact resistance, ρc, were measured directly on the membranes. These results have shown no consistent difference in ρc of the contacts located either on the membrane or off the membrane. The exposure of SiC surfaces to reactive ion etching in CF4 plasma during the fabrication of a membrane has resulted in ρc which was higher by a factor of 103 than with as-grown and KOH etched silicon surfaces.

We discuss how to use Wang-Landau simulations in an efficient manner to investigate the statistical mechanics of individual lattice polymers and peptides adsorbed at a planar surface. For nearest neighbor interactions, we show that a single Wang-Landau simulation, recording the density of states as a function of numbers of internal contacts and of surface beads, is sufficient to give a full description of the phase behavior of both adsorbed and desorbed states of single molecules. It is not necessary to introduce a second confining wall. Moreover, moves are never rejected due to overlap with the surface.

The proposed “wall-free” method has already been applied to homo-polymers and hetero-polymers (lattice peptides using the HP model) on a uniform surface, and on regularly patterned surfaces. We give here a specific example to indicate how the relative adsorption strengths of a given peptide on different surfaces may be calculated.

Fluorine substitution in CaH2 has been studied by means of experimental and theoretical methods. Samples with various compositions have been prepared by ball milling. In situ X-ray diffraction analysis has been carried out as a function of temperature by synchrotron radiation experiments. An increase of mixing has been observed during heating, suggesting that mixing is thermodynamically favoured but it is kinetically hindered at low temperatures. Ab initio DFT calculations have been performed to estimate the thermodynamic mixing properties of both orthorhombic and cubic solid solutions. On the basis of ab initio results and literature information, a thermodynamic assessment within the CALPHAD framework has been performed and the pseudo binary CaH2-CaF2 phase diagram has been calculated. The formation of orthorhombic and cubic terminal solid solutions in the CaH2-CaF2 system is predicted, in good agreement with experimental findings.

Terahertz (THz) imaging technique has attracted much attention in recent years, because the technique can be applied to many application fields such as nondestructive analysis and imaging method through optically opaque materials. A THz real-time imaging equipment (Terahertz Camera) considered increasingly important in the future has been developed. We report a THz video rate imaging system consisting of a quantum-cascade laser (QCL) light source as a THz illuminator, and a Si-technology based un-cooled micro-bolometer focal-plane array (an infrared detector common in thermal cameras). We also describe two applications of our imaging system: stand-off imaging for search and rescue in a fire disaster, and label-free biomaterial detection.

Highly densely packed, self-organized silicon nanowires with very narrow diameter distribution were synthesized within porous anodic alumina templates with electrodeposited catalytic metal nanoparticles. For successful catalytic metal nanoparticle deposition, electrochemical-, and chemical barrier layer thinning process was investigated following anodization process. Controlled pulsed electrodeposition process was carried out for a volume calibration of desired catalytic metal nanoparticle deposition inside nanopore arrays using different metal-ion containing electrolyte. Not only single metal nanoparticles, but also multi metal nanoparticles layers were filled inside PAA to enhance metal filling aspect, and to control the volume of nanoparticles more precisely. Using multilayered metal nanoparticles resulted on different SiNW’s growth behavior depending on the types of underlying metal nanoparticles.

SiNWs were successfully synthesized using hot-filament assisted chemical vapor deposition system. Although silicon precursor gas can generally be dissociated at relatively low temperatures, the use of a hot filament activation help decreasing process temperature, and also, highly activated atomic hydrogen generation via the tungsten hot filament placed at gas inlet helps preventing parasitic amorphous silicon deposition on either the alumina membrane surface or the pore wall which hinders appropriate growth of SiNWs in PAA by nanopores clogging. Such densely packed, self-organized SiNWs are of high interest in many application fields like nanoelectronics, optoelectronics, and energy storage/conversion devices etc.

We review the progress in the electron tomography of dislocation microstructures in the transmission electron microscope (TEM). Dislocation contrast is visible both in conventional TEM and scanning TEM (STEM) modes and, despite the complicated intensity variations, dislocation contrast can be isolated using computational filtering techniques prior to reconstruction. We find that STEM annular dark-field (STEM-ADF) imaging offers significant advantages in terms of dislocation contrast and background artifacts. We present several examples, both in semiconducting and metallic systems, illustrating the properties of 3D dislocations. We present the high-angle triple-axis (HATA) specimen holder where the diffraction condition can be chosen at will and dislocation tomograms of multiple reflections can be combined. 3D dislocations are analyzed in terms of dislocation density and dislocation nodal structures. Several avenues of study are suggested that may exploit the 3D dislocation data.

Manufacturing of high dimension steel rings impose several technological challenges. The lack of understanding of the principles and practices of quenching can result in inadequate hardness, excessive distortion or scrapping of costly machined components. This paper presents the results of an analytical study of the parameters of the quenching operation, among them the fluid dynamics of the agitation in the quenching media. Velocity components of the fluid were measured using an anemometer inside the quenching tank. Uniformity of agitation is compared with a Computational Fluid Dynamics (CFD) simulation. The CFD results revealed the impact of quench tank design, configuration and operation of impellers.

CdTe and CdS are emerging as the most promising materials for thin film photovoltaics in the quest of the achievement of grid parity. The major challenge for the advancement of grid parity is the achievement of high quality at the same time as low fabrication cost. The present paper reports the results of the new deposition technique, Pulsed Plasma Deposition (PPD), for the growth of the CdTe layers on CdS/ZnO/quartz and quartz substrates. The PPD method allows to deposit at low temperature. The optical band gap of deposited layers is 1.50 eV, in perfect accord with the value reported in the literature for the crystalline cubic phase of the CdTe.

The films are highly crystalline with a predominant cubic phase, a random orientation of the grains of the film and have an extremely low surface roughness of 4.6±0.7 nm r.m.s.. The low roughness, compared to traditional thermal deposition methods (close space sublimation and vapour transport) permits the reduction of the active absorber and n-type semiconductor layers resulting in a dramatic reduction of material usage and the relative deposition issues like safety, deposition rate and ultimately cost

A nanofluid is a solid-liquid composite material consisting of a stable suspension of nanometric particles in a conventional refrigerant liquid expected to exhibit enhanced heat transfer properties. Elemental silver (Ag) was selected in this research because of its high electrical and thermal conductivity that are likely to be dependent on the crystal size and shape at the nanoscale. Accordingly, we have synthesized highly monodisperse silver nanowires and nanocrystals by reducing silver nitrate solutions with ethylene glycol in presence of polyvinylpyrrolidone, (PVP). The shape-control in the silver nanostructures was achieved by a proper selection of the type and level of chloride salts, e.g. KCl and CaCl2, and specific PVP/Ag mole ratios in starting solutions. The development of the metal phase was confirmed by X-ray diffractometry. Transmission electron microscopy analyses evidenced the formation of silver nanowires exhibiting a very uniform thickness that could be tuned in the 40-130nm range. UV-vis measurements evidenced the plasmon peak at ∼387nm and clear shoulders at ∼357nm that are indicative of the formation of elongated nanostructures.

The shape-memory properties of electrospun polyetherurethanes (PEU) non-wovens with a single fiber diameter of around 1 μm were explored. In uniaxial cyclic, thermomechanical tensile tests a dual-shape shape-memory creation procedure (SMCP) was applied and the shape recovery was examined under stress-free and constant strain conditions. The thermal properties of the electrospun PEU non-wovens were found to be similar to those obtained for bulk PEU samples, whereas the mechanical properties revealed differences with respect to the elongation at break (εb ) at increased temperatures. Excellent dual-shape properties were achieved for the PEU non-wovens with a high shape fixity rate (Rf ) and shape recovery rate (Rr ). A significant higher recovery stress (σmax ) was obtained under constant strain recovery conditions for the electrospun non-wovens compared to the bulk PEU samples, which might be attributed to the higher degree of orientation of the polymer chains in the microfibers. Therefore the influence of different (single) fiber diameters as well as the variation of the programming elongation εm and temperature Tprog on σmax is an interesting issue for future investigations.

This paper presents the data on sorption efficiency of nanodiamonds, detonation soot and its complexes with polyaniline for nano size biological objects: fragments of cDNA and epidemic influenza viruses, including A(H1N1, H3N2) and B strains, isolated in 1999-2010, pandemic strain A(H1N1)pdm09, influenza avian A(H5N2) viruses and reassortants A(H5N2) and A(H5N1). As the result of the sorption on detonation nanodiamonds (DND), detonation soot and their complexes with polyaniline, hemagglutination (HA) titers of virus solutions decreased by ≤ 4000 times for concentrated viruses, suspended in saline and by ≤8 times for allantoic viruses. The detonation soot was approximately 2.5 times more effective than DND. Detonation nanodiamond materials proved to be efficient sorbents for cDNA fragments of >190 bp size. No desorption of viruses from nanodiamonds and soot into saline was revealed (observation time 48 h). DND and soot at concentrations ≤ 1 mg/ml were not toxic for MDCK cells. A moderate increase of monocytes was registrated in blue rats after intra-abdominal immunization with DND+ virus complexes.

Bulk EuTiO3 is known as a compound in which spin and soft phonon mode is strongly coupled. Recent theoretical study suggests that application of stress or formation of strain leads to a drastic change in magnetic and dielectric properties of EuTiO3 and that so-called multiferroic properties emerge under such a situation. In the present study, effect of strain induced by a substrate, on which EuTiO3 thin film is deposited, on the magnetic properties of the film has been experimentally examined. By using a pulsed laser deposition method, EuTiO3 thin film has been deposited on different kinds of substrate, i.e., LaAlO3, SrTiO3, and DyScO3; the lattice parameter of these compounds is smaller than, just the same as, and larger than that of EuTiO3, respectively. X-ray diffraction analysis confirms that the strain induced in the plane of as-deposited EuTiO3 thin films on different substrates is coincident with the lattice parameter of the substrate compounds. Also, all the as-deposited EuTiO3 thin films manifest elongation of lattice in a direction perpendicular to the film surface. Temperature dependence of magnetization indicates that all the thin films exhibit ferromagnetic behavior at low temperatures. The magnetization at 2 K under a magnetic field of 100 Oe is the highest for EuTiO3 on DyScO3 and the lowest for EuTiO3 on LaAlO3. The experimental result is coincident with the first-principles calculations which predict that ferromagnetic spin configuration becomes more stable as the lattice volume of EuTiO3is increased.