We have utilized wet-chemical etching of ellipsoidal silica nanoparticles to form silica nanoshells of a range of elliptical morphologies. The thicknesses of the silica ellipsoidal nanoshells are controlled through variation of synthesis conditions. A mechanism has been proposed to explain how the nanoshells are formed, and we have demonstrated that the porosity of the silica ellipsoid plays a role in the dissolution-regrowth process. We have also, via appropriate functionalization of the silica surface, coated the ellipsoidal nanoshells with Au nanoparticles.

The present work presents the synthesis, characterization and evaluation of the biocompatibility and ability to dissolve and chemically protect the anticancer drug doxorubicin (DOXO) of two polyethylene oxide-polystyrene oxide triblock copolymers, EO33SO13EO33 and EO38SO10EO38, where EO and SO denote the ethylene oxide and styrene oxide blocks, respectively. Block copolymer length and SO/EO ratio were selected with the objective of ensuring an optimal compromise between chain solubility, micelle formation ability and core size for enhanced drug solubilization. The temporal stability of the drug-loaded micelles and drug release profile were also analyzed as well as their efficacy as an antitumoral polymeric formulation in vitro by using a multidrug resistant ovarian tumor cell line (NCI-ADR-RES), with the special aim of analyzing the possible capability of both copolymers as potential P-glycoprotein efflux (P-gp) pump inhibitors to enhance DOXO accumulation in this cell line.

A hypothesis that probability giving Δ(1/V set) [= 1/V set (n) - 1/V set (n+1)] > 0, P[Δ(1/V set) > 0], increases with increasing the number of filaments contained in one memory cell, Nfila, and decreases with increasing switching cycle, n, was made to validate a multi-filament model (MFM) as a mechanism causing the cycle to cycle dispersion of V set in ReRAM. Here, Δ(1/V set) is the difference between the inverse of set voltages after n-th and (n+1)-th reset processes. This in turn means that V set will decrease with increasing Nfila and will increase with increasing n. In addition, another hypothesis that probability giving Δ(1/R) [= 1/R n - 1/R n+1] > 0, P[Δ(1/R) > 0], agrees with P[Δ(1/V set) > 0] was made by incorporating the assumption that v set depends on d with the MFM. Here, R n, v set, and d represent resistance in high resistance state after the n-th reset process, the set voltage of each filament, and the thickness of a gap between the electrode and the edge of the filament. The validity of these two hypotheses were confirmed by measuring the dependence of P[Δ(1/V set) > 0], P[Δ(1/R) > 0], and the mean value of V set, <V set>, on both the length of the perimeter, L, and n of Pt/NiO/Pt structures to which filaments were introduced by etching the NiO layer.

Enhanced near band-edge (NBE) emission was observed from composite structures fabricated from a PVA coated ZnO (PVA-ZnO) nanoparticle thin film embedded with multi-walled carbon nanotubes (MWCNTs). The enhancement is attributed to the resonant coupling between the bandgap transition of the semiconductor and the surface plasmon (SP) of MWCNTs. Moreover, the PVA-ZnO/MWCNTs/PVA-ZnO composite structures show faster transient response, which is due to the carrier transportation process in the composite structure. Reductions are observed for both photocurrent to dark current ratio and intensity of photoresponsivity, demonstrating a tradeoff between the time transient response and the detectivity.

P-type hydrogenated nanocrystalline cubic silicon carbide is a promising material for the emitter of n-type crystalline silicon heterojunction solar cell due to its lower light absorption and wider bandgap of 2.2 eV. The electrical properties of hydrogenated nanocrystalline cubic silicon carbide can be influenced by its crystallinity. In this study, we propose the use of conductive atomic force microscopy (Conductive-AFM) to evaluate the crystalline volume fraction (f c) of p-nc-3C-SiC:H thin films (20∼30 nm) as a new method instead of Raman scattering spectroscopy, X-ray diffraction, and spectroscopic ellipsometry.

In order to understand the structure property relationships for inorganic low dielectric constant (i.e. low-k) materials, transmission Fourier Transform-Infrared (FTIR) spectroscopy has been utilized to study the local bonding structure in various plasma enhanced chemically vapor deposited low-k materials in the SiOxCy:H phase diagram. The FTIR measurements were combined with additional mechanical, electrical, and optical property measurements to elucidate the structure property relationships for these materials. The combined measurements show that increased incorporation of terminal methyl bonding results in a decrease in network bonding that manifests itself in a reduction in mass density, dielectric constant, refractive index, Young’s modulus and many other important material properties.

In this work, it was used a Johnson-Cook elastic-plastic model to represent the behavior in the friction welding process of 6063 aluminum. Temperature and strain rate dependent laws were used to determine the behavior of the material. The results determined that the amount of heat transferred into the material dictates the quality and the microstructure of the welding and the mechanical strength of the welded joint in an ideal process.

In this paper, low-cost rectifier based on an organic diode for use in organic radio frequency identification (RFID) tags is proposed. Pentacene is the electroactive layer, with 7,7,8,8-tetracyanoquinodimethane (TCNQ) modified low-cost copper (Cu) and aluminum (Al) as the Ohmic and Schottky contacts, respectively. Hole injection barrier between Cu and pentacene can be decreased by forming the self-assembled layers of Cu-TCNQ. The diode shows a high rectification ratio of approximately 2×106 at 5V and the organic diode based rectifier circuit generated a dc output voltage of approximately 2V at 13.56MHz, using an input ac signal with zero-to-peak voltage amplitude of 5 V. The results indicate that chemical modification of the low-cost electrodes could be an efficient way toward low-cost high performance organic electronics devices.

With multifunctionality and nanoscale dimensions, self-assembled rosette nanotubes (RNTs) exhibit unique biological and mechanical properties, making them promising to serve as a new generation of implants. Synthetic twin G^C base features the hydrogen bonding arrays of both guanine and cytosine and has the ability to self-organize spontaneously into nanotubes with a 3.5 nm outer diameter, a 1.1 nm inner channel running the length of the nanotube which can reach several micrometers in length. In this study, a twin G^C motif functionalized with an aminobutyl side chain (referred to as TBL) was synthesized, assembled into bioactive RNTs and used along with poly(2-hydroxyethyl methacrylate) (pHEMA) and hydroxyapatite (HA) nanoparticles to prepare RNTs/HA/pHEMA composites for orthopedic applications. The properties of these composites was investigated, notably the solidification process, surface morphology, mechanical properties, and cytocompatibility properties. The RNTs assembled from TBL and HA nanoparticles were found to be effective towards increasing the bioactivity of the composites thus establishing the potential of TBL/HA/pHEMA composites as very promising injectable orthopedic implant materials.

Atomic layer deposition (ALD) was used to coat cellulose nanocrystal (CNC) aerogel scaffolds with a thin conformal layer of Al2O3. Electron probe microanalysis indicates that the penetration of Al2O3 into the aerogel was greater than 50 μm. Thermogravimetric analysis (TGA) shows that Al2O3 coated CNC aerogel composites have improved temperature and oxidation resistance.

Dendrons with a porphyrin core and π-conjugated dendron branches have been synthesized and characterized. The dendrons showed an all trans configuration. Cubic non-linear optical behavior of the styryl and porphyrin-containing dendrimers was tested viaZ-Scan measurements in spin-coated film samples.

If graphene is to be incorporated into transistors, solar cells, and capacitors, a large-scale synthesis of graphene must be devised. This research developed an innovative, simple, and cost-efficient synthesis procedure, dispersing graphene oxide in an ethanol-water solvent and reducing slowly with sodium borohydride (NaBH4). Reducing graphene oxide in 75:25 and 50:50 H2O:ethanol solutions with 15 mmolar NaBH4 produced numerous single-layered reduced graphene oxide sheets >1 μm2, and sometimes even >2 μm2. The quality of these sheets was confirmed by Raman spectroscopy, XRD, TGA, TEM, ED, and HRTEM.

Nonpolar a-plane InN/GaN heterostructures were grown by plasma assisted molecular beam epitaxy. The growth of nonpolar a- plane InN / GaN heterostructures were confirmed by high resolution x-ray diffraction study. Reflection high energy electron diffraction patterns show the reasonably smooth surface of a-plane GaN and island-like growth for nonpolar a-plane InN film, which is further confirmed by scanning electron micrographs. An absorption edge in the optical spectra has the energy of 0.74 eV, showing blueshifts from the fundamental band gap of 0.7 eV. The rectifying behavior of the I-V curve indicates the existence of Schottky barrier at the InN and GaN interface. The Schottky barrier height (φb ) and the ideality factor (η) for the InN/GaN heterostructures found to be 0.58 eV and 2.05 respectively.

We present a facile approach for growing radially oriented and dense ZnO nanorods and nanoneedles on the commercially available nylon fabrics by a simple, two-step wet chemical route. The samples were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), UV-Vis transmission spectroscopy, and wettability measurements. It was observed that the morphology of the resulting ZnO nanostructures strongly depended on the hydrothermal growth conditions. Excellent UV blocking activities were observed for ZnO nanorods containing nylon textiles in the wavelength region of 280-400 nm. Superhydrophobicity was achieved, for both ZnO nanorods and nanoneedles treated nylon fabric, upon 10mM 1-dodecanethiol treatment. ZnO nanostructures were durably attached to the nylon fabric after stirring 2 h in deionized water.

Like broken bones are able to heal themselves, it would be desirable that damaged concrete may be repaired autonomously as high costs are related to the repair. Actually, concrete already has some self-healing properties; when cracks appear, water enters and reacts with unhydrated cement grains which results in crack healing. However, only small cracks can be healed in this way. Therefore, we want to improve the self-healing efficiency by adapting the concrete matrix. By introducing high amounts of fibers several small cracks appear instead of one large crack. Combination with superabsorbent polymers, also called hydrogels, provides immediate crack sealing. Another methodology is to embed encapsulated polymeric agents in the matrix. When cracks appear, the capsules break and the agent is released. Upon contact of both components, they react and the crack is healed. This technique is also combined with CaCO3 precipitation of bacteria. In that case, not only polymers but also bacteria and nutrients are encapsulated and released upon cracking. First the polymer reacts, later the bacteria start to convert the nutrients into CaCO3 crystals which make the polymer structure denser and thus seal the cracks completely. As crack healing by means of bacteria uses a repair material which is more compatible with concrete we also try to seal cracks by only using bacterial CaCO3. Therefore, bacteria are embedded inside aggregates. Upon cracking, bacteria are exposed to the air and when water enters the crack bacteria become active and fill the crack with CaCO3. From the first results it was noticed that due to autonomous crack healing, water permeability is reduced and regain in mechanical properties is obtained. This means that more durable concrete structures may be obtained by using the proposed self-healing techniques.

Ceramics of alumina of high density and purity can have a broad application area due to the combination of the excellent properties such as resistance to corrosion, good biocompatibility, and high resistance to wear and moderate mechanical resistance. But its low fracture toughness limits its range of applications. One possibility of improvement in the properties of these materials might be in the use of nanometric inclusions of ZrO2 into the matrix of Al2O3. The aim of this paper was to obtain and characterize the nanocomposites of alumina containing 0, 5, 10, 15 and 30 vol% of nanometric zirconium, seeking improvements in the mechanical properties and its comparison with values found for the matrix without the inclusion. For that, nanometric particles of ZrO2 were added into the matrix of alumina in the different proportions, using mixture of suspensions. The samples of alumina and nanocomposites of alumina-zirconium were physically, microstructurally and mechanically characterized. The results obtained, showed the efficiency of the used process, obtaining a good dispersion of the particles of zirconium in the matrix of alumina. The adding of up to 15vol% nanometric zirconium in the matrix of alumina promoted an increase in the values of the mechanical properties when compared with alumina. For the nanocomposites containing 30vol%, a good dispersion of the zirconium inclusions did not happen, leading to inferior values in the measured properties.

It has been demonstrated in literature that chemical liquid deposition (CLD) processes such as dip coating, spray coating, roll coating, spin coating, curtain coating, meniscus coating etc. can be successfully used to deposit anti-reflective coatings on glass substrates. In comparison to physical vapor deposition (PVD), a CLD process generally is cost efficient because of lower capital requirements to set up coating manufacturing lines. Within the realm of CLD processes only some application techniques are suitable for high speed continuous manufacturing processes to deposit coatings on large area glass substrates. Significant differences in transfer efficiencies of these high speed application processes are readily apparent when material utilization per unit area of glass are compared. Roll coat process among all the high speed CLD processes stands out for its high material transfer efficiency due to direct contact printing on flat glass substrates. Honeywell Electronic Materials expanded its line of SOLARC® anti-reflective coating materials to include a new coating formulation SOLARC® RPV, which is customized for roll coating application. This paper highlights the advantages of using SOLARC® RPV in roll coat process and the performance attributes of SOLARC® anti-reflective coatings. Durability characteristics of these anti-reflective coatings in accelerated aging tests designed to simulate harsh field conditions will also be discussed.

Semiconductor nanowires (NWs) are fundamental structures for nanoscale devices. The excitation of NWs with laser beams results in thermal effects that can substantially change the spectral shape of the spectroscopic data. In particular, the interpretation of the Raman spectrum is greatly influenced by excitation induced temperature. A study of the interaction of the NWs with the excitation laser beam is essential to interpret the spectra. We present herein a finite element analysis of the interaction between the laser beam and the NWs. The resultas are applied to the interpretation of the Raman spectrum of bundles of NWs.

The information about concentrations of natural radionuclides in concrete mix and mineral raw materials used for concrete manufacture, supplementary cementitious materials (SCM) including, can be helpful for determination of concrete composition. The paper deals with the novel approach to determine concrete mix composition – using gamma-ray spectrometry.

In order to determine concrete composition, the content of naturally occurring radioactive materials (NORM) was determined in cement, FA and aggregates. Concrete compositions of both fresh and hardened mixes were determined by solving an over-determined system of four algebraic equations. The over-determined system consists of three equations, which represent activity concentrations of 226Ra, 232Th and 40K in concrete mix as a function of activity concentrations of the same radionuclides in cement, fly ash and aggregates, and the fourth conditional equation representing a sum of volumetric concentrations of cement, fly ash, aggregates and water in concrete mix as 100%. An over-determined system of linear equations was solved by the method of Lagrange multipliers, which provides a strategy for finding the maxima and minima of a function subject to constraints.

Gamma spectrometry was found very sensitive to the presence of FA in both fresh and hardened concrete, while 232Th activity concentration - well correlated with the FA content in the mixes. On the contrary, accurate determination of the rest of concrete composition was difficult.

We report a significant improvement in the electrical properties of CaCu3Ti4O12 (CCTO) dielectrics by the BaTiO3 (BTO) additive. The addition of BTO to CCTO was performed using two different methods of a solid-state mixing and a sol-gel coating. Compared with pure CCTO ceramics (ε r ∼ 52,000 and tanδ ∼ 0.38 at 100 kHz), BTO-added CCTO samples commonly showed a large improvement in the dielectric loss property although their dielectric constants were depressed around one order of magnitude; ε r ∼ 5900 and tanδ ∼0.05 for 5 mol% BTO-coated CCTO sample and ε r ∼ 4,075 and tanδ ∼ 0.02 for 5 mol% BTO-mixed CCTO sample. In addition, BTO-coated CCTO samples showed relatively lower leakage current than those of BTO-mixed CCTO samples, implying that the sol-gel coating is more effective for improving the electrical properties of CCTO.