It has been systematically investigated about the magnetic properties of the composite and single-phase SrFe12O19 prepared with the precursor of different Fe3+/Sr2+ molar ratios of 12:1, 11:1 and 10:1, respectively. With increasing the calcinations temperature, the coercivity of all samples decreases which can be determined by the stress model. The δm(H) results indicate that the intergrain exchangecoupling interaction exists both in composite and in single-phase SrFe12O19, resulting in the remanence magnetization enhancement, and the magnetostatic interaction become dominant in the samples with higher calcinations temperatures. The irreversible susceptibilities χirr(H) curves show that there may exhibit the exchange-spring behavior in the composite SrFe12O19 with more soft magnetic γ-Fe2O3, and the irreversible switching field may be qualitatively used to determine the coercivity magnitude.

X-ray diffraction (XRD) patterns indicated that the powder of 4-tricyanovinyl-N,Ndiethylaniline (TCVA) has a polycrystalline structure with triclinic crystal system. The scanning electron microscope of the as deposited TCVA thin film shows a nanocrystalline structure with crystallite size of 45–75 nm. The crystallite size increases by increasing film thickness and annealing temperatures. The dark electrical resistivity decreases with increasing film thickness. Such variations are a consequence of crystallite size effect on the electrical resistivity of the films. The conductivity of the films measured in air is high in comparison to those measured under vacuum by one order. The removal of the hydroxyl group states by evacuation decreased the electrical conductivity of TCVA films. The temperature dependence of the electrical conductivity of TCVA films shows that the conduction is through a thermally activated process having two conduction mechanisms. The average values of activation energies are 0.28 and 0.74 eV for extrinsic and intrinsic conduction mechanisms, respectively. H-O group adsorption is responsible for the extrinsic conduction in TCVA films.

In this work we present a theoretical and mathematical relationship which calculates the site reaction probability (SRP) of the sticking on (Si-) dangling bonds (DB) or the SRP to abstract H from (Si-H) bonds, on the a-Si:H surface. The results are in agreement with those obtained by the Monte Carlo simulation. Using these probabilities allowed us to compute the surface reaction probability of SiHx radicals on a-Si:H for several values of the temperature. The surface reaction probability (SFRP) results show also an excellent agreement with other works found in the literature.

In the present work, ZnO and ZnO:Cu thin films with c-axis preferred orientation were prepared on porous silicon, silicon and glass substrates by radio frequency magnetron sputtering technique. X-ray diffraction measurements revealed that the particle size of all samples was in the range of 11.41 ~ 17.67 nm. All the samples exhibited a compressive stress. Fourier transform infrared spectroscopy showed the presence of Si-O-Si stretching appeared at 1067 cm–1, which was assigned to the transverse optical mode of the asymmetric vibration. The E2 (high) mode indicated that the residual stress was observed in the Raman spectra. The optical transmission and absorption spectra were studied, indicating that the optical band gap value shifted to a longer wavelength after Cu doping. Effect of substrate material and Cu doping on the photoluminescence properties of ZnO thin films, along with the origin of some emission peaks, was discussed in detail. The experiment results indicate that the ZnO and ZnO:Cu thin films grown directly on the Si substrates have a high quality of crystallization and intense blue luminescent properties.

We present in this work a contribution to the study of the solid solution (1 – y)BiFeO3/y(Ba0.7Na0.3Ti0.7Nb0.3)O3. Room temperature X-ray diffraction patterns for some prepared compositions confirmed the formation of perovskite structure. The study of the evolution of dielectric properties as a function of sintering temperature allowed us to determine the optimum conditions that minimize the presence of defects and oxygen stoichiometric limit fluctuations due to the volatility of bismuth. The variation of permittivity as a function of temperature and frequency for the (1 – y)BiFeO3/y(Ba0.7Na0.3Ti0.7Nb0.3)O3 solid solution was measured. The effect of Ba0.7Na0.3Ti0.7Nb0.3O3 addition content on crystal structure, dielectric and magnetic properties of BiFeO3 was investigated. Raman measurements reveal resonant enhancement of two-phonon excitation for (1 – y)BiFeO3/y(Ba0.7Na0.3Ti0.7Nb0.3)O3 samples. We also expect that the solid solution shows weak ferromagnetic behavior for low Ba0.7Na0.3Ti0.7Nb0.3O3 levels of substitution.

The possibilities for extracting chemical composition-related information from a singlewavelength X-ray reflectometry experiment are investigated. It is shown that the X-ray absorption of certain elements is sufficient to cause a significant effect on the reflectivity curve, which can be in turn exploited to determine its abundance in the thin film. The limitations are discussed using simulated data and the methodology is applied for the determination of the iodine concentration in iodine-treated thin polyaniline films. More generally the method appears to be very sensitive for the non-destructive determination of the weight percentage of metal nanoparticles in thin polymer films.

A series of CuxMg1–xNb2O6 (x = 0, 0.2, 0.4, 0.6, 0.8, 1) columbites were prepared using the sol-gel technique. The samples were sintered at 900 °C for 6 h. The prepared samples were structurally characterized using X-ray diffraction (XRD) method. To study their applicability in low temperature cofired ceramic (LTCC) technology, elastic properties have been characterized for mechanical compatibility. Elastic behavior was investigated at 300K, employing ultrasonic pulse-transmission technique at 1 MHz. The values of elastic moduli and acoustic Debye temperature (µD) were computed from longitudinal and shear velocities. The measured values were corrected to zero porosity using Hasselman and Fulrath's formula. The elastic constants of the samples, estimated using Modi's heterogeneous metal-mixture rule, were also reported. The variation of elastic moduli was interpreted in terms of strength of interatomic bonding. Microstructure of these samples was studied using the FESEM (field emission scanning electron microscopy) technique. Mechanical properties including yield strength, tensile strength and thermal stress resistance were calculated from thermal properties measured through thermal conductivity and thermal expansion coefficient.

ZnO nanocrystals doped with Fe2O3 have been synthesized by the calcination method. Ferromagnetic resonance (FMR) study of 0.3(Fe2O3/0.7(ZnO) nanocomposite has been carried out in the 4–300 K range. The presence of magnetic zinc ferrite ZnFe2O4 nanoparticles with an average crystallite size of 11 nm was identified by XRD. Temperature dependence of the resonance field, linewidth and the integrate intensity calculated from FMR spectra has been determined. Existence of two temperature regimes: high (above 50 K) and low (below 50 K) has been established, further divided into two temperature ranges. The results of FMR study of agglomerated ZnFe2O4 nanoparticles indicate an important role of magnetic interactions, both inter-particle (exchange and dipolar) and intra-particle connected with the core-shell magnetic structure.

In this study, the effect of Nd2O3 nano-islands on the critical properties of NdBa2Cu3O7–δ (Nd-123) superconductive thin films grown on Ni-W metallic substrates was investigated. Nd-123 superconducting ceramic materials were prepared by solid-state reaction technique and then this ceramic material was used as target for producing the Nd-123 superconductive thin films with pulsed laser deposition (PLD). Nano-islands were prepared with the deposition of Nd2O3 by PLD. The obtained superconductive thin films were characterized by X-ray diffraction (XRD) analysis, morphological investigations of atomic force microscopy (AFM) images, transport analysis such as Jc and R-T measurements by four-point probe (FPP). As a result of these analyses, it was determined that nano-islands have important role for the flux pinning and it provides the increase of about 32% for the critical current value (Jc).

Polyethylene glycol (PEG) and mercaptoethanol (ME)-capped CdSe nanoparticles (NPs) have been successfully prepared and systematic investigation on structural, optical and photocatalytic properties is presented. The intrinsic characteristics of resulting nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible and photoluminescence (PL) spectrophotometer. Cubic phase, nearly uniform size (∼10 nm) and spherical morphology of the synthesized nanoparticles were established through XRD and TEM analysis. Spectroscopic measurements exhibit that capping agent can effectively tune energy band structure. ME-capped CdSe NPs exhibit higher light emission efficiency as compared to PEG capping. Photocatalytic activity of CdSe nanoparticles on methylene blue (MB) dye, a significant enhancement was observed in the photodegradation efficiency. A maximum degradation of MB dye (73.5%) was obtained.

The crystallographic microstructure properties of Al-Ti alloys rapidly solidified by a vacuum melting process were investigated by XRD, SEM, optical observations and DSC analysis. It was found that the microstructures are polycrystalline fine-grained (typically 10—20 µm) of intermetallics in equilibrium with the solid solution Fcc α-Al(Ti) matrix.

Characteristics of the parametric γ-radiation (PGR) from relativistic electrons in Mössbauer crystals are analyzed in the framework of the kinematical diffraction theory taking into account the interference between electron and nuclear resonant parts of the crystal X-ray polarizability. Optimization of crystal parameters, electron energy and diffraction geometry is carried out in order to increase the brightness of the resonant γ-radiation source based on PGR. A possible experimental setup for observation of PGR is discussed.

In this study, the properties of polypropylene fabrics grafted with chitosan after being activated by low temperature plasmas were evaluated. The chitosan was applied to polypropylene fabrics by using pad-dry cure technique. The surface morphology was characterized by SEM images. Treated samples were characterized by means of Fourier transform infrared (FTIR) spectroscopy. The polypropylene fabric treated with chitosan demonstrates an excellent dyeability property.

Plasma-immersion ion implantation (PIII) is a potent method to obtain hard and wear-resistant surface on Ti by nitrogen implantation. This presentation is one part of a sequence of experiments to optimize the microstructure and physical properties of TiN through adapting the plasma-processing parameters. In this work, nitrogen ions were implanted into samples of pure Ti at different nitrogen pulse frequency without using any external source of heating. The nitrogen-implanted surfaces were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES), optical microscope, nano-indentation technique, ball-on-disk type tribometer, surface profilemeter, Tafel polarization technique for corrosion performance and ellipsometry. The outcomes show that, nitrogen PIII is an effectual method for nitriding titanium and nitrogen pulse frequency affected the microstructure and physical properties of the treated Ti. X-ray diffraction depicted the formation of α-Ti (N) and the cubic TiN after implanting titanium by nitrogen and the thickness of the nitrided layer increased as the nitrogen pulse frequency increased. The wear and corrosion resistance of the nitrogen-implanted titanium are improved and the friction coefficient decreased from nearly 0.8 for the un-implanted titanium to 0.3 for the implanted titanium, this ascribed to the formation of the titanium nitrided phases. Ellipsometric measurements were carried out on the PIII titanium samples at different nitrogen pulse frequency. The ellipsometric measurements show that, the thickness of the nitrided layer and surface roughness increased while the refractive index decreased with increasing nitrogen pulse frequency.

Photonic crystal (PC) waveguide is one class of PC devices that has been demonstrated for RI measurements. In this paper, we have reported a new design of infiltrated optofluidic sensors based on 2D photonic crystal slab with triangular lattice pattern of ring-shaped holes. The properties of the sensor are simulated using the finite-difference time-domain (FDTD) method. The transmission spectra have been measured by changing the refractive index of holes and it has been found that with increasing refractive index, wavelength position of transmission spectrum shifts. The radius and the shape of the air holes localized at each side of the line defect are optimized to realize high sensitivity, wide measurement range and improved transmission. An improved optofluidic sensor design is also described and a 210 nm wavelength position of upper band edge shift was observed corresponding to a sensitivity of more than 636 nm per refractive index unit (RIU).

In this paper, we investigate the different parameters that affect the distribution of the transmembrane potential of cells brought into contact before electrofusion in a miniaturized fluidic device. In particular, we discuss the deviation of the effective transmembrane voltage compared to the one predicted by Schwan’s law. The application of electric field pulses to biological cells induces a transmembrane potential which leads to cell permeabilization. Electrofusion occurs when several cells are brought into contact while they are electropermeabilized. Nevertheless, we show that in this case, the mutual presence of cells interferes on Schwan’s equation. Consequently, the transmembrane voltage at the cell contacting point is drastically reduced, which is not favorable for an electrofusion in smooth conditions, as the applied voltage needs to be increased to compensate this phenomenon. We show that the introduction of polymer obstacles reverses this trend, as the high electric field region is focused on the fusion zone. To confirm the theory we developed, quantitative biological experiments are presented in which murine melanoma cells were paired and fused in both conditions (with and without obstacles).

Since the pioneer work by Bender and Boettcher on non-Hermitian Hamiltonian under paritytime (PT) symmetry [Phys. Rev. Lett. 80, 5243 (1998)], PT-symmetry optical coupled systems have been investigated extensively. Here we propose theoretically perfect transparency of a PT-symmetric acoustic coupled system which is comprised of a waveguide channel and two same-sized side-coupled resonators. Specifically, we demonstrate that with the change in the amplitude of attenuation and amplification coefficient, the spatial symmetry of two resonators is spontaneously broken which triggers an acoustic analog of electromagnetically induced transparency (EIT) by assigning anti-phase to the pressure field inside the two resonators.

The possibility to do surface measurements on sample containing151Eu by detection of Auger electrons delivered in the decay process of the Mössbauer nucleus is briefly presented herein. The test measurements have been carried out on Eu2O3 powder sample. A higher resonance effect and a lower line width have been obtained in backscattering geometry compared with transmission geometry.