Mustafa Okutan

Electrical properties of Zn-phthalocyanine and poly (3-hexylthiophene) doped nematic liquid crystal

An E7 coded nematic liquid crystal was doped with zinc phthalocyanine and poly (3-hexylthiophene). A variety of properties including relaxation time, absorption coefficient, and critical frequency of this doped system were investigated using impedance spectroscopy. The doped systems displayed increased absorption coefficients in the range 0.22-0.55 and relaxation times from 5.05 × 10-7 s to 3.59 × 10-6 s with a decrease in the critical frequency from 3.54MHz to 2.048 MHz.

Energy Absorption and Exposure Buildup Factors of Essential Amino Acids

The effective atomic number and effective electron density in amino acids are of significant interest due to their use in various applications. The energy absorption buildup factors, exposure buildup factors, effective atomic numbers, and electron densities of essential amino acids such as Leucine (C6H13NO2), Lysine (C6H14N2O2), Methionine (C5H11NO2S), Phenylalanine (C9H11NO2), Threonine (C4H9NO3), Tryptophan (C11H12N2O2), Valine (C5H11NO2), Arginine (C6H14N4O2), and Histidine (C6H9N3O2) were determined theoretically in the energy range 0.015–15 MeV.

Resistivity, ESR, and Radiation Shielding Properties of the Volcanic Rock Materials

Pumices have been used in cement, concrete, brick, and ceramic industries as an additive and aggregate material. It will be important to study pumice types by using a different tool as EPR which is a new technique for related material to be used for industrial aims. Electron spin resonance (ESR) spectra of the pumice types were taken by EMX-type spectrometer. Also, the current-voltage (I-V) and surface resistivity probe stand of the thin films was studied using a four-point probe measurements. The relationship between radiation shielding properties of the pumice samples and their surface resistivity, chemical, and electrokinetic properties was evaluated using simple regression analysis. Simple regression analysis indicated a strong correlation between surface resistivity and density and SiO2, Fe2O3, CaO, MgO, and TiO2 content of pumice samples in this study. It is found that a correlation between determined -factor by EPR spectroscopy and radiation shielding is established for pumice samples.

I-V characteristics of Pt x Co 1-x (x = 0.2, 0.5, and 0.7) thin films

Three different chemical ratios of PtxCo1-x thin films were grown on p-type native oxide Si (100) by Magneto Sputtering System with cosputtering technique at 350°C temperature to investigate electrical prosperities. X-ray photoelectron spectroscopy analysis technique was used to specify chemical ratios of these films. The current-voltage (I-V) measurements of metal-semiconductor (MS) Schottky diodes were carried out at roomtemperature. Fromthe I-V analysis of the samples, ideality factor (n), barrier height (φ), and contact resistance values were determined by using thermionic emission (TE) theory. Some important parameters such as barrier height, ideality factor, and serial resistance were calculated from the I-V characteristics based on thermionic emission mechanism. The ideality factors of the samples were notmuch greater than unity, and the serial resistances of the samples were also very low.

Photon Atomic Parameters of Nonessential Amino Acids for Radiotherapy and Diagnostics

The total mass attenuation coefficients (μ t) (cm2/g) and atomic, molecular, and electronic effective cross sections have been calculated for nonessential amino acids that contain H, C, N, and O such as tyrosine, aspartate, glutamine, alanine, asparagine, aspartic acid, cysteine, and glycine in the wide energy region 0.015–15 MeV. The variations with energy of total mass attenuation coefficients and atomic, molecular, and electronic cross sections are shown for all photon interactions.

Electrical Behavior of Probertite by Dielectric Spectroscopy

Abstract In this work of the material investigation, electrical parameters, which are real part and imaginary part of modulus, dielectric constant, dissipation factor, and conductivity, in the bulk pellet of probertite sample is presented. Electrical properties were investigated via temperature and frequency dependent dielectric spectroscopy. Real and imaginary part of dielectric parameter properties of the probertite were measured at frequencies from 100 to 15M Hz in the temperature range of 25 to 150 °C. Temperature dependence of the real part of the dielectric constant suggests that these compounds exhibit strong electromagnetic absorption and broadband electrical behavior.

Effect of borax additive on the dielectric response of polypyrrole

The main aim of this study is to produce added polypyrrole (PPy) borax composites with high dielectric properties for technological applications. For this purpose, PPy–borax composites with different borax concentrations varying from 10 to 50 wt% have been prepared. To reveal their structural and morphological attributes, the composites have been characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. The real and imaginary parts of complex dielectric function, the imaginary component of complex electrical modulus and ac conductivity have been investigated at room temperature as a function of frequency in the range 100 Hz–15 MHz. It has been found that addition of borax increases the dielectric constant of pure PPy. In this respect, PPy–borax composites with the highest dielectric constant at low frequency may be utilized in charge storing devices. On the other hand, the dielectric loss is also very high in low-frequency region for the composites with high borax content. Exploiting this property, the material may also be used in decoupling capacitor applications. The relaxation mechanisms of the samples have also been determined as non-Debye type. The Nyquist curves of the samples have been analysed for calculating the grain and grain boundary resistance and capacitance values. In conclusion, borax has a promising potential to be used as a cheap and effective filler for improving the dielectric properties of PPy polymer.

Molecular orientation of nickel phthalocyanine doped nematic liquid crystal composite under magnetic field

ABSTRACT The electrical and dielectric properties of the nematic liquid crystal (E63) and Nickel Phthalocyanine (NiPc) doped E63 composite have been investigated by dielectric spectroscopy under 0–0.4 T magnetic field. It has been observed that NiPc doping and external magnetic field, B decrease threshold voltage. Moreover, conductivity of the composite has an increasing tendency with magnetic field. Furthermore, a significant decrease in relaxation frequency with B has been interpreted as the simplification of molecular orientation. Hence, NiPc doping enhances the magnetic sensitivity of E63 and increases molecular orientation ability and conductivity.

The impact of NiPc additive and laser light dielectric properties of E63 nematic liquid crystal

ABSTRACT In this work, the electrical properties of the pure nematic liquid crystal (E63) and different concentrations Nickel Phthalocyanine (NiPc) doped (E63+1%NiPc, E63+3%NiPc and E63+5%NiPc) E63 have been investigated by means of dielectric spectroscopy measurements under laser light illumination. The variations of the real () and imaginary () parts of dielectric constant with frequency have been studied. According to versus voltage graphics, threshold voltage, Vth has been calculated. It has been observed that while NiPc doping increases the Vth, the application of laser light has a remarkable decreasing effect on threshold voltage, Vth. The absorption coefficients, , and relaxation times, , have also been calculated for determining the relaxation mechanism. It has been revealed that the relaxation type of these materials is nearly-Debye type regardless of the laser illumination. Moreover, the dielectric strength has been analysed both Debye and Cole-Cole models. Furthermore, conductivity mechanisms of these composites under dark and laser illumination have been investigated for four frequency regions. It has been shown that conductivity mechanism of the composites are not affected by application of laser light above .

Dielectric Properties of 4-Cyano-4′-pentylbiphenyl (5CB): 4-[4-(S)-2-Methylbutoxybenzoyloxy]benzoic Acid (BAC) Composite

Dielectric relaxation dynamics properties of 5CB (4-cyano-4′-pentylbiphenyl) and BAC(4-[4-(S)-2-methylbutoxybenzoyloxy]benzoic acid) have been investigated. In this respect, dielectric properties of 5CB plus (1%)BAC have been compared with 5CB. The polarizing microscopy results show that BAC and 5CB exhibit enantiotropic N* mesophase and N mesophase, respectively. The real (ϵ ′) and imaginary components (ϵ′′) of dielectric constant have been calculated by capacitance method. The dielectric relaxation mechanisms of liquid crystals have been analyzed by Cole-Cole plots and the Debye distribution parameters (α) have been calculated. It has been also determined that adding BAC to 5CB increases the voltage dependent dielectric strength.