Influence of temperature and frequency on electrical properties of electron beam evaporated bromoaluminum phthalocyanine, BrAlPc, thin films

The AC electrical properties of electron beam evaporated Bromoaluminum phthalocyanine (BrAlPc) thin films have been studied in the frequency range 10²–10⁵ Hz and in the temperature range of 303–413 K. The BrAlPc thin films are characterized by field emission scanning electron microscopy (FESEM). The capacitance is found to be sensitive to the frequency and increases with increasing temperature and decreases with increasing frequency. A loss minimum has been observed in the frequency dependence of the dissipation factor. Such behavior is found to be in good qualitative agreement with the model of Goswami and Goswami. The AC conductivity $\sigma \left( \omega \right)$ σ ( ω ) is found to vary as $\omega^{s}$ ω s in the studied frequency range. At frequencies 10–10² Hz, s is less than unity and decreases with increase in temperature indicating a dominant hopping process. At frequency ranges 10²–10⁴ Hz, exponent s lies very close to the unity and is independent of temperature, which shows the quantum mechanical tunneling is dominated conduction mechanism. At higher frequencies 10⁴–10⁵ Hz, s is found to be temperature independent. The temperature dependence of AC conductivity shows a linear increase with the increase in temperature. Moreover, the activation energies of device are determined as a function of frequency.     

Untersuchung der Legierung THX 540 (AlMg5Si2Mn) in Abhängigkeit von verwendeten Thixoparametern

In this study the entire thixocasting process was examined. The aim was to optimize the process and thus improve the quality of the as-cast part. To successfully produce a thixocast part, the choice of appropriate alloy composition, the appropriate microstructure within the billet and the appropriate heat treatment of the billets into the semisolid state were found to be critical. In order to determine the influence of the alloy composition on fraction solid, simulations using Thermocalc® were conducted. For the special microstructure of the billets the cell size was examined. To determine the characteristics of the castings the circularity, the intermetallic phases (examined with SEM) and the casting defects were investigated. The casting examined was manufactured for use in the automobile industry.     

Relations Between the Plasma Diamagnetic Effect and Plasma Basic Parameters in IR-T1 Tokamak

Precise determination of the poloidal Beta, internal inductance, plasma energy, plasma pressure, plasma temperature, plasma resistance, plasma effective atomic number, and plasma energy confinement time are essential for tokamak experiments. In this paper an experimental method especially based on the plasma diamagnetic effect for measurements of these parameters in IR-T1 tokamak are presented. For these purposes a diamagnetic loop with its compensation coil, and also an array of magnetic probes designed, constructed, and installed on outer surface of the IR-T1. Also in this work we measured the Shafranov parameter, plasma current, plasma voltage, and the plasma density by the magnetic probes, Rogowski coil, poloidal flux loop, and the Langmuir probe measurements, respectively.     

Turbulent Transport in the Tokamak Edge Plasma and SOL Region

In this work, the turbulent transport in the edge plasma and Scrape-Off Layer (SOL) region of IR-T1 tokamak at the presence of biased limiter has been investigated and analyzed. The time and radial evolution of floating potential, electric field and turbulent transport have been measured by using two arrays of the Langmuir probes in both the radial and poloidal directions. The analyses have been done by the Fast Fourier Transport method and spectral features of them are obtained with the help of the standard Auto-Correlation technique and modified covariance power spectral density estimate. The probability distribution function and actual transfer function magnitude of the radial and poloidal turbulent transport (Γ_r and Γ_p) have been investigated and compared in the edge plasma and SOL region. Also the histogram of turbulent transport has been analyzed and compared in the edge and SOL at presence of positive limiter biasing. The results show that in the edge plasma poloidal turbulent transport (Γ_p) is about of 60 % more than SOL region whereas radial turbulent transport (Γ_r) is about of 40 % less. During the application of positive biasing, it was found that Γ_r in the IR-T1 reduces by about 80 % in the edge plasma and 45–50 % in the SOL. Increase of Γ_p is about of 50 % after applied positive biasing in the edge while it increases 70 % nearly, in the SOL. Consequently, the improvement in confinement can be obtained for positive limiter biasing.     

Astute,fine and fast method of iris segmentation in unlimited circumstances

Neural Computing and Applications - Currently, Iris detection is considered as a significant module for robust biometric systems and high-speed applications such as eye tracking. Most iris...