48 research outputs found
Electrical Properties of Poly-N-Epoxypropylcarbazole/Vanadium Pentoxide Composite
In the present work the electrical properties of poly-N-epoxypropylcarbazole (PEPC) and vanadium pentoxide (V2O5) composite have been studied. The composite was formed by mixing of PEPC solution in benzene with V2O5 powder and stirring at room temperature. The composite solution was deposited on a dielectric substrate with copper electrodes and the Cu/PEPC-V2O5/Cu surface type film samples were fabricated. The Cu/V2O5/Cu samples were used as a reference where the films were deposited from the mixture of V2O5 powder in distilled water. Resistance-temperature relationship and voltage-current characteristics of the composite and V2O5 samples were studied by using conventional digital voltmeter and ammeter in the temperature range of 27-110 °C with an error of ±0.5%. It was observed that the DC electrical conductivity, activation energy and non-linearity of voltage-current characteristics of the samples are temperature dependent. It was found that the temperature dependence of electrical conductivity of the V2O5 samples on the whole obeys T-1/4 law whereas the PEPC-V2O5 ones show visible deviations from that. The PEPC-V2O5 samples may be used as thermistors as the temperature coefficient of their resistance is large and at 27 °C is equal to -4.7%/°C
Experimental investigation of the effect of insulator sleeve length on the time to pinch and multipinch formation in the plasma focus facility
The Photo-Electrical Behavior of n-Si and p-Si/Orange Dye/ Conductive Glass Cells
The photo-electrical behavior of n-Si/orange dye/conductive glass and p-Si/orange dye/conductive glass sandwich type cells were investigated. In these cells crystal silicon of n-type and p-type and conductive glass (CG) electrodes were employed and the aqueous solution of organic dye (OD) was used as an electrolyte in the distilled water. Under filament lamp illumination, photo-induced open-circuit voltage and shortcircuit current exponentially dropped with time for the n-Si/orange dye/CG cell. In the p-Si/orange dye/CG cell, the photovoltaic effect was not observed. The n-Si/OD/CG cell showed high photo-electrical response under illumination. In the light-voltage/current conversion, these cells behaved as a differentiator and exhibited charge-storage properties
Effect of Temperature and Humidity on Electrical Properties of Organic Orange Dye Complex Films
In this study the effect of temperature and humidity on electrical properties of organic orange dye (OD) complex with vinyl-ethynyl-trimethyl-piperidole (VETP) have been examined. Thin films of OD (C17H17N5O2) and VETP (C12H19NO) complex were deposited from 10 wt.% (5 wt.% of each matter) solution in mixture of distilled water (80%) and spirit. The films were grown at room temperature under normal gravity conditions, i.e., 1 g and in a spin coater at an angular speed of 300 RPM. The Cu/OD-VETP/Cu surface type samples were fabricated and their low frequency (10 Hz) AC electric characteristics were evaluated for the temperature range 30-95 °C at ambient humidity of 45-80%. It was observed that at normal conditions the conductivity of the samples is temperature dependent and shows semi-conductive behavior with activation energy of 0.55 eV. It was found that with increase in humidity the resistance of the samples decreases and at humidity values equal to 60-70% the irreversible transition from semi-conductive to conductive state takes place. It is supposed that in the former state the conductive matrix is formed due to incorporation of the water molecules into OD-VETP complex
Structural and Mechanical Properties of Radiofrequency Ar-N2 Plasma Nitrided Aluminium
Enhancement of X-ray emission in the side on direction in a Mather-type plasma focus
A 1.8Â kJ Mather-type plasma focus (PF) for argon and hydrogen
filling is examined. Two anode configurations are used. One is tapered
towards the anode face, and the other is cylindrical but the face is cut at
different angles. At optimum conditions, the system is found to emit Cu–Kα
X-rays of about 1.6±0.1 J/sr in the side-on direction for argon
filling, which
is about 32% of the total X-ray emission. In 4Ï€-geometry, maximum
total X-ray
yield and wall plug efficiency found are 26.4±1.3 J and 1.5±
0.1%
respectively. The modified geometry may help to use the PF as a radiation
source for X-ray diffraction
Deposition of titanium nitride on AISI-304 in a plasma focus environment
Polycrystalline, smooth, and hard thin films of TiN are successfully
deposited on AISI-304 substrates using a 1.5Â kJ Mather-type dense plasma
focus device charged at 18Â kV. The purpose of this study is to investigate
the structural and mechanical properties of the TiN thin films in terms of
ion dose and substrate position to establish the optimum deposition
conditions. The films are analyzed using XRD, SEM, electron microprobe and
micro-hardness testing. XRD confirms the deposition of a polycrystalline TiN
thin film together with the emergence of an iron chromium nickel phase. The
surface hardness-in comparison to the unexposed substrate-is found to
increase up to 250% when a film is deposited using 30 focus shots at an
axial distance of 6Â cm. SEM micrographs show that the quality of the film is
improved with an increasing number of focus shots. The constituent elements
of the film are also confirmed by electron microprobe
Spectroscopic optimization of abnormal glow conditions for plasma ion nitriding
Optical emission spectroscopy is used to characterize the production of
active species as a function of hydrogen concentration in the mixture under
different operating conditions. A major concern is to enhance the
concentration of the active species by hydrogen addition that carry several
electron volts energy above their ground states, and thus affect the surface
chemistry. The emission intensity of the selected optical transitions of
molecular and atomic species is measured to determine the functional
dependence of their radiative states. The relative ground state molecular
ion density [N2+] is measured from the emission intensity of the
first negative band head (λ = 391.4 nm, 0–0) by considering the
fact that in low temperature plasma, ion with single charge is produced by
the electron impact, and the ion density is proportional to the electron
density. It is found that the concentration of the active species may be
enhanced significantly by selecting an appropriate gas composition and
operating parameters. The SS-304 samples are nitrided under the optimum
conditions for 4, 8, 12 and 16 hours and hardness values are found to
increase five times for 16 hours treatment time. The optimized discharge
conditions are found favorable for plasma ion nitriding
Mode transition in magnetic pole enhanced inductively coupled argon plasmas
The electrical probe (Langmuir probe) diagnostics of different plasma parameters and
operation regimes (E/H modes) of magnetic pole enhanced, inductively coupled (MaPE-ICP)
argon plasmas are investigated. It is shown that uniform, high density
(ne ~ 1012 cm-3)
and low electron temperature
(Te ~ 1.5 eV) plasma can be produced
in low pressure argon discharges at a low power (100Â W). It is found that an MaPE-ICP
reactor operates in two different modes; capacitive (E mode) and inductive (H mode). No
density jump or hysteresis are reported between these modes. The effect of pressure on
transition power, where the mode changes from E to H mode at 20Â sccm gas flow rate are
studied and it is found that for all pressures tested (~Â 7.5Â mTorr to 75Â mTorr)
the transition power remains same. In the inductive mode, the above plasma parameters show
a smooth variation with increasing filling gas pressure at fixed power. The intensity of
the emission line at 750.4Â nm due to
2p1 → 1s2 (Paschen’s notation)
transition, closely follows the variation of
ne with RF power and filling gas pressure.
Measured electron energy probability function (EEPF) shows that electron occupation mostly
changes in the high-energy tail, which enlightens close similarity of the
750.4Â nm argon line to electron number density
(ne). The behaviour of the electron
energy probability function (EEPF) with regard to pressure and RF power in two operational
modes is presented