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P. Arun

Publications and source records attributed to P. Arun.

At least 37 records · Page 2Linked to original sources

Deposition of Diamond-like Carbon films using Dense Plasma Focus

Diamond Like Carbon (DLC) films were deposited on quartz substrates using Dense Plasma Focus (DPF) method. The formation of ${\rm sp^3}$ bonds as is it's content in the film strongly depends on the substrate and it seems quartz is not a suitable substrate. However, we report here the formation of DLC films on quartz substrates that were maintained at elevated temperatures and show the content of carbon atoms with ${\rm sp^3}$ bonds in the film is directly proportional to the substrate's temperature. Not only does this give good control of film fabrication, but also shows how to take advantage of DLC film's anti-wear, scratch resistant properties on material surfaces that require protection.

cond-mat.mtrl-sci↗

Considerations for Anderson-Bridge Experiment

Various issues concerned with the design and sensitivity of the Anderson bridge are discussed. We analyse the circuit using the tools of Network Analysis to determine the conditions under which the balance may be obtained with greater sensitivity and discuss how to obtain these under practical circumstances in an undergraduate laboratory.

physics.class-ph↗

Characterization of ZnO:Si Nanocomposite Films Grown by Thermal Evaporation

Nanocomposite thin films of Zinc Oxide and Silicon were grown by co-evaporating powdered ZnO and Si. This resulted in nanocrystallites of ZnO being embedded in Silicon. The mismatch in crystal structures of constituent materials result in the ZnO nanocrystals to exist in a state of stress. This along with oxygen vacancies in the samples result in good Photoluminescence emission at 520nm. Also, Silicon background gave a photoluminescence emission at 620nm. The structure was found quite stable over time since the homgenously dispersed ZnO nanocrystals do not agglomerate. The nanocomposites promises to be a useful candidate for future optoelectronic devices.

cond-mat.mtrl-sci↗

Band Gap of CsCl Film's as a Function of Lattice Constant

The manuscript reports experimental estimation of Cesium Chloride film's band gap and compares it with theoretical simulations. The band gap shows a strong dependence on it's lattice constant. Also, it is seen that the point defects present in the films strongly affects it's optical properties.

cond-mat.mtrl-sci↗

Threadbare Parallel Port DAQ Card

A very simple Data acquisition card was developed in our under-graduate class for interfacing with the parallel port of a standard computer. It was developed with the intention to enable students to do various physics experiments with the computer sparing them from knowing the details of the electronics required. The article is a summary of our experience and ends with a request for suggestions to improve the circuit without losing its simplicity.

physics.ed-ph↗

Voltage Controlled Resistance

The paper discusses an application of the field effected transistor (FET) as a voltage controlled resistance which can be done in under-graduate labs either as a routine experiment or as a project.

physics.ed-ph↗

Alternative Method for Studying Color Centers in CsCl Thin Films

The optical properties of cesium chloride (CsCl) are changed with presence of vacancies in the crystal structure giving rise to what is called as "color centers". We have unconventionally adopted Tauc's method to determine the characteristic color centers and have modeled the correlation among the film optical properties and lattice size, highlighting the interrelation between the structural and optical properties of alkali halide films.

cond-mat.mtrl-sci↗

Reaction Time of a Group of Physics Students

The reaction time of a group of students majoring in Physics is reported here. Strong co-relation between fatigue, reaction time and performance have been seen and may be useful for academicians and administrators responsible of working out time-tables, course structures, students counsellings etc.

physics.ed-ph↗

Modeling, Performance Analysis and Comparison of Two Level Single Chain Pointer Forwarding Strategy For Location Management in Wireless Mobile Communication

Global wireless networks enable mobile users to communicate regardless of their locations. Location management is an important part of the emerging wireless and mobile technology. A Personal Communication System (PCS) network must have an efficient way to keep track of the mobile users to deliver services effectively. Global System for Mobile Communication (GSM) is a commonly accepted standard for mobility management of mobile users. Location management involves location tracking, and location information storage. Location management requires mobile users to register at various registration areas whenever they are on the move. The registration process may cause excessive signaling traffic and long service delays. To improve the efficiency of location tracking and avoid call set up delays, several strategies such as local anchor scheme, per-user caching scheme and several pointer forwarding schemes have been proposed in the past. In this paper, we propose a new "Two Level Single Chain Pointer Forwarding (TLSCP) Strategy" in which a two level hierarchy of level-1 and level-2 forwarding pointers reduced to single chain length are used. Organizing the pointers in a two level hierarchy and further restricting the pointer chain lengths at both the levels to single chain localizes the network signaling traffic and reduces the call set up delays. To justify the effectiveness of our proposed strategy, we develop an analytical model to evaluate the signaling cost. Our performance analysis shows that the proposed dynamic TLSCP scheme can significantly reduce the network signaling traffic and cost for different categories of users under different network conditions.

physics.data-an↗

Study of the Damped Pendulum

Experiments on the oscillatory motion of a suspended bar magnet throws light on the damping effects acting on the pendulum. The viscous drag offered by air was found the be the main contributor for slowing the pendulum down. The nature and magnitude of the damping effects were shown to be strongly dependent on the amplitude.

physics.ed-ph↗

Motion of falling object

A simple setup was assembled to study the motion of an object while it falls. The setup was used to determine the instantaneous velocity, terminal velocity and acceleration due to gravity. Also, since the whole project was done within $20 it can easily be popularized.

physics.ed-ph↗

On the Structure of ${\rm ZnI_2}$

A new structure for ${\rm ZnI_2}$ is proposed which it exists in tetragonal state. In this structure the ${\rm ZnI_2}$ molecule exists in a nonlinear array and forms the basis of the tetragonal unit cell with one basis per unit cell. The structural analysis based on the reflections listed in ASTM 30-1479 shows that the proposed structure is correct.

cond-mat.mtrl-sci↗

Study of ${\rm CdI_2}$ nanocrystals dispersed in amorphous ${\rm Sb_2S_3}$ matrix

Crystalline nanoparticles of cadmium iodide where suspended in the amorphous matrix of antimony trisulphide. Both materials are layered structured and have large band-gaps however cadmium iodide exhibits polytypism, i.e. it exists in various different crystalline states. Different crystalline states are marked by wholely different dielectric constants which give rise to sharp surface plasmon resonance (SPR) peaks in the UV-visible. The manuscript details the variation in SPR's with heat-treatment of the films.

cond-mat.mtrl-sci↗

Simple 8085 microprocessor compatible I/O card

A simple interfacing project with the 8085-microprocessor kits available in under graduate college labs has been discussed. The interface card to study the I-V characteristics of a p-n diode emphasizes how the microprocessor can be used to do experiments in physics. Also, since the whole project was done within Rs400/- it can easily be popularized.

physics.ed-ph↗

Simple Pendulum Revisited

We describe a 8085 microprocessor interface developed to make reliable time period measurements. The time period of each oscillation of a simple pendulum was measured using this interface. The variation of the time period with increasing oscillation was studied for the simple harmonic motion (SHM) and for large angle initial displacements (non-SHM). The results underlines the importance of the precautions which the students are asked to take while performing the pendulum experiment.

physics.ed-ph↗

Hystersis like behaviour in Thin Films with heating-cooling cycle

The expression of temperature distribution along a film thickness is derived and distribution of temperature in the film as the substrate is heated is shown. The variation of film resistance with different substrate temperature is calculated and the existence of temperature gradient along the film thickness with finite thermal conductivity leads to hysteresis like behaviour on heating-cooling the film.

cond-mat.mtrl-sci↗

Influence of Grain size on the Electrical Properties of ${\rm Sb_2Te_3}$ Polycrystalline Films

Resistance of vacuum deposited ${\rm Sb_2Te_3}$ films of thickness between 100-500nm has been measured in vacuum. It is found that the resistance of the polycrystalline films strongly depends on the grain size and inter-granular voids. The charge carrier are shown to cross this high resistivity inter- granular void by ohmic conduction. The barrier height as well as temperature coefficient of resistance are also shown to depend on the grain size and inter- grain voids.

cond-mat.mtrl-sci↗

Effect of Plasma Irradiation on $Cd I_2$ films

The effect of plasma irradiation is studied systematically on a 4H polytype (002) oriented ${\rm CdI_2}$ stoichiometric film having compressive residual stress. Plasma irradiation was found to change the orientation to (110) of the film at certain moderate irradiation distances. A linear decrease in grain size and residual stress was observed with decreasing irradiation distance (or increasing ion energy) consistent with both structural and morphological observations. The direct optical energy gap ${\rm E_g}$ was found to increase linearly at the rate ${\rm 15μeV/atm}$ with the compressive stress. The combined data of present compressive stress and from earlier reported tensile stress show a consistent trend of ${\rm E_g}$ change with stress. The iodine-iodine distance in the unit cell could be responsible for the observed change in ${\rm E_g}$ with stress.

cond-mat.mtrl-sci↗