Structural and electrical properties of swift heavy ion beam irradiated Co/Si interface

Synthesis of swift heavy ion induced metal silicide is a new advancement in materials science research. We have investigated the mixing at Co/Si interface by swift heavy ion beam induced irradiation in the electronic stopping power regime. Irradiations were undertaken at room temperature using 120 MeV Au ions at the Co/Si interface for investigation of ion beam mixing at various doses: 8 × 10¹², 5 × 10¹³ and 1 × 10¹⁴ cm⁻². Formation of different phases of cobalt silicide is identified by the grazing incidence X-ray diffraction (GIXRD) technique, which shows enhancement of intermixing and silicide formation as a result of irradiation.I–V characteristics at Co/Si interface were undertaken to understand the irradiation effect on conduction mechanism at the interface.     

Synthesis and characterization of indium xanthates and their use for the preparation of beta-In2S3 nanoparticles

Synthesis and characterization of various classical indium xanthate complexes of the type [InCl(3-n)(S2COR)n] (n = 1, 2, or 3; R = Me, Et, Pr(i), and Bu(s)) have been discussed. Crystalline beta-ln2S3 nanoparticles were obtained by the solvent thermolysis of indium tris-alkylxanthates in ethylene glycol at 196 degrees C, and were characterized by elemental analysis, IR, powder XRD, and XPS techniques. TEM results showed that the size of beta-In2S3 nanoparticles depended on the nature of the precursor used. The optical properties of beta-In2S3 nanocrystals have shown quantum confinement of the excitonic transition.     

Reducing session establishment delay using timed out packets in SIP signaling network

Session Initiation Protocol (SIP) has a retransmission mechanism to maintain the reliability for its real time transmission. But these real time transmissions cause overload in the server and creates redundant messages. SIP does not offer sufficient mechanisms for handling overload situations. In this paper, we study the SIP system behavior by separating signaling traffic in two different classes (Invites and Non‐invites) and creating a cut‐off priority queueing model. SIP retransmission mechanism with timeout is modeled as a queueing system with impatient customers. Using this model, the effect of unnecessary retransmissions is studied, and delay distribution and loss probability (Pb_loss) are calculated. The proposed analytical model is verified with simulations that demonstrate that the inclusion of timeout gives better delay performance. Using Pb_loss, an algorithm is developed to control the overload in hop‐by‐hop transaction as described in RFC 6357. The simulation results for the proposed model with overload control and the standard SIP as per RFC 3261 are compared. The results demonstrate that the server utilization factor of an overloaded server always remains less than one and hence avoids system collapse. Further, the redundant messages in the system are reduced by 30% as compared with the standard SIP network. Copyright © 2014 John Wiley & Sons, Ltd.     

Design and implementation of OTA based fractional-order oscillator

This paper deals with design and implementation of fractional-order (FO) oscillator based upon two topologies which employ operational transconductance amplifier (OTA). The first topology is developed on a trans-admittance mode fractional-order all-pass filter (FAPF) cascaded with an trans-impedance mode integrator whereas the other one consist of a trans-admittance mode FAPF cascaded with a trans-impedance mode differentiator. The presence of OTA makes the proposed FO oscillator electronic tunable. Both topologies are verified through SPICE simulations using 180nm CMOS technology node. The ability of proposed FO oscillator, to generate very low frequency is also explored in this work. The stability analysis is done using forlocus function of MATLAB and the mathematical equations for sensitivity of the oscillation frequency with respect to various circuit parameters are also derived. Further, to ensure the robustness of the proposed circuits process-voltage-temperature (PVT) and Monte Carlo analyses have been performed.

     

An Elliptical CPW Fed UWB Slot Antenna

A new CPW fed elliptical antenna for ultra-wideband (UWB) is proposed. The novelty of this antenna are very small size and uniplanar structure, which results in easy and low cost fabrication. This antenna has elliptical slot configuration which is fed by the CPW. This elliptical slot UWB antenna is enclosed in the extended surface of ground for decreasing the chip surface area. This antenna is designed with the optimal design parameters for the UWB spectrum. The designed antenna is printed on FR4 substrate and Vector Network Analyser is used for measuring return loss. The results of measurement results are similar to simulation results. The complete chip volume of antenna is 18.3?×?23?×?1.6 mm³.

     

Ion beam induced mixing at Co/Si interface

Ion beam mixing has emerged as a technique for understanding reactivity and chemistry at metal/Si interface and may find its applications in the field of microelectronics. We have investigated ion beam mixing at Co/Si interface induced by electronic excitation using 120 MeV Au⁺⁹ ion irradiation at different fluences, varying from 10¹² to 10¹⁴ ions/cm². Mixing was investigated by Rutherford Backscattering Spectroscopy (RBS) as a function of ion fluence and its mechanism across the interface is explained by the thermal spike model.     

Surface plasmon resonance detection of biological warfare agent Staphylococcal enterotoxin B using high affinity monoclonal antibody

A novel sensitive method was developed for the detection as well as quantification of Staphylococcal enterotoxin B (SEB) using surface plasmon resonance (SPR). It is well known that the amount of SEB needed to cause the intoxication to human beings is very less and this concentration (0.02 μg/kg) is highly dangerous, hence, it is used as biological warfare agent. Thus, the need to develop a reliable and potential detection system against SEB is warranted. In the present work, SEB antibody was immobilized on carboxymethyldextran modified gold chip. The immobilization of SEB antibody and interaction of antigen with immobilized antibody were in-situ characterized by SPR and electrochemical impedance spectroscopy. A sample solution containing SEB antigen was injected in a working channel and the results revealed linearity in the concentration from 2.0 to 32.0 pM with a detection limit of 1.0 pM. By using kinetic evaluation software, K_D (equilibrium constant) and Bmax (maximum binding capacity of analyte) values were calculated and found to be 13 pM and 424.23, respectively. Moreover, the thermodynamic parameter, change in Gibb's free energy was deduced and found to be −62.08 kJ/mol and this value shows the spontaneous interaction between SEB antigen and SEB antibody. In order to optimize the detection method, temperature and pH variation studies were also performed. Interference study was conducted to know the selectivity for the antigen-antibody interaction of SEB. The selectivity efficiency of SEB, SEC, SEA and SED were 100, 27.15, 20.01 and 12.05%, respectively towards SEB antibody.     

Corona Based Optimal Node Deployment Distribution in Wireless Sensor Networks

This paper shows the trade off between different modulation techniques such as multi level quadrature amplitude modulation, multi level phase shift keying, and multi level differential phase shift keying for upgrading direct detection optical orthogonal frequency division multiplexing systems with possible transmission distance up to 15,000 km and total bit rate of 2.56 Tb/s. The 2.56 Tb/s signal is generated by multiplexing 64 OFDM signals with 40 Gb/s for each OFDM. Variations of optical signal to noise ratio (OSNR), signal to noise ratio (SNR), and bit error rate (BER) are studied with the variations of transmission distance. Maximum radio frequency power spectrum, and output electrical power after decoder are measured for different multi level modulation techniques with carrier frequency. It is observed that multi level QAM has presented better performance than multi level PSK and finally multi level DPSK in optical OFDM systems. Maximum output power after decoder is enhanced with both 32-PSK, and 64-QAM. Quadrature signal amplitude level at encoder is upgraded with 64-QAM. It is noticed that OSNR, SNR, and BER are improved using 4-QAM OFDM system than either QPSK or 4-DPSK.     

A Dual Band Notched Ultra-Wideband Antenna

Wireless Personal Communications - In this paper, we design a planar monopole UWB antenna among two notched. Two semi-elliptical geometries are introduced at the lower and upper side’s...     

Side-Chain Liquid Crystalline Polymers with [α-terpineol-co-MMA] Main Chain: Synthesis and Characterization of Polymers with Phenyl Benzoate Mesogenic Group

Summary Side chain liquid crystalline (SCLC) [α-terpineol-co-MMA] polymers with a phenyl benzoate mesogenic group with polymethylene spacers have been synthesized and characterized in which the spacer length is taken 9 methylene units. The thermal behavior and liquid crystallinity of the polymer has been characterized using Differential Scanning Calorimetry (DSC) and Polarized Optical Microscopy (POM) techniques . The DSC curve of the LCpolymer shows glass transition at 52 °C followed by nematic phase which undergoes isotropization at 120 °C without undergoing side chain crystallization. Under optical polarized microscope the appearance of characteristic schlieren texture confirms the presence of nematic phase .