SILAR synthesized nanostructured ytterbium sulfide thin film electrodes for symmetric supercapacitors

Journal of Solid State Electrochemistry - A simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method was used for synthesis of ytterbium sulfide (Yb2S3) thin film. The...     

Design of Enterprise Storage Architecture for Optimal Business Continuity

This paper presents a solution for optimal business continuity, with storage architecture for enterprise applications, which will ensure zero data loss and quick recovery. The solution makes use of Internet protocol storage area network （IPSAN）, which is used for data management without burdening the application server, as well as mix of synchronous and semi-synchronous replication techniques to replicate data to remote disaster recovery site. We have presented the detailed design of both synchronous and semi-synchronous with case study of using open source database postgres to prove our point for optimal business continuity. The theoretical presentation is also given for the same.     

Synthesis of uniform gold nanoparticles using non-pathogenic bio-control agent: evolution of morphology from nano-spheres to triangular nanoprisms

Green synthesis of gold nanospheres with uniform diameter and triangular nanoprisms with optically flat surface was carried out using a non-pathogenic bio-control agent Trichoderma asperellum for reduction of HAuCl(4). Kinetics of the reaction was monitored by UV-Vis absorption spectroscopy. No additional capping/complexing agent was used for stabilizing the gold nanoparticles. Evolution of morphology from pseudospherical nanoparticles to triangular nanoprisms was studied by transmission electron microscopy (TEM). It revealed that three or more pseudospheres fused to form nanoprisms of different shapes and sizes. Slow rate of reduction of HAuCl(4) by constituents of cell-free fungal extract was instrumental in producing such exotic morphologies. Isolation of gold nanotriangles from the reacting masses was achieved by differential centrifugation.     

Direct transfer of micro-molded electrodes for enhanced mass transport and water management in PEMFC

Soft lithography technique is used to micropattern the electrodes on the electrolyte membrane of polymer electrolyte fuel cell (PEMFC) in order to alleviate the issues due to poor water management and inadequate reactant distribution in the fuel cell environment. Membrane electrode assembly with the micropatterned electrode has shown an increase in power density at a higher temperature as well as at a higher relative humidity when compared to a flat electrode. Consistency in cell performance is observed in the case of micropatterned electrodes.     

Nanostructured CdS/CdSSe glass composite for photonic application

The present work describes the synthesis of CdS/CdSSe glass nanocomposites and its characterization. A few glass compositions were optimized and the optimized host glass was remelted along with different semiconductors like CdS and CdSSe at high temperature. The CdS/CdSSe is present in amorphous state in the glass matrix. The thermal treatments have been carefully optimized to obtain well-defined uniform crystal growth of CdS and CdSSe. The glasses with optimized conditions were fabricated and characterized thoroughly using UV, TG/DTA and TEM. The shift in absorption edge to the longer wavelength with heat treatment implies the increase in the crystal size. The band gap has been increased with decrease in the particle size. Crystal size of semiconductors obtained by TEM was 2.5-5 nm for the glass showing absorption edge cut-off at 475 nm (CM-475).     

Rigorous analysis of delta-sigma modulators for fractional-N PLL frequency synthesis

In this paper, rigorous analyses are presented for higher order multistage noise shaping (MASH) Delta-Sigma (/spl Delta//spl Sigma/) modulators, which are built out of cascaded first-order stages, with rational DC inputs and nonzero initial conditions. Asymptotic statistics such as the mean, average power, and autocorrelation of the binary quantizer error are formulated using a nonlinear difference equation approach. An important topic of interest considered here is the fractional-N phase-locked-loop frequency synthesis applications, where the input to the modulator has to be a rational constant. It has been mathematically shown that, regardless of the initial conditions, first-order and second-order MASH /spl Delta//spl Sigma/ modulators with rational DC inputs cannot sufficiently randomize the quantization error samples, and, therefore, are not suitable for fractional-N synthesis applications. An irrational initial condition imposed on the first accumulator of a third or higher order MASH modulator, on the other hand, annihilates the tones throughout the whole output spectrum, and provides a very smooth noise shaping. Simulation results are provided to support the theoretically derived results. Implementation issues of the irrational initial condition in the digital domain are also discussed and investigated together with the effect of finite accumulator size on the noise-shaping quality factor.     

Versatile Synthetic Strategy for Coating Upconverting Nanoparticles with Polymer Shells through Localized Photopolymerization by Using the Particles as Internal Light Sources

We present a straightforward and generic strategy for coating upconverting nanoparticles (UCPs) with polymer shells for their protection, functionalization, conjugation, and for biocompatibility. UCPs are attracting much attention for their potential use as fluorescent labels in biological applications. However, they are hydrophobic and non‐compatible with aqueous media; thus prior surface modification is essential. Our method uses the internal UV or visible light emitted from UCPs upon photoexcitation with near‐infrared radiation, to locally photopolymerize a thin polymer shell around the UCPs. In this way, a large variety of monomers with different chemical functionalities can be incorporated. If required, a second layer can be added on top of the first. Our method can provide a large spectrum of surface functional groups rapidly and in one pot, hence offering a platform for the preparation of libraries of functional polymer‐encapsulated UCPs for applications in bioassays, biosensing, optical imaging, and theranostics.