Efficient and realistic device modeling from atomic detail to the nanoscale

As semiconductor devices scale to new dimensions, the materials and designs become more dependent on atomic details. NEMO5 is a nanoelectronics modeling package designed for comprehending the critical multi-scale, multi-physics phenomena through efficient computational approaches and quantitatively modeling new generations of nanoelectronic devices as well as predicting novel device architectures and phenomena. This article seeks to provide updates on the current status of the tool and new functionality, including advances in quantum transport simulations and with materials such as metals, topological insulators, and piezoelectrics.Comment: 10 pages, 12 figure

Night sky at the Indian Astronomical Observatory during 2000-2008

We present an analysis of the optical night sky brightness and extinction coefficient measurements in UBVRI at the Indian Astronomical Observatory (IAO), Hanle, during the period 2003-2008. They are obtained from an analysis of CCD images acquired at the 2 m Himalayan Chandra Telescope at IAO. Night sky brightness was estimated using 210 HFOSC images obtained on 47 nights and covering the declining phase of solar activity cycle-23. The zenith corrected values of the moonless night sky brightness in mag/square arcsecs are 22.14(U), 22.42(B), 21.28(V), 20.54(R) and 18.86(I) band. This shows that IAO is a dark site for optical observations. No clear dependency of sky brightness with solar activity is found. Extinction values at IAO are derived from an analysis of 1325 images over 58 nights. They are found to be 0.36 in U-band, 0.21 in B-band, 0.12 in V-band, 0.09 in R-band and 0.05 in I-band. On average, extinction during the summer months is slightly larger than that during the winter months. No clear evidence for a correlation between extinction in all bands and the average night time wind speed is found. Also presented here is the low resolution moonless optical night sky spectrum for IAO covering the wavelength range 3000-9300 \AA. Hanle region thus has the required characteristics of a good astronomical site in terms of night sky brightness and extinction, and could be a natural candidate site for any future large aperture Indian optical-infrared telescope(s).Comment: 18 pages, 7 figures, uses basi.cls, accepted for publication in Bulletin of the Astronomical Society of Indi

Cocoa Care - An Android Application for Cocoa Disease Identification

India is an agricultural country. The correct and timely identification of diseases in crops is very much essential in agriculture. To obtain more valuable products, a product quality control is basically mandatory. Cocoa is an economically important crop that nowadays enlarges its production in southern India. To assist the farmers growing cocoa, we developed an android application Cocoa-Care. This application automatically identifies the diseases of cocoa crops, thereby helps the farmers who have little or no information about the disease. This application is developed by applying digital image processing techniques on the diseased cocoa images. Our approach replaces the manual disease inspection by the android application that identifies the cocoa disease from the captured image and suggests the possible remedies for the farmer. We used moment based texture features for the image representation and description. The matching is performed by nearest neighbor classifier. The results obtained are promising and this application can be used in the real time

Role of neutron transfer in the reaction mechanism of 9^9Be+169^{169}Tm, 181^{181}Ta, 187^{187}Re and 197^{197}Au systems

The contribution of one neutron stripping cross section to the total reaction cross section has been studied for $^9$Be projectile incident on $^{169}$Tm, $^{181}$Ta, $^{187}$Re and $^{197}$Au targets around Coulomb barrier energy. The measured one neutron stripping cross sections for these systems have been compared with the coupled channel calculations. The recently developed global set of optical model potential parameters for $^9$Be projectile has been used in the present calculations. The cumulative of measured complete fusion (CF), incomplete fusion (ICF), one neutron stripping and calculated non-capture breakup (NCBU) cross sections is found to explain almost the reaction cross sections for all the targets. A very small contribution from target inelastic states and elastic breakup may contribute to the remaining part. The percentage fraction of cross section for CF, ICF, one neutron stripping, and NCBU over reaction cross section show the dominance of neutron transfer and NCBU at below barrier energies while CF and ICF processes have the major contribution at above barrier energies.Comment: 12 pages, 3 figure

Acoustic-Phonon Mediated Cyclotron Resonance Power Absorption in Zinc Oxide Free-Standing Nanostructure

157-162The phenomenon of cyclotron resonance power absorption when electrons are scattered by acoustic-phonons in ZnO free standing nanostructure (FSNS) is presented. The calculation is based on quantum mechanical perturbation technique. The dependence of power absorption on frequency, magnetic field, temperature and thickness of the FSNS is presented. FWHM or line-width of the resonance power absorption peaks is calculated using profile method and the influence of magnetic field, temperature and thickness of the FSNS is investigated, that the line-width is proportional to magnetic field whereas it is independent of temperature and thickness of FSNS. This theoretical analysis gives insights about magneto-optical properties of FSNS of ZnO which is essential for further experimental investigations

Acid-base properties of Cu<SUB>1-x</SUB>Co<SUB>x</SUB>Fe<SUB>2</SUB>O<SUB>4</SUB> ferrospinels: FTIR investigations

Systematic IR spectroscopic studies were undertaken to investigate the acid-base properties of Cu-Co ferrospinels Cu1-xCoxFe2O4 (x=0 to 1) employed in phenol methylation to produce 2,6-xylenol. The IR spectra of the ferrospinels reveal that Fe3+ and Co2+ ions are mainly responsible for the various hydroxy groups on the surface. Temperature dependent IR studies of pyridine adsorbed on spinels and on the spinel phase with deliberately added metal oxide exemplify the contribution of the metal ions and their coordination state towards Lewis acidity. IR studies of the spinel surface with adsorbed CO2 and adsorption studies of electron acceptors such as 7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrachloro-1-4-benzoquinone and p-dinitrobenzene were carried out to evaluate the nature of the basic sites and the strength and distribution of the electron donor sites present on the spinel surface. It was found that the acidity (basicity) of the Cu1-xCoxFe2O4 spinel system increases (decreases) from x=0 to 1. A correlation between acidity, basicity and catalytic performance reveals that an intermediate acid-base character enhances the phenol methylation activity

Effect of charge distribution on the translocation of an inhomogeneously charged polymer through a nanopore

We investigate the voltage-driven translocation of an inhomogeneously charged polymer through a nanopore by utilizing discrete and continuous stochastic models. As a simplified illustration of the effect of charge distribution on translocation, we consider the translocation of a polymer with a single charged site in the presence and absence of interactions between the charge and the pore. We find that the position of the charge that minimizes the translocation time in the absence of pore--polymer interactions is determined by the entropic cost of translocation, with the optimum charge position being at the midpoint of the chain for a rodlike polymer and close to the leading chain end for an ideal chain. The presence of attractive or repulsive pore--charge interactions yields a shift in the optimum charge position towards the trailing end and the leading end of the chain, respectively. Moreover, our results show that strong attractive or repulsive interactions between the charge and the pore lengthen the translocation time relative to translocation through an inert pore. We generalize our results to accommodate the presence of multiple charged sites on the polymer. Our results provide insight into the effect of charge inhomogeneity on protein translocation through biological membranes.Comment: Submitted to Journal of Chemical Physic

Oral candidiasis in Chikungunya viral fever: a case report

A 32 year old Indian male patient presented with chief complaints of a high fever, erythema on ear, severe polyarthritic joint pains & swelling, non pitting pedal oedema, facial puffiness and itching for past four days. He had no significant past medical and drug history and was serologically confirmed to have Chikungunya. Oral cavity inspection revealed whitish non erythematous pseudo membranous plaques on the hard palate, buccal surface of cheek and the floor of the mouth which was later microbiologically confirmed as Candidiasis. He tested negative for HIV and had leucopenia with severe CD4 T-lymphocytopenia. This is the first report of an opportunistic infection with CD4 T-lymphocytopaenia in Chikungunya fever