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Baihata Chariali, India

Rahman A.,Pub Kamrup College | Chakrabarty D.,Handique Girls College
International Journal of Agricultural and Statistical Sciences | Year: 2011

A method of estimation of parameters associated to a linear curve, which is simpler than the method of estimation of the same by solving the normal equations of the curve has been constructed with the help of calculus of finite difference. The method has been discussed in the case of fitting of linear curve to observed data when the values of the independent variable are at unequal intervals. Source

Choudhury N.,Pub Kamrup College | Singh F.,Inter University Accelerator Center | Sarma B.K.,Gauhati University
Radiation Effects and Defects in Solids | Year: 2013

The present study compares structural and optical modifications of lead sulfide (PbS) quantum dots under swift heavy ion (SHI) irradiation. PbS quantum dots are prepared following an inexpensive chemical route using polyvinyl alcohol as the dielectric host matrix. SHI irradiation of the samples is carried out with 100 MeV Si7+ ion beam with fluences in the range from 1×1011 to 3×1013 ions cm-2 and their structural and optical properties, before and after irradiation, are compared by X-ray diffraction (XRD), photoluminescence (PL) and UV-Vis spectroscopy. The structural parameters of PbS quantum dots are studied by X-ray line profile analysis using the Williamson-Hall plot. The values of average crystallite sizes are found to vary from 8 to 18 nm. XRD studies confirmed the formation of the cubic nanocrystalline PbS. Improvement of crystalline quality for lower fluences is exhibited by an increase in the X-ray intensities of the films. The UV-Vis absorption spectra reveal blue shift relative to the bulk material. Size enhancement of PbS quantum dots after irradiation has been indicated in XRD line profiles of the samples which has also been supported by optical absorption spectra. PL studies of all the samples are carried out with excitation wavelength 350 nm. A broad PL emission with peak centered at 473 nm is observed in pristine as well as all the irradiated samples. PL study also shows that PL intensity increases with ion fluences. © 2013 Taylor and Francis Group, LLC. Source

Choudhury N.,Pub Kamrup College
Indian Journal of Physics | Year: 2016

PbS nanoparticles have been grown in polyvinyl alcohol matrix on glass and mica substrates by chemical bath deposition method at room temperature. The structural investigation of nanocrystalline PbS has been carried out by X-ray diffraction profile analysis using Williamson–Hall and modified Williamson–Hall methods. The values of the crystallite size are found to be within the range from 10 to 17 nm having very high dislocation density of the order of 1017 m−2. The optical band gaps of the films have been determined from optical absorption measurements and found to be within the range from 2.1 to 2.8 eV. The band gap is shifted from infrared to the visible region on the account of quantum confinement in the nanostructured films due to small crystallite size. Such films, with a band gap lying in the visible region, are suitable for use as solar absorbers rather than infrared applications. © 2015, Indian Association for the Cultivation of Science. Source

Choudhury N.,Pub Kamrup College | Singh F.,Inter University Accelerator Center | Sarma B.K.,Gauhati University
Indian Journal of Pure and Applied Physics | Year: 2012

Nanocrystalline PbS prepared onto glass substrates by chemical bath deposition technique are irradiated with 100 MeV Ni8+ ion beams with different fluences from 1×10 11 to 1×10 13 ions cm -2. Analysis of the samples by X-ray diffraction show increase of average grain size from 11 nm for the pristine samples to 17 nm for the samples irradiated with 1×10 11 ions cm -2. The grain size remains constant at higher fluences. The UV-visible optical absorption measurement also show that band gap of nanocrystalline PbS decreases from 1.9 eV for the pristine samples to 1.7 eV for the samples irradiated with fluences of 1×10 11 ions cm -2 and then remains almost constant. It is observed from photoluminescence (PL) study that the PL intensity increases for irradiated samples with minimum intensity for pristine sample. Source

Haloi H.,Pub Kamrup College | Borah J.,Arya Vidyapeeth College | Datta L.,Gauhati University
Transactions of the Institute of Indian Geographers | Year: 2014

The Education For All (EFA) is a worldwide novel mission of UNESCO which is centered around six goals. While each of the six EFA goals is individually important, it is also useful to have a means of indicating progress towards EFA as a whole. The EFA Development Index (EDI), a composite of relevant indicators, provides one way of doing so at least for the four most easily quantifiable EFA goals. The present study is an attempt to examine three components of Education For All Development Index namely Universal Primary Education (UPE), Quality of Education and Gender Parity and Equality and finally to assess Primary Education EDI of four Community Development Blocks of Assam identified to represent four socio-economically backward communities namely Tea Garden Labour community, Char community, Scheduled Tribe community and Scheduled Caste community respectively. The study is based on secondary data which have been analyzed and discussed with necessary statistical techniques and inferences are drawn based on them. The EDI of the selected blocks are far below the countries average which may be related to literacy status. The situation demands a systematic approach for attaining the goal of Universal Primary Education by the socio-economically backward communities of Assam. Source

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