[en] Nanocomposites of conducting polyaniline (PAni) and cadmium sulphide (CdS) has been synthesized via in situ generation of CdS from highly reactive organometallic cadmium precursor i.e. dimethyl cadmium (DMCd) in N,N'-dimethyl formamide (DMF). UV-Vis absorption spectra of PAni-CdS nanocomposite showed λ_(max) at about 440-445 nm in addition to the bands present at ∼325 and ∼615 nm due to PAni. The absorption band at ∼440-445 nm is identified due to nanosized CdS particles indicating a blue shift of about >70 nm with respect to bulk CdS. The X-ray diffraction pattern showed broad peaks due to formation of nanoparticles of CdS in polyaniline matrix. Scanning electron microscopy (SEM) showed that the particles are in agglomerated form. Organometallic compound i.e. dimethyl cadmium (Me₂Cd) is used for the first time with polyaniline for CdS nano particles

[en] Cadmium selenide has been synthesized directly from cadmium chloride in aqueous N,N'-dimethylformamide (DMF) by the use of cycloocteno-1,2,3-selenadiazole or the element itself as the source of selenium. The dark brown powders that are the end-products of these reactions were characterized by reflectance spectroscopy, powder X-ray diffraction and scanning electron microscopy

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No abstract available

[en] When barley varieties (Ratna, C-164 and Jyoti) were grown under identical conditions of soil and applied phosphatic fertilizer a difference in the proportion of P derived from the fertilizer in the plant (Pdff) was noticed. Ratna could utilize maximum and Jyoti the minimum proportion of P from the applied source. In a separate experiment F₁ hybrid obtained by crossing DL-70 and Ratna showed the percent Pdff very close to midparent value. (author)

[en] This paper presents the efforts made to study the process of comminution to Weiss domain polarization and phase transition in piezoceramics together with the versatility of low-temperature-cofired ceramics-based devices and components for their ready adoption for typical applications in the area of micro-fluidics. A conceptual micro-fluidic module has been presented and few unit entities necessary for its realization have been described. The purpose of these entities is to position the sensors and actuators by using piezoelectric materials. Investigations are performed to make useful constructions like diaphragms and cantilevers for laying the sensing elements, cavities for burying the electronic chip devices, and channels for fluid transportation. In order to realize these constructions, the basic step involves machining of circular, straight line, rectangular and square-shaped structure in the green ceramic tapes followed by lamination and firing with post-machining in some cases. The diaphragm and cavity includes one or more un-machined layer stacked together with several machined layers with rectangular or square slits. The cantilever is an extension of the diaphragm creation process with inclusion of a post-machining step. The channel essentially consists of a machined green ceramic layer sandwiched between an un-machined and a partially machined layer. The fabrication for all the above constructions has been exemplified and the details have been discussed

[en] Freshly prepared CdS-quantum dots (QDs) in DMF (clear pale solution) when loaded in polymethylmethacrylate (PMMA) lead to excellent optical properties. The tuning of the absorption and emission wavelengths via experimentally control parameters is considered novel and significant. The absorption band for CdS was observed at about 370 nm in polymeric matrix. The blue, green and orange light emissions from such composite solution were tuned and stabilized by simply varying the concentration of CdS, cadmium and sulphur in the final product. Photoluminescence (PL) measurement with 2% CdS loading showed band-edge emissions from the composite with only about 20-25 nm Stokes shift in emission wavelength. Observation of such optical properties indicated that the composite has narrow particle size distribution and particle diameter may well be below 10 nm. X-ray diffraction (XRD) patterns of the film with higher loading of CdS showed broad pattern for hexagonal CdS. Thermo-gravimetric analysis (TGA) of CdS/PMMA composite film revealed that it has better thermal stability than PMMA alone. Transmission electron microscopy (TEM) showed agglomerated tiny dots in nano-meter regime

[en] One-step in situ preparation of silver nano-particles in polymethylmethacrylate (PMMA) using N,N'-dimethylformamide (DMF) as a medium has been performed successfully. The radical polymerization of methaycrylic acid (MMA), in presence of benzoyl peroxide followed by reaction of silver source has been successfully employed to synthesize Ag/PMMA nano-composite. A light yellow solution in its UV-Vis absorption spectrum showed surface plasmon resonance absorption bands between 410 and 425 nm in solutions and at about 452 nm in a transparent film. The Ag/PMMA nano-composite was characterized by X-ray diffraction (XRD) measurement, transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform-infrared spectroscopy (FT-IR) and thermo-gravimetric analysis (TGA). XRD showed the fcc crystal structure of the bulk Ag with particles of less than 25 nm in size similar to that is observed by TEM. SEM indicated uniform distribution of particles in the film. TGA confirmed enhanced thermal stability of the polymer

[en] CdSe quantum dots (QDs) prepared using an aqueous sodium selenosulphite and N,N'-dimethylformamide (DMF) in commercial polymethylmethacrylate (PMMA) showed excellent optical properties. Tuning of the absorption and emission wavelengths by varying the selenium concentration with respect to cadmium is studied. As-prepared CdSe quantum dots showed absorption band at 405 nm (3.06 eV) associated with the formation of 'early-stage' CdSe nano-particles along with weak absorption at 480-90 nm due to continuous growth of the particles. The blue-green and yellow-green light emissions were observed from as-prepared solutions. Photoluminescence (PL) measurement showed band-edge emissions at around 430 nm for small clusters but a more stable emission at 544 nm for the 1:1 CdSe sample. X-ray diffraction (XRD) pattern of the CdSe/PMMA powder with Cd/Se ratio of 1:1 showed broad pattern for cubic CdSe. Transmission electron microscopy (TEM) showed cube like de-shaped spherical dots in the region of about 5 nm.

[en] Cycloocteno-1,2,3-selenadiazole, an organometallic selenium precursor reacts with mercury acetate in aq. N,N'-dimethylformamide (DMF) or in ethylene glycol (EG) at a temperature between 120 and 130 deg. C to afford nano-sized HgSe. The product was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy TEM. The electron diffraction analysis showed crystalline nature of nano-particles of HgSe. The calculation made by XRD suggest the particles size to be less than 20 nm which match well with the observations made by TEM. The current method uses 1,2,3-selenadiazole, an organo-selenium compounds thus extending the scope of organo-chalcogen compound in material science