Rapid advances in nanotechnology have led to its emergence as a tool for the development of green... more Rapid advances in nanotechnology have led to its emergence as a tool for the development of green synthesized noble metal nanoparticles, especially silver nanoparticles (AgNPs), for applications in diverse fields such as human health, the environment and industry. The importance of AgNPs is because of their unique physicochemical and antimicrobial properties, with a myriad of activities that are applicable in various fields, including the pharmaceutical industry. Countries with high biodiversity require the collection and transformation of information about biological assets into processes, associations, methods and tools that must be combined with the sustainable utilization of biological diversity. Therefore, this review paper discusses the applicable studies of the biosynthesis of AgNPs and their antimicrobial activities towards microorganisms in different areas viz. medicine and agriculture. The confirmed antiviral properties of AgNPs promote their applicability for SARS-CoV-2 t...
Abstract Pure and Cu/Mn-doped Cd0.4Zn0.6O (0 ≤ x ≤ 1) ternary alloy is prepared by co-precipitati... more Abstract Pure and Cu/Mn-doped Cd0.4Zn0.6O (0 ≤ x ≤ 1) ternary alloy is prepared by co-precipitation and further the variation of dopant concentration has been studied. The diffractogram of the undoped sample has peaks of both rocksalt (RS) CdO and wurtzite (WZ) ZnO phase. The individual and simultaneous doping of Cu and Mn elements has significantly altered the intensity, FWHM, and developments of defect states in Cd0.4Zn0.6O alloy. TEM microscope has investigated the crystalline size and interplanar spacing that is slightly decreased with dopant concentration which lies within the range ~ 38–30 nm. UV–Vis spectroscopy analyzed a decreasing trend in bandgap energy with dopant concentration. IN PL, the near band edge and deep trap state emission is observed at 382, 417, 448, 520 and 580 nm wavelengths. The resistivity, carrier concentration, and mobility are also computed which proposed that Cu/Mn-doped Cd0.4Zn0.6O alloy could be the better TCO with new opportunities for material science researchers.
Ceria (CeO 2) nanocrystals dispersed in silica were prepared by sol-gel, a very suitable method f... more Ceria (CeO 2) nanocrystals dispersed in silica were prepared by sol-gel, a very suitable method for large-scale production. The formation of cubic fluorite structure of CeO 2 nanocrystals was confirmed by XRD, TG-DTA and TEM. The average nanocrystalline size has been calculated~3-5 nm using Debye-Scherrer formula for different annealed samples. The calculated nanocrystalline sizes were compared with W-H plot and TEM histograms. Different structural parameters like microstrain, lattice constant, dislocation density, X-ray density and activation energy were also calculated for all prepared samples. We have examined the photoluminescence (PL) due to defect centers and Ce 3+ ions present in prepared nanopowder which were excited at two different wavelengths. PL study revealed the effect of annealing on the emission spectra and resulted that the emission efficiency of direct excitation at λ ex = 325 nm was enhanced with respect to the indirect λ ex = 250 nm. The emission produced from CeO 2 nanocrystals dispersed in amorphous silica matrix has been influenced by many factors such as the modification of the ligand field around the Ce 3+ ions in silica, presence of hydroxyl ions and annealing temperature also. Detailed Energy transfer mechanism has been explained with all possible transition lines.
Abstract We have synthesized Cd1-xZnxO (0 ≤ x ≤ 1) nanopowder by co-precipitation method for its ... more Abstract We have synthesized Cd1-xZnxO (0 ≤ x ≤ 1) nanopowder by co-precipitation method for its comprehensive study. The Crystalline phase is changed from rocksalt CdO to wurtzite ZnO with an increase in ‘x’. The existence of H2O, COO–, CdO, and ZnO group are confirmed by FTIR. SEM analysis investigated the spherical structure for x = 0.0 & 0.2 and flakes morphology for x = 0.4 & 0.6 and hexagonal block structure for x = 0.8 & 1.0. UV–Vis spectroscopy insured the increasing trend in bandgap energy within the range 2.5 ≤ Eg ≤ 3.5 eV. PL results revealed a blue shift in excitonic and band edge emission. Methyl blue dye is being selected for decomposition using different samples of Cd1-xZnxO (0 ≤ x ≤ 1) nanopowder. It is found that sample with x = 0.8 has the highest catalytic efficiency under UV light. Moreover, higher efficiency of the ternary system is managed by its highly crystalline structure, less microstrain, large surface/volume ratio, and optical bandgap.
Silver-doped zirconia nanoparticles/thin films with different doping concentrations 0.03, 0.05 an... more Silver-doped zirconia nanoparticles/thin films with different doping concentrations 0.03, 0.05 and 0.07 mol% were synthesized by sol-gel route followed by spin coating. Zirconium (IV) chloride and silver nitrate were used as precursors. The prepared powdered samples and thin films were annealed in a programmable furnace at 650°C for 3 h. XRD spectra showed prominent tetragonal phase of zirconia and cubic phase of silver nanoparticles. Structural parameters such as crystallite size, lattice constants, micro-strain, dislocation density, specific surface area and the number of unit cell in a particle were evaluated. FTIR spectra confirmed the expected functional groups present in the annealed samples. Optical absorption spectra of Ag-doped ZrO 2 thin films established the tuning of band-gap with dopant concentration. PL spectra exhibited two broad blue emission bands centered at *340 and 475 nm. TG-DTA thermal analysis of as-prepared sample was also carried out.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
h i g h l i g h t s " In this article we are reporting the single crystal growth of L-lysine acet... more h i g h l i g h t s " In this article we are reporting the single crystal growth of L-lysine acetate. " The sated material is grown by Slow Evaporation Solution growth Technique (SEST). " To the best of our knowledge there is no report is available in the literature. " It is a potential material for NLO devices.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2012
Nonlinear optical single crystals are getting attention because of its enormous applications in t... more Nonlinear optical single crystals are getting attention because of its enormous applications in the area of fiber optic communication and optical signal processing. In this article, we are reporting the single crystal growth of l-lysine monohydrochloride by slow evaporation solution growth technique, by using double distilled water as the solvent. We found that the grown single crystal is bulk in size and fairly transparent. But after a period of time, due to its hygroscopic nature, the transparency is completely vanished and became opaque. Then we have attempted to coat the poly methyl methacrylate (PMMA) polymer on the surface of l-lysine monohydrochloride (l-LMHCL) single crystal by dip coating method. This polymer coating is giving resistance to hygroscopic nature and also acting as thin protective covering layer without affecting the other properties. Then we have systematically studied the different properties of bare, polymer coated and hygroscopic l-LMCHL single crystals. Its crystalline perfection was examined by high resolution X-ray diffractometer and found major differences in crystalline quality. Its structural and optical behavior was assessed by powder X-ray diffraction, UV-vis and luminescence analyses.
... Kumar Naik Corresponding Author Contact Information , a , E-mail The Corresponding Author , S... more ... Kumar Naik Corresponding Author Contact Information , a , E-mail The Corresponding Author , Shashi Saijpaul a and Neelam Rani a. ... Abbreviations: ADF, acid detergent fiber expressed inclusive of residual ash; aNDF, neutral detergent fiber assayed with heat stable amylase ...
The present study attempts to investigate whether differences in the quality of firm level corpor... more The present study attempts to investigate whether differences in the quality of firm level corporate governance influence short-term performance of acquiring firms for a sample of companies by creating a corporate governance index. The study is based on a survey of sample of 155 companies having completed mergers and acquisitions deals announced during January 2003 to December 2008. We document a positive relationship between corporate governance score and short-term abnormal returns by constructing broad corporate governance Index (CGI) for Indian public listed companies. We use a broad, multifactor corporate governance score, which is based on the responses to objective survey questions supplemented with interviews of senior management, directors, CFOs, board members, company secretaries, compliance officers, and investor relation officers. The questionnaire is designed on the basis of major standard qualities relevant to measure the corporate governance. The present study concludes that companies with higher rank for corporate governance score have better short-term performance which is revealed from positive and higher abnormal returns during the event windows.
Rapid advances in nanotechnology have led to its emergence as a tool for the development of green... more Rapid advances in nanotechnology have led to its emergence as a tool for the development of green synthesized noble metal nanoparticles, especially silver nanoparticles (AgNPs), for applications in diverse fields such as human health, the environment and industry. The importance of AgNPs is because of their unique physicochemical and antimicrobial properties, with a myriad of activities that are applicable in various fields, including the pharmaceutical industry. Countries with high biodiversity require the collection and transformation of information about biological assets into processes, associations, methods and tools that must be combined with the sustainable utilization of biological diversity. Therefore, this review paper discusses the applicable studies of the biosynthesis of AgNPs and their antimicrobial activities towards microorganisms in different areas viz. medicine and agriculture. The confirmed antiviral properties of AgNPs promote their applicability for SARS-CoV-2 t...
Abstract Pure and Cu/Mn-doped Cd0.4Zn0.6O (0 ≤ x ≤ 1) ternary alloy is prepared by co-precipitati... more Abstract Pure and Cu/Mn-doped Cd0.4Zn0.6O (0 ≤ x ≤ 1) ternary alloy is prepared by co-precipitation and further the variation of dopant concentration has been studied. The diffractogram of the undoped sample has peaks of both rocksalt (RS) CdO and wurtzite (WZ) ZnO phase. The individual and simultaneous doping of Cu and Mn elements has significantly altered the intensity, FWHM, and developments of defect states in Cd0.4Zn0.6O alloy. TEM microscope has investigated the crystalline size and interplanar spacing that is slightly decreased with dopant concentration which lies within the range ~ 38–30 nm. UV–Vis spectroscopy analyzed a decreasing trend in bandgap energy with dopant concentration. IN PL, the near band edge and deep trap state emission is observed at 382, 417, 448, 520 and 580 nm wavelengths. The resistivity, carrier concentration, and mobility are also computed which proposed that Cu/Mn-doped Cd0.4Zn0.6O alloy could be the better TCO with new opportunities for material science researchers.
Ceria (CeO 2) nanocrystals dispersed in silica were prepared by sol-gel, a very suitable method f... more Ceria (CeO 2) nanocrystals dispersed in silica were prepared by sol-gel, a very suitable method for large-scale production. The formation of cubic fluorite structure of CeO 2 nanocrystals was confirmed by XRD, TG-DTA and TEM. The average nanocrystalline size has been calculated~3-5 nm using Debye-Scherrer formula for different annealed samples. The calculated nanocrystalline sizes were compared with W-H plot and TEM histograms. Different structural parameters like microstrain, lattice constant, dislocation density, X-ray density and activation energy were also calculated for all prepared samples. We have examined the photoluminescence (PL) due to defect centers and Ce 3+ ions present in prepared nanopowder which were excited at two different wavelengths. PL study revealed the effect of annealing on the emission spectra and resulted that the emission efficiency of direct excitation at λ ex = 325 nm was enhanced with respect to the indirect λ ex = 250 nm. The emission produced from CeO 2 nanocrystals dispersed in amorphous silica matrix has been influenced by many factors such as the modification of the ligand field around the Ce 3+ ions in silica, presence of hydroxyl ions and annealing temperature also. Detailed Energy transfer mechanism has been explained with all possible transition lines.
Abstract We have synthesized Cd1-xZnxO (0 ≤ x ≤ 1) nanopowder by co-precipitation method for its ... more Abstract We have synthesized Cd1-xZnxO (0 ≤ x ≤ 1) nanopowder by co-precipitation method for its comprehensive study. The Crystalline phase is changed from rocksalt CdO to wurtzite ZnO with an increase in ‘x’. The existence of H2O, COO–, CdO, and ZnO group are confirmed by FTIR. SEM analysis investigated the spherical structure for x = 0.0 & 0.2 and flakes morphology for x = 0.4 & 0.6 and hexagonal block structure for x = 0.8 & 1.0. UV–Vis spectroscopy insured the increasing trend in bandgap energy within the range 2.5 ≤ Eg ≤ 3.5 eV. PL results revealed a blue shift in excitonic and band edge emission. Methyl blue dye is being selected for decomposition using different samples of Cd1-xZnxO (0 ≤ x ≤ 1) nanopowder. It is found that sample with x = 0.8 has the highest catalytic efficiency under UV light. Moreover, higher efficiency of the ternary system is managed by its highly crystalline structure, less microstrain, large surface/volume ratio, and optical bandgap.
Silver-doped zirconia nanoparticles/thin films with different doping concentrations 0.03, 0.05 an... more Silver-doped zirconia nanoparticles/thin films with different doping concentrations 0.03, 0.05 and 0.07 mol% were synthesized by sol-gel route followed by spin coating. Zirconium (IV) chloride and silver nitrate were used as precursors. The prepared powdered samples and thin films were annealed in a programmable furnace at 650°C for 3 h. XRD spectra showed prominent tetragonal phase of zirconia and cubic phase of silver nanoparticles. Structural parameters such as crystallite size, lattice constants, micro-strain, dislocation density, specific surface area and the number of unit cell in a particle were evaluated. FTIR spectra confirmed the expected functional groups present in the annealed samples. Optical absorption spectra of Ag-doped ZrO 2 thin films established the tuning of band-gap with dopant concentration. PL spectra exhibited two broad blue emission bands centered at *340 and 475 nm. TG-DTA thermal analysis of as-prepared sample was also carried out.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2013
h i g h l i g h t s " In this article we are reporting the single crystal growth of L-lysine acet... more h i g h l i g h t s " In this article we are reporting the single crystal growth of L-lysine acetate. " The sated material is grown by Slow Evaporation Solution growth Technique (SEST). " To the best of our knowledge there is no report is available in the literature. " It is a potential material for NLO devices.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2012
Nonlinear optical single crystals are getting attention because of its enormous applications in t... more Nonlinear optical single crystals are getting attention because of its enormous applications in the area of fiber optic communication and optical signal processing. In this article, we are reporting the single crystal growth of l-lysine monohydrochloride by slow evaporation solution growth technique, by using double distilled water as the solvent. We found that the grown single crystal is bulk in size and fairly transparent. But after a period of time, due to its hygroscopic nature, the transparency is completely vanished and became opaque. Then we have attempted to coat the poly methyl methacrylate (PMMA) polymer on the surface of l-lysine monohydrochloride (l-LMHCL) single crystal by dip coating method. This polymer coating is giving resistance to hygroscopic nature and also acting as thin protective covering layer without affecting the other properties. Then we have systematically studied the different properties of bare, polymer coated and hygroscopic l-LMCHL single crystals. Its crystalline perfection was examined by high resolution X-ray diffractometer and found major differences in crystalline quality. Its structural and optical behavior was assessed by powder X-ray diffraction, UV-vis and luminescence analyses.
... Kumar Naik Corresponding Author Contact Information , a , E-mail The Corresponding Author , S... more ... Kumar Naik Corresponding Author Contact Information , a , E-mail The Corresponding Author , Shashi Saijpaul a and Neelam Rani a. ... Abbreviations: ADF, acid detergent fiber expressed inclusive of residual ash; aNDF, neutral detergent fiber assayed with heat stable amylase ...
The present study attempts to investigate whether differences in the quality of firm level corpor... more The present study attempts to investigate whether differences in the quality of firm level corporate governance influence short-term performance of acquiring firms for a sample of companies by creating a corporate governance index. The study is based on a survey of sample of 155 companies having completed mergers and acquisitions deals announced during January 2003 to December 2008. We document a positive relationship between corporate governance score and short-term abnormal returns by constructing broad corporate governance Index (CGI) for Indian public listed companies. We use a broad, multifactor corporate governance score, which is based on the responses to objective survey questions supplemented with interviews of senior management, directors, CFOs, board members, company secretaries, compliance officers, and investor relation officers. The questionnaire is designed on the basis of major standard qualities relevant to measure the corporate governance. The present study concludes that companies with higher rank for corporate governance score have better short-term performance which is revealed from positive and higher abnormal returns during the event windows.
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