scholarly journals Synthesis of CdS Nanocrystals by Employing the By-Products of the Anaerobic Respiratory Process ofDesulfovibrio alaskensis6SR Bacteria

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
L. G. Rangel-Chávez ◽  
M. I. Neria-González ◽  
A. Márquez-Herrera ◽  
M. Zapata-Torres ◽  
E. Campos-González ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Structural Quality ◽  
Cds Nanoparticles ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Transmission Microscopy ◽  
Cds Nanocrystals ◽  
Low Concentrations ◽  
Electron Transmission Microscopy ◽  
By Products

A novel methodology for the direct synthesis of CdS nanoparticles, using a biological agent that avoids the extracellular processing, and the results of the characterization of CdS nanocrystals are presented. The by-products of the anaerobic respiratory process ofDesulfovibrio alaskensis6SR along with aqueous solutions of Cd salts were successfully employed to produce CdS nanocrystals with mixed cubic and hexagonal phases. Nanocrystal size has a narrow size distribution with little dependence on the Cd concentration. Both the presence of the crystallographic cubic phase and the crystalline order decrease as Cd concentration increases. The band gap values obtained from optical transmission measurements are lower than those of the bulk crystal. Raman spectroscopy characterization agrees with electron transmission microscopy images and X-ray diffraction results indicating that the method promotes the formation of high structural quality nanocrystals when low concentrations of the Cd salt are used.

X-ray diffraction study of oxygen-conducting compoundsLn2Mo2O9(Ln= La, Pr)

2014 ◽  
Vol 70 (4) ◽  
pp. 669-675 ◽  
Author(s):  
Alexander M. Antipin ◽  
Olga A. Alekseeva ◽  
Natalia I. Sorokina ◽  
Alexandra N. Kuskova ◽  
Michail Yu. Presniakov ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Ion Migration ◽  
Transmission Microscopy ◽  
Coordination Environment ◽  
X Ray ◽  
Oxygen Ions ◽  
Oxygen Ion ◽  
Oxygen Ion Migration

The La2Mo2O9(LM) and Pr2Mo2O9(PM) single crystals are studied using precision X-ray diffraction and high-resolution transmission microscopy at room temperature. The crystal structures are determined in the space groupP213. La and Pr atoms, as well as Mo1 and O1 atoms, are located in the vicinity of the threefold axes rather than on the axes as in the high-temperature cubic phase. In both structures studied, the O2 and O3 positions are partially occupied. The coexistence of different configurations of the Mo coordination environment facilitates the oxygen-ion migration in the structure. Based on the X-ray data, the activation energies of O atoms are calculated and the migration paths of oxygen ions in the structures are analysed. The conductivity of PM crystals is close to that of LM crystals. The O2 and O3 atoms are the main contributors to the ion conductivity of LM and PM.

Polymer Stabilized Undoped and Copper Doped Cadmium Sulphide Nanoparticles: Polymer Crosslinked, Optical, and Thermal Stability

2014 ◽  
Vol 492 ◽  
pp. 291-296
Author(s):  
Arup Ratan Mandal ◽  
Sergey Volchematiev ◽  
Denis Leybo ◽  
Dmitry Muratov ◽  
Denis V. Kuznetsov
Keyword(s):  
Thermal Stability ◽  
Cadmium Sulphide ◽  
Cds Nanoparticles ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Chemical Technique ◽  
Band Transition ◽  
Wet Chemical Technique ◽  
Polymer Stabilized

Cadmium sulfide (CdS) nanoparticles synthesized by utilization of wet chemical technique are grown in polyvinyl alcohol (PVA) matrix. X-ray diffraction (XRD) pattern shows the typical inter-planar spacing corresponding to the cubic phase of CdS. High-resolution transmission electron microscopy (HRTEM) studies show the nanoparticles formation with diameter around 11 nm. Particle size is further determined by dynamic light scattering (DLS) measurement. The polymerization of PVA is confirmed by fourier transform infrared (FTIR) spectroscopy of CdS nanoparticles. UV-visible optical spectroscopy study shows that sharp excitonic bands are largely blue shifted from the absorption onset of bulk CdS and inter band transition of copper doped samples. Thermal stability of the samples is measured by thermogravimetric (TG) analysis which is also studied in details.

SYNTHESIS AND CHARACTERIZATION OF HEXAMETHYLENE TETRAMINE (HMTA) CAPPED CdS NANOPARTICLES BY HYDROTHERMAL METHOD

2011 ◽  
Vol 10 (03) ◽  
pp. 441-445 ◽  
Author(s):  
M. KARL CHINNU ◽  
L. SARAVANAN ◽  
R. JAYAVEL ◽  
C. M. RAGHAVAN ◽  
K. VIJAI ANAND ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Cadmium Acetate ◽  
Cds Nanoparticles ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Hexamethylene Tetramine ◽  
Ft Ir ◽  
Ir Analysis ◽  
Uv Visible

Cadmium sulfide nanoparticles have been synthesized by hydrothermal method using cadmium acetate, thiosemicarbazide, and sodium hydroxide as precursors with hexamethylene tetramine as the surfactant. From the X-ray diffraction analysis, it is observed that synthesized CdS nanoparticles show cubic phase. The presence of HMTA in CdS was confirmed by FT-IR analysis. The bandgap value of CdS nanostructure has been estimated by DRS–UV-Visible spectral analysis. The formation of flower-like nanoclusters was observed using scanning electron microscopy (SEM). The application of CdS nanoparticles in photocatalytic degradation was also studied.

scholarly journals X-Ray Diffraction Study of Oxygen-Conducting Compounds Ln2Mo2O9(Ln = La, Pr)

2014 ◽  
Vol 70 (a1) ◽  
pp. C48-C48
Author(s):  
Alexander Antipin ◽  
Olga Alekseeva ◽  
Natalya Sorokina ◽  
Alexandra Kuskova ◽  
Michail Presniakov ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Crystals ◽  
Basic Research ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Oxide Systems ◽  
Transmission Microscopy ◽  
X Ray ◽  
Oxygen Conductivity ◽  
Oxygen Atoms

Lanthanum molibdate La2Mo2O9(LM) and the compounds on its basis (LAMOX) attract much attention because of the high oxygen conductivity (6x10-2Sm/cm), which were found by Lacorre group. LM has the first-order phase transition at about 5800C and two phases: low-temperature monoclinic α-phase (P21) and high-temperature β-phase (P213) [1]. In the present work single crystals Ln2Mo2O9(Ln = La, Pr) were obtained by spontaneous flux crystallization in the Ln2O3–MoO3oxide systems. The LM and PM single crystals are studied by precision X-ray diffraction and high-resolution transmission microscopy. A cubic cell with a = 7.155(1) and 7.155(1) Å was chosen for two LM samples (LM_I and LM_II, respectively). More than 90% (LM_I) and 60% (LM_II) of the reflections measured were indexed in this cell. The unit cell parameter of the PM compound is slightly shorter: a = 7.087(1) and 7.089(1) Å for the PM_I and PM_II samples, respectively. More than 90% of the reflections measured were indexed for both PM crystals. It was found that the LM_II crystal consists of two cubic components grown together; a ≍ 7.155 Å for both components. The crystal structures for two LM and two PM samples are determined in space group P213. It is found that La and Pr atoms, as well as Mo1 and O1 atoms, are located in the vicinity of 3-fold axes rather than on the axes like in the high-temperature cubic phase. In both structures, the O2 and O3 positions are partially occupied. The coexistence of different configurations of the Mo coordination environment facilitates the oxygen ion migration in the structure. Based on the X-ray data, activation energies of oxygen atoms are calculated and migration paths of oxygen ions in the structures are analyzed. The conductivity of PM crystals is close to that of LM crystals. Oxygen atoms O2 and O3 make main contributions to ion conductivity of LM and PM. This study was supported in part by part by the Russian Foundation for Basic Research (project no. 14-02-00531).

scholarly journals Magnetic Characterizations of Sol-Gel-Produced Mn-Doped ZnO

2010 ◽  
Vol 2010 ◽  
pp. 1-3 ◽  
Author(s):  
R. Asmatulu ◽  
H. Haynes ◽  
M. Shinde ◽  
Y. H. Lin ◽  
Y. Y. Chen ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Magnetic Measurements ◽  
Sol Gel ◽  
Parent Compound ◽  
Hexagonal Structure ◽  
X Ray Diffraction ◽  
Transmission Microscopy ◽  
Resolution Electron ◽  
Ferromagnetic Character ◽  
Electron Transmission Microscopy

Nanoparticles of ZnO doped with 6 at.% Mn were produced by a sol-gel method. X-ray diffraction confirms the hexagonal structure as that of the parent compound ZnO, and high-resolution electron transmission microscopy reveals a single-crystallite lattice. Magnetic measurements using a superconducting quantum interference device indicate that about one half of the Mn2+ions follow Curie's law for paramagnetism. The remaining Mn2+ions exhibit a weak ferromagnetic character, which might be induced through canted antiferromagnetic interactions.

Surface Modification of ZnO Nanoparticles

2010 ◽  
Vol 644 ◽  
pp. 61-64 ◽  
Author(s):  
Rebeca Betancourt-Galindo ◽  
M.L. Berlanga Duarte ◽  
Bertha A. Puente Urbina ◽  
Oliverio S. Rodríguez-Fernández ◽  
Saul Sánchez-Valdés
Keyword(s):  
Surface Modification ◽  
Zno Nanoparticles ◽  
Molar Ratio ◽  
Precipitation Reaction ◽  
X Ray Diffraction ◽  
Transmission Microscopy ◽  
Inorganic Particles ◽  
Chemical Hydrolysis ◽  
Electron Transmission Microscopy ◽  
Controlled Precipitation

The synthesis and surface modification of ZnO nanoparticles, achieved through a controlled precipitation reaction using NaOH as precipitating agent with a 0.2 molar ratio were studied. The surface modification was carried out through a chemical hydrolysis reaction at 80°C for 6 h, in order to promote better adhesion between inorganic particles and a polymer matrix when they were used in composite materials. Both 3-aminopropyltrimethoxysilane (APTMS) and difunctional alcohol spiroorthocarbonate (SOC DIOL) were used as modifying agents in a 0.5:1 ratio with respect to ZnO nanoparticles. According to x-ray diffraction (XRD), electron transmission microscopy with scanning modulus (STEM) and infrared spectroscopy (FTIR), the ZnO crystalline structure did not change after treatment. Surface modification was performed in order to subsequently use ZnO nanoparticles in medical antimicrobial devices.

scholarly journals The Optical Properties of Crystalline Zn3Nb2O8Nanomaterials Obtained by Hydrothermal Method

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Mihaela Birdeanu ◽  
Mirela Vaida ◽  
Eugenia Fagadar-Cosma
Keyword(s):  
Hydrothermal Method ◽  
Isopropyl Alcohol ◽  
Monoclinic Space Group ◽  
Blue Color ◽  
The Novel ◽  
X Ray Diffraction ◽  
Transmission Microscopy ◽  
X Ray ◽  
Resolution Electron ◽  
Electron Transmission Microscopy

The present study is focused on the obtaining of the Zn3Nb2O8nanomaterial using the hydrothermal method and its characterization through different techniques. X-ray diffraction at room temperature revealed that a novel crystalline form of the nanomaterial forms at 1100°C belonging to monoclinic space group C2/c. Field-emission scanning electron microscopy evidenced the columnar morphology of the particle’s agglomeration and the high resolution electron transmission microscopy confirms the measured interplanar distances calculated from the X-ray diffraction experiments. Using the UV-VIS spectrum and Kubelka-Munk equations, the absorbance and the band gap for the Zn3Nb2O8nanomaterial were calculated. PL spectrum reveals a single peak at 465 nm corresponding to the blue color fluorescence. The novel crystalline nanomaterial might find applications in fluorescence covering of technical devices, due to its capacity to preserve blue fluorescence both in acrylic based paint and after embedding in isopropyl alcohol.

Ultrastructure of Melanin Formation in Curvularia sp., Alternaria sp., and Drechslera Sorokiniana

1977 ◽  
Vol 35 ◽  
pp. 398-399
Author(s):  
M. H. Wheeler ◽  
W. J. Tolmsoff ◽  
A. A. Bell
Keyword(s):  
Potassium Phosphate ◽  
Thielaviopsis Basicola ◽  
Wild Type ◽  
Potassium Phosphate Buffer ◽  
Transmission Microscopy ◽  
Electron Transmission ◽  
Melanin Formation ◽  
Before And After ◽  
Alternaria Sp ◽  
Electron Transmission Microscopy

(+)-Scytalone [3,4-dihydro-3,6,8-trihydroxy-l-(2Hj-naphthalenone] and 1,8-di- hydroxynaphthalene (DHN) have been proposed as intermediates of melanin synthesis in the fungi Verticillium dahliae (1, 2, 3, 4) and Thielaviopsis basicola (4, 5). Scytalone is enzymatically dehydrated by V. dahliae to 1,3,8-trihydroxynaphthalene which is then reduced to (-)-vermelone [(-)-3,4- dihydro-3,8-dihydroxy-1(2H)-naphthalenone]. Vermelone is subsequently dehydrated to DHN which is enzymatically polymerized to melanin.Melanin formation in Curvularia sp., Alternaria sp., and Drechslera soro- kiniana was examined by light and electron-transmission microscopy. Wild-type isolates of each fungus were compared with albino mutants before and after treatment with 1 mM scytalone or 0.1 mM DHN in 50 mM potassium phosphate buffer, pH 7.0. Both chemicals were converted to dark pigments in the walls of hyphae and conidia of the albino mutants. The darkened cells were similar in appearance to corresponding cells of the wild types under the light microscope.

Structural and morphological characterization of CdS nanoparticles

2020 ◽  
Vol 10 ◽  
Author(s):  
Manish Dwivedi ◽  
Vijay Tripathi ◽  
Dhruv Kumar ◽  
Dwijendra K. Gupta
Keyword(s):  
Blue Shift ◽  
Chemical Precipitation ◽  
Morphological Characterization ◽  
Precipitation Method ◽  
Cds Nanoparticles ◽  
Cubic Phase ◽  
Simple Chemical ◽  
Xrd Patterns ◽  
Average Size ◽  
Physical Tools

Aims: CdS nanoparticles are an attractive material having application in various field like as pigment in paints, biotag for bioimaging and many more optoelectronic as well as biological applications. Present study aims to synthesize and characterize the CdS nanoparticles to make it applicable in different areas Objectives: Preparation CdS nanoparticles by using simple and facile chemical methods and further physical and structural characterization using various physical tools Methods: In present work CdS nanoparticles has been synthesized by using rationally simple chemical precipitation method with some modi-fication on temperature and incubation time in existed methods. Characterizations were done by employing XRD, SEM, TEM, AFM tech-niques Results: Simple chemical method produces the CdS nanoparticles with the size about 100-200 nm in length and 5-10 nm in diameter. The SEM studies show that the CdS nanoparticles can agglomerate and form a continuous network like structure. The X-ray diffraction (XRD) measurements show the single-phase formation of CdS nanoparticles with the structure of cubic phase, and the broadening of XRD patterns indicates that the prepared samples are nanostructured. Our analysis on CdS nanoparticles by using transmission electron microscope and atomic force microscope (AFM) revealed that the nanoparticles form both spherical and nearly rod shaped with the average size applicable for biotagging. UV-Vis spectroscopic analysis reveals blue shift in the absorption peak probably caused by quantum confinement Conclusion: The observed CdS nanoparticles were appeared yellow in color. The XRD pattern of the CdS nanoparticles showed that the materials were of nanometric sized regime with a predominantly cubic phase along with the rod and round morphology. The study and char-acterization of CdS nanoparticles will bring us a new approach to understand biological problem by tagging nanoparticles with biomolecules and further suggests that the CdS nanoparticles formulate it more suitable biocompatible nanomaterial for biotagging and bioimaging

scholarly journals Transport and Dielectric Properties of Mechanosynthesized La2/3Cu3Ti4O12 Ceramics

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 313
Author(s):  
Mohamad M. Ahmad ◽  
Hicham Mahfoz Kotb ◽  
Celin Joseph ◽  
Shalendra Kumar ◽  
Adil Alshoaibi
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Boundary Conductivity ◽  
X Ray ◽  
Giant Dielectric ◽  
Mechanochemical Milling ◽  
Giant Dielectric Constant ◽  
Lower Temperature

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975–1025 °C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 ± 0.5 to 2.3 ± 0.5 μm with an increase in sintering temperature from 975 to 1025 °C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 × 103–3.4 × 103) and dielectric loss (0.09–0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.

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