scholarly journals Mechanochemical synthesis and electrical conductivity of nanocrystalline δ-Bi2O3 stabilized by HfO2 and ZrO2

2009 ◽  
Vol 74 (12) ◽  
pp. 1401-1411 ◽  
Author(s):  
Miodrag Zdujic ◽  
Dejan Poleti ◽  
Cedomir Jovalekic ◽  
Ljiljana Karanovic
Keyword(s):  
Electrical Conductivity ◽  
Zirconium Oxide ◽  
Molar Ratio ◽  
Mechanochemical Reaction ◽  
Dsc Analysis ◽  
X Ray ◽  
Fluorite Type ◽  
Milling Medium ◽  
20 Nm ◽  
Milling Tools

A powder mixture of ?-Bi2O3 and HfO2, in the molar ratio 2:3, was mechanochemically treated in a planetary ball mill under air, using zirconium oxide vials and balls as the milling medium. After 50 h of milling, the mechanochemical reaction led to the formation of a nanocrystalline ?-Bi2O3 phase (fluorite-type solid solution Bi0.78Hf0.59Zr0.63O3.61), with a crystallite size of 20 nm. The mechanochemical reaction started at a very beginning of milling accompanied by an accumulation of ZrO2 arising from the milling tools. The samples prepared after various milling times were characterized by X-ray powder diffraction and DSC analysis. The electrical properties of the as-milled and pressed Bi0.78Hf0.59Zr0.63O3.61 powder were studied using impedance spectroscopy in the temperature range from 100 to 700?C under air. The electrical conductivity was determined to be 9.43?10-6 and 0.080 S cm-1 for the temperatures of 300 and 700?C, respectively.

Low-temperature route to nanoscale P3N5 hollow spheres

2003 ◽  
Vol 18 (10) ◽  
pp. 2359-2363 ◽  
Author(s):  
Hongzhou Gu ◽  
Yunle Gu ◽  
Zhefeng Li ◽  
Yongcheng Ying ◽  
Yitai Qian
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hollow Spheres ◽  
Molar Ratio ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Influence Of Temperature On ◽  
Wide Gap ◽  
20 Nm ◽  
High Degree

Nanoscale hollow spheres of amorphous phosphorus nitride (P3N5) were synthesized by reacting PCl3 with NaN3 at 150–250 °C. Transmission electron microscope images show that the hollow spheres have a diameter of 150–350 nm, and the thickness of the shell is 20 nm. A very small amount of curly films were also found in the sample prepared at 150 °C. The infrared spectrum indicates a high degree of purity. X-ray photoelectron spectroscopy indicates the presence of P and N, with a molar ratio of 1:1.62 for P:N. Ultraviolet-visible absorption spectroscopy shows an absorption band at 265–315 nm. Under photoluminescent excitation at 230 nm, the P3N5 emits ultraviolet light at 305 nm. With a band gap of 4.28 eV, the products may be a wide gap semiconductor. A possible mechanism and the influence of temperature on the formation of the hollow spheres are also discussed.

Study on the Radiosensitizing Applications of Gold Nanoparticles

2016 ◽  
Vol 851 ◽  
pp. 26-30 ◽  
Author(s):  
Chang Shu Tsai ◽  
Jou Kang Hsiao
Keyword(s):  
Gold Nanoparticles ◽  
Ph Value ◽  
Trisodium Citrate ◽  
Molar Ratio ◽  
Human Breast ◽  
X Ray ◽  
Vis Spectroscopy ◽  
M Phase ◽  
Redox Method ◽  
20 Nm

Citrate-coated gold nanoparticles (AuNPs) were prepared by using redox method and its characterization was studied thoroughly. In the preparation process, the varieties of factors were examined by TEM morphology, DLS zetasizer, XPS analysis and UV-Vis spectroscopy for evaluating their qualities and stability. The experimental results obtained under optimal condition, which are 100±5°C of reaction temperature, 4.5-6.4 of the pH value, 2-10 of molar ratio between trisodium citrate and tetrachloroauric acid, respectively. The fluorescent intensities of DCFDA-stain indicate the amount of generated ROS (reactive oxygen species) by AuNPs. The cell cycle for MDA-MB-231 human breast cancer cells exhibits S-phase arrest which can prevent mitosis. The radiosensitizing effect of AuNPs with 20 nm diameter in MDA-MB-231 was investigated by RCGG values (ratio of cell numbers in the G2/M phase to the G0/G1 phase, RCGG) and its radiosensitizing efficiency was ca. 2.29 to 3.75 fold. In this study, it was found that the radiosensitizing efficiency is related to the cytotoxicity by AuNPs. After the irradiation by x-ray to cells, the enhancement value in the presence of 20 nm diameter AuNPs were 17.2% for 3 Gy and 18.9% for 7 Gy respectively. Compared to the irradiated group alone, the enhancements values were 21.8% and 19.7, respectively.

scholarly journals Using of mechanoactivation for preparation of cerium-containing solid solutions based on zircon

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 66-71
Author(s):  
V. Yu. Vinogradov ◽  
◽  
A. M. Kalinkin ◽  
V. Ya. Kuznetsov ◽  
◽  
...  
Keyword(s):  
Solid Solutions ◽  
Zirconium Oxide ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Planetary Mill ◽  
Molar Ratio ◽  
Phase Synthesis ◽  
X Ray ◽  
Cerium Content ◽  
Zircon Structure

Solid-phase synthesis of cerium-containing solid solutions based on ZrSiO4 was described. The synthesis was carried out using mechanical activation of a mixture consisting of zirconium oxide and hydrated amorphous silica with the addition of cerium oxide at a molar ratio of ZrО2:SiО2:CeО2 equal to 0.95:1.00:0.05. The mechanically activated in a centrifugal planetary mill mixture of reagents was calcined in the temperature range of 1200–1600 °C for 3 hours, which was accompanied by the essentially complete synthesis of zircon. The cerium content in the zircon structure was calculated from X-ray powder diffraction data.

scholarly journals Effect of A-Site Nonstoichiometry on Defect Chemistry and Electrical Conductivity of Undoped and Y-Doped SrZrO3

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1258 ◽  
Author(s):  
Liliya Dunyushkina ◽  
Adelya Khaliullina ◽  
Anastasia Meshcherskikh ◽  
Alexander Pankratov ◽  
Denis Osinkin
Keyword(s):  
Electrical Conductivity ◽  
Zirconium Oxide ◽  
Relaxation Times ◽  
Secondary Phase ◽  
Solubility Limit ◽  
Defect Chemistry ◽  
Total Conductivity ◽  
Strontium Zirconate ◽  
X Ray ◽  
A Site

The effect of Sr-nonstoichiometry on phase composition, microstructure, defect chemistry and electrical conductivity of SrxZrO3−δ and SrxZr0.95Y0.05O3−δ ceramics (SZx and SZYx, respectively; x = 0.94–1.02) was investigated via X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy and impedance spectroscopy followed by distribution of relaxation times analysis of impedance data. It was shown that at low Sr deficiency (x > 0.96 and 0.98 for SZx and SZYx, respectively) a solid solution of strontium vacancies in strontium zirconate crystal structure forms, whereas at higher Sr deficiency the secondary phase, zirconium oxide or yttrium zirconium oxide, is precipitated. Yttrium solubility limit in strontium zirconate was found to be close to 2 mol%. Y-doped strontium zirconates possess up to two orders of magnitude higher total conductivity than SZx samples. A-site nonstoichiometry was shown to have a significant effect on the electrical conductivity of SZx and SZYx. The highest total and bulk conductivity were observed at x = 0.98 for both systems. Increasing the conductivity with a rise in humidity indicates that proton conduction appears in the oxides in wet conditions. A defect model based on consideration of different types of point defects, such as strontium vacancies, substitutional defects and oxygen vacancies, and assumption of Y ions partitioning over Zr and Sr sites was elaborated. The proposed model consistently describes the obtained data on conductivity.

scholarly journals STUDI HANTARAN LISTRIK SENYAWA SRN+1TINO3N+1 (N = 1 DAN 2) FASA RUDDLESDEN-POPPER YANG DISINTESIS DENGAN METODE LELEHAN GARAM

2015 ◽  
Vol 8 (2) ◽  
pp. 176
Author(s):  
Yulia Eka Putri ◽  
Hamsal Yusri ◽  
Hamsal Yusri ◽  
Zulhadjri ◽  
Zulhadjri
Keyword(s):  
Electrical Conductivity ◽  
Electron Microscope ◽  
Molten Salt Method ◽  
Strontium Oxide ◽  
Oxide Compound ◽  
X Ray ◽  
Alternative Material ◽  
Lcr Meter ◽  
20 Nm ◽  
Scanning Electron

Srn+1TinO3n+1 (n = 1, 2,...n)Ruddlesden-Popper phase is a metal oxide compound with a layered structure consisting of SrTiO3 perovskite layers and strontium oxide (SrO) layers, thus this material has a potential as termoeletrik compounds that could be developed as an alternative material for renewable energy. In this study, we examine one of the 3 parameters of termoelectric properties, namely the electrical conductivity. Srn+1TinO3n+1 (n = 1 and 2)Ruddlesden-Popper phases were synthesized using molten salt method. The synthesis was carried out at 950 °C for 10 hours with a ratio of precursor and salt were 1: 0.5. Structural analysis by X-Ray Diffractometer (XRD) confirmed that all synthesized compounds formed Srn+1TinO3n+1 (n = 1, and 2) Ruddlesden-Popper phase with the characteristic peaks at 2q = 31o, 32o, and 46o. The morphology analysis by Scanning Electron Microscope (SEM) showed that the particles have plate-shaped with crystallites size were 20 nm. The electrical properties were measured using LCR meter with the highest electrical conductivity of 2.25x10-7 S / cm which showed the semiconductors behaviour.

scholarly journals Synthesis of an optical catalyst for cracking contaminating dyes in the wastewater of factories using indium oxide in nanometer and usage in agriculture

2019 ◽  
Vol 21 (4) ◽  
pp. 98-105 ◽  
Author(s):  
Ishaq F. E. Ahmed ◽  
Ahmed I. El-Shenawy ◽  
Moamen S. Refat
Keyword(s):  
Electron Microscopy ◽  
Indium Oxide ◽  
Organic Dyes ◽  
Low Cost ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
20 Nm

Abstract Herein, the photocatalytic degradation of the Congo Red (CR) and Crystal Violet (CV) dyes in an aqueous solution were discussed in the presence of an indium(III) oxide (In2O3) as optical catalyst efficiency. The caproate bidentate indium(III) precursor complex has been synthesized and well interpreted by elemental analysis, molar conductivity, Fourier transform infrared (FT-IR), UV-Vis, and thermogravimetric (TGA) with its differential thermogravimetric (DTG) studies. The microanalytical and spectroscopic assignments suggested that the associated of mononuclear complex with 1:3 molar ratio (M3+:ligand). Octahedral structure is speculated for this parent complex of the caproate anion, CH3(CH2)4COO− ligand. The In2O3 NPs with nanoscale range within 10–20 nm was synthesized by a simple, low cost and eco-friendly method using indium(III) caproate complex. Indium oxide nanoparticles were formed after calcination of precursor in static air at 600°C for 3 hrs. The structural, grain size, morphological and decolorization efficiency of the synthesized NPs were characterized using the FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM) analyses. It was worthy mentioned that the prepared In2O3 NPs showed a good photodegradation properties against CR and CV organic dyes during 90 min.

scholarly journals Structural, spectral and thermal properties of 2,2’-iminodipyridinium(+) trihydrogen pyromellitate

2014 ◽  
Vol 79 (6) ◽  
pp. 637-648
Author(s):  
Dejan Poleti ◽  
Jelena Rogan ◽  
Lidija Radovanovic ◽  
Marko Rodic
Keyword(s):  
Structure Determination ◽  
Bond Order ◽  
Thin Layers ◽  
Molar Ratio ◽  
Dsc Analysis ◽  
X Ray ◽  
Ft Ir ◽  
Intramolecular Hydrogen ◽  
Linear Proton ◽  
Ft Ir Spectroscopy

The title compound, (Hdipya)(H3pyr), where Hdipya is protonated 2,2?-dipyridilamine and H3pyr is monoanion of pyromellytic acid (H4pyr), was obtained from the reaction mixture containing Zn(II) ions, dipya, Na4pyr (the molar ratio 2 : 2 : 1) and HNO3. The products (micro- and single-crystalline) were characterized by X-ray structure determination, FT-IR spectroscopy and TG/DSC analysis. The most striking structural feature of (Hdipya)(H3pyr) are short inter- and extremely short intramolecular hydrogen bonds. These bonds mutually connect cations and anions making thin layers parallel to the crystallographic (223) plane. Also, quite unusual, linear proton-bound polymeric {H(H2pyr)-}n anions were identified in the structure. The results of crystal structure determination are compared with FT-IR and TG/DSC data. The low position of nas(COO) vibration at 1660 cm-1 is in accordance with strong hydrogen bonding. This value can be used as a measure of C=O bond order, which is calculated to be 1.81.

Removing Substrate Background in TEM Microanalysis

1974 ◽  
Vol 32 ◽  
pp. 568-569
Author(s):  
John C. Russ ◽  
Nicholas C. Barbi
Keyword(s):  
Electrical Conductivity ◽  
Rapid Growth ◽  
Organic Film ◽  
Absolute Concentration ◽  
Background Signal ◽  
X Ray ◽  
Elemental Concentrations ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
The Continuum

The rapid growth of interest in attaching energy-dispersive x-ray analysis systems to transmission electron microscopes has centered largely on microanalysis of biological specimens. These are frequently either embedded in plastic or supported by an organic film, which is of great importance as regards stability under the beam since it provides thermal and electrical conductivity from the specimen to the grid.Unfortunately, the supporting medium also produces continuum x-radiation or Bremsstrahlung, which is added to the x-ray spectrum from the sample. It is not difficult to separate the characteristic peaks from the elements in the specimen from the total continuum background, but sometimes it is also necessary to separate the continuum due to the sample from that due to the support. For instance, it is possible to compute relative elemental concentrations in the sample, without standards, based on the relative net characteristic elemental intensities without regard to background; but to calculate absolute concentration, it is necessary to use the background signal itself as a measure of the total excited specimen mass.

Macromolecular structures of biological specimens are not obscured by controlled osmium impregnation

1983 ◽  
Vol 41 ◽  
pp. 606-607
Author(s):  
Klaus-Ruediger Peters ◽  
Samuel A. Green
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Critical Point ◽  
Metal Films ◽  
High Magnification ◽  
Osmium Impregnation ◽  
Instrumental Resolution ◽  
20 Nm ◽  
Continuous Metal

High magnification imaging of macromolecules on metal coated biological specimens is limited only by wet preparation procedures since recently obtained instrumental resolution allows visualization of topographic structures as smal l as 1-2 nm. Details of such dimensions may be visualized if continuous metal films with a thickness of 2 nm or less are applied. Such thin films give sufficient contrast in TEM as well as in SEM (SE-I image mode). The requisite increase in electrical conductivity for SEM of biological specimens is achieved through the use of ligand mediated wet osmiuum impregnation of the specimen before critical point (CP) drying. A commonly used ligand is thiocarbohvdrazide (TCH), first introduced to TEM for en block staining of lipids and glvcomacromolecules with osmium black. Now TCH is also used for SEM. However, after ligand mediated osinification nonspecific osmium black precipitates were often found obscuring surface details with large diffuse aggregates or with dense particular deposits, 2-20 nm in size. Thus, only low magnification work was considered possible after TCH appl ication.

The effect of Tin additionon on Structural and magnetic properties of the stannoferrite Li0.5+0.5XFe2.5-1.5XSnXO4

2016 ◽  
Vol 12 (3) ◽  
pp. 4307-4321 ◽  
Author(s):  
Ahmed Hassan Ibrahim ◽  
Yehia Abbas
Keyword(s):  
Particle Size ◽  
Fine Particles ◽  
Magnetic Moments ◽  
Lithium Ferrite ◽  
Tem Analysis ◽  
Weiss Temperature ◽  
X Ray ◽  
Two Phases ◽  
Nanocrystalline Ferrite ◽  
20 Nm

The physical properties of ferrites are verysensitive to microstructure, which in turn critically dependson the manufacturing process.Nanocrystalline Lithium Stannoferrite system Li0.5+0.5XFe2.5-1.5XSnXO4,X= (0, 0.2, 0.4, 0.6, 0.8 and 1.0) fine particles were successfully prepared by double sintering ceramic technique at pre-sintering temperature of 500oC for 3 h andthepre-sintered material was crushed and sintered finally in air at 1000oC.The structural and microstructural evolutions of the nanophase have been studied using X-ray powder diffraction (XRD) and the Rietveld method.The refinement results showed that the nanocrystalline ferrite has a two phases of ordered and disordered phases for polymorphous lithium Stannoferrite.The particle size of as obtained samples were found to be ~20 nm through TEM that increases up to ~ 85 nmand isdependent on the annealing temperature. TEM micrograph reveals that the grains of sample are spherical in shape. (TEM) analysis confirmed the X-ray results.The particle size of stannic substituted lithium ferrite fine particle obtained from the XRD using Scherrer equation.Magneticmeasurements obtained from lake shore’s vibrating sample magnetometer (VSM), saturation magnetization ofordered LiFe5O8 was found to be (57.829 emu/g) which was lower than disordered LiFe5O8(62.848 emu/g).Theinterplay between superexchange interactions of Fe3+ ions at A and B sublattices gives rise to ferrimagnetic ordering of magnetic moments,with a high Curie-Weiss temperature (TCW ~ 900 K).

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