Effect of Crystal Size and Ag Concentration on the Thermoluminescent Response of Pure and Ag-Doped LiF Cubes

NANO ◽  
2016 ◽  
Vol 11 (04) ◽  
pp. 1650041 ◽  
Author(s):  
Miguel A. Vallejo ◽  
Modesto A. Sosa ◽  
Esteban Rivera ◽  
Juan C. Azorín ◽  
Jesús Bernal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Crystal Size ◽  
Precipitation Method ◽  
Size Distributions ◽  
Photoluminescence Spectra ◽  
X Ray ◽  
Co Precipitation ◽  
Synthesized Materials ◽  
Scanning Electron

In this paper, the co-precipitation method was used to synthesize pure and Ag-doped LiF crystals and the effect of crystalline cube sizes and Ag concentration on the thermoluminescent (TL) response is reported. The synthesized materials were characterized by scanning electron microscopy and their morphology and size distributions were determined. Crystal sizes were found to be strongly dependent on the ethanol:water ratio, varying from 4.1[Formula: see text][Formula: see text]m to 150[Formula: see text]nm for pure LiF crystals. For Ag-doped samples, the best ethanol:water ratio was found to be 9:1, giving crystals from 0.50[Formula: see text][Formula: see text]m to 1.21[Formula: see text][Formula: see text]m. A single cubic crystalline phase was determined by XRD for all synthesized samples. The photoluminescence spectra as well as UV-Vis absorbance were also analyzed. The TL response to X-ray irradiation was studied for an exposition of 43[Formula: see text]R. Two effects were observed in the TL response. The first concerns with a significant dependence of the TL intensity on the size of the crystals, being larger for the smallest crystals for pure LiF, and second, for Ag-doped samples the TL intensity augmented almost linearly with the Ag concentration.

scholarly journals Method for preventing air pollution: Methane oxidation by two types of catalysts

2014 ◽  
Vol 25 (1) ◽  
pp. 43-46
Author(s):  
Cristina Ileana Covaliu ◽  
Gina Alina Traistaru ◽  
Gigel Paraschiv
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Air Pollution ◽  
Methane Oxidation ◽  
Sol Gel ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
Scanning Electron

Abstract Methane oxidation using different catalysts is an useful process for preventing air pollution. This study presents the methane oxidation by two types of catalysts: Pd-Sn/Al2O3 and spinel mixed oxide, CuFe2O4. The Pd-Sn/Al2O3 was successfully prepared by sol-gel method and CuFe2O4 by co-precipitation method. The catalysts obtained have been characterized structurally, morphologically and texturally by X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). The catalytic activity tests regarding methane oxidation were also performed.

A Possible Nanoreactor: CaFe-L(ayered)D(ouble)H(ydroxide) with Intercalated Cinnamate Derivatives

2012 ◽  
Vol 730-732 ◽  
pp. 65-70 ◽  
Author(s):  
David Srankó ◽  
Szabolcs Muráth ◽  
Monika Sipiczki ◽  
Maria Szabó ◽  
Ákos Kukovecz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spatial Arrangement ◽  
The Other ◽  
Precipitation Method ◽  
X Ray ◽  
Host Materials ◽  
Interlayer Region ◽  
Co Precipitation ◽  
Scanning Electron

The synthesis and characterisation of various organic-inorganic nanohybrids are reported in this contribution. The host material was Ca3Fe-LDH prepared by the co-precipitation method.E-cinnamate, E-4-nitrocinnamate orE-2,5-difluorocinnamate anions were the guests. Successful intercalation occurred through the introduction of the guest anion into the interlayer region of the host materials with the dehydration-rehydration method. The obtained nanohybrids were studied by powder X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray fluorescence (EDX) coupled to the SEM instrument and infrared spectroscopy (IR). These methods were used on one hand to prove that intercalation was successful and for the characterisation of the substances on the other. Molecular modelling was used for visualising the possible spatial arrangement of the organic anions.

Synthesis of LiFePO4 Cathode Materials by a Chemical Method

2011 ◽  
Vol 675-677 ◽  
pp. 57-60
Author(s):  
Yuan Sun ◽  
Xiu Juan Zhao ◽  
Rui Ming Ren
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Method ◽  
Single Phase ◽  
Raw Materials ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
Scanning Electron

The olivine-type LiFePO4 powder was prepared by a chemical method using the synthesized FePO4⋅2H2O, LiOH and glucose as raw materials. The synthesized FePO4⋅2H2O powder was obtained by co-precipitation method. FePO4⋅2H2O and LiFePO4 powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed the synthesized FePO4⋅2H2O powder at pH of 2.05 was in a single phase and nearly spherical in shape. Using the synthesized powders to prepared LiFePO4 at 600 °C in vacuum for 2 h was nearly spherical in shape and whose size was in the range of 0.1-0.5μm.

scholarly journals A Novel Strong Cyan Luminescence Emission of Tb2O3 Particles

2021 ◽  
Author(s):  
Fatma Unal
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ammonium Carbonate ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Terbium Oxide ◽  
X Ray ◽  
Ft Ir ◽  
Pl Emission ◽  
Scanning Electron

Abstract Terbium oxide (Tb2O3) particles (NPs) were synthesized by precipitation method using ammonium carbonate as precipitation agent. Effects of precursor molarity (0.1, 0.15 and 0.2 M) on photoluminescence (PL) behaviour of the NPs were investigated. The presence of the Tb2O3 phase was confirmed by X-Ray Diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR) analyses. Morphological investigations of the produced powders were made by Field Emission Gun-Scanning Electron Microscopy (FEG-SEM). It showed that the morphology of Tb2O3 particles transformed from the nanograin chain to bundles morphology of rod-like as the amount of precursor molarity increased. Emission spectrum were investigated by Photoluminescence (PL) Spectroscopy. All the Tb2O3 particles exhibited the strongest peak at 493 nm ascribed to 5D4-7F6 (magnetic dipole (MD), C2) transition. The increase in the number of C2 sites released from the MD transition with the increase of the precursor molarity caused a negative increase in the b* (yellowness/blueness of the emission) value in the CIE diagram, indicating that the colour shifted to the blue region. The Tb2O3 particles produced by the precipitation method exhibited novel strong cyan colour and the PL emission intensity increased with increasing molarity.

scholarly journals Pengaruh Perbandingan Mol Awal Titanium dan Perak terhadap Sifat-Sifat Fisika-Kimia TiO2-tersensitifkan AgCl

2017 ◽  
pp. 106-115
Author(s):  
Isnaya Khamida Zulfah ◽  
Hari Sutrisno
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Diffuse Reflectance ◽  
Silver Chloride ◽  
Ultra Violet ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
X Ray ◽  
Initial Comparison ◽  
Scanning Electron

Titanium dioksida (TiO2)merupakan semikonduktor yang memiliki fungsi sebagai fotokatalis, sel surya, anti bakteri, anti polutan, dan anti buram. Salah satu cara untuk meningkatkan aktifitas fungsional  TiO2dengan menggeser daerah aktifitas atau energi celah pita (Eg) dari sinar ultra violet (UV) ke daerah sinar tampak melalui penambahan zat pensensitif TiO2.Pada penelitian ini, perak klorida (AgCl) digunakan sebagai zat pensensitif TiO2. Tujuan penelitian ini untuk mengetahui pengaruh variasi perbandingan mol awal [Ti8O12(H2O)24]8.Cl8.HCl.7H2O dengan AgNO3 terhadap sifat-sifat fisik TiO2 tersensitifkan AgCl (TiO2@AgCl) yang disintesis dengan metode pengendapan basah dalam suasana asam. Variasi perbandingan awal yang digunakan yaitu perbandingan mol [Ti8O12(H2O)24]8.Cl8.HCl.7H2O :mol AgNO3sebesar 1:9, 1:10, 1:11, 1:12, dan 1:13yang dilarutkan dalam pelarut etanol (total pelarut 37.5 mL). Sampel padat TiO2@AgCl dihasilkan dengan metode pengendapan basah dalam kondisi asam melalui pengontrolan asam HNO3 pada pH~1. Sampel dihasilkan dari penguapan filtrat yang  bebas dari endapan AgCl, hingga volume yang didapat setengah dari volume awal. Sampel TiO2@AgCl dikarakterisasi dengan berbagai instrumen: Difraktometer Sinar-X (XRD),Scanning Electron Microscopy-Electron Dispersive X-Ray Analyzer (SEM-EDAX), dan Spektrofotometer UV-Vis Diffuse Reflectance. Hasil penelitian menunjukkan semua sampel TiO2@AgCl berisi 1 fasa nanopartikel (nanokristalit) TiO2 dan 3 fasa kristal yaitu rutil, anatas, dan AgCl.TiO2@AgCl memiliki bentuk morfologi berupa mikrosferik dengan ukuran berkisar 0.5-1 μm. Berdasarkan hasil analisisdengan spektrofotometer UV-Vis Diffuse Reflectance menunjukkan semua sampel TiO2@AgCl mengabsorbsi sinar ultra violet (UV) dengan Eg sebesar 2.87-3.89 eV, dan sinar tampak dengan Eg sebesar 1.60-2.40 eV. Titanium dioxide (TiO2) is a semiconductor that can be applied in the field of photocatalyst, solar cell, anti-bacterial, anti-pollutants, and anti-fogging. The functional activity of TiO2 can be increased by shifting the activity area from ultraviolet (UV) to visible through the addition of sensitizer. In this research, silver chloride (AgCl) was used as a sensitizer The objective of the research is to study the effect of the initial mole comparison of [Ti8O12(H2O)24]8.Cl8.HCl.7H2O and AgNO3on the physical properties of AgCl-sensitized TiO2(TiO2@AgCl). All TiO2@AgCl were synthesized using the wet chemical precipitation method under acidic conditions by the addition of a concentrated HNO3 with pH ~ 1. The initial comparison variation used was the mole ratio of [Ti8O12(H2O)24]8.Cl8.HCl.7H2O  : AgNO3 of 1: 9, 1:10, 1:11, 1:12, and 1:13. Each of these materials was dissolved in ethanol to 37.5 ml. All samples were produced from evaporation of filtrate free from AgCl precipitate, until the volume obtained half of the initial volume. The solid samples were characterized using X-Ray Diffractometer (XRD), Scanning Electron Microscopy-Electron Dispersive X-Ray Analyzer (SEM-EDAX), and UV-Vis spectrophotometer Diffuse Reflectance.The results showed that all samples of TiO2@AgCl consisted of 1 phase of TiO2-nanoparticles and 3 phases of rutile, anatase and AgCl crystals. The morphology of TiO2@AgCl is microspheric with a size ranging from 0.5-1 μm. Based on the results of the analysis with the UV-Vis spectrophotometer Diffuse Reflectance showed that all samples of TiO2@AgCl absorb ultraviolet (UV) rays with bandgap (Eg) ranging from 2.87 to 3.89 eV, and the visible light with Eg ranges from 1.60 to 2.40 eV.

scholarly journals Obtaining hydroxyapatite with different precursors for application as a biomaterial

Cerâmica ◽  
2019 ◽  
Vol 65 (373) ◽  
pp. 99-106
Author(s):  
K. A. S. Farias ◽  
W. J. B. Sousa ◽  
M. J. B. Cardoso ◽  
R. J. S. Lima ◽  
M. A. Rodriguez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Decomposition ◽  
Fourier Transform ◽  
Calcium Oxide ◽  
Crystal Size ◽  
X Ray Diffraction ◽  
Thermal Decomposition Process ◽  
X Ray ◽  
Scanning Electron

Abstract The hydroxyapatite (HAp) is a ceramic biomaterial with wide application in the bone regeneration. It can be obtained by different routes and different precursors. In this study, the synthesis of HAp was carried out by precipitation and subsequent thermal treatment using different calcium precursors: calcium hydroxide from synthetic origin and calcium oxide obtained from the eggshell. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. By SEM, variations of the crystal size and the concentration of agglomerates were observed. FTIR and XRD analyses proved the formation of HAp and how the (mineral and biological) precursors affected the microstructure. The thermal decomposition process of the calcium oxide obtained from the eggshell showed to be more effective for the synthesis of the hydroxyapatite, resulting in more stable morphology and microstructure.

scholarly journals Influence of Processing Type in the Morphology of Membranes Obtained from PA6/MMT Nanocomposites

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Rodholfo da Silva Barbosa Ferreira ◽  
Caio Henrique do Ó Pereira ◽  
Rene Anisio da Paz ◽  
Amanda Melissa Damião Leite ◽  
Edcleide Maria Araújo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Screw Extruder ◽  
X Ray ◽  
Membrane Morphology ◽  
Twin Screw ◽  
Microscopy Images ◽  
Scanning Electron

The nanocomposites have an extensive use in the current process of membrane preparation, taking into account their unique features as membranes. Thus, the study of nanocomposite processing to obtain membranes is highly important. In this work, Brazilian clay was used (Brasgel PA) for the preparation of polyamide/clay nanocomposite. The nanocomposites were produced in a high rotation homogenizer and in a twin screw extruder. From the nanocomposites and pure polymers processed in the two equipments, membranes were prepared by the immersion-precipitation method, using formic acid as solvent. By X-ray diffraction (XRD), the formation of exfoliated and/or partially exfoliated structures with changes in the crystalline phases of the polyamide was observed. From scanning electron microscopy images, it was observed that the processing clearly influenced the membrane morphology.

Effect of EDTA on the Morphology and Size of SrCO3 Particles during Crystallization

2010 ◽  
Vol 148-149 ◽  
pp. 1551-1555
Author(s):  
Yan Hong Zhao ◽  
Qing Yue Jia ◽  
You Gao ◽  
Xiao Jing Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Acetic Acid ◽  
Spherical Shape ◽  
Strontium Carbonate ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Scanning Electron

Strontium carbonate particles with different morphologies and sizes were synthesized successfully by a precipitation method in the presence of ethylenediaminetetra-acetic acid disodium (abbreviate as EDTA) at 25 . The phase structure and morphology of these SrCO3 particles were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD results showed that orthorhombic crystalline SrCO3 particles were prepared in the absence of and presence of EDTA. It was found that this additive played an important role in controlling the morphology and size of the particles, which changed from dendritic to spherical shape as EDTA was added.

scholarly journals Supplemental Material: The products of primary magma fragmentation finally revealed by pumice agglomerates

2021 ◽  
Author(s):  
Thomas Giachetti ◽  
et al.
Keyword(s):  
Electron Microscopy ◽  
Computed Tomography ◽  
Scanning Electron Microscopy ◽  
Size Distributions ◽  
Sample Collection ◽  
X Ray ◽  
Additional Information ◽  
Magma Fragmentation ◽  
X Ray Computed ◽  
Scanning Electron

Additional information on (1) the four eruptions studied and sample collection, (2) lapilli selection, (3) measurements of volume and porosity, (4) analysis by X-Ray computed tomography and scanning electron microscopy, and (5) calculation of protopyroclasts size distributions.<br>

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