scholarly journals Synthesis and Characterization of α-Fe2O3 Nanoparticles Prepared by PLD at Different Laser Energies

2021 ◽  
pp. 3901-3910
Author(s):  
Ghaith H. Jihad
Keyword(s):  
Energy Gap ◽  
Laser Energy ◽  
Quartz Substrate ◽  
Hall Effect Measurement ◽  
Pulse Laser Deposition Technique ◽  
Heating Process ◽  
Average Grain Size ◽  
Type Semiconductor ◽  
Oxide Phases

In this paper, ferric oxide nanoparticles) Fe2O3 NPs( were synthesized directly on a quartz substrate in vacuum by pulse laser deposition technique using Nd:YAG laser at different energies (171, 201,363 mJ/pulse). The slides were then heated to 700o C for 1 hour. The structural, optical, morphological, and electrical properties were studied. The optical properties indicated that the prepared thin films have an energy gap ranging from 2.28 to 2.04 eV. The XRD results showed no lattice impurities for other iron oxide phases, confirming that all particles were transformed into the α-Fe2O3 phase during the heating process. The AFM results indicated the dependence of nanoparticles size on the laser energy. As the laser energy increased, the average grain size increased from 72.6 nm to 79.02 nm. Hall effect measurement indicated that the film was an n-type semiconductor.

Characterization of Amethysts from Sukamara, Central Kalimantan, Using Laser-Induced Breakdown Spectroscopy (LIBS)

2020 ◽  
Vol 1 (2) ◽  
pp. 5-8
Author(s):  
Komang Gde Suastika, Heri Suyanto, Gunarjo, Sadiana, Darmaji
Keyword(s):  
Emission Intensity ◽  
Laser Energy ◽  
Emission Spectra ◽  
Atomic Emission ◽  
Laser Induced Breakdown Spectroscopy ◽  
Chemical Formula ◽  
Central Kalimantan ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

Abstract - Laser-Induced Breakdown Spectroscopy (LIBS) is one method of atomic emission spectroscopy using laser ablation as an energy source. This method is used to characterize the type of amethysts that originally come from Sukamara, Central Kalimantan. The result of amethyst characterization can be used as a reference for claiming the natural wealth of the amethyst. The amethyst samples are directly taken from the amethyst mining field in the District Gem Amethyst and consist of four color variations: white, black, yellow, and purple. These samples were analyzed by LIBS, using laser energy of 120 mJ, delay time detection of 2 μs and accumulation of 3, with and without cleaning. The purpose of this study is to determine emission spectra characteristics, contained elements, and physical characteristics of each amethyst sample. The spectra show that the amethyst samples contain some elements such as Al, Ca, K, Fe, Gd, Ba, Si, Be, H, O, N, Cl and Pu with various emission intensities. The value of emission intensity corresponds to concentration of element in the sample. Hence, the characteristics of the amethysts are based on their concentration value. The element with the highest concentration in all samples is Si, which is related to the chemical formula of SiO2. The element with the lowest concentration in all samples is Ca that is found in black and yellow amethysts. The emission intensity of Fe element can distinguish between white, purple, and yellow amethyst. If Fe emission intensity is very low, it indicates yellow sample. Thus, we may conclude that LIBS is a method that can be used to characterize the amethyst samples.Key words: amethyst, impurity, laser-induced, breakdown spectroscopy, characteristic, gemstones

Comparative Characterization of Different Samples Containing Nano-ZnO Particles with Applicability in Topical Therapies

2019 ◽  
Vol 56 (3) ◽  
pp. 652-656
Author(s):  
Raul Chioibas ◽  
Florin Borcan ◽  
Ovidiu Mederle ◽  
Dana Stoian ◽  
Codruta Marinela Soica
Keyword(s):  
Synthesis Method ◽  
Pharmaceutical Preparations ◽  
Ultrasound Treatment ◽  
Heating Process ◽  
White Pigment ◽  
Nano Zno ◽  
Zno Particles ◽  
Repeated Freezing ◽  
Skin Healing

Zinc oxide (ZnO) is an inorganic compound used for its antiseptic and skin healing properties. It is an excellent protective filter against UV radiation and it can be used as white pigment in pharmaceutical preparations. In this study, nano-ZnO particles were obtained by ultrasound treatment, and respectively by repeated freezing/heating process. The influence of synthesis method and of ultrasound generator parameters on the particles size and stability was observed. The results reveal that were obtained samples with a very good stability and sizes between 15 and 96 nm. It was found that synthesis based on ultrasound treatment lead to the formation of nanoparticles with lower sizes.

pH Influences on Optical Absorption of Anthocyanin from Black Rice as Sensitizer for Dye Sensitized Solar Cell TiO2 Nanoparticles

2016 ◽  
Vol 864 ◽  
pp. 154-158
Author(s):  
Mariya Al Qibtiya ◽  
Eka Cahya Prima ◽  
Brian Yuliarto ◽  
Suyatman
Keyword(s):  
Solar Cell ◽  
Optical Absorption ◽  
Dye Sensitized Solar Cell ◽  
Black Rice ◽  
X Ray ◽  
Dye Sensitized ◽  
Current Voltage ◽  
Average Grain Size ◽  
Uv Visible

Natural dyes extracted from black rice are used as sensitizer for dye sensitized solar cell. The anthocyanin extracted with various pH in acidic and neutral coditions. Preparation of fotolectrode TiO2 film using doctor blade method and resulting average grain size 33,9 nm using X-Ray Diffractometer. Characterization of morphology and cross-section film TiO2 is confirmed by Scanning Electron microscopy (SEM). Optical absorption using UV-Visible Spectroscopy to obtain spectrum absorbance of anthocyanin in various pH. The current-voltage (J-V) characterization shows the performance DSSC have a match relation to the optical absorption. The best absorption of anthocyanin obtained at pH 6 as well as conversion efficiency reaches 2.26% at this pH condition.

Fabrication/Characterization of a Pseudomorphic Ga0.1In0.9P/InP MESFET

1993 ◽  
Vol 300 ◽  
Author(s):  
M. S. Feng ◽  
Y. M. Hsin ◽  
C. H. Wu
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Energy Gap ◽  
Chemical Vapor ◽  
Drain Current ◽  
Low Pressure ◽  
Inp Substrate ◽  
Metalorganic Chemical

ABSTRACTA pseudomorphic Ga0.1In0.9P/InP MESFET grown by low pressure metalorganic chemical vapor deposition(LP-MOCVD) has been fabricated and characterized. The results indicated a transconductance of 66.7 ms/mm and a saturation drain current (Idss) of 55.6 mA have been achieved; furthermore, the Schottky barrier on InGaP as high as 0.67eV can be obtained using Pt2Si as the gate material. For comparison, a conventional InP MESFET with 5μm gate length has also been fabricated on InP epitaxial layer grown by low pressure metalorganic chemical vapor deposition on Fe-doped semi-insulating InP substrate. The transconductance and Idss were found to be 46.7 mS/mm and 43.1 mA at zero gate, respectively, for the depletion mode n-channel MESFET with Au as the gate metal; whereas, for the MESFET using Pt2Si as the gate metal, a transconductance of 40.3 mS/mm and a saturation drain current of 41.1 mA at zero gate bias have been obtained. The results indicated that Ga0.1In0.9P/lnP MESFET has better performance than InP MESFET because of higher energy gap of Ga0.1In0.9P.

scholarly journals Sodium Titanate Synthesis For The Photocatalytic Degradation of NO

2021 ◽  
Author(s):  
Marco Antonio Cueto Bastida ◽  
Yadira Guadalupe Maldonado ◽  
Yolanda Reyes Vidal ◽  
Myriam Solis Lopez ◽  
Eduardo Coutino Gonzalez ◽  
...  
Keyword(s):  
Flow Rate ◽  
Sodium Titanate ◽  
Photocatalytic Reduction ◽  
Mass Ratio ◽  
Hydrothermal Route ◽  
Reduction Of No ◽  
Oxide Phases ◽  
Photocatalytic Reduction Of No

Abstract The synthesis and characterization of sodium titanates (ST) and its evaluation in the photocatalytic reduction of nitric oxide (NO) is described in this contribution. The materials were synthesized by an hydrothermal route using the following parameters; 5 M NaOH concentration used as TiO2 mineralizer agent, under 170 °C for 48 hours, and a dose of TiO2 of 0.06 mg/mL (expressed as the mass ratio of TiO2/mL with respect to NaOH); resulting in tri- and hexa- ST. A nanotubular morphology was observed for the ST as proved by scanning electron microscopy (SEM) and a subsequent heat-treatment at 400 °C allowed a complete transformation of tri- to hexa- sodium titanates to modify the bandgap. The obtained ST were impregnated with Ag+ and Zn+ cations, respectively (ST-Ag, ST-Zn), to tune the bandgap of the materials. XPS analysis of the ST-Ag materials showed evidence of metallic Ag pointing to the formation of silver nanoparticles, whereas for ST-Zn oxide phases were mainly spotted. The materials were evaluated for the photocatalytic reduction of NO using a reactor fed with a continuous flow rate of NO, generated in situ, at a flow rate of 280 ml/min using nitrogen and a 253 nm wavelength UV irradiation source. The photocatalytic tests showed that pristine ST (tri and hexa-titanate) was the photocatalyst that displayed the best performance in the reduction of NO with respect to the impregnated samples (ST-Ag, ST-Zn). Maximum efficiencies of 80% degradation were reached when using 1 g of photocatalyst with a flow of 280 ml/min and a lamp of 253 nm.

SnO2 Nano/Microfibers for Gas Sensors

2020 ◽  
Vol 405 ◽  
pp. 324-329
Author(s):  
Erika Mudra ◽  
Ivan Shepa ◽  
Alexandra Kovalcikova ◽  
Ondrej Milkovič ◽  
Jan Dusza
Keyword(s):  
Gas Sensors ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Band Gap Energy ◽  
Calcination Process ◽  
Sensing Applications ◽  
Amorphous Nature ◽  
Coating Method ◽  
Type Semiconductor

SnO2 is an n-type semiconductor with the band gap energy of 3.6 eV. It has been widely studied for gas sensing applications, the sensitivity of which can be easily tuned by the operating temperature. The presented paper is focused on the preparation and detailed characterization of the hollow SnO2 nano/microfibers suitable for gas detection sensors. Ceramic SnO2 fibers were produced by needleless electrospinning and followed by the calcination process. The characterization was performed by SEM, TEM, XRD, and Raman spectroscopy. The precursor PVP/SnO2 fibers had amorphous nature. The calcination of the electro spun precursor resulted in the formation of hollow crystalline fibrous structures. The formation mechanism of hollow fibers has been described. Subsequently, a homogeneous fibrous layer was created by the spin coating method for gas sensing applications.

scholarly journals Characterization of the iron oxide phases formed during the synthesis of core–shell FexOy@C nanoparticles modified with Ag

2020 ◽  
Vol 31 (39) ◽  
pp. 395703
Author(s):  
D A Petrov ◽  
C -R Lin ◽  
R D Ivantsov ◽  
S G Ovchinnikov ◽  
S M Zharkov ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Core Shell ◽  
Oxide Phases

scholarly journals A Comparative Investigation on Conventional and Stationary Shoulder Friction Stir Welding of Al-7075 Butt-Lap Structure

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1264 ◽  
Author(s):  
Yu Chen ◽  
Huaying Li ◽  
Xiaoyu Wang ◽  
Hua Ding ◽  
Fenghe Zhang
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Comparative Investigation ◽  
Flow Mode ◽  
Nugget Zone ◽  
Friction Stir ◽  
Stationary Shoulder ◽  
Average Grain Size ◽  
Al 7075

Both conventional friction stir welding (C-FSW) and stationary shoulder friction stir welding (S-FSW) were employed to join the Al-7075 butt-lap structure, then the microstructural evolution and mechanical characterization of all FSW joints were systematically studied. The C-FSW joint exhibited a rough surface with flashes and arc corrugations, while the surface of the S-FSW joint became smooth. Moreover, for the S-FSW joint, the shoulder-affected zone got eliminated and the material flow mode during FSW was changed owning to the application of stationary shoulder. Furthermore, in comparison to C-FSW, the lower welding heat input of S-FSW decreased the average grain size in the nugget zone and inhibited the coarsening of strengthening precipitates in the heat-affected zone, elevating the overall hardness for the S-FSW joint. In addition, the tensile strength of the S-FSW joint became higher compared to the C-FSW joint, and all the FSW joints failed inside the nugget zone attributing to the existence of hook defect. The sharp-angled hook defect deteriorated the plasticity of the C-FSW joint further, which was only 70% that of the S-FSW joint.

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