scholarly journals Electro-Thermal and Semiconductivity Behaviour of Natural Sintered Complex Carbonate Ore for Thermo-Technological Applications

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Loutfy H. Madkour
Keyword(s):  
Energy Gap ◽  
Sintering Temperature ◽  
Thermal Analyses ◽  
Charge Carriers ◽  
Degree Of Crystallinity ◽  
Power Coefficient ◽  
Free Electrons ◽  
Dc Voltage ◽  
X Ray ◽  
Main Charge

The polymetal (Zn, Pb, Fe, Ca, Mg, Cd, Ba, Ni, Ti, and SiO2) complex Umm-Gheig carbonate ore is subjected to sintering treatment at 573, 773, 973 and 1273 K respectively for four hours. Chemical, spectral, X-ray and differential thermal analyses are applied for the native ore as well as for the samples preheated and sintered. The current versus applied DC voltage (I–V) characteristics, bulk density (Db), percent shrinkage (%S), activation energy (Ea) and energy gap (Eg) are established for the sintered ore. The electrical conductivity σ, thermal conductivity (K) and thermoelectric power coefficient α have been investigated as a function of applied temperature for the sintered ore materials. The electrical conduction is mainly achieved by free electrons near or in conduction band or n-type. As the sintering temperature (Ts) increases the conduction of the ore is also increased due to the recombination process taking place between the electrons and holes. Electrons hopping between Fe2+ and Fe3+ are the main charge carriers. The formation of Fe3O4 at high sintering temperature acts as an active mineralizer, thus inducing an increased degree of crystallinity and a more ordered crystal structure is produced.

Obtaining the specified electrophysical parameters of In0,01Ga0,99As:(Zn/Si) layers of solar cells in the epitaxial process from the gas phase

2020 ◽  
Author(s):  
A.A. Lebedev ◽  
A.A. Smirnov ◽  
A.A. Naumova ◽  
N.T. Vagapova ◽  
B.V. Zhalnin
Keyword(s):  
Gas Phase ◽  
Conductivity Measurement ◽  
Charge Carrier Concentration ◽  
Charge Carriers ◽  
X Ray ◽  
Contact Conductivity ◽  
Main Charge ◽  
Distribution Uniformity ◽  
Structural Parts ◽  
Electrophysical Parameters

The paper presents the results of studying the electrophysical characteristics (conductivity and concentration of the main charge carriers) of In0.01Ga0.99As layers of the middle cascade and other structural parts of the space-based InGaP/InGaAs/Ge solar cell depending on the doping type and level specified during epitaxial growth from the gas phase by varying the supply parameters of the sources of Si and Zn impurities. The studies were performed using X-ray diffractometry, non-contact conductivity measurement, electrochemical C–V profilometry, van der Pau method (Hall effect). A linear dependence of the main charge carrier concentration in the layer on the fraction of the doping precursor in the gas mixture was confirmed. The proportionality coefficients were determined for silicon and its disilane precursor, for zinc and its dimethylzinc precursor. The results of the dopant distribution uniformity study are shown and discussed as well as the assumptions about the effects of the temperature field gradient and the stress state in the layer and substrate.

scholarly journals Synthesis and Characterizations of Barium Zirconate–Alkali Carbonate Composite Electrolytes for Intermediate Temperature Fuel Cells

2021 ◽  
Vol 5 (7) ◽  
pp. 183
Author(s):  
Gilles Taillades ◽  
Ismahan Hachemi ◽  
Paul Pers ◽  
Julian Dailly ◽  
Mathieu Marrony
Keyword(s):  
Fuel Cells ◽  
Charge Carriers ◽  
Intermediate Temperature ◽  
Interfacial Region ◽  
Barium Zirconate ◽  
Ionic Conductors ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Charge ◽  
Alkali Carbonate

Composite ionic conductors for intermediate temperature fuel cells (ITFC) were produced by a combination of yttrium-substituted barium zirconate (BaZr0.9Y0.1 O2.95, BZY) and eutectic compositions of alkali carbonates (Li2CO3, Na2CO3, and K2CO3, abbreviated L, N, K). These materials were characterized by X-ray diffraction, scanning electron microscopy, and impedance spectroscopy. The combination of BZY with alkali metal carbonate promotes the densification and enhances the ionic conductivity, which reaches 87 mS·cm−1 at 400 °C for the BZY–LNK40 composite. In addition, the increase of the conductivity as a function of hydrogen partial pressure suggests that protons are the main charge carriers. The results are interpreted in terms of the transfer of protons from the ceramic component to the carbonate phase in the interfacial region.

scholarly journals Процессы переноса заряда в легировaнном натрием углеродном композите на основе фуллеренов и терморасширенного графита

2019 ◽  
Vol 61 (10) ◽  
pp. 1971
Author(s):  
В.И. Берёзкин
Keyword(s):  
Carbon Composite ◽  
Charge Carriers ◽  
Free Electrons ◽  
Additional Increase ◽  
Undoped Material ◽  
Main Charge ◽  
Carbon Composite Material ◽  
Scattering Centers ◽  
Order Of Magnitude ◽  
Thermally Exfoliated Graphite

AbstractThe results of doping of a carbon composite material, in which fullerenes are located in a conductive matrix based on thermally exfoliated graphite, with a sodium dopant are presented. Charge transfer processes taking place in samples with different initial ratios of components are studied. It turns out that the electrical resistivity of the samples increases with the introduction of sodium and an increase in its content, since the mobility of the main charge carriers, which are holes as in the undoped material, decreases. The concentration of charge carriers in different types of samples varies in both directions and can increase by more than an order of magnitude. It is concluded that Na plays an ambiguous role. It can contribute not only to the generation of free electrons, but also to an additional increase in the concentration of various defects that can generate free holes and can affect, being effective traps and scattering centers, all types of charge carriers.

scholarly journals Synthesis and Characterizations of Doped Barium Zirconate – Alkali Carbonate Composite Electrolytes

2021 ◽  
Author(s):  
Gilles Taillades ◽  
Ismahan Hachemi ◽  
Mathieu Marrony ◽  
Julian Dailly
Keyword(s):  
Electron Microscopy ◽  
Charge Carriers ◽  
Interfacial Region ◽  
Barium Zirconate ◽  
Composite Electrolytes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Charge ◽  
Alkali Carbonate ◽  
Scanning Electron

Abstract Composite materials based on yttrium-doped zirconate (BaZr0.9Y0.1 O2.95, BZY) and eutectic compositions of alkali carbonates (Li2CO3, Na2CO3 and K2CO3) are investigated. These materials were characterized by X-ray diffraction, scanning electron microscopy and impedance spectroscopy. This study evidences that the combination of BZY with carbonate promotes the densification and enhances the ionic conductivity which reaches 87 mS.cm-1 at 400°C for the BZY – LNK40 composite. In addition, the increase of the conductivity as a function of pH2 suggests that protons are the main charge carriers. The obtained results are interpreted by the transfer of protons from the ceramic to the carbonate phase in the interfacial region.

Photocatalytic Degradation of 2-chlorophenol under γ-Bi2MoO6/Graphene Oxide

MRS Advances ◽  
2019 ◽  
Vol 5 (11) ◽  
pp. 581-589 ◽  
Author(s):  
J. Rodríguez-López ◽  
R. Rangel ◽  
P. Bartolo-Pérez ◽  
J.J. Alvarado-Gil ◽  
J. L. Cervantes-López ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Energy Gap ◽  
Physicochemical Characterization ◽  
Catalytic Performance ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
Bismuth Molybdate ◽  
X Ray

ABSTRACTThe present research was aimed to study the degradation of 2-Chlorophenol through the use of bismuth molybdate (γ-Bi2MoO6) structures supported on graphene oxide (GO) which is intended to control the recombination of charge carriers. γ-Bi2MoO6/GO systems were doped with nitrogen via chemical reaction, to reduce their energy gap, improving their photocatalytic activity. Structural and physicochemical characterization of the resulting catalysts were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis. The obtained compounds show good photo catalytic performance when using visible energy to degrade 2-Chlorophenol, obtaining 80% of degradation in 65 min.

Mineralogical, crystallographic and technological characteristics of Yaylayolu kaolin (Kütahya, Turkey)

Clay Minerals ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 397-410 ◽  
Author(s):  
G. Yanik
Keyword(s):  
Ph Value ◽  
Thermal Analyses ◽  
Drying Shrinkage ◽  
Degree Of Crystallinity ◽  
Bend Strength ◽  
Western Turkey ◽  
X Ray ◽  
Value Loss ◽  
Dry Pressing ◽  
Kaolin Deposit

AbstractThe Yaylayolu kaolin deposit is situated in the vicinity of Tavşanlı, Kütahya, western Turkey. Mineral identification and characterization studies were conducted using powder X-ray diffraction (XRD), differential thermal analyses (DTA), scanning electron microscopy with an energy dispersive X-ray spectrometer (SEM-EDX), X-ray fluorescence (XRF) and Fourier transform infrared spectroscopy (FTIR) techniques. The degree of crystallinity, Hinckley's index (HI) and the Stoch index (SI) values were determined for kaolinite from the deposit.Five representative samples from the kaolin deposit were used for ceramic technological tests. Particle size distribution, pH value, loss on ignition, A12O3, Fe2O3and TiO2contents were determined, drying shrinkage, firing shrinkage, dry bend strength, fired bend strength, water absorption, pfefferkorn plasticity index, whiteness of the fired and unfired samples (L* value) and bulk density were measured. The kaolin was found to be suitable for making white cement and wall tiles, floor tiles, and tableware items which are shaped by dry pressing and extrusion.

Detector strategies for environmental scanning electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1296-1297
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
High Vacuum ◽  
Environmental Scanning Electron Microscopy ◽  
Charge Carriers ◽  
Environmental Scanning ◽  
Surface Information ◽  
X Ray ◽  
Detector Electrode ◽  
Electrons And Ions ◽  
Low Energy Electrons ◽  
Environmental Sem

Environmental SEM operate at specimen chamber pressures of ∼20 torr (2.7 kPa) allowing stabilization of liquid water at room temperature, working on rugged insulators, and generation of an environmental secondary electron (ESE) signal. All signals available in conventional high vacuum instruments are also utilized in the environmental SEM, including BSE, SE, absorbed current, CL, and X-ray. In addition, the ESEM allows utilization of the flux of charge carriers as information, providing exciting new signal modes not available to BSE imaging or to conventional high vacuum SEM.In the ESEM, at low vacuum, SE electrons are collected with a “gaseous detector”. This detector collects low energy electrons (and ions) with biased wires or plates similar to those used in early high vacuum SEM for SE detection. The detector electrode can be integrated into the first PLA or positioned at any other place resulting in a versatile system that provides a variety of surface information.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

scholarly journals Structure of the amorphous titania precursor phase of N-doped photocatalysts

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8619-8627
Author(s):  
I. E. Grey ◽  
P. Bordet ◽  
N. C. Wilson
Keyword(s):  
Thermal Analyses ◽  
Real Space ◽  
Ammonia Solution ◽  
Scattering Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Amorphous Titania ◽  
Precursor Phase ◽  
Titania Precursor ◽  
Titanyl Sulphate

Amorphous titania samples prepared by ammonia solution neutralization of titanyl sulphate have been characterized by chemical and thermal analyses, and with reciprocal-space and real-space fitting of wide-angle synchrotron X-ray scattering data.

scholarly journals Synthesis and Na+ Ion Conductivity of Stoichiometric Na3Zr2Si2PO12 by Liquid-Phase Sintering with NaPO3 Glass

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3790
Author(s):  
Yongzheng Ji ◽  
Tsuyoshi Honma ◽  
Takayuki Komatsu
Keyword(s):  
Solid State ◽  
Liquid Phase ◽  
Sintering Temperature ◽  
Liquid Phase Sintering ◽  
Ion Conductivity ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Sintering Time ◽  
Lower Activation

Sodium super ionic conductor (NASICON)-type Na3Zr2Si2PO12 (NZSP) with the advantages of the high ionic conductivity, stability and safety is one of the most famous solid-state electrolytes. NZSP, however, requires the high sintering temperature about 1200 °C and long sintering time in the conventional solid-state reaction (SSR) method. In this study, the liquid-phase sintering (LPS) method was applied to synthesize NZSP with the use of NaPO3 glass with a low glass transition temperature of 292 °C. The formation of NZSP was confirmed by X-ray diffraction analyses in the samples obtained by the LPS method for the mixture of Na2ZrSi2O7, ZrO2, and NaPO3 glass. The sample sintered at 1000 °C for 10 h exhibited a higher Na+ ion conductivity of 1.81 mS/cm at 100 °C and a lower activation energy of 0.18 eV compared with the samples prepared by the SSR method. It is proposed that a new LPE method is effective for the synthesis of NZSP and the NaPO3 glass has a great contribution to the Na+ diffusion at the grain boundaries.

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