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Graphene oxide-multiwalled carbon nanotubes composite as an anode for lithium ion batteries

, other mechanisms, like micro-cavities lithium storage or surface storage are taken into consideration [ 1 , 17 ]. The reason of excess of the capacity is still the matter of intensive studies and discussions. The understanding of the nature of lithium storage into rGO can contribute to improvement of the properties of this very promising candidate for a LIB’s high capacity anodes. However, to determine the mechanism of excess of the capacity a model system is required. So far, there are no experimental results of the electrochemical lithium storage in a nonreduced GO

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Synthesis and electrical characterization of Ca2Nd4Ti6O20 ceramics

dielectric losses from 100 kHz to 1 MHz were measured using a precision LCR meter (4284 A) with an applied AC voltage of 100 mV from room temperature up to 700 °C in air. Polarization-electric field (P-E) hysteresis loop measurements were made at room temperature in silicone oil using a Radiant Technology RT-66A standardized ferroelectric test system and Trek 609E-6 high voltage amplifier. These measurements were performed at a maximum applied voltage of 20 kV/cm. Impedance spectroscopy of the sample was carried out using an HP-4192A impedance analyzer (Agilent

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Microstructural, optical and electrical properties of Cl-doped CdTe single crystals

1 Introduction CdTe is of considerable technological importance for use in semiconductor-based radiation detection applications, such as medical imaging and homeland security fields. The fabricated CdTe radiation detectors can be operated at room-temperature due to the favorable band gap (1.44 eV) and have been researched by various groups [ 1 – 7 ]. High resistivity is required for any semiconductor material to be used in realizing high-performance radiation detectors. Because high bias voltage is needed to improve the charge collection efficiency of

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Effect of lead salts on phase, morphologies and photoluminescence of nanocrystalline PbMoO4 and PbWO4 synthesized by microwave radiation

1 Introduction Molybdate and tungstate are inorganic compounds which have very interesting properties for applications such as luminescent materials, electro-optic materials, scintillators and catalysts [ 1 , 2 ]. PbMoO 4 and PbWO 4 are classified in these groups and have application in high-energy physics. They are characterized by high density, short decay time and high-irradiation damage [ 3 – 5 ]. Photonic emission of PbMoO 4 has only blue color but PbWO 4 has two types of colors: blue (2.8 eV to 2.9 eV) and green (2.3 eV to 2.5 eV) [ 6

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Characterization of deep-level defects in GaNAs/GaAs heterostructures grown by APMOVPE

Experimental The GaNAs epitaxial layers were grown on Si-doped (~10 18 cm −3 ) n-GaAs substrates using an atmospheric pressure metalorganic vapour phase epitaxy (APMOVPE) system, equipped with AIX200 R&D AIXTRON horizontal reactor. Trimethylgallium (TMGa), arsine (AsH 3 : 10 %mixture in H 2 ) and tertiarybutylhydrazine (TBHy) were used as grow precursors and they were transported by passing a high purity H 2 through the bubblers. The undoped heterostructures consisted of a 450 nm thick undoped GaAs buffer layer and of about 300 nm thick GaNAs epitaxial layer. The

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Characterization of magnetic biochar amended with silicon dioxide prepared at high temperature calcination

1 Introduction Calcination process is considered to increase hardness of different composite materials and prevent their breakage [ 1 ]. Generally, high temperature selective environment-based calcination alters material textural and mineralogical characteristics, which for some composite materials improves surface properties and attracts their environmental applications [ 2 ]. However, Mahmood et al. [ 3 ] found reduction of pollutants removal in mixed oxides calcined at higher temperature. Numerous powdered materials have been utilized for toxic metals

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VO2(B) conversion to VO2(A) and VO2(M) and their oxidation resistance and optical switching properties

. Table 1 The crystallography data of some important types of VO 2 polymorph. Phase T c [°C] T c : phase transition temperature; Cs: Crystal system; Sg: Space group. Cs T c : phase transition temperature; Cs: Crystal system; Sg: Space group. Sg T c : phase transition temperature; Cs: Crystal system; Sg: Space group. a [Å] b [Å] c [Å] β (°) Ref. VO 2 (B) — Monoclinic C2/m 12.03 3.693 6.420 106.6 [17] VO 2 (M) 68 Monoclinic P2 1 /c 5.743 4.157 5.375 122.6 [18] VO 2 (R) 68 Tetragonal P4

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Synthesis and characterization of Ag@polycarbazole nanoparticles using different oxidants and their dispersion behavior

electrical and luminescence peculiarities and magnitude of such type of properties can be enhanced using nanometallic components within the polymer matrix[ 4 ]. Among the conductive composite materials, silver is the most often used because of its high electrical conductivity and oxidation resistance. In this way, nano Ag is a potential material to increase electrical and lumines-cent properties of encasing polymers. Among the conductive and luminescent polymers, PCz bears special significance due to the electron and hole transporting behavior that enables its

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Structural, optical and dielectric studies of lithium sulphate monohydrate single crystals

high temperature super-ionic phases [ 22 – 24 ]. These systems have high cationic mobilities, and hence, exhibit good fast-ion conductivity at higher temperatures [ 25 , 26 ]. Such kind of materials finds application in solid state batteries and fuel cells where they can be used as electrolyte materials or fast-ionic conductors. Proton conductors also find application for the development of new generation of energy storage and fuel cells. Lithium sulphate is an excellent lithium ion conductor in the high temperature α-phase but it is also a proton conductor in

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Electronic structure, first and second order physical properties of MPS4: a theoretical study

1 Introduction Modern technological developments require more research on the physical properties of materials such as optical and mechanical properties, which are closely linked to crystalline and electronic structures of the materials. In a recent survey [ 1 ], it has been pointed out that chalcogenide materials are potential candidates for nonlinear optical applications. They possess high nonlinear optical (NLO) coefficients and large transparency domains extending in the middle-IR region above 5 µm. Furthermore, chalcogenide materials show rich

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