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Using cobalt nitrate, nickel nitrate, ammonium fluoride and urea as raw materials, tellurium dioxide as tellurium source and foam nickel as substrate, NiCoTe2 electrode materials were prepared by secondary hydrothermal synthesis method. The material structure and morphology were characterized using XRD and SEM, and the electrochemical performance of the material was studied using cyclic voltammetry, constant current charge discharge testing, and AC impedance testing. The results showed that with the increase of hydrothermal temperature, the diameter of the nanoneedle/rod-shaped morphology of the electrode material increased, and nanoparticles adhered to the surface, increasing the surface area of the electrode material in contact with the electrolyte and the exposure of active sites; The material prepared at a hydrothermal temperature of 140 °C exhibits the best electrochemical performance, with an internal resistance of 0.63 Ω for the electrode material. When the current density is 1 A/g, the mass specific capacitance can reach 781.5 F/g. [ABSTRACT FROM AUTHOR]

The objective of this study is to use Phy-X/PSD computer software between 0.284 and 1.33 MeV to examine the impact of increasing TeO2 mol% on the radiation shielding properties of Yb3+-doped Calcium Borotelurite glasses with the formula CaF2-CaO-B2O3-TeO2-Yb2O3. For the investigated samples, the mass attenuation coefficient (MAC) at 0.284 MeV ranges between 0.126 and 0.154 cm2/g. The range of the MAC for the samples under investigation at 0.347 MeV is 0.109–0.123 cm2/g. The glass with a composition of 10CaF2-7.9CaO-27.6B2O3-54TeO2-0.5Yb2O3 has the largest MAC. The results also showed that the effective atomic number (Zeff) is increased by the addition of TeO2, and the glasses with 10 and 54 mol% of TeO2 had the lowest and highest Zeff. The half value layer (HVL) decreased as energy increased from 0.284 to 1.33 MeV, and the lowest HVL is observed at 0.284 MeV for the sample Te54, which is equal to 3.068 cm, as opposed to Te10, which has an HVL of 4.235 cm. Additionally, we assessed the tenth value layer (TVL) for the current system and observed that TVL decreases as TeO2 content increases. Te54, a sample with 54 mol% of TeO2, has the lowest TVL value and, as a result, exhibits the best radiation attenuation performance when compared to other chosen glasses. We compared the present glasses with other materials and the results showed that all the CaF2-CaO-B2O3-TeO2-Yb2O3 glasses have better attenuation performance that RS-253-G18. [ABSTRACT FROM AUTHOR]

A study was conducted to investigate how the addition of WO3 affects the mechanical, optical, and photon attenuation properties of TeO2–Na2O glass systems. In this study, four glass systems categorized as W5, W10, W15, and W20 were studied to evaluate the impact of WO3 on TeO2–Na2O glass systems in view of the feature of mechanical, optical, and photon attenuation. The rising values of elastic moduli suggest that increasing WO3 on TeO2–Na2O glass systems makes the glassy structure more stable. Incorporating WO3 into TeO2–Na2O glass systems results in an increased energy band gap, rising from 2.83 to 2.95 eV. This phenomenon, in turn, leads to a decrease in the refractive index, dielectric constant, and optical dielectric constant values from 2.444 to 2.411, 5.975 to 5.811, and 4.975 to 4.811, respectively. While the linear attenuation coefficient (LAC) of the examined glass systems (W5, W10, W15, and W20) displayed a comparable pattern, the LAC value of glass sample W20 stood out as the highest among them. However, due to the addition of WO3 on the TeO2–Na2O glass system, at a lower energy region from 0.0284 to 0.06 MeV, there was a little variation among the mass attenuation coefficients of these glass systems studied herein, but a negligible variation was found from 0.662 to 2.51 MeV. The studied glass sample W20 with the highest amount of WO3 (20 mol%) on the TeO2–Na2O glass system displayed the lowest half-value layer. However, glass samples W5, W10, and W15 exposed 1.29, 1.07, and 1.03 times higher values of mean free path than W20. In addition, the values of the half-value layer were compared with the literature data of WO3–MoO3–TeO2, BaO–Li2O–B2O3, and CaF2–BaO–P2O5 glass systems. Studied glass sample W20 showed the maximum shielding performance from energy 0.284 to 2.51 MeV.

In various medical, industrial, and nuclear facilities, it is very necessary to have enough shielding against the radiation released by regularly employed isotopes. In this work, we concentrate on nuclear security as well as the radiation shielding against gamma attenuation capabilities of the borate glasses, including Te and Cu. These glasses have the chemical form of (100-x)[30B2O3–70TeO2]-xCuO, where x = 0, 0.005, 0.01, 0.015, 0.02 wt%. The systems were represented by five distinct samples, labelled as BTCu-20, BTCu-15, BTCu-10, BTCu-5, and BTCu-0, where the number refers to the percentage of CuO in the mixture and the remainder is made up of TeO2 and B2O3. Through the use of FLUKA simulations, the basic characteristics associated with gamma shieldings, such as attenuation and transmission factors, were examined for the particular energy range of 238–1408 MeV emitted from 133Ba, 137Cs, 60Co, 152Eu, and 232Th. The effect of the systematic replacement of CuO by B2O3 and TeO2 on the shielding qualities was explored in depth for gamma radiation. In addition, comparison research was carried out between the currently available borate glasses and the traditional shielding materials. According to the findings of the current investigation, the GHVL was found to be its lowest at 238 keV with values of 0.87, 0.92, 0.98, 1.04, and 1.10 (cm) for BTCu-0, BTCu-5, BTCu-10, BTCu-15, and BTCu-20 glasses, respectively. This points to the possibility that the BTCu-0 sample might be used in radiation shielding applications, which would result in increased nuclear safety.

A direct-doping method was tested to design new composite-glasses by incorporating lanthanum niobate nanocrystals (NC) in tellurite glasses. NC powder were grinding with glass powder before heating-quenching, with the main investigation approached of best parameters for NC suitable homogenization but limited dissolution. Thermal analysis signalizes that prior heat-treatment of NC promotes higher transparency and limits NC dissolution. These materials with visually detectable NC aggregates exhibited glass transition temperatures close to the starting glass. LaNbO4 phase was hardly detected by X-ray diffraction because of the low weight ratio and partial dissolution but the monoclinic polymorph could be identified for lower time. UV-visible-NIR transmission spectra also related progressive lower transparency with light scattering of NC aggregates. Photoluminescence suggest that lower times allowed to ensure the NC environment with lower crystallinity around Eu3+-ions in final composite-glass. These results pave the way for designing new materials containing NC not achievable by conventional nucleation-growth methods.

We investigated the radiation shielding competence for TeO2–V2O5–MoO3 glasses. The Phy-X software was used to report the radiation shielding parameters for the present glasses. With an increase in TeO2 and MoO3 content, the samples' linear attenuation coefficient improves. However, at low energies, this change is more apparent. At low energy, the present samples have an effective atomic number (Zeff) that is relatively high (in order of 16.17–24.48 at 0.347 MeV). In addition, the findings demonstrated that the density of the samples is a very critical factor in determining the half value layer (HVL). The minimal HVL for each sample can be found at 0.347 MeV and corresponds to 1.776, 1.519, 1.391, 1.210 and 1.167 cm for Te1 to Te5 respectively. However, the highest HVL of these glasses is recorded at 1.33 MeV, which corresponds to 3.773, 3.365, 3.218, 2.925 and 2.908 cm respectively. The tenth value layer results indicate that the thickness of the specimens needs to be increased in order to shield the photons that have a greater energy. Also, the TVL results demonstrated that the sample with the greatest TeO2 and MoO3 concentration has a higher capacity to attenuate photons.

Physical vapor deposition method was used for the preparation of nanostructured TeO2. Different morphologies of TeO2 are synthesized using a physical evaporation method with Te powder as the source material and quartz SiO2 as the growth substrates. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and ultravioletvisible (UV-Vis) analyses are used to characterize the structural, morphological, and optical properties of the TeO2 products obtained. By varying the annealing temperature, different morphology of TeO2 structures is investigated. TeO2 nanostructure progress is initiated by the crystallization of particles. Different temperatures have different effects on structures, which are discussed. The films as deposited nature was amorphous; crystallization occurred at a higher annealing temperature (175 oC). With an increase in annealing temperature, the TeO2 films grain size increased. The research also points to the impact of post-deposition thermal annealing temperatures in excess of 100 °C in enhancing TeO2 film characteristics. [ABSTRACT FROM AUTHOR]

Herein, a computational technique that combines density functional theory and the finite difference method is presented to enable the calculation of the Raman spectra of large models of oxide glasses. The calculated Raman spectra of amorphous TeO2 are found to be in excellent agreement with the experimental data. A strong peak in the low‐frequency range of the Raman spectra is observed and attributed to the Boson peak. According to atomic‐scale analysis, this peak is assigned to collective vibrations of nanoclusters that are formed by the structural units of the glass. Two general factors that influence the Boson peak intensity are established. The first factor concerns the intensity of the low‐frequency peak in TeO2 vibrational density of states. The second factor is related to the low‐frequency vibrational state occupancy at fixed temperature, which obeys the Bose–Einstein statistic. It is found that even a small shift toward high frequencies leads to a significant decay of the vibrational state occupancy. This correlates quite well when the Raman spectra of TeO2 glass are compared to the spectra of fused silica. The technique can be readily applied to the large set of amorphous systems. [ABSTRACT FROM AUTHOR]

Leishmaniasis is a group of diseases caused by infection with Leishmania parasites. The lesions that develop as a result of leishmaniasis can vary depending on the species of the parasite and the type of leishmaniasis. Cutaneous leishmaniasis is the most common form of the disease and it results in skin sores or ulcers. Materials with manganese oxide (Mn2O3) nanoparticles and tellurium oxide (TeO2) nanorods have been shown to have antibacterial, antifungal, and antiparasitic effects. The purpose of this study was to ascertain how Mn2O3 and TeO2 nanoparticles affected Leishmania major-caused wound healing in rats. The albino rats were separated into four groups of five once a lesion appeared on their tails. In the two treatment groups, Mn2O3 and TeO2 nanoparticles were injected every day, once a day, intra-wound in three places, and in the meglumine antimoniate group, the drug was injected intramuscularly for five weeks. The albino rats in the negative control group did not receive any medication. The size of the wounds in the group treated with Mn2O3 nanoparticles did not differ significantly from the control group that did not receive treatment, however the diameter of the wounds in the group treated with TeO2 nanorods did change significantly from the control group that did not receive treatment. It was, however, larger than the group that received meglumine antimoniate treatment. TeO2 nanorods, as opposed to Mn2O3 nanoparticles, had an in vivo anti-Leishmanial potential. [ABSTRACT FROM AUTHOR]

Herein, a computational technique that combines density functional theory and the finite difference method is presented to enable the calculation of the Raman spectra of large models of oxide glasses. The calculated Raman spectra of amorphous TeO2 are found to be in excellent agreement with the experimental data. A strong peak in the low‐frequency range of the Raman spectra is observed and attributed to the Boson peak. According to atomic‐scale analysis, this peak is assigned to collective vibrations of nanoclusters that are formed by the structural units of the glass. Two general factors that influence the Boson peak intensity are established. The first factor concerns the intensity of the low‐frequency peak in TeO2 vibrational density of states. The second factor is related to the low‐frequency vibrational state occupancy at fixed temperature, which obeys the Bose–Einstein statistic. It is found that even a small shift toward high frequencies leads to a significant decay of the vibrational state occupancy. This correlates quite well when the Raman spectra of TeO2 glass are compared to the spectra of fused silica. The technique can be readily applied to the large set of amorphous systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Strain increases α-TeO 2 bandgap and decreases β-TeO 2 bandgap. • Lattice parameters decrease under strain, uniformly in α-TeO 2 , variably in β-TeO 2. • Strain shifts O-2 p and Te-5 p states, affecting electronic structure. • Anisotropic absorption shifts with increased polarizability and refractive index. • Enhanced nonlinear susceptibility boosts SHG and frequency conversion. This study examines the effects of 2 % compressive strain on the structural, electronic, and optical properties of α-TeO 2 and β-TeO 2 polymorphs. α-TeO 2 's bandgap increases from 3.64 eV to 3.70 eV, while β-TeO 2 's decreases from 3.632 to 3.53 eV. Lattice parameters uniformly reduce in α-TeO 2 , but vary dissimilarly in β-TeO 2. PDOS analysis shows O-2 p and Te-5 p states dominate near the band edges. Optical behavior is anisotropic, with enhanced polarizability and refractive indices under strain. Nonlinear optical properties improve with increased strain, especially the non-linear susceptibility components, which are relevant for second-harmonic generation. Born Effective Charges show increased Te polarization and reduced oxygen polarization, impacting dielectric response. [ABSTRACT FROM AUTHOR]

PMMA (Poly methyl methacrylate) composites have promising potential for applications in optics and dielectric energy storage. To investigate the effects of TeO 2 contents in PMMA in this respect, we studied their composites on light absorption in the UV visible range, structural analysis via X-ray diffraction, dielectric characteristics, and free volume behavior. We added up to approximately 7 % of the weight concentration of the TeO 2 micropowder to the PMMA matrix for effective dispersion because of the limitations of ultrasonic agitation. The XRD data demonstrate a widening of the peaks with a filler content of up to 4.8 % and agglomeration at 7 %, indicating TeO 2 particle contact. An increase in absorbance was observed in the UV visible spectrum of the PMMA/TeO 2 composites with increasing TeO 2 content up to 4.8 %. The dielectric constants exhibit a positive correlation with higher quantities of TeO 2 , and the polarization mechanism is interpreted by interface polarization and free volume. The free volume measured by positron annihilation lifetime spectroscopy (PALS) increases to 4.8 % but decreases to 7 %. The effect of the free volume within the matrix on the polarization distribution of TeO 2 influenced the dielectric constant and the loss factor, which increased to 4.8 % and then decreased to 7 % due to agglomeration. • Free volume behavior of PMMA/TeO 2 was investigated using the Positron Spectroscopy in both the glassy and molten phases. • The XRD spectrum reveals a broadened peak with TeO 2 content consistent with the free volume. • UV–visible absorbtion spectra aligns well with composite free volume. • Free volume quantity interpretes dielectric permitivity and loss factor using filler-matrix interface polarization. • PMMA/TeO 2 composites exhibit highly favorable dielectric characteristics, increasing the dielectric constant about 20 %. [ABSTRACT FROM AUTHOR]

In this research, polymers were fabricated through combining polyester, boron oxide (B2O3), and Tellurium oxide (TeO2). B2O3 has good neutron absorption and TeO2 is not only highly dense (5.670 g/cm3) but also environment-friendly, compared to PbO, as well as being a good photon absorber. The radiation protection features for five investigated samples were examined utilizing an HPGe detector and point sources Am-241, Cs-137, and Co-60. The accuracy of the experimental setup of this experiment was proven through the linear attenuation coefficient (LAC) values obtained from the theoretical (XCOM) and experimental (HPGe) values of the newly developed polymers. The attained results showed that the values of LAC decrease with increasing energy. Moreover, at low energy, a noteworthy increase was found for the LAC values with the addition of TeO2. Due to the increase in TeO2 content of the polymers, the value of the half value layer (HVL) decreases from 6.073–4.193 cm at energy 0.662 MeV, from 7.973–5.668 cm at energy 1.173 MeV, and 8.514–6.061 cm at energy 1.333 MeV. The values of the effective atomic number (Zeff) showed an improvement with the increase in TeO2 content in the polymers. For example, at energy 0.150 MeV, the Zeff values of the prepared sample followed this decreasing trend - PBT-40 > PBT-30 > PBT-20 > PBT-10 > PBT-0. [ABSTRACT FROM AUTHOR]

In this study, eight glass samples were prepared with the composition of [x Bi 2 O 3 -(75-x) B 2 O 3 –15TeO 2 –5MgO–5PbO; where x = 0, 10, 20, 25, 30, 40, 50, and 60 mol%]. In the composition of those glass samples, various amountsof B 2 O 3 were replaced by Bi 2 O 3 to improve the glass material's radiation shielding capability. The mechanical properties of these glasses have been evaluated using densimeter and microhardness. The Vickers microhardness (Hv) slightly decreases as the amount of Bi2O3 increases due to the formation of Non-Bridging Oxygen (NBO). To evaluate the radiation shielding effectiveness of the prepared glass samples, we performed Monte Carlo simulations of several shielding parameters. The mass attenuation coefficients of the experimentally produced BTMPBi glass series were calculated using NIST and MCNP6, and reasonable agreement was found between the simulation and experimental results. The relative difference between NIST and MCNP6-based results was calculated, and the maximum deviation was 2.21% for the 1173 keV gamma ray incident in the BTMPBi60 glass sample. The value of the mean free path of those prepared glass samples maintained the following trend - BTMPBi0> BTMPBi10> BTMPBi20> BTMPBi25> BTMPBi30> BTMPBi40> BTMPBi50>BTMPBi60. The prepared glass sample BTMPBi0 showed a 2.6 times higher value of the mean free path at energy 1332 KeV compared with the prepared BTMPBi60. Analyzing the composition of the prepared glass samples, it is clear that the greater the amount of Bi 2 O 3 the greater the value of linear attenuation coefficient (LAC) and effective atomic number. Based on the results, it can be concluded that the glass sample containing 60 mol % of Bi 2 O 3 (BTMPBi60) exhibited the highest radiation shielding capability among all of the prepared samples. [ABSTRACT FROM AUTHOR]

Monolayer semiconductors with unique mechanical responses are promising candidates for novel electromechanical applications. Here, through first-principles calculations, we discover that the monolayer β -TeO2, a high-mobility p -type and environmentally stable 2D semiconductor, exhibits an unusual out-of-plane negative Poisson's ratio (NPR) when a uniaxial strain is applied along the zigzag direction. The NPR originates from the unique six-sublayer puckered structure and hinge-like Te-O bonds in the 2D β -TeO2. We further propose that the sign of the Raman frequency change under uniaxial tensile strain could assist in determining the lattice orientation of monolayer β -TeO2, which facilitates the experimental study of the NPR. Our results is expected to motivate further experimental and theoretical studies of the rich physical and mechanical properties of monolayer β -TeO 2 ., (© 2024 IOP Publishing Ltd.)

This paper has focused on the investigation of gamma and neutron attenuation properties of Li 2 O–B 2 O 3 –P 2 O 5 –TeO 2 glass system. Gamma shielding parameters such as mass attenuation coefficients ( μ m ), effective atomic numbers (Z eff), half value layers (HVL), tenth value layers (TVL), mean free path (MFP), effective electron density (Ne), equivalent atomic numbers (Z eq) of investigated glass samples have been calculated in a wide photon energy range of 0.02–20 MeV using MCNPX general purpose Monte Carlo code. The calculated results for mass attenuation coefficients were compared with XCOM. In addition, exposure buildup factors (EBF) and energy absorption buildup factors (EABF) of investigated glasses were determined by using the G-P fitting method. The results showed that sample 9 with the highest density had the lowest HVL, TVL and MFP values among the investigated glasses. Moreover, effective removal cross-sections (Σ R) and transmission factors (TFs) have been calculated. The obtained results have shown that the TeO 2 additive into glass samples had a positive effect on the nuclear protection performance of the investigated glass samples. It can be concluded that the impact of TeO 2 additive for nuclear radiation shielding applications can be further investigated in different types of glass systems. [ABSTRACT FROM AUTHOR]

Abstract The objective of the study was the structural analysis of the 70TeO2-5XO-10P2O5-10ZnO-5PbF2 (X = Mg, Bi2, Ti) tellurite glasses doped with ions of the rare-earth elements Er3+, based on the PALS (positron annihilation lifetime spectroscopy) method of measuring positron lifetimes. Values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects, the sizes of which range from a few angstroms to a few dozen nanometers. Experimental positron lifetime spectrum revealed existence of two positron lifetime components τ 1 andτ 2. Their interpretation was based on two-state positron trapping model where the physical parameters are the positron annihilation rate and positron trapping rate.

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Thermally activated processes in cordierite-based ceramics were investigated to determine the effect of the mechanical activation and the addition of TeO2 on kinetic and thermodynamic parameters of these processes. Using a combination of dilatometry and DTA measurements in the 100–1400 °C temperature range, it was established that both the mechanical activation and the addition of TeO2 have a significant effect on processes in cordierite-based ceramics. A combination of 5 mass% addition of TeO2 and mechanical activation for 40 min reduced the sintering temperature of cordierite ceramics to around 1100 °C. In addition, the analysis of DTA measurements of mechanically activated samples indicates that the mechanical activation leads to intensification of the cordierite formation through an increase in concentration of surface defects and an increase in grain contact surface in the initial powder. [ABSTRACT FROM AUTHOR]

Sintering of pure cordierite 2MgO:2Al2O3:5SiO2, and cordierite with the addition of 5 mass % TeO2 was studied. Green bodies were prepared from powder mixtures mechanically activated in a high-energy planetary mill, shaped by uniaxial (20 MPa) and cold isostatic pressing (1000 MPa). The pressure-less sintering of these specimens was performed at 1350°C for 1 h. High relative density over 95% of the theoretical value was obtained through solid-state reaction and pressure-less sintering of powder activated for 40 min, and for the first time reported in the literature. Phase composition and microstructures of sintered samples were determined by XRD and SEM, coupled with EDS mapping. The real part of the complex relative permittivity of the samples was measured at 200 MHz. The loss tangent of all samples was below the resolution of the measurement setup. A strong correlation between the relative permittivity and the density agrees with previously published data. [ABSTRACT FROM AUTHOR]

We report the gas-sensing properties of pristine and SnS2 functionalized TeO2 nanowires (NWs). TeO2 NWs were synthesized by a vapor–liquid–solid growth method, and SnS2 functionalization was performed using an atomic layer deposition technique followed by thermal treatment. Structural and morphological analyses verified the formation of pristine and SnS2 functionalized TeO2 NWs with desired composition, phase, and morphology. Interestingly, sensing results showed that the pristine TeO2 NW gas sensor had better sensing properties relative to the SnS2 functionalized TeO2 NW gas sensor. An underlying sensing mechanism is explained in detail, and reasons for the decrease of sensing performance with the SnS2 functionalized TeO2 NW sensor was attributed to the coverage of TeO2 surface by the SnS2 nanoparticles. [ABSTRACT FROM AUTHOR]

Cordierite 2MgO+2Al2O3+5SiO2 is frequently used ceramic material, that is commonly used as a carrier of electrical components due to its low dielectric constant (~ 5), and low temperature thermal expansion coefficient (20·10-7 oC-1). In order to accelerate the process of sintering, 5.00 mass% TeO2 was added to the starting mixtures. System was tested in two parallel mixtures, one with no additives, and the other one with TeO2. The mechanical activation of the both mixtures was performed in a highenergy ball mill in time intervals from 0 to 40 min with ball to powder mass ratio 1:40. The particle size analysis (PSA) was employed in order to determine the changes in the particle size of the mechanically treated powders. The phase composition of the starting powders as well as microstructures was analyzed by the means of X-ray diffraction method and SEM.

In this paper, the tellurite glasses76.4TeO2-12Nb2O5- 12.6ZnO doped with 3000ppm Tm2O3 ions were prepared by conventional melt quenching method. The optical properties of the glasses were estimated by measuring UV.Vis-NIR spectroscopy in the range from 200 to 2500 nm and linear refractive indices (n) at different wavelength was estimated. From the absorption edge studies, the value of optical band gap (Eopt) was determined. Moreover, the nonlinear refractive index (n2), third-order nonlinear susceptibility (Ô(3)), and nonlinear absorption coefficient, (β), were observed. It is noticed that (n2), Ô(3) and β increase by decreasing the value of optical band gap (Eopt). The classical McCumber theory was used to evaluate the emission cross-sections for the 3F4 3H6 transition at a wavelength of around 2µm. Gain cross-section for the Tm3+ laser transition 3F4? 3H6 was obtained. These glasses have the effective emission cross section bandwidth (108 nm) and large stimulated emission cross-section (28.37?~10-21cm2). Spectroscopic properties indicate that these glasses doped with Tm3+ are a promising candidate for optical applications and may be suitable for optical fibre lasers and amplifiers. Furthermore, the structures of these glasses were analyzed by Raman Ramanspectroscopy. [ABSTRACT FROM AUTHOR]

The crystal structure of γ-TeO2 was redetermined on the basis of single-crystal X-ray diffraction data. The previous structure determination of this modification was based on laboratory powder X-ray diffraction data [Champarnaud-Mesjard et al. (2000). J. Phys. Chem. Solids, 61, 1499–1507]. The current redetermination revealed all atoms with anisotropic displacement parameters, accompanied with a much higher accuracy and precision in terms of bond lengths and angles, and the determination of the absolute structure. The crystal structure consists of TeO4 bisphenoids that combine through corner-sharing of all their oxygen atoms into a three-dimensional framework.

An acousto-optic tunable filter (AOTF) is used in the development of hyperspectral imagers from the ultraviolet to the longwave infrared. The spectral response of the transmitted intensity from an AOTF with a rectangular transducer has a sinc2(x) distribution and so far the light leakage from the sidelobes is ignored in hyperspectral imagers. When unpolarized white light is incident on an AOTF, two orthogonally polarized diffracted beams at a specific wavelength with a narrow bandpass filter are transmitted for an applied radio frequency (RF), and an image cube is obtained by tuning the applied RF. We carried out a detailed study of light transmitted through the sidelobes of a TeO2 AOTF operating in the shortwave infrared region from 0.9 to 1.7  μm to image a scene containing a laser. The AOTF imaging system used telecentric confocal optics that compensate for AOTF aberrations. We used a 16-channel RF driver with independent amplitude and frequency control. By switching off specific RF signals applied to the AOTF, the detailed sidelobe structure for the transmitted intensity was measured and compared with theory. We found that close to 10% of the transmitted light is leaked through the sidelobes. Here, we present our experiment and analysis of the results. [ABSTRACT FROM AUTHOR]

TeO2 nanowires were synthesized on Au-coated glass substrates at 450℃ by thermal evaporation method using Te powders as the source material. The structures and morphology of TeO2 nanowires were characterized by X-ray diffraction， scanning electron microscopy， and transmission electron microscopy. A possible growth mechanism was proposed. The results showed that TeO2 nanowires with a tetragonal structure were approximately 70~200nm in diameter and several hundreds of micrometers to 2mm in length. By the morphology observation of the as-prepared products obtained at different growth times， the growth process of TeO2 nanowires was analyzed. It is concluded that the growth of TeO2 nanowires is based on vapor-solid growth mechanism， where Au film deposited on the glass substrates is possibly used for inducing and accelerating the growth of TeO2 nanowires. [ABSTRACT FROM AUTHOR]

This work intends to analyse the microstructure of paratellurite (TeO2 single crystals) plastically deformed at high temperature (∼870 K) in uniaxial compression along [110]. Samples have been mechanically tested, and thin foils have been cut from them, corresponding to the slip systems to be observed in transmission electron microscopy. The study of the dislocation substructure in this material is rather complex due to its high anisotropy. Microstructural observation by TEM has put into evidence the presence of dislocation dissociation. This is the first work reporting this fact. From the equilibrium distance between partials, an estimation of the stacking fault energy has been carried out.En este trabajo se pretende analizar la microestructura de monocristales de TeO2 (paratelurita) deformados plásticamente en compresión uniaxial a alta temperatura (∼870 K) en distintas condiciones. Para ello, se han ensayado muestras con orientación cristalográfica [110], y se han cortado láminas correspondientes a los planos de deslizamiento para ser observadas con microscopía electrónica de transmisión. El estudio de la subestructura de dislocaciones en este material es complejo debido a su alta anisotropía. La observación de dicha microestructura ha puesto de manifiesto la presencia de disociación de dislocaciones. Es la primera vez que se encuentra este fenómeno en la paratelurita. De la distancia de equilibrio entre dislocaciones parciales, se ha podido obtener una estimación de la energía de falta de apilamiento en este sistema.

A system based on the xLi2O-(1-x)[30V2O5-70TeO2] glassy system have been prepared by classical melt-quenching technique and their thermal and electrical properties were studied in the range from x = 0 up to 0.4. It has been observed on these glasses that with increase of Li2O concentration Tg decreases as well conductivity, however when x reaches 0.2-0.3 values conductivity begin to increase (Tg behavior remains unaltered). Results have been discussed on the basis of network modification that would occur in the glass base structure by the addition of Li2O. Those glasses show high promise as potential mixedionic materials.El sistema vítreo xLi2O-(1-x)[30V2O5-70TeO2] ha sido preparado por la técnica tradicional de enfriamiento rápido (“melt quench”) y sus propiedades térmicas y eléctricas han sido estudiadas en el rango de x = 0 a 0.4. En este sistema se ha observado que la transición vítrea y la conductividad disminuyen a medida que aumenta la concentración de Li2O pero, por otro lado, cuando x = 0.2-0.3 la conductividad comienza a aumentar (la transición vítrea continua disminuyendo). Los resultados obtenidos se han discutido en términos de modificación de la estructura vítrea base en relación a la adición de Li2O y en términos de basicidad óptica. Estos vidrios muestras propiedades prometedores como materiales de conductividad mixta.

We report the synthesis of bead-like TeO2 nanowire ( NW)-based NO2 gas sensors using different O2 flow rates. The performance of these sensors was compared with that of a sensor based on smooth TeO2 NWs. The smooth TeO2 NWs were grown directly from Te powder by thermal evaporation in air ( i.e., without using O2 gas), while the bead-like TeO2 NWs were synthesized by transporting the evaporated Te precursor indirectly using reactive O2 gas at flow rates of 20-40 sccm. Scanning electron microscopy showed that the bead-like TeO2 NWs had uneven surfaces on which protruding nanoparticles with sizes of 20-100 nm were attached. The nanoparticle size varied with the O2 flow rate used. The responses of the gas sensors based on the multi-networked bead-like TeO2 NWs were indicative of a higher change in their electrical resistance as well as better selectivity to NO2 gas than those of the sensor based on the smooth TeO2 NWs. The individual responses-to 50 ppm NO2 gas at 350 °C-of the sensors based on TeO2 NWs fabricated without using O2 , using O2 at 20 sccm, using O2 at 30 sccm, and using O2 at 40 sccm were 113, 188, 220, and 345%, respectively. The underlying mechanisms responsible for the improved performances of the bead-like TeO2 NW-based sensors are also discussed. [ABSTRACT FROM AUTHOR]

• The effects of TeO 2 on the sintering of c-Si solar cell are systematically studied. • TeO 2 affects the morphology of the grids on the sintering process of Ag pastes. • TeO 2 promotes Ag pastes sintering and improves the conductivity of Ag grids. • TeO 2 promotes the growth of the Ag nanocrystallites in Ag/Si contact interface. • An optimal conversion efficiency of solar cells was acquired at TeO 2 content ∼40%. Glass frits, as a critical ingredient, plays an important role between Ag electrode and crystalline silicon (c-Si) solar cells and determines sintering properties of the silver paste and contact quality with c-Si solar cells. Here glass frits with different contents of TeO 2 are prepared and used to investigate the sintering process and effects of contact quality of Ag pastes on c-Si solar cells. Microstructures and electrical properties of the Ag/Si contact interface and performances of the resultant c-Si solar cells are characterized systematically. The results show that TeO 2 promotes the growth of Ag nanocrystallites in the glass layer between Ag grids and c-Si wafers, thus reduces the contact resistance of the Ag grids and improves the contact quality of the Ag/Si interfaces. Moreover, TeO 2 improves the densification and conductive performances of the Ag grids. However, excessive TeO 2 has a negative effect on the conductivity of the Ag grid due to the increased thickness of the glass layer. Based on the competing factors played by TeO 2 , the conversion efficiency is the highest at an optimized TeO 2 content ∼40%. [ABSTRACT FROM AUTHOR]

The spin Hamiltonian parameters (i.e., anisotropicgfactors and hyperfine structure constants) and local tetragonal distortions for Cu2+in crystalline and amorphous TeO2and GeO2are theoretically investigated using the high-order perturbation formulas of these parameters for a tetragonally elongated octahedral 3d9cluster. The impurity Cu2+occupying the octahedral sites are found to experience the relative tetragonal elongation ratios of about 11.4% and 9.5% for crystalline TeO2and GeO2and 10.8% and 6.6% for amorphous TeO2and GeO2, respectively, along the C4axis due to the Jahn–Teller effect. This reveals the larger tetragonal elongation distortions for the Cu2+centres in crystalline than amorphous systems (especially TeO2). The theoretical spin Hamiltonian parameters show good agreement with the experimental data. The results are discussed. [ABSTRACT FROM AUTHOR]

Highly efficient fast light propagation of optical pulse at negative group velocity was demonstrated in a single-mode tellurite fiber embedded in a Brillouin laser ring cavity. A maximum advancement of 385 ns and an average time advancement per unit power of 3.77 ns/mW were observed when the cavity was pumped with a 1-MHz sinusoidal wave signal at a power level of 102 mW. Pump loss of 7.9 dB was also monitored at the maximum fast light generation, showing an average slope efficiency of 48.7 ns/dB. [ABSTRACT FROM PUBLISHER]