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1.
Bismuth phosphate glasses of the basic composition (Bi2O3 30 mol%-P2O5 70 mol%) with additional dopants 3d TM oxides (0.2 wt%) were prepared by the melting and annealing technique. Combined optical (UV/vis.) and FT infrared absorption spectra were measured for the prepared samples before and after gamma irradiation with a dose of 8 Mrad (8×104 Gy). Optical spectra reveal strong UV absorption bands due to trace iron impurity together with an additional absorption band due to Bi3+ beside characteristic absorption related to specific 3d TM ions with preference for the lower valences due to the reducing effect of phosphate host glass. FTIR spectra show vibrational bands due to phosphate chains with the sharing of absorption bands due to Bi-O vibrations. Gamma irradiation causes limited changes due to the presence of heavy metal Bi3+ ions which show some shielding behavior towards gamma irradiation as revealed by optical and FT infrared absorption measurements. Some suggested photochemical reactions are forward to interpret the changes in the UV spectra beside the formation of an induced phosphorus oxygen hole center (POHC) in the visible region. 相似文献
2.
Optical absorption spectral investigations have been carried out on Fe 3+ ions doped sodium borate, sodium silicate and sodium phosphate glasses before and after gamma irradiation. The UV-visible absorption spectrum exhibits bands characteristic of Fe 3+ ions coordination in each system. Interesting aspects of FT-IR spectra were found, and this gives information about the structure changes in the constituent units of these glass systems as a function of Fe 2O 3 concentration. All glasses reveal characteristic absorption bands due to the addition of different ratios of iron which explain the state of iron in each system in terms of its valence and coordination number. Results indicate that iron favors a higher oxidation state (tetrahedral coordination) in the case of sodium silicate glasses. The doping with progressive Fe 2O 3 additions (0.5?7.5 %) has some effect on the number and position of the characteristic bands due to formation of FeO 4 groups. The IR absorption spectra after irradiation reveal limited changes in the intensity which can be correlated with minor changes in bond angles and /or bond lengths within the structural units by irradiation. 相似文献
3.
The optical absorption spectra of undoped soda lime silicate glass together with two glasses doped with either (1 % nano Fe 2O 3 ) or with both (1 % Nano Fe 2O 3 + 5 % cement dust) have been measured from 200 to 2400 nm before and after gamma irradiation with a dose of 8 Mrad. The undoped glass reveals strong UV absorption with two distinct peaks which are attributed trace ferric iron ions present as impurity. Upon gamma irradiation , this base glass exhibits three peaks at 240,310 and 340 nm and the resolution of an induced broad visible band centered at 530 nm. The two doped glasses show an additional small visible band at about 440 nm and followed by a very broad band centered at 1050 nm. Upon gamma irradiation, the two doped samples reveal the decrease of the intensities of the spectrum. The two additional bands are related to ferric (Fe +3) ions to the band at (440 nm) while and the broad band at 1050 nm is due to ferrous iron (Fe +2) ions. The decrease of the intensities of the UV-visible spectrum upon irradiation can be related to of capturing freed electrons during irradiation . Infrared spectra of the glasses reveal repetitive characteristic absorption bands of silicate groups including bending modes of Si–O–Si or O–Si–O, symmetric stretching , antisymmetric stretching and some other peaks due to carbonate , molecular water , SiOH vibrations . Upon gamma irradiation, the IR spectra reveal a small change in the base spectrum while the IR spectra of the two doped glasses remain unchanged. The change of the IR spectrum of the base glass is related to suggested changes in the bond angles or bond lengths of the mid band structural units. The doped glasses show resistance to gamma irradiation because the nano Fe 2O 3 can capture released electrons and positive holes. 相似文献
4.
Aluminum oxide nanoparticles (Al 2O 3) were prepared and the obtained structure and size of the prepared Al 2O 3 nanoparticles were studied via X‐ray diffraction (XRD) and transmission electron microscopy. The effect of adding various concentrations of the Al 2O 3 and gamma radiation on the structural and optical properties of syndiotactic polystyrene (sPS) were investigated using XRD and UV‐spectroscopy. XRD data showed that the addition of the various concentrations of the Al 2O 3 influenced the crystallinity of the nanocomposites. A significant change in the lattice structure and the optical parameters were observed. The results showed that a sample with the Al 2O 3 concentration of 10% achieved a higher refractive index and optical conductivity. Effect of gamma irradiation on sPS sample loaded with 10% Al 2O 3 was studied. The results showed several changes in the structure and optical properties of the resulting films due to crosslinking between the polymer chains. This result reflects that the polymer suffered from structural rearrangement due to the irradiation treatments. POLYM. ENG. SCI., 59:555–565, 2019. © 2018 Society of Plastics Engineers 相似文献
5.
Heavy metal oxide glasses (composition 60 PbO, 20 Bi 2O 3 mol%) and containing 20 mol% conventional glass formers SiO 2, B 2O 3, and P 2O 5 were prepared. Combined optical and Fourier transform infrared absorption spectra were measured for the prepared glasses to justify the role of glass formers in the optical spectra together with the network structural groups in such glasses. Also, the density and molar volume values were calculated to obtain some insight on the compactness and arrangement in the network. Optical measurements have been used to determine the optical band gap (E g), Urbach energy (ΔE) and the refractive index (n). Optical spectra of all the samples reveal strong UV absorption which is related to the presence of unavoidable trace iron impurities (Fe 3+ ions) contaminated within the raw materials which were used for the preparation of the studied glasses. Additional near visible bands are observed in all prepared glasses due to characteristic absorption of Pb 2+ and Bi 3+ ions. Furthermore, The variations of the luminescence intensity, values of the optical band gap, band tail, and refractive index can be understood and related in terms of the structural changes that take place in the glass samples. The infrared absorption spectra of the prepared glasses show characteristic absorption bands related to the borate or silicate or phosphate network (BO 3, BO 4, SiO 4, PO 4 groups) together with vibrational modes due to Bi-O and Pb-O groups. 相似文献
6.
The growing demand for radiation-resistant optical glasses for space and nuclear radiation applications has attracted significant research interest. However, radiation-resistant fluorophosphate glasses have been poorly studied. In this work, we report on the tailoring and performance of radiation-resistant fluorophosphate glasses that contained cerium through codoping with Sb 2O 3 and Bi 2O 3. The physical properties, optical properties, microstructure, and defects of fluorophosphate glasses were investigated using transmittance measurements, absorption measurements, as well as Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) spectroscopy. The results showed that the radiation resistance of all codoped fluorophosphate glasses was better than the undoped cerium-containing fluorophosphate glasses after 10–250 krad(Si) irradiation. Especially in glasses doped with Bi 2O 3, the optical density increment at 385 nm was only 0.1482 after 250 krad(Si) irradiation. The CeO 2 prevented the development of phosphate-related oxygen hole center (POHC) defects, whereas further codoping with Bi 2O 3 suppressed the formation of oxygen hole center (OHC) and POEC defects, reducing the breaking of phosphate chains caused by CeO 2. Bi 3+ is more likely than Sb 3+ to change the valence, affecting the transition equilibrium of intrinsic defects and reducing the concentration of defects produced by irradiation. When codoping with Sb 2O 3 and Bi 2O 3, Bi 2O 3 does not enhance radiation resistance owing to the scission effect of Sb 2O 3 on the phosphate chain, which is not conducive to the radiation resistance of glasses. This indicates that the cerium-containing fluorophosphate glasses doped with Bi 2O 3 can effectively suppress the defects caused by irradiation and improve the radiation resistance of the glasses. 相似文献
7.
This study is focused on investigating the role of bismuth oxide (Bi 2O 3) nanoparticles to improve structural, optical, electrical, and mechanical properties of low-density polyethylene (LDPE). For this purpose, Bi 2O 3 nanoparticles were synthesized by using the solvothermal method and examined by transmission electron microscopes (TEM), x-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–Vis) light absorption methods. LDPE-based nanocomposites were prepared by changing the nanoparticle additive ratio in the composite from 0% to 2% by weight. The composites were analyzed in the context of their FTIR spectra, atomic force microscope (AFM) images, UV–Vis light absorption spectra, stress–strain curves, and energy storage abilities. While the AFM findings indicate a smoother surface for the composites, the optical band gap analysis reveals a slightly decreased direct optical band gap energy. The analyses based on dielectric spectroscopy also highlight the LDPE/0.5% n-Bi 2O 3 composite in terms of the best energy storage capability. Additionally, the highest Young's modulus, toughness, stress at break, and percentage of strain at break were also recorded for the LDPE/0.5% n-Bi 2O 3 composite. In this context, the LDPE/0.5% n-Bi 2O 3 composite with improved dielectric and mechanical properties can be suggested as a new promising LDPE-based nanocomposite with better properties for industrial purposes. 相似文献
8.
Optical and FT Infrared spectroscopic measurements have been utilized to investigate and characterize binary bismuth silicate glass together with derived samples by replacements of parts of the Bi 2O 3 by SrO, BaO, or PbO. This study aims to justify and compare the spectral and shielding behavior of the studied glasses containing heavy metal ions towards gamma irradiation. The study also aims to measure or calculate the optical energy band gap of these glasses. The replacements of parts of Bi 2O 3 by SrO, BaO or PbO caused some changes within the optical and infrared absorption spectra due to the different housing positions and physical properties of the respective divalent Sr2+, Ba2+, Pb2+ ions. The stability of both the optical and infrared spectra of the studied bismuth silicate glass and related samples towards gamma irradiation confirm some shielding behavior of the studied glasses and their suitability as radiation shielding candidates. 相似文献
9.
Tb 3+-doped 25Na 2O-23CaO-6P 2O 5-44B 2O 3-2ZrO 2 glass was fabricated by conventional melt-quenching technique. Glass-ceramics containing NaCaPO 4 crystals were then obtained by heating the as-prepared glasses. Their optical and luminescence properties were studied by FT-IR spectroscopy, photoluminescence (PL), absorption spectra, thermoluminescence (TL), and optically stimulated luminescence in continuous wave modality (CW-OSL). The glasses were composed of [PO 4], [BO 3], and [BO 4] basic structural units. The PL excitation and emission spectra exhibited Tb 3+-related transitions, as well as the strongest excitation and emission wavelengths at 370 and 454 nm, respectively. We further investigated the CW-OSL properties as a function of dopant concentration and time elapsed after irradiation (signal fading). Results indicated that the CW-OSL intensity reached a maximum when the Tb 4O 7 concentration was 0.25 mol%. The fading of the OSL signal showed that the OSL signal of Tb 3+-doped NaCaPO 4 glass-ceramics was approximately 65% in 8 days, after which the intensity remained stable. The TL glow curves had a broad peak feature peaking at 180 ± 5ºC. The samples also exhibited good signal reusability and a broad linear dose-response range (0.03-1000 Gy). The excellent luminescent and dosimetric properties of these Tb 3+-doped NaCaPO 4 glass-ceramics indicated their potential applications in radiation dosimetry. 相似文献
10.
In a bid to expand the amount of information available on glass systems and their potential applications for radiation shielding design, glass samples with the compositions (30-x)SrO-xAl 2O 3–68B 2O 3–2V 2O 5(x = 5, 7.5, 10, 12.5&15 mol %) coded as SABV0 - 4 were prepared by the melt-quenching technique and analyzed for their optical, structural, physical, and radiation shielding features. The glassy (amorphous) nature of the SABV glass samples was affirmed by broad peaks of X-ray diffraction spectra. Calculated values of density and molar volume shown opposite behavior and the variation of these values were discussed as structural modifications in the glass matrix. From recorded optical absorption spectra optical band gap energy (Eg)-indirect transition, Urbach energy and optical basicity were estimated. FTIR spectra were recorded for all the samples in the range 400 cm ?1 to 4000 cm ?1. The FTIR absorbance spectra unveiled the SABV network structure mainly incorporating of BO 3 and BO 4 units. Raman spectroscopy is achieved to detect the structural changes and at higher wavenumber, B–O stretching modes in [BO 3] observed with one or two NBO's. The results of ESR spectra of glasses have indicated the highly covalent environment of vanadium ions. Analysis of the photon shielding parameters of the glasses which were obtained primarily from FLUKA Monte Carlo simulations and XCOM computations revealed photon energy and glass chemical composition dependence. The mass attenuation coefficient and effective atomic number ranged from 0.2668 to 0.3385 cm 2g -1 and 12.98–15.93 accordingly as the weight fraction of Sr increased from 16.06 to 26.72% in the glasses. Generally, photon shielding ability of the SABV glasses follows the trend: SABV0 > SABV1 > SABV2 > SABV3 > SABV4. The thermal neutron total cross section follows the same trend with values fluctuating between 71.9553 and 80.6268 cm ?1. However, SABV1 showed superior fast neutron moderating capacity among the glasses. The present SABV glasses showed outstanding photon shielding ability compared to common shields. The prepared glasses are thus suitable candidates for radiation protection applications. 相似文献
11.
High-energy radiation in space and nuclear irradiation environment induces colour centres in optical glass, causing solarisation, and a serious condition can render optical systems and optical loads unusable. To develop space radiation-resistant optical glass, CeO 2-stabilised radiation-hard fluorophosphate glass was prepared under three different atmospheres (nitrogen, oxygen, and ambient air). The glass-melting atmospheres' effects on the glass's transmission, defect formation, and structural changes before and after exposure to gamma radiation were investigated by a comprehensive study on their transmittance, absorption, and electron paramagnetic resonance spectra. Introducing a small amount of CeO 2 (~0.34 wt%) into the fluorophosphate base glass converted NBO and BO into ABO in the glass network, red-shifted the UV absorption edge, and decreased the optical density increment by almost half after radiation. As the total dose of gamma radiation increased, the transmittance of the irradiated glass at a wavelength of 385 nm significantly increased due to absorption of POHC2 defects. After exposure to 250 k of rad gamma irradiation, the corresponding optical density increment per centimeter thickness at 385 nm of the radiation-hard fluorophosphate glass that melted in the nitrogen, oxygen, and air atmospheres decreased from 1.839 to 1.388 and 1.215. As it melted in air, the NBO ratio of the fluorophosphate glass reached the lowest level and the Ce 4+ ratio in the glass was 92.49%, which helped suppress the generation of POHC, Fe 3+, PO 4-EC, and PO 3-EC defects during the gamma irradiation process, improving the glass's radiation resistance. 相似文献
12.
Dy 3 + -doped lead phosphate glasses were prepared by a melt quenching technique and investigated through Infrared absorption spectra (IR), photoluminescence (PL), and UV-Visible optical absorption measurements (UV-Vis). The luminescence spectra show two intense bands at 483 and 575 nm, which are attributed to 4FH 15/2 (blue) and 4FH 13/2 (yellow) transitions, respectively. The optical spectra data was used to evaluate the values of indirect allowed transitions. It was found that the optical band gap increases with Dy 2O 3 content. Variation in optical gap energy with the variation in localized state tails, confirms the theories for localized states in the energy gap of amorphous semiconductors. The characteristic infrared absorption bands of these glasses due to the stretching and bending vibrations were identified and analyzed by the increasing of the Dy 2O 3 content. This fact allowed us to identify the specific structural units which appear in these glasses. 相似文献
13.
Er/Yb co-doped transparent glass ceramics containing nanocrystalline Bi 2ZnB 2O 7 were successfully prepared by a high-temperature melting method. X-ray diffraction analysis confirmed the structural properties of the crystal and glass phases of the glass ceramics. Scanning electron microscope images indicated that nanocrystalline Bi 2ZnB 2O 7 with an average size of 30–40 nm was uniformly distributed in the glass matrix. Infrared spectroscopy demonstrated that the glass and glass ceramics had different vibrational peaks. The absorption spectra showed the absorption peaks of the samples, and the main spectral parameters of each absorption peak were calculated using the Judd–Ofelt theory. The emission spectra of the samples showed ultra-wideband fluorescence from 1400 to 1700 nm under excitation at 980 nm, which was enhanced by precipitation of nanocrystalline Bi 2ZnB 2O 7 and the addition of Yb 3+ ions. Our research showed that Er/Yb co-doped glass ceramics containing nanocrystalline Bi 2ZnB 2O 7 are a promising material for application in near-infrared optical amplifiers. 相似文献
14.
To better understand the structural and optical properties of composite cement/BaSO 4/Fe 3O 4 for various amount of BaSO 4/Fe 3O 4, the X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy have been used to investigate the correlation between their structural and optical properties. The structural properties including crystallite size, micro strain, stress and energy deformation were analyzed from the quantitative analysis of XRD spectra by using size-strain plot (SSP) methods. The refractive index ( n), extinction coefficient ( k), dielectric functions (ε), and energy loss function (Im (−1/ε)) were analyzed from the quantitative analysis of FTIR spectra by using kramers-kronig (K–K) relations. The corresponding structures for high amount of BaSO 4/Fe 3O 4 in composite cement/BaSO 4/Fe 3O 4 become less stable which consistent with the distance between the wavenumber of transversal and longitudinal optical phonon vibration mode become shorter. For all composites cement/BaSO 4/Fe 3O 4 in this study, we found that the distance wavenumber (Δ) between longitudinal optical (LO) and transversal optical (TO) phonon vibration decrease with increasing the crystallite size and linear attenuation coefficient. Our results indicated that the FTIR spectra could be useful for determining the optical phonon vibration, dielectric function, and energy loss function of composite cement/BaSO 4/Fe 3O 4. 相似文献
15.
Multicomponent TeO 2–Bi 2O 3–ZnO (TBZ) glass thin films were prepared using RF magnetron sputtering under different oxygen flow rates. The influences of oxygen flow rate on the structural and optical properties of the resulting thin films were investigated. We observed that thin films sputtered in an oxygen‐rich environment are optically transparent while those sputtered in an oxygen‐deficient environment exhibit broadband absorption. The structural origin of the optical property variation was studied using X‐ray diffraction, X‐ray photoelectron spectroscopy, Raman Spectroscopy, and transmission electron microscopy which revealed that the presence of under‐coordinated Te leads to the observed optical absorption in oxygen‐deficient films. 相似文献
16.
Combined UV-visible and FTIR spectral studies of undoped and Nd 2O 3 –doped sodium silicophosphate glasses were carried out to characterize the optical and structural properties of such glasses. The base undoped silicophosphate glass exhibits strong UV absorption which is due to the presence of unavoidable trace iron impurities (mainly Fe 3+ ions) present contaminated within the raw materials used for the preparation of such glasses. Nd 2O 3 –doped glasses show characteristic absorption bands extending in the entire visible region which are attributed to the contribution of Nd 3+ ions with distinct peaks which are almost constant with the increase of dopant. This comes from the combined compact glass structure containing two glass forming units and the shielding of the rare-earth ions. Infrared absorption spectra of the studied glasses reveal characteristic IR bands due to the combination of both silicate and phosphate groups. The introduction of Nd 2O 3 within the dopant level (2 %) produces no variations in the IR vibrational bands due to the presence of the two structural silicate and phosphate groups giving compactness of the network structure. The deconvoluted spectra reveal the presence of phosphate groups in a slightly high ratio due to the high content of P 2O 5 in the composition. 相似文献
17.
Lead borosilicate glasses, of chemical composition 20SiO 2-xPbO-(15 + x)B 2O 3-5WO 2-10ZnO-(50-2x) Na 2O (where x = 5, 10, 15, 20, 25) were prepared using the normal melt-quenching technique. The samples were examined using a Philips Analytical X-ray diffraction system in order to check their amorphous nature. The effect of increasing B 2O 3 and PbO content on glass transition temperature was examined using Differential Thermal Analysis measurements (DTA). The results of DTA showed that both melting and glass transition temperatures decrease with increase of lead and boron oxides. Density and its related parameters have been determined to study the effect of lead-boron content on the structural properties of the prepared samples. Based on the density and DTA results, the network forming role of Pb and B ions was proved. The optical properties of the glass samples have been obtained using UV-VIS measurements. The optical parameters, such as optical band gap, Urbach energy, refractive index, and electronic polarizability were deduced based on the optical data. The observed increase in optical band gap and decrease in Urbach energy as well as the red shift in the absorption spectra arise due to the formation of non-bridging oxygen. 相似文献
18.
The quaternary glasses of mixed divalent oxides including ZnO, MgO, CdO within a phosphate network former were prepared. Vanadium pentoxide was introduced as a dopant in the range from 0.5 to 3%. Optical and infrared absorption studies for all glass samples were carried out. The optical spectra reveal the presence of both V 3+ and V 4+ ions in the studied host mixed divalent oxides phosphate glass. Fourier transform infrared absorption spectral analysis indicates the appearance of distinct vibrational bands due to the presence of characteristic phosphate groups depending on the glass composition and the ratio of V 2O 5 content. The optical band gap and Urbach energy were calculated and discussed in relation to the effect of V 2O 5 content. Finally, the glasses were optically and structurally examined affter gamma irradiation with a dose of 80 KGy. 相似文献
19.
The specific features of the induced optical absorption spectra of glasses in the 45Na 2O · xNb 2O 5 · (55 ? x)P 2O 5 system with Nb 2O 5 contents x = 5, 10, 20, 25, 30, and 35 mol % are investigated as functions of the irradiation dose and the heat treatment time. The spectra are decomposed into Gaussian components with the use of computer processing. It is revealed that the glass composition and the irradiation dose affect the number, type, and parameters of the bands associated with the PO 4 2? hole-type centers, electron-type color centers of the phosphate matrix, [Nb (5+)?] one-electron centers, and [Nb (5+)?-O-Nb (5+)?] two-electron centers. The inference is made that heat treatment at temperatures close to the glass transition point T g leads to the formation of groupings with a structure similar to structural motifs of NaNbO 3 crystals. It is demonstrated that these groupings are responsible for the induced optical absorption in the near-IR spectral range. 相似文献
20.
This work aimed to evaluate the structural, optical, and physical features of several types of glasses based on 85TeO 2-(15–x)ZnO-xIn 2O 3 (x = 2, 4, 6, and 8 mol%) system. As a result, five different samples were synthesized utilizing the melting-annealing technique. The Archimedes method was used to calculate the densities of the synthesized glasses. The structural, optical, physical, and radiation interaction characteristics of the sample were determined using XRD investigations, Raman spectra, and advanced modelling methods, producing optical band gap, refractive index, and Urbach energy values. The glass densities increased from 5.6091 g cm −3 to 5.6754 g cm −3 by increasing In 2O 3 reinforcement from 2 to 8 mol %. Urbach energies increased consistently from 0.1399 to 0.1439 eV as In 2O 3 concentration increased, apart from a drop to 0.1345 eV at x = 8. The optical transmittance and absorption characteristics altered nearly monotonically with increasing In 2O 3 ratios, showing that these characteristics may be estimated and controlled using In 2O 3 additive. By substituting ZnO with In 2O 3 within the structure, the optical band gap was dramatically enlarged. Additionally, at simulated energies greater than 0.02 MeV, the gamma-ray mass attenuation coefficient grows monotonically with In 2O 3 reinforcement. As a result, it can be stated that the high concentration In 2O 3 to TeO 2–ZnO glass combination is a good synergetic tool for integrating structural, optical, and radiation properties. 相似文献
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