Artykuły w czasopismach: „FTIR Spectra - Network Structure - Glasses”

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Montenero, A., R. A. Condrate i Y. M. Guo. "Structural information concerning the glass network in Bi–Zn–Fe–B–O glasses". Journal of Materials Research 4, nr 3 (czerwiec 1989): 473–75. http://dx.doi.org/10.1557/jmr.1989.0473.

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Fourier transform infrared (FTIR) absorption spectra were measured for various glasses in the Bi–Zn–Fe–B–O system, and interpreted upon the basis of glass structure. Spectral changes were noted with variations in the composition for these glasses that were related to changes in the atomic arrangement of the boron oxide portion of the glass network. The changes in glass transformation temperature with changes in glass composition were discussed in terms of structural data.

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ARDELEAN, I., C. ANDRONACHE, C. CÎMPEAN i P. PǍŞCUŢǍ. "STRUCTURAL STUDY OF x(Fe2O3·V2O5)·(100-x)[P2O5·Li2O] GLASS SYSTEM BY FTIR SPECTROSCOPY". Modern Physics Letters B 20, nr 02n03 (30.01.2006): 105–10. http://dx.doi.org/10.1142/s0217984906009335.

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Glasses of the x( Fe 2 O 3· V 2 O 5)·(100-x)[ P 2 O 5· Li 2 O ] system, with 0≤x≤50 mol %, were prepared and investigated by FTIR spectroscopy in an attempt to determine the local structure of glasses. The interpretation of the obtained IR spectra revealed the presence and the dependence of the local structural units in the studied glasses on the iron and vanadium ions content. The results showed that phosphate units are the main structural units of the glass system and the iron and vanadium ions are located in the network. The increasing of iron and vanadium ions content indicate a gradual decreasing in the number of bridging oxygen ions and an increasing in the number of nonbridging oxygen ions.

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Wang, Fei, Artemis Stamboulis, D. Holland, Shigeki Matsuya i Akari Takeuchi. "Solid State MAS-NMR and FTIR Study of Barium Containing Alumino-Silicate Glasses". Key Engineering Materials 361-363 (listopad 2007): 825–28. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.825.

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The glass based on a 1.5SiO2-Al2O3-0.5P2O5-CaO-0.67CaF2 composition was produced and substituted gradually by barium. The structure of the glasses was studied by multinuclear Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) and Fourier Transform Infrared Spectroscopy (FTIR). It was indicated by 29Si and 31P MAS-NMR spectra that silicon was present as Q4 (4Al) and Q3 (3Al) species and phosphorus was in a Q1 pyrophosphate environment. 29Al MAS-NMR spectra showed that four fold coordinated aluminum Al (IV) was the dominant species with a second peak assigned to octahedral aluminum Al (VI). The 19F spectra suggested that the barium addition caused the formation of Al-F-Ba(n) and F-Ba(n) species. Furthermore, a distribution of silicate network including Si-O-Si stretching (Q4 and Q3) and Si-O-[NBO] (Q3) per SiO4 was reflected by the FTIR study.

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Majhi, M. R., R. Kumar, S. P. Singh i R. Pyare. "Physico-Chemical Properties and Characterization of CaO-Fe₂O₃-P₂O₅ Glass as a Bioactive Ceramic Material". Journal of Biomimetics, Biomaterials and Tissue Engineering 12 (luty 2012): 1–24. http://dx.doi.org/10.4028/www.scientific.net/jbbte.12.1.

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The Aim of this Work Is to Investigate Role of Iron in Calcium-Iron-Phosphate Bioglass. the Density, Compressive Strength, Tg Point and Leachability of Cations Were Measured. the Ph Behaviour of Simulated Body Fluid after Soaking Phosphate Glasses for Different Time Periods Were Also Studied and it Was Observed that Higher Phosphate Glasses Containing Lower Lime Possessed Better Bioactivity than Lower Phosphate Glasses Containing More Iron and Lime Contents. the DTA and FTIR Spectrometry of Glasses Were Performed. the Absorption Spectra Showed that Iron Was Present in the Glass only as Fe3+ Ion. the Leachability of Ca2+ and Fe3+ Ions from Glass Was due to Diffusion Control and P5+ Ion due to Network Break down of PO4 Tetrahedra. the DTA Peaks Were Broad. the FTIR Band around 1000 Cm-1 in Glass Was due to Asymmetric Stretching of O=P=O Linkage. the FTIR Absorption and Reflectance Spectrometry of the Glass Samples after SBF Treatment Had Confirmed the Deposition of Bone-Like Hydroxyl Carbonate Apatite Layer on the Glass Surfaces for their Bioactivity. the Bands Centred in between 2880-3425 Cm-1 Were due to Presence of OH Groups and Stretching Modes of H-O-H Vibration in Glasses. the Properties and Structure Relationship for Glasses Were Established and the Results Were Discussed.

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Veeranna Gowda, Vijaya Chikkaveeraiah, K. R. Sardar Pasha, M. Sudhakar Reddy i C. Narayana Reddy. "Optical Properties and Structural Studies on Nd³⁺Doped Borate Glasses Containing Heavy Metal Oxide". Advanced Materials Research 584 (październik 2012): 207–11. http://dx.doi.org/10.4028/www.scientific.net/amr.584.207.

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Abstract. Neodymium doped sodium bismuth borate (Na2O-Bi2O3-B2O3) glasses were prepared by melt quenching method. Amorphous nature of the glass is confirmed through the X-ray diffraction study. Density of the investigated glasses increases systematically with Bi2O3 concentration. Glass transition temperature decrease slightly with increase of Bi2O3 content and could be due to increase in the number of weaker Bi-O linkages by stronger Nd-O linkages. Fourier Transform - Infrared (FTIR) spectroscopy has been carried out. The IR spectra of the glasses reveal that the strong network consisting of diborate units and is unaffected by the variation of Nd3+ concentration. UV-Visible absorption studies have been performed on these glasses to examine the optical spectra and the optical band gap energy has been calculated. The intensity of the absorption band increases with the increase of Nd3+ concentration. This is due to the formation of non-bridging oxygens (NBO’s) in the structure.

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Subashini, C., R. Ezhil Pavai i L. Balu. "Effect of Pb2+ Ions on the Mechanical, Structural and Thermal Behaviour of B2O3-CaO Glasses". Asian Journal of Chemistry 32, nr 1 (18.11.2019): 101–5. http://dx.doi.org/10.14233/ajchem.2020.22337.

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B2O3-CaO-PbO glasses with different concentrations of PbO (5-20 mol % in four steps) were prepared by melt quench technique. The amorphous nature and homogeneities of the prepared glasses were confirmed by XRD and SEM analyses. Ultrasonic velocities and density were measured at 303 K using pulse-echo technique and Archimedes’ principle respectively. Various parameters, viz., molar volume, longitudinal modulus, shear modulus, bulk modulus, Young’s modulus, Poisson’s ratio, micro-hardness and Debye temperature have been evaluated from the measured data. The results of ultrasonic properties indicate that the incorporation of lead ions expand the calcium borate network structure. FTIR spectra revealed that boron exists in both trigonal and tetrahedral structural units and no boroxial ring formation takes place in the glass structure. The transition temperature, melting temperature and crystallization temperature have been identified using DTA measurements.

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Feike, M., K. Meise-Gresch, Qi Chen i G. H. Frischat. "NMR and FTIR Characterization of Sol-Gel Derived Ternary Oxide Glasses in the System BaO–TIO2–SiO2". Zeitschrift für Naturforschung A 50, nr 9 (1.09.1995): 837–44. http://dx.doi.org/10.1515/zna-1995-0908.

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Abstract The annealing history of glasses in the system (20-40) BaO-40TiO2(40-20)SiO2 has been monitored by 29Si MAS NMR and FTIR spectroscopy from the dried gel to the final glassy state. Assignment of chemical shifts to specific building units has been facilitated by comparative studies of the limiting less complex binary silicate systems. From the NMR spectra at various compositions appreciable condensation to a three-dimensional network is inferred already at low drying temperatures. Processes like the pyrolysis of acetate rests of the starting materials and modification of the silicate structure due to Ba2+ cations have been mirrored in the spectra of both methods for samples annealed at intermediate temperatures. The microstructure of the final gel glass of the ternary system has been determined spectroscopically to consist of silicate and titanate species typical of crystalline fresnoite, whereas remaining amounts of TiO2 and SiO2 develop a separate network each. Only small amounts of Si-O-Ti linkages have been recognized in the vibrational absorptions; they vanish at higher annealing stages.

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PAL SINGH, GURINDER, PARVINDER KAUR, SIMRANPREET KAUR, DEEPA WALI ARORA, MOHANDEEP SHARMA i D. P. SINGH. "EFFECT OF ALUMINIUM IONS ON COVALENT BEHAVIOUR OF Li2CO3-B2O3 GLASSES". International Journal of Modern Physics: Conference Series 22 (styczeń 2013): 313–20. http://dx.doi.org/10.1142/s2010194513010283.

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The paper undertakes the preparation of Aluminium oxide doped Lithium borate glasses and characterizes to investigate the physical and optical studies of these glasses using density and UV-Visible spectroscopy. Results had been obtained with the help of FTIR Spectra in our previous work which indicate that Al2O3 acts as a network modifier by converting three coordinated boron atoms [ BO3 ] to four coordinated boron atoms [ BO4 ]. The effect of aluminium content on the optical properties of the present glass system has been studied from the optical absorption spectra. It shows the shifting of the band edge towards the higher wavelength and that there is corresponding decrease in the band gap, which is due to the conversion of BO3 to BO4 units. The evaluation of the compact structure of prepared glass samples with the presence of [ BO4 ] groups has been made in terms of the physical properties such as density and molar volume. It is also confirmed by average boron-boron separation results. The research findings confirm that the addition of Aluminium oxide increases the covalent value and corresponding decrease in ionicity behaviour.

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Mostafa, Ahmed M. A., Mohamed A. M. Uosif, Ziyad A. Alrowaili, Reda Elsaman, Ahmed A. Showahy, Yasser B. Saddeek, Shams A. M. Issa, Antoaneta Ene i Hesham M. H. Zakaly. "The Influence of CoO/P2O5 Substitutions on the Structural, Mechanical, and Radiation Shielding of Boro-Phosphate Glasses". Materials 14, nr 21 (3.11.2021): 6632. http://dx.doi.org/10.3390/ma14216632.

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A new glass system (50−x)P2O5–20B2O3–5Al2O3–25Na2O–xCoO was manufactured using a standard melt quenching procedure, where 1≤ x ≤ 12 mol%. The characteristics of boro-phosphate-glasses containing CoO have been studied. The effect of CoO on the radiation-protective properties of glasses was established. The density of the prepared glasses as a function of CoO increased. XRD was used to check the vitreous structure of samples. Fourier-transform infrared (FTIR) spectroscopy was used to study the structure of each sample. FTIR demonstrated that connections grew as CoO/P2O5 levels increased, and the FTIR spectra shifted to higher wavenumbers. The increment of CoO converts non-bridging oxygens associated with phosphate structural units into bridging oxygens. This process increases the concentration of BO4 structural units and creates new, strong and stable bonds B–O–P, i.e., there is polymerization of the boro-phosphate glass network. With an increase in the ratio of CoO/P2O5 in the produced samples, ultrasonic velocities and elastic moduli were observed to increase. The coefficients of linear and mass attenuation, the transmittance of photons in relation to the photon energy, the efficiency of radiation protection in relation to the photon energy, and the thickness of the absorber were modeled using these two methods (experimental and theoretical). From the obtained values, it can be concluded that the 12Co sample containing 12 mol% will play the most influential role in radiation protection. An increase in the content of cobalt-I oxide led to a significant increase in the linear and mass attenuation coefficient values, which directly contributes to the development of the radiation-protective properties of glass.

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Anigrahawati, Puzi, i Md Rahim Sahar. "Structural Properties of Erbium Doped Tellurite Glass Embedded with Natural Ferrite Oxide Nanoparticles". Solid State Phenomena 268 (październik 2017): 177–80. http://dx.doi.org/10.4028/www.scientific.net/ssp.268.177.

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Natural ferrite oxide nanoparticles (NPs) embed with tellurite glasses ((89-x) TeO2-10ZnO-1Er2O3-(x)Fe3O4, (x = 0 – 0.8 mol %)) were prepared by conventional melt quenching method to study the influence of the Fe3O4 NPs concentration on the stuctural properties of the glass. Studies on these glassy materials characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and RAMAN spectroscopic measurements are presented. It is observed that the amorphous nature of the glass is confirmed by x-ray diffraction. The FTIR studies support the formation of Te-O-Fe linkages. The FTIR spectra reveal modification in network structures evidenced from vibrational wave-number shifts of TeO4 and TeO3 structural units. Raman spectroscopy have been manipulated to observe the structural modification of [TeO4] trigonal bipyramidal structural unit.

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Amat, Azuraida, Halimah Mohamed Kamari, Che Azurahanim Che Abdullah, Mansor Ishak, Shahrim Mustafa Iskandar i Sidek Abdul Aziz. "Optical Properties Changes of Ternary Glasses: Gamma Irradiation Effect". Materials Science Forum 840 (styczeń 2016): 118–23. http://dx.doi.org/10.4028/www.scientific.net/msf.840.118.

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Research on tellurite based glass has become important because of it potential in photonic and shielding material. In this work, the changes of the optical properties of ternary tellurite glasses when radiated with 25kGy gamma ray dose were studied. Five glass samples, with composition [(TeO2)70 (B2O3)30]100-x (Bi2O3)x (where x = 5, 10, 15, 20 and 25 mol%) were prepared by melt quenching technique. The optical properties were studied by UV-Visible absorption. The X-Ray Diffraction (XRD) spectra result shows that all glass samples fit the amorphous state. The Fourier Transform Infrared Spectroscopy (FTIR) was used to explore the structural bonding in the prepared glass samples due to exposure. Gamma irradiation causes a profound change in the peak intensity as shown by FTIR spectra which is due to the breaking of the network bonding. Before gamma irradiation, the optical band gap, Eg value decreased from 2.50 eV to 2.30 eV with the addition of Bismuth content. The value kept decreasing (from 2.18 eV to 2.05 eV) following exposure to 25 kGy gamma irradiation due to the increase of non-bridging oxygen (NBO) and the increase of defect in the glass. The finding suggest that the glass with high content of Bi2O3 (25 Bi) give smallest Eg and show less changes (less defect) in FTIR spectra after gamma irradiation which indicate that this glass is more resistant to 25 kGy gamma irradiation dose compared to other glasses.

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Abdel‐Kader, A., R. El‐Mallawany i M. M. ElKholy. "Network structure of tellurite phosphate glasses: Optical absorption and infrared spectra". Journal of Applied Physics 73, nr 1 (styczeń 1993): 71–74. http://dx.doi.org/10.1063/1.354064.

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Samdani, Md Shareefuddin, G. Ramadevudu, S. Laxmi Srinivasa Rao i M. Narasimha Chary. "Physical, Optical, and Spectroscopic Studies on MgO-BaO-B2O3 Glasses". ISRN Ceramics 2013 (24.12.2013): 1–11. http://dx.doi.org/10.1155/2013/419183.

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The mixed alkaline effect in double alkaline borate glasses MgO-BaO-B2O3 containing small proportions of copper oxide (CuO) has been studied. The glass samples are characterized by optical absorption, electron paramagnetic resonance (EPR), and Fourier transform infrared spectroscopy (FTIR). A red shift in optical absorption peaks with increasing MgO (decreasing BaO) concentration has been observed. The values of “g” tensor and hyperfine “A” tensor have shown inflections with glass composition. The number of spins (N) and paramagnetic susceptibility (χ) also exhibited mixed alkaline effect. The broadening of glass network with increase in MgO concentration is found from the FTIR spectra. Interestingly both density and molar volume have shown decreasing trend with glass composition. The optical band gaps exhibited a nonlinear compositional dependence. As expected, the glass samples possessed higher values of optical basicity (Λ), molar electronic polarizability (αm), and Urbach energy (ΔE).

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Herrmann, Andreas, Mohamed Zekri, Ramzi Maalej i Christian Rüssel. "The Effect of Glass Structure on the Luminescence Spectra of Sm3+-Doped Aluminosilicate Glasses". Materials 16, nr 2 (6.01.2023): 564. http://dx.doi.org/10.3390/ma16020564.

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Peralkaline Sm3+-doped aluminosilicate glasses with different network modifier ions (Mg2+, Ca2+, Sr2+, Ba2+, Zn2+) were investigated to clarify the effect of glass composition and glass structure on the optical properties of the doped Sm3+ ions. For this purpose, the Sm3+ luminescence emission spectra were correlated with the molecular structure of the glasses derived by molecular dynamics (MD) simulations. The different network modifier ions have a clear and systematic effect on the peak area ratio of the Sm3+ emission peaks which correlates with the average rare earth site symmetry in the glasses. The highest site symmetry is found for the calcium aluminosilicate glass. Glasses with network modifier ions of lower and higher ionic radii show a notably lower average site symmetry. The symmetry could be correlated to the rare earth coordination number with oxygen atoms derived by MD simulations. A coordination number of 6 seems to offer the highest average site symmetry. Higher rare earth coordination probabilities with non-bridging oxygen result in an increased splitting of the emission peaks and a notable broadening of the peaks. The zinc containing glass seems to play a special role. The Zn2+ ions notably modify the glass structure and especially the rare earth coordination in comparison to the other network modifier ions in the other investigated glasses. The knowledge on how glass structure affects the optical properties of doped rare earth ions can be used to tailor the rare earth absorption and emission spectra for specific applications.

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Hasim, Nurhafizah, Md Supar Rohani i Md Rahim Sahar. "Structural Characteristics of Er³⁺ and Nd³⁺ Doped Lithium Niobate Tellurite Glass". Materials Science Forum 846 (marzec 2016): 126–30. http://dx.doi.org/10.4028/www.scientific.net/msf.846.126.

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Optimizing the rare earth doping in inorganic binary glasses for tuneable structural and optical properties is ever-demanding for lasing glass. A series of Er3+ and Nd3+ doped lithium niobate tellurite glasses with compositions of (70-x-y)TeO2–15Li2CO3–15Nb2O5–(x)Er2O3–(y)Nd2O3, where x = 0.0, 1.0 mol % and 0 ≤ y ≤ 1.0 mol% are synthesized using melt-quench technique. Influence of Nd3+ ion concentrations on physical and optical behaviour is examined. X–Ray diffraction pattern confirm the amorphous nature of glasses. The strong dependence of spectral properties on rare-earth dopant indicates the alteration in structures and bonding of glass network. The structural properties of the glass represented by the FTIR spectrum indicate that as Nd2O3 content increases, the sharp infrared absorption peaks are shifted from 474.7 cm-1 to 499.4 cm-1. These peaks are due to Nb-O, Te-O-Te and O-Te-O bond linkage bending vibrations. For TeO4 trigonal bipyramid, the peak occurred at 676.5 cm-1 whereas for TeO3 trigonal pyramid, two infrared band peaks are found at 787.5 cm-1 and 887.6cm-1, respectively. The absorption peaks around 1382.7 cm-1 is due to the Te – O – Nb stretching vibration while peaks at 1635.5cm-1 and 3411.7 cm-1 are due to the stretching vibrations of the hydroxyl group participating in the strong metal bonding as well as in the hydrogen bonding, respectively.

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Stefanovsky, S. V., O. I. Stefanovsky, M. I. Kadyko, V. A. Zhachkin i L. D. Bogomolova. "The Effect of Electron Irradiation on the Structure of Sodium Aluminum-Iron Phosphate Glasses". MRS Advances 1, nr 63-64 (2016): 4227–32. http://dx.doi.org/10.1557/adv.2017.213.

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ABSTRACTGlasses of the series (mol.%) 40 Na2O, (20-x) Al2O3, x Fe2O3, 40 P2O5 were irradiated with 8 MeV electrons to doses equivalent of 0.1, 0.5, and 1.0 MGy and characterized by FTIR spectroscopy and ESR at room temperature. FTIR spectra of all the glasses consist of strong bands due to O-P-O stretching modes in (PO4)3- and (P2O7)4- units at 1000-1200 cm-1, P-O-P stretching modes at 900-950 cm-1 (νas) and 700-750 cm-1 (νs), and bending modes in the PO4 units. The wavenumber range lower 800 cm-1 has some contribution due to stretching modes in MO4 and MO6 (M = Al, Fe) units. Moreover the bands at 3300-3700 cm-1 and 1550-1650 cm-1 due to stretching and bending modes in both absorbed and structurally bound H2O molecules were present. As irradiation dose increases the bands due to stretching and bending modes in water molecules and M-O-H bonds become stronger and are split. No essential changes with increasing dose were observed within the spectral range of stretching modes of the O-P-O and P-O-P bonds. Irradiation yields phosphorus-oxygen hole centers - PO42- (D5) and PO42- (D6), and PO32- ion-radicals (D2) observable in ESR spectra of low-Fe glasses. At x>5 their responses are overlapped with strong broad line due to Fe(III). On the whole, with the increase in iron content the glass structural evolution decrease.

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Lu, S. M., X. M. Yuan, X. H. Zhang, Y. J. Cui, H. T. Wu i Y. L. Yue. "Effects of CeO₂ Additions on the Structure and Dielectric Properties of Aluminoborosilicate Glasses". Advanced Materials Research 710 (czerwiec 2013): 132–35. http://dx.doi.org/10.4028/www.scientific.net/amr.710.132.

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Glasses with compositions 15Al2O3-20B2O3-50SiO2-5CaO-(10-x)MgO-xCeO2 (x=0, 1, 2 and 3 mol %) were prepared by conventional melting method. Fourier-transform infrared spectroscopy (FTIR) indicated that the addition of CeO2 converted trigonal boron ([B) to tetrahedral boron ([B). The glass transition temperatures (Tg) were determined using a differential scanning calorimetry (DSC). Tg increased with increasing CeO2 content. Thus, the addition of CeO2 instead of MgO strengthened the glass network. The dielectric constant εr and loss tanδ were measured for these glasses at 105 Hz. The decrease in εr and tanδ could be attributed to the increase in the rigidity of the glass network as the CeO2 content increased.

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Hooda, J., R. Punia, R. S. Kundu, Sunil Dhankhar i N. Kishore. "Structural and Physical Properties of ZnO Modified Bismuth Silicate Glasses". ISRN Spectroscopy 2012 (30.12.2012): 1–5. http://dx.doi.org/10.5402/2012/578405.

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Zinc bismuth silicate glasses with compositions 40SiO2·xZnO·(60-x)Bi2O3 (x=0,5,10,15,20,25,30,35, and 40) have been prepared by conventional melt-quench technique and the solubility limit of zinc in bismuth silicate glass system has been estimated using X-ray diffraction technique. Density has been measured using Archimedes' principle; with increase in ZnO in the samples, the molar volume and density are found to decrease. The glass transition temperature (Tg) has been determined by using differential scanning calorimetry (DSC) and is observed to increase with increase in ZnO content. Raman and FTIR spectra have been recorded at room temperature and the analysis of Raman and FTIR shows that in all the glass compositions, asymmetric and symmetric stretched vibrations of Si–O bonds in SiO4 tetrahedral units exist and with decrease in Bi2O3, the contribution of symmetric vibrations begins to dominate which results in increased compactness of the glass structure.

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Saddeek, Yasser B. "Network structure of molybdenum lead phosphate glasses: Infrared spectra and constants of elasticity". Physica B: Condensed Matter 406, nr 3 (luty 2011): 562–66. http://dx.doi.org/10.1016/j.physb.2010.11.041.

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Yuan, X. M., S. M. Lu, X. H. Zhang, Y. J. Cui, H. T. Wu i Y. L. Yue. "Effects of CaO Additions on the Structure and Dielectric Properties of Aluminoborosilicate Glasses". Advanced Materials Research 710 (czerwiec 2013): 127–31. http://dx.doi.org/10.4028/www.scientific.net/amr.710.127.

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Glasses with compositions xCaO-(60-x)SiO2-5MgO-15Al2O3-20B2O3 (x=0, 3, 6 and 9 mol %) were prepared by conventional melting method. Fourier-transform infrared spectroscopy (FTIR) indicated that the addition of CaO converted trigonal boron ([B) to tetrahedral boron ([B). The glass transition temperatures (Tg) were determined using a differential scanning calorimetry (DSC). Tg increased with increasing CaO content. Thus, the addition of CaO instead of SiO2 strengthened the glass network. The dielectric εr and loss tanδ were measured for the MgO-B2O3-Al2O3-SiO2 glass system in the frequency range 103-105 Hz. The decrease in εr and tanδ could be attributed to the increase in the rigidity of the glass network.

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Mošner, Petr, Ladislav Koudelka, Josef Jirák i Miroslav Vlček. "Study of Lithium-Lead Phosphate and Borophosphate Glasses". Advanced Materials Research 39-40 (kwiecień 2008): 181–84. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.181.

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Lithium-lead phosphate and borophosphate glasses were studied in compositional series of xLi2O-(50-x)PbO-50P2O5, xLi2O-(50-x)PbO-10B2O3-40P2O5 and xLi2O-(50-x)PbO-20B2O3- 30P2O5. All glasses crystallize on heating within the range of 400-610oC. Their glass transition temperature decreases with increasing Li2O content in the region of x = 0-30 mol% Li2O and then slowly increases in all series of glasses reflecting thus changes in the bond strength of the glass structural network. Density, molar volume and chemical durability of the glasses decrease with increasing Li2O content. The 31P MAS NMR and Raman spectra show that at all glass series with the replacement of PbO by Li2O the ratio of Q2/Q1 units, present in the structure, slightly increase. The 11B MAS NMR spectra of glasses with 10 mol% B2O3 reveal the presence of only BO4 units in the glass structure, whereas the spectra of the glasses with 20 mol% B2O3 reveal also the presence of small amount of BO3 units.

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Ciang, H. Y., S. M. Hsu, S. W. Yung, Y. J. Chen, C. H. Lin, C. H. Hsu, J. S. Lin i J. Lin. "Properties and Structure Investigation of Rare Earth-Doped Zinc Aluminum Silica-Phosphate Glasses". Advanced Materials Research 509 (kwiecień 2012): 150–51. http://dx.doi.org/10.4028/www.scientific.net/amr.509.150.

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This study explores a series of optical, thermal, and structural properties based on zinc-aluminum phosphate glasses that doped with varied rare earth (RE) elements Yb2O3 and P2O5 components replaced by SiO2. It was found that for 60P glasses system, 7 mol% Yb2O3 doped has the maximum fluorescence but quenching when Yb2O3 is doped up to 9 mol%. In addition, with increasing the content of Yb2O3 the absorption intensity increased. According to Raman spectra, we found the Yb3+ and Si4+ ions for the impact of network structure of glass, SiO2 added to make the network structure of phosphate glasses at 450-500cm-1 and 600-650cm-1 were formed O-T-O bond and T-O-T bond(T=Si, Al).

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Rajagukguk, Juniastel, Donna Helen Rajagukguk, Rahel Suryani Gultom, Pintor Simamora, Rappel Situmorang i Chayani Sarumaha. "Structure and emission properties of Nd³⁺ doped oxyfluorophosphate glasses". Journal of Physics: Conference Series 2193, nr 1 (1.02.2022): 012007. http://dx.doi.org/10.1088/1742-6596/2193/1/012007.

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Abstract The characterization of the phosphate glass system doped by the active ion Neodymium (Nd3+) has been carried out using the Melt-Quenching method. The composition of the phosphate glass is made according to the chemical formula 64P205-20Li20-15X-1Nd203 (X = CaF2 and TeO2). Testing of the physical properties of glass is carried out using the Archimedes method. Testing the structural properties of glass using X-Ray Diffraction (XRD) and Fourier-transformed infrared (FTIR). Testing the optical properties of the glass using a UV-Vis spectrophotometer. XRD results show the glass made has an amorphous structure. The FTIR results show that absorption bands occur in the area of 710-772 cm−1, 871-890 cm−1, 990-1020 cm−1,1074-1157 cm−1, and 1240-1255 cm−1. The results of physical testing showed that the glass density increased and the molar volume decreased with the addition of CaF2 and TeO2 compounds. The highest absorption spectrum is at the transition 4I9/2 → 4G5/2 + 2G7/2 at a wavelength of 582 nm. The lowest direct and indirect bandgap energies are owned by PLTNd (use TeO2) glass, namely 3.30 eV and 3.85 eV. The highest emission spectra are in the two emission band transitions 4F3/2 → 4I11/2 and 4F3/2 → 4I13/2 with wavelengths of 1063 nm and 1334 nm. The highest emission spectrum is produced by PLCNd (use CaF2) glass.

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Hering, Joachim A., Peter R. Innocent i Parvez I. Haris. "An alternative method for rapid quantification of protein secondary structure from FTIR spectra using neural networks". Spectroscopy 16, nr 2 (2002): 53–69. http://dx.doi.org/10.1155/2002/503989.

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Lack of reliable methods for accurate estimation of protein secondary structure from infrared spectra of proteins is a major barrier in its widespread use in protein secondary structure characterisation. Here we report a method for protein secondary structure estimation, from FTIR spectra of proteins, based on a multi‒layer feed‒forward neural network approach using an enhanced “resilient backpropagation” learning algorithm. The method utilises a database consisting of infrared spectra of 18 proteins, with known X‒ray structure, as the reference set. Our study revealed that providing the neural network analysis with only part of the amide I region from empirically determined structure sensitive regions in combination with appropriate pre‒processing of the spectral data produced the best overall results. This lead to a standard error of prediction (SEP) of 4.47% forα‒helix, an SEP of 6.16% forβ‒sheet, and an SEP of 4.61% for turns. Compared to a previous factor analysis study by Lee et al., using the same set of 18 FTIR spectra of proteins, the error in prediction of α‒helix and β‒sheet was improved by 3.33% and 3.54% respectively, with minor increase for turns by 0.31%. Generally, our neural network analysis achieved comparable, in most cases even better prediction accuracy than most of the alternative pattern recognition based methods that were previously reported indicating the significant potential of this approach.

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El-Damrawi, G., D. Shosha, A. M. Abdelghany i M. I. Abdelghany. "Structure and properties of strontium phosphate glasses modified with aluminum oxide applied as glass ionomer cement". Bulletin of the Chemical Society of Ethiopia 37, nr 3 (6.03.2023): 653–62. http://dx.doi.org/10.4314/bcse.v37i3.9.

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ABSTRACT. Studied glasses in the system 50P2O5-(49-x)SrO-1AlF3-xAl2O3 (mol%), 0≤x≤4.5, were prepared via the melt-annealing technique. The prepared samples are transparent amorphous network structures. Glasses are still transparent upon the heat treatment at 540 ºC for 4 hours. 27Al nuclear magnetic resonance (NMR) has been applied to determine the structural role of Al2O3. X-ray diffraction (XRD), Fourier transform infrared (FTIR), and Vickers hardness (Hv) measurements have been carried out. XRD spectroscopy is used to investigate the glasses' crystalline features. The crystallinity was enhanced via the heat treatment process. Some of investigated strontium phosphate glasses are recommended to be applied in dental applications. KEY WORDS: NMR, Aluminum oxide, GIC, X-ray diffraction, Strontium phosphate Bull. Chem. Soc. Ethiop. 2023, 37(3), 653-662. DOI: https://dx.doi.org/10.4314/bcse.v37i3.9

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Noranizah, A., K. Azman, H. Azhan, E. S. Nurbaisyatul i Mardhiah Abdullah. "FTIR and UV-Vis-NIR Spectral Studies of Borotellurite Glass". Advanced Materials Research 1107 (czerwiec 2015): 391–96. http://dx.doi.org/10.4028/www.scientific.net/amr.1107.391.

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A glass system based on composition of 80TeO2-(10-x) B2O3 -10PbO-xNd2O3, where 0.0mol% ≤ x ≥ 2.5mol% was successfully prepared by melt-quenching method. The structural and optical behavior of the Nd3+ doped borotellurite glasses are well studied by mean of their FTIR, XRD as well as UV-Vis -NIR spectroscopy. The XRD pattern obtained confirms the amorphous nature of the glass. Meanwhile, the infra-red absorption spectra of glass samples obtained are recorded using an FTIR spectrometer in the wave number ranging from 400 to 4000 cm-1. The bands observed were attributed to the different modes of vibrations of Te-O band. From the absorption spectral measurements, the value of optical band gap (Eopt) and the Urbach energy (ΔE) values were calculated with the results were then been discussed nor reported. Quantitative justification of these absorption bands shows that the values of the experimental wave number for most absorption bands are in agreement with the theoretical ones. Optical absorption spectra show that the absorption edge has a tail extending towards lower energies. In general, an increment or a decrement in Urbach’s energy can be considered to be due to a deformation of glass network.

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Naruphontjirakul, Parichart. "Sol-Gel Derived Bioactive Glasses as Synthetic Bone Substitutes". Materials Science Forum 1090 (31.05.2023): 31–37. http://dx.doi.org/10.4028/p-pz8o6v.

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Bioactive glasses based on the SrBGs: 45SiO2 - 6P2O5 - 15SrO - 34CaO, 5Zn-SrBGs (wt.%): 45SiO2 - 6P2O5 - 15SrO - 29CaO - 5ZnO (wt.%), and 5Ce-SrBGs: 45SiO2 - 6P2O5 - 15SrO - 29CaO – 5CeO (wt.%) were successfully synthesised through the sol-gel process under the acid condition. The concentration of nitric acid at 0.01M was an optimal condition to accelerate the hydrolysis and polycondensation reactions in these systems. SEM images showed the primary particle nucleus growth in the morphological structure of the SrBGs, 5Zn-SrBGs, and 5Ce-SrBGs. FTIR spectra indicated the incorporation of therapeutic cations in the glass structure whilst maintaining the morphological structure. XRD and SEM suggested the crystalline apatite formation on the surface of BGs after the BGs were incubated in the simulated body fluid (SBF) at pH 7.4 for 21 days. EDS-SEM indicated the apatite formation whilst containing doping ions in the glass structure. All three BGs formulations could promote the murine pre-osteoblast cell (MC3T3-E1) cell proliferation at the concentration between 200-250 µg/mL and have no in vitro cytotoxicity on MC3T3-E1 cells up to the concentration of 1mg/mL.

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SIMON, V., H. BAKO-SZILAGYI, M. NEUMANN, S. G. CHIUZBĂIAN i S. SIMON. "ATOMIC ENVIRONMENT IN LEAD-BISMUTHATE GLASSES CONTAINING MANGANESE". Modern Physics Letters B 17, nr 07 (20.03.2003): 291–301. http://dx.doi.org/10.1142/s0217984903005184.

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The atomic environment of 20MnO · 80(x Bi 2 O 3 · y PbO ) glass samples having the ratio of bismuth to lead atoms of 8:1 and 3:1 was investigated with respect to the thermal induced structural changes, cationic field strength and electronic structure of the compound. The position and full width at half maximum of X-ray photoelectron peaks were estimated using spectra simulation based on the summation of Lorentzian and Gaussian functions. Data obtained from XPS core-level spectra Bi 4f, Pb 4f, Mn 2p, and O 1s indicate a reduction of glass disorder both by heat treatment and by increasing the PbO content in the samples. The cations behave essentially as network formers that could be correlated with an intermediate range structure.

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Yang, L., G. J. Zhou i C. G. Lin. "Composition-dependent properties and network structure of Ge-Se-Te chalcogenide glasses". Chalcogenide Letters 20, nr 1 (styczeń 2023): 1–9. http://dx.doi.org/10.15251/cl.2023.201.1.

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Ge12.5Se87.5-xTex (0≤x≤45) glasses were selected for elucidating the composition-dependent properties and network structure of Te-containing glasses. With increasing Te content (x), Vickers hardness (Hv) and glass transition temperature (Tg) initially increased and then decreased, showing a compositional threshold at x=27.5. It is found that the compositional trend of Hv and Tg is in good accordance with the structural evolution studied by Raman spectra. The results suggest that the introduction of Te leads to the evolution of the network connectivity and average bond strength of Ge12.5Se87.5-xTex glass structure, which imposes an opposite impact on the structural properties (Hv and Tg). This work provides a new insight to the structure-property correlation of Ge-Se-Te, which would facilitate the understanding of the structural role of Te in ChGs.

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Renlund, Gary M., Svante Prochazka i Robert H. Doremus. "Silicon oxycarbide glasses: Part II. Structure and properties". Journal of Materials Research 6, nr 12 (grudzień 1991): 2723–34. http://dx.doi.org/10.1557/jmr.1991.2723.

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Silicon oxycarbide glass is formed by the pyrolysis of silicone resins and contains only silicon, oxygen, and carbon. The glass remains amorphous in x-ray diffraction to 1400 °C and shows no features in transmission electron micrographs (TEM) after heating to this temperature. After heating at higher temperature (1500–1650 °C) silicon carbide lines develop in x-ray diffraction, and fine crystalline regions of silicon carbide and graphite are found in TEM and electron diffraction. XPS shows that silicon-oxygen bonds in the glass are similar to those in amorphous and crystalline silicates; some silicons are bonded to both oxygen and carbon. Carbon is bonded to either silicon or carbon; there are no carbon-oxygen bonds in the glass. Infrared spectra are consistent with these conclusions and show silicon-oxygen and silicon-carbon vibrations, but none from carbon-oxygen bonds. 29Si-NMR shows evidence for four different bonding groups around silicon. The silicon oxycarbide structure deduced from these results is a random network of silicon-oxygen tetrahedra, with some silicons bonded to one or two carbons substituted for oxygen; these carbons are in turn tetrahedrally bonded to other silicon atoms. There are very small regions of carbon-carbon bonds only, which are not bonded in the network. This “free” carbon colors the glass black. When the glass is heated above 1400 °C this network composite rearranges in tiny regions to graphite and silicon carbide crystals. The density, coefficient of thermal expansion, hardness, elastic modulus, index of refraction, and viscosity of the silicon oxycarbide glasses are all somewhat higher than these properties in vitreous silica, probably because the silicon-carbide bonds in the network of the oxycarbide lead to a tighter, more closely packed structure. The oxycarbide glass is highly stable to temperatures up to 1600 °C and higher, because oxygen and water diffuse slowly in it.

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ZHANG, XUEHONG, ZHAO DU, HAITAO WU i YUNLONG YUE. "EFFECT OF TiO2 ON STRUCTURE AND DIELECTRIC PROPERTIES OF RO-Al2O3-B2O3-SiO2(R = Ca, Mg) GLASSES". Surface Review and Letters 20, nr 03n04 (sierpień 2013): 1350030. http://dx.doi.org/10.1142/s0218625x13500303.

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RO - Al 2 O 3- B 2 O 3- SiO 2( R = Ca , Mg ) glasses containing different concentrations of TiO 2 (ranging from 0 to 9 mol.%) were prepared by conventional melting method. When TiO 2 was present in lower concentrations (≤ 6 mol.%), Fourier-transform infrared spectroscopy (FTIR) indicated that titanium ions took part in network forming positions. However, for further increase in the concentration of TiO 2 (> 6 mol.%), FTIR data indicated the formation of TiO 4 tetrahedrons and TiO 6 octahedrons. The glass transition temperatures (Tg) were determined using a differential scanning calorimetry (DSC). The Tg variation with the concentration of TiO 2 showed an increasing trend up to 6 mol.% of TiO 2 and beyond this concentration, Tg was found to decrease. The dielectric constant εr and loss tan δ continued to decrease with the concentration of TiO 2 up to 6 mol.% and beyond that εr and tan δ were found to increase. This behavior was mainly explained in terms of the rigidity of glass network.

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ARDELEAN, I., RALUCA CICEO-LUCACEL i I. BRATU. "IR SPECTRAL INVESTIGATION OF xCuO(100-x)[2B2O3·TeO2] GLASS SYSTEM". Modern Physics Letters B 15, nr 06n07 (20.03.2001): 199–203. http://dx.doi.org/10.1142/s0217984901001513.

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Samples belonging to x CuO (100-x)[2 B 2 O 3· TeO 2] vitreous system with 0≤x≤30 mol% CuO were investigated by FTIR spectroscopy in order to obtain information about the influence of CuO on the local order from 2 B 2 O 3· TeO 2 glass matrix. The interpretation of the obtained vibrational spectra revealed the presence of BO 3 units and boroxol rings in the structure of investigated borate-tellurite glasses. No BO 4 units were detected.

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Gao, Zi Wei, Xue Cheng Zhu, Sheng Jie Yang i Hong Yan Nie. "The FTIR Analysis of Field Aged Composite Insulators". Advanced Materials Research 1008-1009 (sierpień 2014): 620–23. http://dx.doi.org/10.4028/www.scientific.net/amr.1008-1009.620.

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With the increasing of the amount of composite insulators in power network, the transmission accidents caused by the fault of composite insulators are increased and the aging of composite insulators should be paying more attention. In the paper, fourier transform infrared spectroscopy (FTIR) is used to analysis the molecular structure of silicone rubber material of composite insulators. The results indicated that the higher the electric field of the insulator shed, the lower the peak of FTIR spectra. The heavier pollution the sample run, the lower the peak of FTIR spectra. So more attention should be pay to the samples which run in heavier pollution region or the high field part of the insulator.

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Xu, Xing Jun, Yun Long Yue, Hai Tao Zhang i Zhao Du. "Effect of MgO on Structure and Properties of CaO-Al₂O₃-SiO₂ Glass System". Advanced Materials Research 306-307 (sierpień 2011): 531–34. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.531.

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CaO-Al2O3-SiO2system glasses with MgO were prepared by melt quenching. The glass structure was characterized by Infrared spectra (IR) and Differential Thermal Analysis (DTA). Dielectric properties, devitrification and chemical durability have been studied. IR spectra and DTA indicated that glass network structure change by doping MgO. The glass chemical improved and dielectric constant decreased after doping with MgO. The glass shows a severe tendency of phase separation.

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Mohan, Shaweta, D. P. Singh i Simranpreet Kaur. "Structural and optical investigations of CdO-Na2CO3-H3BO3 glasses". Canadian Journal of Physics 93, nr 7 (lipiec 2015): 796–801. http://dx.doi.org/10.1139/cjp-2014-0404.

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Glasses with composition xCdO-(40-x) Na2CO3-60H3BO3; x = 10, 20, 30 and 40 mol% were prepared by conventional melt-quenching technique and checked by XRD technique for their amorphous nature. An increase in density and refractive index of the samples with an increase in content of CdO has been observed and discussed. The optical absorption spectra of the glasses were recorded in the range 200–1100 nm and was used to find optical mobility gap, Urbach energy, and cut-off wavelength for each sample. The decrease in optical mobility gap with increase in CdO points towards the compactness of the structure with the addition of CdO. FTIR spectroscopy reveals the presence of trigonal and tetrahedral borate units, and the results indicate the conversion of BO3 to BO4 units with the increase in CdO content.

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Thonglem, S., Sukum Eitssayeam, Gobwute Rujijanagul, Tawee Tunkasiri, Kamonpan Pengpat i A. Munpakdee. "Fabrication of P₂O₅-CaO-Na₂O Glasses Doped with Zinc Oxide for Artificial Bone Applications". Advanced Materials Research 506 (kwiecień 2012): 509–12. http://dx.doi.org/10.4028/www.scientific.net/amr.506.509.

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The purpose of this work was to study the effect of ZnO on properties of P2O5-CaO-Na2O glass system for bone substituting applications. The glass formula used in this study is 45P2O5- (30-x)CaO - 25Na2O - xZnO where x = 0, 1 , 3, and 5 mol%. The corresponding glasses were prepared by conventional glass melting technique at 1000 °C for 1 h. Thermal parameters of each glass were studied by differential thermal analysis (DTA). These glasses were investigated in terms of infrared spectra and in vitro bioactivity. DTA results gave the glass transition temperatures in a range 227-280°C and crystallization temperatures in the range 521-529°C. Form FTIR results, the infrared spectra of all glass samples showed vibrations of phosphate network and the transmittance intensity of glass systems decreased with increasing ZnO content. All glass samples were exhibited the growth of apatite cells at the surface after immersed in SBF for 7 days. The optimum composition was found for the glass samples containing 5 mol% ZnO which contained the most apatite layer formation.

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Kumi-Barimah, Eric, Yan Chen, Rebekah Tenwick, Mohanad Al-Murish, Geeta Sherma i Animesh Jha. "Effect of Yb3+ on the Structural and Visible to Near-Infrared Wavelength Photoluminescence Properties in Sm3+-Yb3+-Codoped Barium Fluorotellurite Glasses". Materials 15, nr 9 (5.05.2022): 3314. http://dx.doi.org/10.3390/ma15093314.

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We report on the Sm3+ and Sm3+:Yb3+-doped barium fluorotellurite glasses prepared using the conventional melting and quenching method. The spectroscopic characterisations were investigated with Raman and FTIR to evaluate the glasses’ structural and hydroxyl (-OH) content. The Raman analysis revealed a structural modification in the glass network upon adding and increasing the Yb3+ concentration from a TeO3 trigonal pyramid to a TeO4 trigonal bi-pyramid polyhedral. At the same time, the FTIR measurements showed the existence of -OH groups in the glass. Thus, under the current experimental conditions and nominal composition, the -OH group contents are too large to enable an effective removal. The near-infrared region of the absorption spectra is employed to determine the nephelauxetic ratio and bonding parameters. The average nephelauxetic ratio decreases, and the bonding parameter increases with the increasing Yb3+ content in the glasses. A room temperature visible and near-infrared photoluminescence ranging from 500 to 1500 nm in wavelength and decay properties were investigated for glasses doped with Sm3+ and Sm3+-Yb3+ by exciting them with 450 and 980 nm laser sources. Exciting the Sm3+- and Sm3+-Yb3+-doped glasses by 450 nm excitation reveals a new series of photoluminescence emissions at 1200, 1293, and 1418 nm, corresponding to the 6F11/2 state to the 6HJ (J = 7/2, 9/2, 11/2) transitions. Under the 976 nm laser excitation, a broad photoluminescence emission from 980 to 1200 nm was detected. A decay lifetime decreased from ~244 to ~43 μs by increasing the Yb3+ content, ascribing to concentration quenching and the OH content.

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DU, ZHAO, XUEHONG ZHANG, YUNLONG YUE i HAITAO WU. "EFFECT OF MgO ON STRUCTURE AND DIELECTRIC PROPERTIES OF CaO–Al2O3–B2O3–SiO2 GLASSES". Surface Review and Letters 19, nr 06 (27.11.2012): 1250063. http://dx.doi.org/10.1142/s0218625x12500631.

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The effect of MgO on structure and dielectric properties of aluminoborosilicate glasses was investigated. FTIR data indicated that glass network was mainly built by tetrahedral [ SiO4 ], [ BO4 ], [ AlO4 ] and trigonal [ BO3 ]. A small amount of AlO5 or AlO6 units also existed. The glass system was characterized with lower dielectric constant (4.17 ~ 4.6) and dielectric loss (12.3 × 10-4 ~ 14.77 × 10-4) at 1 MHz. With the increase of MgO content, the quantity of AlO5 or AlO6 units decreased. The variation of density showed a decreasing tendency. The dielectric constant and loss were all found to decrease.

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Mošner, Petr, Tomáš Hostinský, Ladislav Koudelka, Marta Razum, Luka Pavić, Lionel Montagne i Bertrand Revel. "Structure-Property Correlation in Sodium Borophosphate Glasses Modified with Niobium Oxide". Coatings 12, nr 11 (26.10.2022): 1626. http://dx.doi.org/10.3390/coatings12111626.

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Bulk glasses of the series (100−x)[0.4Na2O-0.2Nb2O5-0.4P2O5]-xB2O3 with x = 0–48 mol% B2O3 were prepared by slow cooling in air. Their glass transition temperature increases within the range of 0–16 mol% B2O3, but further additions of B2O3 result in its decrease. Their structure was investigated by Raman, 11B, and 31P MAS NMR spectroscopy. The relative number of BO4 units decreases with increasing B2O3 content, while the number of BO3 units increases up to 59 % at x = 48. The upfield shift of a broad resonance peak in the 31P MAS NMR spectra is ascribed to an increasing connectedness of the structural network with increasing B2O3 content. Strong Raman band at 916–929 cm−1 shows on the presence of NbO6 octahedra in the structural network of these glasses. With the B2O3 addition, a decrease in DC conductivity is observed, which is attributed to the decrease in the concentration of Na+ ions.

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Hassaan, M. Y., H. A. Saudi, Hossam M. Gomaa i Ammar S. Morsy. "Optical Properties of Bismuth Borate Glasses Doped with Zinc and Calcium Oxides". Journal of Materials and Applications 9, nr 1 (15.05.2020): 46–54. http://dx.doi.org/10.32732/jma.2020.9.1.46.

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Some bismuth-borate oxide glass' samples were prepared by the fast quenching method, where B2O3 was replaced with equal concentrations of ZnO and CaO. X-ray diffraction (XRD) was used to examine the internal structure and Fourier transform infrared (FTIR) to identify building units and bonds throughout the studied structural matrices. XRD showed that all samples have short range order structural nature, while FTIR demonstrated some of Zn2+ acted as glass network formers and all Bi3+ acted as glass. UV-visible measurements and calculations showed a decreasing in the energy band gap from 3.83 eV to 1.73 eV with decreasing B2O3 content. Also with decreasing B2O3 content, both real refractive index and metallization factor decreased from 3.1 to 1.9 and from 0.56 to 0.71, respectively. For the studied glass' samples, density and molar volume showed inverted behaviors, where the density decreased while the molar volume increases with decreasing B2O3.

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ARDELEAN, I., N. MUREŞAN i P. PĂŞCUŢĂ. "IR AND RAMAN SPECTROSCOPIC INVESTIGATIONS OF Cr2O3-TeO2-B2O3-SrO GLASSES". Modern Physics Letters B 18, nr 09 (10.04.2004): 367–73. http://dx.doi.org/10.1142/s0217984904006974.

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The Cr 2 O 3 content influence on the structure of 70 TeO 2·25 B 2 O 3·5 SrO glasses, was investigated by infrared and Raman spectroscopies. The results show that BO 3 and BO 4 are among the main structural units in the investigated glasses, together with TeO 3 and TeO 4 units. The presence of chromium ions located in the glass network is well evidenced in the IR and Raman spectra.

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Ejigu A, Afrash, K. P. Ramesh i Gajanan Honnavar. "Vibrational, Thermal, and Physical Characterizations of Some Zinc Niobo Tellurite Glasses Doped with Rare Earth (Eu, Dy)-=SUP=-*-=/SUP=-". Оптика и спектроскопия 129, nr 4 (2021): 527. http://dx.doi.org/10.21883/os.2021.04.50785.1012-20.

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In this communication, we report physical and thermal properties along with Raman spectroscopic investigations on Zinc Niobo Tellurite glass systems doped with Eu2O3 and Dy2O3 at the expense of TeO2. The glasses have been synthesized by the melt quenching technique. Physical parameters like density, molar volume, packing density were estimated. The density of the un-doped glasses increases with increasing mol% of the modifier (ZnO) whereas the glass transition temperature (Tg) decreases. We have observed an increase in the density of the base glass systems which are doped with rare earth (RE) dopants. The packing density of the un-doped glasses remains almost constant with increasing modifier content suggesting that there is not much change in the local environment. Raman spectra were recorded at room temperature and assigned to TeO4 and TeO3 structural units in these glasses. The peak shift, full width at half maximum (FWHM) of the de-convoluted Raman peaks were analyzed to get information about the local environment. It is observed that these compositions of tellurite glasses are good host materials for rare earth ions as they offer voids in the network. Further, it was observed that the rare earth ion doping has not affected the local environment of the glasses; Dy3+ ions have a slightly higher tendency to polarize Te-O bonds than the Eu3+ ions. Keywords: Niobium-based tellurite glasses, XRD, DSC, FTIR.

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Zaiter, Rayan, Mohammad Kassem, Daniele Fontanari, Arnaud Cuisset, Chris J. Benmore i Eugene Bychkov. "Ionic transport and atomic structure of AgI-HgS-GeS2 glasses". Pure and Applied Chemistry 91, nr 11 (26.11.2019): 1807–20. http://dx.doi.org/10.1515/pac-2019-0103.

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Abstract Quasi-ternary (AgI)x(HgS)0.5−x/2(GeS2)0.5−x/2 glasses, 10−4≤x≤0.6 were studied over a wide composition range covering nearly 4 orders of magnitude in the mobile cation content. The glasses show a remarkable increase of the ionic conductivity by 12 orders of magnitude and exhibit two drastically different ion transport regimes: (i) a power-law critical percolation at x≲0.04, and (ii) a modifier-controlled conductivity, exponentially dependent on x≳0.1. Using Raman spectroscopy and high-energy X-ray diffraction supported by DFT modelling of the Raman spectra we show that the glass network is essentially formed by corner-sharing CS-GeS4/2 tetrahedra. Mercury sulfide in glasses is dimorphic. The majority of Hg species (70% at x<0.2) exist as two-fold coordinated (HgS2/2)n chains. Silver species have mixed (2I+2S) tetrahedral environment forming either edge–sharing ES-Ag2I2S4/2 dimers or corner-sharing (CS-AgI2/2S2/2)n chains. The relationship between the ionic transport and atomic structure of the glasses is discussed.

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Chungong, Louis Forto, Mark A. Isaacs, Alexander P. Morrell, Laura A. Swansbury, Alex C. Hannon, Adam F. Lee, Gavin Mountjoy i Richard A. Martin. "Insight into the atomic scale structure of CaF2-CaO-SiO2 glasses using a combination of neutron diffraction, 29Si solid state NMR, high energy X-ray diffraction, FTIR, and XPS". Biomedical Glasses 5, nr 1 (1.01.2019): 112–23. http://dx.doi.org/10.1515/bglass-2019-0010.

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Abstract Bioactive glasses are important for biomedical and dental applications. The controlled release of key ions, which elicit favourable biological responses, is known to be the first key step in the bioactivity of these materials. Properties such as bioactivity and solubility can be tailored for specific applications. The addition of fluoride ions is particularly interesting for dental applications as it promotes the formation of fluoro-apatite. To date there have been mixed reports in the literature on how fluorine is structurally incorporated into bioactive glasses. To optimize the design and subsequent bioactivity of these glasses, it is important to understand the connections between the glass composition, structure and relevant macroscopic properties such as apatite formation and glass degradation in aqueous media. Using neutron diffraction, high energy X-ray diffraction, 29Si NMR, FTIR and XPS we have investigated the atomic scale structure of mixed calcium oxide / calcium fluoride silicate based bioactive glasses. No evidence of direct Si-F bonding was observed, instead fluorine was found to bond directly to calcium resulting in mixed oxygen/fluoride polyhedra. It was therefore concluded that the addition of fluorine does not depolymerise the silicate network and that the widely used network connectivity models are valid in these oxyfluoride systems.

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Arafat, Abul, Sabrin A. Samad, Jeremy J. Titman, Andrew L. Lewis, Emma R. Barney i Ifty Ahmed. "Yttrium doped phosphate-based glasses: structural and degradation analyses". Biomedical Glasses 6, nr 1 (18.11.2020): 34–49. http://dx.doi.org/10.1515/bglass-2020-0004.

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AbstractThis study investigates the role of yttrium in phosphate-based glasses in the system 45(P2O5)–25(CaO)– (30-x)(Na2O)–x(Y2O3) (0≤x≤5) prepared via melt quenching and focuses on their structural characterisation and degradation properties. The structural analyses were performed using a combination of solid-state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). 31P NMR analysis showed that depolymerisation of the phosphate network occurred which increased with Y2O3 content as metaphosphate units (Q2) decreased with subsequent increase in pyrophosphate species (Q1). The NMR results correlated well with structural changes observed via FTIR and XPS analyses. XRD analysis of crystallised glass samples revealed the presence of calcium pyrophosphate (Ca2P2O7) and sodium metaphosphate (NaPO3) phases for all the glass formulations explored. Yttrium-containing phases were found for the formulations containing 3 and 5 mol% Y2O3. Degradation analyses performed in Phosphate buffer saline (PBS) and Milli-Q water revealed significantly reduced rates with addition of Y2O3 content. This decrease was attributed to the formation of Y-O-P bonds where the octahedral structure of yttrium (YO6) cross-linked phosphate chains, subsequently leading to an increase in chemical durability of the glasses. The ion release studies also showed good correlation with the degradation profiles.

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Saito, Noritaka, Daiji Nakata, Sohei Sukenaga i Kunihiko Nakashima. "Viscosity Measurement of Molten RE-Mg-Si-O-N (RE=Y, Gd, Nd and La) Glasses". Key Engineering Materials 403 (grudzień 2008): 69–72. http://dx.doi.org/10.4028/www.scientific.net/kem.403.69.

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Viscosities of molten RE-Mg-Si-O-N (RE=Y, Gd, Nd and La) glasses have been measured using rotating bob viscometer with a gas tight furnace at elevated temperature (~1873 K). Moreover, structural characterizations of these quenched vitreous samples have been investigated using solid state 29Si MAS-NMR, which would resolve the relationship between the viscosity of high temperature melts and network structure of RE-Mg-Si-O-N systems. The viscosities of molten RE-Mg-Si-O-N glasses exponentially increased with nitrogen content. 29Si MAS-NMR spectra of RE-Mg-Si-O-N (RE=Y and La) glasses revealed that content of silicon-oxynitride species, like SiO3N, increased with nitrogen content, which indicates that nitrogen clearly modifies the glass network structure. Depending on cationic radius of rare-earth elements, Y was found to be more effective in silicon-oxynitride species formation than La, which are consistent with the results of viscosity measurement of molten RE-Mg-Si-O-N glasses at elevated temperature (~1873 K).

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SIMON, V., L. BARZǍ, S. SIMON, S. G. CHIUZBǍIAN i M. NEUMANN. "ATOMIC ENVIRONMENT CHANGES INDUCED BY IRON ADDITION TO GALLIUM BISMUTHATE GLASSES". International Journal of Modern Physics B 18, nr 01 (10.01.2004): 45–52. http://dx.doi.org/10.1142/s0217979204023660.

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Atomic environment of x Fe 2 O 3·(80-x) Bi 2 O 3·20 Ga 2 O 3 heavy glasses (0≤x≤20 mol %) was investigated with respect to electronic structure of the samples. Data obtained from Bi 4f, Ga 2p, Fe 2p, and O 1s core-level photoelectron spectra indicate changes in the local order on the account of partial substitution of bismuth by iron. The bismuth cations behave essentially as network formers while the iron and gallium ones acts as network modifiers. The number of nonbridging oxygens depends on Fe 2 O 3 content.

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Elbatal, F. H. A., M. A. Marzouk, Y. M. Hamdy i H. A. ElBatal. "Optical and FT Infrared Absorption Spectra of 3d Transition Metal Ions Doped in NaF-CaF2-B2O3 Glass and Effects of Gamma Irradiation". Journal of Solid State Physics 2014 (2.12.2014): 1–8. http://dx.doi.org/10.1155/2014/389543.

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Combined optical and FTIR spectroscopy has been employed to investigate the undoped NaF-CaF2-B2O3 glass together with samples containing 0.2% dopant of 3d TM ions before and after gamma irradiation. The optical spectrum of the undoped glass reveals strong UV absorption with two peaks which are related to unavoidable trace iron impurity within the raw materials. Upon gamma irradiation, an induced visible broad band centered at 500 nm is resolved and is related to B-O hole center or nonbridging oxygen hole center. TMs-doped samples exhibit characteristic absorption due to each respective TM ion but with faint colors. Gamma irradiation of TMs-doped samples reveals the same induced visible band at 500–510 nm in most samples except CuO and Cr2O3-doped glasses. Infrared absorption spectra reveal characteristic vibrational bands due to triangular and tetrahedral borate groups. The introduction of NaF and CaF2 modifies the borate network forming BO3F tetrahedra. The introduction of 3d TMs as dopants did not make any obvious changes in the FTIR spectra due to their low content (0.2%). Gamma irradiation causes only minor variations in the intensities of the characteristic IR borate bands while the bands at about 1640 cm−1 and 3450 cm−1 reveal distinct growth in most samples.

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Lesniak, Magdalena, Jacek Zmojda, Marcin Kochanowicz, Piotr Miluski, Agata Baranowska, Gabriela Mach, Marta Kuwik, Joanna Pisarska, Wojciech A. Pisarski i Dominik Dorosz. "Spectroscopic Properties of Erbium-Doped Oxyfluoride Phospho-Tellurite Glass and Transparent Glass-Ceramic Containing BaF2 Nanocrystals". Materials 12, nr 20 (20.10.2019): 3429. http://dx.doi.org/10.3390/ma12203429.

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The ErF3-doped oxyfluoride phospho-tellurite glasses in the (40-x) TeO2-10P2O5-45 (BaF2-ZnF2) -5Na2O-xErF3 system (where x = 0.25, 0.50, 0.75, 1.00, and 1.25 mol%) have been prepared by the conventional melt-quenching method. The effect of erbium trifluoride addition on thermal, structure, and spectroscopic properties of oxyfluoride phospho-tellurite precursor glass was studied by differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR), and Raman spectroscopy as well as emission measurements, respectively. The DSC curves were used to investigate characteristic temperatures and thermal stability of the precursor glass doped with varying content of ErF3. FTIR and Raman spectra were introduced to characterize the evolution of structure and phonon energy of the glasses. It was found that the addition of ErF3 up to 1.25 mol% into the chemical composition of phospho-tellurite precursor glass enhanced 2.7 µm emission and upconversion. By controlled heat-treatment process of the host glass doped with the highest content of erbium trifluoride (1.25 mol%), transparent erbium-doped phospho-tellurite glass-ceramic (GC) was obtained. X-ray diffraction analysis confirmed the presence of BaF2 nanocrystals with the average 16 nm diameter in a glass matrix. Moreover, MIR, NIR, and UC emissions of the glass-ceramic were discussed in detail and compared to the spectroscopic properties of the glass doped with 1.25 mol% of ErF3 (the base glass).

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Caccamo, Maria Teresa, Giuseppe Mavilia, Letterio Mavilia, Domenico Lombardo i Salvatore Magazù. "Self-Assembly Processes in Hydrated Montmorillonite by FTIR Investigations". Materials 13, nr 5 (2.03.2020): 1100. http://dx.doi.org/10.3390/ma13051100.

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Experimental findings obtained by FTIR and Raman spectroscopies on montmorillonite-water mixtures at three concentration values are presented. To get some insight into the hydrogen bond network of water within the montmorillonite network, FTIR and Raman spectra have been collected as a function of time and then analyzed following two complementary approaches: An analysis of the intramolecular OH stretching mode in the spectral range of 2700–3900 cm−1 in terms of two Gaussian components, and an analysis of the same OH stretching mode by wavelet cross-correlation. The FTIR and Raman investigations have been carried as a function of time for a montmorillonite-water weight composition (wt%) of 20–80%, 25–75%, and 35–65%, until the dehydrated state where the samples appear as a homogeneous rigid layer of clay. In particular, for both the FTIR and Raman spectra, the decomposition of the OH stretching band into a “closed” and an “open” contribution and the spectral wavelet analysis allow us to extract quantitative information on the time behavior of the system water content. It emerges that, the total water contribution inside the montmorillonite structure decreases as a function of time. However, the relative weight of the ordered water contribution diminishes more rapidly while the relative weight of the disordered water contribution increases, indicating that a residual water content, characterized by a highly structural disorder, rests entrapped in the montmorillonite layer structure for a longer time. From the present study, it can be inferred that the montmorillonite dehydration process promotes the layer self-assembly.

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