Showing papers by "Wuhan University of Technology published in 1989"
TL;DR: In this article, EXAFS and Mossbauer spectroscopies have been used to study the structure of iron in Fe 2 O 3 P 2 O 5 glasses.
Abstract: In the present paper, EXAFS and Mossbauer spectroscopies have been used to study the structure of iron in Fe 2 O 3 P 2 O 5 glasses, Na 2 OFe 2 O 3 P 2 O 5 glasses and the samples which are obtained from heat-treated iron metaphosphate glass. The results indicate that ferric and ferrous ions are present in the phosphate glasses, and Fe 3+ ions are coordinated with both four and six oxygens, but Fe 2+ ions are only in six-coordination. The proportion of each kind of iron ion to the total iron ions changes with a composition of the glasses and heat treatment conditions of the samples. The coordination number of Fe 3+ ions in an iron phosphate glass is lower than in the iron phosphate crystal with the same composition.
57 citations
TL;DR: In this paper, the effects of V2O5 on phase separation and leaching of sodium borosilicate glasses have been studied by the observation of microphases, the measurement of immiscibility temperature and the determination of leaching rate.
Abstract: The effects of V2O5 on the phase separation and leaching of sodium borosilicate glasses have been studied by the observation of microphases, the measurement of immiscibility temperature and the determination of leaching rate. We conclude that V2O5 can largely enhance phase separation and so increase the size of the phase-separated interconnecting “filaments”. As a result of the phase separation, the silica content in the alkali-borate-rich phase decrease with V2O5 additions. Therefore, the amount of SiO2 gel deposited in the cavity of the silica-rich phase skeleton in the leaching process decreases as compared with that without V2O5 additions. Also, the diffusion rate of the soluble phases increases heavily because of the decrease of the diffusion barrier. In addition, the solubility of the sodium borate phases in increased by the addition of V2O5. All the above effects explain why the addition of a small amount of V2O5 is very effective in increasing the leaching rate.
9 citations
TL;DR: In this article, the infrared cut-off wavelengths of CdF 2 PbCl 2 ǫ-KI are 9.5 μm and 18 μm, respectively.
Abstract: Some new mixed halide glasses, CdF 2 PbCl 2 , CdF 2 PbCl 2 , CdF 2 PbCl 2 KBr, CdBr 2 PbCl 2 KI and CdI 2 PbCl 2 KBr systems, were synthesized. Samples 4 mm thickness could be synthesized in the CdF 2 PbCl 2 and CdF 2 PbCl 2 KBr systems. The infrared cut-off wavelengths of CdF 2 PbCl 2 KI are 9.5 μm and 18 μm, respectively. The structure of CdF 2 PbCl 2 glass was studied by X-ray photoelectron spectroscopy, X-ray diffraction, and infrared and Raman spectral analysis. The Cd 2+ ion in the glasses is coordinated by F and Cl ions, the distance of two Cd 2+ ions being about 4.0 A and the FCdF angle about 60°. Compared with the [CdF 8 ] unit in the crystalline state the [CdX n ] units in glass have large deformations.
9 citations
TL;DR: The vitreous region of the oxyfluoride system based on germanium dioxide, lead fluoride and zinc fluoride is obtained by using platinum crucibles as mentioned in this paper, and the physical properties such as the transition temperature, crystallization temperature, refractive index, density, thermal expansion coefficient and elastic modulus are measured.
Abstract: The vitreous region of the oxyfluoride system based on germanium dioxide, lead fluoride and zinc fluoride is obtained by using platinum crucibles. The physical properties such as the transition temperature, crystallization temperature, refractive index, density, thermal expansion coefficient and elastic modulus are measured. A description to the change rules of the physical properties of this system is given in detail. The glasses have a good transparency in the mid-infrared region. Their chemical durability is much better than that of fluoride glasses.
9 citations
TL;DR: In this paper, the microstructures of belite examined by high-resolution electron microscopy (HREM) show the (1 0 0) and (0 0 1) twin lamellae which are introduced by shear stresses during the transformation ofα′−C2S toβ-c2S.
Abstract: The microstructures of belite examined by high-resolution electron microscopy (HREM) show the (1 0 0) and (0 0 1) twin lamellae which are introduced by shear stresses during the transformation ofα′−C2S toβ-C2S.γ-C2S formed in the larnite was identified and the orientation relationship between them was also determined by a composite electron diffraction pattern (EDP), which is different from that suggested earlier by Groves. The EDP and the HREM image showed the existence of the unstable phaseα′L−C2S.
8 citations
TL;DR: In this article, the spatial distribution of crystallites in polar Ba 2 TiSi 2 O 8 glass-ceramics was determined by means of X-ray rocking curves, and an equation for the pyroelectric constant P 3 was derived.
Abstract: The spatial distribution of crystallites in polar Ba 2 TiSi 2 O 8 glass-ceramics was determined by means of X-ray rocking curves. The relationship between the spatial distribution and the pyroelectric constant is discussed. Finally, an equation for the pyroelectric constant P 3 is derived.
8 citations
TL;DR: In this paper, a double melt-quench method was used to produce nitrogen-doped phosphate glasses, which were then used to measure the thermal expansion coefficient and the microhardness of the glass.
Abstract: Nitrogen-doped phosphate glasses were prepared by a double melt-quench method Property measurements show that the addition of nitrogen results in a decrease of the thermal expansion coefficient, but the glass transition temperature, the microhardness and the chemical durability increase by varying degrees In particular the solubility in water decreases sharply with nitrogen content Studies of X-ray photoelectron spectra and Raman spectra show that the structural state of nitrogen in the phosphate glasses is similar to that in crystalline AlN, Si 3 N 4 , and BN and that the majority of nitrogen atoms are coordinated by three phosphorus atoms This results in a more highly cross-linked glass netword because of the stronger bond between P and N X-ray fluorescence analysis indicates that the aluminum in the nitrogen-doped phosphate glass is in mixed four- and six-fold coordination and that the number of six-coordinated Al atoms is slightly larger than that of four-coordinated Al
7 citations
TL;DR: In this article, a biocompatible glass-ceramics which contains muscovite and some kind of fluoroapatite was obtained by heat treatment of a base glass in the system with added CaO and P2O5.
Abstract: A biocompatible glass-ceramics which contains muscovite and some kind of fluoroapatite was obtained by heat treatment of a base glass in the system K2OMgOAl2O3B2O3SiO2F− with added CaO and P2O5 . The material is easily machinable and has some bioactivity. The structure and the phase separation were investigated by infrared spectroscopy, Raman spectroscopy and transmission electron microscopy. The results show that the glass separates into two phases. With added CaO and P2O5, it will separate into three phases. Some properties, such as mechanical strength, were also tested. The biocompatibility and bioactivity of the material were tested by soakingsamples in a simulating liquid (pH 7.4) and by animal experiments.
7 citations
TL;DR: In this article, the ionic conduction in NBAL glasses has been studied based on their Raman spectroscopy, and the effect of composition and structure of the glasses on their ionic conductivity is discussed.
Abstract: New glasses have been prepared in the K2NbOFAlF3(NBAL) system, with the IR spectrum, UV spectrum and the thermal properties measured. The ionic conduction in NBAL glasses has been studied. Based on their Raman spectroscopy, the structure of the glasses is briefly studied. The effect of composition and structure of the glasses on their ionic conductivity is discussed. When the AlF3 content ranges from 21 to 29 mol%, Al3+ and Nb5+ ions are octahedrally coordinated, and the ionic conductivity increases with the AlF3 content. When the AlF3 content reaches 29 mol%, part of the Al3+ ions are tetrahedrally coordinated and the ionic conductivity decreases. The effect is attributed to the formation of AlF−4 which block the moble ion channels. The ionic conductivity of glasses in this system is 1.045 × 10 −2 Ω −1 · cm −1 at 194°C.
6 citations
TL;DR: In this article, the synthesis, thermal behavior, crystallographic and X-ray powder diffraction data, and infrared spectral data for Ca 8 ZnSi 4 O 16 Cl 2 have been determined.
Abstract: The synthesis, thermal behavior, crystallographic and X-ray powder diffraction data, and infrared spectral data for Ca 8 ZnSi 4 O 16 Cl 2 have been determined. This compound is cubic with isolated silicate tetrahedra.
5 citations
TL;DR: In terms of percolation, the critical amount of dopant x c for forming the fully stabilized cubic ZrO 2 phase and the changes in the volume fraction v cp of the stabilized cubic phase with the amount of dopamine x in an MO (or M 2 O 3 )-doped system have been established in this article.
Abstract: In terms of percolation, the critical amount of dopant x c for forming the fully stabilized cubic ZrO 2 phase and the changes in the volume fraction v cp of the stabilized cubic ZrO 2 phase with the amount of dopant x in an MO (or M 2 O 3 )-doped ZrO 2 system have been established, which are consistent with the phase diagrams and the limited data presently available. The effect of the geometrical parameters of ZrO 2 grains on the two values is theoretically predicted.
TL;DR: In this paper, the three factors, chemical composition, photosensitive agents and heat treatment, which affect the photochromic properties of copper-cadmium-halide glasses have been studied.
Abstract: Silver-free photochromic glasses have been prepared using a conventional ceramic. The transmittance of visible light through the glass decreases by 42% and turns deep-green after radiation for 2 min. The three factors, chemical composition, photosensitive agents and heat treatment, which affect the photochromic properties of copper-cadmium-halide photochromic glasses have been studied. The values f ψ between 0.0 and 0.3, the Cu content being less than 0.3 mol% and the Cd/Cu ratio being greater than 3, are suitable for using the R2OAl2O2SiO2 system to prepare silver-free photochromic glass. It is necessary to melt the glasses under a suitable reducing atmosphere and it is best to treat the glass in two stages.
06 Mar 1989
TL;DR: In this paper, a wide-bandgap material with refractive index ~1.5 and good durability was produced by dc magnetron sputtering in Ar + 0 2 + CF 4 at a rate of 1.2 nms -1.
Abstract: Indium-tin-oxyfluoride films were made by dc magnetron sputtering in Ar + 0 2 + CF 4 at a rate of 1.2 nms -1 . A wide-bandgap material, with refractive index ~1.5 and good durability, was produced. It is very well suited for antireflecting indium-tin-oxide coatings. Vanadium-oxyfluoride films were made by rf magnetron sputtering in Ar + 0 2 + CF 4 . Thermo-chromism was studied by electrical and spectral optical measurements. Fluorination was found to yield a significant decrease of the luminous absorptance.
15 May 1989
TL;DR: In this article, the theoretical basis for obtaining mathematical models of the mill torsional-vibration system is discussed, and the dynamic parameters of the practice tube-mill system in cement plants are calculated by using state-space representation and complex modal analysis techniques.
Abstract: It is noted that torsional vibration considerations of the tube mill are very important for the normal operation and design of tube-mill drive systems. The theoretical basis for obtaining mathematical models of the mill torsional-vibration system is discussed. The dynamic parameters of the practice tube-mill system in cement plants are calculated by using state-space representation and complex modal analysis techniques. Also examined is the damping of tube-mill torsional vibration, including such techniques as electromagnetic damping, oil damping, and grinding medium damping. It is shown that these dampings have a powerful effect on the dynamic response of the mill drive system. Experimental research performed on tube-mill systems in cement plants is also reported. The test data and calculated results are shown to agree very well. >
TL;DR: In this article, the lattice instability of YBa2Cu3O7−y superconducting ceramic between 100 and 300 K has been studied by means of ultrasonic measurements, TEM study, X-ray diffraction experiments, thermal analysis and specific heat measurements for samples from different laboratories.
Abstract: The lattice instability of YBa2Cu3O7−y superconducting ceramic between 100 and 300 K has been studied by means of ultrasonic measurements, TEM study, X-ray diffraction experiments, thermal analysis and specific heat measurements for samples from different laboratories. It was shown that there are anomalous changes in lattice constants near 250 K, 170 K and 130 K, together with specific heat anomalies near this temperature region, which is consistent with the longitudinal and transverse ultrasonic results. Such anomalies are caused by an intrinsic lattice instability related to the ordering readjustments of the oxygen vacancies, which was confirmed by the observed tendency of reversible orthohombic to tetragonal phase transition near 170 K.
01 Jan 1989
Abstract: Unsymmetrical angle-ply laminating plates of anisotropic composites are representative in dynamics of plates. After making an analysis of the complete solution analysis process (including calculating examples) of nonlinear flexural forced vibration of plates under the harmonic force, the authors obtain the amplitude—frequency relationship of anisotropic unsymmetrical angle-ply laminating plates under loads of different magnitude, and the effect of the change of the plying layers of laminating plates upon the amplitude—frequency relationship of nonlinear flexural forced vibration. The solution analysis result thus obtained is reliable and the conclusion drawn from the result is representative. What has been done so far is undoubtedly a meaningful attempt in the matter of nonlinear dynamics of composite anisotropic laminating plates and will be of great help in the further research of other nonlinear dynamics of anisotropic laminating plates.