摘要:

Sol-gel derived PbO-TiO2waveguides were prepared on pyrex substrates using the dip coating technique. Heat treatments conducted at 200[ddot]C, 300[ddot]C and 400[ddot]C for one hour led to the densification of the layers and the increase of the refractive index values. The effect of water concentration in the precursor sol on the optical qualities of the waveguides is reported. Monolayer waveguides prepared with high water concentration provided the best coefficients of attenuation values (< 1 dB/cm). Preliminary study of Waveguide Raman Spectroscopy is presented.

ISSN:1042-0150    

DOI:10.1080/10420159508222713

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Ultrasonic attenuation measurements are carried out for a quartz specimen irradiated with 4.7 × 1019n/cm2and annealed at 700[ddot]C during 1 hour. This dose is interesting because it is situated in the ‘threshold region'. The measurements are carried out as a function of temperature (0.3–20 K) for different frequencies (80–300 MHz). The data show a behaviour that is qualitatively similar to previous observations for a much lower dose, and indicate a tendency to return to the crystalline state.

ISSN:1042-0150    

DOI:10.1080/10420159508222714

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The K4.2Ti1.2(PO4)3glass was used to study the interaction between dipoles and ions by dielectric and Raman spectroscopy. The activation energies for the K+migration and dipole orientation were evaluated to be 0.61 ± .01 eV and 1.11 ± .02 eV, respectively. Two coordinations of Ti were identified by the Raman scattering experiment. Decrease of the Raman scattering intensity was observed under the static electric field.

ISSN:1042-0150    

DOI:10.1080/10420159508222715

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Laser irradiation induced structural relaxation in the densified SiO2glass and SiO2thin film has been probed by collinear photothermal deflection spectroscopy (PDS). Decreasing of optical absorption with the irradiation of Ar+laser beam was observed in the densified SiO2glass and SiO2thin film. The structural relaxation is associated with the reactivation and recombination of localized defects which can be well described by the proposed relaxation function of (t) = (1 +at)−b. Distribution of relaxation times of the densified glass is broader than that of thin film.

ISSN:1042-0150    

DOI:10.1080/10420159508222716

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Thin films from the systems Se-Ag-I and Te-Ag-I are investigated. The optical transmission spectra are measured and the optical band gap is estimated on their basis. The temperature relationship of the electrical conductivity is measured and the activation energy is determined. Some relationships between these parameters and the composition of the glasses are discussed.

ISSN:1042-0150    

DOI:10.1080/10420159508222717

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Thermally stimulated depolarization currents and some spectrophotometric characteristics were measured for soda lime silicate glass in as received state and after exchange with ionic silver. Both, the effectiveness of the exchange and the form of silver within the glass framework, were modified by thermal treatment of the exchanged specimens.

ISSN:1042-0150    

DOI:10.1080/10420159508222718

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A thermally stimulated depolarization current was measured in pure silica glasses and crystalline quartz, after a linear temperature increase under applied electric field, up to 520 K. The depolarization peak at 480 K disappeared after UV illumination at room temperature. A negative depolarization current was observed in silica glasses after polarization by an electric field under UV illumination at room temperature. There exist two different types of dipoles which are electron-hole pairs, in which electron and hole are trapped on two different defects respectively.

ISSN:1042-0150    

DOI:10.1080/10420159508222719

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Raman investigations have been performed on K0.984Li0.016TaO3and KTa0.976Nb0.024O3single crystals, in order to follow the peculiarities of non-ferroelectric phonons, which may be indicative of a different evolution of microscopic order during the polar transition. Specific features in the Nb case confirm a ferroelectric behaviour, whereas in the Li-doped sample the results are in agreement with a dipole glass transition.

ISSN:1042-0150    

DOI:10.1080/10420159508222720

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper deals with the properties of dislocations in some ceramic materials. The implication of the intimate structure of dislocations revealed at the TEM level, on the macroscopic properties is discussed. Not only consequences on mechanical properties are taken into account but also consequences on physical properties. Examples are given for structural ceramics (ZrO2), as well as for superconducting ceramics (YBa2Cu3O7-∞). In this latter class of materials it is shown that dislocations can be used to locally change the thermodynamic range of nucleation of non stoichiometric phases. Pinning of vortices by dislocations is also discussed.

ISSN:1042-0150    

DOI:10.1080/10420159508222721

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

CaF2single crystals have been deformed in compression along various axis in order to determine their slip systems. Strong plastic anisotropy was found below 600[ddot]C. The slip planes are {100}, {111} and {110}, the CRSS increasing from the first to the last.

ISSN:1042-0150    

DOI:10.1080/10420159508222722

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor