Peterson, Irene M.?Tseng-Ying Tien
The thermal expansion coefficients and glass transition temperatures of Y-Mg-Si-Al-O-N glasses were measured using dilatometry. The thermal expansion coefficients of these glasses could be calculated on the basis of composition, using experimetaly determined thermal expansion prefactors.
Zhang, Lipeng?Wang, Paul W.
The effect of chlorine on the structure of AlF//3/YF//3-based fluoride glasses was studied by XPS. The changes in the bonding state of cations with increase of chlorine content were all investigated by measuring the composition- dependent changes in the relative concentration and binding energy of related cations. (more…)
Todoroki, Shin-ichi?Sakaguchi, Shigeki
The Rayleigh scattering of silicate glasses (M//2O-RO-SiO//2, M: Na and K, R: Mg, Ca, and Zn) was measured. Soda magnesium silicate (NMS) glasses exhibited the smallest scattering intensity. It is comparable with that of soda aluminosilicate (NAS) glass, one of the candidates for use in fabricating ultralow- loss fibers. (more…)
In order to study Ne diffusion into glasses, we measured noble gas concentrations in obsidian samples which were degassed in a vacuum at 800°C and subsequently heated in air at various temperatures and heating times. Neon was concentrated in samples which were kept at room temperature, indicating that Ne is easily diffused into obsidians from the atmosphere even at room temperature. We also measured noble gas concentrations in five size-separated fractions of the obsidian (ME1) (>250, 149-250, 74-149, 46-74 and <46 ?m fractions) and in three size-separated fractions of tektite (TE6) (>250 and 149-250 ?m fractions and powdered fraction) to examine the degassing effect on noble gases by crushing. (more…)
Structural and quantitative effects of different electron scavenger concentrations on the free radical formation in the nucleotide thymidine-5′-monophosphate (TMP) and in deoxyribonucleic acid (DNA) after X-irradiation in frozen aqueous solution and glasses (BeF2/H2O for TMP and LiCl/H2O for DNA) at 77 K are investigated. At the highest concentration used (100 mmol dmm3) about 80% (TMP) and 70% (DNA) of the radicals are scavenged compared with the control in both matrices. In TMP, allyl radicals form the major population of radicals left unscavenged at 77 K. These are shown to transform into a quintet pattern upon annealing (S 220 K). Analysis of various substrates for quintet formation shows that a sugar-group and a C4-carbonyl group are necessary structural prerequisites. (more…)
The mobility of an organic volatile probe (1-n-propanol), incorporated in two types of amorphous carbohydrate glasses, was evaluated by measuring probe retention as a function of time. Retention was found to depend on temperature, moisture content and the degree of matrix collapse. In sucrose glasses, crystallization and probe release occur simultaneously and both crystallization and release depend on the temperature above Tg, as predicted by the William-Landel-Ferry (WLF) equation. (more…)
Nineteen current makes of sports glasses and six older types of sunglasses were tested for spectral UV transmission. Transmissions in the UVB range (280–320 nm) were less than 10^-4; all glasses therefore offered 100% protection against keratitis. (more…)
We present the experimental results on the effects of hydrogen doping on the superconducting and paramagnetic properties of zirconium-rich (x > 0.66) Zrx3d1-x metallic glasses. Zr0.70Cu0.30, Zr0.67Ni0.33 and Zr0.67Co0.33 are superconductors with a superconducting transition temperature in the vicinity of 2 K, while Zr0.68Fe0.32 is a paramagnet down to very low temperatures because of pronounced spin-fluctuations. (more…)
High-magnetostriction Fe-rich metallic glasses in the form of ribbons presenta magnetoelastic resonance characterized by the frequency of the longitudinal vibrational mode ofthe sample, /spl omega//sub r/, which is a function of the applied static field, H. This value of/spl omega//sub r/ can be used to recognize different objects or the position of a single object ina field gradient, that is as a carrier of information. (more…)
We investigate dynamical systems of gauge symmetric Ising spin glasses usingthe method of the gauge transformation. Several exact relations are derived among dynamicalquantities such as the equilibrium auto-correlation function and the non-equilibrium remanentmagnetization. The same result as in the static case is obtained in terms of the equivalence of theferromagnetic and the spin glass order (more…)
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