Scaling Behavior between Heat Capacity and Thermal Expansion in Solids

We experimentally analyze the heat capacity and thermal expansion of reference solids in a wide temperature range from several Kelvin to melting temperature,and establish a universal double-linear relation between the experimental heat capacity C_(p) and thermal expansion β,which is different from the previous models.The universal behavior between heat capacity and thermal expansion is important to predict the thermodynamic parameters at constant pressure,and is helpful for understanding the nature of thermal properties in solids.

Optical,thermal and luminescence properties of La2O3-Ga2O3-ZrO2 glasses co-doped with Tm3+/Yb3+prepared by containerless technique

Bulk LaO-GaO-ZrO(LGZ)glass and Tm/Ybco-doped LGZ glasses were synthesized successfully using containerless technique.Raman spectra result reveals that the matrix sample possesses the low maximum phonon energy of~642 cm.The glasses show good compatibility between large Abbe numbers(>31)and high refractive indices(n>1.93).Moreover,transmittance measurements reflect that the glasses have high infrared transmittance of-81.9%,small OHabsorption coefficient and long mid-infrared cut-off wavelengths(-7.5μm).The surface morphology of host glass was characterized by scanning electron microscopy(SEM)micrograph and energy dispersive spectroscopy(EDS)tests reflect that the doped compositions are distributed into the matrix glass homogeneously.The results of thermal analysis show that the glasses have good thermal properties(T>769℃).Excited by 980 am laser,an intense 1810 am fluorescence is obtained originating from the transition:~3 E→~3 Hof Tmion,accompanied by upconversion emission.It can be observed that 1810 nm fluorescence has the highest intensity at 1 mol%YbOand owns broad full width at half-maximum(>245 nm),the luminescence intensity of~3 F→~3 Htransition increases with rising temperature from 300 to 550 K.Furthermore,the value of energy transfer efficiency shows that Ybcan transfer energy to Tmeffectively.By fitting the attenuation curves,the lifetimes of 1810 and 474 nm emission can be acquired.