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A series of Silver Nanoparticles embedded in the system of zinc-tellurite glass co-doped Neodymium/Erbium ions with the composition of (69.5-2.5x)TeO2–30ZnCl2–xNd2O3–xEr2O3–(0.5+0.5x)AgCl concentration from 0.0 to 3.0 mol% (x=0, 1, 2 and 3) have successfully been synthesized by melt-quenching techniques. The amorphous nature of the glass was confirmed from x-ray diffraction technique. The decrease of refractive index from 2.446 to 2.429 is attributed to the generation of bridging oxygen atoms via the conversion of TeO3 into TeO4 units. Conversely the increase in refractive index to 2.436 is attributed to the generation of non-bridging oxygen atoms via the conversion of TeO4 into TeO3 units. From the absorption edge studies, the value of the optical band gap EIopt.. and Urbach energy (DE) have been evaluated. The value of EIopt. lies between 2.34 and 2.83eV for the indirect transition while the Urbach energy values lies between 0.005 to 1.33eV. The experimental results indicate that Nd3+/Er3+ rare earth ions co-doped in the system of zinc-tellurite glasses embaded silver nanoparticles are a good candidates for solid state laser as active medium.

In this study, the electron energy distribution function (EEDF), the electron swarm parameters , the effective ionization coefficients, and the critical field strength (dielectric strength) in binary He-H2 gas mixture which is used as cryogenic for high-temperature superconducting power applications,  are evaluated using two-term solution  of the Boltzmann equation over the range of E/N ( the electric field to gas density) from 1 to 100 Td ( 1 Td=10-17 Vcm2) at temperature 77 K and pressure 2MPa, taking into account elastic ( momentum transfer) and inelastic cross-sections. Using the electron energy distribution function (EEDF) electron swarm parameters (electron drift velocity, mean electron energy, diffusion coefficient, electron mobility, ionization and attachment coefficient) are calculated. At low reduced electric field strength E/N, the EEDF is close to Maxwellian distribution, at high E/N, due to vibrational excitation of H2, the calculated distribution function is non-Maxwellian. Besides, the Boltzmann equation analysis showed as the small mole fraction of H2 in the He-H2 mixture is increased, the electron energy distribution function EEDF shifts to lower energy region, the density-reduced ionization coefficient α/N and density-reduced effective ionization coefficient (α-η)/N decreases, whereas density-reduced attachment coefficient η/N, density-reduced critical electric field strength increases, (E/N)crt  and critical electric field Ecrt  increases. It is found that dielectric field strength depends on pressure and temperature. To confirm the validity of the two term solution of Boltzmann equation analysis, a set of elastic and inelastic cross-sections for each gas He and H2 are used to calculate the electron swarm parameters and dielectric field strength. Compared with previous experimental and theoretical literatures, the values obtained are generally in good agreement.

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