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A series of color tunable NaCa2-xMg2 (VO4)3 : xEu3+ (0≤x≤0. 10) phosphors were synthesized by molten salt method using cheap NaCl as molten salt. The effects of synthesis conditions and Eu3+ doping on the structure and luminescence properties of the samples were investigated in details. The results show that the optimum reaction conditions for the synthesis of NaCa2Mg2 (VO4)3 are reaction temperature of 800 °C, reaction time of 0. 5 h and mass ratio of raw material to molten salt of 1:3. The obtained samples are NaCa2Mg2 (VO4)3 pure phase with higher crystallinity. The micromorphology of the samples changed from coral-like to smooth irregular polyhedron with the increase of temperature. Eu3+ doping has little effect on the crystal structure of NaCa2 Mg2 ( VO4)3, but great effect on its luminescence properties. With the increase of Eu3+ concentration (x), the characteristic emission band intensity of VO43- gradually decreases, while the characteristic emission peak intensity of Eu3+ first increases and then decreases, reaching the maximum when x = 0. 06. Therefore, the luminous color of the samples can be modulated by changing the Eu3+ concentration, from green to yellow-green, yellow, yellow-white and orange-red. According to the fluorescence spectrum and fluorescence lifetime analysis, it is confirmed that the energy transfer process of VO43-to Eu3+ exists in NaCa2 Mg2 (VO4)3 : Eu3+ phosphors, and the energy transfer efficiency is about 23%. The thermal stability analysis shows that when the temperature increases from room temperature (298. 15 K) to 398. 15 K, the retaining ratio of the main emission peak intensity of NaCa2 Mg1. 94 (VO4)3:0. 06Eu3+ phosphor at 614 nm is 68. 4%, showing its good thermal stability. [ABSTRACT FROM AUTHOR]

In this work, Cu and Cu55Ni45 thin films with a thickness of 600 nm were firstly deposited on single crystal Si and Al2O3 ceramic substrates by magnetron sputtering respectively. Then, the thin film thermopiles composed of 200 pairs of in-series thermocouples were fabricated by microfabrication technology in 10 mm x 10 mm substrate area. Finally, aluminum oxide layers were deposited by reactive magnetron sputtering as thermal resistance layers, with the help of hard mask. The different thickness of the aluminum oxide layer produces the cold and hot ends in the thin film thermopile, giving rise to a voltage under the irradiation of heat flux by the Seebeck effect, realizing the measurement of heat flux. The thin film thermopiles were analyzed and calibrated. The results show that in the Cu/Cu55Ni45 thermopiles deposited on the Si substrate and Al2O3 ceramic substrate, the roughness of the Cu films are 20 and 60 nm, the roughness of Cu55Ni45 films are 15 and 20 nm, the electrical resistance of thermopiles are 38. 2 Ω and 2. 83 kΩ, the sensitivity of thermopiles are 0. 069 45 and 0.026 97 mV/(kW ⋅ m-2), respectively. The surface roughness of Cu/Cu55Ni45 thermopiles deposited on single crystal Si substrate and Al2O3 ceramic substrate with different surface roughness will be affected, resulting in the difference in electrical resistance of thin film thermopile. In addition, the output thermoelectric voltage exhibits a good linear relationship with heat flux. [ABSTRACT FROM AUTHOR]