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The development of new energy vehicles (NEVs) cannot be separated from the support of subsidy policies. However, the effectiveness of different subsidy policies remains to be verified. To investigate a more effective way of NEV subsidy and maximize the effect of subsidy policies, this study proposes two subsidy strategies, namely, consistent subsidy and adaptive subsidy, and constructs a network-based evolutionary game model for NEV diffusion. The effects of different subsidy policies are then comprehensively evaluated from the supply and demand sides, and their internal influence mechanisms are further investigated. Results show that: 1) from the supply side, subsidy for both policy achieves the highest NEV diffusion, but subsidy for enterprises is more efficient; 2) from the demand side, NEV diffusion increases NEV sales in the same proportion. Surprisingly, the increase in NEV diffusion rate benefits traditional vehicle manufacturers by expanding their average market demand; 3) from the cost-benefit analysis, the adaptive subsidy is more efficient than consistent subsidy; 4) The higher the initial benefits of NEV enterprises, the higher the level of NEV diffusion. The government should implement the adaptive subsidy and focus on providing subsidies to NEV enterprises to increase the NEV diffusion rate and achieve efficient resource allocation.

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Er(3+) doped oxyfluoride tellurite glasses have been prepared. Three Judd-Ofelt parameters Ωt (t=2, 4, 6) and radiative properties are calculated for prepared glasses. Emission characteristics are analyzed and it is found that prepared glasses possess larger calculated predicted spontaneous transition probability (39.97 s(-1)), emission cross section σem (10.18 × 10(-21)cm(2)) and σem × Δλeff (945.32 × 10(-28)cm(3)), corresponding to the 2.7 µm emission of Er(3+): (4)I11/2→ (4)I13/2 transition. The results suggest that the prepared glasses might be appropriate optical material for mid-infrared laser application. Moreover, rate equation analysis which is rarely used in bulk glass has been carried out to explain the relationship between emission intensity and Er(3+) concentration. The calculation results show that with the increment of Er(3+) concentration, the energy transfer up-conversion rate of (4)I13/2 state increases while the rate of (4)I11/2 state reduces, resulting in the change of 2.7 µm emission.

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This paper reports on the spectroscopic and structural properties in Er(3+)-doped oxyfluorotellurite glasses. The compositional variation accounts for the evolutions of Raman spectra, Judd-Ofelt parameters, radiative properties, and fluorescent emission. It is found that, when maximum phonon energy changes slightly, phonon density plays a crucial role in quenching the 2.7 µm emission generated by the Er(3+):(4)I11/2→(4)I13/2 transition. The comparative low phonon density contributes strong 2.7 µm emission intensity. The high branching ratio (18.63%) and large emission cross section (0.95×10(-20) cm(2)) demonstrate that oxyfluorotellurite glass contained with 50 mol.% TeO2 has potential application in the mid-infrared region laser.

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Er(3+) -doped germanate glasses with superior thermal stability were prepared. Judd-Ofelt intensity parameters and important spectroscopic properties were discussed in detail. Upon 800 nm and 980 nm LD pumping, 2.7 µm fluorescence characteristics were investigated and it was found that the effective 2.7 µm emission bandwidth can reach to 101.79 nm in prepared glasses. The tunability of the 2.7 µm emission band can be realized by adjusting the Er(3+) content. Moreover, a high-emission cross-section (11.09 × 10(-21) cm(2) ), large gain bandwidth (772.30 × 10(-28) cm(3) ) and gain coefficient (6.72 cm(-1) ) were obtained in the prepared sample. Hence, Er(3+) -doped germanate glass might be a promising mid-infrared material for tunable amplifiers or lasers.

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Erbium-doped germanosilicate glasses with various cerium ions contents have been prepared. Optical absorption and 1.53 µm emission spectra were measured to characterize the spectroscopic performances of prepared samples. A detailed study of 1.53 µm spectroscopic properties was carried out when pumped by an 808 nm laser diode. Moreover, an energy level diagram and an energy transfer mechanism between Er3+ and Ce3+ were proposed to elucidate the enhanced 1.53 µm fluorescence. It is found that the prepared samples have optimal spectroscopic properties when the Ce3+ concentration is fixed to 0.5 mol. %. High spontaneous radiative transition probability (172.66 s(-1)), large effective emission bandwidth (74 nm), and emission cross section (9.49×10(-21) cm(2) indicate that 808 nm pumped Er3+/Ce3+ codoped germanosilicate glass might be a suitable material for a broadband optical amplifier.

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Er(3+) doped Y2O3 and Nb2O5 modified germanate glasses with different Er(3+) concentrations were prepared. J-O intensity parameters were computed to estimate the structural changes due to the additions of Y2O3 and Nb2O5. The main mid-infrared spectroscopic features were investigated. To shed light on the observed mid-infrared radiative behavior, 975 nm and 1.53 µm emission spectra along with their decay lifetimes were also discussed. Moreover, the energy transfer processes of (4)I11/2 and (4)I13/2 level were quantitatively analyzed. In view of the experimental lifetimes, the simplified rate equation was utilized to calculate the energy transfer upconversion processes of upper and lower laser level of 2.7 µm emission. The theoretical calculations are in good agreement with the observed 2.7 µm fluorescence phenomena. Finally, the stimulated emission and gain cross sections were calculated and the results indicate that Er(3+) doped germanate glasses have great potential for mid-infrared application.

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The near infrared luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glasses have been investigated. The various effects on structure and 1.53 µm emission were analyzed as a function of Yb(3+) concentration. The energy transfer mechanism was proposed. High measured lifetime (10.75 ms), large effective full widths at half maximum (73.71 nm) and large gain per unit length (62.8 × 10(-)(24)cm(2)s) have been achieved in prepared glass. The present glass co-doped with 6mol% YbF3 and 2 mol% ErF3 showed magnificent luminescence properties for telecommunication application.

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Er(3+) doped and Er(3+)/Ce(3+) co-doped silica-germanate glasses were synthesized by high-temperature melt-quenching technique. A detailed study of the 1.53µm spectroscopic properties and thermal stability was presented in this work. The absorption spectra, 1.53µm emission spectra and fluorescence lifetimes were measured and investigated, along with the quantitative calculations and analyses of Judd-Ofelt intensity parameters, stimulated absorption and emission cross-sections and the product of FWHM×σem(p). It was found that the prepared samples have outstanding thermal stability (Tg=585°C), large FWHM (77nm and 108nm) and high stimulated emission cross-sections (9.55×10(-28)cm(3) and 8.72×10(-28)cm(3)) of Er(3+). The 1.53µm fluorescence intensity improved significantly with the introduction of Ce(3+). Furthermore, the wavelength dependent gain coefficient G(λ) of (4)I13/2→(4)I15/2 transition of Er(3+) was determined by means of the absorption and emission cross-sections. The results indicate that the developed glass co-doped with Er(3+)/Ce(3+) is a promising gain medium applied for broadband amplifier pumped with a 980nm laser diode.

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