Due to the high transparency, high Verdet constant, as well as easy processing properties, rare-earth ion-doped glasses have demonstrated great potential in magneto-optical (MO) applications. However, the variation in the valence state of rare-earth ions (Tb 3+ to Tb 4+ ) resulted in the decreased effective concentration of the paramagnetic ions and thus degraded MO performance. Here, a strategy was proposed to inhibit the oxidation of Tb 3+ into Tb 4+ as well as improve the thermal stability by tuning the optical basicity of glass networks. Moreover, the depolymerization of the glass network was modulated to accommodate more Tb ions. Thus, a record high effective concentration (14.19 × 10 21 / cm 3 ) of Tb ions in glass was achieved, generating a high Verdet constant of 113 rad/(T•m) at 650 nm. Lastly, the first application of MO glass for magnetic field sensors was demonstrated, achieving a sensitivity of 0.139 rad/T. We hope our work provides guidance for the fabrication of MO glass with high performance and thermal stability and could push MO glass one step further for magnetic sensing applications.

There are numerous vital usages for mid-infrared (MIR) lasers in satellite communication, biomedicine, military, remote sensing, and environmental monitoring. In this work, a progression of Er 3+ ions doped, Er 3+ /Pr 3+ ions codoped Ga 5 Ge 20 Sb 10 S 65 glasses were prepared, and their physical performances and structural characteristics were examined. To understand the non-phononassisted energy transfer mechanism, we recorded the up-conversion and infrared fluorescence emission spectra by pumping with a commercial 980 nm LD. Then the 2.7 µm strong fluorescence signal intensity can be obtained when the doped concentration of Pr 3+ is proper. After the doping of Pr 3+ , fluorescence lifetime results revealed that the lifetimes of the Er 3+ : 4 I 13/2 level fell dramatically from 7.33 to 1.90 ms, which experienced a much more significant decrease in lifetimes than the Er 3+ : 4 I 11/2 level. The MIR fluorescence performances were assessed by the determined J-O parameters and relative emission cross sections. Additionally, the generally huge emission cross sections and the small pump energy show that it is possible to obtain population inversion with relatively small pump energy; thus the Er 3+ /Pr 3+ glasses have great potential to be 2.7 µm laser materials. K E Y W O R D S2.7 µm emission, chalcogenide glass, Er 3+ /Pr 3+ co-doped, Ga 5 Ge 20 Sb 10 S 65 glass INTRODUCTIONRecently, mid-infrared (MIR) lasers about 3 µm certainly stand out enough to be noticed owing to their various useful applications, for example, military countermeasures, remote detecting, environment contamination checking, satellite correspondence, and clinical-medical procedure. [1][2][3][4][5] According to previous studies, Er 3+ is a good candidate material for 2.7 µm MIR emission due to its radiative transition of 4 I 11/2 → 4 I 13/2 . Additionally, with a 980 nm business laser, Er 3+ tends to be easily pumped. [6][7][8] However, it is as yet a critical difficulty to get the productive 2.7 µm emission because of the self-terminating issue; thus, the 4 I 13/2 level has a larger lifetime than the 4 I 11/2 level. Through energy transfer (ET), Pr 3+ , Ho 3+ , Yb 3+ , and Tm 3+ have been added as sensitizers to extinguish the Er 3+ : 4 I 13/2 level, which helps solve the issue of self-terminating.Given that the non-phonon-assisted ET process is a more effective way of quenching the electrons of 4 I 13/2 levels compared with the phonon-helped one. The energy

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In order to explore the feasibility of natural gas (NG)/diesel dual‐fuel engine with high NG substitution rate under medium and low load, the effects of hydrogen (H2) on the performance and emissions of the engine are studied numerically. The baseline engine is a four‐cylinder turbocharged diesel engine, which is modified into a diesel‐Natural Gas‐Hydrogen ternary fuels engine with port‐injected H2 and NG fuels and direct‐injected diesel fuel. The simulation is performed using GT‐Power software, and numerical results are validated with the experimental data. The percentage of diesel fuel is set at 10% and 20% (by energy). The engine speed decreases from high speed to medium speed and finally to low speed. The engine load decreases from medium load to low load. The H2 mixing ratio increases from 10% to 50%. The results show that, with the increase of H2 mixing ratio, the peak cylinder pressure (PCP), the peak cylinder temperature (PCT), the heat release rate (HRR) and the maximum pressure rise rate (MPRR) increase, while the indicated thermal efficiency (ITE) decreases under all working conditions. Among them, the MPRR increases by 4%~13% at medium load and 1%~2% at low load, but it does not exceed 0.6 MPa/ (°) CA. The indicated thermal efficiency decreases by 1%~4% at medium and low load. In terms of emissions, the carbon monoxide (CO) and the hydrocarbons (HC) decrease by 34%~43%, but the nitrogen oxide (NOX) increases by 58%~73%.

In order to improve of high loaded diesel engine with high ethanol substitution rate, the effects of intake temperature on the combustion characteristics and generation characteristics of pollutants in cylinder from reactivity controlled compression ignition (RCCI) engine under high load was studied numerically. RCCI experimental data were obtained from a four cylinder turbocharged diesel engine fuel modified to run with diesel/ethanol dual fuel in the study. The simulation was performed via converge computational fluid dynamics (CFD) code, and numerical results were validated with the experimental data. The parameters such as cylinder pressure, cylinder temperature, heat release rate (HRR), CA10, CA50, indicated thermal efficiency, maximum pressure rise rate, NOx, soot, HC and CO emissions were investigated at 2000 rpm engine speed and high engine load (80% full load). The results show that decreasing intake temperature reduces the peaks of cylinder pressure and cylinder temperature, the HRR profile changes from double peak to single peak; the CA10 and the CA50 is retarded; maximum pressure rise rate and indicated thermal efficiency decrease. In addition, with the decreasing of intake temperature, the peaks of NOx, soot and CO generated in cylinder decreases, while the peaks of unburned HC generated in cylinder almost remain constant. Thus it can be seen that using optimal intake temperature is an effective way to improve ethanol substitution rate of diesel engine under high load.