Luminescence and Energy Transfer Properties of Color-Tunable Dy3+, Eu3+ co-Activated NaGdSiO4 Phosphor for WLED with Great Thermo-Stability.

A series of NaGd1-x-ySiO4: y Dy3+-x Eu3+ phosphors were synthesized by a high-temperature solid-phase method. The optimal doping ion concentration of Dy3+ ions for this phosphor was determined to be 1 % from the emission spectra. The energy transfer between Dy3+ and Eu3+ ions at 351 nm was investigated by photoluminescence spectra and fluorescence decay curves. At the excitation wavelengths of 275 nm, 351 nm, 366 nm, and 394 nm, a change from yellow to white to red light can be realized by adjusting the doping concentration of Eu/Dy ions. Particularly, by testing the temperature-dependent fluorescence spectrum of the phosphor, it can be found that the luminous intensity of the phosphor is as high as 96 % when 394 nm excitation is employed at 413 K. It was the maximum at this temperature comparing with other phosphors as far as we know. The color coordinate values show that the NaGd1-x-ySiO4:×Dy3+-y Eu3+ phosphors are very close to the white light color coordinates (x=0.33, y=0.33) under 351 nm excitation. Meanwhile, the correlated color temperature is between 5062-7104 K. These results indicate that this phosphor is a promising candidate for high-quality WLED.

Effect of Dapagliflozin on Clinical Outcome after Drug-Eluting Stent Implantation in Elderly T2DM Patients: A Real-World Study.

Objective: To investigate the effect of dapagliflozin therapy on the clinical outcome of drug-eluting stent (DES) implantation in elderly patients with type 2 diabetes mellitus (T2DM). Methods: We retrospectively studied the real-world data of patients with coronary heart disease who received DES implantation in our hospital from May 2019 to May 2021. Baseline general data and laboratory results of patients were collected. All patients were followed up for two years after PCI, and the follow-up endpoints included in-stent restenosis, major adverse cardiovascular events (MACE), revascularization, rehospitalization, and all-cause mortality. Results: Compared with those before treatment, body mass index, systolic blood pressure, diastolic blood pressure, TG, TC, LDL-C, FBG, and HbA1c were decreased in both groups after treatment, while HDL-C was increased after treatment (P < 0.05). There were significant differences in BMI, systolic blood pressure, diastolic blood pressure, FBG, and HbA1c between the two groups before and after treatment. At the end of follow-up, the incidence of in-stent restenosis and MACE in the dapagliflozin group was lower than that in the nondapagliflozin group. K-M curve analysis showed a significant difference in in-stent restenosis and MACE after DES implantation between the dapagliflozin group and the nondapagliflozin group (logrankχ2 = 5.093, 4.524; P = 0.024, 0.033). Conclusion: In accurate clinical data, dapagliflozin could significantly improve the postoperative BMI, blood pressure, and blood glucose outcome of patients with T2DM complicated with coronary heart disease and positively impact in-stent restenosis and MACE.

Structure and spectral properties of Dy3+ doped CaYAlO4 single crystal.

A 2 at.% Dy3+: CaYAlO4 single crystal was grown successfully. The electronic structures of Ca2+/Y3+ mixed sites in CaYAlO4 were investigated using first-principles based on density functional theory. The effects of Dy3+ doping on the structural parameters of host crystal were studied using XRD pattern. The optical properties including absorption spectrum, excitation spectrum, emission spectra and fluorescence decay curves were thoroughly investigated. The results show that the Dy3+: CaYAlO4 crystal could be pumped by the blue InGaN and AlGaAs or 1281 nm laser diodes. Furthermore, an intense 578 nm yellow emission was obtained directly under excitation at 453 nm, meanwhile, evident mid-infrared light emitting was observed by 808 or 1281 nm laser excitation. The fitted fluorescence lifetimes of 4F9/2 and 6H13/2 levels were about 0.316 ms and 0.038 ms, respectively. It can be concluded that this Dy3+: CaYAlO4 crystal could simultaneously act as a promising medium for both solid-state yellow and mid-infrared laser outputs.

Sb2Te3 as the saturable absorber for the ∼2.0 µm passively Q-switched solid state pulsed laser.

We demonstrated a passively Q-switched Tm:YAP solid state pulsed laser based on an Sb2Te3 saturable absorber. This saturable absorber was prepared by a facile hydrothermal method. The maximum pulse energy was up to 5.366 µJ at the absorbed pump power of 6.6 W. The corresponding pulse width, output power and repetition rate were 533 ns, 542 mW and 101 kHz, respectively. The results indicated that the hydrothermally synthesized Sb2Te3 nanosheet was a promising saturable absorber for near-infrared pulsed lasers.

Passively Q-switched solid-state Tm:YAG laser using topological insulator Bi2Te3 as a saturable absorber.

We demonstrated a passively Q-switched solid-state Tm:YAG laser using topological insulator (TI) Bi2Te3 as the saturable absorber (SA) for the first time, to the best of our knowledge. The Q-switched laser pulses were obtained with the minimum pulse width of 382 ns, the maximum pulse energy of 4.8 µJ, the maximum average output power of 272 mW, and a pulse repetition rate of 57.67 kHz. The results indicate that Bi2Te3 can be a promising kind of saturable absorber in the 2 µm wavelength region.