Analysis of catch rates of LED lamps using on the falling-net fishing vessels in South China Sea.

Falling nets are a type of fishing gear that appeared and developed rapidly in the northern of South China Sea in the early 1990s. We have developed Light-emitting diode (LED) fishing lamps to replace metal halide (MH) lamps that reduce fuel consumption without reducing the catches. We conducted marine light-fishing experiments in the northern South China Sea during September 20 to 26, 2019 and August 29 to 31, 2021. The results in the first fishing experiment show that there is no significant change in catch of the falling-net fishing vessel when the white LED lamps (with a total power of 36 kW) were used instead of MH lamps (with a total power of 120 kW). Coleoidea catches of the falling-net fishing vessel increased significantly when white LED lamps (with a total power of 36 kW) and cyan LED lamps (with a total power of 6.0 kW) were used. The results in the second fishing experiment show that the total weight of catches of the cyan LED fishing lamps is more than that of the white LED fishing lamps, and the cyan LED light can attract Penaeus merguiensis, Thryssa dussumieri and Sardinella zunasi more effectively than the white LED light.

Luminescence properties and energy-transfer behavior of Y2-x-yBixEuyMgTiO6 phosphors.

In recent years, double perovskite has become a research hotspot of luminescent matrix materials due to its flexible structure, easy doping and good thermal stability. By using a high temperature solid-state technique, Bi3+ and Eu3+ co-doped Y2-x-yBixEuyMgTiO6 (0 ≤ x ≤ 0.1, 0 ≤ y ≤ 0.5) phosphors were made. X-ray diffraction (XRD) analysis shows that the crystal structure of all samples is monoclinic system, P21/n; Bi3+ and Eu3+ can be doped into the position of Y3+ in the substitution system of Y2MgTiO6. Both photoluminescence spectroscopy (PL) and X-ray excitation luminescence spectroscopy (XEL) were used to investigate the link between Bi3+ and Eu3+ doping concentrations and luminescence intensity. PL shows that: When 375 nm is used as the excitation wavelength, by varying the doping concentration of Eu3+ in the Y1.995-yBi0.005EuyMgTiO6 phosphor, it is possible to create the color-tunable emission from blue to red; The introduction of an appropriate amount of Bi3+ will increase the typical Eu3+ emission; The way that the system's Bi3+ and Eu3+ exchange energy can be observed by combining the fluorescence decay curve and photoluminescence. Fitting by concentration quenching model shows that the resonant dipole-dipole transition is the mechanism of energy transfer between Bi3+→Eu3+; X-rays may successfully stimulate the phosphor, and the spectral distribution of XEL and PL is basically the same; The introduction of an appropriate amount of Bi3+ is also beneficial to improving the sensitivity of XEL; Changes in temperature affect the sample's emission intensity; In addition, the samples remain stable for an extended period while being continuously exposed to X-rays at various environmental temperatures. The a forementioned findings suggest that the phosphor has potential use value in the lighting industry, X-ray imaging and temperature sensor.

Dosimetric and spectroscopic study of LiMgPO4 doped with Tm3+ and Er3.

Olivine-type phosphate LiMgPO4 doped with rare earth elements is considered a novel dosimetric material with excellent performance that is suitable for thermoluminescence (TL) and optically stimulated luminescence (OSL) measurements. Novel LiMgPO4:Tm,Er samples were synthesized by a high-temperature solid-state reaction method. A detailed study of the TL and OSL of the samples was performed using ß-ray irradiation and X-ray-excited optical luminescence (XEOL) spectroscopy. Density functional theory (DFT) calculations were performed to predict the preferential positions of thulium and erbium, and photoluminescence (PL) spectra and TL 3D spectra were analyzed. The DFT calculation results show that Mg is preferentially replaced by Tm/Er in the LiMgPO4 system. The PL/TL3D/XEOL spectra of the samples are dominated by the characteristic luminescence of Tm3+, and the OSL decay curve of photoluminescence has fast and slow decay components with decay constants of 5 s and 42 s, respectively. The TL and XEOL results show that LiMgPO4:Tm,Er has strong emission signals under different types of radiation rays. The PL/TL3D/XEOL spectral results show that Er3+ has no radiative excitation, but Tm3+ has strong luminescence, such that the sample still emits strong TL and PL signals. Two TL emission peaks occur at approximately 120 °C and 300 °C, where the high-temperature peak is significantly more intense than the low-temperature peak, promoting the stability of the TL and OSL signals of the samples. The TL curve consists of 6 general TL dynamic peaks. The nonlinear parameters of the TL dose response are R = 0.08 and D 0 = 479 Gy, and the OSL dose response is linear in the range of 0.2-1000 Gy. The TL and OSL signals of the LiMgPO4:Tm,Er phosphor have good repeatability. Therefore, the LiMgPO4:Tm,Er phosphor can be used for radiation dose measurement.

Study of thermoluminescence, photoluminescence and dosimetry for the YAGG:Ce (Y2.96Al3.4Ga1.6O12:0.04Ce) phosphor.

The comprehensive effect of ionizing radiation should be considered in the use and or analysis of certain electronic equipment. Fluorescent powders are widely used in electronic equipment, so they are attempted to be used as thermoluminescence (TL) dosimeter directly. Green YAGG:Ce phosphors were prepared by a high-temperature solid-state reaction method. The TL glow curves, TL dose response, TL three-dimensional (3D) spectra (80 K-800 K) and photoluminescence spectra for the phosphors were measured. The measurement results show that the luminescence peak temperature for the sample occurs at approximately 458 K and the luminescence peak temperatures in the TL 3D spectra are located at 130 K, 240 K and 458 K; there are four kinds of activation energies of traps in the material; the TL response of each component for the YAGG:Ce phosphor shows good linearity and the detection sensitivity of the phosphor is estimated to be less than 2 mGy. TL 3D spectra and PL spectra show that the luminescence from the phosphors arises from the 2D3/2 â†’ 2F5/2,7/2 transition of Ce ions, and the TL 3D spectra at 130 K, 240 K and 458 K are almost the same, which proves that the temperature can hardly change the relative probability of the 2D3/2 â†’ 2F5/2,7/2 transitions. The results show that YAGG:Ce could be used as dosimeter material.

Lanthanide-doped mesoporous MCM-41 nanoparticles as a novel optical-magnetic multifunctional nanobioprobe.

To research and develop potential multifunctional nanoprobes for biological application, lanthanide-doped MCM-41 (Ln-MCM-41, Ln = Gd/Eu) silica nanoparticles with excellent pore structure and optical-magnetic properties were synthesized via a facile and economical sol-gel method. The microstructure and pore distribution of Ln-MCM-41 nanoparticles were obviously affected by the Ln-doping. As the Ln/Si mole ratio increased, the specific surface area and total pore volume of Ln-MCM-41 nanoparticles rapidly decreased. However, the Ln-MCM-41 nanoparticles still retained the typical well-ordered mesoporous structure, and exhibited excellent drug release behavior. Moreover, the drug release rate of Ln-MCM-41 was remarkably pH-dependent and increased gradually upon decreasing pH. Additionally, these nanoparticles also exhibit considerable photoluminescence properties, living cells photoluminescence imaging in vitro, and paramagnetism behavior at room temperature due to the Ln3+-ions doping. Our research shows the possibility of our Ln-MCM-41 nanoparticles as multifunctional nanoprobes for application in bioseparation, bioimaging, and drug delivery.