A series of blue phosphorescent iridium complexes with thermally activated delayed fluorescence and efficiency roll-off properties.

Six iridium complexes were designed and studied using the DFT approach, (ppy)Ir(pic) (1), (fppy)Ir(pic) (2), (ppy)Ir(tmd) (3), (fppy)Ir(tmd) (4), (ppy)Ir(tpip) (5) and (fppy)Ir(tpip) (6). Here ppy denotes phenylpyridine, fppy denotes 2-(2,3,4,5-tetrafluorophenyl) pyridine, pic denotes benzoic acid, tmd denotes 5-hydroxy-2,2,6,6-tetramethylhept-4-en-3-one and tpip denotes tetraphenylimido-diphosphinate. The geometries, absorptions, emissions, frontier molecular orbitals, and spin-orbit coupling (SOC) constants of the 6 complexes were evaluated.

Ascorbic acid mediated fluorescence emission of MnO modified upconversion nanoparticles for anti-counterfeiting.

Anti-counterfeiting ink can prevent important documents from being forged or tampered with. We reported a strategy to improve upconversion luminescence intensity of NaYF:18%Yb,0.5%Tm core nanoparticles (NPs) by coating the NaYF shell.

Force and Torque Model of Magnetically Levitated System with 2D Halbach Array and Printed Circuit Board Coils.

Precision machining fields often require worktables with different stroke sizes. To address the need for scalability and facilitate manufacturing, this study proposes a novel infinite expansion magnetically levitated planar motor (MLPM) based on PCB stator coils. Different from existing magnetic levitation systems that use PCB coils, the design presented in this paper utilizes smaller coil units, with each coil being independent of one another.

Spectral properties of B enhanced by small molecule adsorption.

The luminescence characteristics of small molecule excited B have not been studied yet, and it may have a potential application value in quantum dot luminescence. Herein, the adsorption and fluorescence emission spectra of small molecules (pyridine, pyrazine and benzene) adsorbed on B are studied using first-principles. The results show that the absorption of pyridine and pyrazine on B can form stable chemisorption structures pyridine-B and pyrazine-B, while benzene adsorption can form physisorption structure benzene-B.

Iterative neural network adaptive robust control of a maglev planar motor with uncertainty compensation ability.

In this paper, an iterative neural network adaptive robust control (INNARC) strategy is proposed for the maglev planar motor (MLPM) to achieve good tracking performance and uncertainty compensation. The INNARC scheme consists of adaptive robust control (ARC) term and iterative neural network (INN) compensator in a parallel structure. The ARC term founded on the system model realizes the parametric adaptation and promises the closed-loop stability.

Tuning the Red-to-Green-Upconversion Luminescence Intensity Ratio of NaScF: 20% Yb, 2% Er Particles by Changes in Size.

NaScF: 20% Yb, 2% Er samples were synthesized with different reaction times and reaction temperatures using the solvothermal method. We carried out a series of tests on Na3ScF6 crystals. The XRD patterns showed that the monoclinic phases of the NaScF samples could be synthesized under different reaction conditions, and doping with Yb ions and Er ions did not change the crystal structures.

High pressure Raman study of LiClO.

Lithium perchlorate (LiClO), as one of the new high-energy oxidizers, is chosen for high pressure Raman research to gain a better understanding of the structure and stability, which is very important for the performance of an explosive. Raman spectra of LiClO crystal have been measured from ambient to 25.07 GPa with diamond anvil cells (DACs) at room temperature to investigate the structural stability of this system.

Fatigue Fracture Analysis on 2524 Aluminum Alloy with the Influence of Creep-Aging Forming Processes.

The different creep-aging forming processes of 2524 aluminum alloy were taken as the research object, and the effects of creep-aging temperature and creep stress on the fatigue-crack propagation properties of the alloy were studied. The research results showed the following under the same sintering time of 9 h, at creep-aging temperatures of 100 °C, 130 °C, 160 °C, and 180 °C, respectively, with an increase in creep-aging temperature: the fatigue-crack propagation rate was promoted, the spacing of fatigue striations increased, and the sizes of dimples decreased while the number was enlarged; this proves that the fatigue property of the alloy was weakened. Compared with the specimens with creep deformation radii of 1000 mm and 1500 mm, the creep deformation stress was the smallest when the forming radius was 1800 mm, with a higher threshold value of fatigue-crack growth in the near-threshold region of fatigue-crack propagation (Δ ≤ 8 MPa·m).

Raman spectroscopy study of acetonitrile at low temperature.

We report the low-temperature studies of liquid CHCN by Raman spectral measurements at ambient pressure with decreasing the temperature from 20 to -196 °C. Detailed internal modes especially the lattice modes analysis revealed that the structural phase transitions of acetonitrile from liquid to solid phase β and solid phase β to solid phase α were occurring at -50 and -60 °C, respectively. Further, the Fermi resonance parameters between the fundamental ν and combination (ν + ν) of CHCN at different temperatures were calculated based on the Bertran's equations.

Tunable Ionic Liquid-Water Separation Enabled by Bioinspired Superwetting Porous Gel Membranes.

Selectively wettable porous membranes have been demonstrated to be outstanding energy-efficient materials for use in continuous liquid separation (including separating industrial oils or common organic solvents), in environmental protection, and in the chemical industry. The continuous separation of ionic liquids (ILs), which is important for chemical synthesis and chemical engineering, has been less explored. Herein, we report an on-demand liquid-passed-through strategy for the efficient and continuous separation of ILs from their aqueous solutions via the utilization of bioinspired liquid-infused porous gel membranes.

Temperature-dependent study of Fermi resonance of CHCN and CHCN---Li complex in CHCN-LiClO mixture by Raman spectroscopy.

The Raman spectra of acetonitrile-LiClO mixture solution have been measured in the temperature range 20 to -196 °C at ambient pressure. Detailed Raman spectroscopy analysis revealed that, in acetonitrile-LiClO mixture solution, the liquid CHCN transformed into solid phase β at approximately -50 °C, and then into solid phase α at approximately -60 °C. Besides, the Fermi resonance parameters of CHCN and CHCN---Li complex at different temperatures were calculated by using the Bertran's equations, respectively.

Synthesis of Small Ce-Er-Yb Tri-Doped BaLuF₅ Active-Core-Active-Shell-Active-Shell Nanoparticles with Strong Down Conversion Luminescence at 1.5 μm.

Small fluoride nanoparticles (NPs) with strong down-conversion (DC) luminescence at 1.5 μm are quite desirable for optical fiber communication systems. Nevertheless, a problem exists regarding how to synthesize small fluoride NPs with strong DC emission at 1.

Influences of donor/acceptor ratio on the optical and electrical properties of the D/A alternating model oligomers: A density functional theory study.

We adopted an ingenious method that cut out the DA alternating oligomers from the corresponding DA alternating copolymers. From analyzing the orbital compositions of the HOMOs and LUMOs as well as the reorganization energies, we found the level of charge transfer is increased with the increasing of D/A ratio, but ionization potentials and electron affinities show a contrary trend. Moreover, with the greater ratio, the trend in the nearness of two transitions results in broadening the absorption band in the visible range.

Production and evaluation of recombinant granule antigen protein GRA7 for serodiagnosis of Toxoplasma gondii infection in cattle.

The precise detection of Toxoplasma gondii infection in cattle has important public health significance. In the present study, recombinant granule antigen protein GRA7 was evaluated as a potential diagnostic marker for T. gondii infection in cattle by an indirect enzyme-linked immunosorbent assay (ELISA) using the reference serum samples determined by immunofluorescence assay and Western blotting, showing that GRA7-ELISA has a sensitivity of 96.

Theoretical study on a series of iridium complexes with low efficiency roll-off property.

A series of heteroleptic cyclometalated Ir (III) complexes for OLEDs application have been investigated theoretically to explore their electronic structures and spectroscopic properties. The geometries, electronic structures, and the lowest-lying singlet absorptions and triplet emissions of (piq)₂Ir(acac) (labeled 1) and theoretically designed models (piq)₂Ir(dpis) (labeled 2), (4Fpiq)₂Ir(dpis) (labeled 3), (4F5M-piq)₂Ir(dpis) (labeled 4), (4,5-2F-piq)₂Ir(dpis) (labeled 5) and (5-F-piq)₂Ir(dpis) (labeled 6) were investigated with density functional theory (DFT)-based approaches, where, piq=1-phenylisoquinolato, acac=acetylacetonate and dpis=diphenylimidodisilicate. Their structures in the ground and excited states have been optimized at the DFT/B3LYP/LANL2DZ and TDDFT/B3LYP/LANL2DZ levels, and the lowest absorptions and emissions were evaluated at B3LYP and M062X level of theory, respectively.

CASSCF/CASPT2 calculation of the low-lying electronic states of the CH3Se neutral radical and its cation.

Electronic states of the CH(3)Se and its cation CH(3)Se(+) have been studied using the complete active space self-consistent field (CASSCF) and multiconfiguration second-order perturbation theory (CASPT2) methods in conjunction with the ANO-RCC(TZP) basis set. To investigate the Jahn-Teller effect on the CH(3)Se radical, C(s) symmetry was used for CH(3)Se in calculations. The results show that the Jahn-Teller effect is very small (69 cm(-1)) and the 1(2)A' state is slightly more stable than the 1(2)A'' state (8 cm(-1)).

A theoretical study of the low-lying electronic states of the AlCCH radical and its ions.

The AlCCH radical is a photolysis product of the aluminum-acetylene adducts and has been considered as a molecule with potential interest in astrophysics. In this study, the low-lying electronic states of the AlCCH radical, cation, and anion have been studied by using complete active space self-consistent field and multiconfigurational second-order perturbation theory. The geometrical parameters, electron configurations, excitation energies, oscillator strengths, and harmonic vibrational frequencies are calculated in C(S) symmetry.