Advanced Materials Research Vols. 557-559

Abstract: Two-photon absorption materials containing quinoline ring as electron acceptors: 9-ethyl-3-(2-quinolin)viny-carbazole (4) and 9-ethyl-3,6-bis(2-(quinolin)vinyl)–carbazole (5) have been prepared by the Vilsmeier reaction of formylation and Knoevenagel condensation. Their one-photon properties including linear absorption, fluorescence spectra, fluorescence quantum yields and fluorescence decay behaviors and the two-photon fluorescence excited by 120 fs pulse at 800nm Ti: sapphire laser operating at 1 kHz repetition rate were investigated, and two photon absorption cross-section was measured. It was showed that material 5 containing two quinoline rings as electron acceptors exhibited high two-photon absorption activity and the two-photon absorption cross-section (δTPA) was 364×10–50cm4s/photon, which was about as four times as that of material 4 containing one quinoline ring as electron acceptor (δTPA=81×10–50cm4 s/photon); material 5 possessed longer fluorescence lifetime (τ) of 21.4 ns and larger fluorescence quantum yield (Φ) of 0.81 than those of material 4 (τ=10.03 ns, Φ=0.77). Influence of chemical structure on the two-photon absorption was discussed. Based on the optical properties, sample 5 might be a promising candidate material for the application in super-high-density three-dimensional (3D) two-photon data storage and two-photon 3D nano/micro structure fabrication.

Abstract: In this study, hydrothermal reaction with Na2MoO4 and Zn(NO₃)₂ as a precursor were investigated for the synthesis of β-ZnMoO₄. The β-ZnMoO₄ were characterized by the X-ray diffractometer (XRD), electron microscopy with the field emission scanning electron microscopy with energy dispersive X-ray spectrometer (FE-SEM-EDS), high resolution X-ray photoelectron spectrometry (HR-XPS), UV-vis diffuse reflectance spectrometry (UV-DRS), and Fourier transform infrared spectrometry (FT-IR). Diffuse UV-vis spectra show the β-ZnMoO₄ materials to be indirect semiconductors with an optical bandgap of 2.48-2.64 eV. The photocatalytic efficiencies of powder suspensions were evaluated by measuring the Victoria Blue R (VBR) concentration. This is the first reveal that excellent activities of β-ZnMoO₄ are a promising visible-light-responsive photocatalyst.

Abstract: In this work, we demonstrate β-Chitosan(βCS) made from the skin of maggot has higher viscosity, better activity and lower heavy metal concentration in comparison with α-Chitosan made from shrimp shell and crab shell. This study is basedon hydroxyapatite(HA) as the matrix. The method of reverse phase suspension cross-linking was adopted in the experiment to prepare Fe₃O₄/βCS magnetic microspheres. Then magnetic Fe₃O₄/βCS/HA composite microspheres were prepared by compounding Fe₃O₄/βCS with HA via in situ precipitation method. Through our experiments, we found the concentration of βCS 1.5%, Fe₃O₄/βCS mass ratio of 9.05, and stirring speed of 1200r/min to be the optimal conditions. Furthermore, the structure and morphology of β-magnetic chitosan microspheres were analyzed with XRD and SEM, and the average particle diameters were determined to be 10μm. With the productivity of β-magnetic chitosan microspheres is above 50%, the magnetic Fe₃O₄/βCS/HA composite microspheres are expected to become promising multi-functional bone repair materials.

Abstract: The ZrC-20vol.%SiCw ultrahigh temperature ceramics with relative density of 99.2% can be prepared by hot pressing at 1900 oC and 30MPa for 60 min. The mechanical properties and microstructure of the composite were studied. The flexural strength and fracture toughness reaches up to 626.17MPa, 5.03 MPa•m1/2, respectively. SEM analysis shows the microstructure of the ZrC-20vol.%SiCw is homogeneous and SiC whiskers are uniformly distributed around the ZrC grains, which inhibit the ZrC grain growth during sintering. The fracture surface of ZrC-20vol.%SiCw reveals a mixture of intergranular and transgranular failure, and SiC whiskers play a remarkable role in improving the strength and toughness of ZrC matrix. The toughening mechanism of the composite is mainly fine-grain strengthening and whisker pull-out.

Abstract: Low temperature-quenching and high-efficiency Ca₃Sc₂Si₃O₁₂:1%Ce³⁺, x%Ba²⁺ phosphors were prepared by solid state method and the properties of these phosphors were investigated. The results showed that co-doping of Ba²⁺ ions can improve the photoluminescence properties and decrease temperature-quenching of Ca₃Sc₂Si₃O₁₂:Ce³⁺ phosphor obviously. High-efficiency blue-green light-emitting diode was fabricated with the prepared phosphor and an InGaN blue-emitting (~460 nm) chip. Good performance of the prepared LED indicates that Ca₃Sc₂Si₃O₁₂:1%Ce³⁺, 0.5%Ba²⁺ phosphor is a suitable candidate for the fabrication of high-efficiency white LEDs.

Abstract: Eu-complexed bis(2-(diphenylphosphino)phenyl)ether oxide (Eu(TTA)₃DPEPO) was synthesized. Its photoluminescence (PL) spectra peaked at 607 nm in THF, fluorescence lifetime was measured to be 459.94 μs. The highest occupied molecular orbit (HOMO) and the lowest unoccupied molecular orbit (LUMO) energy levels were -5.25 and -2.02 eV. Four multilayer devices were fabricated with different structures. The EL spectra from Eu³⁺ characteristic emission at 616 nm would be observed in all devices. The emission from Alq₃ was suppressed when BCP was inserted, the balance of charge transport could be achieved when PBD was mixed. The Commission International de L’Eclairage (CIE) coordinates were tuned from (0.36, 0.51) for Device A to (0.63,0.36) for Device D. The luminescence of Devices C and D reached up to 164 and 120 cd/m².

Abstract: ABSTRACT. The evaluation of the sintering quality of magnetic materials is an important issue. Similarity measures between curves have a broad prospect in the prediction of process industry. A new algorithm was presented in this paper to calculate the similarity between the designed process curve and the acquired one. The limitation of traditional similarity measures was avoided and the characteristics of process and the curve form were taken into account. Then, the similarity measure was applied to valuate the actual process performance of magnetic materials sintering. It shows that the proposed similarity evaluation methods can be used to effectively predict or analyze the control performance.

Abstract: Co₂Z type planar hexaferrite doping of Sr²⁺ 2CoO∙3Ba_1-xSr_xO∙10.8Fe₂O₃ is made with common production process of cermet. The paper studied the influence of Sr²⁺ doping quantity on microstructure and magnetic performance of Co₂Z type planar hexaferrite. The result indicates that when the doping quantity x=0.4, the magnetic performance in ultrahigh frequency will get improved, the initial permeability can grow to 14, and the cut-off frequency will also relatively increase to 2.45GHz.

Abstract: Recently, silver nanoparticles(NPs)-based photocatalysts have attracted more attention due to their enhanced visible light photocatalytic activity. In this work, a new Ag@Ag₃PO₄ photocatalyst have been prepared by precipitation replacement and reduction methods. The products were characterized by XRD and SEM. The photocatalytic activities was evaluated using 2-naphthol and methyl orange degradations under visible light irradiation (λ > 400 nm). The degradation rates of 2-naphthol and methyl orange with initial concentration of 15 mg•L^-1 reached 80% and 99% respectively by using 0.6 g•L^-1 Ag@Ag₃PO4. The photocatalytic mechanism was discussed.

Abstract: Several acetophenoneammonium tetraorganylborate salts as photoinitiators(PI) were synthesized by two-step method Which can dissolve in polyurethane- acrylate(PUA).Their structure were characterized by 1HNMR. The photopolymerization of B205 (bifunctionality PUA), intiated by acetophenone-ammonium tetraorganylborate salts and Darocur 1173, were studied.The results indicte that they were efficient for the polymerization but least than the Darocur 1173,and the hardness of the films were at least 3H after irradiation of UV.