Search

Hot-pressing of infrared transparent ZnS ceramics from nanopowders calls for proper particle size of the raw nanopowders to avoid the size-induced low-temperature sphalerite-to-wurtzite phase transition during calcination and sintering. In this paper, ZnS precipitate was solvothermally treated at 180 °C for 10–50 h. After solvothermal treatment, the particle size increased from 4 nm of the as-prepared precipitate to more than 10 nm, which results in better sphalerite phase stability. Even after calcination at 800 °C for 2 h, the major phase of the solvethermally synthesized powders kept as sphalerite phase. Due to the optically isotropic sphalerite phase, as well as the less organic impurities, the hot-pressed ceramic showed much better optical quality than that from the precipitated powders. [ABSTRACT FROM AUTHOR]

Transparent Fe 2+ :ZnS polycrystals are 3–5 μm mid-IR laser gain materials with great importance. In this paper, a novel route combining wet-chemical co-precipitation, hot-pressed sintering and post hot isostatic pressing (HIP) treatment was proposed for Fe 2+ :ZnS transparent ceramics. Fe 2+ :ZnS powders were synthesized successfully by the wet-chemical co-precipitation method, which was suitable for particle size and morphology controlling and then ceramics consolidation. Transparent Fe 2+ :ZnS ceramics with comparatively high optical quality were successfully fabricated by two step sintering method combining hot pressing and post-HIP treatment. This approach is a promising candidate for fabricating Fe 2+ :ZnS ceramics with large size, low cost, short cycle, and flexible concentration distribution design. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a common foodborne pathogen found in aquatic products and represents a major threat to human health worldwide. Though not all this bacteria were harmful to human beings, the pathogenic V . parahaemolyticus always harbors either tdh (the thermostable direct hemolysin) or trh (TDH-related hemolysin) gene, or both. Additionally, the extensive use of antibiotics has been shown to be a contributing factor to the increasing incidence of antimicrobial-resistant strains. In this study, thirty-one clinical isolates were examined and compared with 95 (38.0%) aquatic product isolates (fishes, n = 28; shrimps, n = 67) collected from 250 samples in Guangdong, China. All isolates were studied by antibiotic susceptibility analysis, tdh and trh genes detection, serotyping and molecular typing (ERIC-PCR). The antimicrobial resistance patterns of these aquatic product isolates to 12 antimicrobial agents revealed that most of the isolates were resistant to streptomycin (90.53%). The isolates were also resistant to follow by ampicillin (33.68%) and cephalothin (30.53%). For clinical isolates, they were resistant to streptomycin (93.55%), ampicillin (87.10%), and cefazolin (64.52%). All isolates showed no resistance to azitromycin, chloramphenicol, ciprofloxacin, or nalidixic acid. The clinical isolates were positive for tdh (100%) and trh gene (77.42%), with ratios of only 2.11% and 28.42%, respectively in the aquatic product isolates. Serotyping detected shown that the isolates contained O1, O2, O3, O4, and O11, with the O3 serotype being the most common among the clinical isolates (48.39%), while the O2 (41.05%) makes the maximum proportion on aquatic product isolates. ERIC-PCR results demonstrated the isolates (n = 126) were classified into eight clusters, revealing genetic variation and relatedness between clinical and aquatic product isolates. This study provided a foundation for understanding the distinction between aquatic product and clinical isolates and yielded basic information for achieving food safety through control of V . parahaemolyticus contamination. [ABSTRACT FROM AUTHOR]

A novel magneto-optical material, (Tb 0.995 Ho 0.005 ) 3 Al 5 O 12 transparent ceramic, was successfully fabricated using co-precipitated powders. The prepared (Tb 0.995 Ho 0.005 ) 3 Al 5 O 12 ceramic exhibits outstanding optical quality and magneto-optical property. For the (Tb 0.995 Ho 0.005 ) 3 Al 5 O 12 ceramic pre-sintered at 1650 °C for 20 h with HIP post-treatment at 1700 °C for 3 h, the optical transmittance exceeds 80% in the 500–1500 nm region (except for the absorption bands). The Verdet constant of the sample at 633 nm is about 1.4 times higher than that of the commercial Tb 3 Ga 5 O 12 single crystal. High transparency and Verdet constant make it an attractive magneto-optical material for the high-power Faraday isolators. [ABSTRACT FROM AUTHOR]

Highly transparent aluminum oxynitride (AlON) ceramics were fabricated by pressureless sintering with hot isostatic pressing (HIP) post-treatment. The experimental results showed that the optical transparency of AlON ceramics was improved markedly over the visible and near-infrared range by HIP at 1825 °C for 3 h in 200 MPa argon gas, which derived from the elimination of residual pores in the prepared ceramics. For AlON ceramics pre-sintered at 1800 °C, the transmittances of the sample increased from 63.6% to 84.8% at 600 nm and from 75.4% to 86.1% at 2000 nm, respectively. The average grain size of the HIPed sample was about 47.9 μm. [ABSTRACT FROM AUTHOR]

In order to enhance Ni-EDTA decomplexation and Ni recovery via photoelectrocatalytic (PEC) process, TiO 2 /Ni-Sb-SnO 2 bifunctional electrode was fabricated as the photoanode and activated carbon fiber (ACF) was introduced as the cathode. At a cell voltage of 3.5 V and initial solution pH of 6.3, the TiO 2 /Ni-Sb-SnO 2 bifunctional photoanode exhibited a synergetic effect on the decomplexation of Ni-EDTA with the pseudo-first-order rate constant of 0.01068 min−1 with 180 min by using stainless steel (SS) cathode, which was 1.5 and 2.4 times higher than that of TiO 2 photoanode and Ni-Sb-SnO 2 anode, respectively. Moreover, both the efficiencies of Ni-EDTA decomplexation and Ni recovery were improved to 98% from 86% and 73% from 41% after replacing SS cathode with ACF cathode, respectively. Influencing factors on Ni-EDTA decomplexation and Ni recovery were investigated and the efficiencies were favored at acidic condition, higher cell voltage and lower initial Ni-EDTA concentration. Ni-EDTA was mainly decomposed via ·OH radicals which generated via the interaction of O 3 , H 2 O 2 , and UV irradiation in the contrasted PEC system. Then, the liberated Ni2+ ions which liberated from Ni-EDTA decomplexation were eventually reduced to metallic Ni on the ACF cathode surface. Finally, the stability of the constructed PEC system on Ni-EDTA decomplexation and Ni recovery was exhibited. [Display omitted] [ABSTRACT FROM AUTHOR]

Ce,Ca:LuAG scintillation ceramics with different Ca2+ co-doping concentrations were prepared by the solid-state reaction method. The concentration of Ce3+ was fixed at 0.3 at% and the concentration of Ca2+ ranged from 0 to 1.2 at%. We systematically studied how the Ca2+ concentration affects the optical quality of Ce,Ca:LuAG ceramics by influencing the microstructure in the vacuum sintering and HIP post-treatment. Good optical transmittance could be obtained with Ca2+ concentrations between 0.05 and 0.8 at%, which reached 76.0–81.9 % at 520 nm. The PL and scintillation decay times decrease with increasing Ca2+ concentration up to 0.6 at% with no clear trend above this value. The light yield (LY) values at different shaping times decrease with increasing Ca2+ concentration but the fast scintillation component (LY 0.5 μs / LY 3.0 μs) increases significantly from 79 % to 97 %. The co-doping of Ca2+ also reduces the afterglow level by more than one order of magnitude. • Ce,Ca:LuAG scintillation ceramics were fabricated by the two-step sintering method. • A wide range of Ca2+ co-doping concentration was systemically investigated. • Scintillation decay accelerate with increasing Ca2+ concentration up to 0.6 at%. • Ca2+ co-doping optimizes the fast scintillation component from 79 % to 97 %. [ABSTRACT FROM AUTHOR]

• Tb 2 Ti 2 O 7 transparent ceramics were fabricated from co-precipitated nano-powders by two-step sintering. • The in-line transmittance of Tb 2 Ti 2 O 7 ceramics reaches 65.5 % at 1064 nm. • The Verdet constant of Tb 2 Ti 2 O 7 ceramics (−229.0 ± 0.6 rad·T−1 m−1@633 nm) is 71 % higher than TGG crystals. • Tb 2 Ti 2 O 7 ceramics are very promising magneto-optical materials for Faraday isolators. Transparent Tb 2 Ti 2 O 7 magneto-optical ceramics were fabricated from co-precipitated nano-powders by vacuum pre-sintering with hot isostatic pressing (HIP) post-treatment. The formation of pyrochlore phase, decomposition of the precursor, and the morphology of powders calcined at different temperatures were investigated. The in-line transmittance of Tb 2 Ti 2 O 7 ceramics, which were pre-sintered at 1350 ℃ for 2 h with HIP post-treatment at 1450 ℃ for 3 h and subsequently annealed at 800 ℃ for 20 h in NH 3 atmosphere, reaches 65.5 % at 1064 nm. The Verdet constant of Tb 2 Ti 2 O 7 ceramics is −229.0 ± 0.6 rad·T−1 m−1 at the wavelength of 633 nm, which is 71 % higher than that of the commercial Tb 3 Ga 5 O 12 crystals. Tb 2 Ti 2 O 7 magneto-optical ceramics show a promising application for Faraday rotators. [ABSTRACT FROM AUTHOR]

Ho 2 O 3 transparent ceramics were fabricated by vacuum pre-sintering combined with hot isostatic pressing (HIP) post-treatment at relatively low temperature from high-purity Ho 2 O 3 powder calcined at 1000 °C for 4 h. The optimal Ho 2 O 3 ceramic sample prepared by vacuum pre-sintering at 1250 °C and HIP post-treating at 1450 °C has a dense microstructure with average grain size of 0.77 μm, and the in-line transmittances reach 80.7 % at 1550 nm and 76.7 % at 1064 nm. The effect of air annealing on the optical quality of Ho 2 O 3 ceramics was studied, and the existence of compressed pores in the HIP-ed Ho 2 O 3 ceramics was confirmed. The Verdet constants of Ho 2 O 3 ceramics were measured to be -47.4 rad/(T m at 1064 nm and -15.4 rad/(T m at 1561 nm. High transmittance and large Verdet constant in the wavelength regions 1–1.07 μm, 1.3–1.5 μm make Ho 2 O 3 transparent ceramics promising for magneto-optical devices for lasers based on Yb-, Nd-doped materials and telecom lasers. [ABSTRACT FROM AUTHOR]

We report on the spectroscopic and laser emission properties of 10 at% Yb:Y 3 Sc x Al 5-x O 12 (Yb:YSAG) ceramic varying the amount of Sc (x) ranging from x = 0.25 to x = 1.5. The samples were fabricated by a solid state reaction method followed by vacuum sintering and annealing in air. The spectroscopic investigation has evidenced an increased broadening in both the absorption and the emission spectra for increasing Sc content, as well as an extension of lifetime at increased Sc content. Concerning the laser performance, the maximum slope efficiency, i.e. 76.6%, was obtained with the sample with x = 0.25 while the largest tuning range, i.e. 81 nm, with the sample having the highest concentration of Sc ions (x = 1.5); a steady broadening in the tuning bandwidth for increasing Scandium content was measured. [ABSTRACT FROM AUTHOR]

(Tb 0.99 Ce 0.01) 3 Ga 5 O 12 powders were synthesized by calcining the co-precipitated precursor at 1150°C. The powders showed low-agglomeration and high sinterability, so that the powders compact could be sintered to be transparent by a two-step sintering method. By using the best synthesis condition of air pre-sintered at 1525°C for 3 h and hot isostatic pressed at 1500°C for 3 h under 150 MPa, (Tb 0.99 Ce 0.01) 3 Ga 5 O 12 transparent ceramics with the in-line transmittance of 81.7% at 1064 nm were successfully prepared. The Verdet constant of the (Tb 0.99 Ce 0.01) 3 Ga 5 O 12 ceramics at 633 nm was about −143.4 ± 3.2 rad T−1 m−1, which was about 7% higher than that of the Tb 3 Ga 5 O 12 crystals (−134 rad T−1 m−1). Image, graphical abstract [ABSTRACT FROM AUTHOR]

8.7 mol% Y 2 O 3 -ZrO 2 (Y 0.16 Zr 0.84 O 1.92) precursor was synthesized by the co-precipitation method using ammonia as the precipitant. The Y 0.16 Zr 0.84 O 1.92 powders calcined at 800 °C show a pure c-ZrO 2 phase. The average crystallite size of the powders is 12.4 nm and weakly agglomerated to an average particle size of 15.5 nm. Y 0.16 Zr 0.84 O 1.92 transparent ceramics were then successfully fabricated by pre-sintering at 1350 °C for 2 h and HIP post-treatment at 1750 °C for 1 h under 200 MPa without sintering additives. The in-line transmittance of Y 0.16 Zr 0.84 O 1.92 ceramics (1 mm thick) exceeds 50.3% in the region of 400–850 nm, reaching about 65.3% at 800 nm. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Pr:Lu 3 Al 5 O 12 transparent ceramics with different doping concentrations (0% − 1 at%) were fabricated using the solid-state reaction and vacuum sintering method. The influence of doping concentration on the luminescent properties was investigated in detail. The 5d-4f emission slightly redshifts with the increase of doping concentration under UV light and X-ray excitation. The slow emission below 290 nm related to antisite defects can be suppressed by the increase of doping concentration at room temperature. The suppression of exciton related emission around 250 nm at 77 K is remarkable. The 0.3 at% Pr doped ceramics show the highest light yield that is 6900 ph/MeV with 1 μs shaping time under the excitation of γ-rays (137Cs). There exists slow components of scintillation process in all the Pr-doped transparent ceramics. Higher doping concentration was found to be beneficial for the suppression of the slow components in the scintillation response and therefore acceleration of the scintillation decay and light yield increase up to certain level. These effects are mainly due to competition of Pr3+ ions with the antisite defects for charge carrier capture in the scintillation process which is also supported by the trends observed in the TSL measurements. [ABSTRACT FROM AUTHOR]