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In this article, 5 at.% Yb:Lu2O3 transparent ceramics were fabricated by vacuum sintering combined with hot isostatic pressing (HIP) posttreatment using co‐precipitated nano‐powders. The influence of precipitant molar ratio, ammonium hydrogen carbonate, to metal ions (AHC/M3+, R value) on the properties of Yb:Lu2O3 precursors and calcined powders was investigated systematically. It was found that the powders with different R value calcined at 1100°C for 4 hours were pure cubic Lu2O3 but the morphologies of precursors and powders behaved differently. The opaque samples pre‐sintered at 1500°C for 2 hours grew into transparent ceramics after HIP posttreatment at 1750°C for 1 hour. The final ceramic with R = 4.8 showed the best optical quality with the in‐line transmittance of 79.7% at 1100 nm. The quasi‐CW laser operation was performed at 1034 nm and 1080 nm with a maximum output power up to 8.15 W as well as a corresponding slope efficiency of 58.4%. [ABSTRACT FROM AUTHOR]

The 0.05 at.% Co:MgAl2O4 precursor was synthesized by the coprecipitation method from a mixed solution of magnesium, aluminum, and cobalt nitrates using ammonium carbonate as the precipitant. 0.05 at.% Co:MgAl2O4 transparent ceramics were successfully obtained via vacuum sintering and hot isostatic pressing (HIP) of 0.05 at.% Co:MgAl2O4 nanopowder calcined at 1100°C for 4 hours. The properties of powder and ceramics were comprehensively investigated. X‐ray diffraction (XRD) results showed that Co:MgAl2O4 nanopowder had a pure spinel phase. Also, the in‐line transmittances of the HIP posttreated Co:MgAl2O4 ceramics with the thickness of 1.2 mm were 82% at 400 nm and 84.7% at 900 nm. The average grain sizes of 0.05 at.% Co:MgAl2O4 ceramics before and after the HIP posttreatment were 11 and 28 μm, respectively. The calculated ground state absorption cross section of 0.05 at.% Co:MgAl2O4 ceramics was 2.9 × 10−19 cm2, indicating that this ceramics is a promising material applied as a saturable absorber for passive laser Q‐switches in the 1.3‐1.7 μm domain. [ABSTRACT FROM AUTHOR]

Using the tape casting method combined with vacuum sintering and hot isostatic pressing, high‐quality planar waveguide YAG/10 at.%Yb:YAG/YAG ceramics were successfully prepared. For the sample presintered at 1750°C for 30 hours and then HIPed at 1700°C for 3 hours in 200 MPa argon, the in‐line transmittance reached 82.5% at 400 nm and the average grain size was ~17.1 μm. The diffusion behaviors of Yb ions across the contact boundary between the cladding YAG layer and the core Yb:YAG layer were determined by Fick's second law. Then, a 1030 nm continuous‐wave (CW) Yb:YAG planar waveguide ceramic laser based on the structure of master oscillator power amplification (MOPA) was realized. After a single‐pass amplification, the maximum output of the ceramic slab (60 × 10 × 1 mm3) reached 1251 W and the corresponding optical‐to‐optical efficiency was 30.0%, which is the highest output power of a Yb:YAG planar waveguide ceramic laser to the best of our knowledge. [ABSTRACT FROM AUTHOR]

Ho:Lu3Al5O12(Lu AG) transparent ceramics are potential 2 μm eye-safe laser materials. Polycrystalline 0.8 at.% Ho:Lu AG ceramics with high optical quality were successfully fabricated by solid-state reactive sintering of high-purity oxide powders. The microstructure, the optical transmission, the spectrum characteristic, and the laser performance were investigated in this paper. The average grain size of Ho:Lu AG ceramics vacuum sintered at 1830°C for 30 hour is about 14 μm. The in-line transmittance of the sample is measured to be 81.7% and 82.0% at 1000 and 2250 nm, respectively. The absorption and the emission cross sections are calculated to be 0.88 × 10−20 cm2 at 1906 nm and 1.26 × 10−20 cm2 at 2094 nm. Using a thulium-doped yttrium-lithium-fluoride (Tm: YLF) laser with the central wavelength of 1907.5 nm as the pump source, 2.67 W continuous wave ( CW) laser operation at 2100.74 nm was obtained with a slope efficiency of 26.5%. The beam quality factor M2 was calculated to be 1.1, which indicated nearly diffraction-limited beam propagation and the laser was the fundamental TEM00 Gaussian mode. [ABSTRACT FROM AUTHOR]

Spring water is an important direct drinking water resource. Enterococcus faecalis is a significant opportunistic pathogen from environment that causes human neonatal sepsis and urinary tract infections. Our study investigated the prevalence, virulence genes, antimicrobial resistance, and molecular characterization of E. faecalis from spring water in Guangdong, China. A total of 285 spring water samples were collected from January 2017 to January 2018, in which 47 (16.49%) samples were contaminated by E. faecalis. Antimicrobial susceptibility result showed that many isolates were resistant to tetracycline (93.6%), gentamicin (29.8%), and ciprofloxacin (25.5%). The virulence gene test revealed the positive rate of gelE, asa1, ace, and cylA were 100, 82.3, 76.6, and 70.2%, respectively. Enterobacterial repetitive intergenic consensus‐polymerase chain reaction and multilocus sequence typing classified 47 isolates into 12 and 5 clusters, respectively, which revealed the genetic relatedness and diversity. This finding illustrated the presence of virulence genes and provided understanding on the spread of antibiotic‐resistant and genetic diversity isolates. It can help us gradually increase our knowledge of microbiological risk management in E. faecalis from spring water. Practical applications: Investigating the prevalence of Enterococcus faecalis isolates from spring water could increase this microbial safety ondrinking water. In our research, antibiotic susceptibility, virulence genes, serotypingand molecular characteristic were selected to thorough comparison among Enterococcus faecalis isolates. Spring water is common in China as drinking water, then understanding the dissemination and monitoring the prevalence of this microorganism is necessary to improve the drinking water safety. [ABSTRACT FROM AUTHOR]

Carbon aerogel (CA) cathode was adopted to an undivided-chamber photoelectrocatalytic system with TiO 2 nanotube arrays (TNA) photoanode to enhance the oxidation of hypophosphite (H 2 PO 2 −) and simultaneous recovery of metallic nickel (Ni). Both the efficiencies of H 2 PO 2 − oxidation and Ni recovery were significantly enhanced after replacing Ti or carbon fiber paper cathode with CA cathode. With 1.0 mM H 2 PO 2 − and 1.0 mM Ni2+, the ratio of PO 4 3− production increased from ∼41% or ∼54% to ∼100%, and the ratio of Ni recovery increased from ∼20% or ∼ 37% to ∼93% within 180 min at 3.0 V. H 2 PO 2 − was finally oxidized to PO 4 3− by •OH radicals, which was speculated to be generated from UV/H 2 O 2 and bound on TNA photoanode. Meanwhile, Ni2+ was eventually electro-reduced to metallic Ni by a two-electron reduction reaction. The efficiencies of H 2 PO 2 − oxidation and Ni recovery were favored at higher cell voltage, faintly acid conditions and larger H 2 PO 2 − concentration. The stability of this system exhibited that the ratio of PO 4 3− production increased significantly in each cycle, which was attributed to the increase of H 2 O 2 in-situ-generation via CA cathode caused by deposition of metallic Ni. Finally, the treatment of actual electroless nickel plating effluents was demonstrated. [Display omitted] • H 2 PO 2 − oxidation and Ni recovery were largely enhanced via carbon aerogel cathode. • The pathways of H 2 PO 2 − oxidation by •OH radicals and Ni2+ deposition were proposed. • Oxidation of H 2 PO 2 − and cathodic deposition of metallic Ni were mutually promoted. • The treatment of actual electroless nickel plating effluents was demonstrated. [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]

Terbium gallium garnet (TGG) ceramics were fabricated by air sintering and successive HIP post-treating from the TGG nanoparticles synthesized via the co-precipitation technique. The influences of the calcination temperature on the phase and morphology evolution of the nano-powders, as well as the optical transparency and microstructure of the obtained TGG ceramics were investigated in detail. The powders calcined at 1100–1250 °C retained the TGG phase purity and displayed significantly less agglomeration. Using the above powders as raw materials, the TGG ceramics pre-sintered at 1500 °C for 3 h in air and then HIP post-treated at 1550 °C for 3 h under 150 MPa argon gas showed the similar optical qualities and the in-line transmittances were about 70% at 1064 nm. The Verdet constants of all the ceramics were calculated to be about 137 rad T−1 m−1 at room temperature, which were nearly independent of the optical quality of the ceramics. • TGG ceramics were prepared by two-step sintering from the co-precipitated powders. • The optimum calcination temperature for the transparent ceramics was demonstrated. • The in-line transmittance of the fabricated TGG ceramics is 70% at 1064 nm. • The TGG ceramics show the similar Verdet constant with the commercial TGG crystals. [ABSTRACT FROM AUTHOR]

Abstract Planar waveguide LuAG/10 at.%Yb:LuAG/LuAG laser ceramics were fabricated by the tape casting method combined with the vacuum pre-sintering and hot isostatic pressing (HIP) post-treatment. The morphologies of the raw materials, tapes and green bodies were observed. The microstructure, optical transmittance and the Yb3+ ions distribution of the LuAG/10 at.%Yb:LuAG/LuAG ceramics with different pre-sintering temperatures after HIP post-treatment were mainly studied. The experimental results showed that the average grain size and in-line transmittance of the HIPed ceramics increased with the increase of pre-sintering temperature. For the LuAG/10 at.%Yb:LuAG/LuAG ceramics pre-sintered at 1825 °C for 20 h and then HIPed at 1700 °C for 3 h under 200 MPa Ar atmosphere, the in-line transmittance of the sample with the thickness of 2 mm was about 74% at 1100 nm and the maximum diffusion distance of Yb3+ was about 166 μm. The bulk and grain boundary diffusion coefficients of Yb3+ ions for the samples pre-sintered at 1775 °C–1825 °C after HIP post-treatment were calculated by Fick's second law by using the LA-ICP-MS. What's more, CW laser at 1030 nm was demonstrated and the maximum output power of 0.4 W with a slop efficiency of 9.4% was achieved. Highlights • Planar waveguide LuAG/10 at.%Yb:LuAG/LuAG laser ceramics were fabricated by the tape casting and two-step sintering method. • Laser oscillation of planar waveguide LuAG/Yb:LuAG/LuAG ceramics was demonstrated for the first. • The diffusivity of Yb3+ increased with increasing the pre-sintering temperature, especially for the grain boundary diffusion. [ABSTRACT FROM AUTHOR]

Abstract Terbium gallium garnet (TGG) precursor was synthesized by the co-precipitation method from the mixed solution of terbium and gallium nitrates using ammonium hydrogen carbonate (AHC) as the precipitant. Fine and low-agglomerated TGG powders with the average particle size of 158 nm were obtained by calcining the precursor at 1100 °C for 4 h. Then, TGG transparent ceramics were successfully fabricated by a new two-step sintering method. The TGG ceramics pre-sintered at 1500 °C for 3 h in air and then HIP post-treated at 1550 °C for 3 h under 150 MPa argon gas showed the best optical quality and the in-line transmittance was 80.3% at 1064 nm. The Verdet constant of the TGG ceramic at 633 nm was about 136.8 rad T−1 m−1, which was rather close to that of the commercial TGG single crystal. High transparency and high Verdet constant make it an attractive alternative for the high-power Faraday isolators. Highlights • TGG powders with an average particle size of 158 nm were synthesized by a co-precipitation method. • TGG ceramics with the in-line transmittance of 80.3% at 1064 nm were prepared by two-step sintering. • The fabricated TGG magneto-optical ceramics show the similar Verdet constant with the commercial TGG crystals. [ABSTRACT FROM AUTHOR]

Using the 1 at.% Er:SrF 2 nano-powders synthesized by the co-precipitation method as starting powders, 1 at.% Er:SrF 2 transparent ceramics were successfully prepared by air pre-sintering at different temperatures for 2 h combined with hot isostatic pressing (HIP) post-treatment at 600 °C for 2 h under 100 MPa Ar. The influences of the pre-sintering temperature on optical quality, microstructure, phase composition and EPR spectrum of ceramics were investigated. Among all the HIP post-treated 1 at.% Er:SrF 2 ceramics in the thickness of 2.5 mm, the sample pre-sintered at 650 °C shows the best optical quality, whose transmittance at 2500 nm and 1500 nm reaches 83.4% and 73.6%, respectively. Furthermore, the spectral characteristics of this ceramic sample were systematically analyzed. The fluorescence lifetime for the 1 at.% Er:SrF 2 ceramics at 1530 nm is 49.62 ms. The strongest absorption and emission cross section for the peaks at around 1530 nm are 6.20 × 10−21 and 3.47 × 10−21 cm2, respectively. In brief, the above findings indicate that the Er:SrF 2 ceramics is a promising candidate as middle infra-red laser gain media. • Pure-phase Er:SrF 2 nano-powders were synthesized by the co-precipitation method. • 1 at.% Er:SrF 2 ceramics with fine grains were fabricate by two-step sintering. • Spectral properties for 1. at.% Er:SrF 2 ceramics were systemically explored. [ABSTRACT FROM AUTHOR]

Neodymium doped yttrium aluminum garnet (Nd:YAG) transparent ceramics were fabricated from Nd:YAG nanopowders synthesized via a reverse precipitation method by vacuum sintering and successive hot isostatic pressing (HIP) post-treatment. The powders obtained by calcining the precursor at 1100 °C for 4 h and then ball milling for 2 h with 0.5 wt% TEOS as sintering aid were used to fabricate Nd:YAG ceramics. The green bodies were vacuum sintered at 1500–1800 °C for 10 h, followed by the HIP at 1600 °C for 3 h in 200 MPa Ar atmosphere. Influence of the calcination temperature on the phase, morphology and particle size evolution of the nanopowders, as well as the optical transparency and microstructure of the obtained Nd:YAG ceramics before and after the HIP post-treatment was investigated in detail. It was found that for the post-treated 1800 °C-vacuum-sintered Nd:YAG ceramic sample, the in-line transmittance increased from 48.0% up to 81.2% at the lasing wavelength of 1064 nm. [ABSTRACT FROM AUTHOR]

Gd 2 O 2 S:Tb nanopowders were synthesized in hot water-bath with the equal mole ratio of Gd 2 O 3 and H 2 SO 4 as raw materials. The influence of initial bathing temperature of Gd 2 O 3 and H 2 SO 4 , which was defined as initial temperature, on the properties of precursors and powders was investigated. The precursors and Gd 2 O 2 S:Tb powders showed a layered structure, and all the reduced powders exhibit a pure Gd 2 O 2 S phase. With the increase of the initial temperature, the size and thickness of the flakes in the precursors and Gd 2 O 2 S:Tb powders increased. Using the obtained powders as starting materials, Gd 2 O 2 S:Tb scintillation ceramics were successfully fabricated by vacuum pre-sintering at 1250 °C for 3 h, followed by HIP post-treatment at 1450 °C for 3 h. The Gd 2 O 2 S:Tb ceramics from the powders prepared at lower initial temperature show a rapid densification rate during pre-sintering. The Gd 2 O 2 S:Tb ceramics from powders synthesized at 7 °C show the highest optical transmittance and XEL intensity, and the total transmittance of the ceramics with the thickness of 1.0 mm is 25.5% at 545 nm. The microstructures of the Gd 2 O 2 S:Tb ceramics from powders synthesized at different initial temperatures were also studied. • Gd 2 O 2 S:Tb powders prepared at water-bath temperature of 7 °C exhibit the thinnest flake. • Gd 2 O 2 S:Tb ceramics were fabricated by vacuum pre-sintering and HIP post-treatment. • The total transmittance of Gd 2 O 2 S:Tb ceramics from the powders prepared at 7 °C reaches 25.5% at 545 nm. [ABSTRACT FROM AUTHOR]