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Bismuth telluride-based materials are well known for their excellent thermoelectric (TE) properties within the near-room temperature range. However, the poor thermoelectric performance of their n-type counterparts has posed a major hindrance to the application of bismuth telluride-based thermoelectric generator (TEG). In this study, a dual optimization approach was implemented. Specifically, 2D ceramic nano-sized hexagonal boron nitride (h-BN) was introduced into n-type Bi 2 Te 2.7 Se 0.3 (BTS) to enhance its performance, aligning it with p-type materials. It is indicated that ceramic h-BN decoration leads to the emergence of a high density of dislocations, which boosts the phonon scattering and reduces lattice thermal conductivity significantly. Meanwhile, a high carrier mobility is maintained to ensure an improved power factor. With the addition of moderate ceramic h-BN, the composite material achieved a ZT value of 1.1 at 400 K. The geometric configuration of TEG was optimized using finite element methods to strike the optimal balance between output power (P o u t ) and efficiency (η). Based on the structure optimization results, the predicted P o u t and η increased by 48 % and 36 %, respectively. The fabricated TEG demonstrated to achieve an efficiency of 6.4 %. This work allows the evolution from bismuth telluride-based prototype to a functional TEG advanced in room-temperature heat recovery. [ABSTRACT FROM AUTHOR]

Tricalcium silicate (C 3 S) has been attested to be self-curable, bioactive and biodegradable, but its high alkalinity could inhibit cell proliferation and differentiation. By designing the preparation process, biomaterials could be adjusted to confer the desired properties. This study showed that the pH value of modified C 3 S by carbonization (signed as C–C 3 S) notably reduced from 11.2 to 8.15 with adjusting the carbonization process. Meanwhile, C–C 3 S displayed a suitable setting time (from 9.49 ± 0.19 to 11.20 ± 0.18 min). In addition, its compressive strength can reach about 10.61 MPa, which is comparable to that of cancellous bone. Carbonation time was confirmed to be a key factor in the formation of calcite by using carbon dioxide modified hydrolyzed tricalcium silicate. The results of cell activity and proliferation suggested that the C–C 3 S had improved osteogenic activity. Therefore, personalized design and customization of biomaterials can be realized by adjusting carbonization processes according to clinical requirements for bone cement. C–C 3 S may be a promising material for bone repair. [ABSTRACT FROM AUTHOR]

Er/Yb co-doped transparent glass ceramics containing nanocrystalline Bi 2 ZnB 2 O 7 were successfully prepared by a high-temperature melting method. X-ray diffraction analysis confirmed the structural properties of the crystal and glass phases of the glass ceramics. Scanning electron microscope images indicated that nanocrystalline Bi 2 ZnB 2 O 7 with an average size of 30–40 nm was uniformly distributed in the glass matrix. Infrared spectroscopy demonstrated that the glass and glass ceramics had different vibrational peaks. The absorption spectra showed the absorption peaks of the samples, and the main spectral parameters of each absorption peak were calculated using the Judd–Ofelt theory. The emission spectra of the samples showed ultra-wideband fluorescence from 1400 to 1700 nm under excitation at 980 nm, which was enhanced by precipitation of nanocrystalline Bi 2 ZnB 2 O 7 and the addition of Yb3+ ions. Our research showed that Er/Yb co-doped glass ceramics containing nanocrystalline Bi 2 ZnB 2 O 7 are a promising material for application in near-infrared optical amplifiers. [ABSTRACT FROM AUTHOR]

Abstract Bismuth magnesium niobate (Bi 3/2 MgNb 3/2 O 7 , BMN) thin films were prepared on bare SiO 2 /HR-Si and Pt/TiO 2 /SiO 2 /HR-Si substrates by using sol-gel spin coating technique followed by rapid thermal annealing process. The influence of the interface on crystalline structure and tunable dielectric properties of the two types of BMN films were investigated. It was found that the BMN films prepared on SiO 2 /Si substrate with a BMN/SiO 2 interface structure had higher orientation and better crystallinity. The deposited BMN thin films with a BMN/SiO 2 interface structure exhibited superior tunability of 52.5%, while it showed a relative small tunability value of the film with BMN/Pt interface structure. It suggests that the interface state between the films and substrates, electric field distribution, and orientation degree are responsible for the impacts on the microstructure and tunable dielectric properties of the BMN thin films. [ABSTRACT FROM AUTHOR]

Abstract A high near-infrared reflective green pigment with a low cobalt content, Zn 0.96 Co 0.04 O, was prepared by solution combustion synthesis. The pigment was characterized by XRD, SEM, TG-DSC, UV–vis and CIE L*a*b*C*h* colorimetric. The resulting green pigment showed that the chromaticity performance is better. The doping Co did not affect the main crystalline structure, all samples were retained ZnO wurtzite structure. The better green hue is a* = −15.35 and achieved a near-infrared reflectivity up to 40%, when CoO content was x = 0.04, combustion agent was glycine, calcination temperature was 1000 °C. The synthesized pigments have a better thermal stability, chemical stability and a small amount of cobalt oxide (2.8 wt%), and the preparation process is simple. Therefore, the green pigment of ZnO wurtzite structure has great potential in serving as cool pigments for building coatings. [ABSTRACT FROM AUTHOR]

Abstract In this research, the optical properties of Er3+/Yb3+ co-doped phosphate glass have been studied to explore the potential of this glass system in laser and electronic amplifiers. The Judd–Ofelt (J-O) intensity parameter (Ω t) in the J-O model was established to determine the absorption intensity of the glass. The optical properties of the glass can be evaluated by various radiation parameters such as the radiative transition probabilities (A rad), stimulated emission cross sections (σ e), branching ratios (β JJ'), maximum half-width values (Δ λ p), and the radiation lifetime (τ rad) of the glass. It was found that in the case of Yb3+ as a sensitizer, the spectral properties of the Er3+ doped glass can be maximized. The data of A rad , β JJ' , τ rad , σ e and Δ λ p obtained by Er3+/Yb3+ co-doping can find that the Er3+-doped sample undergoes 4I 13/2 –4I 15/2 transition at 1.56 µm, and the stimulated emission cross section is greatly improved. The application prospects of the glass in solid near-infrared laser and electronic communication was discussed. According to the comprehensive discussion and analysis, the glass has great application potential. [ABSTRACT FROM AUTHOR]

Ti(C, N)-based cermets were coated with TiAlN and TiAlN/CrAlN films by physical vapor deposition. The cross-sectional morphology was characterized by scanning electron microscopy (SEM), and the adhesive strength was evaluated by the scratch test. Cutting tests on the coated cermets were conducted on the different cutting conditions. The cutting performance and wear mechanism were analyzed with SEM and EDS. It is found that TiAlN coating has a better adhesion to the cermet substrate. The coated cermet inserts show better wear resistance than the uncoated ones. By contrast, the TiAlN coating suffers a slight abrasive flank wear. However, the TiAlN/CrAlN coating show more severe adhesive flank wear because of the Cr interdiffusion between the inserts and the workpiece. In addition, TiAlN coating is weak in resisting against oxidation wear, while the TiAlN/CrAlN coating has an excellent resistance to oxidation. [ABSTRACT FROM AUTHOR]