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ZnO varistor samples generally have poor preparation repeatability. In this work, ZnO varistor samples A and B with the same preparation technique showed significant differences in properties, and the reasons were explored in detail. Nonlinear coefficient (α) values of 42.59 and 72.68, and leakage current density of 0.013 mA/cm2 and 0.002 mA/cm2 were found for samples A and B, respectively, which are markedly different between the samples. However, samples A and B showed the same phases. In addition, samples A and B exhibited mean grain size (d) of 2.21 μm and 2.47 μm, double Schottky barrier height (φB) of 0.45 eV and 0.48 eV, and grain boundary resistivity (ρgb) of 5.32 × 106 Ω m and 5.40 × 106 Ω m, respectively, which were all similar between the two samples. According to the low-temperature dielectric spectral analyses, the values of k1 of samples A and B, reflecting the concentration of interstitial zinc, were 14.06 and 11.09, and the values of k2 reflecting the concentration of oxygen vacancy were 7.48 and 3.35, respectively. Therefore, the obvious difference in the electrical properties between samples A and B may be caused mainly by the obvious difference in the concentration of oxygen vacancy. Thus, this work provides evidence of the effects of oxygen vacancy on the electrical properties of ZnO varistors. [ABSTRACT FROM AUTHOR]

Cobalt (Co) as an additive has a remarkable impact on the microstructure and electrical properties of zinc oxide (ZnO) varistor ceramics. In this paper, ZnO varistor ceramics were prepared by the conventional solid-phase method, based on the base formula of ZnO-Bi2O3-Sb2O3-MnO2-Cr2O3 with Co2O3 doped and Co3O4 doped respectively, and their microstructure and electrical properties were compared. It's found that doped Co mainly affects the average grain size of ZnO varistor ceramics, and the average grain size of samples doped Co2O3 s greater than that of samples doped Co3O4. In addition, the Co3O4 doped samples has a higher nonlinear of 51. 40, a higher breakdown field of 338. 29 V/mm, a lower leakage current density of 1.33 µA/cmµ, and a higher barrier height of 0.69 eV, which has excellent comprehensive performance. Therefore, Co3O4 s better than Co2O3 to improve microstructure and electrical properties of ZnO varistor ceramic. [ABSTRACT FROM AUTHOR]

Cr3+‐doped near‐infrared (NIR) phosphors have attracted significant attention in recent years. Despite this, achieving high‐performance NIR phosphors with broadband emission and excellent thermal stability remains a considerable challenge. This study presents Lu3Ga5O12:Cr3+, which demonstrates a tunable emission peak ranging from 705 to 759 nm and an increased full‐width at half‐peak maximum (FWHM) from 46 to 139 nm by substituting the [Mg2+‐Ge4+] chemical unit for the [Ga3+‐Ga3+] unit. Additionally, in Lu3MgGa3GeO12:Cr3+, Yb3+, an energy transfer channel (Cr3+‐Yb3+) is constructed. Under blue light excitation, the characteristic emission peaks of Cr3+ (600–900 nm) and Yb3+ (900–1100 nm) are observed simultaneously. However, the emission band between 850 and 900 nm is relatively weak, resulting in a discontinuous emission spectrum. To address this, Lu3MgGa3GeO12:Cr3+, Yb3+, Nd3+ phosphors are proposed, which exhibit a continuous broadband NIR emission with a FWHM of 253 nm and internal quantum efficiency of 47.3%. The luminescence intensity retains 81% of its room temperature value even at 423 K. Combining this new phosphor with a blue LED chip results in a portable NIR light source with potential applications in non‐destructive detection, information encryption, bio‐imaging, and NIR remote control. This work offers a novel perspective for developing high‐performance NIR phosphors. [ABSTRACT FROM AUTHOR]

Background: The integrity of the lateral wall in femoral intertrochanteric fractures significantly impacts fracture stability and internal fixation. In this study, we compared the outcomes of treating intertrochanteric fractures with lateral wall involvement using the ortho-bridge system (OBS) combined with proximal femoral nail antirotation (PFNA) versus simple PFNA from a biomechanical perspective., Methods: Finite-element models of femoral intertrochanteric fractures with lateral wall involvement were subjected to fixation with OBS combined with PFNA and simple PFNA. Von Mises stress measurements and corresponding displacement assessments for each component of the model, including the proximal femur and lateral wall, were used to evaluate the biomechanical effects of OBS fixation on bone and intramedullary nail stability., Results: Using PFNA alone to fix intertrochanteric fractures with lateral wall involvement resulted in von Mises stress levels on the lateral wall exceeding safe stress tolerances for bone growth. OBS fixation significantly reduced stress on the lateral wall of the femur and minimized the stress on each part of the intramedullary nail, reducing the overall displacement., Conclusion: In cases of intertrochanteric fractures with lateral wall involvement, PFNA fixation alone may compromise the biomechanical integrity of the lateral femoral wall, increasing the risk of postoperative complications. The addition of OBS to PFNA significantly reduces stress on the lateral femoral wall. Consequently, OBS should be considered for lateral wall fixation when managing intertrochanteric fractures combined with lateral wall fractures., Competing Interests: Authors NL and ZH were employed by Tianjin Walkman Biomaterial Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Long, Liu, Huang, Liang, Liu, Huang, Zhang and Wang.)

Background: To compare the biomechanical parameters of AO/OTA type A3 distal femoral fractures fixed bilaterally with a bridge combined fixation system (BCFS) and lateral locking compression plate + locking reconstruction plate (LCP + LRP)., Methods: Twelve A3 distal femoral fracture models with medial cortical defects of the distal femur were created using synthetic femoral Sawbones. BCFS and LCP + LRP were used for bilateral fixation, with six in each group. Axial compression and torsion tests were performed on the two groups of fracture models to determine their stiffness during axial compression and the Torsional stiffness during torsion tests. Axial compression failure tests were performed to collect the vertical loads of the ultimate failure tests., Results: In the test conducted on the fixed type A3 distal femoral fracture models, the axial stiffness in the BCFS group (group A) (1,072.61 ± 113.5 N/mm) was not significantly different from that in the LCP + LRP group (group B) (1,184.13 ± 110.24 N/mm) (t = 1.726, P = 0.115), the Torsional stiffness in group A (3.73 ± 0.12 N.m/deg) was higher than that in group B (3.37 ± 0.04 N.m/deg) ( t  = 6.825, P  < 0.001),and the ultimate failure test of type A3 fracture model showed that the vertical load to destroy group A fixation (5,290.45 ± 109.63 N) was higher than that for group B (3,978.43 ± 17.1 N) ( t  = 23.28, P  < 0.05). Notably, intertrochanteric fractures occurred in groups A and B., Conclusions: In the fixation of type A3 distal femoral fractures, the anti-axial compression of the BCFS group was similar to that of the LCP + LRP group, but the anti-torsion was better., Competing Interests: ZH was employed by Tianjin Walkman Biomaterial Co., Ltd. Newton Laboratory. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Liu, Huang, Qi, Long, Zhang, Liu, Zuo and Wang.)