Accurate and fast localization of EBSD pattern centers for screen moving technology.

The authors of this study develop an accurate and fast method for the localization of the pattern centers (PCs) in the electron backscatter diffraction (EBSD) technique by using the model of deformation of screen moving technology. The proposed algorithm is divided into two steps: (a) Approximation: We use collinear feature points to obtain the initial value of the coordinates of the PC and the zoom factor. (b) Subdivision: We then construct a deformation function containing the three parameters to be solved, select a large region for global registration, use the inverse compositional Gauss-Newton (ICGN) to optimize the objective function, and obtain the results of iteration of the PC and the zoom factor. The proposed algorithm was applied to simulated patterns, and yielded an accuracy of measurement of the PCs that was better than 4.6×10-6 of their resolution while taking only 0.2 s for computations. Moreover, the proposed algorithm has a large radius of convergence that makes it robust to the initial estimate. We also discuss the influence of factors of mechanical instability on its results of calibration during the insertion of the detector, and show that errors in measurements caused by the tilt motion of the camera are related only to the tilt angle of its motion and the detector distance, and are unrelated to the distance moved by it.

Highly potent Platinum(IV) complexes with multiple-bond ligands targeting mitochondria to overcome cisplatin resistance.

The efficacy and resistance of cisplatin-based compounds are very intractable problems at present. This study reports a series of platinum(IV) compounds containing multiple-bond ligands, which exhibited better tumor cell inhibitory activity and antiproliferative and anti-metastasis activities than cisplatin. The meta-substituted compounds 2 and 5 were particularly excellent. Further research showed that compounds 2 and 5 possessed appropriate reduction potential and performed significantly better than cisplatin in cellular uptake, reactive oxygen species response, the up-regulation of apoptosis and DNA lesion-related genes, and drug-resistant cell activity. The title compounds exhibited better antitumor potential and fewer side effects than cisplatin in vivo. Multiple-bond ligands were introduced into cisplatin to form the title compounds in this study, which not only enhanced their absorption and overcame drug resistance but also demonstrated the potential to target mitochondria and inhibit the detoxification of tumor cells.

Measurement of the pattern shifts for HR-EBSD with larger lattice rotations.

High-resolution electron backscattering diffraction (HR-EBSD) was used to measure rotations and elastic strains by matching diffraction patterns based on cross-correlation. However, the subset-based phase correlation algorithm was unable to determine pattern shifts accurately when large rotations occurred. In this paper, a new matching algorithm was proposed to measure pattern shifts and recover the elastic strain and lattice rotation with finite deformation theory. The algorithm was implemented in two steps: (a) Integral pixel matching: The pixel-related information of the Kikuchi patterns was mapped to the original three-dimensional sphere to obtain the image projected in parallel by using the feature points as the pattern center through the transformation of its spatial coordinates. The correlation between the images projected in parallel before and after deformation was then obtained. The locations of the integral pixels were determined by the peaks of the surface of correlation obtained by traversing all pixels in the search area. (b) subpixel refinement: the locations of subpixels were obtained by FAGN with an appropriate shape function involving rotation and translation. The algorithm was applied to dynamic simulated test sets, and its results were compared with those of the first-pass cross-correlation and the second-pass cross-correlation method with remapping. The proposed method was more robust in the case of rotation and solved the problem that displacement vectors could not be accurately measured when a larger lattice rotation occurred. The mean errors of the measured displacement, rotation, and strain components were 0.02 pixel, 0.5×10-4rad, and 1×10-4, respectively. Compared with the second-pass cross-correlation method, the angle of rotation was more precisely extracted.

Sulfur-Doped rGO Aerogel Enables the Anchoring of 1T/2H MoS2 for Durable Oxygen Reduction Reaction Catalyst Support.

Durability is crucial for the long-term application of cathode oxygen reduction reaction (ORR) catalysts in fuel cells. In this work, sulfur was successfully doped into reduced graphene oxide (rGO) aerogels to achieve the formation of 1T/2H hybrid phase MoS2 , obtaining MoS2 @S-rGO-300 composite ORR catalyst support. After loading ultrafine Pt nanoparticles, Pt/MoS2 @S-rGO-300 showed not only an enhanced ORR activity, but also a significantly improved stability after 10000 cycles. The mass activity retention for Pt/MoS2 @S-rGO-300 after cycles reached 89.94 %, while that of Pt/rGO was only 37.44 %. Density functional theory calculations revealed that the enlarged binding energy between Pt atoms and MoS2 @S-rGO-300 led to the prevention of Pt agglomeration as well as Ostwald ripening.

Anhydrous proton conductivity of electrospun phosphoric acid-doped PVP-PVDF nanofibers and composite membranes containing MOF fillers.

A high-temperature proton exchange membrane was fabricated based on polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) blend polymer nanofibers. Using electrospinning method, abundant small ionic clusters can be formed and agglomerated on membrane surface, which would facilitate the proton conductivity. To further enhance the conductivity, phosphoric acid (PA) retention as well as mechanical strength, sulfamic acid (SA)-doped metal-organic framework MIL-101 was incorporated into PVP-PVDF blend nanofiber membranes. As a result, the anhydrous proton conductivity of the composite SA/MIL101@PVP-PVDF membrane reached 0.237 S cm-1 at 160 °C at a moderate acid doping level (ADL) of 12.7. The construction of long-range conducting network by electrospinning method combined with hot-pressing and the synergistic effect between PVP-PVDF, SA/MIL-101 and PA all contribute to the proton conducting behaviors of this composite membrane.

Effect of Additive Ti3SiC2 Content on the Mechanical Properties of B4C-TiB2 Composites Ceramics Sintered by Spark Plasma Sintering.

B4C-TiB2 composite ceramics with ultra-high fracture toughness were successfully prepared via spark plasma sintering (SPS) at 1900 °C using B4C and Ti3SiC2 as raw materials. The results showed that compared with pure B4C ceramics sintered by SPS, the hardness of B4C-TiB2 composite ceramics was decreased, but the flexural strength and fracture toughness were significantly improved; the fracture toughness especially was greatly improved. When the content of Ti3SiC2 was 30 vol.%, the B4C-TiB2 composite ceramic had the best comprehensive mechanical properties: hardness, bending strength and fracture toughness were 27.28 GPa, 405.11 MPa and 18.94 MPa·m1/2, respectively. The fracture mode of the B4C-TiB2 composite ceramics was a mixture of transgranular fracture and intergranular fracture. Two main reasons for the ultra-high fracture toughness were the existence of lamellar graphite at the grain boundary, and the formation of a three-dimensional interpenetrating network covering the whole composite.

Preparation and characterisation of poly p-phenylene-2,6-benzobisoxazole fibre-reinforced resin matrix composite for endodontic post material: a preliminary study.

OBJECTIVES: Currently used fibre-reinforced composite (FRC) intracanal posts possess low flexural strength which usually causes post fracture when restoring teeth with extensive loss. To improve the flexural strength of FRC, we aimed to apply a high-performance fibre, poly p-phenylene-2, 6-benzobisoxazole (PBO), to FRCs to develop a new intracanal post material. METHODS: To improve the interfacial adhesion strength, the PBO fibre was treated with coupling agent (Z-6040), argon plasma, or a combination of above two methods. The effects of the surface modifications on PBO fibre were characterised by determining the single fibre tensile strength and interfacial shear strength (IFSS). The mechanical properties of PBO FRCs were characterised by flexural strength and flexural modulus. The cytotoxicity of PBO FRC was evaluated by the MTT assay. RESULTS: Fibres treated with a combination of Z-6040 and argon plasma possessed a significantly higher IFSS than untreated fibres. Fibre treated with the combination of Z-6040-argon-plasma FRC had the best flexural strength (531.51 ± 26.43MPa) among all treated fibre FRCs and had sufficient flexural strength and appropriate flexural moduli to be used as intracanal post material. Furthermore, an in vitro cytotoxicity assay confirmed that PBO FRCs possessed an acceptable level of cytotoxicity. CONCLUSIONS: In summary, our study verified the feasibility of using PBO FRC composites as new intracanal post material. Although the mechanical property of PBO FRC still has room for improvement, our study provides a new avenue for intracanal post material development in the future. CLINICAL SIGNIFICANCE: To our knowledge, this is the first study to verify the feasibility of using PBO FRC composites as new intracanal post material. Our study provided a new option for intracanal post material development.