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Nickel-based superalloys have been widely used in the aerospace, petrochemical, and marine fields and others because of their good oxidation resistance, corrosion resistance, stability, and reliability at various temperatures. However, as a nickel-based superalloy is a kind of processed material, in the cutting process a large amount of cutting heat is generated due to the interaction between the tool and the workpiece. At the same time, the low thermal conductivity of the workpiece causes a large amount of cutting heat to accumulate at the contact point, resulting in serious tool wear, reduced tool life, frequent tool changes, and other problems, which increase the production cost of the enterprise. This paper introduces the tool wear mechanisms (abrasive wear, adhesive wear, plastic deformation, chemical wear, etc.) in the machining process of nickel-based superalloys and summarizes the research status of failure mechanisms, tool wear optimization, etc. Based on a review of the existing research, it was found that the purpose of adding tool coatings, optimizing tool materials and cutting parameters, or improving the cutting environment is to control the heat during the processing of nickel-based superalloys to improve the tool environment and prolong the service life. The development prospects of tool wear prevention measures in the field of nickel-based alloy machining are also described.

Powder metallurgy (PM) is a manufacturing technique that employs metal powder as the raw material, which is then molded and sintered to produce various products. PM green compacts are inherently weak, rendering them prone to damage during machining due to cutting forces, which also affect the quality of the machined surface. To study the impact of different machining variables on cutting force, a finite element simulation (FEM) was employed, focusing on cutting thickness, cutting speed, tool rake angle, and rounded edge radius. The results indicated that cutting thickness had a highly significant impact on cutting force, while the rounded-edge radius and cutting speed were also significant factors. The tool rake angle was found to have minimal effects. The optimal parameters for minimizing cutting force were identified: a cutting thickness of 0.20 mm, a cutting speed of 120 m/min, a tool rake angle of 0°, and a rounded-edge radius of 40 μm, which reduced the cutting force to 887.95 N.

Graphite is extensively used in the engineering field due to its unique properties, and the study of its cutting mechanism has become particularly important. However, the brittle fracture mechanism of graphite makes it rather easy for cracks with a unique pattern of initiation and growth to develop when processing. Herein, the ABAQUS was selected to establish a finite element model (FEM) of the graphite cutting process. The internal crystal structure of graphite was modelled by a Voronoi structure, and a cohesion unit was globally embedded into the solid unit to simulate crack initiation and growth. In addition, the complete process of chip formation and removal was demonstrated. The analysis of the simulation results showed that the graphite material underwent three periodic cycles of material removal during the cutting process, i.e., large, tiny, and small removal stages. Meanwhile, the simulation results indicated that when ac was large enough, the crack gradually grew inside the graphite and then turned to the upper surface of the graphite. However, when ac was tiny enough, the cracks hardly expanded towards the inside of the graphite but grew upwards for a short period. Then, orthogonal cutting experiments of graphite were conducted, and the FEM was verified based on the experimental chip morphology, machined surface morphology, and current geometric model of the graphite cutting process. The simulation and experimental results were consistent. The hereby-presented FEM was a complement to simulations of the processing of brittle materials.

BK7 glass, with its outstanding mechanical strength and optical performance, plays a crucial role in many cutting-edge technological fields and has become an indispensable and important material. These fields have extremely high requirements for the surface quality of BK7 glass, and any small defects or losses may affect its optical performance and stability. However, as a hard and brittle material, the processing of BK7 glass is extremely challenging, requiring precise control of machining parameters to avoid material fracture or excessive defects. Therefore, how to obtain the required surface quality with lower cost machining techniques has always been the focus of researchers. This article introduces the properties, application background, machining methods, material removal mechanism, and surface and subsurface damage of optical glass BK7 material. Finally, scientific predictions and prospects are made for future development trends and directions for improvement of BK7 glass machining.

Graphite/polymer composites are brittle materials, and tool wear, which has a significant impact on the quality of the machined surface of the material, is very serious during the cutting process. In general, the magnitude of the cutting force directly affects the tool wear; the larger the cutting force, the more severe the tool wear, which in turn affects the machined surface quality of graphite/polymer composites. Therefore, in this study, the effects of machining parameters on cutting forces during orthogonal cutting of graphite/polymer composites were investigated using single-factor and multifactor experiments with cutting speed, cutting thickness, tool rake angle, and rounded edge radius as influencing factors, and the parameters were optimized. The obtained results showed that reducing the cutting thickness and increasing the tool rake angle would significantly reduce the cutting force. During the orthogonal cutting process, when the tool had a small edge radius, the cutting force along the cutting direction was significantly larger than the cutting force along the vertical direction, and as the rounded edge radius increased, the cutting force in the vertical direction exceeded the cutting force in the cutting direction. Finally, the significance of the effect of different machining parameters on the cutting forces was analyzed using analysis of variance (ANOVA). The obtained results showed that the cutting speed, cutting thickness, tool rake angle, and rounded edge radius were extremely significant for the cutting forces along the cutting direction as well as in the vertical direction during orthogonal cutting of graphite/polymer composites.

Efficient wide-bandgap perovskite solar cells (PSCs) enable high-efficiency tandem photovoltaics when combined with crystalline silicon and other low-bandgap absorbers. However, wide-bandgap PSCs today exhibit performance far inferior to that of sub-1.6-eV bandgap PSCs due to their tendency to form a high density of deep traps. Here, we show that healing the deep traps in wide-bandgap perovskites—in effect, increasing the defect tolerance via cation engineering—enables further performance improvements in PSCs. We achieve a stabilized power conversion efficiency of 20.7% for 1.65-eV bandgap PSCs by incorporating dipolar cations, with a high open-circuit voltage of 1.22 V and a fill factor exceeding 80%. We also obtain a stabilized efficiency of 19.1% for 1.74-eV bandgap PSCs with a high open-circuit voltage of 1.25 V. From density functional theory calculations, we find that the presence and reorientation of the dipolar cation in mixed cation–halide perovskites heals the defects that introduce deep trap states. The performance of wide-bandgap perovskite photovoltaics is limited by the undesired phase transition and high density of deep level traps. Here, Tan et al. incorporate dipolar methylammonium cation to make the material defect-tolerant and achieve a high power conversion efficiency of 20.7%.

Yam (Dioscorea spp.) provides various nutritional and medicinal benefits, including a high starch content, dietary fiber, essential micronutrients, and bioactive compounds. The molecular mechanisms underlying tuber expansion have not yet been clarified. Rapid alkalinization factor (RALF) genes, which mediate various processes in plants, are thought to contribute to the regulation of tuber growth; however, their role in yam development, especially in gibberellin (GA)-mediated processes, remains unclear. Here, we characterized seven DrRALF genes in the yam genome. Analysis of gene duplication demonstrated that the expansion of DrRALF genes was primarily driven by whole-genome duplication or segmental duplication. Phylogenetic analysis revealed that DrRALF genes were concentrated in specific clusters, indicating that their functions are relatively conserved. DrRALF5 was specifically expressed in the roots, and DrRALF2, DrRALF3, DrRALF4, and DrRALF6 were highly expressed in flowers. DrRALF1, DrRALF2, DrRALF3, DrRALF4, DrRALF5, and DrRALF6 were shown to play a role in tuber expansion. Subsequent qRT-PCR validation of four selected DrRALF genes confirmed the regulation of DrRALF2, DrRALF4, DrRALF5, and DrRALF6 by GA and PP333 (paclobutrazol, a GA biosynthesis inhibitor). Yeast one-hybrid assays further showed that the DrRALF6 promoter region interacted with the GA-signaling protein, DrDELLA1. Our findings provide novel insights into the regulatory network controlling yam tuber expansion, especially through the interaction between DrRALF6 and GA signaling pathways. Our results clarify the molecular mechanisms involved in tuber growth and propose a promising strategy for improving yam production through genetic manipulation of the GA-RALF signaling pathway.

Background Rapid alkalinization factors (RALFs) are small peptides hormones that regulate plant growth and stress responses. Although RALFs have been identified in a broad range of land plant species, their roles in peanuts ( Arachis hypogaea L.) remain largely unexplored. Result A total of 24 AhRALF genes we identified in the peanut genome and classified them into three clades through phylogenetic analysis. Whole genome duplication (WGD) or segmental duplication primarily drives the expansion of AhRALFs . Gene transcription analysis revealed that two genes from clade II ( AhRALF1 and AhRALF12 ) and three from clade III ( AhRALF8 , AhRALF10 , and AhRALF21 ) are highly expressed across 18 different tissues. Notably, AhRALF11 and AhRALF24 , paralogous genes from clade II, are specifically expressed in immature buds and flowers. Additionally, AhRALF1 , AhRALF12 , AhRALF8 , and AhRALF21 exhibited elevated expression under aluminum (Al) stress. Functional analysis of AhRALF1 confirmed its secretory function and inhibitory effect on root growth in Arabidopsis . Moreover, AhRALF1 -silenced plants displayed reduced tolerance to Al stress, with altered antioxidant enzyme activities and increased oxidative damage. Conclusion This study provides a comprehensive analysis of the AhRALF gene family in peanut, highlighting their roles in growth regulation and stress responses. The function of AhRALF1 in enhancing peanut tolerance to Al stress was preliminary revealed. Our findings provide valuable insights into the roles of AhRALFs in peanuts and lay the groundwork for future functional studies and breeding programs.

As crystalline silicon solar cells approach in efficiency their theoretical limit, strategies are being developed to achieve efficient infrared energy harvesting to augment silicon using solar photons from beyond its 1100 nm absorption edge. Herein we report a strategy that uses multi-bandgap lead sulfide colloidal quantum dot (CQD) ensembles to maximize short-circuit current and open-circuit voltage simultaneously. We engineer the density of states to achieve simultaneously a large quasi-Fermi level splitting and a tailored optical response that matches the infrared solar spectrum. We shape the density of states by selectively introducing larger-bandgap CQDs within a smaller-bandgap CQD population, achieving a 40 meV increase in open-circuit voltage. The near-unity internal quantum efficiency in the optimized multi-bandgap CQD ensemble yielded a maximized photocurrent of 3.7 ± 0.2 mA cm −2 . This provides a record for silicon-filtered power conversion efficiency equal to one power point, a 25% (relative) improvement compared to the best previously-reported results. Efficient harvest of solar energy beyond the silicon absorption edge of 1100 nm by semiconductor solar cells remains a challenge. Here Sun et al. mix high multi-bandgap lead sulfide colloidal quantum dot ensembles to further increase both short circuit current and open circuit voltage.

Background: Thyroid hormones are known to regulate bone metabolism and may influence bone mineral density (BMD), as well as the risk of osteoporosis (OP) and fractures in patients with type 2 diabetes mellitus (T2DM). Recently, sensitivity to thyroid hormone indices has been linked with T2DM and OP independently. However, the relationship between thyroid hormone sensitivity and OP in euthyroid T2DM patients has yet to be investigated. Objectives: The aim of this study was to determine the association between sensitivity to thyroid hormone indices and the risk of OP in euthyroid patients with T2DM. Design: This study employed a retrospective, cross-sectional design and utilized data acquired from the Cangzhou Central Hospital in China between 2019 and 2020. Methods: We retrospectively analyzed the data of 433 patients with T2DM for anthropometric measurements, clinical laboratory test results, and BMD. The thyroid-stimulating hormone index, thyrotroph thyroxine resistance index, and thyroid feedback quantile-based index (TFQI) were calculated to determine thyroid hormone sensitivity. Finally, multivariable logistic regression, generalized additive models, and subgroup analysis were performed to detect the association between sensitivity to thyroid hormone indices and the risk of OP in these patients. Results: We did not observe a statistically significant linear relationship between sensitivity to thyroid hormones indices and OP after covariate adjustment. However, a nonlinear relationship existed between TFQI and the prevalence of OP. The inflection point of the TFQI was at −0.29. The effect sizes (odds ratio) on the left and right of the inflection point were 0.07 [95% confidence interval (CI): 0.01–0.71; p = 0.024] and 2.78 (95% CI: 1.02–7.58; p = 0.046), respectively. This trend was consistent in older female patients with higher body mass index (BMI; 25–30 kg/m2). Conclusion: An approximate U-shaped relationship was observed between sensitivity to thyroid hormone indices and OP risk in euthyroid patients with T2DM with variations in sex, age, and BMI. These findings provide a new perspective to elucidate the role of thyroid hormones in OP, specifically in patients with T2DM.