We determine the image force on an edge dislocation near a smooth closed cavity by combining traction-free boundary collocation with a displacement-circulation condition that selects the Volterra-cut sector. A circular-cavity benchmark reproduces independent analytical glide-force expressions for both bulk approach and release from the cavity: the largest absolute difference in normalized force at four tested positions in each sector is 3.3×10−6. For an equal-area family of rounded-square cavities, changing the corner-radius ratio from 0.05 to 0.35 gives median symmetric differences of 2.1% and 10.1% in the approach force along side- and corner-directed paths. The two cut sectors exert different forces at the same nominal cavity shape, dislocation position, and Burgers vector; the cavity-connected sector is more attractive in the cases examined. The same solution supplies direction-dependent continuum release thresholds under remote shear. A cutoff sweep from s0/R=0.10 to 0.20 preserves the opposing shape trends for the two paths while changing the threshold magnitudes. These results provide a benchmarked outer elastic force law and identify how cavity shape and cut connectivity enter reduced dislocation models.
Inflorescence trimming is essential for producing high-quality table grapes, but it is labor-intensive and demands skilled labor. Automating it is difficult: grape inflorescences have a complex branching structure, are frequently occluded, and are viewed under highly variable illumination, and the cutting tool must be positioned precisely. This study presents perception and motion control methods for a grape inflorescence trimming robot. The methods localize the cutting point on the inflorescence and position the cutting tool at that point, using a dual-range framework. At far range, a detection model identifies the target inflorescence and guides the manipulator to a suitable observation distance; at close range, a segmentation-based method localizes the cutting point on the main stem. This study covers cutting-point localization and tool positioning only. The robot stopped when the scissors reached the cutting point; the stem was not cut, so the trimming result itself was not evaluated. To improve perception robustness, multi-frame detection and real-time illumination augmentation were introduced. Two motion control strategies were developed and compared: sequential trajectory control (STC) and hybrid feedback control (HFC), the latter using real-time visual feedback for continuous motion correction. The system was evaluated in a greenhouse vineyard on 30 preselected inflorescences of the table grape cultivar Shine Muscat grown under a pergola training system. The mobile platform was positioned manually in front of each target. Each inflorescence was processed once by each control strategy, yielding 60 trials in total. Positioning was counted as successful when the main stem was between the scissor blades and within the effective cutting range. STC achieved a positioning success rate of 90.0 %, a mean positional error of 2.1 cm, and a mean operation time of 31.9 s. HFC achieved a positioning success rate of 83.3 %, a smaller mean positional error of 1.4 cm, and a longer mean operation time of 35.4 s. In successful trials, HFC placed the scissors where a cut would keep exactly the two uppermost lateral branches in 52.0 % of cases, compared with 33.3 % for STC. Visual feedback therefore reduced positioning error but did not increase positioning success or shorten operation time. Real-time illumination augmentation raised the target detection rate from 41.6 % to 100.0 % across 125 frames covering cloudy and sunny conditions at multiple locations in the vineyard, and multi-frame aggregation eliminated the 3.0 % single-frame target selection error. Perception took 58.5 % of the total operation time under STC and was the main time bottleneck. These results show that the proposed methods can localize the cutting point and position the cutting tool on a single cultivar in a greenhouse vineyard under natural illumination and occlusion.
The high cost and limited durability of platinum-based electrocatalysts constrain the widespread utilization of fuel cells as renewable energy systems. We demonstrate here an ambient atmosphere, semi-closed pyrolysis strategy for the preparation of an iron oxide-graphitic carbon nitride hybrid anchored on reduced graphene oxide (FexOy-g-C3N4@rGO). Unlike conventional synthesis routes that require inert-gas infrastructure, our approach streamlines the process and lowers operational costs without compromising electrocatalytic performance. The composite, prepared by heating graphene oxide, urea, and FeCl3 & centerdot;6H(2)O at 400 degrees C, demonstrates enhanced oxygen reduction reaction (ORR) activity compared to g-C3N4@rGO, achieving onset and half-wave potentials of -0.145 and -0.318 V (vs. Ag/AgCl), respectively, with an apparent electron transfer number of n = 3.43, indicating a mixed pathway with a strong 4 e(-) contribution. Although its activity is slightly lower than that of commercial Pt/C (loading: 386 vs. 849 & micro;g cm(-2) for FexOy-g-C3N4@rGO), the catalyst exhibits superior operational stability. This work not only validates the efficacy of semi-closed pyrolysis for scalable and sustainable electrocatalyst production but also advances the design of nonprecious metal-based catalysts for energy conversion, furthering the findings of our earlier investigations.
Achieving both high performance and durability is critical for polymer electrolyte fuel cells (PEMFCs). Mesoporous carbon (MPC) catalysts have attracted significant attention as promising materials for high-efficiency systems due to their high activity. In this study, we evaluated the durability of MPC catalysts under realistic startup/shutdown (SU/SD) conditions involving power generation and air confinement. Comprehensive analyses, including time-resolved monitoring of CO2 evolution and Pt dissolution, revealed that the MPC catalyst is susceptible to severe performance degradation. We found that MPC undergoes carbon corrosion driven by SU/SD conditions, particularly in regions with limited proton access, resulting not only in mass transport issues but also in severe Pt particle growth. Furthermore, we demonstrated that controlling the upper potential limit via power generation effectively mitigates this degradation by suppressing Pt oxidation and accelerating oxygen consumption, which mitigates the carbon corrosion. This study identifies critical concerns regarding the long-term operation of MPC catalysts and provides a practical strategy for suppressing degradation in real-world environments.
Aims Diffuse large B-cell lymphoma/high-grade B-cell lymphoma (DLBCL/HGBCL) with MYC and BCL2 rearrangements (double-hit lymphoma with BCL2, DHL-BCL2) is a mature aggressive B-cell lymphoma that also includes concurrent triple hit with BCL6 translocation (TH). DHL with MYC and BCL6 (DH-BCL6) can also occur. The differences among these three DLBCL/HGBCL subtypes have not yet been definitively determined.Methods and Results This study characterized the clinicopathological features and transcriptomic profiles of a series of 101 cases of DLBCL/HGBCL that were subclassified according to MYC, BCL2 and BCL6 FISH data, including cell-of-origin (COO)-like, molecular high-grade (MHG)-like and double-hit/dark-zone (DHIT/DZsig)-like signatures. DLBCL/HGBCL-DH-BCL2 was characterized by higher HGBCL morphology, CD10 positivity, GCB Hans's, GCB COO and MHG molecular subtype. DLBCL/HGBCL-TH had higher LDH levels and worse overall survival. DLBCL/HGBCL-DH-BCL6 had higher MUM1 expression, non-GCB Hans', ABC/Unclassified COO, non-MHG and low DHIT/DZ signatures. Transcriptomic analysis showed that DLBCL/HGBCL-DH-BCL2 and DLBCL/HGBCL-TH were close but separated from DLBCL/HGBCL-DH-BCL6. Gene set enrichment analysis (GSEA) revealed different levels of enrichment between the subtypes.Conclusions DLBCL/HGBCL-DH-BCL6 differs from the DLBCL/HGBCL-DH-BCL2, and the DLBCL/HGBCL-TH is associated with the worst survival. Analysis of all three genes of MYC, BCL2 and BCL6 is recommended in the context of DLBCL/HGBCL diagnosis.
