We consider a parametric Dirichlet problem driven by a nonautonomous (p, q)-differential operator with unbalanced growth. In the reaction we have the competing effects of a parametric (p-1)-superlinear term and of a (p-1)-linear perturbation. Using variational tools, we show that for all small values of the positive parameter, the problem has at least two nontrivial bounded solutions.
The aim of this study is to investigate the effects of chemically modified hexagonal boron nitride (hBN) particles on the tribological properties of polyethylene glycol (PEG) based lubricant and sedimentation in PEG. Thermally purified and chemically modified hBN particles were compared with commercially available hBN particles of various sizes. Tribological tests were performed on a ball-on-disk optical tribometer under rolling–sliding conditions using a 100Cr6 steel ball and BK7 glass disk. The effects of hBN particle size and surface modification on the frictional behavior across boundary, mixed, and elastohydrodynamic (EHL) lubrication regimes were examined. The most pronounced reduction in the friction was achieved with the largest hBN particles (≈6.6 μm), which unfortunately tend to agglomerate in liquid PEG though. It was observed that agglomeration was strongly suppressed by chemical modification of hBN´s surface. The work also includes a post-experimental analysis which demonstrated good durability of hBN particles in PEG lubricant after tests.
Hydroxyapatite (HA) is promising for bone-replacement applications, but its structural use is limited by low fracture toughness and defect-sensitive brittle failure. Here, DLP printed HA containing 1 vol% Al2O3 plate-like particles was evaluated in three build orientations. XRD showed an HA-dominated phase composition with minor β-TCP and no evidence of extensive bulk degradation. All specimens reached similar relative densities of 92–93% t.d., yet microscopy revealed pronounced local changes: the particles aligned within the printed layers, were surrounded by microporous halos, and were locally associated with MgAl2O4 and CaAl2O4 phases. The mechanical response was strongly orientation dependent. Al2O3 addition did not improve flexural strength or clearly enhance fracture toughness because potential crack-deflection mechanisms were offset by particle-associated porosity and interfacial defects. Microporous halo formation, rather than bulk densification or phase stability, was therefore identified as the main barrier to effective low-volume reinforcement of DLP printed HA.
Recently, Transformer has made significant progress in various vision tasks. To balance computation and efficiency in video tasks, recent works heavily rely on factorized or window-based self-attention. However, these approaches split spatiotemporal correlations between regions of interest in videos, limiting the models' ability to capture motion and long-range dependencies. In this paper, we argue that, similar to the human visual system, the importance of temporal and spatial information varies across different time scales, and attention is allocated sparsely over time through glance and gaze behavior. Is equal consideration of time and space crucial for success in video tasks? Motivated by this understanding, we propose a dual-path network called the Overall Glance and Refined Gaze (OG-ReG) Transformer. The Glance path extracts coarse-grained overall spatiotemporal information, while the Gaze path supplements the Glance path by providing local details. Our model achieves state-of-the-art results on the Kinetics-400, Something-Something v2, and Diving-48, demonstrating its competitive performance. The code will be available at https://github.com/linuxsino/OG-ReG.
Single crystals of cubic boron nitride (cBN) exceeding 10 mm in size were grown by the high-pressure high-temperature (HPHT) temperature-gradient method using a Ni–Cr-based solvent catalyst. Compared with the previously reported maximum crystal size of approximately 3 mm, this improvement was achieved by maintaining a stable precursor flux during one week of growth at a source temperature of 1950 °C. In contrast to diamonds, which were grown with the same HPHT cell and showed nearly isometric shapes, the cBN crystals had elongated shapes. We attribute this cBN morphology to a localized growth near the BN source due to the relatively low effective mass transport of boron and nitrogen species in the metallic solvent.
