This study aimed to enhance the tribological properties of diamond-like carbon (DLC) in lubrication by depositing nickel (Ni) onto the surface layer of tetrahedral amorphous carbon (ta-C) film. Ni/ta-C of ∼0.1 μm Ni exhibited significantly lower friction than ta-C on molybdenum dithiocarbamate (MoDTC) lubrication. The ta-C served as a hard, wear-resistant base, and Ni aided tribochemistry. X-ray photoelectron spectroscopy (XPS) revealed many Mo⁴⁺ peaks attributed to MoS₂ formation in Ni/ta-C surfaces, and Auger electron spectroscopy (AES) confirmed Mo and S enrichment near the surface. Detailed analysis suggested Ni did not catalyze decomposition of MoDTC to MoS₂, but promoted oxidation of transferred Fe debris, leading to formation of an Fe oxide layer. This layer likely acted as a supporting platform for subsequent formation and stabilization of the MoS₂ layer, consistent with mechanisms previously reported for transition-metal nitride coatings. This finding indicates Ni accelerates MoS₂ formation indirectly through Fe-mediated processes, resulting in substantial friction reduction and maintaining the wear resistance of DLC.
A size- and depth-extended three-dimensional (3D) aerial display is realized by combining a light-field display with a magnifying lens and a Fresnel-lens-enhanced aerial imaging by retro-reflection (LeAIRR) system. In conventional aerial 3D displays, the sizes and depth of the 3D aerial image are limited by the physical sizes of the light-field display panel. In the proposed optical system, the magnifying lens optically enlarges the virtual light-field display plane without increasing the physical panel size, thereby enabling simultaneous scaling of the aerial-image size and depth. In addition, the LeAIRR configuration suppresses diffraction caused by the retro-reflector by introducing a Fresnel lens for resolution enhancement in the optical path. The light-field display enables a natural 3D aerial image that changes continuously with the viewer's position. To validate the different characteristics between longitudinal and lateral magnifications by use of lens in 3D images, the resulting aerial image is quantitatively evaluated. The measured magnifications are consistent with geometrical-optics predictions, and the longitudinal magnification exhibits an approximately quadratic dependence on the lateral magnification. These results indicate that the proposed optical system provides a scalable solution for overcoming panel-size limitations in 3D aerial displays and enables the application of large-scale 3D aerial interfaces.
An interconnection network is an inevitable component in a parallel computer. It offers communication capabilities in the parallel machine, affecting performance issues of parallel computation. Thus, various discussions are being made from a variety of aspects to reduce the communication cost and to improve the performance. This paper addresses the packet scheduling problem, which is a promising method for improving the performance, in the collective communication. Our preceding work has proposed a unique optimization method Lopit (lazy optimization of packet injection timing). This paper extends the method by introducing a group nature in collective communication situations and proposes a new method G-Lopit (grouped Lopit). Evaluation results in our interconnection network simulator reveal the significant effectiveness of the proposed method. The G-Lopit method outperforms the traditional GA and the preceding Lopit methods. It improves the performance of collective communication at most 1.18 times from the Lopit method in 32 & times;32 2D-torus network with bcmp traffic. In comparison with unoptimized situations, it achieves at most 1.73 times improvement in the shfl traffic.
Laser-produced tin (Sn) plasma is extensively used as an extreme ultraviolet (EUV) light source for advanced lithography; however, the collector mirror lifetime is considerably shortened by high-energy debris from the plasma. The introduction of hydrogen (H2) gas into the plasma region can mitigate debris through ion-neutral collisions and chemical reactions forming gaseous stannane (SnH4). However, the detailed Sn-H interaction mechanisms remain uninvestigated. Herein, visible emission spectroscopy was used to investigate the spatiotemporal behaviors of Sn and H plasmas generated by 12-ps, 1,064-nm laser pulses incident on a solid Sn target in a 100 Pa H2 atmosphere. Spatiotemporalresolved measurements of H alpha and H beta lines revealed prompt hydrogen excitation following plasma generation, with electron temperatures of 1-2 eV and electron densities up to 1 & times; 1017 cm-3 near the target. These conditions aid the formation of hydrogen radicals that react with Sn atoms/ions to produce SnH4, contributing to the effective mitigation of debris. These findings offer insights into the optimization of the EUV source performance and the prolongation of the optical component lifetime.
A portable microfluidic titration system using a smartphone camera was developed as a detector for onsite quantitative analysis. Two types of cross-shaped microfluidic devices with different channel geometries were designed and evaluated to improve the visual detectability of the equivalence point under limited spatial resolution. An expanding-channel device was found to promote molecular diffusion downstream, resulting in enhanced visibility of the equivalence point compared to a constant-width device. Using the optimized device, a strong acid–strong base system was subjected to acid–base titration using bromothymol blue as the indicator. The color images captured by the smartphone camera were analyzed by extracting the red channel intensity profiles and used to determine the distance corresponding to the equivalence point. A linear relationship was obtained between the measured distance and hydrochloric acid concentration in the range of 25–150 mM. The applicability of the proposed system was demonstrated by analyzing a real hot-spring water sample. The determined acid concentration was in good agreement with that obtained by conventional volumetric titration, with no statistically significant difference at the 95
