Tetrahedral amorphous carbon (ta-C) has a relatively high hardness, and it can be used to enhance film properties such as wear resistance. However, the high hardness of ta-C can adversely affect a counterpart and accelerate its wear, and the resulting wear imbalance between the film and its counterpart can cause vibrations. This issue may be resolved by improving the wear of the counterpart. This study aimed to reduce the hardness and improve the fracture toughness of ta-C films to enhance the durability of a tribosystem, which was achieved by toughening a composite and ductile phase. A multilayered nanocrystalline (nc)-Cu/ta-C nanocomposite film was fabricated that allowed for reductions in the wear of the film and its counterpart of more than 88% and 99%, respectively.
Abstract Solid‐state luminescent carbon dot without dispersion matrices is studied to overcome aggregation‐caused quenching, but it usually shows spectral shift between solution‐ and solid‐state accompanying a dramatic decrease of fluorescence intensity, which hinders a real application. Herein, polymer carbon dot (PCD) showing solid‐state luminescence without red‐shift is synthesized by low‐temperature reaction. The PCD solution and solid have the same emission peaks at 434 nm and similar absolute quantum yields of 68.2% and 62.7%, respectively, which is uncommon feature compared to other carbon dots. The mechanism for solid‐state luminescence and emission color consistency is investigated by structural analysis of the PCD compared to carbon dot that shows red‐shift in solid‐state. The PCD is utilized into light‐emitting diode application as a phosphor, and little color change in emission without significant decrease in luminous efficacy is achieved even with high loading fraction (50 wt%), opening the possibility of real application in solid‐state lighting.
Buckling Restrained Braces (BRBs) show good seismic behavior. They do not dissipate energy, however, when they are subjected to minor earthquakes or wind. Hybrid Buckling Restrained Braces (H-BRBs), which can improve the wind performance of the BRB system, are a kind of hybrid damper system composed of a viscoelastic damper and BRBs. In this paper, two H-BRB specimens with different cores were experimentally investigated to ensure the structural behavior of the H-BRB system in an elastic range. The axial deformation of the primary resisting system was compared with that of the secondary resisting system, and the equivalent damping ratio of the H-BRBs was estimated. It was concluded that H-BRBs with double shear dampers show good structural behavior and are applicable to tall buildings, to improve the building performance at a comfortable level.
A hybrid of multi-walled carbon nanotube (MWCNT) and gold nanoparticle (Au NP) was prepared under ultrasound irradiation. The approach starts with the functionalization of the walls of MWCNTs with mercaptobenzene moieties for the subsequent immobilization of Au NPs. From the Raman spectra, mercaptobenzene was proven to exist on the MWCNTs. Gold ions were added to the aqueous dispersion of functionalized MWCNTs (f-MWCNTs), and were reduced with the aid of ultrasound and ammonium hydroxide. The reduced gold nanoparticles were examined from the TEM images. Au NPs adhered specifically on the thiol groups of mercaptobenzene to be deposited uniformly on the outer walls of the f-MWCNTs. The application of ultrasound led to a high yield of MWCNT-Au nanocomposites and to the dense distribution of the Au NPs. Moreover, the synthesis reaction rate of the hybrid was considerably enhanced relative to synthesis with mechanical agitation. Through an adsorption test using gold-binding-peptide-(GBP)-modified biomolecules, the hybrid's potential for biological diagnosis was verified.
In decision-making, choices impact the present and cascade into future decisions, highlighting the importance of confidence when making a decision. Here, we investigated the meta-network level neural correlates of this confidence by estimating the instantaneous changes in precision in selecting actions and comparing them with brain state trajectories. To confirm the relationship between behavioral and neural signals, we leveraged inter subject correlation to determine how similar the group shared components of time-series of precision-triggered meta-network occurrences are across participants and how this similarity changes during decision-making. We found that policy precision is a proper behavioral signal to explain the meta-network level neural dynamics. It positively correlated with the default mode network (DMN) dominant state, the occurrence of which is mutually exclusive with the dorsal attentional network-(DAN) and frontoparietal network (FPN)-dominant state, the activation of which is speculated to be associated with a highly uncertain state and arises from increased integration between the DAN, FPN, and DMN. Therefore, supporting the novel perspective that the DMN may reflect internal beliefs, these findings indicate that their integration promotes the DAN and FPN to exert attention to decrease uncertainty.
Assembly of DNA Nanowire Arrays In article number 2102243, So Nagashima, Myoung-Woon Moon, and co-workers introduce a bottom-up method for readily assembling DNA molecules into periodically aligned 2-nm-thin nanowires. Anisotropically superhydrophilic wrinkles are used to develop capillary bridges of DNA solution that recede unidirectionally on a hydrophobic flat surface. The molecules in each capillary bridge are then evaporatively assembled into a nanowire. The inter-nanowire separation can be tuned by controlling the wrinkle dimensions.
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