Science Daily December 21, 2022 Researchers in Japan developed a cheap and simple process to create nanoscale structures on the surface of galvanized steel, which is commonly used in the automotive industry, that provided a more conducive interface for attaching injection-molded polymers. They used hot water treatment (HWT) to produce a nanoscale needle-like structure on the zinc coating surface to enhance the joining strength and obtained strong joints of galvanized high-strength steel (GHSS) and polybutylene terephthalate (PBT) with minimal damage to the zinc coating. The effects of HWT conditions on the tensile shear strength were evaluated and the optimized strength […]
Tag Archives: S&T Japan
Designing self-assembling ‘smart materials’
Science Daily December 12, 2022 The role of hydrodynamic interactions (HIs) play in the self-organization of colloidal suspensions and biological solutions has remained elusive particularly for charged soft matter systems. Researchers in Japan studied the role of HIs in the self-assembly of oppositely charged colloidal particles, which is a promising candidate for electrical tunable soft materials. In many-body HIs and the coupling between the colloid, ion, and fluid motions they found that, under a constant electric field, oppositely charged colloidal particles formed clusters and percolated into a gel network. They revealed that the cluster-forming tendency originates from the incompressibility-induced “inverse […]
High-performance and compact vibration energy harvester created for self-charging wearable devices
Science Daily November 29, 2022 Vibration energy harvesters suffer from a significant drop in performance for non-steady-state vibrations, which are important for practical applications. Researchers in Japan demonstrated that the output power under an impulsive force can be increased significantly by placing a U-shaped metal component, called a dynamic magnifier (DM), under a MEMS piezoelectric vibration energy harvester (MEMS-pVEH) with a Pb(Zr,Ti)O3 film. Based on the results of numerical calculations they designed DM to have the same resonant frequency as the MEMS-pVEH and a high mechanical quality factor (). They measured the waveforms of the output voltage of the fabricated […]
Monitoring ‘frothy’ magma gases could help evade disaster
Phys.org November 21, 2022 Researchers in Japan repeatedly measured isotopic compositions of noble gases and CO2 in volcanic gases sampled at six fumaroles around the Kusatsu-Shirane volcano (Japan) between 2014 and 2021 to detect variations reflecting recent volcanic activity. The synchronous increases in 3He/4He at some fumaroles suggested an increase in magmatic gas supply since 2018. The increase in magmatic gas supply was also supported by the temporal variations in 3He/CO2 ratios and carbon isotopic ratios of CO2. The 3He/40Ar* ratios showed significant increases in the period of high 3He/4He ratios. The temporal variation in 3He/40Ar* ratios may reflect changes […]
Novel nanowire fabrication technique paves way for next generation spintronics
Nanowerk November 9, 2022 Eliminating the etching process by directly fabricating nanowires onto the silicon substrate would lead to a marked improvement in the fabrication of spintronic devices. However, when directly fabricated nanowires are subjected to annealing, they tend to transform into droplets as a result of the internal stresses in the wire. Researchers in Japan have developed a new fabrication process to make L10-ordered CoPt nanowires on silicon/silicon dioxide (Si/SiO2) substrates. They coated a Si/SiO2 substrate with a material called a ‘resist’ and subjected it to electron beam lithography and evaporation to create a stencil for the nanowires, deposited […]
Researchers design next-generation electrolytes for lithium batteries
Nanowerk October 29, 2022 The lithium-metal batteries cycling encounters a low Coulombic efficiency (CE) due to the unceasing electrolyte decomposition. Improving the stability of solid electrolyte interphase (SEI) suppresses the decomposition and increases CE. However, SEI morphology and chemistry alone cannot account for CE, and a full explanation is still lacking. Researchers in Japan found that in diverse electrolytes, the large shift in the Li electrode potential and its association with the Li+ coordination structure influences the CE. Machine learning regression analysis and vibrational spectroscopy revealed that the formation of ion pairs is essential for upshifting the Li electrode potential, […]
Advanced fabric that can cool a wearer down and warm them up
Nanowerk October 11, 2022 Textiles incorporated with phase changing materials (PCMs) can bridge the supply and demand for energy by absorbing and releasing latent heat. The integration of solar heating and the Joule heating function supplies multidriving resources, facilitates energy charging and storage, and expands the service time and application scenarios. Researchers in Japan have developed a fibrous membrane-based textile by designing the hierarchical core–sheath fiber structure for trimode thermal management. Coaxial electrospinning allows an effective encapsulation of PCMs, with high heat enthalpy density enabling the membrane to buffer drastic temperature changes in the clothing microclimate. The favorable photothermal conversion […]
New nanocomposite films boost heat dissipation in thin electronics
Phys.org September 26, 2022 Thermally conductive films with large in-plane anisotropy to prevent thermal interference between heat sources in close proximity and to cool in other directions by diffusion are important for efficient heat dissipation of thin electronic devices. Researchers in Japan have developed flexible composite films composed of a uniaxially aligned carbon-fiber filler within a cellulose nanofiber matrix through liquid-phase three-dimensional patterning. The film exhibited a high in-plane thermal conductivity anisotropy of 433%, with combined properties of a thermal conductivity of 7.8 W/mK in the aligned direction and a thermal conductivity of 1.8 W/mK in the in-plane orthogonal direction. […]
A little strain goes a long way in reducing fuel cell performance
Science Daily September 9, 2022 Using a proton-conducting oxide as an electrolyte film in electrochemical devices introduces an interface, which thermally and chemically generates mechanical strain. To reduce the strain researchers in Japan focused on BZY20, which is a combination of yttrium, barium, zirconium, and oxygen atoms. They found that the atoms on the edges of this cube are 2% closer at the interface between the oxide and the surface than in layers far away from the surface. This compressive strain reduces the proton conductivity to nearly 1/100,000 of what it is in bulk samples. As the layers build up, […]
From bits to p-bits: One step closer to probabilistic computing
Nanowerk August 29, 2022 To engineer probabilistic computers for more advanced computers researchers in Japan have developed a mathematical description to understand what happens to p-bits which could form the basis of probablistic computing. They utilized superparamagnetic tunnel junctions that have high sensitivity to external perturbations and determined the exponents through several independent measurements. They experimentally clarified the ‘switching exponent’ that governs fluctuation under the perturbations caused by magnetic field and spin-transfer torque in magnetic tunnel junctions. This gave them the mathematical foundation to implement magnetic tunnel junctions into the p-bit to sophisticatedly design probabilistic computers. They showed that these […]