Science Daily October 22, 2021 Researchers in Japan combined polyaniline, a conducting polymer that can be easily synthesized, with bagworm silk obtained from a bagworm nest. The composite fibers obtained from the silk and polyaniline were 2 microns in diameter and acted as optical waveguides. They demonstrated that green laser light propagates along these fibers, while remaining confined within each fiber. Using SQUID measurements they determined that the fibers can act as paramagnets. By applying the bagworm silk/polyaniline composite in a field-effect transistor device, the research team also confirmed that the composite fiber is suitable for use in textile transistors. […]
Tag Archives: S&T Japan
Teaching robots to think like us
Science Daily October 26, 2021 Researchers in Japan have taught a robot to navigate through a maze by electrically stimulating a culture of brain nerve cells connected to the machine. The neurons were grown from living cells and acted as the physical reservoir for the computer to construct coherent signals. The signals are regarded as homeostatic signals, telling the robot the internal environment was being maintained within a certain range and acting as a baseline as it moved freely through the maze. Throughout trials, the robot was continually fed the homeostatic signals interrupted by the disturbance signals until it had […]
All-nitride superconducting qubit made on a silicon substrate
Science Daily September 20, 2021 Researchers in Japan have developed superconducting qubits based on NbN/AlN/NbN epitaxial Josephson junctions on silicon substrates which promise to overcome the drawbacks of qubits based on Al/AlOx/Al junctions. The all-nitride qubits have great advantages such as chemical stability against oxidation, resulting in fewer two-level fluctuators, feasibility for epitaxial tunnel barriers that reduce energy relaxation and dephasing, and a larger superconducting gap of ~5.2 meV for NbN, compared to ~0.3 meV for aluminum, which suppresses the excitation of quasiparticles. By replacing conventional MgO by a silicon substrate with a TiN buffer layer for epitaxial growth of […]
A three-qubit entangled state has been realized in a fully controllable array of spin qubits in silicon
Phys.org September 10, 2021 Researchers in Japan have developed a device consisting of a triple quantum dot on a silicon/silicon–germanium heterostructure and controlled through aluminum gates. Each quantum dot can host one electron, whose spin-up and spin-down states encode a qubit. An on-chip magnet generates a magnetic-field gradient that separates the resonance frequencies of the three qubits, so that they can be individually addressed. They first entangled two of the qubits by implementing a two-qubit gate and then realized three-qubit entanglement by combining the third qubit and the gate. The resulting three-qubit state had a remarkably high state fidelity of […]
GaN-on-diamond semiconductor material that can take the heat – 1000 C to be exact
Nanowerk September 9, 2021 Researchers in Japan used the surface activated bonding (SAB) method to successfully bond GaN and diamond and demonstrated that the bonding is stable even when heated to 1,000°C. A 5.3 nm-thick intermediate layer composed of amorphous carbon and diamond is formed at the as-bonded heterointerface. As the team increased annealing temperatures, the layer thickness decreased suggesting the intermediate layer can be completely removed by optimizing the annealing process. As no peeling was observed at the heterointerface after annealing at 1000°C these results indicate that the GaN/diamond heterointerface can withstand harsh fabrications processes. The material shows promise […]
Energy harvesting technology based on ferromagnetic resonance
Phys.org August 24, 2021 Researchers in Japan demonstrated electrical charging using the electromotive force (EMF) generated in a ferromagnetic metal (FM) film under ferromagnetic resonance (FMR). In the case of Ni80Fe20 films, electrical charge due to the EMF generated under FMR can be accumulated in a capacitor; however, the amount of charge is saturated well below the charging limit of the capacitor. In the case of Co50Fe50, electrical charge generated under FMR can be accumulated in a capacitor and the amount of charge increases linearly with the FMR duration time. The difference between the Ni80Fe20 and Co50Fe50 films is due […]
High-rate magnesium rechargeable batteries move one step closer to realization
Science Daily August 23, 2021 Mg/S batteries are some of the most promising rechargeable batteries owing to their high theoretical energy density. However, their development is hindered by low electronic conductivity of S, sluggish Mg2+ diffusion in solid Mg–S compounds formed by discharge, and dissolubility of polysulfides into electrolytes. To address these problems researchers in Japan proposed liquid-S/sulfide composite cathode materials in combination with an ionic liquid electrolyte at intermediate temperatures (∼150 °C). The composite structure is spontaneously fabricated by electrochemically oxidizing metal sulfides, yielding liquid S embedded in a porous metal-sulfide conductive frame. They demonstrated the concept by a […]
Towards next-gen computers: Mimicking brain functions with graphene-diamond junctions
Science Daily August 4, 2021 Researchers in Japan designed graphene-diamond junctions that can mimic the characteristics of biological synapses and key memory functions, opening the doors for next-generation image sensing memory devices. They demonstrated optoelectronically controlled synaptic functions using junctions between vertically aligned graphene (VG) and diamond. The fabricated junctions mimic biological synaptic functions when stimulated with optical pulses and exhibit other basic brain functions such as the transition from short-term memory (STM) to long-term memory (LTM). The VG-diamond arrays underwent redox reactions induced by fluorescent light and blue LEDs under a bias voltage. The researchers attributed this to the […]
Dancing with the light: A new way to make crystals bend by shining light
Nanowerk July 30, 2021 Only very thin crystals (up to 20 microns) can show appreciable mechanical response. Researchers in Japan accidentally discovered that the photothermal effect causes a crystal to bend fast. To create a new, faster bending crystal and clarify the underlying mechanism, they exposed a thin salicylideneaniline derivative crystal to UV light and obtained substantial bending within approximately 1 second. However, the bend angle dropped rapidly with increasing crystal thickness, revealing that the bending was caused by photoisomerization. When they illuminated a thick (>40 microns) crystal with UV light, they observed an extremely rapid bending within several milliseconds, […]
Physicists Have Developed a New Way to Levitate Objects Using Sound Only
Science Alert July 26, 2021 There are significant limitations hindering acoustic tweezers for broad practical application. Although hemispherical arrays of acoustic transducers can be used to create the sound trap, creating just the right sound field to lift an object and move it far from the transducers is very difficult if there is a surface that reflects sound. Researchers in Japan have developed a technique splitting the transducer array into blocks and used an inverse filter to reproduce sounds based on the acoustic waveform. This helps optimize the phase and amplitude of each transducer channel to produce the desired acoustic […]