A5064118802- Physics of Superconductivity and Magnetism
- Superconducting and THz Device Technology
- Gyrotron and Vacuum Electronics Research
- Photonic and Optical Devices
- Liquid Crystal Research Advancements
- Photochromic and Fluorescence Chemistry
- Terahertz technology and applications
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Photonic Crystals and Applications
- Radical Photochemical Reactions
- Photoreceptor and optogenetics research
- Acoustic Wave Resonator Technologies
- Catalytic C–H Functionalization Methods
- Semiconductor Lasers and Optical Devices
- Porphyrin and Phthalocyanine Chemistry
- Advanced optical system design
- Structural Load-Bearing Analysis
- Spectroscopy and Laser Applications
- Axial and Atropisomeric Chirality Synthesis
- Semiconductor Quantum Structures and Devices
- Asymmetric Synthesis and Catalysis
- Asymmetric Hydrogenation and Catalysis
- Sulfur-Based Synthesis Techniques
- Superconductivity in MgB2 and Alloys
Hokkaido University
2024
Sanken Electric (Japan)
2023
Osaka University
2021-2023
Nagoya University
2001-2022
University of Manchester
2022
University of Tsukuba
2016-2019
Gunma University
2019
QuTech
2017-2018
University of Central Florida
2017-2018
Delft University of Technology
2017-2018
Azo-crown ether-based photoswitching chiral phase transfer catalysts have been developed to control the catalytic activity by photoirradiation. Azobenzene binaphthyl crown ether (ABCE) can switch its reactivity and selectivity through structural transformation of moiety induced E/Z photoisomerization azobenzene. (Z)-ABCE promoted enantioselective alkylation glycine Schiff base afford amino acid derivatives in good yields with high enantiomer ratios. In contrast, (E)-ABCE hindered reaction...
Indoles are among the most important N-heterocycles in pharmaceuticals. Here, we present an alternative to classic Fischer indole synthesis based on radical coupling between aryl diazoniums and alkyl iodides. This iron-mediated strategy features a double role for that sequentially activate iodides through halogen-atom transfer then serve as acceptors. The process operates under mild conditions enables preparation of densely functionalized indoles.
Substituted cyclic alcohol is one of the pharmaceutically essential scaffolds. Here, we report photoredox/cobalt-catalyzed reductive cyclization alkynals using H2O for catalyst turnover. This method was applied to aliphatic and aromatic aldehydes five-, six-, seven-membered (heterocyclic) ring formation with various substitutions on alkyne units. H2O-added protocol further developed into a one-pot transformation from acetals through in situ generated aldehydes, which shortened synthetic path...
A terahertz (THz) wave emitter using the stack of intrinsic Josephson junctions present in high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi2212) has been developed. By applying a dc voltage V across stack, ac-Josephson effect converts this to an ac-current that emits photons at frequency proportional V. The Bi2212 device also behaves as and electromagnetic (EM) cavity, so depending upon shape crystal, when matches cavity resonance, emission power is enhanced. However, EM radiation characteristics...
We propose a liquid crystal (LC) micro-lens array with the structure of two-divided and tetragonally hole-patterned electrodes. Each LC cell in lens behaves like cylindrical or spherical properties by electrically adjusting applied voltages. The is useful for tuning optical such focal length deflection angle light emitting diode (LED) illumination system.
An azopyridine-based oxazoline ligand was developed as a chiral photoswitchable ligand. The coordinated to rare-earth metal modulated the enantioselectivity of cyclic aminal forming reaction by photoisomerization.
Using our recent design of thermally managed sandwich device structures, we studied the radiation frequency characteristics three such devices same rectangular dimensions made from single crystal high-Tc superconductor Bi2Sr2CaCu2O8+δ, and all exhibit similar characteristics. Their observed intensities appear to be enhanced at many transverse magnetic TMn,m cavity mode frequencies, possibly including some higher TM0,m modes with waves solely along length, none which have previously been...
Planar chiral [2.2]paracyclophane-based phosphine–phenols efficiently catalyze the [3 + 2] annulation of<italic>N</italic>-tosylimines and allenoate.
Joule heating is the central issue in order to develop high-power and high-performance terahertz (THz) emission from mesa devices employing intrinsic Josephson junctions a layered high transition-temperature Tc superconductor. Here, we describe convenient local thermal measurement technique using charge-coupled-device-based thermoreflectance microscopy, with highest spatial resolution date. This clearly proves that relative temperature changes of between different bias points on...
Design of a suitable photoswitchable chiral cation-binding cage for the synthesis optically active aminals was established using azobenzene-BINOL hybrid oligoethylene glycol (ABOEG) through E/Z isomerization azobenzene unit. Under photoirradiation, both catalytic activity and enantioselectivity generating (Z)-ABOEG are enhanced, in contrast to that (E)-ABOEG, which can be attributed geometrically distinct coordination behavior between metal cation glycols.
Bis(dithienylethene)-based BINOL-derived phosphoric acid (DTE-BPA) has been developed as a light-controlled chiral organocatalyst for the first time. The photoinduced modulation of reactivity and selectivity via open/close isomerization DTE scaffold led to superior ability in enantioselective aza-Friedel-Crafts reaction aldimines with indoles. DFT studies showed that photoisomerization is accompanied by shift 1.1 pKa units between open closed isomers.
This paper presents the electrical characteristics of NbN/Nb/AlOx/(Nb)/NbN junctions fabricated using an ultra-high vacuum (UHV) dc-magnetron sputtering system. The show overdamped at or over 10 K, although they small- medium-hysteretic 4.2 K. UHV system with a load-lock chamber enables us to prepare high-quality NbN films high reproducibility and very thin Al2O3 homogeneity. We have obtained critical current density Jc up kA cm-2 characteristic voltage Vc 0.50 mV When Al oxidation...
Abstract Continuous and monochromatic terahertz electromagnetic waves can be generated with sizable power (∼30 μW) by the mesa-shaped device made of high- T c superconductor Bi 2 Sr CaCu O 8+δ , synchronizing phase Josephson currents between multi-stacked intrinsic junctions. From previous experimental results on line width, spatial distribution emission, etc. we think that relatively weaker may originate from partial failure synchronization in mesa device. This improved modifying structure...
We propose a liquid-crystal (LC) micro-lens array with flat external electrode in addition to two-divided and square-shaped electrodes for electrically controlling cylindrical or spherical lens properties each LC cell of the array. The is useful tuning optical such focal length deflection angle light emitting diode illumination system.
We propose a liquid crystal (LC) micro-lens array with two-divided and hexagonal-hole-patterned electrodes for varying focal length beam deflection angle. The possibilities of lens-like refractive index distributions in the hexagonal region LC are discussed. investigate optical properties such as by measuring transmitted light intensity distributions.
Using amines in catalytic transfer hydrogenation (TH) is challenging, despite their potential availability as a hydrogen source. Here, we describe photoredox/nickel-catalyzed TH of alkyne through an intermediary aminoalkyl Ni species. This reaction successfully provided functionalized (Z)-alkenes, such (homo)allyl ethers, alcohols, and amides (Z/E = up to >99:1), the thus bypasses limitation substrate scope using amine Lindlar catalyst. Mechanistic studies revealed that species plausibly...
津波の河川遡上・氾濫流解析においては，流れの三次元性を考慮でき，種々の現象を一体的に解析が可能な実用的なモデルが求められている．本研究では，平面二次元解析の枠組みで流速と圧力の鉛直分布を考慮できる一般底面流速解析法を水面の時空間変化の激しい津波解析に応用するため，鉛直方向流速の非定常項と水面での圧力鉛直勾配項を新たに導入した非静水圧津波準三次元解析法を開発した．まず，本解析法を津波河川遡上実験に適用し，実験結果と平面二次元解析法の計算結果との比較から，本解析法の妥当性，有用性を示した．次に，本解析法を用いて，北上川の今次津波の再現解析を行った．計算結果は，全体的な痕跡と津波の到達時間などの特徴を再現した．しかし，計算水位が痕跡水位よりも大きく見積もられており，この差が生じる原因を考察した．
Chiral photoswitchable catalysts can modulate reactivity and selectivity of enantioselective reaction by photoisomerization. While a variety the have been developed due to their utility in field asymmetric synthesis, azobenzene, which is readily available well-known photoresponsive unit, has rarely applied chiral catalysts. We azobenzene-based organocatalysts ligand such as azobenzene BINOL crown ether (ABCE), hybrid oligoethylene glycol (ABOEG), azopyridine-oxazoline (AZOX). The (Z)-ABCE...
This paper describes electrical characteristics of NbN junctions with Nb/Al/sub 2/O/sub 3/-Al/(Nb) multilayered barriers. The show overdamped behavior at 10 K because Nb working as a normal layer, which enables us to use them basic elements in single flux quantum (SFQ) circuits. junctions, critical current densities J/sub c/'s up 3.4 kA/cm/sup 2/ and characteristic voltages V/sub 0.20 mV, were obtained by changing the film thicknesses lower upper layers Al oxidation conditions when using...
ABSTRACT We developed a one‐pot reaction combining an exchange of the benzylidene moiety in acyl hydrazone with styrene radical polymerization. The derivative bearing 4‐(dimethylamino)benzylidene was conducted presence 4‐cyanobenzaldehyde and pyridinium p ‐toluene sulfonate/H 2 O for AIBN as polymerization initiator N , ‐dimethylformamide at 70 °C 20 h. proceeded quantitatively, being exchanged 4‐(methoxy)benzylidene hydrazone, smoothly to provide corresponding polymer 70% yield. Compared...
Most of the previous research on acquisition LED Array transmitter assumes that onboard receiver approaches from car’s front. In this study, we considered a case where vehicle’s crosses transmitter. This letter modifies algorithm using spatial-temporal gradient values to detect arrays. As result, achieved error-free and successfully communicated up 9728 [bits] at vehicle speed 25 [km/h].
Liquid crystal (LC) director distributions and optical phase profiles in LC micro-lens-array (LC-MLA) are studied by using a three-dimensional (3D) numerical calculation method. The LC-MLA design employs twodivided tetragonally-patterned electrode structure flat nematic cell. possibilities of prism lenslike difference the rectangular aperture region discussed. molecular orientation can be estimated its profile predicted fairly well calculations.