A5100681622- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Photochromic and Fluorescence Chemistry
- Porphyrin and Phthalocyanine Chemistry
- Microwave Engineering and Waveguides
- Acoustic Wave Resonator Technologies
- Crystallography and molecular interactions
- Microwave Dielectric Ceramics Synthesis
- Quantum Dots Synthesis And Properties
- Radical Photochemical Reactions
- Luminescence and Fluorescent Materials
- Advanced Antenna and Metasurface Technologies
- Photoreceptor and optogenetics research
- Advanced Frequency and Time Standards
- Chalcogenide Semiconductor Thin Films
- Photochemistry and Electron Transfer Studies
- Microwave and Dielectric Measurement Techniques
- Nonlinear Optical Materials Studies
- Semiconductor materials and devices
- Gyrotron and Vacuum Electronics Research
- Advanced Photocatalysis Techniques
- Perovskite Materials and Applications
- Antenna Design and Analysis
- Radio Frequency Integrated Circuit Design
- Organic Chemistry Cycloaddition Reactions
Ritsumeikan University
2017-2025
Japan Science and Technology Agency
2023-2024
Kyorin University
2019-2023
Gifu Prefectural Tajimi Hospital
2022
Nagoya University
2019
Shiga Medical Center
2019
Epson (United States)
2018
Aoyama Gakuin University
2013-2017
National Sagamihara Hospital
2014-2017
University of Toronto
2014
Improvements both in accuracy and speed are described for the technique of measuring microwave dielectric properties low-loss materials by using a rod resonator short-circuited at ends two parallel conducting plates. A effective surface resistance R/sub s/ plates is proposed to allow accurate measurement loss tangent tan delta. By means first-order approximation, expressions analytically derived estimating errors measured values relative permittivity epsilon/sub r/, delta, temperature...
Colloidally stable suspensions of lead halide perovskite nanocrystals are prepared from high-quality nanocrystal seeds. Perovskite with different layered crystal structures reported. These systems well suited for investigations the intrinsic photophysics and spectroscopy organic-inorganic metal perovskites.
Dielectric materials are continuing to play a very important role in the microwave communication systems. These key realization of low-loss temperature-stable resonators and filters for satellite broadcasting equipment, many other devices. High dielectric-constant critical miniaturization wireless systems, both terminals base-stations, as well handsets. In this paper, sequential evolution dielectric applications devices will be reviewed. This includes waveguides, ceramic materials,...
This paper describes a generalized study for the resonant modes of dielectric rod resonater placed between two parallel conducting plates. Dielectric and conductor losses are ignored. It is shown that there states in this resonator, trapped leaky states. In order to determine cutoff resonat frequencies state, numerical results given conditions dispersive characteristics waveguide. The field patterns hybrid also presented. For it be useful introduce complex angular frequency. Numerical...
Infrared (IR) light represents an untapped energy source accounting for almost half of all solar energy. Thus, there is a need to develop systems convert IR fuel and make full use this plentiful resource. Herein, we report photocatalytic H2 evolution driven by near- shortwave-IR (up 2500 nm) irradiation, based on novel CdS/Cu7S4 heterostructured nanocrystals. The apparent quantum yield reached 3.8% at 1100 nm, which exceeds the highest efficiencies achieved conversion reported date....
The optical property of an ionic metal nanocluster (NC) is affected by the interaction with counter ions. Here, we report that modification trianionic [Ag29(BDT)12(TPP)4]3- NC (BDT: 1.3-benzenedithiol; TPP: triphenylphosphine) silver(I) complexes led to intense photoluminescence (PL) in near-infrared (NIR) region. binding peripheral region Ag29 confirmed single-crystal X-ray diffraction (SCXRD) measurement, which further supported electrospray ionization mass spectrometry (ESI-MS) and...
Negative photochromism, in which a thermally stable colored form isomerizes to the transient colorless by light irradiation and back reaction occurs thermally, is advantageous its applications for photoswitching materials because visible can cause photochromic color change of materials. Moreover, be induced even on inside due absence reabsorption excitation photogenerated species. While several negative compounds have been reported, time scales are still slower than minutes, no available...
Benzo-annulated chromenes, i.e., naphthopyrans, are well-known photochromic molecules that undergo photochemical ring-opening reactions to form two colored open-ring isomers, the transoid-cis and transoid-trans forms, upon light irradiation. Though returns thermally uncolored closed form, fading rate of is extremely slow because its higher thermal stability. This behavior responsible for persistence residual color several minutes hours, prevents application such fast photoswitching...
We herein propose a new type of efficient neutral photoacid generator. A photoinduced 6π-electrocyclization reaction photochromic triangle terarylenes triggers subsequent release Brønsted acid, which took place from the photocyclized form. H-atom and its conjugate base were introduced at both sides 6π-system to form self-contained UV irradiation produces cyclohexa-1,3-diene part with on sp(3) C-atoms 5- 6-positions, respectively, spontaneously an acid molecule quantitatively forming...
Switching of a hologram is realized with photochemical switching. A real-time dynamic realistic 3D object achieved by using fast photochromic imidazole dimers. As compared to conventional holographic materials, whose updating speeds the holograms still need be improved, dimer achieves speed, realizing object. This demonstration proves potential for molecules act as materials. service our authors and readers, this journal provides supporting information supplied authors. Such materials are...
We report a novel photochromic molecular system, phenoxyl-imidazolyl radical complex (PIC), in which both phenoxyl site and an imidazolyl are reversibly simultaneously generated upon UV light irradiation. PIC consists of the three parts: aromatic linker, diarylimidazole moiety, 4H-cyclohexadienone ring. Upon irradiation, C-N bond between ring imidazole colorless closed-ring isomer undergoes homolytic cleavage, leading to formation transient colored open-ring isomer. Based on substituents...
Stepwise two-photon processes not only have great potential for efficient light harvesting but also can provide valuable insights into novel photochemical sciences. Here we designed a [2.2]paracyclophane-bridged bis(imidazole dimer), molecule that is composed of two photochromic units and absorbs photons in stepwise manner. The absorption the first photon leads to formation short-lived biradical species (half-life = 88 ms at 298 K), while additional by triggers subsequent reaction afford...
This paper reports on durable and nearly temperature-independent (at 298–328 K) T-type photochromism of colloidal Cu-doped ZnS nanocrystals (NCs). The color NC powder changes from pale yellow to dark gray by UV light irradiation, the back a time scale several tens seconds minutes after stopping while decoloration reaction is accelerated submillisecond in solutions. much faster than those conventional inorganic photochromic materials. origin reversible photoinduced coloration revealed be...
Perturbation formulas for TE/sub 011/-mode dielectric rod resonator and a circular cavity are derived to determine the surface impedance Z/sub s/ of superconductors from measured values resonant frequencies unloaded Q. The relation between maximum current density superconductor, J/sub s/, output power signal generator is derived. On basis these analytical results, measurement technique proposed evaluate temperature dependencies superconductors. results dependence YBCO copper plates...
The effect of surface states originating from defects and capping reagents on Auger recombination in CdS quantum dots (QDs) are investigated by femtosecond transient absorption spectroscopy. Because the strong size-dependent nature defects, size dependence is also conducted to reveal states. lifetime very similar irrespective all regions was proportional D6 (D: QD diameter). This result clearly shows that QDs does not depend interfacial electronic structures one monolayer level.
Light-selective multiple photochromic systems are important for advanced photoswitching of chemical reactions and biological activities. While UV light has been frequently utilized to induce reactions, visible is energetically acceptable avoid undesired reactions. However, many the reported multiphotochromic still rely on at least a part In this work, we designed biphotochromic molecule showing intensity-dependent coloration with visible-light source by incorporating two T-type units;...
Controlling the carrier dynamics in a semiconductor nanoparticulate photocatalyst is key to developing catalytic activity. Generally, type I band alignment unsuitable for photocatalysts because photoinduced carriers accumulate narrow bandgap semiconductor. To avoid termination of reactions and/or photocorrosion materials caused by accumulation, it common employ II photoenergy conversion systems instead I. However, CdS/ZnS core/mesoporous-shell heterostructures show superior photocatalytic...
Stepwise two-photon excitations have been attracting much interest because of their lower power thresholds compared with simultaneous processes and some stepwise can be initiated by a weak incoherent excitation light source. Here we apply optical to the photochromic bridged imidazole dimer, whose solution instantly changes color upon UV irradiation quickly reverts initial thermally at room temperature. We synthesized zinc tetraphenylporphyrin (ZnTPP)-substituted wide ranges time-resolved...
There has been a growing interest toward the development of advanced photofunctional materials whose photoresponses involve multiple photons and molecules because these show which cannot be achieved by one-photon reaction single chromophore. These cooperative interactions are recently termed as "photosynergetic" effects, understanding utilization effects becoming important research topics. In this Perspective, we overview recent progress fast T-type photochromic involving stepwise two-photon...
Rigorous field analysis by the mode-matching method is presented for dielectric rod resonators, including such uniaxial dielectrics as sapphire, which are placed between two parallel conducting plates or in a cavity. The wave equations E/sub Z/ and H/sub anisotropic medium derived cylindrical coordinate system. Based on these equations, characteristic resonator structures can be used to calculate resonant frequencies of any mode. Cutoff conditions modes discussed parallel-plate-type...
Two approaches due to the complex frequency and perturbation theory are described compute accurately Q-factors of circularly-symmetric TEO modes for dielectric rod resonators placed between two parallel conductor plates in a cavity. These techniques allow us estimate separately radiation, conductor, losses from only computation resonant frequencies by means mode-matching method. Validity theories is verified experiments. The influence shields on discussed computed results. A possibility...