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The first regioselective addition reactions to 3-trifluoromethylbenzyne are reported. Triple cycloaddition of ynolates to the benzyne provided 1,8,13-tris(trifluoromethyl)triptycenes with high regioselectivity. 1-Trifluoromethyltriptycenes were regioselectively obtained by the Diels–Alder reaction of anthranoxides with the benzyne. These selectivities are attributed to the electron-acceptor nature of the trifluoromethyl group on the benzyne.

The rhabdophane-type YPO4 particles have been synthesized in the presence of citrate ions under systematically varied reaction conditions.

Satellite-based gross primary production (GPP) estimation has uncertainties due to shadow fraction caused by the geometric relationship between the complex forest structure and the Sun. The virtual forests allow shadow fraction estimation without 3D measurements, but require optimal structural parameters. In this study, we developed the reflectance simulator (Canopy-level Shadow and Reflectance Simulator, CSRS) that considers tree shadows and the method to determine the optimal canopy shape for shadow fraction estimation. The target forest is any tropical evergreen forest which accounts for 58% of tropical forests. Firstly, we analyzed the effects of canopy shape on the reflectance simulation based on virtual forests created with different canopy shapes. This result was checked by Tukey’s honestly significant difference (HSD) test. Secondly, the optimal canopy shape was determined by comparing the reflectance from Sentinel-2 Band 4 (red) bottom of atmosphere reflectance with those simulated from virtual forests. Finally, the shadow fraction estimated from the virtual forest was evaluated. Since the focus of this study was to derive the optimal canopy shape, unmanned aerial vehicle (UAV) structure from motion (SfM) was used to obtain the parameters other than canopy shape and to validate the estimated shadow fraction. The results showed that when the Sun zenith angle (SZA) was more than 20°, significant differences were observed among canopy shapes. The least root mean square error (RMSE) for reflectance simulation was 0.385 from the canopy shape of a half ellipsoid. Moreover, the half ellipsoid also showed the smallest RMSE in estimating shadow fraction (0.032), which indicated the reliability and applicability of CSRS. This study is the first attempt to determine the optimal canopy shape for estimating shadow fraction and is expected to improve the accuracy of GPP estimation in the future.

Optical modulation based on second-order optical nonlinearity is required to control a light-wave for telecommunication with optical-fiber network, and its controlling device is basically constructed using a single crystal material. To fabricate an optical device material having the connectivity to glass fiber, glass-ceramic (GC) processing is effective. In this study, a bulk-like GC material with a polar fresnoite-type Ba2TiGe2O8 were successfully fabricated. The obtained GCs were formed by densely-aggregated structure of two phase, fresnoite-type (major phase) and tetragermanate (minor phase). The fresnoite-type Ba2TiGe2O8 domains with submillimeter-sized were oriented with the polar c-axis perpendicular to sample plane. The GC sample exhibited the optical modulation driven by Pockels effect, and the Pockels coefficients could be quantitatively estimated, i.e., r13 = 2.3 ± 0.1 pm/V and r33 = 2.5 ± 0.1 pm/V. The experimental results demonstrate the potential of higher Pockels coefficients by microscopic structural studies, because of good controllability of the polar orientation and suppression of secondary phase.

We have fabricated the glass-ceramic fiber, in which nonlinear-optical Sr2TiSi2O8 phase was radially crystallized. Optical intensity modulation based on Pockels effect was successfully demonstrated in the fiber.

Aiming to fiber-type active optical-device, we have developed novel glass-ceramics consisting of nonlinear optical crystal. The radially-crystallized glass-ceramic fiber has been demonstrated to show an optical modulation based on Pockels effect.

We succeeded in developing the glass-ceramic fiber consisting of optical nonlinear crystal, and demonstrated its propagation loss to be comparable to that of LiNbO3 waveguides.

Glass products with precise and sophisticated shapes are highly demanded in the field of MEMS due to their excellent properties. Ultrashort pulsed laser has been expected to be a powerful and reliable tool for micro-welding of glass. Focusing condition such as numerical aperture (N.A.) is a critical parameter that controls how ultrashort laser pulses interact with and propagate in glass, and it has a great influence on the laser micro-welding characteristics of glass. In order to investigate the quality of welding process, it is important to understand the dependence of the mechanical strength of molten area created in glass specimen with various numerical apertures. Therefore, the mechanical strength of molten area with various numerical apertures was evaluated in micro-welding of glass by picosecond pulsed laser. Higher bending strength could be obtained under an appropriate volume ratio of molten area and glass specimen, when continuous molten areas were formed. In addition, high density and large size of molten area without crack led to higher breaking stress. It is concluded that superior focusing characteristics such as N.A. 0.65 enable a long region of high power density in beam axis, which can satisfy both high mechanical strength and high processing speed.

Clarifying the molecular mechanisms by which bacteria acquire virulence traits is important toward understanding the bacterial virulence system. In the present study, we utilized a bacterial evolution method in a silkworm-infection model and revealed that deletion of the opgGH operon encoding synthases for osmoregulated periplasmic glucan (OPG) increased the virulence of non-pathogenic laboratory strain of Escherichia coli against silkworms. The opgGH knockout mutant exhibited resistance to the host antimicrobial peptides and antibiotics. Compared with the parent strain, the opgGH knockout mutant produced greater amounts of colanic acid, which is involved in E. coli resistance to antibiotics. RNA sequence analysis revealed that the opgGH knockout altered the expression of various genes, including the evgS/evgA two-component system that functions in antibiotic resistance. In both a colanic acid-negative background and evgS-null background, the opgGH knockout increased E. coli resistance to antibiotics and increased the silkworm killing activity of E. coli. In the null background of the envZ/ompR two-component system, which genetically interacts with opgGH, the opgGH knockout increased the antibiotic resistance and the virulence in silkworms. These findings suggest that the absence of OPG confers antimicrobial resistance and virulence of E. coli in a colanic acid-, evgS/evgA-, and envZ/ompR- independent manner. IMPORTANCE The gene mutation types that increase bacterial virulence of Escherichia coli remain unclear, in part due to the limited number of methods available for isolating bacterial mutants with increased virulence. We utilized a bacterial evolution method in the silkworm infection model, in which silkworms were infected with mutagenized bacteria and highly virulent bacterial mutants were isolated from dead silkworms. We revealed that knockout of OPG synthases increases E. coli virulence against silkworms. The OPG-knockout mutants were resistant to host antimicrobial peptides as well as antibiotics. Our findings not only suggest a novel mechanism for virulence acquisition in E. coli, but also support the usefulness of utilizing the bacterial experimental evolution method in the silkworm infection model.

We have fabricated perfectly-surface-crystallized glass-ceramics (PSC-GCs) consisting of polar frenoite-type Sr 2 TiSi 2 O 8 by different crystallization-process conditions, i.e., isothermal treatment at 880 °C for 72 h and 960 °C for 1 h, and have examined their Pockels effect in this study. The PSC-GCs obtained by the lower-temperature process exhibited the Pockels coefficients, i.e., r 13 ∼ 3.0 pm/V and r 33 ∼ 2.4 pm/V, and the coefficients exceeded the reported values of the PSC-GCs with Sr 2 TiSi 2 O 8 phase. The improvement of Pockels effect is attributed to the higher crystal-orientation, which is provided by the lower-temperature condition.

1,8,13-Trialkyl(aryl)silyl-9-hydroxytriptycenes (trisilyltriptycenes) were synthesized by the triple addition of ynolates and 3-silylbenzynes with high regioselectivity. Benzene rings in the resulting triptycenes were highly distorted where the dihedral angles between the substituents were as high as 35°. The distortion energy induced step-by-step halogenation reactions to yield halogenated triptycenes, including chiral triptycenes. The 1,8,13-trihalogenated triptycenes were then converted to 1,8,13-functionalized triptycenes.

Recently, we have developed the borosilicate glass, in which ZrO2 phase is singly crystallizable, and has found an emissive monoclinic ZrO2 dendrites in the resulting GCs. In order to promote the formation of monoclinic phase, we have examined the effect of substitution of alumina Al2O3 for ZrO2 in the precursor glass composition, i.e., 15Na2O–(15 − x)ZrO2–xAl2O3–30B2O3–40SiO2. It was found that the substitution of small amount of Al2O3 (x = 1) gave a positive effect, i.e., increase in the amount of monoclinic phase and decrease in the crystal size. Furthermore, the substitution improved the internal quantum-yield. On the other hand, the further substitution (x ≥ 2) provided the decrease in amount of the monoclinic phase.

Dynamic control of heat flow for applications in thermal management has attracted much interest in fields such as electronics and thermal engineering. Spin-chain ladder cuprates are promising materials to realize dynamic control of heat flow, since their magnon thermal conductivity is sensitive to the hole density in the spin ladders, which can be dynamically controlled by an external field. Here, we demonstrate the electric control of heat flow using a polycrystalline cuprate film and an ionic liquid. The results showed that a voltage application to the interface causes imperfectly recoverable decreases in both the thermal conductance of the film and the peak due to magnons in the Raman spectra. This result may be attributed to an increase in the hole density in the spin ladders. This report highlights that magnon thermal conduction has potential for the development of advanced thermal management applications.

Oxide glass is an industrial material with advantages such as optical transparency and shaping ability of the melt, but at the same time, it is a bad conductor of heat due to its disordered structures. Therefore, heat dissipation in glass components often becomes a problem and its applications to the thermal management has been limited to use as a heat insulator. To break this mold and to apply it to fields, e.g., transparent sealing materials, for which low thermal conductive glasses and organic polymers have been conventionally used, we fabricated an MgO-dispersed glass-ceramics in our previous work. It comprises MgO crystal and glass matrix and their reflective indices are matched, leading to optical transparency and improvement in thermal conductivity. Here we investigate the atomic-scale structures in the MgO-dispersed glass-ceramics by nuclear magnetic resonance, etc. and attempt to further improve the thermal conductivity and the transparency. As a result, we show an MgO-dispersed glass-ceramic with a thermal conductivity of 3.3 W (m−1 K−1), corresponding to 300% of that of the glass matrix, high optical transparency, and glass transition. This report highlights that our strategies pave the way for development of novel transparent, functional glass-ceramics.

Chemically strengthened glass is widely used for screen protection in mobile devices, and its strengthening processes and application fields have rapidly diversified. The origin of the strength is residual compressive stress induced by ion exchange, and the stress evaluation has been performed via the photoelastic effect. However, for a deep understanding of the nature of the strength and development of stronger glasses, we need a method directly connected to atomic-scale glass structures. Here, we propose a method based on the “stuffing” effect, where we can determine the residual stress non-contactively and non-destructively with a high spatial resolution using Boson, D1, D2, and A1 peaks in micro-Raman spectra. Finally, we show a plausible depth dependence of the residual stress. The strength of glass can be increased post-production by treatment with chemical processes, and such materials are used in everyday devices such as mobile phones. Here, the authors report a non-invasive method based on micro-Raman spectroscopy to analyse the compressive stress responsible for the increased strength of the treated glass.

Phase change material (PCM), which enables heat storage based on phase transition, plays an important role for efficient energy utilization. This paper briefly describes our recent study about all-solid PCM by combination of vanadium dioxide (VO2) with latent heat storage capacity and multicomponent glass, i.e., VO2-dispersed glass. A B2O3-P2O5-V2O5 glass system is used as a matrix for the VO2-dispersed glass. An attempt to describe its latent heat storage function is given. Endothermic behavior due to structural phase transition of the VO2 crystals was observed in the VO2-dispersed sample, and the transition enthalpy corresponding to latent heat storage capacity was estimated to be ΔH~9.5 J/g. The value of the studied sample was larger than the value of dispersed glass in the BaO-TeO2-V2O5 system that was previously reported. Potential for PCM was considered in the studied sample.

We have investigated atomic-scale structures in 2-step ion-exchanged strengthened glasses by using polarized micro-Raman spectroscopy for non-destructive evaluation of the compressive stress.

We investigated the long-lasting photoluminescence (LLP) properties in a commercial zirconia powder with a monoclinic system after thermal treatment at different temperatures. Clear-blue photoluminescence and LLP were observed in the zirconia without emissive dopants subjected to thermal treatment at 1400 °C. Decay curve measurements revealed a pronounced, visually observable bluish LLP that lasted for ~ 10 h at moderate temperature. Based on spectroscopic observation and electron spin resonance results, a possible origin of the LLP is discussed.

Development of minimally invasive and site-selective biological temperature sensing is quite important in medical field. This study presents a novel temperature sensing technique based on afterglow and optically-stimulated luminescence (OSL). The dependence of afterglow photoluminescent intensity on the environmental temperature of zirconia (ZrO2) phosphor is examined to validate its use as a sensing probe. In addition, assuming the measurement in deep-part of human body, we have applied the information gathered from our validation to observe OSL from the ZrO2 by irradiation with near-infrared laser through a bone sample. This study demonstrates an alternative medical application of phosphor, and introduces an elemental-technology for the temperature sensing.

We report a novel coating method for TiO2 anatase thin-film fabrication via a top–down sol–gel deposition method using NH4TiOF3 single crystals. A cationic nitrogen-rich porphyrin compound was used to fabricate N-doped TiO2 nanofilms that showed highly efficient photocatalytic activity under visible-light irradiation.

Chemically strengthened glass has become essential in our daily lives and the demand is rapidly increasing in a variety of fields. However, the conventional cutting process is not applicable because of its tough layer with the compressive stress. To achieve higher-throughput production of the glass, we report spatially selective weakening of the compression layer by CO2 laser scanning and provide its visualization by Raman mapping. We demonstrate cutting the scanned glass without shattering using a typical scribing wheel. Finally, we discuss the improvement in processability from the viewpoint of microscopic structures by means of thermal analysis and Raman spectroscopy.

Study on visible light response of photocatalytic materials is very important research area for future energy society. Generally, in conventional photocatalysts, visible light response is provided by defect introduction. This phenomenon is based on formation of trap level between valence and conduction band. In our previous report, we have already succeeded in observing the photocatalytic activity of TiO 2 crystallized glass. Since glass-based material is suitable for industrial use, crystallized glass is expected to be a novel bulk photocatalyst with high productivity if we provide visible light response ability to TiO 2 crystallized glass. In this study, we tried the defect introduction to TiO 2 crystallized glass and investigated the photocatalytic activity under visible light irradiation. As a result, we have demonstrated water splitting by TiO 2 crystallized glass with Ti 3+ defect under visible light irradiation for the first time.

We demonstrate a novel top-down synthesis of photocatalytic nanocomposites coupled with multi-walled carbon nanotubes (MWCNTs). TiO2 nanoparticles were directly grown on and fully covered the MWCNTs' surface via room-temperature hydrolysis of NH4TiOF3 micro-single crystals. A similar full coating of TiO2 was extended to graphene oxides (GOs). X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET) surface area analysis were employed for characterization of products. The photocatalytic activities of the MWCNT/TiO2 nanocomposites are strongly influenced by the TiO2 coverage on the MWCNTs. Among the synthesized nanocomposites, the 4.9% MWCNT/TiO2 nanocomposite demonstrated the highest photodegradation as well as the lowest adsorption of methylene blue (MB). Keywords: Nanocomposites, Multi-walled carbon nanotubes, Graphene oxides, TiO2 nanoparticles, NH4TiOF3 single crystals, Photodegradation

The shadow fraction of the canopy is an important factor in Bidirectional Reflectance Distribution Function (BRDF) and in estimating physical quantities, such as tree height and biomass. Shadows are used as a shielding ratio for direct solar irradiance, but, at shorter wavelengths, the amount of diffuse solar irradiance is greater, so the shielding ratio cannot be ignored. The shielding ratio of direct and diffuse solar irradiance is called Cast Shadow (CS) and Self Cast Shadow (SCS), respectively, however, it has been pointed out that the effect of these shadows is greater at higher resolutions, such as Sentinel-2. In addition, the Bottom Of Atmosphere (BOA) reflectance is greatly affected by shadows, because it is corrected for atmospheric effects. Therefore, the main purpose of this study is to investigate the spatial variability of CS and SCS and simulate the Sentinel-2BOA reflectance with these shadows. The target forest was a greenness season of a deciduous broadleaf forest in Thailand. First, we obtained a point cloud of the forest by Structure from Motion while using the Unmanned Aerial Vehicle. Next, we created a voxel model with CS and SCS as attributes. CS was calculated as the percentage of area where the plane that is assumed per voxel is shielded from direct solar irradiance by other voxels. SCS was calculated as the percentage of area where the hemispheric radiant environment is shielded by other voxels. Subsequently, using solar irradiance and leaf spectral reflectance data, the reflectance of each band of Sentinel-2 was simulated. Nine leaves were used to investigate the effect of leaf species on the simulation. The reflectance acquired by Sentinel-2 is not at the leaf level, however, we used this spectral reflectance data because the reflectance was simulated at the same spatial resolution as the voxel size. Voxel sizes of 20 cm, 50 cm, 100 cm, and 200 cm were used. Our result showed that (1) the spatial variability of SCS was smaller than that of CS when the sun position is fixed and the view zenith angle is changed. SCS was mostly 0.12 at different zenith angles, while the CS had a maximum value of 0.45 and a minimum value of 0.15. (2) The accuracy of the simulations was evaluated using the Root Mean Square Error (RMSE). The best RMSE is 0.020 &plusmn, 0.015 and the worst one is 0.084 &plusmn, 0.044. It was found that the error is larger in short wavelength infrared bands. (3) In this forest, the relative reflectance changed only about 1.2 times as much, as the voxel size was increased from 20 cm to 200 cm. In this study, we have simulated a single Sentinel-2 image. In the future, we will simulate multi-temporal images in order to investigate the effects of phenology and shadow changes on the reflectance that was observed by optical sensors.

We prepared SrCuO 2 film by radio-frequency magnetron sputtering on silica glass and have investigated structure change induced by super-band-gap light. An X-ray diffraction pattern shows that the as-sputtered film is composed of (001)-oriented SrCuO 2 nanothick crystals belonging to tetragonal system, i.e., the layer-type SrCuO 2 . Raman-scattering spectra show that irradiation of high-power super-band-gap laser light onto the film gives rise to structure change into orthorhombic system, i.e., the chain type SrCuO 2 , which is known to exhibit high, anisotropic thermal conductivity due to spin interaction. A mechanism of the structure change is discussed in terms of photoexcitation and heating process.