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Traditionally, the stuffing model has been used to describe stress generation in chemically strengthened glass. Nevertheless, the associated unrealistic conditions, including an imaginary volume expansion and its suppression in an adiabatic closed system, inhibit a thorough understanding of the process. In this study, we propose a thermodynamic model in an isothermal open system to enable ion exchange without an imaginary volume expansion. We derive a fundamental equation and verify it using atomistic images obtained by Raman spectroscopy and nuclear magnetic resonance. This study paves the way for further atomistic design and development of strengthened glasses. [ABSTRACT FROM AUTHOR]

We have shown that typical amorphous chalcogenides, As2S3 bulk with a thickness of 50–100 μm and fiber with a diameter of 100 μm, can be bent by controlling the orientation of linearly polarized light. The bending of the bulk and fiber with thickness and diameter comparable to the optical penetration depth is efficiently generated by irradiation with a light of 2.33 eV, corresponding to the optical bandgap of amorphous As2S3. We have evinced that the bent phenomena of the amorphous As2S3 bulk and fiber are dominantly due to photo-induced anisotropy, fluidity, and optical torque effects. Then, the optical torque when bending occurred on the As2S3 fiber was quantitatively evaluated as ~ 10−7 N‧m in the case of 20 W/cm2 irradiation. The bending of the As2S3 bulk glass and fiber due to the temperature rise by bandgap light irradiation is not dominant. [ABSTRACT FROM AUTHOR]

Spin-chain–spin-ladder cuprates, such as La5Ca9Cu24O41, have notable electronic and thermal properties because of their unique electron spin arrangement. Among them, magnon thermal conductivity, which originates from the excitation of paired electron spins, is promising for the advanced thermal management applications that enable dynamic control of heat flow. This is because of its high, anisotropic thermal conductivity at room temperature and its dynamic controllability. In this study, we report nanosheet fabrications from polycrystalline La5Ca9Cu24O41 to enhance the control width. We obtained that the nanosheets with a thickness of about 3 nm are obtained via immersion of the polycrystals in a NaOH aqueous solution. We propose the exfoliation model based on the chemical reaction between the (La/Ca)2Cu2O3 subsystem and NaOH solution. The nanosheet fabrications can also lead to new research development on spin-ladder system and other strongly correlated cuprates. [ABSTRACT FROM AUTHOR]

Photoluminescence provides information about the surrounding environment. In this study, aiming to develop a non-invasive deep body-temperature sensing method, we investigated photoluminescence properties of afterglow zirconia (ZrO2) by pulsed near-infrared (NIR) light irradiation based on the biological temperature. Pulsed light irradiation produced optically stimulated luminescence, followed by afterglow, with the property of repeating 100 times or more. Furthermore, the basic principle of temperature measurement was demonstrated through afterglow decay curve measurements. The use of harmless ZrO2 as a sensing probe and NIR light, which is relatively permeable to living tissues, is expected to realize temperature measurements in the brain and may also facilitate optogenetic treatment. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

We have fabricated a rechargeable photo-chemical battery using ion-hole conducting AgAsS2 films. An asymmetrically-electroded Al/AgAsS2/SnO2 yields photocurrents and upon illumination it is concomitantly charged up. When the illumination is stopped, the stack discharges electricity into an external circuit. This photo-charging and discharging phenomenon is attributed to a photo-chemical modification of Ag-ion distribution in amorphous AgAsS2. [ABSTRACT FROM AUTHOR]

Oxide glasses generally have low thermal conductivity due to their disordered structures. Here, a fabrication method to provide them with high thermal conductivity while retaining their optical transparency is proposed. It consists of dispersing ∼20 μm MgO crystals in a glass matrix and matching their refractive indexes to prevent the decrease of the oxide glass optical transparency due to light scattering. The dispersion of the MgO crystals increased the thermal conductivity of the original glass by ∼50% and the new glass still exhibited optical transparency. Such MgO-dispersed glass could be successfully used in thermal management applications requiring both transparency and formability. [ABSTRACT FROM AUTHOR]

We investigated the Pockels effect in polycrystalline materials consisting of highly oriented polar fresnoite-type Sr2TiSi2O8 fabricated using perfectly surface-crystallized glass-ceramics (PSCGCs). The chemical composition of the precursor glass was shown to significantly affect the crystallized texture, e.g., the crystal orientation and appearance of amorphous nanoparasites in the domains, resulting in variations in the Pockels constants. Single crystals exhibiting spontaneous polarization possessed large structural anisotropy, leading to a strong dependence of the nonlinearoptical properties on the direction of polarized light. This study suggests that variations in the Pockels constants (r13 and r33) and tuning of the r13/r33 ratio can be realized in PSC-GC materials. [ABSTRACT FROM AUTHOR]

We have synthesized spinon thermal conductivity materials in Sr- Cu- O system by glass-ceramics technique. The materials are promising for active control of thermal energy in microelectronic devices because of high and anisotropic thermal conduction, its controllability, and electric insulation. Nevertheless, research on these materials has been limited to that concerning theoretical perspectives and investigation of physical properties using large single crystals. In this study, we adopt glass-ceramics technique to synthesize these materials: We prepared melt-quenched multicomponent oxides including SrO and CuO, and checked its glass-forming ability and crystallization behaviors by heating. As a result, we have found that SrCuO2 and Sr14 Cu24 O41, known as the spinon thermal conductivity materials, are synthesized using SrO- CuO-- Li2 O-- Al2 O3-- Ga2 O3 system. This synthesis process for the system will provide practical application of the spinon thermal conductivity materials. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Silicate glass has been used for long time because of its advantages from material's viewpoint. In this paper, we report the observation of Pockels effect by Mach-Zehnder interferometer in polycrystalline ceramics made from a ternary silicate glass via crystallization due to heat-treatment, i.e., glass-ceramics. Since the silicate system is employed as the precursor, merits of glass material are fully utilized to fabricate the optical device component, in addition to that of functional crystalline material, leading us to provide an electro-optic device, which is introducible into glass-fiber network. [ABSTRACT FROM AUTHOR]

Atomic bonding structures in xGeO2–(100-x)GeS2 glasses have been studied through structural and chemical experiments. Atomic force microscope images in alkali-etched samples with x = 80 mol % show nano-scale dips, which are ascribable to isolated GeS2 clusters. Transmission electron microscope images and small angle X-ray scattering patterns suggest that the glass with x ≈50 has pronounced heterogeneous structures in nanoscales. Composition dependence of an etching rate exhibits a characteristic change at x = 60, which can be interpreted as a percolation threshold of tetrahedral GeS4 units. These results support a nanostructure model for the oxy-chalcogenide glass. [ABSTRACT FROM AUTHOR]

Photoluminescence and electron-spin resonance in nano-structured GeO2–GeS2 glasses have been studied. With an increase in the GeO2 content from 0 to 80 mol %, a luminescence peak blue-shifts from 1.3 to 2.1 eV in photon energy, which is more prominent than an increase in the optical gap from 3.4 to 3.6 eV. Dark and photoinduced electron-spin signals become maximal at around an intermediate composition 50GeO2–50GeS2. It is difficult to interpret these composition variations using the charged defect model proposed for chalcogenide glasses. [ABSTRACT FROM AUTHOR]