Search

A plastic plate made of polycarbonate (PC) was functionalized as a water-repellent nature by unbalanced radio-frequency(rf) magnetron plasma sputtering using polytetrafluoroethylene target. In order to build the unbalanced rf magnetron plasma, 3D magnetic field analysis is simulated at three setups using ferrite, samarium cobalt and neodymium magnets so that the combination of ferrite and neodymium magnets is selected. A thin film is prepared on the PC plate at argon gas pressures of 2 and 50 Pa and rf input powers of 50, 100, 150 and 200 W. The functionalized PC surface has resulted in hydrophobic nature, that is, a water contact angle is higher than 90 degree, at all experimental conditions. It is found that the water contact angle is independent with rf power at approximately 108 degree at low pressure of 2 Pa, whereas it gradually increases with increasing rf power from 104 to 112 degree at high pressure of 50 Pa. These surfaces were analyzed by X-ray photoelectron spectroscopy (XPS) analysis. The ratio of F 1 s component to all components of C 1 s, O 1 s and F 1 s from XPS spectra for 2 Pa was higher than that for 50 Pa.

Microfluidic paper-based analytical devices (μPADs) have recently attracted the attention of researchers and industry owing to their various advantages. However, µPADs lack a way to control fluid flow; therefore, it is difficult to perform complex immunoassays that use multiple reagents and replace the reagents from the analytical area. We developed a controllable thermoresponsive valve for μPADs by functionalizing a polyvinylidene difluoride porous membrane with plasma-induced graft polymerization of poly(N-isopropylacrylamide) (PNIPAAm), which is a thermoresponsive polymer that changes its hydrophilic properties near the lower critical solution temperature (LCST; 32 °C). Surface analysis by attenuated total reflectance Fourier transform infrared spectroscopy confirmed that the fabricated thermoresponsive valves coated with PNIPAAm. The valve performance was evaluated by sandwiching the thermoresponsive valve between two paper microchannels stacked in a T-shaped paper microfluidic device. The thermoresponsive valve fabricated with a monomer concentration ranging from 2.3 to 3.0 wt% and a polymerization time of 5 h or 2.0 wt% and 20–22 h showed good valve performances. These valves were able to stop the flow at room temperature, and allow the flow by opening within 20 s after heating was initiated using a Peltier element located just under the valve. The valve was successfully closed, thereby stopping the flow, and opened by heating. Although a detailed evaluation of the fluid behavior is necessary, we have demonstrated that our thermoresponsive valve can be opened and closed reversibly by temperature control. We believe that this thermoresponsive valve could potentially be used to control the flow of multiple reagents in µPADs.

Non-destructive testing of carbon-fiber-reinforced plastic (CFRP) laminates with bidirectional fiber bundles (twill-weave) using a mechanoluminescence (ML) technique was proposed. The dynamic strain distributions and fracture phenomena of the CFRP laminates in the tensile testing were evaluated by the fabricated ML sensor consisting of SrAl

Hydrofluoric acid has been used to remove salivary contamination in dental glass-ceramics before bonding treatment. However, alternative methods are required because hydrofluoric acid is harmful. This study examined the cleaning effects of phosphoric acid and sodium hydroxide on glass-ceramics for bonding pre-treatment.Feldspar porcelain was divided into four groups: (C) cleaned porcelain without any contamination, (S) porcelain contaminated with saliva, (SPA) porcelain cleaned with 37% phosphoric acid after saliva contamination, and (SSH) porcelain cleaned with 10% sodium hydroxide after saliva contamination. Each sample was bonded to the resin cement using a silane-containing primer. They were then subjected to a shear bond strength (SBS) test. Each surface was analyzed by scanning electron microscopy (SEM), contact angle measurements, and Fourier transform infrared spectroscopy (FT-IR).The SBS of group SSH was comparable to that of group C but significantly higher than that of groups S and SPA. SEM observations showed that saliva-like structures remained on the samples of groups S and SPA, but not on the SSH group. The contact angles of groups C and SSH were comparable and significantly smaller than those of groups S and SPA, respectively. FT-IR analysis also revealed saliva in groups S and SPA, which was absent in the SSH group.The saliva remained on the porcelain even after cleaning with phosphoric acid, and SBS was not restored to the same level as before the contamination. In contrast, sodium hydroxide eliminated saliva and restored SBS to the same level as before contamination.

Mechanoluminescence (ML) material starts receiving attention as two-dimensionally visualizing physical phenomena such as strain, stress, or load. This paper focused on the synthesis of ML materials with multi-elements using an organic acid-aided method and the optical properties of ML materials such as SrAl2O4 doped with Eu2+, Eu2++Cr3+, Eu2++Nd3+, or Eu2++Cr3++Nd3+ ions, which emit multi-wavelength luminescence including visible, NIR, and SWIR ranges. From the characterizations of the synthesized materials, we conclude that the organic acid-aided method can synthesize even the complex ML material including multi-elements. Moreover, The SrAl2O4 doped with Eu2+, Cr3+, and Nd3+ ions showed the highest ML intensity in the wavelength range of 750 – 1000 nm compared to the other synthesized ML materials, although there was almost no difference in the crystal structure and particle morphology.

Significance This study is the first to show that the manual upper eyelid elevation (manual UEE) that is commonly used to prevent disruption of the IOP measurement due to blinking or upper eyelid contact with the tip of the tonometer does not affect the IOP values. Purpose We investigated whether manual UEE affects the IOP readings using three rebound tonometers (Icare TA01i, Icare PRO, and Icare ic100) and Goldmann applanation tonometry (GAT). Methods One eye was measured for 101 patients (56 eyes of primary open-angle glaucoma patients and 45 healthy subjects). The IOPs were measured without and with manual UEE. Each IOP was measured twice; the measurement order using the tonometers was randomly selected. In addition, palpebral fissure height (distance between the upper and lower eyelids) was measured. Results The IOPs without manual UEE were 12.1 ± 2.9, 13.3 ± 2.7, 11.7 ± 2.9, and 16.0 ± 3.2 mmHg (Icare TA01i, Icare PRO, Icare ic100, and GAT), and those with manual UEE were 12.3 ± 3.0, 13.3 ± 2.8, 11.7 ± 2.9, and 16.0 ± 3.3, respectively. No significant difference was found between the IOP without and with manual UEE (IOP difference; all, P > .50; paired t test). Multiple linear regression analyses revealed that palpebral fissure height did not affect IOP difference for any of the tonometers. Conclusions Simple manual UEE when measuring the IOP has little effect on the IOP obtained using all current rebound tonometers and GAT.

Purpose: To investigate iris morphological features in 360° angle-closure neovascular glaucoma (NVG) by swept-source anterior segment optical coherence tomography (ASOCT). Patients and Methods: In this retrospective, clinic-based, comparative study, 14 patients with 360° angle-closure NVG and 14 healthy age-matched control subjects were enrolled. All patients enrolled had no prior glaucoma surgery but underwent cataract surgery with intraocular lens implantation. Horizontal scanning images of swept-source ASOCT were analyzed using software calipers in temporal and nasal angle areas. The iris thickness at 1 and 2 mm from the pupil edge, iris length, trabecular meshwork length, peripheral anterior synechia (PAS) length, PAS height ratio (PAS length/trabecular meshwork length), and pupil diameter were measured. Results: Between the groups, there were no statistically significant differences in iris length, trabecular meshwork length, and pupil diameter (p > 0.05). However, the iris thickness was significantly reduced in the NVG group compared with the control group in the temporal and nasal areas (0.306 vs. 0.563 mm/0.326 vs. 0.645 mm at 1 mm, 0.278 vs. 0.523 mm/0.282 vs. 0.546 mm at 2 mm, respectively) (mean, all p < 0.001). In the NVG group, PAS height ratios were 1.55 ± 0.45 (mean ± standard deviation) (range, 0.58–2.30) and 1.55 ± 0.78 (range, 0.68–3.68) at the temporal and nasal angles, respectively. Conclusions: In patients with 360° angle-closure NVG, the iris thickness decreased to about 50% of that in healthy subjects, and the PAS length exceeded the trabecular meshwork length by about 1.5 times.

The aim of this paper is to study changes in the Ag-Pd-Cu-Au alloy surfaces by alumina air-abrasion process and effect of those changes on the adhesive bonding characteristic. Surface roughness, surface composition and chemical state of the alumina air-abraded alloys were analyzed by a confocal laser scanning microscope, an energy dispersive X-ray spectroscopy and an X-ray photoelectron spectroscopy. The results showed that the alumina air-abrasion changed the alloy surface by mechanical roughening, alumina remain and copper oxidation. Effect of the changes in the alloy surface on the adhesive bonding characteristic was examined by using a methyl methacrylate/tri-n-butylborane derivative (MMA/TBB) resin cement with the 10-methacryloyloxydecyl dihydrogen phosphate (MDP) contained primer. The shear bond strength test results indicated that the surface oxidation by the abrasion is the main contributor that improved the adhesive bonding rather than other effects such as mechanical roughening or alumina remain.

Here, a mechanoluminescence-assisted double cantilever beam (DCB) test was proposed and its effectiveness was demonstrated. Based on mechanoluminescence, a crack tip was clearly distinguished and s...

We applied mechanoluminescence (ML) sensor, which is a polymer composite film made of a ML material (europium doped strontium aluminate, SrAl2O4:Eu) and epoxy resin, to evaluate relative strain distribution of carbon fiber reinforced plastics (CFRPs) laminates with bidirectional fiber bundles (twill weave). It was found that the ML sensor attached to the twill-woven CFRP laminate exhibited a distinctive ML pattern in a tensile testing, and the ML pattern was similar to the twill pattern. As a result of analysis of the obtained ML images, the higher ML intensity areas were found to be a longitudinal fiber bundles (tensile direction) and the lower ML intensity areas were the transverse fiber bundles. Based on the results of this study, it is concluded that the ML sensor can experimentally visualize the non-uniform mechanical behavior of the twill-woven CFRP laminates in the tensile testing.

Elasticoluminescent material is a novel ML functional ceramic powder (controllable size: 10 nm―100 μm, representative and the most efficient ML material: SrAl2O4:Eu2+) and it can emit intensive light repeatedly accompanied by mechanical stress such as deformation, friction, impact, even in elastic deformation region. The ML intensity is proportional to strain energy of the material. Thus, when dispersedly coated onto a structure, each particle acts as a sensitive mechanical sensor, while the two-dimensional (2D) emission pattern of the whole assembly reflects the dynamical strain/stress distribution inside the structure and the mechanical information around the defect and crack or the in-visible tip. This ML visualization technique provides a novel way of diagnosing the structural health, especially in early detection for safe & security measure. Actually, the ML sensor has been applied to real social infra-structure such as bridge, building, welding point of pipeline and high pressure vessel, and successfully demonstrated the ability to detect active crack including likelihood for growth, real crack propagation and mechanically weak points etc. Meanwhile, recently NEW advanced material such as CFRP, high tensile strengthen steel and non-steel metal for light weight vehicle are strongly required from the viewpoint of energy saving and environment. Accordingly, joint & adhesive technologies especially for different kinds of materials and the non-destructive evaluation have been investigating for application of these materials and the reliability in use. Especially, as to adhesion, kissing bond and weak bond, in which strengthen of the bonding is nothing or weak respectively without void and crack, have been remaining as challenge for the application and has been vigorously investigated in the field of non-destruct evaluation so far. In the presentation, we would like to report on suitability of the ML sensing for diagnosing (1) a stress distribution in adhesive, (2) visualization of mechanical distribution related to adhesive condition. In fact, as the result of (1), we succeeded to directly visualize stress distribution in adhesive for the first time through mechanoluminescence. We will discuss the results with the result of conventional FEM analysis, simulation of mechanical stress distribution. In addition, as the result of (2), we succeeded to visualize strass/strain distribution of adherend, clearly find out the stress/strain distribution are related to adhesion condition and also find out the area of pseud kissing bond through mechanoluminescence for the first time. [Acknowledgement] The research was partially supported by Innovative Structural Materials Association (ISMA), program for the promotion of scientific research with a view to creating intellectual resources through New Energy and Industrial Technology Development Organization (NEDO), AIST Strategic budget 2015 and KAKENHI, Grant-in-Aid for Scientific Research (B).

The goal of this study was to investigate the chemical alteration of a dental alloy surface by alumina air-abrasion and its effect on bonding to resin cement. Alumina air-abrasion was carried out on an Ag-Pd-Cu-Au alloy. The surface morphology and chemical state of the abraded alloy were characterized. The effect of the air-abrasion on the shear bond strength between the alloy and a methyl methacrylate/tri-n-butyl borane (MMA/TBB) resin cement with some primers was evaluated. The surface characterization revealed that the alumina air-abrasion mechanically roughened and chemically altered the surface. The chemical alterations had two effects: (1) abraded alumina particles remained on the alloy surface and (2) copper ions were oxidized in the alloy surface. As the result, the shear bond strength test indicated that 10-methacryloyloxydecyl dihydrogen phosphate (MDP) contained primer worked with the abraded alloy surface, whereas it did not work with the non-abraded alloy surface.

We evaluated the agreement between the intraocular pressure (IOP) values of new rebound tonometer, Icare ic100, and Icare TA01i or Goldmann applanation tonometer (GAT).We studied one eye each of 106 subjects (57 with primary open-angle glaucoma, 49 healthy subjects). IOP was randomly measured twice with the patient in sitting position using the Icare ic100, Icare TA01i, and GAT. Tonometer measurements were evaluated using Bland-Altman analysis. The relationship between IOP difference (Icare ic100-GAT) and age, sex, disease, axial length, central corneal thickness (CCT), and corneal curvature was investigated using multivariate regression analysis.IOPs measured using Icare ic100, Icare TA01i, and GAT were 11.7±3.0 (mean±standard deviation), 12.2±2.9, and 16.0±3.2 mm Hg, respectively (P0.001, one-way analysis of variance). Icare ic100 showed significantly lower IOPs than GAT (P0.05), but not than Icare TA01 (P0.05; Tukey-Kramer test). Bland-Altman analysis revealed that the mean differences between Icare ic100 and Icare TA01i and those between Icare ic100 and GAT were -0.46 and -4.2 mm Hg, respectively (95% limits of agreement, -3.35 to 2.42 and -10.10 to 1.61 mm Hg, respectively). For IOP differences between Icare ic100 and GAT, parameters selected in the optimal model were CCT (coefficient, 20.3, P=0.029), corneal curvature (3.0, P=0.020), and glaucoma-normal (-1.0, P=0.004).The new rebound tonometer Icare ic100 almost constantly showed IOPs lower than GAT. The difference was affected by CCT, corneal curvature, and disease.

Elderly people generally tend to behave slowly and the reaction time is delayed; moreover, not many are familiar with mechanical or electronic controls. Therefore, when designing and developing a standing and sitting assist device for the elderly, an easy-to-learn and simple-to-use interface system capable of responding to complex and diverse environments is of particular importance. Since the assist device is expected to employ in various kinds of public places, more than anything, protection of personal information is its fundamental requirements. For this purpose, our paper tackles a problem of designing a user interface between an elderly user and the assist device helping him/her stand up and sit down. As a solution approach, the paper introduces a one-dimensional distance-based interface, allowing to recognize the 3D standing and/or sitting behaviors, without requiring any additional sensor inputs such as visual data.

Near-infrared-mechanoluminescence (NIR-ML) intensity of monoclinic SrAl2O4 doped with Eu2+ ion (SrAl2O4:Eu) ML material was tuned by the addition of other metal ions (Cr3+, Nd3+ or both metal ions) into the SrAl2O4 matrix through an organic acid-aided process. This paper especially focused on the synthesis of ML materials with multi-metal elements utilizing an organic acid-aided method and the optical properties of the ML materials such as SrAl2O4 doped with Eu2+, Eu2+ + Cr3+, Eu2+ + Nd3+, or Eu2+ + Cr3+ + Nd3+ ions aiming at the expression of multi-wavelength luminescence including visible (0.4–0.7 μm) and NIR (0.7–2.5 μm) wavelength ranges. From characterizations of the synthesized materials, we found that the organic acid-aided method could synthesize even the ML material with complicated multi-metal element composition. Moreover, the SrAl2O4 doped with Eu2+, Cr3+, and Nd3+ ions gave the highest ML intensity in the wavelength range of 750–1000 nm compared to the other synthesized ML materials, although there was almost no difference in the crystal structure and particle morphology. Correlations between photoluminescence intensity and the additive metal elements into the SrAl2O4:Eu were suggestive that the NIR-ML intensity was produced by the energy transfer from Eu2+ ion to Cr3+ and Nd3+ ions based on an energy transfer mechanism.

The influence of the nitrogen gas ratio on the gallium nitride (GaN) film growth has been investigated using a high-density convergent plasma sputtering device at room temperature. To obtain a highly reactive environment for GaN film growth, the convergent magnetic field lines assist the high-density plasma transport near the target surface. An orthogonal array in the design of experiments was used to effectively investigate GaN film growth conditions. To optimize the GaN film growth conditions, we focus on four sputtering parameters: (1) the N 2 gas flow ratio, (2) the inflowing ion current to the target, (3) the process gas pressure, and (4) the target-substrate distance. The N 2 gas flow ratio mainly characterizes the growth condition of c-axis oriented wurtzite-structure GaN films on an unheated glass substrate. The full width at half maximum of the rocking curve for the GaN(0002) peak position decreases to 3.9 ° in the growth condition with 100% nitrogen at room temperature.

A mechanoluminescence (ML) material is a kind of phosphor. There has been attracting attention as a sensing material capable of two-dimensionally visualizing physical phenomena such as strain, stress, or load [1-5]. In particular, the ML material that emits near-infrared (NIR:0.75~1.0 μm) and short-wave infrared (SWIR:1.0~2.5 μm) luminescence has biological transparency and a wavelength range different from a room illumination and is expected to spread a new applying field [6-7]. To use the ML material for physical sensing technology using an inorganic-organic hybrid film mixed with resin, the diameter of the ML particle needs to be several micrometers or less. However, the ML material is commonly synthesized by a solid-state reaction method at a rather high temperature above 1400°C, resulting in the formation of large particle size. Such a large ML particle is pulverized under a mechanically milling process to reduce the particle size, producing crystal defects. The crystal defects are known to be one of the causes of the charge career trapped sites in the ML material, posing deterioration of the ML intensity as well as a decrease in the reproducibility of sensing characteristics. Thus, to develop an ML material having a high ML intensity, it is necessary to establish a synthetic method capable of lowering the sintering temperature. For a decrease in the sintering temperature of the functional oxides, it has been reported that it is effective to produce a precursor whose particle size and shape are controlled by a solution technique. Although there have been numerous reports regarding the solution technique, an organic acid-aided method is suitable for producing a complicated material with a multi-element composition because it desolvates an aqueous solution and remains all the metal compounds [8]. In the present study, therefore, we tried to synthesize ML material by using the organic acid-aided method and evaluated both optical properties under visible light and near-infrared regions. Among various ML materials reported, we selected SrAl2O4 co-doped with Eu, Cr, and Nd ions (SAOEuCrNd) which emits both NIR and SWIR luminescence [7] and selected malic acid as a representative organic acid. For comparison, SrAl2O4 doped with Eu (SAOEu), SrAl2O4 co-doped with Eu,Cr (SAOEuCr), or Eu,Nd (SAOEuNd) were also synthesized by using the same synthetic method. The synthesized ML materials were evaluated by various analysis instruments. From x-ray diffraction (XRD) patterns of the synthesized ML materials, all the diffraction peaks coincided with those of the monoclinic SrAl2O4 (PDF no. 34-0379). This indicates that monoclinic SrAl2O4 can be synthesized by the organic acid-aided method even by using various luminescent center ions. The photoluminescence (PL) spectra of all the synthesized ML materials exhibited a broad emission which is centered at approximately 520 nm under excitation at 365 nm. On the other hand, Nd-doped ML materials such as SAOEuNd and SAOEuCrNd showed several peaks at around 900, 1100, and 1400 nm under excitation at 365 nm. The PL intensities under NIR and SWIR regions for SAOEuCrNd were much higher than those for SAOEuNd. Logically, it is reasonable to expect that Cr ion behaved as a sensitizer such as an energy transfer mechanism of YAG:Cr,Nd. Finally, we evaluated the ML intensity under NIR and SWIR regions for the synthesized ML materials by using a lab-built system comprising Si image sensor and optical filter (pass long wavelengths >750 nm). As a result, Nd-doped ML materials showed ML response toward the tensile strain and the ML intensity increased with increasing the tensile strain, although there is no luminescence response toward the tensile strain for SAOEu. Especially, SAOEuCrNd exhibited the highest ML intensity. Thus, the SAOEuCrNd synthesized by the organic acid-aided method using metal nitrates and malic acid is a promising candidate for ML materials which emits both NIR and SWIR luminescence. [1] C.N. Xu, T. Watanabe, M. Akiyama, X.G. Zheng, Appl. Phys. Lett., 74(9), 1236 (1999). [2] C.N. Xu, T. Watanabe, M. Akiyama, X.G. Zheng, Appl. Phys. Lett., 74(17), 2414 (1999). [3] A. Yoshida, L. Liu, D. Tu, S. Kainuma, C.N. Xu, J. Disaster Res., 12, 506 (2017). [4] N. Terasaki, Y. Fujio, S. Horiuchi, and H. Akiyama, Int. J. Adhes. Adhes., 93, 40 (2019). [5] Y. Fujio, C. N. Xu, Y. Sakata, N. Ueno, N. Terasaki, J. Alloys Compd., 41, 154900 (2020). [6] D. Tu, C.N. Xu, S. Kamimura, Y. Horibe, H. Oshiro, L. Zhang, Y. Ishii, K. Hyodo, G. Marriott, N. Ueno, X.G. Zheng, Adv. Mater., 1908083 (2020). [7] N. Terasaki, C.N. Xu, WO 2015033648, September 9, 2013. [8] Y. Teraoka, H. Kakebayashi, I. Moriguchi, S. Kagawa, Chem. Lett., 20(4), 673 (1991).

A new non-destructive evaluation technique to detect cracks emanating from the inner surface (inner cracks) of a high-pressure hydrogen storage cylinder was developed by means of mechanoluminescence (ML) sensor consisting of SrAl2O4:Eu ML material and epoxy resin. To visualize the inner crack, a sheet ML sensor was attached onto the outer surface of the storage cylinder subjected to hydraulic pressure cycling with the maximum pressure of 45 MPa. The ML pattern was changed with an increase in the cycle number and the ML sensor could visualize the inner crack. The stress analysis by the finite element method clarified that the ML sensor provided unique equivalent strain distribution associated with stress concentration at the crack tip, i.e. the distance between two points having high equivalent strains was inversely proportional to the crack depth; consequently, the growth behavior of the inner crack was non-destructively quantified with the ML sensor attached on the outer surface.

We experimentally demonstrated the depth analysis of artificial invisible notches on the backside of aluminum alloy (A6061-T6) plate using a high-sensitive mechanoluminescence (ML) film. The ML film was developed by a screen-printing method utilizing a mixture of Eu-doped SrAl2O4 powder and optical epoxy resin. From the analysis of luminescence distribution images (ML patterns) obtained from the ML film attached to the aluminum alloy specimen, the ML film visualized the notches of 37.5–100% depth levels from the opposite side of the notched surface of the specimen under dynamic tensile testing. Moreover, it was clarified that the discovered two parameters from the ML patterns are worthwhile to estimate the depth level of the invisible notch. The first parameter is the ratio of the time derivative of the ML intensity curves located on the stress concentration area and nominal stress area. The other is the distance between two points with maximum ML intensity located around the back-side of the invisible notch. These parameters were found to vary almost linearly with the depth level of the back-side notch, although their detection ranges are different. Also, it should be noted that the second parameter is hardly affected by the strain magnitude and its rate. This implies that the high-sensitive ML film is a promising candidate as non-destructive testing to predict a residual life of a fatigue crack in a structure under dynamic behavior.

Low-temperature aluminum nitride (AlN) depositions were studied under low gas pressure conditions of 0.1 Pa. In order to operate under 0.1 Pa sputter-conditions, the magnetic mirror-type magnetron cathode (M3C) has been developed in the authors' studies. The plasma light-emission distributions generated by the M3C were observed at an input RF power of 5–100 W and an Ar gas pressure of 0.1–0.65 Pa. The M3C can operate effectively with both low gas pressure of 0.1 Pa (Ar) and low RF power of 5 W. The AlN films were deposited using a bare silicon substrate without external substrate heating. The c-axis oriented AlN film was obtained at 0.1 Pa (pure nitrogen), 100 W, and a target-to-substrate distance of 70 mm.

This study aims to develop a corona discharge process for a surface treating a glass-ceramic, feldspar porcelain, to improve its bonding to a resin cement with a silane-coupling agent. Corona discharge, a type of plasma process, was performed using a custom-made device on a porcelain surface at temperatures ranging from 25 to 300 °C, for specific treatment times in air. The porcelain was then subjected to a post-heat-treatment at 600 °C to condition the surface state. The resulting surface was primed with a silane-coupling-agent followed by cementing using a resin cement to measure the shear bond strength (SBS). To investigate the effect of surface modifications by the corona discharge treatment, the porcelain was characterized by surface roughness, contact angle, and an X-ray photoelectron spectroscopy analyses. The SBS for the corona-discharge-treated porcelain increased with an increase in treatment-temperature and -time, and reached the maximum value at 200 °C and 5 min. The post-heat-treatment improved the bond durability after thermocycling. The SBS for the corona-discharge-treated porcelain was then compared to that of a conventional hydrofluoric-acid-treated one, which showed that the SBSs were comparable. The results of the surface characterizations indicated that the corona discharge treatment generated silanol groups on the porcelain surface giving hydrophilic properties without roughening the surface. It was found that the corona discharge treatment generates silanol groups on the porcelain surface, resulting in an increased SBS. This study is the first to demonstrate that corona discharge treatment is effective for improving bond strength through the modification of the surface of glass-ceramics.

A selective carbon monoxide (CO) sensor was developed by the use of both of CuCrFeO4 and CoCrFeO4 as the sensing electrode (SE) for yttria-stabilized zirconia (YSZ)-based potentiometric sensor. The sensing-characteristic examinations of the YSZ-based sensors using each of spinel oxides as the single-SE sensor showed that CuCrFeO4-SE had the ability to detect CO, hydrocarbons and NOx gases, while CoCrFeO4-SE was sensitive to hydrocarbons and NOx gases. Thus, when both SEs were paired as a combined-SEs sensor, the resulting sensor could generate a selective response to CO at 450 °C under humid conditions. The sensor was also capable of detecting CO in the concentration range of 20–700 ppm. Its sensing mechanism that was examined via polarization-curve measurements was confirmed to be based on mixed-potential model. The CO response generated by the combined-SEs sensor was unaffected by the change of water vapor concentration in the range of 1.3–11.5 vol% H2O. Additionally, the sensing performance was stable during 13 days tested.

The sensing characteristics of a yttria-stabilized zirconia (YSZ)-based sensor using a sensing electrode (SE) consisting of rod-shaped TiO2 added with 1 wt.% of nano-sized Pd particles (abbreviated as TiO2(+ Pd)-SE) were evaluated, aiming at selective detection of hydrocarbons. The rod-shaped TiO2-SE without Pd addition (TiO2-SE) was found to give high sensitivities to both C3H8 and C3H6 which were used as representatives of alkane and alkene groups, respectively, in hydrocarbons (HCs), while TiO2(+ Pd)-SE gave selective detection of C3H8. The evaluation of catalytic activity to the gas-phase oxidation of HCs for the SE materials revealed that the oxidation of C3H6 was largely promoted by the Pd addition, leading to the high selectivity to C3H8 for the sensor using TiO2(+ Pd)-SE. From the results of polarization-curve measurements, the current value for the cathodic reaction of O2 was found to be slightly decreased by the Pd addition, while those for the anodic reaction of C3H8 and C3H6 were largely decreased. This is presumably due to the decrease in the actual concentration of C3H8 and C3H6 at the SE/YSZ interface owing to the promoted gas-phase oxidation of these HCs through the TiO2(+ Pd)-SE layer. XRD measurements as well as SEM observations confirmed that the added Pd particles were existing as PdO particles on the surface of the rutile-type TiO2 rods after the SE fabrication process. The stability test revealed that the C3H8 sensitivity of the sensor using TiO2(+ Pd)-SE gradually increased and reached the stable value after the 12 day operation. By considering the results of the complex-impedance analysis, we believed that this gradual increase in sensitivity was due to the decrease in the catalytic activity against the gas-phase oxidation of C3H8 in the TiO2(+ Pd)-SE layer.

The influence of an organic solvent treatment on elasticoluminescent (ELS) characteristics of mechanoluminescent (ML) sensor using the composite film consisting of an ELS material and epoxy resin was investigated. We used strontium aluminate doped with a small amount of europium (SrAl 2 O 4 :Eu, SAOE) as an ELS material in this study. After evaluating the ELS characteristics of the fabricated ML sensors using SAOE treated with/without various organic solvents, SAOE treated with methanol and ethanol showed lower ELS intensities than that of untreated SAOE. In contrast, the ELS response curves against strain for the ML sensors using SAOE treated with acetone and toluene, overlapped with that of untreated SAOE. From the characterization of SAOE treated with alcohols, such as methanol and ethanol, we can hypothesize that poor ELS characteristics is due to the degradation of the SAOE grain surfaces by the hydrolyze reaction of SAOE with hydroxyl group of alcohol. Thus, on the basis of the obtained results, we can conclude that the selection of organic solvent used in the preparation of SAOE film is of considerable importance in the development of ML sensor with a highly-reliable ELS characteristic.

We investigated the detailed time course of conjunctival hyperemia induced by ripasudil 0.4%, a novel Rho-kinase inhibitor anti-glaucoma eye drop, in healthy subjects.We recruited 51 healthy subjects and administered ripasudil 0.4% in their right eye. We evaluated conjunctival hyperemia using slit lamp photography and measured the intraocular pressure (IOP) using the Icare PRO Rebound Tonometer at baseline and after 5, 15, 30, 60, 90, and 120 min. The conjunctival hyperemia score was graded by three independent observers on a scale of 0 (none) to 3 (severe). Additionally, we analyzed the "percent coverage" of conjunctival hyperemia by using an automated hyperemia analysis software program; this program provides the pixel coverage of the conjunctival vessels in the region of interest. Dunnett and Steel multiple comparison tests were used, as appropriate, for the subsequent analyses.The conjunctival hyperemia score and percent coverage increased rapidly after the instillation of ripasudil 0.4%, peaking at 15 min (score: 1.83 ± 0.29 [mean ± SD]) and 5 min (11.6% ± 4.7%), respectively, and then gradually decreasing until 120 min (0.45 ± 0.22 and 4.7% ± 1.8%, respectively), when they reached a level that was not significantly different from the baseline values. The IOP decreased significantly compared to the baseline at 30, 60, and 90 min, based on the Dunnett test.Conjunctival hyperemia induced by ripasudil 0.4% peaks rapidly to moderate severity, but subsides relatively quickly.

Mechanoluminescent (ML) studies were investigated for double cantilever beam (DCB) and tapered-DCB (TDCB) tests, and the following information was recorded. (1) The ML behavior on the top surface of the adherend perfectly synchronizes the shape of the failure front at the bond line. Thus, ML sensing can be utilized as a monitoring indicator of the behavior and fracture toughness at a crack frontline from outside the adherend. (2) The failure front of a DCB specimen under dissimilar material bonding, consisting of CFRP and CFRTP in particular, can be visualized and considered as a winding line. (3) The failure process zone (FPZ) on the bond line for DCB and TDCB specimens was successfully visualized based on the mechanoluminescence, and the area of the TDCB specimen was determined to be much longer than that of the DCB specimen.

A highly selective hydrogen (H2) sensor has been successfully developed by using an yttria-stabilized zirconia (YSZ)-based mixed-potential-type sensor utilizing SnO2 (+30 wt.% YSZ) sensing electrode (SE) with an intermediate Al2O3 barrier layer which was coated with a catalyst layer of Cr2O3. The sensor utilizing SnO2 (+30 wt.% YSZ)-SE was found to be capable of detecting H2 and propene (C3H6) sensitively at 550 °C. In order to enhance the selectivity towards H2, a selective C3H6 oxidation catalyst was employed to minimize unwanted responses caused by interfering gases. Among the examined metal oxides, Cr2O3 facilitated the selective oxidation of C3H6. However, the addition or lamination of Cr2O3 to SnO2 (+30 wt.% YSZ)-SE was found to diminish the sensing responses to all examined gases. Therefore, an intermediate layer of Al2O3 was sandwiched between the SE layer and the catalyst layer to prevent the penetration of Cr2O3 particles into the SE layer. The sensor using SnO2 (+30 wt.% YSZ)-SE coated with a catalyst layer of Cr2O3 as well as an intermediate layer of Al2O3 exhibited a sensitive response toward H2, with only minor responses toward other examined gases at 550 °C under humid conditions (21 vol.% O2 and 1.35 vol.% H2O in N2 balance). A linear relationship was observed between sensitivity and H2 concentration in the range of 20–800 ppm on a logarithmic scale. The results of sensing performance evaluation and polarization curve measurements indicate that the sensing mechanism is based on the mixed-potential model.

We investigated the ease of use and accuracy of a new self/home-tonometer (IcareHOME) versus Goldmann applanation tonometry (GAT) and the Icare tonometer (Icare) by measuring the diurnal intraocular pressure (IOP).The right eyes of 43 healthy young subjects were studied. The IOP was measured using the IcareHOME, GAT, and Icare 6 times a day, every 2 hours, from 8:00 to 18:00. The coincidence of the diurnal curves among all tonometers was analyzed using a linear mixed model. The intradevice and interdevice agreement was evaluated using the intraclass correlation coefficients (ICC) and Bland-Altman method. The subjects' perception of the IcareHOME was evaluated using a questionnaire.The liner mixed model showed similar diurnal IOP curves for all tonometers (P=0.543); however, significant differences were observed between the tonometers over time (P0.001). The intradevice repeatability was ICC0.8 among all tonometers, although the interdevice agreement was lowest between the IcareHOME and GAT (ICC=0.641). The IOP values were significantly lower for the IcareHOME than for the GAT at 12:00, 16:00, and 18:00 (P0.05, Tukey-Kramer test). The mean differences between the Icare and IcareHOME and GAT and IcareHOME were 0.83 and 1.03 mm Hg, respectively (95% limit of agreement: -4.17 to 5.84 mm Hg and -3.91 to 5.98 mm Hg, respectively). Regarding the subjects' perception of handling the IcareHOME, 17 (39.5%) subjects answered "easy to use," 20 (46.5%) answered "normal," and six (13.9%) answered "difficult to use."The IcareHOME can be used as a self/home-tonometer; however, it may result in lower IOP values.

A selective and sensitive hydrogen (H 2 ) sensor capable of working at a high operating temperature was developed by using a pair of metal-oxide-based SEs formed on a yttria-stabilized zirconia (YSZ) tube, operating as a mixed-potential type sensor. The utilization of SnO 2 (+30 wt.% YSZ) electrode together with NiO-TiO 2 electrode configured as a combined-type sensor, successfully diminished the response of the examined interfering gases (especially propene), while maintaining high response toward H 2 at an operating temperature of 600 °C under humid operating conditions. The developed sensor exhibited quick response to 100 ppm H 2 , as the 90% response time was observed to be 9 s. The sensing performance of the combined-type sensor was barely affected by changes in water vapor concentration within the range of 1–4 vol.%, suggesting the resilience of the sensor to function in realistic working conditions. This sensor exhibited a linear relationship between sensitivity and H 2 concentration on a logarithmic scale.

The carbon monoxide (CO) sensitivity of a mixed-potential-type yttria-stabilized zirconia (YSZ)-based tubular-type sensor utilizing a ZnCr(2)O(4) sensing electrode (SE) was tuned by the addition of different precious metal nanoparticles (Ag, Au, Ir, Pd, Pt, Ru and Rh; 1 wt % each) into the sensing layer. After measuring the electromotive force (emf) response of the fabricated SEs to 100 ppm of CO against a Pt/air-reference electrode (RE), the ZnCr(2)O(4)-Au nanoparticle composite electrode (ZnCr(2)O(4)(+Au)-SE) was found to give the highest response to CO. A linear dependence on the logarithm of CO concentration in the range of 20-800 ppm at an operational temperature of 550 °C under humid conditions (5 vol % water vapor) was observed. From the characterization of the ZnCr(2)O(4)(+Au)-SE, we can conclude that the engineered high response toward CO originated from the specific properties of submicrometer sized Au particles, formed via the coalescence of nanosized Au particles located on ZnCr(2)O(4) grains, during the calcining process at 1100 °C for 2 h. These particles augmented the catalytic activities of the gas-phase CO oxidation reaction in the SE layer, as well as to the anodic reaction of CO at the interface; while suppressing the cathodic reaction of O(2) at the interface. In addition, the response of the ZnCr(2)O(4)(+Au)-SE sensor toward 100 ppm of CO gradually increased throughout the 10 days of operation, and plateaued for the remainder of the month that the sensor was examined. Correlations between SEM observations and the CO sensing characteristics of the present sensor were suggestive that the sensitivity was mostly affected by the morphology of the Au particles and their catalytic activities, which were in close proximity to the ZnCr(2)O(4) grains. Furthermore, by measuring the potential difference (emf) between the ZnCr(2)O(4)(+Au) and a ZnCr(2)O(4) electrode, sensitivities to typical exhaust component gases other than CO were found to be negligible at 550 °C.

A planar sensor using yttria-stabilized zirconia (YSZ) and each of NiO, Au and NiO/Au sensing-electrodes (SEs) was fabricated, and examined for detection of propene (C 3 H 6 ) at 600 °C. It was found that, while the sensor attached with NiO-SE showed minor response to several examined gases, the sensor using Au-SE gave selective and sensitive response to C 3 H 6 . However, the stability of the sensor using Au-SE was not satisfactory. Interestingly, the sensor attached with the NiO/Au (composite)-SE exhibited rather high sensitivity, selectivity and good stability to C 3 H 6 . In addition, the sensitivity (Δemf) of the sensor was found to be invariant to the change in water vapor concentration in the range of 2–11 vol% in the sample gas. Based on the results obtained from the SEM observation, the response stability was discussed briefly.

A stabilized zirconia-based sensor attached with an oxide sensing-electrode (SE) was developed for the selective detection of propylene (C3H6), representative hydrocarbon (HC), at high temperature. Among six kinds of commercial oxides examined, NiO-SE gave the highest sensitivity to C3H6 at 600°C under the wet condition. However, other sensing characteristics, such as the C3H6 selectivity, the response and recovery times, of this sensor were not satisfactory. Thus, to improve the C3H6 sensing characteristics, NiO-SE was successively mixed with different oxides. For better reproducibility of response, all the single- or mixed-oxide SEs were prepared by ball-milling. As a result, the sensor attached with NiTiO3-SE (the initial mixture of 50 mol% NiO and 50 mol% TiO2) exhibited highly selective and sensitive response to C3H6 at 650°C, accompanying with relatively quick response and recovery. In addition, by the comparison of sensing performances of NiTiO3-SEs fabricated by the different methods, the ball-milling method was found to be the most appropriate from the viewpoint of obtaining high selectivity and sensitivity to C3H6.

The mixed-potential-type yttria-stabilized zirconia (YSZ)-based planar sensors using nano-structured sensing-electrodes (SE) were fabricated and evaluated in the wide range of operating temperatures under the wet (5 vol.% water vapor) condition aiming at detection of exhaust gases and ammonia slip in automobiles. The sensors using nano-structured NiO-, laminated (NiO–Au)- or pure Au-SEs fabricated by r.f. sputtering gave the sensitive and selective responses to NO 2 at 600 °C. Furthermore, it was found that the fabrication method of Au-SE as well as the roughness of surface of YSZ solid electrolyte influenced to a large extent on the sensing characteristics of the fabricated sensors. The higher catalytic activity to electrochemical reaction of oxygen for the Au nano-particles fabricated by impregnation method resulted in the excellent sensitivity and selectivity to propene. The implementation of smooth YSZ substrates led to achieve the highly selective response to ammonia in the concentration range of 20–200 ppm. The detailed sensing characteristics and the proposed sensing mechanisms for the obtained sensors are discussed here.