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The use of hybrid operating rooms (HOR) for transcatheter aortic valve implantation (TAVI) has increased, so radiation exposure during procedures that use X-ray fluoroscopy is a fundamental problem not only for patients but also for surgeons and interventional cardiologists, increasing the risk of cataracts among operators. We investigated the efficacy of leaded glasses and protective sheets for ocular radiation protection.Methods and Results: Between January 2020 and February 2021 we enrolled 54 TAVI procedures using the transfemoral approach. The subjects were divided into a curtain protection group (Group C, n=20), glass protection group (Group G, n=17), and sheet protection group (Group S, n=17). The cumulative dose (CD) of the operators showed a decreasing trend in Group S compared with the other two groups. The CD normalized by dose area product (CD/DAP) of the operators was significantly reduced in Group S compared with Group C. However, Group G showed no significant difference compared with Group C. Regarding the distribution of CD/DAP, Group S had a significantly lower distribution than that in groups C and G.Protective sheets provide more stable radiation protection than conventional curtains or leaded glasses.

Although transcatheter aortic valve replacement (TAVR) has demonstrated favorable outcomes in randomized studies, there remains a sizable group of patients in whom TAVR may be futile. Characterizing the survival rate in a wide array of patients undergoing TAVR can help develop effective strategies for improving the allocation of medial resources.The aim of this study was to develop a risk model to estimate 1-year mortality after TAVR from a representative nationwide registry in Japan.The J-TVT (Japan Transcatheter Valve Therapies) registry contains complete data, including 1-year outcomes, on patients undergoing TAVR in Japan. A total of 17,655 patients underwent TAVR between 2013 and 2018. They were randomly divided into 2 groups in a 7:3 ratio to form a derivation cohort of 12,316 patients and a validation cohort of 5,339 patients. A risk model was constructed for 1-year mortality in the derivation cohort, and its discrimination and calibration were assessed in the validation cohort.The mean age of all registered patients was 84.4 years, and 68.8% were women. The mean body size area was 1.43 mA prediction model for 1-year survival following TAVR derived from a national clinical database performed well and should aid physicians managing TAVR patients.

Differences in guiding catheters (GCs) manipulations and selections among different access sites are currently unclear. We examined the differences in the routes of GCs for the left coronary artery (LCA) among the right radial, left radial, and femoral approaches. We used a combined angiography-computed tomography (CT) system that enabled to perform CT scans during percutaneous coronary intervention (PCI). We enrolled 88 patients who underwent CT scans during LCA PCI or percutaneous transluminal septal myocardial ablation. To evaluate the route of GCs, we analyzed the positions of the catheter’s contact point on the contralateral aortic wall to the LCA ostium, which were expressed by the angle formed by the vertical line and the diagonal line from the GC shaft to the center of the aorta. The procedures were performed via the right radial in 47 cases, left radial in 20, and femoral approach in 21. The positions of the catheter’s contact point were significantly different depending on the approaches (interquartile range − 3.7 [− 14.3 to 7.8], − 46.5 [− 76.9 to − 9.3], and − 30.7 [− 39.4 to − 22.4] degrees, respectively; p

Background Aortic root rupture is a severe complication of balloon-expandable transcatheter aortic valve replacement (TAVR). Although previous studies have revealed several risk factors for this complication, predicting this complication is occasionally difficult. Case summary A 78-year-old male patient underwent TAVR via a transfemoral approach using a 29-mm balloon-expandable valve. No recognized risk factors for aortic root rupture existed in pre-procedural multi-detector computed tomography (MDCT) analysis. However, after the valve deployment, sudden haemodynamic collapse occurred. Transoesophageal echocardiography revealed pericardial effusion, which led to an immediate diagnosis of cardiac tamponade following aortic root rupture. Following pericardial drainage via a subxiphoid approach, the haemodynamics were immediately stabilized. After 10 days of close observation, the patient was discharged on Day 39 without additional problems. He was still alive at the 6-month follow-up without sequelae. Discussion Established risk factors for aortic root rupture include >20% area oversizing, bicuspid aortic valve, small annulus (

We demonstrate a MOPA GaN system, a microring DFB laser coupled to another microring laser. Both rings lase in a single mode, establishing a building block towards a topological laser array in GaN.

The luminous flux and temperature characteristics of InGaN-based white light-emitting diodes (LEDs) intended for automotive headlamps were greatly enhanced by bonding a yellow phosphor to the LED chip using surface activated bonding. The performance of these LEDs was found to be suitable for use as headlamps.

Few studies have evaluated transcatheter aortic valve implantation (TAVI) beyond 5 years. We investigated long-term outcomes (≥5 years) and transcatheter heart valve (THV) performance in patients who had undergone TAVI at least 5 years previously, based on annual follow-up. We reviewed 114 consecutive patients who were of high surgical risk or inoperable and underwent TAVI for severe aortic stenosis from October 2009 to November 2013. There was no lost to follow-up, and median time to death or latest follow-up was 5.0 years (range: 0.1 to 8.5). Structural valve degeneration (SVD) was defined on transthoracic echocardiography (TTE) as follows: (1) mean pressure gradient ≥20 mm Hg with a >10 mm Hg increase from the post-TAVI baseline, and/or (2) moderate or severe transvalvular regurgitation. The mean patient age was 82.7 ± 6.4 years, and 37.7% of patients were men. Median Society of Thoracic Surgeons score was 7.6% (interquartile range 5.8 to 10.9). TTE ≥5 years was 76.1% complete (51 of 67 patients who survived ≥5 years postoperatively). The estimated cumulative survival rates at 1, 3, 5, and 7 years were 88.6%, 72.8%, 58.8%, and 45.3%, respectively. Albumin

The bactericidal effects of air plasma jets produced with a twisted wire-cylindrical electrode configuration were clarified in terms of plasma-induced damage to plant nutrient solutions. The bacterial suspensions were directly irradiated with air plasma jets using a low gas flow rate, which was shown to significantly inactivate the bacteria suspended in the solutions without reducing the nutrient concentrations. However, the plasma irradiation time required for inactivation depended on the type of bacteria; Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) were inactivated in 20–30 s, while Staphylococcus aureus (S. aureus) required 7 min. The inactivation of E. coli and B. subtilis decreased with increasing air gas flow rate, whereas the inactivation of S. aureus was independent of the rate. The inactivation could be attributed to a greater number of reactive oxygen and nitrogen species (RONS) from the air plasma jet, including O2 molecules in the feeding gas attaching to the bacterial suspension surface, which do not harm the nutrient components. This can be derived from the results; the air-plasma-jet-activated nutrient solutions (RONS introduced in the solutions) and the N2 plasma jets had only a limited inactivation effect on the bacteria suspended in the solutions.

Background: The outcome of redo transcatheter aortic valve (TAV) implantation (TAVI) is unknown for TAV structural valve degeneration (SVD). This paper reports the initial results of redo TAVI for TAV-SVD in Japanese patients. Methods and Results: Of 630 consecutive patients, 6 (1.0%) underwent redo TAVI for TAV-SVD (689-1,932 days after the first TAVI). The first TAV were 23-mm balloon-expandable valves (BEV, n=5) and a 26-mm self-expandable valve (SEV, n=1). All patients underwent multidetector computed tomography (MDCT) before redo TAVI, which showed first-TAV under-expansion (range, 19.1-21.0 mm) compared with the label size. Two BEV and 4 SEV were successfully implanted as second TAV, without moderate/severe regurgitation or 30-day mortality. One of 2 patients with a BEV-inside-BEV implantation had a high transvalvular mean pressure gradient post-procedurally (34 mmHg) and required surgical valve replacement 248 days after the redo TAVI. This, however, was unnoted in patients with SEV implantation during redo TAVI. Planned coronary artery bypass grafting was concomitantly performed in 1 patient with a small sino-tubular junction and SEV-inside-SEV implantation because of the risk of coronary malperfusion caused by the first TAV leaflets. Five of the 6 patients survived during the follow-up period (range, 285-1,503 days). Conclusions: Redo TAVI for TAV-SVD appears safe and feasible, while specific strategies based on MDCT and device selection seem important for better outcomes.

Al0.24Ga0.76N thin film surfaces were irradiated simultaneously with CF4 plasma and ultraviolet (UV) at wavelengths of 280 and 310 nm. The UV wavelength and intensity were varied without changing the plasma-generating conditions. These UV photon energies were larger than the band-gap energy of AlGaN film. A compositional change in the simultaneously-irradiated surface depended on the UV wavelength. The 280-nm UV irradiation caused a greater degree of nitrogen deficiency than that introduced by 310-nm UV irradiation, causing the Ga- and Al-rich surface. Moreover, the 280-nm UV irradiation increased the amounts of F atoms and CFx fluorocarbons incorporated into the surface, in comparison with CF4 plasma-only irradiation. In contrast, the 310-nm UV irradiation reduced the amount of the incorporated F atoms and hardly increased the amount of the incorporated CFx fluorocarbons from those caused by CF4 plasma-only irradiation. These became more prominent with increasing UV intensity. These UV wavelength-dependent results can be discussed in terms of four factors: the UV photogenerated-hole-assisted oxidation, the localized surface plasmon resonance, the UV-induced migration of gallium and aluminum vacancies forming stable complexes with F, and the sticking of F-related radicals from CF4 plasma onto the surface.

This study evaluated the characteristics of graphene/AlGaN Schottky barrier photodiodes using graphene as a transparent electrode film and AlGaN as a light-absorbing sensor layer. It was found that the Schottky barrier height of graphene/AlGaN ranged within 1.2–1.7 eV depending on the Al composition ratio. By forming an array of photodiodes, an 8 × 8 pixels ultraviolet image sensor was fabricated.

A Si infrared photodetector that operates without requiring to be cooled was fabricated, and its properties were evaluated. The function of this device is to detect, as an electrical signal, carrier density changes due to stimulated emission utilizing a phonon-assisted process via dressed photons. The photosensitivities of this device were 0.21 A W−1, 0.03 A W−1, and 0.01 A W−1 for wavelengths of 1.3 μm, 1.6 μm, and 2.0 μm, respectively, when the forward current density was 50 A cm−2, and the device exhibited a higher sensitivity for wavelengths greater than the cutoff wavelength.

TiO2 thin films were treated with plasma with the assistance of external heating. This plasma was produced with an O2 dielectric barrier discharge (DBD) at atmospheric and near-atmospheric gas pressures. For comparison, the samples were annealed in O2 gas and also treated with O2 DBD plasma alone. The effects of these treatments on photocatalytic activity were compared by evaluating the photodecomposition of methylene blue dye in aqueous solution. The photocatalytic activity of the heat-assisted plasma-treated sample was the most enhanced among the treatment processes. The net photodecomposition of the heat-assisted plasma-treated sample was slightly higher than or comparable to that of TiO2 anatase-phase nanoparticle powder. The photocatalytic activity enhancement can be attributed to an increase in the effective concentration of photogenerated carriers on the surface. This increase is driven by the synergistic effect between an increase in the depletion layer width and an increase in the optical absorption due to the crystalline transition from the bronze to the anatase phases. This crystalline transition occurred at a lower temperature than the annealing transformation temperature.

An analysis approach utilizing liquid chromatography mass spectrometry (LC-MS) and direct analysis in real time mass spectrometry (DART-MS) is applied to discern the influence of vinylene carbonate (VC) on the cycling performance of a LiNi0.5Mn0.3Co0.2O2 (NMC)/graphite cell at elevated temperature. The VC-containing cell exhibits much improved cycling performance against the elevated temperature rather than the VC-free one. On the basis of the LC-MS results, more decomposition compounds including carbonate oligomers and organophosphates are present in the electrolyte without VC after the initial cycling, while they are less identifiable in the VC-containing electrolyte. On the other hand, the DART-MS results show that a thermally resistant film, which is primarily composed of the cyclic organophosphates, favors forming on the graphite anode surface of the VC-containing cell rather than the VC-free one, preventing further electrolyte decomposition. Moreover, a reaction scheme is proposed to reasonably expl...

Photodecomposition and photobactericidal activities of anatase/rutile-mixed phase TiO2 nanoparticles annealed with low-temperature O2 plasma were clarified by comparing them with those annealed in ambient air. The photocatalytic activities of plasma-assisted-annealed sample greatly enhanced as compared with the untreated sample, under not only ultraviolet irradiation but also visible-light irradiation. The photocatalytic activities of air-annealed samples did not enhance under ultraviolet irradiation but enhanced under visible-light irradiation. The enhanced photocatalytic activities due to the plasma-assisted annealing (PAA) originated from the increased photoexcited carrier concentration. This enhancement was discussed from PAA-induced characteristic factors. PAA facilitated the phase transformation to anatase, contributing directly to extending the photoexcited carrier lifetime. PAA introduced more oxygen vacancies, contributing to trapping more photogenerated electrons. PAA also introduced more bridging/terminal oxygen groups adsorbed on the surface, increasing the upward band-bending, the depletion layer width at the surface, and the charge transfer from rutile to anatase. These two introductions contributed to facilitating the separation of photoexcited carriers. Furthermore, PAA reduced the aggregate size of TiO2 nanoparticles formed on the surface, contributing to increasing optical absorptions. More reactive oxygen species produced from the bridging/terminal oxygen groups by the photoexcited carriers would also enhance the photocatalytic activities.

Al0.24Ga0.76N thin film surfaces were etched with CF4 plasma, with and without the assistance of near-ultraviolet (UV) irradiation. The near-UV source was a black light lamp, which emitted wavelengths of 300–400 nm. The chemical compositions and morphologies of surfaces etched under the two plasma conditions were compared, to clarify the effect of near-UV irradiation on the properties of the AlGaN surface. Near-UV irradiation during CF4 plasma etching reduced the amounts of F atoms, AlFx fluorides, and GaFx fluorides incorporated into the surface, and enhanced the amount of CFx fluorocarbons. Near-UV irradiation did not influence the depth distribution of incorporated fluorine-related impurities, or the degree of nitrogen deficiency caused in the surface. These compositional changes in the surface occurred irrespective of the gas pressure. Near-UV irradiation caused a significant change in the morphology of surfaces etched at high gas pressure (13 Pa), as the etching time was increased to 60 and 100 min. Near-UV irradiation did not change the morphologies of surfaces etched at lower gas pressures (1.3 and 6.7 Pa), irrespective of etching time.

A polychromatic simultaneous wavelength-dispersive X-ray fluorescence (PS-WDXRF) spectrometer can measure the valence changes of 3d transition metals with high precision in the laboratory. Adjustment and maintenance of the drive mechanism are unnecessary, and high-precision measurements are possible in a short time because the optical system has no moving parts and is compact. We have developed a PS-WDXRF spectrometer with improved analytical precision that can measure simultaneously the valence changes of three main elements, Mn, Co, and Ni, which are used as cathode materials in Li-ion batteries (LIBs). In this study, the analytical precision of the spectrometer is evaluated, and its precision is confirmed with actual battery cathodes. The identification precision of the fluorescent X-ray peak energy is

Silicon is one of promising active materials for Li-ion batteries for its high capacity. In order to utilize silicon-based materials as alternative anode, the composite electrodes were prepared from silicon-based materials with various binders (such as acrylic acid, polyimide), conducting materials (AB, CB) and current collecting materials. Pouch cells were composed with the electrode and various separator. To investigate the electrochemical properties of the silicon-based materials anode, an electrochemical test was conducted. From the view point of the safety characterization compared with electrode resistance, the results of nail insertion test for pouch cells were also carried out. In this study cycle performance was heavily dependent on the binder.

AlGaN-based light-emitting diodes (LEDs) are attractive candidates for next-generation light sources in the deep ultraviolet (DUV) region because they can cover the spectral range of 210 – 365 nm through control of the Al content in the epitaxial layers. Moreover, they are environmentally friendly, having zero mercury content and a long lifetime. These excellent properties of AlGaN-based DUV LEDs are suitable for sterilization and polymer curing applications, however, their output power is not yet sufficient for practical applications. One method to improve output power of DUV LEDs is the enhancement of the light extraction efficiency from the LEDs chips to the air by connecting graded refractive index medium outside the chips. The refractive index medium should have the long-term reliability against DUV. We designed and fabricated the hemispherical lensmade of inorganic materials as a refractive index medium, and bonded the hemispherical lenses to the LEDs using room temperature bonding methods. We demonstrated high output power 255 nm and 280 nm LEDs with lenses [M. Ichikawa et al., APEX, to be contributed]. For this study, the excellent properties of fabricated LEDs with lenses are reviewed in connection with the bonded interface structure in light of new experimental data. The following figures (A) and (B) show schematic illustrations of LED chips and hemispherical lenses. We fabricated AlGaN-based 255 nm and 280 nm LEDs on sapphire substrates with a size of 1 mm square. A flip-chip type LED was produced to extract DUV light through the sapphire substrate. A simulation study predicted that the refractive index of the hemispherical lens was optimum when the lens was made of sapphire, which was the same material as that of LED substrates. Moreover, the light extraction efficiency was most enhanced when the lens diameter exceeded 3 mm. Therefore, we fabricated hemispherical lenses made of sapphire, with diameters of 3 or 5 mm. The LED chips were bonded to sapphire lenses at room temperature using two different bonding methods as shown in figure (C). One was surface activated bonding (SAB). In this method, the bonding surfaces of sapphire are sputter-etched and activated using an Ar fast ion beam. Transmission Electron Microscopy (TEM) images revealed that the surfaces of sapphire are consisted of several nanometer-thick amorphous layers, which were the damaged layers of the sapphire by the Ar ion beam irradiation. A large loading force was necessary to bond sapphire to sapphire. However, no light absorption was observed at the SAB interface. Another bonding method was atomic diffusion bonding (ADB). In this method, metal films are fabricated on two flat sapphire surfaces using sputter deposition with subsequent bonding of the two films on the sapphire in vacuum. Very thin Al films were used as the metal films for this study because the extinction coefficient of aluminum is small. A light absorption was slightly observed at the bonded interface in the DUV region. However, sapphire could be bonded without applying too high loading pressures. Moreover, ADB is applicable to bonding any mirror-polished substrates, in addition to sapphire, which is expected to extend the applications. The LEDs with lenses had higher light extraction efficiency than conventionally structured LEDs without lenses. In SAB devices, the maximum external quantum efficiency of the 255 nm LED was 4.56% at 100 mA, and that of the 280 nm LED was 10.1% at 1 A. As a result, at a forward current of 350 mA, the output power of a 255 nm LED with a lens increased by a factor 2.8, reaching 73.6 mW. Furthermore, that of the 280 nm LED increased by a factor of 2.3, reaching 153 mW. The output powers of ADB devices were also significantly higher than those of conventionally structured LEDs without lenses but were slightly lower than those of SAB devices because of a light absorption at the bonding interface. A further enhancement of output powers of ADB devices can be expected by tuning bonding process. The findings in this study would contribute not only to the research in DUV LEDs but also to the research of visible light LEDs. Figure 1

The thermal stability, in terms of cycle and rate performances at 80 °C, and its safety related to lithium ion batteries composed of a LiFePO 4 cathode and SiO anode are investigated. Based on an STEM-EELS analysis, the SiO powder is found to have an amorphous structure, in which nanosized Si particles (Si-rich phase) are uniformly dispersed in the SiO 2 matrix (SiO 2 -rich phase). During the charge/discharge cycling, the cell exhibits a satisfactory cycle performance with a discharge capacity retention of 93.6% and a voltage retention of 93.9% at the 1500 th cycle. Also, the charge and discharge capacity retentions at 10 C are 97.5% and 94.7%, respectively, together with a limited polarization, demonstrating its high rate performance. Furthermore, a 1.16 Ah LiFePO 4 /SiO laminated cell shows negligible voltage and temperature changes during the nail penetration test. The Li concentration in the active material (Si-rich phase) is found to be almost the same as that in the SiO 2 -rich phase after the test. This high thermal stability and safety may be due to the formed layer from the SiO 2 matrix, preventing any side reaction from occurring on the Si surface and isolating the internal current path during the nail penetration.

For further penetration of lithium-ion battery, safer battery design with high energy density is required. In the case of the thermal runaway of conventional lithium-ion batteries, the reaction of electrolyte on the surface of graphite anode at higher temperature causes the gas generation with the temperature rise. Subsequently, the short circuit due to the separator meltdown leads to the oxygen release by the pyrolysis of cathode and the thermite reaction above the melting of aluminum utilized for the current collector and the cell package. The construction of novel safer battery systems with high energy density is possible through a judicious choice of each component: cathode material, electrolyte, separator, anode material, current collector and package. We develop safer battery configurations through the analysis of practical batteries using various techniques such as calorimetry and overcharge / internal short-circuit tests. In this study, we assemble 1 Ah class pouch-type full cell with lithium iron phosphate cathode and silicon oxide anode [1]. The full cell shows good charge-discharge properties even at high-rate and 100˚C (Figure 1). On the estimation, however, the electrochemical energy of both electrode active materials is only about 3% of the total thermal energy of full cell. Thus, we replace aluminum with stainless steel utilized for the current collector and package. In addition, we select a separator of heat-stable nonwoven fabric instead of polyethylene/polypropylene. The total thermal energy of full cell by the alternative separator, current collector and package is found to be reduced to 14% of the initial value. In short-circuit testing, the full cell did not show fire though heat and smoke were generated since the maximum temperature of the cell is only 52˚C. In this way, it is possible to design batteries with highly safe by considering the non-flammability of each component such as the current collector and the package as well as the separator. References [1] M. Yanagida, T. Mukai, Y. Ikeuchi, N. Yamashita, T. Sakamoto, H. Senoh and H. Tanaka, Abstract of the 60th Battery Symposium in Japan, 2B23 (2019). Figure 1

Conclusion These findings suggest that low dose irradiation with 310 nm NB-UVB specifically suppressed the up-regulation of H1R gene expression without inducing apoptosis and that UVB of shorter or longer wavelength than 310 nm NB-UVB had no such effects. Objective To develop a narrowband-ultraviolet B(NB-UVB) phototherapy for allergic rhinitis, this study investigated the effects of irradiation with NB-UVB at wavelength of 310 nm on phorbol-12-myristate-13-acetate (PMA)-induced up-regulation of histamine H1 receptor (H1R) mRNA in HeLa cells. Methods The mRNA levels of H1R in HeLa cells were measured using real-time RT-PCR. Apoptosis were evaluated with DNA fragmentation assay. Results PMA induced a significant increase in H1R mRNA expression in HeLa cells. Irradiation with 305 nm UVB and 310 nm NB-UVB, but not with 315 nm UVB at doses of 200 and 300 mJ/cm(2) significantly suppressed PMA-induced up-regulation of H1R mRNA. At a dose of 200 mJ/cm(2), irradiation with 305 nm UVB, but not with 310 nm NB-UVB, induced apoptosis, although exposure of the cells to both 305 and 310 nm UVB induced apoptosis at a dose of 300 mJ/cm(2) after PMA treatment in HeLa cells. Conversely, irradiation with 315 nm UVB at doses of 200 and 300 mJ/cm(2) did not induce apoptosis.

Compositional and morphological changes in Al 0.24 Ga 0.76 N surfaces etched by CF 4 and Ar plasmas were investigated in order to clarify the effect of fluorine impurities incorporated in the surface by the CF 4 plasma. The CF 4 plasma effectively incorporated the fluorine impurities in the surface even at a short etching time. A small number of the incorporated fluorine impurities only contributed to the formations of Al(OH) x F y and GaF x on the surface even as the etching time increased. Although the CF 4 and Ar plasma etchings preferentially remove nitrogen atoms from the surfaces, the preferential removal induced by the CF 4 plasma etching was suppressed compared with the case of the Ar plasma etching. The CF 4 plasma etching caused a smooth surface regardless of the gas pressure and the etching time, whereas the Ar plasma etching changed the surface morphology depending on the gas pressure and the etching time. The incorporation of the fluorine impurities, which bonded with the cation vacancies such as gallium and aluminum vacancies introduced in the surface by the plasma etching, was considered to concern the suppression of the preferential removal and the formation of the smooth surface.

Enhancement of light transmittance was examined for sapphire or synthetic quartz glass wafers bonded with thin Al films using atomic diffusion bonding (ADB). The results indicate that the thin Al film at the bonded interface diffuses into the wafer by subsequent laser irradiation, which enhances the light transmittance through the bonded interface.

Polypropylene (PP) film surfaces were treated using air-based nonequilibrium atmospheric pressure plasma jets generated with a twisted wires-cylindrical electrode configuration. For comparison, PP samples were also processed with Ar plasma jets. The flux of charged particles imparted to the polymer surface by the air plasma jet greatly increased with decreases in both the gas flow rate and nozzle-to-sample distance, which was not the case for the Ar plasma jet. Reducing the gas flow rate and the nozzle-to-sample distance greatly enhanced the extent to which the surface was rendered hydrophilic by the air plasma within a short treatment time of 1 min. This enhanced effect is believed to originate from a high concentration of oxygen-based functional polar groups (FPGs) containing C O/C OH and C O/C O OH bonds grafted onto the surface. The hydrophilic surfaces resulting from this process also exhibited nanopore structures. The large number of oxygen-based FPGs produced by the air plasma can be attributed primarily to oxygen radical ions impinging from the air plasma on the surface. This can further be attributed secondarily to heat-induced oxidation rather than the sticking of oxygen radicals and UV-induced oxidation from the plasma. The nanoporous structure can also be ascribed to oxidation from UV photogenerated holes.

In the development of lithium-ion batteries (LIBs), cathode materials are being further improved to achieve not only higher energy capacity but also longer cycle life. Analyzing the valence of the cathode active materials during charge and discharge cycles is one of the practical methods to understand the redox mechanism and degradation mechanism, which can help in achieving higher energy capacity and longer life. The valence has been evaluated using X-ray absorption fine structure (XAFS) measurements with a synchrotron X-ray source. To conduct in-house analyses of valence, we developed a polychromatic simultaneous wavelength dispersive X-ray fluorescence (PS-WDXRF) spectrometer, which is comprising an X-ray tube, a slit, a flat analyzing crystal, and a silicon strip detector (SSD) [1]. The X-ray dispersed by the crystal is simultaneously detected by the SSD, and the detected signals at each channel provide intensity information at corresponding energy. Because there are no moving parts in the optical setup, the spectrometer is possible to detect the chemical changes, including valence changes, of 3d transition metals with high precision. Two PS-WDXRF spectrometers were developed. One spectrometer comprises a 1280-channel SSD and a Ge (220) crystal to detect X-rays in the range around 5.38 - 6.52 keV, which is designed for manganese. Another spectrometer comprises same components with another one and the range of detecting X-ray energy is 6.27 – 7.89 keV, which is designed for cobalt and nickel. The first step was to obtain and analyze data of pressed powders of manganese oxides using the spectrometer for manganese. Thus, powders of MnO (II), Mn2O3 (III), MnO2 (IV), and KMnO4 (VII) were placed in the evacuated chamber of the experimental setup. An X-ray tube voltage of 20 kV and a current of 100 mA was applied, and the target was made from Rh and no filter was used. A 5-min measurement was repeated five times for each sample. The PS-WDXRF analysis showed that the specimens achieved clearly different peak energies which belong to more fine electron transition fluorescence lines. This means that the WDXRF has sufficient energy resolution, and the valence information is obtained by the peak energy shift derived from the chemical shift [2, 3]. The second step was to obtain and analyze data of pressed powders of cobalt oxides and nickel oxides using the spectrometer for cobalt and nickel. Thus, powders of CoO(II), LiCoO2(III), NiO(II) and LiNiO2(III) were placed in the evacuated chamber of the experimental setup. An X-ray tube voltage of 20kV and a current of 100 mA was applied, and the target was made from W and no filter was used. This experiment demonstrated the discriminability of fluorescence peak energy shift derived from the chemical shift, in spite of the worse channel resolution. These results indicate that there is a potential for valence evaluation of cathode materials in a short time with highly precise energy resolution. These spectrometers were applied to the evaluation of actual cathode active materials in LIBs which is including manganese, cobalt or nickel. Some different states of cathode materials were prepared and the valence estimation was performed using the PS-WDXRF spectrometers. The relationship between the valence result and state of charge/discharge was confirmed, which shows that the valence number of LIBs cathode material is in accordance with the reaction formula. The recent results of valence evaluation on actual cathode active materials in LIBs will be presented in detail. [1] K. Sato, A. Nishimura, M. Kaino, S. Adachi, X-Ray Spectrom. 46, 330–335 (2017). [2] J. Kawai, M. Takami, C. Satoko, Phys. Rev. Lett. 65, 2193–2196 (1990). [3] K. Sakurai, H. Eba, Nucl. Instr. Meth. Phys. Res. B199, 391–395 (2003).

By comparing differences between characteristics of Al 0.24 Ga 0.76 N thin film surfaces irradiated with ultraviolet (UV) light-assisted CF 4 plasma and with CF 4 plasma, we clarified the effect of UV light irradiation on the surfaces. A black light lamp, which emitted photons with energies of 3.1 to 4.1 eV, was used as the UV light source. The UV light irradiation under a high gas pressure of 13 Pa changed the surface morphology as the irradiation time increased. In the case of low gas pressures of 1.3 and 6.7 Pa, the UV light irradiation did not contribute to the morphological change in the surface. The UV light irradiation also suppressed not only the amount of F atoms incorporated but also the amount of fluorides, Al(OH x )F y and GaF x , formed in the surface. In contrast, the amount of CF x incorporated in the surface was enhanced. These compositional change in the surface occurred irrespective of gas pressure.

The three-dimensional imaging of threading dislocations in GaN films was demonstrated using two-photon excitation photoluminescence. The threading dislocations were shown as dark lines. The spatial resolutions near the surface were about 0.32 and 3.2 µm for the in-plane and depth directions, respectively. The threading dislocations with a density less than 108 cm−2 were resolved, although the aberration induced by the refractive index mismatch was observed. The decrease in threading dislocation density was clearly observed by increasing the GaN film thickness. This can be considered a novel method for characterizing threading dislocations in GaN films without any destructive preparations.