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Ni/p-type SiC Schottky barrier diodes with various acceptor densities (N A = 5 × 1015 to 3 × 1019 cm−3) are fabricated and the measured current–voltage characteristics are analyzed by numerical calculation of tunneling current. The tunneling current is calculated taking account of multiple valence bands. It is revealed that tunneling of holes in the split-off band, which has a light effective mass (0.21m 0), is the dominant conduction mechanism at metal/heavily-doped p-type SiC Schottky interfaces.

Mg contacts are formed on P+-implanted SiC (1 × 1017–8 × 1019 cm−3) and their current–voltage characteristics and contact resistivity (ρ c) are analyzed. The current density through the contacts on the ion-implanted SiC is several orders of magnitude larger than that on SiC epitaxial layers with the same doping density. For the Mg contacts formed on ion-implanted SiC with 8 × 1019 cm−3, a very low ρ c of 2 × 10−6 Ωcm2, which is comparable to that of typical Ni-based contacts sintered at high temperature, is achieved without any thermal treatment after electrode deposition.

In this study, n-type SiC Schottky barrier diodes (SBDs) with various doping concentrations ([Formula: see text]–[Formula: see text]) were fabricated, and their forward and reverse current–voltage ( I– V) characteristics were analyzed focusing on tunneling current. Numerical calculation with the fundamental formula of tunneling current gives good agreement with experimental forward and reverse I– V curves in the heavily doped SiC SBDs ([Formula: see text]). The analysis of the energy where electron tunneling most frequently occurs revealed that field emission (FE) tunneling dominates conduction instead of thermionic field emission (TFE) under a higher electric field in reverse-biased heavily doped SiC SBDs, while forward I– V characteristics are described only by TFE. In addition, the critical electric field for the TFE–FE transition is quantitatively clarified by carefully considering the sharply changing electric field distribution in SiC with a high donor concentration.

We have demonstrated a direct metallic conversion from nickel hydroxide nanosheets to nickel metal nanostructures by thermal annealing in vacuum. The metal transition of the single-layer nanosheets deposited on a Si substrate was revealed by x-ray absorption near edge structure (XANES) measurements. The XANES signal significantly changed at annealing temperatures above 250 °C. The metal transition temperature coincides with the reported temperatures at which layered nickel hydroxide nanosheets are converted to nickel oxide nanosheets by calcination in air. Auger measurements confirmed that a dissociation of oxygen from the hydroxide nanosheet induces the metallic conversion. The converted nickel metallic structures exhibit ferromagnetic behavior revealed by x-ray magnetic circular dichroism (XMCD) measurement. Atomic force microscopy measurements indicate that diffusions of nickel atoms on the substrates leads to a structural change from a 2D-like structure to a particle-like structure.

We investigated the Hall electron mobility in 4H-SiC along and perpendicular to the c-axis (μ H,// and μ H,⊥) using Hall bar structures fabricated on n-type SiC( 11 2 ̅ 0 ) epitaxial layers over a wide range of donor concentration (2.1 × 1015–3.2 × 1018 cm−3) and temperature (298–600 K). We obtained μ H,// of 1160 cm2 V−1s−1, which is the highest electron mobility ever reported for SiC measured at room temperature. The anisotropy of drift mobility becomes smaller at higher temperature and with higher donor concentration. This result can be qualitatively explained by smaller anisotropy of electron effective mass in the high-energy region of the conduction band.

We constructed the SCRIT (Self-Confining Radioactive Ion Target) electron scattering facility to realize electron scattering off short-lived unstable nuclei at RIKEN in Japan. Electron scattering is one of the most powerful and reliable tools to study structures of atomic nuclei. However, it has been extremely difficult to apply electron scattering to unstable nuclei because of target preparation problems. SCRIT is a novel ion-trapping technique that achieves high luminosity of more than 1027 cm-?2s-?1 with a small amount of target ions. Following completion of the facility, a series of commissioning experiments of the entire facility with several stable nuclear targets, including 208Pb and 132Xe, were performed. Momentum transfer distributions of elastic scattering from those targets were successfully measured at several electron beam energies, and the charge density distribution of the 132Xe nucleus was extracted for the first time.

Background For over 20 years, Madagascar has been challenged by continued high prevalence of stunting, underweight and wasting among children under 5 years of age. Yet, nutritional status of post-under-five age group has never been assessed in the country, despite its importance in relation not only to physical health but also to cognitive capacity and educational achievements of children. This study aims to estimate prevalence of malnutrition among schoolchildren aged 5–14 years in Madagascar. It further attempts to identify the possible risk factors for their malnutrition. This is the first study that estimates prevalence of malnutrition among school-aged children in Madagascar. Methods A cross-sectional household survey was conducted in Antananarivo-Avaradrano district, Analamanga region, Madagascar. The study targeted 393 first and second graders 5–14 years of age enrolled at 10 primary schools, where school-feeding was implemented. Data were collected from anthropometric measurements, their subsequent household structured interviews and observations. Bivariate (Chi-square test or Mann-Whitney’s U test) and multivariable (logistic regression) analyses were performed, to identify the possible risk factors associated with malnutrition. Results The overall prevalence rates of stunting, underweight and thinness were 34.9%, 36.9% and 11.2%, respectively. Nineteen children (4.8%) suffered from all the three forms of undernutrition. Older schoolchildren had a significantly greater likelihood of being stunted, underweight and thin. The greater number of members a household had, the higher likelihood of being stunted and thin its schoolchild had. Children having lower Household Dietary Diversity Score were more likely to be underweight. Yet, ‘Had lunch at school yesterday’ was associated neither with being stunted nor with being underweight and thin. This implies room for improvement of the current school feeding program. Conclusions Prevalence rates of stunting and underweight among 393 children examined were as high as the national averages among children under 5 years of age. Adequate food availability and dietary diversity over a sufficient period (incl. 5–14 years of age) are necessary for increasing likelihood of catch-up in height-for-age and weight-for-age, which are expectable during adolescence. To supplement inadequate household dietary diversity practices, school-feeding program may need to use more animal-protein ingredients. Electronic supplementary material The online version of this article (10.1186/s12889-019-7013-9) contains supplementary material, which is available to authorized users.

The barrier heights in Ti/ and Ni/n-SiC Schottky barrier diodes (SBDs) in a wide range of the donor density (N d = 2 × 1017–1 × 1019 cm−3) were investigated. The forward current–voltage characteristics in the heavily-doped SBDs (N d > 2 × 1017 cm−3) are described by the thermionic field emission (TFE) model, which includes an electron tunneling induced by the high electric field (> MV cm−1) at the Schottky interface. The high electric field also causes significant image force lowering (Δϕ ∼ 0.2 eV) in the heavily-doped SBDs (N d = 1 × 1019 cm−3). Through the analysis carefully considering such strong image force lowering, the same slope of the barrier height versus the metal work function plot (S ∼ 0.7) is obtained regardless of N d. This indicates that metal/SiC interfaces are nearly free from Fermi-level pinning independent of N d.

We have investigated molecule adsorption phenomena on a chemically active surface of titanium oxide nanosheet by coupling with an electrically sensitive graphene field effect transistor (FET). Super-hydrophilic surface of the titanium oxide nanosheet forms a water-layer in ambient air which exhibits a large hysteresis of drain current in the hybrid FET for sweeping gate-voltage. The large hysteresis disappears in vacuum, which indicates physically adsorbed water molecules on the surface of the titanium oxide nanosheet dominantly contribute to the hysteresis. UV light irradiation in vacuum significantly changes the drain current due to desorption of the adsorbed molecules. Sufficient UV irradiation results in symmetric gate-voltage dependence similar to those of conventional graphene FETs. Exposure to an oxygen gas atmosphere leads to a heavy hole doping in the FET, where the binding of the oxygen molecules is stronger than that of water molecules. In a humidified nitrogen atmosphere, a large shift of charge neutrality point is observed in transfer characteristics crossing between electron doping and hole doping. By contrast, a clear square-shaped hysteresis loop is observed in a humidified oxygen atmosphere, where the hole density in the graphene drastically changed with O2/H2O redox couple reaction on the titanium oxide nanosheet.

We have developed a new synthesis method that includes a chemical vapor deposition process in a chamber settled in organic liquid, and applied its nonequilibrium reaction field to the development of novel carbon nanomaterials. In the synthesis at 1110–1120 K, using graphene oxide as a catalyst support, iron acetate and cobalt acetate as catalyst precursors, and 2-propanol as a carbon source as well as the organic liquid, we succeeded to create carbon nanofiber composed of novel pot-shaped units, named carbon nanopot. A carbon nanopot has a complex and regular nanostructure consisting of several parts made of different layer numbers of graphene and a deep hollow space. Dense graphene edges, hydroxylated presumably, are localized around its closed end. The typical size of a carbon nanopot was 20–40 nm in outer diameter, 5–30 nm in inner diameter, and 100–200 nm in length. A growth model of carbon nanopot and its applications are proposed.

Herein, titania thin films are fabricated by a facile liquid-phase method based on vacuum filtration of a colloidal suspension of titania nanosheets, which is followed by thermal annealing to transform the nanosheet film into anatase TiO2. Nanosheet-derived titania thin films exhibit poor resistive switching with an interface-type mechanism. This behaviour is distinct from the filamentary switching that has been observed with titania thin films fabricated by other conventional techniques. This tolerance against conducting-filament formation may be ascribed to a low concentration of oxygen vacancies in nanosheet-derived films, which is expected because of the O/Ti ratio of titania (Ti0.87O2) nanosheets being larger than that of TiO2. Besides, the dielectric breakdown strength of nanosheet-derived films is found to be comparable to or higher than that of titania thin films fabricated by other techniques. These findings clearly indicate the usefulness of nanosheet-derived titania thin films for dielectric applications.

We investigated the doping concentration dependence of the barrier height and forward carrier transport mechanism in Ni/SiC Schottky barrier diodes (SBDs) in the wide range of 6.8 × 1015–. Forward current–voltage characteristics in heavily-doped SiC SBDs () can be well reproduced by a thermionic field emission model. The barrier height decreased with increasing doping concentration and the barrier height drop in the most heavily-doped SBD () was about 0.2 eV, which quantitatively agreed with the image force lowering of 0.18 eV caused by the high electric field.

Background: Many studies have reported the association between body mass index (BMI) and fasting lipid profiles in children. However, little information exists about the screening of dyslipidemia in the non-fasted state. This study assessed whether BMI can predict non-fasting lipid abnormalities in children. Methods: Using gender-separated analysis, 3895 boys and 3866 girls (aged 11–12 years) were investigated. Total cholesterol (TC), triglyceride (TG) and HDL-cholesterol (HDL-C) were measured, and non-HDL-C (=TC−[HDL-C]) was calculated. A BMI z-score was employed as the weight status. Gender-specific 95th percentiles of TC, TG and non-HDL-C were defined as “elevated”, with the 5th percentiles of HDL-C defined as “reduced”. Results: TG and non-HDL-C were positively, and HDL-C was negatively correlated with the BMI z-score in both genders. Both obese (2z-score) and overweight (1z-score≤2) were associated with the risks of elevated TG, non-HDL-C and reduced HDL-C. In both genders, a receiver operating characteristic curve demonstrated that the utility of predicting the above lipid abnormalities was moderate; the areas under the curve ranged from 0.60 to 0.70. The optimal cut-off for the BMI z-score for predicting elevated TG, non-HDL-C and reduced HDL-C were 0.52, 0.55 and 0.51 in boys and 0.34, 0.38 and 0.35 in girls, respectively. Conclusions: The BMI could be an indicator of abnormalities of non-fasting TG, non-HDL-C and HDL-C in both genders.

Oxygen functional groups (OFGs) in graphene oxide (GO) are responsible for the unique optical, electrical, magnetic as well as ionic, liquid and gaseous transport properties. In the present study, we have discovered reversible epoxide opening/closing reactions in GO upon alkaline and acid treatments, respectively, under ambient conditions. We suggest that unique properties of GO including stability of the carbocation and fast proton migration on the surfaces enable the unusual pH-driven epoxide ring opening/closing reactions. Our experimental results indicate that an irreversible epoxy formation observed in base-treated GO under flux conditions is due to the decomposition of the vic-diol groups formed by epoxy ring opening in alkaline solutions. A high concentration of basal plane epoxides is a remarkable feature of GO. Thus, the reversible epoxy formation should be an important part of our understanding of reactivity and properties of GO. For example, the epoxy ring opening can be a mechanism for anomalous photoluminescent (PL) quenching of GO dispersions in alkaline conditions.

We have constructed the SCRIT electron scattering facility at RIKEN in order to realize electron scattering off unstable nuclei. Because electron scattering is the most powerful and reliable tool to study the internal structure of the atomic nuclei as demonstrated for many stable nuclei in the latter half of the 20th century, actualization of electron scattering for the unstable nuclei has been long awaited. Recently, we have performed a series of elastic electron scattering experiments with $^{132}$Xe target. The high luminosity of around 10$^{27}$~cm$^{-2}$s$^{-1}$ which is a minimum-requirement for electron scattering is achieved with using only 10$^8$ target ions. By comparing with a DWBA calculation assuming the two-parameter Fermi distribution as the nuclear charge density distribution, it is found that a root-mean-square of radius is consistent with that from the measurement of X-ray of muonic atom and an information of surface shape of $^{132}$Xe nucleus is extracted for the first time.

The SCRIT (Self-Confining Radioactive-Isotope Ion Target) electron scattering facility has been constructed at the RIKEN RI Beam Factory. In the commissioning experiment, the ion-trapping properties of the SCRIT system were studied using stable ions. By using an electron spectrometer, the momentum transfer distribution of the electron elastic scattering of $^{132}$Xe was measured at 150, 200, and 300~MeV, and the charge density distribution was deduced. During the measurements, a luminosity of $1.8 \times$10$^{27}$~cm$^{-2}$s$^{-1}$ was achieved with a 250-mA electron beam and only 10$^8$ trapped ions. Production of RIs has begun in an electron-beam-driven RI separator, and developments are underway to increase the production rate of short-lived nuclei. Soon, measurements of electron elastic scattering by short-lived nuclei will be performed.

The SCRIT (Self-Confining RI Ion Target) facility has been constructed at RIKEN to make the electron-RI scattering experiment possible for the first time in the world. At SCRIT, the angular momentum distribution of scattered electrons is measured by WiSES (Window-frame Spectrometer for Electron Scattering) which consists of a dipole magnet and front/rear drift chambers, covering a solid angle of $\sim$80 mSr with an intrinsic momentum resolution of $\Delta p/p\sim10^{-3}$. Also the luminosity of the electron-RI scattering is estimated from bremsstrahlung photons measured by LMon (Luminosity Monitor) to obtain the absolute cross-section of the scattering. The LMon consists of a CsI calorimeter to measure the photon energy, and plastic fiber scintillators to measure the 2D hit distribution of the bremsstrahlung photons. In 2015-2016 the first physics experiment has been performed using $^{132}\rm Xe$ target, then the luminosity and angular distributions were successfully measured at the electron beam energy of 150-300 MeV, achieving a luminosity above $10^{27}cm^{-2}$s$^{-1}$. In this article, we present the performances of the WiSES and LMon detectors obtained by using the $^{132}\rm Xe$ experiment data.

To establish a biotechnological system to convert CO2 into methane, we are trying to develop a new CO2 bio-conversion technology based on “electromethanogenesis”, a new bio-electrolysis reaction using microbially-catalyzed electrode. In this study, we characterized bio-electrochemical properties of electromethanogenic reaction by Methanothermobacter thermautotrophicus strain AH, a thermophilic methanogen. The methanogen can electromethanogenically produce methane without exogenously-supplied hydrogen. In the reaction, the methanogen utilized molecular hydrogen, which was evolved by the abiotic electrochemical reaction, for the hydrogenotrophic methanogenesis. The current-to-methane conversion efficiency was 20% and the hydrogen evolution reaction was the rate-limiting step of the reaction.

The Beijing 2008 Olympics Research and Development Project (B08RDP), initiated in 2004 under the World Meteorological Organization (WMO) World Weather Research Programme (WWRP), undertook the research and development of mesoscale ensemble prediction systems (MEPSs) and their application to weather forecast support during the Beijing Olympic Games. Six MEPSs from six countries, representing the state-of-the-art regional EPSs with near-real-time capabilities and emphasizing on the 6–36-h forecast lead times, participated in the project. The background, objectives, and implementation of B08RDP, as well as the six MEPSs, are reviewed. The accomplishments are summarized, which include 1) providing value-added service to the Olympic Games, 2) advancing MEPS-related research, 3) accelerating the transition from research to operations, and 4) training forecasters in utilizing forecast uncertainty products. The B08RDP has fulfilled its research (MEPS development) and demonstration (value-added service) purposes. The research conducted covers the areas of verification, examining the value of MEPS relative to other numerical weather prediction (NWP) systems, combining multimodel or multicenter ensembles, bias correction, ensemble perturbations [initial condition (IC), lateral boundary condition (LBC), land surface IC, and model physics], downscaling, forecast applications, data assimilation, and storm-scale ensemble modeling. Seven scientific issues important to MEPS have been identified. It is recognized that the daily use of forecast uncertainty information by forecasters remains a challenge. Development of forecaster-friendly products and training activities should be a long-term effort and needs to be continuously enhanced. The B08RDP dataset is also a valuable asset to the research community. The experience gained in international collaboration, organization, and implementation of a multination regional EPS for a common goal and to address common scientific issues can be shared by the ongoing projects The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble—Limited Area Models (TIGGE-LAM) and North American Ensemble Forecast System—Limited Area Models (NAEFS-LAM).

The study aimed to clarify the antitumor effects of radiotherapy, chemotherapy, hyperthermia, and combinations thereof in an effort to devise a highly effective noninvasive regimen. The human KB cell line, derived from an epidermal carcinoma of the mouth, was used for the experiments. The antitumor effects of monotherapy—with radiotherapy of 6-MV X-rays, 43°C hyperthermia, and chemotherapy with the taxoid antineoplastic drug docetaxel—as well as combinations of these therapies were evaluated using a colony assay. Compared with monotherapy of 6-MV X-rays, 43°C heat, and docetaxel, radiation combined with 43°C heat showed a slight increase in sensitization; radiation or 43°C heat combined with docetaxel showed stronger sensitization. Furthermore, more pronounced sensitization was observed with a three-way combination of radiation, 43°C heat, and docetaxel. These results suggest that the combined use of radiation, 43°C heat, and docetaxel will improve the therapeutic efficacy against malignant tumors by increasing sensitization to the antitumor effects of each therapy. The results also suggest that it is possible to reduce the dosage of the individual therapies in combination therapy.

The Japan Meteorological Agency keeps records of geomagnetic phenomena observed at Kakioka (magnetic latitude, 27.47°), Memambetsu (magnetic latitude, 35.44°), and Kanoya (magnetic latitude, 22.00°). We used these records to examine the cumulative frequency distribution of magnetic storms, sudden impulses, and storm sudden commencements. The distributions of magnetic storms resemble the Gutenberg–Richter relation between earthquake frequency and magnitude used in seismology. The coefficients determined with the maximum likelihood method show that when the H-range of a magnetic storm at Kakioka is doubled, the frequency of the magnetic storm is about one seventh, for example. Intense magnetic storms occur less frequently than calculated by the functions. This statistical analysis proves that there are no significant differences between slopes of the frequency distribution functions of the magnetic phenomena at Kakioka, Memambetsu, and Kanoya.

We describe a case of huge solitary neurofibroma in the oral cavity. A 59-year-old man with a history of dysphagia presented with swelling of the tongue. Magnetic resonance (MR) images showed a lesion extending from the base of the tongue to the floor of the mouth located above the mylohyoid muscle. The dimensions of the enucleated tumor were 95 mm in length, 65 mm in width, and 15 mm in thickness. Histopathological examination revealed that the lesion was a diffuse neurofibroma.

Sialolipoma is a new variant of salivary gland lipoma, which was first described in 2001. We report a rare case of sialolipoma of the palate, and review another 10 cases affecting the minor salivary gland and 13 affecting the major salivary gland, together with details of the clinical and histopathological findings.

SUMMARYThe ciliated protozoan Paramecium spontaneously changes its swimming direction in the absence of external stimuli. Such behavior is based on resting potential fluctuations, the amplitudes of which reach a few mV. When the resting potential fluctuation is positive and large, a spike-like depolarization is frequently elicited that reverses the beating of the cilia associated with directional changes during swimming. We aimed to study how the resting potential fluctuation is amplified. Simultaneous measurements of the resting potential and intracellular Ca2+([Ca2+]i) from a deciliated cell showed that positive potential fluctuations were frequently accompanied by a small increase in[Ca2+]i. This result suggests that Ca2+influx through the somatic membrane occurs during the resting state. The mean amplitude of the resting potential fluctuation was largely decreased by either an intracellular injection of a calcium chelater (BAPTA) or by an extracellular addition of Ba2+. Hence, a small increase in[Ca2+]i amplifies the resting potential fluctuation. Simulation analysis of the potential fluctuation was made by assuming that Ca2+ and K+ channels of surface membrane are fluctuating between open and closed states. The simulated fluctuation increased to exhibit almost the same amplitude as the measured fluctuation using the assumption that a small Ca2+ influx activates Ca2+ channels in a positive feedback manner.

Papillary squamous cell carcinoma (PSCC) is a rare variant of squamous cell carcinoma (SCC) having an exophytic papillary component. We report the case of a 60-year-old woman with oral PSCC of the gingiva. Histopathologically, the operative specimen was composed of exophytic papillary and invasive proliferations of atypical squamous epithelium, from which a pathological diagnosis of PSCC was made. On the Ki-67 labeling index, the exophytic area of PSCC (42.8%) was higher than the superficial area of SCC (20.7%) and papilloma (38.9%). The invasive area of PSCC (53.1%) was slightly higher than that of SCC (52.2%). The PSCC had high proliferative activity in both the exophytic and invasive areas, which reflected the PSCC characteristic features of papillary and invasive growths. Clinicians should check for the existence of PSCC in the oromaxillofacial region and provide treatment as they do for SCC.

This article adopts an input perspective in examining a poverty-of-the stimulus (POS) learning situation in second language acquisition (SLA). Analysis of grammaticality judgement data from 81 English-speaking and 85 Chinese-speaking learners of Japanese isolates triggering input that informed English learners of subtle semantic properties of the ni direct passive underdetermined by second language (L2) input. The study shows a sufficient correlation in the case of English learners between acquisition of the ni direct passive's triggering properties (available through input) and acquisition of its POS properties (unavailable through input). Importantly, those properties are direct consequences of affectivity, an underlying semantic property of the ni direct passive. That correlation does not obtain in the case of Chinese learners due to a positive first language (L1) effect. Additional corroborating evidence comes from acquisition of another Japanese passive, the ni yotte, for which no correlation was found between its non-triggering and non-POS properties for either English or Chinese learners as those properties are available through input. The article proposes that English learners' computation of a target-like conceptual representation of the triggering input leads to the restructuring of their lexical—conceptual representation of the ni direct passive.

Toshimi Suda1 , Akitomo Enozokizono2, Masahiro Hara3, Yuji Haraguchi4, Sin’ichi Ichikawa3, Kazuyoshi Kurita2, Saki Matsuo2, Tetsuya Ohnishi3, Tadaaki Tamae1, Mamoru Togasaki2, Kyo Tsukada1,Teruaki Tsuru1, Shuo Wang5, Shunpei Yoneyama1 and Masanori Wakasugi3 1Research Center for Electron-Photon Science, Tohoku University, 1-2-1 Mikamine, Sendai, 981-0928, Japan 2Department of Physics, Rikkyo University, Ikebukuro, Tokyo, 171-8501, Japan 3Nishina Center, RIKEN, Wako, Saitama,351-0198, Japan 4Department of Electrical Engineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2137, Japan 5School of Space Science and Physics, Shandong University, Weihai, China

This study is focused to the effects of plastic working on the fatigue strength of Ti-6Al-4V alloy with notch. In general, the fatigue strength of plastic worked specimen is higher than that of non-worked one. However, the potential of hardening ability of Ti-6Al-4V alloy is very limited. Accordingly, the effect of work hardening on fatigue strength about this material is very small. In addition, the surface of the worked part becomes rougher with increasing plastic deformed value and the fatigue cracks initiate at this part. Consequently, the fatigue limit of the plastic worked specimen is lower than that of the non-plastic-worked one.