Search

The purpose of this study was to determine the ocular, sex- and age-specific, anthropometric, and hematologic factors that affect the implicit times and amplitudes of the flicker ERGs recorded with the RETeval system from individuals 40- to 89-years-of-age. Flicker ERGs were recorded with the RETeval system from 330 individuals who had normal fundus and OCT images. Univariate and multivariate regression analyses were performed to identify factors associated with the implicit times and amplitudes of the RETeval flicker ERGs. Univariate regression analyses showed significant correlations between the implicit times and the BCVA, age, axial length, blood sugar level, and BUN in both eyes. Multivariate regression analyses identified age and axial length as two independent factors that were significantly correlated with the implicit times of the RETeval flicker ERGs. Univariate regression analyses also showed significant correlations between the amplitudes and age, platelet count, HDL level, and creatinine level in both eyes. However, smoking habits, body mass index, and blood pressure were not correlated with the RETeval flicker ERGs. We conclude that age and some ophthalmologic and hematologic findings except for anthropometric findings were suggested to significantly affect the measurements of the RETeval flicker ERGs.

The increase of electric mobility is leading to new drivetrain designs in vehicle development. A common problem in electric drivetrains are torsional oscillations caused by elastic components. These components are wheel shafts, tires and bushings. A common problem, its sensitivity to parameter variation has not yet been fully investigated. The objective of this study is to quantify the sensitivity of oscillation frequency, damping and coupling between components with respect to key drivetrain parameters. A parameter space is investigated using Monte-Carlo sampling. A linear state space model is parameterized for each sample. Modal analysis permits the analysis of oscillation frequency, damping and coupling between components using the state variables. Subsequently, a Gaussian mixture model clusters the resulting data to form mode groups. Finally, linear regressions quantify the sensitivities. The results show oscillation damping can be increased by stiff wheel shafts. Decoupling of components in oscillation modes is mainly achieved by separating the oscillation frequencies of the different modes.

We investigated the prevalences and risk factors for peri-implant diseases in Japanese adult dental patients attending a follow-up visit at dental hospitals or clinics as part of their maintenance program. This cross-sectional multicenter study enrolled patients with dental implants who attended regular check-ups as part of a periodontal maintenance program during the period from October 2012 through September 2013. Patients with implants with at least 3 years of loading time were included in the study. The condition of peri-implant tissue was examined and classified into the following categories: healthy, peri-implant mucositis, and peri-implantitis. Patients were also evaluated for implant risk factors. A total of 267 patients (110 men, 157 women; mean age: 62.5 ± 10.7 years) were analyzed. The prevalence of patient-based peri-implant mucositis was 33.3% (n = 89), and the prevalence of peri-implantitis was 9.7% (n = 26). Poor oral hygiene and a history of periodontitis were strong risk factors for peri-implant disease. The present prevalences were lower than those previously reported. The quality of periodontal therapy before and after implant installation and patient compliance and motivation, as indicated by plaque control level, appear to be important in maintaining peri-implant tissue health.

For future low carbon mobility society, new-type small electric vehicles (EVs) are developed actively in recent period. To reduce the energy consumption in various actual driving conditions, considering overall running resistance from tire characteristics, mechanical losses and electrical losses is necessary. In this paper, modelbased development of system performance of a new EV is described. Full vehicle model considering both vehicle dynamics and energy consumption was developed using Modelica. Research for both structure and specification of components of the vehicle and also of the control were performed to find the solution to satisfy both energy consumption and vehicle dynamics by using the full vehicle model. Finally trade-off between vehicle stability and energy consumption and also between driver workload and energy consumption by using direct yaw moment control was indicated.

For future low carbon mobility society, new-type small electric vehicles (EVs) are developed actively in recent period. To reduce the energy consumption in various actual driving conditions, considering overall running resistance from tire characteristics, mechanical losses and electrical losses is necessary. Also, to cope with reduced stability against external disturbances because of the light weight, it is necessary to apply vehicle dynamics control utilizing direct yaw moment control. In this paper, model-based performance development of a new electric vehicle is described. Full vehicle model considering both vehicle dynamics and energy consumption was developed using Modelica. Research for both structure and specification of components of the vehicle and also of the control were performed to find the solution to satisfy both energy consumption and vehicle dynamics by using the full vehicle model.

当工場の4号ボイラー（循環流動層式）は1995年に3号ボイラー（重油焚き）から燃料転換のため稼動した。4号ボイラーの最大蒸発量は120t／hで4台のマシンが稼動していた時は，95t／h～120t／hで運転していた。2002年より大型マシン1台の稼動日数が減少し，2003年1月より休止したため負荷は75t／h～96t／hとなった。低負荷運転では，火炉底部の燃焼空気吹き込み口のノズルが閉塞してくる。このため，最低負荷を75t／hにして運転していた。大型マシン休止後，その他のマシン休転整備時には工場使用電力が減少し，ボイラー負荷が75t／hでは，発電電力が多すぎて電力会社へ逆送となるため，タービンバイパスで大気放出する運転状態が発生してきた。大気放出を減少させるためには，ボイラーの負荷をさらに下げる必要があり，そのため燃焼用空気吹き込み口であるグリッドノズルの改造が必要となった。グリッドノズルの形状をピッグテイルノズルからアローヘッドノズルに変更することによりノズル穴にベッド材の侵入を防ぐようにし，低負荷運転でもノズルが閉塞しないように対策した。現在の最低負荷は62t／hまで下がっており，計算による閉塞率は23％と問題ない状況であり大気放出はせずに運転できている。ボイラーの低負荷対策による大気放出削減量は約600t／月となっている。

To cope with demands for future low carbon society, development of new-type small electric vehicles (EVs) becomes very active. To reduce the energy consumption in various actual driving conditions, considering overall running resistance such as aerodynamic resistance, tire rolling resistance including cornering drag, mechanical and electrical losses, etc. will be necessary. On the other hand, to cope with reduced stability against external disturbances such as side wind because of the light weight, it was clarified that additional control of direct yaw moment is effective. In this paper, model-based development of a new electric vehicle using Modelica is described. Full vehicle model considering both vehicle dynamics and energy consumption was developed and utilized to investigate the best possible solutions for both basic design of the vehicle and design of the control system.

We have investigated a quasi-phase-matching AlGaAs waveguide using cathodoluminescence spectroscopy and atomic force microscopy. We found that the anisotropic diffusion of Al/Ga atoms causes Al-composition modulation as well as interface corrugations.

We have investigated a periodically-inverted Al0:40Ga0:60As layer in a quasi-phase-matching AlGaAs waveguide using cathodoluminescence spectroscopy, and found that Al-composition modulation is formed by the anisotropic diffusion of Al/Ga atoms during the molecular-beam epitaxy growth process.

We have shown that photoelastic effect alters the phase-matching wavelengths of Type-I and Type-II quasi-phase-matched second-harmonic generation in a periodically-inverted AlGaAs waveguide through the uniaxial strain in the pseudomorphic AlGaAs layers.

We have fabricated high-quality periodically-inverted AlGaAs ridge waveguides by introducing the low temperature MBE growth process, and achieved relatively low propagation losses and highly efficient quasi-phased matched second-harmonic generation pumped at 1.55 um.

Wavelength conversion via quadratic optical nonlinearity in AlGaAs-based waveguiding devices will be presented. Efficient quasi-phase-matched nonlinear conversions are demonstrated in periodically inverted AlGaAs waveguides. A novel device utilizing birefringence in thin high-index-contrast waveguide is proposed.

To realize highly efficient intermediate-band solar cells (IB-SCs), a long lifetime of photo-generated carriers in the IB is essential. We propose a new concept for this purpose based on IB absorbers using quantum-dots (QDs). By inserting potential walls between QDs and barriers that form a type II band alignment, electrons in the IB and holes in the valence band are farther separated compared to those in a conventional type II QD material, leading to significant reduction of radiative recombination. We designed a concrete structure using InAs QDs, GaAs1−xSbx barriers, and GaAs walls to find the suitable GaAs wall thickness and Sb content being 2 nm and x = 0.18, respectively, and demonstrated a lifetime of electrons excited to the IB as long as 220 ns.

To realize highly efficient intermediate-band (IB) solar cells, long lifetime of photo-generated carriers in the IB is essential. For this purpose, we propose a concept for IB absorbers using GaAs wall-inserted type II InAs quantum-dots (QDs), in which electrons at the IB of the InAs QDs and holes in the valence band of the GaAsSb layers are farther separated compared to those in conventional type II QDs. We fabricated InAs/GaAs/GaAs0.82Sb0.18 type II QDs and performed time-resolved photoluminescence spectroscopy. The obtained lifetime was as long as 220 ns for electrons at the IB.

We report very long intrinsic radiative recombination lifetime τrad in type II InAs quantum dots embedded in GaAs1−xSbx. The dependence of photoluminescence (PL) decay time τPL on both the Sb composition (x = 0–0.18) and excitation intensity (38–460 mW/cm2) was systematically investigated by time-resolved PL measurements with a time-correlated single-photon counting method. All PL decay curves exhibited non-exponential profiles, and τPL was strongly dependent on the excitation intensity. These properties were well explained by solving rate equations of carrier density with neglecting nonradiative process, in which τrad is inversely proportional to carrier density. The 18% Sb sample exhibited a τPL of over 100 ns under weak excitation, which is longer than twice the previously reported values. We evaluated the value of τrad in InAs/GaAs1−xSbx QDs relative to that in type I InAs/GaAs QDs based on an effective mass approximation and found that the observed extremely long τPL corresponds to τrad.

We have improved fabrication processes of periodically inverted AlGaAs waveguides for highly efficient quasi-phase-matched wavelength conversion. In order to reduce propagation losses in waveguiding devices fabricated based on sublattice reversal epitaxy, we have introduced template planarization by chemical mechanical polishing and low-temperature regrowth technique. Corrugations at the core/clad interface and the propagation loss at 1.55 µm has been reduced to 40 nm and 9 dB/cm, respectively. First-order quasi-phase-matched second-harmonic generation was demonstrated at 1.55 µm fundamental wavelength with a 1.47-mm-long device. Obtained internal conversion efficiency is 2.2%/W which is one order of magnitude lower than the theoretical value for an ideal lossless waveguide. A significant increase in the conversion efficiency is expected with a redesign of the device and further optimization of the fabrication processes.