Search

Study question Is it possible to determine the difference between 2.1 pronuclear (2.1PN) zygotes and tripronuclear (3PN) zygotes from time-lapse images? Summary answer A pronucleus of less than 15 μm in diameter can be considered the micro pronucleus (micro PN), and it is possible to classify 2.1PN zygotes. What is known already 2.1PN zygotes are defined as zygotes with two pronuclei and one smaller pronucleus. Capalbo et al. (2017) reported that most of the 2.1PN-derived blastocysts were diploid by preimplantation genetic testing for aneuploidy (PGT-A), including single-nucleotide polymorphisms (SNPs) analysis. Thus, the treatment with 2.1 PN zygotes should be performed with chromosome testing. In Japan, where PGT-A is not available in principle, 2.1PN zygotes are rarely used in the embryo transfer. On the other hand, the size of the micro pronucleus in 2.1PN zygotes has not been clearly defined, and it is difficult to determine differences between 2.1PN and 3PN zygotes. Study design, size, duration The study was performed retrospectively on 2463 cycles of in vitro fertilization (IVF) conducted at our clinic between August 2020 and December 2021. A total of 3073 embryos underwent conventional-IVF (c-IVF) or intracytoplasmic sperm injection (ICSI) and were cultured in the time-lapse incubator, of which 221 zygotes with three pronuclei were used in the study. Participants/materials, setting, methods The diameter of the three PNs at one hour before syngamy from time-lapse images; 2.1 PN and 3PN zygotes were classified in the report by Capalbo et al. (2017). The age of the patients and the method of insemination between the groups were compared, and the diameter of the micro PN was analysed. Moreover, logistic regression analysis was performed to investigate the predictor of 2.1PN zygotes from the morphological characteristics of oocytes at ICSI. Main results and the role of chance The mean age of each patient was 42.9 years for 2.1PN zygotes and 39.8 years for 3PN zygotes, significantly higher for 2.1PN zygotes (P =0.003). On the other hand, when comparing the stage of oocyte maturation at the time of oocyte retrieval, there was no significant difference (P =0.749). According to the insemination method, the incidence of 2.1PN zygotes was significantly higher in ICSI (including rescue-ICSI) compared to c-IVF: 32.9% [95%CI: 22.5-44.6%] vs 2.4% [95%CI: 0.1-12.9%] (P Limitations, reasons for caution In this study, we have not investigated whether 2.1 PN zygotes become blastocysts. It will be necessary to further examine the criteria for 2.1PN along with chromosome testing to investigate the use of 2.1PN-derived blastocysts. Wider implications of the findings A pronucleus of less than 15 μm in diameter can be considered a micro PN. Compared to 3PN zygotes, 2.1PN zygotes were more frequently observed in older patients and in ICSI-derived zygotes. However, it is difficult to predict the incidence of 2.1PN zygotes from the oocytes’ morphological characteristics at ICSI. Trial registration number not applicable

Glass with embedded metal and sulfides (GEMS) is a major component of chondritic porous interplanetary dust particles. Although GEMS is one of the most primitive components in the Solar System, its formation process and conditions have not been constrained. We performed condensation experiments of gases in the system of Mg–Si–O (MgSiO3 composition) and of the S-free CI chondritic composition (Si–Mg–Fe–Na–Al–Ca–Ni–O system) in induction thermal plasma equipment. Amorphous Mg-silicate particles condensed in the experiments of the Mg–Si–O system, and their grain size distribution depended on the experimental conditions (mainly partial pressure of SiO). In the CI chondritic composition experiments, irregularly shaped amorphous silicate particles of less than a few hundred nanometers embedded with multiple Fe–Ni nanoparticles of ≤20 nm were successfully synthesized. These characteristics are very similar to those of GEMS, except for the presence of FeSi instead of sulfide grains. We propose that the condensation of amorphous silicate grains smaller than a few tens of nanometers and with metallic cores, followed by coagulation, could be the precursor material that forms GEMS prior to sulfidation.

Study question The aim of this study is to analyse the association between blastocyst diameter and TVs development, and to examine the efficacy of AH. Summary answer Blastocysts with a diameter of more than 170 μm leads to high incidence of TVs and AH applied from the incidence should be effective. What is known already TVs are protrusion of trophectoderm cells often observed in expanding blastocyst stages. TVs can be observed in expanding blastocysts regardless of Intracytoplasmic sperm injection (ICSI) and Conventional-IVF (C-IVF), when the internal pressure of blastocysts increase. The rate of TVs incidence in blastocysts inseminated by ICSI is higher than that by C-IVF, due to penetration of the needle into the zona pellucida. Moreover, it has been reported that TVs may inhibit blastocyst hatching. However, the developmental timing of TVs is still unclear, and there is no study that has analysed the association between blastocyst diameter and the incidence of TVs. Study design, size, duration 1) Diameters and TVs incidence of blastocysts by ICSI and C-IVF were measured, and the cut-off value and the area under the curve (AUC) of the receiver operating characteristic (ROC) curve were calculated to estimate the timing of TV incidence. 2) We analysed the clinical pregnancy rates of blastocysts with TVs treated by AH compared to those of blastocysts by C-IVF not subjected to AH. Participants/materials, setting, methods This study included 821 transferred frozen blastocysts ranging from March 2018 to November 2019. The embryos were cultured in a dry incubator after insemination by ICSI or C-IVF. Blastocyst freezing conditions were set at day5 to day7 with a diameter of more than 150 μm in inner diameter of zona pellucida, and this was measured before freezing. The ROC curve was performed using EZR statistical analysis software. Main results and the role of chance 1) The incidence of TVs in blastocysts by ICSI and C-IVF was 27.5% (117/424) and 14.6% (58/397) respectively. The rate of the incidence of TVs in blastocysts inseminated by ICSI and C-IVF; 8.6% (12/140) and 0.95% (1/105) in 150–159 μm, 12.7% (14/110) and 8.2% (6/73) in 160–169 μm, 40.6% (28/69) and 10.5% (6/57) in 170–179 μm, 55.6% (30/54) and 25.5% (13/51) in 180–189 μm, 66.7% (20/30) and 35.7% (10/28) in 190–199 μm, and 68.4% (13/19) and 26.8% (22/82) in the diameter of more than 200 μm. The cut-off value of the ROC curve was respectively 170 μm (sensitivity 78.6% and specificity 73.0%) and 176 μm (sensitivity 84.5% and specificity 59.6%) in the diameter; the AUC was 0.8 [95%CI:0.752–0.848] and 0.74 [95%CI:0.687–0.793] respectively. 2) The clinical pregnancy rate of TVs blastocyst vs C-IVF blastocyst was 52.7% (88/167) vs 57.8% (37/64) respectively. There is no significant difference between the two clinical pregnancy rates (P = 0.556). Limitations, reasons for caution The findings of this study have to be seen in light of some limitations. Since this study aimed to analyse the incidence of TVs based on blastocyst size, we did not take into account the grade according to the Gardner classification and the number of trophectoderm cells. Wider implications of the findings: Blastocysts inseminated by ICSI and C-IVF were highly likely to have TVs above 170 μm and 176 μm respectively. The clinical pregnancy rates of the blastocyst with TV treated by AH was similar to those of the C-IVF blastocyst. Trial registration number Not applicable

Study question Why do multinucleated blastomeres appear at high frequency in two-cell-stage embryos in humans? Summary answer Failure in microtubule assembly during the first mitotic spindle body formation by sperm centrosome-dependent microtubule organising centres (MTOCs) may lead to chromosomal instability. What is known already Unlike that in mice, multinucleated blastomeres appear at high frequency in two-cell-stage embryos in humans. However, the underlying mechanism remains elusive. In mice, multiple acentriolar MTOCs appear around the male and female pronuclei after pronuclear disappearance and contribute to dual-spindle formation, engulfing each parental chromosome. This spindle formation may ensure an error-free division, keeping the chromosomes stable during the first cleavage, as observed in mice, but it is unclear whether a similar mechanism exists in humans. Study design, size, duration To examine how sperm centrosomes contribute to MTOC formation in humans, two types of 3PN zygotes derived fromeither conventional in vitro fertilization (c-IVF, n = 30) or intracytoplasmic sperm injection (ICSI, n = 10) were used. The zygotes were collected from October 2018 to January 2020. MTOC and mitotic spindle formation at consecutive stages of development during the first cleavage were analysed under static and dynamic conditions using immunofluorescence assay and fluorescent live-cell imaging. Participants/materials, setting, methods Under ethics approval, 3PN zygotes were donated by infertile couples undergoing c-IVF or ICSI cycles at the Yamashita Shonan Yume Clinic in Japan. All participants provided informed consent. Immunofluorescence assay was performed using antibodies against α-tubulin, pericentrin, and H3K9me3 after fixation with MTSB-XF solution. Fluorescent live-cell imaging was performed using TagGFP2-H2B mRNA (chromosome marker) and FusionRed-MAP4 mRNA (microtubule marker). Main results and the role of chance Immunofluorescence revealed that while 3PN zygotes derived from c-IVF showed four pericentrin dots, those derived from ICSI exhibited two pericentrin dots. In pro-metaphase, an independent group of chromosomes derived from each pronucleus and MTOCs were formed by the sperm centrosome at the core. Microtubules from each MTOC extended toward the chromosomes in the early metaphase; a quadrupolar spindle was formed in the c-IVF-derived zygotes, and a bipolar spindle was formed in the ICSI-derived zygotes by the MTOCs at the zygote apex after chromosome alignment. In pro-metaphase, the microtubules extended from the MTOCs to the nearest chromosome. Since microtubule assembly was found on oocyte-derived chromosomes, we hypothesised that whether a chromosome is surrounded by microtubules depends on the location of the MTOCs, irrespective of its origin. Live-cell imaging of histone H2B and MAP4 revealed that four MTOCs appeared around the three pronuclei just before the disappearance of the pronuclear membrane; microtubules then extended from the MTOCs toward the chromosomes, beginning to form a mitotic spindle as the chromosomes moved to the centre of the oocyte. Interestingly, one of the three assembled chromosome groups showed no microtubule assembly in the pro-metaphase. Similar results were obtained in all six 3PN zygotes subjected. Limitations, reasons for caution We demonstrated the high risk of developing bare chromosomes not surrounded by microtubules during the formation of the first mitotic spindle, using human tripronuclear zygotes. However, owing to unavailability of normal fertilized oocytes for this study because of the clinical use, we were unable to confirm this in normal zygotes. Wider implications of the findings Although two sperm centrosome-dependent MTOCs are expected to be formed in normal fertilized oocytes, these MTOCs are not sufficient to completely enclose physically separated female and male chromosomes with the microtubules. This explains the high frequency of zygotic division errors that lead to unstable human chromosomes. Trial registration number not applicable

Glass with embedded metal and sulfides (GEMS), the major components of chondritic-porous interplanetary dust particles (CP-IDPs), is one of the most primitive materials in the Solar System and may be analogous to the amorphous silicate dust observed in various astronomical environments. Mineralogical characteristics of GEMS should reflect their formation process and condition. In this study, synthetic experiments in the sulfur-bearing system of Fe–Mg–Si–O–S were performed with a systematic change in redox conditions using thermal plasma systems to reproduce the mineralogy and textures of GEMS. The resulting condensates were composed of amorphous silicates with Fe-bearing nano-inclusions. The Fe content and texture in the amorphous silicates as well as the mineral phases of the nanoparticles correlate with redox conditions. Fe dissolved in the amorphous silicate as FeO in oxidizing conditions formed Fe-metal nanoparticles in intermediate redox conditions, and gupeiite (Fe3 Si) nanoparticles in reducing conditions. In intermediate to reducing redox conditions, Fe-poor amorphous silicate formed a biphasic texture with Mg- and Si-rich regions, indicating liquid immiscibility during the melt phase. Most Fe-metal particles were surrounded by FeS and formed on the surface of amorphous silicate grains. Condensates produced in intermediate to slightly reducing redox conditions resemble GEMS in that they have similar mineral assemblages and chemical compositions to amorphous silicate, except that the Fe-metal grains are absent from the interior of the amorphous silicate grains. This textural difference can be explained by the sulfidation at high temperatures in this study, in contrast to sulfidation occurring at low temperatures in the presence of H2 in natural GEMS formation. Based on the two-liquid structures observed in the experimental products and in GEMS, also recognized in infrared spectra, we propose that GEMS condensed as silicate melt under limited redox conditions followed by incorporation of multiple metal grains into the silicate melt or by aggregation of coreshell structured grains before sulfidation of the metallic iron. Condensates produced in oxidizing conditions are similar to GEMS-like material in the matrices of primitive carbonaceous chondrite meteorites, indicating the possibility that they form by direct condensation from nebula gas in relatively oxidizing conditions compared to GEMS.

Pattern collapse of nano-structures during the wet cleaning process is one of the main problems which leads to poor device yield. In general, aspect ratio (AR) is often used as the indicator for determining the likelihood of pattern collapse occurrence, because high aspect ratio structures tend to collapse more easily. However, pattern collapse is also influenced by flexural rigidity of the structures, material, and shape. Therefore, AR lacks versatility in comparing different structures and material. We propose “$\gamma_{PC}$” as the substitute parameter for aspect ratio. In this paper, we indicate with experimental data that $\gamma_{PC}$ is more accurate than aspect ratio, and can be used to quantitatively determine the pattern collapse prevention performance of dry technologies.}

From the viewpoint of preserving the global environment and making efficient use of resources, the use of by-products in the field of construction to reduce environmental impact has become a social requirement. While by-products such as ground granulated blast furnace slag and fly ash have the effect of improving the quality of concrete and have long been used as blending components in blended cement, their use as mineral admixtures has been limited and more active use is desirable. The quality of ground granulated blast furnace slag and fly ash as concrete materials is covered by JIS, Japan Society of Civil Engineers guidelines and Architectural Institute of Japan guidelines, and the conditions for their use as mineral admixtures have been established, but it cannot be said that they are being widely used at present. This report sorts the issues that need to be addressed for the active use of these by-products for concrete admixture and proposes measures to expand their use.地球環境に対する配慮や資源の有効利用の観点からは，建設分野においても環境負荷の低減に向けた副産物の活用が社会的な要請となっている。高炉スラグ微粉末やフライアッシュなどの副産物は，コンクリートの品質を改善する効果があり，混合セメントの「混合材」として古くから用いられている一方，「混和材」としての利用は限定的で，より積極的な利用が望まれている。高炉スラグ微粉末やフライアッシュは，コンクリート用材料としての品質がJIS，土木学会や日本建築学会の施工指針等に取り上げられ，混和材として利用できる条件は整っているが，現状では広く使用されているとはいい難い。この報告では，これらの副産物をコンクリート用混和材として積極的に利用するための課題を整理し，適用拡大に向けた方策を提案している。

We developed an X-ray pinhole camera using a radio-isotope source that emits only X-rays.We investigated the performance of this system using a 55Fe source with phantom samples. We then applied it to investigate the movement of a 55Fe tracer in Japanese mustard spinach. We obtained X-ray images of the 55Fe tracer in the spinach samples, and found that 55Fe accumulated in the plant.

To evaluate the high-resolution computed tomography (CT) findings of primary lung cancer with cavitation and compare the findings in adenocarcinoma and squamous cell carcinoma.The high-resolution CT findings of tumours with cavitation were retrospectively evaluated in 60 patients. Forty-seven of the lesions were diagnosed as adenocarcinomas; 13 were diagnosed as squamous cell carcinomas. The diameters of the tumour and cavity, the maximum thickness of the cavity wall, shape of the cavity wall, the number of cavities, and the presence of ground-glass opacity, bronchial obstruction, intratumoural bronchiectasis, emphysema, and honeycombing were evaluated. The mechanisms of cavity formation were examined according to the pathological features.The maximum thickness of the cavity wall was significantly greater in squamous cell carcinomas than in adenocarcinomas (p=0.002). Ground-glass opacity and intratumoural bronchiectasis were significantly more common in adenocarcinomas than in squamous cell carcinomas (p0.001 and p=0.040, respectively). Regarding the pathological findings, intratumoural bronchiectasis with or without alveolar wall destruction contributed to a significant difference between adenocarcinoma and squamous cell carcinoma (p0.001; odds ratio [OR], 20.35; 95% confidence interval [CI], 3.87-107.10).The cavity wall tends to be thicker in squamous cell carcinomas than in adenocarcinomas. The presence of ground-glass opacity and intratumoural bronchiectasis is strongly suggestive of adenocarcinoma.

The self-accommodation morphologies of B19′ martensite in Ti–Ni alloys have been investigated by optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Twelve pairs of minimum units consisting of two habit plane variants (HPVs) with V-shaped morphology connected to a B19′ type I variant accommodation twin were observed. Three types of self-accommodation morphologies, based on the V-shaped minimum unit, developed around one of the {111}B2 traces, which were triangular, rhombic and hexangular and consisted of three, four and six HPVs, respectively. In addition, the variant selection rule and the number of possible HPV combinations in each of these self-accommodation morphologies are discussed.

Competition between the invariant plane (IP) condition at the habit plane, the twin orientation relation (OR) and the kinematic compatibility (KC) at the junction plane (JP) of self-accommodated B19′ martensite in Ti–Ni was investigated via the geometrically nonlinear theory to understand the habit plane variant (HPV) clusters presented in Parts I and II of this work. As the IP condition cannot be satisfied simultaneously with KC, an additional rotation Q is necessary to form compatible JPs for all HPV pairs. The rotation J necessary to form the exact twin OR between the major correspondence variants (CVs) in each HPV was also examined. The observed HPV cluster was not the cluster with the smallest Q but the one satisfying Q = J with a { 1}B19′ type I twin at JP. Both Q and J are crucial to understanding the various HPV clusters in realistic transformations. Finally, a scheme for the ideal HPV cluster composed of six HPVs is also proposed.

Four characteristic interface microstructures between habit plane variants (HPVs) in the self-accommodation morphologies of B19′ martensite in Ti–Ni alloys have been investigated by scanning transmission electron microscopy (STEM). The straight interface of a B19′ type I twin is present at interface I. The relaxation of the transformation strain at interface II is achieved by a volume reduction of the minor correspondence variants (CVs) in the relevant habit plane variants (HPVs). The relaxation of the transformation strain at interface III is mainly due to the formation of a B19′ type I twin between the two major CVs. Subsequently, local strain around the tips of the minor CVs perpendicular to the interface is released by the formation of micro-twins with the ⟨011⟩B19′ type II and/or B19′ type I relation. The major and minor CVs in each HPV are alternately connected through fine variants with the B19′ type I twin relation parallel to interface IV. The results are compared with macroscopic observations an...

本報は，レディーミクストコンクリート工場の調査と，工場に常備された骨材を用いたコンクリートの品質評価試験を実施した内容である。工場調査では，工場の標準配合における単位水量，単位セメント量および水セメント比の実態を示した。また，品質評価試験では，圧縮強度，静弾性係数，自己収縮，乾燥収縮および熱膨張係数を取り上げ，それらの物性に及ぼす骨材の影響を示した。それらの調査および試験の結果に対して，施工者の立場から評価を行い，施工上の留意点を述べた。

Refueling by hydrogen ice pellet injection has been studied in various plasmas. The research of pellet ablation related to refueling is very important object. In the central-cell plasma of tandem mirror GAMMA 10, we measured the position of pellet ablation by vertical and horizontal arrays of Ha detectors and a high-speed CMOS camera. We found that the penetration depths with applying electron cyclotron heating (ECH) is shorter than that without ECH. It suggests that the pellet ablation is strongly affected by warm electrons produced with ECH. Moreover, we investigated the effects of neutral beam injection (NBI) to the pellet ablation, which showed the pellet ablation in the situation of higher density plasma. The pellets penetrate through the plasma without applying ECH or NBI. We observed the pellet ablation at each position by using vertical and horizontal arrays of Ha detectors and a high-speed CMOS camera with the interference filter.

Detailed behavior of plasmas has been investigated in the course of an optimization phase of wall conditioning in the central-cell of GAMMA 10 tandem mirror. The results are described based on the visible image measurements using CCD camera together with Hα line-emission measurements in the central-cell. Three limiters are installed in the central-cell and the behavior of the plasmas near the each limiter is precisely observed in response to electron cyclotron heating (ECH) for potential formation. In an early stage of wall conditioning in GAMMA 10, plasma parameters obtained in standard hot ion mode plasmas are compared in cases of sustained plasma in ECH pulses and of collapsed one simultaneously with ECH. Dependence of gas puffing from the mirror throat in the central cell and of the diameter of limiters is also investigated on the plasma behavior in ECH. From the measured results, it is recognized that a significant upward shift of the plasma column and imbalance of the Hα intensity between east and west Iris-limiters cause the plasma collapse in ECH. A systematic analysis of the dependence on plasma durability in the number of wall conditioning shots, the position of the plasma just before the ECH injection and suitable quantity of gas puffing is necessary for stably sustaining the plasma during potential formation by ECH.

FePt films were deposited by a low energy sputtering method, i.e., gas flow sputtering, without heating the substrate. The effects of annealing on the L10 order parameter, morphology, and magnetic properties of the films were studied. The order parameter increased significantly after annealing at 413°C; the order parameter of a 76-nm-thick film was found to be 0.84. The coercivity of the film was 15.6 kOe, which was in agreement with the high order parameter. Scanning electron microscopy observations showed that the ordering in the films proceeded with the growth of grains. The XRD pattern of an unannealed thick (950 nm) film showed a 110 superstructure peak. The small grain size in the as-deposited film and the existence of nuclei of the L10 phase may play key roles in inducing the ordering at a relatively low temperature. These factors may promote discontinuous ordering, wherein ordering proceeds with grain boundary diffusion and growth of grains with an L10 structure.

Transport of neutral particles in a non-axisymmetric plasma device is described based on a Monte-Carlo simulation and of Dα line-emission measurements. DEGAS three-dimensional (3-D) Monte-Carlo code for neutral transport simulation has been applied to a helical-axis heliotron device, Heliotron J. In a whole area of Heliotron J vacuum vessel, a detailed 3-D mesh structure for the simulation was constructed especially for the precise investigation of particle transport in the toroidal direction. In this mesh model, a carbon target is also modeled in the simulation space, and the simulation has been carried out for the target insertion experiments in Heliotron J. Simulation results were compared with the results obtained from two-dimensional image captured with a CCD camera viewing the top surface of the carbon target. The compared results indicated that the particle source caused by the carbon target is thought to be much more localized than expected one from the Dα image around the target. Particle transport to the toroidal direction was also discussed based on the 3-D simulation. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The Japan Arteriosclerosis Longitudinal Study-Existing Cohorts Combine (JALS-ECC) is a pooled study based on individual participant data from existing prospective cohort studies in Japan. Its purpose was to consider associations between risk factors and cardiovascular disease (CVD) outcomes, as well as differences between subgroups, defined by age, gender or geographical region, which could not be detected in the smaller samples.Individual records for 66,691 participants in 21 cohort studies were pooled, accounting for a total of 575,628 person-years. From this data, there were 409 deaths attributed to stroke and 169 deaths attributed to coronary heart disease (CHD). Total stroke and CHD events were 1,478 and 178, respectively. Of the 1,424 total stroke events with a reported stroke subtype, 975 were classified as ischemic, 267 as hemorrhagic, and 178 as subarachnoid hemorrhage.The JALS-ECC collected data from existing cohort studies covering a diverse Japanese population, which has provided information about the effects of modifiable factors on the risks of the CVD. Such information should provide a reliable basis for establishing prevention strategies.

The small angle neutron scattering diffraction patterns from the flux line lattice state in the layered hexagonal superconductor CaAlSi are observed. Under an applied magnetic field (H) parallel to the crystalline c-axis, a hexagonal vortex structure is observed over the entire temperature/field regions. On the other hand, the vortex configuration under H∥a shows an ellipsoidal arrangement of the first-order Bragg peaks due to the anisotropic penetration depth. It was inferred from these results that the vortex state characterized by penetration depth and coherence length in CaAlSi may be described by that of anisotropic uniaxial superconductor using London theory.

Detailed results of edge plasma and neutral particle behavior are described in the gas puff imaging experiments performed in the GAMMA 10 tandem mirror for the first time. Visible imaging measurement by using a high-speed camera (Ultima-SE, Photron Inc.) was recently performed in the central-cell midplane of GAMMA 10. In the standard plasma discharge heated by ICRF wave, a short gas puff of hydrogen (3 ms) was carried out and the time evolution of light emission was visualized precisely. It was found that the time evolution of the emission cloud was similar to that of Hα line intensity measured nearby and was localized close to the gas puff port. Asymmetry in diffusion of the emission cloud is observed radial and axial direction of plasma column in the central-cell. This localization phenomenon of neutrals is qualitatively well explained by a fully 3-dimensional simulation using DEGAS neutral particle transport code.

A blimp-type unmanned aerial vehicle (BUAV) maintains its longitudinal motion using buoyancy provided by the air around it. This means the density of a BUAV equals that of the surrounding air. Because of this, the motion of a BUAV is seriously affected by flow disturbances, whose distribution is usually non-uniform and unknown. In addition, the inertia in the heading motion is very large. There is also a strict limitation on the weight of equipment in a BUAV, so most BUAVs are so-called under-actuated robots. From this situation, it can be said that the motion planning of the BUAV considering the stochastic property of the disturbance is needed for obstacle avoidance. In this paper, we propose an approach to the motion planning of a BUAV via the application of Markov decision process (MDP). The proposed approach consists of a method to prepare a discrete MDP model of the BUAV motion and a method to maintain the effect of the unknown wind on the BUAV’s motion. A dynamical simulation of a BUAV in an environment with wind disturbance shows high performance of the proposed method.

Behavior of edge plasma and neutral particles are described based on visible measurement by using high-speed camera performed in the GAMMA 10 tandem mirror for the first time. In the central-cell midplane of GAMMA 10, two high-speed cameras (Ultima-SE, Photron Inc. and MEMRECAM fx-K4, NAC Inc.) were mounted and detailed time behavior of visible light emission from the plasma was investigated. In the standard plasma discharges heated by ion cyclotron range of frequency (ICRF) wave, a short gas puffing of hydrogen (3 ms) close to the central-cell midplane was carried out to illuminate the plasma periphery and the time evolution of visible light emission from the gas cloud was captured precisely. The time behavior of the emission cloud localized near the gas puff port was found to be similar to that of Ha line intensity measured nearby. The light emission on the central-cell limiter accompanied by central electron cyclotron heating (c-ECH) showed a rotation in the direction of the electron diamagnetic drift. the light emission also indicates another rotation mechanism, such as ExB drift at a plasma collapse. Fully three-dimensional neutral transport simulation using a Monte-Carlo code DEGAS is applied to gas puff imaging experiment and the simulation results qualitatively explained the experimental result.

Objective:Our aim was to determine if stapes surgery is useful for treating inflammatory ear diseases.Materials and methods:Thirteen patients underwent single-stage or staged surgery for stapes fixation due to tympanosclerosis alone or with cholesteatoma. Operative criteria were: no tympanic membrane retraction, perforation or adhesion; middle-ear cavity with aeration >1 year; a fixed stapes. Computed tomography was used to analyse the relation between operative success and pre-operative pneumatisation.Results:Success rate at six months was 75 per cent. Hearing results were stable with little deterioration and no complications. Patients with poor pneumatisation had good results (with improved air–bone gap) only after staged surgery. Well-aerated ears heard better even with single-stage surgery.Conclusions:Pre-operative computed tomography and intra-operative findings are necessary to determine the pneumatisation status of tympanic mastoid cavities. If criteria approved, poorly pneumatised patients underwent staged surgery. Stapedectomy achieved good hearing results for inflammatory middle-ear disease with stapes fixation.

Oxide deposition followed by high-temperature annealing in N2O has been investigated to improve the quality of 4H-SiC MOS structures. Annealing of deposited oxides in N2O at 1300oC significantly enhances the breakdown strength and decreases the interface state density to 3x1011 cm-2eV-1 at EC – 0.2 eV. As a result, high channel mobility of 34 cm2/Vs and 52 cm2/Vs has been attained for inversion-type MOSFETs fabricated on 4H-SiC(0001)Si and (000-1)C faces, respectively. The channel mobility shows a maximum when the increase of oxide thickness during N2O annealing is approximately 5 nm. A lateral RESURF MOSFET with gate oxides formed by the proposed process has blocked 1450 V and showed a low on-resistance of 75 mcm2, which is one of the best performances among lateral SiC MOSFETs reported.

金沢大学理工研究域環境デザイン学系, The bearing capacity of an open-ended pipe pile consists of outer shaft resistance, toe resistance and soil plug resistance (inner shaft resistance). The soil plug capacity is thought to be largely controlled by height and stress states of soil plug that is formed inside the pile during installation process. However, these aspects have not been fully clarified. In this paper, parametric study on push-up loading of soil plug was carried out using three-dimensional discrete element method for the first step to investigate the bearing mechanism of open-ended pipe pile. Influence of dilatancy of sand and the soil plug height was focused. © 2006 Taylor & Francis Group.

This paper addresses a thermal gas-flow simulation in gas circuit-breaker (GCB) chambers, introducing SF/sub 6/ gas constants up to a pressure of 10 MPa and to a temperature of 30 000 K. In the simulation, moving parts, such as nozzle, movable arcing contact, and operating rod, are moved with the opening motion of GCB to see if different results are produced from the conventional simulation method, in which fixed parts in the real GCB are moved. As a result, as far as the pressure profile in the puffer chamber is concerned, it is confirmed that this simulation method can produce better results than the conventional method for the hybrid-puffer-type chamber.

A multi-degree-of-freedom (DOF) ultrasonic motor can rotate in three DOFs and does not generate noise. In addition, with an appropriate preloading mechanism, it can generate high torque for its size. The multi-DOF ultrasonic motor is, therefore, anticipated for use as a servomotor in the next generation of robots. However, for several reasons, there have been few applications of multi-DOF ultrasonic motors. One reason is the difficulty in designing a proper preloading mechanism for the motor and the limitation of the size of the stators. Another is the difficulty in developing a control algorithm, due to the motor's complex and changing dynamical characteristics, and the serious jaggy motion caused by its very quick response. This paper proposes a preloading mechanism and control algorithm for a multi-DOF ultrasonic motor, considering the motor's application to an actual auditory tele-existence robot, TeleHead. TeleHead is an elaborate dummy head robot that has a 3-DOF neck mechanism. The proposed methods achieve smooth and fast multi-DOF rotating motion of the dummy head with little time delay. In the preloading method, tensioned springs generate high preloading force and make up for the lack of torque by compensating for the resistance torque generated by the inclining motion of the dummy head. In the control algorithm, high-DOF motion is managed by high-frequency switching of the rotating axis, and smooth and quick trajectory tracking motion is achieved by introducing feed-forward control using an inverse model, with multiresolution acquired by feedback-error learning. Experimental results verify the high performance of these methods.

Screw’s are widely used because of their ease of use and very high joint force. Screws can be tightened very easily using plus- or minus screwdrivers. However, the cross- or minus-shaped recess on the screwhead causes a lot of problems. First, screws can be too easily loosened by screwdrivers, which means it becomes very easy to dismantle parts that should not be dismantled. Second, the recess makes a machine less aesthetically pleasing. Third, many screwdrivers of different diameter must be available. Fourth, if the recess is damaged, it becomes difficult or impossible to tighten or loosen the screw. To solve these problems, we propose a recessless screw. Recessless screw provides ultimate tamper-resistance. The proposed screwdriver uses piezoelectric cells to tighten or loosen recessless screws. Piezoelectric cells vibrate ultrasonically, generating rotation and tightening torque. The principle of the proposed screwdriver is examined by experiments whose results show the high potential of the piezoelectric screwdriver.

Optimum dose designing for 4H-SiC (0001) two-zone RESURF MOSFETs is investigated by device simulation and fabrication. Simulated results suggest that negative charge at the SiC/SiO2 interface significantly influences breakdown voltage. Simulation has also showed that breakdown voltage strongly depends on LDD (Lightly-Doped Drain) dose. The dose dependencies of the breakdown voltage experimentally obtained are in good agreement with the device simulation. A RESURF MOSFET, processed by N2O oxidation, with an optimized dose blocks 1080V and has a low on-resistance of 79 mcm2 at a gate oxide field of 3.0 MV/cm, which is the best 4H-SiC RESURF MOSFET ever reported.