251 research outputs found

    Depositional environments of the Katsuta Group, eastern Tsuyama Basin, Southwest Japan

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    The Miocene Katauta Group of the Syohoku-cho area is subdivides into 6 members ; The Uetsuki Conglomerate Member, Nara Sandy Mudstone Member, Tai Gravelly Sandstone Member, Takatori Conglomerate Member, Ayabe Mudstone Member and Maruyama Mutstone Member from bottom to top. The unconformity between Miocene deposits and basement rocks in this area was traced to obtain geometry of the Miocene basin. Contour maps of the bases of the Miocene Yoshino Formation and Takakura Formation indicate paleo-topography. The obtained topography demonstrates a valley, which flowed to north-west, and a few islands and bays. It indicates that these Miocene successuions were deposited in the topography which resemble to the present Seto Inland

    Real-time Trading System based on Selections of Potentially Profitable, Uncorrelated, and Balanced Stocks by NP-hard Combinatorial Optimization

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    Financial portfolio construction problems are often formulated as quadratic and discrete (combinatorial) optimization that belong to the nondeterministic polynomial time (NP)-hard class in computational complexity theory. Ising machines are hardware devices that work in quantum-mechanical/quantum-inspired principles for quickly solving NP-hard optimization problems, which potentially enable making trading decisions based on NP-hard optimization in the time constraints for high-speed trading strategies. Here we report a real-time stock trading system that determines long(buying)/short(selling) positions through NP-hard portfolio optimization for improving the Sharpe ratio using an embedded Ising machine based on a quantum-inspired algorithm called simulated bifurcation. The Ising machine selects a balanced (delta-neutral) group of stocks from an NN-stock universe according to an objective function involving maximizing instantaneous expected returns defined as deviations from volume-weighted average prices and minimizing the summation of statistical correlation factors (for diversification). It has been demonstrated in the Tokyo Stock Exchange that the trading strategy based on NP-hard portfolio optimization for NN=128 is executable with the FPGA (field-programmable gate array)-based trading system with a response latency of 164 μ\mus.Comment: 12 pages, 5 figures. arXiv admin note: text overlap with arXiv:2307.0592

    Numerical study of air-entraining and submerged vortices in a pump sump

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    Numerical detection of harmful vortices in pump sumps, such as an air-entraining vortex (AEV) and a submerged vortex (SMV), is crucially important to develop the drain pump machinery. We performed numerical simulations of the benchmark experiments of the pump sump conducted by Matsui et al. (2006 and 2016) using the OpenFOAM and compared the simulation results with the experimental data considering the effects of turbulence model, grid density and detection method of the vortices. We studied the threshold of the gas-liquid volume fraction of the VOF method and the second invariant of velocity gradient tensor to identify AEV and SMV. The methods proposed in the present paper were found to be very effective for the detection of the vortices, and the simulation results by RANS with the SST k-omega model successfully reproduced the experimental data. LES with the Smagorinsky model, however, was sensitive to the grid system and difficult to reproduce the experimental data even for the finest grid system having 3.7 million cells in the present study

    Ten Initial Cases of Peroral Endoscopic Myotomy for Treatment of Esophageal Motility Disorders at Okayama University Hospital

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    Peroral endoscopic myotomy (POEM) for treatment of esophageal motility disorders has recently been reported to be highly effective and less invasive than other treatment. POEM was recently introduced in Okayama University Hospital under the supervision of a physician from a high-volume center. To verify the safety and efficacy of POEM during its introduction in our institution. We examined 10 cases in whom POEM was performed between January 2016 and April 2017. The patients included 7 men and 3 women, with a median age (range) of 49 years (17-74) and median symptom duration of 6 years (1-21). Seven patients had a straight esophagus, and the remaining 3 had a sigmoid esophagus. According to the Chicago classification, 6 patients were diagnosed with type I achalasia, 2 with type II achalasia, and 2 with distal esophagus spasm. Treatment outcomes and adverse events were evaluated. Treatment success was defined as a > 3 decrease in Eckardt score or a score of <3 at the time of discharge. The treatment success rate was 90%, with the average Eckardt score decreasing significantly, from 4.7 to 0.9 (p<0.05). No mucosal perforation, severe infection, mediastinitis, severe bleeding, or gastroesophageal reflux occurred intraoperatively or postoperatively. POEM was introduced to Okayama University Hospital, and the first 10 cases were accomplished safely and effectively under the supervision of an expert physician from a high-volume center

    Fabrication of a 64-Pixel TES Microcalorimeter Array with Iron Absorbers Uniquely Designed for 14.4-keV Solar Axion Search

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    If a hypothetical elementary particle called an axion exists, to solve the strong CP problem, a 57Fe nucleus in the solar core could emit a 14.4-keV monochromatic axion through the M1 transition. If such axions are once more transformed into photons by a 57Fe absorber, a transition edge sensor (TES) X-ray microcalorimeter should be able to detect them efficiently. We have designed and fabricated a dedicated 64-pixel TES array with iron absorbers for the solar axion search. In order to decrease the effect of iron magnetization on spectroscopic performance, the iron absorber is placed next to the TES while maintaining a certain distance. A gold thermal transfer strap connects them. We have accomplished the electroplating of gold straps with high thermal conductivity. The residual resistivity ratio (RRR) was over 23, more than eight times higher than a previous evaporated strap. In addition, we successfully electroplated pure-iron films of more than a few micrometers in thickness for absorbers and a fabricated 64-pixel TES calorimeter structure.Comment: 5 pages, 5 figures, published in IEEE Transactions on Applied Superconductivity on 8 March 202
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