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Journal of Applied Mathematics and Physics 2021年第11期9卷 2669-2697页

作者： eiji toma Yoshihiro Ito National Institute of Technology Tomakomai College Tomakomai Japan

A water rocket is a rocket system that obtains thrust by injecting water with compressed air of up to about 8 atmospheres. It is usually manufactured using a pressure-resistant PET bottle. The mechanical elements and principles contained in the water rocket have much in common with the actual small rocket system, and are suitable as educational and research teaching materials in the field of mechanics. Especially in the field of disaster prevention and mitigation, the use of water rockets is being researched and developed as a rescue tool in the event of a flood or earthquake as a disaster countermeasure. However, since the water rocket is a flying object based on the mechanical principle, it is important to ensure the accuracy and stability of the flight path. In this paper, a mechanical simulator is developed with a numerical calculation program based on the mechanical consideration of water rocket flight performance. In addition, the correlation between the flight distance obtained in the simulation and the estimated flight distance is analyzed by applying a multivariate analysis method and verifying the validity of the flight distance calculated from the result. Based on the verification results, we will apply a statistical optimization method to approach the optimization of flight stability performance conditions for water rockets.

关键词： Flying Principle Multivariate Analysis T Method Robust Parameter Design Flight Stability Energetic SN Ratio

The Method for Optimum Estimation of COVID-19 Variant Type Virus Infection Status Analysis by the Multivariate Analysis Considering the Environmental Variability Impact in Japan

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Journal of Applied Mathematics and Physics 2022年第2期10卷 425-448页

作者： eiji toma Yukinori Kobayashi National Institute of Technology Tomakomai College Tomakomai Japan

Currently, the estimated value of the effective reproduction number (ERN), which is an index for grasping the COVID-19 infection status, is used for important planning and evaluation of infection prevention measures. Since ERN in the Sequential SIR model fluctuates in multiple dimensions due to changes in the surrounding environment, it is difficult to set the appropriate accuracy of the uncertainty region of the estimated data. The challenge in this study is to build a mathematical model of infectious disease according to the characteristics and data characteristics of the infectious disease and select an appropriate estimation method. Highly accurate quantitative research that analyzes the validity of “how infectious diseases prevail” from an academic point of view is the key to prediction and estimation in appropriate infection situation analysis. In this study, we adopted a statistical multivariate analysis method (T method) that enables evaluation and prediction of important factors related to ERN estimation and analysis of phenomena that change in real time (time series analysis). It was clarified that it is possible to estimate with higher accuracy by applying the T method to the estimated value of ERN by the current SIR mathematical model.

关键词： COVID-19 Sequential SIR Model Effective Reproduction Number Multivariate Analysis Method T-Method Regression Analysis

The role of water in Earth's mantle

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National Science Review 2020年第1期7卷 224-232页

作者： eiji Ohtani Graduate School of Science Tohoku University

Geophysical observations suggest that the transition zone is wet locally. Continental and oceanic sediment components together with the basaltic and peridotitic components might be transported and accumulated in the transition zone. Low-velocity anomalies at the upper mantle–transition zone boundary might be caused by the existence of dense hydrous magmas. Water can be carried farther into the lower mantle by the slabs. The anomalous Q and shear wave regions locating at the uppermost part of the lower mantle could be caused by the existence of fluid or wet magmas in this region because of the water-solubility contrast between the minerals in the transition zone and those in the lower mantle. δ-H solid solution AlO2H–MgSiO4H2carries water into the lower mantle. Hydrogen-bond symmetrization exists in high-pressure hydrous phases and thus they are stable at the high pressures of the lower mantle. Thus, theδ-H solid solution in subducting slabs carries water farther into the bottom of the lower mantle. Pyrite FeO2Hxis formed due to a reaction between the core and hydrated slabs. This phase could be a candidate for the anomalous regions at the core–mantle boundary.

关键词： water hydrous phase subducting slab transition zone lower mantle hydrogen-bond symmetrization core–mantle boundary

New results on Cll and C12 lattices with applications to Grothendieck categories and torsion theories

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Frontiers of Mathematics in China 2016年第4期11卷 815-828页

作者： toma ALBU Mihai IOSIF Simion Stoilow Institute of Mathematics of the Romanian Academy Research Unit 5 P.O. Box 1-764 RO-010145 Bucharest 1 Romania Bucharest University Department of Mathematics Academiei Str. 14RO-010014 Bucharest 1 Romania

In this paper, which is a continuation of our previous paper [T. Albu, M. Iosif, A. Tercan, The conditions （Ci） in modular lattices, and applications, J. Algebra Appl. 15 （2016）, http： ***/10.1142/S0219498816500018], we investigate the latticial counterparts of some results about modules satisfying the conditions （Cll） or （C12）. Applications are given to Grothendieck categories and module categories equipped with hereditary torsion theories.

关键词： Modular complement lattice C12 theory element lattice upper closed element lattice Goldie dimension continuous lattice essential element uniform lattice condition (Ci) Cll socle Grothendieck category torsion

A Variational Finite Element Model for Large-Eddy Simulations of Turbulent Flows

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Chinese Annals of Mathematics,Series B 2013年第5期34卷 667-682页

作者： toma's Chac'on REBOLLO Roger LEWANDOWSKI Dpto. EDAN & IMUS Universidad de SevillaC/Tarfias/n. 41012 SevillaSpain BCAM-Basque Center for Applied Mathematics AvdaMazarredo14. 48009 BilbaoSpain. Mathematical Research Institute of Rennes UMR CNRS 6625University of Rennes 1 & Fluminance teamINRIABat 22Campus Beaulieu35042 Rennes cedexFrance.

The authors introduce a new Large Eddy Simulation model in a channel, based on the projection on finite element spaces as filtering operation in its variationM form, for a given triangulation （Th）h〉0. The eddy viscosity is expressed in terms of the friction velocity in the boundary layer due to the wall, and is of a standard sub grid-model form outside the boundary layer. The mixing length scale is locally equal to the grid size. The computational domain is the channel without the linear sub-layer of the boundary layer. The no-slip boundary condition （or BC for short） is replaced by a Navier （BC） at the computational wall. Considering the steady state case, the authors show that the variational finite element model they have introduced, has a solution （Vh,Ph）h〉O that converges to a solution of the steady state Navier-Stokes equation with Navier BC.

关键词： Navier-Stokes equations Turbulence modeling Finite elements

Nitrous oxide fluxes from upland soils in central Hokkaido,Japan

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Journal of Environmental Sciences 2008年第11期20卷 1312-1322页

作者： Sonoko D.KIMURA Yo toma Ryusuke HATANO Graduate School of Agriculture Tokyo University of Agriculture and TechnologyTokyo 183-8509Japan Graduate School of Agriculture Hokkaido UniversitySapporo 060-8589Japan

Nitrous oxide (N2O) fluxes from soils were measured using the closed chamber method during the snow-free seasons (middle April to early November),for three years,in a total of 11 upland crop fields in central Hokkaido,*** annual mean N2O fluxes ranged from 2.95 to 164.17 μgN/(m2·h),with the lowest observed in a grassland and the highest in an onion *** instantaneous N2O fluxes showed a large temporal variation with peak emissions generally occurring following fertilization and heavy rainfall eve...

关键词： mineral N pool N2O flux soil upland cropping system

Postoperative functional evaluation of gastrectomy for gastric cancer

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Chinese Journal of Cancer Research 2022年第6期34卷 567-574页

作者： eiji Nomura Department of Gastroenterological and General Surgery Tokai University Hachioji HospitalTokyo 192-0032Japan

To improve the quality of surgical procedures for gastric cancer,it is essential to consider many components comprehensively,including gastric motility,small intestinal absorption,hormones that affect gastric motility and appetite,presence or absence of vagus nerve preservation,esophageal regurgitation on endoscopic findings,in addition to whether or not there is a physiological route for food passage through the ***,proper functional evaluation cannot be performed without considering the form and amount of energy in the nutritional supplement to be loaded,and the posture at the time of *** results of functional evaluation vary according to the method selected from many available options,but we believe that use of the most physiologically accurate,appropriate and selectable option will enable us to arrive at the best resection/reconstruction *** have reported that it is important to consider the preservation of three elements when performing gastrectomy:1)reduction of the extent of gastrectomy,2)preservation of the pylorus,and 3)preservation of the vagus nerve;among which preservation of the remnant stomach is the most ***,the selection of a reconstruction method that maintains secretion of hormones beneficial to gastric motility preserves the energy balance inherent in the human body,and also provides better quality of life.

关键词： Gastric cancer gastrectomy functional evaluation

Implications of excess ^(210)Pb and ^(137)Cs in sediment cores from Mikawa Bay, Japan

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Journal of Environmental Sciences 2009年第5期21卷 707-712页

作者： LU Xueqiang MATSUMOTO eiji Tianjin Academy of Environmental Sciences Tianjin 300191 China Graduate School of Environmental Studies Nagoya University Nagoya 464-8601 Japan

Four sediment cores were collected from Mikawa Bay, Japan, and excess ^210pb and ^137Cs were measured by gamma spectrometry. Sedimentation rates for the four cores were determined by ^210Pb method. The sedimentation rate range is 0.10-0.70 g/（cm^***）. The bio-mixing depth for each core is less than 7.0 cm, and was determined by the excess 210^pb profiles as well. Therefore, the bioturbation is slight. The 210^pb-derived dates coincided with the results from ^137Cs geochronology. Acceleration in sedimentation rate due to environmental alteration has been found in cores A2.5 and 05AS8, representing two depocenters due to their topography. Evidence of the Tokal Flood in 2000 was found in core 05AS8 according to the profiles of both radioisotopes and trace metals.

关键词： ^210pb ^137Cs sedimentation rate Mikawa Bay

Nano-structural Modification of Amorphous Carbon Thin Films by Low-energy Electron Beam Irradiation

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材料热处理学报 2004年第05B期25卷 1247-1252页

作者： eiji Iwamura Masanori Yamaguchi PRESTO Japan Science and Technology Agency Tokyo JapanLamp Company Ushio INC. Himeji Japan

A new approach using a low-energy electron beam radiation system was investigated to synthesize carbon hybrid structures in amorphous carbon thin films. Two types of amorphous carbon films, which were 15at% iron containing film and with column/inter-column structures, were deposited onto Si substrates by a sputtering technique and subsequently exposed to an electron shower of which the energy and dose rate were much smaller compared to an intense electron beam used in a transmission electron microscopy. As a result of the low-energy and low-dose electron irradiation process, graphitic structures formed in amorphous matrix at a relatively low temperature up to 450 K. Hybrid carbon thin films containing onion-like structures in an amorphous carbon matrix were synthesized by dynamic structural modification of iron containing amorphous carbon thin films. It was found that the graphitization progressed more in the electron irradiation than in annealing at 773 K, and it was attributed to thermal and catalytic effects which are strongly related to grain growth of metal clusters. On the other hand, a reversal of TEM image contrast was observed in a-C films with column/inter-column structures. It is presumed that preferable graphitization occurred in the inter-column regions induced by electron irradiation.

关键词：无定形碳溅射石墨化低能电子注辐射毫微结构

Trajectories of endoscopic Barrett esophagus: Chronological changes in a community-based cohort

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World Journal of Gastroenterology 2016年第35期22卷 8060-8066页

作者： Shouji Shimoyama Toshihisa Ogawa Toshiyuki toma Gastrointestinal Unit Settlement Clinic

AIM To elucidate longitudinal changes of an endoscopic Barrett esophagus(BE), especially of short segment endoscopic BE(SSBE). METHODS This study comprised 779 patients who underwent two or more endoscopies between January 2009 and December 2015. The intervals between the first and the last endoscopy were at least 6 mo. The diagnosis of endoscopic BE was based on the criteria proposed by the Japan Esophageal Society and was classified as long segment(LSBE) and SSBE, the latter being further divided into partial and circumferential types. The potential background factors that were deemed to affect BE change included age, gender, antacid therapy use, gastroesophageal reflux disease-suggested symptoms, esophagitis, and hiatus hernia. Time trends of a new appearance and complete regression were investigated by Kaplan-Meier curves. The factors that may affect appearance and complete regression were investigated by χ~2 and Student-t tests, and multivariable Cox regression analysis. RESULTS Incidences of SSBE and LSBE were respectively 21.7% and 0%, with a mean age of 68 years. Complete regression of SSBE was observed in 61.5% of initial SSBE patients, while 12.1% of initially disease free patients experienced an appearance of SSBE. Complete regressions and appearances of BE occurred constantly over time, accounting for 80% and 17% of 5-year cumulative rates. No LSBE development from SSBE was observed. A hiatus hernia was the only significant factor that facilitated BE development(P = 0.03) or hampered(P = 0.007) BE regression. CONCLUSION Both appearances and complete regressions of SSBE occurred over time. A hiatus hernia was the only significant factor affecting the BE story.

关键词： Barrett esophagus Longitudinal vessels Progression Regression Hiatus hernia