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Chinese Science Bulletin 2014年第36期59卷 5290-5301页

作者： hiroyuki saitoh Akihiko Machida Katsutoshi Aoki Quantum Beam Science Directorate Japan Atomic Energy Agency Sayo-cho Sayo-gun Hyogo 679-5148 Japan Institute for Materials Research Tohoku University Aoba-kuSendai 980-8577 Japan

The high-pressure technique is a fundamental tool for realizing novel phase transitions, chemical reactions, and other exotic phenomena. Hydrogenation is one example of a high-pressure reaction; at high pressures of several gigapascals, hydrogen becomes chemically active and reacts with metals and alloys to form hydrides. This paper covers a high-pressure study of the hydrogenation process and the synthesis of hydrides using a cubic-type multi-anvil apparatus. The experimental details of a hydrogenation cell assembly, high-temperature and highpressure generation, and an in situ observation technique are presented. These experiments are conducted with the aid of in situ synchrotron radiation X-ray diffraction measurements operated in an energy-dispersive mode in the conventional manner for time-resolved measurements and a newly developed angle-dispersive mode for observation of the crystal growth process during formation of metal hydrides. Two successful cases of high-pressure hydrogenation are presented: aluminum hydride, Al H3, and an aluminum-based alloy hydride, Al2 Cu Hx, which are potential candidates for hydrogen storage materials.

关键词： X射线衍射技术金属氢化物原位测量氢气压力同步加速器同步辐射X射线衍射高压技术晶体生长过程

Improving the performance of conventional base isolation systems by an external variable negative stiffness device under near-fault and long-period ground motions

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Earthquake Engineering and Engineering Vibration 2020年第4期19卷 985-1003页

作者： Sandhya Nepal Masato saitoh Graduate School of Science and Engineering Saitama University255 Shimo-OkuboSakura-kuSaitamaJapan

Recent studies have shown that base-isolated objects with long fundamental natural periods are highly influenced by long-period earthquakes. These long-period waves result in large displacements for isolators, possibly leading to exceedance of the allowable displacement limits. Conventional isolation systems, in general, fail to resist such large displacements. This has prompted the need to modify conventional base isolation systems. The current work focuses on the development of an external device, comprising a unit of negative and positive springs, for improving the performance of conventional base isolation systems. This unit accelerates the change in the stiffness of the isolation system where the stiffness of the positive spring varies linearly in terms of the displacement response of the isolated objects. The target objects of the present study are small structures such as computer servers, sensitive instruments and machinery. Numerical studies show that the increase in the damping of the system and the slope of the linear function is effective in reducing the displacement response. An optimal range of damping values and slope, satisfying the stability condition and the allowable limits of both displacement and acceleration responses when the system is subjected to near-fault and long-period ground motions simultaneously, is proposed.

关键词： base isolation near-fault earthquakes long-period earthquakes negative stiffness variable stiffness

Model tests and numerical analyses on horizontal impedance functions of inclined single piles embedded in cohesionless soil

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Earthquake Engineering and Engineering Vibration 2013年第1期12卷 143-154页

作者： Chandra Shekhar Goit Masato saitoh Department of Civil and Environmental Engineering Saitama University

Horizontal impedance functions of inclined single piles are measured experimentally for model soil-pile systems with both the effects of local soil nonlinearity and resonant *** practical pile inclinations of 5掳 and 10掳 in addition to a vertical pile embedded in cohesionless soil and subjected to lateral harmonic pile head loadings for a wide range of frequencies are *** obtained with low-to-high amplitude of lateral loadings on model soil-pile systems encased in a laminar shear box show that the local nonlinearities have a profound impact on the horizontal impedance functions of *** impedance functions of inclined piles are found to be smaller than the vertical pile and the values decrease as the angle of pile inclination *** values of horizontal impedance functions are obtained for the ＇positive＇ and ＇negative＇ cycles of harmonic loadings,leading to asymmetric force-displacement relationships for the inclined *** of these experimental results is carried out through three-dimensional nonlinear finite element analyses,and the results from the numerical models are in good agreement with the experimental *** analyses conducted on the numerical models suggest that the consideration of local nonlinearity at the vicinity of the soil-pile interface influence the response of the soil-pile systems.

关键词： inclined single piles harmonic loads horizontal impedance functions local nonlinearity finite element model

Mass balance of saline lakes considering inflow loads of rivers and groundwater: the case of Lake Issyk-Kul, Central Asia

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Journal of Arid Land 2021年第12期13卷 1260-1273页

作者： Kei saitoh Rysbek SATYLKANOV Kenji OKUBO Beppu Geothermal Research Laboratory Institute for Geothermal SciencesGraduate School of ScienceKyoto UniversityOita 8740903Japan Tien Shan High Mountain Research Center Institute of Water Problem and Hydropower of National Academy of Sciences of Kyrgyz RepublicBishkek 720033Kyrgyzstan Graduate School of Environmental and Life Science Okayama UniversityOkayama 7008530Japan

This study aimed to elucidate the influence of inflow water on the salinity concentration process of a saline lake and the mass balance of Lake Issyk-Kul,a tectonic saltwater lake in *** on the survey results and meteorological data from 2012 to 2015,we analyzed the dissolved chemical composition loads due to water ***,we discussed the relationship between the increase in salinity and water inflow into the *** the water quality analysis data,we used the tank model to estimate the river inflow and analyze the loads by the L-Q *** groundwater loads were then estimated from the average annual increase in salinity of the lake over a period of 30 *** results suggest that Lake Issyk-Kul was temporarily freshened between about AD 1500 and 1800 when an outflowing river existed,and thereafter,it became a closed lake in AD 1800 and continued to remain a saline lake until *** chemical components that cause salinization are supplied from the rivers and groundwater in the catchment area,and when they flow into the lake,Ca^(2+),HCO_(3)−and Mg^(2+)precipitate as CaCO_(3) and MgCO_(3).These compounds were confirmed to have been left on the lakeshore as *** model analysis showed that 1.67 mg/L of Ca^(2+)and Mg^(2+)supplied from rivers and groundwater are precipitated as evaporite and in other forms per *** the other hand,salinity continues to remain in the lake water at a rate of 27.5 mg/L per *** are the main causes of increased salinity in Lake *** Na^(+)and Cl^(-)are considered to be derived from geothermal water,they will continue to flow in regardless of the effects of human ***,as long as these components are accumulated in Lake Issyk-Kul as a closed lake,the salinity will continue to increase in the future.

关键词： groundwater geothermal water mass balance salinity saline lake L-Q curve

Spectral vegetation indices as the indicator of canopy photosynthetic productivity in a deciduous broadleaf forest

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Journal of Plant Ecology 2013年第5期6卷 393-407页

作者： hiroyuki Muraoka Hibiki M.Noda Shin Nagai Takeshi Motohka Taku M.saitoh Kenlo N.Nasahara Nobuko Saigusa Institute for Basin Ecosystem Studies Gifu University1-1 YanagidoGifu501-1193 Japan Faculty of Life and Environment Sciences University of TsukubaTsukuba305-8572 Japan Research Institute for Global Change Japan Agency for Marine-Earth Science and Technology(JAMSTEC)Yokohama236-0001 Japan Earth Observation Research Center Japan Aerospace Exploration AgencyTsukuba305-8505 Japan Center for Global Environmental Research National Institute for Environmental StudiesTsukuba205-8506 Japan

Aims Understanding of the ecophysiological dynamics of forest canopy photosynthesis and its spatial and temporal scaling is crucial for revealing ecological response to climate *** observations and analyses of plant ecophysiology and optical remote sensing would enable us to achieve these *** order to examine the utility of spectral vegetation indices(VIs)for assessing ecosystem-level photosynthesis,we investigated the relationships between canopy-scale photosynthetic productivity and canopy spectral reflectance over seasons for 5 years in a cool,temperate deciduous broadleaf forest at‘Takayama’super site in central *** Daily photosynthetic capacity was assessed by in situ canopy leaf area index(LAI),(LAI×Vcmax[single-leaf photosynthetic capacity]),and the daily maximum rate of gross primary production(GPPmax)was estimated by an ecosystem carbon cycle *** examined five VIs:normalized difference vegetation index(NDVI),enhanced vegetation index(EVI),green–red vegetation index(GRVI),chlorophyll index(CI)and canopy chlorophyll index(CCI),which were obtained by the in situ measurements of canopy spectral *** Findings Our in situ observation of leaf and canopy characteristics,which were analyzed by an ecosystem carbon cycling model,revealed that their phenological changes are responsible for seasonal and interannual variations in canopy *** correlations were found between the five VIs and canopy photosynthetic capacity over the seasons and years;four of the VIs showed hysteresis-type relationships and only CCI showed rather linear *** the VIs examined,we applied EVI–GPPmax relationship to EVI data obtained by Moderate Resolution Imaging Spectroradiometer to estimate the temporal and spatial variation in GPPmax over central *** findings would improve the accuracy of satellite-based estimate of forest photosynthetic productivity in fine spatial and temporal resolutions,which are

关键词： canopy photosynthesis deciduous broadleaf forest phenology remote sensing vegetation index

Vertical impedance functions of pile groups under low-to-high loading amplitudes:numerical simulations and experimental validation

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 647-666页

作者： Usama Zafar Chandra Shekhar Goit Masato saitoh Riku Fukuda School of Science and Engineering Saitama University255 Shimo-OkuboSaitamaJapan

Piles in a group experience additional displacements in soil due to pile-to-pile interactions apart from those resulting from the external *** effect of these interactions determined assuming soil as an elastic and/or viscoelastic material on pile head impedance functions of the pile group is studied by relating the group stiffness to the static stiffness of a single ***,the prevailing elastic solutions may misestimate the resulting pile group response due to the lack of consideration for either soil(material)and/or soil-pile interface *** is well established that soil behaves nonlinearly under moderate-to-high loading amplitudes,and besides,the soil-pile interface nonlinearity can exist even at small loading *** study addresses the effects of these nonlinearities on the vertical impedance functions of a 3×3-pile group using numerical methods by direct analyses and superposition using pile-to-pile interaction *** numerical results are validated using scaled model tests under 1 g *** results highlight the overestimation of pile-to-pile interactions in the pile group when assuming elastic soil *** cases either by direct analyses or superposition approach involving soil and soil-pile interface nonlinearities agree well with the experimental pile group responses under close-to-elastic and nonlinear conditions.

关键词： impedance functions numerical simulations model-scale experiment superposition approach soil-pile interface nonlinearity

Influence of Gaps Between Multiple Floating Bodies on Wave Forces

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China Ocean Engineering 2000年第4期15卷 407-422页

作者：缪国平 H. Ishida T. saitoh Professor Department of Civil Engineering Kanazawa University Associate Professor Department of Civil Engineering Kanazawa University

The present study aims to give general hints about hydrodynamic interactions for water wave diffraction on a super large floating structure composed of a large number of box-shaped modules with many small gaps in between. And meanwhile, it also aims to seek for an effective way to take the gap influence into consideration without numerical difficulties existing in conventional methods. An asymptotic matching technique is exploited by virtue of the smallness of gaps. Formal potential solutions are established for the near field around the gap ends and the far field away from gap ends, respectively, and the unknowns in those solutions are uniquely determined by asymptotic matching. The eigen-function expansion method is used for the outer far field and a series of pulsating sources at each gap end is introduced to simulate the gap influence. Strong hydrodynamic interaction is observed and a new resonant phenomenon, the mechanism of which differs absolutely from any known ones, is revealed in the present study. Sharp peak responses for both vertical and horizontal wave-exciting forces on each block are found around some special resonance frequencies, which depend on the draft of the structure and the gap width. The present results are of practical significance to the design of links (connectors) of modules for super large floating structures. And the importance is also closely related to the hydro-elasticity analysis for super large floating structures, in which local loads may be as important as the integrated loads.

关键词： super large floating structure wave interaction resonance gap influence

Associations of body mass index and hospital-acquired disability with post-discharge mortality in older patients with acute heart failure

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Journal of Geriatric Cardiology 2022年第3期19卷 209-217页

作者： Akihiro Sakuyama Masakazu saitoh Kentaro Hori Yuichi Adachi Keigo Iwai Masatoshi Nagayama Department of Physical Therapy Faculty of Health ScienceJuntendo UniversityTokyoJapan Department of Rehabilitation Sakakibara Heart InstituteTokyoJapan Department of Cardiology Sakakibara Heart InstituteTokyoJapan

OBJECTIVES To investigate the effect of hospital-acquired disability(HAD)on all-cause mortality after discharge according to the body mass index(BMI)in older patients with acute decompensated heart *** We included 408 patients aged≥65 years who were hospitalized for acute decompensated heart failure and had undergone an acute phase of cardiac rehabilitation at the Sakakibara Heart Institute between April 2013 and September 2015(me-dian age:82 years,interquartile range(IQR):76-86;52%male).Patients were divided into three groups based on BMI at hospital admission:underweight(<18.5 kg/m^(2)),normal weight(18.5 to 25 kg/m^(2)),and overweight(≥25 kg/m^(2)).HAD was defined as a decrease of at least five points at discharge compared to before hospitalization according to the Barthel *** The median follow-up period was 475(IQR:292-730)days,and all-cause mortality during the follow-up period was 84 deaths(21%).According to multivariate Cox regression analysis,being underweight(HR:1.941,95%CI:1.134−3.321,P=0.016)or overweight(HR:0.371,95%CI:0.171−0.803,P=0.012),with normal BMI as the reference,and HAD(HR:1.857,95%CI:1.062−3.250,P=0.030)were independently associated with all-cause *** with HAD exhibited a significantly lower cumulative survival rate in the underweight group(P=0.001)and tended to have a lower cumulative survival rate in the normal weight group(P=0.072).HAD was not significantly associated with cumulative survival in the overweight group(P=0.392).CONCLUSIONS BMI and HAD independently predicted all-cause mortality after discharge in older patients with acute de-compensated heart ***,HAD was significantly associated with higher all-cause mortality after discharge,espe-cially in the underweight group.

关键词： patients acute index

Geometric-phase-induced arbitrary polarization and orbital angular momentum generation in helically twisted birefringent photonic crystal fiber

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Photonics Research 2020年第8期8卷 1278-1288页

作者： TAKESHI FUJISAWA KUNIMASA saitoh Graduate School of Information Science and Technology Hokkaido UniversityJapan

The evolutions of polarization and orbital angular momentum(OAM)states of light in helically twisted birefringent photonic crystal fibers(TB-PCFs)are *** is shown that a circular polarization(CP)component(S3 of a Stokes parameter)is periodically excited when usual linearly polarized(LP)modes of PCF are *** excitation originates from a geometric phase in *** S3 excitation is larger for larger linear birefringence for a fixed twisting *** the linear birefringence is large enough,a CP filtering behavior can be seen in addition to the S3 *** the analytical consideration of the sign of the geometric phase,the TB-PCF with periodical inversion of twisting is proposed to generate arbitrary polarization state on the Poincaré***,an OAM state generation in multimode TB-PCFs is shown for higher-order LP mode *** observing a far-field interference pattern from TB-PCF mixed with LP01 mode,a vortex associated with the OAM state can be *** to the single-mode case,by using periodical twisting inversion,efficient OAM generation is *** results indicate that by simply launching fiber’s LP mode into TB-PCF,arbitrary polarization and OAM states can be generated,leading to a novel mechanism for the manipulation of the spatial state of light.

关键词： polarization fiber momentum

ANALYTICAL SOLUTIONS FOR THE SLOSHING LOADING ON CIRCULAR CYLINDRICAL LIQUID TANKS WITH INTERIOR SEMI-POROUS BARRIERS

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Journal of Hydrodynamics 2001年第2期13卷 32-39页

作者： Miao, G.P. Ishida, H. saitoh, T. Kurosaki, K. Sch. of Naval Arch. and Ocean Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

The estimation of sloshing loading on liquid tanks is of fundamental importance due to the wide and important applications of liquid tanks in various engineering aspects. Analytical solutions for the sloshing loading on circular cylindrical liquid tanks with an interior concentric vertical thin semi-porous barrier under external excitations are presented. And the extensions of the solutions to the elastic vibrations and to the high frequency limit to count for the earthquake response are also included. A clear view on the influence of semi-porous barriers to the sloshing response of oscillating tanks is obtained by the analyses of systematic computational results. The present results may offer guidance to the corresponding design for liquid tanks of various applications and also a basis of comparison for the development of more sophisticated numerical methods for hydrodynamic and hydro-elastic analyses.

关键词： Boundary conditions Mathematical models Tanks (containers) Vibration measurement