The orbital stability of planets trapped in the first-order mean-motion resonances     

Yuji Matsumoto  Makiko Nagasawa  Shigeru Ida 《Icarus》2012,221(2):624-631

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Semi-brittle behavior of wet olivine aggregates: the role of aqueous fluid in faulting at upper mantle pressures     

Tomohiro?OhuchiEmail author  Xinglin?Lei  Yuji?Higo  Yoshinori?Tange  Takeshi?Sakai  Kiyoshi?Fujino 《Contributions to Mineralogy and Petrology》2018,173(10):88

The role of aqueous fluid in fracturing in subducting slabs was investigated through a series of deformation experiments on dunite that was undersaturated (i.e., fluid-free) or saturated with water (i.e., aqueous-fluid bearing) at pressures of 1.0–1.8 GPa and temperatures of 670–1250 K, corresponding to the conditions of the shallower regions of the double seismic zone in slabs. In situ X-ray diffraction, radiography, and acoustic emissions (AEs) monitoring demonstrated that semi-brittle flow associated with AEs was dominant and the creep/failure strength of dunite was insensitive to the dissolved water content in olivine. In contrast, aqueous fluid drastically decreased the creep/failure strength of dunite (up to ~?1 GPa of weakening) over a wide range of temperatures in the semi-brittle regime. Weakening of the dunite by the aqueous fluid resulted in the reduction of the number of AE events (i.e., suppression of microcracking) and shortening of time to failure. The AE hypocenters were located at the margin of the deforming sample while the interior of the faulted sample was aseismic (i.e., aseismic semi-brittle flow) under water-saturated conditions. A faulting (slip rate of ~?10^?3 to 10^?4 s^?1) associated with a large drop of stress (Δσ?~?0.5 to 1 GPa) and/or pressure (ΔP?~?0.5 GPa) was dominant in fluid-free dunite, while a slow faulting (slip rate?<?8?×?10^?5 s^?1) without any stress/pressure drop was common in water-saturated dunite. Aseismic semi-brittle flow may mimic silent ductile flow under water-saturated conditions in subducting slabs.  相似文献   

Effectiveness of superelastic bars for seismic rehabilitation of clay‐unit masonry walls     

Kshitij C. Shrestha  Yoshikazu Araki  Takuya Nagae  Toshihiro Omori  Yuji Sutou  Ryosuke Kainuma  Kiyohito Ishida 《地震工程与结构动力学》2013,42(5):725-741

This paper presents the results on shaking table tests of half‐scale brick walls performed to investigate the effectiveness of newly developed Cu–Al–Mn superelastic alloy (SEA) bars in retrofitting of historical masonry constructions. Problems associated with conventional steel reinforcing bars lie in degradation of stiffness and strength, or pinching phenomena, under cyclic loading, and presence of large residual cracks in structures during and after intense earthquakes. This paper attempts to resolve the problems by applying newly developed Cu–Al–Mn SEA bars, characterized by large recovery strain, low material cost, and high machinability, as partial replacements for steel bars. Sets of unreinforced, steel reinforced, and SEA‐reinforced specimens are subjected to scaled earthquake excitations in out‐of‐plane direction. Whereas steel‐reinforced specimens showed large residual inclinations, SEA‐reinforced specimens resulted in stable rocking response with slight residual inclinations. Corresponding nonlinear finite element (FE) models are developed to simulate the experimental observations. The FE models are further used to examine the sensitivity of the response with respect to the variations in experimental conditions. Both the experimental and numerical results demonstrate the superiority of Cu–Al–Mn SEA bars to conventional steel reinforcing bars in avoiding pinching phenomena. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Multivariate analysis of trace elements in shallow groundwater in Fuchu in western Tokyo Metropolis,Japan     

Dang Quoc Thuyet  Hirotaka Saito  Takeshi Saito  Shigeoki Moritani  Yuji Kohgo  Toshiko Komatsu 《Environmental Earth Sciences》2016,75(7):559

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Ceramic waste glass fiber-reinforced plastic-containing filtering materials for turbid water treatment     

Kentaro Yasui  Shogo Goto  Hiroyuki Kinoshita  Shuta Kamiunten  Toshifumi Yuji  Yoshimi Okamura  Narong Mungkung  Mitsuhiro Sezaki 《Environmental Earth Sciences》2016,75(15):1135

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Geography with GIS     

Yuji Murayama 《GeoJournal》2000,52(3):165-171

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通痹颗粒治疗类风湿关节炎临床疗效及对氧化应激的影响          下载免费PDF全文

龙林钰  柳玉佳  吴伊莹 《应用海洋学学报》2023,39(2):18

目的：观察通痹颗粒治疗气血亏虚、痰瘀互结型类风湿关节炎（RA）的临床疗效及对氧化应激的影响。方法：将60 例气血亏虚、痰瘀互结型RA患者随机分为治疗组和对照组,每组各30 例。对照组予甲氨蝶呤联合美洛昔康治疗,治疗组在对照组基础上加通痹颗粒治疗,2组疗程均为8周。比较2组综合疗效,中医证候积分,血清学指标［血沉（ESR）、C反应蛋白（CRP）］水平,氧化应激指标［超氧化物歧化酶（SOD）、丙二醛（MDA）］水平及不良反应。结果：总有效率治疗组为83.33%（25/30）,对照组为60.00%（18/30）,组间比较,差异有统计学意义（P<0.05）;治疗后2组中医证候积分与ESR、CRP、MDA水平均较治疗前降低,SOD水平较治疗前升高,且治疗组改善程度优于对照组（P<0.05或P<0.01）。结论：通痹颗粒可改善气血亏虚、痰瘀互结型RA患者的临床症状、体征、实验室指标,并能调节氧化应激状态,且不良反应少,值得临床推广应用。  相似文献   

Ion microprobe uranium‐thorium‐lead dating of Shergotty phosphates     

Yuji Sano  Kentaro Terada  Setsuo Takeno  Lawrence a. Taylor  Harry y. Mcsween 《Meteoritics & planetary science》2000,35(2):341-346

Abstract— We report ion microprobe U‐Th‐Pb dating of Shergotty phosphates by means of the sensitive high‐resolution ion microprobe (SHRIMP) recently installed at Hiroshima University, Japan. ten analyses of whitlockite (merrillite) and three analyses of apatite indicate a ²³⁸u/²⁰⁶pb isochron age of 225 ± 200 ma and a tera‐wasserburg concordia‐constrained linear three‐dimensional isochron age of 217 ± 110 ma in the ²³⁸u/²⁰⁶pb‐²⁰⁷pb/²⁰⁶pb²⁰⁴pb/²⁰⁶pb diagram. These ages agree well with the 232Th‐208pb age of 189 ± 83 Ma, which suggests that primary crystallization or a shock metamorphic event defined the formation age of the phosphate minerals. The average of the later two ages, 204 ± 68 Ma, is consistent with the previously published Rb‐Sr age of 165 ± 11 Ma and U‐Th‐Pb age of ～200 Ma. These show marginal agreement with the ⁴⁰Ar‐³⁹Ar age of 254 ± 10 Ma but are significantly different from the Sm‐Nd age of 360 ± 16 Ma. Taking into account the closure temperature of the U‐Pb system in apatite, we suggest the time that Shergotty last experienced a temperature of ～900 °C was 204 ± 68 Ma.  相似文献   

Implications of meso-scale eddies caused by frontal disturbances of the Kuroshio Current for anchovy recruitment   总被引：3，自引：1，他引：2  

Nakata  Hideaki; Kimura  Shingo; Okazaki  Yuji; Kasai  Akihide 《ICES Journal of Marine Science》2000,57(1):143-152

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Helium isotopes of seawater in the Japan Sea     

Naoto Takahata  Yuji Sano  Keika Horiguchi  Kotaro Shirai  Toshitaka Gamo 《Journal of Oceanography》2008,64(2):293-301

We have collected fifty-five seawater samples at seven stations at various depths in the Yamato and Japan Basins of the Japan Sea and measured their helium isotopic ratios. The ³He/⁴He ratios vary from 0.997 R_atm to 1.085 R_atm where R_atm is the atmospheric ratio. The maximum ³He excesses about 8%, are observed at mid-depth (1000 m), and these values are significantly lower than those observed in deep Pacific waters. This implies that mantle-derived helium in deep Pacific water cannot enter the Japan Sea since it is an almost landlocked marginal sea. The observed 8% excess ³He may be attributable to the decay product of tritium. Slightly higher ³He/⁴He ratios in the Bottom Water were observed in the Yamato Basin than in the Japan Basin. The ventilation ages of seawater shallower than 1000 m are calculated as about 5 to 20 years, which is consistent with the CFC ages reported in the literature. There is a positive correlation between the apparent oxygen utilization and ³H-³He ages. The estimated oxygen utilization rate from the correlation in a layer between 500 m and 1000 m is about 3 μmol/kg/yr, which is similar to that in the eastern subtropical North Atlantic.  相似文献