Trace Element Analysis of NIST SRM 614 and 616 Glass Reference Materials by Laser Ablation Microprobe-Inductively Coupled Plasma-Mass Spectrometry   总被引：3，自引：0，他引：3  

Masanori Kurosawa  Simon E. Jackson  Shigeho Sueno 《Geostandards and Geoanalytical Research》2002,26(1):75-84

Fifty elements in NIST SRM 614 and 616 glass reference materials were determined by laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS). The values determined for NIST SRM 614 agreed well with the NIST-certified and information values (mean relative difference ± 3.6%), except for B, Sc and Sb. The values determined for NIST SRM 616 agreed with the NIST-certified and information values within a mean relative difference of ± 1.5%, except for B, Sc and Ga. In addition, at an 80 μm sampling scale, NIST SRM 614 and 616 glass discs were homogeneous for trace elements within the observed precisions of 5 and 15% (mean), respectively. Detection limits were in the range 0.01 - 0.3 μg g⁻¹ for elements of lower mass numbers (amu < 80) and 1 - 10 ng g⁻¹ for heavy elements (amu > 80). Detection at the sub ng g⁻¹ level is possible for most of the heavy elements by using an ablation pit size larger than 10 0 μm.  相似文献   

Patterns in the hydrogen and trace element compositions of mantle olivines   总被引：1，自引：0，他引：1  

M. Kurosawa  H. Yurimoto  S. Sueno 《Physics and Chemistry of Minerals》1997,24(6):385-395

 The concentrations of hydrogen and the other trace elements in olivines from mantle xenoliths have been determined by secondary ion mass spectrometry (SIMS) for clarifying the incorporation mechanism and the behavior of the hydrogen. The hydrogen contents in olivines from mantle xenoliths range from 10 to 60 ppm wt. H₂O and the concentration range is consistent with the previous infrared (IR) spectroscopic data. IR spectra of the olivine crystals show no effects of the weathering or secondary alteration. The hydrogen is distributed homogeneously among olivine grains in each mantle xenolith. However, the hydrogen contents of the olivine crystals are less than those for the olivine phenocrysts crystallized from the host magma. Olivine inclusions in diamonds also show similar hydrogen contents to the xenolithic olivines. Thus the hydrogen content of xenolithic olivines does not attain equilibrium with water in the host magma during the transportation from the Earth's mantle to the surface, and is taken as a reflection of the hydrogen condition in the mantle. Correlations of hydrogen with trivalent cation contents in garnet peridotitic olivines indicate the incorporation of hydrogen into mantle olivines by a coupled substitution mechanism, with the hydrogen present in the form of hydroxyl in oxygen positions adjacent to the M site vacancies. The hydrogen content of xenolithic olivines increases with pressure but decreases with increasing temperature, suggesting importance of olivine as a water reservoir at low temperature regions such as in subducting slabs. Received August 15, 1995/Revised, accepted November 19, 1996  相似文献   

Contribution of sea-surface wind curl to the maintenance of the SST gradient along the upstream Kuroshio Extension in early summer     

Naoki Sato  Masami Nonaka  Yoshikazu Sasai  Hideharu Sasaki  Youichi Tanimoto  Ryuichi Shirooka 《Journal of Oceanography》2016,72(5):697-705

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Determination of the origins and recharge rates of the Sfax aquifer system (southeastern Tunisia) using isotope tracers     

Rahma Ayadi  Kamel Zouari  Hakim Saibi  Rim Trabelsi  Hafedh Khanfir  Ryuichi Itoi 《Environmental Earth Sciences》2016,75(8):636

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Subduction-related mafic to felsic magmatism in the Malayer–Boroujerd plutonic complex,western Iran     

Reza Deevsalar  Ryuichi Shinjo  Jean P. Liégeois  Mohammad V. Valizadeh  Jamshid Ahmadian  Hadi Yeganehfar  Mamoru Murata  Iain Neill 《Swiss Journal of Geoscience》2018,111(1-2):269-293

The Malayer–Boroujerd plutonic complex (MBPC) in western Iran, consists of a portion of a magmatic arc built by the northeast verging subduction of the Neo-Tethys plate beneath the Central Iranian Microcontinent (CIMC). Middle Jurassic-aged felsic magmatic activity in MBPC is manifested by I-type and S-type granites. The mafic rocks include gabbroic intrusions and dykes and intermediate rocks are dioritic dykes and minor intrusions, as well as mafic microgranular enclaves (MMEs). MBPC Jurassic-aged rocks exhibit arc-like geochemical signatures, as they are LILE- and LREE-enriched and HFSE- and HREE-depleted and display negative Nb–Ta anomalies. The gabbro dykes and intrusions originated from metasomatically enriched garnet-spinel lherzolite [Degree of melting (f_mel) ~ 15%] and exhibit negative Nd and positive to slightly negative ε_Hf(T) (+ 3.0 to ? 1.6). The data reveal that evolution of Middle Jurassic magmatism occurred in two stages: (1) deep mantle-crust interplay zone and (2) the shallow level upper crustal magma chamber. The geochemical and isotopic data, as well as trace element modeling, indicate the parent magma for the MBPC S-type granites are products of upper crustal greywacke (f_mel: 0.2), while I-type granites formed by partial melting of amphibolitic lower crust (f_mel: 0.25) and mixing with upper crustal greywacke melt in a shallow level magma chamber [Degree of mixing (f_mix): 0.3]. Mixing between andesitic melt leaving behind a refractory dense cumulates during partial crystallization of mantle-derived magma and lower crustal partial melt most likely produced MMEs (f_mix: 0.2). However, enriched and moderately variable ε_Nd(T) (? 3.21 to ? 4.33) and high (⁸⁷Sr/⁸⁶Sr)_i (0.7085–0.7092) in dioritic intrusions indicate that these magmas are likely experienced assimilation of upper crustal materials. The interpretations of magmatic activity in the MBPC is consistent with the role considered for mantle-derived magma as heat and mass supplier for initiation and evolution of magmatism in continental arc setting, elsewhere.  相似文献   

Wave energy in surface layers for energy-based damage evaluation     

Takaji Kokusho  Ryuichi Motoyama  Hiroshi Motoyama 《Soil Dynamics and Earthquake Engineering》2007,27(4):354-366

Seismic wave energy in surface layers is calculated based on vertical array records at four sites during the 1995 Hyogo-ken Nambu earthquake by assuming vertical propagation of SH waves. The upward energy generally tends to decrease as it goes up from the base layer to the ground surface particularly in soft soil sites. Theoretical study on 1D multi-layers model to investigate the basic energy flow mechanism indicates that the energy at the ground surface can be smaller on softer soils due to high soil damping during strong shaking even if resonance effect is considered. A simple calculation for a shear-vibrating structure resting on foundation ground shows that induced strain in the structure is directly related to the energy or the energy flux of surface layers. Hence, a general perception that soft soil sites tend to suffer heavier damage than stiff sites should be explained not by greater incident energy but by other reasons such as degree of resonance. Furthermore, it is recommended that not only acceleration or velocity but also S-wave velocity should be specified at a layer where a design seismic motion is given, so that the seismic wave energy can clearly be quantified in seismic design practice.  相似文献   

GIS-based landslide susceptibility zonation for roadside slope repair and maintenance in the Himalayan region     

Bhoj Raj Pantha Ryuichi Yatabe Netra Prakash Bhandary 《《幕》》2008,31(4):384-391

Roadside slope failure is a common problem in the Himalayan region as road construction activities disturb natural slopes. Therefore, landslide susceptibility zonation is necessary for roadside slope disaster management and planning development activities. In this study, we consider a 53-kin section of a major highway in Nepal where road services are suspended for several days in the monsoon season every year. A number of methods have been used for landslide susceptibility zonation. We employed a bivariate statistical approach for this study. Relevant thematic layer maps represent- ing various factors （e.g., slope, aspect, land use, lithology, drainage density, proximity to stream and proximity to road） that are related to landslide activity, have been prepared using Geographic Information System （GIS） techniques. A total of 277 landslides （covering a total of 29.90 km2） of various dimensions have been identified in the area. A landslide susceptibility map was prepared by overlaying a landslide inventory map with various parameter maps segmented into various relevant classes. The landslide susceptibility index was seg- mented into five zones, viz. very low, low, moderate, high and very high susceptibility. Landslide susceptibility zonation maps are useful tools for the efficient planning and management of roadside slope repair and maintenance tasks in the Himalayan region.  相似文献   

Spectral element analysis to evaluate the stability of long and steep slopes   总被引：1，自引：1，他引：0  

Ram Chandra Tiwari  Netra Prakash Bhandary  Ryuichi Yatabe 《Acta Geotechnica》2014,9(5):753-770

This paper evaluates the stability of long and steep slopes examining the effect of the critical length/depth ratio, L/H, and critical slope angle, β _cr, by comparing the results of infinite slope equation with the spectral element method. In addition, the influence of uphill and downhill boundaries on stability of long and steep slopes is also evaluated in theoretical domains. As an example, this paper presents a stability analysis of long and steep vegetated and barren slopes in saturated and seismic conditions, and also evaluates the effectiveness of the infinite slope equation for those slopes. In the vegetated slopes, the root zone may not extend to the whole depth of slope, which may lead to overestimating the factor of safety by infinite slope equation. This paper examines the applicability of the infinite slope equation for infinitely long, steep, and shallow slope model by comparing the results of the spectral element method.  相似文献   

3D SEM Approach to Evaluate the Stability of Large-Scale Landslides in Nepal Himalaya   总被引：3，自引：0，他引：3  

Ram Chandra Tiwari  Netra Prakash Bhandary  Ryuichi Yatabe 《Geotechnical and Geological Engineering》2015,33(4):773-793

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Radial and rotational velocities of young brown dwarfs and very low-mass stars in the Upper Scorpius OB association and the ρ Ophiuchi cloud core     

Ryuichi Kurosawa  Tim J. Harries  S. P. Littlefair 《Monthly notices of the Royal Astronomical Society》2006,372(4):1879-1887

We present the results of a radial velocity (RV) survey of 14 brown dwarfs (BDs) and very low-mass (VLM) stars in the Upper Scorpius OB association (UScoOB) and three BD candidates in the ρ Ophiuchi dark cloud core. We obtained high-resolution echelle spectra at the Very Large Telescope using the Ultraviolet and Visual Echelle Spectrograph (UVES) at two different epochs for each object, and measured the shifts in their RVs to identify candidates for binary/multiple systems in the sample. The average time separation of the RV measurements is 21.6 d, and our survey is sensitive to the binaries with separation <0.1 au. We found that four out of 17 objects (or 24⁺¹⁶₋₁₃ per cent by fraction) show a significant RV change in 4–33 d time-scale, and are considered as binary/multiple 'candidates'. We found no double-lined spectroscopic binaries in our sample, based on the shape of cross-correlation curves. The RV dispersion of the objects in UScoOB is found to be very similar to that of the BD and VLM stars in Chamaeleon I (Cha I). We also found the distribution of the mean rotational velocities ( v   sin   i ) of the UScoOB objects is similar to that of the Cha I, but the dispersion of v   sin   i is much larger than that of the Cha I objects.  相似文献