Further characterization of carbonaceous materials in Hayabusa‐returned samples to understand their origin     

Masayuki Uesugi  Motoo Ito  Hikaru Yabuta  Hiroshi Naraoka  Fumio Kitajima  Yoshinori Takano  Hajime Mita  Yoko Kebukawa  Aiko Nakato  Yuzuru Karouji 《Meteoritics & planetary science》2019,54(3):638-666

Carbonaceous materials in the sample catcher of the Hayabusa spacecraft were assigned as category 3 particles. We investigated the category 3 particles with a suite of in situ microanalytical methods. Possible contaminants collected from the cleanrooms of the spacecraft assembly and extraterrestrial sample curation center (ESCuC) were also analyzed in the same manner as category 3 particles for comparison. Our data were integrated with those of the preliminary examination team for category 3 particles. Possible origins for the category 3 particles include contamination before and after the operation of the Hayabusa spacecraft.  相似文献   

Evaluation and forecast of human impacts based on land use changes using multi-temporal satellite imagery and GIS: A case study on Zanjan,Iran     

Mohsen Ahadnejad  Yoshihisa Maruyama  Fumio Yamazaki 《Journal of the Indian Society of Remote Sensing》2009,37(4):659-669

Land use and land cover changes due to human activities in a time sequence. Detection of such changes may help decision makers and planners to understand the factors in land use and land cover change in order to take effective and useful measures. Remote sensing and GIS techniques may be used as efficient tools to detect and assess land use change.  相似文献   

Enrichment of alkanes within a phytoplankton bloom during an in situ iron enrichment experiment in the western subarctic Pacific     

Sohiko Kameyama  Urumu Tsunogai  Fumiko Nakagawa  Motoki Sasakawa  Daisuke D. Komatsu  Akira Ijiri  Junko Yamaguchi  Takeo Horiguchi  Hiroshi Kawamura  Aika Yamaguchi  Atsushi Tsuda 《Marine Chemistry》2009,115(1-2):92-101

During the Subarctic Pacific Iron Experiment for Ecosystem Dynamics Study ΙΙ (SEEDS-II), we monitored variations in the concentrations of non-methane hydrocarbons (NMHCs), CH₃Cl, N₂O, and CH₄ within a phytoplankton bloom. Stable isotopic compositions were also determined to evaluate the sources of the variations. Although there was little variation in either the concentrations or the stable isotopic compositions of alkenes, CH₃Cl, N₂O, and CH₄ during the 23-day observation period, alkane concentrations increased substantially as the phytoplankton bloomed. The column-integrated quantities of alkanes increased to 3 times pre-bloom levels for C₂H₆, 5 times for C₃H₈, and 20 times for n-C₄H₁₀. The δ¹³C values of both C₂H₆ and C₃H₈ remained almost constant while concentrations increased, whereas that of n-C₄H₁₀ increased by about 12‰. To evaluate the sources of the alkanes produced during the bloom, we compared their δ¹³C values with those of alkanes produced in axenic phytoplankton cultures in our laboratory. We concluded that during the SEEDS-ΙΙ experiment the major portions of C₂H₆ and C₃H₈ were produced during the autolysis of diatoms cells, whereas n-C₄H₁₀ was produced during autolysis of other phytoplankton cells such as cryptophytes and dinoflagellates.  相似文献   

Effects of hypoxia on benthic organisms in Tokyo Bay, Japan: a review     

Kodama K  Horiguchi T 《Marine pollution bulletin》2011,63(5-12):215-220

Bottom hypoxia (dissolved oxygen concentration ≤2 ml l(-1)) from anthropogenic eutrophication is a growing global concern. Here, we summarized characteristics of hypoxia and its effects on benthic organisms in Tokyo Bay. Despite recent decreases in nutrient inputs, hypoxia has been increasing in duration and spatial extent, suggesting that the substantial loss of tidal flats from reclamation is contributing to a decrease in the ability of Tokyo Bay to recycle nutrients. Hypoxia develops in the central to northern part of the bay and persists from spring to autumn, causing defaunation of benthic organisms. After the abatement of hypoxia in autumn, the defaunated area is recolonized, either through migration or larval settlement. Some megabenthic species with a spawning peak in spring and summer experience failure of larval settlement, which is probably due to hypoxia. The adverse effects of hypoxia are an impediment to recovery of benthic organisms in Tokyo Bay.  相似文献   

高岭土一维增湿的湿陷-流变分析方法研究     

邓检良  许强  龙冈文夫 《岩土力学》2013,34(10):2857-2862

塑性单元体与黏性单元体并联之后再与弹性单元体串联即构成三要素模型,其各单元体都具有非线性本构关系。通过考虑增湿过程中饱和度对三要素模型中的黏性单元体和塑性单元体的影响,建立了弹-塑-黏性与湿陷性耦合的湿陷流变本构模型。湿陷对塑性单元体的影响表现为应变不变条件下屈服应力的降低;而对黏性单元体的影响表现为速率敏感系数的升高。两种影响可以通过试验确定。以此模型为基础,分析了高岭土的单轴压缩固结试验中的湿陷-流变变形,提出了一种湿陷-流变分析方法。试验中,在干燥条件下观测了蠕变;在增湿过程中观测了湿陷。试验中对含水量的测量精度高。理论所得含水率-应变-时间关系与实测结果接近,并区分了增湿过程中的湿陷和干燥条件下的蠕变,证明了本方法的有效性。  相似文献   

Monitoring and evaluation of the urban reconstruction process in Bam,Iran, after the 2003 <Emphasis Type="Italic">M</Emphasis><Subscript>w</Subscript> 6.6 earthquake     

S. Omid Hashemi-Parast  Fumio Yamazaki  Wen Liu 《Natural Hazards》2017,85(1):197-213

In this study, we tracked and analyzed the reconstruction process in Bam, Iran, after the city was struck by an earthquake with a M _w of 6.6 on December 26, 2003. We adopted three approaches to comprehensively assess the city’s post-earthquake reconstruction and to shed light on the progress and sustainability of disaster recovery projects. We applied the following methodology. First, we obtained official statistics and reports that included quantitative and qualitative evaluations of the reconstruction process to evaluate the overall outcome of the government’s reconstruction projects. Second, we examined photographs taken during field surveys conducted in 2004, 2007, and 2014 to assess changes within the city. Last, we analyzed three satellite images of Bam—the first taken 3 months before the earthquake, the second immediately after the earthquake, and the third 8 years after the earthquake—to assess the progress of reconstruction work and changes in land cover and land use. The results indicated that considerable progress had been made in reconstructing some of the damaged areas. However, progress was relatively slow in severely damaged areas.  相似文献   

The micrometeoroids in the thermosphere and mesosphere     

Fumio Kamijo 《Astrophysics and Space Science》1991,181(1):147-152

This Letter reviews the results by computer simulations on the three-body problem carried out at Leningrad University Astronomical Observatory (Anosova, 1986, 1988, 1989). The intensive systematic studies of triple systems with negative and positive total energies have yielded the general features of the evolution of these systems. The processes of formation of the wide and hard binaries have been studied in details. The scenario of the general class of the final motions of the triple systems with negative total energy is considered, the necessary conditions of disruption of these systems are formulated.  相似文献   

Hardened foliated fault gouge from the Nojima Fault zone at Hirabayashi: Evidence for earthquake lightning accompanying the 1995 Kobe earthquake?   总被引：2，自引：0，他引：2  

Yuji Enomoto  Fumio Asuke  Zhong Zheng  Hiroyuki Ishigaki 《Island Arc》2001,10(3-4):447-456

  相似文献   

A Numerical Simulation of the Seasonal Cycle of Temperature, Salinity and Velocity Fields in Tokyo Bay     

Fumio Horiguchi  Joji Yamamoto  Kisaburo Nakata 《Marine pollution bulletin》2001,43(7-12):145-153

To understand when oxygen-depleted waters occur, how they develop and when they dissipate in inner Tokyo Bay, realistic simulations were attempted with fine spatial and temporal resolution by applying realistic time dependent external forcing. A 3D hydrodynamic model was driven by time-dependent external forcing factors/parameters such as solar radiation, air temperature, relative humidity, wind velocity, and fluvial discharge, under the open boundary conditions of 1995. A simulated time series of salinity and temperature agreed fairly well with observed data, except in summer. The model failed to reproduce the development of the surface mixed layer in summer. Several sensitivity analyses on the external forcing parameters such as wind velocity and vertical diffusivity were conducted to reproduce the mixed layer. However, changing these parameter values did not improve the model results.  相似文献   

Seismic response analysis on the stability of running vehicles     

Yoshihisa Maruyama  Fumio Yamazaki 《地震工程与结构动力学》2002,31(11):1915-1932

The seismometer network of the Japanese expressway system has been enhanced since the 1995 Kobe earthquake. Using earthquake information from the instruments, the expressways are closed if the peak ground acceleration (PGA) is larger than or equal to 80cm/s². The aim of this regulation is to avoid secondary disasters, e.g. cars running into the collapsed sections. However, recent studies on earthquake damage have revealed that expressway structures are not seriously damaged under such‐level of earthquake motion. Hence, we may think of relaxing the regulation of expressway closure. But before doing this, it is necessary to examine the effects of shaking to automobiles since the drivers may encounter difficulties in controlling their vehicles and traffic accidents may occur. In this study, a vehicle was modelled with a six‐degree‐of‐freedom system and its responses were investigated with respect to PGA, peak ground velocity (PGV) and Japan Meteorological Agency (JMA) seismic intensity using five ground motion records. It was observed that the response of the vehicle shows a larger amplitude for the record that has larger response spectrum in the long period range compared to other records. However, similar response amplitudes of the vehicle were observed for all the records with respect to the JMA seismic intensity. The response characteristics of the vehicle model may be very useful for decision‐making regarding the relaxation of the expressway closure under seismic motion. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献