Comparison of nitrate export patterns in forested catchments in Japan and the Northeastern United States: A meta‐analysis     

Nobuhito Ohte  Masanori Katsuyama 《水文研究》2019,33(25):3184-3194

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Analysis of formation pressure test results in the Mount Elbert methane hydrate reservoir through numerical simulation     

Masanori Kurihara  Akihiko SatoKunihiro Funatsu  Hisanao OuchiYoshihiro Masuda  Hideo NaritaTimothy S. Collett 《Marine and Petroleum Geology》2011,28(2):502-516

Targeting the methane hydrate (MH) bearing units C and D at the Mount Elbert prospect on the Alaska North Slope, four MDT (Modular Dynamic Formation Tester) tests were conducted in February 2007. The C2 MDT test was selected for history matching simulation in the MH Simulator Code Comparison Study. Through history matching simulation, the physical and chemical properties of the unit C were adjusted, which suggested the most likely reservoir properties of this unit. Based on these properties thus tuned, the numerical models replicating “Mount Elbert C2 zone like reservoir”, “PBU L-Pad like reservoir” and “PBU L-Pad down dip like reservoir” were constructed. The long term production performances of wells in these reservoirs were then forecasted assuming the MH dissociation and production by the methods of depressurization, combination of depressurization and wellbore heating, and hot water huff and puff. The predicted cumulative gas production ranges from 2.16 × 10⁶ m³/well to 8.22 × 10⁸ m³/well depending mainly on the initial temperature of the reservoir and on the production method.This paper describes the details of modeling and history matching simulation. This paper also presents the results of the examinations on the effects of reservoir properties on MH dissociation and production performances under the application of the depressurization and thermal methods.  相似文献   

Orbital motion of a massive object in a dense stellar system     

Masatoshi Taga  & Masanori Iye 《Monthly notices of the Royal Astronomical Society》1998,299(1):111-117

In this paper we show the positional oscillation of a massive object in a dense stellar system by numerical N -body simulations. We found that the central massive object, which at first is placed at rest at the centre of the surrounding spherical stellar system, promptly departs from the centre and rotates in accordance with the rotation of the stellar system, if the stellar system has an appreciable rotation. This oscillatory motion continues for a long time because of the absence of dynamical friction. Such a long-lasting oscillation may explain the asymmetric structure observed in the centres of M31 and NGC 4486B, may cause the secular flow of gaseous elements distributed in the central regions of galaxies on to the massive object, and may ignite activity in the centres of galaxies.  相似文献   

Global shearing modes of galactic disks     

Masanori Iye  Tatsuo Ueda  Masafumi Noguchi  Shinko Aoki 《Astrophysics and Space Science》1983,89(2):363-376

A new scheme has been devised to calculate discrete unstable global shearing spiral modes of gaseous disk models of galaxies. The scheme makes use of the Legendre expansion of eigen functions and the problem of stability analysis is reduced to an eigenvalue problem of an infinite matrix. The spiral patterns of these shearing wave solutions of linearized equations change their form in the course of time due to the differential rotation of the equilibrium disk. These shearing wave solutions are presumed to have intermediate characteristics between so-called density-waves and material arms. Comparison between these shearing modes and the non-shearing normal modes for a series of disk models is presented.  相似文献   

Biogeochemistry of nitrous oxide in groundwater in a forested ecosystem elucidated by nitrous oxide isotopomer measurements   总被引：3，自引：0，他引：3  

K. Koba  K. Osaka  Y. Tobari  S. Toyoda  N. Ohte  M. Katsuyama  N. Suzuki  M. Itoh  H. Yamagishi  M. Kawasaki  S.J. Kim  N. Yoshida  T. Nakajima 《Geochimica et cosmochimica acta》2009,73(11):3115-1037

The biological and physical controls on microbial processes that produce and consume N₂O in soils are highly complex. Isotopomer ratios of N₂O, with abundance of ¹⁴N¹⁵N¹⁶O, ¹⁵N¹⁴N¹⁶O, and ¹⁴N¹⁴N¹⁸O relative to ¹⁴N¹⁴N¹⁶O, are promising for elucidation of N₂O biogeochemistry in an intact ecosystem. Site preference, the nitrogen isotope ratio of the central nitrogen atom minus that of the terminal nitrogen atom, is useful to distinguish between N₂O via hydroxylamine oxidation and N₂O via nitrite reduction.We applied this isotopomer analysis to a groundwater system in a temperate coniferous-forested ecosystem. Results of a previous study at this location showed that the N₂O concentration in groundwater varied greatly according to groundwater chemistry, i.e. NO₃⁻, DOC, and DO, although apportionment of N₂O production to nitrification or denitrification was ambiguous. Our isotopic analysis (δ¹⁵N and δ¹⁸O) of NO₃⁻ and N₂O implies that denitrification is the dominant production process of N₂O, but definitive information is not derived from δ¹⁵N and δ¹⁸O analysis because of large variations in isotopic fractionations during production and consumption of N₂O. However, the N₂O site preference and the difference in δ¹⁵N between NO₃⁻ and N₂O indicate that nitrification contributes to total N₂O production and that most measured N₂O has been subjected to further N₂O reduction to N₂. The implications of N₂O biogeochemistry derived from isotope and isotopomer data differ entirely from those derived from conventional concentration data of DO, NO₃⁻, and N₂O. That difference underscores the need to reconsider our understanding of the N cycle in the oxic-anoxic interface.  相似文献   

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   

Recent developments in seismically isolated buildings in Japan     

Shin Okamoto  Nagahide Kani  Masahiko Higashino  Norihide Koshika  Masayuki Kimizuka  Mitsumasa Midorikawa  Masanori Iiba 《地震工程与工程振动(英文版)》2002,1(2):213-225

The Building Standard Law of Japan and related Enforcement Order and Notifications have been substantially revised since the year 2000 to introduce a performance-based regulatory and deregulation system for building control systems. Up to then, time-history analyses were mandatory for isolated buildings and had to be specially approved by the Minster of the Ministry of Construction (MOC). Simplified design procedures based on the equivalent linear method for seismically isolated buildings have been issued as “Notification 2009 — Structural calculation procedure for buildings with seismic isolation” from MOC, and are now integrated into the Ministry of Land, Infrastructure, and Transportation (MLIT). Along with Notification 2009, “Notification 1446 of year 2000 — Standard for specifications and test methods for seismic isolation devices” was also issued. Buildings with heights equal to or less than 60m and that are designed according to these Notifications, including base isolated buildings, only need approval from local building officials, and no longer require the special approval of the Minister of MLIT. This paper summarizes: 1) some statistics related to buildings with seismic isolation completed up to the end of 2001; 2) simplified design procedures required by Notification 2009 of year 2000; and 3) performance of seismic isolation devices required by Notification 1446 of year 2000.  相似文献   

Neural dynamic modelling on earthquake magnitude series     

Xia-ting Feng  M. Seto  K. Katsuyama 《Geophysical Journal International》1997,128(3):547-556

Earthquake magnitude prediction is of vital importance for human safety. The earthquake is a very complicated and non-linear dynamic process. It cannot be described adequately by any deterministic models. In this paper a neural dynamic modelling for earthquake magnitude prediction is reported. Historical records of earthquake magnitude series are used to construct the optimal non-linear dynamic model, and the consequent outcome of the earthquake behaviour is then predicted by this model. In turn, the latest recorded data set can be fed back to improve the accuracy of the neural dynamic model. The modelling of experiments of three earthquake magnitude series in China and Japan and their extrapolated predictions are included in this paper. The values predicted by extrapolation are in good agreement with the historical data.  相似文献   

Symmetrical fft technique and its applications to earthquake engineering     

Hiroshi Katukura  Susumu Ohno  Masanori Izumi 《地震工程与结构动力学》1989,18(5):717-725

The objective of this paper is to propose an FFT technique symmetrical for time and frequency, in which the symmetrization is done by introducing generating functions. By the symmetrical treatment, it becomes possible to derive several complementary relations in the time and frequency domains. Based on the idea of the symmetrical FFT technique, the phase problem of seismic waves is discussed not only in the frequency domain but also in the time domain. Furthermore, the deconvolution technique to evaluate the minimum-phase-shift and all-pass functions of seismic waves, which is not discussed sufficiently in earthquake engineering, is developed in the two domains. Numerical examples to present these basic ideas are also illustrated in the symmetrical framework.  相似文献   

A three‐component end‐member analysis of streamwater hydrochemistry in a small Japanese forested headwater catchment     

Masanori Katsuyama  Nobuhito Ohte  Sumiji Kobashi 《水文研究》2001,15(2):249-260

Intensive water sampling in conjunction with hydrological observations was conducted during three different rainstorms in order to understand the effects of rainfall events on the temporal variation of streamwater chemistry in a small headwater forest catchment. Concentrations of Na⁺ and SO₄^2? decreased as the discharge rate increased. Hydrograph separation of the components was made using the three‐component model based on the end‐members mixing analysis (EMMA). The three end‐members were:

• 1 the groundwater in the saturated zone that prescribes the chemistry of the baseflow;
• 2 the throughfall that dilutes the streamwater;
• 3 the groundwater in the transient saturated zone prescribed, which was dependent on the groundwater level.

When the groundwater level was lower, only the two components, groundwater in the saturated zone and throughfall, affected the streamwater chemistry. When the groundwater level rose and the saturated zone spread, the groundwater in the transient saturated zone became the third component. When the groundwater in the transient saturated zone contributed to the discharge, this component became the dominant source and the streamwater chemistry was affected by the groundwater chemistry in the transient saturated zone. When this component was discharged as the saturation overland flow, the streamwater chemistry was greatly affected by this component. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献