Polarization measurements using the Bragg crystal spectrometers on Hinotori     

Kyo Akita  Katsuo Tanaka  Tetsuya Watanabe 《Solar physics》1983,86(1-2):101-105

The two Bragg crystal spectrometers on board Hinotori provide a new technique for measuring linear polarization of the soft X-ray line emission from solar flares. The results of the measurements of large (X class) flares are given in this paper, and the polarization degree averaged over the soft X-ray maximum phases is estimated to be less than 4%.  相似文献   

Accurate Isotopic and Concentration Analyses of Small Amounts of Pb Using Isotope Dilution Coupled with the Double Spike Technique   总被引：1，自引：0，他引：1  

Takeshi Kuritani  Tomohiro Usui    Tetsuya Yokoyama  Eizo Nakamura 《Geostandards and Geoanalytical Research》2006,30(3):209-220

A new method has been developed for the simultaneous determination of Pb abundance and Pb isotopic composition with high precision and accuracy for small test portion masses by thermal ionisation mass spectrometry. In this method, a ²⁰⁵pb-²⁰⁴pb double spike is added to samples prior to the chemical separation of Pb, and the isotopic composition of the spike-sample mixture is determined rigorously by the double spike technique using a ²⁰⁷Pb-²⁰⁴Pb spike. The isotopic composition and concentration of Pb in the sample are then obtained by utilising the principle of isotope dilution. Using this technique, replicate determinations of Pb from NIST SRM 981 and GSJ JP-1 (peridotite; 0.07 μg g⁻¹ Pb) were performed. The measured concentration and isotopic data were identical, within uncertainty, to published data or to data that were determined independently in this study. The application of this method to U-Pb dating and the determination of the "initial" Pb isotopic composition was also tested. Lead isotopic compositions and the concentrations of Pb, Th and U were determined for a single batch of samples, through the addition of ²⁰⁵pb-²⁰⁴pb, ²³⁰Th and ²³⁵U spikes to samples prior to chemical separation. Also in these experiments, we confirmed that this routine gives accurate data for Pb, Th and U concentrations and Pb isotopic compositions.  相似文献   

Effect of the development of notches and tension cracks on instability of limestone coastal cliffs in the Ryukyus, Japan   总被引：1，自引：0，他引：1  

Tetsuya Kogure  Hisashi Aoki  Akira Maekado  Takashi Hirose  Yukinori Matsukura 《Geomorphology》2006,80(3-4):236-244

Notches cut by waves are currently developing at the base of vertical coastal limestone cliffs in Okinawa, Japan. The cliff height varies from 3.0–22.1 m, and the maximum notch depth is 8.8 m. Many rectangular or cubic blocks, which appear to have originated from cliff failures, are found on platforms in front of the cliffs. On the flat top surface of the cliff, tension cracks often run parallel to the cliff face. The vertical face of the cliffs displays small undulations but no sliding striation, suggesting that cliff failures have been caused by toppling rather than by shearing or sliding. We use slope stability analysis to determine the critical condition for toppling failure. Physical and mechanical properties of the cliff material were first obtained from laboratory tests. The results indicate that the strength of limestone shows a scale effect, such that the strength decreases with increasing size of the test specimens. Based on this result, we estimated the strength of a rock mass corresponding to the size of the coastal cliff. Cliff stability was then analyzed using a cantilever beam model. Comparison of the stability analysis and the dimension of fallen blocks indicates that toppling failure is strongly associated with the development of notches and tension cracks.  相似文献   

Accelerator analyses of tributyltin chloride associated with a tributyltin resistant marine microorganism     

Kubota N  Mimura H  Yamauchi T  Kitamura A 《Marine pollution bulletin》2004,48(7-8):800-805

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Nonlinear sloshing in a floating‐roofed oil storage tank under long‐period seismic ground motion     

Tetsuya Matsui  Takashi Nagaya 《地震工程与结构动力学》2013,42(7):973-991

A hybrid analytical and FEM is proposed to investigate the nonlinear sloshing in a floating‐roofed oil storage tank under long‐period seismic ground motion. The tank is composed of a rigid cylindrical wall and a flat bottom, whereas the floating roof is treated as an elastic plate undergoing large deflection. The contained liquid is assumed to be inviscid and incompressible, and the flow is assumed to be irrotational. The method of analysis is based on representation of the liquid motion by superposing the analytical modes that satisfy the Laplace equation and the rigid wall and bottom boundary conditions. The FEM is then applied to solve the remaining kinematic and dynamic boundary conditions at the moving liquid surface coupled with the nonlinear equation of motion of the floating roof. This requires only the discretization of the liquid surface and the floating roof into finite elements, thus leading to a computationally efficient and accurate method compared with full numerical analysis. As numerical examples to illustrate the applicability of the proposed method, two oil storage tanks with single‐deck type floating roofs damaged during the 2003 Tokachioki earthquake are studied. It is shown that the nonlinear oscillation modes with the circumferential wave numbers 0, 2 and 3 caused by the finite liquid surface elevation as well as the membrane action due to large deflection of the deck produce excessively large stresses in the pontoon, which may cause the catastrophic failure of pontoon followed by the submergence of the roof. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

In situ X-ray diffraction measurements of the <Emphasis Type="Italic">fcc</Emphasis>–<Emphasis Type="Italic">hcp</Emphasis> phase transition boundary of an Fe–Ni alloy in an internally heated diamond anvil cell     

Tetsuya?KomabayashiEmail author  Kei?Hirose  Yasuo?Ohishi 《Physics and Chemistry of Minerals》2012,39(4):329-338

The phase transition boundary between the face-centered cubic (fcc) structure and hexagonal close-packed (hcp) structure in an Fe–Ni alloy was determined at pressures from 25 to 107 GPa by using an internally resistive-heated diamond anvil cell (DAC), combined with in situ synchrotron X-ray diffraction measurements. The fcc–hcp phase transition boundary in Fe–9.7 wt% Ni is located at slightly lower temperatures than that in pure Fe, confirming the previous understanding that the addition of Ni expands the stability field of the fcc phase. The dP/dT slope of the boundary was determined to be 0.0426 GPa/K, which is slightly larger than that of pure Fe. The pressure interval of the two-phase region is about 6 GPa at a constant temperature, implying that the previous estimates by laser-heated DAC experiments of 10–20 GPa were overestimated. The two-phase region of fcc + hcp would be limited to a pressure of about 120 GPa even in Fe–15 wt%Ni, excluding the possibility of the existence of the fcc phase in the inner core if the simple linear extrapolation of the two-phase region is applied. The pressure and temperature dependences of the c/a axial ratio of the hcp phase in Fe–9.7 wt% Ni are generally consistent with those in pure Fe, suggesting that Ni has minor effects on the c/a ratio.  相似文献   

Evaluation of air-sea sensible and latent heat fluxes over the Japan Sea obtained from satellite,atmospheric reanalysis,and objective analysis products     

Hiroyuki Tomita  Tomoharu Senjyu  Masahisa Kubota 《Journal of Oceanography》2016,72(5):747-760

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Correction to: Synoptic conditions and potential causes of the extreme heavy rainfall event of January 2009 over Mindanao Island,Philippines     

Olaguera  Lyndon Mark Payanay  Caballar  Michelle Español  De Mata  Joseph Cabacungan  Dagami  Loida Ann Torres  Matsumoto  Jun  Kubota  Hisayuki 《Natural Hazards》2022,110(3):2405-2406

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