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11.
Akio Suzuki Eiji Ohtani Hidenori Terasaki Keisuke Nishida Hiromi Hayashi Tatsuya Sakamaki Yuki Shibazaki Takumi Kikegawa 《Physics and Chemistry of Minerals》2011,38(1):59-64
The viscosity of a silicate melt of composition NaAlSi2O6 was measured at pressures from 1.6 to 5.5 GPa and at temperatures from 1,350 to 1,880°C. We employed in situ falling sphere
viscometry using X-ray radiography. We found that the viscosity of the NaAlSi2O6 melt decreased with increasing pressure up to 2 GPa. The pressure dependence of viscosity is diminished above 2 GPa. By using
the relationship between the logarithm of viscosity and the reciprocal temperature, the activation energies for viscous flow
were calculated to be 3.7 ± 0.4 × 102 and 3.7 ± 0.5 × 102 kJ/mol at 2.2 and 2.9 GPa, respectively. 相似文献
12.
A number of slope failures during the 2004 Niigataken Chuetsu earthquake were investigated, revealing that the travel distance becomes longer as the slope gets gentler and the failed soil mass gets larger. An energy-based approach, proposed in previous research to evaluate the travel distance of failed slopes, is modified by adding the model test results and introducing a simple evaluation method. The energy approach is then applied to a number of slopes failed during the earthquake to back-calculate mobilized friction coefficients, revealing their strong dependency on initial slope inclinations. The friction coefficient was found to be smaller than the initial slope inclination for gentler slopes, indicating that the failed soil mass tends to accelerate. In contrast, that for steeper slopes was higher than initial slope inclination. The friction coefficient was found to decrease with increasing volume of failed slope, which is quite consistent with previous case studies including large non-seismic landslides. 相似文献
13.
Soma Kuwabara Hidenori Terasaki Keisuke Nishida Yuta Shimoyama Yusaku Takubo Yuji Higo Yuki Shibazaki Satoru Urakawa Kentaro Uesugi Akihisa Takeuchi Tadashi Kondo 《Physics and Chemistry of Minerals》2016,43(3):229-236
The sound velocity (V P) of liquid Fe–10 wt% Ni and Fe–10 wt% Ni–4 wt% C up to 6.6 GPa was studied using the ultrasonic pulse-echo method combined with synchrotron X-ray techniques. The obtained V P of liquid Fe–Ni is insensitive to temperature, whereas that of liquid Fe–Ni–C tends to decrease with increasing temperature. The V P values of both liquid Fe–Ni and Fe–Ni–C increase with pressure. Alloying with 10 wt% of Ni slightly reduces the V P of liquid Fe, whereas alloying with C is likely to increase the V P. However, a difference in V P between liquid Fe–Ni and Fe–Ni–C becomes to be smaller at higher temperature. By fitting the measured V P data with the Murnaghan equation of state, the adiabatic bulk modulus (K S0) and its pressure derivative (K S ′ ) were obtained to be K S0 = 103 GPa and K S ′ = 5.7 for liquid Fe–Ni and K S0 = 110 GPa and K S ′ = 7.6 for liquid Fe–Ni–C. The calculated density of liquid Fe–Ni–C using the obtained elastic parameters was consistent with the density values measured directly using the X-ray computed tomography technique. In the relation between the density (ρ) and sound velocity (V P) at 5 GPa (the lunar core condition), it was found that the effect of alloying Fe with Ni was that ρ increased mildly and V P decreased, whereas the effect of C dissolution was to decrease ρ but increase V P. In contrast, alloying with S significantly reduces both ρ and V P. Therefore, the effects of light elements (C and S) and Ni on the ρ and V P of liquid Fe are quite different under the lunar core conditions, providing a clue to constrain the light element in the lunar core by comparing with lunar seismic data. 相似文献
14.
Masato Naruse Tetsuya Ito Yutaro Sekimoto Hiroyuki Toba Naohisa Satou Masahiro Sugimoto Wenlei Shan Yoshizou Iizuka Toshiaki Kamba Mamoru Kamikura Yasutaka Serizawa 《Experimental Astronomy》2009,24(1-3):89-107
We have developed a near-field vector beam measurement system covering the range of frequencies from 385 to 500 GHz. The measurement set-up is capable of measurements with dynamic range exceeding 50 dB and amplitude and phase stability respectively of 0.1 dB/h and 1 degree/5 min at room temperature. Beam patterns of the ALMA band 8 corrugated horns and receiver optics block were measured at room temperature and lately compared with physical optics calculations obtained in the far-field. Both co-polar and cross-polar beam patterns of a qualification model of the ALMA band 8 cartridge cooled in a cartridge-test-cryostat have also been measured in the near-field as a detector of a submillimeter vector network analyzer. The measurements presented in this work refer to the lowest, middle and upper frequencies of band 8. The comparisons between software model and experimental measurements at these frequencies show good agreement down to ?30 dB for the main polarization component. The cross-polarization level of the beam propagating through the receiver optics block was also characterized. We found that a cross-polarization level better than ?28 dB can be achieved at all measured frequencies. The measured beam pattern of this receiver corresponds to efficiency of greater than 92% at the sub reflector (diameter of 750 mm) of the ALMA 12 m optics. 相似文献
15.
16.
Etching conditions and thermal annealing effects have been studied for fission tracks in four kinds of zircons. The observation of fission tracks under an optical microscope was made with respect to the mean pit length as well as the mean pit density. Apparent rate constants were obtained by substituting the isochronal (60 minutes) annealing data into the ordinary equation of the rate constant. The order of reaction (almost 3rd or 4th) and the activation energy (1.7–2.9 eV) of annealing were determined from the Arrhenius plot of the apparent rate constants. 相似文献
17.
Norio Hori Norio Inoue Dangol Purushotam Tetsuya Nishida Jun Kobayashi 《地震工程与结构动力学》2006,35(13):1699-1719
To improve the seismic performance of masonry structures, confined masonry that improves the seismic resistance of masonry structures by the confining effect of surrounding bond beams and tie columns is constructed. This study investigated the earthquake resisting behaviour of confined masonry structures that are being studied and constructed in China. The structural system consists of unreinforced block masonry walls with surrounding reinforced concrete bond beams and tie columns. The characteristics of the structure include: (1) damage to blocks is reduced and brittle failure is avoided by the comparatively lower strength of the joint mortar than that of the blocks, (2) the masonry walls and surrounding reinforced concrete bond beams and tie columns are securely jointed by the shear keys of the tie columns. In this study, wall specimens made of concrete blocks were tested under a cyclic lateral load and simulated by a rigid body spring model that models non‐linear behaviour by rigid bodies and boundary springs. The results of studies outline the resisting mechanism, indicating that a rigid body spring model is considered appropriate for analysing this type of structure. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
18.
Tsutsumi S Yamaguchi Y Nishida I Akiyama K Zakaria MP Takada H 《Marine pollution bulletin》2002,45(1-12):325-331
Alkylbenzenes, molecular markers of sewage, were measured in 34 green mussels collected from India, Indonesia, Malaysia, Thailand, Cambodia, Vietnam, and the Philippines together with blue mussels collected from Tokyo Bay, Japan. Linear alkylbenzene (LAB) concentrations in South and South East Asian countries ranged from 10 to 1640 ng-∑LAB/g-dry tissue. In some populous cities, LAB concentrations were similar or higher than those found in northern Tokyo Bay which is heavily impacted by sewage effluents. I/E ratios (a ratio of internal to external isomers of LABs) in the South and South East Asian countries (1–3) were much lower than those in Tokyo Bay (3–8), indicating sewage discharged in the coastal zone is poorly treated (e.g., raw sewage and/or primary effluents). Alkylbenzenes with branched alkyl chains, tetrapropylene-based alkylbenzenes, were also detected in mussels from Indonesia and Philippines. This “tell-tale” sign indicates that poorly degradable detergents are still in use in this area, although they have long been phased-out in many industrialized countries. 相似文献
19.
The relationship between the relativistic electron bursts (0.3 ~ 1.0 MeV) observed in the magnetotail at X = ?20 ~ ?30 Re and the evolution of the structure of the magnetotail during substorms is investigated. It is found that the majority of the relativistic electron bursts are associated with the substorm activity and occurs inside the plasma sheet at the time of the local BZ-southward turning. It is suggested that these electrons are accelerated at the neutral line and trapped in the magnetic loop structure. 相似文献
20.