Failure of double friction pendulum bearings under pulse‐type motions          下载免费PDF全文

Yu Bao  Tracy C. Becker  Hiroki Hamaguchi 《地震工程与结构动力学》2017,46(5):715-732

Although the behavior of friction sliding bearings is well understood, the failure behavior has not been thoroughly investigated. However, predicting and understanding the failure of bearings is an important key in designing isolated structures to minimize their collapse in extreme events, and thus, this study is critical. Because of its relative simplicity and particular availability in certain markets, the failure of the double friction pendulum (DFP) bearing at its physical displacement limit is investigated. The bearing is modeled with a rigid body model including inertia for each of the bearing components. A nonlinear viscoelastic impact model is included to simulate the impact between bearing components. As isolation systems are particularly vulnerable to long‐period excitations, analytical pulses are used as input excitations to investigate the influences of pulse parameters on the failure of DFP. The influences of DFP design parameters are investigated as well. To confirm that the response to the analytical pulses correctly represents the behavior under long‐period ground motions, wavelet analysis to is performed on 14 pairs of pulse‐type ground motion records to extract their pulses, and the failure prediction made from the extracted analytical pulse is compared with the failure from the real ground motions. It is found that using the extracted pulses provides a good estimation for the failure prediction of the ground motions. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Crustal structure of central Japan and its petrological implications     

Oguz Ozel  Takaya Iwasaki  Takeo Moriya  Shin'ichi Sakai  Takuya Maeda  Chengshi Piao  Toshikatsu Yoshii  Shinya Tsukada  Akihito Ito  Masayuki Suzuki  Akira Yamazaki  & Hiroki Miyamachi 《Geophysical Journal International》1999,138(1):257-274

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二噁英引起斑马鱼下颌短小及其与Sonic hedgehog基因的关联   总被引：2，自引：0，他引：2  

董武  杨景峰  曹颖霞  王思珍  Hiroki Teraok  Takeo Hiraga 《湖泊科学》2005,17(2):162-168

环境污染物二噁英中毒性最强的2,3,7,8-四氯二苯并对二噁英(2,3,7,8-tetrachlorodibenzo-p-dioxin,以下简称TCDD)经由芳烃基受体(aryl hydrocarbon receptor,Ahr)引起啮齿类口唇开裂,斑马鱼下颌短小等典型特征,本试验研究了TCDD引起的下颌短小与形态发育基因Sonic hedgehog(shh)的关系,用0-1．0μg／L的TCDD给受精后24h(24hpf)的斑马鱼胚染毒直至观察并进行形态学观察及原位杂交,结果观察到TCDD引起斑马鱼的下颌短小与其浓度相依存．同时观察到TCDD染毒群的Shh基因表达以及类似基因tiggy-winkle hedgehog(twhh)的低下．观察Shh缺失的斑马鱼变异体Syu,或给正常斑马鱼染毒,添加Shh阻断药Cycopamant Cyclopamine,可以同样观察到斑马鱼的下颌短小,本试验表明TCDD引起的下颌短小与shh和twhh表达是相关联的．同时也说明斑马鱼有可能作为二噁英类污染物的生物学毒性评价生物。  相似文献   

The proximal facies of the Tosu pyroclastic-flow deposit erupted from Aso caldera,Japan     

Keiko Suzuki-Kamata  Hiroki Kamata 《Bulletin of Volcanology》1990,52(5):325-333

The Tosu pyroclastic flow deposit, a low-aspect-ratio ignimbrite (LARI), has widely distributed breccia facies around Aso caldera, Japan. The proximal facies, 9–34 km away from the source, consists of 3 different lithofacies, from bottom to top: a lithic-enriched and fines-depleted (FD) facies, a lithic-enriched (LI) facies with an ash matrix, and a fines- and pumice-enriched (NI) facies. Modes of emplacement of FD, LI, and NI are interpreted as ground layer, 2b-lithic-concentration zone, and normal ignimbrite, respectively. These stratigraphic components in the Tosu originated from the flow head (FD) and the flow body (LI and NI), and were generated by a single column collapse event. Remarkably thick FD and LI, in contrast to thin NI, suggest that due to high mobility most ash and punice fragments in the Tosu were carried and deposited as NI in the distal area. Heavier components were selectively deposited as FD and LI in the proximal area. The rate of falloff of lithic-clast size in the Tosu shows an inflection at 20 km from the source. In a survey of well-documented pyroclastic flows, the inflection distance of a LARI is generally greater than that of a high-aspect-ratio ignimbrite, so that the eruption of the former is probably more intense than the latter.  相似文献   

Partitioning Eddy-Covariance Methane Fluxes from a Shallow Lake into Diffusive and Ebullitive Fluxes   总被引：1，自引：0，他引：1  

Hiroki Iwata  Ryuichi Hirata  Yoshiyuki Takahashi  Yuichi Miyabara  Masayuki Itoh  Kotaro Iizuka 《Boundary-Layer Meteorology》2018,169(3):413-428

Methane (\(\mathrm {CH}_{4}\)) is known to be emitted from lakes to the atmosphere via processes such as diffusion and ebullition (i.e., bubble emission). We developed a practical method for partitioning eddy-covariance \(\mathrm {CH}_{4}\) fluxes from a shallow lake into diffusive and ebullitive fluxes using a wavelet analysis based on local scalar similarity between the \(\mathrm {CH}_{4}\) concentration and other reference scalars, such as the air temperature or water vapour concentration, in the wavelet time-scale domain, with the hypothesis that similar and dissimilar fluctuation components are related to diffusive and ebullitive \(\mathrm {CH}_{4}\) fluxes, respectively. Our method is applied to approximately two weeks of data obtained at a shallow mid-latitude lake. The partitioned diffusive flux has a physically sound relationship with wind speed, supporting the validity of the method. The ratio of the diffusive flux to the total flux is typically 0.11 with flow from an area of steady bubble emission, but otherwise 0.36. Further validation is required using a larger dataset and data from other lakes. The proposed method can be easily applied to historical data because it requires only 10-Hz data of \(\mathrm {CH}_{4}\) concentration and other reference scalars, along with an empirical parameter.  相似文献   

Study of evapotranspiration and evaporation beneath the canopy in a buckwheat field   总被引：2，自引：0，他引：2  

Haofang Yan  Chuan Zhang  Hiroki Oue  Guoqing Wang  Bin He 《Theoretical and Applied Climatology》2015,122(3-4):721-728

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Seismic experiments on Showa-Shinzan lava dome using firework shots     

Hiroki Miyamachi  Hidefumi Watanabe  Takeo Moriya  Hiromu Okada 《Pure and Applied Geophysics》1987,125(6):1025-1037

Seismic experiments were conducted on Showa-Shinzan, a parasitic lava dome of volcano Usu, Hokkaido, which was formed during 1943–1945 activity. Since we found that firework shots fired on the ground can effectively produce seismic waves, we placed many seismometers on and around the dome during the summer festivals in 1984 and 1985. The internal structure had been previously studied using a prospecting technique employing dynamite blasts in 1954. The measured interval velocity across the dome in 1984 ranges 1.8–2.2 km/s drastically low compared to the results (3.0–4.0 km/s) in 1954; in addition, the velocity is 0.3–0.5 km/s higher than that in the surrounding area. The variation of the observed first arrival amplitudes can be explained by geometrical spreading in the high velocity lava dome. These observations show a marked change in the internal physical state of the dome corresponding to a drop in the measured highest temperature at fumaroles on the dome from 800°C in 1947 to 310°C in 1986.  相似文献   

Rotating eruption of an untwisting filament triggered by the 3B flare of 25 April, 1984     

Hiroki Kurokawa  Yoichiro Hanaoka  Kazunari Shibata  Yutaka Uchida 《Solar physics》1987,108(2):251-264

A great 3B flare, whose X-ray class was X13, occurred over a delta-sunspot at 00: 01 UT on April 25, 1984. Before the flare, a strong magnetic shear was found to be formed along the neutral line in the delta-sunspot with shear motions of umbrae. The shear motions of the umbrae were caused by the successive emergence of a magnetic flux rope.Before the flare, several groups of sheared H threads and filaments were found to merge into an elongated filament along the neutral line through the delta-sunspot. In the merging process the helical twists were formed in the filament by the reconnection as in the Pneuman's (1983) model.At the post-maximum phase of the flare, the helically twisted filament spouted out with an untwisting rotation. Examining the morphological and dynamical features of the filament eruption, we concluded that it has some typical features of the flare spray and that it seems to be accelerated by the sweeping-magnetictwist mechanism proposed by Shibata and Uchida (1986).Contributions from the Kwasan and Hida Observatories, University of Kyoto, No. 276.  相似文献   

The coronal condensation observed at the 1973 eclipse     

Hiroki Kurokawa 《Solar physics》1975,43(2):385-403

The flash spectrograms obtained at the June 30, 1973 eclipse contain the monochromatic images of a coronal condensation in three coronal lines of Fexiv 5303, Fex 6374 and Fexi 7892 and Hα line. The assumption of the axially-symmetric distribution of the emissivity in the coronal lines allows us to find the density and temperature structure of the coronal condensation. While the electron density in the central axis of the condensation is about ten times as high as that of the normal corona at each height, the temperature is not so high (T?2.3×10⁶K). This seems to be a representative nature of a coronal active region in the post maximum phase of activity. It is found that there exists a cool and dense core (T = 10⁶K, N _e =6 × 10⁹ cm^-3 at 17000 km) at the lower part of the coronal condensation, which is in a close geometrical coincidence with the small active prominence protruding from the underlying plage region.  相似文献   

Middle Miocene to Pleistocene magneto-biostratigraphy of ODP Sites 1150 and 1151, northwest Pacific: Sedimentation rate and updated regional geological timescale     

Isao Motoyama  Nobuaki Niitsuma  Toshiaki Maruyama  Hiroki Hayashi  Shin-ichi Kamikuri  Masamichi Shiono  Toshiya Kanamatsu  Kaori Aoki  Chikako Morishita  Kyoko Hagino  Hiroshi Nishi  Motoyoshi Oda 《Island Arc》2004,13(1):289-305

Abstract Shipboard and shore‐based investigation on siliceous and calcareous microfossil biostratigraphy, magneto‐stratigraphy and tephrostratigraphy identified numerous datum events from the sedimentary sequences of Sites 1150 and 1151 drilled on the forearc basin of northern Japan by the Ocean Drilling Program Leg 186. Some 83 datum events were selected to construct new age–depth models for the sites. Based on the reliable magneto‐stratigraphy from the Pleistocene to the Upper Miocene, which were correlated to the standard geomagnetic polarity timescale, and on excellent records of diatom and radiolarian biostratigraphy throughout the sequences, the shipboard age model was revised. Major revisions referred to stratigraphic position of the Miocene–Pliocene boundary that has been shifted more than 200 m downward in each sequence. The age–depth relations of the forearc sites represent drastic changes in the sedimentation rate—extremely high (40 cm/k.y. on average) in the Early Pliocene and low (less than 2 cm/k.y. on average) in the Middle Miocene—and several hiatuses exist throughout the sequence. The drastic changes can be related mostly to changes in diatom sedimentation and the tectonics of the Japanese Island Arc. Local ages for some foraminiferal, calcareous nannofossil and radiolarian bioevents are estimated from the age–depth models at each site. These newly calibrated bioevents and biozones as well as established diatom biostratigraphy are incorporated into the updated magneto‐biochronologic timescale, which will contribute to an improvement in biochronologic accuracy of Neogene sediments in northern Japan and adjacent areas.  相似文献