Seismic-response-controlled structure with active mass driver system. Part 2: Verification     

Takuji Kobori  Norihide Koshika  Kazuhiko Yamada  Yoshiki Ikeda 《地震工程与结构动力学》1991,20(2):151-166

An Active Mass Driver (AMD) system is proposed to suppress actively the response of a building to irregular external excitations such as earthquakes and typhoons.¹ This system has been introduced to an actual ten-storey office building constructed in Tokyo in August, 1989. The proposed analytical methods utilize circuits of the system and mechanical characteristics to understand the real control effect of the system. Simulation analyses are also performed to verify the analytical model and the control effect during observed earthquakes.  相似文献   

Synthesis of kosmochlor and phase equilibria in the join CaMgSi2O6-NaCrSi2O6     

Ko Ikeda  Kenzo Yagi 《Contributions to Mineralogy and Petrology》1972,36(1):63-72

Kosmochlor (NaCrSi₂O₆) was synthesized by the flux method from melts along the join Na₂O·2 SiO₂-Na₂O·Cr₂O₃·4 SiO₂ at 1000° C in air, and isolated by dissolving the glassy matrix with hydrofluoric and perchloric acids. The join CaMgSi₂O₆-NaCrSi₂O₆ was studied at 1 atmosphere in air by the quenching technique at temperatures between 900° and 1450° C, using mixtures of kosmochlor and diopside crystals or diopside glass as starting materials. The phases are diopside solid solution, kosmochlor, spinel (Mg-chromite), eskolaite (Cr₂O₃) and glass. The maximum solubility of kosmochlor in diopside is 24 wt percent at 1140° C, while diopside is not soluble at all in kosmochlor, resulting in the existence of a wide range of immiscibility. Petrologic significance of the results is discussed.  相似文献   

Stationary Rossby-waves in a two-layer model produced by a submarine ridge     

Motoyoshi Ikeda 《Journal of Oceanography》1979,35(2):100-109

Characteristics of stationary Rossby-waves are investigated by use of equations expressing conservation of potential vorticity for a quasi-geostrophic two-layer flow of an incompressible inviscid fluid on a beta-plane. A two-dimensional problem is discussed; the basic flow is directing eastward without horizontal shear, and the stationary Rossby-waves are produced by a two-dimensional bump extending in the north-south direction which is located on a sloping bottom with a constant north-south gradient.When the slope is steep, stream-lines are scarcely displaced being influenced by the bump. When the bottom has no north-south inclination, however, there is a case where group velocity of Rossby-waves produced by the bump directs westward and the stream-lines meander sinusoidally at the west of the bump. This phenomenon is called upstream influence. These two special cases have a possibility to explain two different mean paths for the Kuroshio namely, the path along the continental slope and the path with a stationary meander at the west of the Izu-Ogasawara Ridge.  相似文献   

Cases-97: Late-Morning Warming And Moistening Of The Convective Boundary Layer Over The Walnut River Watershed     

Margaret A. LeMone  Robert L. Grossman  Robert T. Mcmillen  Kuo-Nan Liou  S.C. Ou  Stuart Mckeen  Wayne Angevine  Kyoko Ikeda  Fei Chen 《Boundary-Layer Meteorology》2002,104(1):1-52

Aircraft, radiosonde, surface-flux, and boundary-layer windprofiler data from the Cooperative Atmosphere Surface Exchange Study's 1997 field project, CASES-97, are combined with synoptic data to study the evolution of the vertically-averaged mixed-layerpotential temperature []and mixing-ratio [Q] onthree nearly-cloudless days from 1000 CST to 1200CST (local noon is approximately 1230 CST). This was achieved through examination of the terms in the time-tendency (`budget')equations for []and [Q]. We estimate three of the terms –local time rate of change, vertical flux divergence, andhorizontal advection. For the [Q]-budget, vertical flux divergence usually dominates, buthorizontal advection is significant on one of the three days. The [Q]-budget balances for two of the three days to within the large experimental error. For the -budget,vertical flux divergence accounts for most of the morningwarming, with horizontal advection of secondary importance.The residual in the -budget has the same sign for all three days, indicating that not all the heating is accounted for. We can balance the []-budgets to within experimental error on two of the three days by correcting the vertical-flux divergence for apparent low biases in the flux measurements of one of the aircraft and in the surface fluxes, and accounting for direct heating of the mixed layer by radiative flux divergence allowing for the effects of carbonaceous aerosols. The [];-budget with these corrections also balances on the third day if horizontal gradients from synoptic maps are used to estimate the horizontal advection. However, the corrected budget for this day does not balance if the horizontal gradient in the advection term is estimated using CASES-97aircraft and radiosondes; we suggest that persistent mesoscale circulations led to an overestimate of the horizontal gradient andhence horizontal advection.  相似文献   

Damage process of pile foundation in liquefied ground during strong ground motion   总被引：1，自引：0，他引：1  

S. Miwa  T. Ikeda  T. Sato 《Soil Dynamics and Earthquake Engineering》2006,26(2-4):325-336

The 1995 Hyogoken–Nambu earthquake caused severe liquefaction over wide areas of reclaimed land. Furthermore, the liquefaction induced large ground displacement in horizontal directions, which caused serious damage to foundations of structures. However, few analyses of steel pipe piles based on field investigation have so far been conducted to identify the causes and process of such damage. The authors conducted a soil–pile-structure interaction analysis by applying a multi-lumped-mass-spring model to a steel pipe pile foundation structure to evaluate the causes and process of its damage. The damage process analyzed in the time domain corresponded well with the results of detailed field investigation. It was found that a large bending moment beyond the ultimate plastic moment of the pile foundation structure was induced mainly by the large ground displacement caused by liquefaction before lateral spreading of the ground and that the displacement appeared during the accumulating process of the excess pore water pressure.  相似文献   

安宁河断裂带晚第四纪运动特征及模式的讨论   总被引：12，自引：1，他引：12       下载免费PDF全文

何宏林  池田安隆 《地震学报》2007,29(5):537-548

安宁河断裂带是中国西南地区一条重要的地震活动断层， 地方志记载公元1536年曾发生过震级大于7级的破坏性地震. 详细的断裂地貌航片解译和野外调查表明， 安宁河断裂带除具有主要的左旋走滑断层活动外，还兼有重要的逆冲运动分量. 根据冲沟和阶地面的位错量及其热释光测年结果估计，该断裂带晚更新世以来平均左旋走滑速率为3~7 mm/a. 根据滑移方向与断层走向的关系，推测跨安宁河断裂带东西向由于逆冲断层运动造成的挤压缩短速率约为1.7~4.0 mm/a； 简单分解鲜水河断裂带上的滑动速率，估计分配在大凉山断裂带上的滑动速率与安宁河断裂带上的大致相当，约为3~7 mm/a. 此外，根据野外调查结果，并结合最近青藏高原构造动力学研究的新认识， 建立了安宁河断裂带的动力学模型，认为安宁河断裂带是一条逆冲走滑断裂带. 其下盘（西盘）主动向南东方向下插，造成了上盘（东盘）向北西方向的上冲运动.   相似文献   

Recent climatic change and unusual weather in the Northern Hemisphere     

T. Asakura Dr.  S. Ikeda Dr. 《GeoJournal》1981,5(2):113-116

Occurrence frequency of unusual weather caused by anomalous synoptic patterns has its peaks in the middle latitude regions and the subtropical regions. Height anomaly patterns at the 500 mb level for the last three decades show the expansion of negative area in the northern hemisphere, resulting in increase of variability in space and time.  相似文献   

Rare-earth and trace elements in the Quaternary volcanic rocks of Hokkaido,Japan     

Yasuyuki Masuda  Susumu Nishimura  Takashi Ikeda  Yoshio Katsui 《Chemical Geology》1975,15(4):251-271

Seven rare-earth elements (La, Ce, Sm, Eu, Tb, Yb, Lu) and Co, Cr, Sc, Ba, Hf and Th have been determined by non-destructive neutron activation analysis on the Quaternary volcanic rocks in Hokkaido, Japan. The trace-element abundances are discussed in terms of the petrological problems, particularly the origin of calc-alkali magma. On the basis of the La/Sm ratio and the contents of K, Ba, Th and La, lateral variations in the contents of trace elements exist across the Kurile and the northern Honshū arcs. The calc-alkali rocks can be classified into three types which correspond to Kuno's three basalt-magma types. There is no essential difference in the rare-earth patterns between the basaltic rocks and the associated calc-alkali rocks in each petrographic province. This suggests that the calcalkali rocks may be derived from the basaltic magmas by fractional crystallization under certain conditions.  相似文献   

Experimental study on the phase equilibria in the join CaMgSi2O6-CaCrCrSiO6 with special reference to the blue diopside     

Ko Ikeda  Kenzo Yagi 《Contributions to Mineralogy and Petrology》1977,61(1):91-106

The behaviour of tetrahedrally coordinated and octahedrally coordinated Cr³⁺ ions in diopside is discussed from the study on the join CaMg-Si₂O₆-CaCrCrSiO₆. The molecule CaCrCrSiO₆ decomposes into uvarovite+eskolaite and its maximum solubility in diopside is 6.7 wt percent at 940 ° C. Crystalline phases are diopside ss (ss is abbreviation of solid solution), uvarovite ss, wollastonite ss, spinel and eskolaite. The diopside ss is blue in colour. Its optical spectra were measured in the wavelenght range of 325–2600 nm, and assigned after tetrahedral configuration Td and octahedral configuration Oh. It is estimated that octahedral Cr³⁺ ions are in high spin state, while tetrahedral Cr³⁺ ions may be probably in low spin state. The _t and B are 10,300–10,370 cm^–1 and 429–432 cm^–1. The CFSE for tetrahedral low spin Cr³⁺ ions is nearly the same as that for octahedral high spin Cr³⁺ ions. The ionic radii of tetrahedral low spin Cr³⁺ ions calculated are 0.47–0.53 Å, shrinked from the radius of octahedral high spin Cr³⁺ ion (0.615 Å) as much as 14–24 percent. Petrologic implications of the result are also discussed.The first half of the D. Sc. dissertation of K. Ikeda presented to Hokkaido University in June, 1976  相似文献   

Modeling Arctic Ocean heat transport and warming episodes in the 20th century caused by the intruding Atlantic Water     

Jun Takahashi  Tatsuo Suzuki  Igor V Polyakov  Kohei Mizobata  Moto Ikeda  Fancois J.Saucier  Markus Meier 《极地研究(英文版)》2008,19(2):159-167

This study investigates the Arctic Ocean warming episodes in the 20th century using both a high-resolution coupled global climate model and historical observations. The model, with no flux adjustment, reproduces well the Atlantic Water core temperature （AWCT） in the Arctic Ocean and shows that four largest decadalscale warming episodes occurred in the 1930s, 70s, 80s, and 90s, in agreement with the hydrographic observational data. The difference is that there was no pre-warming prior to the 1930s episode, while there were two pre-warming episodes in the 1970s and 80s prior to the 1990s, leading the 1990s into the largest and prolonged warming in the 20th century. Over the last century, the simulated heat transport via Fram Strait and the Barents Sea was estimated to be, on average, 31.32 TW and 14.82 TW, respectively, while the Bering Strait also provides 15.94 TW heat into the west- ern Arctic Ocean. Heat transport into the Arctic Ocean by the Atlantic Water via Fram Strait and the Barents Sea correlates significantly with AWCT （ C = 0.75 ） at 0- lag. The modeled North Atlantic Oscillation （NAO） index has a significant correlation with the heat transport （ C = 0.37 ）. The observed AWCT has a significant correlation with both the modeled AWCT （ C =0.49） and the heat transport （ C =0.41 ）. However, the modeled NAO index does not significantly correlate with either the observed AWCT （ C = 0.03 ） or modeled AWCT （ C = 0.16 ） at a zero-lag, indicating that the Arctic climate system is far more complex than expected.  相似文献