Interaction between waves and an array of floating porous circular cylinders   总被引：1，自引：0，他引：1  

赵芬芳  鲍伟光  黄六一  梁振林  万荣 《中国海洋工程》2012,26(3):397-412

The present study theoretically as well as experimentally investigates the interaction between waves and an array of porous circular cylinders with or without an inner porous plate based on the linear wave theory.To design more effective floating breakwaters,the transmission rate of waves propagating through the array is evaluated.Each cylinder in the array is partly made of porous materials.Specifically,it possesses a porous sidewall and an impermeable bottom.In addition,an inner porous plate is horizontally fixed inside the cylinders.It dissipates the wave more effectively and eliminates the sloshing phenomenon.The approach suggested by Kagemoto and Yue(1986) is adopted to solve the multiple-scatter problem,while a hierarchical interaction theory is adopted to deal with hydrodynamic interactions among a great number of bodies,which efficiently saves computation time.Meanwhile,a series of model tests with an array of porous cylinders is performed in a wave basin to validate the theoretical work and the calculated results.The draft of the cylinders,the location of the inner porous plate,and the spacing between adjacent cylinders are also adjusted to investigate their effects on wave dissipation.  相似文献   

The dynamical architecture and habitable zones of the quintuplet planetary system 55 Cancri     

Jiang-Hui Ji Hiroshi Kinoshita Lin Liu Guang-Yu Li 《天体物理学报》2009,(6):703-711

We perform numerical simulations to study the secular orbital evolution and dynamical structure of the quintuplet planetary system 55 Cancri with the self-consistent orbital solutions by Fischer and coworkers. In the simulations, we show that this system can be stable for at least 108 yr. In addition, we extensively investigate the planetary configuration of four outer companions with one terrestrial planet in the wide region of 0.790AU 〈 a 〈 5.900AU to examine the existence of potential asteroid structure and Habitable Zones （HZs）. We show that there are unstable regions for orbits about 4：1, 3：1 and 5：2 mean motion resonances （MMRs） of the outermost planet in the system, and several stable orbits can remain at 3：2 and 1：1 MMRs, which resembles the asteroid belt in the solar system. From a dynamical viewpoint, proper HZ candidates for the existence of more potential terrestrial planets reside in the wide area between 1.0 AU and 2.3 AU with relatively low eccentricities.  相似文献   

Periodic solutions of the third sort for restricted problem of three bodies and their stability     

Yoshihide Kozai  Hiroshi Kinoshita 《Celestial Mechanics and Dynamical Astronomy》1973,7(2):156-176

In this paper periodic solutions of the third sort for restricted problem of three bodies in the three-dimensional space are derived numerically by starting from generating solutions obtained by one of the authors (1969) and by increasing the mass-ratio of the two primaries stepwise from zero to about 1000 for 21, 32 and 61 cases of commensurable mean motions. Periodic solutions both for circular and elliptic orbits of the primaries are obtained.The stability of the periodic solutions for the 21 circular case is discussed and it is found that none of them is linearly stable.  相似文献   

Nonuniform Distribution Of High-Frequency Turbulence In The Unstable Boundary Layer     

Nobuyuki Kinoshita 《Boundary-Layer Meteorology》2003,106(1):61-91

Turbulent flow data of wind velocity and temperature in the unstably stratifiedatmospheric boundary layer, derived from steel tower observations in the field and wind-tunnel experiments were used to study the relationship between the plumes and the small-scale eddies in the inertial subrange. Flow visualisation experiments in the wind tunnel were also conducted to observe the structure of the flow in the plumes, and time series data were analysed by using wavelet transforms. The results show that variances of velocity and temperature due to the small-scale eddies are large in the plumes and small outside of the plumes, and that the momentum and heat fluxes due to the small-scale eddies follow the same tendency as found in the variances. The ratios of the variances caused by the small-scale eddies in the plumes to the whole of the variances caused by the small-scale eddies in and out the plumes increase with non-dimensional height -z/L in which L is the local Obukhov length. Similar ratios of the fluxes caused by the small-scale eddies also show the same tendency. These ratios can be expressed as functions of -z/L for results based on field observationand the wind tunnel experiments. This relation hardly changes even if the wavelet function is changed. The flow visualisation experiments show that the plumes have a complicated structure in which mushroom type flows are stacked on top of each other. This characteristic structure seems to increase the energy of the small-scale eddies in the plumes.  相似文献   

Damage to Residential Fills in the 1995 Hanshin-Awaji Earthquake     

Nobuyuki Yoshida  Masaru Nishi  Mitsuhiro Nanbu 《Natural Hazards》2001,23(1):87-97

This paper summarizes the features of ground damage toresidential fills due to the 1995 Hyogo-ken NanbuEarthquake in Japan. Many residential lands sufferedground damage to various extents in the earthquakeevent. Permanent deformation took place ingently-sloping residential fills. Some slopes asgentle as four degrees exhibited landslide-likedownward movements from dozens to hundreds ofcentimeters, so on. It is suggested that liquefactionmight be a dominant factor for displacements ingently-inclined residential fills.  相似文献   

山西高原六棱山北麓断裂晚第四纪运动学特征初步研究   总被引：14，自引：5，他引：14       下载免费PDF全文

邓起东  米仓伸之 《地震地质》1994,16(4):339-343

六棱山北麓断裂是山西地堑系北端张性构造区中的一条控制性断裂，总体走向北东东、倾向北北西，是一条至今仍在活动的倾滑正断裂，控制阳原盆地的形成和发展。在１９９３年和１９９４年的中日合作研究中，我们对断裂分段特征进行了研究，并用Ａｕｔｏ－ｌｅｖｅｌ仪器对这一条断裂晚第四纪不同时期的断错地貌面的位错量进行了测量，对这些地貌面的年龄进行了测定，得到该断裂带晚更新世晚期至全新世时期的平均垂直滑动速率为０．４３～０．７５ｍｍ／ａ。关键词  相似文献   

Concentration mechanisms of iron oxides and alumina in deep weathering crusts (Goshikidai, Kagawa, Western Japan)     

Hideo Minato  Akira Tokuyama  Nobuyuki Sasaki 《Chemical Geology》1987,60(1-4):73-78

Concentration of Fe-oxides and alumina in weathering processes are main geological reactions for lateritization and bauxitization, respectively. In western Japan, red-coloured soil formed by weathering processes developed in many places. This soil is composed of hydrous Fe-oxide minerals, hydrous alumina minerals and other minerals. It was formed in the upper part of deep weathering crust by weathering processes under some kind of sub-tropical climate, probably in the Pliocene. One of these occurrences is observed in the upper part of Goshikidai and Konodai, west part of Takamatsu city, northeast Shikoku Island, west Japan. A deep weathering crust is distributed on wide hilly plains ranging from 250 to 400 m a.m.s.l. in the northwestern region of Takamatsu city. Original rock of the weathering crust is bronzite andesite and glassy bronzite andesite, so-called ‘sanukite’. The andesites had been weathered under some special climate, and the geological age of the weathering is the same as above. The mineral assemblage and formation mechanism are similar to those of laterite and bauxite. The weathering crust developing in this region are subdivided into the three following zones: (1) A zone, composed of hydrous Fe-oxides and metahalloysite with small amounts of gibbsite and it is associated with white veins of metahalloysite; (2) B zone, composed of hydrous Fe-oxides and metahalloysite (some material is associated with -cristobalite); and C zone, composed of metahalloysite or halloysite and -cristobalite with relict crystals of feldspar and quartz, and some material is associated with montmorillonite. Chemical analyses of the materials of the three zones show the formation mechanisms of the weathering crust.  相似文献   

Electron probe microanalysis study on processes of low-temperature oxidation of titanomagnetite     

Takatoshi Akimoto  Hajimu Kinoshita  Toshio Furuta 《Earth and Planetary Science Letters》1984,71(2):263-278

Partially oxidized titanomagnetite grains in various kinds of volcanic rocks were investigated by electron probe microanalyzer (EPMA) in order to clarify the process of oxidation at low temperature. The following results were obtained by the present investigation: (1) Primary composition of titanomagnetite is homogeneous in individual grains, although variation in composition among different grains is observed on each thin section. (2) Migration of Fe cations during low-temperature oxidation is clearly seen in all oxidized grains. Some other constituent cations are also bleached and consequently the relative content of the remaining cations becomes large. (3) The detailed internal structures of titanomagnetite grains are observed as backscattered electron images (BEI) with an electronprobe microanalyzer, and it seems likely that the structures depend upon the degree of low-temperature oxidation. (4) The chemical and physical properties of oxidized titanomagnetites imply that low-temperature oxidation is not a simple process but a complex one. Such an oxidation process is correlatable to both the mobility of cation and the oxidation condition such as a circulation of some active hydrothermal materials at low temperature.  相似文献   

Placental transfer of arsenic to fetus of Dall's porpoises (Phocoenoides dalli)     

Kubota R  Kunito T  Fujihara J  Tanabe S  Yang J  Miyazaki N 《Marine pollution bulletin》2005,51(8-12):845-849

Concentrations of total arsenic and individual arsenic compounds were determined in liver, muscle, kidney and blubber of mother and fetus of Dall’s porpoises collected from off Sanriku, Japan, in the year 2000 to characterize the placental transfer of arsenic to fetus in cetaceans. Arsenic was detected in all the tissues of Dall’s porpoises. Total arsenic concentrations in liver, kidney, muscle and blubber were 0.76, 0.69, 0.35 and 0.55 μg/g wet wt, respectively, for mother and 0.28, 0.23, 0.26 and 0.07 μg/g wet wt, respectively, for fetus. In all the tissues, concentrations of total arsenic in mother Dall’s porpoise were higher than in fetus. Arsenic speciation revealed that arsenobetaine was the major arsenic compound in liver, kidney and muscle of both mother and fetus. The percentage of arsenobetaine to total arsenic ranged from 76.0 to 91.0% in the tissues. Dimethylarsinic acid, arsenocholine, methylarsonic acid and an unidentified arsenic compound were also detected in tissues of both mother and fetus as minor constituents, whereas tetramethylarsonium ion was not detected in tissues of the fetus. These results suggest that arsenobetaine, dimethylarsinic acid, arsenocholine and methylarsonic acid are transferable from mother to fetus in Dall’s porpoises. To our knowledge, this is the first report on placental transfer of arsenic compounds to fetus in marine mammals.  相似文献   

Mars theory and its comparison with numerical integration     

Hiroshi Kinoshita  Hiroshi Nakai 《Celestial Mechanics and Dynamical Astronomy》1982,26(2):169-169

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