FMC cameras,high resolution films and very large scale mapping     

Kikuo Tachibana  Hiroyuki Hasegawa 《国际地球制图》2013,28(2):73-79

Abstract

Very large scale mapping (1/250) was experimented on the basis of FMC camera, high resolution film and total station surveying.

The future attractive combination of precision photogrammetry and personal computer assisted terrestrial surveying was investigated from the point of view of accuracy, time effectiveness and total procedures control.  相似文献   

Mass dispersal and angular momentum transfer during collisions between rubble-pile asteroids     

Takaaki Takeda  Keiji Ohtsuki 《Icarus》2007,189(1):256-273

We perform N-body simulations of impacts between initially non-rotating rubble-pile asteroids, and investigate mass dispersal and angular momentum transfer during such collisions. We find that the fraction of the dispersed mass (Mdisp) is approximately proportional to , where Qimp is the impact kinetic energy; the power index α is about unity when the impactor is much smaller than the target, and 0.5?α<1 for impacts with a larger impactor. Mdisp is found to be smaller for more dissipative impacts with small values of the restitution coefficient of the constituent particles. We also find that the efficiency of transfer of orbital angular momentum to the rotation of the largest remnant depends on the degree of disruption. In the case of disruptive oblique impacts where the mass of the largest remnant is about half of the target mass, most of the orbital angular momentum is carried away by the escaping fragments and the efficiency becomes very low (<0.05), while the largest remnant acquires a significant amount of spin angular momentum in moderately disruptive impacts. These results suggest that collisions likely played an important role in rotational evolution of small asteroids, in addition to the recoil force of thermal re-radiation.  相似文献   

Transmission and reflection of planetary and topographic Rossby waves in a two-layer ocean     

Hiroshi Takeda 《Journal of Oceanography》1985,41(4):199-206

Transmission and reflection problems when kissing≓ occurs among planetary and topographic Rossby waves in a two-layer ocean are studied. The slope parameterS(=dh ₂/dx, whereh ₂is the thickness of the lower layer) is assumed to have constant values in the regionsx 0 andxL and to vary linearly with the increase ofx in the region0xL (refer to Fig. 2 in the text). Furthermore, a wave is entered fromx=– and kissing is assumed to occur in the region (0<)x _axx_b(<L).It is found that a wave of the same type as the incident wave is mainly transmitted when the width of the region in which kissing occurs,L _kiss(=tx _b–x_a), is smaller than _kiss=2/(¦K¦+ _y/2), whereK is a representative wavenumber in the regionx _ab, _y is they-component of , and is the frequency. WhenL _kiss is larger than _kiss, on the other hand, the main wave transmitted is of a different type to the incident wave. As an application, transmission and reflection problems of planetary Rossby waves are considered, and it is shown that when an external (internal) planetary Rossby wave is entered, an internal (external) one can be transmitted due to the effect of kissing.  相似文献   

Contents of strontinm-90 and ruthenium-106 in beach and shallow water deposits of noto peninsula     

Yoshikazu Yamamoto  Kikuo Takeda  Shunzo Ueda 《Journal of Oceanography》1976,32(2):83-88

⁹⁰Sr,¹⁰⁶Ru, natural strontium and major elements were studied in 12 samples of beach deposits from Togi, Fukuura and Shiga, and in 26 samples of shallow water sediments from sea off Fukuura, Noto Peninsula, Ishikawa Pref., Japan.The average contents of natural strontium and⁹⁰Sr in the beach deposits were 488 ppm ranging from 247 to 1,550 ppm and 45±9 pCi kg^–1-dry mud ranging from 18 to 72 pCi kg^–1-dry mud, respectively. While the average contents of natural strontium,⁹⁰Sr and¹⁰⁶Ru in the sediments were 234 ppm ranging from 136 to 415 ppm, 22±6 pCi kg^–1-dry sand ranging from 7 to 48 pCi kg^–1-dry sand and 0.6 ±0.2 nCi kg^–1-dry ranging from 0.3 to 1.2 nCi kg^–1-dry, respectively.The average contents of each natural strontium and⁹⁰Sr in the beach deposits were about two times higher than those in the shallow water sediments. But no obvious relation of natural strontium to⁹⁰Sr was found in all the samples. The enrichment of⁹⁰Sr and¹⁰⁸Ru in the beach deposits or tthe sediments were as high as 150320 and of 2,0003,000 compared with average contents of⁹⁰Sr and¹⁰⁶Ru in a liter of surface water from the Japan Sea. It is to be noticed that the average¹⁰⁶Ru to⁹⁰Sr ratio of 27 for the shallow water sediments is much higher than the average of 1.0 for surface sea water of the Japan Sea.As to major elements of the samples, the beach deposits are rich in silicon (Av. 70.89 ±0.92% SiO₂), but poor in iron (Av. 2.99±0.32% Fe₂O₃). Whereas the shallow water sediments are poor in silicon (Av. 52.96±10.33% SiO₂) and rich in iron (Av. 5.50±1.90% Fe₂O₃), calcium (Av. 9.64±9.22% CaO) and magnesium (Av. 2.83±1.58% MgO).  相似文献   

Topographically trapped waves over the continental shelf and slope     

Hiroshi Takeda 《Journal of Oceanography》1984,40(5):349-366

General characteristics of topographically trapped subinertia waves are discussed from the viewpoint of an eigenvalue problem and ray theory. Special attention is paid to the slope parameterS(x) (=(dh/dx)/h, wherex denotes the coordinate perpendicular to the shoreline, increasing seaward, andh(x) is the depth) which is a measure of the strength of the restoring force of the waves. Three cases for theS distribution are considered, in whichS is assumed to be positive at the coast and to tend to zero far from the coast. The first is whereS(x) decreases monotonically towards the open ocean. It is found in this case that waves are trapped near the coast. The second is whereS(x) does not decrease monotonically, but has a maximum. It is concluded that this case may contain two types of waves, i.e., those trapped near the coast and those trapped near the maximum, and the dispersion curves corresponding to different types may nearly intersect, namely, result in “kissing”. The third is whereS(x) has a negative region (corresponding to the presence of a trench). It is found in this case that an infinite sequence of waves is trapped in the negativeS region which propagate with the coast to their left (right) in the northern (southern) hemisphere besides the waves trapped near the coast. The topography in the second case corresponds to a typical continental shelf and a typical continental slope. It is shown by model calculation that trapped waves are present over the continental slope as well as over the continental shelf. Almost the same results are obtained for superinertia waves ifS is replaced by 1/h which is a measure of the restoring force of superinertia waves.  相似文献   

Chemical factors controlling the solubility of uraninite and their significance in the genesis of unconformity-related uranium deposits     

S. Kojima  S. Takeda  S. Kogita 《Mineralium Deposita》1994,29(4):353-360

A quantitative evaluation of the solubility of uraninite (UO₂) in aqueous solutions under hydrothermal conditions was made using previously reported thermodynamic data, so as to inquire into the controlling factors for Canadian unconformity-type ore mineralization as observed in the Athabasca uranium field. The results of solubility calculations suggest that uranyl carbonate complexes, such as UO₂CO ₃ ^o , UO₂(CO₃) ₂ ^2- and UO₂(CO₃) ₃ ^4- , predominate under relatively oxidizing and slightly acidic-alkaline conditions and that the uranyl chloride complex, UO₂Cl⁺ is dominant under acidic conditions. These features are predicted at temperatures up to 200 °C over reasonable ranges of CO₂ pressure (Pco₂) and salinity. Consequently, the physico-chemical parameters, such as oxygen activity (ao₂), and pH are regarded as the most important factors controlling uraninite solubility. Judging from the paragenetic sequences observed in most unconformity-type uranium deposits in the Athabasca district, appreciable decreases in the above variables are postulated to have occurred in the stage of principal uranium deposition. Such changes would be due to fluid-mixing phenomenon accompanied by the diagenetic-hydrothermal activity (Hoeve and Quirt 1987).  相似文献   

Configuration of subducting Philippine Sea plate and crustal structure in the central Japan region     

Takashi Iidaka  Tetsuya Takeda  Eiji Kurashimo  Tomonori Kawamura  Yoshiyuki Kaneda  Takaya Iwasaki 《Tectonophysics》2004,388(1-4):7

A seismic experiment with six explosive sources and 391 seismic stations was conducted in August 2001 in the central Japan region. The crustal velocity structure for the central part of Japan and configuration of the subducting Philippine Sea plate were revealed. A large lateral variation of the thickness of the sedimentary layer was observed, and the P-wave velocity values below the sedimentary layer obtained were 5.3–5.8 km/s. P-wave velocity values for the lower part of upper crust and lower crust were estimated to be 6.0–6.4 and 6.6–6.8 km/s, respectively. The reflected wave from the upper boundary of the subducting Philippine Sea plate was observed on the record sections of several shots. The configuration of the subducting Philippine Sea slab was revealed for depths of 20–35 km. The dip angle of the Philippine Sea plate was estimated to be 26° for a depth range of about 20–26 km. Below this depth, the upper boundary of the subducting Philippine Sea plate is distorted over a depth range of 26–33 km. A large variation of the reflected-wave amplitude with depth along the subducting plate was observed. At a depth of about 20–26 km, the amplitude of the reflected wave is not large, and is explained by the reflected wave at the upper boundary of the subducting oceanic crust. However, the reflected wave from reflection points deeper than 26 km showed a large amplitude that cannot be explained by several reliable velocity models. Some unique seismic structures have to be considered to explain the observed data. Such unique structures will provide important information to know the mechanism of inter-plate earthquakes.  相似文献   

Verification of two-dimensional non-linear analysis of sand-structure system by examining the results of the shaking-table test     

Akira Ohtsuki  Masanori Hirota  Kikuo Ishimura  Kazutomo Yokoyama  Kiyoshi Fukutake 《地震工程与结构动力学》1992,21(7):591-607

The verification of a two-dimensional non-linear analysis based on a hybrid constitutive model, which consists of the Ramberg-Osgood model extended to two-dimensional problems and a dilatancy model, is discussed through a comparison of the shaking-table test results for a one-storey structure standing on a dry sandy deposit with those for the same on a saturated sandy deposit. Since the relationships G vs. γ and h vs. γ for shear strains of 10^?5?10^?3 can be obtained accurately by an inversion analysis of the resonance curve of the sandy deposit the proposed non-linear method can represent well the observed non-linear response of the dry or the saturated sandy deposit including the structure. This method, however, should be applied carefully to assess the response of a soil-structure system when the three-dimensional interaction affects significantly the response of the model. An equivalent linear analysis using a sway-rocking model is applied to simulate the non-linear ground motion including the three-dimensional interaction, and it is found that the sway-rocking model can also represent well the non-linear response of the system.  相似文献   

Stress induced transformation of pigeonites from achondritic meteorites     

Hiroshi Mori  Hiroshi Takeda 《Physics and Chemistry of Minerals》1988,15(3):252-259

A transmission electron microscopic (TEM) study was conducted to investigate the stress-induced transformation mechanisms of pigeonites from two achondrites. In pigeonites from the Allan Hills 77257 ureilite, abundant lamellae of orthopyroxene-pigeonite intergrowth accompanied by minor amounts of blebby augite precipitates were observed. In pigeonites from the Juvinas eucrite, some stacking faults running through the (001) augite lamellae were observed although most of the stacking faults terminated at the host-lamella interface. High resolution TEM observation shows the fringe offset produced by the stacking fault in the Juvinas pigeonites. The magnitude of the mismatch parallel to [001] is approximately c/4, which is related to the formation of the partial edge dislocation near the host-lamella interface. The partial dislocation is imaged as an edge dislocation with an (002) extra-plane. Three partial dislocation mechanisms with distinct displacement vectors are proposed in order to explain the stress-induced transformation textures observed in the achondritic pyroxenes. Further study will be required to determine unequivocally the mechanism of atomic displacements during stress-induced transformation. However, regardless of the actual mechanism of transformation, it is not difficult to convert orthopyroxene to clinopyroxene or vice versa by this transformation from the structural point of view. Low-Ca pyroxenes are deformed without a stress-induced transformation by slip at high temperature and geologically reasonable strain rates. However, meteoritic pyroxenes can be deformed by stress-induced transformation even at high temperature because preterrestrial impact processes will produce a deformation condition with high strain rates. Deformation at high strain rates and high temperature is very important when we interpret the microtexture of meteoritic pyroxenes.  相似文献   

Impact of climate change on the Hii River basin and salinity in Lake Shinji: a case study using the SWAT model and a regression curve     

H. Somura  J. Arnold  D. Hoffman  I. Takeda  Y. Mori  M. Di Luzio 《水文研究》2009,23(13):1887-1900

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