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排序方式: 共有74条查询结果,搜索用时 31 毫秒
1.
A model calculation to predict infrared Shuttle flow due to the radiative relaxation of vibration of the NO molecule is presented. Space Shuttles hit atmospheric NO molecules at a very high speed (≈ 8 km s?1) and excite vibrational and rotational motions up to the temperature of 54,000 K. With the electric dipole radiation of Δν = 1, 2, 3, and particularly 4 (ν is the vibrational quantum number), the excited NO molecules emit infrared radiation before they collide with other molecules. The total radiation power is estimated to be 170AμW, where A is the cross-section area of the Shuttle in m2 if no adsorption of the NO molecule takes place on the Shuttle surface. The intensity of each infrared line is calculated as a function of time, including all vibrational states up to ν = 35. For example, the 5039 cm?1 line (ν = 24 → 20) has a maximum intensity of about 2.3 × 10?21 W molecule at around 0.2 ms, which corresponds to 80 cm from the Shuttle surface if the recoil speed of the molecules is 4 km s?1. 相似文献
2.
Photographic observations were carried out at depths of the shelf edge at the mouth of Uchiura Inlet, Suruga Bay, central Japan in order to clarify the life style of the isocrinid stalked crinoid,Metacrinus rotundus (Echinodermata). The distribution of the species was found to be restricted to a narrow area where boulders and rock outcrops were locally present. Mean density of the crinoid was 0.05 m–2, and this value was an order of magnitude smaller than that of the deeper isocrinid,Diplocrinus wyvillethomsoni, reported from the Bay of Biscay.Metacrinus rotundus formed a parabolic filtration fan with its arms recurved into the bottom current, and was thought to be a passive suspension feeder elevating the fan into the water column by its stalk. The distal half of the stalk lay along the hard substratum and about ten groups of cirri grasped the substratum. This mode of attachment was similar to that ofCenocrinus rather than that ofDiplocrinus. Metacrinus rotundus collect food at the layer between 10 and 50 cm above the sea floor, and do not utilize a higher layer even when this layer could be utilized by climbing over a larger boulder. Resuspended benthic materials are thought to be important as a food source forM. rotundus, and the crinoids seek not only locations of stronger currents but also the position where much resuspended matter is available. 相似文献
3.
Momentum and heat flux were measured with a sonic anemometer at the Marine Observation Tower in the port of ItÔ. Under unstable conditions (T
w
-T
a
=3C4C), using the eddy correlation method, results show thatCd=(1.2±0.3)×10–3 andCh=(1.5±0.3)×10–3 at 5.5 m above mean sea level except for the case of weak winds.An unexpected relationship betweenCd and (–z/L) was observed, that is,Cd decreases as (–z/L) increases. If roughness variation over the sea is taken into account, we can explain the decrease in the range of (–z/L) less than 1, but not in the range greater than 1. This is due to a strong instability effect and the change of roughness class, from moderately rough to smooth. 相似文献
4.
Koichiro Fujinaga Tatsuo Nozaki Takazumi Nishiuchi Kiyoko Kuwahara Asuhiro Kato 《Resource Geology》2006,56(4):399-414
Abstract. Major and trace element contents are reported for Permian manganese ore and associated greenstone from the Ananai manganese deposit in the Northern Chichibu Belt, central Shikoku, Japan. The manganese deposit occurs between greenstone and red chert, or among red chert beds. Chemical compositions of manganese ore are characterized by enrichments in Mn, Ca, P, Co, Ni, Zn, Sr and Ba, and negative Ce and positive Eu anomalies relative to post-Archean average Australian Shale (PAAS). Geochemical features of the manganese ore are similar to those of modern submarine hydrother-mal manganese deposits from volcanic arc or hotspot setting. In addition, geochemical characteristics of the greenstone closely associated with the Ananai manganese deposit are analogous to those of with-in plate alkaline basalt (WPA). Consequently, the Ananai manganese deposit was most likely formed by hydrothermal activity related to hotspot volcanism in the Panthalassa Ocean during the Middle Permian. This is the first report documenting the terrestrially-exposed manganese deposit that was a submarine precipitate at hotspot. 相似文献
5.
Rare Earth, Major and Trace Elements in the Kunimiyama Ferromanganese Deposit in the Northern Chichibu Belt, Central Shikoku, Japan 总被引:1,自引:0,他引:1
Yasuhiro Kato Koichiro Fujinaga Tatsuo Nozaki Kentaro Nakamura Ryuji Ono Hiroshi Osawa 《Resource Geology》2005,55(4):291-300
Abstract. Rare earth, major and trace element geochemistry is reported for the Kunimiyama stratiform ferromanganese deposit in the Northern Chichibu Belt, central Shikoku, Japan. The deposit immediately overlies greenstones of mid-ocean ridge basalt (MORB) origin and underlies red chert. The ferromanganese ores exhibit remarkable enrichments in Fe, Mn, P, V, Co, Ni, Zn, Y and rare earth elements (excepting Ce) relative to continental crustal abundance. These enriched elements/ Fe ratios and Post-Archean Average Australian Shale-normalized REE patterns of the ferromanganese ores are generally analogous to those of modern hydrothermal ferromanganese plume fall-out precipitates deposited on MOR flanks. However in more detail, Mn and Ti enrichments in the ferromanganese ores are more striking than the modern counterpart, suggesting a significant contribution of hydrogenetic component in the Kunimiyama ores. Our results are consistent with the interpretation that the Kunimiyama ores were umber deposits that primarily formed by hydrothermal plume fall-out precipitation in the Panthalassa Ocean during the Early Permian and then accreted onto the proto-Japanese island arc during the Middle Jurassic. The presence of strong negative Ce anomaly in the Kunimiyama ores may indicate that the Early Permian Panthalassa seawater had a more striking negative Ce anomaly due to a more oxidizing oceanic condition than today. 相似文献
6.
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
7.
By coupling FEM and BEM, a numerical method was developed for dynamic response analyses of dam–foundation–reservoir systems in the time domain. During formulation, the weighted residual procedure was applied to the coupling of several equations of motion for solid and fluid in the FE and BE regions, and an algorithm similar to the Newmark beta procedure was finally obtained. The algorithm is advantageous in that it takes into account all the effects of dam–foundation, dam–reservoir and reservoir–foundation interactions, as well as of the absorption of both elastodynamic and hydrodynamic waves at the boundaries of the foundation and the reservoir. To demonstrate the validity of the present method, the impulsive response of a dam–foundation–reservoir system was calculated using the algorithm, and showed a good agreement with the existing results obtained by other researchers. 相似文献
8.
The structure of the cosmic ray electron halo of a starburst galaxy depends strongly on the nature of galactic wind and the
configuration of the magnetic field. We have investigated these dependencies by solving numerically the propagation of electrons
originating in starburst galaxies, most likely in supernova remnants. The calculations are made for several models for the
galactic winds and for the configuration of the magnetic fields for comparison with observations. Our simulation of a quasi-radio
halo reproduces both the extended structure of ∼9 kpc and the subtle hollow structure near the polar region of the radio halo
that are observed in the starburst galaxy NGC 253. These findings suggest the existence of strong galactic wind in NGC 253.
相似文献
9.
Besshi-type Cu deposits are strata-bound volcanogenic massive sulfide deposits usually associated with mafic volcanic rocks or their metamorphic equivalents. Although there are numerous Besshi-type deposits in the Sanbagawa metamorphic belt, Japan, their tectonic settings and depositional environments remain controversial because of a lack of depositional age constraints. We report Re-Os data for the Iimori deposit, one of the largest Besshi-type deposits in western Kii Peninsula, in order to examine the robustness of the Re-Os isotope system for dating sulfide minerals in the high-P/T metamorphic belt and to elucidate the primary depositional environment of the Iimori sulfide ores. An 11-point Re-Os isochron plot yields an age of 156.8 ± 3.6 Ma. As this Re-Os isochron age is significantly older than the timing of the Sanbagawa peak metamorphism (110-120 or ∼90 Ma) and a well-defined isochron was obtained, the Re-Os age determined here is most likely the primary depositional age. Despite high-grade metamorphism at up to 520 ± 25 °C and 8-9.5 kbar, the Re-Os isotope system of the Iimori sulfides was not disturbed. Hence, we consider that the whole-rock Re-Os closure temperature for the Iimori sulfide ores was probably higher than 500 °C. As the accretion age of the Sanbagawa metamorphic belt is considered to be 120-130 or 65-90 Ma on the basis of radiolarian and radiometric ages, we estimated the time from the Iimori sulfide deposition on the paleo-seafloor to its accretion at the convergent plate boundary to be greater than 25 Myr. Consequently, the depositional environment of the Iimori sulfide ores was not in the marginal sea, but was truly pelagic. 相似文献
10.
Masanori Iye Tatsuo Ueda Masafumi Noguchi Shinko Aoki 《Astrophysics and Space Science》1983,89(2):363-376
A new scheme has been devised to calculate discrete unstable global shearing spiral modes of gaseous disk models of galaxies. The scheme makes use of the Legendre expansion of eigen functions and the problem of stability analysis is reduced to an eigenvalue problem of an infinite matrix. The spiral patterns of these shearing wave solutions of linearized equations change their form in the course of time due to the differential rotation of the equilibrium disk. These shearing wave solutions are presumed to have intermediate characteristics between so-called density-waves and material arms. Comparison between these shearing modes and the non-shearing normal modes for a series of disk models is presented. 相似文献