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1.
J. Rajchl J. Bočcek D. Očenáš J. Škvarka P. Zimnikoval H. Murayama K. Ohtsuka 《Earth, Moon, and Planets》1995,68(1-3):479-486
Some results following from two contemporary photographical programs (Slovakia and Japan) for persistent meteor train spectra are compared. It shows that even though both programs are not too different according to their lenses and films used, the spectral interval detected is very different. In this respect prism as a dispersion element is more favourable than the grating with blaze wavelength near 610 nm. However, some results previously assumed as typicai for presented persistent trains-e.g. the forbidden Herzberg O2 emission, the NO2 continuum and OH red emissions-seem to be substanciated especially due to higher and linear dispersion of those grating spectra. 相似文献
2.
Sea‐surface temperature and salinity changes in the northwest Pacific since the Last Glacial Maximum
The oxygen isotope records of both benthic and planktonic Foraminifera in five piston cores, collected from the region between the Oyashio and Kuroshio Currents near Japan, clearly show the marked latitudinal shifts of these two currents during the past 25 kyr. Under the present hydrographic condition, a clear relationship between the sea‐surface temperature (SST) and oxygen isotope differences from benthic to planktonic Foraminifera is observed in this region. Using this relationship, we find decreased SSTs of 12–13°C (maximum 15°C) in the southernmost core site at the Last Glacial Maximum (LGM), indicating the Oyashio Current shifted southward. The SSTs at the southern two core sites abruptly increased more than 10°C at 10–11 ka, suggesting the Kuroshio Current shifted northward over these sites at 10–11 ka. In contrast, the northern two core sites have remained under the influence of the cold Oyashio Current for the past 25 kyr. With the reasonable estimate of bottom‐water temperature decrease of 2.5°C at the LGM, the SSTs estimated by this new method give exactly the same SST values calculated from Mg/Ca ratio of planktonic Foraminifera, allowing palaeosea‐surface salinities to be reconstructed. The result suggests that the ice volume effect was 1.0 ± 0.1‰ at the LGM. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
3.
Naomi AOTA Yutaka MIYAMOTO Sakae KOSANDA Yasuji OURA Koh SAKAMOTO 《Geostandards and Geoanalytical Research》1994,18(1):65-84
Fifteen rock reference samples "Igneous rock series" issued by the Geological Survey of Japan were analysed for up to 31 elements by neutron activation analysis (NAA); 14 MeV-NAA for Si and Al, fission track method for U, radiochemical and instrumental NAA for rare-earth elements, and instrumental NAA for the remaining elements, with reactor neutrons for the latter three. The present results are compared with published values. 相似文献
4.
This paper discusses the situation of sea navigation in south East Asia focusing on the Strait of Malacca. The strait links
the Indian and Pacific oceans, which is considered one of the busiest in several narrow channels around the world. The paper
highlights the significance of the strait to global maritime trade, volume of traffic, and rising environmental and social
consequences in the strait. A feasibility study of constructing a new shipping canal in the South Thai Kra Isthmus as an alternative
option of Malacca route had been studied since 19th century. The paper explores suitable sites for a potential shipping canal
in the Kra Isthmus using physiographic spatial data i.e., elevation, sea charts, geology, soils and river systems. Each spatial
data was considered as a separate decision variable for site evaluation. Separate evaluation criterions were prepared for
each variable based on shipping canal requirements. Overlaying the maps in GIS environment, the variables were carefully evaluated,
and five geographic sites for the canal were derived. The length of the shipping canal over sea and land was computed for
each site. Site B located in south of Ranong and Chumphon provinces, was the shortest one, whereas site C in Surat Thani,
Pangnna and Krabi provinces was the longest. However, each site consisted of benefits and constraints. 相似文献
5.
6.
Shinsuke Abe Noboru Ebizuka Hideyuki Murayama Katsuhito Ohtsuka Satoru Sugimoto Masa-yuki Yamamoto Hajime Yano Jun-ichi Watanabe Jiří Borovička 《Earth, Moon, and Planets》2004,95(1-4):265-277
Spectra of persistent meteor trains were observed at wavelength between 300 and 930 nm. Two obtained train spectra during
the 1998 and 2001 Leonid meteor showers are reported here. During the 1998 Leonids, one train was detected by a photographic
camera with a spectrograph covering 370–640 nm region. On the other hand, during the 2001 Leonids, video observations were
carried out using image intensified cameras in ultraviolet (UV), visible and near infrared (near-IR) wavelengths. Temperatures
in persistent trains have been measured by atmospheric O2 A(0,1) band at the wavelength near 864.5 nm. From a video spectrum obtained just 7 s after parent fireball’s flare, a rotational
temperature of 250 K at altitude of 88.0±0.5 km was estimated. We can say that the cooling time scale of train strongly depends
on the initial mass of its fireball at least for Leonids. Based on cooling constant calculated from our results, we estimated
a temperature of ∼
∼130 K as a final exothermic temperature at early stage of persistent trains. 相似文献
7.
In April 1969, the chondrite was accidentally found in the side wall of the vegetable storage excavated at Shibayama-machi, Sanbu-gun, Chiba-ken, Japan, by Mr. A. Ishii and his grandson, Mr. S. Ito. The chondrite named Shibayama has been weathered thoroughly for a long period of burial underground. The bulk chemical composition, especially total Fe (21.41%) and ratios of Fetotal/SiO2(0.557), SiO2/MgO (1.59) and molar composition of olivine (Fa23) and pyroxene (Fs22) as well as mineral composition, indicate that Shibayama is a typical olivine-hypersthene chondrite. If the oxidized Fe is assumed only from metallic Fe, the original metallic Fe (7.75%) and Femetal/Fetotal(0.361) also support the above conclusion. From the well-recrystallized texture, indistinct and obliterated chondrule-matrix boundary, homogeneous composition of olivine and pyroxene, absence of igneous glass, and interstitial and well-developed plagioclase, this chondrite could be classified in petrologic type 6. Mosaic texture, kink bands, undulatory extinction of silicate grains and maskelynitization of plagioclase indicate that Shibayama suffered from a heavy shock effect, as is seen in other L-6 group chondrites. 相似文献
8.
Effects of solar wind parameters on the development of substorms during the events of southward interplanetary magnetic field (IMF) lasting more than one hour were studied. Analysis on 175 events with average magnitude of the southward component of IMF larger than l·5γ as observed in July–December 1965 lead to the following results: (1) The total auroral electrojet (AEJ) current associated with the southward IMF event is approximately proportional to the time integral of the magnitude of the southward component. (2) The azimuthal component of IMF also affects the AEJ development. AEJ about twice as intense were observed when IMF was directed duskward than when IMF was directed dawnward. (3) AEJ intensity is strongly affected by the solar wind velocity during the southward IMF events, the intensity being approximately proportional to the square of the velocity. (4) No indication was found that the angle between the Sun-Earth line and the Earth's dipole axis plays any role on the development of substorms if effects of the solar wind parameters as described above are eliminated. 相似文献
9.
Norihiro Murayama Kou Arimura Nobuaki Okajima Junji Shibata 《International Journal of Mineral Processing》2009,93(2):110-114
The hydrothermal synthesis of AlPO4-n which is a functional material of aluminophosphate, was conducted from two kinds of aluminum dross discharged in an aluminum regeneration factory. The effect of structure-directing agent (SDA) on the formation behavior of AlPO4-n from aluminum dross, the suitable condition to obtain AlPO4-n efficiently, and the pore structure and gas adsorption property were investigated in this study.AlPO4-5 and AlPO4-34 are mainly formed from aluminum dross as a raw material, and it is possible to make AlPO4-5 successfully as a main product by adjusting the amount of triethylamine (TEA) as SDA. The gas adsorption amount with AlPO4-5 is the following order; ammonia > dipropylamine > benzene, and it is found that this order mainly corresponds with the polarity of molecule among them. 相似文献
10.
The rapid growth of urban space and its environmental challenges require precise mapping techniques to represent complex earth surface features more accurately. In this study, we examined four mapping approaches (unsupervised, supervised, fuzzy supervised and GIS post-processing) using Advanced Land Observing Satellite images to predict urban land use and land cover of Tsukuba city in Japan. Intensive fieldwork was conducted to collect ground truth data. A random stratified sampling method was chosen to generate geographic reference data for each map to assess the accuracy. The accuracies of the maps were measured, producing error matrices and Kappa indices. The GIS post-processing approach proposed in this research improved the mapping results, showing the highest overall accuracy of 89.33% as compared to other approaches. The fuzzy supervised approach yielded a better accuracy (87.67%) than the supervised and unsupervised approaches. The fuzzy supervised approach effectively dealt with the heterogeneous surface features in residential areas. This paper presents the strengths of the mapping approaches and the potentials of the sensor for mapping urban areas, which may help urban planners monitor and interpret complex urban characteristics. 相似文献