Solar radio burst (type III)     

Hari Om Vats  M. R. Deshpande  K. N. Iyer  Tetsuro Kondo  Takeshi Isobe 《Astrophysics and Space Science》1996,243(1):251-254

This article describes the observations of a type III radio burst observed at 103 MHz simultaneously by the two radio telescopes situated at Rajkot (22.3°N, 70.7°E) and Thaltej (23°N, 72.4°E). This event occurred on September 30, 1993 at about 0430 UT and lasted for only half a minute. The event consisted of several sharp spikes in a group. The rise and fall time of these are comparable, however the peaks of individual spikes varied by a factor of four. The comparison of these observations with the data of solar radio spectrograph HiRAS indicates that this was a metric radio burst giving highest emission at about 103 MHz.  相似文献   

Ecologic and taxonomic diversification in the Mesozoic brackish-water bivalve faunas in Japan, with emphasis on infaunalization of heterodonts     

Yasuo Kondo  Takeshi Kozai  Naoki Kikuchi  Kazuhiro Sugawara 《Gondwana Research》2006,10(3-4):316-327

Mesozoic brackish-water bivalve faunas in Japan diversified in three steps: at the beginning of the Early Jurassic, Early and Late Cretaceous. The Hettangian Niranohama Fauna in northeastern Honshu represents the establishment of a heterodont-dominated brackish-water fauna that persisted until the early Late Cretaceous. No similar composition is known from the Triassic. The infauna consists mostly of non-siphonate and some short-siphonate heterodonts, while the epifauna is represented by diverse pteriomorphian families. In the Early Cretaceous Tetori Group in central Honshu, the long-siphonate heterodonts Tetoria (Corbiculidae) and the semi-infaunal soft-bottom oyster Crassostrea appeared. The evolutionary diversification of the latter, known as the most important element of modern brackish-water faunas, may thus originate at that time. In the early Late Cretaceous (Cenomanian) of the Goshoura and Mifune Groups in west Kyushu, several euryhaline deep-burrowing heterodont families, such as Veneridae and Tellinidae, further diversified in the brackish and marine environments. The Late Cretaceous is characterized by massive shell biolithic beds in which large Crassostrea species are common, a feature common for Cenozoic brackish-water faunas. The long-term changes in the composition of the brackish-water faunas in Japan represents thus an evolutionary record, irrespective of the severe physiological and environmental conditions imposed on the highly conservative nature of the fauna.  相似文献   

Biogenic Silica Record in Lake Biwa of Central Japan over the Past 145,000 Years   总被引：2，自引：0，他引：2  

Jule Xiao  Yoshio Inouchi  Hisao Kumai  Shusaku Yoshikawa  Yoichi Kondo  Tungsheng Liu  Zhisheng An 《Quaternary Research》1997,47(3):277-283

The record of the biogenic silica flux (BSF, g cm⁻²(10³yr)⁻¹) in Lake Biwa reflects changes in diatom productivity in the lake and provides information regarding changes in paleoclimatic conditions. The BSF record of Lake Biwa demonstrates five periods over the past ca. 145,000 yr when the BSF values were significantly greater than 7.5 g cm⁻²(10³yr)⁻¹, and five intervals when they were lower. The data imply that paleoclimatic conditions were warmer and wetter from ca. 123,000 to 115,000, 103,000 to 95,000, 88,000 to 72,000, 57,000 to 32,000 yr B.P., and around ca. 6000 yr B.P. when the BSF values were greater, and relatively dry and cold from ca. 141,000 to 123,000 yr B.P. and during intervals between two of the five warm and wet episodes when the BSF values were lower. Time series of the BSF record can be correlated with the record of biogenic silica content in Lake Baikal and the marine oxygen isotope stages 1 through 6. Furthermore, the BSF values varied with much higher amplitude during the last interglaciation than during the last glaciation, probably implying that the diatom productivity in Lake Biwa was likewise more variable and had a larger range under interglacial conditions than under glacial conditions.  相似文献   

Macroscopic criteria for Green type porous materials with spheroidal voids: application to double porous materials          下载免费PDF全文

W. Q. Shen  J.‐F. Shao  D. Kondo 《国际地质力学数值与分析法杂志》2017,41(13):1453-1473

Combined effects of matrix plastic compressibility and void shape are investigated for ductile porous materials. To this end, a spheroidal volume containing a confocal spheroidal (prolate or oblate) void subjected to uniform strain rate boundary conditions has been first studied. A Green type matrix is chosen as a prototype for investigating effects of plastic compressibility. This is carried out by using a kinematics limit analysis theory from which a closed‐form expression of the macroscopic criterion is established for the considered class of materials. These results are then extended to ductile porous materials made up of a green matrix containing randomly oriented spheroidal voids. In the framework of a two‐step homogenization procedure, the obtained results are implemented to describe the macroscopic behavior of double porous materials involving spherical voids at the microscale and randomly oriented and distributed spheroidal voids at the mesoscale. For validation purpose, the new derived criteria are assessed and validated by comparing their predictions to available upper bounds and numerical data from literature. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Elastoplastic damage modeling of desaturation and resaturation in argillites     

Y. Jia  H. B. Bian  K. Su  D. Kondo  J. F. Shao 《国际地质力学数值与分析法杂志》2010,34(2):187-220

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Nitric oxide profiles measured in situ during the Globus '85 campaign     

W. A. Matthews  Y. Kondo  P. Fabian  B. C. Krüger 《Journal of Atmospheric Chemistry》1989,8(3):229-240

Nitric oxide profiles obtained from three flights of chemiluminescent instruments during the Globus '85 campaign held in France in the autumn of 1985 are reported. When the profile obtained in the early morning of 20 September is compared with the flight made the previous afternoon, an average morning to midday NO ratio of 0.7 for the region between 26 and 33 km is obtained. This value is in good agreement with theoretical studies involving the photolysis of N₂O₅ and the establishment of the NO₂–NO equilibrium.  相似文献   

Intercomparison of NO column measurements during MAP/GLOBUS 1985     

R. L. McKenzie  W. A. Matthews  Y. Kondo  R. Zander  Ph. Demoulin  P. Fabian  D. G. Murcray  F. J. Murcray  O. Lado-Bordowsky  C. Camy-Peyret  H. K. Roscoe  J. A. Pyle  R. D. McPeters 《Journal of Atmospheric Chemistry》1988,7(4):353-367

Column measurements of nitric oxide were made using several techniques during the MAP/GLOBUS campaign in France in September 1985. The data sets are nearly co-located and simultaneous, therefore allowing a valid intercomparison of the various measurement methods. The range of altitudes sampled differs from instrument to instrument. This complicates the comparison because the data sets are to some extent complementary. The NO distributions apparently vary significantly from day to day, and possibly over shorter timescales. Changes in dynamics may be responsible for these variations. The results from the instruments which measure in the infrared and the ultraviolet are self-consistent, and show good agreement with photochemical predictions. On 19 September, when the intercomparison was made, the profile measured by the in-situ chemiluminescent instrument differed significantly from the predicted profile, and the measured columns were generally higher.  相似文献   

A simple model of drainage flow in a valley     

Takeshi Sato  Junsei Kondo 《Boundary-Layer Meteorology》1988,45(4):355-369

A model of the drainage flow in a valley under calm conditions has been developed on the basis of the conservation laws of mass, momentum, and heat. The inflow of mass and heat from side-slopes is incorporated, and the momentum and sensible heat exchanges between valley drainage flow and valley floor are parameterized.The characteristic velocity of valley drainage flow is expressed in terms of the following parameters: three potential temperature differences representing the temperature field in the valey; topographic parameters of the valley; mean bulk coefficients representing the aerodynamic conditions of the valley floor; and the stability of the ambient atmosphere. The characteristic thickness includes additional parameters of side-slope flow.That the model satisfactorily predicts the characteristic thickness and velocity is shown from comparison with observations from valleys several hundred meters to a few hundred kilometers long.  相似文献   

Aerodynamic roughness over an inhomogeneous ground surface   总被引：4，自引：0，他引：4  

Junsei Kondo  Hiromi Yamazawa 《Boundary-Layer Meteorology》1986,35(4):331-348

The aerodynamic roughness parameter z ₀ over inhomogeneous ground surfaces, such as cities, rural towns and so on, is determined by analyzing the wind data at AMeDAS observatories in the Tohoku and Kanto districts of Japan, by making use of Rossby number similarity theory. It is found that the aerodynamic roughness parameter is proportional to the average size of the roughness elements.A practical method of estimating the aerodynamic roughness parameter over an extensive area with various inhomogeneities is developed. In this method, the Digital National Land Information data bank is employed. As an example, the roughness parameter distribution around Tsukuba Academic City is presented.  相似文献   

The effect of the Mt St Helens eruption on tropospheric and stratospheric ions   总被引：1，自引：0，他引：1  

Y. Kondo  R. Reiter  H. Jäger  M. Takagi 《Pure and Applied Geophysics》1982,120(1):11-17

Balloon-borne observations of electrical conductivity in the troposphere and stratosphere were performed using conductivity sondes at Garmisch-Partenkirchen, West Germany, from June to November, 1980, after the Mt St Helens eruption. A significant decrease of atmospheric ions in the altitudes from the troposphere to lower stratosphere has been detected until several months after the eruption in comparison with the observational results obtained before the eruption. Simulteneous ruby lidar observation a month after the eruption indicates an increased amount of aerosol at nearly the same altitude as that of conductivity decrease. Several months after the eruption it appears that aerosols detected by lidar and those effective in reducing ion concentration have different profiles.  相似文献