全文获取类型
收费全文 | 60篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 2篇 |
大气科学 | 3篇 |
地球物理 | 17篇 |
地质学 | 22篇 |
海洋学 | 10篇 |
天文学 | 4篇 |
综合类 | 2篇 |
自然地理 | 5篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 7篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1989年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有65条查询结果,搜索用时 140 毫秒
41.
Narumi Takahashi Yasuhisa Ishihara Hiroshi Ochi Tatsuya Fukuda Jun’ichiro Tahara Yosaku Maeda Motoyuki Kido Yusaku Ohta Katsuhiko Mutoh Gosei Hashimoto Satoshi Kogure Yoshiyuki Kaneda 《Marine Geophysical Researches》2014,35(3):243-253
We have developed a new system for real-time observation of tsunamis and crustal deformation using a seafloor pressure sensor, an array of seafloor transponders and a Precise Point Positioning (PPP ) system on a buoy. The seafloor pressure sensor and the PPP system detect tsunamis, and the pressure sensor and the transponder array measure crustal deformation. The system is designed to be capable of detecting tsunami and vertical crustal deformation of ±8 m with a resolution of less than 5 mm. A noteworthy innovation in our system is its resistance to disturbance by strong ocean currents. Seismogenic zones near Japan lie in areas of strong currents like the Kuroshio, which reaches speeds of approximately 5.5 kt (2.8 m/s) around the Nankai Trough. Our techniques include slack mooring and new acoustic transmission methods using double pulses for sending tsunami data. The slack ratio can be specified for the environment of the deployment location. We can adjust slack ratios, rope lengths, anchor weights and buoy sizes to control the ability of the buoy system to maintain freeboard. The measured pressure data is converted to time difference of a double pulse and this simple method is effective to save battery to transmit data. The time difference of the double pulse has error due to move of the buoy and fluctuation of the seawater environment. We set a wire-end station 1,000 m beneath the buoy to minimize the error. The crustal deformation data is measured by acoustic ranging between the buoy and six transponders on the seafloor. All pressure and crustal deformation data are sent to land station in real-time using iridium communication. 相似文献
42.
Kazue Tazaki Ryuji Asada Zara Gerhardt Lindenmayer Tatsuya Shirotori Juliana Missiaggia Vargas Carlos Henrique Nowatzki Osmar Wöhl Coelho 《International Journal of Earth Sciences》2009,98(1):227-238
Rock erosion is attracting increasing attention from scientists worldwide. The area encompassing the Saint John Baptist Church,
Saint John Village, XVII century ruins in Rio Grande do Sul at the UNESCO World Heritage Site is considered a Brazilian treasure.
However, the risk of damage to this site from rock erosion has recently increased tremendously. Generally, the rocky construction
such as fence, wall and tomb stone, seems strong but is actually extremely sensitive to erosion caused by lichens, fungi,
molds and bacteria. Because of biological erosion and massive exposure, the fresh rock is dominated by clays and microorganisms.
Water-adsorbing clays and microorganisms influence the mechanisms of the rock erosion. In this study, the formation of bio-clay-minerals
in porous structure of pisolite was demonstrated using electron microscopy. Bacterial clay mineralization can deform the rock
structure and even produce organic materials. Biological activity could easily corrode rocky constructions around the Saint
John Baptist Church site. The rocks are pisolitic laterites possibly formed in Tertiary over the Kretaceous Parana flood Basalts.
Samples inhabited by lichens and fungi were collected from a collapsed wall in the ancient church. The zonal reddish-brown
pisolites are 4 mm in diameter in a matrix of clays associated with porous and empty spaces. Elemental distribution maps from
X-ray fluorescence microscopy show iron-rich spherules of pisolite, whereas the matrix is composed of Al, Si, Mn, and Sr;
thus producing goethite and kaolinite. Transmission electron microscopic observation showed that various types of bacteria
inhabit the spherule and are associated with clay minerals and graphite. STEM elemental analysis confirmed the bio-clay-mineralization
with Al, Si, S, and Fe, around bacterial cells. The results presented here will improve our understanding of nm-scale bio-mineralization
and bio-erosion in lateritic rocks.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
43.
The relative proportions of asteroidal and cometary materials in the zodiacal cloud is an ongoing debate. The determination of the asteroidal component is constrained through the study of the Solar System dust bands (the fine-structure component superimposed on the broad background cloud), since they have been confidently linked to specific, young, asteroid families in the main belt. The disruptions that produce these families also result in the injection of dust into the cloud and thus hold the key to determining at least a minimum value for the asteroidal contribution to the zodiacal cloud. There are currently known to be at least three dust band pairs, one at approximately 9.35° associated with the Veritas family and two central band pairs near the ecliptic, one of which is associated with the Karin subcluster of the Koronis family. Through careful co-adding of almost all the pole-to-pole intensity scans in the mid-infrared wavebands of the Infrared Astronomical Satellite (IRAS) data set, we find strong evidence for a partial Solar System dust band, that is, a very young dust band in the process of formation, at approximately 17° latitude. We think this is a confirmation of the M/N partial band pair first suggested by Sykes [1988. IRAS observations of extended zodiacal structures. Astrophys. J. 334, L55-L58]. The new dust band appears at some but not all ecliptic longitudes, as expected for a young, partially formed dust band. We present preliminary modeling of the new, partial dust band which allows us to put constraints on the age of the disruption event, the inclination and node of the parent body at the time of disruption, and the quantity of dust injected into the zodiacal cloud. 相似文献
44.
In order to clarify Al2O3 content and phase stability of aluminous CaSiO3-perovskite, high-pressure and high-temperature transformations of Ca3Al2Si3O12 garnet (grossular) were studied using a MA8-type high-pressure apparatus combined with synchrotron radiation. Recovered samples
were examined by analytical transmission electron microscopy. At pressures of 23–25 GPa and temperatures of 1000–1600 K, grossular
garnet decomposed into a mixture of aluminum-bearing Ca-perovskite and corundum, although a metastable perovskite with grossular
composition was formed when the heating duration was not long enough at 1000 K. On release of pressure, this aluminum-bearing
CaSiO3-perovskite transformed to the “LiNbO3-type phase” and/or amorphous phase depending on its Al2O3 content. The structure of this LiNbO3-type phase is very similar to that of LiNbO3 but is not identical. CaSiO3-perovskite with 8 to 25 mol% Al2O3 was quenched to alternating lamellae of amorphous layer and LiNbO3-type phase. On the other hand, a quenched product from CaSiO3-perovskite with less than 6 mol% consisted only of amorphous phase. Most of the inconsistencies amongst previous studies
could be explained by the formation of perovskite with grossular composition, amorphous phase, and the LiNbO3-type phase.
Received: 11 April 2001 / Accepted: 5 July 2002 相似文献
45.
46.
Naveen Hakhoo Bindra Thusu Devleena Mani Ghulam M. Bhat Jonathan Craig Juergen Thurow Mateen Hafiz Sudeep Kanungo Sumita Koul Waquar Ahmed 《Journal of the Geological Society of India》2016,88(6):685-692
The Proterozoic Sirban Limestone Formation (SLFm) crops out as detached allochthons in the northwest Himalaya (Jammu region, India) and has its coeval equivalents laterally disposed in the west in Salt Range, in the northwest in Abbotabad (Pakistan) and in southeast in Himachal Pradesh (India). The oil and gas occurrences have been reported from the Proterozoic successions globally and the hydrocarbon potential of the SLFm cannot be ruled out.The interbedded shales and algal laminated dolostones within the SLFm have yielded microflora comparable to those reported in the North African Neoproterozoic sandstones and the Late Proterozoic carbonates of the giant oil and gas fields of the Siberian Platform. The SLFm contains a rich and diverse biota comprising ~ 10% of the rock volume in thin section. The rich organic assemblage justified a hydrocarbon source potential analysis of the SLFm, tested in this study by Rock Eval (RE) pyrolysis.RE pyrolysis yielded a total organic carbon (TOC) content of 0.02 to 1 wt. % with very low Hydrogen Index (HI) values for the shales and TOC content averaging 0.02 wt. % for the dolostones. The organically lean shales and dolostones exhibit Tmax values indicative of immature to post mature stage. But, since these values are for the samples with complex thermal and tectonic history the results may be unreliable. The highly altered organic matter and kerogen present in the SLFm had the potential to generate hydrocarbons and presently indicates no significant source potential. This study is important for understanding the hydrocarbon occurrences in the SLFm particularly in light of the recent oil and gas discoveries from the coeval Proterozoic successions. 相似文献
47.
Tadahide Ui Norimichi Matsuwo Mari Sumita Akihiko Fujinawa 《Journal of Volcanology and Geothermal Research》1999,89(1-4)
Processes generating block and ash flows by gravitational dome collapse (Merapi-type pyroclastic flow) were observed in detail during the 1990–1995 eruption of Unzen volcano, Japan. Two different types were identified by analysis of video records and observations during helicopter flights. Most of the block and ash flows erupted during the 1991–1993 exogenous dome growth stage initially involved crack propagation due to cooling and flowage of the dome lava lobes. The mass around the crack became unstable, locally decreasing in tensile strength. Finally, a slab separated from the lobe front, fragmented progressively from the base to the top within a few seconds, and became a block and ash flow. Rock falls immediately followed, in response to local instability of the lobe front. Clasts in these rock falls fragmented and merged with the preceding flow. In contrast, block and ash flows during the endogenous dome growth stage in 1994 were generated due to local bulge of the dome. Unstable lava blocks collapsed and subsequently fragmented to produce block and ash flows. 相似文献
48.
Yuki Sugahara Masahumi Kawaguchi Tatsuya Itoyama Daisuke Kurokawa Yasuhiko Tosa Shin-Ichi Kitamura Itsuki C. Handoh Kei Nakayama Yasunori Murakami 《Marine pollution bulletin》2014
Spills of heavy oil (HO) have an adverse effect on marine life. We have demonstrated previously that exposure to HO by fertilized eggs of the pufferfish (Takifugu rubripes) induces neural disruption and behavioral abnormality in early-hatched larvae. Here, two kinds of polycyclic aromatic hydrocarbons, pyrene and phenanthrene, were selected to examine their toxic effects on larval behavior of another pufferfish species (T. niphobles). Larvae exposed to pyrene or phenanthrene exhibited no abnormalities in morphology. However, those exposed to pyrene but not phenanthrene swam in an uncoordinated manner, although their swimming distance and speed were normal. The optic tectum, a part of the midbrain, of pyrene-exposed larvae did not grow to full size. Thus, these findings are indicated that pyrene might be a contributor to the behavioral and neuro-developmental toxicity, although there is no indication that it is the only compound participating in the toxicity of the heavy oil mixture. 相似文献
49.
Optimum delay interval design in delay blasting 总被引:2,自引:0,他引:2
Tatsuya Hoshino Gento Mogi Kou Shaoquan 《Fragblast: International Journal for Blasting and Fragmentation》2000,4(2):139-148
The major concern of this research is the reduction of blast vibrations at certain points of foremost importance. A procedure for optimum delay interval design, considering detonation time errors of the electric detonators, was proposed. Using the relationship between the peak particle velocity (PPV) and the delay at certain points of interest which was calculated by means of a computer program by simulating the superposition of the vibration waves emitted from each borehole, one can usually select the optimal delay interval in order to minimize the PPV. But due to the variations in the actual delay caused by the detonation time errors, the expected PPV usually not only depends on the nominal delay but also on the sensitivity of the PPV. Therefore, the selection of the optimum time interval for a delay blast should be based on both the optimum as well as several sub-optimal time intervals as candidates. In addition, the detonation time errors should be taken into consideration. Also, a new design concept, called 'combined delay blasting', which uses electronic detonators, is proposed to further reduce the PPV at the points of interest. Estimated vibration time histories based on this concept and their PPVs indicated considerably favorable results. 相似文献
50.
Gentaro Kawakami Kenji Nishina Yoshihiro Kase Jun Tajika Keiichi Hayashi Wataru Hirose Tsumoru Sagayama Tatsuya Watanabe Satoshi Ishimaru Ken'ichi Koshimizu Ryo Takahashi Kazuomi Hirakawa 《Island Arc》2017,26(4)
The stratigraphy of tsunami deposits along the Japan Sea, southwest Hokkaido, northern Japan, reveals tsunami recurrences in this particular area. Sandy tsunami deposits are preserved in small valley plains, whereas gravelly deposits of possible tsunami origin are identified in surficial soils covering a Holocene marine terrace and a slope talus. At least five horizons of tsunami events can be defined in the Okushiri Island, the youngest of which immediately overlies the Ko‐d tephra layer (1640 AD) and was likely formed by the historical Oshima‐Ohshima tsunami in 1741 AD. The four older tsunami deposits, dated using accelerator mass spectrometry 14C, were formed at around the 12th century, 1.5–1.6, 2.4–2.6, and 2.8–3.1 ka, respectively. Tsunami sand beds of the 1741 AD and circa 12th century events are recognized in the Hiyama District of Hokkaido Island, but the older tsunami deposits are missing. The deposits of these two tsunamis are found together at the same sites and distributed in regions where wave heights of the 1993 tsunami (Hokkaido Nansei‐oki earthquake, Mw = 7.7) were less than 3 m. Thus, the 12th century tsunami waves were possibly generated near the south of Okushiri Island, whereas the 1993 tsunami was generated towards the north of the island. The estimated recurrence intervals of paleotsunamis, 200–1100 years with an average of 500 years, likely represents the recurrence interval of large earthquakes which would have occurred along several active faults offshore of southwest Hokkaido. 相似文献