排序方式： 共有12条查询结果，搜索用时 15 毫秒
1.
1 研究背景
已有研究表明,在中强及以上地震前,在震中距一定范围内分布的氡测点通常会出现氡异常,表明氡测项映震效果较好(廖丽霞,2008;孙凤霞等,2016).虽然诸多地震预报研究涉及水氡测项映震前兆机理分析及方法探索,但对于水氡动态变化异常分析及判断,尚缺少有效实例.因此,本文就2017年4月12日浙江临安MS 4.2地震前安徽香泉地震台水氡测值异常变化进行探讨,以期准确捕捉前兆异常信息,提升地震分析预报能力. 相似文献
2.
He Daming Centre for Environmental Evolution Sustainable Development Yunnan Institute of Geography Kunming China Hsiang te Kung Memphis University TN USA 《地理学报(英文版)》1997,(4)
Ｉ.ＨｙｄｒｏｇｅｏｇｒａｐｈｉｃａｌＣｈａｒａｃｔｅｒｉｓｔｉｃｓＴｈｅＬａｎｃａｎｇＭｅｋｏｎｇＲｉｖｅｒｏｒｉｇｉｎａｔｅｓｆｒｏｍａｓｍａｌｌｇｌａｃｉｅｒｏｆ0.4ｋｍ2ｉｎａｒｅａａｔａｎｅｌｅｖａｔｉｏｎｏｆ5167ｍｉｎＬａｓａｉｇｏｎｇｍａＭｏｕｎｔａｉｎ(ａｌｓｏｃａｌｌｅｄＺｈａｉｃｕｏＭｏｕｎｔａｉｎ)ａｔｎｏｒｔｈｅｒｎｆｏｏｔｏｆＴａｎｇｇｕｌａＭｏｕｎｔａｉｎＲａｎｇｅｗｉｔｈｉｎＺａｄｕｏＣｏｕｎｔｙ,ＹｕｓｈｕＴｉｂｅｔａｎＡｕｔｏｎｏｍｏｕｓＰｒｅｆｅｃｔｕｒｅ,Ｑｉｎｇ… 相似文献
3.
Improvements to Griggs-type apparatus for mechanical testing at high pressures and temperatures 总被引：2，自引：0，他引：2
Tracy N. Tingle Harry W. Green Jr. Thomas E. Young Ted A. Koczynski 《Pure and Applied Geophysics》1993,141(2-4):523-543
New and improved techniques and apparatus for testing the mechanical properties of materials at high presures and temperatures are described. These include an improved Griggs-type deformation apparatus designed to operate to 5 GPa and associated servo-controlled hydraulic drive and electronics, the design of hydrostatic (molten alkali halide mixtures) pressure assemblies to measure flow stresses as low as a few MPa, the characterization of temperature gradients and friction in such assemblies, measurement of the melting curve of an alkali halide mixture used as a confining pressure medium, and the measurement of acoustic emissions. 相似文献
4.
Jay M. Pasachoff Evan D. Tingle Ingolf E. Dammasch Alphonse C. Sterling 《Solar physics》2011,268(1):151-163
Using mainly the 1600 Å continuum channel and also the 1216 Å Lyman-α channel (which includes some UV continuum and C iv emission) aboard the TRACE satellite, we observed the complete lifetime of a transient, bright chromospheric loop. Simultaneous observations with the SUMER instrument aboard the SOHO spacecraft revealed interesting material velocities through the Doppler effect existing above the chromospheric loop imaged with TRACE, possibly corresponding to extended nonvisible loops, or the base of an X-ray jet. 相似文献
5.
T N Tingle 《Chemical Geology》1998,147(1-2):3-10
The abundance of C in carbonaceous and ordinary chondrites decreases exponentially with increasing shock pressure as inferred from the petrologic shock classification of Scott et al. [Scott, E.R.D., Keil, K., Stoffler, D., 1992. Shock metamorphism of carbonaceous chondrites. Geochim. Cosmochim. Acta 56, 4281-4293] and Stoffler et al. [Stoffler, D., Keil, K., Scott, E.R.D., 1991. Shock metamorphism of ordinary chondrites. Geochim. Cosmochim. Acta 55, 3845-3867]. This confirms the experimental results of Tyburczy et al. [Tyburczy, J.A., Frisch, B., Ahrens, T.J., 1986. Shock-induced volatile loss from a carbonaceous chondrite: implications for planetary accretion. Earth Planet. Sci. Lett. 80, 201-207] on shock-induced devolatization of the Murchison meteorite showing that carbonaceous chondrites appear to be completely devolatilized at impact velocities greater than 2 km s-1. Both of these results suggest that C incorporation would have been most efficient in the early stages of accretion, and that the primordial C content of the Earth was between 10(24) and 10(25) g C (1-10% efficiency of incorporation). This estimate agrees well with the value of 3-7 x 10(24) g C based on the atmospheric abundance of 36Ar and the chondritic C/36Ar (Marty and Jambon, 1987). Several observations suggest that C likely was incorporated into the Earth's core during accretion. (1) Graphite and carbides are commonly present in iron meteorites, and those iron meteorites with Widmanstatten patterns reflecting the slowest cooling rates (mostly Group I and IIIb) contain the highest C abundances. The C abundance-cooling rate correlation is consistent with dissolution of C into Fe-Ni liquids that segregated to form the cores of the iron meteorite parent bodies. (2) The carbon isotopic composition of graphite in iron meteorites exhibits a uniform value of -5% [Deines, P., Wickman, F.E. 1973. The isotopic composition of 'graphitic' carbon from iron meteorites and some remarks on the troilitic sulfur of iron meteorites. Geochim. Cosmochim. Acta 37, 1295-1319; Deines, P., Wickman, F.E., 1975. A contribution to the stable carbon isotope geochemistry of iron meteorites. Geochim. Cosmochim. Acta 39, 547-557] identical to the mode in the distribution found in diamonds, carbonatites and oceanic basalts [Mattey, D.P., 1987. Carbon isotopes in the mantle. Terra Cognita 7, 31-37]. (3) The room pressure solubility of C in molten iron is 4.3 wt% C. Phase equilibria confirm that the Fe-C eutectic persists to 12 GPa, and thermochemical calculations for the Fe-C-S system by Wood [Wood, B.J., 1993. Carbon in the core. Earth Planet. Sci. Lett. 117, 593-607] predict that C is soluble in Fe liquids at core pressures. The abundance of 36Ar in chondrites decreases exponentially with increasing shock pressure as observed for C. It is well known that noble gases are positively correlated and physically associated with C in meteorites [e.g. Otting, W., Zahringer J., 1967. Total carbon content and primordial rare gases in chondrites. Geochim. Cosmochim. Acta 31, 1949-1960; Reynolds, J.H., Frick, U., Niel, J.M., Phinney, D.L., 1978. Rare-gas-rich separates from carbonaceous chondrites. Geochim. Cosmochim. Acta, 42, 1775-1797]. This suggests a mechanism by which primordial He and other noble gases may have incorporated into the Earth during accretion. The abundance of He in the primordial Earth required to sustain the modern He flux for 4 Ga (assuming a planetary 3 He/4 He; Reynolds et al. [Reynolds, J.H., Frick, U., Niel, J.M., Phinney, D.L., 1978. Rare-gas-rich separates from carbonaceous chondrites. Geochim. Cosmochim. Acta 42, 1775-1797] is calculated to be > or = 10(-8) cm3 g-1. This minimum estimate is consistent with a 1-10% efficiency of noble gas retention during accretion and the observed abundance of He in carbonaceous chondrites (10(-5) to 10(-4) cm3 g-1 excluding spallogenic contributions). 相似文献
6.
Integrated Futures for Europe’s Mountain Regions: Reconciling Biodiversity Conservation and Human Livelihoods 总被引：1，自引：1，他引：0
Introduction Europe's mountains cover nearly half of the continent's area (Price et al. 2004) and land cover varies significantly (European Commission 2004). In most massifs, except for Sicily, southern Greece, and the British Isles, forest cover is dominant. In northern Europe, grassland is proportionately more important, and much of the mountains of the British Isles is covered by moorland. In central and southern Europe, arable land is of far greater importance than grassland, with Med… 相似文献
7.
Tracy N. Tingle Christopher H. Becker Ripudaman Malhotra 《Meteoritics & planetary science》1991,26(2):117-127
Abstract— Organic compounds in the Murchison (C2M) and Allende (CV3) carbonaceous chondrites were analyzed by photoionization time-of-flight mass spectrometry; thermal (25–850 °C) and stimulated (7 keV Ar+) desorption were combined with either nonresonant single-photon ionization using 118 nm light or resonantly enhanced multiphoton ionization (selective for aromatic compounds) using 266 nm light. Samples weighing only 1–10 mg were sufficient for sensitive quantitative analysis of aromatic compounds using thermal desorption. The detection limits for phenanthrene and pyrene using 118 nm light were determined to be 0.8 and 1.4 picomoles, respectively, and the concentrations of these compounds (including their isomers anthracene and fluoranthene) in the Murchison meteorite were determined to be 9 and 12 μg/g, respectively, in good agreement with previously published values. Thermal-desorption (–75–500 °C) field-ionization mass spectra (activated foil-type ionizing source and magnetic sector mass analyzer) of 20–40 mg of the same meteorite material were obtained to verify that the 118 nm photoionization mass spectra were not affected by photofragmentation or photodecomposition and were representative of the organic material extracted by thermal desorption. Photoionization mass spectrometry is a useful technique for studying small quantities (< 1 nanomole) of organic matter in terrestrial and extraterrestrial samples. The present study aims to provide the background and analytical methods necessary for application to new and unsolved cosmochemical problems. Some potential applications are discussed. 相似文献
8.
Catherine Dupas-Bruzek Tracy N. Tingle Harry W. Green II. Nicole Doukhan Jean-Claude Doukhan 《Physics and Chemistry of Minerals》1998,25(7):501-514
Synthetic polycrystals of α-Mg2GeO4 (with the olivine structure) and γ-Mg2GeO4 (with the spinel structure) deformed at high temperature and pressure in their respective stability fields were investigated by analytical transmission electron microscopy. Specimens with a mean grain size of 20–30 µm deform by dislocation glide and/or climb. The predominance of glide versus climb depends on stress and grain orientation. The defect microstructures of both polymorphs are very similar to those observed in their respective silicate analogues, α- and γ-(Mg,Fe)2SiO4, and, in the case of the spinel phase, very similar to those observed in magnesium aluminate spinels. These observations suggest that Mg2GeO4 is a good rheological analogue for the Earth’s upper mantle. A spinel specimen deformed under the same conditions of temperature and strain rate as an olivine specimen was approximately three times stronger than olivine. In specimens of both phases deformed at or above 1400 K, a thin amorphous film composed of Mg, Ge, and O was detected along some grain boundaries. Grains ≤10 µm diameter surrounded by a film of amorphous phase (>10 nm thick) exhibited low dislocation densities, and deformation appeared to have occurred by grain boundary sliding. 相似文献
9.
It has been suggested that the formation of reduced carbonaceous matter in basalts and mantle xenoliths occurs by heterogeneous reaction of volcanic gas on fresh, chemically active crack surfaces produced by thermal stresses during eruption and cooling. This hypothesis is supported by experiments at 400-800 degrees C on ?010? surfaces of San Carlos olivine exposed to C-O-H gases generated by the decomposition of oxalic acid and oxalic acid dihydrate. Carbonaceous films form readily on these surfaces and achieve thicknesses comparable to those observed in natural samples (a few nanometers) in a matter of minutes. At relatively oxidizing conditions, the carbonaceous films consist principally of C-C and C-H bonded species with lesser amounts of C-O bonded species. At relatively reducing conditions, the carbonaceous films consist of subequal amounts of C-C/C-H, C-O, and metal-C species. Aliphatic and aromatic hydrocarbons and other thermally labile organic species are associated with carbonaceous films in some natural samples but none were detected in experimental samples from this study, leaving open the question of abiotic synthesis of organic matter on crack surfaces in basalts. Regardless, it is clear from the preliminary experiments reported here that crack surfaces in olivine (and probably other silicate minerals and glasses) are capable of stabilizing compounds that otherwise would not be stable in cooling lava. 相似文献
10.
Southwest China and Southeast Asia: towards sustainability through cooperative development and management of international rivers * 总被引：1，自引：0，他引：1
HE Daming Yunnan Institute of Geography Yunnan Kunming CHINA Dept. of Geography the University of Memphis Memphis TN USA Hsiange te Kung Dept. of Geography the University of Memphis Memphis TN USA 《地理学报(英文版)》1998,(3)
Ｉ．ＩｎｔｅｒｎａｔｉｏｎａｌＲｉｖｅｒｓａｎｄｔｈｅＬａｎｃａｎｇＭｅｋｏｎｇＲｉｖｅｒＩｎｔｅｒｎａｔｉｏｎａｌｒｉｖｅｒｓａｒｅｄｅｆｉｎｅｄａｓｔｈｅｒｉｖｅｒｓｗｈｉｃｈｆｌｏｗａｃｒｏｓｔｗｏｏｒｔｗｏｍｏｒｅｃｏｕｎｔｒｉｅｓ．Ｕｐｔ... 相似文献