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621.
622.
ZHAO Xingmin SUN Youhong DENG Jian RAO Zhu Lü Cheng SONG Jian Li Lixia 《《地质学报》英文版》2018,92(6):2251-2266
The Mohe permafrost in northeast China possesses favorable subsurface ambient temperature, salinity, Eh values and pH levels of groundwater for the formation of microbial gas, and the Mohe Basin contains rich organic matter in the Middle Jurassic dark mudstones. This work conducted gas chromatography and isotope mass spectrometry analyses of nearly 90 core gas samples from the Mk-2 well in the Mohe Basin. The results show that the dryness coefficient (C1/C1–5) of core hydrocarbon gas from approximately 900 m intervals below the surface is larger than 98%, over 70% of the δ13C values of methane are smaller than ?55‰, and almost all δD values of methane are smaller than ?250‰, indicative of a microbial origin of the gas from almost 900 m of the upper intervals in the Mohe permafrost. Moreover, the biomarker analyses of 72 mudstone samples from the Mohe area indicate that all of them contain 25-norhopane series compounds, thereby suggesting widely distributed microbial activities in the permafrost. This work has confirmed the prevailing existence of microbial gas in the Mohe area, which may be a potential gas source of gas hydrate formation in the Mohe permafrost. This result is of great significance to gas hydrate accumulation in the permafrost across China. 相似文献
623.
In spite of tremendous discoveries of dinosaur eggs and nests over the world, dinosaur embryonic remains are rare. Until today, dinosaur embryos associated with eggshells are only known in about 20 cases, most of which were recovered from broken or crushed eggs. Here we report intact dinosaur eggs in a partial clutch with preserved embryonic remains in eggs from the Upper Cretaceous Nanxiong Formation of Ganzhou in the southern Jiangxi Province of China. Based on macro- and microscopic features of eggs and eggshells, these eggs were identified as Elongatoolithus sp., and possibly belong to oviraptorosaurs. A CT scanning topography revealed that all the eggs contain accumulations of embryonic bones, including possible femur and tibia. Our discovery suggests that dinosaur embryos might be preserved more than we have recognized, because intact eggs potentially confine embryonic remains. 相似文献
624.
M.L.Renjith 《地学前缘(英文版)》2014,5(1):113-126
A systematic account of micro-textures and a few compositional profles of plagioclase from high-alumina basaltic aa lava erupted during the year 1994-1995,from Barren Island Volcano,NE India ocean,are presented for the frst time.The identifed micro-textures can be grouped into two categories:(i)Growth related textures in the form of coarse/fne-sieve morphology,fne-scale oscillatory zoning and resorption surfaces resulted when the equilibrium at the crystal-melt interface was fuctuated due to change in temperature or H2O or pressure or composition of the crystallizing melt;and(ii)morphological texture,like glomerocryst,synneusis,swallow-tailed crystal,microlite and broken crystals,formed by the infuence of dynamic behavior of the crystallizing magma(convection,turbulence,degassing,etc.).Each micro-texture has developed in a specifc magmatic environment,accordingly,a frst order magma plumbing model and crystallization dynamics are envisaged for the studied lava unit.Magma generated has undergone extensive fractional crystallization of An-rich plagioclase in stable magmatic environment at a deeper depth.Subsequently they ascend to a shallow chamber where the newly brought crystals and pre-existing crystals have undergone dynamic crystallization via dissolution-regrowth processes in a convective selfmixing environment.Such repeated recharge-recycling processes have produced various populations of plagioclase with different micro-textural stratigraphy in the studied lava unit.Intermittent degassing and eruption related decompression have also played a major role in the fnal stage of crystallization dynamics. 相似文献
625.
正Lop Nur is located in the interior of Asian and the lowest part in the eastern Tarim Basin.It is the final destination of major river systems in Tarim Basin and the accumulation center of salt materials(Xia,1987).As 相似文献
626.
一、前言 ECMWF(以下简称中心)的第一个业务模式是网格点模式,分辨率为经、纬向1.875°,垂直方向15层,于1979年8月1日开始做每周5天的业务预报,从1980年8月1日起开始做每周7天的业务预报。第二个业务模式是一个谱模式,于1983年4月21日投入业务使用。 相似文献
627.
Guo-Liang Lü 《中国天文和天体物理学报》2011,11(3)
By simulating the evolution of spin periods of magnetized neutron stars which interact with their environment in binary systems,we investigate the Galactic population of high mass X-ray binaries(HMXBs) .The number of HMXBs in the Galaxy is between 190 and 240,and their birthrate is from 5.9×10-5 yr-1 to 6.3× 10-5 yr-1.Comparing the Corbet diagram(the positions of the spin periods vs.the orbital periods of HMXBs) in our model with the associated observations,we find that the stellar wind structure and the pr... 相似文献
628.
Gordon E. Sarty Bogumil Pilecki Daniel E. Reichart Kevin M. Ivarsen Joshua B. Haislip Melissa C. Nysewander Aaron P. LaCluyze Helen M. Johnston Robert R. Shobbrook Lászl L. Kiss Kinwah Wu 《中国天文和天体物理学报》2011,(8)
We searched for long period variation in V-band,IC-band and RXTE X-ray light curves of the High Mass X-ray Binaries(HMXBs) LS 1698 /RX J1037.5-5647,HD 110432 /1H 1249-637 and HD 161103 /RX J1744.7-2713 in an attempt to discover orbitally induced variation. Data were obtained primarily from the ASAS database and were supplemented by shorter term observations made with the 24-and 40-inch ANU telescopes and one of the robotic PROMPT telescopes. Fourier periodograms suggested the existence of long period variat... 相似文献
629.
Li-Cai Deng Heidi Jo Newberg Chao Liu Jeffrey L. Carlin Timothy C. Beers Li Chen Hsu-Tai Lee Carl J. Grillmair Puragra Guhathakurta Zhan-Wen Han Jin-Liang Hou Sebastien Lepine Jing Li Xiao-Wei Liu Kai-Ke Pan J. A. Sellwood Bo Wang Hong-Chi Wang Fan Yang Brian Yanny Hao-Tong Zhang Yue-Yang Zhang Zheng Zheng Zi Zhu 《天体物理学报》2012,(7):735-754
630.
On the universal third order Stokes wave solution 总被引:1,自引:0,他引:1
This paper presents a universal third-order Stokes solution with uniform current. This solution is derived on the basis of potential theory by expanding the free surface and potential function in Fourier series and determining the Fourier coefficients by solving a set of nonlinear algebraic equations through the Taylor expansion and perturbation method. The universal solution is expressed upon the still water depth with the still water level as datum and retains a global perturbation parameter. The wave set-up term generated by the self-interaction of oscillatory waves is explicitly included in the free surface function. With the use of different definitions for the wave celerity, different water levels as the datum, different non-dimensional variables as the perturbation parameter, and different treatments for the total head, the universal solution can be reduced to the existing various Stokes solutions, thus explaining the reasons and the physical significance of different non-periodic terms in them, such as the positive or negative constant term in the free surface expression and the time-or space-proportional term in the potential function. 相似文献