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131.
Li Peixian Su Deying Li Yougui Yu JingxianInstitute of Geology Chinese Academy of Geological Sciences Beijing 《《地质学报》英文版》1994,68(3):329-349
In the Yanliao area, the occurrence of the Nestoria-Keratestheria fauna and the Eoparacypris- Luanpingella-Darwinula assemblage in the Dabeigou Formation s.s., a Rb-Sr isochron age of 145.2 Ma for the Baiqi Formation and a complete stratigraphic sequence-all this proves that the Lycoptera-bearing bed overlies the Upper Jurassic. The Jehol fauna comprises the primitive Trigonioidids fauna, Eosestheria fauna, Lycoptera fauna et al., and their own laws of evolution expound that they belong to Cretaceous faunas. The associations of Eosestheria with Yanjiestheria, Lycoptera with Eosestheria, and Kuntulunia with Yanjiestheria as well as the occurrence of early angiosperms and sporo - pollen in the Fuxin Formation and its equivalents also demonstrate that the Lycoptera-bearing, bed should be assigned to the Cretaceous. The confirmation of the existence of Aucellina in the Jixi Group and the correlation of Trigonioidids and Cypridids with those in the equivalent strata of Japan and Western Europe have also been 相似文献
132.
Summary Techniques presented herein show how reflected voltage pulses from coaxial antenna cable grouted in rock masses can be employed to quantify the type and magnitude of rock mass deformation. This measurement is similar to that obtained from a combined full profile extensometer (to measure local extension) and inclinometer (to measure local shearing). Rock mass movements deform the grouted cable, which locally changes cable capacitance and thereby the reflected wave form of the voltage pulse. Thus, by monitoring changes in these reflection signatures, it is possible to monitor rock mass deformation.This paper presents laboratory measurements necessary to quantitatively interpret the reflected voltage signatures. Cables were sheared and extended to correlate measured cable deformation with reflected voltage signals. Laboratory testing included development of grout mixtures with optimum properties for field installation and performance of a TDR (Time Domain Reflectometry) monitoring system. Finally, the interpretive techniques developed through laboratory measurements were applied to previously collected field data to extract hitherto unrealized information. 相似文献
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永安小磉调查区大面积出露外来推覆体即寒武系中一下统林田组、上统东坑口组,泥盆系上统天瓦崃组、桃子坑组,石炭系下统林地组、中统黄龙组、上统船山组,利用推覆构造理论,并结合深部钻探验证,推覆体下保存较厚煤系(童子岩组)和可采煤层,找煤潜力大,推覆构造理论对指导深部找煤具有重要意义。 相似文献
135.
工业革命以来人类活动产生了大量二氧化碳气体(CO2)并释放到大气中。CO2溶于海水,造成海水pH值降低,改变海洋碳酸系统的平衡。海洋酸化对海洋生态系统特别是钙化生物构成威胁。颗石藻作为主要的钙化浮游生物,在海洋碳循环过程中起着重要的作用。大多数培养实验表明CO2浓度上升会促进颗石藻光合作用。而海洋酸化对不同种或不同品系颗石藻钙化作用产生不同的影响。 相似文献
136.
Hong-Bing Su Hans Peter Schmid C. S. B. Grimmond Christoph S. Vogel Andrew J. Oliphant 《Boundary-Layer Meteorology》2004,110(2):213-253
We present turbulence spectra and cospectra derived from long-term eddy-covariancemeasurements (nearly 40,000 hourly data over three to four years) and the transferfunctions of closed-path infrared gas analyzers over two mixed hardwood forests inthe mid-western U.S.A. The measurement heights ranged from 1.3 to 2.1 times themean tree height, and peak vegetation area index (VAI) was 3.5 to 4.7; the topographyat both sites deviates from ideal flat terrain. The analysis follows the approach ofKaimal et al. (Quart. J. Roy. Meteorol. Soc.
98, 563–589, 1972) whose results were based upon 15 hours of measurements atthree heights in the Kansas experiment over flatter and smoother terrain. Both thespectral and cospectral constants and stability functions for normalizing and collapsingspectra and cospectra in the inertial subrange were found to be different from those ofKaimal et al. In unstable conditions, we found that an appropriate stabilityfunction for the non-dimensional dissipation of turbulent kinetic energy is of the form () = (1 - b-)-1/4 - c-, where representsthe non-dimensional stability parameter. In stable conditions, a non-linear functionGxy() = 1 + bxyc
xy (cxy < 1) was found to benecessary to collapse cospectra in the inertial subrange. The empirical cospectralmodels of Kaimal et al. were modified to fit the somewhat more (neutraland unstable) or less (stable) sharply peaked scalar cospectra observed over forestsusing the appropriate cospectral constants and non-linear stability functions. Theempirical coefficients in the stability functions and in the cospectral models varywith measurement height and seasonal changes in VAI. The seasonal differencesare generally larger at the Morgan Monroe State Forest site (greater peak VAI) andcloser to the canopy.The characteristics of transfer functions of the closed-path infrared gas analysersthrough long-tubes for CO2 and water vapour fluxes were studied empirically. This was done by fitting the ratio between normalized cospectra of CO2 or watervapour fluxes and those of sensible heat to the transfer function of a first-order sensor.The characteristic time constant for CO2 is much smaller than that for water vapour. The time constant for water vapour increases greatly with aging tubes. Three methods were used to estimate the flux attenuations and corrections; from June through August, the attenuations of CO2 fluxes are about 3–4% during the daytime and 6–10% at night on average. For the daytime latent heat flux (QE), the attenuations are foundto vary from less than 10% for newer tubes to over 20% for aged tubes. Correctionsto QE led to increases in the ratio (QH + QE)/(Q* - QG) by about 0.05 to0.19 (QH is sensible heat flux, Q* is net radiation and QG is soil heat flux),and thus are expected to have an important impact on the assessment of energy balanceclosure. 相似文献
137.
豫北“21·7”极端暴雨过程特征及成因分析 总被引:1,自引:0,他引:1
利用探空、地面自动站、多普勒雷达等观测资料及ERA5再分析产品,对2021年7月17—22日豫北地区的极端暴雨过程进行分析。结果表明,极端暴雨过程具有强降水持续时间长、降水强度极端及地形影响明显等特征。极端暴雨过程发生于稳定的大尺度天气形势下,在日本海高压西伸及台风烟花(2106号)、查帕卡(2107号)西北行背景下,黄淮低涡外围加强北上的东南急流/偏南急流为强降水的发生提供了异常充足的水汽、能量条件,对流层中低层暖湿平流强迫、叠加地形影响的强动力辐合抬升作用及低空弱冷空气扩散南下是形成强降水的重要条件,而大气“强-弱-强-弱”的对流不稳定层结特征转化说明强降水过程中存在着两种互补的物理机制。不同阶段极端短时强降水(小时降水量≥50 mm)对流系统的形态结构和发展演变特征不同,但从雷达回波的垂直分布来看,系统均具有“低质心”特征,质心强度≥55 dBz且≥50 dBz强回波垂直伸展至5~8 km、持续时间1 h以上。强降水对流系统在太行山前30 km左右范围内的后向发展特征明显,一方面与地面西行偏东风/东北风在太行山绕流作用下形成的地形辐合线不断南伸有关,另一方面也与强降水冷池效应促使... 相似文献
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139.
Results of our aerosol study, performed during 1983-1984 in Beijing, demonstrate that ambient carbonaceous aerosols are derived mainly from coal combustion. Different SO, oxidation processes have been observed in summer and winter. The winter sulfate appears to be produced locally and associated with products of incomplete combustion. 相似文献
140.