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61.
用差热和热(失)重法、pH值检验、离子色谱等分析方法考察和证实了Cl-对平菲尔特管重量法测定化合水(H2O+)的干扰,研究其影响规律,提出用系数校正方法可获得H2O+的准确结果。方法用于含氯深海沉积物和大洋多金属结核标准物质中H2O+的定值分析,取得满意结果 相似文献
62.
文章是对ISO9001标准精神的一些理解,并对该标准中一些条文规定展开讨论。 相似文献
63.
We measured the partial pressure of oxygen (PO2) in the interstitial gas surrounding the sand-swimming Namib moleEremitalpa granti namibensis. At a sand temperature of 26 °C, which produced a nearly maximal rate of oxygen consumption, thePO2near the noses of the animals averaged only 0·9 kPa (6·7 Torr) below the level in the free atmosphere. High oxygen availability was a result of the notably low metabolic rate in the 20 g mammals and the dry, porous and metabolically inactive nature of dune sand. A mathematical model indicated that normal mammals weighing 200 g or more could comfortably exist completely encased in dune sand. We concluded that the moles' small size and low metabolic rate are not adaptations to hypoxia or hypercapnia underground but are probably related to low food availability and the energetic cost of foraging in their desert environment. 相似文献
64.
Oxygen Isotope Exchange Kinetics Between Coexisting Minerals and Water in the Aral Granite Pluton of the Altay Mountains, Northern Xinjiang 总被引:2,自引:0,他引:2
Liu Wei Research Center of Mineral Resources Exploration Chinese Academy of Sciences Chinese Academy of Sciences BeijingHe Baichu Changsha Institute of Geotectonics Chinese Academy of Sciences Changsh Hunanand Chen ZhenshengYichang Institute of Geology Mineral Resources Chinese Academy of GeologicalSciences Yichang Hubei 《《地质学报》英文版》1996,70(4)
Coexisting quartz, feldspar and biotite vary widely in their δ18O values and display a remarkable 18O/16O disequilibrium relation; especially, a quartz-feldspar reversal (△ 18OQUartz_feldspar< 0) exsists in the Aral granite pluton of the Altay Mountains, northern Xinjiang. The 18O / 16O exchange reaction definitely occurred between granite and water. Initial δ18O values of the granite and exotic fluid are evaluated by the mass balance consideration. The conventional method of discrimination between various magma derivations simply with δ18O values of either whole rock or separate minerals is misleading and unreliable. Experiments carried out by the authors show that the 18O / 16O exchange reaction is not accompanied by what geologists describe as petrological and mineralogical alteration effect. This decoupling relation implies that exchange reaction occurs at a relatively high temperature during subsolidus-postmagmatic cooling of magmas. The exchange mechanism is mainly diffusion-controlled. It is 相似文献
65.
应用Kriging方法研究格尔木河流域地下水位动态观测网的优化配置 总被引:4,自引:0,他引:4
地下水动态是水文地质研究的一个重要方面,如何获满足一定精度要求全面而合理的地下水位动态资料具有现实经济效益。本文研究格尔木河流域地下水位动态测网,通过选取理想的变差函,运有Kriging方法进行地下水位的线性无偏最优估计和计算估计误差的标准差,结合给定的允许误差限评判地下水位动态观测网的配置是否合适,并提出调整现有观测网的方案 相似文献
66.
Jürg W. Schlatter Alfred Wüest Dieter M. Imboden 《Aquatic Sciences - Research Across Boundaries》1997,59(3):225-242
The artificial tracer sulphur hexafluoride (SF6) has been used to study the density-driven deep water exchange between two sill-separated basins of Lake Lucerne, Gersauersee and Urnersee. The sources of the density gradients between the two basins are (1) salinity differences between the major inlets due to the different geology of their drainage areas, and (2) temperature differences due to spatial variation of wind forcing. Wind speeds are generally larger in Urnersee, especially in spring during the so-called Föhn events, when winds blow from the south. In contrast, Gersauersee is protected form these winds. In spring 1989, a total of 630 g of SF6 was released at 80 to 120 m depth in the small Treib Basin located between Urnersee and Gersauersee. During about 100 days the distribution of SF6 in the lake was determined by gaschromatography. Two models are used to quantify the exchange flow, (1) a one-box mass balance model for SF6 in the deep part of Treib Basin, and (2) a one-dimensional diffusion/advection model describing the temporal and vertical temperature variation in Urnersee. According to the first model, the flow into the deep hypolimnion of Urnersee, decreases from 21·106 m3·d?1 at the end of March to about 8·106 m3·d?1 in late April. The second model yields similar flow rates. The decrease of the flow rate during spring, confirmed by both approaches, is consistent (1) with the decreasing strength of the density gradient above the sill during spring and early summer, and (2) with hydrographic information collected in Lake Lucerne during other years. 相似文献
67.
概述了同位素封闭体系内的矿物氧扩散和同位素交换机制及其在地质速率计上的应用。火成岩从高温冷却或变质岩从高峰主质温度冷却过程中,由于冷却速度不同,扩散作用导致的矿物晶体内部及晶粒间氧同位素再平衡也有所不同。通过实测岩石中各组成矿物氧同位素比值,模式含量和颗粒半径,据矿物氧扩散和同位素交换模型,可以估算出岩石的冷却速率。 相似文献
68.
Variability in water-exchange time between Tokyo Bay and the Pacific Ocean during winter is investigated based on the results of intensive field observation from November 2000 to March 2001. Water-exchange time between Tokyo Bay and the Pacific Ocean during winter mainly depends on the strength of northerly monsoon, being about 16 days under the weak monsoon and about 12 days under the strong monsoon. Moreover, it becomes longer by about 1 day in spring tide and shorter in neap tide due to the coupling effect of estuarine circulation and vertical mixing. Water-exchange time also varies depending on the open-ocean condition. When the warm water mass approaches from the Pacific Ocean to the mouth of Tokyo Bay through the eastern channel of Sagami Bay, which connects Tokyo Bay and the Pacific Ocean, water-exchange time becomes longer by about 2 days because the warm water mass is blocked in the surface layer at the bay mouth. On the other hand, when the warm water mass approaches to the mouth of Tokyo Bay through the western channel of Sagami Bay, water-exchange time becomes shorter by about 1 day because the warm water mass intrudes into the middle or lower layers of Tokyo Bay. Such different behavior of warm water mass at the mouth of Tokyo Bay is due to the difference in density of approaching warm water masses, that is, the density of the warm water mass through the eastern channel is smaller than that of the warm water mass through the western channel of Sagami Bay.Responsible Editors: Yens Kappenberg 相似文献
69.
物理实验中的不确定度评定 总被引:2,自引:0,他引:2
阐述了不确定度的定义、来源、分类及用不确定度评定测量结果的一些表示方法。分析了误差和不确定度的区别。最终给出了测量不确定度的评定。 相似文献
70.
利用 1 956~ 2 0 0 0年舟山市定海验潮站潮位观测资料 ,对历年影响舟山的台风风暴潮灾进行了全面的统计分析。将台风按路径分型 ,分析了不同路径台风风暴潮的特点 ,并用基于PRESS准则的逐步回归方法 ,建立了不同路径风暴潮的预报模型。 相似文献