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361.
A laboratory study was conducted to examine oil biodegradation in the presence of a fouling organism community. It is shown that the majority of fouling species exhibit relatively weak tolerance to oil. Oil degradation in seawater is shown to proceed quicker and more completely in the presence of the fouling organism community than it does without such organisms. The population of specific bacterial groups is shown first to grow and next decrease as a result of accumulation in water of toxic products of their vital activity. Oil biodegradation is found to cause substantial changes in the water hydrochemical characteristics in experimental vessels.  相似文献   
362.
Conditions of fish reproduction in the Volga–Caspian Basin depending on the hydrological regime in the Volga lower reaches, transformed by water withdrawals and regulatory impact of reservoirs are considered.  相似文献   
363.
Nozzle‐type rainfall simulators are commonly used in hydrologic and soil erosion research. Simulated rainfall intensity, originating from the nozzle, increases as the distance between the point of measurement and the source is decreased. Hence, rainfall measured using rain gauges would systematically overestimate the rainfall received at the ground level. A simple model was developed to adjust rainfall measured anywhere under the simulator to plot‐wide average rainfall at the ground level. Nozzle height, plot width, gauge diameter and height, and gauge location are required to compute this adjustment factor. Results from 15 runs at different rain intensities and durations, and with different rain gauge layouts, showed that a simple average of measured rain would overestimate the plot‐wide rain by about 20 per cent. Using the adjustment factor to convert measured rainfall for individual gauges before averaging improved the estimate of plot‐wide rainfall considerably. For the 15 runs considered, overall discrepancy between actual and measured rain is reduced to less than 1 per cent with a standard error of 0·97 mm. This model can be easily tested in the ?eld by comparing rainfall depths of different sized gauges. With the adjustment factor they should all give very similar values. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
364.
陕西省地下水水质监测发展探析   总被引:1,自引:0,他引:1  
鱼晓利 《地下水》2003,25(1):11-12,25
本文针对陕西省地下水水质监测控制范围局限于农灌区,监测项目单一的现状,通过分析研究,提出水质监测的发展思路,剖析实现新思路的相关条件。  相似文献   
365.
介绍了在利用GPS观测电离层TEC和反演上电离层剖面过程中,如何选择最适宜GPS星,如何计算卫星有关参数,如何计算卫星到测站间斜向TEC等问题,最后给出了一个剖面反演实例。  相似文献   
366.
介绍了GIS在城市轨道交通建设中的应用,分析了轨道交通建设的评价要素和对GIS系统的建设要求提出了系统设计的总体思路和框架及应用前景。  相似文献   
367.
The West Kunlun orogenic belt is located at the conjunction of the paleo-Asian tectonic system and the Tethys tectonic system. Petrological and mineralogical studies of the Early Cambrian metamorphic surface crust in this region have shown that in case the metamorphism reached low-temperature granulate facies, the typical mineral assemblage is biotite-garnet-silimanite-K feldspar-plagioclase-quartz. The peak metamorphic temperatures are within the range of 720–740°C and the pressure is 0.6 GPa ±. Three types of metamorphic zircon have been detected in the metamorphic rocks: the complex inclusion-bearing type ; the early relic zircon inclusion-bearing type; and the inclusion-free type. SHRIMP age determination of these three types of metamorphic zircon have revealed that these zircons were formed principally during 400–460 Ma, indicating that pre-Cambrian metamorphic surface crust rocks underwent low-temperature granulite facies metamorphism during the Caledonian. In combination with the geological characteristics of this region, it is considered that when the oceanic basin was closed, there occurred intense intracontinental subduction (type A), bringing part of the Early Cambrian metamorphic basement in this region downwards to the lower crust. Meanwhile, there were accompanied with tectonic deformation at deep levels and medium- to high-grade metamorphism. This study provided important chronological and mineralogical evidence for the exploration of the evolutionary mechanism and process of the West Kunlun Early Paleozoic. Part of the results from the research project “ Research on the West Kunlun pre-Cambrian tectonic events” under the program “ Research on the important geological problems of China’ s pre-Cambrian” (No. 200113900070) sponsored by the China National Geological Surveying Bureau.  相似文献   
368.
A combined stochastic correlation model for the pole’s motion of a deformable Earth is constructed using the data of the International Earth Rotation Service and dynamical Euler equations taking into account tidal deformations. The deterministic component of the model describes the main regular dynamical effects, while its stochastic component describes irregular effects obeying statistical laws. Linear differential (requiring solutions of ordinary differential equations), and finite (assuming integrated characteristics) correlation models are constructed for both Gaussian and non-Gaussian random parameters. The stochastic oscillations and trend of the Earth’s proper angular velocity are analyzed, as well as nonlinear stochastic oscillations and the trend of the pole. This approach can be considered quite novel.  相似文献   
369.
Comprehensive lithogenetic analysis of the Nyurol paleobasin revealed a large shoal area surrounded by basins. The shoal area is composed of organogenic buildups covered by sediments of isolated and inner lagoons. The organogenic buildups are divided into two types: Stromatopora bioherms and mud-mounds. Regularities of the distribution of organogenic buildups are considered.  相似文献   
370.
The Rainbow hydrothermal field (36° N Mid-Atlantic Ridge) is one of the three presently known fields related to serpentinization of ultramafic rocks accompanied by the formation of hydrogen- and methane-rich solutions. Gas chromatographic (GC) and molecular gas chromatographic–mass spectrometric (GC-MS) investigations of sulfide ores and sediments from this field confirmed a predominantly biological nature of bitumoids related to the high-temperature transformation of biomass of the hydrothermal biological community. At the same time, ores of the Rainbow field contain significant amounts of compounds that are not directly related to biogenic synthesis. This fact suggests the possibility of an abiogenic synthesis of methane and even complex hydrocarbons during the serpentinization of ultramafic rocks.  相似文献   
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