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71.
72.
实验考察了8种市售水溶性破乳荆对长庆油田陕北区有代表性的宝塔区、安塞和子长原油(均为低硫中间基-石蜡基原油)的脱水效果(加量100mg/L,脱水温度55℃,时间3h)。目前长庆采油一厂使用的YT-100和延炼集团使用的GT-940对这3种原油的脱水效果均较好,但对子长原油的脱水率不高,分别为69.7%和58.9%。在由所选性能较好的破乳刺组成的4种二元复配物中,GT-940 HQ96-1对3种原油的脱水效果均高于单剂,最佳配比分别为4:1,4:1,3:2;其余3种复配物则对原油有选择性,其中GT-940 YT-100相近(97.5%);YT-100 HQ96-1仅能改善子长原油的脱水效果,配比为4:1时脱水率最高(76.4%);SP-169 HQ96-1仅能改善宝塔区原油的脱水效果.配比3:2和2:3时脱水率最高(92.9%)。表5参6。 相似文献
73.
Learning and memory of novel spatial configurations aids behaviors such as visual search through an implicit process called contextual cuing (M. M. Chun & Y. Jiang, 1998). The present study provides rigorous tests of the implicit nature of contextual cuing. Experiment 1 used a recognition test that closely matched the learning task, confirming that memory traces of predictive spatial context were not accessible to conscious retrieval. Experiment 2 gave explicit instructions to encode visual context during learning, but learning was not improved and conscious memory remained undetectable. Experiment 3 illustrates that memory traces for spatial context may persist for at least 1 week, suggesting a long-term component of contextual cuing. These experiments indicate that the learning and memory of spatial context in the contextual cuing task are indeed implicit. The results have implications for understanding the neural substrate of spatial contextual learning, which may depend on an intact medial temporal lobe system that includes the hippocampus (M. M. Chun & E. A. Phelps, 1999). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
74.
招远金矿集中区是我国最大的金矿集中区,区内金矿床在时间和空间上的分布规律十分明显。该区矿化类型主要有石英脉型、蚀变岩型及二者之间的过渡类型,其在空间上的分布规律为综合信息找矿及矿床定位预测提供地质信息,并可作为进一步的找矿标志。 相似文献
75.
Exposure to turbulence, an environmental stimulus, produces behavioral adaptation in the Aplysia siphon-withdrawal response (SWR). The authors show that the duration and spatial extent of turbulence influence adaptation recovery. In terms of duration, recovery in whole animals and reduced preparations (tail, siphon, and CNS) was more rapid after longer exposures to turbulence (10 min) than after briefer exposures (10 s-5 min). In terms of spatial extent, recovery in reduced preparations was more rapid after diffuse turbulence (tail and siphon together) compared with focal turbulence (siphon alone). Furthermore, spatial extent and duration interact: Duration regulates recovery only when turbulence is diffuse. Results suggest that SWR adaptation reflects a composite of cellular processes, including short-term synaptic enhancement in L30 inhibitory interneurons. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
Qijun Zhao 《Pattern recognition》2006,39(2):310-312
In this paper, we propose a fast Evolutionary pursuit algorithm. It searches for optimal discriminant vectors through linearly combining standard bases. Experiments on the Yale and ORL databases verify its effectiveness and enhanced efficiency. 相似文献
77.
高功率激光系统通过空间滤波和中继成像抑制自聚焦 总被引:3,自引:1,他引:2
孟昭贤 《激光与光电子学进展》1998,35(9):8-12
讨论了由光束自聚焦引起的细丝形成和光束分裂,为了克服聚焦造成的破坏要求在光束传播中采用中继成像和空间滤波。 相似文献
78.
E. J. Wisniewski and G. L. Murphy (see record 2004-22496-015) suggested that the apparent effects of relation frequency in C. L. Gagné and E. J. Shoben's (1997; see record 1997-02349-004) conceptual combination experiments could be explained by differences between the familiarity and plausibility of their stimuli (noun-noun phrases). However, C. L. Gagné and T. L. Spalding (see record 2006-20573-017) argued that Wisniewski and Murphy's measures of plausibility and frequency are both sensitive to relation frequency. They also suggested that the stimuli were mostly novel, such that differences in familiarity could not explain Gagné and Shoben's findings. The current authors focus on the theoretical rationale for the plausibility and familiarity variables, arguing that the original interpretation of their findings is correct. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
79.
多专题多比例尺水系河网管理模型研究 总被引:2,自引:0,他引:2
随着水利行业GIS系统的快速发展和对性能要求的不断提高,迫切需要解决多比例尺水系河网信息统一访问、关系维护等问题。本文提出多专题多比例尺地图管理模型,通过对地图信息依据不同比例尺和专题进行目录层次和专题层次的划分,实现水系河网信息的全国分布式统一管理和共享系统。文中给出了该模型下的水系河网表示和专题中对象间关系,分析了为形成一套基于空间数据库和空间化分析方法的分布式水系河网信息共享系统所需进行的下一步工作。该模型下的全国水系河网管理系统具有较好的可扩展性,支持有效获取不同比例尺的地图,较少信息冗余和保证信息最大可能。 相似文献
80.
Processes affecting fish populations range in scale from local to global. Fish response is also scale‐dependent, with some activities varying locally while others depend on large‐scale connectivity within or between watersheds. These issues are still only partly recognized, with large‐scale research often affected by non‐independent sampling, weak inference, poor model testing or model over‐extrapolation. Available multi‐scale studies can reach different conclusions about factors affecting fishes from local studies, but results vary between examples. Potential explanations are (i) effects on fishes are context‐dependent; (ii) different species or life‐stages are limited in different ways; (iii) multi‐scale studies are too few for generalization. We advocate improved use of geostatistical tools to guide sampling or interpret the spatial extent of management problems, and we illustrate this using brown trout in Welsh streams. Our strongest recommendation is that fish ecologists recognize the importance of interactions across scales in quantifying effects on fishes so that management decisions can be better based on evidence rather than judgement or extrapolation. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献