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261.
A Cu36Zr48Al8Ag8 alloy rod with a diameter of 10 mm was fabricated using a copper-mould suction casting method. Structural characterization revealed that the rod has different microstructures along the casting direction, including a complete amorphous structure and an amorphous/crystalline composite structure with different amount of B2 CuZr phase. Nanoindentation tests showed that the hardness and the elastic modulus of the crystalline phase are lower than those of the amorphous matrix. The hardness and the elastic modulus of the amorphous matrix decrease with decreasing crystalline proportion of the alloy, while the Vickers hardness of the alloy increases with a reduction in the crystalline proportion. 相似文献
262.
Jiří Marek 《Studies in East European Thought》1977,17(1):63-80
History and the philosophy of science have played a very important role in dialectical materialism; their results have been destined to support the correctness of the ideas of Marxist philosophers, especially in their application in historical materialism.From this point of view, the circumstances of the origin of the works of the Marxist classics cannot be neglected: Engels wrote hisDialectics in Nature in the period of classical physics, and Lenin published hisMaterialism and Empirio-Criticism at the beginning of the 20th century when our modern physics first began: shortly before the publication of Lenin's book, Röntgen and Becquerel discovered new kinds of radiation, Balmer published his ideas concerning the regularity of the hydrogen spectrum, Plank wrote his first articles about the elementary quantum and Einstein published his three famous articles (1905).During this period, physicists themselves did not understand their results, so important for the further development of physics. In this atmosphere of uncertainty, Lenin — a lawyer and politician — undertook his attempt to criticise the ideas of physicists.We trace one misinterpretation by Lenin of these ideas from books by Mach and Helmholtz. 相似文献
263.
攻击性儿童的P300事件相关电位研究 总被引:1,自引:0,他引:1
运用听觉P300任务对攻击性儿童(17人,其中16名男孩,1名女孩)与对照组的正常儿童( 人数与性别分布同攻击组)的事件相关电位(ERP)进行比较,发现攻击性儿童P30 0的潜伏期较长,波幅尤其是额部波幅较小,表明攻击性个体存在认知加工缺陷,特别是选择性注意与调控机能缺陷.研究结果同时表明P300可以作为鉴别攻击性个体的一个可靠指标. 相似文献
264.
Development in any domain is often characterized by increasingly abstract representations. Recent evidence in the domain of shape recognition provides one example; between 18 and 24 months children appear to build increasingly abstract representations of object shape [Smith, L. B. (2003). Learning to recognize objects. Psychological Science, 14, 244-250]. Abstraction is in part simplification because it requires the removal of irrelevant information. At the same time, part of generalization is ignoring irrelevant differences. The resulting prediction is this: simplification may enable generalization. Four experiments asked whether simple training instances could shortcut the process of abstraction and directly promote appropriate generalization. Toddlers were taught novel object categories with either simple or complex training exemplars. We found that children who learned with simple objects were able to generalize according to shape similarity, typically relevant for early object categories, better than those who learned with complex objects. Abstraction is the product of learning; using simplified - already abstracted instances - can short-cut that learning, leading to robust generalization. 相似文献
265.
266.
Psychometrika - Extended redundancy analysis (ERA), a generalized version of redundancy analysis (RA), has been proposed as a useful method for examining interrelationships among multiple sets of... 相似文献
267.
268.
临床医学生人文教育不能模糊医学人文知识和医学人文精神两个不同的概念,需要科学精神和人文精神的辩证统一。临床医学人文教育理论与实践的分离,临床医学人文教学与临床医学专业教学的分离,临床医学人文教育目标、实现途径和评价体系的不确定性,使临床医学生难敌市场经济功利性的负面导引,医学模式的转换在教育层面受阻。 相似文献
269.
The practice of learning from multiple instances seems to allow children to learn about relational structure. The experiments reported here focused on two issues regarding relational learning from multiple instances: (a) what kind of perceptual situations foster such learning and (b) how particular object properties, such as complexity and similarity, interact with relational learning. Two kinds of perceptual situations were of interest here: simultaneous view, where instances are viewed at once, and sequential view, where instances are viewed one at a time (one right after the other). We examined the influence of particular perceptual situations and object properties using two tests of relational reasoning: a common match-to-sample task, where new instances are compared with a common sample, and a variable match-to-sample task, where new instances are compared with a sample that varies on each trial. Experiments 1 and 2 indicate that simultaneous presentation of even highly dissimilar instances, one simple and one complex, effectively connects them together and improves relational generalization in both match-to-sample tasks. Experiment 3 shows that simple samples are more effective than complex ones in the common match-to-sample task. However, when one instance is not used a common sample and various pairs of instances are simply compared, as in Experiment 4, simple and rich instances are equally effective at promoting relational learning. These results bear on our understanding of how children connect instances and how those initial connections affect learning and generalization. 相似文献
270.
The ameliorating effect of oroxylin A on scopolamine-induced memory impairment in mice 总被引:2,自引:0,他引:2
Kim DH Jeon SJ Son KH Jung JW Lee S Yoon BH Lee JJ Cho YW Cheong JH Ko KH Ryu JH 《Neurobiology of learning and memory》2007,87(4):536-546
Oroxylin A is a flavonoid and was originally isolated from the root of Scutellaria baicalensis Georgi., one of the most important medicinal herbs in traditional Chinese medicine. The aim of this study was to investigate the ameliorating effects of oroxylin A on memory impairment using the passive avoidance test, the Y-maze test, and the Morris water maze test in mice. Drug-induced amnesia was induced by administering scopolamine (1 mg/kg, i.p.) or diazepam (1 mg/kg, i.p.). Oroxylin A (5 mg/kg) significantly reversed cognitive impairments in mice by passive avoidance and the Y-maze testing (P<.05). Oroxylin A also improved escape latencies in training trials and increased swimming times and distances within the target zone of the Morris water maze (P<.05). Moreover, the ameliorating effects of oroxylin A were antagonized by both muscimol and diazepam (0.25 mg/kg, i.p., respectively), which are GABA(A) receptor agonists. Furthermore, oroxylin A (100 microM) was found to inhibit GABA-induced inward Cl(-) current in a single cortical neuron. These results suggest that oroxylin A may be useful for the treatment of cognitive impairments induced by cholinergic dysfunction via the GABAergic nervous system. 相似文献