共查询到20条相似文献，搜索用时 125 毫秒
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刘谋辉 《湖南科技学院学报》2004,25(6):75-79
在现代物理学中,黑洞是最错综复杂的物体之一.它们为美星体和其他活动星系核提供能量,也有助于透彻地理解量子引力.我们回顾一下黑洞的观测上的证据并简单地讨论它们的一些特性,也阐述了一些近年来涉及宇宙监督和黑洞熵统计起源的进展情况. 相似文献
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黑洞,是天体物理学中的概念。在宇宙中,一些大质量的物体在发生坍塌之后,会形成一个致密的点,由于它的质量非常大,所以产生的引力也非常大,大到光线进去之后也无法逃出来,于是就形成了一个黑洞。而且不断被吞噬进去的物质和能量又反过来成为黑洞的一部分,使得黑洞产生更大的吸引力。天体物理学研究黑洞得出的结论是,黑洞有超强大的吞噬能力,另外一方面黑洞还具有复制和自我强化的能力。 相似文献
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蒋健 《语文世界(高中版)》2018,(Z1)
正同学们,黑洞这个神秘天体,就像魔咒一般深深地吸引着我们。多年来,人类对黑洞的探索从未停止,我国的科学家也对黑洞进行了深入的研究和不懈的探索。(小好奇)为了研究黑洞、中子星等高能致密天体的基本物理性质以及它们对周围时空的影响,中国科学院高能物理研究所和航天科技集团五院等单位研制了我国第一颗空间X射线天文卫星——HXMT卫星。 相似文献
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杨成全 《雁北师范学院学报》2000,(3)
该文讨论了变加速直线运动带电黑洞的霍金效应．给出了事件视界和相应的温度分析了一些特别有趣地情况．发现带电黑洞的霍金温度不仅依赖于时间,而且依赖于极角．当黑洞内外视界接触时,霍金温度为零．在某种条件下,黑洞视界与Rindler视界温度相等．零温黑洞与Rindler视界接触时．霍金温度为零． 相似文献
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近年来,社会资本理论已经成为社会学、政治学等学科所普遍关注的热点和前沿问题,社会资本概念也被广泛用来解释经济增长和社会发展。虽然社会资本具有强大的解释力,但是社会资本也有其固有的、自身无法解决的困境。本文拟就社会资本的解释力与困境做一些探讨,旨在使人们对社会资本有更加深刻的认识,以期能为以后的研究提供一定的参考。 相似文献
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刘尚励 《安徽教育学院学报》2005,23(6):40-42
霍金先生的关于宇宙的阐述给人们提供了许多激动人心的课题,然而作为科学家的大胆的预言忽视了哲学的关于绝对时空和相对时空及有限与无限的问题.导致了大爆炸与光锥理论之间的悖论. 相似文献
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Imagine waking up one day and finding yourself walking through a foggy green scene. As the scene clarifies, you see tall columns, trees. The trees have ridges, groves, and holes on their sides. Some are rough, others smooth. Getting closer, it's possible to smell differences between each of the trees. On the surface of the trees, insects are found, some hiding in holes and crevices, some on the surface. A bird alights halfway up a tree chasing some insects.Dennis W. Sunal and Cynthia Szymanski Sunal are Associate Professors at the University of Alabama in the area of Curriculum and Instruction. 相似文献
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One classical instructional effect of cognitive load theory (CLT) is the worked-example effect. Although the vast majority of studies have focused on well-structured and algorithmic sub-domains of mathematics or physics, more recent studies have also analyzed learning with examples from complex domains in which only heuristic solution strategies can be taught (e.g., troubleshooting, mathematical proving). Is learning by such examples also effective, and do the same instructional design principles apply? We discuss the main findings of an own research program and of related studies that addressed such questions. We found that CLT’s basic design principles also hold true for heuristic domains: Reduce extraneous load by employing examples, maximize germane load by fostering self-explanations, prevent cognitive overload by pretraining in the case of difficult learning materials, and by focusing attention on the most relevant aspects. Other typical CLT assumptions (e.g., better provide information for novice learners) were not confirmed in its generality. The present findings extend the applicability of CLT but also identify some potentially too simplistic assumptions. 相似文献
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非均衡理论在云南经济发展实践中的应用分析 总被引：1，自引：0，他引：1
本文简要阐述国内外主要的非均衡理论 ,分析云南省实行非均衡战略的实践效果 ,认为昆明核心区“增长极”的经济发展对全省经济发展有一定的带动和扩散作用。同时指出非均衡理论在实际运用中存在的问题。鉴于在新世纪中 ,“增长极”在经济发展中将依然发挥至关重要的作用 ,本文在前面分析的基础上 ,对云南省经济的发展提出了一些看法 相似文献
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Joanna Kozubska 《Action Learning: Research and Practice》2012,9(2):145-164
Here, we argue that action learning (AL) has been evolving into different variations, whose respective advocates appear to concentrate on one of the several components inherent in Revans’ formulation of AL as L?=?P?+?Q. They do this – sometimes inappropriately – to the virtual or relative exclusion of other aspects, and this has consequences for the outcomes and impact of the AL process. In an attempt to delimit the boundaries between various versions and indeed to identify what Johnson [2010. A framework for the ethical practice of action learning. Action Learning: Research and Practice 7, no. 3: 267–283] called ‘inauthentic’ AL, we have been developing our ideas for a scanning device or framework. We refer briefly to some of the theoretical underpinnings of this framework. We then introduce a fresh taxonomy to explain and illustrate features of five principal variations of emphasis in AL that we have identified. The aim of this framework is to help stakeholders to work towards selecting and co-creating the most appropriate variation of ‘authentic’ AL to suit their unique set of circumstances at any given time. We outline the likely outcomes of each respective variation if taken to extremes and conjecture about their implications. This taxonomy should also help one to reduce the mystique and confusion that often surround AL while acknowledging its complexity. We suggest that by taking advantage of insights provided by this framework, purchasers and potential AL set members in particular are more likely to participate in learning conversations that lead to more informed decisions and actions to address or adjust their respective interests and needs. In conclusion, we identify some areas for further research and development. 相似文献
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This paper responds to Wassell and LaVan’s paper on the transition from a preservice coteaching experience to independent
teaching as a beginning inservice teacher. Wassell and LaVan describe coteaching as an alternative to traditional teaching.
In our response, we argue that coteaching can also be applied alongside independent teaching in preservice courses, as opposed to an alternative to independent teaching, which has been shown to
alleviate some of the transition issues described by Wassell and LaVan. We then present a critical discussion of different
models and vocabularies of coteaching which apply in different sociocultural settings to expand the concept of coteaching.
We attempt to extend Wassell and LaVan’s use of Guba and Lincoln’s (Fourth generation evaluation, 1989) authenticity criteria
from the research methodology towards considering the criteria also as a framework for coteaching as practice for preservice
and cooperating teachers. Finally, we reflect on the role of critical ethnography in Wassell and LaVan’s study in terms of
the researchers’ intervention and whether improvements in the transition can be effectively introduced which do not require
such intervention. We conclude our discussion with some suggestions to take forward this important work.
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