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青藏高原山地系统动力学模型研究 被引量:2
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作者 毕思文 《山地学报》 CSCD 2001年第3期193-200,共8页
以地球系统科学为研究思路 ,研究了青藏高原山地系统各圈层相互作用的统一构造动力模型、力学模型和数值模拟等。关于青藏高原山地系统动力学特征 ,主要研究高原山地系统现今构造应力场演化特征和高原山地系统统一构造动力模型 ,认为均... 以地球系统科学为研究思路 ,研究了青藏高原山地系统各圈层相互作用的统一构造动力模型、力学模型和数值模拟等。关于青藏高原山地系统动力学特征 ,主要研究高原山地系统现今构造应力场演化特征和高原山地系统统一构造动力模型 ,认为均起源于喜马拉雅运动期印度 -欧亚板块碰撞引发的统一的板块汇聚动力体系和各圈层与之相应的一系列运动学和动力学过程。关于青藏高原山地各圈层力学系统描述 ,主要把山地各圈层块体质点作为一个力学系统来描述 ,求解速度向量、位移向量、密度场、温度场、应力张量等物理量和状态空间 ,最后求解运动方程。关于青藏高原山地系统的非稳定性问题 ,将给定的载荷历史分成许多小的增量步 ,对每一个增量步求解一个非线性边值问题。使用失稳量准则判断山地系统的稳定性。关于青藏高原山地各圈层多体系统力学描述 ,青藏高原是由多圈层多块体不同物质结构组成的 ,皆可用若干塑性、流变体、流体和弹性组成的系统模型予以有效地描述。主要研究内容有 :高原山地系统碰撞隆升的分类和现象、山地主动碰撞构造体特性和山地被动碰撞体 (靶体 )特性等力学模型。文中初步分析和推断了演变的历史与现状 。 展开更多
关键词 青藏高原 山地系统 各圈层统一相互作用 动力学模型
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超弦、M理论简介
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作者 陆继宗 《自然杂志》 北大核心 2001年第2期67-75,共9页
关键词 基本粒子 基本相互作用 统一相互作用 规范理论 超对策 超弦 M理论 粒子物理学 夸克 量子理论 微观物质
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Unified Theory of Fundamental Interactions 被引量:1
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作者 WUNing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2003年第5期561-568,共8页
Based on local gauge invariance, four different kinds of fundamental interactions in nature are unified in a theory which has Gravitational Gauge Group gauge symmetry. In this approach, gravitational field, like elec... Based on local gauge invariance, four different kinds of fundamental interactions in nature are unified in a theory which has Gravitational Gauge Group gauge symmetry. In this approach, gravitational field, like electromagnetic field, intermediate gauge field, and gluon field, is represented by gauge potential. Four kinds of fundamental interactions are formulated in the similar manner, and therefore can be unified in a direct or semi-direct product group. The model discussed in this paper is a renormalizable quantum model and can be regarded as an extension of the standard model to gravitational interactions, so it can be used to study quantum effects of gravitational interactions. 展开更多
关键词 unified field theories gauge field quantum gravity
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自然科学规律的探索与人类社会的进步
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作者 卢建新 《科技与法律》 2017年第2期36-40,共5页
基础研究是原始创新的源泉,没有基础和前沿领域的原始创新,科技创新就没有了根基。科学技术当前的地位和作用更为凸显,科学技术的发展从来没有像今天这样深刻地影响人类社会的方方面面,深刻地影响着人们的思想观念和生活方式,促进着人... 基础研究是原始创新的源泉,没有基础和前沿领域的原始创新,科技创新就没有了根基。科学技术当前的地位和作用更为凸显,科学技术的发展从来没有像今天这样深刻地影响人类社会的方方面面,深刻地影响着人们的思想观念和生活方式,促进着人类社会的进步。本文将从科学发展的简单历史角度阐述自然科学规律的探索与科学技术的发展以及与促进人类社会进步的关联。 展开更多
关键词 基础研究 相互作用及其统一 科学技术 生产力 人类社会
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Dilaton Black Hole Tunneling Radiation in de Sitter Universe
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作者 LI Gu-Qiang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第3期453-454,共2页
The Hawking radiation via tunneling from the dilaton black hole in de Sitter universe is investigated using Parikh Wilczek's method. We show that if the self-gravitational interaction and energy conservation are take... The Hawking radiation via tunneling from the dilaton black hole in de Sitter universe is investigated using Parikh Wilczek's method. We show that if the self-gravitational interaction and energy conservation are taken into account, the modified radiation spectrum deviates from exact thermal spectrum and satisfies the unitary theory. 展开更多
关键词 tunneling radiation de Sitter universe dilaton black hole
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Geometry Is the Common Thread in a Grand Unified Field Theory
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作者 Olaniyi S. Maliki 《Journal of Physical Science and Application》 2017年第4期38-46,共9页
The consequence of the wave-particle duality is a pointer to the fact that everything in the universe, including light and gravity, can be described in terms of particles. These particles have a property called spin. ... The consequence of the wave-particle duality is a pointer to the fact that everything in the universe, including light and gravity, can be described in terms of particles. These particles have a property called spin. What the spin of a particle really tells us is what the particle looks like from different directions, in other words it is nothing more than a geometrical property. The motivation for this work stems from the fact that geometry has always played a fundamental role in physics, macroscopic and microscopic, relativistic and non-relativistic. Our belief is that if a GUT (Grand Unified Theory) is to be established at all, then geometry must be the common thread connecting all the different aspects of the already known theories. We propose a new way to visualize the concept of four-dimensional space-time in simple geometrical terms. It is observed that our time frame becomes curved, just as the space-frame, in the presence of a massive gravitating body. Specifically, in the event horizon of a black hole, where time seems to grind to a halt for external observers, the time frame appears to curve in on itself, forming an imaginary loop. This results in extreme time dilation, due to the strong gravitational field. Finally we adopt a descriptive view of a GUT called Quantum Necklace GUT which attempts to connect gravity together the other three fundamental forces of nature, namely the strong, weak and electromagnetic interactions. 展开更多
关键词 GUT GEOMETRY SPACE-TIME spin RELATIVITY Einstein field equations.
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Cyanido-bridged one-dimensional systems assembled from [Re~ⅣCl_4(CN)_2]_(2-) and [M~Ⅱ(cyclam)]^(2+) (M=Ni,Cu) precursors
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作者 BHOWMICK Indrani HARRIS T. David +4 位作者 DECHAMBENOIT Pierre HILLARD Elizabeth A. PICHON Cline JEON Ie-Rang CLéRAC Rodolphe 《Science China Chemistry》 SCIE EI CAS 2012年第6期1004-1011,1192-1197,共8页
Three new cyanido-bridged heterometallic ReIVNin and ReIVCu one-dimensional systems were synthesized and extensively characterized both structurally and magnetically. Single-crystal X-ray diffraction analysis revealed... Three new cyanido-bridged heterometallic ReIVNin and ReIVCu one-dimensional systems were synthesized and extensively characterized both structurally and magnetically. Single-crystal X-ray diffraction analysis revealed that these compounds display a common topology, with chains composed of alternating [RetVc14(CN)2]2- and [Mn(cyclam)]2+ (M = Ni in 1, Cu in 2) or [Cull(N,N'-dimethylcyclam)]2+ (in 3) building units. Two different chain orientations with a tilt angle of ca. 51° to 55° are present in the crystal packing of these compounds. The magnetic susceptibility measurements suggest the presence of intrachain ferromagnetic interactions between the S = 3/2 ReTM centers and the 3d metal ions: S = 1 Ni1I or S = 1/2 CuII. At low temperature, a three-dimensional ordered magnetic phase induced by interchain antiferromagnetic interactions (antiferromagnetic for 1 and 2; canted antiferromagnetic for 3) is detected for the three compounds. 展开更多
关键词 molecular magnets cyanido-based materials crystal structure magnetic properties
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环环相扣的英语学习策略
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作者 代金红 《科学中国人》 2014年第09S期247-247,共1页
在英语学习中,预习、精读、整理、训练、回忆五个步骤,是相互联系,相互作用的统一体。“忆”、“读”和“理”是理解消化课堂教学内容的过程,“练”是运用知识,培养技能的过程,五者缺一不可。一个目标:切实提英语学习质量。
关键词 预习、精读、整理、训练、回忆五个步骤 相互联系 相互作用统一
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