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马赫反射效应在炸药爆轰合成金刚石中的应用 被引量:6
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作者 恽寿榕 陈权 +1 位作者 马峰 陈鹏万 《高压物理学报》 CAS CSCD 北大核心 1997年第2期110-116,共7页
在爆轰法合成超细金刚石中利用马赫效应提高金刚石得率。用Whitham方法计算马赫杆上的爆轰参数。实验采用中间为TNT药柱,外边包裹TNT/RDX30/70的装药,在爆炸罐氮气介质中爆炸,超细金刚石得率为6%,包裹盐后... 在爆轰法合成超细金刚石中利用马赫效应提高金刚石得率。用Whitham方法计算马赫杆上的爆轰参数。实验采用中间为TNT药柱,外边包裹TNT/RDX30/70的装药,在爆炸罐氮气介质中爆炸,超细金刚石得率为6%,包裹盐后得率超过10%。 展开更多
关键词 马赫效应 超细金刚石 爆轰 金刚石合成 炸药
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装药及外界保护介质对炸药爆轰合成超微金刚石的影响 被引量:5
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作者 马峰 恽寿榕 +1 位作者 陈权 陈鹏万 《爆炸与冲击》 EI CAS CSCD 北大核心 1998年第4期289-295,共7页
研究了不同保护介质对超微金刚石(UFD)生成的影响,认为爆轰产物与外部介质间的传热速度对UFD得率影响很大;外部保护介质在爆轰产物膨胀阶段的保压作用在UFD合成过程中有重要作用。实验结果指出,要提高UFD得率,装药应... 研究了不同保护介质对超微金刚石(UFD)生成的影响,认为爆轰产物与外部介质间的传热速度对UFD得率影响很大;外部保护介质在爆轰产物膨胀阶段的保压作用在UFD合成过程中有重要作用。实验结果指出,要提高UFD得率,装药应存在一个最佳直径。用水和冰作为保护介质可使UFD得率超过10%,比利用马赫效应装药更适用于实际生产。 展开更多
关键词 超微金刚石 爆轰 马赫效应 金刚石合成 装药
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移动简谐力作用下三维多孔饱和半空间的动力问题 被引量:2
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作者 刘琦 金波 《固体力学学报》 CAS CSCD 北大核心 2008年第1期98-103,共6页
研究了移动荷载作用下多孔饱和地基的动力问题.应用Fourier变换求解该问题的控制偏微分方程,考虑了荷载的移动速度及振动频率对多孔饱和地基动力响应的影响,重点研究了移动速度达地基表面波速时多孔饱和半空间的振动问题(马赫效应),并... 研究了移动荷载作用下多孔饱和地基的动力问题.应用Fourier变换求解该问题的控制偏微分方程,考虑了荷载的移动速度及振动频率对多孔饱和地基动力响应的影响,重点研究了移动速度达地基表面波速时多孔饱和半空间的振动问题(马赫效应),并与相应的弹性介质的解答进行了比较.结果显示当移动速度与多孔饱和半空间的表面波速相近时,地基会产生很大的振动;当移动速度大于表面波速时,多孔饱和半空间的动力响应与弹性半空间的动力响应有较大的差别. 展开更多
关键词 多孔饱和地基 Biot动力方程 移动荷载 地基表面波速 马赫效应
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Mass of the Universe and the Redshift 被引量:1
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作者 Rajendra P. Gupta 《International Journal of Astronomy and Astrophysics》 2018年第1期68-78,共11页
Cosmological redshift is commonly attributed to the continuous expansion of the universe starting from the Big-Bang. However, expansion models require simplifying assumptions and multiple parameters to get acceptable ... Cosmological redshift is commonly attributed to the continuous expansion of the universe starting from the Big-Bang. However, expansion models require simplifying assumptions and multiple parameters to get acceptable fit to the observed data. Here we consider the redshift to be a hybrid of two effects: recession of distant galaxies due to expansion of the universe, and resistance to light propagation due to cosmic drag. The weight factor determining the contribution of the two effects is the only parameter that is needed to fit the observed data. The cosmic drag considered phenomenologically yields mass of the universe &asymp;?2 × 1053 kg. This implicitly suggests that the mass of the whole universe is causing the cosmic drag. The databases of extragalactic objects containing redshift z and distance modulus &mu;of galaxies up to z = 8.26 resulted in an excellent fit to the model. Also, the weight factor wD for expansion effect contribution to &mu;obtained from the data sets containing progressively higher values of &mu;?can be nicely fitted with . 展开更多
关键词 REDSHIFT EXPANDING UNIVERSE mach effect COSMIC Drag COSMOLOGICAL Constant
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Mach Effect of Oblique Nonlinear Irregular Waves Interacting with Vertical Walls 被引量:1
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作者 冯卫兵 潘丽红 洪广文 《海洋工程:英文版》 EI 2004年第2期299-306,共8页
Based on Hong's theory, previous random models, and a generalized expression suitable for FFT calculation, the interaction between irregular waves and vertical walls is numerically simulated. The results of simu... Based on Hong's theory, previous random models, and a generalized expression suitable for FFT calculation, the interaction between irregular waves and vertical walls is numerically simulated. The results of simulation demonstrate that the wave energy changes with the incidence angle and the distance from the wall. Particularly, the Mach effect and the combined wave spectrum characteristics are analyzed in detail, which are significant in both theory and practice. 展开更多
关键词 mach effect nonlinear wave interaction of waves
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海洋内孤立波斜相互作用的Mach效应特性实验
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作者 王欣隆 魏岗 +2 位作者 杜辉 谷梦梦 王彩霞 《科学通报》 EI CAS CSCD 北大核心 2016年第4期529-535,共7页
当海洋工程结构物或水下航行器在海洋中遭遇异常大振幅内波时可造成损害甚至失事,海洋内孤立波斜相互作用的Mach效应是一种特殊海洋现象,也是异常大振幅内孤立波的重要成因.为了在实验室模拟具有海洋跃层环境中的内孤立波斜相互作用并控... 当海洋工程结构物或水下航行器在海洋中遭遇异常大振幅内波时可造成损害甚至失事,海洋内孤立波斜相互作用的Mach效应是一种特殊海洋现象,也是异常大振幅内孤立波的重要成因.为了在实验室模拟具有海洋跃层环境中的内孤立波斜相互作用并控制Mach效应的产生,首先将两只直立无底圆柱筒放置在淡/盐水分布的两层流体环境中,淡/盐水混合区模拟海洋密度跃层,保持筒底与筒外水体的交换,以方便形成筒内外混合区的高度差;再将两柱筒平稳迅速移出,利用柱筒内外淡/盐水混合区高度差的重力塌陷扰动形成两列内孤立波,其在交汇区发生斜相互作用,并借助高清图像处理技术结合几何射线方法完成测量.实验结果表明:两列内孤立波斜相互作用性质取决于分层环境、两柱筒之间距离以及两列内孤立波的波幅和相位,上述方法可有效控制分层流实验水槽中Mach效应的产生.进一步分析表明:两列内孤立波相互作用的Mach效应将导致波幅显著增强,传播速度明显增大,且传播方向受两者振幅大小的控制,振幅相差越大所产生Mach效应的临界夹角越大.此外,通过内孤立波斜相互作用的Mach效应实验结果与Kd V,BO和MCC三种理论模型的比较,实验验证了Mach效应对非线性理论模型的适应性. 展开更多
关键词 分层流 内孤立波 斜相互作用 mach效应 水槽实验
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Theory of a Mach Effect Thruster II
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作者 Heidi Fearn Nolan van Rossum +1 位作者 Keith Wanser James F. Woodward 《Journal of Modern Physics》 2015年第13期1868-1880,共13页
According to Einstein, General Relativity contains the essence of Mach’s ideas. Mach’s principle can be summarized by stating that the inertia of a body is determined by the rest of the mass-energy content of the un... According to Einstein, General Relativity contains the essence of Mach’s ideas. Mach’s principle can be summarized by stating that the inertia of a body is determined by the rest of the mass-energy content of the universe. Inertia here arises from mass-energy there. The latter, was a statement made by John Wheeler in his 1995 book, Gravitation and Inertia, coauthored by Ciufolini. Einstein believed that to be fully Machian, gravity would need a radiative component, an action-at-a-distance character, so that gravitational influences on a body from far away could be felt immediately. In 1960’s, Hoyle and Narlikar (HN) developed such a theory which was a gravitational version of the Absorber theory derived by Wheeler-Feynman for classical electrodynamics and later expanded upon by Davies and Narlikar for quantum electrodynamics. The HN-field equation has the same type of mass fluctuation terms as in the Woodward Mach effect thruster theory. The force equation, used to predict the thrust in our device, can be derived from the mass fluctuation. We outline a new method for deriving the force equation. We present new experimental tests of the thruster to show that the thrust seen in our device is not due to either heating or Dean Drive effects. Successful replications have been performed by groups in Austria and Canada, but their work is still pending in the peer review literature. 展开更多
关键词 mach effect Drive Transient Mass FLUCTUATIONS mach’s Principle Action at a Distance Advanced WAVES Event HORIZON
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Theory of a Mach Effect Thruster I
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作者 Heidi Fearn Adam Zachar +1 位作者 Keith Wanser James Woodward 《Journal of Modern Physics》 2015年第11期1510-1525,共16页
The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass—energy fluctuations, [1]-[3]. Mach’s principle is ... The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produce thrust in an accelerating material which is undergoing mass—energy fluctuations, [1]-[3]. Mach’s principle is a statement that the inertia of a body is the result of the gravitational interaction of the body with the rest of the mass-energy in the universe. The MET device uses electric power of 100 - 200 Watts to operate. The thrust produced by these devices, at the present time, are small on the order of a few micro-Newtons. We give a physical description of the MET device and apparatus for measuring thrusts. Next we explain the basic theory behind the device which involves gravitation and advanced waves to incorporate instantaneous action at a distance. The advanced wave concept is a means to conserve momentum of the system with the universe. There is no momentun violation in this theory. We briefly review absorber theory by summarizing Dirac, Wheeler-Feynman and Hoyle-Narlikar (HN). We show how Woodward’s mass fluctuation formula can be derived from first principles using the HN-theory which is a fully Machian version of Einstein’s relativity. HN-theory reduces to Einstein’s field equations in the limit of smooth fluid distribution of matter and a simple coordinate transformation. 展开更多
关键词 mach effect Drive Transient Mass Fluctuations Weak Field Limit GRAVITATION Modified (PPN) Parameterized Post NEWTONIAN Approximation Linearized EINSTEIN Equations Gravitoelectromagnetism
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近空间高超声速气动力数据天地换算研究 被引量:6
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作者 龚安龙 解静 +3 位作者 刘晓文 刘周 杨云军 周伟江 《工程力学》 EI CSCD 北大核心 2017年第10期229-238,共10页
该文针对高升阻比面对称飞行器近空间高超声速飞行环境,考虑马赫数效应、粘性干扰效应和真实气体效应等多种复杂气动效应对飞行器气动力数据的影响,采用CFD数值模拟技术和气动数据相关性理论分析方法,建立了基于地面风洞试验外推获取实... 该文针对高升阻比面对称飞行器近空间高超声速飞行环境,考虑马赫数效应、粘性干扰效应和真实气体效应等多种复杂气动效应对飞行器气动力数据的影响,采用CFD数值模拟技术和气动数据相关性理论分析方法,建立了基于地面风洞试验外推获取实际飞行状态下气动力数据的天地换算方法;并采用CFD技术对气动力数据天地换算的精确性进行了验证。 展开更多
关键词 高超声速 马赫数效应 粘性干扰效应 真实气体效应 气动力数据 天地换算
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视知觉与绘画二议 被引量:1
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作者 林凤生 《自然杂志》 北大核心 2013年第4期307-312,共6页
在欣赏绘画时,观众的感受是一个综合了生理学、心理学等多方面的复杂过程,科学家对此已经关注了多年,并取得了引人注目的研究成果。笔者介绍了马赫带效应、眼球运动和浦肯雅现象等视觉生理特点对绘画观赏的影响。
关键词 蒙娜丽莎微笑 眼球运动 浦肯雅现象 空间频率 马赫带效应
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