共查询到20条相似文献,搜索用时 93 毫秒
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应用压缩角标方法所得到的三阶非线性系数的矩阵形式,首次给出了在单轴晶体事进行三次谐波实验时,各种相位匹配方式下,其三阶有效非线性系数的解析表达式。这些表达式对三次谐波实验具有指导意义。 相似文献
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光束抖动频谱遥感大气湍流外尺度的理论与实验 总被引:1,自引:1,他引:0
在微扰理论的基础上导出高斯光束相位归一化频谱的普遍表达式,进而法庭是归一化光束抖动频谱的普遍表达式以及准直光束和球面波光束在均匀光路条件下的分析表达式,计算表明这些频谱中存在一个与湍流外尺度,横截风速有确定关系的峰值频率。 相似文献
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双折射位相差的拟合表达式及其应用 总被引:1,自引:1,他引:0
探讨双折射晶体的o光和e光的位相差的表达式,对文献中常引用的表达式作近似展开,得到一个适用性的拟合表达式及其拟合系数与昌体或液晶双折射率之间的关系,并给出该表达式的简单应用。它可作为设计晶体旋转法测试液晶双折射和预角测试仪的原理。 相似文献
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本文应用鹤法得到光学涂层稳定性表达式。这些方法改进了涂层稳定条件的确定。应用这一方法,在掠角入射下对减反射涂层,全介质反射镜以及带通滤光片进行了计算。 相似文献
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本文考虑了分子晶体中内振子所有相邻能级之间存在的跃迁,给出了计算分子晶体中超声弛豫时间的新的表达式。对不同温度下萘单晶的超声吸收系数的计算表明,与Liebermann理论相比,我们得到的吸收随温度变化规律更符合实验结果。 相似文献
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In the Hellings-Nordtvedt theory, we obtain some expressions of energy
radiation and mass defect effect for a kind of the active galactic nuclei,
which is meaningful to calculating the energy radiation in the procession of
forming this kind of celestial bodies. This calculation can give some
interpretation for energy source of the jet from the active galactic nuclei. 相似文献
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从海量天体光谱数据中挖掘光谱数据特征和物理化学性质之间内在的、隐含的相关性,是人类探索天文规律的一种有效方法。利用基于约束FP树的关联规则挖掘方法作为天体光谱数据相关性分析手段,采用VC++和Oracle9i作为开发工具,设计与实现了天体光谱数据相关性分析系统,给出了其系统的软件体系结构和模块功能,并对光谱数据预处理、背景知识表示、CFP树构造、频繁模式提取及关联规则生成等关键技术以及关键模块的实现技术,进行了详细描述。系统运行结果表明,利用关联规则来描述、分析天体光谱数据特征和物理化学性质之间存在的相关性,是可行的和有价值的,从而为寻找天体规律提供了一种有效手段。 相似文献
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寻找特殊的、未知的天体是人类探索宇宙奥妙所追求的目标之一,天体光谱数据挖掘是实现该目标的一种有效方法。约束概念格是一种新的概念格结构,具有构造效率高、提取知识针对性和实用性强等特点。针对天体光谱数据在特征子空间中的局部偏离,采用VC++ 6.0和Oracle 9i作为开发工具,设计与实现了基于约束概念格的天体光谱局部离群数据挖掘系统,并对软件模块功能和体系结构,以及天体光谱数据预处理、约束概念格构造方法、基于链表结构的概念格构造、局部离群数据挖掘方法等关键技术进行了详细描述。运行结果表明,该系统实现天体光谱数据局部离群数据挖掘是可行的、有价值的,从而为寻找未知的、特殊的天体提供了一种新途径。 相似文献
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面向LAMOST的天体光谱离群数据挖掘系统研究 总被引:4,自引:3,他引:1
在宇宙中寻求未知天体是人类探索宇宙奥妙所追求的目标之一,离群数据挖掘是发现未知天体光谱数据的一种有效途径。文章首先以VC++和Oracle9i为开发工具,设计与实现了面向LAMOST的恒星光谱离群数据挖掘系统,并给出了其软件体系结构和模块功能。其次,对基于中值滤波器的恒星光谱数据预处理、基于距离的恒星光谱数据聚类、基于距离支持度的恒星光谱数据离群数据挖掘、基于主分量分析法PCA的恒星光谱数据离群数据的三维可视化等主要关键技术进行了详细描述。最后,基于SDSS恒星光谱数据的运行结果表明,利用该系统寻找天体光谱离群数据是可行的,从而为寻找未知的、特殊的天体光谱数据提供了一种新途径。 相似文献
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V. S. Imshennik 《Physics of Atomic Nuclei》2010,73(4):625-633
The standard problem of a radial motion of test particles in the stationary gravitational field of a spherically symmetric
celestial body is solved and is used to determine the time features of this motion. The problem is solved for the equations
of motion of general relativity (GR), and the time features are obtained in the post-Newtonian approximation, with linear
GR corrections proportional to r
g
/r and β
2 (in the solution being considered, they are of the same order of smallness) being taken rigorously into account. Total times
obtained by integrating the time differentials along the trajectories of motion are considered as the time features in question.
It is shown that, for any parameters of the motion, the proper time (which corresponds to watches comoving with a test particle)
exceeds the time of watches at rest (watches at the surface of the celestial body being considered). The mass and the radius
of the celestial body, as well as the initial velocity of the test particle, serve as arbitrary parameters of the motion.
The time difference indicated above implies a leading role of the gravitational redshift, which decreases somewhat because
of the opposite effect of the Doppler shift. The results are estimated quantitatively for the important (from the experimental
point of view) case of vertical flights of rockets starting from the Earth’s surface. In this case, the GR corrections, albeit
being extremely small (a few microseconds for several hours of the flight), aremeasurable with atomic (quantum) watches. 相似文献
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基于谱线检测的发射线星自动识别方法 总被引:1,自引:0,他引:1
针对我国即将建成的大型巡天项目(LAMOST),给出了一种基于谱线检测的发射线星自动识别方法.主要步骤:1)通过获取谱线特征匹配值进行恒星谱线整体估计;2)利用提取出的恒星谱线特征检测恒星的巴耳末(Balmer)线;3)对获取的特征匹配值采用阈值法,并结合恒星Balmer线的检测结果,进行发射线里判别.通过对SDSS DR4所有光谱进行识别,共获得了242条具有恒星发射线的特殊天体.根据星表查询结果,这些天体包括发射线星、激变变星和一些未知特殊天体等.大量真实光谱数据实验表明,本文方法可有效识别发射线星. 相似文献
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天文导航的航向误差与水平基准、载体位置的精度密切相关,以天文导航三角形的物理意义分析了天文导航测定航向的原理,推导了天文导航测定航向的精度与水平基准误差、载体地理位置误差等环节之间的公式,为天文导航仪器选择测量天体和提高精度提供了理论依据. 相似文献
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The post-Newtonian effects of the rotation of the central body on the variation of celestial orbital elements are studied according to the post-Newtonian metric theory. The variation of celestial orbital elements caused by the rotation of the central body in three gravitational theories of Einstein, Brans-Dicke and Nordtvedt is obtained by using the method of general perturbation. The resulting effects are the periodic variation of inclination, eccentricity and mean anomaly; the periodic and secular variation of longitudes of periastron and ascending node and mean longitudes of epoch, but the semimajor axis remains unperturbed (no variation). In addition, the obtained theoretical results are applied to the calculation of the post-Newtonian effect of the rotation of the sun on the variation of the orbital elements of planets in solar system. The numerical results are given in nble 1. Finally, the obtained results are discussed and compared with other theories. 相似文献
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V. P. Pavlyuchenko R. M. Martirosov N. M. Nikolskaya A. D. Erlykin 《Bulletin of the Russian Academy of Sciences: Physics》2017,81(4):413-415
Based on experimental data obtained by the GAMMA array for the knee energy region, an anomaly is found in the mass composition of primary cosmic rays arriving from the region of the Vela cluster. An original difference method is used that offers high sensitivity, protection against accidental experimental errors, and the ability to separate anomalies associated with the laboratory coordinate system from those in celestial coordinates. Allowing for the multiple scattering of charged particles in the galactic magnetic fields allows parts of the sky not directly visible from the array to be studied. 相似文献