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关于电功及电功率的教材,在与学习苏联电力化的物理原理有关的知识范围中,占有重要的地位。这些概念的理解、关于它们的量度单位的清楚的观念以及进行有关的简单计算的技能应该是综合技术教育的必要组成部分。可惜,在七年级的物理教科书中,这个学习材料的叙述是形式的、干燥的、很简单的,并且从 相似文献
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利用直接模拟蒙特卡洛方法(DSMC) ,模拟了磁控溅射气体团簇源中Cu+ (Cu-)的含量比例不同的条件下,Cu团簇的尺寸分布。模拟结果表明:随着含量比例的增加,团簇的尺寸分布变窄了,不带电的团簇的比例增加,不带电的铜团簇分布的最大值减小,相应的带正电荷和带负电荷团簇的比例减小;相同的含量比例下,带正电的团簇的尺寸分布与带负电荷的团簇的尺寸分布基本相同;初始Cu- 比Cu+ 的含量比例大时,输出的主要是带负电荷的团簇,带正电荷和不带电的团簇占很小的比例;Cu-含量比例的增加,负Cu团簇的尺寸分布减小。 相似文献
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利用直接模拟蒙特卡洛方法(DSMC) ,模拟了磁控溅射气体团簇源中Cu+ (Cu-)的含量比例不同的条件下,Cu团簇的尺寸分布。模拟结果表明:随着含量比例的增加,团簇的尺寸分布变窄了,不带电的团簇的比例增加,不带电的铜团簇分布的最大值减小,相应的带正电荷和带负电荷团簇的比例减小;相同的含量比例下,带正电的团簇的尺寸分布与带负电荷的团簇的尺寸分布基本相同;初始Cu- 比Cu+ 的含量比例大时,输出的主要是带负电荷的团簇,带正电荷和不带电的团簇占很小的比例;Cu-含量比例的增加,负Cu团簇的尺寸分布减小。 相似文献
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来自双中子星并合的引力波事件GW170817和伴随的电磁波段的观测,是天文学研究上的一个重要突破。它不仅带给人类史无前例的关于中子星、伽马暴、千新星的知识,也提供了一个检验强场引力的极端天体实验室。爱因斯坦的广义相对论在不同的方面得到了全新的检验,包括引力的速度、引力子的质量、时空的对称性、引力波的辐射和偏振等。这些检验在更高的精度与更广的视角上肯定了广义相对论的预言。 相似文献
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寂静地震与地震预测的物理问题 总被引:4,自引:0,他引:4
寂静地震是指发生了缓慢的位错、但几乎不辐射地震波的“地震” .在目前的地震预测的物理学研究中 ,通常是通过计算历史上曾经发生过的地震所引起的应力变化 ,或者通过研究地震活动的统计性质或“图像动力学” ,来推测一个断层带上发生地震的危险性 .寂静地震的信息的缺失 ,形成了地震预测的物理学研究中的一个很大的“盲区” ,而在相当程度上 ,解决地震预测的物理问题的主要困难和可能的突破的希望 ,也许就在于此 .寂静地震的研究目前还很不深入 .关于寂静地震的性质 ,文章作者提出两个猜想 :(1)寂静地震的频度 ,满足类似于GR定律的幂律分布 ;(2 )最大的寂静地震的地震矩 ,与“可见”的最大地震的地震矩相当 . 相似文献
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用于高速数据通信的梯度塑料光纤 总被引:1,自引:0,他引:1
概述了梯度塑料光纤的开发历史和现状。从应用于高速数据通信的角度 ,介绍了聚甲基丙烯酸甲酯(PMMA)、全氘化和全氟化梯度塑料光纤的损耗、带宽、稳定性和寿命。详细介绍了梯度塑料光纤的损耗光谱和损耗机制 ,介绍了制作梯度塑料光纤的界面凝胶聚合技术和两种扩散法 ,分析了梯度塑料光纤的制作方法同折射率剖面和带宽的关系 ,讨论了梯度塑料光纤的稳定性同掺杂物质的关系。同时介绍了高稳定性梯度塑料光纤的研究进展及今后的发展动向 相似文献
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采用离子交换法制备了Rb:KTP晶体光波导,在不同波长的耦合光下测量了TE和TM偏振波导模式的有效折射率,拟合了波导层折射率的余误差函数分布,证明了波导折射率增量的各向异性,给出了其色散关系;最后计算并讨论了Rb:KTP波导的扩散特性。 相似文献
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The results of studying the magnetomechanical effects in classical superconductors are analyzed. The energy losses are determined,
and a number of macroscopic parameters are calculated using a developed model. The studies of superconductors by the method
of rotation of a body suspended without contact are described. The results obtained are analyzed, and the values of some parameters
are determined. 相似文献
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亲水性材料固相萃取-紫外导数光谱法检测血中茚满二酮灯抗凝 … 总被引:6,自引:1,他引:5
本文报导了血中茚满二酮类抗凝血杀鼠剂敌鼠、氯敌鼠、杀鼠酮的亲水性材料固相萃取-紫外导数光谱检测法。血样用pH5缓冲液等体积稀释后加于西雷脱硅藻土柱上,柱用乙酸乙 酯洗脱,将洗脱液挥发干净,剩余物用pH10缓冲液溶解,测定所得溶液的二阶导数光谱进行定性和定量分析。三种杀鼠剂以10mg/L的量加于空白血中测得萃取率为85%以上,血中三种杀鼠剂的检出限低于2mg/L。萃取中亲水性硅藻土可用硅胶和氧化铝代替, 相似文献
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A.-S. F. Obada G. M. Abd Al-Kader 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(1):189-198
The nonlinear extensions of the single-mode squeezed vacuum and
squeezed coherent states are studied. We have constructed the
nonlinear squeezed states (NLSS's) realization of
SU(1,1) Lie algebra. Two cases of this realization are
considered for unitary and non-unitary deformation operator
function. The nonlinear squeezed coherent states (NLSCS's)
are defined and special cases of these states are obtained.
Some nonclassical properties of these states are discussed. The
s-parameterized characteristic function and various moments are
calculated. The Glauber second-order coherence function is
calculated. The squeezing properties of the NLSCS's are studied.
Analytical and numerical results for the quadrature component
distributions for the NLSCS's are presented. A generation scheme for
NLSCS's using the trapped ions centre-of-mass motion approach is
proposed. 相似文献
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The spin-wave excitations in anisotropic Kondo lattice model are studied using the spin Green's function. Both the ferromagnetic and antiferromagnetic cases are considered. The equations to determine the spectrum of low-energy excitations are given. The anisotropy gaps are obtained, and the long-wavelength and strong-coupling limits are analyzed. 相似文献
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Rodney Loudon 《物理学进展》2013,62(66):243-280
The contributions of magnons to the optical properties of antiferromagnets having the rutile structure are discussed. The properties considered are electric-dipole active two-magnon absorption in the infra-red, and magnon sidebands on sharp-line exciton transitions in the visible. The discussion is based on a thorough treatment of the properties of excitons and magnons in the antiferromagnetically ordered state. The site-group and space-group symmetries of the magnetic excitations are derived and the selection rules for electric and magnetic dipole transitions are determined. The occurrence of magnetic Davydov splittings of the excitons is investigated, and their symmetry properties throughout the Brillouin zone are derived. The functional dependences of exciton energy on wave vector are calculated. Applications of the theory are made to experimental results on excitons and magnons in MnF2, FeF2 and CoF2. The possible mechanisms for two-magnon and magnon-sideband absorption are discussed, and the influence of crystal symmetry on these mechanisms is described. The two-magnon state responsible for electric-dipole absorption is identified and selection rules for electric-dipole activity are presented. A spin Hamiltonian for the two-magnon process is set up and used to derive expressions for absorption coefficients for electric vector parallel and perpendicular to the crystal c-axis. Comparison with experiment for MnF2 yields numerical values for the parameters of the basic coupling mechanism. The exciton-magnon states which give rise to magnon-sideband absorption are explicitly constructed and electric-dipole selection rules are derived for all possible types of sideband. Spin Hamiltonians for the various magnonsideband absorption processes are presented and used to derive expressions for sideband shapes. The results are applied to the experimental spectra for MnF2 and FeF2 and the sideband shapes in MnF2 are calculated numerically. The sideband shapes observable in emission spectra are also briefly discussed. 相似文献
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The dynamic characteristics of one blade, two discs and one shrouded, bladed disc, having 87 blades, are predicted by the application of the finite element method of analysis. The discs are modelled by using both annular and sector elements. The blades are modelled by means of shell elements. The shrouds are represented by both lumped masses and straight beam elements. The predicted frequencies are compared with experimental results. 相似文献