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矢势的边值关系A1t=A2t是怎样得出来的 总被引:1,自引:1,他引:0
指出某些文献在推导矢势边值关系A1t=A2t时的不妥之处.示明得出这一边值关系的正确作法.论述了en·(×A2-×A1)=0与A1t=A2t两者之间的关系. 相似文献
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窄带噪声的调频也和纯音调频一样,能诱发豚鼠的皮层慢反应。反应的阈值(最小调频深度)即可作为对窄带噪声的音调辨别阈(△f)。豚鼠的△f与噪声通带的宽度B及中心频率f有关,△f与B的关系可表达为△f=AB~n。式中A为B=1Hz时的△f值,它与纯音的△f相近并随f而变;在f为1kHz及4kHz时n近似地为1/3。当f在125—8000Hz范围内、B/f比值不变时,△f/f基本上为一常数。这是在频率辨别研究领域内Weber定律的很好示例。△f-f-B三者的总关系在豚鼠可简单地用经验式△f=0.1f~(2/3)B~(1/3)表达。用此式算得的△f值与实验结果相当接近。 相似文献
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在有关教材中讨论过物体下落这类运动.如图1所示,物体受到动力F和阻力f,F不变(在下落运动中F=mg),f与速度v成正比,f=kv是变力. 相似文献
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Effect of annealing treatments on the microwave electromagnetic properties of amorphous FeCuNbSiB microwires
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The amorphous FeCuNbSiB microwires are fabricated by using the
melt extraction method and annealed separately at temperatures
T = 573, 673, 723 and 773K for 1h. The effect of annealing
treatment on the microwave electromagnetic properties of
FeCuNbSiB wires/wax composites has been investigated for the
first time. It is found that in a frequency range of
0.5--4.0GHz, the complex permittivity, permeability, magnetic
and electric loss tangents of FeCuNbSiB wires/wax composites are
strongly dependent on the annealing temperature and frequency.
For T = 573, 723 and 773K, two resonance peaks are found at
frequency f = 1.2 and 3.3GHz. However, for T = 673K,
only one resonance peak occurs at f = 3.3GHz. The resonance
peak at f = 1.2GHz is believed to be due to the
stress-induced anisotropy, while the resonance peak at f =
3.3GHz is attributed to the random anisotropy. 相似文献
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在计算摩擦力的教学中,对物体做受力分析时,常涉及到有多个弹力N,由于学生对f=uN公式中摩擦力f与弹力N关系的不够理解,因而容易忽略f与N之间的内在联系.下面通过实例来谈谈摩擦力计算中的此类问题. 相似文献
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Raj Bali R. S.Tikekar 《中国物理快报》2007,24(11):3290-3292
The C-field cosmological model based on the Hoyle-Narlikar theory with variable gravitational constant G is investigated. To obtain the deterministic value of C=dC/dt we present certain constant values for integration constants. The creation field is proportional to time. G and p (density) decrease with time and the universe represents an expanding universe. The creation field increases as time increases. We find C=√1/2πf t where f〉0,Thus C=1 when f=1/2π〉0. 相似文献
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物理与数学是两门古老的学科 ,它们之间有着密切的联系 ,下面用例子浅谈物理与数学的相互应用 .1 物理在数学上的应用在物理学里 ,我们知道 :若 AB为一根以O为支点的平衡杠杆 ,A、B、O三点受力分别记为 f A、 f B、 f O,则由杠杆原理知 :AOOB=f Bf A且 f O=f A f B从而得 :AO 相似文献
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介绍了平面波算法计算声子晶体带结构的分析过程,计算了二维双组分液相体系声子晶体的带结构.结果表明,四氯化碳/水银体系比水银/四氯化碳体系更容易产生带隙.随分散相填充分数f的增加,四氯化碳/水银体系声子晶体带隙宽度ΔΩ先增加,后减小,当f=0229时,有最大值ΔΩ=0549;水银/四氯化碳体系的带隙宽度一直增大,当f=0554时,有最大值ΔΩ=0515;f一定时,改变分散相单元的几何尺寸和点阵常数,带隙宽度ΔΩ保持不变.
关键词:
声子晶体
声子带隙
平面波算法
带结构 相似文献
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The investigation was made of the dependence of the intensity of Tl, Ga, Mo, Mg, Mn, Sn, Bi, Ni, Zn, Pt and Au spectral lines and the plasma parameters (temperature T, electron concentration ne, degree of 6 ionnization α) from concentration of lithium additive. 相似文献
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Let G be one of the local gauge groups C(X, U(n)),C
(X, U(n)), C(X, SU(n)) or C
(X, SU(n)) where X is a compact Riemannian manifold. We observe that G has a nontrivial group topology, coarser than its natural topology, w.r.t. which it is amenable, viz. the relative weak topology of C(X, M(n)). This topology seems more useful than other known amenable topologies for G. We construct a simple fermionic model containing an action of G, continuous w.r.t. this amenable topology. 相似文献
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Denis de Carvalho Braga 《Physics letters. A》2010,374(42):4316-4320
In this note we present an analytical study of the stability of the equilibria of the Rikitake system. We prove that the two non-hyperbolic equilibria of the Rikitake system are unstable for all positive values of the parameters. 相似文献
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