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It is shown that for fully ionized hydrogen and helium plasmas the resolving equation will have the form of the sinhGordon equation and BulloughDoddZhiberShabat equation (with elliptic operator), respectively.


Intensity of recombination of charged particles on some borides of refractory metals in a weakly ionized hydrogen plasma


The selfsimilar motion of a completely ionized hydrogen plasma is considered in the twotemperature hydrodynamic approximation, i.e., we consider the plane piston problem and the problem on energy release at a fixed wall.


Selfsimilar solution of the NavierStokes equations for a completely ionized hydrogen plasma (the plane piston problem)


Some applications of relaxation theory of a highly ionized hydrogen plasma

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 Chisnell no's method is applied to studying the propagation of a perpendicular hydromagnetic shock wave in the inhomogeneous magnetic field. A new shock parameter, the characteristic velocity of shock wave representing' the geometric mean of the shock velocities in both sides of the front, has been introduced. The propagation equation thus obtained is greatly simplified. The equation is integrated by numerical method in the case of "strong magnetic medium", where the Alfvén velocity is much greater than the... Chisnell no's method is applied to studying the propagation of a perpendicular hydromagnetic shock wave in the inhomogeneous magnetic field. A new shock parameter, the characteristic velocity of shock wave representing' the geometric mean of the shock velocities in both sides of the front, has been introduced. The propagation equation thus obtained is greatly simplified. The equation is integrated by numerical method in the case of "strong magnetic medium", where the Alfvén velocity is much greater than the sound velocity. Three types of particle density distribution are considered: (1) the Alfvén velocity is constant, (2) the density is uniform and (3) the ratio of the density to the field intensity remains constant. It is shown that when a shock wave propagates from a weak field into a strong one, its strength measured by the jump ratio of field intensity always decreases. For medium with a constant Alfvén velocity the shock wave decays most slowly; for a medium of uniform density the shock wave attenuates most quickly; while for the constant densityfield ratio medium the attenuation rate appears to be intermediate. In the weak shock limit, the amplitude of wave is inversely proportional to the square root of the Alfvén velocity. These results are discussed in relation to the magnetic shock propagating in the earth's magnetosphere on the assumption that the whole space is filled with wholly ionized hydrogen plasma whose density is proportional to the field intensity, as confirmed by whistler observation from 2 to 5 earth's radii distance. In this case, it is shown that a shock wave of initial velocity 10~8cm/sec at 10 earth's radii distance will excite a 60γ field change in the earth's surface, comparable to the order of magnetitude of the sudden commencement of a strong storm in the lower latitudes.  本文应用Chisnell no方法,求解了在理想介貭中,垂直磁流体冲激波在非均勻磁場中的传播問題。这种方法,把非均勻介貭分解成无限小的弱間断面,根据气体动力学中波与間断面相互作用的原理,算出激波通过弱間断面时的强度变化,然后用积分求得激波通过整个非均勻区时的强度变化。作者引入了激波的特征速度(它是激波在波前后介貭中传播速度的几何平均值)作为輔助参量,得到形式上比較簡单的激波传播方程。然后考虑了磁压力远大于气体压力的强磁介貭中的激波传播問題,并进行了数值积分。采用的介貭密度模型有三种:(1)阿尔芬波速为常数;(2)密度不变;(3)密度与磁場强度成正比。計算結果表明:当激波由弱磁場向强磁場传播时,激波的强度逐漸变弱。其中,在阿尔芬波速为常数的介貭中,激波强度的衰减最为緩慢;在密度不变的介貭中,激波强度的衰減最为迅速;而在密度与磁場成正比的介貭中,激波强度的衰減則介乎上述两种密度分布之間。作者联系磁流体冲激波在地球外层空間的传播問題进行了討論,密度的模型采取大气啃昔的观測結果(卽上述第三种密度分布),并进行了适当的外推,估計了在十个地球半径处的磁流体冲激波传到地面时的强度,求出了激波在地面引起的磁場变化与激波初始... 本文应用Chisnell no方法,求解了在理想介貭中,垂直磁流体冲激波在非均勻磁場中的传播問題。这种方法,把非均勻介貭分解成无限小的弱間断面,根据气体动力学中波与間断面相互作用的原理,算出激波通过弱間断面时的强度变化,然后用积分求得激波通过整个非均勻区时的强度变化。作者引入了激波的特征速度(它是激波在波前后介貭中传播速度的几何平均值)作为輔助参量,得到形式上比較簡单的激波传播方程。然后考虑了磁压力远大于气体压力的强磁介貭中的激波传播問題,并进行了数值积分。采用的介貭密度模型有三种:(1)阿尔芬波速为常数;(2)密度不变;(3)密度与磁場强度成正比。計算結果表明:当激波由弱磁場向强磁場传播时,激波的强度逐漸变弱。其中,在阿尔芬波速为常数的介貭中,激波强度的衰减最为緩慢;在密度不变的介貭中,激波强度的衰減最为迅速;而在密度与磁場成正比的介貭中,激波强度的衰減則介乎上述两种密度分布之間。作者联系磁流体冲激波在地球外层空間的传播問題进行了討論,密度的模型采取大气啃昔的观測結果(卽上述第三种密度分布),并进行了适当的外推,估計了在十个地球半径处的磁流体冲激波传到地面时的强度,求出了激波在地面引起的磁場变化与激波初始速度之間的关系。根据上述簡化模型,計算結果表明,在十个地球半径处初始速度为10~8厘米/秒的激波,传到地面引起的磁場变化大約为60伽(亻馬),这个数值的量級恰好与中低緯度强磁暴的急始变幅相符。  An important astrophysical consequent of the experiments regarding a nonzero rest mass of neutrinos is the possible existence of selfgravitating systems of neutrinos. The masses of stable equilibrium configurations of such systems are of the order of the mass of clusters of galaxies. On the other hand, in the standard model of big bang cosmology the mass density in the universe is dominated by neutrinos if it has a nonzero mass, say, mv  1446 ev. Hence it might be expected that the clustering of matter in... An important astrophysical consequent of the experiments regarding a nonzero rest mass of neutrinos is the possible existence of selfgravitating systems of neutrinos. The masses of stable equilibrium configurations of such systems are of the order of the mass of clusters of galaxies. On the other hand, in the standard model of big bang cosmology the mass density in the universe is dominated by neutrinos if it has a nonzero mass, say, mv  1446 ev. Hence it might be expected that the clustering of matter in the early universe should be affected substantially by such neutrinos.The clustering of pure neutrinos content in expanding universe has been investigated in several works, but in which the clustering of cosmological matter has not been involved yet, Since the results of direct measures on galaxies or on clusters of galaxies, for example, the mass, the size and the velocity dispersion are always the properties of matter components themselves, it is necessary to analyse the interaction between the clustering processes of the neutrinos and the matter,1, In the case of mv=0 the clustering theory of the Jeans instability stage in the early universe can be summarized in the Figs 1 and 2.Fig 1 show the Jeans wave length λm of ionized hydrogen plus blackbody radiation as a function of cosmological radiation temperature Tr. The corresponding time of the drop in the Jeans, length is the hydrogen recombination at Tr  4000 K. Before the recombination both ionized hydrogen and radiation are in thermal equilibrium by collisions with each, other, after the recombination the matter decoupled from radiation. Dashed line Mm in Fig 2 shows the Jeans mass as a function of radiation temperature. A drop in the time of recombination occures as well. The dashed line Mhor in Fig. 2 gives the mass contained within the horizon of the cosmological model.The mass range of the Jeans instability is given by Mm < M < Mhor. Then it can be obtained from the Fig. 2 that no preferential clustering size exists in this model, i.e. all systems with mass from about 106 to 1017 M⊙ are unstable against the Jeans mechanism in the early universe and all unstable developments start from the time of recombination. That is often considered as a shortage of the theory of early clustering in the big bang model. In this work we have shown that if neutrinos have a nonzero rest mass the conclusions mentioned above should become to advantage the big bang theory.2, As the age of the universe was longer than td or the temperature dropped below Td1.3×1011 K, the neutrinos and antineutrinos decoupled from the other particles so that we might adopt the twocomponents perfectfluid to represent the contents of the universe, one of the components is the neutrinos and the other is the matter and the radiation.For the component of matter and radiation, the thermodynamieal properties are still described by the results given in section 1. The component of neutrinos is a collisionless selfgravitating gas, for which the distribution function N(t, xi pi) satisfies the Vlasov equation. In the EobertsonWalker metric, using the distribution in the time td as the initial condition, the solution of the Vlasov equation can be found as follows:where B(t) is the cosmic scale factor in the RW metric and Rd =R(td).All thermodynamieal properties of the neutrinos systems can be obtained from the distribution (1). For instance, in the nonrelativistic case the effective temperature Teff of neutrinos arewhere mv is in the unit of ev. In the same way we can derived the Jeans wave length of the neutrino system (see Fig. 1).3, The twocomponents in the early universe interact with each other through gravitational force. When we want to examine the Jeans instability, the two components system should be treated as a whole. Strictly speaking, we must deal with this problem in the relastivistic and expansive cosmological model. We can, however, safely employ classical and nonexpansive model if our interests cover only the Jeans length and mass, but not the growing rate of small fluctuations. N  本文讨论有静质量中微子对宇宙早期的Jeans不稳定性阶段的成团过程的影响。把早期宇宙作为两成分流体处理,一种成分是退耦后的中微子,另一种成分是物质及辐射,二者之间仅通过引力相耦合。主要的结论是:(1)有静质量中微子将引起复合时期之前的物质成团过程;(2)这种先复合期的物质成团的质量主要处于星系团的范围;(3)存在优先的成团尺度,它的Jeans不稳定的起始时间最早;(4)如果中微子静质量太小,则对早期的物质成团过程无影响。  In this paper, based on the new model of potential function, the relativistic revision of excitation energy levels of the highly ionized hydrogen like atoms is presented. The soft X ray spectra of hydrogen like neon atom are calculated. The calculated results are in good agreement with the experiments.  在高电离态类 H离子新势函数模型基础上 ,对离子激发态能级进行了相对论修正 .对类H氖的软 X射线谱进行了计算 ,结果与实验值吻合较好 .   << 更多相关文摘 
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