Amplitude and Phase Fluctuations of Decimeter Radio Waves Raying the Atmosphere via Satellite-to-Satellite Paths

We present the results of experimental studies of the atmospheric phase and amplitude fluctuations of decimeter radio waves in radio occultation measurements using paths connecting the MICROLAB satellite and the satellites of the GPS navigation system. The dependences of the amplitude- and phase-fluctuation variance on the minimum altitude of the ray trajectory and the frequency spectra of the fluctuations are presented. The experimental data are compared with the theory of radio-wave propagation in random media. We determine the spectral index of irregularities of the atmospheric refractive index, the external scale of the irregularities, and the variance of the refractive-index fluctuations. It is shown that the radio occultation technique allows one to monitor small-scale irregularities of the atmosphere.     

Technique and Instrumentation for Precision Measurements of the Intensities of Extraterrestrial Radio Sources

We consider methods for decreasing the measurement error of the intensities of radio sources. The design of a two-temperature standard of noise radiation for calibrating antennas in the case of absolute measurements of the radiation flux densities of radio sources by the method of a black disk is described. We consider a method for taking into account the nonuniformity of the intensity distribution around the studied cosmic source, which facilitates choosing reference regions.     

Ambiguity of the Reconstruction of Plasma Frequency Profiles from a Given Height-Frequency Characteristic and Their Discernibility for Oblique Propagation of HF Radio Waves in an Isotropic Ionosphere

We specify the formulation of the problem of reconstructing the plasma frequency height distribution from a given height-frequency characteristic (HFC) for a spherically symmetric isotropic ionosphere. We propose a numerical algorithm for solving the problem of correctly processing the region of near-critical frequencies of ionospheric layers. On this basis, we study the discernibility of plasma frequency profiles (PFPs) satisfying a given HFC when the properties of an obliquely propagating HF signal are analyzed.     

Influence of Magnetic-Field and Plasma-Density Inhomogeneities on the Propagation and Amplification of Radio Waves in the Solar Corona

We analyze the maser generation of millisecond spikes of the solar radio emission at the cyclotron resonance of a fast extraordinary wave in an inhomogeneous medium. It is shown that the magnetic-field inhomogeneity with parameters typical of the solar corona drastically reduces the time of electromagnetic-wave amplification, which is explained by the fact that these waves leave the resonance region in the wave-vector space. As a result, an unstable electron distribution can be formed. The efficient generation of radiation becomes possible only in such local regions where the influence of the magnetic-field inhomogeneity is compensated by small-scale inhomogeneities of the plasma density with typical scales ranging from tens to hundreds of kilometers. Taking the effect of inhomogeneous medium into account allows us to explain spatial and temporal characteristics of the spikes.     

多模准对称叠加态光场广义电场分量的高次振幅压缩

构造了由多模真空场|{0j}＞q和四个一般多模泛函相干态|{f(m)j(x,y,x)}＞q(m=1,2,3,4)这五个态任意线性叠加而成的五态叠加多模泛函量子叠加态光场|φ(5)(fj)＞q.利用多模压缩态理论,研究了态|φ(5)(fj)＞q的广义电场分量在其不等强度准对称叠加条件广义非线性不等幂次Nj次方振幅压缩特性.结果发现:①态|φ(5)(fj)＞q是一种普遍意义上的五态叠加多模泛函非经典光场;对于态|φ(5)(fj)＞q的不等强度准对称叠加情形,无论压缩次数Nj取偶数还是取奇数,在一定的条件下,态|φ(5)(fj)＞q的广义电场分量就可呈现出任意次不等幂次且周期性变化的广义非线性Nj次方振幅压缩效应;②态|φ(5)(fj)＞q的多模泛函相干态中各模经典振幅和经典相位等的空间任意分布特征以及经典强度和经典振幅的任意非对称空间分布特征将对其不等幂次振幅压缩效应的压缩结果及压缩程度等产生直接的影响.     

Analysis of Variations of the Muon and Hadron Components of Cosmic Rays at Different Phases of the Solar Activity During the 11-Year Solar Cycle

Physics of Atomic Nuclei - Variations of secondary cosmic rays on the Earth’s surface depend on the solar activity. To study these variations, neutron monitors and muon detectors are used....     

Relationship between Echo Intensity of Vastus Lateralis and Knee Extension Strength in Patients with Type 2 Diabetes Mellitus

Objective: This study aimed to determine the association between echo intensity (EI) of vastus lateralis and knee extension strength (KES) in patients with type 2 diabetes mellitus (T2DM). Methods: This retrospective study included a total of 304 patients (189 males and 115 females) with T2DM who were hospitalized for treatment or care. EI and muscle thickness (MT) of the right vastus lateralis were assessed from transverse ultrasound images. Maximal isometric KES was evaluated using a dynamometer and normalized for body weight (%KES). Results: %KES was significantly positively correlated with MT and stages of change for exercise behavior, and significantly negatively correlated with age, T2DM duration, and EI. %KES was significantly higher in male than in female. %KES was significantly higher in non-diabetic peripheral neuropathy (DPN) than in DPN. Stepwise multiple regression analysis showed that sex, age, T2DM duration, EI, and stages of change for exercise behavior were significant determinants of %KES. Conclusion: The study results suggest that EI is associated with %KES in patients with T2DM.     

Response of the Earth＇s Magnetosphere and Ionosphere to Solar Wind Driver and Ionosphere Load： Results of Global MHD Simulations

Three-dimensional global magnetohydrodynamic simulations of the solar wind-magnetosphere-ionosphere system are carried out to explore the dependence of the magnetospheric reconnection voltage, the ionospheric transpolar potential, and the field aligned currents （FACs） on the solar wind driver and ionosphere load for the cases with pure southward interplanetary magnetic field （IMF）. It is shown that the reconnection voltage and the transpolar potential increase monotonically with decreasing Pedersen conductance （∑ p ）, increasing southward IMF strength （Bs） and solar wind speed （Vsw）. Moreover, both regions 1 and 2 FACs increase when Bs and vsw increase, whereas the two currents behave differently in response to ∑p. As ∑p increases, the region 1 FAC increases monotonically, but region 2 FAC shows a non-monotonic response to the increase of ∑p ： it first increases in the range of （0,5） Siemens and then decreases for ∑p 〉 5 Siemens.     

Indecomposable Representations of the Square—Root Lie Algebras of Vector Type and Their Boson Realizations

The explicit expressions for indecomposable representations of nine square-root Lie algebras of vector type, R_νλ (ν, λ=0, ±1), are obtained on the space of universal enveloping algebra of two-state Heisenberg-Weyl algebra, the invariant subspaces and the quotient spaces. From Fock representations corresponding to these indecomposable representations, the inhomogeneous boson realizations of R_νλ are given. The expectation values of R_νλ in the angular momentum coherent states are calculated as well as the corresponding classical limits.     

Liouville Type Equations with Singular Data¶and Their Applications to Periodic Multivortices¶for the Electroweak Theory

Motivated by the study of multivortices in the Electroweak Theory of Glashow–Salam–Weinberg [33], we obtain a concentration-compactness principle for the following class of mean field equations: on M, where (M,g) is a compact 2-manifold without boundary, 0 < a≤K(x)≤b, x∈M and λ > 0. We take with α _i > 0, δ _{p i} the Dirac measure with pole at point p _i ∈M, i= 1,…,m and ψ∈L ^∞(M) satisfying the necessary integrability condition for the solvability of (1)_λ. We provide an accurate analysis for solution sequences of (1)_λ, which admit a “blow up” point at a pole p _i of the Dirac measure, in the same spirit of the work of Brezis–Merle [11] and Li–Shafrir [35]. As a consequence, we are able to extend the work of Struwe–Tarantello [49] and Ding–Jost–Li–Wang [21] and derive necessary and sufficient conditions for the existence of periodic N-vortices in the Electroweak Theory. Our result is sharp for N= 1, 2, 3, 4 and was motivated by the work of Spruck–Yang [46], who established an analogous sharp result for N= 1, 2. Received: 24 September 2001 / Accepted: 7 December 2001     

Effect of Amplitude and Phase Distortions on the Formation of Light Fields with Rotating Intensity Distribution

The results of numerical simulation and experiments on the effect of amplitude and phase distortions on the formation of the light fields with the rotation of intensity distribution during propagation are presented. Practically significant cases of amplitude and phase distortions with regular and random inhomogeneity types are considered.     

Global existence of solutions for the relativistic Boltzmann equation with arbitrarily large initial data on a Bianchi Type I space-time

We prove, for the relativistic Boltzmann equation on a Bianchi Type I space-time, a global existence and uniqueness theorem, for arbitrarily large initial data.