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1.
Three-dimensional (3D) modeling of the solar corona has been carried out on the basis of the magnetic field distribution on H-alpha charts for the epochs of solar eclipses that occur near the epoch of the polar magnetic field reversal. Analysis of the 3D modeling shows that:
- Besides the global neutral sheet, two high-latitude coronal neutral sheets are also observed during the epoch of the polar magnetic field reversal.
- The observed structure of the coronal streamers is due to a projection of the folds of corrugated neutral sheets on the picture plane rather than due to the peculiar configuration of the magnetic field lines.
2.
It is shown that
- an appreciable change of magnetic moment of a neutron star cannot occur via ohmic dissipation
- pulsars provide evidence for large internal magnetic fields in main sequence stars. If pulsars are born from stars with masses exceeding 3 ?⊙ the internal field must be of the order of 103-104 Gauss while if they derived from less massive urstars 102 Gauss are sufficient to give rise to a magnetic moment ofM~1030 Gauss cm3.
3.
We study the consequences of the KMS-condition on the properties of quasi-particles, assuming their existence. We establish
- If the correlation functions decay sufficiently, we can create them by quasi-free field operators.
- The outgoing and incoming quasi-free fields coincide, there is no scattering.
- There are may age-operatorsT conjugate toH. For special forms of the dispersion law ε(k) of the quasi-particles there is aT commuting with the number of quasi-particles and its time-monotonicity describes how the quasi-particles travel to infinity.
4.
J. Halbritter 《Applied Physics A: Materials Science & Processing》1986,39(1):49-57
Broad-area electrodes show electron emission already at electric field strengthsF≈107 V/m. This enhanced field emission (EFE) occurs only for contaminated surfaces. EFE is accompanied by photon emission and gas desorption yielding finally discharges. EFE is caused by dust and contaminants initiating the following effects: an electron is stochastically emitted in a trigger zone the electron gains energyΔE?eΔxF * which excites electronic states which relax by the emission of electrons, photons, and atoms where the positive charges left behind enhanceF *=βF (β?1) initiating so an electron avalanche, i.e., a high conductivity channel. Because of charge migration and neutralization, this avalanche has a life time. This pulsating EFE is accompanied by light emission and gas desorption yielding finally a gas cloud and a discharge. The pulsating, self-sustained EFE has the same root as: the enhanced secondary emission found first by Malter the conductivity switching exhibited by thin (≈ 1 μm) layers of semiconductors or insulators the normal cathode fall and the firing-wave instability in neurodynamics. 相似文献
5.
J. C. M. Henning J. H. den Boef 《Applied Physics A: Materials Science & Processing》1978,16(4):353-357
A novel method for measuring magnetostriction constants is presented. A strain, periodic in time, applied to the sample, causes a modulation of the ferromagnetic resonance line position. The height of the signal obtained after phase-sensitive detection is proportional to the strain modulation depth. The appropriate magnetostriction constant λ is obtained by comparing the height of the SMFMR signal with that of the FMR line, as recorded by means of magnetic field modulation. Features of the new technique are:
- high sensitivity: λmin? 10?9 forM=100 Oe and linewidth ΔH d=1 Oe;
- λ's belonging to distinct precession modes are separately determined;
- applicable to thin layers for which strain gauge techniques cannot be used;
- wide temperature range: 1.2 K<T<300 K;
- uniform stress.
6.
J. Ginibre 《Communications in Mathematical Physics》1969,14(3):205-234
We prove that the following lattice systems:
- anisotropic Heisenberg model,
- Ising model with transverse magnetic field,
- quantum lattice gas with hard cores extending over nearest neighbours,
7.
J. L. van Hemmen A. C. D. van Enter J. Canisius 《Zeitschrift für Physik B Condensed Matter》1983,50(4):311-336
A simple, exactly soluble, model of a spin-glass with weakly correlated disorder is presented. It includes both randomness and frustration, but its solution can be obtained without replicas. As the temperatureT is lowered, the spin-glass phase is reached via an equilibrium phase transition atT=T f . The spin-glass magnetization exhibits a distinctS-shape character, which is indicative of a field-induced transition to a state of higher magnetization above a certain threshold field. For suitable probability distributions of the exchange interactions.
- A mixed phase is found where spin-glass and ferromagnetism coexist.
- The zero-field susceptibility has a flat plateau for 0≦T≦T f and a Curie-Weiss behaviour forT>T f .
- At low temperatures the magnetic specific heat is linearly dependent on the temperature.
8.
9.
E. Boos I. Ginzburg K. Melnikov T. Sack S. Shichanin 《Zeitschrift fur Physik C Particles and Fields》1992,56(3):487-491
Three possibilities to observe the Higgs-top interation at future γγ-colliders are discussed:
- associated Higgs production via the \(\gamma \gamma \to t\bar tH\) reaction,
- Higgs obliged radiative correction to the \(\gamma \gamma \to t\bar t\) channel,
- Higgs resonance production via γγ→H→ZZ.
10.
J. Kupsch 《Communications in Mathematical Physics》1977,57(3):219-233
We give a complete proof of the existence of scattering amplitudesA(s,t,u) with the following properties
- the amplitudes are total symmetric ins,t, andu.
- they satisfy elastic unitarity for 4≦s≦16, and
- they develop resonances forl≧2 on a bounded Regge trajectory which dominates the asymptotics for large energies.
11.
As a model of the actual structure of the planetary plasmasphere, we consider the electrodynamical problem of electric field and current generation by a planet with a dipole magnetic field corotating with the plasma envelope. The plasma envelope is characterized by the conductivity and angular velocity of the magnetospheric plasma as functions of the distance τ from the planet center and the angle ? measured from the rotation axis. The exact solutions of the Maxwell equations are obtained in the axially symmetric case within the framework of unipole electrodynamics when the rotational and magnetic axes coincide. These solutions describe the possible distributions of electric fields, currents, and charges in the rotating plasma envelope surrounding the magnetized planet. As an exmple, we constructed, using the theory proposed, the exact solution corresponding to the following structure of the plasmasphere:
- the plasmasphere region corotating with the planet and located between L-shells (L=τ/Rsin 2 ?, where R is the radius of the planet) from L=1 to L=L*;
- the polar region with differential, spherically symmetric rotation;
- the transient region of the plasmasphere rotating differentially with the angular velocity dependent on the L-number and located between L-shells from L=L* to L=L*+L0;
- the external (vacuum) region.
12.
We derive new inequalities for the plane rotator ferromagnetic model and use them to obtain the following results:
- If the model is isotropic, the derivability of the free energy as function of the magnetic fieldh implies the existence of a unique translation invariant Gibbs state and if furthermoreh=0 all Gibbs states are invariant by rotation of the spins.
- If the model is anisotropic the above assertion holds forh non-zero.
- If the model is anisotropic then there are at most two extremal translation invariant Gibbs states for almost all values of the anisotropy parameter.
13.
M. J. Rycroft 《Radiophysics and Quantum Electronics》1996,39(1):3-17
An overview of the subject of space plasma physics is attempted. This encompasses a discussion of various ground-based and satellite studies of the near-Earth space environment, with its marked temporal and spatial variations, theoretical investigations, and numerical simulations. The important distinction is drawn between passive studies of elements of the natural system, aimed at the difficult task of understanding the self-consistent evolution of some natural processes, and active investigations, which either probe or modify natural processes, in order to improve understanding of cause and effect (e.g. of energy transformations) within the system. Linear, nonlinear, and chaotic processes can occur. Attention is paid to:
- Energetic events on the Sun,
- Large-scale features of the interplanetary medium, both observed directly and via scintillations of distant radio stars,
- The magnetosphere in general, and the aurora in particular,
- Wave-particle interactions, especially cyclotron resonance phenomena, and
- The ionosphere, particularly when heated by powerful radio waves.
14.
C. v. Westenholz 《International Journal of Theoretical Physics》1971,4(4):305-320
Wheeler's conjecture that there might exist a ‘principle’ which rules out parity-non-conserving spaces is analysed. The following result has been obtained: A local relativistic quantum field theory is parity-conserving if the following conditions hold:
- The fields are derived from geometry, i.e. they are represented by quantised currents (in the sense of de Rham); and
- The theory may be defined on a connected and, under certain restrictions, on a disconnected orientable space-time continuumM 4.
15.
A. Zumsteg M. Ziegler Prof. Dr. W. Känzig M. Bösch 《Zeitschrift für Physik B Condensed Matter》1974,17(4):267-291
The phase transitions of Alkali-Hyperoxide crystals (NaO2, KO2, RbO2, and CsO2) grown in liquid ammonia have been investigated by means of the following measurements:
- magnetic susceptibility
- differential magnetic susceptibility as magnetic field
- magnetization curve in static and pulsed fields
- specific heat.
16.
E. Mourre 《Communications in Mathematical Physics》1981,78(3):391-408
We give a sufficient condition for a self-adjoint operator to have the following properties in a neighborhood of a pointE of its spectrum:
- its point spectrum is finite;
- its singular continuous spectrum is empty;
- its resolvent satisfies a class of a priori estimates.
17.
In this paper measurements of the frequency, linewidth and polarization of stimulated recombination radiation (SRR) fromp-type InSb are reported. The samples had low excess-carrier concentrations between 1014 and 1015 per cm3 and different lengths between 0.4 and 9 mm. They were held in magnetic fields up to 6T at temperatures of pumped liquid helium. The excitation was done optically by the radiation of a Q-switched CO-laser. We could observe a number of different stimulated processes:
- band-to-band recombination (tuning between 1875 and 1980 cm?1),
- band-to-acceptor recombination (tuning between 1840 and 1930 cm?1),
- stimulated spin-flip Raman scattering (SFR) of the SRR by excited electrons,
- SFR of the laser by excited electrons and its interaction with the SRR.
18.
Michael Henle 《Communications in Mathematical Physics》1970,19(4):273-275
Theorem. Let a topological groupG be represented (a→φ a ) by *-automorphisms of a von Neumann algebraR acting on a separable Hilbert spaceH. Suppose that
- G is locally compact and separable,
- R′ is properly infinite,
- for anyT∈R,x,y∈H the function
19.
It is demonstrated that a closed symmetric derivation δ of aC?-algebra \(\mathfrak{A}\) generates a strongly continuous one-parameter group of automorphisms of aC?-algebra \(\mathfrak{A}\) if and only if, it satisfies one of the following three conditions
- (αδ+1)(D(δ))= \(\mathfrak{A}\) , α∈?\{0}.
- δ possesses a dense set of analytic elements.
- δ possesses a dense set of geometric elements.
- ∥(αδ+1)(A)∥≧∥A∥, α∈IR,A∈D(δ).
- If α∈IR andA∈D(δ) then (αδ+1)(A)≧0 impliesA≧0.
20.
A. Jánosi 《Zeitschrift für Physik B Condensed Matter》1990,80(3):393-400
We study the effects of some of the most important and typical structural changes in two-phase systems on selected structural parameters obtained from small-angle x-ray scattering (SAXS) measurements. To limit the present study, it was assumed that the Phase, 1, embedded in the matrix
- is monodispersed and homogeneous,
- possesses one of the three most extreme shapes (spherical, fibrillar or lamellar) and
- changes its behaviour
- through type change (spinodal or nucleotic or coarsening), without changing the shape,
- through a change of the shape only, or
- through a) (type change) and b) (shape change) simultaneously.
- chord lengthl 1 (and/or radius of gyrationR),
- volume partw 1 of the Phase 1, and
- relative inner surfaceS v of the system.
- spinodal change, all three SAXRS parameters are increasing or decreasing simultaneously and proportional to a power of the intensity of the change,
- nucleotic change,l 1 (and/orR) is unchanged, the other two (w 1 andS v ) are increasing or decreasing simultaneously and directly proportional to the intensity,
- coarsening change,w 1 is unchanged and anincreasing ofl 1 is always accompanied by adecreasing ofS v and vice versa.