Showing papers in "Protein Science in 1983"

Localized-Particles Approach for Classical and Quantum Crystals

Abstract: This paper is the first review devoted to the localized-particles approach for strongly anharmonic crystals. We present mathematical basises of such an approach for classical and quantum cases and we discuss its different applications. In the framework of this method various technical tricks and detailes could, of course, be changed, but the main idea should be conserved: that of the localization of atoms, forming a solid, near their lattice sites. The localized-particles approach describes not only collective excitations as the phonons but the state of particles themselves too; that is why it is much more convenient for describing crystals with defects, crystal-gas intersurfaces, disordered solids and some phase transitions.

Nonlinear Transformations and Integrable Evolution Equations

Abstract: The transformation properties of the partial differential equations integrable by the inverse scattering transform method are considered. It is shown that the nonlinear transformations characteristic to the integrable equations (symmetry groups, Backlund-transformations) and integrable equations themselves are contained in certain universal nonlinear transformations group which is defined by linear spectral problem.

On a Three-Body Problem in Relativistic Quantum Mechanics

Abstract: Proceeding from the method of packing operators developed by Sokolov and from the “light front variables” technique, the explicit formulae for packing operators and auxiliary mass operators for a system of three particles with arbitrary spins are derived. It is shown that for the packing operators there exists an infinite number of solutions yielding different physical consequences. The problem of the theory substantiation is discussed; the arguments in favour of a certain choice of packing operators are produced.

A Spinorization of a Constrained Vector System and a Spinor Reconstruction Theorem

Abstract: An elementary method of conctructing a spinor from vectors satisfying constraint conditions is proposed. We consider orthonormal triad and tetrad as an orientable physical object and introduce parameter representations of them, in terms of the Euler angles and the pseudo-Euler angles. Having determined the transformation property of the parameters, we set up the spinor determining equation. This equation is solved. The solution (spinor) contains four arbitrary complex constants, in 3 + 1 dimensional space. Using the proposed method, we prove the spinor reconstruction theorem, i.e. the original Dirac spinor can be reconstructed from seven of the sixteen hermitian bilinear forms, except the overall phase factor (the gauge freedom of the 1st kind). The energy density of the spinor field is written in terms of currents and their space derivatives.

Untersuchungen an dichtenz-Pinch-Plasmen

Abstract: Nach einem Uberblick uber die bisher veroffentlichte Literatur zu Messungen an z-Pinch Plasmen wird hauptsachlich uber spektroskopische Untersuchungen an dichten Plasmen berichtet. Als Plasma quelle dient einmal ein dynamischer z-Pinch, der Elektronendichten im Bereich 5 · 1017 cm−3 ≦ Ne ≦ 5 · 1019 cm−3 bei Temperaturen von 10 eV>kTe>3 eV bereitstellt. Aus Messungen der Kontinuumslichtintensitat, die im Wellenlangenintervall von 200 nm ≦ λ ≦ 12 μm durchgefuhrt wurden, sind die Elektronendichte und die Elektronentemperatur abgeleitet worden. Fernerhin gibt uberthermische Lichtemission bei langen Wellenlangen Hinweise auf die Mikroturbulenz, die durch den elektrischen Stromflusangefacht wird. Bei Untersuchungen der Hα-Linie wurden Linienverschiebungen und„Strukturen” auf die Spektrallinie naher analysiert. Es konnte aus dem selbstumgekehrten Teil der Linie Auskunft uber das Magnetfeld der Korona gewonnen werden, die das dichte Plasma-umgibt. Fur die Untersuchung der Wechselwirkung zwischen einem dichten Plasma und einem leistungsstarken CO2-Laser-Strahl liefert der dynamische z-Pinch ein vollionisiertes und gut reproduzierbares Ausgangsplasma. Es wird in diesem Zusammenhang der Problemkreis der induzierten Brillouin-Ruckstreuung analysiert. Neben dem konventionellem z-Pinch wird eine neuartige Entladungsart, der „gasummantelte Pinch” beschrieben. Nach theoretischen Vorstellungen wird dieser z-Pinch dadurch stabilisiert, das er von einem dichten Gasmantel umgeben wird. Die ersten Untersuchungen bestatigen die Stabilisierung der gefahrlichsten langwelligen Instabilitaten; kurzwellige Instabilitaten konnen jedoch nicht vollstandig unterdruckt werden.

Studies of Coupled Anharmonic Oscillator Problem Using Coherent States and Path Integral Approaches

Abstract: The present review is devoted to the study of the problem of coupled anharmonic oscillators. A perturbative solution is obtained for the system of an undamped and the damped coupled anharmonic oscillators in the coherent state representation. The solution does not contain the vicious secular terms and shows, explicitly, the anharmonic effects of a coupled system. In order to derive the perturbative solution of a damped coupled system a new frame of time, called quasi time τ, has been exploited. The large quantum number behaviour of coupled anharmonic oscillators has been derived using the path integral method.

Linear and Nonlinear Generalizations of Onsager's Reciprocity Relations. Treatment of an Example of Chemical Reaction Kinetics

Abstract: Linear and nonlinear generalizations of Onsager's reciprocity relations are derived from the fact that the time derivatives and time integrals of state quantities calculated by the help of the kinetic equations are state quantities again. Maxwell's reciprocity relations of thermostatics appear as special cases. The formalism is applied to a system of three linear dependent chemical elementary reactions. Onsager's relations and their generalizations are phenomenologically derived without the aid of the fluctuation theory. Es werden lineare und nichtlineare Verallgemeinerungen der Onsagerschen Reziprozitatsbeziehungen aus der Tatsache hergeleitet, das die mit Hilfe der kinetischen Gleichungen berechneten Zeitableitungen und Zeitintegrale von Zustandsgrosen wiederum Zustandsgrosen sind. Die Maxwellschen Reziprozitatsbeziehungen der Thermostatik erscheinen als Spezialfalle. Der Formalismus wird auf ein System von drei linear unabhangigen chemischen Elementarreaktionen angewendet. Die Onsagerbeziehungen und ihre Verallgemeinerungen werden phanomenologisch, ohne Zuhilfenahme der Fluktuationstheorie, hergeleitet.

The Non-Perturbative Approach to the Infrared Problem in QCD at Finite Temperature

Abstract: A non-perturbative approach is developed for investigation of the infrared problem in QCD at T ≠ 0 in the ghost-free axial gauge. The problem is solved by using a 3-dimensional theory within the exact Slavnov-Taylor identities and Schwinger-Dyson equations. The system of two non-linear integral equations for the structural functions of the gluon polarization tensor is obtained whose solution determines the infrared behavior of the temperature Green functions in the 4-dimensional QCD. The simplest solution of these equations which is the same as the first term of the perturbation expansion shows the presence of singularities in the gluon propagator at momenta p ∼ g2T, that cannot be eliminated by any choice of the gauge. The infrared instability of QCD at T ≠ 0 caused by these singularities is discussed.

Four Dimensional Theories with Composite Gauge Fields and Their Supersymmetric Generalizations

Abstract: A fourlinear CP(N – 1) model which is classically equivalent to the (massive) electrodynamics with composite four-potential is shown to be renormalizable in 4 dimensions in the framework of 1/N expansion. Also a supersymmetric fourlinear CG(N, n) model is constructed and shown to be equivalent to the super-Yang-Mills model with composite gauge fields. A short introduction to sigma models and supersymmetric gauge theories is given.

Experimental Consequences of the Asymptotically Free SU(5)‐Model

Abstract: The experimental consequences of the asymptotically free SU(5)-theory are presented which make it possible to judge about its reliability. The phenomenology of the τ-lepton is analysed with special attention paid to the so-called exotic processes which must solve whether “light” or “heavy” the ντ-neutrino should be. These exotic processes are completely forbidden within standard SU(5) schemes. The problem of the finite mass of the e, μ-neutrino which is a four-component Dirac spinor interacting via the Zel'dovitch-Mahmound-Konopinski scheme is discussed. The finiteness of such neutrino mass is a peculiarity of the SU(5) theory under discussion, although its value is not fixed here in a unique way. The version of the theory wherein mν ≦ 10−3 eV is of especial interest since in this case the proton instability and the finite e, μ-neutrino mass are found to be explained in a common way as manifestations of the existence of superheavy leptoquark bosons in the theory. The possibility is pointed out to explain within the SU(5) theory under consideration the existing experimental situations concerning the search for parity violating effects in atoms. It is shown that the present SU(5) theory encounters no difficulty in this respect and can recommend itself to any experimental set of data, whereas the standard schemes of SU(5) unification cannot. Cosmological consequences of the asymptotically free SU(5) theory are briefly discussed and the latter is found to rather reasonably explain a number of facts about the very early evolution of the Universe.

Tensor Meson Dominance and e+e--Physics

Abstract: We report on the phenomenological status of tensor meson dominance. Some new results, mainly concerning hadronic decays of the 2++-meson χ2(3.55) and the heavy lepton τ are also included. Considering experimental errors, we find agreement of tensor meson dominance with experiment.

Nuclear Magnetic Resonance Imaging and Related Topics

Abstract: The up-to-date techniques of magnetic resonance imaging and related phenomena are surveyed. The first chapter, tutorial in character, summarizes magnetic resonance phenomena observed in static homogeneous magnetic fields, in magnetic field gradients and under radiofrequency irradiation. The second chapter deals with a theory of nuclear magnetic resonance (NMR) imagers and with typical applications of these techniques in medicine. The third chapter is devoted to the instrumentation for NMR imaging systems: magnets, coils, NMR spectrometers, transmitter/receiver systems, digital controllers, computer altorithms and image displays. The audience for this revue will include students, physicians, biomedical and electronics specialists started to work in this new branch of NMR and computer programmers as well.