Range of separation of potential tool for bioseparation, microchip electrophoresis system, for DNA polymorphisms on the human Y-chromosome.

For the requirement of a high, fast and sufficient technology to suit the needs of 21st century biotechnology, the separation range of a microchip electrophoresis system was studied. Two DNA fragments on the human Y-chromosome, SY594 (82 bp) and 12f2 (88 bp), were successfully separated with a reproducibility of 1.9% and an accuracy of 2.8%. Then, a mixture of 10 DNA markers ranging from 61 bp to 189 bp was successfully separated with high resolution. All of these results demonstrate the superiority of microchip electrophoresis as a tool for 21st century bioseparation.     

A coupled-channels treatment of the positive-parity resonances in4He

The coupled-channels formalism, which has been previously applied successfully to interpret the negative-parity resonances in⁴He, has now been extended to the positiveparity 2?ω resonances in this system. The 1p-1h approach has been modified to include coupling to the 2p-2h configurations, which also belong to 2?ω excitations, by using the effective operator formalism. The effect of the Pauli term in thes-wave channel is examined and is found to be important in reproducing the 0⁺,T=0 resonance energy and width. Resonances with spins up toJ ^π=3⁺ have been studied, and the agreement with available data is satisfactory. In particular, from the good fit to the asymmetry coefficientβ(E), one establishes the presence of a 2⁺,T=0 resonance around 35-MeV excitation in the system.     

NMR study in a single crystal of the one-dimensional antiferromagnet CsCuCl3

The Cu²⁺ hyperfine field directions were determined by means of the ⁶³Cu magnetic resonance on a single crystal of CsCuCl₃ in a dc magnetic field. They make an angle 57° with the c axis. It was suggested a possible spiral spin configuration with the Cu²⁺ spins lying in the c plane. From the temperature dependence of the nuclear resonance frequency it was deduced an energy gap of about 4°K for this antiferromagnetic compound.     

稀土对铜抗氧化性能的影响

铜易被空气氧化,尤其在热加工过程中。铜的氧化动力学已有报道。加入稀土元素可提高铜在500～900℃时的抗氧化能力。本文研究了含轻稀土的铜在室温至熔化状态下的氧化过程,并对氧化膜的成分及氧化机理进行了探讨。     

General semi-classical method for collective motion and its connection with the Rowe-Basserman and marumori theories,and adiabatic limits

In recent work, we have shown that in the adiabatic limit (large amplitude, small momentum), time-dependent Hartree-Fock theory (TDHF) yields a well-defined theory of large-amplitude collective motion which provides an essentially unique construction for a collective hamiltonian. An alternative theory, put forward by Rowe and Basserman and by Marumori is, apparently, not restricted to small momenta. We describe a general framework for the study of collective motion in the semi-classical limit without limitation on the size of coordinates or momenta, which includes all previous methods as limiting cases. We find it convenient, as in the past, to consider two general systems: first, a system with n degrees of freedom and no special permutation symmetry, and, second, a system of fermions described in TDHF. For both systems the problem can be formulated as a search for a hamiltonian flow confined to a finite-dimensional hypersurface in a phase space, which itself may be finite- or infinite-dimensional. Though, in general, there are no exact solutions to this problem, we can formulate consistent approximation schemes corresponding to both the adiabatic and Rowe-Basserman, and Marumori limits. We also show how to extend the momentum expansion, which underlies the adiabatic approximation, to higher orders in the momentum. We thereby confirm the structure of the theory found in our previous work.     

Displacement potentials for membranes in stretching and stress-function potentials for plates in bending

Summary This paper proposes to use Helmholtz's representation of displacement component for the formulation of flat plates in extension. This is an alternative formulation equivalent to the classical formulation using Airy's stress function. On the other hand, by means of Southwell's analogies, it is possible to introduce some new quantities called stress-function potentials which lead to an another alternative formulation of flat plates in flexure. Some simple examples for stretching and bending case illustrate the merits of the above mentioned formulation.

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Übersicht Zur Bestimmung des ebenen Spannungszustandes elastischer Medien wird die von Hehnholtz angegebene Darstellung verwendet, die eine Alternative zum üblichen Vorgehen unter Verwendung der Airyschen Spannungsfunktion bietet. Unter Verwendung der Southwellschen Analogie lassen sich als neue Größen die Potentiale der Spannungsfunktionen einführen, so daß eine Theorie der Plattenbiegung ähnlich wie die von Lagrange und Kirchhoff gewonnen wird. Das wird an einigen einfachen Beispielen erläutert.

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The author is grateful to Professor Ch. Massonet for his interest and encouregement during the course of this work.     

Partie finie d'un système dynamique et deux nouvelles démonstrations du théorème de Hopf

Sans résuméEquipe de Recherche n1 «Processus Stochastiques et applications» dépendant de la section n1 «Mathématiques, Informatique» associée au C.N.R.S.     

Delay model of glucose-insulin systems: Global stability and oscillated solutions conditional on delays

Recently P. Palumbo, S. Panunzi and A. De Gaetano analyzed a delay model of the glucose-insulin system. They proved its persistence, the existence of a unique positive equilibrium point, as well as the local stability of this point. In this paper we consider further the uniform persistence of such equilibrium solutions and their global stability. Using the omega limit set of a persistent solution and constructing a full time solution, we also investigate the effect of delays in connection with the behavior of oscillating solutions to the system. The model is shown to admit global stability under certain conditions of the parameters. It is also shown that the model admits slowly oscillating behavior, which demonstrates that the model is physiologically consistent and actually applicable to diabetological research.