Multilayer ring structures

A study of the behavior of axisymmetric structures is important for understanding the problem of the existence and stability of planet rings, spherical star constellations, and galaxies. The multilayer ring structure algorithm is developed on the basis of an exact solution to the problem of n-body gravitational axisymmetric interaction. As a result of the numerical integration of differential motion equations of point bodies composing the above structures, the evolution of several of their models is investigated. Some of them are invariable in configuration, others change forms due to interlayer interactions, and the rest throw part of bodies out of the structure.     

超导π环零环混合阵列的自发磁化

研究了超导π环零环的混合规则阵列，计算了阵列的自由能.结果表明，两个π环通过中间零环间接耦合使得两π环反向自发磁化能量较低.规则阵列中，相邻π环倾向于反向自发磁化.这一现象起因于超导波函数的量子相干效应. 关键词： 超导结 π环 零环 自发磁化     

A supersymmetric black ring

A new supersymmetric black hole solution of five-dimensional supergravity is presented. It has an event horizon of topology S1 x S2. This is the first example of a supersymmetric, asymptotically flat black hole of nonspherical topology. The solution is uniquely specified by its electric charge and two independent angular momenta. These conserved charges can be arbitrarily close, but not exactly equal, to those of a supersymmetric black hole of spherical topology.     

SHER-HIAF ring lattice design

The Super Heavy Experimental Ring (SHER), which is one of the rings of the next accelerator complex High Intensity Heavy Ion Accelerator Facility (HIAF) at IMP, has to be optimized for e-cooling. Its lattice is designed for two modes: the first is the isochronous mode, which is a time-of-flight mass spectrometer for short-lived secondary nuclei, the second is the storage ring mode, which is used for collecting and cooling the secondary rare isotope beams from the transport line. In order to fulfil its purpose, the ion optics can be set to different ion optical modes.     

SHER-HIAF ring lattice design

The Super Heavy Experimental Ring （SHER）, which is one of the rings of the next accelerator complex High Intensity Heavy Ion Accelerator Facility （HIAF） at IMP, has to be optimized for e-cooling. Its lattice is designed for two modes： the first is the isochronous mode, which is a time-of-flight mass spectrometer for short-lived secondary nuclei, the second is the storage ring mode, which is used for collecting and cooling the secondary rare isotope beams from the transport line. In order to fulfil its purpose, the ion optics can be set to different ion optical modes.     

Self-locked He-Ne ring laser

Experimental conditions necessary for self-pulsing to occur in a He-Ne ring laser are reported. These results are compared with predictions that are based upon theoretical models that have been presented in the literature. Good qualitative agreement is found in that theory and experiment both show that self-pulsing will only occur over a range of excitation. Quantitative results differed enough to indicate that additional refinement is needed even though the models have identified many of the important parameters involved.Supported by the US Army Research Office.     

Focusators into a ring

Using numerical and analytical approaches, we have computed the optical elements (focusators) required for focusing laser light into a narrow ring, a wide ring and a set of rings. A numerical comparison of the various computational techniques is reported. Finally the operation of a fabricated rotor axicon to focus light into a ring is reported.     

Ultrashort-pulse fiber ring lasers

Received: 18 February 1997/Revised version: 22 April 1997     

Pentagonal two-loop ring interferometer

Results of work on the assembly and adjustment of an original pentagonal, two-loop interferometer are reported; the interferometer is a passive version of a compact laser gravitational wave detector. It is shown that the correlative automatic noise-compensation system developed for the project is capable of lowering the phase noise level in the resultant signal channel of the detector by two orders of magnitude. Zh. Tekh. Fiz. 68, 121–125 (May 1998)     

椭圆截面圆环和扭圆环的转动惯量

首先建立了椭圆截面的圆环和扭圆环的数学模型,然后根据定义计算绕3个坐标轴的轴转动惯量和惯量积,其间充分利用截面图形的对称性对计算过程简化,得到一些有益的结论和结果.     

Three particles on a ring

We study the ergodic properties of three classical particles of unequal mass moving on a ring and colliding like hard points.Although it is generally believed that this system is ergodic, we show that extensive numerical calculations do not support this belief.This may be connected with our discovery that for vanishing total momentum, any initial state with one particle at rest is periodic, independent of the mass values.The analogous periodicity for two unequal mass particles bouncing in a one-dimensional box can be understood on the basis of a remarkable property of a billiard in the form of a rectangular triangle.     

Continuous-wave tunnel ring fiber laser

The continuous-wave oscillation of a tunnel ring fiber laser is demonstrated. The high losses encountered in tunneling systems are compensated for by a high-gain amplifying medium from barrier widths for 0 to lambda/2. The experimental observations are in good agreement with a simple theoretical model. This near-field probe system allows one to detect small displacements in the picometer range.     

Solitons in a ring superlattice

We consider the propagation of electromagnetic solitons in a ring superlattice formed by the successive deposition of coaxial ring-shaped layers lying in parallel planes. In contrast to a rectilinear (infinite) superlattice, in which either one soliton (a single solution) or an infinite number of solitons (fluxon solution), any finite number of equidistant solitons is possible in a ring superlattice. We calculate the constant component of the electric field along the axis of the superlattice and the density of the current of electron drag by solitons (solitonelectric current).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 79–81, November, 1990.     

Vibration insensitive optical ring cavity

The mounting configuration of an optical ring cavity is optimized for vibration insensitivity by finite element analysis. A minimum response to vertical accelerations is found by simulations made for different supporting positions.     

A simple ring resonator system

A simple technique for the alignment of a three mirror ring cavity system is described. It is also shown that walk-off and astigmatism problems can be eliminated with relative ease, providing notable advantages over alternative travelling wave cavity configurations.     

Spectra of soft ring graphs

We discuss a ring-shaped soft quantum wire modelled by δ interaction supported by the ring with a generally nonconstant coupling strength. We derive the condition which determines the discrete spectrum of such systems, and analyse the dependence of the eigenvalues and eigenfunctions on the coupling and ring geometry. In particular, we illustrate that a random component in the coupling leads to a localization. The discrete spectrum is also investigated in the situation when the ring is placed into a homogeneous magnetic field or threaded by an Aharonov-Bohm flux and the system exhibits persistent currents.

(Some figures in this article are in colour only in the electronic version)     

Chromium doped forsterite ring laser

Operation of a Cr⁴⁺: Mg₂SiO₄ crystal in a ring cavity is studied with different dopant levels. Threshold energies of 13 mJ, 10.6 mJ and 11 mJ were measured for Mitsui low-doped, Russian and Mitsui highly doped crystals respectively. Slope efficiencies of 0.9%, 1.1% have been obtained for the Mitsui low-doped and Russian crystals. An efficiency of 3.6% was recorded for the highly doped chromium forsterite crystal from Mitsui. The peak output wavelength is 1275 nm. These results are compared with these crystals in the simple cavity.