Living in the same household - ‘Incest’ in the family of sport

This article focuses on the coach/athlete relationship in the self admitted sporting ‘family’ and, using both the provisions of the Sexual Offences Act 2003 and the civil law remedies of non-molestation orders argues that where matters of abuse are concerned, the private world of the surrogate family of sport could be just as liable under family law principles as any other modern day informal family

Hyperfine anomaly in Be isotopes in the cluster model and the neutron spatial distribution

The study of the hyperfine anomaly of neutron rich nuclei, in particular, neutron halo nuclei, can give a very specific and unique way to measure their neutron distribution and confirm a halo structure. The hyperfine structure anomaly in Be+ ions is calculated with a realistic electronic wave function, obtained as a solution of the Dirac equation. In the calculations, the Coulomb potential modified by the charge distribution of the clustered nucleus and three electrons in the 1s^2 2s configuration is used. The nuclear wave function is obtained in the core+nucleon model of 9,11Be. The aim of this study is to test whether the hyperfine structure anomaly reflects a halo structure in 11Be.Comment: 8 pages, 1 figur

Dynamical switching characteristics of a bistable injection laser

The switching characteristics of a bistable injection laser with very large hysteresis is examined. Switch-on delays are shown to exhibit a "critical" part and a "noncritical" part, both of which can be reduced by increasing the overdrive current. It is possible to obtain fairly fast switching time (<20 ns) with a strong overdrive. Nominal delays of 100–200 ns result under moderate overdrives. These long time scales are due to long carrier lifetimes in the carrier-depleted absorption section, a property intrinsic to these bistable injection lasers

Longitudinal mode spectrum of GaAs injection lasers under high-frequency microwave modulation

Experimental observations of the lasing spectrum of a single mode semiconductor laser under continuous microwave modulation reveal that the lasing spectrum is apparently locked to a single longitudinal mode for optical modulation depths up to ~80%, beyond which the lasing spectrum becomes multimoded, whose envelope width increases very rapidly with further increase in modulation depth. These results are satisfactorily explained by a theoretical treatment which enables one to predict the dynamic lasing spectrum of a laser from its cw lasing spectra at various output powers

Bistability and pulsations in cw semiconductor lasers with a controlled amount of saturable absorption

Experimental results of a buried heterostructure cw laser with a controllable amount of saturable absorption introduced by a segmented contact are presented. With no absorption the laser is stable and has a linear output characteristic. Increasing of the saturable absorption by changing the pump current through the control segment causes the light output of the device to pulsate and to show bistable and hysteretical behavior. The introduction of a controllable amount of saturable absorption suggest the usefulness of this device in generating extremely short pulses, for example, by passive mode locking and as a bistable optical device

Bistability and negative resistance in semiconductor lasers

Experimental results of a buried heterostructure laser with a segmented contact to achieve inhomogeneous gain are presented. Measurements reveal a negative differential resistance over the absorbing section. Depending on the source impedance of the dc current source driving the absorbing section, this negative resistance can lead to (i) bistability with a very large hysteresis in the light-current characteristic without self-pulsation or (ii) a small hysteresis with self-pulsations at microwave frequencies. An analysis, which includes the electrical part of the device, leads to an explanation of self-pulsations in inhomogeneously pumped lasers without having to rely on a sublinear gain dependence on injected carrier concentration

Evaluation of the thermal and hydraulic performances of a very thin sintered copper flat heat pipe for 3D microsystem packages

The reported research work presents numerical studies validated by experimental results of a flat micro heat pipe with sintered copper wick structure. The objectives of this project are to produce and demonstrate the efficiency of the passive cooling technology (heat pipe) integrated in a very thin electronic substrate that is a part of a multifunctional 3-D electronic package. The enhanced technology is dedicated to the thermal management of high dissipative microsystems having heat densities of more than 10W/cm2. Future applications are envisaged in the avionics sector. In this research 2D numerical hydraulic model has been developed to investigate the performance of a very thin flat micro heat pipe with sintered copper wick structure, using water as a refrigerant. Finite difference method has been used to develop the model. The model has been used to determine the mass transfer and fluid flow in order to evaluate the limits of heat transport capacity as functions of the dimensions of the wick and the vapour space and for various copper spheres radii. The results are presented in terms of liquid and vapour pressures within the heat pipe. The simulated results are validated by experiments and proved that the method can be further used to predict thermal performance of the heat pipe and to optimise its design.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/EDA-Publishing

Multilayer gas cells for sub-Doppler spectroscopy

We have carried out theoretical research on ultra-high resolution spectroscopy of atoms (or molecules) in the suggested cell with a series of plane-parallel thin gas layers between spatially separated gas regions of this cell for optical pumping and probing. It is shown the effective velocity selection of optically pumped atoms because of their specific transit time and collisional relaxation in such a cell, which lead to narrow sub-Doppler resonances in absorption of the probe monochromatic light beam. Resolution of this spectroscopic method is analyzed in cases of stationary and definite nonstationary optical pumping of atoms by the broadband radiation versus geometrical parameters of given cells and pumping intensity. The suggested multilayer gas cell is the compact analog of many parallel atomic (molecular) beams and may be used also as the basis of new compact optical frequency standards of high accuracy.Comment: 12 pages, 4 figure