A liénard oscillator resonant tunnelling diode-laser diode hybrid integrated circuit: model and experiment

We report on a hybrid optoelectronic integrated circuit based on a resonant tunnelling diode driving an optical communications laser diode. This circuit can act as a voltage controlled oscillator with optical and electrical outputs. We show that the oscillator operation can be described by Liénard's equation, a second order nonlinear differential equation, which is a generalization of the Van der Pol equation. This treatment gives considerable insight into the potential of a monolithic version of the circuit for optical communication functions including clock recovery and chaotic source applications

The Effects of the Division of the City of Lloydminster by the Alberta-Saskatchewan Inter-Provincial Boundary

L'article expose les conséquences, sur le développement de Lloydminster, de la localisation de la ligne frontière Alberta - Saskatchewan qui coupe cette cité en deux. Les problèmes de la duplication des services et des équipements publics encourageaient, dans les premières années d'existence de la communauté, les essais de fusion des deux parties de Lloydminster. Cette fusion a été accomplie en 1930, et la cité fonctionne sous une législation spéciale, le « Lloydminster Charter ». Les inefficacités inhérentes à cette division subsistent encore, en particulier pour le gouvernement municipal, de même que les désavantages pour les activités commerciales, parce que la législation provinciale de l'Alberta ou de la Saskatchewan s'applique aux individus, selon le côté de la ligne frontière où ils résident, travaillent, font leurs achats, ou possèdent des industries. La taxe de vente levée par le gouvernement de la Saskatchewan reste un problème pour les marchands et les habitants. La majeure partie du développement commercial et industriel se situe à l'ouest de la cité, c'est-à-dire en Alberta. Les sociétés industrielles et les marchands, les gens de métier et les habitants veulent que la cité soit située entièrement en Alberta ou entièrement en Saskatchewan pour supprimer les inefficacités et les irritations qui résultent de la division de la cité par la ligne frontière.The paper traces the effects of the superimposed inter-provincial boundary line on the development of Lloydminster. Duplication of public services, and other difficulties encouraged early efforts to amalgamate the community under one jurisdiction. This was accomplished in 1930 and the city is operated under special legislation which is called the « Lloydminster Charter ». Inherent inefficiencies still remain for civic government as well as disadvantages for private enterprises as the provincial legislation of Alberta or Saskatchewan prevails depending upon which side of the boundary a person resides, works, shops, or an economic enterprise is located. The sales tax levied on most purchases by the Saskatchewan Government remains a problem for retailers and citizens. Most of the commercial and industrial development is occurring on the Alberta side of the City. There is evidence that industrial and commercial companies, professional people and residents, would prefer the City to be either in Alberta or Saskatchewan in order to eradicate the inefficiencies and irritations caused by the division of the city by the boundary

Learning to nurse: combining simulation with key theory.

Following a recent Nursing and Midwifery Council revalidation of a university undergraduate nursing programme, simulation skills sessions and anatomy and physiology theory were integrated into one unit (module). This was done in order to integrate the basis for patient assessment and care provision with the anatomical and physiological theory and thereby enhance student learning and nursing practice. Students evaluated the new unit well and valued the close link between theory and practice simulation. Improvements were seen in the simulation skills sessions as students were better able to apply their underlying theory to their actions. Learning was enhanced as both simulation and theory were seen as more meaningful to practice and patient care

Modeling of light-sensitive resonant-tunneling-diode devices

We present a method to include the effects of light excitation on two different models of resonant-tunneling-diode-based devices. Our approach takes into account both photoconductive and charge accumulation effects responsible for shifting the static I –V curve when the structure is under light excitation. Computational simulations led to good agreement between the model and experimental result

Giant suppression of shot noise as signature of coherent transport in double barrier resonant diodes

Shot noise suppression in double barrier resonant tunnelling diodes with a Fano factor well below the value of 0.5 is theoretically predicted. This giant suppression is found to be a signature of the coherent transport regime and can occur near zero temperature as a consequence of the Pauli principle or above about 77 K as a consequence of long range Coulomb interaction. These predictions are validated by experimental data

Coherent approach to transport and noise in double-barrier resonant diodes

We implement a quantum approach which includes long range Coulomb interaction and investigate current voltage characteristics and shot noise in double-barrier resonant diodes. The theory applies to the region of low applied voltages up to the region of the current peak and considers the wide temperature range from zero to room temperature. The shape of the current voltage characteristic is well reproduced and we confirm that even in the presence of Coulomb interaction the shot noise can be suppressed with a Fano factor well below the value of 0.5. This feature can be an indication of coherent tunneling since the standard sequential tunneling predicts in general a Fano factor equal to or greater than the value 0.5. This giant suppression is a consequence of Pauli principle as well as long range Coulomb interaction. The theory generalizes previous findings and is compared with experiments