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Chapter
Classification of Early Type Stars on the Dominion Astrophysical Observatory Photometric System
A classification method has been developed for early—type stars observed on the Dominion Astrophysical Observatory photometric system. Two reddening—independent parameters, Q(35) and Q(38), are used. Q(35) is a m...
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Chapter and Conference Paper
Close Binary Stars
Commission 42 convened for two business meetings and two scientific sessions. In the following, the minutes of the business meetings and a summary of the scientific meetings are presented, with the abstracts o...
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Article
The effects of psychotropic drugs on exploratory and stereotyped behaviour of rats studied on a hole-board
Exploratory and stereotyped behaviour of Male Wistar rats was studied on a hole-board. The two forms of behaviour were differentiated according to the pattern of hole-dip** activity. Increasing doses of dl-amph...
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Chapter
Primary production in the Amazonian aquatic ecosystem
The incomparable beauty of the energy/biomass exchange has its finest expression in the lakes of the Central Amazon. Blackwater, whitewater and clearwater rivers and streams flood the myriad ria and várzea lakes ...
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Chapter
Microbiology of Amazonian waters
The relation between river and lake in the Central Amazon is one that reflects evolutionary adaptation to the environment. Down through the millenia, a grand design has evolved. This design, or structure, has ...
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Chapter and Conference Paper
Resonant Magnetotransport in Short (0.25 – 9 μm) n+nn+ GaAs Structures
Magnetophonon resonance in thin (0.25 – 9 μm) n+nn+ GaAs structures is used to study quasi-elastic inter-Landau level scattering which is induced in the high electric fields (up to 20 kV/cm) achievable in structu...
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Chapter and Conference Paper
Magnetic Field Studies of Resonant and Non-resonant Tunnelling in n-(AlGa)As/GaAs Double Barrier Structures
The electrical properties of a series of double barrier tunnelling devices with well widths between 5 and 60 nm are investigated. It is shown that the bistability effect in the current-voltage characteristics ...
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Chapter and Conference Paper
Resonant Tunnelling Devices in a Quantising Magnetic Field
High magnetic fields, applied either parallel or perpendicular to the barriers, are extremely useful for investigating the electrical properties of resonant tunnelling structures [1–11]. By considering the cur...
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Chapter
Pressure Dependence of Negative Differential Resistance in AlGaAs/GaAs Double Barrier Resonant Tunnelling Devices up to 20 Kbar
We have investigated the pressure dependence of Negative Differential Resistance (NDR) features observed in the DC current-voltage (I-V) characteristics of AlxGa1-xAs/GaAs Double Barrier Resonant Tunnelling Devic...
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Chapter and Conference Paper
Magnetotunnelling Spectroscopy to Measure the Electron and Hole ε(k) Dispersion Curves in the Quantum Well of Resonant Tunnelling Structures
We investigate the effect of a large magnetic field, B, applied parallel to the plane of the barriers on the resonant I(V) currents of n- and p-type double barrier structures. The shifts in the electron resona...
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Article
Vacancy Promoted Interdiffusion in Quantum Wells and Applications to Optoelectronic Devices
In this paper we shall look at a technique, known as impurity free vacancy diffusion (IFVD) for selectively altering the optoelectronic response of quantum well material after growth with a view to monolithic ...
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Chapter
Resonant Tunnelling via the Bound States of Shallow Donors
We have performed a systematic study of GaAs/(AlGa)As resonant tunnelling diodes in which the quantum well is intentionally δ-doped with Si donors. By comparing the I(V) of such devices with control samples we...
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Chapter
Excited State Populations of the Quantum Wells of Double Barrier Resonant Tunneling Structures
The observation of electroluminescence recombination from electrons in both ground (El) and excited states (E2) of the quantum wells of double barrier resonant tunneling structures is reported. Analysis of the...
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Article
Inaugural national scientific medical meeting
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Article
Growth and characterization of (111)B InGaAs/GaAs multi-quantum well PIN diode structures
High quality piezoelectric strained InGaAs/GaAs multi-quantum well structures on (111)B GaAs substrates have been grown by solid-source molecular beam epitaxy in a PIN configuration. 10K photoluminescence (PL)...
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Chapter
Preservation of cosmetics and toiletries
With the manufacture of cosmetics and toiletries on an industrial scale it became from the commercial point of view very important to maintain the integrity of the products released for sale. Manufacturers, th...
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Article
Book reviews
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Article
Vacuum rabi splitting in semiconductor microcavities with applied electric and magnetic fields
We describe the use of measurements of vacuum Rabi splitting to extract values for the exciton oscillator strengths in In0.13Ga0.87As-GaAs and GaAs-Al0.2Ga0.8As quantum wells. By varying both field and temperatur...
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Chapter
Identification of Tunneling Mechanisms through GaAs/AlAs/GaAs Single Barrier Structires
We have identified the Γ-X and X-Γ intervalley tunneling mechanisms in GaAs/AlAs/GaAs single barrier p-i-n structures by employing electroluminescence and transfort techniques. We show that the Γ-X-Γ tunneling...
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Chapter
Magnetic and Electric Field Effects in Semiconductor Quantum Microcavity Structures
The effects of magnetic and electric field on the vacuum Rabi exciton-photon coupling in semiconductor quantum microcavity structures are presented. A number of phenomena are described including marked increas...
