No abstract available

[en] The nature of superconductivity in granular composite materials is discussed, starting from a microscopic Hamiltonian. The Ginzburg-Landau free energy arising from the Hamiltonian is presented. For weak enough intergranular coupling, the superconducting transition splits into two parts, a single grain ordering temperature T/sub co/, and a long-range phase ordering temperature T/sub c/. Numerical results are presented for the order parameter and specific heat in three dimensions. Calculations of the conductivity and susceptibility are also presented

[en] A new instrument is being established on the SRS wiggler beamline at Daresbury. The design consists of a toroid focussing mirror to produce a point focussed white beam of X radiation of an intensity sufficient for millisecond and sub-millisecond Laue exposures from protein crystals. The wavelength band available for focussed Laue experiments will be variable by means of a plane mirror with an adjustable graze angle and by adjustable thickness beryllium filters. Unfocussed white beam will also be available to provide the full spectral range of the wiggler source. New, larger film cassettes and changing mechanisms are being designed to use the available data more efficiently (by decreasing spatial overlap and increasing the number of recording 'singlet' reflections). A double crystal monochromator option will be available for rapidly tunable monochromatic data collection. Design principles based on theoretical work and ray-tracing are dealt with in the paper. (orig.)

[en] The distribution of capture zones formed during the nucleation and growth of point islands on a one-dimensional substrate during monomer deposition is considered for general critical island size i. A fragmentation theory approach yields the small and (for i = 0) large-size asymptotics for the capture-zone distribution (CZD) under the assumption of no neighbour–neighbour gap-size correlation. These CZD asymptotic forms are different to those of the generalized Wigner surmise which has recently been proposed for island nucleation and growth models, and we discuss the reasons for the discrepancies. (paper)

[en] This paper describes a unique combined UHV MBE growth x-ray topography facility designed to allow the first real-time synchrotron radiation x-ray topography study of strained-layer III--V growth processes. This system will enable unambiguous determination of dislocation nucleation and multiplication processes as a function of controlled variations in growth conditions, and also during post-growth thermal processing. The planned experiments have placed very stringent demands upon the engineering design of the system, and design details regarding the growth chamber; sample manipulator, x-ray optics, and real-time imaging systems are described. Results obtained during a feasibility study are also presented

[en] Countries are known to follow diverse pathways of life expectancy and carbon emissions, but little is known about factors driving these dynamics. In this letter we estimate the cross-sectional economic, demographic and geographic drivers of consumption-based carbon emissions. Using clustering techniques, countries are grouped according to their drivers, and analysed with respect to a criteria of one tonne of carbon emissions per capita and a life expectancy over 70 years (Goldemberg’s Corner). Five clusters of countries are identified with distinct drivers and highly differentiated outcomes of life expectancy and carbon emissions. Representatives from four clusters intersect within Goldemberg’s Corner, suggesting diverse combinations of drivers may still lead to sustainable outcomes, presenting many countries with an opportunity to follow a pathway towards low-carbon human development. By contrast, within Goldemberg’s Corner, there are no countries from the core, wealthy consuming nations. These results reaffirm the need to address economic inequalities within international agreements for climate mitigation, but acknowledge plausible and accessible examples of low-carbon human development for countries that share similar underlying drivers of carbon emissions. In addition, we note differences in drivers between models of territorial and consumption-based carbon emissions, and discuss interesting exceptions to the drivers-based cluster analysis. (paper)