Design of a 3 GHz Accelerator Structure for the CLIC Test Facility (CTF 3) Drive Beam

For the CLIC two-beam scheme, a high-current, long-pulse drive beam is required for RF power generation. Taking advantage of the 3 GHz klystrons available at the LEP injector once LEP stops, a 180 MeV electron accelerator is being constructed for a nominal beam current of 3.5 A and 1.5 microsecond pulse length. The high current requires highly effective suppression of dipolar wakes. Two concepts are investigated for the accelerating structure design: the "Tapered Damped Structure" developed for the CLIC main beam, and the "Slotted Iris - Constant Aperture" structure. Both use 4 SiC loads per cell for effective higher-order mode damping. A full-size prototype of the TDS structure has been built and tested successfully at full power. A first prototype of the SICA structure is being built.Comment: Contribution to Linac 2000 Conference, TUA16 (Poster

Live-Cell Imaging of Single Receptor Composition Using Zero-Mode Waveguide Nanostructures

We exploit the optical and spatial features of subwavelength nanostructures to examine individual receptors on the plasma membrane of living cells. Receptors were sequestered in portions of the membrane projected into zero-mode waveguides. Using single-step photobleaching of green fluorescent protein incorporated into individual subunits, the resulting spatial isolation was used to measure subunit stoichiometry in α4β4 and α4β2 nicotinic acetylcholine and P2X2 ATP receptors. We also show that nicotine and cytisine have differential effects on α4β2 stoichiometry

Social capital as resources and capabilities in small firms' international performance – evidence from UK SMEs in ASEAN

This thesis contributes to the international business (IB) literature by examining different effects of three social capital dimensions on the internationalisation of SMEs in psychically distant markets from the resources and capabilities perspective. I propose a conceptual model that illustrates the behavioural process in which the entrepreneurial characteristics and resources embedded in social capital create a unique capabilities package to help a firm exploit emerging opportunities and enhance its international performance in foreign markets. The study employed a mixed research methodology, starting with longitudinal case studies of four British SMEs which to Vietnam, followed by an online survey of 157 British SMEs in the process of internationalising to ASEAN (the Association of Southeast Asian Nations). The study introduced two new concepts: (1) organisational network social capital which includes internal resources allocated to export activities and external resources gained from weak ties; and (2) entrepreneurial social capital which comprises proactive managerial attitudes and foreign market experience that SMEs' top management team have accumulated in foreign markets. The study found that organisational social capital and managerial proactiveness enhance overseas market exploitative capabilities, whilst trust and strategic export intention mediate the relationship between exploitative capabilities and international performance. Market experience was found to have a moderating effect on the relationship between exploitative capabilities and trust. The study contributes to the current social capital literature from theoretical, methodological and empirical perspectives: (1) it extends previous studies on internationalisation process of small firms by investigating the impact of resources and capabilities at both individual and organisational levels; (2) it disentangles different effects of each social capital dimension on dynamic capabilities and international performance in the post-entry stage; (3) it tests the evolution of commitment in different stages and highlights the trust-commitment mediation effect in the exploitative capabilities - performance link; (4) to the best of my knowledge it is the first study which applies longitudinal studies and an extended online survey in the context of the ASEAN trade bloc