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The vibrations of the glasses SiO<SUB>2</SUB>, GeO<SUB>2</SUB>, GeS<SUB>2</SUB>, GeSe<SUB>2</SUB> and ZnCl<SUB>2</SUB> were investigated by Raman scattering in particular in the boson-peak region. Furthermore, to test for a correlation between boson peak and first sharp diffraction peak, five samples of amorphous As<SUB>2</SUB>S<SUB>3</SUB> quenched from different temperatures were investigated by neutron diffraction. The vibrational dynamics of amorphous GeO<SUB>2</SUB> was furthermore investigated very much in detail by neutron scattering on the instrument MARI, and with special emphasis on the low-frequency dynamics, on the instruments IN6 and DN6. On the latter two instruments, the vibrational dynamics of GeS<SUB>s</SUB> and GeS<SUB>2</SUB> were also investigated. A method for determining the partial mean-square displacement of a binary glass from the momentum-transfer dependence of the modes is presented, and it is suggested that employing the incoherent approximation in unsuitable regions can help discern peak positions. A further special point to note is the similarity of the momentum-transfer dependence of the modes and the static structure factor up to frequencies of 24meV. Concentrating on the temperature dependence of the low-frequency dynamics, glassy As<SUB>2</SUB>S<SUB>3</SUB> was investigated by neutron scattering on the instruments IN6 and MIBEMOL from far below the glass-transition to close to the boiling point. A point of special interest is the persistence of the first sharp diffraction peak to the highest temperature investigated. The study of relaxational dynamics was done on the glass formers As<SUB>2</SUB>S<SUB>3</SUB>I<SUB>1.65</SUB>, As<SUB>2</SUB>S<SUB>3</SUB>, and As<SUB>2</SUB>S<SUB>3</SUB>Ge<SUB>0.85</SUB> that were ascertained to be an intermediate, a strong, and a very strong (like SiO<SUB>2</SUB>) glass former, respectively, interpreting the results of penetration and plane-plate viscosity measurements from 10<SUP>12</SUP>Pa s down to 10<SUP>4</SUP>Pa s.

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Microwave plasma-enhanced chemical vapour deposition (PECVD) as a scalable and low temperature synthesis technique for carbon nanostructures has been investigated in this thesis. A PECVD reactor based on ASTeX-type microwave reactors was implemented to facilitate both contact and remote plasma operations. By creating a remote plasma environment and using sandwich-like catalytic structures (Al₂O₃/Fe/Al₂O₃), densely packed and vertically aligned single-walled carbon nanotubes (SWNTs) can be synthesized consistently for temperatures between 600-650°C. Carbon species ultimately responsible for SWNT synthesis are speculated to be the more stable and long-chained species from plasma activation. Wet chemistry techniques such as cobalt colloids and iron solution are alternatives to conventional physical vapour deposition methods for catalyst preparation. Silicon micrograss and carbon fibre matrices serve as limiting cases for extreme topology for three-dimensional catalyst coating using the wet chemistry techniques. Hierarchical control of the physical and chemical texture on wetting behaviour is demonstrated by selective carbon nanotubes growth based on microscale and nanoscale surface textures. Direct synthesis of SWNTs on carbon fibres is achieved using iron solution catalyst in the remote plasma environment. Carbon nanowalls are synthesized as freestanding three-dimensional aggregates. The differentiating morphology from the surface-bound material suggests a different growth mechanism, and similarities to the formation of carbon nanohorns. The results establish a scalable production method and possible applications based on the properties such as the stable field emission and high surface area.

A systematic method for selecting actuators (devices which produce a controlled force or displacement) for a given application is developed. Performance characteristics for several classes of actuator are presented in a graphical form which allows the characteristics of the actuator to be matched to the requirements of tasks. Some conclusions are drawn regarding the suitability of ferroelectric actuators for various tasks, and the opportunity offered by the non-linear, high force and high displacement regime of behaviour in ferroelectrics. A micromechanical constitutive model for the non-linear behaviour of ferroelectric crystals is developed. This model is based on the observation that ferroelectric transformations may be treated as if they were crystal slip systems, which allows conventional crystal plasticity models to be extended to the ferroelectric case. Expressions for the instantaneous tangent properties of a ferroelectric crystal are derived. The behaviour of the constitutive model is explored. The strain and polarization response to calculated for a single crystal subjected to mechanical and electrical loading; the evolution of single crystal yield surfaces is determined. A self-consistent scheme is used in conjunction with the constitutive model to produce estimates of the response of a ferroelectric polycrystal to electrical and mechanical loading. Expressions are derived for self-consistent estimates of the instantaneous tangent properties of a ferroelectric polycrystal. Self-consistent calculations of dielectric hysteresis and "butterfly" hysteresis are compared with experimental measurements made on a commercial Lead Zirconate Titanate ceramic. Predictions of the development of a cornered ferroelectric yield surface under loading are given.

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