the possibility of terahertz generation has been investigated from a photoconductive switch based on gaas, gated by a femtosecond laser. the emission properties of photoconductive antenna (pca) with low-temperature-grown (lt) gaas have been studied. in such gaas materials presence of the charged defects induces a redistribution of the electric field between the antenna electrodes. this effect h...

The role of foot-and-mouth disease virus (FMDV) carrier cattle in causing new outbreaks is still a matter of debate and it is important to find out these carrier animals by post-outbreak serosurveillance to declare freedom from FMDV infection. In this study we explore the differences in viral shedding between carrier and non-carrier animals, quantify the transmission rate of FMDV infection from...

OFDM is a multicarrier modulation technique in which a high rate bitstream is split into N parallel bit-streams of lower rate and each of these are modulated using one of N orthogonal sub-carriers. Orthogonal Frequency Division Multiplexing (OFDM) is an emerging multi-carrier modulation scheme, which has been adopted for several wireless standards such as IEEE 802.11a and HiperLAN2. In a basic ...

This paper deals with the effects of mixing time on the homogeneity and dispersion performance of adhesive mixtures for inhalation. Interactions between these effects and the carrier size fraction, the type of drug and the inhalation flow rate were studied. Furthermore, it was examined whether or not changes in the dispersion performance as a result of prolonged mixing can be explained with a b...

The UNSW node of the Hot Carrier Solar Cell project is investigating absorbers which slow the rate of carrier cooling an essential element of a successful cell. It has also further developed the work on energy selective contacts for Hot Carrier cells. This work includes modelling the limiting efficiencies of cells using real material properties and modelling the phonon dispersions of ordered ar...

Multi-carrier modulation (MCM) techniques are used for high bit rate data transmission in radio transmission systems. The main scope of this work includes understanding a multi-carrier modulation system and setting up a simulation environment for such a system as applied in the case of Asymmetric Digital Subscriber Loop (ADSL) system and Orthogonal Frequency Division Multiplex (OFDM) system. Th...

In this work the effect of carrier gas and post-growth activation conditions on the electrical properties of Mg-doped p-GaN single layers grown in a vertical flow close-coupled showerhead MOCVD system is investigated. The results of Hall effect measurements show that although the optimal Mg precursor flow rate depends on the growth atmosphere and is smaller when N2 is used as a carrier gas, sim...

We investigate the transient photoconductivity of graphene at various gate-tuned carrier densities by optical-pump terahertz-probe spectroscopy. We demonstrate that graphene exhibits semiconducting positive photoconductivity near zero carrier density, which crosses over to metallic negative photoconductivity at high carrier density. These observations can be accounted for by the interplay betwe...

Time-resolved photoluminescence and four-wave mixing techniques have been combined for studies of carrier relaxation dynamics in a highly photoexcited GaN epilayer. For a moderate excitation density below 1 mJ/cm, carrier recombination was due to free carrier capture by deep traps. The characteristic time of carrier capture, τe = 550 ps, was measured under deep trap saturation regime. The ambip...

The e_ff~ct of l_ateral carrier diffusion upon the modulation characteristics of the semiconductor laser ts mvest~gated. ~ self-consistent analysis of the spatially dependent rate equations is performed usmg a fim~e ele_ment model. The transverse junction stripe laser is treated as an exam~le and a co~panson ts made between lateral carrier diffusion and spontaneous emission as dampmg ~echamsms ...