Efficient analysis of mode profiles in elliptical microcavity using dynamic-thermal electron-quantum medium FDTD method.

The dynamic-thermal electron-quantum medium finite-difference time-domain (DTEQM-FDTD) method is used for efficient analysis of mode profile in elliptical microcavity. The resonance peak of the elliptical microcavity is studied by varying the length ratio. It is observed that at some length ratios, cavity mode is excited instead of whispering gallery mode. This depicts that mode profiles are length ratio dependent. Through the implementation of the DTEQM-FDTD on graphic processing unit (GPU), the simulation time is reduced by 300 times as compared to the CPU. This leads to an efficient optimization approach to design microcavity lasers for wide range of applications in photonic integrated circuits.

Highly sensitive graphene biosensors based on surface plasmon resonance.

A surface plasmon resonance (SPR) based graphene biosensor is presented. It consists of a graphene sheet coated above a gold thin film, which has been proposed and experimentally fabricated recently [ChemPhysChem 11, 585 (2010)]. The biosensor uses attenuated total reflection (ATR) method to detect the refractive index change near the sensor surface, which is due to the adsorption of biomolecules. Our calculations show that the proposed graphene-on-gold SPR biosensor (with L graphene layers) is (1 + 0.025 L) x gamma (where gamma > 1) times more sensitive than the conventional gold thin film SPR biosensor. The improved sensitivity is due to increased adsorption of biomolecules on graphene (represented by the factor gamma) and the optical property of graphene.

A modular implementation of dispersive materials for time-domain simulations with application to gold nanospheres at optical frequencies.

The development of photonic nano-structures can strongly benefit from full-field electromagnetic (EM) simulations. To this end, geometrical flexibility and accurate material modelling are crucial requirements set on the simulation method. This paper introduces a modular implementation of dispersive materials for time-domain EM simulations with focus on the Finite-Volume Time-Domain (FVTD) method. The proposed treatment can handle electric and magnetic dispersive materials exhibiting multi-pole Debye, Lorentz and Drude models, which can be mixed and combined without restrictions. The presented technique is verified in several illustrative examples, where the backscattering from dispersive spheres is calculated. The amount of flexibility and freedom gained from the proposed implementation will be demonstrated in the challenging simulation of the plasmonic resonance behavior of two gold nanospheres coupled in close proximity, where the dispersive characteristic of gold is approximated by realistic values in the optical frequency range.

Vocational aspirations of sheltered workshop workers with intellectual disability in Hong Kong.

In Hong Kong, the understanding of the vocational experience of sheltered workshop workers with intellectual disability is still relatively meagre. Twenty-three participants with intellectual disability and four professionals from their sheltered workshops were interviewed using mainly open-ended questions. Content analysis and constant comparative method were adopted to categorize the descriptive data into themes that were salient to the participants' vocational aspirations to try open employment. The insider perspective showed that all participants were motivated to have employment. Thirteen participants with intellectual disability preferred to try open employment and they had individual vocational preferences which mainly belonged to unskilled and manual work. The professionals pointed out that sheltered workshop workers with intellectual disability needed professionals' assistance and parents' consent in moving on to open employment, and parents were the key people in this decision-making process. These findings indicate that sheltered workshop workers with intellectual disability have limited self-determination in the work arena. The need to empower people with intellectual disability, improve the quality of sheltered employment services and increase the involvement of their family members are discussed.

Exploring self-concepts of persons with brain injury.

BACKGROUND: This study explored the self-concepts of Hong Kong Chinese adults with brain injury. OBJECTIVES: The Adult Source of Self-concept Inventory (ASSEI) Chinese Version was adopted to identify the sources and basis of the self-conceptions of 120 persons with brain injury. METHOD: The Adult Source of Self-Esteem Inventory (ASSEI), a self evaluation tool using open-ended questions and interviewing, was used to identify the sources and basis of the self-concept of persons with and without brain injury. The subjects' important life aspects were identified through interpreting their responses to open-ended questions and interviews. Moreover, a structured questionnaire on their subjective perceptions of importance and satisfaction in different life areas was used to identify the relationships between discrete self-concept variables. The subjects' responses to the 20 items of the ASSEI were also subjected to an exploratory factor analysis. MAIN OUTCOME AND RESULTS: Five self-concept related factors, which accounted for 65.55% of the total variance, were successfully identified. They were family self, physical self, moral self, personal achievement and social self. The self-concept factors match the results of content analysis of the subjects' responses to the open-ended questions. The results showed that family, physical health, work and friends were the most important domains in lives of individuals with brain injury. Brain injury survivors felt good towards their family, work and friends in their daily life. However, the majority expressed the view that they felt bad due to deteriorating physical health, poor family relationships, emotional difficulties and poor working relationship with others. CONCLUSION: Findings from this study identified the self-concept basis of persons with brain injury that can indicate self-concept enhancement strategies to improve their rehabilitation outcomes. Hopefully, they can develop more positive self-images and, thus, achieve better community integration.