First principle study of Mg, Si and Mn co-doped GaN

Calculations of electronic structures and optical properties of Mg (or Si) and Mn co-doped GaN were carried out by means of first-principle plane-wave pesudopotential (PWP) based on density functional theory - The spin polarized impurity bands of deep energy levels were found for both systems. They are half metallic and suitable for spin injectors. Compared with GaN Mn, GaN Mn-Mg exhibits a significant increase in T-C 1 while the 1.3 eV absorption peak in GaN Mn disappears due to addition of Mg. In addition, a strong absorption peak due to T-4(1) (F) -> T-4(2) (F) transition of Mn4+ were observed near 1.1 eV. Nevertheless, GaN Mn-Si failed to show increase of T-C, and the absorption peak was not observed at the low energy side.

Program: a record of the first 40 years of electronic library and information systems

Tedd, L.(2006). Program: a record of the first 40 years of electronic library and information systems. Program: electronic library and information systems,40(1), 11-26.

Living with Jesus: Practical Christologies in Two Boston American Baptist Churches

This dissertation, an exercise in practical theology, undertakes two tasks. First, it examines how the story of Jesus is appropriated and embodied in the corporate practices of worship and mission (congregational christology) and in the daily lives of ordinary believers (everyday christology) at First Baptist Church in Jamaica Plain and Ruggles Baptist Church in Boston, Massachusetts. Second, it places these practical christologies in dialogue with the academic christology of James McClendon to see what creative and critical insights emerge. A key assumption of the study is that doctrinal reflection is precipitated when the story of Jesus interacts with human stories in both autobiographical and public domains. "Living with Jesus" contends that the understandings of Jesus present in the everyday lives of believers and in a congregation's worship and mission merit the attention of scholars in the disciplines of sociology and theology. This dissertation demonstrates that scholarly research on the visible church, everyday religion, and Christian doctrine pays limited attention to the theologies operative in the everyday lives of believers and congregational practices. A gap exists in scholarly knowledge, which "Living with Jesus" attempts to redress. The empirical results of qualitative research fieldwork are set in the context of historical overviews and contemporary snapshots of First Baptist Church in Jamaica Plain and Ruggles Baptist Church. "Living with Jesus" identifies three types of practical christology operative across the two congregations in corporate practices and the everyday lives of individuals: evangelical christology; exemplarist christology; and prophetic christology. The empirical research shows that for a significant minority of people in the sample, the prevailing understanding of Jesus can best be described as a hybrid christology. By paying attention to McClendon's treatment of the Jesus story and placing the three identified practical christologies in dialogue with his christology, it becomes apparent that each practical christology is simultaneously liberating and limiting. This dissertation argues that evaluating a particular practical christology in relation to the Gospel requires an intentional and disciplined effort on the part of congregations, ordinary believers, and theologians. Questions are proposed to assist further christological reflection on worship, mission, pastoral care, and Christian education.

Investigation of numerical atomic orbitals for first-principles calculations of the electronic and transport properties of silicon nanowire structures

This thesis is focused on the application of numerical atomic basis sets in studies of the structural, electronic and transport properties of silicon nanowire structures from first-principles within the framework of Density Functional Theory. First we critically examine the applied methodology and then offer predictions regarding the transport properties and realisation of silicon nanowire devices. The performance of numerical atomic orbitals is benchmarked against calculations performed with plane waves basis sets. After establishing the convergence of total energy and electronic structure calculations with increasing basis size we have shown that their quality greatly improves with the optimisation of the contraction for a fixed basis size. The double zeta polarised basis offers a reasonable approximation to study structural and electronic properties and transferability exists between various nanowire structures. This is most important to reduce the computational cost. The impact of basis sets on transport properties in silicon nanowires with oxygen and dopant impurities have also been studied. It is found that whilst transmission features quantitatively converge with increasing contraction there is a weaker dependence on basis set for the mean free path; the double zeta polarised basis offers a good compromise whereas the single zeta basis set yields qualitatively reasonable results. Studying the transport properties of nanowire-based transistor setups with p+-n-p+ and p+-i-p+ doping profiles it is shown that charge self-consistency affects the I-V characteristics more significantly than the basis set choice. It is predicted that such ultrascaled (3 nm length) transistors would show degraded performance due to relatively high source-drain tunnelling currents. Finally, it is shown the hole mobility of Si nanowires nominally doped with boron decreases monotonically with decreasing width at fixed doping density and increasing dopant concentration. Significant mobility variations are identified which can explain experimental observations.

SrTiO3(001)(2x1) reconstructions: First-principles calculations of surface energy and atomic structure compared with scanning tunneling microscopy images

(1x1) and (2x1) reconstructions of the (001) SrTiO3 surface were studied using the first-principles full-potential linear muffin-tin orbital method. Surface energies were calculated as a function of TiO2 chemical potential, oxygen partial pressure and temperature. The (1x1) unreconstructed surfaces were found to be energetically stable for many of the conditions considered. Under conditions of very low oxygen partial pressure the (2x1) Ti2O3 reconstruction [Martin R. Castell, Surf. Sci. 505, 1 (2002)] is stable. The question as to why STM images of the (1x1) surfaces have not been obtained was addressed by calculating charge densities for each surface. These suggest that the (2x1) reconstructions would be easier to image than the (1x1) surfaces. The possibility that the presence of oxygen vacancies would destabilise the (1x1) surfaces was also investigated. If the (1x1) surfaces are unstable then there exists the further possibility that the (2x1) DL-TiO2 reconstruction [Natasha Erdman Nature (London) 419, 55 (2002)] is stable in a TiO2-rich environment and for p(O2)>10(-18) atm.

Church of St George and St Thomas

Abstract: A vibrant inner city parish needed space for meetings, language classes, children’s play and other support accommodation as well as a clearer link between the interior of the listed church and the space outside.

The project builds itself about the entrance to the church. The form is manipulated such that the intervention recedes from those entering the church, drawing them into the plan before becoming readable as an addition. The resultant poché between this entrance sequence and the fabric of the church is hollowed out to provide the required accommodation. These rooms are insulated and lined in cork to allow for their use separate to the main body of the church. With budget at a premium the construction methodology was developed from an analysis of traditional Irish boat building techniques, which allowed the use of the solid timber to act as the primary structure with no additional material support.

Constructed in solid walnut the intervention reads with the existing brick interior and yet is clearly identifiable as a contemporary addition.

Aims / Objectives Questions

1 To accommodate new space inside an existing protected structure.
2 To form a new threshold between interior and exterior.
3 To develop an affordable means of construction that would be durable and rapid to erect.
4 To make a contemporary addition in sympathy with the qualities of the existing protect structure, in line with best conservation practice and research.
5 Traditional forms of construction as a model for contemporary technologies.

Additional Accommodation Church of St George and St Thomas

A vibrant inner city parish needed space for meetings, language classes, children’s play and other support accommodation as well as a clearer link between the interior of the listed church and the space outside.

The project builds itself about the entrance to the church. The form is manipulated such that the intervention recedes from those entering the church, drawing them into the plan before becoming readable as an addition. The resultant poché between this entrance sequence and the fabric of the church is hollowed out to provide the required accommodation. These rooms are insulated and lined in cork to allow for their use separate to the main body of the church. With budget at a premium the construction methodology was developed from an analysis of traditional Irish boat building techniques, which allowed the use of the solid timber to act as the primary structure with no additional material support.

Constructed in solid walnut the intervention reads with the existing brick interior and yet is clearly identifiable as a contemporary addition.

Aims / Objectives Questions

1 To accommodate new space inside an existing protected structure.
2 To form a new threshold between interior and exterior.
3 To develop an affordable means of construction that would be durable and rapid to erect.
4 To make a contemporary addition in sympathy with the qualities of the existing protect structure, in line with best conservation practice and research.
5 Traditional forms of construction as a model for contemporary technologies.


Principal Investigator: Clancy Moore Architects –Colm Moore

Co-investigator(s): Andrew Clancy, Mathew O’Malley

Funding partner/ Client: Select Vestry of St George and St Thomas

Finance. €35’000

Date (start – finished) Start June 2008 – Completed December 2008

A Damascene Conversion:Additional Accommodation Church of St George and St Thomas

Additional Accommodation Church of St George and St Thomas - Critical Appraisal ‘A Damascene Conversion’ by Shane O’Toole in The Sunday Times December 2008.