Charge Density Wave Instability and Soft Phonon in AAPt3_3P (AA=Ca, Sr, and La)

The electronic and phonon properties of the platinum pnictide superconductors $A$Pt$_3$P ($A$=Ca, Sr, and La) were studied using first-principles calculations. The spin-orbit coupling effect is significant in LaPt$_3$P but negligible in CaPt$_3$P and SrPt$_3$P, although they all share the same anti-pevroskite structure. Moreover, SrPt$_3$P has been demonstrated to exhibit an unexpected weak charge-density-wave(CDW) instability which is neither simply related to the Fermi-surface nesting nor to the momentum-dependent electron-phonon coupling alone. The instability is absent in CaPt$_3$P and can be quickly suppressed by the external pressure, accompanied with gradual decreases in the phonon softening and BCS $T_c$. Our results suggest SrPt$_3$P as a rare example where superconductivity is enhanced by the CDW fluctuations

Two-Step Sintering of Ceramics with Constant Grain-Size, I. Y\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e

Isothermal and constant-grain-size sintering have been carried out to full density in Y2O3 with and without dopants, at as low as 40% of the homologous temperature. The normalized densification rate follows Herring’s scaling law with a universal geometric factor that depends only on density. The frozen grain structure, however, prevents pore relocation commonly assumed in the conventional sintering models, which fail to describe our data. Suppression of grain growth but not densification is consistent with a grain boundary network pinned by triple-point junctions, which have a higher activation energy for migration than grain boundaries. Long transients in sintering and grain growth have provided further evidence of relaxation and threshold processes at the grain boundary/triple point

Single Impurity In Ultracold Fermi Superfluids

The role of impurities as experimental probes in the detection of quantum material properties is well appreciated. Here we study the effect of a single classical magnetic impurity in trapped ultracold Fermi superfluids. Depending on its shape and strength, a magnetic impurity can induce single or multiple mid-gap bound states in a superfluid Fermi gas. The multiple mid-gap states could coincide with the development of a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase within the superfluid. As an analog of the Scanning Tunneling Microscope, we propose a modified RF spectroscopic method to measure the local density of states which can be employed to detect these states and other quantum phases of cold atoms. A key result of our self consistent Bogoliubov-de Gennes calculations is that a magnetic impurity can controllably induce an FFLO state at currently accessible experimental parameters.Comment: 5 pages, 3 figures; added calculations for 3

Long-Term Monitoring of Slope Movements with Time-Domain Reflectometry Technology in Landslide Areas, Taiwan

The study employs time-domain reflectometry (TDR) technology for landslide monitoring to explore rock deformation mechanism and to estimate locations of potential sliding surfaces in several landslide areas, Taiwan, over ten years. Comparing to laboratory and field testing, sliding surfaces in landslide areas occurred mainly at two types, namely shear and extension failure. The TDR technology is used for field monitoring to analyze locations of sliding surfaces and to quantify the magnitude of the sliding through laboratory shear and extension tests. There are several TDR-monitoring stations in six alpine landslide areas in the middle of Taiwan for long-term monitoring. A relation between TDR reflection coefficients and shear displacements was employed for a localized shear deformation in the field. Furthermore, the type of a cable rupture for the TDR monitoring in landslides can be determined as shear, extension, or compound failure through the field TDR waveforms. Overall, the TDR technology is practically used for a long-term monitoring system to detect the location and magnitude of slope movement in landslide areas

Working and Learning Together: The Lived Experiences of Further Education Teachers Engaging with Joint Practice Development as a Model of Collaborative Enquiry for Professional Learning

This thesis narrates the lived experiences of a practitioner-led participatory action research study that explores the implementation of Joint Practice Development (JPD) (Gregson et al., 2013) to collaborate with further education (FE) college teachers in professional learning. Inspired by the work of Fielding et al. (2005) and Hargreaves (2012) and recommended by Coffield (2017), the JPD model provides teacher-centred, collaborative professional learning at the heart of this thesis. Little is known about how JPD is integrated in practice in the FE context. Consequently, this research contributes to a small body of collaborative professional learning studies in FE and offers particular insights arising from the rich accounts of the experience of six FE teachers’ engagement and my own as a JPD facilitator and member of the learning community. The study takes an interpretivist approach and represents the holistic view that human beings are able to construct and reconstruct meaning through social interactions (Dewey, 1938/1997). Through narrative inquiry-based research methods (Connelly and Clandinin, 1990; Kim, 2015), interviews, JPD workshops, artefacts, field notes and a research diary are used to record and interpret the experiences of both myself and participants working, learning and reflecting together to develop and enhance aspects of teaching, learning and assessment. A three-dimensional narrative inquiry framework is used to interpret and narrate the messy trajectories of building this learning community together as we move and meld participants’ and researcher’s perspectives into one coherent research account. The finding of this study suggests that top down and one off continuing professional development (CPD) rarely meets teachers’ professional learning needs. JPD provides an alternative democratic approach to cultivate, nurture and sustain professional learning communities that care and value teachers’ professionalism and support them to take ownership of their learning in situated contexts. Additionally, the social and emotional dimensions of collaborative professional learning vital to JPD lays the foundation for trusting relationships that encourage reflective dialogues and reflexivity. A reconceptualised model of JPD is developed building on the initial framework designed by Gregson et al. (2015b). There is much scope for FE sector organisations to integrate policy that supports and encourages teacher-led, collaborative approaches to professional learning. Further research is welcomed which explores experiences of collaborative professional learning such as JPD both in the FE context and other education contexts including Higher Education and schools