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(2000)Journal ArticleBi1.7Pb0.3Sr2Ca2Cu3O10+y was used as an example of Cuprates for our study. The subtle thermal transitions and the jumps of the parameters appear in the sample at about 300 and 700oC, respectively. The unit cell of the sample is composed of two structural blocks: perovskite and rock salt. The size of every block along c direction is about a nanometer. What should be made clear is whether the two thermal and structural changes take place in the whole cell or from different blocks. The bond lengths in the unit cell are analyzed carefully before and after two thermal and structural changes based on the results of X-ray diffraction. Careful analysis of the bond length in the samples demonstrates that the two jumps of the parameters are correlated with the two blocks. After the jump at about 300oC, the bond lengths in the rock salt block change more significant than in the perovskite block. After the jump at about 700oC, the bond lengths in the perovskite block change more significant than in the rock salt block. The change of the bond lengths clearly shows that the different thermal transitions and the jumps of the parameters take place in different blocks.
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(2000)Journal ArticleBased on a block model, separating the unit cell of YBa2Cu3O7-[delta] into perovskite and rock salt blocks, the combinative energy between the two blocks in the YBa2Cu3O7-[delta] with the different [delta] value, from 0.07 to 0.62, was calculated. A close relationship between the superconducting transition temperature and the combinative energy in YBa2Cu3O7-[delta] is established, and the change of the combinative energy is closely related to the transformation from orthorhombic I to II. The results also give a clue to reconsider the role of the orthorhombic I and II in YBa2Cu3O7-[delta]. The calculation of the holes in different planes supplies abundant information about the charge distribution in YBa2Cu3O7-[delta], which may possibly connect the electronic phase diagram and the fluctuations of the stripe phase. The results show that the interaction between the two blocks is of great importance for high Tc superconductivity.
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(1999)Journal ArticleThe influence of the flux flow on a.c. loss and magnetic penetration process in superconductors has been investigated. Asymptotic solutions of magnetic and electric fields and a.c. loss are presented in the form of a power series of [Lambda], the normalized frequency of the external a.c. magnetic field. The results show that the flux flow retards the response of inner magnetic field to the external one, which results in a deviation from the critical state model and a non-hysteretic loss. In the cases of H0>Hp, the deviation from the critical state is in the order of the second power of [Lambda]. The induced electric field and the macro-penetration depth are decreased by the slowdown of the flux movement, giving a negative contribution to the a.c. loss. However, the negative contribution is compensated by the increase of the current density, leading to a net increase of the a.c. loss. As a result, the a.c. loss exhibits a positive dependence on the frequency and the amplitude of the external magnetic field.
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(1999)Journal ArticleLow-temperature thermal expansion and its correlation with oxygen nonstoichiometry have been studied for Bi1.7Pb0.3Sr2Ca2Cu3O10+y samples. An anomalously big jump of the thermal expansion in the c direction of Bi1.7Pb0.3Sr2Ca2Cu3O10+y has been observed at a temperature slightly above the superconductivity transition temperature. The corresponding temperature and the magnitude of the jump are found to be correlated with the oxygen nonstoichiometry, carrier concentration and superconductivity. The results reveal that the anomalously big jump of the thermal expansion is an electron-assisted lattice softening transition. Its correlation with the superconductivity suggests that phonon-electron interaction still plays a certain role in the superconductivity in high-Tc cuprates.
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(1998)Journal Article
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(1998)Journal ArticleThe vortex-glass-liquid transition in Bi---Sr---Ca---Cu---O (BSCCO) intergrowth single crystals in which some CuO2 trilayers are inserted into the Bi2Sr2CaCu2O8 matrix has been studied. The curvature of the log V-logI curves for CuO2 trilayers is found to change from negative to positive with increasing magnetic field and a scaling behaviour for the vortex-glass state is observed. The magnetic field dependence of the vortex-glass transition temperature, TG, qualitatively obeys the relation H(TG) (Tc − Tg)2v0, with v0 = 1.15 ± 0.2, which is larger than the 2/3 predicted theoretically for an isotropic 3D system. Our results reveal that the vortex-glass transition exists in a system constructed with CuO2 trilayers.
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(2009)Conference PaperA raft of models and definitions of SoTL exist and the best appear to transcend disciplinary contexts, and are sufficiently robust for academics to measure scholarly practices. Critical engagement with the scholarly literature is necessary for academics to gain a realistic view of where their work practices are situated within the scholarly domain. Because academic staff are disciplinary experts they are best placed to comment on whether the models of scholarship describe the scholarship of learning and teaching within the context of their own disciplines as well as within the confines of the Australian higher education sector. This paper pushes the existing debates on reconciling what evidence of scholarship in the disciplines actually is and what is considered valid, and in doing so uncovers why the process of reconciliation, between current practice and supporting evidence, remains elusive. Higher education academics need to identify and reconcile tacit disciplinary knowledge with their SoTL approach in order to unpack the complexity and value of their practices. Enabling academic staff to annotate their activities, roles and accomplishments and then map these items onto the various models of scholarship will enrich the status of scholarship of teaching and learning within the higher education sector.
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(2022)ThesisUnderstanding product semantics and affective perceptions of product consumers undoubtedly offer significant value for industrial designers and their design practice. Deconstructing affective perceptions is a methodologically challenging task as it is implicit and subjective and is influenced by an individual’s aesthetic experience. Accordingly, how products are perceived differs among individuals or consumers, particularly in the distinct experiences that contribute to constructing an individual’s sense of perception of self or self-concept. Furthermore, research has shown that individuals are implicitly drawn to products that reaffirm and communicate their self-concept. If an individual’s preferences for products can reflect or enhance their self-concept, this suggests that understanding the underlying perceptual processes between the self-concept and product semantics can productively inform industrial design research. The thesis research develops and adapts methods from the disciplines of psychology, marketing, and industrial design to investigate these underlying perceptual processes of the self-concept and its relationships to product semantics. The thesis research investigates the underlying processes through a study on kettles that discloses the variances in sensory and cognitive evaluation and judgements through the process of aesthetic experience. The thesis further investigates the cognitive influences of the self-concept to reveal the mental models associated with the visual aesthetics of product form and how this influences aesthetic responses through product personality congruence. The thesis argues that the self-concept is a multidimensional construct reflected, in particular, through an individual’s (1) gender identity, (2) personality, (3) aesthetic sensitivity, and (4) interest, taste, and goals, that plays a vital role in the aesthetic experience of products. The thesis’s findings indicate that these individual components of the self-concept are essential in that they interplay in how the symbolic meaning of product semantics is visually perceived. The outcome of this thesis assists in, primarily, revealing the underlying stages of visual aesthetic processing to understand how product semantics is perceived through an individual’s self-concept.