High-performance Schottky diodes endure high temperatures

Fabrication process and aluminum/GaAs (gallium arsenide) coupling are used to produce Schottky diodes that have high cutoff frequencies and can withstand operating temperatures in excess of 500 C

Unnatural Conduct & Forced Difficulties: Austen, Reading, and the Paradox of the Feminine Ideal

Though some scholars have maintained that Jane Austen closely adheres to the ideology of courtesy novels and conduct literature, I argue that Austen uses her knowledge of this ideology to reveal the flaws in reader assumptions about the presumed commonsensical nature of the courtesy novel and its feminine ideal. Austen is familiar with the conventions of eighteenth-century fiction, but, rather than adopting its tropes in her own work, she uses realism to parody its excesses and improbabilities; this realism then works against reader expectations and exposes paradoxes inherent in the courtesy novel and in conduct-book literature itself. In my thesis I observe how Austen uses courtesy novel tropes to expose or even mock the courtesy novel\u27s inherently unrealistic qualities, and I do so by examining the act of reading in her novels: specifically, I argue that the literal reading that Austen\u27s characters engage in does not produce the expected outcomes predicted by conduct books and courtesy novels; that the figurative reading of one character by another demonstrates the dangerousness and unsuitability of the heroine as open book, as conduct books and courtesy novels urged her to be, as well as the irrationality and hypocrisy of acting the part of closed book to her intended lover; and, finally, that the act of reading an Austen novel is intended to prevent the absorption or interpretation of unrealistic ideals, through insistence on (more) realistic outcomes and through narrative intervention

Extractable nitrogen and microbial community structure respond to grassland restoration regardless of historical context and soil composition.

Grasslands have a long history of invasion by exotic annuals, which may alter microbial communities and nutrient cycling through changes in litter quality and biomass turnover rates. We compared plant community composition, soil chemical and microbial community composition, potential soil respiration and nitrogen (N) turnover rates between invaded and restored plots in inland and coastal grasslands. Restoration increased microbial biomass and fungal : bacterial (F : B) ratios, but sampling season had a greater influence on the F : B ratio than did restoration. Microbial community composition assessed by phospholipid fatty acid was altered by restoration, but also varied by season and by site. Total soil carbon (C) and N and potential soil respiration did not differ between treatments, but N mineralization decreased while extractable nitrate and nitrification and N immobilization rate increased in restored compared with unrestored sites. The differences in soil chemistry and microbial community composition between unrestored and restored sites indicate that these soils are responsive, and therefore not resistant to feedbacks caused by changes in vegetation type. The resilience, or recovery, of these soils is difficult to assess in the absence of uninvaded control grasslands. However, the rapid changes in microbial and N cycling characteristics following removal of invasives in both grassland sites suggest that the soils are resilient to invasion. The lack of change in total C and N pools may provide a buffer that promotes resilience of labile pools and microbial community structure

Temperature-stable Gunn-diode oscillator

Oscillator consisting of Gunn diode embedded in coaxial circuit has excellent temperature stability and low fabrication costs as compared with automatic-frequency-control crystal oscillators

A Markov chain model to enhanced the weather simulation capabilities of an operations and maintenance tool for a wave energy array

Operations and maintenance is a vital area of research in the push to make wave energy a commercial reality. A tool has previously been developed by Pelamis Wave Power to obtain reliable estimates for operational expenditure and ensure smooth running of wave energy arrays. Wave Energy Scotland is now tasked with the future development of this operations and maintenance tool. One of its key inputs is the wave and wind data used to simulate weather windows suitable for marine access. This paper details the creation and validation of a Markov Chain Model to enhance the weather simulation capabilities of the tool. This will ensure that the operations and maintenance strategy of wave energy arrays is modelled more realistically, resulting in an increased confidence in cost estimates and logistical arrangements.The author would like to thank the academic supervisors of this IDCORE project for their contributions, advice and support. Similar thanks must go to the engineers, past and present, who have dedicated their time to the Pelamis project. The industrial supervisor deserves a special mention, without her experience and guidance this study would not have been a success. The author would also like the IDCORE programme and its funding bodies, in particular the ETP (Energy Technology Partnership), for their support

Topological Ring Currents and Bond Currents in Some Neutral and Anionic Altans and Iterated Altans of Corannulene and Coronene.

The novel series of conjugated systems called altans, defined nearly a decade ago, was subsequently extended to multiple ("iterated") altans, and their magnetic properties were calculated by Monaco and Zanasi using the ab initio ipso-centric formalism. Such properties of the single ("mono") altans of corannulene and coronene, calculated by this sophisticated ab initio approach, had earlier been compared with those calculated via the rudimentary Hückel-London-Pople-McWeeny (HLPM) method-a parameter-free topological, quasi graph-theoretical approach requiring knowledge only of the conjugated system's molecular graph and the areas of its constituent rings. These investigations are here extended to double and triple altans. HLPM bond currents in several neutral mono altans are found to differ from those in the corresponding dianion only in those bonds that lie on the structures' perimeters, while the HLPM bond currents in all bonds in the neutral double and triple altans of corannulene and coronene are precisely the same as in the respective dianions. Some rationalization of these unexpected phenomena is offered in terms of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) nature of the role played by the lone nonbonding orbital in each of the neutral species and its respective dianion

Postscript on Viable Ground-States for Calculating Topological π-Electron Ring-Currents Using the Hückel–London–Pople–McWeeny Model

Attention is drawn to the idea that, in the context of the Hückel–London–Pople–McWeeny (HLPM) approach to π-electron ring-currents, the basic Aufbau process can be mimicked by means of a graph-theoretical algorithm and that the outcome is determined solely by the order of the eigenvalues of the arbitrary molecular-graph representing an extant or hypothetical conjugated system. The Aufbau process usually results in a closed-shell ground-state, but sometimes a unique triplet ground-state arises, sometimes doublets, as well as unique ground-states of higher multiplicity, are encountered, and, on occasions, no uniquely defined π-electronic ground-state is established at all. Previously, the only examples of the latter (‘pathological’) case — which, as with triplet ground-states and other ground-states that are not singlets, precludes the possibility of any HLPM calculation — were graphs that are unlikely candidates for being extant or viable conjugated systems. In this note, however, an example is documented of what is, ostensibly, a plausible unsaturated structure — namely, (Coronene)6–. In the conclusion, attention is drawn to a procedure that averages electron occupation amongst the several orbitals of a degenerate shell. This work is licensed under a Creative Commons Attribution 4.0 International License

Some Observations on Triplet Ground-States in the Context of ‘Topological’ (HLPM) Ring-Currents in Conjugated Systems

When the quasi graph-theoretical Hückel–London–Pople–McWeeny (HLPM) approach is used to calculate ‘topological’ π-electron ring-currents and bond-currents in conjugated hydrocarbons, a problem is identified that occurs whenever application of the Aufbau process gives rise to a π-electronic ground-state configuration that is a triplet. This circumstance seems to occur only occasionally and, even when it does, the generally somewhat outré molecular graphs in question appear unlikely to represent extant or viable conjugated systems. The molecular graphs of four examples are used to illustrate this ‘triplet ground-state problem’, only one of which represents a hydrocarbon that has actually been synthesised. It is pointed out that the ‘triplet ground-state problem’ does constitute an intrinsic limitation of the HLPM approach. It is, though, a limitation that is also necessarily inherent in other equivalent (though ostensibly different) methods of calculating magnetic properties due to π-electron ring-currents — methods that are likewise founded on the Hückel molecular-orbital conventions. When a triplet ground-state arises, topological ring-currents and bond-currents cannot be calculated by the HLPM method and its equivalents. Infinite paramagnetism is formally to be predicted in such situations. This work is licensed under a Creative Commons Attribution 4.0 International License