ANU Scholarly Output
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The Australian National University's Scholarly output collection is an online location for collecting, preserving and disseminating the scholarly output of the University. This service allows members of the University to share research with the wider community. ANU Open Research accepts journal articles, conference papers, book chapters, working or technical papers and other forms of scholarly communication.
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Item Open Access 0-π phase transition in hybrid superconductor-InSb nanowire quantum dot devices(American Physical Society, 2016-12-30) Li, S.; Kang, N.; Caroff, P.; Xu, H. Q.Hybrid superconductor-semiconducting nanowire devices provide an ideal platform to investigating interesting intragap bound states, such as the Andreev bound states (ABSs), Yu-Shiba-Rusinov (YSR) states, and the Majorana bound states. The competition between Kondo correlations and superconductivity in Josephson quantum dot (QD) devices results in two different ground states and the occurrence of a 0-π quantum phase transition. Here we report on transport measurements on hybrid superconductor-InSb nanowire QD devices with different device geometries. We demonstrate a realization of continuous gate-tunable ABSs with both 0-type levels and π-type levels. This allow us to manipulate the transition between the 0 and π junction and explore charge transport and spectrum in the vicinity of the quantum phase transition regime. Furthermore, we find a coexistence of 0-type ABS and π-type ABS in the same charge state. By measuring temperature and magnetic field evolution of the ABSs, the different natures of the two sets of ABSs are verified, being consistent with the scenario of phase transition between the singlet and doublet ground state. Our study provides insight into Andreev transport properties of hybrid superconductor-QD devices and sheds light on the crossover behavior of the subgap spectrum in the vicinity of the 0-π transition.Item Embargo 1 H NMR studies of enantioselective host-guest complexation by modified β-cyclodextrins and their europium(III) complexes(Pergamon-Elsevier Ltd, 2008) Pham, Duc-Truc; Clements, Philip; Easton, Christopher; Lincoln, Stephen FThe enantioselectivity of mono-substituted β-cyclodextrins 6A-[bis(carboxylatomethyl)amino]-6A-deoxy-β-cyclodextrin, 6βCDidaH2, (2AS,3AS)-3A-[bis(carboxylatomethyl)amino]-3A-deoxy-β-cyclodextrin, 3βCDidaH2, 6A-[tris(carboxylatomethyl)(2-aminoethyl)amItem Embargo 1 L a and 1 L b States of Indole and Azaindole: Is Density Functional Theory Inadequate?(American Chemical Society, 2012) Arulmozhiraja, Sundaram; Coote, MichelleThe applicability of time-dependent density functional theory (TD-DFT) is tested in describing1La and1Lb π-π*states in indole, azaindole, indene, and benzimidazole. Several density functionals including popular three hybrid functionals (B3LYP, PBE0, andItem Embargo (1 R ,2 R )-1-(2-Bromo-4-hydroxy-3,5-dimethoxyphenyl)-2,3-dihydroxypropanol(Munksgaard International Publishers, 2007) Chand, Satish; Willis, AnthonyThe title compound, C11H15BrO6, is enanti-omerically pure and the chirality at C-1 and C-2 was determined to be R in each case. The chirality at the stereogenic centres was installed via a Sharpless asymmetric dihydroxy-lation reaction. The crystal structure contains O - H⋯O hydrogen bonds.Item Embargo (1 S ,2 S )-1-(2-Bromo-4-hydroxy-3,5-dimethoxyphenyl)propane-1,2,3-triol(Munksgaard International Publishers, 2007) Chand, Satish; Willis, AnthonyThe title compond, C11H15BrO6, is enanti-omerically pure. The chirality at the stereogenic centres was installed via a Sharpless asymmetric dihydroxy-lation reaction and was determined to be S in each case. The crystal structure contains inter-molecular hydrogen-bonding inter-actions.Item Open Access 1 μm Excess Sources in the UKIDSS. I. Three T Dwarfs in the Sloan Digital Sky Survey Southern Equatorial Stripe(University of Chicago Press, 2011) Matsuoka, Y; Peterson, Bruce; Murata, K. L; Fujiwara, M; Nagayama, T; Suenaga, T; Furusawa, K; Miyake, N; Omori, K; Suzuki, D; Wada, KWe report the discovery of two field brown dwarfs, ULASJ0128-0041 and ULASJ0321+0051, and the rediscovery of ULASJ0226+0051 (IfA 0230-Z1), in the Sloan Digital Sky Survey (SDSS) southern equatorial stripe. They are found in the course of our follow-up observation program of 1μm excess sources in the United Kingdom Infrared Telescope Infrared Deep Sky Survey. The Gemini Multi-Object Spectrographs spectra at red optical wavelengths (6500-10500) are presented, which reveal that they are early-Tdwarfs. The classification is also supported by their optical to near-infrared colors. It is noted that ULASJ0321+0051 is one of the faintest currently known Tdwarfs. The estimated distances to the three objects are 50-110pc, thus they are among the most distant field Tdwarfs known. The dense temporal coverage of the target fields achieved by the SDSS-II Supernova Survey allows us to perform a simple time-series analysis of the dwarfs. We create stacked images of each year from 2002-2007 and find significant proper motions of 150-290masyr-1 or transverse velocities of 40-100kms-1 for ULASJ0128-0041 and ULASJ0226+0051. We also find that there are no detectable, long-term (a-few-year) brightness variations above a few times 0.1mag for the two brown dwarfs.Item Embargo 1,1-Bis(N-methylimidazole)-2-(trimethylsilyl)-1-boracyclohexa-1,4-diene chloride: a stable intermediate or tangent en route to 1-(N-methylimidazole)borabenzene?(American Chemical Society, 2012) Cade, Ian; Hill, AnthonyThe reaction of 1-chloro-2-(trimethylsilyl)-1-boracylohexa-2,5-diene (1) with N-methylimidazole (NMI) results not in the anticipated borabenzene adduct [(NMI)→BC5H5] (3) but rather the title imidazole-stabilized cyclic boronium salt [(NMI)2BC5H5SiMe3-2]Item Embargo 1,1-Divinylallene(Wiley-VCH Verlag GMBH, 2011) Cergol, Katie; Newton, Christopher; Lawrence, Andrew; Willis, Anthony; Paddon-Row, Michael; Sherburn, MichaelHow to hit a triple: The title hydrocarbon, one of the most π-bond-rich small molecules, has been synthesized and characterized for the first time. This highly reactive hydrocarbon undergoes a new diene-transmissive, triple Diels-Alder cycloaddition sequItem Embargo 1,2-Addition versus homoconjugate addition reactions of indoles and electron-rich arenes to alpha-cyclopropyl N-acyliminium ions: synthetic and computational studies(Royal Society of Chemistry, 2019) Ryder, Gregory; Wille, Uta; Willis, Anthony; Pyne, Stephen GAn investigation of the reactivity of α-cyclopropyl N-acyliminium ions towards indoles has resulted in the unprecedented synthesis of 5-cyclopropyl-5-(3-indoyl)pyrrolidin-2-ones via 1,2-addition reactions and, in the case of highly electron deficient indoles and electron rich arenes, spiroheterocycles via sequential homoconjugate and 1,2-addition reactions with often high diastereoselective control at the C-5 quaternary stereocentres. Computational studies provided support for the proposed mechanisms and stereochemical outcome of these reactions, clearly showing that the 1,2-addition pathway is kinetically controlled. In reactions where the 1,2-adduct is destabilised, for example when the arene ring is less nucleophilic, the 1,2-addition is reversible and the thermodynamically preferred homoconjugate addition and subsequent rearrangement and cyclisation reactions become the major pathway.Item Embargo 1,2-Diketones as photoinitiators of both cationic and free-radical photopolymerization under UV (392 nm) or Blue (455 nm) LEDs(Wiley Online Library, 2020) Zhang, Jing; Wang, Shuhui; Lalevee, Jacques; Morlet-Savary, Fabrice; Lam, Elizabeth; Graff, Bernadette; Liu, Jing; Xing, Feiyue; Xiao, PuThe photoinitiation abilities of three 1,2-diketones [i.e., acenaphthenequinone (ANPQ), aceanthrenequinone (AATQ), and 9,10-phenanthrenequinone (PANQ)]-based photoinitiating systems [PISs, with additives such as iodonium salt, N-vinylcarbazole (NVK), tertiary amine, and phenacyl bromide (R-Br)] for cationic photopolymerization and free-radical photopolymerization under the irradiation of ultraviolet (UV; 392 nm) or blue (455 nm) light-emitting diode (LED) bulb are investigated. All 1,2-diketones studied exhibit ground state absorption that match with the emission spectra of UV (392 nm) or blue LED (455 nm) better than that of the well-known blue-light-sensitive photoinitiator camphorquinone (CQ). In particular, AATQ/iodonium salt/NVK can show high photoinitiating ability (with epoxide conversion yield >70%) under the UV light irradiation due to the effect of NVK. In addition, 1,2-diketone/iodonium salt (and optional NVK) systems are capable of initiating free-radical photopolymerization of methacrylates, with conversions of 50–58%. Furthermore, some 1,2-diketone/tertiary amine (and optional R-Br) combinations are found to demonstrate high efficiency to initiate free-radical photopolymerization, and 71% of methacrylate conversion can be achieved with PANQ/tertiary amine/R-Br PIS. Some 1,2-ketone-based PISs can even exhibit higher efficiency than the CQ-based systems. The photochemical mechanism of the radical generation from the 1,2-diketone-based PISs is investigated and found to be consistent with the related photopolymerization efficiency. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 792–802Item Embargo 1,3,5-Benzene-tri-p-phenylphosphonic acid. A new building block in supramolecular chemistry(American Chemical Society, 2008) Beckmann, Jens; Ruttinger, Roman; Schwich, TorstenBenzene-1,3,5-tri-p-phenylphosphonic acid, 1,3,5-[p-C6H 4P(O)(OH)2]3C6H3, (8), a novel building block for applications in supramolecular chemistry, was prepared in two steps with an overall yield of 82%. The [Pd(PPh3) 4]-catalyzed Arbuzov reaction of 1,3,5-tris(p-bromophenyl)benzene with P(Oi-Pr)3 afforded benzene-1,3,5-tri-p-phenylphosphonic diisopropyl ester, 1,3,5-[p-C6H4P(O)(Oi-Pr) 2]3C6H3 (9). The hydrochloric acid-catalyzed hydrolysis of 9 produced 8, which forms a crystalline salt with p-dimethylaminopyridine (DMAP) in a ratio of 2:3 (as methanol solvate) that was characterized by X-ray crystallography. The supramolecular structure features organic domains of stapled 1,3,5-triphenylbenzene units associated by PO-H⋯OP hydrogen bonds and π-stacking. These staples are horizontally cross-linked by PO-H⋯OP hydrogen bonds. The protonated DMAP molecules fill the voids between the staples and participate in the stabilization of the framework by formation of N-H⋯OP hydrogen bonds. The melting point of the adduct (381 °C) confirms the high thermal stability of the supramolecular framework.Item Open Access 1,3,5-Triaryl-1,3,5-Triazinane-2,4,6-Trithiones: Synthesis, Electronic Structure and Linear Optical Properties(Molecular Diversity Preservation International, 2020) Rabouel, Ismaël; Richy, Nicolas; Amar, Anissa; Boucekkine, Abdou; Roisnel, Thierry; Mongin, Olivier; Humphrey, Mark; Paul, FredericThe synthesis of four new 1,3,5-triaryl-1,3,5-triazinane-2,4,6-trithione derivatives (thioisocyanurates) and two new partially thionated analogues from the corresponding 1,3,5-triaryl-1,3,5-triazinane-2,4,6-triones (isocyanurates) is reported, together with their spectroscopic properties. DFT calculations and comparison with the corresponding isocyanurates evidence the impact of the oxygen-for-sulfur replacement on the electronic structure and linear optical properties of these heterocycles. A bathochromic shift of the absorption bands and more efficient quenching of the fluorescence was observed.Item Embargo 1-Borabenzonitrile ( B -cyanoboratabenzene)(Royal Society of Chemistry, 2011) Cade, Ian; Hill, AnthonyThe reaction of 1-chloro-2-(trimethylsilyl)-1-boracyclohexa-2,5-diene with [nBu4N]CN provides the 1-borabenzonitrile salt [nBu4N][C5H5BCN] which in turn reacts with [Ru4(μ-Cl)4(η-C5Me5)4] to afford the sandwich complex [Ru(η6- C5H5BCN)(η-C5Me5)]. TheItem Metadata only 1-Ethynyl-2-isopropoxy-3-methoxybenzene(Munksgaard International Publishers, 2003) Williams, Craig; Mander, Lewis; Bernhardt, PaulThe crystal structure of the title compound, C12H 14O2, has been determined at 150 K. Significant intermolecular non-conventional C-H⋯O interactions involving the terminal acetylinic H atom are observed, which result in a zigzag hydrogen-bonded chain inItem Restricted 1-supertransitive subfactors with index at most 6+1/5(Springer Verlag, 2014) Liu, Zhengwei; Morrison, Scott; Penneys, DavidWe classify irreducible II_1 subfactors A \subset B such that B \ominus A is reducible as an A-A bimodule, with index at most 6+1/5, leaving aside the composite subfactors at index exactly 6. Previous work has already achieved this up to index 3+\sqrt{5} \approx 5.23. We find there are exactly three such subfactors with index in (3+\sqrt{5}, 6+1/5], all with index 3+2\sqrt{2}. One of these comes from SO(3)_q at a root of unity, while the other two appear to be closely related, and are `braided up to a sign'.Item Embargo 1-Trimethylsilylethynyl-, 1-ethenyl- and 1-formyl-1- ethynylferrocenes: Syntheses and electrochemical properties(Elsevier, 2013) Grelaud, Guillaume; Argouarch, Gilles; Cifuentes, Marie; Paul, Frederic; Humphrey, MarkEfficient syntheses of 1′-trimethylsilylethynyl-, 1′-ethenyl-, and 1′-formyl-1-ethynylferrocenes are reported. The majority of these compounds exhibit chemically reversible ferrocene-based oxidation processes from cyclic voltammetry and thereby consItem Open Access The 1.06 frequency ratio in the cochlea: evidence and outlook for a natural musical semitone(PeerJ, 2017) Bell, Andrew; Jedrzejczak, W. WiktorA frequency ratio of about 1.06 often appears in cochlear mechanics, and the question naturally arises, why? The ratio is close to that of the semitone (1.059) in music, giving reason to think that this aspect of musical perception might have a cochlear basis. Here, data on synchronised spontaneous otoacoustic emissions is presented, and a clustering of ratios between 1.05 and 1.07 is found with a peak at 1.063 +/- 0.005. These findings reinforce what has been found from previous sources, which are reviewed and placed alongside the present work. The review establishes that a peak in the vicinity of 1.06 has often been found in human cochlear data. Several possible cochlear models for explaining the findings are described. Irrespective of which model is selected, the fact remains that the cochlea itself appears to be the origin of a ratio remarkably close to an equal-tempered musical semitone, and this close coincidence leads to the suggestion that the inner ear may play a role in constructing a natural theory of music. The outlook for such an enterprise is surveyed.Item Embargo 1.1-billion-year-old porphyrins establish a marine ecosystem dominated by bacterial primary producers(National Academy of Sciences, 2018) Gueneli, Nur; McKenna, A M; Ohkouchi, N; Boreham, Christopher; Beghin, Jérémie; Javaux, Emmanuelle J; Brocks, JochenThe average cell size of marine phytoplankton is critical for the flow of energy and nutrients from the base of the food web to higher trophic levels. Thus, the evolutionary succession of primary producers through Earth’s history is important for our understanding of the radiation of modern protists ∼800 million years ago and the emergence of eumetazoan animals ∼200 million years later. Currently, it is difficult to establish connections between primary production and the proliferation of large and complex organisms because the mid-Proterozoic (∼1,800–800 million years ago) rock record is nearly devoid of recognizable phytoplankton fossils. We report the discovery of intact porphyrins, the molecular fossils of chlorophylls, from 1,100-million-year-old marine black shales of the Taoudeni Basin (Mauritania), 600 million years older than previous findings. The porphyrin nitrogen isotopes (δ15Npor = 5.6–10.2) are heavier than in younger sedimentary sequences, and the isotopic offset between sedimentary bulk nitrogen and porphyrins (epor = −5.1 to −0.5) points to cyanobacteria as dominant primary producers. Based on fossil carotenoids, anoxygenic green (Chlorobiacea) and purple sulfur bacteria (Chromatiaceae) also contributed to photosynthate. The low epor values, in combination with a lack of diagnostic eukaryotic steranes in the time interval of 1,600–1,000 million years ago, demonstrate that algae played an insignificant role in mid-Proterozoic oceans. The paucity of algae and the small cell size of bacterial phytoplankton may have curtailed the flow of energy to higher trophic levels, potentially contributing to a diminished evolutionary pace toward complex eukaryotic ecosystems and large and active organisms.Item Embargo 1.6 MHz scanning rate direct absorption temperature measurements using a single vertical-cavity surface-emitting laser diode(Optical Society of America, 2018) Kaebe, Benjamin D; Robins, Nicholas; Boyson, Toby K.; Kleine, H.; O’Byrne, SeanThis paper presents 1.6 MHz scan rate, non-intrusive, time-resolved temperature measurements of a normal shock reflection from a plane end wall within a shock tube. A vertical-cavity surface-emitting laser (VCSEL) was used to conduct tunable diode laser absorption spectroscopy with water vapor as the probe species. The results are compared with analytical predictions. Temperatures measured with this technique agree within a single-scan standard deviation of ±33 K with calculated temperatures at a VCSEL modulation frequency of 800 kHz, which is sufficiently rapid enough to be used to investigate highly transient shock wave interaction processes.Item Embargo 1.60 Ga felsic volcanic blocks in the moraines of the Terre Adélie Craton, Antarctica: comparisons with the Gawler Range Volcanics, South Australia(Blackwell Publishing Ltd, 2002) Peucat, J-J; Capdevila, R; Fanning, Christopher; Menot, R P; Pecora, L; Testut, LRhyodacite and rhyolite blocks found in numerous moraines on the Terre Adélie Craton in Antarctica are samples of a high-temperature high-K calc-alkaline to alkali-calcic igneous suite emplaced at ca 1.60 Ga. They comprise lavas and pyroclastic rocks, in