https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52458 Wed 11 Oct 2023 15:01:14 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19734 P2₁∣n, and a further transition associated with antiferromagnetic ordering at ⁓8.5 K. The main structural changes, through the phase transition, are orientational ordering of the azetidium groups and associated changes in hydrogen bonding. In marked contrast to conventional improper ferroelastic oxide perovskites, the driving mechanism is associated with the X-point of the cubic Brillouin zone rather than being driven by R- and M-point octahedral tilting. The total ferroelastic shear strain of up to ⁓5% is substantially greater than found for typical oxide perovskites, and highlights the potential of the flexible framework to undergo large relaxations in response to local structural changes. Measurements of elastic and anelastic properties by resonant ultrasound spectroscopy show some of the characteristic features of ferroelastic materials. In particular, acoustic dissipation below the transition point can be understood in terms of mobility of twin walls under the influence of external stress with relaxation times on the order of ⁓10⁻⁷s. Elastic softening as the transition is approached from above is interpreted in terms of coupling between acoustic modes and dynamic local ordering of the azetidium groups. Subsequent stiffening with further temperature reduction is interpreted in terms of classical strain–order parameter coupling at an improper ferroelastic transition which is close to being tricritical. By way of contrast, there are no overt changes in elastic or anelastic properties near 9 K, implying that any coupling of the antiferromagnetic order parameter with strain is weak or negligible.]]> Sat 24 Mar 2018 07:53:46 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26919 Sat 24 Mar 2018 07:23:34 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52777 Mon 29 Jan 2024 18:24:35 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38173 2(NO₃)₂ (HPU-10) (H₂L = 2,6-bis-(5-pyridin-4-yl-1H-[1,2,4]triazol-3-yl)- pyridine), and demonstrate that this novel chemosensor has the property of ratiometric detection of Zn2+ and Cd2+. The detection limit of HPU-10 sensing Zn²⁺ and Cd²⁺ is 0.319 and 0.965 μM, respectively. The sensing mechanism can be explained by (i) the decomposition of HPU-10 and (ii) the recombination of Zn²⁺ or Cd²⁺ with ligand forming 2HL^--Zn²⁺ or 2HL^--Cd²⁺, respectively. Moreover, the fluorescent sensor HPU-10 can detect the nitroaromatic compound 2, 4-DNP via a fluorescence quenching mechanism. The detection limits obtained from linear regression curve plots of 2, 4-DNP is calculated to be 1.69 μM. In addition, the possible use of the probe coated paper for tracing the target analytes has also been presented.]]> Fri 06 Aug 2021 13:39:40 AEST ]]>