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Combining ATR far- and mid-infrared spectroscopy to distinguish native Australian plant exudates for cultural heritage analysis
(Elsevier, 2025-04) Mann, AK; Appadoo, DRT; Lenehan, CE; Popelka-Filcoff, RS
Native Australian plant exudates are an important material for a variety of cultural uses including hafting materials and pigment binders. Spectroscopic analysis of exudates informs on their composition, properties, use and conservation status. However, native Australian exudates are not as well characterized as European species, although there are often chemical parallels between the two. While mid-IR has been demonstrated as an effective and standard method to distinguish some key exudate species, the fingerprint-region characterisation can become challenging for a particular group of exudates due to spectral similarities or overlaps, and therefore discrimination is not easily achievable. Therefore, the complementary data on molecular interactions observed in the far-IR region can provide additional means to characterize and discriminate between genera. In this study, samples from European artist materials and native Australian exudates were studied by both laboratory-based mid-IR and synchrotron based far-IR. Results from this work include establishing a novel non-destructive far-IR method for plant exudates such as resins, gums and kinos on the molecular level, as well as multivariate statistical analysis to differentiate at both the genera and species level. These outcomes identify an innovative approach to understanding these complex molecular chemistries of plant exudates as well as a method to characterize resins, kinos and gums in important archaeological and cultural heritage materials in Australia and worldwide. © 2025 The Authors. Published by Elsevier Ltd.
Temporal variability of atmospheric radon‐222 concentration at Gosan Station, Jeju Island, Korea, during 2009–2013
(Wiley, 2015-01-23) Song, JM; Kim, WH; Kang, CH; Lee, HY; Lee, CK; Chambers, SD; Williams, AG
Atmospheric radon‐222 (radon) measurements were made from 2009 to 2013 at the Gosan station of Jeju Island, one of the cleanest regions in Korea, in order to characterize the temporal variability (on diurnal, seasonal, and annual scales) and analyze the influence of changing air mass transport pathways on observed radon concentrations. The mean hourly radon concentration over the whole period was 2441 ± 1037 mBq/m3. The seasonal cycle of radon at the Gosan station was characterized by a fall maximum and summer minimum, consistent with a reduction in nonfrozen terrestrial fetch from fall to summer. In order, the seasonal mean radon concentrations were 2962 mBq/m3 (fall) >2907 mBq/m3 (winter) >2219 mBq/m3 (spring) >1756 mBq/m3 (summer). Based on a 5‐year composite, the maximum mean monthly radon concentration in October (3100 mBq/m3) was more than twice the July minimum (1471 mBq/m3). Diurnal composite radon concentrations for the whole period increased throughout the night to a maximum of 2788 mBq/m3 at around 7 a.m., and then gradually decreased to a minimum of 2050 mBq/m3 at around 3 p.m. The winter diurnal cycle had a small amplitude due to the low variability in atmospheric mixing depth associated with recent air mass fetch over the Yellow Sea. The diurnal cycle in summer, however, exhibited a relatively large amplitude due to changes in atmospheric mixing depth associated with recent fetch over Jeju Island. Back trajectory analysis showed that high radon events were typically associated with long‐term air mass fetch over continental Asia. Specifically, the average radon concentration of air masses originating from China was about 2.4 times higher than that of air masses originating from the North Pacific Ocean. © 1999-2025 John Wiley & Sons, Inc or related companies.
Liquid-phase sintering of lead halide perovskites and metal-organic framework glasses
(American Association for the Advancement of Science, 2021-10-28) Hou, JW; Chen, P; Shukla, A; Krajnc, A; Wang, TiS; Li, XM; Doasa, R; Tizei, LHG; Chan, B; Johnstone, D; Lin, R; Schülli, TU; Martens, I; Appadoo, DRT; Ari, MS; Wang, ZL; Wei, T; Lo, SC; Lu, MY; Li, SC; Namdas, EB; Mali, Gregor; Cheetham, AK; Collins, SM; Chen, V; Wang, LZ; Bennett, TD
Lead halide perovskite (LHP) semiconductors show exceptional optoelectronic properties. Barriers for their applications, however, lie in their polymorphism, instability to polar solvents, phase segregation, and susceptibility to the leaching of lead ions. We report a family of scalable composites fabricated through liquid-phase sintering of LHPs and metal-organic framework glasses. The glass acts as a matrix for LHPs, effectively stabilizing nonequilibrium perovskite phases through interfacial interactions. These interactions also passivate LHP surface defects and impart bright, narrow-band photoluminescence with a wide gamut for creating white light-emitting diodes (LEDs). The processable composites show high stability against immersion in water and organic solvents as well as exposure to heat, light, air, and ambient humidity. These properties, together with their lead self-sequestration capability, can enable breakthrough applications for LHPs. © 2025 American Association for the Advancement of Science.
Selective in situ phase segregation enabling efficient and stable protonic ceramic fuel cell cathode performance
(Wiley, 2025-06-09) Feng, DH; Peterson, VK; Zhu, Tianjiu; Lin, R; D'Angelo, AM; Appadoo, DRT; Tian, XH; Du, XY; Zhu, ZH; Li, MR
Efficient and reliable protonic ceramic fuel cells (PCFCs) necessitate the development of active and durable cathode materials to accelerate the sluggish oxygen reduction reaction (ORR). The most promising PCFC cathode candidates are perovskite‐type structured oxides with mixed oxygen ion, proton, and hole conductivity. However, mixed conductivity often requires materials with alkaline earth elements and the inclusion of these elements in the cathode structure leads to severe degradation in the presence of even small trace amounts of CO2 in air. Herein, a new approach is presented to address this challenge by inducing selective in situ phase segregation to engineer the cathode surface and bulk separately. This selective phase segregation is achieved via targeted control of the size mismatch of cations in the perovskite‐type structure, enhancing charge transfer in the bulk while improving CO2 resistance at the surface. By co‐incorporating smaller Li+ and larger K+ into the model BaCo0.4Fe0.4Zr0.1Y0.1O3−δ cathode material, it is shown that Li+ segregates to the surface, protecting it from CO2 poisoning, while K+ remains in the bulk and accelerates proton transport. Consequently, this in situ restructured cathode can boost the PCFC power output by 30% and improve its CO2 tolerance fivefold in the presence of CO2 at 600 °C. © 2025 The Author(s). Small published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution-Non Commercial Licence
High-resolution Fourier transform infrared spectrum of the ν 6 band of formamide-d1 (DCONH2)
(Elsevier, 2019-09) Wu, QY; Tan, TL; Ng, LL; Appadoo, DRT
The high-resolution rovibrational spectrum of the ν6 band of formamide-d1 (DCONH2) was recorded using the Fourier transform infrared (FTIR) spectrometer at the Australian Synchrotron with an unapodized resolution of 0.00142 cm−1 in the mid-infrared region of 910–990 cm−1 region. From the rovibrational analysis of this A-type band, the v6 = 1 state rovibrational constants up to one sextic term were derived for the first time from a total of 1450 infrared transitions. These transitions were fitted using the Watson's A-reduced Hamiltonian in the Ir representation with a root-mean-square (rms) deviation of 0.00078 cm−1. The center of the ν6 band of DCONH2 was accurately determined to be 954.857070(41) cm−1. This v6 = 1 state was found to be perturbed by the nearby (v10=1,v12 = 1) state, just around 16 cm−1 higher. Two c-Coriolis parameters were obtained from the perturbation analysis of the interaction between the rotational energy levels of the v6 = 1 and (v10=1,v12 = 1) states. Additionally, the center of the ν10+ν12 band was found at 970.671(41) cm−1 and rotational constant C was fitted accurately. Ground state rotational constants and centrifugal distortion constants up to two sextic terms were obtained by fitting of 1432 ground state combination differences (GSCDs) derived from the infrared (IR) transitions of both the ν6 band of the present work and ν12 band of previous work of DCONH2, together with 6 previously reported microwave frequencies. The root-mean-square (rms) deviation value of this fit was 0.000183 cm−1. The ground state constants in this study provide a better representation for the DCONH2 isotopologue as the values were derived from a larger pool of GSCDs. In addition, ground state rovibrational constants up to five quartic terms and rotational constants of the v6 = 1 state were computed from theoretical anharmonic calculations at two different levels of theory, B3LYP and MP2 with the cc-pVTZ basis set, for comparison with the experimental results. © 2019 Elsevier Inc.

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