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1. Better Durability with Less Iridium: Control of the Crystal Phase of Iridium–Ruthenium–Manganese Electrocatalysts for Oxygen Evolution Reaction Performance

   https://doi.org/10.1021/acs.chemmater.5c01947  

   Song, Anran; Chen, Yan-Ru; Ghosh, Bidipta; Yang, Hong (November 2025, Chemistry of Materials)

   This paper presents a study of designing phase-specific and -mixed Ir−Ru−Mn trimetallic electrocatalysts with enhanced performance. By changing the content of Ru, the alloy electrocatalyst evolved from a face-centered tetragonal (fct) phase to a mixture of fct and hexagonal close-packed (hcp) phases and finally to the hcp phase. Among these trimetallic systems, the hcp-phase Ir0.23Ru0.20Mn0.57 electrocatalyst (Ru/Ir = 0.47:0.53) delivered the best performance toward the oxygen evolution reaction (OER), achieving an overpotential of 226 mV at 10 mA cm−2 and a Tafel slope of ∼46.8 mV dec−1. Interestingly, this low-Ir hcp-phase catalyst maintained stable operation for >57 h at a current density of 100 mA cm−2 in 0.1 M HClO4, whereas the Ir-rich fct-phase counterpart (Ir0.35Ru0.07Mn0.58) degraded within 22 h under identical conditions. Potentiodynamic polarization curve study indicated that oxidative dissolution is the dominant degradation pathway, and the structural characterizations indicated that the hcp-phase alloy remained intact, while rutile-type IrRuMnOx oxide was formed for the fct-phase alloy electrocatalyst. These results underscore the effect of the crystal phase on OER durability of the electrocatalyst and point to a design strategy for improving the durability of OER electrocatalysts without increasing the Ir content. 

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2. GridNet: Fast date-driven EM-induced IR drop prediction and localized fixing for on-chip power grid networks

   Zhou, H; Jin, W.; Tan, S. X.-D. (October 2020, Proc. IEEE/ACM International Conf. on Computer-Aided Design (ICCAD’20),)

   Electromigration (EM) is a major failure effect for on-chip power grid networks of deep submicron VLSI circuits. EM degradation of metal grid lines can lead to excessive voltage drops (IR drops) before the target lifetime. In this paper, we propose a fast data-driven EM-induced IR drop analysis framework for power grid networks, named {\it GridNet}, based on the conditional generative adversarial networks (CGAN). It aims to accelerate the incremental full-chip EM-induced IR drop analysis, as well as IR drop violation fixing during the power grid design and optimization. More importantly, {\it GridNet} can naturally leverage the differentiable feature of deep neural networks (DNN) to {\it obtain the sensitivity information of node voltage with respect to the wire resistance (or width) with marginal cost}. {\it GridNet} treats continuous time and the given electrical features as input conditions, and the EM-induced time-varying voltage of power grid networks as the conditional outputs, which are represented as data series images. We show that {\it GridNet} is able to learn the temporal dynamics of the aging process in continuous time domain. Besides, we can take advantage of the sensitivity information provided by {\it GridNet} to perform efficient localized IR drop violation fixing in the late stage design and optimization. Numerical results on 36000 synthesized power grid network samples demonstrate that the new method can lead to $$10^5\times$$ speedup over the recently proposed full-chip coupled EM and IR drop analysis tool. We further show that localized IR drop violation fix for the same set of power grid networks can be performed remarkably efficiently using the cheap sensitivity computation from {\it GridNet}. 

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3. Testosterone Treatment Mimics Seasonal Downregulation of Dopamine Innervation in the Auditory System of Female Midshipman Fish

   https://doi.org/10.1093/icb/icab070  

   Perelmuter, Jonathan T; Hom, Kelsey N; Mohr, Robert A; Demis, Lina; Kim, Spencer; Chernenko, Alena; Timothy, Miky; Middleton, Mollie A; Sisneros, Joseph A; Forlano, Paul M (May 2021, Integrative and Comparative Biology)

   Abstract In seasonally breeding vertebrates, hormones coordinate changes in nervous system structure and function to facilitate reproductive readiness and success. Steroid hormones often exert their effects indirectly via regulation of neuromodulators, which in turn can coordinate the modulation of sensory input with appropriate motor output. Female plainfin midshipman fish (Porichthys notatus) undergo increased peripheral auditory sensitivity in time for the summer breeding season, improving their ability to detect mates, which is regulated by steroid hormones. Reproductive females also show differences in catecholaminergic innervation of auditory circuitry compared with winter, non-reproductive females as measured by tyrosine hydroxylase (TH), the rate-limiting enzyme in catecholaminergic synthesis. Importantly, catecholaminergic input to the inner ear from a dopaminergic-specific forebrain nucleus is decreased in the summer and dopamine inhibits the sensitivity of the inner ear, suggesting that gonadal steroids may alter auditory sensitivity by regulating dopamine innervation. In this study, we gonadectomized non-reproductive females, implanted them with estradiol (E2) or testosterone (T), and measured TH immunoreactive (TH-ir) fibers in auditory nuclei where catecholaminergic innervation was previously shown to be seasonally plastic. We found that treatment with T, but not E2, reduced TH-ir innervation in the auditory hindbrain. T-treatment also reduced TH-ir fibers in the forebrain dopaminergic cell group that projects to the inner ear, and likely to the auditory hindbrain. Higher T plasma in the treatment group was correlated with reduced-ir TH terminals in the inner ear. These T-treatment induced changes in TH-ir fibers mimic the seasonal downregulation of dopamine in the midshipman inner ear and provide evidence that steroid hormone regulation of peripheral auditory sensitivity is mediated, in part, by dopamine. 

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4. Intermolecular coupling and fluxional behavior of hydrogen in phase IV

   https://doi.org/10.1073/pnas.1916385116  

   Goncharov, Alexander F.; Chuvashova, Irina; Ji, Cheng; Mao, Ho-kwang (December 2019, Proceedings of the National Academy of Sciences)

   We performed Raman and infrared (IR) spectroscopy measurements of hydrogen at 295 K up to 280 GPa at an IR synchrotron facility of the Shanghai Synchrotron Radiation Facility (SSRF). To reach the highest pressure, hydrogen was loaded into toroidal diamond anvils with 30-μm central culet. The intermolecular coupling has been determined by concomitant measurements of the IR and Raman vibron modes. In phase IV, we find that the intermolecular coupling is much stronger in the graphenelike layer (G layer) of elongated molecules compared to the Br 2 -like layer (B layer) of shortened molecules and it increases with pressure much faster in the G layer compared to the B layer. These heterogeneous lattice dynamical properties are unique features of highly fluxional hydrogen phase IV. 

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5. Closed-loop atomic force microscopy-infrared spectroscopic imaging for nanoscale molecular characterization

   https://doi.org/10.1038/s41467-020-17043-5  

   Kenkel, Seth; Mittal, Shachi; Bhargava, Rohit (June 2020, Nature Communications)

   Abstract Atomic force microscopy-infrared (AFM-IR) spectroscopic imaging offers non-perturbative, molecular contrast for nanoscale characterization. The need to mitigate measurement artifacts and enhance sensitivity, however, requires narrowly-defined and strict sample preparation protocols. This limits reliable and facile characterization; for example, when using common substrates such as Silicon or glass. Here, we demonstrate a closed-loop (CL) piezo controller design for responsivity-corrected AFM-IR imaging. Instead of the usual mode of recording cantilever deflection driven by sample expansion, the principle of our approach is to maintain a zero amplitude harmonic cantilever deflection by CL control of a subsample piezo. We show that the piezo voltage used to maintain a null deflection provides a reliable measure of the local IR absorption with significantly reduced noise. A complete analytical description of the CL operation and characterization of the controller for achieving robust performance are presented. Accurate measurement of IR absorption of nanothin PMMA films on glass and Silicon validates the robust capability of CL AFM-IR in routine mapping of nanoscale molecular information. 

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