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1. Model Counting Meets F ₀ Estimation

   https://doi.org/10.1145/3603496  

   Pavan, A.; Vinodchandran, N. V.; Bhattacharyya, Arnab; Meel, Kuldeep S. (September 2023, ACM Transactions on Database Systems)

   Constraint satisfaction problems (CSPs) and data stream models are two powerful abstractions to capture a wide variety of problems arising in different domains of computer science. Developments in the two communities have mostly occurred independently and with little interaction between them. In this work, we seek to investigate whether bridging the seeming communication gap between the two communities may pave the way to richer fundamental insights. To this end, we focus on two foundational problems: model counting for CSP’s and computation of zeroth frequency moments (F₀) for data streams. Our investigations lead us to observe a striking similarity in the core techniques employed in the algorithmic frameworks that have evolved separately for model counting andF₀computation. We design a recipe for translating algorithms developed forF₀estimation to model counting, resulting in new algorithms for model counting. We also provide a recipe for transforming sampling algorithm over streams to constraint sampling algorithms. We then observe that algorithms in the context of distributed streaming can be transformed into distributed algorithms for model counting. We next turn our attention to viewing streaming from the lens of counting and show that framingF₀estimation as a special case of #DNF counting allows us to obtain a general recipe for a rich class of streaming problems, which had been subjected to case-specific analysis in prior works. In particular, our view yields an algorithm for multidimensional range efficientF₀estimation with a simpler analysis. 

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2. FedRolex: Model-Heterogeneous Federated Learning with Rolling Sub-Model Extraction

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3. A first-principles study of multilayer Ti ₃ C ₂ T _x MXene model

   https://doi.org/10.1039/D4NR02319F  

   Chu, Yi Zhi; Lau, Kah Chun (January 2024, Nanoscale)

   We proposed a more realistic albeit slightly complicated multilayer Ti3C2Tx model and performed a comprehensive theoretical study of its structural and electronic properties. In this work, we constructed various multilayer Ti3C2Tx structures considering different concentrations of hydrofluoric acid (HF; 5, 10, and 48 wt%) as the etchant. The validity of our ternary mixed O/OH/F-terminated Ti3C2Tx multilayer models is confirmed by the consistency of the calculated d-spacing (9.60 ± 0.07 Å), simulated X-ray diffraction (XRD) spectra and the predicted adhesion energy (0.77 ± 0.15 J m−2) with the reported experimental measurements. The uniform terminated and mixed terminated multilayer Ti3C2Tx exhibit metallic characteristics, similar to those of monolayer Ti3C2Tx. We found a stronger interaction between the interlayers with OH-rich ternary mixed terminated Ti3C2Tx surfaces, due to the formation of hydrogen bonds between the hydroxyl groups and adjacent layers of F/O terminal groups as supported by the crystal orbital Hamilton population (COHP) calculation. From this finding, we propose that multilayer Ti3C2Tx etched with a strong HF acid could be easily exfoliated into monolayer sheets due to smaller adhesion energy. Based on this work, we believe that the current findings will offer a fundamental understanding and a useful baseline multilayer model for the future investigation of the hydrogen and ion storage and diffusion properties in the MXene multilayer application. 

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4. Diradicals as Topological Charge Carriers in Metal–Organic Toy Model Pt ₃ (HIB) ₂

   https://doi.org/10.1021/jacs.4c09993  

   Goesten, Maarten G; Schoop, Leslie M (October 2024, Journal of the American Chemical Society)
5. Bimetallic iron–tin catalyst for N ₂ to NH ₃ and a silyldiazenido model intermediate

   https://doi.org/10.1039/D0CC04563B  

   Dorantes, Michael J.; Moore, James T.; Bill, Eckhard; Mienert, Bernd; Lu, Connie C. (January 2020, Chemical Communications)

   A tin-supported iron catalyst produces 5.9 turnovers of NH 3 from N 2 , using [Ph 2 NH 2 ]OTf as the acid and CoCp 2 * as the reductant. Two redox states of the Fe(N 2 ) adduct and an Fe silyldiazenido complex were characterized using X-ray crystallography along with NMR and Mössbauer spectroscopies. Density functional theory calculations reveal that the charge on the Sn center correlates strongly with both the polarization of the N 2 moiety and the charge on the distal N atom. 

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