Effect of the heating rate on the thermal explosion behavior and oxidation resistance of 3D-structure porous NiAl intermetallic

Porous NiAl intermetallic compounds demonstrate great potential in various applications by their high porosity and excellent oxidation resistance. However, to obtain a controllable NiAl intermetallic structure by tuning different process parameters remains unclear. In this work, porous NiAl intermetallic compounds were fabricated by economic and energy-saving thermal explosion (TE) reaction. The relationship between microstructure and process parameters was revealed using three-dimensional X-ray microscopy (3D-XRM) with high resolution and non-destructive characteristics. The geometrical features and quantitative statistics of the porous NiAl obtained at different heating rates (2, 10, 20 \ub0C min−1) were compared. The result of the closed porosity calculation showed that a lower heating rate (2 \ub0C min−1) promoted the Kirkendall reaction between Ni and Al, resulting in a high closed porosity (5.25%). However, at a higher heating rate (20 \ub0C min−1), a homogeneous NiAl phase was observed using the threshold segmentation method, indicating uniform and complete TE reaction can be achieved at a high heating rate. The result of the 3D fluid simulation showed that the sample heated at 10 \ub0C min−1 had the highest permeability (2434.6 md). In this study, we systematically investigated the relationship between the heating rates and properties of the porous NiAl intermetallic, including the phase composition, porosity, exothermic mechanism, oxidation resistance, and compression resistance. Our work provides constructive directions for designing and tailoring the performance of porous NiAl intermetallic compounds

SurrealDriver: Designing Generative Driver Agent Simulation Framework in Urban Contexts based on Large Language Model

Simulation plays a critical role in the research and development of autonomous driving and intelligent transportation systems. However, the current simulation platforms exhibit limitations in the realism and diversity of agent behaviors, which impede the transfer of simulation outcomes to the real world. In this paper, we propose a generative driver agent simulation framework based on large language models (LLMs), capable of perceiving complex traffic scenarios and providing realistic driving maneuvers. Notably, we conducted interviews with 24 drivers and used their detailed descriptions of driving behavior as chain-of-thought prompts to develop a `coach agent' module, which can evaluate and assist driver agents in accumulating driving experience and developing human-like driving styles. Through practical simulation experiments and user experiments, we validate the feasibility of this framework in generating reliable driver agents and analyze the roles of each module. The results show that the framework with full architect decreased the collision rate by 81.04% and increased the human-likeness by 50%. Our research proposes the first urban context driver agent simulation framework based on LLMs and provides valuable insights into the future of agent simulation for complex tasks.Comment: 12 pages, 8 figure

Visible-light-induced trifluoromethylation of allylic alcohols

An organic photoredox-catalyzed dehydroxylative trifluoromethylation of allylic alcohols was developed in an environmentally benign manner. In this reaction, the readily available CF3SO2Na was selected as the trifluoromethylation reagent. The in situ generated byproduct SO2 was reutilized to activate C-OH bond, which enabled this dehydroxylative trifluoromethylation to be performed conveniently. A variety of multifunctionalized CF3-allylic compounds were obtained in high yields and excellent stereoselectivity.We gratefully acknowledge financial support from the National Natural Science Foundation of China (21702108), the Natural Science Foundation of Jiangsu Province, China (BK20160977), and the Six Talent Peaks Project in Jiangsu Province (YY-033)

Phosphine-Catalyzed [4 + 2] Annulation of γ‑Substituent Allenoates: Facile Access to Functionalized Spirocyclic Skeletons

The first phosphine-catalyzed [4 + 2] annulation of γ-substituted allenoates with 2-arylidene-1<i>H</i>-indene-1,3(2<i>H</i>)-diones is disclosed. In the reaction, the γ-substituted allenoate serves as a new type of 1,4-dipolar synthon; this broadens the application of γ-substituted allenoates. This method also offers a powerful approach to the construction of highly substituted spiro[4.5]dec-6-ene skeletons in excellent yields, and with complete regioselectivity and high diastereoselectivity

Zinc Amide Catalyzed Regioselective Allenylation and Propargylation of Ketones with Allenyl Boronate

Zinc amide catalyzed, regioselective allenylation and propargylation of ketones with allenyl boronate is reported. Tertiary allenyl and homopropargyl alcohols were obtained, respectively, in high selectivities, from the same starting materials, simply by changing the reaction conditions. The substrate scope was wide. Mechanistic studies suggest that the reactions are controlled under kinetic and thermodynamic conditions

Organophotoredox-catalyzed intermolecular formal Grob fragmentation of cyclic alcohols with activated allylic acetates

We have developed an efficient method that employs organophotoredox-catalyzed relay Grob fragmentation to facilitate the smooth ring-opening allylation of cyclic alcohols in an environmentally friendly manner. This protocol directly incorporates a wide spectrum of cyclic alcohols and activated allylic acetates into the cross-coupling reaction, eliminating the need for metal catalysts. The process yields a variety of distally unsaturated ketones with good to excellent outcomes and stereoselectivity, while acetic acid is the sole byproduct.We gratefully acknowledge financial support from the National Natural Science Foundation of China (21702108), the Natural Science Foundation of Jiangsu Province, China (BK20211257), and the Six Talent Peaks Project in Jiangsu Province (YY-033)

Porous NiFe-LDH grown on graphene oxide towards highly efficient OER electrocatalysis

Porous few-layer NiFe-layered double hydroxide (PLDH)/graphene oxide (GO) composite electrocatalysts (PLDH/GO) were successfully synthesized through a formamide-assisted coprecipitation method. The ratio of PLDH to GO was optimized, and the structure, morphology and electrochemical properties of samples were systematically investigated. The results show that PLDH with obvious porous and few-layer features uniformly grows on GO, and part of PLDH layer is perpendicular to GO layer and part parallel to GO layer. PLDH/0.1GO sample exhibits the best oxygen evolution reaction performance with the overpotential of 236 mV at 10 mA cm, and the Tafel slope of 52 mV dec, which is far superior to commercial IrO and pure LDH in the same test condition.This work is supported by the National Natural Science Foundation of China (51874305, 52020105011), the Open Sharing Fund for the Large-scale Instruments and Equipments of China University of Mining and Technology (DYGX-2020-013)

Direct substitution of secondary and tertiary alcohols to generate sulfones under catalyst- and additive-free conditions

An environmentally benign protocol that affords propargylic sulfones containing highly congested carbon centers from easily accessible alcohols and sulfinic acids with water as the only byproduct is reported. The reaction proceeded via an in situ dehydrative cross-coupling process by taking advantage of the synergetic actions of multiple hydrogen bonds rather than relying on an external catalyst and/or additives to achieve high product distribution

Barium-catalyzed C–OH/P–H dehydrative cross-coupling for C–P bond construction

A barium-catalyzed C–OH/P–H dehydrative cross-coupling protocol for the construction of C–P bonds was developed. This reaction was performed in an environmentally benign manner with water as the only by-product. A variety of allylic phosphorus compounds can be isolated in good to excellent yields

Water-promoted C-S bond formation reactions

Allylic sulfones, owning to their widespread distributions in biologically active molecules, received increasing attention in the past few years. However, the synthetic method under mild conditions is still a challenging task. In this paper, we report a sulfinic acids ligation with allylic alcohols via metal-free dehydrative cross-coupling. Both aliphatic and aromatic sulfinic acids react with various allylic alcohols to deliver the desired allylic sulfones in high yields with excellent selectivity. This carbon–sulfur bond formation reaction is highly efficient and practical since it works under metal-free, neutral, aqueous media and at room temperature in which the products even can be obtained by simple filtration without the need for organic extraction or column chromatography. Water is found to be essential for the success of this carbon–sulfur bond formation reaction. DFT calculations imply that water acts as promoter in this transformation via intermolecular hydrogen bonds.Published versio