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An unexpected iron(Ⅱ)-promoted reaction of N-arylprop-2-yn-1-imines with water:Facile assembly of multi-substituted pyrroles

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Chinese Chemical Letters 2021年第1期32卷 37-39页

作者： Kaida Zhou Jiapian Huang Jie Wu Guanyinsheng Qiu School of Pharmaceutical and Materials Engineering&Institute for Advanced Studies Taizhou UniversityTaizhou 318000China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China College of Biological Chemical Science and EngineeringJiaxing UniversityJiaxing 314001China

Generation of multi-substituted pyrroles is accomplished through an unexpected iron(Ⅱ)-promoted reaction of N-arylprop-2-yn-1-imines with wate *** transformation proceeds smoothly with excellent chemoselectivityand regioselectivity.A stoichiometric amount of Fe(OTf)_(2) is necessary for the succes s ful conversion.A Lewis acid-promoted tandem reaction pathway is proposed.

关键词： Tandem reaction Iron(Ⅱ)triflate Prop-2-yn-1-imine Pyrrole Water

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Empowering Machines to Think Like Chemists: Unveiling Molecular Structure-Polarity Relationships with Hierarchical Symbolic Regression

arXiv

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arXiv 2024年

作者： Lou, Siyu Liu, Chengchun Chen, Yuntian Mo, Fanyang Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai200240 China Ningbo Institute of Digital Twin Eastern Institute of Technology Ningbo315200 China School of Materials Science and Engineering Peking University Beijing100871 China -Preferred Program Peking University Shenzhen Graduate School Shenzhen518500 China

Thin-layer chromatography (TLC) is a crucial technique in molecular polarity analysis. Despite its importance, the interpretability of predictive models for TLC, especially those driven by artificial intelligence, remains a challenge. Current approaches, utilizing either high-dimensional molecular fingerprints or domain-knowledge-driven feature engineering, often face a dilemma between expressiveness and interpretability. To bridge this gap, we introduce Unsupervised Hierarchical Symbolic Regression (UHiSR), combining hierarchical neural networks and symbolic regression. UHiSR automatically distills chemical-intuitive polarity indices, and discovers interpretable equations that link molecular structure to chromatographic behavior. Copyright © 2024, The Authors. All rights reserved.

关键词： Thin layer chromatography

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Two-dimensional material-assisted remote epitaxy and van der Waals epitaxy: a review

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National science Open 2023年第4期2卷 86-102页

作者： Zhetong Liu Bingyao Liu Zhaolong Chen Shenyuan Yang Zhiqiang Liu Tongbo Wei Peng Gao Zhongfan Liu Electron Microscopy Laboratory and International Center for Quantum MaterialsSchool of PhysicsPeking UniversityBeijing 100871China Beijing Graphene Institute(BGI) Beijing 100095China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China Center for Nanochemistry(CNC) Beijing Science and Engineering Center for NanocarbonsBeijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Institute for Functional Intelligent Materials National University of SingaporeSingapore 117575Singapore State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Research and Development Center for Semiconductor Lighting Technology Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Collaborative Innovation Center of Quantum Matter Beijing 100871China

Heteroepitaxy can reduce the cost and widen the application range of semiconductor film synthesis and device ***,the lattice and thermal expansion coefficient mismatches between epilayers and substrates limit the improvement of crystal quality and device ***-dimensional(2D)material-assisted heteroepitaxy offers an effective solution to these *** weak interaction at the interface between films and substrates facilitates the subsequent exfoliation and transfer of epilayer for the fabrication of flexible or high-power ***,we summarize the modes of 2D material-assisted epitaxy,which can be classified into remote epitaxy,pinhole epitaxy and van der Waals epitaxy based on the interfacial interaction between the epilayers and ***,we discuss in detail the improved crystal quality and functional applications,such as flexible devices,wavelength-modulated optoelectronic devices,and thermal management in high-power ***,we highlight the challenges and prospects of 2D material-assisted epitaxy,providing roadmaps for lateral research and semiconductor production.

关键词： graphene 2D materials heteroepitaxy remote epitaxy pinhole epitaxy van der Waals epitaxy

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Needle-induced-fracking in soft solids with crack blunting

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EXTREME MECHANICS LETTERS 2022年 52卷

作者： Song, Zhaoqiang Cai, Shengqiang Department of Mechanical and Aerospace Engineering University of California San Diego La Jolla CA 92093 USA Materials Science and Engineering Program University of California San Diego La Jolla CA 92093 USA

Fracking, also known as hydraulic fracture, has been intensively studied in hard and brittle materials such as shale rocks and ice. In contrast, little is known about fracking in soft solids, especially with significant crack blunting. Recently, it has been found that during the needle-induced-cavitation experiments on soft gels or elastomers, the materials can be ruptured by pressurized fluid. Due to the large elastofracture length, a short crack in a soft solid during the fracking often shows severely blunted tips, and therefore, the crack extension and large deformation in the material become nearly indistinguishable in the experiments. In this letter, we propose to adopt a simple model, considering both large deformation and crack blunting, to predict the change of the hydraulic pressure during the needle-induced-fracking in soft solids. We found that the theoretical predictions agree very well with experimental data reported in the literature. The studies presented in this letter may provide new insights into the understanding of the fracking in soft tissues and cells, and lead to a facile way to measure fracture energy of soft materials, which can be very challenging for conventional testing methods. (C) 2022 Elsevier Ltd. All rights reserved.

关键词： Hydraulic fracture Soft solid Needle-induced fracking Fracture toughness Cavitation-to-fracture

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In situ structural determination of 3d and 5d perovskite oxides under high pressure by synchrotron x-ray diffraction

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Physical Review B 2023年第13期108卷 134106-134106页

作者： Jie Chen Jiaming He Yanyao Zhang Stella Chariton Vitali Prakapenka Kazunari Yamaura Jung-Fu Lin J. B. Goodenough J.-S. Zhou Materials Science and Engineering Program Mechanical Engineering University of Texas at Austin Austin Texas 78712 USA Department of Earth and Planetary Sciences Jackson School of Geosciences The University of Texas at Austin Austin Texas 78712 USA Center for Advanced Radiation Sources The University of Chicago Illinois 60637 USA Research Center for Materials Nanoarchitectonics (MANA) National Institute for Materials Science 1-1 Namiki Tsukuba Ibaraki 305-0044 Japan Graduate School of Chemical Sciences and Engineering Hokkaido University North 10 West 8 Kita-ku Sapporo Hokkaido 060–0810 Japan

In contrast to the Mott transition found in RNiO3 (R= rare earths), the metal-insulator transition temperature in the perovskite NaOsO3 is not sensitive to pressure. The peculiarity may be correlated to how the crystal structure of NaOsO3 responds to high pressure, which has been rarely studied so far. The pressure-induced bond-length shrinking can increase the orbital overlap integral and therefore the electron bandwidth. However, in the orthorhombic perovskite structure, the pressure-induced bending in the bond angle Os-O-Os may compensate for the bandwidth broadening due to the bond-length shrinking in some circumstances. A recent structural study on polycrystalline NaOsO3 indicated that orthorhombic distortion is enlarged under high pressure. But, how the local structure changes under pressure remains unknown. Moreover, a highly unusual phase transition from the orthorhombic phase (Pbnm) to a polar phase (Pbn21) occurs at around 18 GPa [Sereika et al., npj Quantum Mater. 5, 66 (2020)]. Motivated by these concerns, we have done a more comprehensive structural study on NaOsO3 using single-crystal diffraction with synchrotron radiation at high pressures up to 41 GPa. Diffraction patterns over the entire pressure range can be refined well with the Pbnm structural model. Moreover, the refinement results reveal in detail how the local structures change under pressure corresponding to the enhanced orthorhombic distortion from the lattice parameters. We have carried out a systematic study for understanding the pressure effect on the orthorhombic perovskites in the context of the influences of the charge distributions in the ABO3 formula, i.e., A3+B3+O3, A2+B4+O3, and A1+B5+O3 and the B-site cations from the 3d to the 4d and 5d row of elements. To fulfill this purpose, we have revisited two families of 3d perovskites: RCrO3 and RFeO3.

关键词： Phase transitions Crystal structures X-ray diffraction

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Recent advancements and prospects in carbon-based nanomaterials derived from biomass for environmental remediation applications

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Chemosphere 2024年 357卷 141935页

作者： Vijeata, Anjali Chaudhary, Ganga Ram Chaudhary, Savita Ibrahim, Ahmed A. Umar, Ahmad Department of Chemistry and Centre of Advanced Studies in Chemistry Panjab University Chandigarh160014 India Najran University Najran11001 Saudi Arabia Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

The conversion of waste biomass into a value-added carbonaceous nanomaterial highlights the appealing power of biomass valorization. The advantages of using sustainable and cheap biomass precursors exhibit the tremendous opportunity for boosting energy production and their application in environmental remediation processes. This review emphasis the development and production of carbon-based nanomaterials derived from biomass, which possess favourable characteristics such as biocompatibility and photoluminescence. The advantages and limitations of various nanomaterials synthesised from different precursors were also discussed with insights into their physicochemical properties. The surface morphology of the porous nanomaterials is also explored along with their characteristic properties like regenerative nature, non-toxicity, ecofriendly nature, unique surface area, etc. The incorporation of various functional groups confers superiority of these materials, resulting in unique and advanced functional properties. Further, the use of these biomass derived nanomaterials was also explored in different applications like adsorption, photocatalysis and sensing of hazardous pollutants, etc. The challenges and outcomes obtained from different carbon-based nanomaterials are briefly outlined and discussed in this review. © 2024 Elsevier Ltd

关键词： Physicochemical properties

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Direct observation of structural phase transformations during continuous phosphorus deposition on Cu(111)

arXiv

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arXiv 2024年

作者： David, Jiří Jeřábek, František Procházka, Pavel Černý, Miroslav Ciobanu, Cristian V. Průša, Stanislav Šikola, Tomáš Kodambaka, Suneel Kolíbal, Miroslav Institute of Physical Engineering Brno University of Technology Technická 2 Brno616 69 Czech Republic CEITEC BUT. Brno University of Technology Purkyňova 123 Brno612 00 Czech Republic Department of Mechanical Engineering Materials Science Program Colorado School of Mines GoldenCO80401 United States Department of Materials Science and Engineering Virginia Polytechnic Institute State University BlacksburgVA24061 United States

Blue phosphorene - two-dimensional, hexagonal-structured, semiconducting phosphorus - has gained attention as it is considered easier to synthesize on metal surfaces than its allotrope, black phosphorene. Recent studies report different structures of phosphorene, for example, on Cu(111), but the underlying mechanisms of their formation are not known. Here, using a combination of in situ ultrahigh vacuum low-energy electron microscopy and in vacuo scanning tunneling microscopy, we determine the time-evolution of the surface structure and morphology during the deposition of phosphorus on single-crystalline Cu(111). We find that during early stages of deposition, phosphorus intermixes with Cu, resulting in copper phosphide structures. With increasing surface concentration of phosphorus, the phosphide phase disappears and a blue phosphorene layer forms, followed by self-assembly of highly ordered phosphorus clusters that eventually grow into multilayer islands. We attribute the unexpected transformation of stable phosphide to a phosphorene layer, and the previously unreported multilayer growth, to the presence of a large concentration of P2 dimers on the surface. Our results constitute direct evidence for a new growth mode leading to a phosphorene layer via an intermediary phase, which could underpin the growth of other 2D materials on strongly interacting substrates. © 2024, CC BY-SA.

关键词： Self assembly

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Tunable Multimodal Guided Surface Lattice Resonances in Index-Discontinuous Environments

arXiv

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arXiv 2024年

作者： Huang, Suichu Yao, Kan Huang, Wentao Zhao, Xuezheng Zheng, Yuebing Pan, Yunlu Key Laboratory of Micro-Systems and Micro-Structures Manufacturing Ministry of Education School of Mechatronics Engineering Harbin Institute of Technology Harbin150001 China Walker Department of Mechanical Engineering Material Science and Engineering Program Texas Materials Institute The University of Texas at Austin AustinTX78712 United States

Surface lattice resonances (SLRs) in metasurfaces are promising in applications of sub-wavelength devices, owning properties such as high quality (high-Q) factors, large local field enhancement and extensive long-range interaction. The tunable peak position and multimodal resonances of SLRs further enhance their appeal for flexible and multi-wavelength light-matter interactions. Despite these advantages, the realization of tunable multimodal SLRs often requires reconfiguring the lattices, leading to limited tunability. Furthermore, current high-Q SLR implementations necessitate a homogeneous dielectric environment, restricting potential applications such as biosensors that are typically operated in an aqueous or air cladding on a substrate. Here we present guided-SLRs (gSLRs), which are easily accessible in index-discontinuous environments while retaining the multimodal property and straightforward tunability of mode number, resonance wavelengths and mode coupling strengths. The gSLRs are achieved by coupling the scattered light from metasurface units into a slab waveguide, creating a light propagating channel in the lattice plane within an index-asymmetric environment. Tailoring the radiation pattern of individual units with guided transverse electric (TE) and transverse magnetic (TM) modes, multimodal resonances in both orthogonal and parallel coupling directions are accomplished. The mode number and resonance wavelengths can be easily controlled by adjusting the waveguide configuration, while the mode coupling strength is tuned by the vertical position of lattices in the slab. Further shift of the multimodal gSLRs from visible to near-infrared is achieved by introducing a gold backplane. The easy-to-access, flexibly tunable and multimodal gSLRs in inhomogeneous media offer a promising solution to advancing the realization of ultrathin and ultracompact nano-optical and optoelectronic devices. Copyright © 2024, The Authors. All rights reserved.

关键词： Waveguides

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Corrosion-Resistant and Ultrafine-Grained Boron-Containing Stainless Steel Produced by Laser Powder Bed Fusion

SSRN

引用

SSRN 2024年

作者： Freitas, Brenda Juliet Martins Koga, Guilherme Yuuki de Traglia Amancio-Filho, Sergio Bolfarini, Claudemiro Federal University of São Carlos Graduate Program in Materials Science and Engineering São Carlos13.565-905 Brazil Graz University of Technology Institute of Materials Science Joining and Forming Graz8010 Austria Federal University of São Carlos Department of Materials Engineering São Carlos13.565-905 Brazil Rod. Washington Luis SP São CarlosCEP 13565-905 Brazil

Ultrafine-grained stainless steel armored with borides was produced by laser powder bed fusion (L-PBF). The in-situ formed composite was characterized by refined grains of high-alloyed ferritic stainless steel matrix with hard and rigid nanoborides along the grain boundaries. Besides being hard and wear resistant, the resulted material was unsensitized and resistant against pitting corrosion, with corrosion resistance comparable to a SAF 2205 duplex stainless steel. Besides unveiling the microstructural and electrochemical nexus, this work opens positive perspectives to surpass the corrosion-wear resistance trade-off upon the in-situ formation of stainless steel matrix reinforced by hard Cr-containing nanoborides using additive manufacturing technologies. © 2024, The Authors. All rights reserved.

关键词： Steel corrosion

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Polarization and orientation dependent optical properties in Czochralski-grown transition metal doped β-Ga2O3 14

Polarization and orientation dependent optical properties in...

引用

Oxide-based materials and Devices XIV 2023

作者： Dutton, Benjamin L. Remple, Cassandra Jesenovec, Jani Ghandiparsi, Soroush Gottlieb, Miranda S. Varley, Joel B. Voss, Lars F. McCluskey, Matthew D. McCloy, John S. Institute of Materials Research Washington State University PullmanWA99164-2711 United States Materials Science & Engineering Program Washington State University PullmanWA99164-2711 United States Dept. of Physics and Astronomy Washington State University PullmanWA99164-2814 United States Lawrence Livermore National Laboratory LivermoreCA94551-0808 United States

ISBN: (纸本)9781510659490

Properties of monoclinic β-Ga2O3 are strongly dependent upon orientation. In the case of optical properties, polarization can reveal differences in optical bandgap and absorptions related to transition metal ions. This phenomenon is known as pleochroism and has been extensively studied in minerology. β-Ga2O3 bulk single crystals doped with Zn, Mn, Cr, or Cu were grown by the Czochralski and vertical gradient freeze methods. Ultraviolet-visible-near infrared spectroscopy and photoluminescence (PL) revealed polarization- and orientation-dependent optical absorptions in β-Ga2O3. Crystals were annealed in reducing and oxidizing environments in an attempt to alter the intensities of absorptions characteristic to the different transition metal oxidation states in a given ligand field. Visible pleochroism was strongest in (001) oriented Mn-doped samples as shown by polarized optical microscopy. All samples were electrically insulating, indicative of acceptor doping, aside from Cr-doped samples where Cr acts as a deep donor. © 2023 SPIE.

关键词： Polarization

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