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Co-aromatization of methane and hexane over Pt encapsulated in ZSM-5 zeolite and the electronic effect of K promoters

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Science China Chemistry 2024年第3期67卷 1017-1027页

作者： Bei Liu fan Wang Xiaomeng Dou Pengfei Li Hongwei Xiang Yong Yang Peng He State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China Department of Chemistry Tsinghua UniversityBeijing 100084China National Energy r&D Center for Coal to Liquid fuels Synfuels China Technology Co.Ltd.Beijing 101407China University of Chinese Academy of Sciences Beijing 101408China Leibniz-institut für Katalyse e.V.an der Universitat rostock Rostock 18059Germany

The co-aromatization of methane with higher hydrocarbons represents a promising route to valorize methane, an abundant but underexploited carbon resource. In this study, we elucidate a novel approach to enhance the catalytic co-aromatization of hexane and methane by confining Pt within zeolite catalysts and modulating its electron density. Our findings show that encapsulating Pt within MfI structure is pivotal for activating the feedstock and fostering the formation of aromatic products. Interaction between K atoms and the silanol nest forms siloxy groups which are critical for the stabilization of Pt species. Tuning the K content in PtSn@MfI catalysts adeptly alters the electronic configuration of Pt clusters. This modification is corroborated by infrared and X-ray photoelectron spectroscopy analysis, and density functional theory calculations. remarkably, the catalyst with 0.8 wt% K exhibits an optimal Pt electron density, driving its superior efficacy in the co-aromatization reaction, converting 0.78 mol of methane for each mole of hexane processed. By employing ~(13)C isotopic labeling and solid-state NMr studies, we demonstrate the participation of methane in the adsorbed species inside the zeolite channel and its incorporation to the benzyl site of the substitute group and phenyl rings in aromatic compounds, underscoring the importance of Pt encapsulation.

关键词： Pt encapsulation MfI zeolite methane activation co-aromatization ^(13)C solid-state NMr

A reevaluation of the correlation between the synthesis parameters and structure and properties of nitrogen-doped carbon nanotubes

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Journal of Energy Chemistry 2015年第4期24卷 407-415页

作者： Kunpeng Xie fengkai Yang Petra Ebbinghaus Andreas Erbe Martin Muhler Wei Xia Laboratory of Industrial Chemistry Ruhr-University Bochum max-planck-institut für Eisenforschung Gmb H

Nitrogen-doped carbon nanotubes（NCNTs） were synthesized by chemical vapor deposition using cobaltbased oxides as catalyst and ethylenediamine（EDA） as carbon/nitrogen precursor. The influence of growth time,EDA concentration and growth temperature on the morphology,yield,composition,graphitization and oxidation resistance of the NCNTs was systematically investigated by using raman spectroscopy,temperature-programmed oxidation and other techniques. The NCNT growth from ethylenediamine with a high N/C ratio involves several processes including mainly（1） catalytic growth of NCNTs,（2） homogeneous gas-phase decomposition of EDA,（3） non-catalytic deposition of pyrolytic carbon/nitrogen species and（4）surface etching of amorphous carbon or carbon at defect sites through gasification. At a later growth stage the etching process appears to be dominating,leading to the thinning of nanotubes and the decrease of ***,the surface etching through carbon gasification strongly influences the structure and degree of graphitization of NCNTs.

关键词： Carbon nanotubes Nitrogen-doping Catalytic chemical vapor deposition Ethlyenediamine Carbon gasification

Multi-segment linear gradient optimization strategy based on resolution map in HPLC

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Science China Chemistry 2006年第4期49卷 315-325页

作者： Andreas Seidel-Morgenstern max-planck-institut fr Dynamik Komplexer Technischer Systeme Magdeburg 39106 Germany

Based on the mechanism of chromatographic retention (the relationship between the retention of solute and the mobile phase conditions) and method of resolution map, several methods of optimizing multi-segment linear gradient elution conditions were proposed according to the different separation requirements of various samples. These methods were verified using literature data. Moreover, the advantages and disadvantages of these methods were compared. It was proved that the third method is a fast optimization method which is capable of separating all the components with relatively high resolution.

关键词： optimization, multi-segment, linear gradient, resolution map, liquid chromatography.

A machine learning approach to model solute grain boundary segregation

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npj Computational Materials 2018年第1期4卷 130-137页

作者： Liam Huber raheleh Hadian Blazej Grabowski Jörg Neugebauer max-planck-institut für Eisenforschung GmbH D-40237 DüsseldorfGermany

Even minute amounts of one solute atom per one million bulk atoms may give rise to qualitative changes in the mechanical response and fracture resistance of modern structural *** changes are commonly related to enrichment by several orders of magnitude of the solutes at structural defects in the host *** underlying concept—segregation—is thus fundamental in materials *** include it in modern strategies of materials design,accurate and realistic computational modelling tools are ***,the enormous number of defect configurations as well as sites solutes can occupy requires models which rely on severe *** the present study we combine a high-throughput study containing more than 1 million data points with machine learning to derive a computationally highly efficient framework which opens the opportunity to model this important mechanism on a routine basis.

关键词： grain solute boundary

Characteristics of the SOL ion-to-electron temperature ratio on the J-TEXT tokamak with different plasma configurations

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Plasma Science and Technology 2024年第2期26卷 13-21页

作者：李存凯梁云峰江中和周松华建坤阳杰杨庆虎 Alexander KNIEPS Philipp DrEWS 徐鑫毛飞越谢伟杨雨桐郭金龙李杨波任正康陈志鹏王能超 the J-TEXT Team International Joint research Laboratory of Magnetic Confinement fusion and Plasma Physics State Key Laboratory of Advanced Electromagnetic Engineering and TechnologySchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People's Republic of China forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung—PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)Julich 52425Germany 不详

Accurate measurement of the average plasma parameters in the edge region,including the temperature and density of electrons and ions,is critical for understanding the characteristics of the scrape-off layer(SOL) and divertor plasma transport in magnetically confined fusion *** the J-TEXT tokamak,a multi-channel retarding field analyzer(rfA) probe has been developed to study average plasma parameters in the edge region under various poloidal divertor and island divertor *** edge radial profile of the ion-to-electron temperature ratio,τ_(i/e),has been determined,which gradually decreases as the SOL ion self-collisionality,v_(SOL)*,*** is broadly consistent with what has been observed previously from various tokamak ***,the comparison of experimental results under different configurations shows that in the poloidal divertor configuration,even under the same v_(SOL)*,τ_(i/e) in the SOL region becomes smaller as the distance from the X-point to the target plate *** the island divertor configuration,τ_(i/e) near the O-point is higher than that near the X-point at the same v_(SOL)*,and both are higher than those in the limiter *** results suggest that the magnetic configuration plays a critical role in the energy distributions between electrons and ions at the plasma boundary.

关键词： ion temperature island divertor poloidal divertor retarding field analyzer(rfA)probe

Three thousand years in Tibet

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National Science review 2020年第1期7卷 129-130页

作者： Bettina Harr Trevor Price max-planck-institut für Evolutionsbiologie Department of Ecology and Evolution University of Chicago

Humans have come to inhabit nearly every terrestrial environment. Their commensals have followed them and have consequently become some of the most abundant and widespread species on Earth, in the process becoming exposed to a variety of abiotic and biotic stressors. for example, the house sparrow was introduced from the UK to North America in the

关键词： Three thousand years in Tibet

Characteristics of elution profile in radial chromatography under linear conditions

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Science China Chemistry 2005年第4期48卷 352-360页

作者： Andreas Seidel-Morgenstern max-planck-institut für Dynamik Komplexer Technischer Systeme 39106MagdeburgGermany

Based on the mass balance equations of solute transfer in the radial chroma-tographic column,the theoretical expression to describe the column efficiency and shape of elu-tion profile is obtained under linear isotherm ***,the tendency for the variation of column efficiency and symmetry of peak profile is systematically *** results showed that in radial chromatography the relationship between the column efficiency and volumetric flow rate is similar with that relationship in axial chromatography;relatively high column efficiency still can be obtained under high flow rate in radial *** the increase of retention factor of solutes and injection time,the column efficiency decreases *** effect of column diameter and column length on the column efficiency interfere with each *** is more advantageous to increase the column efficiency by applying columns with larger column diameter and shorter column *** to the discussion of the effect of diffusion on the column efficiency,radial chromatography is proved to be suitable for the separation of samples with relatively high diffusion coefficient,which predicts its obvious advantage in the preparative separation of samples such as proteins and DNA.

关键词： radial chromatography, column efficiency, elution profile, symmetry.

New insights into AGNs with low-mass black holes and high accretion rates:the case of narrow-line Seyfert 1 galaxies

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中国科学：物理学、力学、天文学英文版 2010年第S1期53卷 216-219页

作者： KOMOSSA S max-planck-institut für extraterrestrische Physik

Narrow-line Seyfert 1(NLS1) galaxies are believed to harbor low-mass black holes accreting at high rates,and they are therefore important targets when studying the nature of black hole growth,galaxy evolution,and accretion *** have rigorously studied the physical properties of a sample of NLS1 *** briefly review previous findings and present new results,including:(1) The locus of NLS1 galaxies on the MBH-σ plane,which we find to follow the relation of non-active galaxies after removing objects obviously dominated by outflows.(2) The presence of "blue outliers" which hint at extreme outflows as they would be predicted from merger models.(3) More subtle evidence for winds and outflows across the whole NLS1 population.(4) New correlations and trends which link black hole mass,Eddington ratio and physical parameters of the emission-line region.A new element is added to the eigenvector 1 space based on a principal component analysis,which aims at identifying the main drivers of AGN correlation properties.

关键词： active galactic nuclei emission lines density outflow

Hetero-integrated high-peak-optical-power laser source (940 nm) for time-of-flight sensors

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Chinese Optics Letters 2024年第7期22卷 81-85页

作者： Sergey Olegovich Slipchenko Aleksandr Aleksandrovich Podoskin Ilia Vasil'evich Shushkanov Marina Gennad'evna rastegaeva Artem Eduardovich rizaev Matvey Igorevich Kondratov Artem Evgen'evich Grishin Nikita Aleksandrovich Pikhtin Timur Anatol'evich Bagaev maxim Anatol'evich Ladugin Aleksandr Anatol'evich Marmalyuk Vladimir Aleksandrovich Simakov Ioffe institut Russian Academy of SciencesSt.Petersburg 194021Russia Open Joint-Stock Company M.f.Stel’makh Polyus research institute Moscow 117342Russia rUDN University Moscow 117198Russia

The generation of high-power laser pulses using a compact hetero-integrated assembly based on a semiconductor laser with a dual-element composite 2μm×100μm aperture and a compact heterothyristor switch is *** achieved peak optical power was 33 W with a pulse duration of 3 ns at a thyristor operating voltage of 55 *** leading edge of the laser pulse turn-on was 50 ps to a power level of 24.7 W,and the turn-on delay between the elements of the composite aperture was 160 ps.

关键词： hetero-integrated assembly semiconductor lasers thyristor switches LIDAr gain-switching mode laser heterostructure