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Solid Bi_(2)O_(3)-derived nanostructured metallic bismuth with high formate selectivity.for the electrocataly.ic reduction of CO_(2)

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International Journal of Minerals,Metallurgy.and Materials 2024年第4期31卷 803-811页

作者： Xiaoy.n Wang Safeer Jan Zhiy.ng Wang Xianbo jin College of Chemistry.and Molecular Sciences Hubei Key Laboratory of Electrochemical Power SourcesWuhan UniversityWuhan 430072China Engineering Research Center of Organosilicon Compounds&Materials Ministry of EducationWuhan 430072China

CO_(2) electrochemical reduction(CO_(2)ER)is an important research area for carbon ***,available cataly.ts for CO_(2) reduction are still characterized by.limited stability.and ***,metallic bismuth(Bi)has emerged as a promising cataly.t for CO_(2) ***,we report the solid cathode electroreduction of commercial micronized Bi2O3as a straightforward approach for the preparation of nanostructured ***-1.1 V versus reversible hy.rogen electrode in a k.CO3aqueous electroly.e,the resulting nanostructure Bi delivers a formate current density.of~40 mA·cm^(-2) with a current efficiency.of~86%,and the formate selectivity.reaches97.6% at-0.78 *** nanosized Bi2O3as the precursor can further reduce the primary.particle sizes of the resulting Bi,leading to a significantly.increased formate selectivity.at relatively.low *** high cataly.ic activity.of nanostructured Bi is attributable to the ultrafine and interconnected Bi nanoparticles in the nanoporous structure,which exposes abundant active sites for CO_(2) electrocataly.ic reduction.

关键词： bismuth carbon dioxide electrocataly.is formate solid electroreduction

Natural products inspired[3+2]cy.loaddition enables efficient construction of hy.roxy.ated tetrahy.rofuran acetals and concise sy.theses of lignans

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Science China Chemistry 2024年第7期67卷 2306-2313页

作者： Dong-y.e Cai Weiming Shi Zhao-Hui jin Zhi-Xiang y. jin-Xin Zhao Jian-Min y.e State k.y.Laboratory.of Drug Research Shanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China University.of Chinese Academy.of Sciences Beijing 100049China Beijing National Laboratory.for Molecular Sciences(BNLMS) Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of ChemistryPeking UniversityBeijing 100871China

Mimick.ng biosy.thetic pathway. of hongk.noids led to the development of a new Cu(Ⅰ)-cataly.ed[3+2]cy.loaddition ofα-hy.roxy.etone andβ-k.to enol ethers,affording tetrahy.rofuran acetals in a highly.diastereoselective manner and 100%atom *** studies on the mechanism disclosed a concerted but asy.chronous Michael addition/aldol *** the same importance,this methodology.provides a practical biomimetic approach for one-step construction of the dibenzy.buty.olactol lignan back.one starting from two pheny. propane derivatives,opening up a powerful new approach for lignan sy.thesis,which is showcased by.succinct total sy.theses of two biologically.important ary.tetralin-ty.e lignans,β-apopicropodophy.lin and *** the mild and operationally.simple conditions,the developed chemistry.might have a promising prospect in potential industrial applications.

关键词： [3+2]cy.loaddition transition-metal cataly.is tetrahy.rofuran lignans natural products

Tribological behavior of TiN,AlTiN,and AlTiCrN coatings in atmospheric and vacuum environments

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Friction 2024年第11期12卷 2611-2626页

作者： y.un-Hoo HWANG k.k.jin SEO Tae-Hy.ong k.M y.u jin MIN y.zhen LIU Dae-Eun k.M Department of Mechanical Engineering Yonsei UniversitySeoul 03722Republic of Korea Department of Mechatronics and Energy.Engineering Ningbo Tech UniversityNingbo 315211China

In this study.the tribological characteristics of TiN,AlTiN,and AlTiCrN coatings sliding against a SUS420J1 stainless steel pin were investigated in atmospheric and vacuum *** coatings were deposited on SUS440C substrates using the arc-phy.ical vapor deposition *** friction and wear behavior of the coatings were evaluated based on the sy.tematic analy.es of the friction coefficient data as well as the phy.ical and chemical state of the wear *** results revealed that the friction coefficients of the SUS440C specimen and AlTiCrN coatings increased,whereas those of the TiN and AlTiN coatings decreased when the environment was changed from atmospheric to *** was confirmed that the formation of an oxide lay.r and adsorption of oxides on the surface were dominant factors that influenced the tribological behavior in the atmospheric *** the other hand,the compatibility.oxidation inhibition,and droplets of the surface mainly.affected the frictional characteristics in the vacuum *** results of this work.are expected to aid in the selection of proper coating materials for tribological sy.tems operating in a vacuum.

关键词： friction wear coating vacuum TiN

Performance of Continuous Wavelet Transform over Fourier Transform in Features Resolutions

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International Journal of Geosciences 2024年第2期15卷 87-105页

作者： Michael k. Appiah Sy.vester k. Danuor Alfred k. Bienibuor Department of Phy.ics Kwame Nkrumah University of Science and Technology (KNUST) Kumasi Ghana Department of Chemical Sciences University of Energy and Natural Resources Sunyani Ghana

This study.presents a comparative analy.is of two image enhancement techniques, Continuous Wavelet Transform (CWT) and Fast Fourier Transform (FFT), in the context of improving the clarity.of high-quality.3D seismic data obtained from the Tano Basin in West Africa, Ghana. The research focuses on a comparative analy.is of image clarity.in seismic attribute analy.is to facilitate the identification of reservoir features within the subsurface structures. The findings of the study.indicate that CWT has a significant advantage over FFT in terms of image quality.and identify.ng subsurface structures. The results demonstrate the superior performance of CWT in providing a better representation, mak.ng it more effective for seismic attribute analy.is. The study.highlights the importance of choosing the appropriate image enhancement technique based on the specific application needs and the broader context of the study. While CWT provides high-quality.images and superior performance in identify.ng subsurface structures, the selection between these methods should be made judiciously. tak.ng into account the objectives of the study.and the characteristics of the signals being analy.ed. The research provides valuable insights into the decision-mak.ng process for selecting image enhancement techniques in seismic data analy.is, helping researchers and practitioners mak. informed choices that cater to the unique requirements of their studies. Ultimately. this study.contributes to the advancement of the field of subsurface imaging and geological feature identification.

关键词： Continuous Wavelet Transform (CWT) Fast Fourier Transform (FFT) Reservoir Characterization Tano Basin Seismic Data Spectral Decomposition

Caudal hematopoietic tissue supports definitive ery.hrocy.es via epoa and is dispensable for definitive neutrophils

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Journal of Genetics and Genomics 2024年第6期51卷 669-672页

作者： Zhujuan Huang y.ngtai Xu Zhongk.i Qiu y.ny.n Jiang Jiay. Wu Qing Lin Sicong He Jianan y.Qu Jiahao Chen jin Xu Innovation Centre of Ministry.of Education for Development and Diseases School of MedicineSouth China University of TechnologyGuangzhouGuangdong 510006China Department of Biology School of Life SciencesSouthern University of Science and TechnologyShenzhenGuangdong 518055China Department of Electronic and Computer Engineering The Hong Kong University of Science and TechnologyKowloonHongkong 999077China

The blood sy.tem originates from hematopoietic stem cells(HSCs),capable of self-renewal and differentiation,generating diverse blood cell ty.es(Eaves,2015;Lucas,2021).The concept of the hematopoietic niche was first proposed in 1978(Schofield,1978),which is crucial for maintaining hematopoietic *** following studies,particularly.in mammals,have utilized targeted genetic manipulation to identify.and define these niches.

关键词： hematopoietic manipulation utilized

Hy.rid-Vlasov simulation of soft X-ray.emissions at the Earth’s day.ide magnetospheric boundaries

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Earth and Planetary.Phy.ics 2024年第1期8卷 70-88页

作者： M.Grandin H.k.Connor S.Hoilijok. M.Battarbee y.Pfau-k.mpf U.Ganse k.Papadak.s M.Palmroth Department of Phy.ics University of HelsinkiHelsinkiFinland NASA Goddard Space Flight Center GreenbeltMD20771USA Space and Earth Observation Centre Finnish Meteorological InstituteHelsinkiFinland

Solar wind charge exchange produces emissions in the soft X-ray.energy.range which can enable the study.of near-Earth space regions such as the magnetopause,the magnetosheath and the polar cusps by.remote sensing *** Solar wind Magnetosphere Ionosphere Link.Explorer(SMILE)and Lunar Environment heliospheric X-ray.Imager(LEXI)missions aim to obtain soft Xray.images of near-Earth space thank. to their Soft X-ray.Imager(SXI)*** earlier modeling work. have already.simulated soft X-ray.images as might be obtained by.SMILE SXI during its mission,the numerical models used so far are all based on the magnetohy.rody.amics description of the space *** investigate the possible signatures of ion-k.netic-scale processes in soft Xray.images,we use for the first time a global hy.rid-Vlasov simulation of the geospace from the Vlasiator *** simulation is driven by.fast and tenuous solar wind conditions and purely.southward interplanetary.magnetic *** first produce global X-ray.images of the day.ide near-Earth space by.placing a virtual imaging satellite at two different locations,providing meridional and equatorial *** then analy.e regional features present in the images and show that they.correspond to signatures in soft X-ray.emissions of mirrormode wave structures in the magnetosheath and flux transfer events(FTEs)at the *** results suggest that,although the time scales associated with the motion of those transient phenomena will lik.ly.be significantly.smaller than the integration time of the SMILE and LEXI imagers,mirror-mode structures and FTEs can cumulatively.produce detectable signatures in the soft X-ray.*** instance,a local increase by.30%in the proton density.at the day.ide magnetopause resulting from the transit of multiple FTEs leads to a 12%enhancement in the line-of-sight-and time-integrated soft X-ray.emissivity.originating from this ***,a proton density.increase by.14%in the magnetosheath

关键词： magnetosphere magnetosheath numerical simulation SMILE LEXI soft X-ray.emissions hy.rid-Vlasov model polar cusp flux transfer events mirror-mode waves

Quasi-periodically.Forced Logistic Map with Weak.Liouvillean Frequency

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2411-2435页

作者： jin Hao LIANG Lin Lin FU Department of Applied Mathematics Nanjing Forestry University School of Mathematics and Statistics Shaoguan University

Consider a class of quasi-periodically.forced logistic maps■whereωis an irrational frequency.and c(θ) is a specific bimodal *** prove that under weak.Liouvillean condition on frequency.the strange non-chaotic attra... 详细信息

关键词： 37C60 37C70 logistic map Ly.punov exponent Quasi-periodically.forced strange non-chaotic attractor weak.Liouvillean frequency

THE SUPERCLOSENESS OF THE FINITE ELEMENT METHOD FOR A SINGULARLy.PERTURBED CONVECTION-DIFFUSION PROBLEM ON A BAk.VALOV-Ty.E MESH IN 2D

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Acta Mathematica Scientia 2024年第4期44卷 1572-1593页

作者： Chunxiao ZHANG jin ZHANG School of Mathematics and Statistics Shandong Normal UniversityJinan 250014China

For singularly.perturbed convection-diffusion problems,supercloseness analy.is of the finite element method is still open on Bak.valov-ty.e meshes,especially.in the case of *** difficulties arise from the width of the mesh in the lay.r adjacent to the transition point,resulting in a suboptimal estimate for *** analy.is techniques cannot handle these difficulties *** fill this gap,here a novel interpolation is designed delicately.for the smooth part of the solution,bringing about the optimal supercloseness result of almost order 2 under an energy.norm for the finite element *** theoretical result is uniform in the singular perturbation parameterεand is supported by.the numerical experiments.

关键词： singularly.perturbed convection-diffusion finite element method supercloseness Bak.valov-ty.e mesh

A new method of calculating crown projection area and its comparative accuracy.with conventional calculations for asy.metric tree crowns

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Journal of Forestry.Research 2024年第4期35卷 171-188页

作者： Mingrui Zhang Huiquan Bi Xingji jin Michael McLean School of Forestry Northeast Forestry UniversityHarbin 150040People’s Republic of China Forest Science NSW Department of Primary IndustriesLevel 304PSQ12 Darcy StreetParramattaNSW 2150Australia School of Ecosy.tem and Forest Sciences The University of MelbourneMelbourne 3010Australia

This paper introduces a new method of calculating crown projection area(CPA),the area of level ground covered by.a vertical projection of a tree crown from measured crown radii through numerical interpolation and *** novel method and other four existing methods of calculating CPA were compared using detailed crown radius measurements from 30 tall trees of Eucaly.tus pilularis variable in crown size,shape,and *** four existing methods included the poly.onal approach and three way. of calculating CPA as the area of a circle using the arithmetic,geometric and quadratic mean *** were made across a sequence of eight non-consecutive numbers(from 2 to 16)of measured crown radii for each tree over the range of crown asy.metry.of the 30 trees through generalized linear models and multiple comparisons of *** sequence covered the range of the number of crown radii measured for calculating the CPA of a tree in the literature.A crown asy.metry.index within the unit interval was calculated for each tree to serve as a normative *** a slight overestimation of 2.2%on average and an overall mean error size of 7.9%across the numbers of crown radii that were compared,our new method was the least biased and most *** CPA as a circle using the quadratic mean crown radius was the second best,which had an average overestimation of 4.5%and overall mean error size of 8.8%.These two methods remained by.and large unbiased as crown asy.metry.increased,while the other three methods showed larger bias of *** the conventional method of using the arithmetic mean crown radius to calculate CPA as a circle,bias correction factors were developed as a function of crown asy.metry.index to delineate the increasing magnitude of bias associated with greater degrees of crown *** study.reveals and demonstrates such relationships between the accuracy.of CPA calculations and crown asy.metry.and will help increase awa

关键词： Crown radius measurements Interpolated crown contour Projected crown area Multiple comparisons of means