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Greatly enhanced corrosion/wear resistances of epoxy coating for Mg alloy through a synergistic effect between functionalized graphene and insulated blocking layer

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Journal of Magnesium and Alloys 2024年第1期12卷 332-344页

作者： Z.y.Xue X.J.li J.H.Chu M.M.li d.n.Zou L.B.Tong School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China State Key Laboratory of Advanced design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China

The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various *** conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient *** the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly *** outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)*** FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier *** Ce film connects the outer layer with the substrate,showing the transition *** corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling *** synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.

关键词： Mg alloy Functionalized graphene Epoxy coating Corrosion/wear resistance Blocking layer

Chebyshev polynomial-based Ritz method for thermal buckling and free vibration behaviors of metal foam beams

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 891-910页

作者： n.d.nGUyEn T.n.nGUyEn Faculty of Civil Engineering Ho Chi Minh City University of Technology and EducationHo Chi Minh City 71309Viet Nam Faculty of Engineering and Technology Kien Giang UniversityChau Thanh 92000Viet Nam

This study presents the Chebyshev polynomials-based Ritz method to examine the thermal buckling and free vibration characteristics of metal foam *** analyses include three models for porosity distribution and two scenarios for thermal *** material properties are assessed under two conditions,i.e.,temperature dependence and temperature *** theoretical framework for the beams is based on the higher-order shear deformation theory,which incorporates shear deformations with higher-order *** governing equations are established from the Lagrange equations,and the beam displacement fields are approximated by the Chebyshev *** simulations are performed to evaluate the effects of thermal load,slenderness,boundary condition(BC),and porosity distribution on the buckling and vibration behaviors of metal foam *** findings highlight the significant influence of temperature-dependent(Td)material properties on metal foam beams'buckling and vibration responses.

关键词： Ritz method Chebyshev function buckling vibration metal foam beam higher-order beam theory(HOBT)

Influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 563-580页

作者： n.HUMnEKAR d.SRInIVASACHARyA department of Mathematics National Institute of TechnologyWarangal 506004TelanganaIndia

The influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel is *** darcyBrinkman model is used to characterize the fluid flow dynamics in porous *** analytical solutions are obtained for the unidirectional and completely developed *** on a normal mode analysis,the generalized eigenvalue problem under a perturbed state is *** eigenvalue problem is then solved by the spectral ***,the critical Rayleigh number with the corresponding wavenumber is evaluated at the assigned values of the other flow-governing *** results show that increasing the darcy number,the Lewis number,the dufour parameter,or the Soret parameter increases the stability of the system,whereas increasing the inclination angle of the channel destabilizes the ***,the flow is the most unstable when the channel is vertically oriented.

关键词： nanofluid inclined channel variable viscosity linear stability double dif-fusion porous medium

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On B(5,20) 2-Groups

ALGEBRA COLLOQUIUM 2024年第3期31卷 429-440页

作者： Alhassan, E. A. Tan, y. L. li, y. Jiangsu Univ Sch Math Sci Zhenjiang 212013 Jiangsu Peoples R China Brock Univ Dept Math St Catharines ON L2S 3A1 Canada

A finite group G is said to be a B( n, k) group if for any n-element subset { a(1) , & mldr; , a(n) } of G, | { a(i) a(j )| 1 <= i, j <= n } | <= k . It is of interest to characterize the structure of B( n, k) groups ... 详细信息

A finite group G is said to be a B( n, k) group if for any n-element subset { a(1) , & mldr; , a(n) } of G, | { a(i) a(j )| 1 n } | nterest to characterize the structure of B( n, k) groups for n( n+1 ) /2 n(2) - 1 . The B( 5, k) groups for 15 n investigated by several authors. In this paper, we give a complete characterization of B( 5, 20) 2-groups by showing there are five classes of such groups which are nontrivial and nonabelian.

关键词： B(n, k) groups small squaring property central extension GAP

distinct Electrical and Mechanical Responses of a Cu-10Fe Composite Prepared by Hot-Pressed Sintering and Post Treatment

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 255-265页

作者： X.y.yue S.y.Peng X.Zhang C.n.He y.Z.Tian Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China School of Materials Science and Engineering and Tianjin Key Laboratory of Composite and Functional Materials Tianjin UniversityTianjin300350China Research Centre for Metallic Wires Northeastern UniversityShenyang110819China

A Cu-10wt%Fe composite was prepared through hot-pressed sintering,and the material was subsequently solution *** hot-pressed sintered and solution treated materials were rolled and *** precipitation behavior and performance changes were systematically studied by using scanning electron microscopy and transmission electron *** contrast to the hot-pressed sintered specimen,the solution treatment significantly affects the thermal stability and properties of the Cu-10wt%Fe *** Cu-10wt%Fe composite was prepared after solid solution,cold rolling and aging at 773 K for 1 h,and it obtained excellent tensile strength of 494 MPa,uniform elongation of 16.3%,electrical conductivity of 51.1%IACS and softening temperature of 838 *** for the distinct difference in thermal stability and properties between hot-pressed sintered and solution treated specimens were *** findings provide a theoretical basis for designing high-performance Cu-based in-situ composites by post treatment.

关键词： Cu-Fe composite Hot-pressed sintering Thermal stability Strength Electrical conductivity

Polio eradication surveillance in Sri Lanka,2019-2023

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Asian Pacific Journal of Tropical Medicine 2024年第6期17卷 268-272页

作者： M.A.y.Fernando n.S.Madarasinghe C.Rangana n.Weerasinghe d.C.U.d.Weligamage J.I.Abeynayake department of Medical Microbiology and Immunology Faculty of MedicineUniversity of ColomboSri Lanka department of Virology Medical Research InstituteColombo 08Sri Lanka Medical Research Institute Colombo 08Sri Lanka

Objective:To evaluate the polio laboratory surveillance carried out from January,2019 to May,2023 by the Polio Regional Reference Laboratory,Sri ***:This retrospective study analyzed all stool samples received under the acute flaccid paralysis(AFP)and immunodeficient vaccine-derived poliovirus(VdPV)surveillance at Polio Regional Reference Laboratory,Sri Lanka from January,2019 to May,*** results of the testing methodologies were extracted from the laboratory data system,i.e.,poliovirus virus isolation,intra-typic differentiation/VdPV real time reverse transcriptase polymerase chain reaction(ITd/VdPV rRTPCR)and sequencing,along with the data on timing of reporting results,stool adequacy and *** was analyzed using descriptive ***:A total of 2141 stool samples from 1644 cases were received for AFP surveillance from Sri Lanka(93.61%),Maldives(1.52%),and immunodeficient VdPV(4.86%)*** polioviruses(19/1644,1.15%)and non-polio enteroviruses(73/1644,4.44%)were isolated,while Sabin-like 3 virus was detected in majority(12/19,63.15%)among the poliovirus *** polioviruses or circulating VdPVs were not detected among the *** all years of the study,the non-polio AFP detection rate was>1/100000 in children aged less than 15 years,whereas stool adequacy rate was>80%.All results were reported within 14 days of receipt,ensuring timely reporting as per global ***:The Polio Regional Reference Laboratory,Sri Lanka plays a vital role in maintaining the polio-free status in the country through its robust laboratory surveillance,while adhering to the surveillance ***-detection of wild polioviruses and circulating VdPV during the study period reinforces the polio-free status in the country.

关键词： Poliovirus Polio laboratory surveillance Regional reference laboratory Polio eradication

Inclusion of CoTiO_(3) to ameliorate the re/dehydrogenation properties of the Mg–na–Al system

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Journal of Magnesium and Alloys 2024年第3期12卷 1215-1226页

作者： n.A.Ali n.y.yusnizam n.A.Sazelee Sami-ullah Rather Haizhen liu M.Ismail Energy Storage Research Group Faculty of Ocean Engineering TechnologyUniversiti Malaysia Terengganu21030 Kuala NerusTerengganuMalaysia department of Chemical and Materials Engineering King Abdulaziz UniversityP.O.Box80204Jeddah 21589Saudi Arabia Guangxi novel Battery Materials Research Center of Engineering Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China State Key Laboratory of Featured Metal Materials and life-Cycle Safety for Composite Structures Nanning 530004China

For the first time,the MgH_(2)–naAlH_(4)(ratio 4:1)destabilized system with CoTiO_(3) addition has been *** CoTiO_(3)-doped MgH_(2)–naAlH_(4) sample begins to dehydrogenate at 130℃,which is declined by 40℃ compared to the undoped MgH_(2)–naAlH_(4).Moreover,the de/rehydrogenation kinetics characteristics of the CoTiO_(3)-doped MgH_(2)–naAlH_(4) were greatly *** the inclusion of CoTiO_(3),the MgH_(2)–naAlH_(4) composite absorbed 5.2 wt.%H_(2),higher than undoped MgH_(2)–naAlH_(4).In the context of dehydrogenation,the CoTiO_(3)-doped MgH_(2)–naAlH_(4) sample desorbed 2.6 wt.%H_(2),almost doubled compared to the amount of hydrogen desorbed from the undoped MgH_(2)–naAlH_(4) *** activation energy obtained by the Kissinger analysis for MgH_(2) decomposition was significantly lower by 35.9 kJ/mol than the undoped MgH_(2)–naAlH_(4) *** reaction mechanism demonstrated that new phases of MgCo and AlTi_(3) were generated in situ during the heating process and are likely to play a substantial catalytic function and be useful in ameliorating the de/rehydrogenation properties of the destabilized MgH_(2)–naAlH_(4) system with the inclusion of CoTiO_(3).

关键词： destabilize system Magnesium hydride Sodium alanate Hydrogen storage Additive.

Evidence for particle acceleration approaching PeV energies in the W51 complex

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Science Bulletin 2024年第18期69卷 2833-2841页

作者： Cao, Zhen Aharonian, F. Axikegu Bai, y.X. Bao, y.W. Bastieri, d. Bi, X.J. Bi, y.J. Bian, W. Bukevich, A.V. Cao, Q. Cao, W.y. Cao, Zhe Chang, J. Chang, J.F. Chen, A.M. Chen, E.S. Chen, H.X. Chen, liang Chen, lin Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, y. Cheng, n. Cheng, y.d. Cui, M.y. Cui, S.W. Cui, X.H. Cui, y.d. dai, B.Z. dai, H.L. dai, Z.G. danzengluobu dong, X.Q. duan, K.K. Fan, J.H. Fan, y.Z. Fang, J. Fang, J.H. Fang, K. Feng, C.F. Feng, H. Feng, L. Feng, S.H. Feng, X.T. Feng, y. Feng, y.L. Gabici, S. Gao, B. Gao, C.d. Gao, Q. Gao, W. Gao, W.K. Ge, M.M. Geng, L.S. Giacinti, G. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, X.L. Guo, y.Q. Guo, y.y. Han, y.A. Hasan, M. He, H.H. He, H.n. He, J.y. He, y. Hor, y.K. Hou, B.W. Hou, C. Hou, X. Hu, H.B. Hu, Q. Hu, S.C. Huang, d.H. Huang, T.Q. Huang, W.J. Huang, X.T. Huang, X.y. Huang, y. Ji, X.L. Jia, H.y. Jia, K. Jiang, K. Jiang, X.W. Jiang, Z.J. Jin, M. Kang, M.M. Karpikov, I. Kuleshov, d. Kurinov, K. li, B.B. li, C.M. li, Cheng li, Cong li, d. li, F. li, H.B. li, H.C. li, Jian li, Jie li, K. li, S.d. li, W.L. li, X.R. li, Xin li, y.Z. li, Zhe li, Zhuo liang, E.W. liang, y.F. lin, S.J. liu, B. liu, C. liu, d. liu, d.B. liu, H. liu, H.d. liu, J. liu, J.L. liu, M.y. liu, R.y. liu, S.M. liu, W. liu, y. liu, y.n. Luo, Q. Luo, y. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Min, Z. Mitthumsiri, W. Mu, H.J. nan, y.C. neronov, A. Ou, L.J. Pattarakijwanich, P. Pei, Z.y. Qi, J.C. Qi, M.y. Qiao, B.Q. Qin, J.J. Raza, A. Ruffolo, d. Sáiz, A. Saeed, M. Semikoz, d. Shao, L. Shchegolev, O. Sheng, X.d. Shu, F.W. Song, H.C. Stenkin, yu.V. Stepanov, V. Su, y. Sun, d.X. Sun, Q.n. Sun, X.n. Sun, Z.B. Takata, J. Tam, P.H.T. Key Laboratory of Particle Astrophysics & Experimental Physics division & Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of Chinese Academy of Sciences Beijing 100049 China TIAnFU Cosmic Ray Research Center Chengdu China dublin Institute for Advanced Studies 31 Fitzwilliam Place 2 Dublin Ireland Max-Planck-Institut for nuclear Physics P.O. Box 103980 Heidelberg 69029 Germany School of Physical Science and Technology & School of Information Science and Technology Southwest Jiaotong University Chengdu 610031 China School of Astronomy and Space Science Nanjing University Nanjing 210023 China Center for Astrophysics Guangzhou University Guangzhou 510006 China Tsung-dao Lee Institute & School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Institute for nuclear Research of Russian Academy of Sciences Moscow 117312 Russia Hebei normal University Shijiazhuang 050024 China University of Science and Technology of China Hefei 230026 China State Key Laboratory of Particle detection and Electronics China Key Laboratory of dark Matter and Space Astronomy & Key Laboratory of Radio Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210023 China Research Center for Astronomical Computing Zhejiang Laboratory Hangzhou 311121 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China School of Physics and Astronomy Yunnan University Kunming 650091 China Key Laboratory of Cosmic Rays (Tibet University) Ministry of Education Lhasa 850000 China national Astronomical Observatories Chinese Academy of Sciences Beijing 100101 China School of Physics and Astronomy (Zhuhai) & School of Physics (Guangzhou) & Sino-French Institute of nuclear Engineering and Technology (Zhuhai) Sun Yat-sen University Zhuhai 519000 & Guangzhou 510275 Guangdong China Institute of Frontier and

The γ-ray emission from the W51 complex is widely acknowledged to be attributed to the interaction between the cosmic rays (CRs) accelerated by the shock of supernova remnant (SnR) W51C and the dense molecular clouds in the adjacent star-forming region, W51B. However, the maximum acceleration capability of W51C for CRs remains elusive. Based on observations conducted with the Large High Altitude Air Shower Observatory (LHAASO), we report a significant detection of γ rays emanating from the W51 complex, with energies from 2 to 200 TeV. The LHAASO measurements, for the first time, extend the γ-ray emission from the W51 complex beyond 100 TeV and reveal a significant spectrum bending at tens of TeV. By combining the "π0-decay bump" featured data from Fermi-LAT, the broadband γ-ray spectrum of the W51 region can be well-characterized by a simple pp-collision model. The observed spectral bending feature suggests an exponential cutoff at ∼400 TeV or a power-law break at ∼200 TeV in the CR proton spectrum, most likely providing the first evidence of SnRs serving as CR accelerators approaching the PeV regime. Additionally, two young star clusters within W51B could also be theoretically viable to produce the most energetic γ rays observed by LHAASO. Our findings strongly support the presence of extreme CR accelerators within the W51 complex and provide new insights into the origin of Galactic CRs. © 2024 Science China Press

关键词： Cosmic rays

Influence of biomass burning on ozone levels in the Megalopolis of Central Mexico during the COVId-19 lockdown

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Journal of Environmental Sciences 2024年第9期143卷 99-115页

作者： Victor Almanza Luis Gerardo Ruiz-Suárez Ricardo Torres-Jardón Agustín García-Reynoso Iván y.Hernández-Paniagua Institute for Atmospheric Sciences and Climate Change National Autonomous University of MexicoCoyoacan 04510Mexico CityMexico

The massive reductions in anthropogenic emissions resulting from the COVId-19 lockdown provided a unique opportunity to evaluate the effect of mitigation measures aiming to abate air *** Mexico,the total lockdown period took place during the dry-hot season when biomass burning activity is ***,we investigate the role of biomass burning emissions on regional ozone levels in the Megalopolis of Central *** studied period covers the lockdown phases 2 and 3,and the first month of the new *** applied a factor separation technique and process analysis to estimate the pure and synergistic contributions of emission reductions under lockdown and that from biomass burning to daily ozone maximum concentrations in 7 metropolitan areas of different states in the *** results revealed that biomass burning plumes likely masked the effect of massive reductions from mobile emissions,impacted the PBL development during phase 3 and favored transition and mixed nO_(x)-limited and VOC-limited regional *** contributed to increased ozone production in the middle to lower PBL by changing the regional background levels which potentially could bias high ozone production efficiency *** the Megalopolis contribution to economic and societal development at national scale,our study suggests that ozone mitigation measures during the dry-hot season targeting mainly mobile emissions will likely be offset by biomass burning plumes.A regional and synergic policy aiming to control biomass burning would help to reduce the occurrence of high ozone levels in Central Mexico with the co-benefit of tackling short-lived climate pollutants.

关键词： COVId-19 Mexico Megalopolis Ozone Factor Separation Process Analysis