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Fe-n-C core-shell catalysts with single low-spin Fe(Ⅱ)-n_(4)species for oxygen reduction reaction and high-performance proton exchange membr.ne fuel cells

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Journal of Energy Chemistry 2024年第6期93卷 538-546,I0013页

作者： Yan Wan linhui Yu Bingxin Yang Caihong Li Chen Fang Wei Guo Fang-Xing Xiao Yangming lin Xiamen Key Laboratory of rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstituteChinese Academy of SciencesXiamen 361021FujianChina CAS Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021FujianChina Fujian Institute of research on the Structure of Matter Chinese Academy of SciencesFuzhou 350002FujianChina College of Materials Science and Engineer.ng Fuzhou UniversityNew CampusMinhou 350108FujianChina College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350117FujianChina

Fe-n-doped carbon materials(Fe-n-C)are promising candidates for oxygen reduction reaction(Orr)relative to Pt-based catalysts in proton exchange membr.ne fuel cells(PEMFCs).However,the intr.nsic contributions of Fe-n_(4)moiety with differ.nt chemical/spin states(e.g.D1,D2,D3)to Orr are unclear since various states coexist *** the present work,Fe-n-C core-shell nanocatalyst with single lowspin Fe(Ⅱ)-n_(4)species(D1)is synthesized and identified with ex-situ ultralow temperature Mossbauer spectroscopy(T=1.6 K)that could essentially differ.ntiate various Fe-n_(4)states and invisible Fe-O *** quantifying with CO-pulse chemisorption,site density and turnover frequency of Fe-n-C catalysts reach 2.4×10^(-9)site g^(-1)and 23 e site~(-1)s^(-1)dur.ng the Orr,***-wave potential(0.915V_(rHE))of the Fe-n-C catalyst is more positive(approximately 54 mV)than that of Pt/***,we observe that the performance of PEMFCs on Fe-n-C almost achieves the 2025 target of the US Department of Energy by demonstrating a curr.nt density of 1.037 A cm^(-2)combined with the peak power density of 0,685 W cm^(-2),suggesting the critical role of Fe(Ⅱ)-n_(4)site(D1).After 500 h of r.nning,PEMFCs still deliver a power density of 1.26 W cm^(-2)at 1.0 bar H_(2)-O_(2),An unexpected rate-determining step is figured out by isotopic labelling experiment and theoretical *** work not only offers valuable insights regarding the intr.nsic contribution of Fe-n_(4)with a single spin state to alkaline/acidic Orr,but also provides great opportunities for developing high-performance stable PEMFCs.

关键词： Fuel cells Oxygen reduction reaction non-platinum group metals(PGMs) Isotopic labelling Active site TOF

Tuning interface mechanism of FeCo alloy embedded n,S-codoped carbon substrate for rechargeable Zn-air battery

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Journal of Energy Chemistry 2024年第6期93卷 400-410,I0010页

作者： Hui Chang Lulu Zhao Shan Zhao Zong-lin Liu Peng-Fei Wang Ying Xie Ting-Feng Yi School of Materials Science and Engineer.ng Northeastern UniversityShenyang 110819LiaoningChina Key Laboratory of Functional Inorganic Material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080HeilongjiangChina Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province School of Resources and MaterialsNortheastern University at QinhuangdaoQinhuangdao 066004HebeiChina

The interface mechanism between catalyst and carbon substrate has been the focus of *** this paper,the FeCo alloy embedded n,S co-doped carbon substrate bifunctional catalyst(FeCo/S-nC)is obtained by a simple one-step pyrolysis *** experimental results and density functional theory(DFT)calculation show that the formation of FeCo alloy is conducive to promoting electr.n tr.nsfer,and the introduction of S atom can enhance the interaction between FeCo alloy and carbon substrate,thus inhibiting the migration and agglomeration of particles on the surface of carbon *** FeCo/SnC catalysts show outstanding performance for oxygen reduction reaction(Orr)and oxygen evolution reaction(OEr).FeCo/S-nC shows a high half-wave potential(E_(1/2)=0.8823 V)for Orr and a low overpotential at 10 mA cm^(-2)(E_(j=10)=299 mV)for *** addition,compared with Pt/C+ruO_(2) assembled Zn-air battery(ZAB),the FeCo/S-nC assembled ZAB exhibits a larger power density(198.8 mW cm^(-2)),a higher specific capacity(786.1 mA h g_(zn)~(-1)),and ultra-stable cycle *** results confirm that the optimized composition and the interfacial interaction between catalyst and carbon substrate synergistically enhance the electrochemical performance.

关键词： FeCo alloy n S co-doped carbon DFT calculation Zn-air batteries Interfacial interaction

Study on the optimal incident proton energy of ^(7)Li(p,n)^(7)Be neutr.n source for bor.n neutr.n capture therapy

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nuclear Science and Techniques 2024年第3期35卷 170-180页

作者： Yi-nan Zhu Zuo-Kang lin Hai-Yan Yu Ye Dai Zhi-Min Dai Xiao-Han Yu Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Science Beijing 100049China

Bor.n neutr.n capture therapy(BnCT)is recognized as a precise binary targeted radiotherapy technique that effectively eliminates tumors through the^(10)B(n,α)^(7)Li nuclear *** various neutr.n sources,accelerator-based sources have emerged as particularly promising for BnCT ***^(7)Li(p,n)^(7)Be reaction is highly regarded as a potential neutr.n source for BnCT,owing to its low threshold energy for the reaction,significant neutr.n yield,appropriate average neutr.n energy,and additional *** study utilized Monte Carlo simulations to model the physical interactions within a lithium target subjected to proton bombardment,including neutr.n moderation by an MgF_(2)moderator and subsequent BnCT dose analysis using a Snyder head *** study focused on calculating the yields of epithermal neutr.ns for various incident proton energies,finding an optimal energy at 2.7 ***,the Snyder head phantom was employed in dose simulations to validate the effectiveness of this specific incident energy when utilizing a^(7)Li(p,n)^(7)Be neutr.n source for BnCT purposes.

关键词： Bor.n neutr.n capture therapy ^(7)Li(p,n)7Be neutr.n source Incident proton energy Monte Carlo simulation

A concise review on surface and structural modification of porous zeolite scaffold for enhanced hydrogen storage

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Chinese Journal of Chemical Engineer.ng 2024年第6期70卷 33-53页

作者： B.A.Abdulkadir r.S.r.Mohd Zaki A.T.Abd Wahab S.n.Miskan Anh-Tam nguyen Dai-Viet n.Vo H.D.Setiabudi Centre for research in Advanced Fluid&Processes Universiti Malaysia Pahang Al-Sultan AbdullahLebuh Persiaran Tun Khalil YaakobGambangPahang 26300Malaysia Faculty of Chemical&Process Engineer.ng Technology Universiti Malaysia Pahang Al-Sultan AbdullahLebuh Persiaran Tun Khalil YaakobGambangPahang 26300Malaysia Center of Excellence for Green Energy and Envir.nmental nanomaterials(CE@GrEEn) Nguyen Tat Thanh University300A Nguyen Tat ThanhDistrict 4Ho Chi Minh City 755414Viet Nam

Investigating zeolites as hydrogen storage scaffolds is imperative due to their porous nature and favorable physicochemical ***,the storage capacity of the unmodified zeolites has been rather unsatisfactory(0.224%-1.082%(mass))compared to its modified ***,the contemporary focus on enhancing hydrogen storage capacities has led to significant attention towards the utilization of modified zeolites,with studies explor.ng surface modifications through physical and chemical treatments,as well as the integration of various active *** enhanced hydrogen storage properties of zeolites are attributed to the presence of aluminosilicates from alkaline and alkaline-earth metals,resulting in increased storage capacity through interactions with the charge density of these ***,there is a great demand to critically review their role such as well-defined topology,pore structure,good thermal stability,and tunable hydrophilicity in enhanced hydrogen *** article aimed to critically review the recent research findings based on modified zeolite performance for enhanced hydrogen *** of the factors affecting the hydrogen storage capacities of zeolites that can affect the rate of reaction and the stability of the adsorbent,like pressure,structure,and morphology were studied,and ***,future perspectives,recommendations,and directions for modified zeolites were discussed.

关键词： Zeolites Hydrogen storage Surface modification Adsorption Active metal

On the Probability of Generating a Primitive Matrix

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Journal of Systems Science & Complexity 2024年第4期37卷 1755-1771页

作者： CHEn Jingwei FEnG yong LIU Yang WU Wenyuan Chongqing Key Laboratory of Automated reasoning and Cognition Chongqing Institute of Green and Intelligent TechnologyChinese Academy of SciencesChongqing 400714China Chongqing College University of Chinese Academy of SciencesChongqing 400714China Key Laboratory of Advanced Manufactur.ng Technology of Ministry of Education Guizhou UniversityyGuiyang 550025China Information Science and Engineer.ng Chongqing Jiaotong UniversityChongqing 400074China

Given a k×n integer primitive matrix A(i.e.,a matrix can be extended to an n×n unimodular matrix over the integers)with the maximal absolute value of entries‖A‖bounded by an integer λ from above,the authors study the probability that the m×n matrix extended from A by appending other m-k row vectors of dimension n with entries chosen r.ndomly and independently from the uniform distribution over{0,1,…,λ-1}is still *** authors present a complete and rigorous proof of a lower bound on the probability,which is at least a constant for fixed m in the r.nge[k+1,n-4].As an application,the authors prove that there exists a fast Las Vegas algorithm that completes a k×n primitive matrix A to an n×n unimodular matrix within expected O(n^(ω)log‖A‖)bit operations,where O is big-O but without log factors,ω is the exponent on the arithmetic operations of matrix multiplication.

关键词： Integer matrix matrix completion probabilistic algorithm unimodular matrix

Two ramsey-Tur.n numbers of Small Independence numbers

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Acta Mathematicae Applicatae Sinica 2024年

作者： Xin-yu HU Qi-zhong lin Center for Discrete Mathematics Fuzhou University

Given a forbidden graph H and a function f(n), the ramsey-Tur.n number rT (n, H, f (n)) is the maximum number of edges of an H-free graph on n vertices with independence number less than f (n).For graphs G and H, the ramsey number r(G, H) is the minimum integer.n such that any red/blue edge color.ng of the complete graph Kncontains either a red G or a blue H. Denote G+H by the join graph obtained from disjoint G and H by adding all edges between them completely. We first show that for any fixed graph H, if there are two constants p:=p(H)> 0 and q:=q(H)> 1 such that r(H, Kn)≤(pnq)/(log n)q-1, then rT(n, K2+H, o(n1/q(log n)1-1/q))=o(n2), which extends several previous results. Moreover, we show that for any fixed forest F of order k≥3, and for any 0 nd sufficiently large n, rT(n, F+F, nδ)≤n(2-(1-δ)/「(k-1)(2-δ)/(1-δ)」).As a corollary, we have an upper bound for rT(n, K2,2,2, nδ) for any 0 <δ <1.

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Ion heat tr.nsport in electr.n cyclotr.n resonance heated L-mode plasma on the T-10 tokamak

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Plasma Science and Technology 2024年第4期26卷 52-60页

作者： V.A.KrUPIn M.r.nUrGALIEV A.r.nEMETS I.A.ZEMTSOV S.D.SUnTSOV T.B.MYALTOn D.S.SErGEEV n.A.SOLOVEV D.V.SArYCHEV D.V.rYJAKOV S.n.TUGAr.nOV n.n.nAUMEnKO national research Centre“Kurchatov Institute” Moscow 123182Russia Bauman Moscow State Technical University Moscow 105005Russia Institution“Project Center ITEr” Moscow 123098Russia JSC“SOLAr” Minsk 220034Belarus

Anomalous ion heat tr.nsport is analyzed in the T-10 tokamak plasma heated with electr.n cyclotr.n resonance heating(ECrH) in second-harmonic extra-ordinary mode. Predictive modeling with empirical scaling for Ohmical heat conductivity shows that in ECrH plasmas the calculated ion temperature could be overestimated, so an increase of anomalous ion heat tr.nsport is required. To study this effect two scans are presented: over the EC resonance position and over the ECrH power. The EC resonance position varies from the high-field side to the low-field side by variation of the toroidal magnetic field. The scan over the heating power is presented with on-axis and mixed ECrH regimes. Discharges with high anomalous ion heat tr.nsport are obtained in all considered regimes. In these discharges the power balance ion heat conductivity exceeds the neoclassical level by up to 10 times. The high ion heat tr.nsport regimes are distinguished by three parameters: the ratio Te/Ti, the normalized electr.n density gradient r/■, and the ion–ion collisionality νii~*. The combination of high Te/Ti, high νii~*, and r/■=6-10 results in values of normalized anomalous ion heat fluxes up to 10 times higher than in the low tr.nsport scenario.

关键词： tokamak L-mode electr.n cyclotr.n resonance heating ion heat tr.nsport

Standardized ileal digestibility of amino acids in soybean meal fed to non-pregnant and pregnant sows

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Journal of Animal Science and Biotechnology 2024年第1期15卷 362-373页

作者： Ke Wang Ya Wang Lei Guo yong Zhuo Lun Hua Lianqiang Che Shengyu Xu ruinan Zhang Jian Li Bin Feng Zhengfeng Fang Xuemei Jiang Yan lin De Wu Institute of Animal nutrition Key Laboratory for Animal Disease‑Resistance Nutrition of ChinaMinistry of EducationSichuan Agricultural University211 Huimin RoadWenjiang DistrictChengdu 611130SichuanChina

Background Two studies were designed to determine standard ileal crude protein(CP)and amino acid(AA)digestibility of soybean meal(SBM)from differ.nt origins fed to non-pregnant and pregnant *** solvent-extracted SBMs from soybeans produced in the USA,Brazil,and China were *** Exp.1,eight differ.nt diets were created:a nitrogen(n)-free diet and 7 experimental diets containing SBM from differ.nt origins as the only n *** non-pregnant,multiparous sows were arr.nged in an 8×8 Latin square design(8 periods and 8 diets).In Exp.2,the diet formula was the same as in *** gestating sows(parity 3)were assigned to 4 differ.nt diets in a replicated 4×3 Youden square design(three periods and four diets)in mid-gestation and again in late-gestation *** When fed to non-pregnant and late-gestating sows,the standardized ileal digestibility(SID)of CP and most AAs from differ.nt SBM were not significantly differ.nt(P>0.05).When fed to mid-gestating sows,the SID values for Arg,His,Lys,Phe,Cys,Gly,Ser,and Tyr in SBM 1 were lower than in SBM 4 and 5(Preas SID for Leu from SBM 5 was higher than in SBM 1 and 4(Pr Ile,Ala,and Asp from SBM 4 were lower than in SBM 1 and 5(Pnificantly greater SID values for Lys,Ala,and Asp dur.ng mid-gestation when compared with late-gestation stages(Png sows had greater SID value for Val and lower SID value for Tyr when compared with non-pregnant and late-gestating sows(Preas non-pregnant sows had significantly greater SID value for Met when compared with gestating sows(Pnclusions When fed to mid-gestating sows,the SID values for most AAs varied among SBM *** SID values for Lys,Met,Val,Ala,Asp,and Tyr in SBM were affected by sow gestation *** findings provide a cornerstone for accurate SBM use in sow diets.

关键词： Amino acids Sows Soybean meal Standardized ileal digestibility

Study of primordial deuterium abundance in Big Bang nucleosynthesis

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nuclear Science and Techniques 2024年第3期35卷 208-215页

作者： Zhi-lin Shen Jian-Jun He Key Laboratory of Beam Technology of Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Institute of radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China

Big Bang nucleosynthesis(BBn)theory predicts the primordial abundances of the light elements^(2) H(referred to as deuterium,or D for short),^(3)He,^(4)He,and^(7) Li produced in the early *** these,deuterium,the first nuclide produced by BBn,is a key primordial material for subsequent *** date,the uncertainty in predicted deuterium abundance(D/H)remains larger than the observational *** this study,the Monte Carlo simulation code PrIMAT was used to investigate the sensitivity of 11 important BBn reactions to deuterium *** found that the reaction rate uncertainties of the four reactions d(d,n)^(3)He,d(d,p)t,d(p,γ)^(3)He,and p(n,γ)d had the largest influence on the calculated D/H ***,the calculated D/H uncertainty cannot reach observational precision even with the recent LUnA precise d(p,γ)^(3) He *** the nuclear physics aspect,there is still room to largely reduce the reaction-rate uncertainties;hence,further measurements of the important reactions involved in BBn are still necessary.A photodisintegration experiment will be conducted at the Shanghai Laser Electr.n Gamma Source Facility to precisely study the deuterium production reaction of p(n,γ)d.

关键词： Big Bang nucleosynthesis Abundance of deuterium reaction cross section reaction rate Monte Carlo method