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Effect of tungsten oxide on ceria nanorods to support copper species as CO oxidation catalysts

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Journal of Rare Earths 2021年第1期39卷 43-50,I0002页

作者： Yu'nan Li Lin Gan Rui si Hubei Collaborative innovation Center for Advanced Organic Chemical Materials Ministry of Education Key Laboratory for the Green Preparation and Application of Functional Materials and School of Material Science and EngineeringHubei UniversityWuhan 430062China Zhangjiang Laboratory Shanghai Synchrotron Radiation FacilityShanghai 201204China

in this work,tungsten oxide with different concentrations(0,0.4 at%,2.0 at%and 3.2 at%)was introduced to the ceria nanorods via a deposition-precipitation(DP)approach,and copper species of ca.10 at%were sequentially anchored onto the modified ceria support by a similar DP *** aim of the study was to investigate the effect of the amount of tungsten oxide(0,0.4 at%,2.0 at%,and 3.2 at%)modifier on the copper-ceria catalysts for CO oxidation reaction and shed light on the structure-activity *** the aids of multiple characterization techniques including n2 adsorption,high-resolution transmission electron microscopy(HRTEM),powder X-ray diffraction(XRD),X-ray absorption fine structure(XAFS),and temperature-programmed reduction by hydrogen(H2-TPR)in combination with the catalytic performance for CO oxidation reaction,it is found that the copper-ceria samples maintain the crystal structure of the fluorite fcc CeO2 phase with the same nanorod-like morphology with the introduction of tungsten oxide,while the textural properties(the surface area,pore volume and pore size)of ceria support and copper-ceria catalysts are changed,and the oxidation states of copper and tungsten are kept the same as Cu2+and W6+before and after the reaction,but the introduction of tungsten oxide(WO3)significantly changes the metal-support interaction(transfer the CuOx clusters to Cu-[Ox]-Ce species),which delivers to impair the catalytic activity of copper-ceria catalysts for CO oxidation reaction.

关键词： Copper catalyst Ceria Tungsten oxide CO oxidation Structure-activity relationship Rare earths

Characteristics of nO reduction with non-thermal plasma

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Journal of Environmental Sciences 2005年第4期17卷 627-630页

作者： YUGang YUQi JiAnGYan-long ZEnGKe-si DepartmentofMan-MachineandEnvironmentEngineering CollegeofAerospaceEngineeringNanjingUniversityofAeronauticsandAstronauticsljing210016China DepartmentofEnvironmentalandChemicalEngineering WuhanInstituteofScienceandTechnologyWuhan430074China

As a new type of nO removal system, nO reduction in n_2-nO plasma was applied to solve the difficulties in the traditional methods, such as higher energy-consumption, larger equipment size and high cost, and so on. Using the experimental nO reduction system with single-pair electrode tip discharge structure, the nO reduction characteristics of n_2-nO system were revealed to guide the engineering practice; the results of nO reduction with single-pair electrode tip discharge plasma also have the same instructive meaning to the nO reduction with multi-pair electrode tip discharge plasma. The amount of both active n atom and nO removal rate increased with the distance l_g increasing between the two electrode tips and then dropped when the distance exceeded a certain value. The nO removal rate increased while the voltage between two electrode tips or the resident time of gas flow increased. The distance is a key geometrical variable factor that can determine the intensity of electric field between two electrode tips and the resident time of gas. in this paper, the effects of the dielectric features on nO reduction using dielectric-barrier discharge plasma system were also studied. The results of nO removal rate with different dielectrics such as Al_2O_3, CaO, MgO and glass showed that the electric field intensity is different with different dielectric, because it brings different energy to particles in discharge room and thus it causes different nO removal rate.

关键词： nO reduction plasma characteristic single-pair electrode tip discharge dielectric-barrier discharge

Composition Cesàro Operator on the normal Weight Zygmund Space in High Dimensions

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Chinese Annals of Mathematics,Series B 2021年第1期42卷 69-84页

作者： si XU Xuejun ZHAnG Shenlian Li College of Mathematics and Statistics Hunan Normal UniversityChangsha 410006China

Let n>1 and B be the unit ball in n dimensions complex space C^(n).Suppose thatφis a holomorphic self-map of B andψ∈H(B)withψ(0)=0.A kind of integral operator,composition Cesàro operator,is defined by T_(φ)ψ(f)(z)=∫^(1)0f[φ(tz)]Rψ(tz)dt/t,f∈(B)z∈*** this paper,the authors characterize the conditions that the composition Cesàro operator T_φ,ψis bounded or compact on the normal weight Zygmund space Z_μ(B).At the same time,the sufficient and necessary conditions for all cases are given.

关键词： normal weight Zygmund space Composition Cesàro operator Boundedness and compactness

On the bilinear square Fourier multiplier operators and related multilinear square functions

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Science China Mathematics 2017年第8期60卷 1477-1502页

作者： si ZengYan XUE QingYing YABUTA Kz School of Mathematics and information Science Henan Polytechnic University School of Mathematical Sciences Beijing Normal UniversityLaboratory of Mathematics and Complex Systems Ministry of Education Research Center for Mathematical Sciences Kwansei Gakuin University

Let n 1 and Tm be the bilinear square Fourier multiplier operator associated with a symbol m,which is defined by Tm（f1, f2）（x） =（∫0^∞︱∫（Rn）^2）e^2πix·（ξ1＋ξ2））m（tξ1, tξ2）f1（ξ1）f2（ξ2）dξ1dξ2︱^2dt/t）^1/2.Let s be an integer with s ∈ [n ＋ 1, 2n] and p0 be a number satisfying 2n/s p0 2. Suppose that νω=∏i^2=1ω^i^p/p） and each ωi is a nonnegative function on Rn. in this paper, we show that under some condition on m, Tm is bounded from L^p1（ω1） × L^p2（ω2） to L^p（νω） if p0 〈 p1, p2 〈 ∞ with 1/p = 1/p1 ＋ 1/p2. Moreover,if p0 〉 2n/s and p1 = p0 or p2 = p0, then Tm is bounded from L^p1（ω1） × L^p2（ω2） to L^p,∞（νω）. The weighted end-point L log L type estimate and strong estimate for the commutators of Tm are also given. These were done by considering the boundedness of some related multilinear square functions associated with mild regularity kernels and essentially improving some basic lemmas which have been used before.

关键词： multilinear square functions Fourier multiplier operator multiple weights commutators

isolated Toughness and k-Hamiltonian[a,b]-factors

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Acta Mathematicae Applicatae sinica 2020年第3期36卷 539-544页

作者： Zhi-ren SUn si-zhong ZHOU School of Mathematical Sciences Nanjing Normal UniversityNanjing 210046China School of Science Jiangsu University of Science and TechnologyMengxi Road 2Zhenjiang 212003China

Let a,b and k be nonnegative integers with a≥2 and b≥a(k+1)+2.A graph G is called a k-Hamiltonian graph if after deleting any k vertices of G the remaining graph of G has a Hamiltonian cycle.A graph G is said to have a k-Hamiltonian[a,b]-factor if after deleting any k vertices of G the remaining graph of G admits a Hamiltonian[a,b]-*** G is a k-Hamiltonian graph of order n with n≥a+k+*** this paper,it is proved that G contains a k-Hamiltonian[a,b]-factor ifδ(G)≥a+k andδ(G)≥i(G)≥a-1+(a(k+1))/(b-2).

关键词： isolated toughness k-Hamiltonian graph k-Hamiltonian[a b]-factor

The Thickness of Some Complete Bipartite and Tripartite Graphs

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Acta Mathematicae Applicatae sinica 2024年第4期40卷 1001-1014页

作者： si-wei HU Yi-chao CHEn Yali Peicui School Changsha 410021China School of Mathematics Suzhou University of Science and TechnologySuzhou 215009China

in this paper,we obtain the thickness for some complete k-partite graphs for k=2,*** first compute the thickness of K_(n,n+8)by giving a planar decomposition of K_(4k-1,4k+7)for k≥***,two planar decompositions for K_(1,g,g)(g-1)when g is even and for K^(1,g,1/2(g-1)2)when g is odd are *** a recursive construction,we also obtain the thickness for some complete tripartite *** results here support the long-standing conjecture that the thickness of K_(m,n)is[mn/2(m+n-2)]for any positive integers m,n.

关键词： thickness complete bipartite graph complete tripartite graph planar decomposition

Crystal structures and hydrogenation behavior of (Ca_(0.9)Sr_(0.1))_8(Al_(1-x)Zn_x)_3 alloys

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Rare Metals 2008年第2期27卷 134-137页

作者： si Tingzhi YAnG Weiming ZHAnG Qing＇an School of Materials Science and Engineering Anhui University of Technology Maanshan 243002 China

The crystal structures and hydrogenation behavior of the （Ca0.9Sr0.1）8（Al1-xZnx）3 （x = 0, 0.1, 0.2, 0.3 and 0.4） alloys were investigated. The new phase （Ca,Sr）E（Al,Zn） was found whenx 〉 0.1. （Ca, Sr）E（Al,Zn） crystallizes in space group 14/mmm （A-139）. The lattice parameters were calculated to be a = b = 1.1616（2） nm, c = 1.6422（4） nm. Zn atoms occupy the 8h and 16n sites together with Al atoms. The （Ca0.9Sr0.1）8Al3 alloy only contains a single Ca8Al3 phase. The （Ca0.9Sr0.1）8（Al1-xZnx）3 alloys consist of Ca8Al3, CasZn3, Ca and （Ca,Sr）2（Al,Zn） phases when x is from 0.1 to 0.3. As x increasing to 0.4, the alloy consists of （Ca,Sr）E（Al,Zn）, Ca8Zn3 and Ca. The hydrogenated （Ca0.9Sr0.1）8Al3 and （Ca0.9Sr0.1）8（Al0.9Zn0.1）3 samples consist of CartE and Al. The （Ca0.9Sr0.1）8（Al1-xZnx）3 （x = 0.2, 0.3 and 0.4） samples can be hydrogenated into CaH2, Al and CaZnl3 under a hydrogen pressure of 5 MPa at 473 K.

关键词： calcium-based alloys crystal structure X-ray diffraction hydrogenation behavior.

Some Existence Theorems on Path Factors with Given Properties in Graphs

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Acta Mathematica sinica,English Series 2020年第8期36卷 917-928页

作者： si Zhong ZHOU Zhi Ren SUn School of Science Jiangsu University of Science and TechnologyZhenjiang 212003P.R.China School of Mathematical Sciences Nanjing Normal UniversityNanjing 210046P.R.China

A path factor of G is a spanning subgraph of G such that its each component is a path.A path factor is called a P≥n-factor if its each component admits at least n vertices.A graph G is called P≥n-factor covered if G admits a P≥n-factor containing e for any e∈E(G),which is defined by[Discrete Mathematics,309,2067-2076(2009)].We first define the concept of a(P≥n,k)-factor-critical covered graph,namely,a graph G is called(P≥n,k)-factor-critical covered if G-D is P≥n-factor covered for any D⊆V(G)with|D|=*** this paper,we verify that(i)a graph G withκ(G)≥k+1 is(P≥2,k)-factor-critical covered if bind(G)>2+k/3;(ii)a graph G with|V(G)|≥k+3 andκ(G)≥k+1 is(P≥3,k)-factor-critical covered if bind(G)≥4+k/3.

关键词： Graph binding number P≥2-factor P≥3-factor (P≥2,k)-factor-critical covered graph (P≥3,k)-factor-critical covered graph

B_(111),B_(112),_(B113),and B_(114):The most stable core-shell borospherenes with an icosahedral B_(12) core at the center exhibiting superatomic behaviors

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nano Research 2021年第12期14卷 4719-4724页

作者： Min Zhang Hai-Gang Lu si-Dian Li institute of Molecular Science Shanxi UniversityTaiyuan030006China

Boron allotropes are known to be predominately constructed by icosahedral B_(12) cages,while icosahedral-B_(12) stuffing proves to effectively improve the stability of fullerene-like boron nanoclusters in the size range between B_(98)–B_(102).However,the thermodynamically most stable core-shell borospherenes with a B_(12) icosahedron at the center still remains *** on the structural motif of D5h C_(70) and extensive first-principles theory calculations,we predict herein the high-symmetry C5v B111+(3)which satisfies the Wade’s n+1 and n+2 skeletal electron counting rules exactly and the approximately electron sufficient Cs B_(111)(4),Cs B_(112)(5),Cs B_(113)(6),and Cs B_(114)(7)which are the most stable neutral core-shell borospherenes with a B_(12) icosahedron at the center reported to date in the size range between B_(68)–B_(130),with Cs B112(5)being the thermodynamically most favorite species in the *** orbital and bonding analyses indicate that these spherically aromatic species all contain a negatively charged icosahedral B_(122)−core at the center which exhibits typical superatomic behaviors in the electronic configuration of 1S21P61D101F8,with its dangling valences saturated by twelve radial B-B 2c-2eσbonds between the B_(12) inner core and the B_(70) outer *** infrared(iR)and Raman spectra of the concerned species are computationally simulated to facilitate their future characterizations.

关键词： first-principles theory borospherenes structures bonding superatomic behaviors spherical aromaticity