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971.
类水滑石衍生CuAlO催化剂同时去除碳颗粒和氮氧化物 总被引:2,自引:0,他引:2
以共沉淀法合成的含Cu类水滑石为前驱物, 制备了具有介孔结构的CuAlO复合氧化物催化剂, 采用程序升温反应技术评价了催化剂同时去除碳颗粒物(soot)和氮氧化物的性能, 并系统分析了反应条件对催化活性的影响. 结果表明, 在紧接触和松接触两种条件下, CuAlO都有较高的同时去除碳颗粒物和NOx的催化活性, 当催化剂与soot由紧接触变为松接触时, 起燃温度(Ti)由260 ℃升高到314 ℃, NO转化为N2的最大转化率(XN2-max)值由40.4%下降为29.2%; soot含量不同对Ti影响不大, Ti都在260 ℃左右; NO浓度或O2浓度增加, Ti下降, O2浓度从2.5%增至7.5%时对XN2-max影响不大, 都在40%左右; 反应气流速增大, soot起燃温度Ti基本不变, 都在260 ℃左右, 而XN2-max随气速增加而减小, 当气速从20 mL·min-1升至80 mL·min-1时, XN2-max由40.4%下降至21.6%, 但生成N2的量基本相同, 这取决于催化剂的选择性. 催化剂经重复使用后活性下降, 可能是由于反应过程中生成的中间产物吸附于催化剂表面, 覆盖了催化剂表面的活性位. 相似文献
972.
We analyze the finite element approximation of the spectral problem for the linear elasticity equation with mixed boundary conditions on a curved non-convex domain. In the framework of the abstract spectral approximation theory, we obtain optimal order error estimates for the approximation of eigenvalues and eigenvectors. Two kinds of problems are considered: the discrete domain does not coincide with the real one and mixed boundary conditions are imposed. Some numerical results are presented. 相似文献
973.
Hadi Mohammadi Bidhandi Rosnah Mohd. Yusuff Megat Mohamad Hamdan Megat Ahmad Mohd Rizam Abu Bakar 《European Journal of Operational Research》2009
This paper proposes a mixed integer linear programming model and solution algorithm for solving supply chain network design problems in deterministic, multi-commodity, single-period contexts. The strategic level of supply chain planning and tactical level planning of supply chain are aggregated to propose an integrated model. The model integrates location and capacity choices for suppliers, plants and warehouses selection, product range assignment and production flows. The open-or-close decisions for the facilities are binary decision variables and the production and transportation flow decisions are continuous decision variables. Consequently, this problem is a binary mixed integer linear programming problem. In this paper, a modified version of Benders’ decomposition is proposed to solve the model. The most difficulty associated with the Benders’ decomposition is the solution of master problem, as in many real-life problems the model will be NP-hard and very time consuming. In the proposed procedure, the master problem will be developed using the surrogate constraints. We show that the main constraints of the master problem can be replaced by the strongest surrogate constraint. The generated problem with the strongest surrogate constraint is a valid relaxation of the main problem. Furthermore, a near-optimal initial solution is generated for a reduction in the number of iterations. 相似文献
974.
This paper deals with the problems of checking strong solvability and feasibility of linear interval equations, checking weak solvability of linear interval equations and inequalities, and finding control solutions of linear interval equations. These problems are known to be NP-hard. We use some recently developed characterizations in combination with classical arguments to show that these problems can be equivalently stated as optimization tasks and provide the corresponding linear mixed 0–1 programming formulations. 相似文献
975.
We present a generalization of the mixed integer rounding (MIR) approach for generating valid inequalities for (mixed) integer
programming (MIP) problems. For any positive integer n, we develop n facets for a certain (n + 1)-dimensional single-constraint polyhedron in a sequential manner. We then show that for any n, the last of these facets (which we call the n-step MIR facet) can be used to generate a family of valid inequalities for the feasible set of a general (mixed) IP constraint, which we
refer to as the n-step MIR inequalities. The Gomory Mixed Integer Cut and the 2-step MIR inequality of Dash and günlük (Math Program 105(1):29–53, 2006) are the
first two families corresponding to n = 1,2, respectively. The n-step MIR inequalities are easily produced using periodic functions which we refer to as the n-step MIR functions. None of these functions dominates the other on its whole period. Finally, we prove that the n-step MIR inequalities generate two-slope facets for the infinite group polyhedra, and hence are potentially strong.
相似文献
976.
The mixed complementarity problem (denote by MCP(F)) can be reformulated as the solution of a smooth system of equations. In the paper, based on a perturbed mid function, we propose a new smoothing function, which has an important property, not satisfied by many other smoothing function. The existence and continuity of a smooth path for solving the mixed complementarity problem with a P0 function are discussed. Then we presented a one-step smoothing Newton algorithm to solve the MCP with a P0 function. The global convergence of the proposed algorithm is verified under mild conditions. And by using the smooth and semismooth technique, the rate of convergence of the method is proved under some suitable assumptions. 相似文献
977.
K.R. Kazmi B.S. Komal F.A. Khan Pankaj Mansotra 《Applied mathematics and computation》2009,215(2):716-726
In this paper, using the concept of P-η-proximal-point mapping introduced by Kazmi and Bhat [11], we study the existence and sensitivity analysis of the solution set of a system of parametric general quasi-variational-like inequality problems in uniformly smooth Banach spaces. Further under suitable conditions, we discuss the Lipschitz continuity of the solution set with respect to the parameters. The approach used in this paper may be treated as an extension and unification of approaches for studying sensitivity analysis for various important classes of variational inequalities given in [1,2,4,12,14–16,21–24]. 相似文献
978.
Weilin Chen Yangguang Li Dr. Yonghui Wang Enbo Wang Prof. Dr. Zhiming Zhang 《无机化学与普通化学杂志》2009,635(11):1678-1687
Employing a “one‐pot” synthesis strategy, the reaction of Na2WO4·2H2O, Na2HAsO4·7H2O, FeCl3·6H2O, various Ln3+ ions, and hexamethylenetetramine (HMTA) in aqueous solutions with pH values ranging from 5.5 to 6.5 results in the isolation of polytungstoarsenate‐based iron aggregates, ‐K8Na14[HMTA]4[(FeIII3FeII0.25(OH)3)(AsO4)(AsW9O34)]4·24H2O ( 1 ) (HMTA = hexamethylenetetraamine). The polyoxoanion of 1 contains a mixed‐valent {FeIII12FeII(μ3‐OH)12(μ4‐AsO4)4} cluster surrounded by four [B‐α‐AsW9O34]9? units. It is the first polytungstatoarsenate‐based mixed‐valent {FeIII12FeII} aggregate and the largest iron cluster based on [AsW9O34]9? ligands. The compound was characterized by elemental analyses, IR, UV/Vis absorption, and diffuse‐reflectance UV/Vis spectroscopy, TG analyses, XRPD, XPS and gel‐filtration chromatography. The electrochemical and electrocatalytical properties were also investigated. Crystal data for 1 , orthorhombic, Fddd, a = 28.156(6) Å, b = 36.003(7) Å, c = 42.126(8) Å, α = 90°, β = 90°, γ = 90°, Z = 8. 相似文献
979.
The brown crystals of [PMePh3]2[Se2Br6] ( 1 ) and red crystals of [PMePh3]2[SeBr6(SeBr2)2] ( 2 ) were obtained when selenium and bromine reacted in the solution of acetonitrile in the presence of methyltriphenylphosphonium bromide. The crystal structures of 1 and 2 has been determined by the X‐ray methods and refined to R = 0.0373 for 2397 reflections and 0.0397 for 3417 reflections, respectively. The salt 1 crystallizes in the monoclinic space group P21/n with the cell dimensions a = 13.202(5) Å, b = 11.954(4) Å, c = 13.418(6) Å, β = 93.08(4)° (193(2)). The crystals of 2 are triclinic, space group with the cell dimensions a = 10.266(3) Å, b = 11.311(3) Å, c = 11.619(2) Å, α = 108.87(2)°, β = 105.72(2)°, γ = 99.40(2)° (193(2) K). In the solid state structure of 1 the dinuclear hexabromo‐diselenate(II) anion is centrosymmetric and consists of two distorted almost square planar SeBr4 units sharing a common edge through two μ‐bridging Br atoms. The terminal SeII–Br bonds are 2.3984(11) and 2.4273(11) Å, whereas the bridging μBr–SeII bonds are 2.7817(11) and 2.9081(12) Å. In the solid state the trinuclear [SeBr6(SeBr2)2]2? anion of 2 is centrosymmetric too and contains a nearly regular [SeBr6] octahedron where the four equatorial bromo ligands each have developed bonds to the SeII atoms of the SeBr2 molecules. The contacts between the bridging bromo and the SeII atoms of the SeBr2 molecules are 3.0603(15) and 3.1043(12) Å, and can be interpreted as bonds of the donor‐acceptor type with the bridging bromo ligands as donors and the SeBr2 molecules as acceptors. The SeIV–Br distances are in the range 2.5570(9)–2.5773(11) Å and the SeII–Br bond lengths in coordinated SeBr2 molecules – 2.3411(12) and 2.3421(10) Å. 相似文献
980.
The reaction of octamethylenetetrathiafulvalene (OMTTF) with excess CuBr2 in tetrahydrofurane/acetonitrile yields black (OMTTF)2[Cu4Br10] ( 1 ). The crystal structure determination shows the presence of OMTTF cations and tetranuclear bromidocuprate anions. The novel anion consists of four edge and corner sharing CuBr4 tetrahedra, which are connected to a ring. The assignment of the ionic charges and oxidation states for the copper atoms is supported by the magnetic properties. 1 is antiferromagnetic with TN ≈ 30 K. The magnetic moment reaches 2.54 B.M., which indicates, together with the Curie–Weiss constant of –35 K, a coupling of the paramagnetic spins over the whole temperature region. The ionic charges of the salt‐like compound 1 are therefore (OMTTF2+)2[(Cu+)2(Cu2+)2Br10]4–. The antiferromagnetism is explained by the coupling of the spins of two Cu2+ ions in the anion with an exchange constant of J = –18 cm–1. The CuI and CuII atoms are clearly distinguishable in the mixed valent anion. The OMTTF cation is not planar but exhibits an interplanar angle between the two central C3S2 ring moieties of 15.3°, which is in accordance to the dicationic oxidation state. 相似文献