用0—1整数规划方法选择煤炭行业最优规划方案

文章基于采矿技术原理，运用０－１整数规划的数学方法，通过考察区域煤炭行业生产建设的总投资、总产量、总效益、安全程度这四者的相互制约关系，以求在有限投资条件下尽可能满足总产量和安全程度要求而需资金最少，产出投入比最大的最优规划方案。     

An upwind-mixed method on changing meshes for two-phase miscible flow in porous media

Two-phase miscible flow in porous media is governed by a system of nonlinear partial differential equations. In this paper, the upwind-mixed method on dynamically changing meshes is presented for the problem in two dimensions. The pressure is approximated by a mixed finite element method and the concentration by a method which upwinds the convection and incorporates diffusion using an expanded mixed finite element method. The method developed is shown to obtain almost optimal rate error estimate. When the method is modified we can obtain the optimal rate error estimate that is well known for static meshes. The modification of the scheme is the construction of a linear approximation to the solution, which is used in projecting the solution from one mesh to another. Finally, numerical experiments are given.     

虚拟企业管理中的伙伴选择问题:模型与理论分析

本文建立了虚拟企业伙伴选择问题的整数规划模型，并从理论上证明了该类问题正规解的存在性．所获结果对于该类问题的研究与求解提供了可靠的理论依据，并将建立的模型和所得结论应用到一个工程实际问题，采用遗传算法求解，取得了满意的计算结果．     

空间中混合单调脉冲微分-积分方程解的存在性

利用两个新的比较结果，本文给出了Banach空间中混合单调脉冲微分-积分方程解，最小最大耦合解的存在性及单调迭代方法，改进和推广了[1-5]的相应结果．     

Valid inequalities for mixed integer linear programs

This tutorial presents a theory of valid inequalities for mixed integer linear sets. It introduces the necessary tools from polyhedral theory and gives a geometric understanding of several classical families of valid inequalities such as lift-and-project cuts, Gomory mixed integer cuts, mixed integer rounding cuts, split cuts and intersection cuts, and it reveals the relationships between these families. The tutorial also discusses computational aspects of generating the cuts and their strength. Supported by NSF grant DMI-0352885, ONR grant N00014-03-1-0188 and ANR grant BLAN06-1-138894.     

An exact approach for the maximum concurrent k-splittable flow problem

We consider the maximization of a multicommodity flow throughput in presence of constraints on the maximum number of paths to be used. Such an optimization problem is strongly NP-hard, and is known in the literature as the maximum routable demand fraction variant of the k-splittable flow problem. Here we propose an exact approach based on branch and bound rules and on an arc-flow mixed integer programming formulation of the problem. Computational results are provided, and a comparison with a standard commercial solver is proposed.     

Sufficiency and duality in differentiable multiobjective programming involving generalized type I functions

In this paper, new classes of generalized (F,α,ρ,d)-type I functions are introduced for differentiable multiobjective programming. Based upon these generalized functions, first, we obtain several sufficient optimality conditions for feasible solution to be an efficient or weak efficient solution. Second, we prove weak and strong duality theorems for mixed type duality.     

Dependence of NO<Subscript>2</Subscript> sensitivity on thickness of oxide-sensing electrodes for mixed-potential-type sensor using stabilized zirconia

The effect of thickness of oxide-sensing electrode (SE) on NO₂ sensitivity of the planar sensor based on yttria-stabilized zirconia (YSZ) was examined at high temperatures. The sensitivity of the sensor increased with decreasing thickness of SE, and the highest sensitivity was obtained by using the thinnest layer of Cr₂O₃–SE (2.7 μm) at 700 °C. In the case of NiO–SE, the highest sensitivity was observed for the sensor using the 4 μm-thick SE even at high temperature of 850 °C. Based on the results of the measurements for the complex impedances, the polarization curves, and the gas-phase NO₂ decomposition catalysis, it was confirmed that the catalytic activity to the gas-phase NO₂ decomposition on the oxide–SE matrix played an important role in determining the NO₂ sensitivity of the present sensors. This artice was accidentally published twice. This is the second publication, please cite only the authoritative first one which is available at . An additional erratum is available at . An erratum to this article can be found at     

Analytical solution to a mode of mixed elastohydrodynamic lubrication with mixed contact regimes: Part II—Considering the contact adhering layer effect in the inlet zone

The present paper presents the researches succeeding the first part of the paper [Y.B. Zhang, Analytical Solution to A Mode of Mixed elastohydrodynamic lubrication with Mixed Contact Regimes: Part I—Without Consideration of Contact Adhering Layer in the Inlet Zone. Journal of Molecular Liquids, 2006, Vol.117, (10.1016/j.molliq.2006.04.006)], which analyzed one mode of mixed elastohydrodynamic lubrication with mixed contact regimes for the relatively heavy load and low rolling speed which make the conventional hydrodynamic lubrication occur in the inlet zone while make the physical adsorbed layer boundary lubrication occur in the Hertzian zone, based on the Newtonian fluid model. The present paper presents analysis to other two modes of mixed EHL with mixed contact regimes for relatively heavy loads, low rolling speeds and Newtonian fluids, where the conventional hydrodynamic lubrication, physical adsorbed layer boundary lubrication and oxidized chemical layer boundary lubrication can simultaneously occur in the inlet zone while the oxidized chemical layer boundary lubrication or the fresh metal-oxidized chemical boundary layer dry contact occur in the Hertzian zone, considering the contact adhering layer effect in the inlet zone. The present analysis is also extended to the first mode of mixed EHL with mixed contact regimes as analyzed in Part I [Y.B. Zhang, Analytical Solution to A Mode of Mixed elastohydrodynamic lubrication with Mixed Contact Regimes: Part I—Without Consideration of Contact Adhering Layer in the Inlet Zone. Journal of Molecular Liquids, 2006, Vol.117, (10.1016/j.molliq.2006.04.006)] when the contact adhering layer effect in the inlet zone is considered. Results of contact pressures, film thicknesses, load partitions in the contact and characteristic rolling speeds for approaching to zero averaged hydrodynamic film thickness in the Hertzian zone are obtained from this analysis respectively as functions of the contact adhering layer thickness in the inlet zone. The results show that the contact adhering layer effect in the inlet zone in the present EHL is reduced with the increase of load; At large loads, this effect may be negligible; At small loads, it may be very significant. The results also show that at low rolling speeds, when the contact adhering layer effect in the inlet zone is considered, the load-carrying capacity of the present EHL contact is increased especially for small loads. This means that at low rolling speeds the contact adhering layer effect in the inlet zone may reduce the elastohydrodynamic lubrication deviation from classical EHL theory predictions especially for small loads.