基于知识的汽车发动机润滑油状态监测系统的研究

本文提出了一种基于知识的汽车发动机润滑油状态监测系统模型，并简要介绍了该系统的基本原理与构成，由于其中心处理部分基于一个知识系统上，因此具有比一般的润滑油状态监测更强的功能，能实现对在用润滑油衰变及发动机磨损状态的自动推一和判断。在具体分析的基础上，说明了该系统实现的可行性。     

Immune clonal selection algorithm for capacitated arc routing problem

In existing metaheuristics for solving the capacitated arc routing problem, traversal local search operators are often used to explore neighbors of the current solutions. This mechanism is beneficial for finding high-quality solutions; however, it entails a large number of function evaluations, causing high computational complexity. Hence, there is a need to further enhance the efficiency of such algorithms. This paper proposes a high-efficiency immune clonal selection algorithm for capacitated arc routing instances within a limited number of function evaluations. First, an improved constructive heuristic is used to initialize the antibody population. The initial antibodies generated by this heuristic help accelerate the algorithm’s convergence. Second, we show how an immune clonal selection algorithm can select in favor of these high-quality antibodies. By adopting a variety of different strategies for different clones of the same antibody, it not only promotes cooperation and information exchanging among antibodies, but also increases diversity and speeds up convergence. Third, two different antibody repair operations are proposed for repairing various kinds of infeasible solutions. These operations cause infeasible solutions to move towards global optima. Experimental studies demonstrate improved performance over state-of-art algorithms, especially on medium-scale instances.     

基于支持向量机的大跨度拱桥损伤识别方法研究

作为一种新兴的机器学习算法,支持向量机在损伤识别中已显示出其回归能力的优越性。将模态曲率改变率作为损伤识别特征参数,提出了基于支持向量机的大跨度拱桥损伤识别方法。首先应用模态曲率改变率进行损伤定位识别,然后重新构造训练样本,利用最小二乘支持向量机方法进行大跨度拱桥的损伤程度识别,该方法在较少的样本条件下,取得了非常接近目标值的识别效果。通过与RBF神经网络的训练结果进行对比,验证了该方法的精确性。     

Study on quality of resistance spot welded aluminum alloys under various electrode pressures

The electrode force is one of the main parameters in resistance spot welding (RSW). It is very important to guarantee the quality of aluminum alloys and determine whether the electrode pressure is stable or adjustable in the welding process. With the drive set of a servo-motor, we conduct the RSW tests and tensile shear tests on the 5052 aluminum alloy sheets. Results of these tests show that all variable pressure curves are suitable for spot welding, and all have their own rules in affecting the tensile strength of the spot welded joints.     

Preparation and Magnetic Properties of MnFe2O4 Octahedral Microcrystals

MnFe₂O₄ octahedra have been prepared by reaction of Mn²⁺ ions and Fe³⁺ in alkaline condition via heat treatment of the coprecipitation product. The as-prepared powders were characterized in detail by conventional techniques such as powder x-ray diffraction; field emission electron microscopy and transmission electron microscopy. Vibrating sample magnetometer was used to determine the magnetic properties at room temperature. The results show that the MnFe₂O₄ octahedra were single crystals with cubic jacobsite structure and a size distribution from 0.8 to 1.0 μm. The octahedra obtained at 1100 and 1200 °C exhibited a ferromagnetic behavior with the coercive force (H _c) value of 49.03 and 39.23 Oe, saturation magnetization (M _s) value of 42.93 and 47.98 emu/g and remanent magnetization (M _r) value of 2.16 and 2.55 emu/g, respectively. It is indicated that the heat treatment temperature has a significant effect on the formation of the jacobsite structure. Furthermore, a possible mechanism was also proposed to account for the growth of these products.     

Improved hydrogen desorption properties of ammonia borane by Ni-modified metal-organic frameworks

Ammonia borane (AB) has attracted intensive study because of its low molecular weight and abnormally high gravimetric hydrogen capacity. However, the slow kinetics, irreversibility, and formation of volatile materials (borazine and ammonia) of AB limit its practical application. In this paper, new strategies by doping AB in metal-organic framework MIL-101 (denoted as AB/MIL-101) or in Ni modified MIL-101 (denoted as AB/Ni@MIL-101) are developed for hydrogen storage. In AB/MIL-101 samples, dehydrogenation did not present any induction period and undesirable by-product borazine, and decomposition thermodynamics and kinetics are improved. For AB/Ni@MIL-101, the peak temperature of AB dehydrogenation was shifted to 75 °C, which is the first report of such a big decrease (40 °C) in the decomposition temperature of AB. Furthermore, borazine and ammonia emissions that are harmful for proton exchange membrane fuel cells, were not detected. The interaction between AB and MIL-101 is discussed based on both theoretical calculations and experiments. Results show that Cr-N and B-O bonds have generated in AB/MIL-101 nanocomposites, and the decomposition mechanism of AB has changed.     

挤占来进料加工市场提高国产树脂占有率

分析了来进料加工市场的特点 ,对国产树脂进入来进料加工市场所面临的问题作了一定深度的探讨 ,并提出了一些建议     

关于广泛开展高性能计算课程的教学探讨

高性能计算的广泛应用,说明开展高性能计算教学的必要性.根据开展高性能计算课程教学的可行性,提出了课程的基本教学方法:用PC机组建计算网络以及基于移植性较强并提供免费技术支持的MPI并行平台.在Windows操作系统上,虚拟Unix系统以模拟高性能程序设计.条件准许时,把设计成功的高性能计算程序推广到高性能计算系统上运行.在教学实践过程中证明,采用这种教学方法开展高性能计算的教学工作,对提高学生的自身能力,取得了良好的教学效果.     

Numerical Analysis of the Catalytic Combustion of Premixed Methane/Air Mixtures in Microtubes

The combustion characteristics and extinction limits for the catalytic combustion of a methane/air mixture in a microtube are investigated computationally using the commercial CFD code FLUENT coupled to an external subroutine DETCHEM. The effects of the microtube dimensions, conductivities of wall materials, external heat losses and flow velocity on the combustion stability, are also studied. The numerical model is set as either adiabatic or non‐adiabatic with a fixed exterior heat transfer coefficient. Numerical results indicate that thermal conductivity and wall thickness are vital to preheat the methane/air mixture through the conducting wall. Two types of extinction occur, i.e., thermal quenching and blow out. These extinction limits are characterized by wall surface temperature in the microtube and the ratio of Pt(s)/O(s).     

Multiobjective optimization using an immunodominance and clonal selection inspired algorithm

Based on the mechanisms of immunodominance and clonal selection theory, we propose a new multiobjective optimization algorithm, immune dominance clonal multiobjective algorithm （IDCMA）. IDCMA is unique in that its fitness values of current dominated individuals are assigned as the values of a custom distance measure, termed as Ab-Ab affinity, between the dominated individuals and one of the nondominated individuals found so far. According to the values of Ab-Ab affinity, all dominated individuals （antibodies） are divided into two kinds, subdominant antibodies and cryptic antibodies. Moreover, local search only applies to the subdominant antibodies, while the cryptic antibodies are redundant and have no function during local search, but they can become subdominant （active） antibodies during the subsequent evolution. Furthermore, a new immune operation, clonal proliferation is provided to enhance local search. Using the clonal proliferation operation, IDCMA reproduces individuals and selects their improved maturated progenies after local search, so single individuals can exploit their surrounding space effectively and the newcomers yield a broader exploration of the search space. The performance comparison of IDCMA with MISA, NSGA-Ⅱ, SPEA, PAES, NSGA, VEGA, NPGA, and HLGA in solving six well-known multiobjective function optimization problems and nine multiobjective 0/1 knapsack problems shows that IDCMA has a good performance in converging to approximate Pareto-optimal fronts with a good distribution.