考虑售后服务和配送成本的选址问题系统的建模仿真

加强售后服务与降低流通费用是现代企业经营管理的两大目标。采用分步寻优法建立了服务配送系统选址数学模型，给出了考虑售后服务的配送系统选址问题程序设计算法描述。仿真结果验证了系统模型与算法的有效性。     

非均相乙烯聚合催化剂载体研究新进展

文章介绍了近年来聚乙烯催化剂载体的研究情况,着重介绍了无机载体,粘土载体,分子筛载体,高分子载体的研究现状。无机载体主要集中于提高载体酸度,及其向纳米载体方向发展,粘土作为聚乙烯催化剂载体可以有效的改性聚合物的力学性能,可以制备高性能复合材料,MCM-41,SBA-15,ZSM-5等分子筛载体展示出了比SiO2作为载体更好的催化活性,增加载体的酸性会明显的提高活性,有序排列的大孔道结构将会更有利于活性中心的负载和乙烯的聚合反应。有机化合物类高分子载体由于不需要对载体本身进行预处理也受到越来越多的重视。     

Refining operation guidelines with model-checking-aided FRAM to improve manufacturing processes: a case study for aeroengine blade forging

With the aid of the Finite State Machine (FSM) and formal verification, a framework of updated Functional Resonance Analysis Method (FRAM) is proposed to refine operation guidelines as such and hence improves manufacturing processes by reducing risks of unqualified products during manufacturing operations. Firstly, the FRAM is used to model a manufacturing process in terms of the corresponding guideline, taking into account all the basic activities each with their performance variability and the potential couplings among the activities. Secondly, based on the FRAM model further interpreted with FSM, the model checker SPIN is adopted to achieve the exhaustive search (in the sense of execution) for the paths leading to manufacturing risks, which supports to illustrate how the performance variability in the activities couples and finally causes violation of quality control requirements. Finally, possible inadequacies and deficiencies of the operations are identified and measures for refining the guideline are developed to minimize the risks due to the inherent issues of specification in the guideline. In a case study, the proposed framework is applied to a typical manufacturing process prone to risks, i.e., forging of aeroengine titanium alloy blades, and the analysis results indicate practicality of the framework, as well as effectiveness of the guideline refinements.     

Experimental Approach and Evaluation on Dynamic Reliability of PBGA Assembly

The aim of this paper is to provide a systematic method to perform experimental test and theoretical evaluation on fatigue characteristics of plastic-ball-grid-array (PBGA) assembly under random vibration. A specified PBGA assembly which contains different structural and material parameters was manufactured. The fatigue characteristics of PBGA assembly under random vibration were tested. Manson-Coffin empirically derived formula and rain-flow algorithm were used to achieve the fatigue life of solder joints. In the meantime, the failure curve (reliability-cycle number curve) can be obtained by using Weibull distribution method when PBGA assembly is on different working situation. Finally, life prediction of corner solder balls was deduced based on three-band technology and cumulative damage index. Test results lay a basis for high-reliability design of PBGA assembly for engineering application.     

碳纤维－水泥基复合材料应力传感器的研究

本文探讨了碳纤维－水泥基复合材料应力传感器（ＣＦＣＳ）的制备，对其性能与碳纤维含量的关系进行了实验研究，并对实验结果作了理论上的探讨与分析。     

Raman—Nath条件下吸收介质中的四波混频理论

本文在Raman-Nath条件下理论研究了吸收介质中的四波混频,分析了反射率与吸收系数及相互作用长度的关系。     

GSA-based maximum likelihood estimation for threshold vector error correction model

The log-likelihood function of threshold vector error correction models is neither differentiable, nor smooth with respect to some parameters. Therefore, it is very difficult to implement maximum likelihood estimation (MLE) of the model. A new estimation method, which is based on a hybrid algorithm and MLE, is proposed to resolve this problem. The hybrid algorithm, referred to as genetic-simulated annealing, not only inherits aspects of genetic-algorithms (GAs), but also avoids premature convergence by incorporating elements of simulated annealing (SA). Simulation experiments demonstrate that the proposed method allows to estimate the parameters of larger cointegrating systems. Additionally, numerical results show that the hybrid algorithm does a better job than either SA or GA alone.     

液压装配图自动消隐功能的实现

本语文介绍液压二维装配图自动消隐程序ＨＴＲＩＭ的功能、原理有特点。根据国产液压件的外型特征。采用ＡｕｔｏＬＩＳＰ、ＡＤＳ程序设计实现液科绘制的自动消隐,实际上是ＡｕｔｏＣＡＤ的一种独特的二维图形消隐算法。     

Multivariate calibration of on-line enrichment near-infrared (NIR) spectra and determination of trace lead in water

An on-line enrichment near-infrared spectroscopy (NIRS) technique was developed in order to improve the sensitivity for the determination of trace heavy metal lead. Trace Pb²⁺ was enriched by chelating resin with on-line enrichment equipment and then the enriched lead on the resin was directly determined by near-infrared diffuse reflectance spectroscopy without elution procedure for simplicity of measurements. Partial least squares (PLS) regression was used to build models between the corrected spectra and concentrations of Pb²⁺, and segmental cross-validation was used to search for a reasonable number of PLS factors. The results showed that NIR spectra and concentrations of Pb²⁺ had a good linear relationship with the maximum of correlation coefficient of 0.9228 in the 1006–1383 nm region. The minimum RMSEP was 0.4777 mg L^− 1 when the latent variable number was 5 by using the region of 1006–1383 nm. The limit of detection (LOD) of lead was 0.2384 mg L^− 1 in this case. This study demonstrates that the prediction of trace heavy metal lead concentrations by NIRS is feasible with enrichment technique.     

Staircase Control of Hybrid Cascaded Multi-level Inverter

A cascaded multi-level inverter consists of H-bridge modules that can generally be divided into one with the same DC bus voltage and another with different DC bus voltages. By using the same power device as a standard 7-level 3H-bridge converter, the proposed converter operates with 15-level resolution with separate DC voltage sources of voltage ratio 4:2:1. The analysis of this hybrid cascaded converter with staircase control shows that this proposal can be applied in many power conversion applications, such as flexible alternative current transmission systems, uninterruptible power supply, and electric power conversion, transmission, and storage of renewable energy sources. Simulation results are presented with the proposed 15-level cascaded H-bridge inverter for a low distortion, near-sinusoidal stepped-voltage output, and a laboratory prototype of a 15-level insulated gate bipolar transistor-based cascaded H-bridge inverter is designed and implemented on a digital signal processor. The total harmonic distortion is proved less than 5%.