A Truncated Sum of Processing‐Times–Based Learning Model for a Two‐Machine Flowshop Scheduling Problem

Scheduling with learning effects has gained increasing attention in recent years. A well‐known learning model is called “sum‐of‐processing‐times‐based learning” in which the actual processing time of a job is a nonincreasing function of the jobs already processed. However, the actual processing time of a given job drops to zero precipitously when the normal job processing times are large. Moreover, the concept of learning process is relatively unexplored in a flowshop environment. Motivated by these observations, this article addresses a two‐machine flowshop problem with a truncated learning effect. The objective is to find an optimal schedule to minimize the total completion time. First, a branch‐and‐bound algorithm incorporating with a dominance property and four lower bounds is developed to derive the optimal solution. Then three simulated annealing algorithms are also proposed for near‐optimal solution. The experimental results indicated that the branch‐and‐bound algorithm can solve instances up to 18 jobs, and the proposed simulated annealing algorithm performs well in item of CPU time and error percentage. © 2011 Wiley Periodicals, Inc.     

A simple planar monopole UWB slot antenna with dual independently and reconfigurable band‐notched characteristics

An extremely simple and compact planar monopole ultrawideband (UWB) slot antenna with dual band‐notched characteristics is proposed. The antenna is composed of a circular radiation patch, a microstrip‐fed line, and a partial ground. By etching an arc‐shaped slot on the radiation patch and a C‐like slot on the feed line, dual notched frequency bands at 3.3–3.7 GHz for WiMAX and 5.15–5.825 GHz for WLAN are achieved. And, the two notched bands can be adjusted independently by varying the length of the slots. Moreover, the band‐notched characteristics can be reconfigurable by shorting the corresponding slots. So, the antenna is capable of operating in one of multiple modes which makes it an excellent candidate for UWB applications. Meanwhile, experimental results indicate that the antenna has an available impendence bandwidth from 2.9 to 11 GHz which covers the UWB frequency band, and nearly omnidirectional patterns, stable gains, small group delay in operating band except rejected bands. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:706–712, 2014.     

木塑复合材料制品一步法挤出成型技术的研究

介绍了木塑复合材料制品一步法挤出成型中常见的5种挤出设备,提出了选择这些设备时需要考虑的一些因素,分析了木塑复合制品挤出成型技术中温度、压力、喂料和排气等问题产生的原因。并结合实验和理论,从螺杆、机筒、机头设计和加料器选择等方面提出了解决这些问题的措施。     

用于清除胆红素的壳聚糖膜的吸附性能研究

采用溶出法，以硅胶粒子为成孔剂制备了壳聚糖微孔膜，并用环氧氯丙烷对其进行了交联处理。以含胆红素的磷酸盐缓冲液作为模拟血浆，通过静态和动态实验测定了胆红素在膜上的吸附性能，考察了膜交联处理、温度、离子强度、胆红素初始浓度、白蛋白等因素对吸附的影响。结果表明：胆红素在膜上的吸附平衡符合Freundlich方程；在较高的温度、较低的离子强度下胆红素的去除效果较好；未交联处理的膜对胆红素的去除率高达94％，经交联处理后去除率为84．6％；加入白蛋白后，去除率下降。与壳聚糖树脂吸附胆红素的方法相比，采用壳聚糖微孔膜法达到吸附平衡的时间短。     

真空溅射加工用铁氧体粘接件的制备

主要介绍了高温粘接技术在铁氧体环真空溅射加工中的应用,通过对耐高温胶粘剂的优选及工艺实现途径的探索,较好地将多个铁氧体环粘接为一体。并在其外表面溅射镀铜,粘接强度及粘接精度在高温环境下均达到设计要求。     

UHMWPE共混改性HDPE薄膜性能的研究

采用中等摩尔质量聚乙烯（MMWPE）首先对超高摩尔质量聚乙烯（UHMWPE）进行改性，然后通过两步共混法制备了HDPE／UHMWPE共混吹塑薄膜，研究了共混物的力学、流变性能以及MMWPE对UHMWPE力学和流变性能的影响。实验结果表明，当改性UHMWPE中的MMWPE的质量分数为40％时，改性UHMWPE的力学性能下降不大，而流变性能大大改善。两步法制得的HDPE／UHMWPE薄膜表面的晶点明显减少，比一步法得到的薄膜的拉伸强度和撕裂强度分别提高了20％和12％，比纯HDPE的分别提高45％和21％。     

炭/炭复合材料MoSi2/SiC抗氧化涂层的研究

采用包埋法制备C／C复合材料抗氧化MoSi2／SiC梯度涂层，同时对抗氧化涂层的形成、组织结构以及抗氧化性能与渗料的关系和抗氧化机理进行了研究。结果表明：采用包埋法制备的C／C复合材料抗氧化MoSi2／SiC梯度涂层致密，但有少量裂纹，涂层有良好的抗氧化效果。当Si与SiC保持一定的比例时，渗料中MoSi2的含量为50％时，涂层具有最好的抗氧化效果；当MoSi2与SiC保持一定的比例时，渗料中Si的含量为20％时，涂层具有最好的抗氧化效果。     

近红外光谱技术在酚醛预浸布中的应用

为了对预浸布进行快速检测,采用近红外漫反射的方法对高硅氧/酚醛预浸布,碳/酚醛预浸布中的树脂含量、可溶树脂含量和挥发份含量进行在线监测,三项指标同时显示.通过偏最小二乘方法分别建立标准模型,用模型的评价指标评价,分析未知样品.用近红外方法在1 min之内同时分析出结果,没有破坏性.用近红外的测定结果和标准方法的测定结果相比,两者不存在显著性差异.近红外光谱的方法可以应用在酚醛预浸料生产线上.     

电力工程自动化系统故障分析的方法

由于电力工程自动化系统的操作程序不断复杂化,故障的出现频率也随之增加。因此,必须建立完善的故障分析和解决方案,方能保证电力工程的正常、顺利推进。在此基础上,就电力工程自动化系统故障分析方法进行分析、探讨。     

机场综合监视与引导系统运动模块设计及实现

随着民航运输业的迅猛发展,机场起落流量逐年增大,机场内各种车辆的运行给机场场面管理带来巨大的压力。对于目前民航这种发展形势,近年来提出了地面滑行引导与控制系统概念,该概念旨在满足繁忙机场的滑行引导与控制需求。结合传统地面滑行引导与控制系统概念设计了滑行引导运动模块,并通过C＋＋实现。