Improved Tribocorrosion Properties of Ti6Al4V Alloy by Anodic Plasma Electrolytic Oxidation

Ti6Al4V alloy has good corrosion resistance due to the formation of the passive oxide films on the surface of Ti6Al4V alloy. However, Ti6Al4V alloy has poor tribocorrosion resistance in the seawater environment. Herein the present work, plasma electrolytic oxidation (PEO) with the electrolyte of glycerol and sodium borate is used to generate PEO coatings on the surface of Ti6Al4V alloy to improve its tribocorrosion properties. The microstructure and tribocorrosion properties of PEO coatings are investigated by using scanning electron microscopy, X-ray diffraction, and tribometer, respectively. The growth kinetics and the tribocorrosion mechanisms of PEO coatings are discussed in detail. It is shown in the results that PEO coatings deposited on the surface of Ti6Al4V alloy are composed of rutile and anatase phases. The surface hardness and thickness of PEO coatings are enhanced with the increase of the voltage and time. The wear rate of Ti6Al4V alloy with PEO coatings is significantly reduced in artificial seawater.     

大庆HDPE装置改扩建可行性分析

大庆石化总厂规划在“九五”期间将30万t/a乙烯装置扩建到48万t/a,HDPE装置是主要的乙烯使用装置。根据该装置几年来的生产实践及与日本三井油化同类装置生产情况的对比,并经过对主要操作单元的详细计算,对该装置设计能力由14万t/a扩建到24万t/a进行了可行性分析,提出了通过对部分设备进行改造后,产量提高10万t/a是可行的。     

Retardation of human drug-resistant HL-60 cell in G1 phase and induction of sensitive cell to apoptosis by cyclosporine A

To further study the relationship between resistance to apoptosis and drug resistance in harringtonine-resistant HL-60 cells (HR20), cyclosporine A (CsA) 20, 10 micrograms.ml-1 was shown to induce the sensitive HL-60 cells to apoptosis, showing a typical DNA "ladder" band. But the same concentrations of CsA retarded the HR20 cells in G1 phase and could not induce the cells to apoptosis. The cellular daunorubicin accumulation increased when HR20 cells were treated with low concentration of CsA and the reversal of drug resistance by CsA was unrelated to the retardation of cell cycle progression. High phosphorylation of about 50 kDa protein occured when HR20 cells were treated with CsA 10 micrograms.ml-1. The results domonstrate that cyclosporine A retarded the harringtonine-resistant HL-60 cells in G1 phase but induced HL-60 cells to apoptosis, and the retardation was unrelated to drug resistance.     

An immune-inspired approach to qualitative system identification of biological pathways

In this paper, a special-purpose qualitative model learning (QML) system using an immune-inspired algorithm is proposed to qualitatively reconstruct biological pathways. We choose a real-world application, the detoxification pathway of Methylglyoxal (MG), as a case study. First a converter is implemented to convert possible pathways to qualitative models. Then a general learning strategy is presented. To improve the scalability of the proposed QML system and make it adapt to future more complicated pathways, a modified clonal selection algorithm (CLONALG) is employed as the search strategy. The performance of this immune-inspired approach is compared with those of exhaustive search and two backtracking algorithms. The experimental results indicate that this immune-inspired approach can significantly improve the search efficiency when dealing with some complicated pathways with large-scale search spaces.     

基于静态路由的ISP负载均衡解决方案

传统的ISP负载均衡方法主要有2种,一是使用开启BGP协议的高端防火墙;二是使用专业负载均衡设备.本论文建立了1套新型的基于静态路由的ISP负载均衡解决方案.本文首先通过Whois协议获得ISP的AS号码,在公网BGP路由器数据库中根据这个AS号码查询属于不同ISP的全部BGP路由条目;之后将不同ISP(例如中国电信和中国联通)的路由条目导入园区网边界防火墙,使得用户访问实现负载分担和路由备份.本方案适用于大中型企业和大型居民小区园区网,相比传统的负载均衡方法,本方案能够节省大量设备投资.     

基于DDS的低通滤波器设计与仿真

分析了几种经典滤波器特性,重点研究了DDS系统中低通滤波器的设计方法。根据DDS的结构特点和输出杂散频谱特性,结合滤波器技术指标使用了归一化法完成了一个九阶椭圆函数低通滤波器的设计,使其通带截至频率为120MHz、通带内最大衰减为0.2dB、在135MHz处阻带内最小衰减为66dB。通过Multisim10对其进行仿真后可以得出,使用此种方法设计的低通滤波器过渡带陡峭、幅频特性仿真良好,并且能够很好地满足预期的技术指标。     

A guided local search procedure for the multi-compartment capacitated arc routing problem

In this paper, we introduce and study the multi-compartment capacitated arc routing problem—an extension of the classical capacitated arc routing problem, but where the required edges have a demand for different products, and multi-compartment vehicles are available to co-distribute these commodities. We present a local search algorithm that exploits well-known moves (2-opt, re-insert, relocate, exchange and cross). We take advantage of speed up tricks such as marking and neighbour lists, and we combine the procedure with the guided local search meta-heuristic in order to reach high quality solutions. We report on results from extensive computational experiments. Our aim is to reveal in what situations co-distribution by partitioned vehicles saves in routing costs as compared with separate distribution with un-partitioned trucks. We explore sensitivities in key problem characteristics including, the number of commodities, the vehicle capacity, the location of the depot and required edges, the density of required edges, and the demand per commodity for the required edges.     

基于混合蛙跳算法改进的OTSU遥感图像分割方法

阈值的快速选取和噪声处理对图像分割起着至关重要的作用。针对遥感图像分割过程中阈值快速选取和噪声处理的问题,首次提出一种基于混合蛙跳算法优化改进的OTSU遥感图像快速分割算法。该算法首先对图像进行处理,引入一个邻域的空间和灰度相似测量因子来进行抗噪并且保护图像细节。再以最大类间方差作为混合蛙跳算法适应度函数,通过混合蛙跳算法的局部搜索和全局信息交换来快速确定图像分割的全局最佳阈值。实验结果表明,与传统OTSU图像分割算法及基本遗传算法改进的二维OTSU图像分割算法相比,该算法能更有效地去除噪声的干扰,算法运算效率更高。     

改进的FCM与局部信息相结合的图像分割

传统的EM算法和FCM算法分割精度低,时间消耗大。为解决以上不足,提出了一种基于EM、FCM和KCN三种算法相结合的全新的图像分割算法。该算法有较好的分割精度。考虑到图像会受到噪声的干扰,在改进算法的基础上又引入图像的局部信息。首先利用图像的局部信息重塑图像的灰度直方图,增强了像素的类间散布性和类内紧凑性,然后让改进的算法在重塑图像上执行。实验结果表明,该算法具有很好的分割效果和较强的抗噪性能。     

大功率天然气发动机怠速控制策略研究

为提高大功率天然气发动机怠速时的稳态和动态效果,以V模式为研究手段,基于一款六缸天然气多点电喷发动机,实现了发动机怠速控制策。首先针对不同的怠速工况设计了不同的目标怠速转速值的计算,并根据发动机特性确定了PI控制模式。利用目标怠速转速和瞬时转速的差值确定不同PI控制参数,通过PI控制调节电子节气门的开度,从而实现对发动机怠速转速的控制。然后根据实际发动机参数搭建了发动机MATLAB/SIMULINK仿真模型,用于对怠速控制策略进行软件在环仿真测试以及PI控制参数预标定。最后在天然气发动机试验台架上对控制策略进行了进一步的试验和标定。试验结果表明：该怠速控制策略,可让发动机转速响应时间控制在1秒左右,转速稳定时间在2秒左右,发动机转速稳态误差控制在±5rpm范围之内,实现了对怠速的良好稳定控制。