钨粉表面化学镀铜研究

为了提高钨粉制品的性能,采用正交实验方法,利用SEM、XRD、EDS等分析手段,系统研究了化学镀铜主要工艺参数对钨粉表面化学镀铜的影响规律。结果表明:在温度固定条件下,各因素对镀液稳定性影响的显著性顺序是:硫代硫酸钠加入量>pH值>χ(Tar2-/Cu2 )>甲醛加入量,而对镀速影响的显著性顺序是:χ(Tar2-/Cu2 )>pH值>甲醛加入量>硫代硫酸钠加入量;较佳的钨粉表面化学镀铜工艺为:五水硫酸铜8g/L;酒石酸钾钠28g/L;EDTA0.75g/L;NaOH8.5g/L;硫代硫酸钠10mg/L;甲醛7.5ml/L;pH=12;温度40℃。采用所推荐的工艺,成功的在钨粉上获得了化学镀铜层。     

一种基于蚁群算法的呼叫中心人力需求计算方法

针对呼叫中心人力需求优化这一离散约束问题,基于Dantzig提出的集合覆盖模型,建立了单技能呼叫中心的人力需求计算线性规划模型,并提出一种基于改进蚁群算法的求解方法.在该方法中,对算法的信息素更新规则进行了修改,并基于MATLAB编程针对实例进行仿真分析.选取统计学指标将算法的仿真结果与遗传算法进行对比,结果表明:基于蚁群算法的方法计算复杂度可行;能够节约人力,且话务员匹配度可满足实际运营需求;为智能算法在呼叫中心人力需求计算问题上的应用研究提供了一种新的解决思路.     

Ergonomic Analysis of Head‐Mounted Night Vision Goggle Systems in Simulated Ground Operations

This study compared the mounting time and strain on the head‐neck while using an old model (forehead and cheek supported) and a new model (head harness supported) of head‐mounted night vision goggle systems in the postures of standing, sitting, and lying prone. The results showed that effectively reducing the mounting time was attributed to the ease and less time required for length adjustments of the head harness in the new model. The novel device received higher positive subjective ratings for convenience and comfort while wearing than did the old model. Although the weight of the new model was decreased to 0.794 kg and the length was reduced to 0.155 m, the loads on the head‐neck complex remained high. These findings suggest that a rifle should be fitted with the night vision goggle or handheld model to decrease neck‐shoulder workload if the prone position is the most frequent and important posture for soldiers. © 2011 Wiley Periodicals, Inc.     

新形势下计算机教学的创新思维培养刍议

随着科学技术的进步与信息社会的到来,计算机成为社会中不可缺少的重要组成部分.新课改形势下,计算机教学如何与创新型人才培养结合.如何利用计算机教学的特点建构学生的创新思维是本文研究的重点.     

Four-scanning attack on hierarchical digital watermarking method for image tamper detection and recovery

In a recent paper presented by Lin et al., a block-based hierarchical watermarking algorithm for digital images is proposed. It adopts parity check and the intensity-relation check to conduct the experiment of image tamper detection. Their experimental results indicate that the precision of tamper detection and localization is 99.6% and 100% after level-2 and level-3 inspections, respectively. The proposed attacks demonstrate that this watermarking algorithm is fundamentally flawed in that the attacker can tamper a watermarked image easily without being detected. In this paper, a four-scanning attack aimed to Lin et al.'s watermarking method is presented to create tampered images. Furthermore, in case they use encryption to protect their 3-tuple-watermark, we proposed a blind attack to tamper watermarked images without being detected. Experimental results are given to support and enhance our conclusions, and demonstrate that our attacks are successful in tampering watermarked images.     

Replication of nanostructures on microstructures by intermediate film mold inserted hot embossing process

The present study proposes a simple method to replicate nano/micro combined multiscale structures using an intermediate film mold and anodic aluminum oxide (AAO) nanomold in hot embossing process. The proposed method is simply to add an intermediate film mold with microscale thru-hole patterns to the ordinary mold system, on which nanostructures are patterned, in the hot embossing process. The intermediate film mold is inserted between polymer substrate and AAO nanomold. During the hot embossing process, the polymer first fills microscale thru-hole patterns in the intermediate film mold and subsequently fills nanopores in AAO nanomold, resulting in the nano/micro combined structures. The intermediate film molds, which have microscale thru-hole patterns were fabricated by micro-milling, laser ablation, etching methods and/or LIGA process. The nano/micro combined structures were successfully replicated by the proposed method.     

Collapse-free thermal bonding technique for large area microchambers in plastic lab-on-a-chip applications

Bonding is an essential step to form microchannels or microchambers in lab-on-a-chip applications. In this paper, we present a novel plastic thermal bonding technique to seal and form large area microchambers (planar characteristic width and length on the order of 1 mm and characteristic thickness on the order of 10–100 μm) without collapse by introducing a holed pressure equalizing plate (HPEP) that includes holes of the same size and shape as the microchambers. To demonstrate the proposed technique, two types of large area microchambers [(1) 20 × 10 mm and 40 μm thick and (2) 12 × 2.5 mm and 120 μm thick] with microchannels were designed and replicated on plastic substrates by means of hot embossing and injection molding processes with prepared two nickel mold inserts. The replicated large area microchambers as well as the microchannels in the plastic lab-on-a-chip were successfully sealed (i.e., no leakage) and formed without any collapse by the proposed thermal bonding technique with the help of the HPEP.     

A neural network-based approach for dynamic quality prediction in a plastic injection molding process

This paper presents an innovative neural network-based quality prediction system for a plastic injection molding process. A self-organizing map plus a back-propagation neural network (SOM-BPNN) model is proposed for creating a dynamic quality predictor. Three SOM-based dynamic extraction parameters with six manufacturing process parameters and one level of product quality were dedicated to training and testing the proposed system. In addition, Taguchi’s parameter design method was also applied to enhance the neural network performance. For comparison, an additional back-propagation neural network (BPNN) model was constructed for which six process parameters were used for training and testing. The training and testing data for the two models respectively consisted of 120 and 40 samples. Experimental results showed that such a SOM-BPNN-based model can accurately predict the product quality (weight) and can likely be used for various practical applications.     

基于SOPC的通用图像处理系统设计

本文介绍了基于SOPC的通用嵌入式图像处理系统的实现方法.其中叙述了SOPC及Nios Ⅱ嵌入式处理器的特点和使用,分别具体说明了系统的硬件结构设计和图像处理算法的流程及软件实现,采用此系统可以大大简化图像处理系统的硬件和软件设计,优化系统设计.