High immunity wafer-level measurement of MHz current

Wafer-level characterization of functional prototypes of solid state current sensors is usually the first step in the development stage, therefore a dedicated wafer-level measurement systems are required. Especially for MHz characterization, where electromagnetic interference issues became strongly relevant. Thus, for frequencies above 1 MHz, a sophisticated measurement techniques are needed, because parasitic couplings can significantly affect sensor response and other signal processing stages, causing errors or malfunction of the whole system. We propose technique for high immunity MHz current measurement by solid state sensor in wafer-level configuration. The system is especially well-suited for MHz characterization, where electromagnetic interference issues become highly relevant. We showed that balanced transmission provides possibility to reduce interference in the sensor biasing circuit of about 60 dB compared to single-ended method. The effectiveness of the proposed technique was tested in monitoring MHz current in the external line by single magnetoresistive sensors on wafer level.     

Current transients of passive iron observed during micro-indentation in pH 8.4 borate buffer solution

Micro-indentation test of passive iron electrode in deaerated pH 8.4 borate buffer solution was carried out to investigate the rupture and repair of passive film. During driving a conical diamond micro-indenter with a load of 0.1 N order downward to the electrode and driving upward from the electrode, a couple of anodic current peaks were observed. The first current peak spiked during loading was responsible for partial exposure of iron substrate to the solution due to rupture of the passive film when the indenter tip contacted. The second peak emerged during unloading when elastic deformation recovered, which was ascribed to repair at the ruptured sites. The second peak current was larger than the first one. Both peaks were sensitively influenced by electrode potential or concentration of sulfate ions containing in solution. The model for a series of rupture and repair processes of the passive film by micro-indentation was proposed to discuss the current transients.     

我国钢管行业未来发展趋势分析

简要介绍了我国钢管行业的现状,指出了我国钢管行业在快速发展的同时所存在的一些主要问题。结合钢管行业的发展规律、现状以及发展要求,分析了我国钢管行业未来一段时期的发展趋势：建设创新型钢管企业,组建大型钢管企业集团,适度控制钢管产能,转变经济增长方式,不断提高钢管装备国产化率．加大能源综合利用力度,关注原料供应和钢管精整,适应钢管市场变化,加速钢管标准与国际接轨,重视钢管产品的深加工。     

稠油蒸汽吞吐后期增产技术现状与前景

目前,国内外许多油藏已处于蒸汽吞吐的后期。此时的油藏油气比低、含水量高、地层压力低、井况差、周期注气量大、操作成本高,产油更加困难。改善蒸汽吞吐后期的采油技术,可以最大限度的提高油藏的采收率。如今,应用于蒸汽吞吐后期增产的方法有:应用助剂改善吞吐效果、间歇注汽技术、"一注多采"技术、多井整体吞吐技术、注采参数优化技术、侧钻水平井技术、蒸汽驱技术、蒸汽辅助重力泄油技术和火烧油层技术等。然而,现在我国还在尝试发展一些新的技术,如水平压裂辅助蒸汽驱和多井组整体优化蒸汽驱等等。这使得蒸汽吞吐后期的增产技术拥有更为广阔的前景。     

轴向混合磁悬浮轴承磁场与控制研究

采用有限元法对轴向混合磁悬浮轴承的磁场进行分析,应用三角剖分单元建立了磁悬浮轴承模型,在泛函分析基础上归纳出了磁位势的计算方程。根据所建模型,分析了永磁偏置磁场的磁通与磁感应强度分布特点、研究了电流控制磁场独自存在时的磁通分布和磁感应强度分布规律,描述了磁场力与控制电流的关系曲线。进而深入解析了永磁偏置磁场和电流控制磁场叠加条件下的磁通与磁感应强度分布特点,并得出磁场力与控制电流的关系。     

MAS小波的钢板表面缺陷边缘检测的研究

针对钢板表面缺陷与背景的对比度差、边缘复杂、采光不均、噪声较大等特点,应用一种基于MAS小波变换进行钢板表面缺陷边缘检测。该方法由Lipschitz指数阐明了图像的边缘几何结构,通过分析图像中不同类型的奇异点,并结合尺度独立算法区分了目标图像中不同类型的边缘,有效的提取了钢板表面缺陷图像的边缘。实验结果表明,基于MAS小波算法可以有效提取图像中阶梯型边界,检测到的缺陷边缘轮廓较为清晰,且去噪能力较强,检测效果优于传统的同类方法。     

一种桥式起重机金属结构失效检测系统设计

通过分析桥式起重机金属结构失效形式和主要失效部位,设计了一种桥式起重机金属结构失效检测系统,该系统可在起重机工作状态下得到其金属结构的应变情况,为桥式起重机的维护和故障诊断提供依据。     

基于 PLC 的吸塑机电气控制系统开发

针对老式吸塑机在电气控制方面存在的缺陷,提出了用PLC来改造吸塑机的电气控制系统,并主要介绍了PLC控制系统的设计方法。通过对吸塑工艺的分析,结合PLC应用,完成了全自动吸塑机研制。与以往手动或半自动吸塑机相比较,提高了吸塑工作效率和产品质量,增加了系统柔性。     

GC-MS/MS方法测定大米中农药残留杀虫环

目前测定大米中杀虫环的农药残留多采用气相色谱方法,样品前处理时试剂需要提纯,既危险又繁琐,目标峰还存在干扰,影响定性;采用液相色谱和液质联用的方法处理样品需使用固相萃取柱,增加了检测成本,也比较费时间,液质联用方法虽然定性比较准确,但其检出限比较高。本文采用溶剂萃取方法处理样品,气质质联用仪测定,样品处理简单,耗材成本低。本方法对仪器条件进行了优化,具有较好的重复性和较低的检出限。测定重复性的标准偏差(RSD)达到4.1%,检出限达到0.8μg/kg,由于本方法较低的检出限,对研究大米中农残杀虫环的降解过程将提供有力的检测手段。     

基于多种检测像素预测方式的LSB图像信息隐藏检测

本文突破了传统LSB隐写分析算法只针对图片整体特征提取、监测手段不够精细的缺陷,提出了针对每一像素点的针对性判断。算法主要利用图像函数估计、噪声判断、像素值估计等方法,通过预测每一像素是否被改动,来判断整张图片的嵌入情况,从而实现小嵌入率隐写分析与嵌入点大致估计的目标。算法的检测率较以往算法有明显提高,对低嵌入率（1%以内）的LSB嵌入检测效果尤为有效。同时对高嵌入率的嵌入,算法保证了99.9%以上的准确率。