新型纳米管针尖探针将提供细胞研究新手段

Drexel大学工程学院的科学家最近成功发明了一种有碳纳米管（CNT）尖端的吸液管，这对于细胞生物学领域的DNA测序以及细胞器药物运输非常重要。     

电阻阵列式舰船红外靶标温控方法研究

本论文结合实际打靶需要,根据目标与背景的红外辐射特性的基本原理设计了一种电阻阵列式舰船红外模拟靶标系统。通过本论文,对电阻阵列式舰船红外靶标的工作原理,基本组成,以及温度模型建立方法和控制方法作了介绍。     

新型系列二极管阵列检测器性能评价

对 3种不同阵列数的新型二极管阵列检测器 -DAD2 30 (2 5 6阵列 )、DAD2 30 (5 12阵列 )、DAD2 30 (10 2 4阵列 )的基线噪声、漂移、线性范围、波长准确性等性能进行系统考察 ,重点考察阵列分辨率差异对光谱分辨率的影响。通过测试得到 3种检测器性能指标分别为 :基线噪声在 1. 2× 10. 5～ 2 . 1× 10 . 5AU之间 ,基线漂移平均为 6× 10 . 4 AU ,在 2 5 .4nm时对萘的最小检测量以 5 12阵列最好 ,可达 5 . 11× 10 . 10 g ,采用两种方法测试的线性范围都大于 1 0× 10. 4 ,波长准确性误差依次为 0 . 6nm ,1. 2nm ,1. 4nm。各检测器对苯及其同系物的扫描光谱图 ,体现检测器较高的光谱分辨率。实验结果表明 :这种新型系列二极管阵列检测器的性能指标良好 ,满足设计需要 ,可作为高效液相色谱检测器使用。     

GMR array uniform eddy current probe for defect detection in conductive specimens

The usage of eddy current probes (ECP) with a single magnetic field sensor represents a common solution for defect detection in conductive specimens but it is a time consuming procedure that requires huge amount of scanning steps when large surface specimens are to be inspected. In order to speed-up the nondestructive testing procedure, eddy current probes including a single excitation coil and an array of sensing coils present a good solution. The solution investigated in this paper replaces the sensing coils for giant magneto-resistors (GMRs), due to their high sensitivity and frequency broadband response. Thus, the ECP excitation coil can be driven at lower frequencies than the traditional ones allowing defects to be detected in thicker structures.In this work an optimized uniform eddy current probe architecture including two planar excitation coils, a rectangular magnetic field biasing coil and a GMR magnetometer sensor array is presented. An ac current is applied to the planar spiral rectangular coil of the probe, while a set of GMR magnetometer sensors detects the induced magnetic field in the specimens under test. The rectangular coil provides the DC uniform magnetic field, assuring appropriate biasing of the GMR magnetometers of the probe, setting-up the functioning point on the linear region and at the same branch of the GMR static characteristics. The differences on the images obtained for the same specimen for each GMR are reduced if all sensors are biased on the same working point. Elements of the automated measurement system used to inspect the plate under test using the proposed eddy current probe, including a validation procedure based on a 2D template matching algorithm and the corresponding experimental results are included in the paper.     

Support-vector-regression-based prediction of water holdup in horizontal oil-water flow by using a bicircular conductance probe array

This paper presents a water holdup prediction method based on support vector regression (SVR) for horizontal oil-water two-phase flow when using a bicircular conductance probe array that consists of 24 conductance probes. The support vector machine (SVM) was employed to establish a nonlinear SVR model mapping the probe array responses into water holdup directly. Experiments were carried out in the 16 m long and 125 mm inner diameter horizontal pipe of an industrial scale experimental setup. The experimental data obtained under 220 flow conditions were first divided into modeling data set and comparing data set. The modeling data set is used for establishing a nonlinear SVR and a linear least squares regression (LSR) models, while the comparing data set is used for comparing both models with the equi-weight and optimal weight estimate methods. Comparison results obtained by using the comparing data set show that when the binary data of the probes’ responses are used only, the measurement accuracy of the optimal weight estimate method is the best. If the analog data can be obtained, the measurement accuracy of both regression methods are better than those of both weighting estimate methods, especially, the nonlinear SVR method provide the best measurement accuracy.     

超声阵列式地下储气井专用检测系统

地下储气井的长期使用存在被锈蚀乃至爆井的危险.一种探测锈蚀程度的机电结合装置已被研制出来.测量在除去井盖的条件下进行.装置中设计了一个81阵元超声阵列探头组件,和一套匀速提升及注水(10 MHz超声耦合剂)的机械构件.电路上以频率步进脉冲调制方式,通过数字正交化、幅度均衡化以及脉冲压缩等技术的处理,获得井壁厚度探测的较...     

Coaxial arrangement of a scanning probe and an X-ray microscope as a novel tool for nanoscience

We report on the design and first tests of a novel instrument aimed at combining the benefits of scanning force microscopy with those of X-ray spectroscopy. For this we built an instrument combining a scanning transmission X-ray microscope with a beam-deflection atomic force microscope in a coaxial geometry. This allows to combine X-ray absorption spectroscopy and high resolution topography in-situ. When replacing the conventional scanning probe tip by a coaxially shielded tip the instrument will allow detection of the photoelectrons produced by resonant X-ray absorption. This could yield spectroscopic information with a spatial resolution approaching the values achievable with atomic force microscopy.