数码成像比色法探究反应物浓度对化学反应速率的影响

利用数码成像比色法探究反应物浓度对化学反应速率的影响,采用紫红色溶液互补光"绿"通道的亮度值-时间的曲线变化表征反应物浓度与化学反应速率的关系。同时也利用分光光度计研究反应物浓度与反应速率的关系,测出透光率-时间的曲线变化。从实验结果比较分析,用数码成像比色法探究反应物浓度对化学反应速率的影响是非常简便可行的方法,同时让学生使用随身所带的电子产品开展实验研究,不仅使实验教学具有趣味性和科学性,而且能更好地培养学生的创新潜质。     

Immobilization of Bovine Serum Albumin on Polytetrafluoroethylene for Application as a Potential Solid Support for Biosensor Development with Visual Detection

Immobilization of biomolecules on polymers is attractive for developing new biosensors and analytical methods. Polytetrafluoroethylene, PTFE (Teflon), is a low-cost polymer that has unique chemical and physicochemical properties. In this work, PTFE was investigated as a solid support for biosensor development. Bovine serum albumin (BSA) was immobilized directly on PTFE thin films without pretreatment. BSA was biotinylated, while the immobilization was controlled by the formation of visual spots using either streptavidin–fluorescein or streptavidin–gold nanoparticle conjugates. The visualization of the spots was accomplished by the naked eye (red spots) or a digital camera that captures the emitted fluorescence (green spots). The signal-to-background ratio was determined for both detection systems and was equal to 24.4 and 58.4 for streptavidin–fluorescein and streptavidin–gold nanoparticles, respectively.     

Paper-based diagnostic platforms and devices

Paper-based analytical devices have become lately “must have” components in equipment and instrumental designed for point-of-care applications, especially when they are used in tandem with microfluidic platforms. Nowadays, paper-based electrochemical devices (PEDs) represent the first choice in the development of lab-on-a-chip biosensors because of their benefits in biomedical diagnosis in terms of simplicity, affordability, portability, and disposability. Moreover, cellulose is a biodegradable and biocompatible substrate, ideal for building disposable devices for use in remote locations or low-resource settings. Despite their low costs and simplicity, PEDs must face a tough challenge—meeting the affordable, sensitive, specific, user-friendly, rapid and robust, equipment-free, and deliverable to end users criteria. The latest achievements in microfluidic PEDs for clinical diagnosis will be critically discussed, putting emphasis on innovative assay formats and methods for surface modification.     

DMZ内视场光学分割型航摄相机子影像高准确度几何拼接

针对内视场光学分割型相机,利用子影像同名像点虚拟影像坐标相等这一约束条件,提出一种高准确度子影像几何拼接方法.首先在分析各CCD几何安置误差的基础上,设计拼接关系并给出拼接参量计算方法;其次结合SIFT等高准确度影像匹配算子对拼接模型进行优化选择,给出子影像拼接流程;最后采用附加参量自检校技术进行畸变参量再精化处理.利用所提方法对一款自行设计的数字大面阵复合相机进行几何拼接试验,结果表明该方法能够有效解决高准确度子影像几何拼接、高量测性能大幅面虚拟影像生成问题,拼接后影像内符准确度可达子像元级,满足航测作业对数字航摄相机测图准确度和摄影效率的应用要求.     

On-line conveyor belts inspection based on machine vision

Under the background that mining conveyor belts are prone to failure in operation, the on-line fault detection technique based on machine vision for conveyor belts is investigated. High-brightness linear light sources arranged to a vaulted shape provide light for a line-array CCD camera to capture high-quality belt images. A fast image segmentation algorithm is proposed to deal belt images on-line. The algorithm for detecting longitudinal rip and belt deviation which are serious threat to the mine safety production from binary belt images is presented. Then, an on-line visual belt inspection system is developed. The laboratory testing results testify the validity of the visual inspection system.     

基于矩阵变换的光场成像及重聚焦模型仿真

基于光场的两平行平面表示方法,针对光场相机两参考平面间的共轴空间距离变换、离轴空间距离变换、轴旋转和沿轴旋转以及透镜作用等对光线描述方式的影响,给出了相应的光场矩阵变换方程,并利用这些方程,建立了光场相机的成像模型、采样模型及辐射传输模型.从光场共轴空间距离变换的观点出发推导出可实现不同点清晰成像的数字重聚焦公式.利用所建立的模型,计算机仿真生成了目标景物,并用所建立模型对生成景物进行了数字重聚焦,验证了数字重聚焦后的图像与直接聚焦图像的一致性.     

High-accuracy and real-time 3D positioning,tracking system for medical imaging applications based on 3D digital image correlation

This paper presents a system for positioning markers and tracking the pose of a rigid object with 6 degrees of freedom in real-time using 3D digital image correlation, with two examples for medical imaging applications. Traditional DIC method was improved to meet the requirements of the real-time by simplifying the computations of integral pixel search. Experiments were carried out and the results indicated that the new method improved the computational efficiency by about 4–10 times in comparison with the traditional DIC method. The system was aimed for orthognathic surgery navigation in order to track the maxilla segment after LeFort I osteotomy. Experiments showed noise for the static point was at the level of 10⁻³ mm and the measurement accuracy was 0.009 mm. The system was demonstrated on skin surface shape evaluation of a hand for finger stretching exercises, which indicated a great potential on tracking muscle and skin movements.     

On the shape of the fringe of various types of random trees

We analyze a fringe tree parameter w in a variety of settings, utilizing a variety of methods from the analysis of algorithms and data structures. Given a tree t and one of its leaves a, the w(t, a) parameter denotes the number of internal nodes in the subtree rooted at a's father. The closely related w?(t, a) parameter denotes the number of leaves, excluding a, in the subtree rooted at a's father. We define the cumulative w parameter as W(t) = Σ_aw(t, a), i.e. as the sum of w(t, a) over all leaves a of t. The w parameter not only plays an important rôle in the analysis of the Lempel–Ziv '77 data compression algorithm, but it is captivating from a combinatorial viewpoint too. In this report, we determine the asymptotic behavior of the w and W parameters on a variety of types of trees. In particular, we analyze simply generated trees, recursive trees, binary search trees, digital search trees, tries and Patricia tries. The final section of this report briefly summarizes and improves the previously known results about the w? parameter's behavior on tries and suffix trees, originally published in one author's thesis (see Analysis of the multiplicity matching parameter in suffix trees. Ph.D. Thesis, Purdue University, West Lafayette, IN, U.S.A., May 2005; Discrete Math. Theoret. Comput. Sci. 2005; AD :307–322; IEEE Trans. Inform. Theory 2007; 53 :1799–1813). This survey of new results about the w parameter is very instructive since a variety of different combinatorial methods are used in tandem to carry out the analysis. Copyright © 2008 John Wiley & Sons, Ltd.     

全数字低温漂差动电容检测技术

为降低微小差动电容检测电路的复杂度，提高检测结果的温度稳定性，提出了一种结构简单，无总移相器、滤波器、解调器的全数字检测硬件平台；然后以此硬件平台为基础，设计了检测结果与检测激励信号幅值无关，无总稳幅及温度补偿电路的检测算法。将该技术应用于某差动电容型电子水平仪进行一次启动长期稳定性试验，结果表明在连续24 h内温度变化达12℃时，水平仪的输出变化不超过±1个字（±0.5″），具有优异的温度稳定特性。该技术还可应用于其他任意采用单频正弦信号进行激励的微弱信号检测，如动调陀螺信号检测、微位移传感器信号检测等。