Three-dimensional molecular distribution in single cells analysed using the digital imaging microscope

Cellular changes in molecular distribution are believed to underly a wide range of cell functions. In order to investigate changes in molecular distribution in single cells utilizing fluorescent probes we have developed a digital imaging microscope. The system, consisting of both hardware and software, automatically acquires 3-D data sets consisting of optical sections and then processes such data to facilitate the analysis of molecular distribution in single cells. The first major step in processing reverses distortion introduced principally by the optics of the fluorescent microscope. Various procedures for accomplishing this task are compared and a method based on regularization theory is shown to give superior results for several different 3-D images. Following this step features of interest are automatically extracted from 3-D images utilizing an artificial 3-D visual system. This artificial visual system utilizes a system of spatial filters to identify regional characteristics of images, the information obtained from these filters being used to identify and characterize clusters of molecules within the image. This information is then utilized to construct a 3-D graphical model of molecular distribution in single cells. Such models are displayed in 3-D and may be further analysed utilizing interactive 3-D computer graphics. These methods are illustrated by results obtained regarding alpha-actinin distribution in single smooth muscle cells.     

使用全场数据确定光弹材料条纹值的方法

光弹性实验中,材料条纹值是联系光学现象和材料应力的唯一参数,因而在每次实验前计量材料条纹值是非常必要的。条纹值的精确性与选取的实验计量点有密切的关联,同时应考虑残余双折射和残余应力的影响。根据实验获取的全场数据,在试件中选取多个点构成超定方程组,结合相移技术,运用最小二乘法确定材料条纹值。这种方法不仅能够确定条纹值,而且可以得到试样中残余应力的参数。最后,通过聚碳酸酯受压圆盘实验,验证了新方法的可行性。     

Analysis of density distribution for unsteady butane flow using three-dimensional digital speckle tomography

Transient and asymmetric density distributions have been investigated by three-dimensional digital speckle tomography. Multiple CCD images captured movements of speckles in three angles of view simultaneously because the flows were asymmetric and transient. The speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays for density gradients. The three-dimensional density fields have been reconstructed from the deflection angles by a real-time multiplicative algebraic reconstruction technique (MART).     

数字图像与数码相机噪声相关性的偏态分布

为了提高利用噪声相关性鉴别数字图像真伪的正确性,探索了描述噪声相关性偏态分布的最佳模型。首先,通过理论分析和大量实验验证了在(0,1]区间beta分布、gamma分布和对数正态分布可用于描述噪声相关性的偏态分布。然后,利用这3种分布的概率密度函数模拟实际的噪声相关性偏态分布的概率密度函数曲线,概率密度函数曲线的特征和最小错误率的大小说明了采用对数正态分布描述噪声相关性偏态分布的效果最佳,从而提出用对数正态分布描述噪声相关性偏态分布的模型。实验结果表明,与采用广义chi平方分布的模型相比,采用该模型可使最小错误率降低60%以上,证明了采用正确的模型描述噪声相关性偏态分布是降低鉴别错误率的有效途径。     

An autonomous digital complex for measuring the temperature distribution

An autonomous measuring complex has been designed for monitoring the distributed temperature field in the sea. The system includes a control and data storing module, a power supply, a timing system, and peripheral devices (DS-18B20 digital temperature sensors). The complex is based on the modular structure, which allows various configurations of sensors to be produced for each particular task with minimum expenses.     

Photographic recording and sharpening of isoclinics in photoelasticity

Various methods and combinations of methods correlating photoelastic and photographic techniques are discussed which tend to eliminate isochromatic influences from photoelastic patterns photographed in a plane crossed polariscope. Variable loading and white light with over-exposure of panchromatic high-contrast film or with exposure of Agfacontour film give best results in general. A method is described for determining isoclinic parameters point by point from special photographs of the combined isochromatic and isoclinic pattern so that the isoclinic lines need not be separated out of the combined pattern. In restricted regions of a combined pattern, where fringe orders are sensibly constant, isoclinic lines of two different parameters can be seen on a single high-contrast photograph or on a print of a developed Agfacontour film and the centre line between them can be extrapolated to give the isoclinic line corresponding to the setting of the analyser.     

Analysis of flow distribution from high-speed flow actuator using particle image velocimetry and digital speckle tomography

A variety of active flow control (AFC) methods are typically used in low-speed applications; however, the AFC techniques that are available for high-speed, supersonic applications are very limited. Under AFOSR (Air Force Research Laboratory) sponsorship, The Johns Hopkins University Applied Physics Laboratory (JHU/APL) is investigating a device that is intended for high-speed flow control; it is called the SparkJet actuator, which manipulates high-speed flows without active mechanical components. To date, actuator characterization has included computational and experimental techniques including parametric studies and flow visualization techniques to investigate the operation of the SparkJet device under various conditions. This paper focuses on the experimental flow measurement techniques that have been implemented. The results will be used for validating prospective computational studies that investigate the detailed characteristics of the SparkJet’s discharge and cooling stages after an energy deposition pulse. Current efforts include the use of high- resolution particle image velocimetry (PIV) to quantify the quiescent air operation of a single SparkJet pulse. However, the proper seeding of the SparkJet cavity continues to be challenging and has led to the use of digital speckle tomography (DST) to measure the temperature distribution in the core of the SparkJet plume. In this study, improved PIV techniques were used to acquire a higher-resolution image of the SparkJet-entrained flow. These PIV results show that the peak velocity in the entrained flow is around 53 m/s and the plume is sustained for 75–100 μs. Additionally, the DST data show a peak temperature of 1616.3 K at 75 μs and provide supporting information for interpreting the PIV data. These results are intended to calibrate and build confidence in a computational model.     

数控系统故障的几种诊断方法

介绍了几种数控系统故障诊断方法，并给出了实际例子，具有参考价值。     

飞机数字化装配测量系统研究

飞机数字化装配测量系统对飞机数字化装配工作有着重要的辅助作用,使得飞机装配定位工作更加简单、精确,对降低飞机制造成本、提高装配质量和装配效率有重要意义。分别从3个子系统即激光跟踪测量系统、数据处理系统和实时运动仿真系统,对飞机数字化装配测量系统进行研究和实现;实现了激光跟踪测量系统的初始化、数据采集和动态测量等功能,在对装配过程数据模型处理的矩阵分析研究的基础上,实现了装配场景的实时运动仿真,进行了装配件位置偏差的计算;通过实践检验,该系统能够运用于数字化装配工作中。     

Efficient work measurement system of manufacturing cells using speech recognition and digital image processing technology

Work measurement methods previously proposed require considerable time and effort by time study analysts because they have to measure the required time through direct observations. In this study, however, we propose a method which efficiently measures the standard times without involving human analysts by using speech recognition and digital image processing techniques. First, we implement a prototype system which can acquire the status of manufacturing cells through a speech recognition system. Second, using image processing, we suggest a method which consists of two main steps: motion representation and cycle segmentation. In the motion representation step, we first detect the motion of any object distinct from its background by differencing two consecutive images separated by a constant time interval. The images thus obtained then pass through an edge detector filter. Finally, the mean values of coordinates of significant pixels of the edge image are obtained. Through these processes, the motions of the observed worker are represented by two time series of data of worker location in horizontal and vertical axes. In the cycle segmentation step, we extract the frames which have maximum or minimum coordinates in one cycle, store them in a stack, and calculate each cycle time using these frames. In this step we also consider methods for detecting work delays due to unexpected events such as an operator’s movement out of the work area, or interruptions. To conclude, the experimental results show that the proposed method is very cost-effective and useful for measuring time standards for various work environments.     

Simultaneous collection and processing of energy-filtered stem images using a fast digital data acquisition system

A Vacuum Generators HB5 Scanning Transmission Electron Microscope which is coupled to a PDP 11/34 minicomputer has been used to simultaneously collect and store up to three digitized, energy-filtered images. The computer and interfacing hardware control the scan of the microscope's beam in synchronization with the scan coils of the energy analyzer so images can be obtained from different spectrometer windows. Replay of the images in conjunction with an Analogic AP400 hardware array processor makes it possible to extrapolate and suppress the background signal for each separate region of the specimen.     

病理切片全景扫描系统在科研中的应用

使用Leica SCN 400病理切片全景扫描系统可实现将载玻片信息自动、快速地转化为高质量数字化切片。这些高质量的数字化切片包含载玻片切片的全部信息,从而促进研究人员的分享、商讨、诠释以及报告和载剪使用。本文还讨论Leica SCN 400系统的优点和不足。     

数字接线盒在称重系统中的应用

利用数字化技术,将数字接线盒代替模拟接线盒,不仅能提高称重计量准确度,而且具有称重系统安装调试方便、电子元器件抗干扰能力强、数据传输距离远、系统自诊断和能及时确认传感器故障等特点.     

数字化制造中的信息质量问题研究

信息质量控制是数字化制造系统中的关键问题。从静态信息质量和动态信息质量的角度,分析了企业在实施信息化过程中存在的信息质量问题,论述了信息质量在数字化制造中所起的决定性作用。对当前信息质量研究中,信息质量维度的分类与定义、信息质量的控制技术与评价分析方法的现状进行了分析总结,提出了数字化制造中信息质量的研究方向。     

Near-infrared spectroscopy using digital phase-sensitive detection

Scanning near-infrared (NIR) spectrometers commonly employ analog lock-in amplifiers for demodulation that require complex circuitry and are sensitive to electromagnetic interference. Here, a new sampling system based on digital phase-sensitive detection is reported that used a quadrature sampling algorithm to establish the sampling frequency as an integral multiple of four times the optical signal frequency. A complex programmable logic device was used to control the analog-to-digital converter. A digital signal processor was used to receive data, complete the quadrature calculations, and transfer the results to a computer. Consequently, the circuitry was simplified with reduced electromagnetic interference. Spectra were obtained using instrumentation based on analog and digital sensitive detection that showed the latter provided more accurate results. The optimum signal-to-noise ratio of 66.34 dB was higher than the value obtained by the analog system.     

用FPGA设计数字频率计

该数字频率计的设计仅利用硬件描述语言来完成对系统功能的描述,在EDA工具的帮助下就可以得到最后的设计结果。所以尽管目标系统是硬件,但整个设计和修改过程如同完成软件设计一样方便和高效。     

Three-colour x-ray mapping using digital storage

Computer-controlled scanning of a scanning electron microscope (SEM) fitted with an energy-dispersive x-ray analyser has been carried out. This has been achieved by building an SEM interface module which controls the scanning of the electron beam and also provides a communication link between the x-ray analyser and an enhanced BBC micro. The digitised x-ray data pulses can be collected from three elements simultaneously to produce colour-coded x-ray distribution maps. Some such maps from two different specimens are presented and an effect of x-ray shadowing is clearly demonstrated. A comparison between images acquired using a frame size with 256 × 256 pixels and those with 128 × 128 pixels is made.     

Mooring alignment for marine SINS using the digital filter

Strapdown inertial navigation system (SINS) is presently used in several applications related to aerospace system and marine navigation. The accurate initial attitude is essential to ensure the precise determination of the position and attitude of the moving platform, which is usually calculated using initial alignment. When the vehicle is moored, the SINS inevitably experience disturbing motion. The method of ground coarse alignment, which is based on the assumption that SINS is on a stationary carrier with limited vibration, therefore cannot be used to perform the SINS mooring alignment. In this paper, a novel method processing the gyro and accelerometer measurements with infinite impulse response (IIR) digital low-pass filter to remove the high frequency noise is investigated for marine mooring alignment. Its algorithmic principle is described in details. The results obtained from both simulation and mooring experiment show that the attitude determined by this novel method can meet the accurate alignment.     

可重构数字系统资源调度方法

为实现可重构数字系统的快速重构,提高重构过程的自动化程度,提出了可重构模块的VME总线控制结构和自组织模型,以及基于指令序列的任务处理方法.在满足既定约束条件的前提下,建立了以模块消耗最少和资源利用率最高为目标函数的重构数学模型.将新任务分解为基于指令序列的关联子任务,使用粒子群算法将重构资源分配给新任务,以完成重构资源的调度.通过仿真实验验证了该方法的有效性.