PLC定尺系统在炼钢厂5^#连铸生产中的研究与应用

为解决炼钢厂5^#连铸机的红外无接触定尺系统受火焰切割干扰较大，切割精度不高，经常造成铸坯长短尺的问题，开发了PLC定尺系统，很好地解决了定尺问题。介绍了PLC定尺系统的原理以及使用效果。     

热锯定尺机构优化改进

针对生产线上热锯定尺系统存在的缺陷，对定尺机构进行了适应性优化改进，满足了生产使用要求。     

非接触式方坯自动定尺切割装置的应用

为提高马钢第三炼钢厂连铸坯的定尺率和剪切精度，达到降本增效的目的，采用了非接触式方坯自动定尺切割装置，一年多的生产实践表明，其定尺率可稳定在９５％以上，较使用前约提高了８个百分点，效果令人满意。     

新型型钢定尺机

我国型钢厂目前使用的定尺机多种多样 ,它们各自使用在不同的场合。一种最近投产的 ,使用在新建型钢厂的框架式型钢定尺机 ,性能良好 ,比其他类型定尺机有着更多的优点。     

定尺机的改进

针对定尺机在使用中出现的问题，设计了一种改进方案，经使用效果明显。     

完善中板定尺收集工艺

通过分析影响中板定尺收集的各种因素，及时改造，完善定尺收集工艺，挽救了部分有缺陷、需要处理的钢板，提高了定尺率。     

定尺剪系统改造设计与应用

针对济钢2 500 mm轧钢产线定尺剪定尺误差大的问题,在原有基础上增添定尺机构,使用RS Logix 5000编程软件对硬件系统进行组态,采用MSG数据通信方式实现了多网络通信、定尺机自动定位、多电机同步减速控制,应用RS View设计上位画面,方便操作。应用表明,钢板定尺精度控制在±1 mm,提高了生产效率。     

横切机组定尺装置测量辊的改进

为了提高横切机组定尺装置的定尺精度，减少定尺误差，对该装置的结构、安装方式进行改进，对相关尺寸加以调整，改变定尺辊身的材质和支撑辊辊身的外国材料，从而提高了板材的成材率，取得了较好的经济效益。     

焊管生产线自动切除管头的设备改造

本文介绍了我厂中长带生产定尺焊管的现行定尺工艺，分析了该工艺的不足与缺点，并指了 所飞锯的提高定尺比方面的局限性，提出了提高尺比的方法与工作原理。     

首钢京唐连铸板坯激光测长系统设计及应用

首钢京唐炼钢连铸板坯的激光测长系统采用了非接触式测量，具有自动校正板坯定尺长度，实现智能闭环切割控制，定尺切割精度高，维护简单同时极大地减少由于测量轮机械磨损和人工测量直径误差等造成的板坯定尺与实际不符，整体提高了板坯的定尺合格率和成材率，该系统运行稳定，实际测量板坯长度与定尺偏差在合理范围内，完全满足现场生产工艺要求。     

Experimental and numerical investigation of the 3D SPECT photon detection kernel for non-uniform attenuating media

Experimental tests for non-uniform attenuating media are performed to validate theoretical expressions for the photon detection kernel, obtained from a recently proposed analytical theory of photon propagation and detection for SPECT. The theoretical multi-dimensional integral expressions for the photon detection kernel, which are computed numerically, describe the probability that a photon emitted from a given source voxel will trigger detection of a photon at a particular projection pixel. The experiments were performed using a cylindrical water-filled phantom with large cylindrical air-filled inserts to simulate inhomogeneity of the medium. A point-like, a short thin cylindrical and a large cylindrical radiation source of 99Tcm were placed at various positions within the phantom. The values numerically calculated from the theoretical kernel expression are in very good agreement with the experimentally measured data. The significance of Compton-scattered photons in planar image formation is discussed and highlighted by these results. Using both experimental measurements and the calculated values obtained from the theory, the kernel's size is investigated. This is done by determining the square N x N pixel neighbourhood of the gamma camera that must be connected to a particular radiation source voxel to account for a specific fraction of all counts recorded at all camera pixels. It is shown that the kernel's size is primarily dependent upon the source position and the properties of the attenuating medium through Compton scattering events, with 3D depth-dependent collimator resolution playing an important but secondary role, at least for imaging situations involving parallel hole collimation. By considering small point-like sources within a non-uniform elliptical phantom, approximating the human thorax, it is demonstrated that on average a 12 cm x 12 cm area of the camera plane is required to collect 85% of the total count recorded. This is a significantly larger connectivity than the 3 cm x 3 cm area required if scattering contributions are ignored and only the 3D depth-dependent collimator resolution is considered.     

Range estimation by optical differentiation

We describe a novel formulation of the range recovery problem based on computation of the differential variation in image intensities with respect to changes in camera position. This method uses a single stationary camera and a pair of calibrated optical masks to measure this differential quantity directly. We also describe a variant based on changes in aperture size. The subsequent computation of the range image involves simple arithmetic operations and is suitable for real-time implementation. We present the theory of this technique and show results from a prototype camera that we have constructed.     

Simulation study of the influence of collimator defects on the uniformity of scintigraphic images

The mechanical tolerances in building collimators for scintillation cameras are studied. A simulation method has been used to quantify the effects of defects in hole inclination and hole diameter on the uniformity of planar and tomographic images. The calculation takes into account the geometry of the hexagonal hole collimator, the camera intrinsic resolution, the object size, the pixel size, the effect of low-pass filtering, as well as the type, size and position of the defect. For instance, a 0.03 mm diameter defect on several holes located in the central region of a very high resolution collimator can result in a 12% uniformity artefact in tomographic imaging of an 18 cm diameter cylinder, using a 3.45 mm resolution camera, 4.5 mm pixel size, and Hamming filtering with a Nyquist frequency cut-off. A 0.17 degree inclination defect of a few holes can result in the same uniformity artefact. These results show that the building of a collimator has to be very precise.     

转炉水模分散相粒度分布的幂函数表征

通过二维水模型模拟转炉吹炼过程,利用数码相机进行摄影,通过对得到图像中分散相的提取与粒度的计算,应用幂函数法表征粒度分布,研究了顶吹转炉渣滴分散相粒度分布与边界条件的关系,得到了相应的比例关系。     

Kinetic PCR analysis: real-time monitoring of DNA amplification reactions

We describe a simple, quantitative assay for any amplifiable DNA sequence that uses a video camera to monitor multiple polymerase chain reactions (PCRs) simultaneously over the course of thermocycling. The video camera detects the accumulation of double-stranded DNA (dsDNA) in each PCR using the increase in the fluorescence of ethidium bromide (EtBr) that results from its binding duplex DNA. The kinetics of fluorescence accumulation during thermocycling are directly related to the starting number of DNA copies. The fewer cycles necessary to produce a detectable fluorescence, the greater the number of target sequences. Results obtained with this approach indicate that a kinetic approach to PCR analysis can quantitate DNA sensitively, selectively and over a large dynamic range. This approach also provides a means of determining the effect of different reaction conditions on the efficacy of the amplification and so can provide insight into fundamental PCR processes.     

转炉水模分散相尺寸分布的分形表征

 运用图像处理方法获得了分散相粒径和分散相几何特征,建立了一个用几何特征计算分散相分布分形维数的数学模型。数据图像的提取来源于模拟转炉吹炼过程的二维水模型,主要利用高分辨率数码相机采集数据,通过图像处理软件对得到图像中分散相进行提取与粒度计算,应用粒度分布分形维数模型,研究了在硬吹和软吹条件下顶吹转炉钢滴分散相粒度分布与边界条件的关系,证明了粒度分布分形维数数学模型的合理性。     

Magnification characteristics of fundus imaging systems

OBJECTIVE: To compare the magnification properties of 11 different fundus cameras (including 1 stereo fundus camera), a Rodenstock (infrared) scanning laser ophthalmoscope (SLO), the Heidelberg Laser Tomographic Scanner (LTS), and the Heidelberg Retina Tomograph (HRT). DESIGN: A cross-sectional study of the relationship between the true size of a fundus feature and its photographic-computer image in 14 different fundus imaging devices. This relationship was evaluated for each instrument using a model eye adjusted for axial ametropia between +11 diopter (D) and -14 D. To simulate refractive ametropia, the "crystalline lens" was removed to render the model eye aphakic, and the axial length was adjusted to give aphakic ametropia from emmetropia to +20 D. MAIN OUTCOME MEASURES: A correction factor (p) was calculated for each instrument, which can be used in calculations for determining true retinal size. RESULTS: The following were found to be of telecentric construction, Zeiss Oberkochen (WS240 Heidelberg), Zeiss Oberkochen (UK), Zeiss Oberkochen (Cologne), Nikon NF505, Kowa RCXV, SLO prototype (UK), LTS, and the HRT, and each exhibited a constant relationship between p and degree of ametropia of the model eye. The Canon CF6OU, Canon CF6OS, Canon CR4-45NM, Nidek 3-DX, Olympus GRCW, and Carl Zeiss Jena Retinophot were found not to be telecentric and exhibited a linear relationship between p and degree of ametropia of the model eye. For all instruments, p remained unchanged for axial and refractive ametropias of the same degree. CONCLUSIONS: The study has shown that not all fundus imaging systems are telecentric, so the use of a single magnification correction value may not be appropriate. These findings have important implications for the way in which true retinal size calculations are performed. Examples are given to show how the tabulated values of correction factors can be used for both telecentric and nontelecentric cameras in image size calculations.     

Conjugate imagery in the automated reproduction of three dimensional coordinates from two dimensional coordinate data

The three-dimensional video analysis of human motion commonly utilises automated image processing and digitisation processes to produce real-time unidentified two-dimensional coordinate data of segmental markers. In what can be a time-consuming process the two-dimensional data are then identified and tracked to produce three-dimensional coordinates. This paper presents an approach to the automated reproduction of three-dimensional coordinates from two-dimensional coordinates data. Conjugate imaging techniques were utilised in the development of four criterion measures for determining the validity of conjugate (corresponding) image points. An algorithm based on the criterion measures was then developed for the automated reproduction of three dimensional coordinates from camera image coordinate data. The algorithm was tested with a 55 point marker system viewed in four video cameras (digitisation error approx. 0.2%, lab point separation > or = 6 cm). The success of the algorithm was dependent on the closeness of markers, the accuracy of the photogrammetric system, and the number of markers visible in two camera images. The present research has developed techniques based on conjugate imagery for the automated reproduction of three-dimensional coordinates from two-dimensional data, and provided a bases for further development of automated three-dimensional tracking.     

Ultrastructural PMP22 expression in inherited demyelinating neuropathies

The purpose of this study was to determine the accuracy of a video system which our laboratory has been using to measure soft tissue strain. Both static and dynamic error analyses were performed to assess the accuracy of our video system. Static error was defined as the amount of movement reported by the video system for markers that were stationary. Dynamic error was defined as the difference between the motion of the markers as reported by the video system and their actual motion. Two sets of fluorescent markers were attached to a servo-hydraulic materials test machine. One marker set was attached to the hydraulic actuator (moving markers) and the other set was attached to the base of the machine (stationary markers). Five different marker sizes, five camera distances, and seven different loading rates were studied. Results indicated that the static error was independent of marker size, and that the dynamic error was independent of the loading rate and marker size for loading rates of 50% of the camera field of view (CFV) per second or slower. For loading rates greater than 50 percent of CFV per second, the marker size did have an affect on the dynamic error. The mean static error was found to be 0.026 percent of CFV and the mean dynamic error was found to be 0.062 percent of CFV.     

Path Planning and Control for Free-Flying Inspection Robot in Space

This paper describes a prototype robot called AERCam and the necessary path planning and control for its space inspection applications. The robot is the first generation of a free-flying robotic camera that will assist astronauts in constructing and maintaining the space station. The robot will provide remote views both to astronauts inside the space shuttle and the future space station and to ground controllers. The first part of the paper describes a planar robot prototype autonomously moving about an air-bearing table. The second part of this paper introduces a method for determining paths in three dimensions for efficient fuel use. Finally, this paper describes the software simulation of the path planner with the future space station.