ICS—20皮带秤在挥发窑配料中的应用

主要介绍了ICS--20型电子皮带秤在我厂挥发窑配料中的应用．阐述了其工作原理．组态方法、校准步骤及维护方法．     

西门子MMI-2电子皮带秤在锦丰矿业公司的应用

电子皮带秤作为一种在线称量仪表,要求运行稳定、精度高、重复性好。详细介绍了西门子MMI-2电子皮带秤的工作原理和特点。针对安装过程中影响电子皮带秤测量精度的因素,通过合理布置秤架、调校称重传感器等措施,减小了电子皮带秤安装时导致的误差,提高了电子皮带秤的测量精度和重复性。在此基础上,通过实物验证,进一步提高了电子皮带秤的测量精度,将测量误差控制在±0.25%以内,满足工艺使用要求。     

消除皮带秤零点与斜率相互影响的校准方法

济钢炼铁厂400㎡烧结机在校秤程序设计上,采用了＂校秤时间内瞬时零点电流的累积量＂作为零点值,在修正零点值时不会影响斜率,修改斜率时也不影响零点,满足了校秤过程标准,且能够在不停机、不停产的情况下对备用皮带秤校准零点,缩短了校准时间,简化了校准过程。     

冶金行业皮带秤应用的难点和应对措施

在冶金行业使用的多数皮带秤的运行状况不能令人满意,特别是一些用于进厂原料、成品计量和厂际间物料交接计量等要求高准确度计量的皮带秤,往往因准确度过低不能满足现场要求。在介绍了冶金行业皮带秤应用的特点、难点后,着重论述了国产皮带秤应用技术的新发展、高准确度计量皮带秤应用难点和可以采取的应对措施。     

带校验装置的电子皮带秤系统

该文阐述了一套带校验装置的单悬臂多托辊式电子皮带秤系统。计量皮带机分三段,前后两端是缓冲段,中间是称量段,全长7米。投运前先用标准砝码将料斗秤标定好,然后借助经料斗电子秤检斤的实物来校准电子皮带秤。经一年多全面考核,性能稳定,计量误差小于1％。     

复合式计量皮带秤在酒钢的应用

目前,酒钢大部分皮带秤计量精度不能控制在±1.0%之内,已不能完全满足精准计量的要求,为此,应用铜陵三爱思公司复合式计量皮带秤,利用其优势以克服传统皮带秤的缺点,以保证皮带秤运行稳定,实现准确计量的要求。     

电子皮带秤的应用及使用维护要点

本文介绍了电子皮带秤的发展历史及结构原理，分析了皮带秤在自动配料过程中的控制原理，并详细阐述了电子皮带秤的常见故障、处理方法和日常维护要点。     

HZC—1型智能核子皮带秤

本文叙述了核子皮带秤的工作原理、技术特性、结构特点和定标方法。并对首钢HZC-1型核子皮带秤和美国6000X型核子皮带秤的主要性能作了比较。     

金属标准物质中杂质的辉光放电质谱法溯源分析

标准物质定值分析的溯源性要求比常规分析高很多。在常规分析中,有证标准物质（CRM）可用于校准以及建立可溯源性。尽管与标准物质生产和认定相关的ISO导则并没有十分明确地提到校准,但众多标准物质生产者在定值分析时却不接受基准标准物质用于校准。这些要求制约了标准物质定值方法的使用,因为这些方法可以采用已知高纯度的标准物质、化学计量法及已知高纯度标准物质的混合物进行校准。有效的固体取样技术,例如通常使用的块状标准物质进行校准的辉光放电质谱法（GD MS）或火花源发射光谱法（spark OES）,似乎不太适合定值分析。尤其是固体样品中痕量元素分析测定的有力工具辉光放电质谱法,除金属杂质外,使用特定气体混合物,这种方法也可以分析相关的非金属杂质如硫和磷。我们开发了一种可以使用已知高纯度的标准物质混合物和化学计量法的校准方法,这种校准方法同样可用于辉光放电质谱法。与溶液中基体匹配技术类似,此校准方法基于掺杂的粉末压片。本文还结合铜和钢标准物质的定值分析结果进行了陈述。     

有关皮带秤应用问题的思索

皮带秤是一种动态称重仪表,应用难度较大,使用者在实际使用过程中常常遇到皮带秤性能不稳定、精确度差等问题,这些问题与皮带秤的选用、现场安装密切相关.本文阐述了有关皮带秤应用中的几个具体问题的思索:如皮带秤的选用,皮带秤应用的关键技术,皮带秤厂商的选择,皮带秤的精度,皮带秤知识的获取等.     

接触式板形仪通用动态测试标定平台的开发与应用

介绍了三种典型接触式板形测量仪的结构组成、测量原理及其校正装置,开发了一套通用板形仪动态模拟标定平台,并给出了使用步骤。实验结果表明,该平台稳定可靠,标定方法实用有效,并可对板形仪进行各种补偿算法测试。     

Flat and curved crystal spectrography for mammographic X-ray sources

The demand for improved spectral understanding of mammographic X-ray sources and non-invasive voltage calibration of such sources has led to research into applications using curved crystal spectroscopy. Recent developments and the promise of improved precision and control are described. Analytical equations are presented to indicate effects of errors and alignment problems in the flat and curved crystal systems. These are appropriate for all detection systems. Application to and testing of spectrographic detection (using standard X-ray film) is presented. Suitable arrangements exist which can be used to measure X-ray tube voltages well below 1 kV precision in the operating range of 20-35 kV.     

Three-dimensional reconstruction: methods of improving image registration and interpretation

(i) Image registration. The use of serial images for computerised three-dimensional reconstruction necessitates the inclusion of three separate sources of information at the stage of data input. These are (i) artificial registration points or fiducials, (ii) a calibration scale and (iii) an outline of each slab of the section to be included in the reconstruction. Most traditional methods rely on the production of drawings of the contours of the structure under investigation which also include both registration points and a calibration scale. We report on a method which considerably reduces the time involved at this labour intensive stage of reconstruction and in addition allows subsequent reconstructions of different structures to be performed without new drawings. Use is made of computerised alignment of tissue sections and the production of composite photomicrographs of both the tissue under investigation and an accurately registered stage micrometer scale. (ii) Improving image interpretation. Images derived from computerised three-dimensional reconstruction can be affected by the number of coordinates used to form the contour of each slice of a structure and by the number of slices that are used to construct the final model. Too little or too much data can considerably reduce the ability of the observer to interpret accurately the image generated by the computer. We report on a feature-based method which enables the experimenter to assess objectively the amount of data required in the two-dimensional plane, i.e. the number of data points per slice, and the three-dimensional plane, i.e. number of slices per structure, so that optimal reconstructions are generated.     

Sensorimotor alignment effects in the learning environment and in novel environments.

Four experiments investigated the conditions contributing to sensorimotor alignment effects (i.e., the advantage for spatial judgments from imagined perspectives aligned with the body). Through virtual reality technology, participants learned object locations around a room (learning room) and made spatial judgments from imagined perspectives aligned or misaligned with their actual facing direction. Sensorimotor alignment effects were found when testing occurred in the learning room but not after walking 3 m into a neighboring (novel) room. Sensorimotor alignment effects returned after returning to the learning room or after providing participants with egocentric imagery instructions in the novel room. Additionally, visual and spatial similarities between the test and learning environments were independently sufficient to cause sensorimotor alignment effects. Memory alignment effects, independent from sensorimotor alignment effects, occurred in all testing conditions. Results are interpreted in the context of two-system spatial memory theories positing separate representations to account for sensorimotor and memory alignment effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Empirical estimation of the reliability of ribosomal RNA alignments

MOTIVATION: The automatic alignment of rRNA sequences can reproduce manual expert alignments with high, but not perfect, fidelity. We examine the use of empirical methods for the identification of regions of an alignment of a new sequence with an existing large alignment which can confidently be predicted to be correctly aligned. RESULTS: We show how to use a simple jack-knife procedure to derive an estimate of the reliability that is to be expected at each position of a large alignment of eukaryotic rRNA sequences. These reliabilities are then improved using measures that are specific to the input sequence. Regions where the sequence-specific reliability method performs particularly well are identified and seen to correspond with elements in the structure of the rRNA molecules that vary between species in the alignment. We also compare these reliability measures to an algorithmic alignment stability measure. AVAILABILITY: The software is available free of charge by sending an e-mail message to emmet@chah.ucc.ie. CONTACT: emmet@chah.ucc.ie     

A genetic algorithm for multiple molecular sequence alignment

MOTIVATION: Multiple molecular sequence alignment is among the most important and most challenging tasks in computational biology. The currently used alignment techniques are characterized by great computational complexity, which prevents their wider use. This research is aimed at developing a new technique for efficient multiple sequence alignment. APPROACH: The new method is based on genetic algorithms. Genetic algorithms are stochastic approaches for efficient and robust searching. By converting biomolecular sequence alignment into a problem of searching for optimal or near-optimal points in an 'alignment space', a genetic algorithm can be used to find good alignments very efficiently. RESULTS: Experiments on real data sets have shown that the average computing time of this technique may be two or three orders lower than that of a technique based on pairwise dynamic programming, while the alignment qualities are very similar. AVAILABILITY: A C program on UNIX has been written to implement the technique. It is available on request from the authors.     

Protein structure prediction by threading. Why it works and why it does not

We developed a novel Monte Carlo threading algorithm which allows gaps and insertions both in the template structure and threaded sequence. The algorithm is able to find the optimal sequence-structure alignment and sample suboptimal alignments. Using our algorithm we performed sequence-structure alignments for a number of examples for three protein folds (ubiquitin, immunoglobulin and globin) using both "ideal" set of potentials (optimized to provide the best Z-score for a given protein) and more realistic knowledge-based potentials. Two physically different scenarios emerged. If a template structure is similar to the native one (within 2 A RMS), then (i) the optimal threading alignment is correct and robust with respect to deviations of the potential from the "ideal" one; (ii) suboptimal alignments are very similar to the optimal one; (iii) as Monte Carlo temperature decreases a sharp cooperative transition to the optimal alignment is observed. In contrast, if the template structure is only moderately close to the native structure (RMS greater than 3.5 A), then (i) the optimal alignment changes dramatically when an "ideal" potential is substituted by the real one; (ii) the structures of suboptimal alignments are very different from the optimal one, reducing the reliability of the alignment; (iii) the transition to the apparently optimal alignment is non-cooperative. In the intermediate cases when the RMS between the template and the native conformations is in the range between 2 A and 3.5 A, the success of threading alignment may depend on the quality of potentials used. These results are rationalized in terms of a threading free energy landscape. Possible ways to overcome the fundamental limitations of threading are discussed briefly.     

Progressive multiple alignment with constraints

A progressive alignment algorithm produces a multialignment of a set of sequences by repeatedly aligning pairs of sequences and/or previously generated alignments. We describe a method for guaranteeing that the alignment generated by a progressive alignment strategy satisfies a user-specified collection of constraints about where certain sequence positions should appear relative to others. Our main result is an algorithm to compute just the "prime" constraints that are implied by the user-given constraints; these are shown to be precisely the constraints that the alignment algorithm must obey. In practice, the time required to handle constraints is negligible and frequently much less than the time saved because the constraints permit searching a restricted region of the dynamic-programming grid. An alignment of the beta-like globin gene cluster of several mammals illustrates the practicality of the method.     

Single- and Multievent Optimization in Combined Sewer Flow and Water Quality Model Calibration

Over the last three decades, storm-water quality modeling has been used increasingly commonly to describe the general system behavior and assess the pollution loads transferred in and spilled out of combined sewer systems. The calibration of quality models is, in most cases, based on conventionally obtained calibration data, e.g., by automated sampling. Long-term high-resolution online measurement data are available for the Graz West catchment (Graz, Austria), allowing an assessment of the full dynamics of discharge and pollution concentrations. This paper focuses on the application and comparison of single-event and two different multievent optimization schemes for sewer-water quality model calibration. While both single- and multievent optimization lead to satisfying results for the calibration events in discharge calibration, it is shown that validation events are better reproduced by using multievent calibration. Single- and multievent autocalibration of pollution concentration is based on the best dataset obtained from the discharge calibration. As for discharge, the pollutographs are reproduced satisfactorily, and multievent calibration is more stable. In all cases, the two multievent approaches performed equally well.