Analysis of coal blends by automated microscopy

The relative efficiency of coal blend analyses by automated reflectance measurement techniques is compared with an optimum point counting method. The influence of overlapping reflectance distributions and the advantage of image analyser systems over point reflectance measurements are evaluated. Automated point reflectance measurement techniques are feasible for coal blend analysis provided the measurement time is sufficiently small, while image analyser instruments can gain an advantage by reducing the particle top size in the specimen preparation.     

新型全自动密度仪在煤及焦炭真相对密度测定中的应用

介绍基于新型氦气替换法的全自动密度仪的基本原理和主要功能,利用该仪器对煤及焦炭真相对密度进行测试,同时针对仪器的精确度和稳定性数据和GB217方法进行比较,验证该仪器的性能可靠性。     

Measurement of geometrical parameters in cocontinuous polymer blends: 3D versus 2D image analysis

Formulae of stereology are used to estimate 3D geometrical parameters of cocontinuous structures measured from 2D micrographs of polymer blends. 3D images of symmetric and nonsymmetric polymer blends made of fluorescently labelled polystyrene and styrene‐ran‐acrylonitrile copolymer were obtained with laser scanning confocal microscopy. Geometrical parameters of the blend interface, specifically volume fraction, surface area per unit volume (S _V ) and average of local mean curvature were measured directly from the 3D images and compared to the values estimated from analysis of a number of 2D slices combined with stereological relations. When the total length of phase boundary considered in the analysis of the 2D slices (L_Tot ) was at least 6000 times bigger than the characteristic length of the microstructure (S^?1_V ), the standard deviation for all the parameters measured became negligible. However, considerable discrepancies between the average values computed from 3D and 2D images were observed for any value of L_Tot . The mean curvature distribution was also measured from both the 3D images and the 2D slices. The distribution was estimated from the 2D slices but with a width about 2.4 times that of the true value obtained from the 3D images.     

Optimization of the film coating process for polymer blends by the grey-based Taguchi method

The purpose of this paper is to find the optimum conditions of the film coating process for polymer blends and the influence of major processing parameters on the morphological properties of the material surface has been discussed. The surface roughness is regarded as the target characteristic of the smaller-the-better system. In order to achieve the aim of the multiple-response process of robustness, the grey-based Taguchi method is proposed. Nine experimental trials based on the L₉(3⁴) orthogonal array are conducted to determine the optimum processing conditions, the significant factor levels, and the percent contributions together with the analysis of variance (ANOVA). Also, confirmation experiments are performed to verify that the experimental results are reproducible. Moreover, atomic force microscopy (AFM) can be carried out with 3D atomic resolution in air for the measurement and analysis of the precision surface .     

Monitoring of coal separation in a jig using a radiometric density meter

This paper discusses the application of a radiometric density meter to monitor the coal separation process in a jig. The signal from the meter can be used to evaluate the degree of coal grain loosening during cyclic water pulsations and to determine the separation density in the jig. The signal from the radiation detector is highly variable due to stochastic decay of the radiation source and various changes in media density. The paper shows how to optimize the analogue and discrete filters applied in an electronic circuit of a density meter. The minimum dynamic error of measurement can be achieved if their parameters adapt to changes in the measured density. The authors present results of industrial tests carried out on the jig control system with the radiometric density meter.     

Microscopy of sclerotinites in the coal beds of the central part of the Appalachian coal field,U.S.A

Rodlets from fusain and carbominerite bands or lenses in bituminous coal beds of the central part of the Appalachian coal field in the eastern United States were studied in three dimensions using both light microscopy and scanning-electron microscopy (SEM). Infrared studies and chemical analyses complemented reflectance measurements. The rodlets are found strati-graphically from the Pocahontas no. 3 coal bed (Pocahontas Formation, Lower Pennsylvanian or Namurian B & C) to the Washington coal bed (Washington Formation, Lower Permian). The most common rodlets are noncellular, range in diameter from 60 to 440 μm, and, when polished, have the relief and high reflectances typical of the inertinite maceral group. They have characteristic notches, ovoid shapes, distinctive fracture patterns, dense (oxidized) rims, vesicles, cavities and canals, some of which contain minerals (tentatively identified by SEM semiquantitative X-ray and infrared analyses). Some rodlets show a cellular cast on their longitudinal surfaces. Due to different exposures in variously-oriented polished sections, this type of rodlet is classified as sclerotinite of the inertinite maceral group. Comparison of the sclerotinites from the central part of the Appalachian coal field with the fusinitized resin rodlets from coal and coal balls of the Illinois basin (Kosanke & Harrison, 1957) and with the ‘sclerotioids’ of the St Rose no. 5 coal of Nova Scotia indicates that they represent the same bodies. All are interpreted to be rodlets of resinous origin belonging to one or more of the genera of medullosan seed ferns of Carboniferous and Permian age. We suggest using the existing terms ‘resino-sclerotinite’ and ‘fungo-sclerotinite’ for two distinct maceral varieties of the inertinite maceral group because of their distinguishing properties and their different paleobotanical origins. Two types of cellular rodlets, woody splinters and sclerenchyma strands, are also documented in this study because of their close association with the resino-sclerotinites of the central part of the Appalachian coal field.     

Current uses of fluorescence microscopy in coal petrology

Fluorescence analysis of the liptinite maceral content of various U.S. coal seams has shown that these macerals are consistently under-counted in conventional white-light analysis. Fluorescence analysis revealed a greater variety of liptinite macerals as well as a large amount of fluorescing vitrinite in all of the coals studied. However, pseudovitrinite was not observed to fluoresce. Textures and structures not visible in normal viewing are also seen in fluorescence analysis. Quantitative spectral analysis of single coals has shown that most liptinite macerals can be both petrographically and statistically separated on the basis of fluorescence parameters, with the wavelength at maximum intensity and the red/green quotient being the most significant. In coals of the Illinois Basin, one or more forms of fluorinite, resinite, sporinite and cutinite can be distinguished. As the rank of the coal increases, the fluorescence intensity decreases and the spectral maxima shift toward longer wavelengths. In some Rocky Mountain coals these effects occur at a much lower rank (<0.85% reflectance) than in the coals of the Appalachian Basin. Similar changes in fluorescence properties have also been found in naturally weathered coals. Fluorescence analysis of resinite-rich Rocky Mountain coals has shown that two major forms of resinite are present; one is the ‘normal’ resinite, and the other is a much more abundant fissure-filling resinite that carries coal xenoliths, shows flow structure, and has a spectral maximum well below that of the ‘normal’ resinite.     

A quantitative comparison of synaptic density following perfusion versus immersion fixation in the rat cerebral cortex

The main objective of the present study was to perform an unbiased comparison of immersion vs. perfusion techniques to assess whether we could use the former to quantify synapses through electron microscopy (EM). Using the immersion technique is ideally suited for instances in which the specimen under study could not be perfused under the standard EM protocol. Our results suggest that, despite suboptimal qualitative results, fixation by immersion allows for adequate quantification of synapses.     

Application of a Taguchi-based neural network prediction design of the film coating process for polymer blends

In this paper, an approach for developing the prediction model for polymer blends using a back-propagation neural network (BPNN) combined with the Taguchi quality method is presented in an attempt to improve the deficiencies in current neural networks associated with the design of network architecture, including the selection of one optimal set of learning parameters to accomplish faster convergence during training and the desired accuracy during the recall step. The objective of the prediction model is to explore the relationships between the control factor levels and surface roughness in the film coating process. In addition, the feasibility of adopting this approach is demonstrated in the study optimizing the learning parameters of the BPNN structure to forecast the target characteristics of the product or process with various control conditions in the manufacturing system.     

Automatic macroscopic density artefact removal in a Nissl‐stained microscopic atlas of whole mouse brain

Acquiring a whole mouse brain at the micrometer scale is a complex, continuous and time‐consuming process. Because of defects caused by sample preparation and microscopy, the acquired image data sets suffer from various macroscopic density artefacts that worsen the image quality. We have to develop the available preprocessing methods to improve image quality by removing the artefacts that effect cell segmentation, vascular tracing and visualization. In this study, a set of automatic artefact removal methods is proposed for images obtained by tissue staining and optical microscopy. These methods significantly improve the complicated images that contain various structures, including cells and blood vessels. The whole mouse brain data set with Nissl staining was tested, and the intensity of the processed images was uniformly distributed throughout different brain areas. Furthermore, the processed image data set with its uniform brightness and high quality is now a fundamental atlas for image analysis, including cell segmentation, vascular tracing and visualization.     

Single molecule mapping of the optical field distribution of probes for near-field microscopy

The most difficult task in near-field scanning optical microscopy (NSOM) is to make a high quality subwavelength aperture probe. Recently, we have developed high definition NSOM probes by focused ion beam (FIB) milling. These probes have a higher brightness, better polarization characteristics, better aperture definition and a flatter end face than conventional NSOM probes. We have determined the quality of these probes in four independent ways: by FIB imaging and by shear-force microscopy (both providing geometrical information), by far-field optical measurements (yielding throughput and polarization characteristics), and ultimately by single molecule imaging in the near-field. In this paper, we report on a new method using shear-force microscopy to study the size of the aperture and the end face of the probe (with a roughness smaller than 1.5 nm). More importantly, we demonstrate the use of single molecules to measure the full three-dimensional optical near-field distribution of the probe with molecular spatial resolution. The single molecule images exhibit various intensity patterns, varying from circular and elliptical to double arc and ring structures, which depend on the orientation of the molecules with respect to the probe. The optical resolution in the measurements is not determined by the size of the aperture, but by the high optical field gradients at the rims of the aperture. With a 70 nm aperture probe, we obtain fluorescence field patterns with 45 nm FWHM. Clearly, this unprecedented near-field optical resolution constitutes an order of magnitude improvement over far-field methods like confocal microscopy.     

Fabrication of a versatile substrate for finding samples on the nanometer scale

With increasing interest in nanometer scale studies, a common research issue is the need to use different analytical systems with a universal substrate to relocate objects on the nanometer scale. Our paper addresses this need. Using the delicate milling capability of a focused ion beam (FIB) system, a region of interest (ROI) on a sample is labelled via a milled reference grid. FIB technology allows for milling and deposition of material at the sub 20-nm level, in a similar user environment as a standard scanning electron microscope (SEM). Presently commercially available transmission electron microscope (TEM) grids have spacings on the order 100 μm on average; this technique can extend this dimension down to the submicrometre level. With a grid on the order of a few micrometres optical, FIBs, TEMs, scanning electron microscopes (SEMs), and atomic force microscopes (AFM) are able to image the ROI, without special chemical processes or conductive coatings required. To demonstrate, Au nanoparticles of ∼ 25 nm in size were placed on a commercial Formvar^®- and carbon-coated TEM grid and later milled with a grid pattern. Demonstration of this technique is also extended to bulk glass substrates for the purpose of sample location. This process is explained and demonstrated using all of the aforementioned analytical techniques.     

发电厂输煤系统的带式输送机设计

阐述了国电谏壁发电厂2×1 000 MW机组扩建工程燃料系统中卸煤、加仓工作的实际情况及工作需求,介绍了输煤系统10号丙带式输送机的机型和部件选用以及部件设计及计算校核.该带式输送机投用后运行良好,取得了显著的效益.     

Mapping the chemistry of resinite,funginite and associated vitrinite in coal with micro‐FTIR

Micro‐FTIR mapping is a powerful tool for nondestructive, in situ chemical characterization of coal macerals at high resolution. In this study, the chemistry of resinite, funginite and associated vitrinite is characterized via reflectance micro‐FTIR for Cenozoic high volatile C bituminous coals from Colombia. In comparison with the micro‐FTIR spectra of vitrinite and inertinite, the corresponding spectra of liptinite macerals in the same coals are characterized by stronger aliphatic CH_x absorbance at 3000–2800 and 1460–1450 cm^?1, but less intense aromatic C=C ring stretching vibration and aromatic CH_x out‐of‐plane deformation at 700–900 cm^?1. The aliphatic components in resinite have the longest carbon chains and are least branched, bestowing the highest hydrocarbon generation potential on resinite among the three macerals studied. In contrast, funginite exhibits the strongest aromatic character, the highest aromaticity, the lowest ‘A’ factor values and the lowest C=O/C=C ratios among the three maceral groups. Vitrinite generally displays intermediate chemical characteristics. Reflectance micro‐FTIR mapping of coal samples further confirms the aliphatic character of resinite and the aromatic nature of funginite. In addition, chemical mapping of resinite and adjacent vitrinite shows that vitrinite immediately adjacent to resinite displays higher aliphatic CH_x stretching intensity than more distant vitrinite, suggesting that chemical components from resinite can diffuse over short distances into adjacent vitrinite, specifically causing hydrogen enrichment. It needs to be pointed out, however, that the region of influence is localized and limited to a narrow zone, whose extent likely depends on resinite's properties, such as its size and aliphatic material content. This way, the chemical map of resinite and associated vitrinite provides direct evidence of the intermaceral effects occurring during the peat forming stage or during later coalification. No influence of funginite (primarily fungal spores and sclerotia) on the chemistry of adjacent vitrinite has been demonstrated, which is likely due to the highly aromatic structure of this type of funginite.     

影响循环流化床锅炉碎煤机锤头和筛板使用寿命的因素及改进措施

从材质和结构两方面分析研究循环流化床锅炉碎煤机锤头和筛板磨损机理,针对磨损的主要原因进行材质和结构的改进,从而提高碎煤机的破碎效率,延长锤头的寿命,减少硬度大的大颗粒燃料在破碎机内留存时间,改进和优化破碎后的燃料粒度级配比例     

Inexpensive, high-quality optical relay for use in confocal scanning beam imaging

An inexpensive, high optical-quality relay lens made up of two eyepieces arranged in an afocal assembly for use in confocal scanning laser imaging is described. In the past we have used relays, within our confocal microscopes, made up of achromats with long focal lengths (> or = 10 cm), which take up large optical tracks and suffer from significant amounts of astigmatism and curvature of field. We quantify aberrations associated with achromat and eyepiece relays using CODE V optical design and analysis software. The eyepiece relay is found to be more compact, better corrected, and not significantly more expensive than its achromat counterpart. In addition to being used to interconnect two scanning mirrors optically as well as scanning mirrors with microscope objectives, it can form part of the optics in a confocal scanning laser MACROscope-Microscope system (Biomedical Photometrics, Inc., Waterloo, Ontario, Canada). Due to design constraints, the MACROscope-Microscope system cannot incorporate a conventional wide-field microscope into its structure such as is done in most commercial confocal microscopes. The eyepiece relay is used as a stand-alone, compact optical link between the scanning mirrors and the microscope objective. This consequently makes the MACROscope-Microscope system more compact and easier to commercialize.     

An inverse problem of estimating the heat source in tapered optical fibers for scanning near-field optical microscopy

A conjugate gradient method based on inverse algorithm is applied in this study to estimate the unknown space- and time-dependent heat source in aluminum-coated tapered optical fibers for scanning near-field optical microscopy, by reading the transient temperature data at the measurement positions. No prior information is available on the functional form of the unknown heat source in the present study; thus, it is classified as the function estimation in inverse calculation. The accuracy of the inverse analysis is examined by using the simulated exact and inexact temperature measurements. Results show that an excellent estimation on the heat source and temperature distributions in the tapered optical fiber can be obtained for all the test cases considered in this study.     

Correlative light‐electron fractography for fatigue striations characterization in metallic alloys

The correlative light‐electron fractography technique combines correlative microscopy concepts to the extended depth‐from‐focus reconstruction method, associating the reliable topographic information of 3‐D maps from light microscopy ordered Z‐stacks to the finest lateral resolution and large focus depth from scanning electron microscopy. Fatigue striations spacing analysis can be precisely measured, by correcting the mean surface tilting with the knowledge of local elevation data from elevation maps. This new technique aims to improve the accuracy of quantitative fractography in fatigue fracture investigations. Microsc. Res. Tech. 76:909–913, 2013. © 2013 Wiley Periodicals, Inc.     

基于光纤传感技术的矿井粉尘质量浓度检测

矿井内粉尘不仅对工人的健康具有很大危害,而且较高的粉尘质量浓度会引起爆炸事故。为了测量矿井内的粉尘质量浓度,鉴于光纤传感器的独特优势,提出了基于光纤传感技术的矿井内粉尘质量浓度检测系统。该系统利用光透射法,由双通道检测光路系统组成,利用MATLAB对测量数据进行理论分析,得出拟合曲线及公式。结果表明,系统具有良好的测量准确性和一定的实用价值。     

Quantitative method for estimating stain density in electron microscopy of conventionally prepared biological specimens

Stain density is an important parameter for optimising the quality of ultrastructural data obtained from several types of 3D electron microscopy techniques, including serial block-face electron microscopy (SBEM), and focused ion beam scanning electron microscopy (FIB-SEM). Here, we show how some straightforward measurements in the TEM can be used to determine the stain density based on a simple expression that we derive. Numbers of stain atoms per unit volume are determined from the measured ratio of the bright-field intensities from regions of the specimen that contain both pure embedding material and the embedded biological structures of interest. The determination only requires knowledge of the section thickness, which can either be estimated from the microtome setting, or from low-dose electron tomography, and the elastic scattering cross section for the heavy atoms used to stain the specimen. The method is tested on specimens of embedded blood platelets, brain tissue and liver tissue.