Search

Tool-grade steels designed for the manufacture of hot-forming dies have been studied. An economically alloyed modified steel 70Kh3G2FTR(m) is proposed, which has a fine metal base structure with uniform carbide hardening in the heat-treated state. The comparative structural studies with traditional tool-grade steels (5KhGM, 4Kh5MFS) at different stages of heat treatment, as well as the statistical analysis of mechanical properties (hardness and toughness) from thermal hardening parameters, allowed us to develop an optimal heat treatment technology, which provided the required indicators for the structure, hardness, and heat resistance of the material. It is shown that 70Kh3G2FTR(m) steel retains its strength and the effect of microalloying at elevated operating temperatures, which is confirmed by data from transmission electron microscopy, dynamic mechanical analysis, and thermophysical properties in the field of operating temperatures up to 400 °C, as well as studies of the samples' texture under thermal exposure. The assessment of the mechanical properties, wear resistance, and economic effect of the introduction of the developed material and its thermal hardening technology make it possible to reasonably recommend 70Kh3G2FTR(m) steel as a rational replacement for traditional materials. [ABSTRACT FROM AUTHOR]

Here, a morphologically based approach is used for the in situ characterization of 3D growth rates of facetted crystals from the solution phase. Crystal images of single crystals of the β‐form of l‐glutamic acid are captured in situ during their growth at a relative supersaturation of 1.05 using transmission optical microscopy. The crystal growth rates estimated for both the {101} capping and {021} prismatic faces through image processing are consistent with those determined using reflection light mode [Jiang, Ma, Hazlehurst, Ilett, Jackson, Hogg & Roberts (2024). Cryst. Growth Des.24, 3277–3288]. The growth rate in the {010} face is, for the first time, estimated from the shadow widths of the {021} prismatic faces and found to be typically about half that of the {021} prismatic faces. Analysis of the 3D shape during growth reveals that the initial needle‐like crystal morphology develops during the growth process to become more tabular, associated with the Zingg factor evolving from 2.9 to 1.7 (>1). The change in relative solution supersaturation during the growth process is estimated from calculations of the crystal volume, offering an alternative approach to determine this dynamically from visual observations. [ABSTRACT FROM AUTHOR]

This paper describes a range of Paleozoic and Mesozoic mosses and assesses how far they can be referred to extant taxa at the family, ordinal, or class levels. The present study provides new data on Paleozoic mosses of the order Protosphagnales, re-evaluating affinities of some groups previously thought to be unrelated. The leaf areolation pattern, combined with the leaf costa anatomy, results in the subdivision of Protosphagnales into five separate families: Protosphagnaceae (at least six genera), Polyssaieviaceae (at least three genera), and three monogeneric families: Rhizonigeritaceae, Palaeosphagnaceae, and Servicktiaceae. We urge caution in referring Paleozoic and Early Mesozoic fossil mosses as members of Dicranidae and Bryidae, as they may belong to the extinct moss order Protosphagnales. Additional evidence supports the relation of the Permian genus Arvildia to extant Andreaeopsida. We segregate Late Palaeozoic and Early Mesozoic mosses that are superficially similar to extant members of either Dicranales or Polytrichales, into the artificial informal group of Archaeodicranids, distinguishing them from ecostate Paleozoic and Mesozoic mosses, which are combined here into another artificial informal group, Bryokhutuliinids. The latter includes the genus Bryokhutuliinia, widespread in contemporary Asia, from the Middle Jurassic to the Lower Cretaceous, as well as other superficially similar ecostate plants from different regions worldwide, ranging from the Upper Palaeozoic to the Lower Cretaceous. A list of Paleozoic, Mesozoic, and Eocene moss fossils suitable for age calibration in phylogenetic trees is provided. [ABSTRACT FROM AUTHOR]

This article is devoted to the development of a sliding burnishing scheme using a flat cylindrical indenter. The previously established patterns of nanostructured state formation in the AISI 52100 steel subsurface layer showed a need to create a special tool with a variable tilt angle of the indenter and with force regulation. A new tool with a cubic boron nitride indenter opens wide possibilities for nanostructuring burnishing of hardened bearing steel. Firstly, a flat cylindrical indenter has high durability due to repeated rotation around its axis. Secondly, the change of the tilt angle to the treated surface allows controlling the contact compression pressure and plastic shear deformation, which determines the formation of a nanostructured state of the material by the method of severe plastic deformation (SPD). The purpose of the work is to determine the optimal parameters of the process and tool in order to form a nanostructure and significantly increase surface layer microhardness. The goal was achieved by the methods of finite element modeling (FEM) and experimental studies of burnishing when the indenter tilt angle changes from 0.5° to 2.5° under dry processing conditions. Numerical simulation of the process made it possible to establish optimal values of the indenter tilt angle of 2° and the burnishing force 250 N according to the criteria of maximum contact pressure and cumulative deformation. The experimental studies of cumulative deformations and the coefficient of friction by the method of burnishing a split disc and dynamometry of the process confirmed the FEM results. The transmission microscopy, durometry, and 3D surface profilometry showed the sensitivity of nanocrystallite sizes, microhardness, and roughness to an indenter tilt angle and confirmed the optimality of the established tilt angle value. [ABSTRACT FROM AUTHOR]

[Ca2+]-dependent crystallization of the Ca2+-ATPase molecules in sarcoplasmic reticulum (SR) vesicles isolated from scallop striated muscle elongated the vesicles in the absence of ATP, and ATP stabilized the crystals. Here, to determine the [Ca2+]-dependence of vesicle elongation in the presence of ATP, SR vesicles in various [Ca2+] environments were imaged using negative stain electron microscopy. The images obtained revealed the following phenomena. (i) Crystal-containing elongated vesicles appeared at ≤1.4 µM Ca2+ and almost disappeared at ≥18 µM Ca2+, where ATPase activity reaches its maximum. (ii) At ≥18 µM Ca2+, almost all SR vesicles were in the round form and covered by tightly clustered ATPase crystal patches. (iii) Round vesicles dried on electron microscopy grids occasionally had cracks, probably because surface tension crushed the solid three-dimensional spheres. (iv) [Ca2+]-dependent ATPase crystallization was rapid (<1 min) and reversible. These data prompt the hypothesis that SR vesicles autonomously elongate or contract with the help of a calcium-sensitive ATPase network/endoskeleton and that ATPase crystallization may modulate physical properties of the SR architecture, including the ryanodine receptors that control muscle contraction. [ABSTRACT FROM AUTHOR]

Waste Cooking Oils (WCOs) are generated worldwide through industrial food processing and household use, posing environmental concerns upon disposal. Bentonites often showed to be effective in removing minor contaminants in vegetable oil refining. The present research focused on the processing of raw WCOs using four bentonites, two commercials and two obtained by ball milling of the latest. The different bentonites (hydrophobic and hydrophilic) were characterized before and after ball milling (BM) procedure, including an exhaustive analyses of crystal structure, morphology and surface area via x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and N 2 -physisorption technique. Optimization of BM processing in terms of milling time was achieved within 60 min. The milled powders were then tested as adsorbents for recycling WCOs with different degrees of decomposition (expressed in terms of free fatty acids, FFAs, content). Employing a design of experiments approach, the impact of five parameters (FFAs content, temperature, specific surface area, stirring, BM time) on the resulting pour point (PP), taken as a quality benchmark for recycled oil, was assessed. Quantitative multivariate statistical analysis revealed temperature's negligible role and identified the significant impact of two characteristics of the bentonite (specific superficial area and ball milling time), as well as the relevant role of the stirring during the treatment. At the end, hydrophilic bentonite resulted able to improve the PP of waste oils with a low content of free fatty acids of about 10 °C. [Display omitted] • Hydrophobicity of bentonites is a pivotal parameter in waste cooking oil recycling • It is possible to improve the recycling outcome of waste cooking oil with bentonite by ball milling pre-treatment • Refining of waste cooking oils with bentonite is not temperature-depending • Pour point of recycled vegetable oils can be consistently improved by choosing the proper bentonite and condition [ABSTRACT FROM AUTHOR]

There is a possibility this illustrates electron diffraction through the (1 1 2) diagonal direction in of the tetragonal crystal structure of Bismoclite.  I also think it looks neat.

We improved the three‐dimensional spatial resolution of laser scanning transmission microscopy by exploiting the saturated absorption of dye molecules. The saturated absorption is induced by the high‐intensity light irradiation and localises the signal within the centre of the focal spot. Our numerical calculation indicates that the spatial resolution in transmission imaging is significantly improved for both lateral and axial directions using nonlinear transmitted signals induced by saturated absorption. We experimentally demonstrated the improvement of the three‐dimensional resolution by observing fine structures of stained rat kidney tissues, which were not able to be visualised by conventional laser scanning transmission microscopy. [ABSTRACT FROM AUTHOR]

The Ca2+-ATPase is an integral transmembrane Ca2+ pump of the sarcoplasmic reticulum (SR). Crystallization of the cytoplasmic surface ATPase molecules of isolated scallop SR vesicles was studied at various calcium concentrations by negative stain electron microscopy. In the absence of ATP, round SR vesicles displaying an assembly of small crystalline patches of ATPase molecules were observed at 18 µM [Ca2+]. These partly transformed into tightly elongated vesicles containing ATPase crystalline arrays at low [Ca2+] (≤1.3 µM). The arrays were classified as ''tetramer", "two-rail" (like a railroad) and ''monomer". Their crystallinity was low, and they were unstable. In the presence of ATP (5 mM) at a low [Ca2+] of ~0.002 µM, "two-rail" arrays of high crystallinity appeared more frequently in the tightly elongated vesicles and the distinct tetramer arrays disappeared. During prolonged (~2.5 h) incubation, ATP was consumed and tetramer arrays reappeared. A specific ATPase inhibitor, thapsigargin, prevented both crystal formation and vesicle elongation in the presence of ATP. Together with the second part of this study, these data suggest that the ATPase forms tetramer units and longer tetramer crystalline arrays to elongate SR vesicles, and that the arrays transform into more stable "two-rail" forms in the presence of ATP at low [Ca2+]. [ABSTRACT FROM AUTHOR]

The paper is dedicated to investigation of the influence of rapid thermal treatment on the microstructure of platinum silicide. The Pt films 43.7 nm thick were applied on the substrates of the monocrystal silicon by means of the magnetronic sputtering of platinum with the purity of 99.95 % on the МРС 603 set-up with the cryogenic pumping to the pressure not worse than 5*10-5 Pa. As an operating medium, argon was used with the purity of 99.933 %. Rapid thermal treatment of samples was performed in the thermal balance conditions by irradiating the non-working side of the wafer with the incoherent light flow in the nitrogen atmosphere during 7 s at the temperatures of 200-550 °C. The irradiation source in the set-up was represented by the quartz halogen incandescent lamps. The comparative analysis was done through the traditional long thermal treatment of the platinum films at a temperature of 550оС for 30 min in the nitrogen atmosphere. Investigations of the platinum silicide microstructure were performed by means of the transmission electron microscopy which demonstrated that the increase in the RTT temperature initiates first the annealing of defects on the inter-grain boundaries, which is evident from the more distinct contrast from the grains, and then one can observe their growth reflecting the forming of the new phase (silicide one). Such progress of changes of the platinum silicide microstructure and of the size of the grains with the increase in treatment temperature is determined by the heat of its forming. As the Pt2Si phase forming heat is minimum and constitutes 10.4-16.8 Kkal/atom of metal, and for PtSi - 15.7-25.5 Kkal/atom of metal, then the forming of a stable PtSi structure requires a higher temperature. The authors carried out calculations of the activation energy of the diffusion synthesis of platinum silicide during rapid thermal treatment. The calculations show that it is 0.37 eV smaller, than during the long thermal treatment. This means that in this case this process is subject to acceleration related to the rupture of the silicon-silicon bonds and electron excitation in silicon under the influence of the photon flow.

Summary: There are two light microscopic methods for cell volume measurement based on volume exclusion. One method, sometimes referred to as FLEX, utilises negative staining by an external fluorescent dye, and cell volume is found from attenuation of fluorescence under a wide‐field microscope. The other method (TTD) is based on exclusion of an external absorbing dye, resulting in an increased intensity of transmission image. In this work, we compared these two methods. TTD measurements were consistent, reproducible and identical to those obtained by confocal scanning. In our hands, FLEX based on either sodium fluorescein of fluorescent dextran, usually resulted in underestimation of cell volume, which were insignificant in shallow chambers but became more severe with increased chamber depth. We have not been able to exactly pinpoint the source of the problem; it may have been undetected accumulation of dye in the cells or, more likely, some unappreciated aspects of image formation under epi‐illumination. We also discuss applicability of both methods to in‐flow volume measurements. Lay Description: Cell volume is a parameter important for many cell biological and physiological applications, and many different methods have been proposed for its measurement. Two light microscopic methods based on volume exclusion deserve special attention due to their speed and simplicity. In one of them (transmission‐through‐dye, or TTD), cells are placed in a shallow chamber, and a strongly absorbing external dye is added to the cell‐containing medium. The sample is imaged in transmission at a wavelength of maximum dye absorption. Because cells with intact membranes exclude the dye, they appear brighter on a transmission image, and their contrast quantitatively reflects cell thickness. By summation of thickness values over the cell area, cell volume can be obtained. The other method sometimes referred to as FLEX utilises exclusion of a fluorescent dye. Cells appear darker than the background under wide‐field fluorescence observation in accordance with their thicknesses, and cell volume is computed by thickness summation over the area, like in TTD. In this work, we compared the accuracy of TTD and FLEX for volume measurements. TTD and confocal scanning produced virtually identical results, which suggests that TTD data are accurate. On the other hand, cell volumes measured by FLEX were consistently smaller than by TTD. The discrepancy always increased with the depth of the chamber, although the exact relationship varied between experiments. By contrast, TTD results were insensitive to chamber depth. Thus, it appears that FLEX underestimates cell volume. The reason for that is not entirely clear. Accumulation of the fluorescent dye inside the cell could be a possibility, although we found no evidence for that. Most likely, the reason lies with some unappreciated aspects of wide‐field fluorescence image formation, which has not been well‐characterised for the type of negative staining used in FLEX. In our opinion, TTD is the method of choice, at least for stationary cells. On the other hand, due to linear dependence of intensity on volume, FLEX might offer advantages for high‐throughput flow volume imaging, although realisation of such an experiment has yet to be worked out. [ABSTRACT FROM AUTHOR]

In this report, we present transfer-free p-type hydrogen-intercalated quasi-free-standing epitaxial Chemical Vapor Deposition graphene on 15-mm × 15-mm semi-insulating vanadium-compensated on-axis 6H SiC(0001), characterized in that its room-temperature direct-current Hall-effect-derived hole mobility μ p = 5019 cm2/Vs, and its statistical number of layers (N), as indicated by the relative intensity of the SiC-related Raman-active longitudinal optical A 1 mode at 964 cm−1, equals N = 1.05. The distribution of the ellipsometric angle Ψ measured at an angle of incidence of 50 ° and λ = 490 nm points out to N = 0.97. The close-to-unity value of N implies that the material under study is a close-to-perfect quasi-free-standing monolayer, which is further confirmed by High-Resolution Transmission Electron Microscopy. Therefore, its spectroscopic properties, which include the Si H peak at 2131 cm−1, the histograms of Ψ and Δ , and the Raman G and 2D band positions, widths, and the 2D-to-G band intensity ratios, constitute a valuable reference for this class of materials. • Quasi-free-standing single-layer graphene in an industrial technology • Direct observation of the hydrogen-related Si-H peak at 2131 cm-1 • Parameters for effective ellipsometric characterization of QFS graphene on SiC • Referential database of graphene spectroscopic properties • Novel approach to graphene certification [Display omitted] [ABSTRACT FROM AUTHOR]

Molybdenum sulfide MoS 2 slabs length L and stacking S obtained from the transmission microscopy (TEM) images are the major characteristics of hydrotreating sulfide catalysts, widely used as morphology descriptors. In this work we demonstrate that the formulae routinely used to estimate mean L and S should be revisited. To obtain physically meaningful values L and S, both should be calculated as surface weighted averages. Moreover, correlation between L and S must be taken into account. Using surface weighted values of mean L and S, MoS 2 phase morphology was studied for a series of MoS 2 /Al 2 O 3 catalysts. The effects of Mo loading, addition of citric acid and sulfidation by H 2 S/N 2 or H 2 S/H 2 mixtures at different temperatures from 350 to 550 °C were studied. The catalysts were evaluated in hydrodesulfurization of thiophene (HDS) and studied by temperature programmed reduction (TPR). Thorough statistical treatment of TEM, HDS and TPR data suggests that the intrinsic properties of MoS 2 active phase depend primarily on the treatment atmosphere and temperature rather than on the addition of citric acid. If the impregnated catalyst is dried at temperature above 120 °C, citric acid allows moderate improvement of MoS 2 morphology. However the edge-specific activity of supported sulfide remains unaffected. [ABSTRACT FROM AUTHOR]

The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH), which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an innovative approach to the subject. [ABSTRACT FROM AUTHOR]

Spore accumulation in Brevibacillus laterosporus in a liquid nutrient medium under optimal conditions during stationary cultivation was investigated. The structure of floating biofilms was studied by transmission and scanning electron microscopy. It was shown that B. laterosprus cells formed a biofilm within 96 h of incubation. The accumulation of spores and individual vegetative cells in the biofilm was confirmed by light microscopy. The spore ultrastructure was shown to depend on the richness of the media. As was shown for the first time, B. laterosprus had an unusual morphology when grown in a yeast polysaccharide medium. A difference between B. laterosprus and Bacillus subtilis biofilms concerning the vegetative cells and spores was observed. In B. subtilis biofilm, the vegetative cells are numerous and devoid of the defects that are characteristic of B. laterosprus. The results may be helpful in optimizing bacilli-based biotechnological processes aimed at improving the yield of target products. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of neem extract (Azadirachta indica A. Juss) on the ultrastructure of the rat oral epithelium, because neem extract has been added in the tooth paste as an anti-plaqueforming substance in Asian countries. The non-toxic dose of 2000 mg/kg body weight of Neem extract (NBE) was applied daily to the surface of buccal epithelium for four weeks and controls did not receive Neem extract. After four weeks cheek epithelial tissues were excised and processed for light microscopy, scanning and transmission electron microscopy. Light microscopy did not show significant differences between NBE-treated and control epithelium. Difference between control and treated rats weight was non-significant. Moreover, time period was also non-significant. Irregular cell surfaces were noticed when compared to control specimens when examined by scanning electron microscopy. Under transmission electron microscopy, wider intercellular spaces were observed in the treated epithelial spinous cellular layers when compared to control. Further, more keratohyalin granules were present in experimental granular cells. It was concluded that present study showed differences between Neem-treated and control in epithelial tissues but these structural differences may not be related to adverse side effects of the Neem extract. [ABSTRACT FROM AUTHOR]

We have shown that use of the Tl 3 PbCl 5 nanocrystallites leads to the occurrence of a substantial increase of the SHG induced by the coherent doubled frequency light. We have found that for the fundamental microsecond 10.6 μm wavelengths, there exists a possibility to increase the SHG during illumination at 5.3 μm wavelength. The detailed analysis of the IR induced SHG has shown that the nanocrysatalline interfaces play here the principal role. Another important factor is the contribution of the phonon subsystem due to the presence of the IR stimulated anharmonic phonons. These results are compared with those of bulk crystals. [ABSTRACT FROM AUTHOR]

In situ transmission electron microscopy (TEM) nanomechanical testing has benefited from a number of recent technical developments related to both how deformation is imaged and how deformation is induced and measured inside a TEM instrument. These developments have led to new insights into the deformation mechanisms of a wide range of metals and alloys, as well as measurements of the unusual mechanical properties of small-scale objects such as whiskers and nanocrystals. Herein, we describe this recent progress through selected highlights of recent findings on the dynamic behavior of defects such as dislocations, twins, and grain boundaries. [ABSTRACT FROM AUTHOR]

The isothermal crystallization kinetics and morphology of poly(ethylene terephthalate) (PET) polymers of different molecular weights have been studied by means of differential scanning calorimetry and transmission microscopy (TM). The kinetic parameters of Avrami exponent n, the rate constant k, half time t, rate at 50 % crystallinity, τ for crystallization of different PETs were evaluated from double logarithmic plots of log {−ln[1 − X( t)]} versus log t, where X( t) is extent of crystallinity at a given crystallization temperature. The crystallization rate of polymers with high molecular weight found to be lower than that of polymers with low molecular weight, at the same crystallization temperature. It was found that the nucleation mechanism and growth dimension of polymers with low molecular weight are different from those of polymers with high molecular weight. The results of TM and isothermal crystallization kinetics showed a consistent trend for the crystallization of all PET polymers studied, comprising a primary stage and a secondary stage. The activation energy in the PET polymers of low molecular weight was found to be lower than that of polymers with high molecular weight. [ABSTRACT FROM AUTHOR]

An image-processing pipeline for the automated segmentation of yeast cells in microscopy images is proposed. The method is suitable for the non-invasive detection of individual cells in transmission data which can be acquired simultaneously with fluorescence data. It moreover takes the varying quality and highly heterogeneous characteristics of cells in transmission images into account, is capable to process images with dense yeast populations and can be used to extract quantitative cell-based data from transmission/fluorescence image pairs. Applicability and performance of the method is evaluated on a data set of 523 different yeast deletion mutant strains. [ABSTRACT FROM AUTHOR]

Abstract: Analysis of images from live-cell experiments is a central activity to studying the effects of stimulation on neuronal behavior. Image analysis techniques currently used to study these effects rely for the most part on the salience of the neuronal structures within the image. In both fluorescent and electron microscopy, neuronal structures are enhanced and therefore easy to distinguish in an image. Unlike images obtained via fluorescent or electron microscopy, however, images produced via transmission microscopy (e.g., bright field, phase contrast, DIC) are significantly more difficult to analyze because there is little contrast between the object-of-interest and the image background. This difficulty is amplified when a time-dependent sequence of images are to be analyzed, because of the corresponding large data sets. To address this problem, we introduce a novel approach to the analysis of images of live cells captured via transmission microscopy that takes advantage of commercially available software and the Fourier transform. Specifically, our approach utilizes several morphological functions in MATLAB to enhance the contrast of the cells with respect to the background, which is followed by 2-D Fourier analysis to generate a spectrum from which the orientation and alignment of cells and their processes can be measured. We show that this method can be used to simplify the interpretation of complex structure in images of live neurons obtained via transmission microscopy and consequently, discover trends in neurite development following different types of stimulation. This approach provides a consistent and reliable tool for analyzing changes in cell structure that occurs during live-cell experiments. [Copyright &y& Elsevier]

Abstract: As-received magnesium hydride (MgH2), and MgH2 doped with lithium borohydride (LiBH4) and titanium (III) chloride (TiCl3) catalyst were heated –in situ – in an environmental scanning electron microscope (ESEM) and a transmission electron microscope (TEM). Morphological and structural changes during heating and hydrogen desorption were recorded in real time. The studies show that native MgH2 undergoes dramatic and destructive structural changes upon heating, whereas the doped/catalyzed MgH2 mixture showed a benign outgassing with little structural change. Videos of the morphological changes during heating can be viewed online at the McGrady group website: http://www.unb.ca/fredericton/science/chem/smcgrady/group/shanebeattie/InsituESEMandTEM-MgH2.html. [Copyright &y& Elsevier]

Abstract: Energy filtered transmission electron microscopy (EFTEM), dark field imaging and light microscopy are well established methods to evaluate size, volume fraction and number density of precipitates on different size scales. The stereological problems are well known and analogous for all methods. Many evaluation methods can be found in literature, each of them valid for special sample geometries or special size distributions. Despite this variety, serious errors can occur if the assumptions do not exactly represent the real situation. In this paper, available and newly developed correction methods are tested for evaluating these parameters for different precipitate size distributions in a sample of arbitrary topography. It is shown that the newly proposed methods produce significantly lower deviations and are more assessable regarding their systematic errors. [Copyright &y& Elsevier]

A derivative of polythiophiene: poly(3-dodecylthiophene) (PT 12) has been used to fill electrochemically a porous silicon matrix. The composite, obtained by this way, should have a high third order nonlinear optical coefficient and good mechanical properties. SEM and TEM micrographs were taken after matrix dissolution in NaOH. Columns of polymer with the matrix pore shape show up like fingers. In consideration of the homogeneous filling profile of PT 12 measured by EDX and XPS and the low amount of polymer, we are probably dealing with tubes instead of wires. [Copyright &y& Elsevier]