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1
Chen, Xiaodong, Bin Zheng, and Hong Liu. "Optical and Digital Microscopic Imaging Techniques and Applications in Pathology." Analytical Cellular Pathology 34, no. 1-2 (2011): 5–18. http://dx.doi.org/10.1155/2011/150563.
Повний текст джерелаАнотація:
The conventional optical microscope has been the primary tool in assisting pathological examinations. The modern digital pathology combines the power of microscopy, electronic detection, and computerized analysis. It enables cellular-, molecular-, and genetic-imaging at high efficiency and accuracy to facilitate clinical screening and diagnosis. This paper first reviews the fundamental concepts of microscopic imaging and introduces the technical features and associated clinical applications of optical microscopes, electron microscopes, scanning tunnel microscopes, and fluorescence microscopes. The interface of microscopy with digital image acquisition methods is discussed. The recent developments and future perspectives of contemporary microscopic imaging techniques such as three-dimensional and in vivo imaging are analyzed for their clinical potentials.
2
Daberkow, I., and M. Schierjott. "Possibilities And Examples For Remote Microscopy Including Digital Image Acquisition, Transfer, and Archiving." Microscopy and Microanalysis 4, S2 (July 1998): 2–3. http://dx.doi.org/10.1017/s1431927600020134.
Повний текст джерелаАнотація:
Recent developments promise the possibility to externally control every aspect of microscopes through a computer interface. In combination with high-resolution cameras and feedback to the microscope, this can be leveraged to create highly automatic routines, e.g., to remotely correct astigmatism. Together with the development of fast computer networks this creates a new branch of microscopy, the so-called “telemicroscopy”. The goal of telemicroscopy is the control of a microscope over a large distance including the transfer of images with an acceptable repetition rate. A big advantage for electron microscopy in particular is the possibility of having access to expensive and well-equipped microscopes. In the field of light microscopy the branch “telemedicine” was created, meaning the “virtual” presence of a colleague or specialist for discussion or diagnosis.Using transmission electron microscopy as an example, the history and special requirements for automation and telemicroscopy will be discussed. In the late 80's the first TEM with a remote control was revealed. Shortly thereafter, first automatic functions for defocus control and astigmatism correction were developed using a video camera as electronic image converter.
3
Liu, J., and J. R. Ebner. "Nano-Characterization of Industrial Heterogeneous Catalysts." Microscopy and Microanalysis 4, S2 (July 1998): 740–41. http://dx.doi.org/10.1017/s1431927600023825.
Повний текст джерелаАнотація:
Catalyst characterization plays a vital role in new catalyst development and in troubleshooting of commercially catalyzed processes. The ultimate goal of catalyst characterization is to understand the structure-property relationships associated with the active components and supports. Among many characterization techniques, only electron microscopy and associated analytical techniques can provide local information about the structure, chemistry, morphology, and electronic properties of industrial heterogeneous catalysts. Three types of electron microscopes are usually used for characterizing industrial supported catalysts: 1) scanning electron microscope (SEM), 2) scanning transmission electron microscope (STEM), and 3) transmission electron microscope (TEM). Each type of microscope has its unique capabilities. However, the integration of all electron microscopic techniques has proved invaluable for extracting useful information about the structure and the performance of industrial catalysts.Commercial catalysts usually have a high surface area with complex geometric structures to enable reacting gases or fluids to access as much of the active surface of the catalyst as possible.
4
Kordesch, Martin E. "Introduction to emission electron microscopy for the in situ study of surfaces." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 506–7. http://dx.doi.org/10.1017/s0424820100148368.
Повний текст джерелаАнотація:
The Photoelectron Emission Microscope (PEEM) and Low Energy Electron Microscope (LEEM) are parallel-imaging electron microscopes with highly surface-sensitive image contrast mechanisms. In PEEM, the electron yield at the illumination wavelength determines image contrast, in LEEM, the intensity of low energy (< 100 eV) electrons back-diffracted from the surface, as well as interference effects, are responsible for image contrast. Mirror Electron Microscopy is also possible with the LEEM apparatus. In MEM, no electron penetration into the solid occurs, and an image of surface electronic potentials is obtained.While the emission microscope techniques named above are not high resolution methods, the unique contrast mechanisms, the ability to use thick single crystal samples, their compatibility with uhv surface science methods and new material-growth methods, coupled with real-time imaging capability, make them very useful.These microscopes do not depend on scanning probes, and some are compatible with pressures up to 10-3 Torr and specimen temperatures above 1300K.
5
Vilà, Anna, Sergio Moreno, Joan Canals, and Angel Diéguez. "A Compact Raster Lensless Microscope Based on a Microdisplay." Sensors 21, no. 17 (September 3, 2021): 5941. http://dx.doi.org/10.3390/s21175941.
Повний текст джерелаАнотація:
Lensless microscopy requires the simplest possible configuration, as it uses only a light source, the sample and an image sensor. The smallest practical microscope is demonstrated here. In contrast to standard lensless microscopy, the object is located near the lighting source. Raster optical microscopy is applied by using a single-pixel detector and a microdisplay. Maximum resolution relies on reduced LED size and the position of the sample respect the microdisplay. Contrarily to other sort of digital lensless holographic microscopes, light backpropagation is not required to reconstruct the images of the sample. In a mm-high microscope, resolutions down to 800 nm have been demonstrated even when measuring with detectors as large as 138 μm × 138 μm, with field of view given by the display size. Dedicated technology would shorten measuring time.
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Kondo, Y., K. Yagi, K. Kobayashi, H. Kobayashi, and Y. Yanaka. "Construction Of UHV-REM-PEEM for Surface Studies." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 350–51. http://dx.doi.org/10.1017/s0424820100180501.
Повний текст джерелаАнотація:
Recent development of ultra-high vacuum electron microscopy (UHV-EM) is very rapid. This is due to the fact that it can be applied to variety of surface science fields.There are various types of surface imaging in UHV condition; low energy electron microscopy (LEEM) [1], transmission (TEM) and reflection electron microscopy (REM) [2] using conventional transmission electron microscopes (CTEM) (including scanning TEM and REM)), scanning electron microscopy, photoemission electron microscopy (PEEM) [3] and scanning tunneling microscopy (STM including related techniques such as scanning tunneling spectroscopy (STS), atom force microscopy and magnetic force microscopy)[4]. These methods can be classified roughly into two; in one group image contrast is mainly determined by surface atomic structure and in the other it is determined by surface electronic structure. Information obtained by two groups of surface microscopy is complementary with each other. A combination of the two methods may give images of surface crystallography and surface electronic structure. STM-STS[4] and LEEM-PEEM [3] so far developed are typical examples.In the present work a combination of REM(TEM) and PEEM (Fig. 1) was planned with use of a UHV CTEM. Several new designs were made for the new microscope.
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Katoh, Kazuo. "Software-Based Three-Dimensional Deconvolution Microscopy of Cytoskeletal Proteins in Cultured Fibroblast Using Open-Source Software and Open Hardware." Journal of Imaging 5, no. 12 (November 23, 2019): 88. http://dx.doi.org/10.3390/jimaging5120088.
Повний текст джерелаАнотація:
As conventional fluorescence microscopy and confocal laser scanning microscopy generally produce images with blurring at the upper and lower planes along the z-axis due to non-focal plane image information, the observation of biological images requires “deconvolution.” Therefore, a microscope system’s individual blur function (point spread function) is determined theoretically or by actual measurement of microbeads and processed mathematically to reduce noise and eliminate blurring as much as possible. Here the author describes the use of open-source software and open hardware design to build a deconvolution microscope at low cost, using readily available software and hardware. The advantage of this method is its cost-effectiveness and ability to construct a microscope system using commercially available optical components and open-source software. Although this system does not utilize expensive equipment, such as confocal and total internal reflection fluorescence microscopes, decent images can be obtained even without previous experience in electronics and optics.
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Schwarzer, Robert. "Orientation Microscopy Using the Analytical Scanning Electron Microscope." Practical Metallography 51, no. 3 (March 17, 2014): 160–79. http://dx.doi.org/10.3139/147.110280.
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Dantas de Oliveira, Allisson, Carles Rubio Maturana, Francesc Zarzuela Serrat, Bruno Motta Carvalho, Elena Sulleiro, Clara Prats, Anna Veiga, et al. "Development of a low-cost robotized 3D-prototype for automated optical microscopy diagnosis: An open-source system." PLOS ONE 19, no. 6 (June 21, 2024): e0304085. http://dx.doi.org/10.1371/journal.pone.0304085.
Повний текст джерелаАнотація:
In a clinical context, conventional optical microscopy is commonly used for the visualization of biological samples for diagnosis. However, the availability of molecular techniques and rapid diagnostic tests are reducing the use of conventional microscopy, and consequently the number of experienced professionals starts to decrease. Moreover, the continuous visualization during long periods of time through an optical microscope could affect the final diagnosis results due to induced human errors and fatigue. Therefore, microscopy automation is a challenge to be achieved and address this problem. The aim of the study is to develop a low-cost automated system for the visualization of microbiological/parasitological samples by using a conventional optical microscope, and specially designed for its implementation in resource-poor settings laboratories. A 3D-prototype to automate the majority of conventional optical microscopes was designed. Pieces were built with 3D-printing technology and polylactic acid biodegradable material with Tinkercad/Ultimaker Cura 5.1 slicing softwares. The system’s components were divided into three subgroups: microscope stage pieces, storage/autofocus-pieces, and smartphone pieces. The prototype is based on servo motors, controlled by Arduino open-source electronic platform, to emulate the X-Y and auto-focus (Z) movements of the microscope. An average time of 27.00 ± 2.58 seconds is required to auto-focus a single FoV. Auto-focus evaluation demonstrates a mean average maximum Laplacian value of 11.83 with tested images. The whole automation process is controlled by a smartphone device, which is responsible for acquiring images for further diagnosis via convolutional neural networks. The prototype is specially designed for resource-poor settings, where microscopy diagnosis is still a routine process. The coalescence between convolutional neural network predictive models and the automation of the movements of a conventional optical microscope confer the system a wide range of image-based diagnosis applications. The accessibility of the system could help improve diagnostics and provide new tools to laboratories worldwide.
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Faruqi, A. R., and Sriram Subramaniam. "CCD detectors in high-resolution biological electron microscopy." Quarterly Reviews of Biophysics 33, no. 1 (February 2000): 1–27. http://dx.doi.org/10.1017/s0033583500003577.
Повний текст джерелаАнотація:
1. Introduction 11.1 The ‘band gap’ in silicon 22. Principles of CCD detector operation 32.1 Direct detection 32.2 Electron energy conversion into light 42.3 Optical coupling: lens or fibre optics? 62.4 Readout speed and comparison with film 83. Practical considerations for electron microscopic applications 93.1 Sources of noise 93.1.1 Dark current noise 93.1.2 Readout noise 93.1.3 Spurious events due to X-rays or cosmic rays 103.2 Efficiency of detection 113.3 Spatial resolution and modulation transfer function 123.4 Interface to electron microscope 143.5 Electron diffraction applications 154. Prospects for high-resolution imaging with CCD detectors 185. Alternative technologies for electronic detection 235.1 Image plates 235.2 Hybrid pixel detectors 246. References 26During the past decade charge-coupled device (CCD) detectors have increasingly become the preferred choice of medium for recording data in the electron microscope. The CCD detector itself can be likened to a new type of television camera with superior properties, which makes it an ideal detector for recording very low exposure images. The success of CCD detectors for electron microscopy, however, also relies on a number of other factors, which include its fast response, low noise electronics, the ease of interfacing them to the electron microscope, and the improvements in computing that have made possible the storage and processing of large images.CCD detectors have already begun to be routinely used in a number of important biological applications such as tomography of cellular organelles (reviewed by Baumeister, 1999), where the resolution requirements are relatively modest. However, in most high- resolution microscopic applications, especially where the goal of the microscopy is to obtain structural information at near-atomic resolution, photographic film has continued to remain the medium of choice. With the increasing interest and demand for high-throughput structure determination of important macromolecular assemblies, it is clearly important to have tools for electronic data collection that bypass the slow and tedious process of processing images recorded on photographic film.In this review, we present an analysis of the potential of CCD-based detectors to fully replace photographic film for high-resolution electron crystallographic applications.
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Bornhorst, Julia, Eike Nustede, and Sebastian Fudickar. "Mass Surveilance of C. elegans—Smartphone-Based DIY Microscope and Machine-Learning-Based Approach for Worm Detection." Sensors 19, no. 6 (March 26, 2019): 1468. http://dx.doi.org/10.3390/s19061468.
Повний текст джерелаАнотація:
The nematode Caenorhabditis elegans (C. elegans) is often used as an alternative animal model due to several advantages such as morphological changes that can be seen directly under a microscope. Limitations of the model include the usage of expensive and cumbersome microscopes, and restrictions of the comprehensive use of C. elegans for toxicological trials. With the general applicability of the detection of C. elegans from microscope images via machine learning, as well as of smartphone-based microscopes, this article investigates the suitability of smartphone-based microscopy to detect C. elegans in a complete Petri dish. Thereby, the article introduces a smartphone-based microscope (including optics, lighting, and housing) for monitoring C. elegans and the corresponding classification via a trained Histogram of Oriented Gradients (HOG) feature-based Support Vector Machine for the automatic detection of C. elegans. Evaluation showed classification sensitivity of 0.90 and specificity of 0.85, and thereby confirms the general practicability of the chosen approach.
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Paci, G., E. Haas, L. Kornau, D. Marchetti, L. Wang, R. Prevedel, and A. Szmolenszky. "Microscope in Action: An Interdisciplinary Fluorescence Microscopy Hands-on Resource for Schools." Biophysicist 2, no. 3 (October 7, 2021): 55–73. http://dx.doi.org/10.35459/tbp.2020.000171.
Повний текст джерелаАнотація:
ABSTRACT Fluorescence microscopy is a ubiquitous technique in the life sciences that uses fluorescent molecules to visualize specific components of biological specimens. This powerful tool has revolutionized biology, and it represents a perfect example of the advancements enabled by biophysical research and technology development. However, despite its central role in contemporary research, fluorescence is hardly covered in typical secondary school curricula, with few hands-on “entry-level” materials available for secondary school teachers to introduce this important method to their students. Furthermore, most commercially available fluorescence microscopes are prohibitively costly and often appear as “black boxes.” To address this gap, we introduce here an experimental, research-grade fluorescence microscopy kit and educational resource targeted at secondary school students and teachers. Microscope in Action is an interdisciplinary resource based on active learning that combines concepts from both optics and biology. The students assemble a functional microscope from basic optical, mechanical, and electronic parts, thereby testing and understanding the function of each component “hands-on.” We also present sample preparation and imaging activities that can be incorporated to enable an exploration of biological topics with the assembled microscope and exercises in which students actively learn and practice scientific thinking by collecting and analyzing data. Although the resource was developed with secondary schools in mind, the variety of available protocols and the adjustable module lengths make it suitable for different age groups and topics, from middle school to PhD level, from short workshops to courses spanning several days.
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Inoué, Shinya. "Digitally Enhanced, Polarization-Based Microscopy: Reality and Dreams." Microscopy and Microanalysis 7, S2 (August 2001): 2–3. http://dx.doi.org/10.1017/s1431927600026088.
Повний текст джерелаАнотація:
Polarized light microscopy is used to identify and image optically anisotropic regions of the specimen; to determine their optical character; and to explore the arrangement of the molecules, fine structure, or atomic lattices that are responsible for the anisotropy. These studies can be carried out non-destructively in real time, and reveal events or structures that lie far below the resolution limit of the light microscope, or indeed at times even the electron microscope.In biology, to study the dynamically changing, minute and weakly anisotropic domains within living cells, the polarizing microscope must be able to detect and measure birefringence retardances to a fraction of a nm, record the image with high microscopic resolution at nearvideo rate, and do so while the cell remains active.Over the years, the extinction property and imaging capability of the basic polarizing microscope have been substantially improved by advances in optical design. More recently, video and CCD imaging and digital electronic processing have further enhanced the quality of the polarizing microscope image and our ability to rapidly detect and measure weak anisotropy.
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Abe, Eiji. "Electron Microscopy for Atomic/Electronic Structure of Quasicrystals." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1193. http://dx.doi.org/10.1107/s2053273314088068.
Повний текст джерелаАнотація:
As stated with special emphasis in the Noble Lecture by Dr. Shechtman, the quasicrystal discovery is definitely the victory of electron microscopy – the first icosahedral stereogram was constructed by a series of electron diffraction patterns from a tiny quasicrystalline grain, and the following high-resolution electron microscope images indeed confirmed a unique aperiodic order that can never be consistent with twinning of normal crystals. Almost thirty years after these early electron microscopy studies, we are now in the era of aberration-corrected electron microscopy which realizes a remarkable resolution beyond an Ångstrom scale [1, 2]. In the talk, I will describe the local atomic/electronic structure of quasicrystals using state-of-the-art scanning transmission electron microscopy, providing several striking insights that may lead to the answers for the longstanding key questions; "Where are the atoms? And why do quasicrystals form?"
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Erickson, A., D. Adderton, T. Day, and R. Alvis. "Imaging free Carriers in Electronic Material using a Scanning Probe Microscope: Scanning Capacitance Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 956–57. http://dx.doi.org/10.1017/s042482010016724x.
Повний текст джерелаАнотація:
The development of methods to measure electrical properties, which are suitable to directly yield the desired carrier distributions on a nanometer scale has greatly benefited from the development of scanning probe technology over the last decade. Scanning Probe Microscopes (SPMs) offer inherent two-dimensionality and have been shown to have applications ranging from Magnet force to electro-chemistry. We have used an SPM in contact mode to simultaneously measure topography (and therefore physical structure) and capacitance variations (due to an applied bias) of various electronic materials such asdoped silicon, poly silicon, SiC, and III-V materials.The technique aptly named Scanning Capacitance Microscopy (SCM) takes advantage of the fact that electrical carrier response to an applied electric field is largely dependent upon the local carrier concentration. Using a high 'Q' GHz resonant circuit, SCM measures capacitance variations due to an applied bias between the metalized nano-probe tip and semiconductor sample during scanning. Since thesevariations are directly related to dopant (carrier) concentration, the SCM generates a two-dimensional image with contrast corresponding to near-surface variations in carrier density. Because the measurement is done with an extremely sharp probe, we have been able to resolve features as small as lOnm, corresponding to attofarad (le-18 farad) capacitance changes.
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Itoh, J., R. Y. Osamura, and K. Watanabe. "Subcellular visualization of light microscopic specimens by laser scanning microscopy and computer analysis: a new application of image analysis." Journal of Histochemistry & Cytochemistry 40, no. 7 (July 1992): 955–67. http://dx.doi.org/10.1177/40.7.1607644.
Повний текст джерелаАнотація:
To identify subcellular organelles or to observe their pathological changes in sections prepared for light microscopy, immuno- and/or enzyme histochemical staining for the marker substances or enzymes of those subcellular organelles are frequently employed. With conventional light microscopes (CLM), however, it is hardly possible to determine whether or not the target organelles are properly stained and to confirm their fine structure. In the present study, the laser scanning microscope (LSM) was employed to obtain highly contrasted images of histochemically stained subcellular organelles at the limit of resolution in light microscopy. To refine or characterize those images, images built up as electronic signals in LSM were further processed in the Image Analysis System (IAS) with pipeline. Thus, the approximate figures of subcellular organelles such as microtubules, endoplasmic reticula, secretory granules, and mitochondria were visualized in brightfield on sections prepared for light microscopy (paraffin, frozen sections and cultured living cells). The validity of the images obtained by LSM or LSM-IAS was confirmed by immunoelectron microscopy when possible. The LSM images of histochemically stained suborganelles of various cells were definitely improved (refined and/or strengthened) by processing them with IAS.
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Hansen, Douglas. "The Scanning Electron Microscope As A Precision Instrument." Microscopy Today 4, no. 6 (August 1996): 30–34. http://dx.doi.org/10.1017/s1551929500060909.
Повний текст джерелаАнотація:
I began using scanning electron microscopes to solve problems encountered in the fabrication of x-ray diffraction gratings. Since these diffraction gratings consist of very regular lines and spaces, and produce high contrast images from the SEM. my microscopy work often points out problems with the microscope.One time, for example, I went to the university SEM lab I often use, and was advised that the microscope was down that day due to major field problems. This lab often had problems with stray fields for reasons no one could explain. Usually I was the only one to complain about stray field distortions since they are most obvious when imaging straight lines at high magnification, but on this occasion, the problem was serious and obvious to all.The microscope had just been serviced and as the lens coils had been replaced, they were expected to be the cause. The service technician was called in and determined that neither the coils nor the microscope electronics were the problem.
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Jones, Arthur V. "Novel Approaches to Low-Voltage Scanning Electron Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 366–67. http://dx.doi.org/10.1017/s0424820100180586.
Повний текст джерелаАнотація:
In comparison with the developers of other forms of instrumentation, scanning electron microscope manufacturers are among the most conservative of people. New concepts usually must wait many years before being exploited commercially. The field emission gun, developed by Albert Crewe and his coworkers in 1968 is only now becoming widely available in commercial instruments, while the innovative lens designs of Mulvey are still waiting to be commercially exploited. The associated electronics is still in general based on operating procedures which have changed little since the original microscopes of Oatley and his co-workers.The current interest in low-voltage scanning electron microscopy will, if sub-nanometer resolution is to be obtained in a useable instrument, lead to fundamental changes in the design of the electron optics. Perhaps this is an opportune time to consider other fundamental changes in scanning electron microscopy instrumentation.
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Canals, Joan, Nil Franch, Victor Moro, Sergio Moreno, Juan Prades, Albert Romano-Rodríguez, Steffen Bornemann, et al. "A Novel Approach for a Chip-Sized Scanning Optical Microscope." Micromachines 12, no. 5 (May 6, 2021): 527. http://dx.doi.org/10.3390/mi12050527.
Повний текст джерелаАнотація:
The recent advances in chip-size microscopy based on optical scanning with spatially resolved nano-illumination light sources are presented. This new straightforward technique takes advantage of the currently achieved miniaturization of LEDs in fully addressable arrays. These nano-LEDs are used to scan the sample with a resolution comparable to the LED sizes, giving rise to chip-sized scanning optical microscopes without mechanical parts or optical accessories. The operation principle and the potential of this new kind of microscope are analyzed through three different implementations of decreasing LED dimensions from 20 µm down to 200 nm.
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Suzuki, T., M. Kudo, Y. Sakai, and T. Ichinokawa. "Material Contrast of Scanning Electron and Ion Microscope Images of Metals." Microscopy Today 16, no. 1 (January 2008): 6–11. http://dx.doi.org/10.1017/s1551929500054250.
Повний текст джерелаАнотація:
The rapid technical development of FIM (Focused Ion Beam) technology has spawned an increase in spatial resolution capability in scanning ion microscopy (SIM) technology. Furthermore, FIM has been used for preparation of thin specimens in transmission electron microscopy and micro-fabrication of electronic devices in the semiconductor industry. Recently, a scanning ion microscope with a helium field ion source has been developed. Thus, the contrast formation of emission electron images in scanning ion microscopy has been the object of study for analyzing images of materials specimens, similar to the theory behind scanning electron microscope (SEM) contrast formation. Furthermore, whether the electron emission yield γ induced by ion impact is periodic or non-periodic as a function of Z2 (the atomic number of the target) has not been well studied in the low energy region from several keV to the several tens of keV values used in SIM.
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Moreno, Sergio, Joan Canals, Victor Moro, Nil Franch, Anna Vilà, Albert Romano-Rodriguez, Joan Daniel Prades, et al. "Pursuing the Diffraction Limit with Nano-LED Scanning Transmission Optical Microscopy." Sensors 21, no. 10 (May 11, 2021): 3305. http://dx.doi.org/10.3390/s21103305.
Повний текст джерелаАнотація:
Recent research into miniaturized illumination sources has prompted the development of alternative microscopy techniques. Although they are still being explored, emerging nano-light-emitting-diode (nano-LED) technologies show promise in approaching the optical resolution limit in a more feasible manner. This work presents the exploration of their capabilities with two different prototypes. In the first version, a resolution of less than 1 µm was shown thanks to a prototype based on an optically downscaled LED using an LED scanning transmission optical microscopy (STOM) technique. This research demonstrates how this technique can be used to improve STOM images by oversampling the acquisition. The second STOM-based microscope was fabricated with a 200 nm GaN LED. This demonstrates the possibilities for the miniaturization of on-chip-based microscopes.
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Novikov, Yu A. "Modern Scanning Electron Microscopy. 1. Secondary Electron Emission." Поверхность. Рентгеновские, синхротронные и нейтронные исследования, no. 5 (May 1, 2023): 80–94. http://dx.doi.org/10.31857/s102809602305014x.
Повний текст джерелаАнотація:
The development of modern technologies, including nanotechnology, is based on application of diagnostic methods of objects used in technologies processes. For this purpose most perspective are methods realized in a scanning electron microscope. Thus one of basic methods is the measurement of linear sizes of relief structures of micrometer and nanometer ranges used in micro- and nanoelectronic. In a basis of a scanning electron microscope job the secondary electronic issue of firm body lays. However, practically all researches were spent on surfaces, which relief was neglected. The review of theoretical and experimental materials to researches of a secondary electron emission is given. Practically all known laws are checked up in experiments and have received the physical explanation. However, the application of a secondary electronic emission in a scanning electron microscopy, used in micro- both nanoelectronic and nanotechnology, requires knowledge of laws, which are shown on relief surfaces. Is demonstrated, what laws can be applied in a scanning electron microscope to measurement of linear sizes of relief structures. Is judged necessity of an influence study of a surface relief on a secondary electron emission.
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WOOLARD, DWIGHT, PEIJI ZHAO, CHRISTOPHER RUTHERGLEN, ZHEN YU, PETER BURKE, STEVEN BRUECK, and ANDREAS STINTZ. "NANOSCALE IMAGING TECHNOLOGY FOR THz-FREQUENCY TRANSMISSION MICROSCOPY." International Journal of High Speed Electronics and Systems 18, no. 01 (March 2008): 205–22. http://dx.doi.org/10.1142/s012915640800528x.
Повний текст джерелаАнотація:
A novel nanoscale-engineering methodology is presented that has potential for the first-time development of a microscope-system capable of collecting terahertz (THz) frequency spectroscopic signatures from microscopic biological (bio) structures. This unique THz transmission microscopy approach is motivated by prior studies on bio-materials and bio-agents (e.g., DNA, RNA and bacterial spores) that have produced spectral features within the THz frequency regime (i.e., ~ 300 GHz to 1000 GHz) that appear to be representative of the internal structure and characteristics of the constituent bio-molecules. The suggested THz transmission microscopy is a fundamentally new technological approach that seeks to avoid the limitations that exist in traditional experiments (i.e., that must average over large numbers of microscopic molecules) by prescribing a viable technique whereby the THz frequency signatures may be collected from individual bio-molecules and/or microscopic biological constructs. Specifically, it is possible to envision the development of a “nanoscale imaging array” that possesses the characteristics necessary (e.g., sub-wavelength resolution) for successfully performing “THz-frequency microscopy.”
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Gómez-Rodríguez, J. M., and Baró A.M. "The use of Scanning Tunneling Microscopy in combination with Scanning Electron Microscopy in the fabrication and imaging of microstructures." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 4 (August 1990): 752–53. http://dx.doi.org/10.1017/s0424820100176897.
Повний текст джерелаАнотація:
In the last few years, Scanning Tunneling Microscopy (STM), has proven to be a powerful and versatile technique to investigate the topographic and electronic structure of metals and semiconductors with an unprecedent vertical (0.01 nm) and lateral (0.2 nm) resolution. In this paper we are interested in the use of STM to study surfaces having microfabricated structures in the nanometer range, particularly those produced by the STM tip itself.In order to study these samples we have used an STM integrated into a commercial Scanning Electron Microscope (SEM). This allows to address two problems which limit the operation of STM: (i) the limited STM scanning range (1-10 μm) which makes difficult the localization of microstructures on the sample; (ii) the undetermined size and shape of the STM probing tip.Our STM/SEM combination has been described in detail earlier. In short, it consists of an STM placed on the sample stage of a commercial SEM allowing the simultaneous operation of both microscopes.
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Mundschau, M., E. Bauer, and W. ᔒwięch. "Methods and Applications of UV Photoelectron Microscopy in Surface Science." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 564–65. http://dx.doi.org/10.1017/s0424820100181579.
Повний текст джерелаАнотація:
Photoelectron microscopy is sensitive to single atomic or molecular layers on surfaces at submonolayer coverages. A significant advance for fundamental studies in surface science has been the construction of ultra-high vacuum versions of classical photoelectron microscopes and the combination with other techniques of surface analysis - most notably low-energy electron diffraction and microscopy. This is essential for the proper interpretation of the micrographs. The technique is well suited for in situ studies of large flat samples such as silicon wafers, single crystals and polished metallurgical samples.One of the most promising fields for application of the photoelectron microscope is in the area of epitaxial growth.In epitaxy a crystalline substance grows as an oriented overgrowth atop a substrate. It has widespread use in the semiconductor industry and in the field of quantum electronics, in which epitaxially grown structures have the dimensions of the same order of magnitude as the wavelengths of the conducting electrons.
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Llavador, Anabel, Gabriele Scrofani, Genaro Saavedra, and Manuel Martinez-Corral. "Large Depth-of-Field Integral Microscopy by Use of a Liquid Lens." Sensors 18, no. 10 (October 10, 2018): 3383. http://dx.doi.org/10.3390/s18103383.
Повний текст джерелаАнотація:
Integral microscopy is a 3D imaging technique that permits the recording of spatial and angular information of microscopic samples. From this information it is possible to calculate a collection of orthographic views with full parallax and to refocus computationally, at will, through the 3D specimen. An important drawback of integral microscopy, especially when dealing with thick samples, is the limited depth of field (DOF) of the perspective views. This imposes a significant limitation on the depth range of computationally refocused images. To overcome this problem, we propose here a new method that is based on the insertion, at the pupil plane of the microscope objective, of an electrically controlled liquid lens (LL) whose optical power can be changed by simply tuning the voltage. This new apparatus has the advantage of controlling the axial position of the objective focal plane while keeping constant the essential parameters of the integral microscope, that is, the magnification, the numerical aperture and the amount of parallax. Thus, given a 3D sample, the new microscope can provide a stack of integral images with complementary depth ranges. The fusion of the set of refocused images permits to enlarge the reconstruction range, obtaining images in focus over the whole region.
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Lee, Dongwoo, Jihye Kim, Eunjoo Song, Ji-Young Jeong, Eun-chae Jeon, Pilhan Kim, and Wonhee Lee. "Micromirror-Embedded Coverslip Assembly for Bidirectional Microscopic Imaging." Micromachines 11, no. 6 (June 10, 2020): 582. http://dx.doi.org/10.3390/mi11060582.
Повний текст джерелаАнотація:
3D imaging of a biological sample provides information about cellular and subcellular structures that are important in cell biology and related diseases. However, most 3D imaging systems, such as confocal and tomographic microscopy systems, are complex and expensive. Here, we developed a quasi-3D imaging tool that is compatible with most conventional microscopes by integrating micromirrors and microchannel structures on coverslips to provide bidirectional imaging. Microfabricated micromirrors had a precisely 45° reflection angle and optically clean reflective surfaces with high reflectance over 95%. The micromirrors were embedded on coverslips that could be assembled as a microchannel structure. We demonstrated that this simple disposable device allows a conventional microscope to perform bidirectional imaging with simple control of a focal plane. Images of microbeads and cells under bright-field and fluorescent microscopy show that the device can provide a quick analysis of 3D information, such as 3D positions and subcellular structures.
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Fan, G. Y., and M. H. Ellisman. "Current State of the Art of Digital Imaging in TEM." Microscopy and Microanalysis 3, S2 (August 1997): 1087–88. http://dx.doi.org/10.1017/s1431927600012320.
Повний текст джерелаАнотація:
The increasingly wide use of digital computers, the world-wide-web and electronic publishing has had a fundamental impact on the way scientists conduct research in every discipline of science. Electron microscopy is no exception. A considerable amount of effort has been devoted to the development of digital imaging acquisition systems for transmission electron microscopy (TEM). Digital image acquisition systems for TEM, including complete systems, have been produced by several companies, including: Advanced Microscopy Techniques (Rowley, MA), JEOL (Peabody, MA), Gatan (Warrendale, PA), Princeton Instruments (Trenton, NJ) and Tietz-Video (Herbststrasse, Gauting, Germany). While most systems are CCD-based, JEOL has also offered a system which is based on the Imaging Plate technology.The Imaging Plate has the same size as, and is compatible with the camera system for, the 8.09 cm × 99.6 cm electron microscope film. As with film, a latent image is formed on the plate when exposed to electrons. A stack of exposed imaging plates are then taken out of the microscope and scanned by a laser beam in a readout device which converts the latent image to a digital form.
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Incardona, Nicolò, Ángel Tolosa, Gabriele Scrofani, Manuel Martinez-Corral, and Genaro Saavedra. "The Lightfield Microscope Eyepiece." Sensors 21, no. 19 (October 5, 2021): 6619. http://dx.doi.org/10.3390/s21196619.
Повний текст джерелаАнотація:
Lightfield microscopy has raised growing interest in the last few years. Its ability to get three-dimensional information about the sample in a single shot makes it suitable for many applications in which time resolution is fundamental. In this paper we present a novel device, which is capable of converting any conventional microscope into a lightfield microscope. Based on the Fourier integral microscope concept, we designed the lightfield microscope eyepiece. This is coupled to the eyepiece port, to let the user exploit all the host microscope’s components (objective turret, illumination systems, translation stage, etc.) and get a 3D reconstruction of the sample. After the optical design, a proof-of-concept device was built with off-the-shelf optomechanical components. Here, its optical performances are demonstrated, which show good matching with the theoretical ones. Then, the pictures of different samples taken with the lightfield eyepiece are shown, along with the corresponding reconstructions. We demonstrated the functioning of the lightfield eyepiece and lay the foundation for the development of a commercial device that works with any microscope.
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Laurion, Tristan A., and Richard L. Dolson. "Rotating specimen stage for angle-indexed videotape microscopy of automotive water-pump seals and ring-shaped specimens." Proceedings, annual meeting, Electron Microscopy Society of America 52 (1994): 458–59. http://dx.doi.org/10.1017/s0424820100170025.
Повний текст джерелаАнотація:
Videocameras and electronic image storage devices have given new vigor and potential to optical microscopy and parts inspection, as well as a powerful means of recording microscopic motion in live-time biological studies. Video and electronic techniques permit fast exploratory examinations simultaneous with extensive archiving, and allow the option of deferring hard copy printing to the time when reports may be needed. These capabilities aid in improving the quality of scanning electron microscopy (SEM) and other analyses that may follow and have great value in communicating with the customer.Our modular system was conceived to permit the imaging of the entire surface of ring-type objects as well to certify that features later characterized in more detail by SEM have been well chosen. The system uses the Nikon SMZ-U optical microscope equipped with a current technology video camera used in combination with a commercial frame grabber device, a dye transfer printer, and VHS videotape recorder.
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Song, Huixu, Qingwei Li, and Zhaoyao Shi. "Maximum Acceptable Tilt Angle for Point Autofocus Microscopy." Sensors 23, no. 24 (December 6, 2023): 9655. http://dx.doi.org/10.3390/s23249655.
Повний текст джерелаАнотація:
The complete and accurate acquisition of geometric information forms the bedrock of maintaining high-end instrument performance and monitoring product quality. It is also a prerequisite for achieving the ‘precision’ and ‘intelligence’ that the manufacturing industry aspires to achieve. Industrial microscopes, known for their high accuracy and resolution, have become invaluable tools in the precision measurement of small components. However, these industrial microscopes often struggle to demonstrate their advantages when dealing with complex shapes or large tilt angles. This paper introduces a ray-tracing model for point autofocus microscopy, and it provides the quantified relationship formula between the maximum acceptable tilt angle and the beam offset accepted in point autofocus microscopy, then analyzing the maximum acceptable tilt angle of the objects being measured. This novel approach uses the geometric features of a high-precision reference sphere to simulate the tilt angle and displacement of the surface under investigation. The research findings show that the maximum acceptable tilt angles of a point autofocus microscope vary across different measured directions. Additionally, the extent to which the maximum acceptable tilt angles are affected by the distances of the beam offset also varies. Finally, the difference between the experiment results and the theoretical results is less than 0.5°.
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Szcześniak, L., B. Hilczer, and K. P. Meyer. "Ferroelectric domain wall studied by scanning electron microscopy and electron microscope decoration technique." Ferroelectrics 172, no. 1 (October 1995): 227–34. http://dx.doi.org/10.1080/00150199508018480.
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Diep, Tai The, Sarah Helen Needs, Samuel Bizley, and Alexander D. Edwards. "Rapid Bacterial Motility Monitoring Using Inexpensive 3D-Printed OpenFlexure Microscopy Allows Microfluidic Antibiotic Susceptibility Testing." Micromachines 13, no. 11 (November 14, 2022): 1974. http://dx.doi.org/10.3390/mi13111974.
Повний текст джерелаАнотація:
Antibiotic susceptibility testing is vital to tackle the emergence and spread of antimicrobial resistance. Inexpensive digital CMOS cameras can be converted into portable digital microscopes using 3D printed x-y-z stages. Microscopic examination of bacterial motility can rapidly detect the response of microbes to antibiotics to determine susceptibility. Here, we present a new simple microdevice-miniature microscope cell measurement system for multiplexed antibiotic susceptibility testing. The microdevice is made using melt-extruded plastic film strips containing ten parallel 0.2 mm diameter microcapillaries. Two different antibiotics, ceftazidime and gentamicin, were prepared in Mueller-Hinton agar (0.4%) to produce an antibiotic-loaded microdevice for simple sample addition. This combination was selected to closely match current standard methods for both antibiotic susceptibility testing and motility testing. Use of low agar concentration permits observation of motile bacteria responding to antibiotic exposure as they enter capillaries. This device fits onto the OpenFlexure 3D-printed digital microscope using a Raspberry Pi computer and v2 camera, avoiding need for expensive laboratory microscopes. This inexpensive and portable digital microscope platform had sufficient magnification to detect motile bacteria, yet wide enough field of view to monitor bacteria behavior as they entered antibiotic-loaded microcapillaries. The image quality was sufficient to detect how bacterial motility was inhibited by different concentrations of antibiotic. We conclude that a 3D-printed Raspberry Pi-based microscope combined with disposable microfluidic test strips permit rapid, easy-to-use bacterial motility detection, with potential for aiding detection of antibiotic resistance.
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MORALES-SAAVEDRA, OMAR G., JÁKLI ANTAL, HEPPKE GERD, and EICHLER HANS J. "POLAR ORDERING IN THERMOTROPIC MESOGENS RESOLVED BY SCANNING NLO MICROSCOPY." Journal of Nonlinear Optical Physics & Materials 15, no. 04 (December 2006): 431–46. http://dx.doi.org/10.1142/s0218863506003396.
Повний текст джерелаАнотація:
A nonlinear optical (NLO) microscope has been developed based on recording the second harmonic generation (SHG) signals of the B 2- and B 4-phases of bent-shaped liquid crystalline (LC) materials. We observed that the microstructures of the polar order can be accurately characterized by 2D scanned images implementing this device. Specifically, we have investigated two bent-core compounds, which have either B 4 or B 2 phases at room temperature and exhibit SHG activity. The NLO microscope was calibrated according to the Maker fringe method allowing the in situ evaluation of the relative SHG efficiency. The developed NLO-microscopy device may serve as an important tool to characterize liquid crystalline features at a microscopic scale for both, fundamental and applied research.
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Gysin, Urs, Thilo Glatzel, Thomas Schmölzer, Adolf Schöner, Sergey Reshanov, Holger Bartolf, and Ernst Meyer. "Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices." Beilstein Journal of Nanotechnology 6 (December 28, 2015): 2485–97. http://dx.doi.org/10.3762/bjnano.6.258.
Повний текст джерелаАнотація:
Background: The resolution in electrostatic force microscopy (EFM), a descendant of atomic force microscopy (AFM), has reached nanometre dimensions, necessary to investigate integrated circuits in modern electronic devices. However, the characterization of conducting or semiconducting power devices with EFM methods requires an accurate and reliable technique from the nanometre up to the micrometre scale. For high force sensitivity it is indispensable to operate the microscope under high to ultra-high vacuum (UHV) conditions to suppress viscous damping of the sensor. Furthermore, UHV environment allows for the analysis of clean surfaces under controlled environmental conditions. Because of these requirements we built a large area scanning probe microscope operating under UHV conditions at room temperature allowing to perform various electrical measurements, such as Kelvin probe force microscopy, scanning capacitance force microscopy, scanning spreading resistance microscopy, and also electrostatic force microscopy at higher harmonics. The instrument incorporates beside a standard beam deflection detection system a closed loop scanner with a scan range of 100 μm in lateral and 25 μm in vertical direction as well as an additional fibre optics. This enables the illumination of the tip–sample interface for optically excited measurements such as local surface photo voltage detection. Results: We present Kelvin probe force microscopy (KPFM) measurements before and after sputtering of a copper alloy with chromium grains used as electrical contact surface in ultra-high power switches. In addition, we discuss KPFM measurements on cross sections of cleaved silicon carbide structures: a calibration layer sample and a power rectifier. To demonstrate the benefit of surface photo voltage measurements, we analysed the contact potential difference of a silicon carbide p/n-junction under illumination.
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Marshall, J. E. A. "A simple cost-effective infra-red microscope for palynology." Journal of Micropalaeontology 14, no. 2 (October 1, 1995): 106. http://dx.doi.org/10.1144/jm.14.2.106.
Повний текст джерелаАнотація:
Abstract. It has long been known that objects which are opaque in transmitted white light can become translucent in infra-red (IR) light. Its application to palynology was shown by Leclercq (1933) who used an IR filter to cut out the visible light from the specimen coupled with an IR-sensitive film to capture the image. Although the significance of this development was recognized (Walton, 1935), it was never generally used since oxidative methods such as Schulze’s solution are normally successful in clearing exines. The exceptions are opaque palynomorphs from thermally over-mature rocks. Such assemblages have been studied with IR microscopy using either IR-sensitive film on partially cleared material (e.g. Tiwari & Schaarschmidt, 1975) or electronic IR imaging systems (Cramer & Diez, 1972).The technical sophistication and performance of IR imaging microscopes has recently improved significantly following their routine application for the internal imaging of silicon chips. However, such microscopes are designed for use in reflected light and also rather costly. In addition their design makes them difficult to routinely switch from brightfield transmitted light to IR light without risk of damaging their sensitive IR tube. This note describes a simplified IR microscope for transmitted light which shows how excellent images of opaque spores in the near-IR can be produced using the simplest palynological microscope.This IR microscope is based around an Olympus BHSM-IR system. This is fitted with a 100W quartz halogen bulb which is essential for providing the required level of IR illumination. However, the only specific IR corrected optics this. . .
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Oyibo, Prosper, Satyajith Jujjavarapu, Brice Meulah, Tope Agbana, Ingeborg Braakman, Angela van Diepen, Michel Bengtson, et al. "Schistoscope: An Automated Microscope with Artificial Intelligence for Detection of Schistosoma haematobium Eggs in Resource-Limited Settings." Micromachines 13, no. 5 (April 19, 2022): 643. http://dx.doi.org/10.3390/mi13050643.
Повний текст джерелаАнотація:
For many parasitic diseases, the microscopic examination of clinical samples such as urine and stool still serves as the diagnostic reference standard, primarily because microscopes are accessible and cost-effective. However, conventional microscopy is laborious, requires highly skilled personnel, and is highly subjective. Requirements for skilled operators, coupled with the cost and maintenance needs of the microscopes, which is hardly done in endemic countries, presents grossly limited access to the diagnosis of parasitic diseases in resource-limited settings. The urgent requirement for the management of tropical diseases such as schistosomiasis, which is now focused on elimination, has underscored the critical need for the creation of access to easy-to-use diagnosis for case detection, community mapping, and surveillance. In this paper, we present a low-cost automated digital microscope—the Schistoscope—which is capable of automatic focusing and scanning regions of interest in prepared microscope slides, and automatic detection of Schistosoma haematobium eggs in captured images. The device was developed using widely accessible distributed manufacturing methods and off-the-shelf components to enable local manufacturability and ease of maintenance. For proof of principle, we created a Schistosoma haematobium egg dataset of over 5000 images captured from spiked and clinical urine samples from field settings and demonstrated the automatic detection of Schistosoma haematobium eggs using a trained deep neural network model. The experiments and results presented in this paper collectively illustrate the robustness, stability, and optical performance of the device, making it suitable for use in the monitoring and evaluation of schistosomiasis control programs in endemic settings.
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Holm, Jason. "A Brief Overview of Scanning Transmission Electron Microscopy in a Scanning Electron Microscope." EDFA Technical Articles 23, no. 4 (November 1, 2021): 18–26. http://dx.doi.org/10.31399/asm.edfa.2021-4.p018.
Повний текст джерелаАнотація:
Abstract This article provides a brief overview of STEM-in-SEM, discussing the pros and cons, recent advancements in detector technology, and the emergence of 4D STEM-in-SEM, a relatively new method that uses diffraction patterns recorded at different raster positions to enhance images offline in selected regions of interest.
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van Benthem, Klaus, Christina Scheu, Wilfried Sigle, Christian Elsässer, and Manfred Rühle. "Electronic Structure Investigations of Metal / SrtiO3 Interfaces Using EELS." Microscopy and Microanalysis 7, S2 (August 2001): 304–5. http://dx.doi.org/10.1017/s1431927600027598.
Повний текст джерелаАнотація:
Ni, Pd and Cr thin films were grown on (100)SrTiO3 surfaces by molecular beam epitaxy at substrate temperatures of TNJ, pd=650°C and Tcr =150°C. Electron energy-loss spectroscopy (EELS) and high resolution transmission electron microscopy (HRTEM) were applied to investigate the local electronic structure and the atomic structure of the interfaces, respectively. Analytical microscopy was carried out with a parallel energy-loss spectrometer (PEELS766) attached to a dedicated scanning transmission electron microscope (STEM) operated at 100keV, which has a point resolution of 0.22 nm. HRTEM studies were performed on a Jeol JEM ARM 1250 operated at 1250keV (0.12 nm point resolution). Conventional TEM and HRTEM experiments showed epitaxial orientation relationships between the thin metal films and the substrate for each interface.The electronic structure of the interfaces in terms of the site- and symmetry projected density of states (PDOS) above the Fermi-level can be extracted from the electron energy-loss near-edge structures (ELNES).
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Ippolito, Stephen, Sean Zumwalt, and Andy Erickson. "Emerging Techniques in Atomic Force Microscopy: Diamond Milling and Electrostatic Force Microscopy." EDFA Technical Articles 17, no. 3 (August 1, 2015): 4–10. http://dx.doi.org/10.31399/asm.edfa.2015-3.p004.
Повний текст джерелаАнотація:
Abstract Atomic force microscopy has been a consistent factor in the advancements of the past decade in IC nanoprobing and failure analysis. Over that time, many new atomic force measurement techniques have been adopted by the IC analysis community, including scanning conductance, scanning capacitance, pulsed current-voltage, and capacitance-voltage spectroscopy. More recently, two new techniques have emerged: diamond probe milling and electrostatic force microscopy (EFM). As the authors of the article explain, diamond probe milling using an atomic force microscope is a promising new method for in situ, localized, precision delayering of ICs, while active EFM is a nondestructive alternative to EBAC microscopy for localization of opens in IC analysis.
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Fu, Wen Wu. "Application of Virtual Network Electron Microscopy in Materials Science." Advanced Materials Research 898 (February 2014): 779–82. http://dx.doi.org/10.4028/www.scientific.net/amr.898.779.
Повний текст джерелаАнотація:
This paper first introduces the combination of virtual network and electronic scanner microscope, and uses nonlinear Burgers method to establish virtual network partial differential equations and the algorithm of scanning electron microscopy, and uses MATLAB software to draw the image of algorithm. It verifies the reliability of program. Finally, by using virtual network technology of scanning electron microscopy we obtained the contrast curve diagram of polypyrrole and sulfonated graphene, the image is displayed by three dimension of the virtual network. This method is extended to the teaching arrangement of the historical course and historical events. It provides a new idea and reference for the application of computer in teaching.
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Ali, Ashfaq, Naveed Ullah, Asim Ahmad Riaz, Muhammad Zeeshan Zahir, Zuhaib Ali Khan, S. Shaukat Ali Shah, Muftooh Ur Rehman Siddiqi, and Muhammad Tahir Hassan. "Development and Comparative Analysis of Electrochemically Etched Tungsten Tips for Quartz Tuning Fork Sensor." Micromachines 12, no. 3 (March 8, 2021): 286. http://dx.doi.org/10.3390/mi12030286.
Повний текст джерелаАнотація:
Quartz Tuning Fork (QTF) based sensors are used for Scanning Probe Microscopes (SPM), in particular for near-field scanning optical microscopy. Highly sharp Tungsten (W) tips with larger cone angles and less tip diameter are critical for SPM instead of platinum and iridium (Pt/Ir) tips due to their high-quality factor, conductivity, mechanical stability, durability and production at low cost. Tungsten is chosen for its ease of electrochemical etching, yielding high-aspect ratio, sharp tips with tens of nanometer end diameters, while using simple etching circuits and basic electrolyte chemistry. Moreover, the resolution of the SPM images is observed to be associated with the cone angle of the SPM tip, therefore Atomic-Resolution Imaging is obtained with greater cone angles. Here, the goal is to chemically etch W to the smallest possible tip apex diameters. Tips with greater cone angles are produced by the custom etching procedures, which have proved superior in producing high quality tips. Though various methods are developed for the electrochemical etching of W wire, with a range of applications from scanning tunneling microscopy (SPM) to electron sources of scanning electron microscopes, but the basic chemical etching methods need to be optimized for reproducibility, controlling cone angle and tip sharpness that causes problems for the end users. In this research work, comprehensive experiments are carried out for the production of tips from 0.4 mm tungsten wire by three different electrochemical etching techniques, that is, Alternating Current (AC) etching, Meniscus etching and Direct Current (DC) etching. Consequently, sharp and high cone angle tips are obtained with required properties where the results of the W etching are analyzed, with optical microscope, and then with field emission scanning electron microscopy (FE-SEM). Similarly, effects of varying applied voltages and concentration of NaOH solution with comparison among the produced tips are investigated by measuring their cone angle and tip diameter. Moreover, oxidation and impurities, that is, removal of contamination and etching parameters are also studied in this research work. A method has been tested to minimize the oxidation on the surface and the tips were characterized with scanning electron microscope (SEM).
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Stemmer, A., A. Engel, R. Häring, R. Reichelt, and U. Aebi. "Scanning tunneling microscopy of biomacromolecules." Proceedings, annual meeting, Electron Microscopy Society of America 46 (1988): 444–45. http://dx.doi.org/10.1017/s0424820100104285.
Повний текст джерелаАнотація:
Since its invention in the early 1980s the scanning tunneling microscope (STM) has rapidly evolved into a well established tool in solid state physics for surface structure analysis at atomic resolution. Recently a growing interest in the STM for investigating biological matter has been expressed, since surface ‘topographs’ of biomacromolecules can be recorded at ambient pressure or possibly in buffer solutions, thereby eliminating structural alterations induced by specimen dehydration such as required for electron microscopy (EM).As simple as a STM may look, it provides a wealth of information ranging from mere surface topography and local variations in the tunnel-barrier height to local spectroscopy of electronic states and elasticity. On the other hand the physics involved in imaging biological specimens such as protein or DNA, membranes, or fatty acid monolayers, which are generally known to be poor conductors, is not quite understood yet. To cope with insulators the atomic force microscope (AFM), a relative of the STM, provides a means to obtain topographs and elasticity data.
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Piston, David W., Brian D. Bennett, and Robert G. Summers. "Two-photon excitation microscopy in cellular biophysics." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 62–63. http://dx.doi.org/10.1017/s0424820100136684.
Повний текст джерелаАнотація:
Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.
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Smith, K. C. A. "Sir Charles William Oatley, O. B. E. 14 February 1904–11 March 1996." Biographical Memoirs of Fellows of the Royal Society 44 (January 1998): 331–47. http://dx.doi.org/10.1098/rsbm.1998.0022.
Повний текст джерелаАнотація:
Charles Oatley made three outstanding contributions to the engineering sciences: he was one of the brilliant team that developed radar in Britain during the Second World War; he revolutionized the teaching of electronics at Cambridge University; and he developed the scanning electron microscope. It is for the last of these that he will be chiefly remembered. He stands with Manfred von Ardenne as one of the two great pioneers of scanning electron microscopy His involvement with the instrument began shortly after the war when, fresh from his experience in the development of radar, he perceived that new techniques could be brought to bear which would overcome some of the fundamental problems encountered by von Ardenne in his pre–war research. Oatley's work led directly to the launch of the world's first series production instrument—the Stereoscan—in 1965. Thousands of scanning electron microscopes have since been manufactured and are to be found in practically every research laboratory in the world. The striking three–dimensional images of microscopic organisms produced have been used to illustrate countless newspaper and magazine articles, as well as scientific research papers, giving the general public a new perspective and appreciation of the world that lies beyond the resolution of the human eye. The scanning electron microscope is, arguably, the single most important scientific instrument of the post-war era.
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Wilson, R. J., D. D. Chambliss, S. Chiang, and V. M. Hallmark. "Resolution in the scanning tunneling microscope." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 488–89. http://dx.doi.org/10.1017/s042482010008674x.
Повний текст джерелаАнотація:
Scanning tunneling microscopy (STM) has been used for many atomic scale observations of metal and semiconductor surfaces. The fundamental principle of the microscope involves the tunneling of evanescent electrons through a 10Å gap between a sharp tip and a reasonably conductive sample at energies in the eV range. Lateral and vertical resolution are used to define the minimum detectable width and height of observed features. Theoretical analyses first discussed lateral resolution in idealized cases, and recent work includes more general considerations. In all cases it is concluded that lateral resolution in STM depends upon the spatial profile of electronic states of both the sample and tip at energies near the Fermi level. Vertical resolution is typically limited by mechanical and electronic noise.
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LE, THUC T., and JI-XIN CHENG. "NON-LINEAR OPTICAL IMAGING OF OBESITY-RELATED HEALTH RISKS: REVIEW." Journal of Innovative Optical Health Sciences 02, no. 01 (January 2009): 9–25. http://dx.doi.org/10.1142/s1793545809000371.
Повний текст джерелаАнотація:
This review highlights the recent applications of non-linear optical (NLO) microscopy to study obesity-related health risks. A strong emphasis is given to the applications of coherent anti-Stokes Raman scattering (CARS) microscopy where multiple non-linear optical imaging modalities including CARS, sum-frequency generation (SFG), and two-photon fluorescence are employed simultaneously on a single microscope platform. Specific examples on applications of NLO microscopy to study lipid-droplet biology, obesity-cancer relationship, atherosclerosis, and lipid-rich biological structures are discussed.
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Horky, D., I. Lauschova, M. Klabusay, M. Doubek, P. Sheer, S. Palsa, and J. Doubek. "Appearance of iron-labeled blood mononuclear cells in electron microscopy." Veterinární Medicína 51, No. 3 (March 19, 2012): 89–92. http://dx.doi.org/10.17221/5525-vetmed.
Повний текст джерелаАнотація:
Mononuclear cells from rabbit bone marrow were cultured for 14 days in cell-free medium for hematopoietic cells together with iron oxid nanoparticles, and then they were processed by technique for free cells for TEM (transmission electron microscopy). Staining with turnbull blue was used for the detection of iron using a light microscope. It was shown that iron nanoparticles were incorporated into the cytoplasm of mononuclear cells during 14 days cultivation. Here they were localized within different sized vacuoles with distinct membranes.
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Yang, Meng Tao, Feng Li, Yu Chao Wang, and Q. Y. Liu. "Synthesis of Selenium Nanoparticles in the Presence of Oyster Polysaccharides and the Antioxidant Activity." Applied Mechanics and Materials 522-524 (February 2014): 1143–46. http://dx.doi.org/10.4028/www.scientific.net/amm.522-524.1143.
Повний текст джерелаАнотація:
A simple method for synthesis of nanoselenium using oyster polysaccharides as soft template was investigated. The uniform stable selenium polysaccharides were obtained under the condition of reaction temperature 40°C, reaction time 3 h-5 h, the content of oyster polysaccharides 400mg/L and the content of sodium selenite 1mM. The size distribution and morphology of the product were confirmed by scanning electronic microscopy (SEM) and tansmission electronic microscope (TEM). The antioxidant activity of nanoselenium polysaccharides were studied in vitro. The results showed that nanoselenium polysaccharide is an effective hydroxyl radical and DPPH radical scavenger.
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MORALES-SAAVEDRA, OMAR G., ANTAL JÁKLI, GERD HEPPKE, and HANS J. EICHLER. "POLAR MICRO STRUCTURES OF THE B2- AND B4-PHASES OF BENT-SHAPED LC-MOLECULES RESOLVED BY NONLINEAR OPTICAL MICROSCOPY." Journal of Nonlinear Optical Physics & Materials 15, no. 02 (June 2006): 287–302. http://dx.doi.org/10.1142/s0218863506003293.
Повний текст джерелаАнотація:
A nonlinear optical (NLO) microscope has been developed based on recording the second harmonic generation (SHG) signals of the B 2- and B 4-phases of bent shaped liquid crystalline (LC) materials. We observed that the microstructures of the polar order can be accurately characterized by 2D scanned images implementing this device. Specifically, we have investigated two bent-core compounds, which have either B 4 or B 2 phases at room temperature and exhibit SHG activity. The NLO microscope was calibrated according to the Maker-fringes method allowing the in situ evaluation of the relative SHG efficiency. The developed NLO microscopy device may serve as an important tool to characterize liquid crystalline features at a microscopic scale for both fundamental and applied research.