refined Electron_microscope Information, explanation, recent texts, monographs, and related patents.
Information & explanations, latest texts & monographs on Electron_microscope (including recent related patents.)


Electron microscope

The electron microscope can magnify very small details with high resolving power due to the use of electrons rather than light to scatter off material, magnifying at levels up to 500,000 times. Table of contents showTocToggle("show","hide") 1 History 2 Process 3 Types 4 Treatment 5 Disadvantages History The first electron microscope was built in 1931 by Ernst Ruska and Max Knoll. It was greatly developed through the 1950s and has allowed great advances in the natural sciences. The advantage of an electron beam is that it has a much smaller wavelength (see wave-particle duality), which allows a higher resolution - the measure of how close together two things can be before they are seen as one. Light microscopes allow a resolution of about 0.2 micrometres, whereas electron microscopes can have resolutions as low as 0.1 nanometers. Process High voltage electron beams from a cathode are focused by magnetic lenses on to the specimen. They are then magnified by a series of magnetic lenses until they hit photographic plate or light sensitive sensors - which transfer the image to a computer screen. The image produced is called an electron micrograph (EM). Types The Transmission electron microscope (TEM) produces images by detecting electrons that are transmitted through the sample, while the Scanning electron microscope (SEM) produces images by detecting secondary electrons which are emitted from the surface due to excitation by the primary electron beam. Generally, the TEM resolution is about an order of magnitude better than the SEM resolution, however, because the SEM image relies on surface processes rather than transmission it is able to image bulk samples and has a much greater depth of view, and so can produce images that are a good representation of the 3D structure of the sample. Treatment Samples viewed under an electron microscope have to be treated in many ways:
  • Cryofixation - is freezing a specimen so rapidly, to liquid nitrogen temperatures, that the water forms vitreous (non-crystalline) ice. This preserves the specimen in a snapshot of it's solution state. This technique produces the best specimen preservation, but isn't applicable to all specimens.
  • Fixation - is preserving the sample to make it more realistic. Glutaraldehyde - for hardening - and osmic acid - which stains lipids black - are used.
  • Dehydration - is the removing of water to be replaced with an embedding medium such as ethanol or propanone.
  • Embedding - supports the tissue for sectioning in a resin such as araldite.
  • Sectioning - produces thin slices for mounting. These can be cut on an ultramicrotome with a diamond knife to produce very thin slices.
  • Staining - uses metals such as lead and uranium to reflect electrons to give contrast between different structures.
  • Ion Beam Milling - thins samples until they are transparent to electrons by firing ions (typically argon) at the surface from an angle and sputtering material from the surface.
Disadvantages The samples have to be viewed in vacuums, as air would scatter the electrons. This means that no living material can be studied. The samples have to be prepared in many ways to give proper detail, which may result in artifacts - objects purely the result of treatment, and this gives the problem of distinguishing artifacts from material, particularly in biological samples. There have been a few scientists, such as Dr Harold Hillman, who believe that such artefacts are responsible for all the structures observed in biological samples by electron microscopy, rendering the techniques useless for these materials. Mainstream scientists maintain that the results from various preparation techniques have been compared, and as there is no reason that they should all produce similar artefacts, it is therefore reasonable to believe that electron microscopy features correlate with living cells. In addition, higher resolution work has been directly compared to results from X-ray crystallography, providing independent confirmation of the validity of this technique. Recent work performed on unfixated, vitrified specimens has also been performed, further confirming the validity of this techique. Electron microscopes are also very expensive to buy and maintain. Wikipedia articles containing electron microscope images:

This article is adapted from from Wikipedia All Wikipedia article text is available under the terms of the GNU Free Documentation License


Recent Electron_microscope related patents

From USPTO:
6718227: System and method for determining a position error in a wafer handling device
6717602: Image forming method and image forming apparatus, and electrostatic latent image developing toner used by the same
6717231: Trench isolation regions having recess-inhibiting layers therein that protect against overetching
6717202: HSG semiconductor capacitor with migration inhibition layer
6717187: Semiconductor optical device and the fabrication method
6717179: Semiconductor device and semiconductor display device
6717157: Mask inspecting apparatus
6717156: Beam as well as method and equipment for specimen fabrication
6717145: Mapping electron microscopes exhibiting improved imaging of specimen having chargeable bodies
6717144: Scanning electron microscope system
6717143: Beam alignment in a lower column of a scanning electron microscope or the like
6717141: Reduction of aberrations produced by Wien filter in a scanning electron microscope and the like
6717116: Semiconductor production device ceramic plate
6717109: Heatable mirror, method for producing a heat conductive layer, and the use thereof
6716925: Tire with a component made of a rubber composition comprised of a rubber having pendant hydroxyl groups and a rubber containing a nitrile moiety
6716923: Resin composition for powder molding
6716858: Methods for inhibiting diabetic complications
6716813: Use of antimicrobial proteins and peptides for the treatment of otitis media and paranasal sinusitis
6716803: Cleaning agent for a semi-conductor substrate
6716776: Nonwoven fabric made from filaments and artificial leather containing it
6716767: Contact planarization materials that generate no volatile byproducts or residue during curing
6716738: Method of fabricating multilayered UBM for flip chip interconnections by electroplating
6716726: Thin film semiconductor device containing polycrystalline Si--Ge alloy and method for producing thereof
6716650: Interface void monitoring in a damascene process
6716648: Method of manufacturing and testing semiconductor integrated circuit device
6716638: Measuring conducting paths using infrared thermography
6716628: Chondrogenesis promoters and indolin-2-one derivatives
6716589: Discordant helix stabilization for prevention of amyloid formation
6716572: Manufacturing process for printed wiring board
6716570: Low temperature resist trimming process
6716567: Supporting body for lithography block and original lithography block
6716564: Radiation-sensitive resin composition
6716561: Toner for developing electrostatic latent image and image forming method using same
6716557: Anode material for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery using such anode material
6716551: Abraded fluid diffusion layer for an electrochemical fuel cell
6716548: Composite electrolyte membranes for fuel cells and methods of making same
6716542: Sputtering target for production of a magnetic recording medium
6716540: Multilayer film formed body
6716524: Rare earth borate and making method
6716521: Polyester composition, film made thereof, and magnetic recording medium
6716516: Magnetic recording medium and magnetic recording apparatus using the same
6716511: Propylene polymer fibers and yarns
6716495: Ink-jet recording apparatus and recording medium
6716480: Transparent conductive layered structure and method of producing the same, coating liquid for forming transparent coating layer and coating liquid for forming transparent conductive layer
6716479: Tailoring piezoelectric properties using MgxZn1-xO/ZnO material and MgxZn1-xO/ZnO structures
6716409: Fabrication of nanotube microscopy tips
6716389: Tantalum and tantalum nitride powder mixtures for electrolytic capacitors substrates
6716378: Method for forming hierarchically ordered porous oxides
6716370: Supramolecular oxo-anion corrosion inhibitors

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