Electron scanning type

Fig. J. Simplified diagram of scanning-type electron microscope...

A block diagram of a scanning-type electron microscope is given in Fig. 5. Major elements of the instrument include the electromagnetic lenses that are used to form the electron probe, the scan coils that sweep the beam over the sample, the detector that collects the secondary electrons, and the amplifying means where the secondary electrons are amplified and fed to the cathode ray tube for display. Since the cathode ray tube is scanned in synchronization with the electron beam, the resulting picture corresponds to the area of the sample being examined. 

Characteristics. Electron-beam exposure experiments were carried ut by using a prototlype HL-600 Hitachi Electron-Beam Lithography System which is a vector scanning type variable-shaped electron-beam machine. The acceleration voltage was 30 kV. Resist films were formed on silicon wafers by spin-coating and prebaked at 80 C for 20 min before exposure. 

The metal coupons in the horizontal reactor were exposed at reactor temperature to either acetylene, ethylene, propylene, or butadiene for 120 minutes. The coupons were removed from the furnace, and pictures of the coke were taken using a JSM-U3 scanning electron microscope. Most pictures were taken using a magnification of 10,000. The type of metal in the coke was determined using EDAX Model 707, that was attached to the electron scanning microscope. 

Patterning of the Resist Resists were delineated with a vector scanning type, shaped electron-beam drafting machine, specially designed by the Hitachi Central Research Laboratory. The acceleration voltage was 30kV. 

The development of investigation techniques, particularly the electron scanning microscopy, allowed to differentiate the other morphological types of the calcium... 

Iron microscope can be used with thicker specimens and forms a perspective im e, although the resolution and m nification are lower. In this type of instrument a beam of primary electrons scans the specimen and those that are reflected, together with any secondary electrons emitted, are collected. This current Is used to modulate a separate electron beam in a TV monitor, which scans the screen at the same frequency, consequently building up a picture of the specimen. The resolution is limited to about 10-20 nm. See also field-emission microscope EIELD-IONIZATION MICROSCOPE. 

The apparatus which generated and accelerated the electron beams is named an electron gun. Thermal electron emission type electron guns are used for general SEM, but a SEM equipped field emission type electron gun is called EE-SEM (field-emission scanning electron microscopy), which can obtain the higher resolution images with lower applied voltage. 

The chemical structure of the two polymers can be characterized by several techniques Fourier transform infrared (FTIR) nuclear magnetic resonance (NMR) x-ray diffraction (XRD) transmission electron microscopy (TEM) scanning electron microscopy (SEM) mass spectroscopy (MS) ultraviolet spectrometry (UV) and electron scanning for chemical analysis (ESCA). The chemical structure of the two polymers can be analyzed by IR, NIR, or various types of NMR spectroscopy. Determining the structure of chitin and chitosan usually requires the application of combination of various methods. The combination of IR, NIR, and various techniques of NMR give ample information on the chemical structure. IR, NIR, and various types of NMR are less sensitive than that of other quantitative analysis such as UV, HPLC, GC, and MS. 

Another feature common to all HRM constructs is the smoothness of their surface [82,83,87]. It is generally better than 0.6-0.8 nm in terms of the standard density fluctuation about its mean value. That is much less than the diameter of an individual macromolecule. The surface of a carefully prepared multilayer assembly of PcPS is, for example, completely featureless, if investigated by either transmission or scanning type electron microscopy. 

Glassy carbons (GCs), obtained by pyrolysis and heat treatment of thermosetting resins above 1000°C, are hard and brittle materials that fail suddenly when loaded in tension or compression. In commercially available GCs, the mean grain diameter, evaluated from micrographs under a field-emission electron gun type scanning electron microscopy, and the crystallite sizes, calculated from X-ray powder diffraction profiles, both slightly increased with the elevation of heat treatment tempera-ture(HTT) from 1000°C to 3000°C. ... 

FIGURE 5.6 These PET scans of the brain show a normal brain on the left and a brain affected by Alzheimer s disease on the right. When positrons collide with electrons, what type of radiation is produced that gives an image of an organ ... 

The cell size arid morphology of PP and PC/ABS microfoam were determined by using scanning electron microscope type Cam Scan MV 2300 LV (SEM). 

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