Eyepiece

The magnification is rather chosen to be about 500 to 1000 where is the numerical aperture of the objective (see the next section) The eyepiece is then necessary to magnify the real image so that it can conveniently be inspected. 

Most fractography can be conducted with simple instmments such as a pocket magnifying eyepiece or an optical microscope. As with any detective work, it is important to maintain careful records and to pay close attention to details in the reconstmctions of the conditions under which fabrication and failure occurred. Seemingly unimportant details of fabrication, service, and/or the conditions under which failure occurred can frequently be the key to determining the cause of failure. 

To get a driving force the cell is pushed towards the cold block, which cools the interface below T, . The solid then starts to grow into the liquid and the growth speed can be measured against a calibrated scale in the microscope eyepiece. When the interface is cooled to 35°C the speed is about 0.6 mm mimk At 30°C the speed is 2.3 mm mimk And the maximum growth speed, of 3.7 mm mim, is obtained at an interface temperature of 24°C (see Fig. 6.3). At still lower temperatures the speed decreases. Indeed, if the interface is cooled to -30°C, there is hardly any growth at all. 

With polarizers fidly crossed and the specimen rotated to maximum brightness, the sample thickness is determined with the aid of a calibrated eyepiece micrometer, and the polarization (retardation) color is noted. From these the birefringence may be determined mathematically or graphically with the aid of a Michel-L vy chart. 

The elongated sample is next rotated parallel to an eyepiece crosshair, and one notes if the sample goes to extinction if it does, it has parallel extinction (the vibra-... 

OkuLar, n. (Optics) eyepiece, ocular, -muschel, /. (Micros.) eyepiece cup. okulieren, v.t. bud, graft (by budding). 

Schau-fenster, n. show window, -glas, n. display glass, specimen glass, sample glass sight glass (Optics) eyepiece, ocular (Meek.) oil gage. 

An industrial microscope with a long-working distance 20 X objective is used for the collection of the chromatic interference patterns. They are produced by the recombination of the light beams reflected at both the glass/chromium layer and lubricant/steel ball interfaces. The contact is illuminated through the objective using an episcopic microscope illuminator with a fiber optic light source. The secondary beam splitter inserted between the microscope illuminator and an eyepiece tube enables the simultaneous use of a color video camera and a fiber optic spectrometer. 

Laparoscopy A type of surgical procedure in which a small incision is made, usually in the navel. A viewing tube (laparoscope) which has a small camera on the eyepiece is inserted, allowing examination of the abdominal and pelvic organs using a video... 

The velocity of particle migration, v, across the field is a function of the surface charge or zeta potential and is observed visually by means of an ultramicroscope equipped with a calibrated eyepiece and a scale. The movement is measured by timing the individual particles over a certain distance, and the results of approximately 10-15 timing measurements are then averaged. From the measured particle velocity, the electrophoretic mobility (defined as v/E, where E is the potential gradient) can be calculated. 

An ocular micrometer is a disk on which is etched a scale in units from 0 to 50 or 100. To determine the micrometer value of each unit in a particular eyepiece and at a specific magnification, the unit must be calibrated with a stage micrometer. A stage micrometer has a scale 2 mm long ruled in fine intervals of 0.01 mm (10 finl). 

Insert the micrometer in the eyepiece so that the micrometer rests on the diaphragm, with the etched scale facing the eye. In many new microscopes, the micrometer can be dropped in and secured with a ring retainer. (It is helpful to have an extra ocular in which the micrometer may be left.)... 

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