Camera devices, types

Cylindrical alkaline cells are 2inc—manganese dioxide cells having an alkaline electrolyte, which are constmcted in the standard cylindrical si2es, R20 "D", R14 "C", R6 "AA", R03 "AAA", as well as a few other less common si2es. They can be used in the same types of devices as ordinary Leclanchn and 2inc chloride cells. Moreover, the high level of performance makes them ideally suited for appHcations such as toys, audio devices, and cameras. 

The energy density of the system depends on the type of cell as well as the current drain. Table 3 gives the specification for the various hthium systems. These coia cells have already been widely used ia electronic devices such as calculators and watches, whereas the cylindrical cells have found apphcations ia cameras. 

One very important device is the plate reader, which can be rate limiting in HTS. Most laboratories use multimodal readers that can detect various forms of fluorescence as well as luminescence and absorbance. The traditional readers are photomultiplier-based devices that usually read from one well to the next. This process can take considerable time for 384-well and higher-density plates. A more desirable HTS reader type images the entire plate with a charge-coupled device (CCD) camera. The latter device is usually a faster reader for 384-well and higher-density plates. Imagers can capture significant cross talk from one well to another, but with proper set up, they can produce data of equal quality. 

The photosensitive nature of selenium makes it useful in devices that respond to the intensity of light, such as photocells, light meters for cameras, xerography, and electric eyes. Selenium also has the ability to produce electricity directly from sunlight, making it ideal for use in solar cells. Selenium possesses semiconductor properties that make it useful in the electronics industry, where it is a component in some types of solid-state electronics and rectifiers. It is also used in the production of ruby-red glass and enamels and as an additive to improve the quality of steel and copper. Additionally, it is a catalyst (to speed up chemical reactions) in the manufacture of rubber. 

Appropriate electrophoresis systems in various sizes are available from numerous companies. More expensive are the imaging devices, usually consisting of a UV transilluminator and a CC-camera attached to a computer. There are several types of digital image analysers commercially available. Alternatively, one may use ordinary photography (use a red filter and UV-transilluminator) to obtain an image of the gel. 

There are another type of photocells known as barrier layer photocells which work on an entirely different principle. They are semiconductor devices in which impinging photons promote the electrons from the valence band to the conduction band across the energy gap. A photovoltagc is generated which can be measured by a voltmeter. Such photovoltaic devices can have a large surface area and are easy to operate. They are commonly used in many simple colorimeters and fluorimeters and as light Otters for cameras. 

The spark produced by a Leyden jar was the earliest light source used for the study of rapid events by photography (F.Talbot in 1851). This type of spark was first applied to ballistic investigations in 1884 by E.Mach P.Salcher. In later cameras, a spark was produced by electronic or other devices, such as "guided spark flashlamp , etc (See Ref l,pp 258-9 349 62 ... 

Schematically, two main systems can be used to collect 3D fluorescence data (time, wavelength, number of photons, see fig. 1). In a first type of system, light is directed into a monochromator connected to a photomultiplier tube and then to a fast oscilloscope (PM detection). The experimentalist thus collects luminescence decays at various wavelengths. This system is known to be very efficient for luminescence decay acquisition but is very time-consuming for the acquisition of emission spectra. In the second type of system, light is directed to a diode array detector (or CCD camera) and a subsequent electronic detection device (diode detection). The experimentalist collects emission spectra at various delay times (time zero for the pulse entering in the sample). This system is very efficient for emission data acquisition but, on the other hand, time-consuming for luminescence decay acquisitions. From this very schematic description, it appears that a system combining the two types of detections would be the optimum.

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