Source of illumination

In order to increase the homogeneity of the light light-filter, consisting either of a plate of solid potassium bichromate or of a solution of this substance, is often inserted between the flame and the polarizer. 

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The reaction gives off a brilliant white light, which served as a source of illumination in the headlights of early automobiles. 

R) Pbotoelectric Cell Camera. A camera using a photoelectric cell as a source of illumination. 

The distinction is fairly clear so far as emitted light and reflected light are concerned. To an observer, a lamp may have about the same color as that of the image of the lamp seen in some mirror. If the mirror is replaced by a piece of white paper, the viewer will see only the paper, but it will appear to be of about the same color as was the light, although less bright and modified by the whiteness of the paper. If the paper is colored, its apparent color will be a combination of the colors of the paper and the source of illumination. 

It should be noted that passive imaging systems can, of course, be enhanced by using active sources of illumination. This is primarily useful for shorter range applications and can improve the performance of the system in situations where the signal is weak or the contrast is low. 

Fig. 10.6. An incoming photon from a source of illumination on a p-type electrode makes an electron photoactivated and reaches the conduction band where it electrodiffuses to the surface and emits to energy levels in a suitable ion. The hole created will move toward the bulk and form a photocurrent in the external circuit.

Source of illumination Visible light High-speed electrons... 

I was somewhat puzzled, but contemplated the cup in the moonlight streaming through the window, the only source of illumination in the room. 

There are no additive sources of illumination giving the equivalents of all the colours in the solar spectrum with equal saturation. Thus, for example, the blue-green of the spectrum must be flattened by the addition of some red before it can be matched with the available primaries. Expressed in another way, the spectral blue-green y... 

The catalytically active state of the radical SAM cluster was first clearly demonstrated via single turnover experiments performed on the PFL-AE. In these experiments, PFL-AE was reduced from the [4Fe S] state to the [4Fe S] state by photoreduction with 5-deazariboflavin by removing the source of illumination, the two specific states of the cluster could be examined for their ability to generate the glycyl radical on PFL in the absence of exogenous reductant. It was found that the quantity of glycyl radical generated on PFL was... 

The tracer method is the most accurate technique to measure fluid velocity. The method is well developed for fluid flows (Somerscales, 1981). It involves use of light-sensitive particles mixed with the fluid, an optical source of illumination, and a detection system. But for solid/liquid and solid/gas flows, a better approach is to use radioactive tracers. Typically, the tracers are low-level, short-lived radioactive particles that can be either introduced manually or generated on line by a neutron source. Both methods will be described latter in this chapter. 

Acetylene was discovered by the British chemist Edmund Davy (1785-1857) in 1836. Davy obtained the gas accidentally when he combined water with potassium carbide (KCH2) while attempting to make potassium metal. He noted that the gas burned with a bright flame and thought it might he used as a source of illumination. That application was impractical, however, because of the high cost of potassium carbide. When the German chemist Frederich Wohler (1800-1882) discovered the far less expensive calcium carbide... 

Acetylene was used as a source of illumination beginning in the early 1900s. In one type of acetylene lamp, water was allowed to drop on a solid chunk of calcium carbide at a controlled rate. The acetylene produced then passed into an ignition chamber, where it burned with a brilliant white light. Acetylene lamps were... 

A line of dusty windows was the sole source of illumination inside. The aeroambulance was a hulking dark presence in the middle of the concrete floor. Three people were standing below the plane s narrow, pointed nose the woman who had spoken, and a pair of fiveyear-old twin girls. She introduced herself as Felicia Cantrell, her daughters were Ellen and Tammy her husband Ivan was an aeroambulance pilot, the man who had opened the door. "And Duggen you already know, or at least he knows you."... 

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