Halogen light bulbs

Superluminescent LEDs (SLEDs) are LEDs pumped at high current so that stimulated emission occurs. These miniature light sources are approximately 1000 times brighter than a tungsten-halogen light bulb. 

Noncontact-type heating allows heat transfer by noncontacting methods to fluids such as radiative and ultrasonic heating. Infrared temperature control [4] is a noncontact heating technique, which uses the infrared excitation of a vibration band of water combined with a high-power halogen light bulb and an optical Alter (Fig. 2). 

Halogen Light Bulbs Self-Healing Gas Corrosion/Chemical Vapor Deposition Equilibrium... 

The second difference is the gas inside the bulb. Inside a normal light bulb, the gas is usually argon, but the gas inside the quartz halogen bulb is iodine vapour at low pressure, which has the ability to combine chemically with tungsten vapour. When the temperature is sufficiently high, the halogen... 

Every substance at a finite temperature continually radiates energy, with a distribution (spectrum) which depends on the surface temperature. Figure 5.1 shows these spectra for two different temperatures 5800K (the surface temperature of the sun) and 3000K (the surface temperature of the tungsten filament in a household halogen lamp, which is a special kind of incandescent light bulb). 

Photoinduced free-radical halogenation is very useful for the functionalization of electron-deficient alkenes such as vinyl halides. Among halides, the addition of bromine is by far the most useful reaction, as shown in Scheme 3.25. In the first example, a polyfluoroalkene was brominated in a high yield by using a 300 W light bulb as the light source. Of note, the synthesis of l,2,4-tribromo-l,l,2-trifluorobutane (38) was carried out under solvent-free conditions in a near-quantitative yield and on a multigram scale (Scheme 3.25a) [67]. l,2-Dibromo-l,l,2-trichloroethane (39) was likewise obtained in about 250 g amounts by the solar lamp irradiation of neat trichloroethylene to which bromine was continuously added (Scheme 3.25b) [68],... 

Scheme 11.4 illustrates some representative halogenation reactions. The reaction in Entry 1 was conducted by slow addition of bromine to excess 2-methylpentane at 60°C, with irradiation from a tungsten light bulb. The reaction in Entry 2 is a typical benzylic bromination, carried out at 125°C with irradiation from a sun lamp. Entries 3 and 4 are examples of NBS bromination using benzoyl peroxide as the initiator. Entry 3 is interesting in that none of the allylic isomer 2-bromo-3-heptene is found. Entries 5 and 6 are examples of chlorination by f-butyl hypochlorite in which the f-butoxy radical is the chain carrier. Note that in Entry 6, both the primary and secondary allylic products are formed. The reaction in Entry 7 uses sulfuryl chloride as the halogenation reagent. Note that in contrast to chlorination with CI2 (see p. 1021), the reaction shows selectivity for the benzylic position. 

Fig. 3. A plant leaf imaged with epi-illumination using a 20 x obj ective, showing two stomata, (a) Epi-illumination using a halogen light, (b) Same as in (a) except with the addition of an incident light, (c) Epi-illumination with fluorescence light (mercury light bulb without any filter).

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