Vapor Lamps

Philips and Osram spectral discharge lamps have been used as spectral sources for analytical atomic fluorescence. These lamps have internal electrodes and produce intense spectral lines. The spectral lines, however, are subject to line reversal and the lamps are available only for a limited number of elements. Use of Philips and/or Osram lamps require careful control of input energy to produce maximum intensity without line reversal. Under these conditions they have produced satisfactory atomic fluorescence signals for some elements, including cadmium, mercury, zinc, and thallium. 

A mercury metal vapor lamp emits a very intense line spectrum. It is possible to use the line spectrum of mercury to excite the fluorescence spectra of elements other than mercury if line overlap exists. Omenetto and Rossi have been able, by this technique, to produce fluorescence spectra of iron, manganese, nickel, chromium, thallium, copper, and magnesium. Table 11-1 illustrates some of these results and also gives detection limits obtained by this method. 

Atomic Fluorescence of Several Elements Excited by a Mercury Discharge Lamp  

Element Fluorescence line, A Hg line, A Detection limit, /ig/ml 

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Scandium iodide added to mercury vapor lamps produces a highly efficient light source resembling sunlight, which is important for indoor or night-time color TV. 

The metal is widely used in laboratory work for making thermometers, barometers, diffusion pumps, and many other instruments. It is used in making mercury-vapor lamps and advertising... 

In contrast to spectrophotometry, hght-scattering experiments are generally conducted at constant wavelength. Mercury vapor lamps are the most widely used light sources, since the strong lines at 436 and 546 nm are readily isolated by filters to allow monochromatic illumination. Polarizing filters are also included for both the incident and scattered beams so that depolarization can... 

Niobium is used as a substrate for platinum in impressed-current cathodic protection anodes because of its high anodic breakdown potential (100 V in seawater), good mechanical properties, good electrical conductivity, and the formation of an adherent passive oxide film when it is anodized. Other uses for niobium metal are in vacuum tubes, high pressure sodium vapor lamps, and in the manufacture of catalysts. 

Ultraviolet light sources are based on the mercury vapor arc. The mercury is enclosed ia a quart2 tube and a potential is appHed to electrodes at either end of the tube. The electrodes can be of iron, tungsten, or other metals and the pressure ia a mercury vapor lamp may range from less than 0.1 to >1 MPa (<1 to >10 atm). As the mercury pressure and lamp operating temperatures are iacreased, the radiation becomes more iatense and the width of the emission lines iacreases (17). 

Lighting. An important appHcation of clear fused quartz is as envelop material for mercury vapor lamps (228). In addition to resistance to deformation at operating temperatures and pressures, fused quartz offers ultraviolet transmission to permit color correction. Color is corrected by coating the iaside of the outer envelope of the mercury vapor lamp with phosphor (see Luminescent materials). Ultraviolet light from the arc passes through the fused quartz envelope and excites the phosphor, produciag a color nearer the red end of the spectmm (229). A more recent improvement is the iacorporation of metal haHdes ia the lamp (230,231). 

Sodium vapor lamps, in use for many years, continue to be improved, both with respect to efficiency and color of emitted light. These lamps, however, contain only a few milligrams of sodium each. 

Minor uses of vanadium chemicals are preparation of vanadium metal from refined pentoxide or vanadium tetrachloride Hquid-phase organic oxidation reactions, eg, production of aniline black dyes for textile use and printing inks color modifiers in mercury-vapor lamps vanadyl fatty acids as driers in paints and varnish and ammonium or sodium vanadates as corrosion inhibitors in flue-gas scmbbers. 

A continuous source has to be employed to record absorption spectra. Fluorescence is usually excited with mercury vapor lamps in the region of their major bands they radiate more powerfully than do xenon lamps (Fig. 14). 

In contrast to the low-pressure lamps (1—130 Pa) which primarily emit at the resonance line at A = 254nm, high-pressure lamps (lO —10 Pa) also produce numerous bands in the UV and VIS regions (Fig. 16). Table 3 lists the emission lines and the relative spectral energies of the most important mercury lamps (see also [44]). The addition of cadmium to a mercury vapor lamp increases the numbei of emission lines particularly in the visible region of the spectrum [45] so that it i. also possible to work at A = 326, 468, 480, 509 and 644 nm [46]. 

However, the optical train illustrated in Figure 22B allows the determination of fluorescence quenching. The interfering effect described above now becomes the major effect and determines the result obtained. For this purpose the deuterium lamp is replaced by a mercury vapor lamp, whose short-wavelength emission line (2 = 254 nm) excites the luminescence indicator in the layer. Since the radiation intensity is now much greater than was the case for the deuterium lamp, the fluorescence emitted by the indicator is also much more intense and is, thus, readily measured. 

A mixture of 4 g of diazoketone (94) and 2.2 g of sodium bicarbonate in 200 ml of tetrahydrofuran and 180 ml of water is irradiated with a Hanovia 200 W mercury vapor lamp (using a Corex filter) until the starting material has been consumed. After addition of 500 ml of water, followed by extraction of nonacidic products, the solution is acidified, cooled to 0° and filtered to yield 2.95 g (76%) of white crystals of crude acid (95) mp 170-176°. An analytical sample has mp 188°. ° ... 

HID fixtures include those using mercury vapor and sodium vapor lamps. Mercury vapor fixtures are usually less expensive than sodium... 

Fireworks displays are fascinating to watch. Neon lights and sodium vapor lamps can transform the skyline of a city with their brilliant colors. The eerie phenomenon of the aurora borealis is an unforgettable experience when you see it for the first time. All of these events relate to the generation of light and its transmission through space. 

Sodium vapor lamps are commonly used to illuminate highways because of their intense yellow-orange emissions at 589 nm. 

Sodium bicarbonate, 112-113 Sodium carbonate, 61 Sodium chloride 44q common ion effect and, 439 electrolysis, 499 formation, 3 structure, 36 Sodium chlorine, 4 Sodium hydroxide, 61,84,441 Sodium hypochlorite, 369-370 Sodium stearate, 595 Sodium vapor lamps, 135 Solids... 

N 14.15% a deep blue solid, liq, or gas. The color of the liq is described as that of a coned ammoniacal Cu soln (Ref 2). The odor is described as earthy or similar to sewage sludge (Ref 2). Mp -196.6°, bp -84° (Refs 1 2) CA Registry No 334-99-6 Preparation. It was first isolated as a by-prod from the fluorination of Ag cyanide. Its formation was attributed to the presence of Ag nitrate or Ag oxide in the tech grade Ag cyanide used (Ref 2). The first prepn in good yield was by the irradiation in a sealed tube of a mixt of nitric oxide and trifluoromethyl iodide plus a small amt of Hg with the light from a Hg vapor lamp, yield 75% (Ref 3). 

An interesting suggestion was made by Levine in 1969. He supposed that the ketene formed photolytically from 1,2-naphthoquinone diazide could react with unreacted 1,2-naphthoquinone diazide to form a spirolactone-type addition product. This suggestion was tested experimentally almost twenty years later by Huang and Gu (1988). They irradiated 1,2-naphthoquinone diazide in dioxane in the presence of pyrene as sensitizer with a high-pressure mercury vapor lamp (Scheme 10-103). They did indeed obtain the spirolactonespiro(naphtho[4,5 2/,l/]furano-2-one)-3 T -inde-... 

Sodium vapor lamps, used for public lighting, emit yellow light of wavelength 589 nm. How much energy is emitted by... 

Mercury Vapor Lamp Zinc Vapor Lamp Cadmium Vapor Lamp... 

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