Xenon flash lamps

For the examination of the applied metallic or ceramic layer, the test object is heated up from the outside The heat applying takes place impulse-like (4ms) by xenon-flash lamps, which are mounted on a rack The surface temperature arises to approx 150 °C Due to the high temperature gradient the warmth diffuses quickly into the material An incorrect layer, e g. due to a delamiation (layer removal) obstructs the heat transfer, so that a higher temperature can be detected with an infrared camera. A complete test of a blade lasts approximatly 5 minutes. This is also done automatically by the system. In illustration 9, a typical delamination is to be recognized. 

There has been a tremendous change in the last two decades as computers have taken over the tedious calculations involved in color measurement. Indeed, microprocessors either are built into or are connected to all modem instmments, so that the operator may merely need to specify, for example, x,j, Y or T, i , b or T, (A, b, either for the 2° or the 10° observer, and for a specific standard illiiminant, to obtain the desired color coordinates or color differences, all of which can be stored for later reference or computation. The use of high intensity filtered Xenon flash lamps and array detectors combined with computers has resulted in almost instantaneous measurement in many instances. 

In the laser photolysis experiments the aromatic compound (4-10" M) and the nucleophile (0 04 M ) in acetonitrile-water (1 1) were irradiated with the frequency doubled pulse (100 mj, 6 ns, 347 nm) of a ruby laser. Only time-dependent absorption changes were measured (double pulsed xenon flash lamp with 10 /is continuous output as light source) absorption spectra were constructed from these measurements at 12 or 25 nm intervals. 

Chance and co-workers have designed a flow system where the protein is continuously pumped optically using a tungsten or xenon flash lamp (764 nm). Using continuous illumination for various times and temperatures. Chance et al. have observed three intermediate states upon MbCO photolysis. At 40 K, a state with a recombination rate constant of 2 x 10 /s has been identified from two slower states with rate constants of 10 /s. 

Bhaumik et al. (63) have reported the design of a stroboscopic instrument that is a substantial improvement upon the basic design of Peterson and Bridenbaugh. This apparatus makes use of a PEK-XE9-2 100-nsec xenon flash lamp as the excitation source. The lamp is fired on the order of 50 times a second with a peak input power of 4 Mwatts. The average power is reasonably low, being about 20 watts. 

The decay curves for the europium 5D0 state for the singly doped and the codoped crystals were also obtained. These data were collected using a repetitively pulsed xenon flash lamp and the excitation was in the form of broad-band 5-/zsec bursts. The detection was by means of a pulsed photomultiplier tube. All measurements were made at room temperature, and Fig. 39 shows these results. 

Figure 52. Fluorescent-decay curves of the 4/9/2 >4fi5/2 transition of CaF2i(0.1 Er3+). In (a) the ion is excited with 2550-A monochromatic radiation emitted by a 50-/xsec xenon flash lamp. The curve is resolvable into the difference of two exponentials with r = 400 50 and r2 = 200 50 / sec. In (b) the ion is excited with 2537-A radiation from an electronically chopped low-pressure mercury lamp. The steady state of fluorescence was established each time before the mercury lamp was switched off electronically. The afterglow in the lamp was of the order of 10 / sec [from Ref. (762)].

There are three instrument designs in use with fiber-optic probes. One system makes simultaneous measurements on up to eight dissolution bath probes using a CCD-based spectrophotometer with xenon flash lamp source. The signals from all eight probes are simultaneously imaged onto a single CCD detector and concentrations determined in real... 

Fiber-optic UV-vis spectrophotometers are well suited to a clean-in-place application. For analytes with signals in the deep UV, best results will be obtained with a deuterium source and short fiber runs. Further out in the UV and visible regions, a xenon flash lamp... 

Figure 1. Experimental system used in the time resolved absorption measurements. (EL=excimer laser, KrF, 248nm DG=delay generator OMA=optical multichannel analyser MC=monochromator and gated diode array detector C=cell X=xenon flash lamp L=lenses )...

The flash method entails a short pulse of high intensity energy, absorbed by the front surface of a small specimen shaped in the form of a disk. The radiant energy source can be a (xenon) flash lamp, laser, or electron beam. The energy absorbed on the front surface propagates (conduction, and at higher temperatures, radiation) toward the back surface, as depicted in Figure 9.8. 

Trivalent neodymium absorbs strongly in broad bands in the green, red and near infra-red with reasonable coincidence in the output of a xenon flash lamp. Nearly all the electrons excited into the pump bands revert to the metastable upper level 4F3/2 through non-radiative decay which has a lifetime of 230 ps. Radiative transition then occurs to a set of lower energy levels 4I)5/2,4Ii3/2,4I 1/2,4l9/2- All these levels are multiplets and the lowest of 4l9/2 is... 

For example, the direct photolysis of trichloroethene in air with UV-C radiation (using a xenon flash lamp) initially produced dichloroacetyl chloride ([CI2HC-COCl] >90%) that subsequently was photooxidized to yield phosgene ([Cl2C=0] < 25%), trichloroacetyl chloride (TCAC, [CI3C-COCI] < 2%), unidentified intermediates, and ultimately HCl and CO2 were produced (Haag et al., 1996). In this connection, it is relevant to stress that dichloroacetyl chloride is 40 times more toxic than trichloroethene (cf. Haag et al., 1996). 

Snch probes, which can be excited in the UV nsing a nitrogen laser or a Xenon flash lamp, emit their fluorescence between 500 and 700 nm, depending on the specific... 

Europium cryptates are excited in the UV wavelength range either by a xenon flash lamp or by a nitrogen laser. Their fluorescence occurs in a wavelength range between 550 and 710 nm with typical narrow emission lines. Since the electronic transitions of the europium ion are forbidden by quantum mechanical rules, the cryptate fluorescence lifetime is exceptionally long, in the range of 100-1000 J,s. 

Light source Tungsten filament lamp LEDs, xenon flashlamp LEDs Tungsten halogen lamp Xenon flash- lamp Mercury vapour lamp Tungsten halogen lamp... 

New xenon plasma fiashlamps, which generate significant light intensity in the deep UV region (<250 nm) are better suited for direct photolysis than conventional mercury-based UV lamps. Spectra of xenon flash lamps are different than those of the mercury arc lamps and in the range of IR to the UV-C region (300-200 nm) (23). The spectral emission of the xenon flash lamps depends on the current density and the plasma temperature. 

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