Radiation chopped

Applications of radiation grafting in the coating industry for improving adhesion and other properties has been an active field. For instance, grafting of styrene onto polyester fibers was found to improve the interfa-cial adhesion between grafted chopped polyester fibers and polystyrene used as a matrix [139]. 

For early-stage diffuse, aggressive NHL, combined-modality therapy was tested versus a longer course of chemotherapy.22 Overall survival favored the CHOP/radiation arm for 5 years (82% versus 72%). There was a trend toward increased toxicity, particularly hematologic and cardiac toxicity, in the CHOP alone arm. The results of this trial have established combined-modality therapy as first-line treatment for early-stage NHL. Unique presentations of NHL, such as CNS primary disease, may incorporate radiation into treatment algorithms.23... 

Stage I and nonbulky stage II should be treated with three to four cycles of rituximab and CHOP (R-CHOP) (Table 64-3) followed by locoregional radiation therapy. 

Patients with at least one adverse risk factor should receive six to eight cycles of R-CHOP followed by locoregional radiation therapy. 

A spectrometer with rapid response electronics should be used for electrothermal atomization, as it must follow the transient absorption event in the tube. Automatic simultaneous background correction (see Section 2.2.5.2) is virtually essential, as non-specific absorption problems are very severe. It is important that the continuum light follows exactly the same path through the furnace as the radiation from the line source (assuming a deuterium lamp is being used rather than Smith-Hieftje or Zeeman effect). The time interval between the two source pulses should be as short as possible (a chopping frequency of at least 50 Hz) because of the transient nature of the signal. 

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)].

All the photoconductive devices need to be operated in conjunction with amplifiers, and ac amplification of a chopped signal is most satisfactory. The author also finds chopping the radiation and ac amplification followed by phase-sensitive detection to be the best way of amplifying photomultiplier signals, and it may be of interest to describe the system... 

The radiation has to be chopped, and so the detector receives pulses of radiation from the source and the chopper alternately. Therefore the temperature is measured relative to the temperature of the chopper surface. In practice, radiometers are calibrated so that the temperature can be read directly from a scale. A particular commercial model which operates over the temperature range 0-600 °C uses a LiTa03 single crystal as the pyroelectric detector. 

Cary 14 diagram (ca. 1953) The arrows on the optical diagram trace the path of the UV and vis radiation through the instrument. Radiation from the D2 or W lamp is directed to the monochromator entrance slit D by appropriate lenses and mirrors. From mirror E it travels to prism F where it is refracted, then to mirror G which reflects it to variable-width intermediate slit H. Mirror I reflects the radiation to grating J and from there the monochromatic beam is directed to mirror K and exits the monochromator through slit L. Semicircular mirror O, driven by motor Q, chops the beam at 30 Hz and alternately sends half the beam to the reference and half to the sample. Elements V, V1, W, and W1 pass the separated beams to the phototube. The light pulses of the two beams are out of phase with each other so that the phototube receives light from only one beam at a time. The photomultiplier for UV-vis work is shown at X and the NIR detector for 700-2600 nm is shown at Y. 

If a gas that is infrared active is subjected to a source of chopped radiation, the energy absorbed into the internal degrees of freedom will be transferred by collision to translational energy. The result is then a pressure increase, giving rise to acoustical energy. The time lag between the absorption of the radiation and the appearance of a sound pulse is a measure of the relaxation time. The effect is described in considerable detail by Cottrell and McCoubrey [9], together with some experimental results of various investigators. A 1967 publication by Cottrell, Macfarlane, and Reed [135] describes the use of such an apparatus ( spectrophone ) in the study of V - V transfer in C02. 

In optical null instruments, radiation is passed through the sample and reference paths simultaneously or the instrument may be designed to pass the radiation through each path alternately (pre-sample chopping). A wedge or comb attenuator is moved in or out of the reference beam until absorption in both beams is equal. The movement of the... 

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