Sequential irradiation

An equimolar (10 mmol) mixture of benzoyl chloride and n-butyl oxide adsorbed on 5 g graphite A was sequentially irradiated with 90 W incident power. The conversion reached 80% (Yield of isolated n-butyl benzoate (69) 62%). With ethyl oxide, the yield of ethyl benzoate (68) was lower, but noteworthy considering the volatility of this oxide, and the significant retentive power of graphite towards organic compounds. These preliminary results have not yet been expanded, but it is certain that more reactive ethers, like those substituted with sec- or teri-alkyl, benzylic or allylic groups, are deavable in the same way. 

Alternatively, chemical patterns can be generated by photohthography of a photoresist layer that has been spin-coated over a silane film. Upon irradiation through a mask and subsequent development of the photoresist pattern, the imderlying modified layer is revealed and is able to react with the ONDs. By sequentially irradiating the surface, it is possible to immobihze different ONDs. 

Single-component irradiations have provided useful information concerning certain projectile/surface interactions which contribute to plasma contaminant release and surface damage and erosion, but they cannot yield any information about interactive (synergistic) surface effects. These arise when two or more plasma radiation components interact simulaneously with surfaces, together producing plasma contaminant release and/or surface erosion either larger or smaller than that expected from a simple summation of the effects caused by the individual radiation components. Interactive effects can also occur after sequential irradiations. 

Imaging and fixing radiation-sensitive compositions by sequential irradiation. 

Figure 16 CD spectra of a thin film (340 nm) of 41 on glass, as prepared (full line) and after sequential irradiation of l-CPL (dashed line) and r-CPL (dotted line) at 488 nm (7—160 mW cm 2). (Reproduced from Ref. 99 2002, Wiley-VCH.)...

With the neutron activation procedure, the measurement of P is reliable only when there is very little Al (<20 ppm), or when an epithermal irradiation (Cd-covered) is used to correct for the direct activation of 28Al from the Al. For badly contaminated samples, the X-ray fluorescence data are more suitable for the P determination. The sequential irradiation procedures (with and without cadmium) showed that many of the mummy samples were contaminated to some extent and contained more than 20 ppm of Al. 

The NAA method can be divided into NAA (Instrumental NAA) and RNAA (Radiochemical NAA). In the latter, the various neutron-induced products are separated chemically to minimize interferences. There are several comprehensive review papers on INAA published in the literature 1,2,3,4). Briefly, the basic parameters controlling sensitivity for a multi-element determination are neutron flux, irradiation time, delay interval prior to counting, half-life and gamma-ray energy of the induced activity, and eflBciency and resolution of the detector. Table I outlines the irradiation parameters used for each of the two sequential irradiations. The final count occurring 40-50 days after the second irradiation is performed on an anti-coincidence-shielded Ge(Li) system developed recently in our laboratory. 

Each experiment should include an untreated unirradiated control. In addition an untreated irradiated control should also be included with every group of irradiated samples. This is to allow for any change in irradiation exposure between sequential irradiation steps. 

Two other drawbacks follow from a construction aspect as there is no modification of power as the oven only operates by sequential irradiation between the maximum and zero and no possibility of in situ temperature check. 

Welge and co-workers (Schnieder et al [ ]) have developed a resonant ionization technique for hydrogen atoms which allows the determination of the velocity to -0.3% by a time-of-flight method. The hydrogen atoms are sequentially irradiated in the detection zone with a 121.6 nm laser, which is resonant with the = 2 <- = 1 transition, and -365 nm light to produce high- Rydberg atoms ... 

Recovered Ge products Continuous irradiation Sequential irradiation, 2 min x 4... 

Applied incident power sequential irradiation time interval between two irradiations 2 min, except entry 5, 1 min 40 s Products 2,4-MeO(C6H3)COPh (73), Me(C6H4)COPh (74), CioHgCOPh (75), PhCOPh (76), p-Me3Si(C6H4)COPh (77) Conversion determined by GC yield of isolated product (in brackets) relative to the minor reagent fp o = 85 15 Sa-.p = 55 45 V" = 95 5... 

Scheme of embrittlement of reactor pressure vessel under re-irradiation of sequentially irradiated and annealed materials. 

Fig. 35. Critical cunent density (H c) at 77K of an Y-123 single crystal as a function of f t neutron fluencc. The crosses refer to sequential irradiation without atmealing, the solid symbols to sequential irradiation prior to aimealing, and the open symbols to the results alter annealing (Sauerzopf 1998).

Duration Stabilized UHMWPE was the first annealed crosshnked material. Crossfire annealed highly crosshnked UHMWPE (Stryker Orthopaedics, Mahwah, New Jersey, USA) was introduced for total hip components in 1998. In 2005, X3 (Stryker Orthopaedics, Mahwah, New Jersey, USA), a sequentially irradiated and annealed UHMWPE, was introduced. This material was developed based on experience with its predecessors with the intention of using the current data to produce a highly crosshnked UHMWPE available for both the hip and the knee. 

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