Irradiation requirements

The high doses of irradiation required probably mostly also bring about changes in the constituents. 

A similar study has been reported with ortho-hydroxychalcones in dry media on silica gel [107]. Conventional thermal cydization, under the same conditions as for microwave irradiation, required a much longer reaction period (Eq. (57), Tab. 3.24, and Scheme 3.18). 

The least irradiation required for the dissolution of polymer coating in the developer. 

In the simultaneous method, which is the one most commonly used, the substrate is irradiated while in direct contact with the monomer. The monomer can be present as a vapor, liquid, or solution. This grafting process can occur via free radial or ionic mechanism. With the simultaneous method, the formation of homopol5mier is unavoidable, but there are several systems to minimize it. The advantage of this method is that both monomer and substrate are exposed to the radiation source and both form reactive sites. The other two techniques rely upon rupture of the bond to form reactive sites, and therefore require higher radiation doses. Thus, the simultaneous method is more suitable for substrates sensitive to radiation. The simultaneous method can utilize UV radiation besides EB source. Logically, the UV irradiation requires a photoinitiator or sensitizer to achieve an acceptable level of grafting. 

Hours of target decay following neurtron irradiation required to attain the maximum Os value due to a delayed formation by 191 10 decay (T1 /2= ) ... 

The energy density of the laser irradiation required to melt the dye and to induce diffusion will be given by ... 

Photosensitizer Parameters and Light Dose ihvgo) Under Broad-Band Irradiation Required to Kill 90% of Melanoma... 

The extension of the techniques of measuring the radiation emitted during the activating collision to pile irradiation requires a method of detection sensitive to the nuclear event but relatively insensitive to the pile neutron and gamma flux. Stewart and Bentley 97) estimated uranium... 

The sudden increase in crater depth observed during high irradiance (> 10 W/cm ) laser ablation of silicon [17], which has been ascribed to phase explosion, can be used to establish a new threshold the threshold irradiance for phase explosion. This threshold depends on two laser parameters, viz. beam spot size and wavelength. The larger the beam size and the longer the incident wavelength are, the higher is the laser irradiance required to cause phase explosion. 

The plasma threshold is the irradiance required to produce the optical breakdown of the vapour. It depends on the nature of the surface (particularly on various optical, thermophysical and thermodynamic properties of the material). The plasma threshold is usually higher than the ablation threshold. Observing optical emission entails applying more energy than that required to reach the plasma threshold. 

A striking feature of the results with y-rays, particularly in comparison with later experiments on other reactions, was the long irradiation required, perhaps 70 days for a reduction of the activity to one-half its original value (9). In contrast, the reactor irradiations which produced comparable reduction in activity were no more than 5 minutes at 4 x 10i fast neutrons cm sec i (iI5). A rough estimate of the dose rates... 

KrF) laser source allowed for uniform deposition across a 3" ( 7,5 cm) wafer. However, use of 193 nm (ArF) irradiation required dilution of the AlMe. concentration to avoid non-uniform film growth. 

Irradiation of multiple resonances is possible, but each resonance being irradiated requires the digitization of an additional FID. That is, the control FID can be used over and over by subtracting it from each digitized FID collected when a unique resonance is saturated. 

To inactivate feeder cells mitotically, use >5(X)0 rad of y irradiation. Alternatively, mitomycin C can be added to the medium at 10 Xg/mL and incubated in the 37°C incubator for 2-3 h. The cells are then washed very well with PBS (five changes of PBS), and trypsinized and plated as usnal. Both methods are equivalent, but irradiation requires an expensive and specialized machine, so most investigators use mitomycin C. It is important to take safety precautions with mitomycin C (wear gloves and a mask), since it is very toxic. 

Pasteurization and irradiation require a balance between minimizing undesirable organisms and retaining desirable characteristics of the food. 

Microwave irradiations require 10 min at 130 °C to get the product whereas the conventional method needs 60 min at 130 °C for the same process. The yield through the microwave method is 63-96 % whereas the conventional method gives 45-60% yield. 1,3,4-Oxadiazoles were prepared under microwave conditions by Burgess s reagent throngh the dehydration of unsymmetrical diarylhydroazines [58]. The prodnct was obtained in two steps in the presence of DMF and DCC in 5-10 min. The yield was 100%. The same reaction under conventional conditions required 90 min to form the product (Scheme 11.5). Rj was taken as alkyl or aiyl and R- was taken as -Cl or -OCH,. 

During this initial phase, it was found for static analysis that the high irradiance required for the FT-Raman analysis, to produce a satisfactory signal-to-noise ratio from the spectrum, led to the buildup of opaque impurities on the sampling window. Thus, it was necessary to construct a sample loop where material was pumped continuously pass the analysis point. Despite this precaution, the sample cell required periodic cleaning to remove impurity buildup [21]. 

Table 3.13 gives the doses of electron irradiation required for crystallographic effects in various polymers. The dose required for the destruction of crystallinity in linear PE is much larger than that for the other polymers, due to the fact that that radiation damage occurs preferentially within the amorphous regions of the material. 

Table 3.13 Doses of electron beam irradiation required for crystallographic effects in various polymers [23] ...

FIGURE 2.9 Duration of irradiation required depending on type of radiation for absorption of a defined energy dose D = 100 kGy [71 ]... 

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