Acid present after irradiation

The analysis of acid present before irradiation was determined to be 2 x 10 6 mmol for a one micrometer films on a 2 inch wafer. This is a significant fraction of total acid present after irradiation. For a 0.5 mJ/cm2 dose, this is nearly 30% of the total acid content. However, the acid present before exposure is not significant for t-BOC thermolysis. No carbonyl infrared absorbance change was noted following softbake. 

Acid generation in photoresist films add photogeneration vs. dose, 3233/ acid present after irradiation, 32,34r add present before irradiation, 32 quantum yield, 3234 Acid hardening resin resists cross-linking adivation energy determination, 87,89 cross-linking chemistry, 87 determination of acid generated, 87-88 effect of postexposure bake temperature and time, 87... 

Moore [355] used the solvent extraction procedure of Danielson et al. [119] to determine iron in frozen seawater. To a 200 ml aliquot of sample was added lml of a solution containing sodium diethyldithiocarbamate (1% w/v) and ammonium pyrrolidine dithiocarbamate (1 % w/v) at pH to 4. The solution was extracted three times with 5 ml volumes of 1,1,2 trichloro-1,2,2 trifluoroethane, and the organic phase evaporated to dryness in a silica vial and treated with 0.1 ml Ultrex hydrogen peroxide (30%) to initiate the decomposition of organic matter present. After an hour or more, 0.5 ml 0.1 M hydrochloric acid was added and the solution irradiated with a 1000 W Hanovia medium pressure mercury vapour discharge tube at a distance of 4 cm for 18 minutes. The iron in the concentrate was then compared with standards in 0.1 M hydrochloric acid using a Perkin-Elmer Model 403 Spectrophotometer fitted with a Perkin-Elmer graphite furnace (HGA 2200). 

Nucleic acids can be visualized on the slab gel after separation by soaking in a solution of ethidium bromide, a dye that displays enhanced fluorescence when intercalated between stacked nucleic acid bases. Ethidium bromide may be added directly to the agarose solution before gel formation. This method allows monitoring of nucleic acids during electrophoresis. Irradiation of ethidium bromide-treated gels by UV light results in orange-red bands where nucleic acids are present. 

After irradiation with 3.3 MGy of a DCH18C6 solution in 1 mol L 1 nitric acid containing 20 g I. of uranyl nitrate, compounds 2 and 4 (presented in Figure 8.15 with their radiolytic yields) were shown to be the main products of radiolysis nevertheless, 50% of DCH18C6 remained unchanged. In these conditions, the disappearance yield G(-DCH18C6) was estimated to be 0.72 molecule/100 eV (7). 

Maize starch may be separated after irradiation into several fractions, based on solubility in alcohol and aqueous alcohol. The size of the fractions and their composition depends on the radiation dose, as shown in Table X which also shows the distribution of organic products of destruction (aldehydes and carboxylic acids) in particular fractions.118 The relations presented in this Table are S-shaped. Under irradiation with increasing doses, the destruction of starch obviously increases. The nature of the increase of acidity in com starch has also been studied by Athanassiades and Berger.119 Thollier and Guilbot120 have conducted similar studies on potato starch, and Raffi et al99 have extended their studies to more varieties of starch. The results expressed as free and total acidities, as well as the quantity of formic acid at equilibrium water content, are given in Table XI. These data vary rather nonlinearly with increase of the irradiation dose and water content. 

The present results confirm that the doublets observed in the e.s.r. spectra of several carboxylic acids immediately after X- or y-irradiation at 77°K are due to the radical anions of the acid. Further it is reasonable to assume that a similar sequence of reactions to that postulated above occurs in the formation of radicals in carboxylic acids by high energy irradiation. Thus the radical anion is the primary product and the more stable free radicals are formed subsequently by hydrogen abstraction by the anion from a neighbouring acid molecule. 

The photolysis of dialkylphenacylsulfonium salts and dialkyl-4-hydroxyphenyl-sulfonium salts is different from that of triphenylsulfonium salts. The latter compounds undergo irreversible photoinduced carbon-sulfur bond cleavage the former compounds, however, react by reversible photodissociation and form resonance-stabilized ylids as shown in Fig. 5. Because of the slow thermally induced reverse reaction, only small equilibrium concentrations of the ylid and acid arc present during irradiation and the concentration will rapidly decrease when photolysis has been terminated. Therefore, in contrast to triarylsulfonium salt initiation, no dark reaction will continue after the irradiation step. 

Figure 7. ESR spectra of radicals derived from N-acetyl-iL-alanine in an irradiated D20 ice plug. Sample contained 190 mg/ml of N-acetylalanine and was irradiated to 5 kGy at —196°C. Spectrum a was recorded at —196°C spectra b and c at —135°C. All spectra have markers from Fremys salt superimposed. (a) Composite spectrum of radicals present after annealing at —153°C (approximately 65% corresponds to the anion), (b) Composite spectrum of the radicals formed upon annealing the ice plug to — 80°C, of which 55% corresponds to the fatty acid radical, -CH(CHS)C02. (c) Spectrum of the peptide radical, CHsC0NDC(CHs)C02, formed upon further annealing the ice plug...

Cupric chloride and ferrous ammonium sulfate were then successfully used as inorganic inhibitors to prevent homopolymerization in the liquid phase. Films were sealed in 50% acrylic acid aqueous solution saturated with the inorganic inhibitor under nitrogen gas and irradiated with y-rays at a dose rate of 0.13 Mrad/hr at room temperatures. After irradiation, the films were washed with water. The results are presented in Figure 6. The weight increase varied linearly with dose. The rate of grafting with ferrous ammonium sulfate was higher than that with cupric chloride. 

The sample solution is not analyzed for C, as opposed to H, since it can be assumed that the total inventory of this radionuclide in the fuel sample is converted to the volatile compounds CO2, CO, and CH4 in the course of the dissolution reaction. This assumption was confirmed by parallel investigations in which C was determined by dry ignition of the fuel sample in air the results obtained by this technique showed good agreement with those obtained after acid dissolution, which led to the conclusion that no C compounds are present in irradiated fuel which are stable in boiling nitric acid. 

It is known that terl-butyl esters of carboxylic acids thermally decompose to form carboxylic acids and isobutene (id). The thermal decomposition temperature is lower if strong acids are present (id). Figure 5 shows FT-IR spectral changes of PMOBH film containing 3.6 mol% FITS on irradiation. After irradiation of the film with a dose of 180 mJ/cm at room temperature, no significant changes in the FT-IR spectrum were observed though the film became insoluble in THF. When the irradiated film was baked at 90 C for 10... 

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