Macrocyclic 10-mesityl-1,8-diphenylanthracene dimer 4 was synthesized by using the electron-transfer oxidation of Lipshutz cuprate derived from 1,8-bis(4-bromophenyl)-10-mesityl-anthracene 7 in moderate yield. This dimer 4 is a considerably fluorescent molecule (Φ 0.40) with high thermal, photo, and air stability. The X-ray analysis of 4 revealed a unique structure with a small inner cavity which can incorporate a small molecule or atom. H NMR spectra in solution and emission spectra of 4 in the solid state showed that copper(I) ion was incorporated to form a 1:1 complex 4·CuOTf, whereas silver(I) ion only weakly interacted with 4 under similar conditions.
A model of overload effect for hardening elastic-plastic solids is proposed to evaluate the stress intensity factor for compressive residual stress K rs at fatigue crack-tip fields. The residual stress rs introduced at the tip in SUS316 by overload K ov = 6, 15, 30 and 45 MPam 1/2 can be estimated using Finite Element Method (FEM). The K rs values as a function of fatigue crack growth length a were calculated from the rs according to Dugdale model. It was found that the calculated K rs decreased significantly with increasing a and reached to maximum value of |K rs |. Therefore, the maximum stress intensity factor K max will decrease apparently because of the action of K rs. As a result, effective stress intensity factor range given by K eff = K max +K rs decreased with increasing a. Defining the fatigue crack cannot grow when K eff = K th , the apparent fatigue crack growth threshold K th can be estimated. Then, we can obtain the theoretical equation as K th =0.30K ov +4.10. The equation showed in good agreement with experimental results.
The effects of overload on the threshold stress intensity factor (K ISCC ) for stress corrosion cracks (SCC) in type 304 austenitic stainless steel (SUS304) were studied. Tensile overload was applied to a wedge opening loaded specimen of SUS304, and SCC tests were carried out to determine the resultant K ISCC . The values of K ISCC were found to increase with increasing stress intensity caused by tensile overload. Comparison of the effects of tensile overload on K ISCC of SUS304 and SUS316 revealed that the effects of overload on K ISCC of SUS304 was smaller than that of SUS316. Both K th and K ISCC can be predicted by the similar equation considering the effects of overload.
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