Theoretical Study On The Dislocations In The Bubble Rafts

Soap bubbles is our daily life to common things, but they contain many esotericphysics problem, which cause the attention of many physicists. As the kelvin said:"ifyou blow a bubble and watch it, you can spend the whole life to study on it, then youwill obtain many physical laws." The landmark building of Beijing Olympic Gameswater cube building inspiration comes from the research achievements of soap bubbles’shape and mechanics study.In1934，dislocation model has been put out, which solve the problem that thetheoretical calculation of the shear strength value about1000times higher than thevalue of experiments measurement, and this problem had plagued the physicist longtime. But without direct experimental observation, the problem that whether there reallyis a dislocation existing in crystal has been controversial, and some scientists have asceptical view on dislocation theory. Bragg and Nye in1947used soap solution producea two-dimensional bubble raft constitute by a large number of the same radius soapbubbles, and one can clearly see defects in it such as grain boundaries and dislocations.The bubble raft provide a powerful proof to confirm that there is a dislocation in crystalindeed. Bubbles raft model has been widely applied in several areas, but there is not asystem method to calculate the core structure of dislocation in bubble rafts, so finding aeffective method to discuss the dislocation in bubule rafts is very necessary.P-N model is a classic dislocation model, which is one of important methods to thestudy the core structure of dislocations. But because it did not make full considerationof the discrete effect to dislocations, while the discrete effect to the core structure ofdislocations in bubble rafts is very significant, and the force-law between bubbles isvery complex, sine force is no longer applicable, therefore, it is difficult to obtain theprecise dislocation core structure from the traditional P-N model.In recent years, the author’s teacher has established lattice theory of dislocationon the basis of dynamic and P-N model. The theory fully consider the effect of discretelattice, and provied an improved dislocation equation, which contains correction ofdiscrete effect, it has applied to discuss the dislocation of iron, silicon, and graphene andthe result is very good.Through solving improved dislocation equation, this paper obtain the dislocationcore structure of bubble rafts with radius0.296mm,0.592mm， and0.888mm, and the results of0.650mm is good agreement with experimental data. Form the calculatedresults of the core width, one can see, with the decreased in radius of soap bubbles, thecore width of bubble rafts become wider quickly. In addition, we also discuss thediscrete correction influence on the dislocation in bubble rafts, and found that the radiusof the bubbles biger, the greater discrete correction effect.