Figure 4. Optical transmission micrographs of annihilated spirals having opposite rotation directions (a) and common organizing center (b). Carbon film thickness is the same as in Figure 3.At present the complexity of the phenomenon studied makes difficult an unambiguous explanation of the general mechanism involved. Nevertheless, different processes, as for example specific carbon thin film growth phenomena, cracks generation resulting from internal stresses, or thermally induced crystallization, could be supposed. Further experiments which are in progress will help for a better understanding of the intimate mechanism of spiral formation.
ConclusionSummarizing the results obtained, it should be noted that the present study gives the first experimental evidence of spirallike structure formation in the system: thin films of amorphous carbon/silicate glass. The appearance of such structures as a sequence of mass-energy flow through the system, the presence of spirals with topological charge equal or greater than unity, and the annihilation of two wave fronts are essential characteristics of the investigated process. It seems that this is not an unique case taking into account the results published on other solid-state thin-film systems. 16-1 * On this basis the formation of spiral structures in the system reported could be attributed to the more general self-organization phenomena.Acknowledgment. This work has been completed with the financial support of Bulgarian Ministry of Education and Science under Contract No. X-23/ 15.10.1991. We are highly obliged to Dr. Andrey Milchev (Institute of Physical Chemistry, Bulgarian Academy of Sciences) for stimulating discussions. Registry No. Carbon, 7440-44-0. References and Notes (1) Zhabotinski, A. M. In Oscillations and traueling waves in chemical systems; Field, R. J., Burger, M., Eds.; Mir: Moskow, 1988; p (16) Monev, M.; Rashkov, St.; Kaischev, R. Surf. Technol. 1982,17,315. (17) Aivazov, A. A.; Bodyagin, N. V.; Vikhrov, S. P.; Petrov, S. V. J. Non-Cryst. Solids 1989, 114, 157. (18) Bagratashvili, V. N.; Banishev, A. F.; Gnedoy, S. A.; Emelyanov, V. I.; Seminogov, B. N.; Merzlyakov, K. S.; Panchenko, V. Ya.; Zherikhin, A. N. Pouerkn.-Fiz. Chim. Mech. 1991, 2, 115 (in Russian). Certificate 1989, No. 84027.The pibility that Cu-Y zeolites are dealuminated during reduction with H2 (at 473 K) or with CO (at 773 K) was investigated by XRD and by 29Si and 27Al MAS NMR. H2/02 and CO/O2 cycles were also examined. Stoichiometric determinations of the oxidation and reduction steps were determined separately to compare the chemistry occurring using CO or H2 as the reducing agents. Although some dealumination was detected under certain conditions, the amount was much less than that required to charge-balance the lattice on the conversion of Cu2+ to Cu+. Evidence is presented that extralattice oxygen is introduced during the preparation steps.