The purposes of this work are to prepare a low density carbon nanofiber (CNF) emitter by a spray spreading method and to investigate the performance of field emission. A sprayed paste was prepared with organic solution of tetrahydrofuran and also with binders of Au paste and Polycarbonate. The used CNF were massively synthesized by a thermal chemical vapor deposition and were burned to eliminate amorphous carbon and catalyst The diameter ofthe CNF was about 0.1 Jlmcjl. Two types ofCNF were studied with the length of ea. 10-20 J.llD. (normal-CNF) and ea. 1.5 Jlffi (cut-CNF). In the normal-CNF emitter the current density at 10 V/J.UD. was about 1.4mA/cm 2 with an electric field enhancement factor~ of about 1000, while 0.08mA/cm 2 with ~ of 4500 in the cut-CNF emitter. It was confirmed that the isolated CNF do play an important role as effective emitter sites.
In this paper we give an exact analytic solution for tachyon condensation in the modified (picture 0) cubic superstring field theory. We prove the absence of cohomology and, crucially, reproduce the correct value for the D-brane tension. The solution is surprising for two reasons: First, the existence of a tachyon vacuum in this theory has not been definitively established in the level expansion. Second, the solution vanishes in the GSO(−) sector, implying a "tachyon vacuum" solution exists even for a BPS D-brane.
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