6,615 research outputs found
Disorder-free sputtering method on graphene
Deposition of various materials onto graphene without causing any disorder is
highly desirable for graphene applications. Especially, sputtering is a
versatile technique to deposit various metals and insulators for spintronics,
and indium tin oxide to make transparent devices. However, the sputtering
process causes damage to graphene because of high energy sputtered atoms. By
flipping the substrate and using a high Ar pressure, we demonstrate that the
level of damage to graphene can be reduced or eliminated in dc, rf, and
reactive sputtering processes
An open reading frame upstream from the nifH gene of Klebsiella pneumoniae
An open reading frame upstream from nifHDK operon of Klebsiella pneumoniae had been described. The orientation of this open reading frame is opposite to that of nifHDK and sequence homology was found between the open reading frame promoter and the promoter of nifHDK operon. A recombinant plasmid carrying the promoter region of the open reading frame fused to the beta-galactosidase gene was constructed. Strains of E.coli were transformed with the plasmid containing this open reading frame promoter-lacZ fusion or co-transformed with it and a plasmid carrying the nifA gene. An appreciable activity of beta-galactosidase was found in strains which received both plasmids, indicating that the promoter of the open reading frame can be activated by the product of nifA gene. Thus, the open reading frame found between nifHDK operon and nifJ behaves just like other nif genes of K.pneumoniae in requiring the product of nifA as the positive effector for expression
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