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1.
Rev Sci Instrum ; 83(8): 083704, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22938300

RESUMO

We demonstrate a new and simple process to fabricate tungsten tips with good control of the tip profile. In this process, we use a commercial function generator without any electronic cutoff circuit or complex mechanical setup. The tip length can be varied from 160 µm to 10 mm, corresponding to an aspect ratio of 1.6-100. The radius of curvature of the tip apex can be controlled to a size <10 nm. Surface roughness and the taper angle can be controlled independently. Through control of the etching parameters, the tip length, the radius of curvature, surface roughness, and the taper angle can be controlled to suit different requirements of various applications. The possible etching mechanisms are also discussed.

2.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 6): o1725, 2012 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-22719513

RESUMO

In the title compound, C(15)H(13)N(3)O(4), the dihedral angle between the benzene rings is 3.1 (3)°. The mol-ecule displays an E conformation about the C=N bond. In the crystal, mol-ecules are linked via N-H⋯O hydrogen bonds, generating chains that propagate along the b-axis direction. There is also a C-H⋯O inter-action present.

3.
Acta Crystallogr Sect E Struct Rep Online ; 68(Pt 5): o1352, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22590247

RESUMO

The title compound, C(14)H(11)N(3)O(4), was obtained by a condensation reaction between 3-nitro-benzaldehyde and 4-hy-droxy-benzohydrazide. The whole mol-ecule is approximately planar, with a dihedral angle of 9.2 (3)° between the benzene rings. The mol-ecule displays an E conformation about the C=N bond. In the crystal, mol-ecules are linked via N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds, generating sheets parallel to the bc plane.

4.
J Nanosci Nanotechnol ; 11(12): 10687-90, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22408974

RESUMO

Two kinds of new nano tips with potential to magnetic application are fabricated. One is a PtCo alloy pyramidal tip formed by surface faceting, the other is a Pt based Co tip formed by the epitaxy with a proper growth mode. Ultra high vacuum-field ion microscopy with atomic resolution is used to investigate the atomic structures of the tip apex after various sharpen treatments.

5.
Nanotechnology ; 20(33): 335701, 2009 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-19636091

RESUMO

We report a reliable method for preparing a pure Ir single-atom tip by thermal treatment in oxygen. The atomic structure of the tip apex and its ion emission characteristics are investigated with field ion microscopy. We have shown that the Ir single-atom tip can be a good field ion emitter, capable of emitting a variety of gas ion beams, such as He+, H2+, N2+, and O2+, with high brightness and stability. In addition, this tip can easily be maintained and regenerated in vacuum, ensuring it has sufficient lifetime for practical applications.

6.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 4): o851, 2009 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-21582569

RESUMO

The title compound, C(15)H(12)BrClN(2)O(3), was obtained by the condensation reaction between 3-bromo-5-chloro-2-hydroxy-benzaldehyde and 2-methoxy-benzohydrazide. The mol-ecule is essentially planar, with a dihedral angle between the two benzene rings of 4.7 (2)°, and displays an E configuration about the C=N double bond. The mol-ecular conformation is stabilized by intramolecular O-H⋯N and N-H⋯O hydrogen bonds. In the crystal structure, mol-ecules are linked into zigzag chains running parallel to the c axis by inter-molecular C-H⋯O hydrogen bonds. The chains are further connected through aromatic π-π stacking inter-actions with centroid-centroid distances of 3.583 (4) Å.

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