192 research outputs found
Spin effects in single-electron transport through carbon nanotube quantum dots
We investigate the total spin in an individual single-wall carbon nanotube
quantum dot with various numbers of electrons in a shell by using the ratio of
the saturation currents of the first steps of Coulomb staircases for positive
and negative biases. The current ratio reflects the total-spin transition that
is increased or decreased when the dot is connected to strongly asymmetric
tunnel barriers. Our results indicate that total spin states with and without
magnetic fields can be traced by this method.Comment: 5pages, 5figures, accepted for publication in Phys. Rev.
Introducing Nonuniform Strain to Graphene Using Dielectric Nanopillars
A method for inducing nonuniform strain in graphene films is developed.
Pillars made of a dielectric material (electron beam resist) are placed between
graphene and the substrate, and graphene sections between pillars are attached
to the substrate. The strength and spatial pattern of the strain can be
controlled by the size and separation of the pillars. Application of strain is
confirmed by Raman spectroscopy as well as from scanning electron microscopy
(SEM) images. From SEM images, the maximum stretch of the graphene film reaches
about 20%. This technique can be applied to the formation of band gaps in
graphene.Comment: Appl. Phys. Express, in pres
Giant High-Flow Type Pulmonary Arteriovenous Malformation: Coil Embolization with Flow Control by Balloon Occlusion and an Anchored Detachable Coil
Pulmonary arteriovenous malformations (PAVMs) are often treated by pushable fibered or non-fibered microcoils, using an anchor or scaffold technique or with an Amplatzer plug through a guiding sheath. When performing percutaneous transcatheter microcoil embolization, there is a risk of coil migration, particularly with high-flow type PAVMs. The authors report on a unique treatment in a patient with a giant high-flow PAVM whose nidus had a maximum diameter of 6 cm. A detachable coil, not detached from a delivery wire (an anchored detachable coil), was first placed in the feeding artery under flow control by balloon occlusion, and then multiple microcoils were packed proximally to the anchored detachable coil. After confirming the stability of the microcoils during a gradual deflation of the balloon, we finally released the first detachable coil. The nidus was reduced in size to 15 mm at one year postoperatively
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