1,197 research outputs found
High Frequency Quantum Admittance and Noise Measurement with an On-chip Resonant Circuit
By coupling a quantum detector, a superconductor-insulator-superconductor
junction, to a Josephson junction \textit{via} a resonant circuit we probe the
high frequency properties, namely the ac complex admittance and the current
fluctuations of the Josephson junction at the resonant frequencies. The
admittance components show frequency dependent singularities related to the
superconducting density of state while the noise exhibits a strong frequency
dependence, consistent with theoretical predictions. The circuit also allows to
probe separately the emission and absorption noise in the quantum regime of the
superconducting resonant circuit at equilibrium. At low temperature the
resonant circuit exhibits only absorption noise related to zero point
fluctuations, whereas at higher temperature emission noise is also present.Comment: 15 pages, 15 figure
Quantum Noise Measurement of a Carbon Nanotube Quantum Dot in the Kondo Regime
The current emission noise of a carbon nanotube quantum dot in the Kondo
regime is measured at frequencies of the order or higher than the
frequency associated with the Kondo effect , with the Kondo
temperature. The carbon nanotube is coupled via an on-chip resonant circuit to
a quantum noise detector, a superconductor-insulator-superconductor junction.
We find for a Kondo effect related singularity at a
voltage bias , and a strong reduction of this singularity
for , in good agreement with theory. Our experiment
constitutes a new original tool for the investigation of the non-equilibrium
dynamics of many-body phenomena in nanoscale devices.Comment: 6 pages, 4 figure
Phylloquinone (vitamin K 1 ) biosynthesis in plants: two peroxisomal thioesterases of lactobacillales origin hydrolyze 1,4âdihydroxyâ2ânaphthoylâcoa
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/1/TPJ_4972_sm_FigS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/2/TPJ_4972_sm_TableS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/3/TPJ_4972_sm_FigS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/4/TPJ_4972_sm_TableS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/5/TPJ_4972_sm_FigS6.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/6/j.1365-313X.2012.04972.x.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/7/TPJ_4972_sm_FigS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/8/TPJ_4972_sm_TableS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/9/TPJ_4972_sm_FigS5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/10/TPJ_4972_sm_TableS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/92396/11/TPJ_4972_sm_FigS4.pd
High kinetic inductance microwave resonators made by He-Beam assisted deposition of tungsten nanowires
We evaluate the performance of hybrid microwave resonators made by combining sputtered Nb thin films with Tungsten nanowires grown with a He-beam induced deposition technique. Depending on growth conditions, the nanowires have a typical width w [35 - 75] nm and thickness t [5 - 40] nm. We observe a high normal state resistance R [65 - 150] Ω / which together with a critical temperature T c [4 - 6] K ensures a high kinetic inductance making the resonator strongly nonlinear. Both lumped and coplanar waveguide resonators were fabricated and measured at low temperature exhibiting internal quality factors up to 3990 at 4.5 GHz in the few photon regime. Analyzing the wire length, temperature, and microwave power dependence, we extracted a kinetic inductance for the W nanowire of L K 15 pH / which is 250 times higher than the geometrical inductance, and a Kerr non-linearity as high as K W, He / 2 Ï = 200 ± 120 Hz / photon at 4.5 GHz. The nanowires made with the helium focused ion beam are thus versatile objects to engineer compact, high impedance, superconducting environments with a mask and resist free direct write process
Automatic ROI detection and classification of the Achilles tendon ultrasound images
Ultrasound (US) imaging plays an important role in medical
imaging technologies. It is widely used because of its ease of use
and low cost compared to other imaging techniques. Specifically,
ultrasound imaging is used in the detection of the Achilles Tendon
(AT) pathologies as it detects important details. For example, US
imaging is used for AT rupture that affects about 1 in 5,000
people worldwide. Decision support systems are important in
medical imaging, as they assist radiologist in detecting probable
diagnoses and lesions. The work presented in this paper concerns
the development of a software application to detect changes in the
AT ultrasound images and subsequently classify them into normal
or abnormal. We propose an approach that fully automates the
detection for the Region of Interest (ROI) in ultrasound AT
images. The original image is divided into six blocks with 1 cm
size in each direction. The blocks lie inside the vulnerable area
considered as our ROI. The proposed system achieved an
accuracy of 97.21%
Metabolic reconstructions identify plant 3âmethylglutaconylâCoA hydratase that is crucial for branchedâchain amino acid catabolism in mitochondria
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/144600/1/tpj13955_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/144600/2/tpj13955.pd
Exploring tandem ruthenium-catalyzed hydrogen transfer and SNAr chemistry
A hydrogen-transfer strategy for the catalytic functionalization of benzylic alcohols via electronic arene activation, accessing a diverse range of bespoke diaryl ethers and aryl amines in excellent isolated yields (38 examples, 70% average yield), is reported. Taking advantage of the hydrogen-transfer approach, the oxidation level of the functionalized products can be selected by judicious choice of simple and inexpensive additives
Dynamics of a small neutrally buoyant sphere in a fluid and targeting in Hamiltonian systems
We show that, even in the most favorable case, the motion of a small
spherical tracer suspended in a fluid of the same density may differ from the
corresponding motion of an ideal passive particle. We demonstrate furthermore
how its dynamics may be applied to target trajectories in Hamiltonian systems.Comment: See home page http://lec.ugr.es/~julya
Patterned Irradiation of YBa_2Cu_3O_(7-x) Thin Films
We present a new experiment on YBa_2Cu_3O_{7-x} (YBCO) thin films using
spatially resolved heavy ion irradiation. Structures consisting of a periodic
array of strong and weak pinning channels were created with the help of metal
masks. The channels formed an angle of +/-45 Deg with respect to the symmetry
axis of the photolithographically patterned structures. Investigations of the
anisotropic transport properties of these structures were performed. We found
striking resemblance to guided vortex motion as it was observed in YBCO single
crystals containing an array of unidirected twin boundaries. The use of two
additional test bridges allowed to determine in parallel the resistivities of
the irradiated and unirradiated parts as well as the respective current-voltage
characteristics. These measurements provided the input parameters for a
numerical simulation of the potential distribution of the Hall patterning. In
contrast to the unidirected twin boundaries in our experiment both strong and
weak pinning regions are spatially extended. The interfaces between
unirradiated and irradiated regions therefore form a Bose-glass contact. The
experimentally observed magnetic field dependence of the transverse voltage
vanishes faster than expected from the numerical simulation and we interpret
this as a hydrodynamical interaction between a Bose-glass phase and a vortex
liquid.Comment: 7 pages, 8 Eps figures included. Submitted to PR
- âŠ