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Conductance

About: Conductance is a research topic. Over the lifetime, 8088 publications have been published within this topic receiving 235961 citations.


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TL;DR: The boundary conditions for the Riccati distribution functions at a spin-active interface were derived in terms of an interface $S$-matrix describing the reflection and transmission of the normal state conduction electrons by the interface as mentioned in this paper.
Abstract: The Riccati formulation of the quasiclassical theory of nonequilibrium superconductors is developed for spin-dependent scattering near magnetic interfaces. We derive boundary conditions for the Riccati distribution functions at a spin-active interface. The boundary conditions are formulated in terms of an interface $S$-matrix describing the reflection and transmission of the normal-state conduction electrons by the interface. The $S$-matrix describes the effects of spin filtering and spin mixing (spin rotation) by a ferromagnetic interface. The boundary conditions for the Riccati equations are applicable to a wide range of nonequilibrium transport properties of hybrid systems of superconducting and magnetic materials. As an application we calculate the spin and charge conductance of a normal metal-ferromagnet-superconductor (NFS) point contact; the spin mixing angle that parameterizes the $S$-matrix is determined from experimental measurements of the peak in the subgap differential conductance of the NFS point contact. We also use the new boundary conditions to derive the effects of spin mixing on the phase-modulated thermal conductance of a superconducting-ferromagnetic-superconducting (SFS) point contact. For high-transparency (metallic ferromagnet) ``$\ensuremath{\pi}$'' junctions, the phase modulation of the thermal conductance is dramatically different from that of nonmagnetic, ``0'' junctions. For low-transparency (insulating ferromagnet) SFS tunnel junctions with weak spin-mixing resonant transmission of quasiparticles with energies just above the gap edge leads to an increase of the thermal conductance, compared to the normal-state conductance at ${T}_{c}$, over a broad temperature range when the superconducting phase bias is $\ensuremath{\phi}\ensuremath{\gtrsim}\ensuremath{\pi}∕2$.

74 citations

Journal ArticleDOI
TL;DR: Theoretical considerations indicate that the coupling between β-cells within the islet is sufficient to allow propagation of [Ca2+]i waves to spread with a speed of approximately 80 μm s−1, similar to that observed experimentally in confocal [Ca 2+] i imaging.
Abstract: The perforated whole-cell configuration of the patch-clamp technique was applied to functionally identified b-cells in intact mouse pancreatic islets to study the extent of cell coupling between adjacent b-cells. Using a combination of current- and voltage-clamp recordings, the total gap junctional conductance between b-cells in an islet was estimated to be 1.22 nS. The analysis of the current waveforms in a voltage-clamped cell (due to the firing of an action potential in a neighbouring cell) suggested that the gap junctional conductance between a pair of b-cells was 0.17 nS. Subthreshold voltage-clamp depolarization (to K55 mV) gave rise to a slow capacitive current indicative of coupling between b-cells, but not in non-b-cells, with a time constant of 13.5 ms and a total charge movement of 0.2 pC. Our data suggest that a superficial b-cell in an islet is in electrical contact with six to seven other b-cells. No evidence for dye coupling was obtained when cells were dialysed with Lucifer yellow even when electrical coupling was apparent. The correction of the measured resting conductance for the contribution of the gap junctional conductance indicated that the whole-cell KATP channel conductance (GK,ATP) falls from approximately 2.5 nS in the absence of glucose to 0.1 nS at 15 mM glucose with an estimated IC50 of approximately 4 mM. Theoretical considerations indicate that the coupling between b-cells within the islet is sufficient to allow propagation of [Ca 2C ]i waves to spread with a speed of approximately 80 m ms K1 , similar to that observed experimentally in confocal [Ca 2C ]i imaging.

74 citations

Journal ArticleDOI
TL;DR: Sodium silicate based thermal interface pastes give higher thermal contact conductance across conductor surfaces than polymer based pastes and oils, due to their higher fluidity and the consequent greater conformability.
Abstract: Sodium silicate based thermal interface pastes give higher thermal contact conductance across conductor surfaces than polymer based pastes and oils, due to their higher fluidity and the consequent greater conformability. Addition of hexagonal boron nitride particles up to 16.0 vol. percent further increases the conductance of sodium silicate, due to the higher thermal conductivity of BN. However, addition beyond 16.0 vol. percent BN causes the conductance to decrease, due to the decrease in fluidity. At 16.0 vol. percent BN, the conductance is up to 63 percent higher than those given by silicone based pastes and is almost as high as that given by solder. Water is almost as effective as sodium silicate without filler, but the thermal contact conductance decreases with time due to the evaporation of water. Mineral oil and silicone without filler are much less effective than water or sodium silicate without filler. @S1043-7398~00!00402-3#

73 citations

Journal ArticleDOI
TL;DR: In this article, the frequency dependent capacitance-voltage and conductancevoltage properties of metal-ferroelectric-insulator-semiconductor (MFIS) structures were investigated by considering series resistance (R"s) and surface state effects in the frequency range of 1kHz-5MHz.

73 citations

Journal ArticleDOI
TL;DR: Using a scanning tunneling microscope, high-bias conductance of single polyporphyrin molecular wires with lengths from 1.3 to 13 nm is measured and first-principles simulations revealed that the measured conductance is coherent resonant transport via a delocalized molecular orbital.
Abstract: Using a scanning tunneling microscope, we measured high-bias conductance of single polyporphyrin molecular wires with lengths from 1.3 to 13 nm. We observed several remarkable transport characteristics, including multiple sharp conductance peaks, conductances as high as 20 nS in wires with lengths of >10 nm, and nearly length-independent conductance (attenuation <0.001 A–1). We carried out first-principles simulations on myriad metal–molecule–metal junctions. The simulations revealed that the measured conductance is coherent resonant transport via a delocalized molecular orbital.

73 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023457
2022828
2021154
2020158
2019172
2018168