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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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Journal ArticleDOI
TL;DR: Colicin E1 belongs to a group of bacteriocins whose cytotoxicity toward Escherichia coli is exerted through formation of ion channels that depolarize the cytoplasmic membrane, and the lipid dependence of colicin single-channel conductance demonstrated intimate involvement of lipid in the structure of this channel.

68 citations

Journal ArticleDOI
TL;DR: A series of fused porphyrin oligomers for which the conductance increases substantially with length by >10-fold at a bias of 0.7 V is reported, indicating that this large increase in conductance with length at increasing voltages can be generalized to other molecular oligomers.
Abstract: A key goal in molecular electronics has been to find molecules that facilitate efficient charge transport over long distances. Normally, molecular wires become less conductive with increasing length. Here, we report a series of fused porphyrin oligomers for which the conductance increases substantially with length by >10-fold at a bias of 0.7 V. This exceptional behavior can be attributed to the rapid decrease of the HOMO–LUMO gap with the length of fused porphyrins. In contrast, for butadiyne-linked porphyrin oligomers with moderate inter-ring coupling, a normal conductance decrease with length is found for all bias voltages explored (±1 V), although the attenuation factor (β) decreases from ca. 2 nm–1 at low bias to <1 nm–1 at 0.9 V, highlighting that β is not an intrinsic molecular property. Further theoretical analysis using density functional theory underlines the role of intersite coupling and indicates that this large increase in conductance with length at increasing voltages can be generalized to ...

68 citations

Journal ArticleDOI
TL;DR: The general observation is made that conductance increases rather dramatically at higher tilt angle away from the normal for conformationally rigid molecular wires and that this increase in conductance arises from increased electronic coupling between the molecular bridge and the gold contacts.
Abstract: It is now becoming clear that the characteristics of the whole junction are important in determining the conductance of single molecules bound between two metal contacts. This paper shows through measurements on a series of seven conjugated molecular bridges that contact separation is an important factor in determining the electrical response of the molecular junction. These data are obtained using the I(t) method developed by Haiss et al since the scanning tunnelling microscope tip to substrate separation can be controlled through choice of the set-point (I0) current and calibrated with current–distance curves and knowledge of the terminal to terminal length of the molecular wire. The contact gap separation dependence is interpreted as arising from tilting of these molecules in the junction and this model is underpinned by ab initio transport computations. In this respect we make the general observation that conductance increases rather dramatically at higher tilt angle away from the normal for conformationally rigid molecular wires and that this increase in conductance arises from increased electronic coupling between the molecular bridge and the gold contacts.

68 citations

Journal ArticleDOI
TL;DR: The effect of extracellular pH changes on the voltage—current relation of frog muscle membrane has been studied using intracellular microelectrodes using rubidium to reduce the cation conductance of the membrane.
Abstract: 1. The effect of extracellular pH changes on the voltage—current relation of frog muscle membrane has been studied using intracellular microelectrodes. To reduce the cation conductance of the membrane, potassium in Ringer solution was replaced by rubidium. 2. When the relatively impermeant methyl sulphate ion replaced extracellular chloride the membrane conductance was low, time independent and little influenced by extracellular pH changes. The voltage—current relation was linear at both high and low pH values. 3. In rubidium Ringer solution at pH 7·4 the membrane conductance fell as the inside of the fibre was made more negative, in a manner consistent with the predictions of the constant field theory. 4. At a high pH value (9·8) the resting conductance was high, but it fell steeply as the membrane potential was increased; for large hyperpolarizing voltages the membrane current tended to a limiting value. The voltage—current relation crossed those recorded at pH 7·4 and 5·0. 5. In acid Ringer solution (pH 5·0) the resting membrane conductance was low and remained constant until the membrane potential was hyperpolarized more than 30 mV beyond the resting value; the conductance then rose as the membrane potential was further increased. For large hyperpolarizations the membrane conductance was higher at pH 5·0 than at pH 9·8. 6. Experiments using two successive, identical, constant current pulses suggested that the membrane conductance altered during the passage of current across the membrane; in alkaline solution the conductance fell with time, in acid solution it rose. 7. Because no time or voltage dependence of the membrane conductance was seen in the absence of chloride ions it is inferred that the movements of chloride ions across the muscle membrane are responsible for both the time and voltage dependent alterations in membrane conductance seen at different pH values.

68 citations

Journal ArticleDOI
TL;DR: In this paper, the frequency dependent of the forward and reverse bias capacitance-voltage (C-V) and conductance voltage (G/WV) measurements of Al/SiO"2/p-Si (MIS) structures are carried out in frequency range of 10kHz-10MHz.

68 citations


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