ELECTRON TRANSPORT MECHANISM IN COBALT POLYMETHACRYLATE (CoPMA)

1991 ◽  
Vol 05 (29) ◽  
pp. 1933-1938 ◽  
Author(s):  
M.H. CHOHAN ◽  
A.H. KHALID ◽  
M. ZULFIQAR ◽  
P.K. BUTT ◽  
FARAH KHAN ◽  
...  
Keyword(s):  
Electron Transport ◽  
Transport Mechanism ◽  
Conduction Mechanism ◽  
Electronic Conduction ◽  
Strong Temperature Dependence ◽  
Transport Mechanisms ◽  
Electrical Measurements ◽  
Current Voltage ◽  
Current Voltage Relationship ◽  
Voltage Relationship

Electron transport mechanisms in cobalt polymethacrylate have been investigated. The electrical measurements made on the polymer, show that the current-voltage relationship at lower voltages (V<300 V) is ohmic whereas at higher voltages it is exponential. The strong temperature dependence of current on voltage indicates the dominance of a Poole-Frenkel mechanism and the existence of trapping levels. Low activation energy values suggest an electronic conduction mechanism.

Irregular Electron Transport Through a-Si:H Based Potential Barriers

1993 ◽  
Vol 297 ◽  
Author(s):  
Norbert Bernhard ◽  
B. Frank ◽  
B. Movaghar ◽  
G.H. Bauer
Keyword(s):  
Electron Transport ◽  
Transport Mechanism ◽  
Current Transport ◽  
Transport Mechanisms ◽  
Potential Barriers ◽  
Resonant Tunnelling ◽  
Current Voltage ◽  
Different Temperatures ◽  
Current Voltage Characteristics ◽  
Stable Formation

Irregularities in the current-voltage-characteristics of a-Si:H based potential barriers have been investigated experimentally, and are discussed theoretically with respect to different transport mechanisms. The investigated samples were different series of double and single barrier a-Si:H - a-Si1-xCx:H - heterostructures, as well as homogeneous samples without heterostructure barrier. Current-voltage-(I-V)-characteristics showing a wide variety of features, from complete smoothness of the curves, to bumps and even accidental step-like switching behaviour, as well as different forms of noise, were recorded at different temperatures. Resonant tunnelling as an explaining transport mechanism for the anomalies was excluded because of inconsistency between experiment and calculations partially including special amorphous features. Instead it is argued that all observed irregularities, i. e. bumps in I-V-curves, switching-like behaviour, and appearance of noise, are related to current transport via trap-assisted tunnelling through locally strongly confined transport paths, leading to the meta-stable formation, change and break-down of conductory filaments.

Carrier Transport in Porous Silicon Light-Emitting Diodes

1994 ◽  
Vol 358 ◽  
Author(s):  
C. Peng ◽  
P.M. Fauchet ◽  
K.D. Hirschman ◽  
S.K. Kurinec
Keyword(s):  
Porous Silicon ◽  
Layer Thickness ◽  
Chemical Treatment ◽  
Carrier Transport ◽  
Transport Mechanisms ◽  
Light Emitting ◽  
Current Voltage ◽  
Device Structures ◽  
Current Voltage Relationship ◽  
Voltage Relationship

ABSTRACTThis work presents a systematic investigation of carrier injection and transport mechanisms in light emitting porous silicon (LEPSI). In addition to optical characterization of the LEPSI film, the electrical characteristics of LEPSI light emitting diodes (LEDs) and the device parameter effects on electroluminescence (EL) efficiency are explored including junction structure, LEPSI layer thickness, and chemical treatment. Au/LEPSI device structures exhibit a power-law current-voltage relationship (I∼Vm) and LEPSI pn junction device structures exhibit an exponential current-voltage relationship (I∼eeV/nkT). The carrier transport mechanisms are discussed, and theoretical simulations match well with the experimental data. An increase in EL efficiency has been achieved by adjusting the LEPSI layer thickness, implementing chemical treatment, and improving the quality of the contacts. The EL response to the frequency modulation of LEPSI LEDs was studied, resulting in a cutoff frequency in excess of 100 kHz. LEPSI LEDs have demonstrated stable EL at applied voltages as low as 5 volts with EL efficiencies of 0.01%.

scholarly journals Plasticity of calcium-permeable AMPA glutamate receptors in Pro-opiomelanocortin neurons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Shigetomo Suyama ◽  
Alexandra Ralevski ◽  
Zhong-Wu Liu ◽  
Marcelo O Dietrich ◽  
Toshihiko Yada ◽  
...  
Keyword(s):  
Food Deprivation ◽  
High Fat Diet ◽  
Receptor Complex ◽  
High Fat ◽  
Fasted State ◽  
Linear Current ◽  
Current Voltage ◽  
Relationship Of ◽  
Current Voltage Relationship ◽  
Voltage Relationship

POMC neurons integrate metabolic signals from the periphery. Here, we show in mice that food deprivation induces a linear current-voltage relationship of AMPAR-mediated excitatory postsynaptic currents (EPSCs) in POMC neurons. Inhibition of EPSCs by IEM-1460, an antagonist of calcium-permeable (Cp) AMPARs, diminished EPSC amplitude in the fed but not in the fasted state, suggesting entry of GluR2 subunits into the AMPA receptor complex during food deprivation. Accordingly, removal of extracellular calcium from ACSF decreased the amplitude of mEPSCs in the fed but not the fasted state. Ten days of high-fat diet exposure, which was accompanied by elevated leptin levels and increased POMC neuronal activity, resulted in increased expression of Cp-AMPARs on POMC neurons. Altogether, our results show that entry of calcium via Cp-AMPARs is inherent to activation of POMC neurons, which may underlie a vulnerability of these neurons to calcium overload while activated in a sustained manner during over-nutrition.

Capsaicin and nicotine both activate a subset of rat trigeminal ganglion neurons

1996 ◽  
Vol 270 (6) ◽  
pp. C1807-C1814 ◽  
Author(s):  
L. Liu ◽  
S. A. Simon
Keyword(s):  
Trigeminal Ganglion ◽  
Acetylcholine Receptors ◽  
Ganglion Cells ◽  
Whole Cell Patch Clamp ◽  
Current Voltage ◽  
Trigeminal Ganglion Neurons ◽  
Ganglion Neurons ◽  
Relationship Of ◽  
Current Voltage Relationship ◽  
Voltage Relationship

Nicotine and capsaicin produce many similar physiological responses that include pain, irritation, and vasodilation. To determine whether neuronal nicotine acetylcholine receptors (nAChR) are present on capsaicin-sensitive neurons, whole cell patch-clamp recordings were performed on rat trigeminal ganglion cells. It was found that approximately 20% of the total number of neurons tested was activated by both 100 microM nicotine and 1 nM capsaicin. Other subsets of neurons were activated by only one of these compounds, whereas a fourth subset was not activated by either compound. At -60 mV, the magnitude of the capsaicin-activated currents was about three times larger than the magnitude of the nicotine-activated currents. The current-voltage relationship of the nAChR exhibited marked rectification, such that for voltages > or = 0 mV the current was essentially zero. In contrast, the current-voltage relationship of the capsaicin-activated current was ohmic from +/- 60 mV. These data indicate the existence of subsets of capsaicin-sensitive afferent neurons.

Simulation of Na/K Pump Current-Voltage Relationship

1992 ◽  
Vol 671 (1 Ion-Motive AT) ◽  
pp. 449-451 ◽  
Author(s):  
X.-Y. LIU ◽  
T. A. KINARD ◽  
J. R. STIMERS
Keyword(s):  
Pump Current ◽  
Current Voltage ◽  
Current Voltage Relationship ◽  
Voltage Relationship

scholarly journals Ionic Basis of Membrane Potential and of Acetylcholine-evduced Currents in the Cell Body of the Cockroach Fast Coxal Depressor Motor Neurone

1990 ◽  
Vol 151 (1) ◽  
pp. 21-39 ◽  
Author(s):  
JONATHAN A. DAVID ◽  
DAVID B. SATTELLE
Keyword(s):  
Cell Body ◽  
Outward Current ◽  
Motor Neurone ◽  
Resting Potential ◽  
Inward Current ◽  
Current Voltage ◽  
Low K ◽  
Current Voltage Relationship ◽  
Ionic Basis ◽  
Voltage Relationship

The ionic basis of the resting potential and of the response to acetylcholine (ACh) has been investigated in the cell body membrane of the fast coxal depressor motor neurone in the metathoracic ganglion of the cockroach Periplaneta americana. By means of ion-sensitive microelectrodes, intracellular concentrations of three ion species were estimated (mmoll−1): [K+]i, 1443; [Na+]i, 9±1; [Cl−], 7±1. The resting potential of continuously superfused cells was −75.6±1.9mV at 22° C. A change in resting potential of 42.0±2.5mV accompanied a decade change in [K+]o. Experiments with (10−4moll−1) ouabain, Na+ injection, low temperature (10°C) and non-superfused cells indicated the presence of an electrogenic sodium pump. Under current-clamp, the cell body membrane was depolarized by sequentially applied, ionophoretic pulses (500ms duration) of ACh. Under voltage-clamp, such doses of ACh resulted in an inward current which was abolished in low-Na+ saline. Ion-sensitive electrodes revealed an increase in [Na+]i but no change in [Cl−1]j in response to externally applied ACh. The ACh-induced current-voltage relationship was shifted in a negative direction by low-K+ saline. The AChinduced inward current was usually followed by a delayed outward current which reversed at Ek. Low-K+ saline had the same effect on this outward component as depolarizing the membrane. This suggests that the outward current component is carried by K+. The ACh-induced inward current and the delayed outward current were potentiated either when [Ca2+]i was lowered by injecting the calcium chelator BAPTA or by exposure of the cell to low-Ca2+ saline. High-Ca2+ saline reduced the inward component of the response and produced a negative shift in the AChinduced current-voltage relationship. The amplitude of the delayed outward

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