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The transient current, electrical conductivity, dielectric constant ( ε′), and dielectric loss factor ( ε″) of starch and methylcellulose homopolymers and their blends with various compositions were studied under different conditions. The x-ray diffraction pattern was obtained for individual polymers and 50:50 wt/wt% blend sample to identify both the structure and degree of crystallinity. From transient current, the ionic and electronic transfer number as well as charge carrier density and drift mobility were determined. The values of activation energy in the temperature range 30-90 °C indicate that the conduction mechanism is due to combined electronic and ionic processes, while in the temperature range 100-160 °C, electronic contribution is predominant. The complex dielectric data of the present samples in an extended frequency and temperature range appear as different relaxation processes, which are connected with polymer dynamics. [ABSTRACT FROM AUTHOR]

Abstract: We previously reported that dipoles on the surface of the gate insulator layer in organic transistors cause time decay of the drain current on time scales of less than 0.1s from the application of the gate voltage. In this study, we investigated the relationship between the time decay and magnitude of the gate voltage. We found that this time decay can be attributed to threshold voltage shifts unaccompanied by mobility changes. When the insulator surface has dipoles that can move somewhat, the threshold voltage shift has two components: one with a time scale of approximately 0.1s and the other with a time scale of tens of minutes. [Copyright &y& Elsevier]

Abstract: An investigation into the transient current at the disc electrode is presented in this paper. Two boundary conditions on the disc are considered: the disc has a uniform concentration over its area, and the disc exhibits a charge transfer (irreversible reaction). The principle of scale analysis is used to determine both the short and long time asymptotic behaviour. Compact and accurate expressions are proposed to evaluate the transient current regardless of the time scale. A relevant correlation method is used for this purpose. The results show an excellent agreement with available works for the uniform concentration and the charge transfer cases respectively. [Copyright &y& Elsevier]

Electro-osmotically driven displacement between two solutions having a conductivity mismatch is theoretically examined. Internal pressures induced by the conductivity mismatch can affect the propagation of the solution interface and the behavior of the transient current. Combining Ohm's law and fluid mass conservation, we derive a coupled set of length-averaged equations accounting for how the electric current and the traveling distance of the solution interface vary with time, electric field, and the solution conductivities. Extension to successive displacements involving multiple solution zones is made to reveal non-monotonic and stagewise changes in transient currents. For the first time, critical roles of surface conductance on displacements in highly charged channels are unraveled. We show that if the lower conductivity solution has a greater valence than the higher one, the effective conductivity of the former can exceed that of the latter when the channel height is below some critical value. The resulting transient current behavior can turn opposite to that usually observed in the large-channel case, offering a new paradigm for gauging the importance of surface conductance in submicron charged channels. Possible impacts of diffusion smearing and hydrodynamic dispersion are also discussed by including the additional mixing zone into the analysis. Having shown good agreement with the existing experimental data, our analysis not only captures the natures of solution displacement by electro-osmotic flow (EOF), but also extends the applicability of the current monitoring method for measuring surface zeta potentials of microchannels. [ABSTRACT FROM AUTHOR]

Experimental results showing angular dependence for charge collection in SOI transistors under heavy ion irradiation are presented. Geant4 and Synopsys Sentaurus simulations are performed to analyze these results in terms of direct ionization effects. The influence of the beam direction in relation to that of the transistor's channel on the transistor's response is underlined. Depending on the considered beam direction, deviation from the inverse-cosine law is shown to vary from 0% to 30%. These differences seem to be independent of the ion energy. However, the use of different ion species may hide this possible effect. [ABSTRACT FROM AUTHOR]

We investigate the transient electron transport through the quantum dot and double quantum dot systems coupled with the time-dependent barriers to infinitely large reservoirs of noninteracting electrons. Time-dependent currents and quantum dot occupancies are calculated using both nonequilibrium Green's functions formalism and the equation of motion method for appropriate correlation functions. We show that the sequence of ultrafast modulation of the tunneling amplitudes between the electron reservoirs and the quantum dots can induce quite different electron occupation of the quantum dot in comparison with the static case. We also find that the oscillations of the transient current following the sudden coupling of the electron reservoirs with the double quantum dot system have the same frequency as Rabi's oscillations of the double dot state vector. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic field effects on cuprous oxide cathodic electrodeposition from alkaline cupric lactate solution have been investigated at 70°C by electrochemical and physical techniques. Stationary analyses exhibit a tenuous decrease of the plateau electrolytic current as the magnetic field increases. Due to the limited diffusion process of the hydroxide species which reacts during the electrochemical process, a magnetically induced effect can be suspected but deposition of Cu2O that covers the electrode and “passivates” the surface leads to antagonist effects that explain the current decrease. For a cathodic applied potential corresponding to the current plateau, X-ray diffraction studies reveal the formation of single phase cubic Cu2O films with or without magnetic field, but a change in electrocrystallization kinetics of Cu2O is observed in the presence of the magnetic field. Analyses of the transient current curves reveal a convective effect of the magnetic field from the very first moments of the electrocrystallization. [Copyright &y& Elsevier]

R&D activities have been carried out for decades by many researchers in order to improve electromechanical contactor performance employing electronic control. This includes electronic controlled contactor opening to minimize contact erosion, and closing to reduce contact bounce, but the improvement is limited with significant increase of cost and size due to the inherent design structure of contactors: simultaneously switching of all three poles. Meanwhile, solid-state motor starters have shown great benefit with point-on-wave (POW) switch-on to minimize transient current and torque .stress of induction machines during motor starting process. However, cost and size is a premium. A novel technology that employs asynchronous modular concept and POW switching has been developed. .This improves motor starting and contactor switching performances in respect to switching transients and contact erosion while utilizing small size and low cost electromechanical contactors. These contactors are assembled into a flexible modular contactor assembly that allows each pole to be switched independently with precise POW switching control. This paper will focus on motor starting applications to achieve significant reduction of motor starting transients and contactor switching capability improvement. Asynchronous modular contactor prototypes with newly developed 24-VDC controlled contactors have been developed. The evaluation tests of the prototype proved significant transient current and torque stress reduction during motor starting. [ABSTRACT FROM AUTHOR]

Abstract: Intracloud (IC) and cloud-to-ground (CG) lightning flashes produce transient changes in the electric field (E) above a thundercloud which drive transient currents in the global electric circuit (GEC). Using in-cloud and above-cloud E data from balloons, ground-based E data, and Lightning Mapping Array data, the above-cloud charge transfers due to lightning transients are estimated for five IC and five CG flashes from four thunderstorms that occurred above the mountains in New Mexico, USA, in 1999. For the five CG flashes (which transferred −4 to −13 C to the ground), the transient currents moved +1 to +5 C of charge upward from cloudtop toward the ionosphere, with an average transient charge transfer of about 35% of the charge transferred to ground. For the five IC flashes (which neutralized 6 to 21 C inside the cloud), the transient currents moved −0.7 to −3 C upward, with an average transient charge transfer of about 12% of the lightning charge. Estimates for three thunderstorms indicate that the transient currents made only a small GEC contribution compared to the quasi-stationary Wilson currents because of the offsetting effects of IC and CG flashes in these storms. However, storms with extreme characteristics, such as high flash rates or predominance of one flash type, may make a significant GEC contribution via lightning transients. [Copyright &y& Elsevier]

Abstract: Nanocrystals-based memories are promising candidates for the scaling of Flash memories in the next decade. However, tools to specify where the carriers are actually stored are still needed in order to optimize the elaboration processes of the nanocrystals. This article presents a model which may be used to extract the physical parameters of the objects in which the carriers are charged. These parameters are extracted from transient current measurements which may be performed by most conventional static ammeters. The model is based on the study of an equivalent circuit followed by a finite elements analysis of the memory device. This technique has been used to study MOS capacitors containing silicon nanocrystals obtained by annealing LPCVD silicon rich oxide layers. Our model was found to predict all the transient features observed in the current. It quantitatively determined that in average, one electron is charged into 3–5 nm diameter nanocrystals having a density of 0.84–1.5×1012 cm−2. These parameters are very close to the size and the density which have been targeted during the elaboration process. [Copyright &y& Elsevier]

Abstract: Effects of the Leslie viscosity coefficients α i (i =1, 2, …, 5) of nematic liquid crystals (NLCs) with negative dielectric anisotropy (Δε <0) on the electric-field-induced director reorientation in homeotropic NLC cells have been studied from the analysis of the transient current induced by step voltage application. The transient current in a homeotropic NLC cell with Δε <0 was well reproduced by computer simulation, based on the theory of NLCs in which the flow effects and the free-slip boundary condition are taken into account. It is found that the response time of vertical alignment NLC displays is dominantly governed by α 2 and α 4 + α 5 of NLCs with Δε <0. [Copyright &y& Elsevier]

Abstract: The dopamine (DA) transporter (DAT) is a major molecular target of the psychostimulant amphetamine (AMPH). AMPH, as a result of its ability to reverse DAT-mediated inward transport of DA, induces DA efflux thereby increasing extracellular DA levels. This increase is thought to underlie the behavioral effects of AMPH. We have demonstrated previously that insulin, through phosphatidylinositol 3-kinase (PI3K) signaling, regulates DA clearance by fine-tuning DAT plasma membrane expression. PI3K signaling may represent a novel mechanism for regulating DA efflux evoked by AMPH, since only active DAT at the plasma membrane can efflux DA. Here, we show in both a heterologous expression system and DA neurons that inhibition of PI3K decreases DAT cell surface expression and, as a consequence, AMPH-induced DA efflux. [Copyright &y& Elsevier]

In this paper, we propose a method for testing CMOS domino circuits using the transient power supply current. The method is based on monitoring and processing the transient current. We evaluate the effectiveness of this testing method through simulations of various domino circuits of different sizes. Moreover, we propose a normalising technique to mask the process variations effect associated with current testing. Furthermore, we present a test vector generation algorithm for testing large domino circuits, and develop and implement a clustering technique to improve the fault coverage of the test method when used with large circuits. The clustering algorithm divides the circuit into different clusters where each cluster is fed by a different power supply branch. [ABSTRACT FROM AUTHOR]

In this paper, we present a critical evaluation of the influence of geometry on the behavior of the transient current at all ultramicroelectrodes. The nonsteady-state chronoamperometric diffusion limited current of various microelectrodes (circular disc, circular ring, elliptical disc, elliptical ring, band, hemicylinder, hemisphere, hemioblate and hemiprolate electrodes) are compared. Here, the area of the entire electrode is fixed and time variables are also normalized with respect to area. The chronoamperometric current for short and long time for all microelectrodes are given in tabular as well as graphical form also. [ABSTRACT FROM AUTHOR]

Abstract: The steady-state and non-steady-state diffusion-limited currents for EC′ reactions for all ultramicroelectrodes (circular disc, circular ring, elliptical disc, elliptical ring, band, hemisphere, hemicylinder, hemi-oblate and hemi-prolate electrodes) are compared. In this paper we present a critical assessment of the influence of geometry on the behavior of the transient current. In the research presented here, the surface area of all the electrodes was fixed. The chronoamperometric currents for all times and for all K values are given in tabular and graphical form. [Copyright &y& Elsevier]

The role of ion track structure on high-injection carrier dynamics in a high-speed GaAs p+ - n - n+ sensor is investigated using laser and high-energy heavy ion microbeams. The results are compared to similar data collected on a Si p+ - n - n+ device where Space Charge Screening Effects (SCSE) result in transient shape being dependent on ion track structure. The results collected are discussed within the framework of the Edmonds charge collection model and generalized to III-V optoelectronic sensors. [ABSTRACT FROM AUTHOR]

Temperature effects on the electric characteristics were studied in a colloidal system made up of 0.05-wt.% multiwalled carbon nanotubes dispersed in the nematic liquid crystal E7. The electric properties were observed via measurement of transient current in a homogeneously aligned liquid-crystal cell induced by a polarity-reversed field. The cell filled with the suspension and that containing pristine liquid crystal exhibited similar voltage- and temperature-dependent behaviors in the experiments. However, it was interestingly found that the transient current originating from the transport of impurity ions was remarkably suppressed in the suspension. The enhancement of the ionic mobility was also observed in such a colloidal system. [ABSTRACT FROM AUTHOR]

Abstract: The polarization response of the Buried OXide (BOX) in UNIBOND Fully Depleted MOSFETs is investigated by means of a modified drain current DLTS setup. The investigation is based on the transient analysis that indicates the presence of dipolar relaxation as well as polarization processes related to interface charge trapping. The BOX dielectric relaxation shows the presence of both Debye and complex relaxation processes. The coupling between gate modulation and BOX polarization is also considered. [Copyright &y& Elsevier]

Cerebellar Purkinje neurons in vivo exhibit high frequency and multi-spike action potentials with transient (INaT), resurgent (INaR) and persistent (INaP) Na+ currents arising from voltage-gated Na+ channels, which play important roles in shaping the action potentials and electrical activity of these cells. However, little is known about Na+ channel expression in cultured Purkinje neurons despite the use of in vitro approaches to study these cells. Therefore, GFP-expressing Purkinje neurons isolated from transgenic mice were analysed after four weeks in culture, when, coincident with distinct axonal and dendritic morphologies, cultured Purkinje neurons exhibited dendrite-specific MAP2 expression characteristic of polarized neurons. In cell-attached patch clamp recordings, Na+ currents occurred at significantly higher frequencies and amplitudes in patches from the soma and axon than from dendrites, similar to the polarized distribution observed in vivo. INaT, INaR and INaP Na+ currents with properties similar to those observed in acutely isolated Purkinje neurons were detected in nucleated outside-out patches from cultured Purkinje cells. RT-PCR analysis detected Nav1.1, Nav1.2 and Nav1.6, but not Nav1.3, Nav1.4, Nav 1.5 or Nav1.8 Na+ channel α subunit gene expression in cultured Purkinje neurons, as observed in vivo. Together, the results indicate that key aspects of Na+ channel expression in mature Purkinje neurons in vivo occur in vitro. [ABSTRACT FROM AUTHOR]

The statistical transient response of floating body SOI and bulk devices is measured under proton and heavy ion irradiation. The influence of the device architecture is analyzed in detail for several generations of technologies, from 0.25 μm to 70 nm. The effects of the measured transients on SET sensitivity are investigated. The amount of collected charge and the shape of the transient currents are shown to have a significant impact on the temporal width of propagating transients. Finally, based on our measured data, the threshold LET and the critical transient width for unattenuated propagation are calculated for both bulk and floating body SOI as a function of technology scaling. We show that the threshold LETs and the critical transient widths for bulk and floating body SOI devices are similar. Body ties can be used to harden SOI ICs to digital SET. However, the primary advantage of SOI technologies, even with a floating body design, mostly lies in shorter transients, at a given ion LET, for SOI technologies than for bulk technologies. [ABSTRACT FROM AUTHOR]

The transient Ca2+ and Ca2+-dependent Cl− currents in the plasma membrane of voltage-clamped cells of the freshwater alga Chara corallina were studied. We used our own earlier proposed method, which utilized a rapid (∼10 ms) injection of Ca2+ ions into the cell during the deactivation period of calcium channels after their activation with a positive voltage pulse (injection with a “tail” Ca2+ current). This procedure makes it possible to determine the amplitude of the Ca2+ component in the transient current as well as the amplitude and kinetics of the Cl− component, dependent on the Ca2+ submembrane concentration. The calculated results, which used a cell model that takes the diffusion of Ca2+, the Ca2+-buffering properties of the cytoplasm, and the nonlinear dependence of i Cl on [Ca2+]cyt, as well as the presence of chloroplasts into account, were in good agreement with the actual behavior of transient current in the experiments. It was demonstrated that the duration of the slow stage of [Ca2+]cyt relaxation to the resting level (∼10−7 M) (which is related to the function of Ca2+-ATPases), was ∼102 s. This suggests that the slow stage determines the duration of the refractory period after generation of the action potential. [ABSTRACT FROM AUTHOR]

We propose a field-emission device surrounded by high-k dielectric (FESH) that used a Spindt-type emitter; its design guidelines are demonstrated using various device parameters. The most significant aspect of the FESH structure is its use of high-k dielectric material to surround the emitter. The large dielectric constant of the high-k dielectric dramatically reduces the threshold voltage when applying dc voltage. It is shown that the most suitable device parameters can be extracted from the viewpoint of figure-of-merit. When dc voltage is applied to a FESH device, a large transient current flows between the anode and the cathode. The application of an ac voltage eliminates the current leakage that would otherwise hinder the development of practical applications such as displays. It is demonstrated from dynamic simulations that sinusoidal input pulses should be applied to FESH devices rather than rectangular input pulses since the former realizes the benefits of low-power operation and high reliability [ABSTRACT FROM PUBLISHER]

Abstract: Electrically charged species in nonaqueous media still hold many questions. Recent studies and applications show the need for a better understanding of the origin and nature of these charged species. Transient current measurements have been used to study the conductivity of nonaqueous liquid containing charged inverse micelles. At small time scales (1–100 ms) drift and diffusion of charged species are the main contributions to the measured current. At larger timescales (above 1 s) a nonzero quasi steady-state current at high voltages (above 0.5 V) remains. This indicates that besides drift and diffusion an additional process occurs. The dependence of the quasi steady-state current on the applied voltage, micelle concentration, and device thickness has been investigated. Experimental results have been compared to simulations and analytical calculations. It is concluded that the quasi steady-state current results from a bulk disproportionation reaction between neutral micelles that generates charged micelles. And therefore this technique allows for direct quantification of the reaction kinetics from which the charged species originate. [Copyright &y& Elsevier]

This paper investigates the transient response of 50-nm gate length fully and partially depleted SOI and bulk devices to pulsed laser and heavy ion microbeam irradiations., The measured transient signals on 50-nm fully depleted devices are very short, and the collected charge is small compared to older 0.25-μm generation SOI and bulk devices. We analyze in detail the influence of the SOI architecture (fully or partially depleted) on the pulse duration and the amount of bipolar amplification. For bulk devices, the doping engineering is shown to have large effects on the duration of the transient signals and on the charge collection efficiency. [ABSTRACT FROM AUTHOR]

Pb 1.1 (Zr 0.30 Ti 0.70 ) O 3 (PZT) and Pb 1.1 (Zr 0.30 Ti 0.70 ) O 3 /PbTiO 3 (PZT/PT) multi-layered thin films are grown on Pt/Ti/SiO 2 /Si substrate by sol-gel method. The kinetics of current change of pyroelectric and transient response between PZT and PZT/PT ferroelectric thin films is investigated. The shape of peak in the PZT film is sharp, but that of PZT/PT is broadened. An increase in the peak value of switching current and switching time in the PZT/PT film is observed. The change of pyroelectric and transient current between PZT/PT and PZT films is discussed in terms of internal field. [ABSTRACT FROM AUTHOR]

The analysis of transient currents in Au/PLZT/LSCO gate-capacitor structure has been used to determine the distribution of surface traps at the F/S interface. The total charge associated with the surface states recharge under the bias variation was found to be Q1 ∼ 3 μC/cm², which is far less than the remnant polarization at the operating bias values. [ABSTRACT FROM AUTHOR]

Single MeV ion induced currents are directly responsible for a wide range of single event phenomena leading to temporary or permanent malfunction of devices in radiation environments such as space. The active regions of a device act as a source of transient currents injected into a device subsystem by collecting the charge induced by MeV ions. As such, the charge collection process is an important step in understanding mechanisms that lead to device malfunction. In this paper, we present transient current data collected on Si epilayer devices with 15 MeV O4+ ions focused using a MeV heavy ion micro-probe. The measured transient currents are compared to quasi-3D simulation using ISE TCAD software. Critical factors influencing the fidelity of the measurement technique and modeling of heavy ion track models are also discussed. [Copyright &y& Elsevier]

The role of nitrogen in the mechanisms of localized corrosion resistance and repassivation were electrochemically investigated using a nitrogen-bearing austenitic stainless (SUS316L) steel in 0.1 and 0.5 M Na2SO4 solutions and a 3.5% NaCl solution. Almost 100% of the nitrogen compounds dissolved into the bulk solution after crevice corrosion were transformed into NH3. That is, the mole amount of ammonia in the solution was approximately equivalent to the mole amount of nitrogen dissolved in the steel. This suggests that NH4+ consuming H+ in the pit controlled the local decrease of pH and promoted the repassivation. NO3–N and NO2–N were not detected by chemical analyses in the high potential and thermodynamically stable zone as NO3− in the potential–pH diagram. The repassivation in nitrogen-bearing SUS316L steel in a 0.1 M Na2SO4 solution was studied using the scratching electrode technique, which measured the partially destroyed passivation films on the steel. This technique showed that nitrogen dissolved in the steel has a strong repassivation capacity. [ABSTRACT FROM AUTHOR]