Electric Current Curve Research Articles

Behavior in the electric current curve by changing the anodizing area

In this work, we studied the change in the electric current and the length of the nanotubes depending on the area and the exposure time in the anodizing process. Over time the anodizing area was changed with a rate of 0.5 cm2 to 2.5 cm2 using a total anodizing time of 60 min, using a chemical solution (2ml /3 ml /0.30g ) and maintaining a constant anodizing voltage equal to 20 V. The behavior in the nanostructures was recorded by the evolution of the current density as a function of the anodizing time. The morphology of the nanostructures was analyzed by means of scanning electron microscopy (SEM). With the use of the Imagej program. The size, length and diameter of the titanium nanostructures are obtained. The sample that presented the best behavior was that of an anodizing area of ​​1.5 cm2 and an anodizing time of 36 min. This presents a surface where open nanotubes are observed in the upper part with a vertical length of 0.23 μm and a pattern thereof organized in a circular arrangement with a diameter of 0.035 μm. It was observed that increasing the area under these anodizing conditions decreased the length of the nanotubes. The mobility of the loads was always greater with the area of ​​exposure, which is observed in the increase of the current

Absence of ferroelectricity in double-perovskite Y2CoMnO6 single crystals

The rare-earth double-perovskite R2CoMnO6 family has been reported to be promising multiferroics where the predicted ferroelectric polarization along the b-axis is induced by the Co2+/Mn4+ collinear magnetic order. In this work, we report our characterizations on the structural, magnetic, dielectric, and ferroelectric behaviors of flux-grown Y2CoMnO6 single crystals. A weak ferromagnetic transition with the Curie point TC ∼ 70 K is evident in combination with a remarkable magnetic hysteresis loop along the c-axis. The earlier reported dielectric anomaly at the magnetic transition is not detected in our single crystals. In addition, the peak of each electric current curve as a function of temperature, probed along different crystallographic directions, shows serious shifting with the temperature ramping rate, excluding the intrinsic ferroelectric contribution. The measured data are not in conformity with theoretical predictions and earlier experiments on polycrystalline samples. In addition, no reliable sign for magnetoelectric coupling can be detected. The present work seems to exclude the existence of magnetism-driven ferroelectricity in Y2CoMnO6.

Mixing‐Recording Method for the Practical Determination of Physical Properties of Soy Protein Isolate

The mixing properties of soy protein isolate (SPI) were investigated. The electric current of a kitchen food processor was monitored during the mixing of SPIs to produce dough, and an identical mixing curve was obtained for each SPI. The obtained peak time and peak height of the electric current curve were correlated to the physical properties (solubility and gel strength) of each SPI. The peak time negatively correlated with solubility, and the peak height positively correlated with gel strength. Optical microscopic observations showed that the dough microstructure appeared to be related to the peak time. Moreover, some conditions such as the SPI storage conditions and the ionic strength of the mixing buffer affected the mixing properties. This mixing‐recording method is proposed as a practical tool that could simplify the evaluation of SPI characteristics.

Current monitoring in a microchannel with repeated constrictions for accurate detection of sample location in isotachophoresis.

We present a new method for accurate detection of sample location in peak mode isotachophoresis (ITP). The technique is based on the design of a microchannel with multiple constrictions and on detecting the passage of the ITP interface through these constrictions. We achieve this by monitoring the electric current across the channel, which exhibits sharp decreases as the ITP interface moves more rapidly through the higher current density constrictions. We show that cross-correlation between the electric current signal and a predefined step function is an effective method for detecting changes in the slope of the electric current curve in real-time and is robust to changes in the composition of the buffers. We demonstrate the use of the technique to deliver sample to a designated location in the channel with an accuracy as low as 50 μm. Importantly, the method does not require the use of any optics and thus can be used to monitor the location of unlabeled species for application in a variety of ITP assays.

Time-Dependent Transport in Low-Dimensional Systems—A Numerical Solution Using the Nonequilibrium Green's Functions

In this paper, we present a novel numerical solution to analyze time-dependent transport in low-dimensional systems, such as one-dimensional (1-D) quantum dot and quasi-one-dimensional (Q1D) carbon nanotube systems, by using the nonequilibrium Green's functions (NEGF). The novelty of proposed approach is to jointly handle the NEGF in both the time-domain and the real-space-domain in a recursive fashion. The time-domain recursive approach is a straightforward approach to solve time-dependent transport problems, while the real-space recursive approach makes the calculations feasible for arbitrary-length 1-D and Q1D systems. To verify our proposed algorithm, we apply this method to explore the transient and ac transport properties of a sample 1-D quantum-dot array system. We will present in this paper the simulated electrical current curves, J (t), in response to various pulses and sinusoid waveforms. From these simulation results, we can obtain the delay and distortion information. We will then discuss how the length of a quantum-dot array and the hopping energy affect the transport behavior. The knowledge we gain from this project will help researchers to evaluate the electrical properties of 1-D and Q1D materials. The knowledge can also benefit the making of time-dependent 1-D and Q1D nanoelectronic devices

Very Low Dielectric Constants of Diamond-Like Carbon Films Deposited on Ground Electrode by Plasma-Enhanced Chemical Vapor Deposition

Hydrogenated diamond-like carbon (g-DLC:H) was deposited using methane (CH4) gas on p-type Si wafers on a grounded electrode using a plasma-enhanced chemical vapor deposition apparatus. The g-DLC:H films were of low dielectric constant <2.4ε0 proportional to the film thickness, and their densities and refractive indexes were approximately 1.25 g/cm3 and 1.56, respectively. Curves of dielectric constant for a sweep of bias voltages suggested the presence of electron traps in the g-DLC:H film near the interface between the g-DLC:H film and the Si substrate. Electric current curves for the sweep of bias voltages below 1.5 V can be approximated with the Poole–Frenkel mechanism showing the participation of traps in electron conduction. The electrical conductivities measured were proportional to the film thickness: the dielectric constant was proportional to the electrical conductivity. Thus, very low dielectric constants and large electrical conductivities for the g-DLC:H films were caused by electron traps, the densities of which varied with the film thickness.

Dynamic Molecular Reorientational Behavior Induced by Polarization Inversion of Ferroelectric Liquid Crystal

Abstract In order to clarify the rotational direction of molecular reorientation induced by a polarization inversion of ferroelectric liquid crystal (FLC), an electric current along the direction perpendicular to both an electric field and the smectic layer normal was measured for the first time for the FLC cell with a thickness of 50 μm. The electric current curve against time upon the application of an a.c. electric field with a form of triangular wave exhibited a peak attributed to a polarization inversion. The sign of the electric current peak value was inverted by the polarity inversion of an electric field, indicating that the LC molecules rotate in the same direction on the tilt cone upon polarity inversion, that is one-way rotation. The same result was given by polarizing optical microscope observation of the director change during the polarization inversion in a free-standing film. This result differs from that for a surface-stabilized FLC cell.