Application Of Direct Current Voltage Research Articles

Study on TBAB hydrate nucleating activity of electrode products due to DC voltage application

The effect of the products obtained by applying a direct current (DC) voltage to electrodes on the nucleation of tetra-n‑butyl ammonium bromide (TBAB) hydrate was investigated experimentally. Six kinds of materials were used as electrodes and the products were generated by applying a DC voltage to the electrodes in a TBAB aqueous solution at a normal temperature. The nucleating activities of the products were estimated by measuring the freezing probability of the TBAB aqueous solution containing the products. High probabilities of freezing were obtained for the Zn, Cu, and Ag electrodes. Moreover, the insoluble products were separated from the TBAB solution after a DC voltage was applied to the Zu, Cu, and Ag electrodes. The products were placed in a clear TBAB aqueous solution and the freezing probability of the TBAB solution was measured. The products had a high nucleating activity for TBAB hydrate.

Improving the sensitivity of miniature linear ion trap mass spectrometer by a DC voltage applied on the eject electrodes.

A miniaturized linear ion trap mass spectrometer with continuous atmospheric pressure interface has been built in our lab. Significant extension in mass range and reduction in power consumption have been realized by the supplemental alternating current frequency scan mode. However, relatively poor sensitivity has been witnessed, which is directly dominated by the detection efficiency of the ion detector. Theoretical analysis has been implemented to find ways to improve the detection efficiency. The results show that enhanced sensitivity can be obtained by applying a direct current voltage on the pair of electrodes in eject direction. Experiments show that the sensitivity has been improved by more than one time due to the application of direct current voltage. With this design, this homemade miniature linear ion trap mass spectrometer can be used to analyze more rarefied samples, especially to on-site chemical analysis and space application.

Tribological performance of TiN coatings deposited on 304 L stainless steel used for olive-oil extraction

Titanium-nitride (TiN) coatings have been developed and used by industry in numerous tribological applications, including machining, manufacturing and transportation. However, they have not attracted any attention as a tribological coating to be used in olive-oil extraction devices. In fact, since the separation of vegetation water and solid phase of the olive is always made in a continuous process and in very short time, the wear damage of the metallic devices used in this process is still a serious problem. The purpose of this study is to investigate the mechanical and tribological behaviors of TiN coating under a wide range of deposition conditions. The results of this study have confirmed that the coatings deposited using direct current (DC) bias present several distinct changes compared to those produced with pulse bias, depending on the magnitude of the duty cycle applied with and without Argon gas. Besides, different grain orientations have been detected for both kinds of TiN coatings. Tribological performances for the obtained TiN coatings were investigated using different configurations namely reciprocating sliding and pin-on-disk tests. The responses of these coatings in terms of friction coefficient and wear depth were discussed. The main results when sliding against olive seed and alumina ball as counterbody have clearly revealed a significant improvement of tribological properties with the application of DC and pulse bias voltage. Moreover, the tribological behavior of TiN did not change much with the addition of Ar gas.

Characteristics of hydrophobicity loss on silicone rubber surface during a dynamic drop test with direct current voltage application

Dynamic drop test for studying the temporal lowering of hydrophobicity on the surface of silicone rubber with direct current voltage application was carried out. In this study, we evaluated the influence of the temporal lowering of hydrophobicity under various conductivities and dropping rates for water droplets. As a result, it was found that the dropping rate and the conductivity of water droplets greatly influenced the hydrophobicity loss time on the surface of silicone rubber.

Hydrogen gas production from olive mill wastewater by electrohydrolysis with simultaneous COD removal

Diluted olive mill wastewater (OMW) was subjected to direct current (DC) voltages (0.5–4.0 V) for hydrogen gas production with simultaneous chemical oxygen demand (COD) removal by electrohydrolysis. The highest cumulative hydrogen production (3020 ml) and hydrogen yield (2500 ml H 2 g −1 COD) were obtained with 3 V DC voltage while the highest current intensity (80 mA), percent hydrogen (95%) in the gas phase, hydrogen gas formation rate (614 ml d −1), percent COD removal (44%) and energy conversion efficiency (95%) were realized with 2 V. Hydrogen gas production by electrolysis of water was negligible for all voltages. COD removal from OMW with no DC voltage application was usually lower than that obtained with DC power application. Hydrogen gas production by electrohydrolysis of OMW was proven to be a fast and effective method with simultaneous COD removal.

Behavior of ion affecting image sticking on liquid crystal displays under application of direct current voltage

Image sticking can be observed in some cases and it degrades the image quality of liquid crystal (LC) display. The image sticking is considered to be induced by generation of residual direct current voltage (Vrdc), which would be caused by the presence of ion in a LC cell. We clarified the generation mechanism of Vrdc based on a model of adsorption and desorption of the ion to and from the surface of an alignment layer at various temperatures. The experimental results indicate that these processes can be explained by the Boltzmann distribution. The analysis based on Arrehnius plots shows that the ion adsorbs to the surface of the alignment layer with weak binding such as van der Waals interaction or hydrogen bonding. This finding is effective for development of high image quality LC displays.

Highly Aligned Growth of Carbon Nanotubes by RF-Plasma-Assisted DC Plasma Chemical Vapor Deposition at High Pressure

Very highly aligned carbon nanotubes (CNTs) were synthesized by radio-frequency-plasma-assisted direct current (DC) plasma chemical vapor deposition, which was developed for the large-area growth of highly aligned CNTs under a stable condition in a DC plasma. Three parallel electrodes, namely, an RF electrode, a grounded electrode, and a DC cathode, were arranged in a vacuum chamber. It was found that the application of a high DC voltage at a high pressure forms a high sheath electric field, resulting in the highly aligned growth of CNTs without severe damage.

Effects of electric potential on chemical-mechanical polishing of copper

The effect of electric potential on the dissolution and polishing behavior of copper in acidic and alkaline media was investigated. The electromechanical polishing mechanism of copper is discussed based on removal rate of copper, pH of slurries, and surface morphology of polished copper. The most interesting phenomenon occurred in chemical-mechanical polishing (CMP) of copper with applied direct current (DC) voltage is the variation of pH during polishing. The dissolution experiments indicated that an acidic agent might have more hydrogen reduced with higher DC potential. The results demonstrated that the application of DC voltage is beneficial to improve planarization of copper polishing in an alkaline slurry.

Image amplification with local addressing by two-wave coupling in a Bi_12SiO_20 crystal by application of direct-current voltage

We present a proposal and an analysis of local image amplification by two-wave coupling in a Bi12SiO20 crystal by applying external dc voltage. The analogy of two-wave coupling to an optical transistor array is discussed. It is found through the experiments that the local gain in amplification is given not by the reference-beam pattern alone but also by the electric field that is formed by the local photoconductance of the Bi12SiO20 crystal. A resistance-network model is used for analysis of the electric-field distribution. A variety of experiments verify the theoretical and calculated analyses. A sample reference pattern for amplifying segments of a signal image is designed through the resistance-network analysis of the electric-field distribution.