Faraday Cage Research Articles

Comparative study of the hydrophobic interaction effect of pH and ionic strength on aggregation/emulsification of Congo red and amyloid fibrillation of insulin

Amyloid fibrillation is provoked by the conformational rearrangement of its source. In our previous study, we claimed that the conformational rearrangement of hen egg white lysozyme requires intermolecular aggregation/packing induced. Our proposed causality of the aggregation and amyloid formation was demonstrated by the quantitative dependence of amyloid fibrillation on pH difference from its isoelectric point (pI) and on the square root of ionic strength in order to reduce the intermolecular repulsion due to the shielding effect of electrolytes (DLVO effect). When Congo red has dianionic form at the pH higher than its pKa, it forms ribbon-like micelle colloids under lower ionic strength, while it loses electrostatic repulsion and aggregates to be emulsified in the octanolic phase under the higher ionic strength. These behaviors of Congo red were resembling to molecular assembly of surfactants. In contrast, the amyloid formation of insulin was proportional to the square root of ionic strength at the pH lower than its isoelectric point. Therefore, the trigger for conformational rearrangement of amyloid fibrillation is predominantly gripped by hydrophobic hydration and an electrostatic shielding effect. We concluded that the both behaviors of Congo red and insulin were derived from a driving force related to the hydrophobic hydration.

Synthesis of a hydrophobic association polymer with an inner salt structure for fracture fluid with ultra-high-salinity water

This study used a compound initiation free radical polymerization process to synthesize a hydrophobic association polymer (PDMA1) with good salt resistance for use in ultra-high salinity reservoirs. The critical association and entanglement concentrations of PDMA1 in deionized (DI) water were 1596 and 2799 mg/L, respectively. The properties of the polymer in simulated formation (SF) water were investigated using viscosity change and conductivity tests, and the apparent viscosity of the PDMA1 solution was investigated using apparent viscosity, viscoelasticity, and thixotropy experiments. To a certain extent, the apparent viscosity of the solution was found to be influenced by metal ions. Under total dissolved solids (TDS) concentrations of up to 239,500 ppm, when the polymer concentration exceeded the critical entanglement concentration, the apparent viscosity of the polymer remained close to that of DI water. Additionally, the viscosity of the PDMA1 solution was affected by different types of metal ions, and the polymer solution thickened owing to divalent cations. PDMA1 is resistant to salt owing to hydrophobic interaction, electrostatic shielding, and double-layer compression. The results of the thixotropy and viscoelasticity tests revealed the thixotropy loop area of the PDMA1 solution in SF water to be greater than that in DI water. Under these conditions, PDMA1 is mostly viscous at low shear frequencies and mostly elastic at high shear frequencies. The PDMA1 inner-salt hydrophobic association polymer can be utilized as a chemical agent for tertiary recovery and fracturing, processes in high-salinity reservoirs, particularly for aggravating fracturing fluid.

Electrochemical Investigation of the Oxidation of Thiosulfate by 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane and Its Anion Radical

AbstractThe oxidation of thiosulfate has been of interest for more than a century, including the famous oscillating iodine clock reaction. From a thermodynamic perspective, calculations based on the reversible potentials reveal that both neutral TCNQF40 (2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane) or its radical anion (TCNQF41−) can oxidize thiosulfate to tetrathionate to form TCNQF42−. The reaction of S2O32− with TCNQF40 in a 2:1 or greater concentration ratio occurs in a step‐wise fashion to initially (and rapidly) form S4O62− and TCNQF41− (reaction 1), followed by a slow step involving the oxidation of residual S2O32− by TCNQF41− to give more S4O62− and TCNQF42− (reaction 2). Thus, this reaction occurs in two, temporally well‐resolved, steps with dramatically different kinetics. If S2O32− and TCNQF41− are mixed in a 1 : 1 ratio, then S4O62− and TCNQF42− are formed quantitatively on the same (hours) timescale, as for the second (slow) step described above. There is no evidence of further oxidation of S4O62− to SO42−. A slight increase in the rate of reaction 2 was observed in the presence of Bu4NPF6 and attributed to ion‐pairing effects. Interestingly, during voltammetric experiments, if the Pt counter electrode is not separated from the reaction solution via a salt bridge, reaction 2 is catalyzed. The rates of reaction 2 have been studied over a wide range of conditions. Intriguingly, the mechanisms are dependent on whether S2O32− or TCNQF41− (much faster) are in excess. With S2O32− in excess, the rate of reaction is first‐order in both S2O32− and TCNQF41−. With TCNQF41− in excess, the reaction is more complicated with indications of Li+ catalysis through electrostatic shielding of the TCNQF41− and/or S2O32− reactants. The large difference in rate of reaction of TCNQF40/S2O32− (rapid) compared with TCNQF41−/S2O32− (sluggish) is in part attributable to the much larger driving force in the former case. All experimental studies were undertaken in the mixed solvent system, acetonitrile (MeCN) containing 5 % water, v/v (95 % MeCN : 5 % water) where all the reactants and products are soluble and stable. Voltammetric analysis using steady‐state (microdisc) or transient cyclic voltammetry (macrodisc) with electrolyte (Bu4NPF6) and UV‐visible spectrophotometry with or without electrolyte were used to monitor the time dependence and establish the identity of the products.

Research on electrostatic shielding characteristics of electrostatic precipitator

Air pollution control is a worldwide problem of common concern to all mankind. Electrostatic precipitator (ESP) plays an important role in the purification of flue gas and dust. At present, in a multi-electrode ESP, the middle discharge electrode is often inhibited by the outer discharge electrode, commonly known as electrostatic shielding, which seriously affects the electric field distribution and dust removal effect of ESP. In order to explore this characteristic, this research established a mathematical model of ESP and simulated the electrostatic shielding phenomenon of wire-plate ESP, which quantified the influence of various factors on the degree of electrostatic shielding and analyzed the potential impact of electrostatic shielding on particle charging and dust removal efficiency. The results of the study show that the wire-to-plate distance has the greatest impact on electrostatic shielding, followed by the discharge electrode radius, voltage, and the wire-to-wire distance. When the degree of electrostatic shielding increases, the dust removal efficiency of ESP decreases. In addition, increasing the number of discharge electrodes to increase the dust removal efficiency of ESP is only feasible within a certain range. When the number of discharge electrodes exceeds a certain threshold, the dust removal efficiency of ESP decreases due to the effect of electrostatic shielding. The results of the research provide guidance for the determination of the geometric parameters of ESP and can make theoretical predictions for the occurrence of electrostatic shielding, thereby effectively avoiding the occurrence of electrostatic shielding. Implications: Electrostatic precipitator plays an important role in the purification of flue gas and dust. Electrostatic shielding seriously affects the electric field distribution and dust removal effect of ESP. The research quantified the influence of various factors on the degree of electrostatic shielding and analyzed the potential impact of electrostatic shielding on particle charging and dust removal efficiency.. It is expected that through the research, some guidance will be provided for the determination of the geometric parameters of ESP and can make theoretical predictions for the occurrence of electrostatic shielding, thereby effectively avoiding the occurrence of electrostatic shielding.

The effect of high-penetrating emission on the growth, superoxide accumulation and ATP/ADP ratio in Saccharomyces cerevisiae

Many kinds of physical fields are able to affect biological activity, such as electromagnetic field, magnetic field, scalar wave, magnetic vector potential and so on. Some works investigated a high-penetrating emission (HPE) generated by a LED generator that can affect the conductivity of water and the growth of dry yeast. In this research, the biological effect of the HPE of LED generator on S. cerevisiae was studied. The results showed that this kind of HPE could promote the growth of S. cerevisiae. With the decrease of initial concentration and the extension of exposure time, the growth promoting effect of HPE increased significantly. When the initial cell concentration was 2 × 102 cell/ml and exposed for 24 h, the number of yeast cells increased by 19.5% compared with the control group. Further studies showed that adenosine triphosphate (ATP) content and the ratio of ATP and adenosine diphosphate (ADP, ATP/ADP ratio) of exposed cells were higher than those of unexposed cells, indicating that exposed cells had higher cell viability and energy status. In addition, the intracellular superoxide (O2−) content decreased significantly after the HPE exposed. In this study, the stainless steel box acts as a Faraday cage to shield the electromagnetic field, so the biological effect of the HPE is not produced by the electromagnetic field. Nevertheless, the mechanism of the HPE is still unknown and needs further research. This is the first report on the effect of HPE on mitochondrial parameters, contributing to further study on HPE and revealing potential for future medical applications.

A review on recent advances in electrodeionization for various environmental applications

The growing contamination of ecosystems necessitates the development of long-term pollution-removal technologies. Electrodeionization, in notably, has newly proven as an efficient method for removing ionic chemicals from polluted waterways. The fact that continuous electrodeionization is a greener technique is most probably the biggest cause for its success. It replaces the toxic chemicals typically required to replenish resins with electric power, therefore eliminating the wastewater involved with resin renewal. In water treatment, electrodeionization solves some of the drawbacks of ion exchange resin beds, particularly ion dumping as beds expire. This comprehensive review explores the theory, principles, and mechanisms of ion movement and separation in an electrodeionization unit. Also, it investigated the construction and usage, notably in removing heavy metal and its current developments in electrodeionization unit. Recent advances in Electrodeionization like polarity reversal, Resin wafer Electrodeionization, membrane free Electrodeionization, and electrostatic shielding with novel materials and hybrid process along with Electrodeionization were addressed. Further advancements are expected in electrodeionization systems that exhibit better efficacy while running at lower costs due to decreased energy usage, rendering them appealing for industrial scale up across a wide range of applications across the world.

A long-standing polarized electric field in TiO2@BaTiO3/CdS nanocomposite for effective photocatalytic hydrogen evolution

Ferroelectrics have the advantage of spatially separating the photogenerated charge carriers via the spontaneous polarized electric field, although the strength of the polarized electric field may suffer from the influence of the electrostatic shielding effect, which could reduce the charge carrier separation without mechanical stress. Herein, we developed a novel CdS decorated TiO2@BaTiO3 core–shell nanocomposite, where the optimal ratio of TiO2, BaTiO3 and CdS are 53.43, 37.37 and 9.20 wt%, respectively, for the best photocatalytic activity. The TiO2@BaTiO3/CdS nanocomposite reported in this work offers a persistent electric field in the ferroelectric BaTiO3 shell, due to the limited shielding effect in an asymmetrically polarized field. With the built-in electric field as the driving force, the photogenerated electrons and holes flowed into the CdS surface and the TiO2 core, respectively, with improved charge separation to participate in water-splitting reactions. The measured charge carrier lifetime of TiO2@BaTiO3/CdS nanocomposite via transient fluorescence spectrum is 0.42 ns, which is much longer than the TiO2 (0.25 ns) and TiO2@BaTiO3 (0.31 ns) samples. The TiO2@BaTiO3/CdS nanocomposite shows an enhanced photocatalytic hydrogen evolution rate of 13.22 mmol/g∙h under visible light illumination with an AQE of 52.50 % at 405 nm monochromatic light. This is much better than their components and binary composites, including TiO2/Pt (0.63 mmol/g∙h), CdS (1.23 mmol/g∙h), TiO2@BaTiO3 (0.03 mmol/g∙h), TiO2/CdS (0.53 mmol/g∙h), and BaTiO3/CdS (2.62 mmol/g∙h). This work provides an effective strategy for the construction of a ferroelectric photocatalyst with much-improved charge separation by the permanent internal electric field.

Formation of a Charged Layer in a Bounded Non-Uniform Magnetized Plasma in RF Field

A model of plasma dynamics in the box of an ICRF (ion cyclotron radio-frequency) antenna without Faraday shield used for the plasma heating in tokamaks is proposed. Formation of a macroscopic layer of oscillating charge that plays a role of a shield is predicted. Relation to phenomena observed in a scrape-off layer plasma is discussed.

Systematic study of cluster radioactivity half-lives based on a modified Gamow-like model

In this study, taking into account of the contribution of the centrifugal potential on half-life and the effect of electrostatic shielding, we modify the Gamow-like model proposed by Zdeb et al [2013 Phys. Rev. C 87, 024 308] to systematically investigate the cluster radioactivity half-lives of nuclei ranging from 221Fr to 238U. The calculated results can reproduce the experimental data well. Additionally, this modified Gamow-like model is applied to predict the half-lives of cluster radioactivity nuclei whose experimental half-lives have the lower limit. It is found that the predicted results are in good agreement with the ones obtained by using the Gamow-like model and a Viola-Seaborg type formula.

Stress-driven surface swell and exfoliation of copper as the plasma-facing materials in NBI ICP source

Neutral beam injection (NBI) heating is a significant auxiliary heating method used in Tokamak fusion devices. The material of faraday shield (FS) and accelerator grids in the NBI inductively coupled plasma (ICP) source can be damaged during operation by the high-density hydrogen plasma irradiation, and thus affecting the stability of the NBI system. In this paper, a series of hydrogen plasma exposure experiments are performed on oxygen-free copper (OFC) specimens at 400 K–850 K with ion energy of 20–200 eV and irradiation fluence up to 1.0 × 1025 m−2. Meanwhile, the rate equation model is adopted for numerical simulation of the bubble growth and hydrogen retention. The influence of OFC surface temperature, hydrogen ion energy and fluence on OFC damage are experimentally and numerically investigated. Surface observations show that swell and exfoliation are formed on the OFC samples at 400 K and 600 K by scanning electron microscopy. The hydrogen ion energy varying from 20 to 200 eV at 400 K is observed to have little effect on OFC surface microstructure. The simulative results show that there exist different critical temperatures when the initial bubble radius changes. The bubble surface density rises and the bubble size decreases with increasing temperature (below the critical temperature). In addition, adjacent bubbles get closer to each other with the growth of hydrogen bubbles, and the strong tensile stress is produced inside the surrounding material of hydrogen bubbles. Some cracks caused by hydrogen bubbles appear on the surface of the OFC to relax the pressure-induced stress, ultimately leading to OFC FS/grids material damage. This investigation helps to understand hydrogen retention and failure mechanisms of OFC materials under extreme operation conditions in the NBI devices.

Inhibition of lithium dendrites and dead lithium by an ionic liquid additive toward safe and stable lithium metal anodes

The uncontrolled growth of lithium dendrites and accumulation of “dead lithium” upon cycling are among the main obstacles that hinder the widespread application of lithium metal anodes. Herein, an ionic liquid (IL) consisting of 1-methyl-1-propylpiperidinium cation (Pp13+) and bis(fluorosulfonyl)imide anion (FSI−), was chosen as the additive in propylene carbonate (PC)-based liquid electrolytes to circumvent the shortcoming of lithium metal anodes. The optimal 1% Pp13FSI acts as the role of electrostatic shielding, lithiophobic effect and participating in the formation of solid electrolyte interface (SEI) layer with enhanced properties. The in-situ optical microscopy records that the addition of IL can effectively inhibit the growth of lithium dendrites and the corrosion of lithium anode. This study delivers an effective modification to optimize electrolytes for stable lithium metal batteries.

STUDY OF THE EFFECT OF MAGNETIC FIELDS ON ELECTROENCEPHALOGRAPHY MEASUREMENT IN FARADAY’S CAGE

Electroencephalography (EEG) is a method for recording the brain's electrical activity through electrodes placed on the scalp's surface. The amplitude of the EEG signal is in the 40–100 V range, with the five main frequencies in the 0 to 100 Hz range. The EEG is non-stationary and very susceptible to various disturbances, especially frequency disturbances, so eliminating troubles in the raw EEG data is essential to obtain helpful information reflecting brain activity. Interference in the EEG signal comes from muscles, eye movement and blinking, power lines, and interference with other devices. The distractions overlap. Shielding is required to perform an EEG without the risk of interference and ambient background noise. This study tested how the influence of magnetic field disturbances on EEG measurements was carried out in the Faraday cage and an unprotected room. The magnetic field was measured before, during, and after the EEG was operated. EEG measurements were performed on subjects who were conditioned to rest for 5 minutes. The EEG signals generated when EEG recordings were performed in the Faraday and the unprotected rooms were compared. It was found that the difference in the value of the magnetic field originating from electronic devices around the subject does not significantly affect the EEG measurement results.

Machine Learning for Automatic Classification of Tomato Ripening Stages Using Electrophysiological Recordings

The physiological processes underlying fruit ripening can lead to different electrical signatures at each ripening stage, making it possible to classify tomato fruit through the analysis of electrical signals. Here, the electrical activity of tomato fruit (Solanum lycopersicum var. cerasiforme) during ripening was investigated as tissue voltage variations, and Machine Learning (ML) techniques were used for the classification of different ripening stages. Tomato fruit was harvested at the mature green stage and placed in a Faraday's cage under laboratory-controlled conditions. Two electrodes per fruit were inserted 1 cm apart from each other. The measures were carried out continuously until the entire fruits reached the light red stage. The time series were analyzed by the following techniques: Fast Fourier Transform (FFT), Wavelet Transform, Power Spectral Density (PSD), and Approximate Entropy. Descriptive analysis from FFT, PSD, and Wavelet Transform were used for PCA (Principal Component Analysis). Finally, ApEn, PCA1, PCA2, and PCA3 were obtained. These features were used in ML analyses for looking for classifiable patterns of the three different ripening stages: mature green, breaker, and light red. The results showed that it is possible to classify the ripening stages using the fruit's electrical activity. It was also observed, using precision, sensitivity, and F1-score techniques, that the breaker stage was the most classifiable among all stages. It was found a more accurate distinction between mature green × breaker than between breaker × light red. The ML techniques used seem to be a novel tool for classifying ripening stages. The features obtained from electrophysiological time series have the potential to be used for supervised training, being able to help in more accurate classification of fruit ripening stages.

Radio properties of the optically identified supernova remnant G107.0+9.0

Context. The vast majority of Galactic supernova remnants (SNRs) were detected by their synchrotron radio emission. Recently, the evolved SNR G107.0+9.0 with a diameter of about 3° or 75 pc up to 100 pc in size was optically detected with an indication of faint associated radio emission. This SNR requires a detailed radio study. Aims. We aim to search for radio emission from SNR G107.0+9.0 by analysing new data from the Effelsberg 100-m and the Urumqi 25-m radio telescopes in addition to available radio surveys. Methods. Radio SNRs outside of the Galactic plane, where confusion is rare, must be very faint if they have not been identified so far. Guided by the Hα emission of G107.0+9.0, we separated its radio emission from the Galactic large-scale emission. Results. Radio emission from SNR G107.0+9.0 is detected between 22 MHz and 4.8 GHz with a steep non-thermal spectrum, which confirms G107.0+9.0 as an SNR. Its surface brightness is among the lowest known for Galactic SNRs. Polarised emission is clearly detected at 1.4 GHz but is fainter at 4.8 GHz. We interpret the polarised emission as being caused by a Faraday screen associated with G107.0+9.0 and its surroundings. Its ordered magnetic field along the line of sight is below 1 μG. At 4.8 GHz, we identified a depolarised filament along the western periphery of G107.0+9.0 with a magnetic field strength along the line of sight B||~ 15 μG, which requires magnetic field compression. Conclusions. G107.0+9.0 adds to the currently small number of known, evolved, large-diameter, low-surface-brightness Galactic SNRs. We have shown that such objects can be successfully extracted from radio-continuum surveys despite the dominating large-scale diffuse Galactic emission.

NOVEL ELECTRIC FIELD EXPOSURE CONTROL METHODS FOR MULTI-STORY BUILDINGS INSTALLED IN VICINITY OF HIGH-VOLTAGE APPARATUS USING FEM

Facilities and buildings installed nearby high voltage equipment and electric field exposure is always a serious threat to the health of organisms and can have a significant impact on the functioning of sensitive and vital organs such as the heart and brain. Therefore, it is necessary to study the electromagnetic field value in these areas to control the intensity and restrict the induced value regarding to international recommendations. In this paper, the effects of 230KV transmission line electric fields on the environment are examined by proper FEM software.The model under consideration in this project is a four story building adjacent to the 230KV transmission line.At first, the distance between the building and high voltage transmission lines and its relationship to the intensity of the electric field is examined, and then the intensity of the electric field is compared to the standards of the International Commission on Non Ionizing Radiation Protection (ICNIRP). To continue, in places where the electric field exceeds the standard level value, solutions to reduce the intensity of the electric field to the tolerable value have been proposed.The first solution is to use a metal shield around the building as a Faraday cage, which weakens the potential for electric field value by creating an enclosed surface, the reduction rate is 4700%,both complete cage shape and incomplete cage shapes are considered in this study which reduces the exposure value to 62.5% of its initial value. The second approach to reducing the electric field is to use protective conductor paints against electromagnetic fields. In the following study, the effect of using trees as a barrier against electromagnetic radiation will be examined. Finally, the three proposed solutions are compared in terms of environmental constraints, economic justification, and the reduction in electric field value.

Destruction of hydrogen bonding and electrostatic interaction in soy hull polysaccharide: Effect on emulsion stability

Hydrogen bonding and electrostatic interactions play an important role in the microstructure of soy hull polysaccharide (SHPA) and the stability of corresponding emulsions. In this study, urea and NaCl were added in the preparation of samples, which could destroy these two noncovalent interactions, and they were labeled as SHPA-U and SHPA-N, respectively. The results show that more hydrogen bonding was generated along with the electrostatic shielding effect, which led to longer and branched polysaccharide chains of SHPA-N. However, the chain of SHPA-U was rough and fragmentary, which may be attributed to hydrogen bonding and protein regions destroyed by urea. Furthermore, the addition of NaCl and urea led to lower interfacial pressure, and the adsorption kinetics at the oil/water interface were significantly changed. In addition, all emulsions had a liquid-like structure, and both SHPA-N and SHPA-U emulsions had a bimodal size distribution. The relaxation time and line width of the 1H NMR analysis decreased with the addition of NaCl and urea, indicating the decreasing interaction between SHPA-N/SHPA-U and oil molecules. These phenomena were related to the coalescence and flocculation in these two emulsions. After 24 h of storage, the stability of the SHPA-N emulsion was superior to the others; this may be due to its higher viscosity. This study laid the foundation for further research on the mechanism of polysaccharide O/W emulsions stabilized by SHPA and other polysaccharides.

Sub-Nanometer Confined Ions and Solvent Molecules Intercalation Capacitance in Microslits of 2D Materials.

The ion intercalation behavior in 2D materials is widely applied in energy storage, electrocatalysis, and desalination. However, the detailed effect of ions on the performance, combining the influence of interlayer force and the change of solvent shell, is far less well understood. Here the solvated alkali metal ions with different sizes are intercalated into the lattice of 2D materials with different spacings (Ti3 C2 Tx , δ-MnO2 , and reduced graphene oxide) to construct the intercalation model related with sub-nanometer confined ions and solvent molecules to further understand the intercalation capacitance. Based on electrochemical methods and density functional theory calculation, the ions lose the electrostatic shielding solvent shell or shorten the distance between the layers, resulting in a significant increase in capacitance. It is found that the intercalation capacitance arises from the diffusion of solvated ions and is controlled by quantum and electrochemical capacitance for desolvated ions. This effect of solvation structure on performance can be applied in a variety of electrochemical interface studies and provides a new research view for energy storage mechanisms.

Electroanalytical Measurements of Lanthanum (III) Chloride in Molten Calcium Chloride and Molten Eutectic Calcium Chloride and Lithium Chloride

Cyclic voltammetry (CV), square wave voltammetry (SWV) and other electroanalytical methods have been applied to molten chloride salts to study metal ion behavior. These studies have been useful for understanding and optimizing the electrorefining and electrowinning of metals. Notable ions that have been studied are rare earth (RE) and actinide metals in eutectic KCl-LiCl salts. However, the behavior of lanthanum (La3+) ions (a RE metal commonly used as a glass additive, component in electric motor vehicle batteries, etc.) in some molten chlorides or chloride mixtures, such as CaCl2, has not been studied. To facilitate the study of La3+ ion behavior, electroanalytical measurements in molten salts require improved experimental techniques to perform appropriate measurements. CV experiments were conducted to evaluate La3+ behavior in eutectic LiCl-CaCl2 and CaCl2 and are compared to La3+ behavior in LiCl-KCl and CaCl2-NaCl eutectics from other studies. The electrochemical reaction was checked for reversible, quasi-reversible, and irreversible transitions in scan rate by examining the relationship between the scan rate applied and the peak current and potential for La3+ reduction. Properties such as diffusion coefficient (Do) and electrons exchanged (n) are calculated from data demonstrating reversible or irreversible behavior. The electrochemical setup was also checked for radial diffusion via error measurements for semi-infinite linear diffusion, which led to the observation that natural convection possibly effected the La3+ reduction peak at low scan rates. For more accurate electroanalytical measurements of La3+ reduction, CVs with and without LaCl3 added to CaCl2 and eutectic CaCl2-LiCl were compared to establish baselines for the La3+ reduction peak. The impact of resistance (IR) compensation on the La3+ reduction peak is also explored. Techniques and practices that optimized electroanalytical performance include placing the electrolytic cell in a Faraday cage, distancing electrodes from the heating coils, and melting the chlorides twice prior to measurements.

Effect of High Dielectric SrF2 in TiO2 photoanode for Dye-Sensitized Solar Cell Applications

Dye-sensitized solar cells (DSSC) have been extensively investigated as promising candidate for solar energy conversion owing to their low cost, eco-friendly and high device efficiency. Among the other, photoanode is one of the key components in DSSC which defines its performance. Charge recombination and low light harvesting are the two major drawbacks of conventional TiO2 photoanode which limits the device efficiency. With this aim, the present work focused on the preparation of high dielectric SrF2 nanoparticles (ε’=6.844 x 106 at 1 Hz) and its study on incorporation with TiO2 photoanode with various weight percentages for device assembly. It can reduce the recombination by strong electrostatic shielding and increase the charge collection efficiency through interfacial polarization at dielectric-semiconductor interface shown in Fig.1. Improved power conversion efficiency (PCE) of 7.581% is obtained in 10 wt% SrF2:90 wt% TiO2 based photoanode which is 8.3% higher than the device efficiency of pure TiO2 based DSSC (6.997%). The interfacial charge transport kinetics of fabricated DSSCs are also explored using electrochemical impedance spectral (EIS) analysis. Low recombination resistance Rrec (49.9 Ω) in 10 wt% SrF2:90 wt% TiO2 based DSSC reveals the reduced recombination dynamics compared to other devices due to the optimized concentration of SrF2 incorporation in TiO2 photoanode for balancing charge injection and recombination. Keywords: DSSC; SrF2; Interfacial polarization; Dielectric constant and EIS Acknowledgement: This work was supported by Brain Pool Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, Korea. (Grant number: 2019H1D3A1A01071183). It was also supported by the Technology Development Program to Solve Climate Changes of the National Research Foundation, funded by the Ministry of Science, ICT & Future Planning (No: NRF-2016M1A2A2940912). Fi gure.1. Dielectric plot as a function of angular frequency (Inset shows interfacial polarization at dielectric-semiconductor interface). Figure 1

Slanted nanostructures capped with SiO2 nanospheres for asymmetric hydrophilicity inducing rapid unidirectional water spreading

Two levels of nanostructures, consisting of slanted nanostructure and nanogroove, were fabricated on polymeric surface through a single step oxygen plasma processing with tuning incident angles. A polymeric sheet embedded with the SiO2 nanospheres was exposed to the oxygen plasma through Faraday cages to induce anisotropic etching. The nanopillars were slanted by changing the relative angle between plasma ions and polymer substrate from 10 to 80°. The nanogrooves were also formed among the slanted nanopillars along the trajectory of plasma ions. Together with the nanogrooves, the slanted nanopillars enhanced unidirectional water spreading. The wetting behaviors, with gradual transformation through four stages with different degree of hydrophilicity (super-, strong, moderate, and mild hydrophilicity), were observed. The surface with moderate hydrophilicity showed strong asymmetric wetting for unidirectional water spreading, against the gravity force, at very high velocity (up to 1.5 ∼ 4.17 mm/sec). This easy and simple fabrication method of slanted nanostructures could be utilized in a wide range of applications requiring long-lasting hydrophilicity with asymmetric wetting, such as, microfluidic, oil–water separation, water-harvesting, and biomedicines.