Changes In Electrical Conductivity Research Articles

Ionic liquids with reversible photo-induced conductivity regulation in aqueous solution

Stimulus-responsive ionic liquids have gained significant attention for their applications in various areas. Herein, three kinds of azobenzimidazole ionic liquids with reversible photo-induced conductivity regulation were designed and synthesized. The change of electrical conductivity under UV/visible light irradiation in aqueous solution was studied, and the effect of chemical structure and concentration of ionic liquids containing azobenzene to the regulation of photoresponse conductivity were discussed. The results showed that exposing the ionic liquid aqueous solution to ultraviolet light significantly increased its conductivity. Ionic liquids with longer alkyl chains exhibited an even greater increase in conductivity, up to 75.5%. Then under the irradiation of visible light, the electrical conductivity of the solution returned to its initial value. Further exploration of the mechanism of the reversible photo-induced conductivity regulation of azobenzene ionic liquids aqueous solution indicated that this may attributed to the formation/dissociation of ionic liquids aggregates in aqueous solution induced by the isomerization of azobenzene under UV/visible light irradiation and resulted the reversible conductivity regulation. This work provides a way for the molecular designing and performance regulation of photo-responsive ionic liquid and were expected to be applied in devices with photoconductive switching and micro photocontrol properties.

Thermoresistivity of Carbon Nanostructures and their Polymeric Nanocomposites

AbstractCarbon nanostructures such as carbon nanotubes, graphene, and its multi‐layer derivatives exhiibit temperature‐dependent electrical conductivity. They can form percolated networks inside polymers, which render electrical conductivity to nanocomposites. Upon the formation of a percolated network, thermal energy applied to the material drives structural changes of the network, which manifest as changes in electrical conductivity. This principle is used to develop smart materials with self‐sensing temperature capabilities. This critical review covers past and present research on the electrical response to temperature (thermoresistivity) of carbon nanostructures and their polymeric nanocomposites. It covers few‐ and multi‐layer graphene, carbon nanotubes, carbon‐nanostructured arrays and fibers (yarns). The mechanisms driving the thermoresistive response of individual nanostructures, their arrays, and of their polymeric nanocomposites are addressed. The role of the nanostructured filler on the thermoresistivity of polymer nanocomposites depends on its morphology and concentration. For low filler concentrations, thermal expansion of the polymer may dominate over the inherent thermoresistivity of the filler. For high filler concentrations, or for densely packed arrays of carbon nanostructures, the inherent (quantum) thermoresistive response of the nanostructures becomes dominant. The review addresses recent progress in the field, highlights current issues, synthesizes published data, and provides outlooks and insights into future directions.

Commercial scale production of Yamabushitake mushroom (Hericium erinaceus (Bull.) Pers. 1797) using rubber and bamboo sawdust substrates in tropical regions

Yamabushitake (Hericium erinaceus) is one of the most sought out mushrooms that is widely used for both direct consumption and medicinal purposes. While its demand increases worldwide, cultivation of the mushroom is limited to temperate areas and its production in tropical regions has never been explored. The aim of this study was to test the utilization of rubber and bamboo sawdust, alone or as a substrate mixture, for industrial scale Yamabushitake mushroom production. Five substrate treatments with various ratios of the two sawdust were compared for their physicochemical properties in relation to mushroom productivity. The highest mushroom fresh and dry (113.22 and 23.25 g, respectively), biological efficiency (42.61%), and cap size (9.53 cm) were obtained from the substrates containing 100% rubber sawdust, with the mushroom yield decreasing proportional to the ratio of bamboo sawdust. The 100% rubber sawdust substrate provided a higher initial organic matter and carbon content together with C:N ratio at 63.2%, 36.7% and 65.48, respectively, whereas the 100% bamboo sawdust provided higher nitrogen content (1.03%), which was associated with lower mushroom yield but higher number of fruiting bodies. As in the 100% rubber sawdust substrate, a comparable mushroom yield and growth attributes were also obtained in the 3:1 rubber-bamboo sawdust mixture substrate. Principle component analysis of the measured variables indicated a strong influence of substrate C:N ratio before spawning and the change in substrate electrical conductivity and N content after cultivation to the variation in mushroom productivity among the treatments. The results demonstrate the applicability of rubber sawdust and its combination with up to 25% of bamboo sawdust for Yamabushitake mushroom cultivation and provide the basis for substrate optimization in the tropical Yamabushitake mushroom industry through a circular economy framework.

A new trinuclear Cd(II)-based coordination polymer with Salen ligand building blocks: Synthesis, crystallographic aspects, and optimistic photosensitive Schottky barrier diode behaviour

A new X-ray-characterized Cd(II)-based coordination polymer has been synthesized using Salen ligand (H2L1) and dicyanamide ion (dca) [N(CN)2]−, and characterized using elemental analysis, spectroscopy, SEM/EDX, TEM, and powder X-ray diffraction techniques. According to SCXRD, the complex crystallizes in the triclinic space group P-1. The asymmetric unit includes de-protonated ligands [L]2−, Cd(II) centres, and dca ions. The complex binuclear parts are connected by two μ1,5-dca bridges, resulting in the creation of a one-dimensional coordination polymer [(L1Cd)2(μ1,5-dca)2Cd]n. The polymer undergoes supramolecular aggregation via hydrogen bonding, CH···π(dca), and CH···π(arene) interactions. Hirshfeld surfaces (HS) and 2D fingerprint plots have been deployed to visualize the supramolecular interactions. The analysis shows that N…H interactions (18.2%) are more common in the crystal packing than Cd···O/O···H. This complex displays electrical conductivity and photosensitivity properties, making it a promising material for optoelectronic applications. Experimental and DFT studies have confirmed that it is a direct semiconductor with a specific optical band gap (3.54 eV) and is also used to construct a photosensitive Schottky barrier diode (SBD). The DFT calculated optical conductivity was used to analyse how the material's conductivity changes upon illumination. Due to the photon absorption, the material's electrical conductivity and photoconductivity change were concomitantly observed. Finally, the DOS analysis explains the complex's conductivity behaviour in a better logistic way.

Microstructure correlated optical, electrical, mechanical properties and photodegradation activities of mechanically alloyed nanocrystalline Bi1.5Sb0.5Te3 as a thermoelectric material and efficient photocatalyst

Phase pure and 25 % Sb incorporated Bi2Te3 compounds with a rhombohedral crystal structure are synthesized by mechanical alloying the stoichiometric mixtures of elemental powders within 3 h under an inert atmosphere. The structure and microstructure of the synthesized samples are revealed by analyzing XRD patterns with Rietveld refinement, FESEM, HRTEM images, and EDX spectra. The increment of lattice parameter ‘c’ with increasing milling time is associated with the increased [Bi/SbTe] type antisite defects. Optical bandgaps of the pure and Sb-alloyed Bi2Te3 samples of different sizes are determined from the FTIR spectra. The transition of undoped n-type to Sb-alloyed p-type semiconducting nature is revealed from the photo responses of the samples. The ac electrical conductivity as well as complex impedance spectra in the temperature range 303–403 K reveal the semi-metallic, non-Debye type behavior of the samples and temperature-dependent relaxation phenomena. The change in electrical conductivity and the corresponding activation energies due to Sb alloying and for different grain sizes are explained in terms of antisite defects and porosity of materials. The temperature variation of the frequency exponent has been demonstrated with the small polaron hopping transaction. The Mott VRH model is used to explain the electrical conduction mechanism of the synthesized samples. The variation of Vickers microhardness with the grain size of milled samples corroborates well with the Hall-Petch relation. The normal indentation size effect (ISE) is depicted from Meyer's law. The photocatalytic activity of 10 h milled Sb-alloyed sample to degrade Rhodamine B cationic dye in wastewater is ∼ 91 %. The correlations of electrical and mechanical properties with the photocatalytic activity of the samples have been established.

Effect of annealing treatment on microstructure of micro arc oxidation ceramic film on Al-Mg-Sc alloy

The effect of annealing treatment on the microstructure of micro arc oxidation (MAO) ceramic film prepared on Al-Mg-Sc alloy was studied. Results suggested that the difference of microstructure of Al-Mg-Sc alloy after various ageing treatment mainly focused on the evolution of dislocation density and the precipitation of β phase (Al3Mg2), and this difference induced the component transformation of surface oxide film from Al2O3 and MgO to MgO and MgAl2O4.Meanwhile, when the other parameters were kept constant, the relevant relations between the microstructure evolution and precipitation phase and the substrate induced the changes of electrical conductivity, then determining the characteristics of MAO ceramic film. Without sacrificing any strength, the optimal MAO ceramic film owning the higher thickness and lower porosity was obtained on Al-Mg-Sc alloy after annealing treatment at room temperature, and tightly bonded to the substrate, which provided a theoretical basis for subsequent research to improve the corrosion resistance of Al-Mg-Sc alloy.

Determining Homogenization Parameters and Predicting 5182-Sc-Zr Alloy Properties by Artificial Neural Networks.

Artificial neural networks (ANNs) were established for the homogenization and recrystallization heat treatment processes of 5182-Sc-Zr alloy. Microhardness and conductivity testing were utilized to determine the precipitation state of Al3(ScxZr1-x) dispersoids during the homogenization treatment, while electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) were used to observe the microstructure evolution of the alloy. Tensile experiments were performed to test the mechanical properties of the alloy after recrystallization annealing. The two-stage homogenization parameters were determined by studying the changes in microhardness and electrical conductivity of 5182-Sc-Zr alloy after homogenization with the assistance of artificial neural networks: the first-stage homogenization at 275 °C for 20 h and the second-stage homogenization at 440 °C for 12 h. The dispersoids had entirely precipitated after homogenization, and the alloy segregation had improved. A high-accuracy prediction model, incorporating multiple influencing factors through artificial neural networks, was successfully established to predict the mechanical properties of the 5182-Sc-Zr alloy after annealing. Based on the atomic plane spacing in HRTEM, it was determined that the Al3(ScxZr1-x) dispersoids and the Al matrix maintained a good coherence relationship after annealing at 400 °C.

Metal-organic frameworks-derived MCo2O4 (M = Zn, Ni, Cu) two-dimensional nanosheets as anodes materials to boost lithium storage

Transition metal oxides (TMOs) have received significant consideration. Because of their enormous theoretical capacity, cheap, and less toxicity. Notably, cobalt-based materials hold promises as negative electrode materials for batteries, but they suffer from less electrical conductivity and significant volume changes during operation. In order to address these challenges, sacrificial templating techniques at the nanoscale offer a potential solution for improving the electrochemical stability and rate performance of these materials. More specifically, these tactics have proven popular for designing Li-ion storages. To ascertain the impact of multiple metal ions on the electrochemical capacity, metal organic frameworks (MOFs) derived MCo2O4-MOF (M = Zn, Ni, Cu) were developed. Among these, ZnCo2O4 showed the best electrochemical performance (927.2 mAh g-1 at 0.1 A g-1 after 250 cycles). Furthermore, calculations based on density functional theory (DFT) revealed that ZnCo2O4 had the lowest Li+ adsorption energy, with a minimum value of −1.61 eV. Moreover, this research aims to design controllable nanostructures in order to enhance the design of transition bimetallic oxide composites for energy storage applications.

Impact of Silicon Content and Particle Size in Lithium-Ion Battery Anodes on Particulate Properties and Electrochemical Performance

Silicon (Si) is considered a promising anode active material to enhance energy density of lithium-ion batteries. Many studies have focused on new structures and the electrochemical performance, but only a few investigated the particulate properties in detail. Therefore, a comprehensive study on the impact of Si content (5, 10, 15 wt.%) and particle size (120, 160, 250 nm) of core–shell structured Si@Gr composites on particulate and electrode properties was conducted. It was shown that both parameters had significant impact on the specific surface area (SSA) of particles, which was later correlated to the initial capacities and coulombic efficiencies (ICEs). Furthermore, changes in pore size distribution and electrical conductivity were found. The built full cells showed high initial capacities (>150 mAh g−1), good rate capability (75% at 1 C, 50% at 2 C) and ICEs (>80%). The energy density was found to increase by 32% at 15 wt.% Si compared to graphite (Gr), indicating the future potential of Si. In addition, the impact of a carbon coating was investigated (Si@Gr/C), which led to a reduction in SSA, improved particle stability and higher capacity retention. Consequently, this study emphasizes the importance of also investigating the particulate properties of Si anodes.

Enhancing the thermal stability of S/Se based thermoelectric materials using self-generated oxide films

This study focuses on the thermal stability of Cu1.8S materials. During the ball milling process, metal powder is added to the milled Cu1.8S powder, and then the obtained powder is sintered using current assisted sintering to obtain dense blocks. The aim is to enable the added metal elements to spontaneously grow an oxide film on the surface of the material block at high temperature, achieving protection of the material matrix. The thermal stability of materials is evaluated by utilizing changes in room temperature phase composition before and after high-temperature heat treatment, changes in material electrical conductivity during high-temperature processes, and cyclic electrical transmission performance testing. By observing the surface oxide film state of the material after high-temperature treatment, the commonalities and differences in the effects of different element additions on the thermal stability of the material were analyzed. The effects of different metal elements on material hardness and electrical transmission performance were evaluated. It is found that adding metal powder can effectively improve the thermal stability of Cu1.8S, improve material hardness, and regulate the electrical transmission performance of the material. The characteristics of the oxide film formed by the spontaneous growth of metal elements and oxygen on the surface of the material substrate determine the effectiveness of the oxide film in protecting the material from high temperatures. The pure Cu1.8S bulk can only maintain stability at 300 oC, and the addition of Cr, Al, 316L, Fe, and Mn powder respectively increased the stable temperature of the material to 400, 400, 450, 450, 500 oC. Adding metal elements to the material matrix to grow an oxide film on the surface of the material to prevent high-temperature oxidation or decomposition is an effective way to improve the thermal stability of S/Se compounds.

The application of a wavelet filtering method in magneto-acousto-electrical tomography

Magneto-acousto-electrical tomography (MAET), which couples ultrasound imaging with electrical impedance tomography, is an electrical property imaging method which is expected to have a wide range of clinical applications, including the early detection of breast and liver cancers. Obviously, as a coupled imaging method, how to improve the signal-to-noise ratio (SNR) is a key issue in the imaging process. In this paper, a wavelet filtering method is introduced into MAET, which includes the filtering effect of the db6 wavelet, and its filtering effect at different decomposition levels. At the same time, based on the Lorentz reciprocity theorem, the wave equation satisfied by the detected voltage obtained by electrode was deduced. We also built an experimental platform to acquire signals by keeping the position of the target unchanged and moving the ultrasound transducer along the trajectory of a circular arc. The experimental results show that the wavelet filtering scheme proposed in this paper improves the SNR of the detected signal of 15.1 dB, and the images of electrical properties of the phantom and pork from isolated tissues were realized by the filtered signal of the db6 wavelet and time reversal method, which reflects the interface of electrical conductivity change of tissues. This scanning method, of fixing the target body and rotating the transducer, can effectively reduce the error and noise caused by the movement of the detection electrodes in the experiment. The filtering technique and imaging algorithm proposed in this paper have improved the SNR and contrast of the images. Thus, the images of the low conductivity phantom with 0.2 S m−1 and isolated tissue were obtained, which indicates that the MAET has good prospects in clinical applications.

Anti-Fusarium activity of essential oil distilled from artemisinin (Artemisia annua L.) extraction residues

Fusarium, a major phytopathogen damages field crops causing huge losses to agriculture. This study evaluated the anti-Fusarium effects of essential oil distilled from artemisinin extraction residues (EOAR). The chemical composition of EOAR was analyzed and its growth inhibition effect was examined against four Fusarium species. The underlying molecular mechanism was uncovered by studying the changes in growth rate, mycelial morphology, biomolecular leakage, electrical conductivity, and transcriptome of the fungi. The results indicated that the main components of EOAR (such as camphor, borneol, etc.) significantly inhibited the growth of Fusarium by destroying the morphology and structure of cytomembrane, and promoting the leakage of intracellular biomolecules. Transcriptome analysis showed that the differentially expressed genes after treatment with EOAR were mainly related to the transmembrane transport pathway and activity, carbon metabolism, and ribosome function of F. graminearum. Our findings suggest that oily waste from Artemisia annua after extraction of artemisinin can be recycled for the production of EOAR, which can be a potential green and effective fungicide against Fusarium.

Electrical conductivity and species distribution of aluminum chloride and 1‐butyl‐3‐methylimidazolium chloride ionic liquid electrolytes

AbstractElectrical conductivity (σ) of aluminum chloride (AlCl3) and 1‐butyl‐3‐methylimidazolium chloride (BMIC) ionic liquid (IL) was investigated as a function of temperature and AlCl3 mole fraction ( ). Electrochemical impedance spectroscopy was used to measure the electrical conductivity. Composition of AlCl3:BMIC ionic liquid was varied by changing the from 0 to 0.67. The temperature was changed from 70°C to 110°C at 10°C intervals. It was found that the electrical conductivity increases with an increase in temperature. Electrical conductivity increases with from 0 to 0.5 and then starts to decrease after = 0.5. A species concentration profile was developed based on thermodynamic model at room temperature for the IL containing , , , , , , and at different . The only anion species presents between 0 and 0.5 are and . Anions like , , , and are found at higher . A good agreement between the model and the experimental data was obtained. The variations in anion concentration, molecular structure, and cation–anion interactions are to be the causes of the changes in electrical conductivity of AlCl3:BMIC system.

Cell leakage mechanism and time kill studies on Staphylococcus aureus after exposure to ethanol leaf extract of Muntingia calabura L

Purpose: To determine the effect of the ethanol leaf extract of M. calabura (EEMC) on cell leakage and time-kill against S. aureus. 
 Methods: The leaves were macerated with 96 % ethanol (1:8; w/v) for 27 h to produce EEMC. Chemical compounds of EEMC were analyzed using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Various concentrations of EEMC (12.5; 25; 50; 100 mg/mL) were tested to determine the Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against S. aureus. Furthermore, EEMC was tested for its effect on cell leakage, changes in extracellular electrical conductivity, and time-kill against S. aureus. UV-spectrophotometer was used to test for leakages of nucleic acid, protein, DNA, and RNA, while atomic absorption spectrophotometer was used to evaluate leakage of potassium ion (K+).
 Results: The MIC and MBC of EEMC against S. aureus were 10 % w/v (100 mg/mL). The highest cell leakage occurred in S. aureus exposed to 2x MIC, with leakages of protein, DNA, RNA, and K+ reaching 137.79 ± 58.99, 2298 ± 263.26, 1839 ± 210.61 and 770.86 ± 40.11 μg/mL respectively. The EEMC (1x MBC and 1.5x MBC) killed S. aureus in 24 h. Analysis of LC-MS/MS of EEMC showed that flavonoids (48.33 %) followed by anthraquinones (16.10 %) were the major classes of compounds present in the extract.
 Conclusion: The ethanol leaf extract of M. calabura kills S. aureus by inducing cell leakage possibly due to flavonoids and anthraquinones contained in it. The extract should be further isolated and its active principles with potent antibacterial properties developed for therapeutic applications.

Development of a Monitoring System for Huangjiu Storage based on Electrical Conductivity

Abstract In this study, a fast rancidification detection method was developed for Huangjiu in pottery jars based on the principle of electrical conductivity changes caused by microbial contamination. The change of total acid in Huangjiu was positively correlated with the increase of electrical conductivity. This method was applied to an online monitoring system for Huangjiu storage in stainless steel tanks. When the electrical conductivity exceeds the normal fluctuation range (Mean + 3 standard deviations) of previous data, the monitoring system recognizes the microbial contamination. By optimizing the conductivity-temperature compensation coefficient and conductivity statistical method, the standard deviation of the method was reduced and the sensitivity of microbial pollution monitoring was improved. The ranges of conductivity and compensation coefficient of common types of Huangjiu were estimated. Interference in conductivity measurements due to environmental factors was minimised through the synchronous comparison of conductivity data for multiple tanks of Huangjiu. The standard deviation (SD), which indicates the fluctuation range of the system, decreased from 143 μS/cm to 2 μS/cm. The monitoring system was then applied in Huangjiu storage tanks with capacities of 60 t and 300 t. Through the comparison of conductivity data change, the abnormal signals caused by microbial contamination during the storage of Huangjiu were found in time. Meanwhile, through off-line detection of total acid of Huangjiu, the effectiveness of microbial contamination on-line detection was verified.

Quenching-induced construction of graphene-wrapped Fe3O4 composite as ultrahigh-performance Li-storage electrode

Iron oxide/graphene hybrids are outstanding electrodes with high specific capacity for secondary batteries. However, in practice there still remains challenges in alleviating the poor electrical conductivity and significant volume changes of FeOx during the lithiation/delithiation process. Herein, we describe the discovery of fabricating graphene-wrapped Fe3O4 (3D-rGO/Fe3O4) via a solution-based self-assembly process. During which, GO/Fe3O4/Na2SO4 precursor was first formed by the corrosion reaction of metallic Fe in GO aqueous solution and antisolvent self-assembly, which was then quenched into water to dissolve the Na2SO4 template and meanwhile enable the GO to shrink and encapsulate the Fe3O4 nanoparticles spontaneously, followed by a final thermal reduction. Fe3O4 nanoparticles, with a diameter of tens of nanometers, are homogeneously enwrapped into rGO framework, guaranteeing the “plane-to-plane” interconnection. The obtained 3D-rGO/Fe3O4 demonstrates unprecedented Li-storage behaviors when utilized as Li-ion battery anode. Furthermore, quantitative kinetic analysis revealed that both capacitance and diffusion mechanisms account for Li-storage behavior. This contribution not only presents a ultrahigh-performance Li-storage electrode but also shows a novel methodology to design and construct other graghene-based metallic compounds for various applications.

Titanium (IV) oxide composite hollow nanofibres with silver oxide outgrowth by combined sol–gel and electrospinning techniques and their potential applications in energy and environment

A two-dimensional nanostructure composed of Ag2O nanobranches attached to TiO2 hollow nanofibres (denoted as 2D Ag2O/TiO2) was successfully prepared via sol–gel and coaxial electrospinning techniques. The Ag/TiO2 hollow nanofibres were fabricated and calcined in ambient air at 500 °C. By calcination, the removal of organic materials and the formation of anatase TiO2 were achieved with a well-retained hollow structure. The embedded Ag nanoparticles functioned as seeds for the Ag2O outgrowth on the TiO2 surface using a hydrothermal treatment at different times and temperatures, which caused the change in physical appearance, surface area, and electrical conductivity of 2D Ag2O/TiO2. A high quantity of Ag2O nanobranches on TiO2 nanofibres were obtained with increasing the temperature from 110 to 115 °C and the reaction time to 60 min. Consequently, the electrochemical active surface area (EASA) value was maximised to 65.25 cm2 per cm2 with an enhanced electrical conductivity of 91.3 ± 3.9 × 10−2 S cm−1. Further studies on the depth-profiles of Ag, Ti, and O revealed the presence of Ag2O attached to the core structure of TiO2. The photoelectrochemical and photocatalytic tests confirmed the excellent physical and electrochemical properties of 2D Ag2O/TiO2 (@115 °C, 60 min) for use in energy and environmental applications.Graphical

Synthesis, Characterization and Impedance Analysis of CalciumDoped Zinc Oxide Nanoparticles

The calcium-doped ZnO nanoparticles, Zn1-xCaxO (x = 0, 0.025, 0.05, 0.075) were prepared by the solution combustion method. The synthesized nanoparticles were characterized by various techniques such as XRD, FTIR, Raman, FESEM-EDX, PL, Impedance, and UV-Vis. The Rietveld refinement of the X-ray diffractogram yields the crystalline structure and lattice parameters. Also, the XRD analysis shows that the substitution of Ca into ZnO does not alter the Wurtzite structure of ZnO. The crystallite size of the samples, calculated using the Scherer equation, was found to be between 46 nm and 92 nm. FTIR spectra detect the ZnO-related vibration modes of the samples. The FESEM morphological images suggest the spherical shape of the synthesized nanoparticles. The EDAX spectra identify the presence of Zn, Ca, and O atoms in the samples. The Raman active modes of the ZnO phase were identified by Raman spectral analysis. The analysis of Photoluminescence (PL) spectra gives information about the UV emission and other visible bands corresponding to violet, blue, and green emission representing different intrinsic defects in synthesized nanoparticles. Using UV-vis spectroscopy, the optical transparency and band gap values were examined. The energy band gap obtained by Tauc’s plot was decreased with the increase in Ca doping. Impedance analysis shows that the grain conductivity increased with the increase in dopant concentration. Contrarily, the total conductivity decreased with the increasing doping concentration due to increased grain boundary resistance. The proposed work demonstrates the changes in microstructure, electrical conductivity, and optical bandgap energy with Ca-doping. These synthesized Ca-doped ZnO nanoparticles could be promising materials for photocatalytic applications.

Field-induced chiral transitions in the Weyl semimetal TaP

The chiral anomaly effect has been regarded as a hallmark of Weyl semimetals. While most research focuses on the change of electrical conductivity due to the chiral charge-pumping effect, these transport measurements are accompanied by other effects such as weak antilocalization which are difficult to exclude. Also, the magnetic field intensity at which the energy dispersion of the Landau level starts to display the chiral anomaly effect is hard to identify. Here, we report the evolutionary process of the energy dispersion of the zeroth Landau level under increasing magnetic fields, and we elucidate the relationship between the chiral Landau level and the Fermi level via magneto-optical measurements in Weyl semimetal TaP. Two series of Landau-level transitions have been extracted and fitted well to a massless Weyl fermion model and a classical semiconductor model, respectively. The field-induced chiral Landau-level transition is obtained from a comparison between the spectra under Voigt geometry and Faraday geometry in an increasing magnetic field. The chiral nature of the zeroth Landau level is found to enhance with the increase of magnetic field and clearly manifests in the magneto-optical spectrum above 13 T. The state transition of the zeroth Landau level can be explained by the strength of the field-induced chiral anomaly effect and the position of the Fermi level. These magneto-optical results unveil the chiral Landau-level transitions in TaP, which serves as an ideal material platform to analyze the chiral anomaly effect.

A Technique for Multi-Parameter Signal Processing of an Eddy-Current Probe for Measuring the Thickness of Non-Conductive Coatings on Non-Magnetic Electrically Conductive Base Metals

The known amplitude-sensitive eddy-current method for measuring the thickness of non-conductive coatings on conductive non-magnetic base metals does not satisfy the accuracy requirements. A primary consideration is the significant influence of a change in the specific electrical conductivity of the base metals on results of measurements. In this study, we developed a technique for measuring the thickness of non-conductive coatings on non-magnetic conductive base metals by using the eddy-current amplitude-phase method and implemented algorithms to process obtained information. Our method considered the influence of the specific electrical conductivity of the base metals by forming a two-dimensional graduation characteristic of the thickness gauge by using several base metals with different specific electrical conductivity. The algorithm for point-in-polygon determination was applied, which allowed us to measure the thickness of the coatings and the specific electrical conductivity of the base metals as independent values. The equipment necessary to construct the two-dimensional graduation characteristic and the algorithm for calculation of the thickness are described in detail.