Electrons In Metals Research Articles

284 Impact of Novel Reconstruction and Metal Artifact Reduction Algorithms on Metal Electron Density Curve for KVCT Simulator

284 Impact of Novel Reconstruction and Metal Artifact Reduction Algorithms on Metal Electron Density Curve for KVCT Simulator

The Influence of a Non-Physical Work Environment, Transformational Leadership, and Work Motivation as Mediating Variables on the Performance of State Civil Apparatus in the Directorate General of Metal Industry, Machinery, Transportation and Electronics

This study aims to analyze the effect of non-physical work environments, transformational leadership, and work motivation on the performance of ASN Ditjen ILMATE. The population is all ASN employees in the ASN Directorate General of ILMATE, totaling 230 employees with a sample of 147 employees. Data analysis using the SEM-PLS technique The results of the study found evidence that, partially, the non-physical work environment and transformational leadership had an effect on ASN work motivation. Non-physical work environments, transformational leadership, and work motivation partially affect ASN performance. Non- physical work environments affect ASN performance through work motivation. Transformational leadership affects ASN performance through work motivation.

Effect of the electrostatic field due to the surface monolayer metal atoms on the dissociation of homonuclear diatomic gases in gas-metal surface reactions

The present paper examines the role of an electrostatic field generated by the outermost monolayer of metal ions prior to gas adsorption in aiding the dissociation of homonuclear diatomic gas molecules. The interaction of five homonuclear diatomic gases, Cl2, F2, H2, N2 and O2, with several pure metals are examined using Coulomb's law to calculate the attractive and repulsive forces between the electrons or ions in the gas molecule and the free surface metallic electrons or ions assuming a Bohr model. These calculations demonstrate that the total energy of the electrostatic fields from the metals can exceed the molecular binding energies of Cl2, F2, and O2 at some distance from the metallic surface thereby suggesting that these gases interact primarily with the metallic surface in their atomic states after molecular bond dissociation prior to reaction. In contrast, H2 and N2 gases do not dissociate prior to reaching the metal surface due to the fact that the effective charge of the gas ions is less than the total electron charge at the outermost electronic shell. The present results correlate linearly with the electrochemical series standard reduction potential as well as with the Pauling electronegativity for several metals.

Ni2+ and Cu2+ complexes of N-(2,6-dichlorophenyl)-N-mesityl formamidine dithiocarbamate structural and functional properties as CYP3A4 potential substrates

Metal compounds continued to attract diverse applications due to their malleability in several capacities. In this study, we present our findings on the crystal structures and functional properties of Ni2+ and Cu2+ complexes of N'-(2,6-dichlorophenyl)-N-mesitylformamidine dithiocarbamate (L) comprising [Ni-(L)2] (1) and [Cu-(L)2] (2) with a four-coordinate metal center. We established the two complex structures through 1H and 13C nuclear magnetic resonance (NMR), elemental, and single-crystal X-ray analysis. The analyses showed that the two complexes are isomorphous, having P21/c as a space group and a unit-cell similarity index (π) of 0.002. The two complexes conform to a distorted square planar geometry around the metal centers. The calculated and experimental data, including bond lengths, angles, and NMR values, are similar. Hirshfeld surface analysis revealed the variational contribution of the different types of intermolecular contacts driven by the crystal lattice of the two solvated complexes. Our knowledge of the potential biological implication of these structures enabled us to probe the compounds as prospective CYP3A4 inhibitors. This approach mimics current trends in pharmaceutical design and biomedicine by incorporating potentially active molecules into various media to predict their biological efficacies. The simulations show appreciable binding of compounds 1 and 2 to CYP3A4 with average interaction energies of –97 and –87 kcal/mol, respectively. The protein attains at least five conformational states in the three studied models using a Gaussian Mixture Model-based clustering and free energy prediction. Electric field analysis shows the crucial residues to substrate binding at the active site, enabling CYP3A4 structure to function prediction. The predicted inhibition with these Ni2+ and Cu2+ complexes indicates that CYP3A4 overexpression in a diseased state like cancer would reduce, thereby increasing the chemotherapeutic compounds' shelf-lives for adsorption. This multidimensional study addresses various aspects of molecular metal electronics, including their application as substrate-mimicking inhibitors. The outcome would enable further research on bio-metal compounds of critical potential.

Triangular silver nanoplates-BiVO4 composite for the photocatalytic CO2 reduction under irradiating LED light source

In this study, triangular silver nanoplates (TagNPts)/BiVO4 nanomaterials were prepared by hydrothermal method and are used as a photocatalyst in a photoreaction system to convert carbon dioxide into methane and carbon monoxide. The as prepared material was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and ultraviolet–visible spectrometer (UV–vis). The absorbance increases in the visible light region due to the incorporation of nano-silver (triangular plate) metal and pulls electrons, reduces the recombination rate of electron-hole pairs, and improves the photoreduction activity. The transmittance ratio is measured and the specific wavelengths of blue LED 412–505 nm and green LED 427–622 nm are measured. It shows that the irradiation of targeted wavelength bands will increase the absorbance and effectively reduces the recombination of electron-hole pairs. The best performance in this study was achieved after irradiating blue light source with 0.9% TAgNPts/BiVO4. The cumulative production of photoreduced carbon monoxide is 30.11 μmol g−1 and the quantum yield is 0.07%. After a green light source, the cumulative carbon monoxide yield using 0.9 wt% TAgNPts/BiVO4 is 24.77 μmol g− and the quantum yield is 0.06%.

Quantum Confinement and Electronic Structure at the Surface of van der Waals Ferroelectric α-In2Se3.

Two-dimensional (2D) ferroelectric (FE) materials are promising compounds for next-generation nonvolatile memories due to their low energy consumption and high endurance. Among them, α-In2Se3 has drawn particular attention due to its in- and out-of-plane ferroelectricity, whose robustness has been demonstrated down to the monolayer limit. This is a relatively uncommon behavior since most bulk FE materials lose their ferroelectric character at the 2D limit due to the depolarization field. Using angle resolved photoemission spectroscopy (ARPES), we unveil another unusual 2D phenomenon appearing in 2H α-In2Se3 single crystals, the occurrence of a highly metallic two-dimensional electron gas (2DEG) at the surface of vacuum-cleaved crystals. This 2DEG exhibits two confined states, which correspond to an electron density of approximately 1013 electrons/cm2, also confirmed by thermoelectric measurements. Combination of ARPES and density functional theory (DFT) calculations reveals a direct band gap of energy equal to 1.3 ± 0.1 eV, with the bottom of the conduction band localized at the center of the Brillouin zone, just below the Fermi level. Such strong n-type doping further supports the quantum confinement of electrons and the formation of the 2DEG.

Investigation of heavy metal removal from salty wastewater and voltage production using Shewanella oneidensisMR‐1 nanowires in a dual‐chamber microbial fuel cell

AbstractHeavy metal removal and simultaneous energy production were studied using a dual chambered Microbial Fuel Cell inoculated with Shewanella oneidensis MR‐1 in the anode. Synthetic wastewater was prepared with Cu (II), Mg (II), Mn (II), Zn (II), Na, and Phenol based on desalter effluent from refinery processes at different metal concentrations. In this study, a maximum open‐circuit voltage of 517.6 mV was reached at Conc. 5 with wastewater in the anode chamber, and 127.7 mV at Conc. 3 was produced with synthetic wastewater in the cathode chamber. Moreover, μ at Conc. 5 was 0.1133 h−1, demonstrating bacterial growth under metal and phenol concentrations. The highest metal removal in the anode for Cu (II), Mg (II), Mn (II), Zn (II), and Na was 93%, 85%, 93%, 88%, and 36%, respectively. In the cathode chamber the removal of Cu (II), Mg (II), Mn (II), Zn (II), and Na was 98%, 49%, 57%, 59%, and 36%, respectively. During the operation in the anode, SEM images showed that the bacterial nanowires are formed in response to toxic and anaerobic environments which contribute to the bacterial growth. These nanowires increased the metal removal and the voltage production as a consequence of a higher electron rate from the anode to the cathode due to the higher extracellular membrane surface area. S. oneidensis is a bacterium with metal‐reducing characteristics, and it is suitable for metal removal and electron transport from carbon sources, demonstrated in voltage production with microbial fuel cells.

Weak Localization of Light in a Magneto-Active Medium

The interference contribution to the optical conductance (total transmittance) of a sample of a disordered Faraday medium is calculated. The suppression of wave interference in a magnetic field is shown to be due to helicity-flip scattering events. The magnetic field does not destroy the interference of waves with a given helicity, but suppresses it if the helicity changes along different parts of the wave trajectory. This leads to a decrease in the interference contribution to the conductance with increasing the magnetic field. A similar phenomenon, negative magnetoresistance, is known as a consequence of weak localization of electrons in metals with impurities. It is found that, as the magnetic field increases, the change in the interference correction to the optical conductance tends to a certain limiting value, which depends on the ratio of the transport mean free path to the helicity-flip scattering mean free path. We also discuss the possibility of controlling the transition to the regime of strong “Anderson” localization in the quasi-one-dimensional case by means of the field.

Intrinsic spin shielding effect in platinum-rare-earth alloy boosts oxygen reduction activity.

Oxygen reduction reactions (ORRs) involve a multistep proton-coupled electron process accompanied by the conversion of the apodictic spin configuration. Understanding the role of spin configurations of metals in the adsorption and desorption of oxygen intermediates during ORRs is critical for the design of efficient ORR catalysts. Herein, a platinum-rare-earth-metal-based alloy catalyst, Pt2Gd, is introduced to reveal the role of spin configurations in the catalytic activity of materials. The catalyst exhibits a unique intrinsic spin reconfiguration because of interactions between the Gd-4f and Pt-5d orbitals. The adsorption and desorption of the oxygen species are optimized by modifying the spin symmetry and electronic structures of the material for increased ORR efficiency. The Pt2Gd alloy exhibits a half-wave potential of 0.95V and a superior mass activity of 1.5 A·mgPt-1 in a 0.1M HClO4 electrolyte, as well as higher durability than conventional Pt/C catalysts. Theoretical calculations have proven that the spin shielding effect of Gd pairs increases the spin symmetry of Pt-5d orbitals and adsorption preferences toward spin-polarized intermediates to facilitate ORR. This work clarifies the impact of modulating the intrinsic spin state of Pt through the interaction with the local high spin 4f orbital electrons in rare-earth metals, with the aim of boosting the spin-related oxygen reduction reaction, thus fundamentally contributing to the understanding of new descriptors that control ORR activity.

Enhanced spin Seebeck effect via oxygen manipulation

Spin Seebeck effect (SSE) refers to the generation of an electric voltage transverse to a temperature gradient via a magnon current. SSE offers the potential for efficient thermoelectric devices because the transverse geometry of SSE enables to utilize waste heat from a large-area source by greatly simplifying the device structure. However, SSE suffers from a low thermoelectric conversion efficiency that must be improved for widespread application. Here we show that the SSE substantially enhances by oxidizing a ferromagnet in normal metal/ferromagnet/oxide structures. In W/CoFeB/AlOx structures, voltage-induced interfacial oxidation of CoFeB modifies the SSE, resulting in the enhancement of thermoelectric signal by an order of magnitude. We describe a mechanism for the enhancement that results from a reduced exchange interaction of the oxidized region of ferromagnet, which in turn increases a temperature difference between magnons in the ferromagnet and electrons in the normal metal and/or a gradient of magnon chemical potential in the ferromagnet. Our result will invigorate research for thermoelectric conversion by suggesting a promising way of improving the SSE efficiency.

Metal-Induced Fast Vibrational Energy Relaxation: Quantum Nuclear Effects Captured in Diabatic Independent Electron Surface Hopping (IESH-D) Method.

In this paper, we propose a simple approach to include quantum nuclear effects in the weak electronic coupling regime within the independent electron surface hopping (IESH) method for simulating nonadiabatic dynamics near metal surfaces. Our method uses electronic states in a diabatic basis, and electronic transitions between metal and molecular states are included using Landau-Zener theory. We benchmark our novel approach using a two-state model system for which exact results (obtained from Fermi's golden rule) are available. We further investigate the effect of metallic electrons on the rate and the pathway of vibrational energy relaxation.

Numerical simulation of the temperature field of T2 copper/304 steel dissimilar metal electron beam welding

ANSYS workbench finite element analysis software was adopted to simulate and study the thermal process of electron beam welding of T2 copper and 304 steel heterogeneous materials in this paper. A solid model was established according to the size of the specimens, and a double ellipsoidal moving heat source model of the temperature field of the specimens of the three-dimensional dynamic simulation was imposed. Copper and steel welding transient temperature field distribution pattern and molten pool morphology were studied, and the temperature field welding thermal cycle curve was analyzed. The results show that the peak temperature of the steel side is higher than the copper side, the morphology of the welding pool is basically biased toward the steel side, and the highest temperature during the welding process appears in the center of the weld on the steel side about 0.5 mm.

Impact of Commercial Sugar as a Substrate in Single-Chamber Microbial Fuel Cells to Improve the Energy Production with Bioremediation of Metals

Microbial fuel cells (MFCs) have emerged as a viable method for bioremediation of toxic metals while also producing energy. In this paper, we examine the issue of organic substrate as a source of metabolism for microbe growth in MFC, as well as its significance for metal ion degradation in tandem with energy production. This study focused on the use of commercial sugar as an organic substrate in a single-chamber MFC. The MFC was operated for 27 days, with the highest voltage of 150 mV achieved on day 12, and toxic metal bioremediation efficiencies of 89%, 76.45%, and 89.45% for Pb2+, Cd2+, and Hg2+, respectively. Every 24 hours, the organic substrate (sugar solution) was fed into the cell. This study’s mechanism of metal ion degradation and electron transport is also thoroughly described. In addition, some future views have been highlighted.

Transition metals based metalides TM-Janus-TM (where TM=Sc–Zn and Janus=F6C6H6); A theoretical study of nonconventional metalides with excellent static and dynamic nonlinear optical properties

Continuous progress is being made to bring forward the novel strategies for designing materials with excellent stability and exceptional nonlinear optical response. For the first time, 3d-transition series (Sc–Zn) is doped as source of excess electrons to design novel class of TM-JN-TM (TM = Sc–Zn) metalides based upon Janus-type all-cis1,2,3,4,5,6-hexafluorocyclohexane (JN) molecule. DFT calculations are performed at M06-2X/6-31+G(d,p) level of theory to explore the electronic and NLO properties of these complexes. The obtained novel metalides show excellent thermal stabilities than those of conventional alkalides and their interaction energies ranging from −3.50 to −88.33 kcal mol−1. Under the large facial polarization of JN, the valence electrons of transition metals (TM) on fluorine face serve as source of excess electron to TM metals on hydrogen face. With the excellent electronic stabilities, these complexes show significant decreased HOMO-LUMO gaps and, the performed NBO analysis also reveals their metalide character where the negative charge is observed at metal (TMH) on hydrogen face of complex C, D, G, H, and I. Among the designed metalides (TM-JN-TM), the significant first and second hyperpolarizability values of 2.43 × 106 au and 1.72 × 109 au are observed for Fe-JN-Fe complex. Simple excess electron complexes have better NLO response than that of true metalides. The observed dynamic first hyperpolarizabilities β(ω) values are much pronounced at smaller dispersion frequency (1064 nm). The frequency-dependent second hyperpolarizability γ(ω) value increased up to 5.75 × 1010 au for V-JN-V. At 1300 and 1900 nm, significant dynamic second hyperpolarizability γ(ω) values are observed. The scattering hyperpolarizability (βHRS) show significant value (2.0 × 107 au) for Fe-JN-Fe complex. We hope this work could open up new possibilities for NLO material design by using transition metals as source excess electron and, on the other hand, encourage greater experimental efforts in the laboratory to synthesize such stable compounds.

PhET’s Photoelectric Effect Simulation: Experiments and Analysis for Classroom Practice

This paper describes the use of the PhET simulator on the photoelectric effect to explore the behavior of electrons in metal when exposed to light with differing frequencies. Using this simulation, students can be able to observe variations in electron emission when changing various parameters such as intensity or frequency of light. This paper is experimental research to test the PhET simulator on the photoelectric effect in terms of the guiding relationship in the photoelectric effect. This also analyzed the PhET simulation for improvements in classroom activities.The main tool of this research is a computer capable of running the PhET simulation. It was found that all principles of the photoelectric effect are followed by the simulation. This includes if there is an emission of electrons, the relationship between the kinetic energy of the electron and frequency, and the relationship photoelectric current and light intensity. However, it was observed that there is no work function of the metals on the simulation and this can have an effect the prediction if there is an emission or not. The graphs generated of the simulation contains error because of the thick line graph. It would be better for classroom practice if these gaps are bridged and teachers manage to adopt the simulation.

Co/CoSe Junctions Enable Efficient and Durable Electrocatalytic Conversion of Polysulfides for High‐Performance Li–S Batteries

AbstractLithium–sulfur (Li–S) batteries are regarded as promising candidates for next‐generation energy storage systems. However, the slow kinetics and shuttle effects of polysulfides hinder their practical applications. Designing high‐efficiency catalysts to enhance the kinetics and suppress shuttling is one major task for the building of durable Li–S batteries. Here, a Co/CoSe junction is reported to catalyzepolysulfide conversion efficiently because the junction has metallic electron mobility and field‐enhanced catalytic activity. The mechanistic investigation reveals that the difference in the work functions of Co and CoSe rearranges the charge distribution in the junction and strengthens the interaction between polysulfides and CoSe, thereby yielding high catalytic activity. In addition, the relative stability of CoSe, as compared to Co, renders the junction durable upon cycling; therefore, demonstrating long‐term catalytic activity. Such a junction makes full use of metal‐like conductivity and field‐enhanced catalysis and provides an alternative approach to enhancing the catalytic conversion of polysulfides.

Preparation and mechanism analysis of nano-Mg(OH)2 by electroconversion of MgCl2

The preparation and application of porous laminated nanomaterials have been widely concerned because of their large surface area, abundant active sites, and enhanced mass transmission and diffusion. This study used a simple and economical method to synthesize metal hydroxide by the cationic membrane electroconversion synthesis method (CMESM). However, CMESM is not a typical metal electrodeposition process, it is a pseudoelectrolysis process, there is no gain or loss of metal electrons, but metal deposits will be generated. Therefore, its mechanism cannot be studied by conventional electrochemical methods. Thus, we change the research ideas, take the cheap and easy-to-obtain MgCl2·6H2O as raw material, use the chemical precipitation method and the cation membrane permeation method as comparative experiments, study the effect of different current densities on the product, and discuss the mechanism of CMESM. The results show that the Mg(OH)2 nanosheets are electric field induced and assembled into a three-dimensional porous layered petal structure with a large specific surface area and aperture. The metal hydroxides with low cost and high purity can be prepared by cationic membrane electrolytic synthesis.

Overcoming the PCBM/Ag Interface Issues in Inverted Perovskite Solar Cells by Rhodamine‐Functionalized Dodecahydro‐Closo‐Dodecaborate Derivate Interlayer

AbstractEfficient modification of the interface between metal cathode and electron transport layer are critical for achieving high performance and stability of the inverted perovskite solar cells (PSCs). Herein, a new alcohol‐soluble rhodamine‐functionalized dodecahydro‐closo‐dodecaborate derivate, RBH, is developed and applied as an efficient cathode interlayer to overcome the (6,6)‐phenyl‐C61 butyrie acid methyl ester (PCBM)/Ag interface issues. By introducing RBH cathode interlayer, the functions of the interface traps passivation, interfacial hydrophobicity enhancement, interface contact improvement as well as built‐in potential enhancement are realized at the same time and thus correspondingly improve the device performance and stability. Consequently, a power conversion efficiency (PCE) of 21.08% and high fill factor of 83.37% are achieved, which is one of the highest values based on solution‐processed MAPbI3/PCBM heterojunction PSCs. Moreover, RBH can act as a shielding layer to slow down moisture erosion and self‐corrosion. The PCE of the RBH devices still maintain 84% for 456 h (85 °C @ N2), 87% for 360 h (23 °C @ relative humidity (RH) 35%) of its initial PCE value, while the control device can only maintain ≈23%, 58% of its initial PCE value under the same exposure conditions, respectively.

Visualizing the atomic-scale origin of metallic behavior in Kondo insulators.

A Kondo lattice is often electrically insulating at low temperatures. However, several recent experiments have detected signatures of bulk metallicity within this Kondo insulating phase. In this study, we visualized the real-space charge landscape within a Kondo lattice with atomic resolution using a scanning tunneling microscope. We discovered nanometer-scale puddles of metallic conduction electrons centered around uranium-site substitutions in the heavy-fermion compound uranium ruthenium silicide (URu2Si2) and around samarium-site defects in the topological Kondo insulator samarium hexaboride (SmB6). These defects disturbed the Kondo screening cloud, leaving behind a fingerprint of the metallic parent state. Our results suggest that the three-dimensional quantum oscillations measured in SmB6 arise from Kondo-lattice defects, although we cannot exclude other explanations. Our imaging technique could enable the development of atomic-scale charge sensors using heavy-fermion probes.

Synergistic behavior between the plasmonic Ag metal and the mesoporous β-Bi2O3/SiO2 heterostructure for the photocatalytic destruction of bacterial cells under simulated sunlight illumination: Schottky junction electron-transfer pathway

Undoubtedly, one of the most attractive alternative wastewater disinfection techniques is visible-light-driven photocatalysis. Unfortunately, the fast recombination of charge carriers still limits its practical application. This limitation can be addressed by developing a plasmon-induced nanocomposite photocatalyst by hybridizing the semiconductor with co-catalyst metallic nanoparticles (NPs). Herein, a Schottky junction Ag/β-Bi2O3/SiO2 (A/BO/SO) nanocomposite was constructed via a multistep method involving the immobilization of β-Bi2O3 and Ag NPs on the nanosilica surface. The characterization techniques demonstrated the ability of Ag/β-Bi2O3/SiO2 to extend the visible light absorption and boost the charge separation efficiency through the plasmonic actions of silver metal. It was revealed that the Ag/β-Bi2O3/SiO2 nanocomposite exhibited improved antimicrobial performance against the Staphylococcus aureus pathogen, in which 7-log of bacterial cells were inactivated within 120 min under simulated solar light illumination. These outcomes were ascribed to the synergistic impact of silica support, β-Bi2O3 semiconductor, and plasmonic Ag metal (electron acceptor) in one system. Besides, the Ag/β-Bi2O3/SiO2 nanocomposite displayed remarkable structural stability after five inactivation cycles, which is attributed to the mesoporous structure of the silica support. The mechanism studies revealed that •OH and •O2− are the main reactive species that drive the disinfection reaction, and the electrons' separation behavior is well matched with Schottky junction pathways. In conclusion, this work provided an efficient and stable photocatalyst with minimum energy consumption that can be applied in water disinfection for the removal of pathogenic microorganisms.