Electron Energy Research Articles

Electron temperature measurement from neutral atomic tungsten emission line ratio.

A method to determine electron temperature within a plasma by the spectral analysis of atomic tungsten emission has been explored. The technique was applied to a post-discharge region immediately following a high voltage nanosecond pulsed discharge in air with tungsten electrodes. Atomic tungsten lines are readily observed in the weak emission spectrum within the post-discharge region for many microseconds. Intensity ratios were measured at various times after the pulsed discharge for a select pair of neutral tungsten emission lines at 400.88 and 401.52nm, where the upper electronic levels of each transition are at 3.46 and 5.52eV respectively. This significant difference in upper state energy causes their line intensity ratio to vary as the electron temperature changes. In addition to the emission spectra, the absolute electron temperature could be accurately measured in our lab using laser Thomson scattering to calibrate the new tungsten emission line intensity ratio method. An analysis is presented that calculates electron temperature from these tungsten emission data assuming a Maxwellian electron energy distribution contributing to direct electron impact excitation to the upper states of each transition. The results included the derivation of a calibration factor between the two experimental methods representing a previously unreported ratio of Einstein A coefficients for the 400.88-401.52nm transitions. This derivation provides a method for future measurement of absolute electron temperature by the 400.88-401.52nm tungsten line intensity ratio without the need for laser Thomson scattering calibration.

Erratum to: Modulation mechanism of electron energy dissipation on superlubricity based on fluorinated 2D ZIFs

Erratum to: Modulation mechanism of electron energy dissipation on superlubricity based on fluorinated 2D ZIFs

Electronic screening effects during bremsstrahlung of carbon atoms and ions

Bremsstrahlung, as an important radiation process in atomic physics, has significant applications in the fields of astrophysics, plasma physics, magnetic and inertial confinement fusion. In this work, the relativistic partial-wave expansion method is used to investigate the bremsstrahlung of neutral carbon atoms and different charged carbon ions scattered from intermediate- and high-energy relativistic electrons, with special attention paid to the electronic screening effect produced by the target electrons. The target wave function is obtained from the Dirac-Hartree-Fock self-consistent calculations, and the electron-atom scattering interaction potential is constructed in the central-field approximation. By solving the partial-wave Dirac equation, the continuum wave functions of the relativistic electron are obtained, from which the bremsstrahlung single and double differential cross sections can be calculated via the multipole free-free transitions between the incident and exit free electrons. The target electronic screening effects on the bremsstrahlung single and double differential cross sections are analyzed under a variety of conditions of incident electron energy and emitted photon energy. It is shown that the target electronic screening effect will significantly suppress the cross sections both at low incident energy and in the soft-photon region. Such a suppressing effect decreases with the incident electron energy and the emitted photon energy gradually increasing. Overall, the electronic screening effect has no significant influence on the shape function of bremsstrahlung.

Structural, electronic, mechanical, optical and magnetic properties of RhNbZ (Z = Li, Si, As) Half-Heusler compounds: a first-principles study

Abstract Structural, mechanical, electronic, optical and magnetic properties of the cubic RhNbZ (Z = Li, Si, As) half-Heusler compounds is reported using density functional theory (DFT) as implemented in quantum espresso simulation package. Structurally, the compounds are most stable when they are in type I atomic arrangement. Studies of mechanical properties indicate that all the three compounds are ductile in nature and mechanically stable. Calculations of electronic band structure and density of states (DOS) affirm that RhNbSi is a semi-conductor with an indirect band gap of 0.662 eV and 1.0095 eV from generalized gradient approximation (GGA) and GGA+U approaches respectively, where U is Hubbard parameter, RhNbLi has metallic property under both GGA and GGA+U approaches whereas RhNbAs has metallic nature under GGA prediction but it has half-metallic property under GGA+U approach, a property which is essential for spintronic applications. Optical parameters such as dielectric function, reflectivity, refractive index, extinction coefficient, absorption coefficient, optical conductivity and electron energy loss were estimated in the photon energy range of 0–40 eV. Results from these properties calculations reveal that both absorption coefficient and optical conductivity have maximum values whereas electron energy loss has minimum value in the lower energy ranges which show that the materials under our study can be considered as potential candidates for optoelectronic applications. From magnetic property calculations, RhNbSi is predicted to be nonmagnetic material but RhNbLi and RhNbAs have magnetic nature.

A Study on Corrosion Inhibition Effects Based on CS-NR Application Results on Leakage Accidents of Sprinkler Copper Pipes

Copper has better corrosion resistance than iron and good physical and chemical properties, including high electrical and heat conductivities. Therefore, it is widely used in various industrial applications. However, pitting corrosion occurs in the copper pipe of the sprinkler due to the oxygen concentration of the cell by the deposition of foreign substances on the inner side of the copper pipe, and leakage often occurs in the copper pipe due to the formation of shot holes. In this study, when a copper plate was submerged in a 3% NaCl solution for 10 days and the effects of the addition of CS-NR (6, 8, and 10 g) on corrosion protection were investigated by observing the surface conditions of the test specimen using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis by map the SEM results. The surface of the test specimen immerged only in the 3% NaCl solution without the addition of CS-NR exhibited pitting corrosion due to chloride ions. However, with the addition of CS-NR, pitting corrosion was not observed at the surface, regardless of the amount of CS-NR added. Furthermore, the addition of 8 g (8 × 10<sup>3</sup> ppm) of CS-NR resulted in the best corrosion resistance against pitting corrosion because the amount of oxygen and silicon that formed the protective film revealed an optimal mixed ratio as compared with 6 and 10 g of CS-NR.

Absorption, backscattering and transmission properties assessment of electrons and photons in BeO and NaCl materials by Monte Carlo method

The simulation by the Monte Carlo method has proved to be effective in highlighting the absorption properties, of backscattering and transmission when propagating 5 KeV electron beams through 150 µm thick of each of the BeO and NaCl materials. Despite the fact that a very small fraction of the primary electrons was transmitted in the materials, several microscopic phenomena occurred at the level of the electronic sub-layers. This is the characteristic line, fluorescence and bremsstrahlung. The energy of the incidence electrons was higher than that of the sub-shells of atoms in the materials studied. The sub-shells concerned were for oxygen: KL2, KL3, KM2, KM3, L3M1, L3M3, L2M1, L1M3, L1M2, chlorine: L1M2, sodium: KL2 and KL3. Due to their properties, the use of BeO and NaCl can improve performance in the manufacture of advanced technology devices such as synchrotron, clinical particle accelerator and X-ray tube.

Electron and hole energy spectrum of non-concentric spherical core-shell quantum dot under an externally applied electric field

A model of the non-concentric spherical core–shell quantum dot under the influence of an externally applied electric field was proposed. It was established that the energy spectrum of both the electron and the hole depends on the intensity of the electric field as well as on the specific location of the core within the quantum dot. The phenomenon of energy level splitting and degeneration was analyzed in detail. Additionally, the variations in the optical gap were determined and expressed as a function of the applied electric field strength and the position of the core in the quantum dot.

Bio-Preparation of Iron Nano Fertilizers from Lemon Fruit Affected some of the Characters of Carrot plants (Daucus carota L.)

To study the biological preparation of iron nano fertilizers from lemon fruit extract and their effect on some quantitative traits of carrot (Daucus carota L.) plant. Experiments were conducted, a laboratory part and a field part, with two addition factors, foliar fertilization and soil fertilization, using two sources of iron. The first source was nano-iron at a concentration of 0.5, 1, 1.5, and 2 mg L-1, and the second source was chelated iron at a concentration of 1.5 g L-1 and control treatment. The results showed the superiority of foliar fertilization in most of the studied traits such as iron concentration, root length, root diameter, fresh weight, dry weight, carotene and total dissolved solids (144.30 ppm, 17.10 cm, 2.1 cm, 137.98 g, 16.03 g, 1.62 mg g fresh weight-1 and 8.79 %, respectively). Nano-iron spraying was superior than to chelated iron in the concentration of iron (Fe), root length, root diameter, fresh weight, dry weight, and total dissolved solids (1059.22 ppm, 20.82 cm, 2.29 cm, 168.97 g, 18.37 g, and 9.91 %, respectively). X-ray diffraction (XRD) was used to determine the size and purity of the nanoparticles, and scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to verify the composition. Iron oxide (Fe2O3) was in the form of α-Fe2O3 hematite with a size of 32.8 nm and Ỵ-Fe2O3 maghematite with a size of 44.6 nm. We conclude that the use of green synthesis method for nano-fertilizers has proven effective and efficient from an economic and environmental point of view.

ANALYSIS OF SINTERED ZrXEr1-X OBTAINED THROUGH POWDER METALLURGY

This paper aims to analyze Zr-Er sintered compounds obtained through powder metallurgy, with different concentrations, able to store H2. To obtain Zr-Er sintered compacts, in the first phase, zirconium and erbium were hydrides separately, at 750°C in a hydrogen atmosphere, for two hours each, to obtain zirconium and erbium hydrides. Using XRD analysis, both zirconium and erbium formed ErH3 and ZrH2. After the mechanical processing, morphological analysis performed by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS) revealed microparticles with sizes ranging from 8.08 µm to 27.16 µm for ZrH2, 3.72 µm to 17.86 µm for ErH3. The mixtures of hydride powders were pressed in a cylindrical mold, and two ZrxEr1-x(x=0.25;0.75) pressed compacts were obtained. These samples were subjected to a heat treatment, in a helium atmosphere, that included a dehydrogenation treatment, followed by a sintering treatment, at 1200°C, for two hours. The compounds obtained were geometrically characterized, their experimentally determined density being more than 90% of their calculated density. SEM analysis of the sintered compounds revealed a densification of zirconium and erbium particles, and also, the higher the zirconium content, the more pores the sintered sample has. SEM-EDS microstructural analysis shows a uniform distribution of the component elements, and an increased tendency of erbium to oxidize.

Analysis of plasmon modes in Bi2Se3/graphene heterostructures via electron energy loss spectroscopy

Topological Insulators (TIs) are promising platforms for Quantum Technology due to their topologically protected surface states (TSS). Plasmonic excitations in TIs are especially interesting both as a method of characterisation for TI heterostructures, and as potential routes to couple optical and spin signals in low-loss devices. Since the electrical properties of the TI surface are critical, tuning TI surfaces is a vital step in developing TI structures that can be applied in real world plasmonic devices. Here, we present a study of Bi2Se3/graphene heterostructures, prepared using a low-cost transfer method that reliably produces mono-layer graphene coatings on Bi2Se3 flakes. Using both Raman spectroscopy and electron energy loss spectroscopy (EELS), we show that the graphene layer redshifts the energy of the plasmon mode in Bi2Se3, creating a distinct surface plasmon that differs significantly from the behaviour of a TI-trivial insulator boundary. We demonstrate that this is likely due to band-bending and electron transfer between the TI surface and the graphene layer. Based on these results, we outline how graphene overlayers can be used to create tuneable, stable plasmonic materials based on topological insulators.

Novel Insights into Enhanced Stability of Li-Rich Layered and High-Voltage Olivine Phosphate Cathodes for Advanced Batteries through Surface Modification and Electron Structure Design.

The design of cathode/electrolyte interfaces in high-energy density Li-ion batteries is critical to protect the surface against undesirable oxygen release from the cathodes when batteries are charged to high voltage. However, the involvement of the engineered interface in the cationic and anionic redox reactions associated with (de-)lithiation is often ignored, mostly due to the difficulty to separate these processes from chemical/catalytic reactions at the cathode/electrolyte interface. Here, a new electron energy band diagrams concept is developed that includes the examination of the electrochemical- and ionization- potentials evolution upon batteries cycling. The approach enables to forecast the intrinsic stability of the cathodes and discriminate the reaction pathways associated with interfacial electronic charge-transfer mechanisms. Specifically, light is shed on the evolution of cationic and anionic redox in high-energy density lithium-rich 0.33Li2MnO3·0.67LiNi0.4Co0.2Mn0.4O2 (HE-NCM) cathodes, particularly those that undergo surface modification through SO2 and NH3 double-gas treatment to suppress the structural degradation. The chemical composition and energy distribution of the occupied and unoccupied electronic states at the different charging/discharging states are quantitatively estimated by using advanced spectroscopy techniques, including operando Raman spectroscopy. The concept is successfully demonstrated in designing artificial interfaces for high-voltage olivine structure cathodes enabling stable battery operation up to 5.1V versus Li+/Li.

Mode transition in a helium barrier discharge with oxygen admixtures: insights into a micro cavity plasma array reactor

Abstract Dielectric barrier discharges (DBDs) offer great potential for applications such as volatile organic compounds (VOCs) conversion or plasma catalysis. For many of these applications, an admixture of molecular oxygen is important, for example, to oxidize the gases to be treated. However, oxygen addition can lead to a drastic change in discharge dynamics, which may affect conversion efficiency. The discharge may transition to a filamentary mode, which could influence plasma chemical processes or in extreme cases potentially damage the reactor. This study investigates the discharge mode of a micro cavity plasma array operated at atmospheric pressure with a helium flow (1–2 slm) containing small oxygen admixtures (0%–5%). A multitude of parameters as voltage, current, power, and emission are investigated for characterization. Additionally, the electric field, mean electron energy and atomic oxygen density are examined depending on the oxygen admixture. With pure helium, a homogeneous atmospheric pressure glow discharge is observed, appearing as a quasi-continuous glow discharge. With small oxygen admixtures (0.1%–1%), individual discharge pulses become visible, though they remain separated (pseudo glow discharge). At higher oxygen admixtures ( ⩾ 1%), a mode transition to a filamentary discharge is observed. The measurements indicate that the discharge mode, especially the individual discharge pulses, has a significant impact on conversion efficiency. This knowledge can help in the future to fine-tune the discharge mode using external parameters such as voltage waveform or frequency to optimize conversion efficiency.

Effects of nozzle geometry, compression ratio and cerium oxide nanoparticles on algae biodiesel performance in a VCR diesel engine with hydrogen addition

This paper discusses an exploratory analysis of performance and emissions characteristics of a variable compression ratio (VCR) diesel engine using various compression ratios, nozzle hole configurations, and injection timings. Results will be employed to further elucidate interactions among those parameters as well as their influence upon the operation efficiency and environmental output. An engine was tested on the B20 biodiesel blend from the transesterification of algal oil. The sample, which contained nano-additives with cerium oxide (CeO2) at a concentration of 75 ppm, underwent extensive analysis using scanning electron microscopy and energy dispersive X-ray analysis (FTIR). The study included different compression ratios such as 16:1, 17:1, 18:1, and 19:1, utilizing nozzle designs with hole diameters of 2, 3, 4, and 5 mm. Additionally, it also examines the effects of hydrogen injection at time intervals of 3, 4, and 5 ms, aiming to comprehend the interaction between these parameters and their impact on the performance outcome. The presence of CeO2 75 ppm resulted in a significant reduction in emissions, as well as improved combustion efficiency. The configuration resulted in a 6.1% improvement in brake thermal efficiency (BTE), as well as a decrease in brake specific fuel consumption (BSFC) from 250 g/kWh to 200 g/kWh. Improving the number of holes in the nozzle revealed a drop in the temperature of the exhaust gas up to 250°C. Reduced nitrogen oxide (NOX) emissions and improved cylinder pressure accompanied these decreases, thanks to the increased heat release rates generated by hydrogen addition. The addition of CeO2 nanoparticles to the B20 blended fuel, along with modifications to the nozzle hole design and hydrogen injection, not only reduces emission values but also lowers fuel consumption, lowers exhaust gas temperature (EGT), and improves combustion efficiency.

Size Dependence of the Band Gap of Core-Shell Tantalum and Tantalum Oxide (V) Nanoclusters.

Monodisperse films of spherical tantalum oxide (V) nanoclusters and spherical tantalum nanoclusters with a tantalum oxide shell with diameters of 1.4-8 nm were obtained by magnetron sputtering. The size of the deposited nanoclusters was controlled using a quadrupole mass filter. The chemical composition was certified using the XPS method. Using the Reflected Electron Energy Loss Spectroscopy (REELS), the dependence of the band gap width on the nanocluster size was determined. It was found that starting from a certain nanocluster size, the band gap width increases as the nanocluster size decreases. Based on experimental data and a theoretical model, the effective mass of electrons dependence as a function of nanocluster size was obtained.

Hollow Salt Prepared Through Spray Drying with Alginate Enhances Salinity Perception to Reduce Sodium Intake.

Currently, high-salt diets have become one of the world's biggest dietary crisis and long-term high-salt diets are seriously detrimental to human health. In response to this situation, the present study proposed a saltiness enhancement strategy using alginate, which is a dietary fibre from brown algae and has many health benefits, such as regulating intestinal microbiota, anti-hypertension and anti-obesity. The comparison of alginates with different viscosities showed that alginate of 1000-1500 cps at a concentration of 1.25 g/L could enhance the saltiness of NaCl solution by 11.5%. Then, a solid salt was prepared through spray drying with 4.83% of this alginate, and its structure was characterised by X-Ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive spectroscopy to confirm its hollow structure with a particle size of 6.25 ± 2.26 μm as well as its crystal structure similar to original NaCl. Moreover, the conductivity monition revealed that the hollow salt exhibited a more rapid dissolution in water and its alginate component increased the adhesive retention of sodium ions on the tongue surface, which both effectively enhanced the sensory perception. Finally, as revealed by the sensory evaluation, the prepared hollow salt showed higher saltiness than that of original table salt and it could reduce sodium intake by 29%. Thus, the hollow salt prepared with alginate in the present study has potential for salt reduction.

ENHANCEMENT OF POWER CONVERSION EFFICIENCY OF DYE-SENSITIZED SOLAR CELLS VIA INCORPORATION OF GAN SEMICONDUCTOR MATERIAL SYNTHESIZED IN HOT-WALL CHEMICAL VAPOR DEPOSITION FURNACE

This study discusses the results of plasma enhanced chemical vapor deposition synthesis of GaN on sapphire and silicon substrates using specific parameters: a forward output voltage of 150 watts, a N2 gas flow rate of 60 standard cubic centimeters per minute, a chamber pressure of 2.48 mmHg, and a synthesis time of 2hours. Characterization by scanning electron microscope, Raman and energy dispersive X-ray revealed the non-stoichiometric formation of GaN, with Ga clearly predominating in the composition. scanning electron microscope analysis of the substrate surface morphology revealed the presence of small islands, which are considered to be the first step in the chemical vapor deposition process. The research also examined the effects of incorporating GaN into the photoanode of dye-sensitized solar cells. The study investigated the optimal amount of GaN powder in the TiO2 matrix. The initial experiments used commercial GaN powder to determine the optimal weight percentage. Four different weight percentages (wt%) 10 wt%, 20 wt%, 30wt % and 40 wt% GaN were selected for the study. Among them, the 20 wt% GaN had the highest power conversion efficiency of 0.75%. The fill factor values ​​showed a tendency to decrease as the weight fraction of GaN increased.

Advancements in Ge-based thermoelectric materials for efficient waste heat energy conversion: a comprehensive review

Abstract Thermoelectric materials hold significant promise for converting waste heat energy into electrical energy. The performance of these materials and devices is assessed using a quantitative measure known as the figure of merit, which relies on the Seebeck coefficient, thermal conductivity, and electrical conductivity of the material. Different classes of thermoelectric materials have their own merits and demerits. High temperature thermoelectric materials are useful for space exploration, automobile applications, etc Many materials have been explored within temperature range of 300–900 K, showing suitable properties for thermoelectric applications. Germanium, an inorganic material is investigated in details, due to its high Seebeck coefficient and better thermal stability. Silicon-Germanium alloys are thermoelectric materials suitable for operating at high temperatures. These materials help in reduction of emission of green house gases. Extensive efforts have been devoted to enhance the efficiency of Germanium-based thermoelectric materials and devices through various techniques such as doping, nanostructuring, electron energy filtering, and band engineering. Recently, a new material Ge0.94Sm0.06Te has been introduced, reporting a high figure of merit value of 2.5 at 730 K. Many theoretical studies are also reported showing the potential of new Germanium-based thermoelectric materials. Further, 2D Germanium-based materials show enhanced thermoelectric properties as well. These findings underscore the significance of Germanium as a thermoelectric material. This review provides an overview of the latest developments in Germanium-based thermoelectric materials and focuses on different strategies to enhance their thermoelectric performance. Additionally, the suitability of various Germanium-based thermoelectric materials in comparison to other materials for energy harvesting applications is extensively discussed in this review.

Correlation of Laser-Accelerated Electron Energy with Electromagnetic Pulse Emission from Thin Metallic Targets

High-power pulsed lasers are used more and more as tools for particle acceleration. Characterization of the accelerated particles in real-time and monitoring of the electromagnetic pulses (EMPs) during particle acceleration are critical challenges in laser acceleration experiments. Here, we used the CETAL-PW laser facility at NILPRP for particle acceleration from different thin metallic targets, at laser intensities of the order of 3×1021 W/cm2. We investigated the dependence of EMP amplitude (EMPA) and the accelerated electrons’ maximal energy (AEME), on thickness, resistivity, and atomic number of the target. We have found a quasi-linear dependence between EMPA and AEME and propose an analytical model for the GHz EMP emission. The model considers the neutralization current flowing through the target stalk as the main source of the EMP in the GHz domain, the current being produced by the positive charge accumulated on the target after the electron’s acceleration from the rear side of a metallic target. The data presented here support the possibility of using EMP signals to characterize the laser-accelerated particles in a real-time non-invasive way.

Distinguishing Charged Lepton Flavor Violation Scenarios with Inelastic μ→e Conversion

The Mu2e and COMET experiments are expected to improve existing limits on charged lepton flavor violation (CLFV) by roughly 4 orders of magnitude. μ→e conversion experiments are typically optimized for electrons produced without nuclear excitation, as this maximizes the electron energy and minimizes backgrounds from the free decay of the muon. Here we argue that Mu2e and COMET will be able to extract additional constraints on CLFV from inelastic μ→e conversion, given the Al27 target they have chosen and backgrounds they anticipate. We describe CLFV scenarios in which inelastic CLFV can induce measurable distortions in the near-endpoint spectrum of conversion electrons, including cases where certain contributing operators cannot be probed in elastic μ→e conversion. We extend the nonrelativistic EFT treatment of elastic μ→e conversion to include the new nuclear operators needed for the inelastic process, evaluate the associated nuclear response functions, and describe several new-physics scenarios where the inelastic process can provide additional information on CLFV. Published by the American Physical Society 2024

Solvent-free synthesis of an efficient heterojunction Cr2O3/g-C3N4 composites for the photocatalytic removal of TC-HCl antibiotic and RO16 dye.

Cr2O3/g-C3N4 photocatalyst was successfully synthesized via the one-pot thermal polycondensation method by mixing different ratios of CrCl3.H2O and thiourea. Thiourea was used as the precursor for building g-C3N4. All samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDS), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and electrochemical experiment (photocurrent and EIS). The photocatalytic performance of the composites was studied by the photodegradation process of tetracycline hydrochloride (TC-HCl) and reactive orange 16 (RO16) under visible light irradiation. The results showed that the 1%Cr2O3/g-C3N4 was the most effective photocatalyst with 94.9% (30min) and 80.6% (90min) for degradation of RO16 and TC-HCl, respectively, when compared with the other ratios. Additionally, from the reactive species trapping test, superoxide radical was the major reactive species in this reaction. Finally, this material could be reused with great efficiency with 5 and 7 times for TC-HCl and RO16, respectively. The synthesized composites manifest the great potential for the wastewater treatment industry.