Zone Diagram Research Articles

Evolution of blockchain accounting literature from the perspective of CiteSpace (2013–2023)

Against the backdrop of the Industrial Revolution 4.0, the advantages of blockchain technology in traceability, transparency, safety improvement, and efficiency improvement have made it possible to reduce the work of accounting personnel by 50 %, thus saving billions of dollars for global companies by combining this technology with accounting. However, the blockchain technology associated with accounting is in the experimental stage and has several problems to be solved including limited data processing capacity, information confidentiality, and regulatory difficulties. This innovation and progress in science and technology has provided more abundant, efficient, and professional technical support for the research of blockchain accounting documents. Among these advances, CiteSpace software has promoted the development of blockchain and accounting in the direction of visualization, comprehensiveness, security, and relevance. In this study, we used the knowledge map drawn by CiteSpace to search the core Blockchain Accounting database from 2013 to 2023 on the Web of Science (WoS). We obtained 1414 documents measured according to co-citation analysis, log-likelihood ratio (LLR) network clustering, co-occurrence keywords, and emergent time zone diagram method. We analyzed and summarized the important documents, research keywords, key research fields, and knowledge evolution related to "blockchain accounting" by network, literature integration, and popular research topics. We found that adopting blockchain technology in accounting information systems is expected to improve recordkeeping and reporting. Blockchain, as an innovative technology, provides a tamper-proof, traceable, and shareable platform for accounting information by using a distributed ledger system. By implementing blockchain, artificial intelligence can improve safety, transparency, and accuracy, and also may completely change the way we manage financial records. With its ability to improve overall efficiency and reduce errors, blockchain technology may change our familiar accounting methods. In addition, blockchain technology, intelligent contract, artificial intelligence, the Internet, information systems, and supply chain are the most important keywords, while blockchain technology, intelligent contract, and artificial intelligence are important components of blockchain accounting knowledge system. This research provided an important opportunity to advance the understanding of the crucial contribution of blockchain to the accounting field.

A hybrid plasma model for Cr thin film deposition by deep oscillation magnetron sputtering

A time-dependent hybrid plasma model composed of a zero-dimensional global model and a two-dimensional fluid model is proposed for simulation of plasma chemistry and transportation of plasma during Cr thin film deposition by deep oscillation magnetron sputtering (DOMS). The global model deals with plasma reactions in the ionization region near the target with discharge voltage and current waveforms as inputs. The temporal plasma characteristics calculated by the global model are utilized as a boundary condition for the two-dimensional fluid model to simulate high-density plasma transportation in the diffusion region through the entire macropulse period. The full momentum equation taking inertia force into consideration is applied for ion momentum conservation in the fluid model instead of using the drift-diffusion approximation, which ensures validity of the simulation for low-pressure plasmas. The deposition flux as well as the kinetic and potential energy fluxes transferred to the growing films are calculated by the hybrid model. Microstructure evolution of the DOMS deposited Cr thin films from zone I to zone T is attributed to the growing kinetic and potential energies as the charging voltage increases according to the structure zone diagram. The deposition rate loss in DOMS is explained by the back attraction effect, sputtering yield effect, and densification of the films.

Depletion of Electroactive Species in Microchannels. Theory and Experimental Validations for Quantitative Abatement of Interfering Species under Stagnant Conditions

The generation of an electroactive-species depleted microenvironment was investigated by taking advantage of confinement in microchannels under stagnant conditions. High depletion rates can be achieved with paired microband electrodes but the time scale of experiment must be carefully delimited based on device geometry, electrochemical cell configuration and species diffusivity. Numerical simulations were thus carried out to reach the situation of interest when the diffusion coupling and lateral diffusion in the microchannel becomes predominant with the operation of the electrodes. The optimal conditions for two minimal cell configurations (i.e., with two or three working electrodes) were delineated by establishing a zone diagram. Experimental validations were successfully performed (i) to illustrate the depletion rate achieved between two side electrodes, and (ii) to demonstrate the selective detection of a target analyte in presence of interfering species by using three electrodes. These situations can easily be extrapolated to the case of regular microelectrode arrays within microchannels.

Temperature zone diagram method for designing the total site exchanger network

Temperature zone diagram method for designing the total site exchanger network

Insights into Ionic Liquids for Flame Retardant: A Study Based on Bibliometric Mapping

Fire is a typical disaster in the processing industry. Ionic liquids, as a type of green flame retardant, play an important role in process safety. In order to grasp the current research status, hotspots, and frontiers in the field of ionic liquids in flame retardancy, the bibliometric mapping method is applied to study the relevant literature in Web of Science datasets from 2000–2022 in this paper. The results show that the research on ionic liquids in flame retardancy is multidisciplinary and involves some disciplines such as energy science, material science, and environmental protection. Journal of Power Sources, Polymer Degradation and Stability, ACS Applied Materials and Interfaces, and Chemical Engineering Journal are the core journals in the field. The results of keyword co-occurrence indicate that the hotspots of research can be divided into five components: the improvement and application of pure ionic liquids electrolytes, the research of gel polymer electrolytes, applying ionic liquids to enhance the polymer materials’ flame retardancy properties, utilizing ionic liquids and inorganic materials to synergize flame retardant polymers, and using ionic liquids flame retardant to improve material’s multiple properties. The burst terms and time zone diagram’s results point out the combination of computational quantum chemistry to study the flame retardancy mechanism of ionic liquids, the study of fluorinated electrolytes, ionic liquids for smoke suppression, phosphorus-containing ionic liquids for flame retardant, and machine learning-assisted design of ILs flame retardants are the research frontiers and future research trends.

Lewis Acids and Electron-Withdrawing Ligands Accelerate CO Coordination to Dinuclear CuI Compounds.

A series of dinuclear molecular copper complexes were prepared and used to model the binding and Lewis acid stabilization of CO in heterogeneous copper CO2 reduction electrocatalysts. Experimental studies (including measurement of rate and equilibrium constants) and electronic structure calculations suggest that the key kinetic barrier for CO binding may be a σ-interaction between CuI and the incoming CO ligand. The rate of CO coordination can be increased upon the addition of Lewis acids or electron-withdrawing substituents on the ligand backbone. Conversely, Keq for CO coordination can be increased by adding electron density to the metal centers of the compound, consistent with stronger π-backbonding. Finally, the electrochemically measured kinetic results were mapped onto an electrochemical zone diagram to illustrate how these system changes enabled access to each zone.

Optimization of mooring line design parameters using Mooring Optimization Tool for FPSO (MooOpT4FPSO) with the consideration of integrated design methodology

Optimization of mooring line design parameters including line azimuth angles, line diameter, line length and mooring radius is presented for a turret-moored FPSO. The optimization procedure is implemented using a Mooring Optimization Tool for FPSO (MooOpT4FPSO), which is an in-house optimization tool purposely developed for this purpose. The tool is a synchronisation of the Regrouping Particle Swarm Optimization (RegPSO) algorithm with commercial software, OrcaFlex. Case studies using a validated numerical FPSO model moored with multicomponent mooring lines acted upon by non-collinear wave, wind and current were analysed using the developed tool. To take into consideration the interaction of the riser system in the optimization procedure, the integrated design methodology was adopted where the riser safe operation (SAFOP) zone diagram combined with the offset diagram is used for the verification/assessment of the design criteria of the risers and mooring lines. The optimized FPSO model offsets in eight directions are found to be within the riser safe operation zone. Based on the results, the tool was able to simultaneously optimise the mooring line diameter, line length, mooring radius, and azimuth angles of the turret FPSO to achieve a specific offset. Application of the tool can help the industry save material (by reduction of line diameter and length) and consequently the overall project cost, in addition to the reduction of structural payload exerted on the platform. Furthermore, the tool has an automatic search capability, which is an improvement to the conventional mooring design approach that is based on a trial-and-error approach.

Photoinduced Charge Transfer from Quantum Dots Measured by Cyclic Voltammetry.

Measuring and modulating charge-transfer processes at quantum dot interfaces are crucial steps in developing quantum dots as photocatalysts. In this work, cyclic voltammetry under illumination is demonstrated to measure the rate of photoinduced charge transfer from CdS quantum dots by directly probing the changing oxidation states of a library of molecular charge acceptors, including both hole and electron acceptors. The voltammetry data demonstrate the presence of long-lived charge donor states generated by native photodoping of the quantum dots as well as a positive correlation between driving force and rate of charge transfer. Changes to the voltammograms under illumination follow mechanistic predictions from the ErCi' zone diagram, and electrochemical modeling allows for measurement of the rate of productive electron transfer. Observed rates for photoinduced charge transfer are on the order of 0.1 s-1, which are distinct from the picosecond dynamics measured by conventional transient optical spectroscopy methods and are more closely connected to the quantum yield of light-mediated chemical transformations.

Voltammetric Behaviour of LMO at the Nanoscale: A Map of Reversibility and Diffusional Limitations.

Understanding and optimizing single particle rate behaviour is normally challenging in composite commercial lithium-ion electrode materials. In this regard, recent experimental research has addressed the electrochemical Li-ion intercalation in individual nanosized particles. Here, we present a thorough theoretical analysis of the Li+ intercalation voltammetric behaviour in single nano/micro-scale LiMn2 O4 (LMO) particles, incorporating realistic interactions between inserted ions. A transparent 2-dimensional zone diagram representation of kinetic-diffusional behaviour is provided that allows rapid diagnosis of the reversibility and diffusion length of the system depending on the particle geometry. We provide an Excel file where the boundary lines of the zone diagram can be rapidly recalculated by setting input values of the rate constant, and diffusion coefficient, . The model framework elucidates the heterogeneous behaviour of nanosized particles with similar sizes but different shapes. Hence, we present here an outlook for realistic multiscale modelling of real materials.

A physically-based modelling to predict the cyclic voltammetry response of LSCF-type electrodes: Impact of the Ohmic Losses and Microstructure

Two numerical models have been developed to simulate the Cyclic Voltammetry (CV) response of Lanthanum Strontium Cobalt Ferrite (LSCF) porous electrode at high temperature. The first one (model-I) takes into account the solid-state diffusion in LSCF coupled with a global reaction of oxygen exchange while the second one (model-II) is based on a detailed elementary description of the reaction mechanism. The relevance of model-II to predict the voltammograms has been checked with experimental data obtained at different operating temperatures and imposed scan rates. The CV response of porous and quasi-dense electrodes has been studied with the two models and has been discussed in the frame of the zone diagram method. It has been shown that the peaks of the voltammograms are due to the transient change of the oxygen stoichiometry in LSCF. As this evolution is mainly governed by the oxygen diffusion in the material coupled to the reaction of oxygen exchange, it has been established that model-I can provide a satisfactory approximation of the CV curves if the exchange rate constant kchem is determined far from equilibrium. It has been also shown that the voltammograms are strongly distorted by the Ohmic losses making their interpretation impossible in practice, under the classical operating conditions of the solid oxide cells. To overcome this limitation, a methodology based on the modelling approach has been proposed to remove the Ohmic losses from the voltammograms and hence to reveal the voltammetry peaks. Finally, the impact of the LSCF decomposition on the CV response has been estimated with model-II. It has been established that the surface passivation and the decrease of the chemical diffusivity can substantially affect the shape of the voltammograms.

Impact of Zr content on the nanostructure, mechanical, and tribological behaviors of β-Ti-Nb-Zr ternary alloy coatings

Recent studies have dealt with Ti-based alloy coatings produced by magnetron sputtering that have promising characteristics as surface modification treatments for biomedical applications. Ti, Nb, and Zr are non-toxic and non-allergenic biocompatible metals, and the addition of Nb and Zr to Ti favored the mechanical compatibility between the alloy and the bone. In the present study, the effects of Zr content on the phase formation, morphology, texture, film growth, and mechanical and tribological properties were investigated. The coating with lower Zr content (5 at.%) presented two phases: mainly the β (body centered cubic) phase and nanoscale precipitates of the athermal ω phase, and the presence of this ω phase counted for higher values of both the elastic modulus and hardness. The increase in the Zr content yielded the stabilization of the β phase, and an increase in both the lattice parameter and the mean grain size, which caused a decrease in both the elastic modulus and hardness of the coatings. The increase in the Zr content also influenced the coating morphology, going from a growth characteristic of the zone I to a growth characteristic of the zone T of the structure zone diagram. Tribological tests revealed that changes in texture could bring about the deformation of the grains in the {101} orientation, causing the increase of the worn volume. No delamination of the coatings was observed. These findings indicate that the Ti-Nb-Zr ternary alloy coatings are adequate for biomedical applications.

Effect of cooling rate on microstructure and microhardness of hypereutectic Al–Ni alloy

High solidification cooling rates during unsteady-state conditions of solidification of Al-based alloys can induce different microstructural length scales or metastable phases, leading to improved properties. The present study aims to characterize the microstructural arrangement of the hypereutectic Al–8 wt%Ni alloy, unidirectionally solidified in unsteady-state heat flow conditions, examining the influence of the cooling rate in the development of the Al–Al3Ni eutectic and the primary phase. A columnar-to-equiaxed macrostructural transition is shown to occur at a solidification cooling rate (Ṫ) of about 4.8 °C/s, with different microstructures associated with each morphological zone. The observation of microstructures of hypoeutectic, eutectic and hypereutectic Al–Ni alloys, has permitted an asymmetric coupled zone diagram to be proposed. The microstructural interphase spacings of the Al–8 wt%Ni alloy are experimentally determined and correlated to Ṫ, and the Vickers microhardness (HV) is shown to decrease with the increase in such spacings. The higher experimental HV profile of the examined hypereutectic alloy as compared to that of the eutectic Al–Ni alloy is attributed to the formation of a supersaturated solid solution of Ni in α-Al.

Linear sweep and cyclic voltammetry of porous mixed conducting oxygen electrode: Formal study of insertion, diffusion and chemical reaction model

The classical 1D continuum model of oxygen exchange in a porous mixed conductor (bulk path) is presented in terms of Linear Sweep Voltammetry (LSV) and Cyclic Voltammetry (CV). We show that, from a formal point of view, it corresponds to an insertion, diffusion and chemical reaction mechanism. Some general rules for LSV/CV curves are established. Using a dimensionless description, we evidence eight different limiting behaviors of the electrochemical model, which depend on four dimensionless parameters. For an almost full insertion level at equilibrium, these parameters can be reduced to only two, i.e. the dimensionless electrode thickness L and the dimensionless chemical rate constant λ. We show that the resulting zone diagram, plotted using the representation log L versus log λ, is useful to predict the possible sequences of model behaviors as a function of the potential sweep rate and the electrode thickness. This theoretical analysis is applied to a porous LSCF oxygen electrode under air at high temperature.

Electrocatalytic Mechanism for Improving Sensitivity and Specificity of Electrochemical Nucleic Acid-Based Sensors with Covalent Redox Tags-Part I.

The design and development of advanced electrocatalysis have been extensively explored for efficient energy conversion and electrochemical biosensing. Both ferricyanide (Fe(CN)63-) and methylene blue (MB) have been widely used in the development of electrochemical biosensing strategies. However, the electrocatalytic mechanism between nucleic acid-tethered MB and Fe(CN)63- remains unexplored. In this manuscript, we aim to provide readers in our community molecular insights into the electrocatalytic mechanism. The exploration of the electrocatalytic mechanism starts with a kinetic zone diagram for a one-electron homogeneous electrocatalytic reaction. Two factors-the excess factor γ and the kinetic parameter λ-are important for a homogeneous electrocatalytic reaction; as such, we studied both. The excess factor parameter was controlled by applying Fe(CN)63- with various concentrations (50, 100, and 200 μM), and the kinetic parameter effect on the electrocatalytic process was examined by varying scan rates of cyclic voltammetry (CV) or frequencies of square-wave voltammetry (SWV). Moreover, we discovered that the probe dynamics of the nucleic acid tether is the third rate-limiting factor for the electrocatalytic reaction. As the probe dynamics switch of electrode-bound nucleic acid is often utilized as a mechanism in electrochemical nucleic acid-based sensors, we believe the electrocatalysis between nucleic acid-tethered MB and Fe(CN)63- is capable of enhancing sensitivity and specificity of electrochemical nucleic acid-based sensors with covalent redox tags.

From the anomalous diffusion impedance to the closed-form, infinite-series and integral formulations of the voltammetric response of thin-film insertion materials under restricted diffusion conditions. A modelling contribution based on the anomalous mass transfer function

Abstract The voltammetric response of one-step reversible electrochemical reactions (involving dissolved redox species) to a linear potential ramp can be modelled using the calculation method proposed in our previous work (J. Electroanal. Chem. 818 (2018) 84) provided that the mass transfer function for the species involved in the electrochemical reaction is known in closed form under one-dimensional mass transport conditions. The above approach applies in this short communication to the direct insertion reaction in thin-film planar materials under both anomalous and spatially restricted (confined) diffusion conditions. The Faradaic current is obtained first as an alternating infinite series well suited to formal analysis, and then as an integral formulation well suited to numerical computation. Finally, closed-form expressions of the voltammograms are derived at very low or very high values of the potential sweep rate, respectively. Two anomalous diffusion models taken from the electrochemical literature are investigated and compared, based on their voltammetric responses. The voltammetric peak coordinates obtained from the best model are thoroughly examined, and closed-form approximations are proposed for the voltammetric peak current and potential at very low or very high potential sweep rates. A zone diagram is plotted to illustrate the conditions for observation of those limiting situations. Finally, following a referee's request, an alternative modelling approach is proposed in Appendix, which does not require the use of scientific computation software. This approach involves both the Integral Equation method formalism and numerical inversion of Laplace transform.

The pressure dependence of structure and composition of sputtered AlCrSiTiMoO high entropy thin film

The present study aimed to evaluate the effect of working pressure on the properties of high entropy alloy AlCrSiTiMoO thin film. The layers were deposited by unbalanced DC magnetron sputtering at different working pressures including 1, 4, 8, and 12 mTorr, which is a significant parameter in determining the film properties. The phase formation and crystallinity of AlCrSiTiMoO were evaluated by X-ray diffraction (XRD) method. The morphology and topography of layers were examined by field emission scanning electron microscope (FESEM) and atomic force microscope (AFM), respectively. The morphology of layers with respect to working pressure was almost consistent with the Thornton structure zone diagram although the layer deposited at 1 mTorr owns very smooth surface (Sa = 0.3 nm) with no defect or void within the structure which is very difficult to be placed in any zone presented by the Thornton diagram. The chemical composition of each specimen was measured by energy dispersive spectroscopy (EDS). Based on the results, the amount of oxygen decreased when the pressure increased more than 4 mTorr, while the content of other elements except silicon increased in the coating, which was in good agreement with Simulation of the Metal Transport (SIMTRA). The hardness of deposited films decreased by increasing the pressure which might be related to less energetic neutralized backscattered argon gas impinging on the substrate surface, which was shown by Static and Dynamic Trim for Sequential and Parallel computer (SDTrimSP) code as well as deposition of atoms with lower energy shown by SIMTRA. The hardness and Young’s modulus of the deposited layer at 1 mTorr were equal to 8.9 ± 0.1 GPa and 196 ± 2 GPa, respectively.

Structure Zone Investigation of Multiple Principle Element Alloy Thin Films as Optimization for Nanoindentation Measurements.

Multiple principal element alloys, also often referred to as compositionally complex alloys or high entropy alloys, present extreme challenges to characterize. They show a vast, multidimensional composition space that merits detailed investigation and optimization to identify compositions and to map the composition ranges where useful properties are maintained. Combinatorial thin film material libraries are a cost-effective and efficient way to create directly comparable, controlled composition variations. Characterizing them comes with its own challenges, including the need for high-speed, automated measurements of dozens to hundreds or more compositions to be screened. By selecting an appropriate thin film morphology through predictable control of critical deposition parameters, representative measured values can be obtained with less scatter, i.e., requiring fewer measurement repetitions for each particular composition. In the present study, equiatomic CoCrFeNi was grown by magnetron sputtering in different locations in the structure zone diagram applied to multinary element alloys, followed by microstructural and morphological characterizations. Increasing the energy input to the deposition process by increased temperature and adding high-power impulse magnetron sputtering (HiPIMS) plasma generators led to denser, more homogeneous morphologies with smoother surfaces until recrystallization and grain boundary grooving began. Growth at 300 °C, even without the extra particle energy input of HiPIMS generators, led to consistently repeatable nanoindentation load–displacement curves and the resulting hardness and Young’s modulus values.

New strategies for conformal, superconformal, and ultrasmooth films by low temperature chemical vapor deposition

In the following review, the authors describe how the kinetics of film growth can be controlled in innovative ways to achieve the deposition of conformal, superconformal, area-selective, and ultrasmooth films by low-temperature CVD. Illustrative experimental data and kinetic models are given for the growth of a variety of materials, including transition metals, metal oxides, and metal diborides. Key results are as follows: (i) For precursors that exhibit site blocking on the growth surface, CVD can afford a high degree of conformal coverage on very high aspect ratio features. (ii) The problem of conformal coverage has been solved analytically and presented as a conformal zone diagram. (iii) “Nonconformal” precursor molecules can be made to afford highly conformal films by adding a suitable neutral molecule to enhance surface site blocking. (iv) An inhibitor that adsorbs strongly to the growth material, but not to the substrate surface, can be used to moderate the size distribution of nuclei such that the film is ultrasmooth at coalescence. (v) An inhibitor that binds preferentially to hydroxyl sites on an oxide surface can be used to completely suppress film nucleation and afford area-selective growth. (vi) Superconformal growth, which affords a V-shaped coating and complete fill of a deep trench, can be achieved using one of three approaches, depending on the precursor chemistry. (vii) The science and technology of CVD can further be expanded by the chemical design of new precursors that have a favorable combination of high partial pressure, suitable reactivity at low substrate temperature, and ligand groups that desorb cleanly.

An investigation of homogeneous electrocatalytic mechanism between ferrocene derivatives and l-cysteine/N-Acetyl-l-cysteine

The homogeneous electrocatalytic mechanism with a fast catalytic chemical reaction between a series of ferrocene derivatives and l-cysteine/N-Acetyl-l-cysteine (NAC) is systematically investigated. A comparison of different cyclic voltammetric waveforms is given to illustrate the interaction between kinetic parameter (λ) and excess factor (γ) in kinetic zone diagram via changing the scan rates and substrate/mediator ratio on both glassy carbon (GC) and boron doped diamond (BDD) working electrode experimentally. A split wave phenomenon is observed between ferroceneacetic acid (FAA) and l-cysteine. Also, the waveforms revealed that electron withdrawing groups (EWG) on the substrate hinders the kinetics of the homogeneous electron transfer while those on the mediator facilitates the same process. The homogeneous electrocatalytic order of the studied mediator is as follows: 1,1′-ferrocenedicarboxylic acid (FDA) > FAA > hydroxymethylferrocene (HMF) > 1-hydroxyethylferrocene (HEF) and the corresponding density functional theory (DFT) calculation is applied to support this statement. Furthermore, the second-order rate constant between FAA and l-cysteine is given by the support of numerical simulation (175 (mol m−3)−1 s−1). The present study would facilitate the understanding of homogeneous electrocatalytic process, especially those possessing a fast catalytic chemical step.

Influence of substrate temperature on the morphology and structure of bismuth thin films deposited by magnetron sputtering

The melting point of bismuth is only 271.3 °C which has a great influence on the properties of bismuth itself and the bismuth-contained compounds especially at high temperature. In this paper, the bismuth thin films were prepared using magnetron sputtering method and the influence of deposition temperature on the morphology and structure were investigated over a wide range of substrate temperatures from room temperature to near the melting point. The results showed that 160 °C is a main watershed for the film growth. When the substrate temperature is below 160 °C, the morphology changes a lot from continuous film accumulated mainly by irregular grains to the discontinuous film mainly formed from the isolated polyhedral grains and again to the bimodal grain size distribution of the spherical-polyhedron-shape grains. When the substrate temperature is above 160 °C, the morphology of the bimodal grain size distribution has been maintained except for the changes of the large grain size. The XRD results revealed that the crystallite size hardly changes above 160 °C begin which the bimodal grain size distribution is just formed. The morphology evolution and growth mechanism of bismuth thin films were also studied based on the existing structure zone diagram model and our experimental results.