Use Of Synthesis Methods Research Articles

The use of synthesis methods in position optimisation and selection of tuned mass damper (TMD) parameters for systems with many degrees of freedom

The use of synthesis methods in position optimisation and selection of tuned mass damper (TMD) parameters for systems with many degrees of freedom

The first progress of plasma-based transition metal dichalcogenide synthesis: a stable 1T phase and promising applications.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted attention as polymorphs depending on their phases (1T and 2H) when applying typical synthesis methods. The 2H phase is generally synthesised through chemical vapour deposition (CVD) on a wafer-scale at high temperatures, and many synthesis methods have been reported owing to their thermodynamic stability and semiconductor properties. By contrast, although the 1T phase is meta-stable with an octahedral coordination, thereby limiting the use of synthesis methods, the recent structural advantage in terms of the hydrogen evolution reaction (HER) has been emphasised. Despite this demand, no large-area thin-film synthesis method for 1T-TMDs has been developed. Among several strategies of synthesizing metallic-phase (1T) TMDs, chemical exfoliation (alkali metal intercalation) is a major strategy and others have been used for electron-beam irradiation, laser irradiation, defects, plasma hot electron transfer, and mechanical strain. Therefore, we suggest an innovative synthesis method using plasma-enhanced CVD (PECVD) for both the 1T and 2H phases of TMDs (MoS2 and WS2). Because ions and radicals are accelerated to the substrate within the sheath region, a high-temperature source is not needed for vapour ionisation, and thus the process temperature can be significantly lowered (150 °C). Moreover, a 4-inch wafer-scale of a thin film is an advantage and can be synthesised on arbitrary substrates (SiO2/Si wafer, glassy carbon electrode, Teflon, and polyimide). Furthermore, the PECVD method was applied to TMD-graphene heterostructure films with a graphene-transferred substrate, and for the first time, sequential metal seed layer depositions of W (1 nm) and Mo (1 nm) were sulfurized to MoS2-WS2 vertical heterostructures with Ar + H2S plasma. We considered the prospects and challenges of the new PECVD method in the development of practical applications in next-generation integrated electronics, HER catalysts, and flexible biosensors.

Perceptual Evaluation of Synthesized Sound Effects

Sound synthesis is the process of generating artificial sounds through some form of simulation or modelling. This article aims to identify which sound synthesis methods achieve the goal of producing a believable audio sample that may replace a recorded sound sample. A perceptual evaluation experiment of five different sound synthesis techniques was undertaken. Additive synthesis, statistical modelling synthesis with two different feature sets, physically inspired synthesis, concatenative synthesis, and sinusoidal modelling synthesis were all compared. Evaluation using eight different sound class stimuli and 66 different samples was undertaken. The additive synthesizer is the only synthesis method not considered significantly different from the reference sample across all sounds classes. The results demonstrate that sound synthesis can be considered as realistic as a recorded sample and makes recommendations for use of synthesis methods, given different sound class contexts.

Green synthesis of reduced graphene oxide using ball milling

Today, finding superior methods for synthesis of graphene oxide (GO) and reduced graphene oxide (rGO) from commercial graphite, is still a challenge. The global industry requires the use of synthesis methods that are price-competitive and also use processes that are environmentally compatible. GO is a substrate used for several chemical transformations, including its reduction to related materials, such as rGO and graphene. The rGO has been used recently to increase catalytic activity in the o-nitroaniline reduction to NaBH4 and Raman activity in test molecules as p-aminothiophenol [1]. Other authors showed that the rGO in combination with carbon nanotubes has the properties of supercapacitors [2]. Mao et al. [3] obtained a gas sensor type field defect transistor of high sensitivity at low concentrations, using sheets of rGO. On the other hand, rGO linked with Cu2O nanocrystals is capable of removing dye pollution from wastewater [4].

The Method for Determining the Vibration-Damping Elements for the Mechanical System to Obtain the Desired Amplitude Value

The paper presents the use of synthesis methods to determine the parameters of passive vibration reduction in mechanical systems. Passive vibration reduction in a system is enabled by units called dampers whose values are determined on the basis of the method formulated and formalized by the authors. The essence of the method are, established at the beginning of a task, dynamic characteristics in the form of the resonance and anti-resonance frequencies, and amplitudes of displacement, velocity or acceleration of vibration.

Hierarchical network meta‐analysis models to address sparsity of events and differing treatment classifications with regard to adverse outcomes

Meta-analysis for adverse events resulting from medical interventions has many challenges, in part due to small numbers of such events within primary studies. Furthermore, variability in drug dose, potential differences between drugs within the same pharmaceutical class and multiple indications for a specific treatment can all add to the complexity of the evidence base. This paper explores the use of synthesis methods, incorporating mixed treatment comparisons, to estimate the risk of adverse events for a medical intervention, while acknowledging and modelling the complexity of the structure of the evidence base. The motivating example was the effect on malignancy of three anti-tumour necrosis factor (anti-TNF) drugs (etanercept, adalimumab and infliximab) indicated to treat rheumatoid arthritis. Using data derived from 13 primary studies, a series of meta-analysis models of increasing complexity were applied. Models ranged from a straightforward comparison of anti-TNF against non-anti-TNF controls, to more complex models in which a treatment was defined by individual drug and its dose. Hierarchical models to allow 'borrowing strength' across treatment classes and dose levels, and models involving constraints on the impact of dose level, are described. These models provide a flexible approach to estimating sparse, often adverse, outcomes associated with interventions. Each model makes its own set of assumptions, and approaches to assessing goodness of fit of the various models will usually be extremely limited in their effectiveness, due to the sparse nature of the data. Both methodological and clinical considerations are required to fit realistically complex models in this area and to evaluate their appropriateness.