Search Results (10)

Soft magnetic composite cores were produced by spark plasma sintering (SPS) from Ni₃Fe@ZnFe₂O₄ and NiFeMo@ZnFe₂O₄ pseudo-core-shell powders. In the Fe-Ni alloys@ZnFe₂O₄ pseudo-core-shell composite powders, the core is a large nanocrystalline Permalloy or Supermalloy particle obtained by mechanical alloying, and the shell is a pseudo continuous layer of Zn ferrite particles. The pseudo-core-shell powders have been compacted by SPS at temperatures between 500–700 °C, with a holding time of 0 min. Several techniques were used for the characterisation of the powders and sintered compacts: X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, magnetic hysteresis measurements (DC and AC), and electrical resistivity. The electrical resistivity is stabilised at values of about 7 × 10⁻³ Ω·m for sintering temperatures between 600–700 °C and this value is three orders of magnitude higher than the electrical resistivity of sintered Fe compacts. The best relative initial permeability was obtained for the Supermalloy/ZnFe₂O₄ composite compacts sintered at 600 °C, which decreases linearly for the entire frequency range studied, from around 95 to 50. At a frequency of 2000 Hz, the power losses are smaller than 1.5 W/kg. At a frequency of 10 kHz, the power losses are larger, but they remain at a reduced level. In the case of Supermalloy/ZnFe₂O₄ composite compact SPS-ed at 700 °C, the specific power losses are even lower than 5 W/kg. The power losses’ decomposition proved that intra-particle losses are the main type of losses. Full article

In this paper, we present a novel family of soft sets named “soft ${\omega }_{\delta }$-open sets”. We find that this class constitutes a soft topology that lies strictly between the soft topologies of soft $\delta$-open sets and soft ${\omega }^0$-open sets. Also, we introduce certain sufficient conditions for the equivalence between this new soft topology and several existing soft topologies. Moreover, we verify several relationships that contain soft covering properties, such as soft compactness and soft Lindelofness, which are related to this new soft topology. Furthermore, in terms of the soft interior operator in certain soft topologies, we define four classes of soft sets. Via them, we obtain new decomposition theorems for soft $\delta$-openness and soft $\theta$-openness, and we characterize the soft topological spaces that have the soft “semi-regularization property”. In addition, via soft ${\omega }_{\delta }$-open sets, we introduce and investigate a new class of soft functions named “soft ${\omega }_{\delta }$-continuous functions”. Finally, we look into the connections between the newly proposed soft concepts and their counterparts in classical topological spaces. Full article

The concepts of soft faint continuity as a weaker form of soft weak continuity and soft faint ${\theta }_{\omega }$-continuity as a weaker form of soft weak ${\theta }_{\omega }$-continuity are introduced. Numerous characterizations of them are given. We further demonstrate that, under soft restrictions, they are retained. Moreover, we show that a soft function is soft faintly continuous (respectively, soft faintly ${\theta }_{\omega }$-continuous) if its soft graph function is soft faintly continuous (respectively, soft faintly ${\theta }_{\omega }$-continuous). In addition, we show that a soft function with a soft almost regular (respectively, soft extremally disconnected) co-domain is soft faintly continuous iff it is soft almost continuous (respectively, soft $\delta$-continuous). Furthermore, we show that soft faintly continuous surjective functions are soft set-connected functions, and as a corollary, we demonstrate how soft faintly continuous functions sustain soft connectivity. Finally, we studied the symmetry between our new notions and their topological counterparts. Full article

Soft $\omega$-$\theta$-continuity and soft weak-${\theta }_{\omega }$-continuity as two new concepts of continuity are presented and investigated. The investigation of the links between these forms of soft mappings and their general topological relatives is given. With the help of examples, it is investigated that soft $\omega$-$\theta$-continuity lies strictly between soft $\theta$-continuity and soft weak-continuity, while soft weak-${\theta }_{\omega }$-continuity lies strictly between soft continuity (i.e., soft ${\theta }_{\omega }$-continuity) and soft weak-continuity. A number of conditions for the equivalence between soft $\omega$-$\theta$-continuity and soft weak continuity (i.e., soft $\omega$-$\theta$-continuity and soft $\theta$-continuity, soft weak-${\theta }_{\omega }$-continuity and soft weak-continuity, soft weak-${\theta }_{\omega }$-continuity and soft continuity) are obtained. Additionally, soft $\theta$-closure and soft ${\theta }_{\omega }$-closure operators are used to characterize our new types of soft mappings. Full article

In this paper, we present a soft and moisturizing film electrode based on bacterial cellulose and Ag/AgCl conductive cloth as a potential replacement for gel electrode patches in electroencephalogram (EEG) recording. The electrode materials are entirely flexible, and the bacterial cellulose membrane facilitates convenient adherence to the skin. EEG signals are transmitted from the skin to the bacterial cellulose first and then transferred to the Ag/AgCl conductive cloth connected to the amplifier. The water in the bacterial cellulose moisturizes the skin continuously, reducing the contact impedance to less than 10 kΩ, which is lower than commercial gel electrode patches. The contact impedance and equivalent circuits indicate that the bacterial cellulose electrode effectively reduces skin impedance. Moreover, the bacterial cellulose electrode exhibits lower noise than the gel electrode patch. The bacterial cellulose electrode has demonstrated success in collecting α rhythms. When recording EEG signals, the bacterial cellulose electrode and gel electrode have an average coherence of 0.86, indicating that they have similar performance across different EEG bands. Compared with current mainstream conductive rubber dry electrodes, gel electrodes, and conductive cloth electrodes, the bacterial cellulose electrode has obvious advantages in terms of contact impedance. The bacterial cellulose electrode does not cause skin discomfort after long-term recording, making it more suitable for applications with strict requirements for skin affinity than gel electrode patches. Full article

The notions of continuity and separation axioms have significance in topological spaces. As a result, there has been a substantial amount of research on continuity and separation axioms, leading to the creation of several modifications of these axioms. In this paper, the concepts of soft slight $\omega$-continuity, soft ultra-Hausdorff, soft ultra-regular, and soft ultra-normal are initiated and investigated. Their characterizations and main features are determined. Also, the links between them and some other relevant concepts are obtained with the help of examples. Moreover, the equivalency between these notions and other related concepts is given under some necessary conditions. In addition, the inverse image of the introduced types of soft separation axioms under soft slight continuity and soft slight $\omega$-continuity is studied, and their reciprocal relationships with respect to their parametric topological spaces are investigated. Full article

A novel piezoelectric generator based on soft piezoelectric film consisting of a polyimide (PI) sheet and lead zirconate titanate (PZT) is proposed to generate electric energy under the operating conditions of low-frequency and small-amplitude vibration. The theoretical model and working principle of the piezoelectric generator are discussed in detail. Using ANSYS software, a finite element analysis of the static and modal characteristics of the piezoelectric generator is carried out. Further, the output of the prepared piezoelectric generator is investigated by a home-made experimental platform. Results show that the transient excitation voltage of the generator increases with the increase in load resistance, and the continuous excitation voltage increases first and then remains almost stable. The maximum continuous power produced by the piezoelectric generator is about 4.82 mW. Furthermore, the continuous excitation voltage and power are in accordance with the simulation values when the load resistances are 20 kΩ and 25 kΩ, respectively. Full article

In this paper, we define a soft generalized $\omega$-closed set, which is a generalization of both the soft $\omega$-closed set and the soft generalized closed set. We show that the classes of generalized closed sets and generalized $\omega$-closed sets coincide in soft anti-locally countable soft topological spaces. Additionally, in soft locally countable soft topological spaces, we show that every soft set is a soft generalized $\omega$-closed set. Furthermore, we prove that the classes of soft generalized closed sets and soft generalized $\omega$-closed sets coincide in the soft topological space $(X,{\tau }_{\omega },A)$. In addition to these, we determine the behavior of soft generalized $\omega$-closed sets relative to soft unions, soft intersections, soft subspaces, and generated soft topologies. Furthermore, we investigate soft images and soft inverse images of soft generalized closed sets and soft generalized $\omega$-closed sets under soft continuous, soft closed soft transformations. Finally, we continue the study of soft $T_{1/2}$ spaces, in which we obtain two characterizations of these soft spaces, and investigate their behavior with respect to soft subspaces, soft transformations, and generated soft topologies. Full article

We define soft ${\omega }_p$-openness as a strong form of soft pre-openness. We prove that the class of soft ${\omega }_p$-open sets is closed under soft union and do not form a soft topology, in general. We prove that soft ${\omega }_p$-open sets which are countable are soft open sets, and we prove that soft pre-open sets which are soft $\omega$-open sets are soft ${\omega }_p$-open sets. In addition, we give a decomposition of soft ${\omega }_p$-open sets in terms of soft open sets and soft $\omega$-dense sets. Moreover, we study the correspondence between the soft topology soft ${\omega }_p$-open sets in a soft topological space and its generated topological spaces, and vice versa. In addition to these, we define soft ${\omega }_p$-continuous functions as a new class of soft mappings which lies strictly between the classes of soft continuous functions and soft pre-continuous functions. We introduce several characterizations for soft pre-continuity and soft ${\omega }_p$-continuity. Finally, we study several relationships related to soft ${\omega }_p$-continuity. Full article

To solve the soft sensor modeling (SSMI) problem in a nonlinear chemical process with dynamic time variation and multi-rate data, this paper proposes a dynamic SSMI method based on an autoregressive moving average (ARMA) model of weighted process data with discount (DSSMI-AMWPDD) and optimization methods. For the sustained influence of auxiliary variable data on the dominant variables, the ARMA model structure is adopted. To reduce the complexity of the model, the dynamic weighting model is combined with the ARMA model. To address the weights of auxiliary variable data with different sampling frequencies, a calculation method for AMWPDD is proposed using assumptions that are suitable for most sequential chemical processes. The proposed method can obtain a discount factor value (DFV) of auxiliary variable data, realizing the dynamic fusion of chemical process data. Particle swarm optimization (PSO) is employed to optimize the soft sensor model parameters. To address the poor convergence problem of PSO, ω-dynamic PSO (ωDPSO) is used to improve the PSO convergence via the dynamic fluctuation of the inertia weight. A continuous stirred tank reactor (CSTR) simulation experiment was performed. The results show that the proposed DSSMI-AMWPDD method can effectively improve the SSM prediction accuracy for a nonlinear time-varying chemical process. The AMWPDD proposed in this paper can reflect the dynamic change of chemical process and improve the accuracy of SSM data prediction. The ω dynamic PSO method proposed in this paper has faster convergence speed and higher convergence accuracy, thus, these models correlate with the concept of symmetry. Full article