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In this paper, we investigated several new fixed points theorems for multivalued mappings in the framework b -metric spaces. We first generalized S -iterative schemes for multivalued mappings to above spaces by means of a convex structure and then we developed the existence of fixed points and approximate endpoints of the multivalued contraction mappings using iteration techniques. Furthermore, we introduced the modified S -iteration process for approximating a common endpoint of a multivalued α s -nonexpansive mapping and a multivalued mapping satisfying conditon (E ′ ) . We also showed that this new iteration process converges faster than the S -iteration process in the sense of Berinde. Some convergence results for this iterative procedure to a common endpoint under some certain additional hypotheses were proved. As an application, we applied the S -iteration process in finding the solution to a class of nonlinear quadratic integral equations. In this paper, we investigated several new fixed points theorems for multivalued mappings in the framework -metric spaces. We first generalized -iterative schemes for multivalued mappings to above spaces by means of a convex structure and then we developed the existence of fixed points and approximate endpoints of the multivalued contraction mappings using iteration techniques. Furthermore, we introduced the modified -iteration process for approximating a common endpoint of a multivalued -nonexpansive mapping and a multivalued mapping satisfying conditon . We also showed that this new iteration process converges faster than the -iteration process in the sense of Berinde. Some convergence results for this iterative procedure to a common endpoint under some certain additional hypotheses were proved. As an application, we applied the -iteration process in finding the solution to a class of nonlinear quadratic integral equations. [ABSTRACT FROM AUTHOR]

[Objectives] For star type multistage high-pressure reciprocating compressor, the change of cylinder pressure under different working conditions has not been mastered accurately, and the related dynamic analysis can only be calculated on the basis of theoretical value. Measurement of the actual cylinder pressure of the compressor is helpful to improve the accuracy of the dynamic analysis of the star type compressor.[Methods] In this paper,on the premise of not damaging the cylinder structure,each cylinder pressure under different working conditions is successfully measured by the valve stem drilling method,and the vibration acceleration of the cylinder head and base is tested. and the self-balance performance of compressor has good for second-order inertia force is obtained by theoretical analysis. The crank connecting rod mechanism is simplified to establish ADAMS dynamic model,and the parameterized design method is used to obtain the optimum balance weight. Under the working condition of 25 MPa exhaust pressure,the measured gas force is converted into a force applied to the piston and then loaded on the piston centroid,and then the force of the main bearing is obtained.[Results] The results show that the stress of the main bearing is the first-order and three-order inertia forces,the change of the compressor working condition mainly affects the three-stage and four-stage cylinder pressures,and the vibration of the first cylinder is relatively severe.[Conclusions] The crank connecting rod mechanism of the compressor has good self-balance. The test results provide reference for mastering the characteristics of the cylinder pressure of the star type compressor and analyzing the vibration characteristics of the compressor.

[Objectives] Compared with other types of air compressor, reciprocating compressors can obtain compressed air with a higher pressure, exerting more stress on the crank connecting rod mechanism. [Methods] This paper analyzes the inertia force and torque characteristics of the three structural forms of the star-type reciprocating air compressor. It then concludes that the air compressor has a good self-balance ability of inertial force while also reducing inertial torque to a certain extent at the same time. A virtual prototype of a crank connecting rod mechanism is built. The derivation of the force on the piston is acquired in order to construct a SPLINE curve, which is loaded on the centroid of the piston. With a flexible crankshaft, the contact force model of the IMPACT function is added between the crank pin and connecting rod. [Results] The dynamic simulation results show that the air compressor can self-balance second-order inertial force. Clearance will decrease the vibration of the air compressor to a certain extent, but will greatly broaden the excitation frequency band. [Conclusions] The findings of this paper can provide valuable references for the design of air compressors.

In light of the predicament concerning the small gain and narrow frequency range of miniature antennas, this paper employs the implementation of a fractal repeating array structure and a double-layer folding antenna structure. Through these measures, the miniature antenna is endowed with a high gain and an expansive frequency range, all within its diminutive size. The paper presents an exquisite and high-gain flexible multi-band antenna, utilizing a dielectric substrate composed of the flexible material polyimide, with a thickness of merely 0.1 mm. The implementation of this flexible material bestows a feathery mass of merely 4 mg upon the antenna, enabling it to seamlessly conform to various shapes. This makes it particularly well-suited for employment within miniature wireless transmission systems and compact mobile communication devices. In an endeavor to enhance impedance matching and radiation characteristics, the Minkowski fractal structure is ingeniously incorporated as the repeating array element. This repeating array structure assumes a pivotal role and, when combined with the double-layer folding antenna structure, achieves the objective of miniaturization. Remarkably, the antenna's dimensions measure a mere 0.04 λ0 × 0.026 λ0 (λ0 @ 2.4 GHz). The proposed antenna boasts a remarkably diminutive volume of merely 5 × 3 × 0.1 mm3, with the measured and simulated results exhibiting a striking concurrence. Both sets of results demonstrate resonance across multiple frequencies, namely, 2.4 GHz, 5.2 GHz and 5.8 GHz. Furthermore, within the effective frequency range, the antenna attains a maximum gain of 1.65 dBi and 4.37 dBi, respectively. [ABSTRACT FROM AUTHOR]

Thickness nonuniformity is a bottleneck in the micro electroforming process of micro-metal devices. In this paper, a new method of fabricating a layered auxiliary cathode is proposed to improve the thickness uniformity of a micro-electroforming layer. In order to analyze the general applicability of the proposed method, four basic microstructures, namely circular, square, regular triangular, and regular hexagonal were used to study the effect of a layered auxiliary cathode on thickness uniformity through simulation and experimentation. The simulation results showed that with the help of the proposed auxiliary cathode, the thickness nonuniformity of four microstructures should decrease due to the reduced edge effect of the current density. The experimental results showed that the thickness uniformity of four microstructures fabricated via the proposed method was improved by 190.63%, 116.74%, 80.43%, and 164.30% compared to that fabricated via the traditional method, respectively. Meanwhile, the micro-gear was fabricated and the nonuniformity was reduced by 101.15% using the proposed method. [ABSTRACT FROM AUTHOR]

The thickness nonuniformity of an electroformed layer is a bottleneck problem for electroformed micro metal devices. In this paper, a new fabrication method is proposed to improve the thickness uniformity of micro gear, which is the key element of various microdevices. The effect of the thickness of the photoresist on the uniformity was studied by simulation analysis, which showed that as the thickness of the photoresist increased, the thickness nonuniformity of the electroformed gear should decrease due to the reduced edge effect of the current density. Differently from the traditional method performed by one-step front lithography and electroforming, multi-step, self-aligned lithography and electroforming are used to fabricate micro gear structures in proposed method, which intermittently keeps the thickness of photoresist from decreasing during processes of alternate lithography and electroforming. The experimental results show that the thickness uniformity of micro gear fabricated by the proposed method was improved by 45.7% compared with that fabricated by the traditional method. Meanwhile, the roughness of the middle region of the gear structure was reduced by 17.4%. [ABSTRACT FROM AUTHOR]

Recent progress in the fabrication of controlled structures and advanced materials has improved battery performance in terms of specific capacity, rate capability, and cycling stability. However, interfacial problems such as increased resistance and contact instability between the electrodes and solid/liquid electrolytes still put pressure on the controllable formation of structures and the improvement of performance as well as safety. Here, we first briefly introduce the deposition techniques in terms of working mechanism and experimental process, then illustrate the associated advantages/disadvantages of the surface engineering methods based on deposition techniques (physical vapor deposition and chemical reaction deposition) to the provision of reference for researchers selecting the appropriate approach. Second, we exemplify the Si/LiCoO2/LiPON/Li to demonstrate the main progress made in lithium-ion batteries, elaborating on the efforts in engineering the reactive surface utilizing the deposition techniques. Finally, general conclusions and prospects for future advanced thin film deposition techniques in the field of lithium-ion batteries are presented. [ABSTRACT FROM AUTHOR]

In this paper, we present a series of fixed point results for Mann's iteration scheme in the framework of G b -metric spaces. First, we introduce the concept of convex G b -metric space by means of a convex structure and Mann's iteration algorithm is extended to this space. Furthermore, using Mann's iteration scheme, we prove some fixed point results for several mappings satisfying various suitable conditions on complete convex G b -metric spaces. Some examples supporting our main results are also presented. We also discuss the well-posedness of the fixed point problems and the P property for given mappings. Moreover, as an application, we apply our main result to prove the existence of the solutions to integral equations. [ABSTRACT FROM AUTHOR]

Multivalent secondary batteries (MSBs) have attracted great attention in view of their rich resources, low cost, and high safety. However, its development and application are still plagued by electrode materials. With their renewable and highly adjustable structures, organic electrode materials (OEMs) have several advantages over traditional inorganic electrode materials (IEMs), which has become the current research hotspot of electrode materials for MSBs. In this review, we present the recent developments in OEMs used for secondary batteries, including carbonyl compounds, imine compounds, conductive polymers, covalent organic frameworks, organic cyanides, organosulfur polymers and so on. An overview of the structural characteristics, energy storage mechanism, and electrochemical performance of OEMs in MSBs is given. Furthermore, to reveal the reasons for the high performance of the preponderant organic electrode materials, the relationships between material structures, electrolyte system, and battery properties are discussed in detail. Finally, we hope that this review could provide a fundamental guide to developing and designing high‐performance MSBs in the future. [ABSTRACT FROM AUTHOR]

In this paper, the concept of convex rectangular b − metric spaces is introduced as a generalization of both convex metric spaces and rectangular b − metric spaces. The purpose of this study is to indicate a way of generalizing Mann's iteration algorithm and a series of fixed point results in rectangular b − metric spaces. Furthermore, certain examples are given to support the results. We also study well posedness of fixed point problems of some mappings in convex rectangular b − metric spaces, and an application to the dynamic programming is entrusted to manifest the viability of the obtained results. Our results extend comparable results in the existing literature. [ABSTRACT FROM AUTHOR]

Resistive random access memory (RRAM) based on ultrathin 2D materials is considered to be a very feasible solution for future data storage and neuromorphic computing technologies. However, controllability and stability are the problems that need to be solved for practical applications. Here, by introducing a damage‐less ion implantation technology using ultralow‐energy plasma, the transport mechanisms of space charge limited current and Schottky emission are successfully realized and controlled in RRAM based on 2D Bi2Se3 nanosheets. The memristors exhibit stable resistive switching behavior with a high resistive switching ratio (>104), excellent cycling endurances (300 cycles), and great retention performance (>104 s). The reliability and controllability of Bi2Se3 memory endowed by oxygen plasma injection demonstrate the great potential of this ultralow‐energy ion implantation technology in the application of 2D RRAM. [ABSTRACT FROM AUTHOR]

To prepare a hierarchical micro-nano structure FeF3·0.33H2O simply and economically, a one-pot method with dual surfactants was used. Scanning electron microscopy and a Fourier transformation infrared spectrometer revealed that polyvinyl pyrrolidone (PVP) regulates the morphology of the material, while cetyltrimethylammonium bromide (CTAB) can reshape FF@PVP, it can not only remove PVP at room temperature, but also obtain a hierarchical micro-nano structure. The electrochemical results show that the hierarchical micro-nano structure FF(1.5CTAB 0.5PVP) has the best electrochemical performance. It maintained a high specific capacity of 109.4 mAh g−1 after 100 cycles at 1 C. In particular, under the ultra-high rate discharge of 20 C, the ultra-high specific discharge capacity of 66.4 mAh g−1 was reached. The FF(1.5CTAB 0.5PVP)'s excellent electrochemical performance is mainly due to a large contact area between the electrolyte and active materials. [ABSTRACT FROM AUTHOR]

In this paper, we prove the existence and uniqueness of fixed points for F -contractions in complete Branciari b -metric spaces. Furthermore, an example for supporting the related result is shown. We also present the concept of the weak well-posedness of the fixed-point problem of the mapping T and discuss the weak well-posedness of the fixed-point problem of an F -contraction in complete Branciari b -metric spaces. Besides, we investigate the problem of common fixed points for F -contractions in above spaces. As an application, we apply our main results to solving the existence and uniqueness of solutions for a class of the integral equation and the dynamic programming problem, respectively. [ABSTRACT FROM AUTHOR]

An improved contact collision model for the impact analysis of a slider–crank mechanism with revolute clearance joints is presented and discussed in this paper. Clearances in revolute joints are inevitable due to wear, machining tolerance, and local deformations. In view of the energy loss and the stiffness changes during collision, which modifies the coulomb friction force, an improved contact collision force model is established. The influence of clearance size, speed, and friction on the acceleration of slider is analyzed, and the simulation results are compared with the experimental data. The results demonstrate that the parameters of clearance joints have obvious effects on dynamic characteristics, and the improved model can accurately describe the dynamic characteristics of joints with clearance. [ABSTRACT FROM AUTHOR]

Wettability is an important property of solid surfaces and is widely used in many industries. In this work, seven silicon microstructure surfaces were made by plasma immersion ion implantation (PIII) technology. The experimental contact angles and theoretical contact angles of various surfaces were compared, which indicated that the classical theory had great limitations in predicting the static contact angles of complex structures. A parameterized microstructure surface was established by computational fluid dynamics (CFD) with a volume-of-fluid (VOF) model to analyze the reasons for the differences between experimental and theoretical contact angles. Comparing the results of experiments and simulations, it was found that the VOF model can simulate the contact angle of these surfaces very well. The geometrical models of the different microstructures were simplified, and waveforms of the surfaces were obtained. [ABSTRACT FROM AUTHOR]

Our paper is devoted to indicating a way of generalizing Mann's iteration algorithm and a series of fixed point results in the framework of b-metric spaces. First, the concept of a convex b-metric space by means of a convex structure is introduced and Mann's iteration algorithm is extended to this space. Next, by the help of Mann's iteration scheme, strong convergence theorems for two types of contraction mappings in convex b-metric spaces are obtained. Some examples supporting our main results are also presented. Moreover, the problem of the T-stability of Mann's iteration procedure for the above mappings in complete convex b-metric spaces is considered. As an application, we apply our main result to approximating the solution of the Fredholm linear integral equation. [ABSTRACT FROM AUTHOR]

Semiconductor technology is currently impaired by the surface dangling bond of materials, which introduces scattering and interface traps. 2D materials, especially transition metal dichalcogenides (TMDs) with different main groups, have settled this issue by utilizing unique atomically smooth surfaces and van der Waals (vdW) structures. Over the past few decades, many processes for exploring new materials, manipulating physical properties, and synthesizing single crystals have been developed. Among these 2D materials, group IVB TMDs are distinguished for their splendid physical properties, including ultrahigh mobility, charge density wave, superconducting transitions, etc. Here, the recent advances in group IVB TMDs are reviewed, which offer easy access to next generation nano‐, opto‐, thermal‐electronic, energy storage and conversion applications. Both the advantages and challenges of these studies are summarized to further clarify existing problems. 2D group IVB transition metal dichalcogenides (TMDs) are distinguished for their splendid properties and potential applications in next generation nano‐, opto‐, thermal‐electronic, energy storage and conversion. This article reviews the recent studies on their properties correlating to crystal and electronic structures, various applications, and synthesis methods. Both the advantages and challenges of these materials are summarized for further development. [ABSTRACT FROM AUTHOR]

This paper presents a 96-well microfabricated assay to study three-dimensional (3D) invasion of tumor cells. A 3D cluster of tumor cells was first generated within each well by seeding cells onto a micro-patterned surface consisting of a central fibronectin-coated area that promotes cellular attachment, surrounded by a poly ethylene glycol (PEG) coated area that is resistant to cellular attachment. Following the formation of the 3D cell clusters, a 3D collagen extracellular matrix was formed in each well by thermal-triggered gelation. Invasion of the tumor cells into the extracellular matrix was subsequently initiated and monitored. Two modes of cellular infiltration were observed: A549 cells invaded into the extracellular matrix following the surfaces previously coated with PEG molecules in a pseudo-2D manner, while H1299 cells invaded into the extracellular matrix in a truly 3D manner including multiple directions. Based on the processing of 2D microscopic images, a key parameter, namely, equivalent invasion distance (the area of invaded cells divided by the circumference of the initial cell cluster) was obtained to quantify migration capabilities of these two cell types. These results validate the feasibility of the proposed platform, which may function as a high-throughput 3D cellular invasion assay. [ABSTRACT FROM AUTHOR]