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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]

Video anomaly detection is an important task for public security in the multimedia field. It aims to distinguish events that deviate from normal patterns. As important semantic representation, the textual information can effectively perceive different contents for anomaly detection. However, most existing methods primarily rely on visual modality, with limited incorporation of textual modality in anomaly detection. In this paper, a cross-modality integration framework (CIForAD) is proposed for anomaly detection, which combines both textual and visual modalities for prediction, perception and discrimination. Firstly, a feature fusion prediction (FUP) module is designed to predict the target regions by fusing the visual features and textual features for prompting, which can amplify the discriminative distance. Then an image-text semantic perception (ISP) module is developed to judge semantic consistency by associating the fine-grained visual features with textual features, where a strategy of local training and global inference is introduced to perceive local details and global semantic correlation. Finally, a self-supervised time attention discrimination (TAD) module is built to explore the inter-frame relation and further distinguish abnormal sequences from normal sequences. Extensive experiments on the three challenging benchmarks indicate that our CIForAD obtains state-of-the-art anomaly detection performance. • Cross-modality integration framework (CIForAD) for unsupervised anomaly detection. • Prompts for frame prediction by fusing visual and textual features. • Semantic correlation maintained by image-text semantic perception module. • Time attention strategy on inter-frame relation for distinguishing time differences. • Extensive evaluations show outstanding anomaly detection performance. [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]

The hallmark of ovarian cancer is its high mortality rate attributed to the existence of cancer stem cells (CSCs) subpopulations which result in therapy recurrence and metastasis. A series of C-29-substituted and/or different A/B ring of celastrol derivatives were synthesized and displayed potential inhibition against ovarian cancer cells SKOV3, A2780 and OVCAR3. Among them, compound 6c exhibited the most potent anti-proliferative activity and selectivity, gave superior anti-CSC effects through inhibition of the sphere formation and downregulation of the percentage of CD44+CD24− and ALDH+ cells. Further mechanism research demonstrated that compound 6c could attenuate the expression of STAT3 and p-STAT3. The results suggested that the inhibition of celastrol derivative 6c on ovarian cancer cells may be related to resistance to cancer stem-like characters and regulation of STAT3 pathway. [Display omitted] • A series of celastrol derivatives were synthesized and evaluated their anti-ovarian cancer effects. • Compound 6c was the promising anti-CSC leading compound. • Compound 6c inhibited the sphere formation and decreased the percentage of CD44+CD24− and ALDH+ cells. • Compound 6c could downregulate the expression of STAT3 and p-STAT3 that contributed to its CSC inhibition. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a novel opto-mechanical uncooled infrared detector that has successfully been fabricated. The detector is composed of a bi-material micro-cantilever array released from the Si substrate, whose reflector retains its shape even with changes in temperature. In comparison with the generally used sacrificial layer cantilever, the loss of incident IR energy caused by the reflection from and absorption by the silicon substrate is eliminated in this substrate-free structure. Moreover, the freestanding structure of the detector makes it easy to fabricate. The revised reflector in this structure has no distortion during its activity that keeps the sensitivity of the detector from being passivated. We present an infrared (IR) image of a person’s hand to demonstrate the ability of the structure to create images. The performance test showed that the noise-equivalent temperature difference of the imaging system can reach about 175mK. [Copyright &y& Elsevier]

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]

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]

• Propose Cycle Reinforce Hierarchical Model for recognition tasks. • Design hierarchical structure composed of several hidden layers for features evolution. • Adopt groups of fuzzy subsystems with fuzzy rules ensures the diversity of features. • Introduce cycle mechanism for transferring refined coefficients. • Measure innovative strategies by the perspective of contribution rate. Neuro-fuzzy models have been applied in various domains, in which the issue of long time-consumption for optimizing parameters and less innovation in fuzzy method for feature extraction remains to be solved. Here, we present a novel cycle reinforce hierarchical model (CRHM) for effective and efficient recognition. The innovative strategies of CRHM consist of the hierarchical structure, the groups of fuzzy subsystems and the cycle mechanism. The hierarchical structure is innovatively built to extract features and transform the low-level features into advanced ones semantically, in which we adopt the groups of fuzzy subsystems as feature extraction units in each hidden layer, which ensures the diversity of features, avoids the fuzzy rules explosion, and reduces the time for clustering. The cycle mechanism is first proposed to connect the hierarchical structure and the output layer directly, transferring the tuned parameters again and again, to reinforce features gradually. To demonstrate the performance of CRHM, we have conducted extensive comparison with several state-of-the-art algorithms on benchmark 1D and 2D datasets. The experimental results show that the recognition rate of CRHM is higher than convolutional neural network (CNN), while the training time is only 5% of CNN's, which confirms that our approach provides a novel model for recognition, which can simultaneously improve the effectiveness and efficiency without the need of advanced equipment. In addition, the analysis results about the contribution of the core strategies to CRHM performance indicates that the contribution of the hierarchical structure is greater than that of the groups of fuzzy subsystems, which is superior than that of the cycle mechanism. [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]

Highlights: [•] ZnO films have been grown on (0001) sapphire substrates by variable electric field-assisted ALD technique. [•] XRD and XPS spectra demonstrate that not only the crystal orientation, but also the oxygen vacancy defect could be modulated by changing the electric field directions of the chamber during precursor pulses. [•] The results of HRTEM show the obtained ZnO thin films have a high crystal quality. [•] It is supposed that substrate electric polarity would expect to modulate the structures and properties of ZnO films. [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]

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]

Honeycomb structure is extraordinarily effective to trap light, and the efficiency of solar cell with this texture is as high as 24.4 %. In this paper, plasma immersion ion implantation and acid etching are applied to texture multi-crystalline silicon. Surface reflectivity and surface morphology are investigated by UV-Vis-NIR spectrophotometer and field emission scanning electron microscopy, respectively. We found that random nano-honeycomb structures have been formed on silicon surface. The weighted average reflectance is 7.68 % from 300 to 1,100 nm wavelength region. We obtained honeycomb-textured solar cells following standard fabrication protocol. These solar cells show obvious better performance in short circuit current density (>5.4 %) and efficiency (~0.8 % absolute) compared with acid-textured cell, while other performance parameters, such as open circuit voltage and fill factor, are not deteriorated. [ABSTRACT FROM AUTHOR]

In this paper we present a novel method of regulation to obtain graphene layers with homogeneous thickness by means of helium plasma implantation. The obtained graphene layers show neither large deep pits nor loss of lateral dimension. The etching rate can be precisely controlled (one to six atomic layers min−1 or higher) and it remains consistent regardless of the thickness of the multilayer graphene. This approach is compatible with traditional complementary metal–oxide–semiconductor fabrication technologies and has great potential to modulate the performance of graphene for device applications. [ABSTRACT FROM AUTHOR]

A black silicon on emitter (BSOE) solar cell, with a uniform depletion region, was investigated by its internal quantum efficiency (IQE) and by scanning electron microscopy using an electron beam-induced current. We establish a three-dimensional energy band diagram of a non-uniform depletion region to illustrate the shunt effect by introducing a lateral electric field into the black silicon solar cell. The IQE spectral response at 450nm is enhanced by ∼31%. The conversion efficiency is improved by 0.8% abs compared with a black silicon solar cell. [Copyright &y& Elsevier]

Abstract: An optimized textured structure is a key for high efficiency multi-crystalline silicon solar cell. In this work, black silicon wafers with various structures have been successfully produced by plasma immersion ion implantation. The surface morphology, reflectance and internal quantum efficiency have been investigated by atomic force microscope, spectrophotometer and quantum efficiency measurement system, respectively. Results show that nanohillocks with average height of 150–600nm have been generated on black silicon surfaces by different texturing conditions, and the reflectance over the wavelength from 300nm to 1100nm decreases with increasing the height of nanohillocks, whereas the internal quantum efficiency worsens. The solar cell based on the optimized nanohillocks height of 300nm yeilds efficiency of 15.99% with short circuit current of 34.0mA/cm2. [Copyright &y& Elsevier]

Abstract: Optimized textured structure is one of the most important elements for high efficiency multicrystalline silicon solar cells. In this paper, in order to incorporate low reflectance nanostructures into conventional industrial solar cells, structures with aspect ratios of about 1:1 and average reflectance of 8.0% have been generated using plasma immersion ion implantation. A sheet resistance of 56.9Ω/sq has been obtained by adjusting the phosphorous diffusion conditions, while the thickness of the silicon nitride vary in 70–80nm by extending the deposition time by 100s. Under the conventional co-firing conditions, a solar cell with efficiency of 16.3% and short-circuit current density 34.23mA/cm2 has been fabricated. [Copyright &y& Elsevier]

Abstract: The black silicon has been produced by plasma immersion ion implantation (PIII) process. The microstructure and optical reflectance are characterized by field emission scanning electron microscope and spectrophotometer. Results show that the black silicon appears porous or needle-like microstructure with the average reflectance of 4.87% and 2.12%, respectively. The surface state is investigated by X-ray photoelectron spectroscopy (XPS) technique. The surface of the black silicon is composed of silicon, carbon, oxygen and fluorine element. The formation of Si x O y F z in the surface of black silicon can be proved clearly by the O 1s, F 1s and Si 2p XPS spectra. The formation mechanism of the black silicon produced by PIII process can be obtained from XPS results. The porous or needle-like structure of the black silicon will be formed under the competition of SF x + (x ≤5) and F+ ions etching effect, Si x O y F z passivation and ion bombardment. [Copyright &y& Elsevier]

Abstract: In the present study, the black silicon has been successfully produced by plasma immersion ion implantation (PIII). The microstructure and the reflectance of the black silicon have been investigated by field emission scanning electron microscope and spectrophotometer, respectively. Results show that the black silicon exhibits a needle-like structure with the average reflectance of 1.79%. The solar cell based on black silicon yields an efficiency of 15.68% with a fill factor (FF) of 0.783. [Copyright &y& Elsevier]

Abstract: It is a major issue to improve the thermo-mechanical sensitivity of uncooled optomechanical focal plane arrays (FPAs) for infrared imaging. This work presents an optimized multi-fold interval metallized leg (IML) configuration to increase the thermo-mechanical sensitivity of an uncooled optomechanical bi-material micro-cantilever array. The inclination angle changes of the cantilever elements are measured in the IR imaging system using an optical readout with a knife-edge filtering operation in the spectrum plane. The multi-fold IML configuration consists of alternately connected unmetallized and metallized legs. With the optimized fold number, the thermo-mechanical sensitivity of a micro-cantilever array can be amplified to two times of one-fold IML for a 120μm×120μm element with 1μm thick SiN x /0.2μm thick Au films. Room temperature objects are imaged with the fabricated FPA containing 160×160 elements and a 12-bit CCD. Further modeling analysis shows that the experimental results are well accordant with the theoretical calculation. An important practical feature of the implemented approach is its straightforward fabrication for a large FPA, without growing complexity and cost. [Copyright &y& Elsevier]

Abstract: In this study, we present an uncooled infrared imaging detector using knife-edge filter optical readout method. The tilt angle change of each cantilever in a focal plane array (FPA) can be simultaneously detected with a resolution of 10−5°. A deformation magnifying substrate-free microcantilever unit is specially designed. The multi-fold legs of microcantilever are interval metal coated to form a thermal deformation magnifying structure. Thermal and thermomechanical performance of this microcantilever unit are modeled and analyzed. An FPA with 100×100 pixels is fabricated and thermal images of human body are obtained by this detector. [Copyright &y& Elsevier]

Abstract: The thermal imaging performance of bi-material microcantilever uncooled infrared focal plane array depends on its thermal deformation sensitivity (the ratio of the microcantilever deformation to a temperature change of thermal objects). In this paper, two microcantilever arrays with different structures are designed and fabricated, which contain multi-fold interval metallized legs. The thermo-inducing incline angle of the microcantilever is measured by knife-edge filtering optical readout method. One of the structures has deformation magnification effect, which can magnify the incline angle of microcantilevers under the same temperature rise. The other structure aims at keeping microcantilevers from the influence of environmental temperature fluctuation. The performance of the microcantilever structures is modeled. Thermal images of human body are obtained with the fabricated microcantilever arrays. The thermal deformation sensitivities of two structures are measured, which agree with the modeling analyses. [Copyright &y& Elsevier]

Abstract: This paper describes a novel single-layer bi-material cantilever microstructure without silicon (Si) substrate for focal plane array (FPA) application in uncooled optomechanical infrared imaging system (UOIIS). The UOIIS, responding to the radiate infrared (IR) source with spectral range from 8 to 14μm, may receive an IR image through visible optical readout method. The temperature distribution of the IR source could be obtained by measuring the thermal–mechanical rotation angle distribution of every pixel in the cantilever array, which is consisted of two materials with mismatching thermal expansion coefficients. In order to obtain a high detection to the IR object, gold (Au) film is coated alternately on silicon nitride (SiN x ) film in the flection beams of the cantilevers. And a thermal–mechanical model for such cantilever microstructure is proposed. The thermal and thermal–mechanical coupling field characteristics of the cantilever array structure are optimized through numerical analysis method and simulated by using the finite element simulation method. The thermal–mechanical rotation angle simulated and thermal–mechanical sensitivity tested in the experiment are 2.459×10−3 and 3.322×10−4 rad/K, respectively, generally in good agreement with what the thermal–mechanical model and numerical analysis forecast, which offers an effective reference for FPA structure parameters design in UOIIS. [Copyright &y& Elsevier]

Abstract: In this paper, we report a simple method to produce micro/nano dual-scale textured silicon surfaces by combining alkaline etching with plasma surface processing. The surface morphologies were investigated by a field emission scanning electron microscope, while the surface reflectance and wettability were examined by a UV–VIS-NIR spectrophotometer and a drop shape analysis system, respectively. Results show that random nano-scale needle-like structures have been formed on micro-scale pyramids. The average reflectance and contact angle are 2.8% and ~120°, respectively. The solar cell based on the dual-scale textured silicon yields a high efficiency of 17.5% with a short circuit current density of 36.0mA/cm2. [Copyright &y& Elsevier]

Li 4 Ti 5 O 12 (LTO) nanoparticles coated with two types of carbon were synthesized for the anode of lithium ion batteries (LIBs). One type was LTO coated with crystalline carbon from graphite-based mesocarbon microbeads (LTO-MCMB), and the other type was LTO coated with amorphous carbon (LTO-AMC). Transmission electron microscopy (TEM) results indicate that MCMB and amorphous carbon were uniformly coated on the LTO nanoparticles surface using a facile solid-state synthesis method. Electrochemical characterization results show that the rate capability and cycle performance of LTO-MCMB were better than those of LTO-AMC. For example, at an extremely fast charge and discharge rate of 20C (~3 min charge or discharge), LTO-MCMB with 3 wt% MCMB still maintained a high specific capacity of 117 mAh g−1, compared with 91 mAh g−1 for LTO-AMC, demonstrating that particle surface engineering at the nanoscale is an efficient method to improve the energy storage performance of the anode material. Unlabelled Image • A solid-state method to synthesize Li 4 Ti 5 O 12 nanoparticles coated with C • The crystalline C coating improved electric conductivity and Li ion diffusivity. • The optimal crystalline C coating is 3 wt% and ~1.2 nm thickness. [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]