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The Laser Interferometer Space Antenna (LISA) mission, scheduled for launch in the mid-2030s, is a gravitational wave space observatory designed to detect sources emitting in the millihertz band. LISA is an European Space Agency flagship mission, currently entering the Phase-B development phase. It is expected to help us improve our understanding of our Universe by measuring gravitational wave sources of different types, with some of the sources being at very high redshifts (z∼20). On February 23, 2022, we organized the first LISA in Greece Workshop. This Workshop aimed to inform the Greek scientific and tech industry communities about the possibilities of participating in LISA science and the LISA mission, with the support of the Hellenic Space Center. In this White Paper, we summarize the outcomes of the Workshop, the most important aspect of it being the inclusion of 15 Greek researchers to the LISA Consortium, raising our total number to 22. At the same time, we present a road map with the future steps and actions of the Greek Gravitational Wave community with respect to the LISA mission. [ABSTRACT FROM AUTHOR]

A thermal stability analysis method of meta-aramid insulating paper based on computer molecular dynamics technology is designed in this paper. First, the raw materials and equipment for preparing meta-aramid insulating paper were determined to prepare meta-aramid insulating paper. Then, the internal structure and morphology of meta-aramid insulating paper are analyzed for the subsequent stability analysis. Finally, the basic principle of computer molecular dynamics technology is analyzed, which is used to analyze the thermal stability of meta-aramid insulating paper, mainly from the stability of its crystal region. The experimental results show that the proposed method is effective and feasible in analyzing the thermal stability of aramid insulating paper between samples. [ABSTRACT FROM AUTHOR]

In recent times, among all the substrates used in microfluidic systems, cellulose paper is used as a handy, low-cost substrate that has gained attention for carrying fluid on its surface over capillary pressure. Cellulose paper substrate has exhibited great potential on microfluidic devices owing to prevalent obtainability, easy fluid (sample) flow system, flexibility, and low cost. Cellulose paper is fibrous, biocompatible, and hydrophilic in nature due to the hydroxyl group of the cellulose molecule. Based on the dominance of functional hydroxyl groups, cellulose is very reactive and every single cellulose fiber acts like a microchannel on the paper substrates. Aggregation of inter- and intra-cellulose fiber chains has a strong binding affinity to it and toward materials containing hydroxyls groups. In this paper, impact of inter- and intra-cellulose fiber on the paper substrate has been discussed through an experimental study. For the addition of work a "hydrophobic penetration-on-paper substrate (Hyp-POP)" method has been shown by using TiO2 ink as a hydrophobic material to design the microfluidic channel on the Whatman cellulose filter paper (grade 1) as a paper substrate. In this experimental study, the intra-cellulose fibers of paper substrate interact through hydrogen bonds with water molecules and form a hydrophilic surface on paper substrate while TiO2 binds with intra-cellulose fibers by electrostatic forces which change the crystallinity of intra-cellulose fiber and make the surface of paper substrate; hydrophobic. Field Emission Scanning Electron Microscope (FESEM) analysis is conceded for microfluidic channel analysis on the paper surface and EDS is carried out for TiO2 ink contents analysis. It has been experimentally observed that the printing material of TiO2 ink with 17.2% Ti content is suitable to integrate hydrophobic barrier on paper substrate for microfluidic channel fabrication. The wetting ability of Whatman cellulose filter paper (grade 1) was further evaluated by contact angle measurements (Data physics OCA 15EC). Using "Hyp-POP" method a hydrophobic pattern (width 3140 μ m) on paper substrate has been made for the flow of liquid (blue fountain ink) into a paper fluidic channel (width 1860 μ m) without any leakage. [ABSTRACT FROM AUTHOR]

With the prevalence of artificial intelligence technologies, big data has been utilized to higher extent in many cross-domain fields. This paper concentrates on the digital assessment of vocational education level in some specific areas, and proposes a graph neural network-based assessment model for this purpose. Assume that all vocational colleges inside a specific region are with a social graph, in which each college is a node and the relations among them are the edges. The graph neural network (GNN) model is formulated to capture global structured features of all the nodes together. The GNN is then employed for the sequential modeling pattern, and the evolving characteristics of all the colleges can be captured. Some experiments are also conducted to evaluate the performance of the proposed GNN-VEL. It is compared with two typical forecasting methods under evaluation of two metrics. The results show that it performs better than other two methods. [ABSTRACT FROM AUTHOR]

This paper provides a review of the literature on rigorous definitions and constructions in quantum field theory (QFT), spanning the period of seven decades. Compared with the ideas and constructions found in the modern physics literature, we conclude that none of the existing systems of QFT axioms can cover all the physical situations. Therefore, it is still an outstanding open problem to formulate a complete definition of QFT. We argue that the question is of relevance for both physicists and mathematicians. [ABSTRACT FROM AUTHOR]

Nonlinear optical imaging is a versatile tool that has been proven to be exceptionally useful in various research fields. However, due to the use of photomultiplier tubes (PMTs), the wide application of nonlinear optical imaging is limited by the incapability of imaging under ambient light. In this paper, we propose and demonstrate a new optical imaging detection method based on optical parametric amplification (OPA). As a nonlinear optical process, OPA intrinsically rejects ambient light photons by coherence gating. Periodical poled lithium niobate (PPLN) crystals are used in this study as the media for OPA. Compared to bulk nonlinear optical crystals, PPLN crystals support the generation of OPA signal with lower pump power. Therefore, this characteristic of PPLN crystals is particularly beneficial when using high-repetition-rate lasers, which facilitate high-speed optical signal detection, such as in spectroscopy and imaging. A PPLN-based OPA system was built to amplify the emitted imaging signal from second harmonic generation (SHG) and coherent anti-Stokes Raman scattering (CARS) microscopy imaging, and the amplified optical signal was strong enough to be detected by a biased photodiode under ordinary room light conditions. With OPA detection, ambient-light-on SHG and CARS imaging becomes possible, and achieves a similar result as PMT detection under strictly dark environments. These results demonstrate that OPA can be used as a substitute for PMTs in nonlinear optical imaging to adapt it to various applications with complex lighting conditions. [ABSTRACT FROM AUTHOR]

The MINimal emission FLUXes (MINFLUX) technique in optical microscopy, widely recognized as the next innovative fluorescence microscopy method, claims a spatial resolution of 1–3 nm in both dead and living cells. To make use of the full resolution of the MINFLUX microscope, it is important to select appropriate fluorescence probes and labeling strategies, especially in living-cell imaging. This paper mainly focuses on recent applications and developments of fluorescence probes and the relevant labeling strategy for MINFLUX microscopy. Moreover, we discuss the deficiencies that need to be addressed in the future and a plan for the possible progression of MINFLUX to help investigators who have been involved in or are just starting in the field of super-resolution imaging microscopy with theoretical support. [ABSTRACT FROM AUTHOR]

We report on the fabrication of zinc oxide (ZnO) nanorod-based flexible, cost-effective single electrode triboelectric nanogenerator (STENG) on cellulose paper platform. In particular, the influence of surface functional groups of ZnO nanorods on the STENG output has been investigated. The STENG has been designed with chemically grown ZnO nanorod-coated paper as active triboelectric layer and Teflon/ Aluminum as counter triboelectric layer/ electrode. It has been found that post-annealing of nanorods at 125∘C improves the output voltage by twice compared to the pristine nanorods and delivers an output power of ∼ 0. 2 μ W/cm2. With annealing up to 125∘C, the optimal removal of the chemisorbed water from the defect sites of ZnO surface increases the intrinsic carrier concentration leading to maximum charge transfer and hence higher triboelectric output. On the other hand, a higher extent of oxygen accumulation from air at 150∘C lowers the intrinsic carrier concentration resulting in the reduced output. It has been proposed that the competition between the events like water removal and oxygen accumulation under different annealing temperatures can influence the STENG output largely. Finally, the optimized STENG has been demonstrated to work as wearable bio-mechanical sensors operating through bio-mechanical stimuli. [ABSTRACT FROM AUTHOR]

The oil-immersed transformer is a crucial piece of equipment in the power system. Operating at the specified temperature is necessary to ensure the normal operation of the transformer. The insulation paper on the winding surface has a significant impact on the actual temperature of the transformers, which is often overlooked by researchers. The one-dimensional steady-state heat conduction model of the transformer is established by analyzing the heat diffusion process of winding to transformer oil. Atomic force microscope was used to observe the microsurface structure of insulation paper and copper. According to the experiment, the heat transfer resistance in the series process of heat transfer at 7 0 ∘ C is 0.0138 m2 K/W. Space thermal circuit model of transformer is established by thermoelectricity analogy method, and the simulation circuit is optimized according to the boundary conditions set up in the actual environment. The results show that the error of the hot spot temperature is closer to the measured temperature and decreases by 2.5% when considering the thermal resistance of insulation paper. [ABSTRACT FROM AUTHOR]

We study Kauffman's model of folded ribbon knots: knots made of a thin strip of paper folded flat in the plane. The folded ribbonlength is the length to width ratio of such a folded ribbon knot. The folded ribbon knot is also a framed knot, and the ribbon linking number is the linking number of the knot and one boundary component of the ribbon. We find the minimum folded ribbonlength for 3 -stick unknots with ribbon linking numbers ± 1 and ± 3 , and we prove that the minimum folded ribbonlength for n -gons with obtuse interior angles is achieved when the n -gon is regular. Among other results, we prove that the minimum folded ribbonlength of any folded ribbon unknot which is a topological annulus with ribbon linking number ± n is bounded from above by 2 n. [ABSTRACT FROM AUTHOR]

The work aims to explore a microscopic observation system of paper surface and achieve high-precision stereoscopic observation with detail characterization of paper surface morphology. Based on the DT-400E precision program-controlled three-dimensional translation stage and KEYENCE LJV-7200 two-dimensional laser scanner, the hardware parts of our own system are developed to scan and transmit point cloud data of paper surface morphology to the computer. The corresponding system software will automatically process the point cloud data acquired from the laser scanner and generate the corresponding vivid 3D model and height histogram. This system scans and characterizes four different types of paper samples, allowing the human eye to visually distinguish the differences in surface morphology as well as automatically calculate the numerical differences in paper surface morphology parameters. The results of the applicability test show that the system is highly efficient in acquiring, observing, and evaluating the topography of the paper surface. The system can not only predict the paper surface quality of printed paper, but can also be extended to the evaluation of 3D printed surfaces. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to retrieve and study the highly cited papers as well as the correlation between the citation frequency and the download frequency of the 20 traditional Chinese medicine journals in China, in order to provide the guidance for improving the influence and academic quality of these journals. Bibliometric analyses were conducted on 1103 papers of 20 traditional Chinese medicine journals from 2011 to 2020 by retrieving for the China Academic Journal Network Publishing Database (CAJD) in China National Knowledge Infrastructure (CNKI). SPSS 17.0 software was used to analyze the correlation between the citation frequency and the download frequency via conducting regression fitting and establishing the mathematical models. The results showed that the total citations of the 1103 papers were 93051 times and the average citations were 84.36 times per paper. The total downloads of the 1103 papers were 2058442 times, and the average downloads were 1866.22 times per paper. China Journal of Chinese Materia Medica ranked first according to the number of papers, total citations and total downloads. The citations of Journal of Chinese Medicinal Materials ranked first based on the number of citations per paper. One of Li's paper had been cited the most (983 times). There were 629 (57.03%) papers whose first author was from universities. The scopes of the first authors were distributed in 29 regions and 2 special administrative regions (Macao, Hong Kong) in China. The authors from Beijing published 283 (25.66%) papers, ranking number one. The number of papers supported by funds was 882 (79.96%). The research results of correlation showed that the citation frequency and the download frequency of the highly cited papers had a highly positive correlation from both journal and paper level for whether the sample data of journals was normally distributed or nonnormally distributed. The correlation coefficients of the 20 journals at journal level and that at paper level were 0.9765 and 0.6677, respectively. The correlation was better at journal level than that at paper level, while the optimal regression fitting was all cubic polynomial. Among the 1103 papers, there were 684 (62.01%) research papers and 419 (37.99%) review papers. The main citation period of the top 15 papers was from the 2nd year to the 6th year after publication, accounting for 78.39%. Papers on clinical therapeutics research, papers on the pharmacological effects and its mechanism of traditional Chinese medicine, and papers on traditional Chinese medicine and natural medicine were the main source of the highly cited papers of the traditional Chinese medicine journals. Editors of the journals should focus on the above-mentioned research areas to select manuscripts for exploiting the excellent sources extensively, while paying attention to review papers, focusing on national major or key projects, paying attention to network spreading, stabilizing authors with quality services, in order to improve the influence and the academic quality of journals. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries have received considerable attention as energy storage tool for modern-life equipments. However, drawbacks like low electric conductivity and volume expansion are the obstacles that hinder its application. To solve these problems, we developed a facile method using waste eggshell as hard template to reduce its particle size and change its morphology by simple hydrothermal process. Then, by utilizing waste paper, conductive paper (CP) current collector with graphene and multiwalled carbon nanotube implanted was prepared and combined with MnO2 anode material. The composite anode shows extraordinary electrochemical performances like much smaller impedance, high reversible capacity of 1767/1762 mAh/g even after 200 cycles at 100 mA/g, superior rate performance, etc. Compared with anode using metal current collectors, this composite anode will reduce weight and can be generalized to other high energy storage applications. Our environment-friendly method has far-reaching referential significance to other active materials and battery systems. A composite electrode, with δ -MnO2 as active material and conductive paper as current collector, has been synthesized and used in lithium-ion battery. Waste eggshell and waste paper were used in the synthetic process to protect environment. The electrode is much lighter and has much better electrochemical performances. This method can be generalized to other active materials and battery systems. [ABSTRACT FROM AUTHOR]

To address the issues in clothing pattern style migration, this paper proposes a digital simulation and re-editing method for clothing patterns based on deep learning and somatosensory interaction. First, the proposed method encodes the black-and-white line drawing image, generating random noise images through a diffusion process, introducing color information for synthesis, and using a decoder to reconstruct a colored image. Afterwards, an improved VGG19 model is used to reconstruct content features and perform linear color transformation on style images, enabling pattern style migration through the construction of a Gram matrix and resulting in colored clothing texture patterns. Finally, a KinectV2 is utilized for fabric simulation, overlaying colorful clothing texture patterns to achieve 3D virtual dressing. The experimental results show that the proposed method improves the structural similarity index measure (SSIM) by 9–11% and the peak signal-to-noise ratio (PSNR) by 3–8% when compared to existing algorithms. The experiments provide evidence that the proposed method effectively mitigates color overflow, delivers precise image coloring, and accomplishes realistic restoration of clothing texture. Furthermore, the method offers an improved garment fit to fulfill the user's interaction requirements. [ABSTRACT FROM AUTHOR]

Organic transistors are crucial components in future flexible electronics due to their excellent properties and ease of circuit integration. Previously, we demonstrated that flexible organic (polyimide) thermal transistors could be prepared using commercial graphite paper as the substrate. These materials exhibited excellent temperature sensitivity, linearity and recoverability due to the intrinsically high thermal conductivity of graphite. In this study, boron nitride (BN) sheets/polyimide hybrid dielectric layers were synthesized for the fabrication of flexible organic transistors using a commercial graphite paper. Under test, the results showed that the introduction of BN sheets was beneficial in improving the mobility and transistor characteristics of the device, as well as enhancing the overall stability. The as-fabricated transistors virtually exhibited no hysteresis at all BN contents. Boron nitride (BN) sheets were added to the fluorinated polyimide (FPI) matrix to form hybrid dielectric layer for improving the performance of flexible organic transistors fabricated on commercial graphite paper. The results showed that the device with BN/FPI hybrid dielectric layer exhibited higher output current (Id) and stability. Besides, the devices remained hysteresis-free at all tested BN sheet contents. [ABSTRACT FROM AUTHOR]

The manufacturing procedures of sandwich composites containing corrugated paper (CP) as a core layer and covered with glass fabrics are discussed herein. The core layer of the sandwich composite was fabricated with CP-reinforced epoxy (E) resin and then stacked with glass fabric on the top and bottom surfaces to fabricate the sandwich composites. Three composites [a CP-reinforced E (CP/E) composite, glass fiber nonwoven mat (GN) sandwich composite with a CP core layer (GN/E/CP) and glass mesh fabric (GM) sandwich composite with a CP core layer (GM/E/CP)] were developed in this study. The bending and compression properties of these sandwich composites were measured on a materials test system. Experimental results revealed that the bending strength of the GN/E/CP sandwich composite was approximately 45% and 150% higher than those of the GM/E/CP and CP/E sandwich composites, respectively. [ABSTRACT FROM AUTHOR]

A nanoflower structure of Zn 0. 7 6 Co 0. 2 4 S directly grown on carbon fiber papers (CFP) was successfully designed by a mild two-step hydrothermal method. Benefiting from their fascinating structural features, Zn 0. 7 6 Co 0. 2 4 S/CFP electrode exhibits a maximum specific capacitance of 300 F g − 1 at current density of 1 A g − 1 and 84% capacitance retention after 5,000 cycles at current density of 5 A g − 1 . Subsequently, Zn 0. 7 6 Co 0. 2 4 S/CFP//AC all-solid-state asymmetric supercapacitor (ASC) device is assembled and able to illuminate the red LEDs. ASC devices deliver a maximum energy density of 9.59 W h kg − 1 at a power density of 750 W kg − 1 . Therefore, this impressive result demonstrates that the nanoflower Zn 0. 7 6 Co 0. 2 4 S have promising applications in the development of high-performance supercapacitors. Zn0.76Co0.24S/CFP was obtained using two-step hydrothermal method. Its microstructure presents a novel nanoflower arrays. The synergistic effect between Zn0.76Co0.24S nanoflower and CFP improves the electrons transport efficiency, conductivity and structural stability of the hybrid. The as-prepared Zn0.76Co0.24S/CFP electrode delivers a specific capacitances of 300 F g−1 and exhibits an excellent cycling stability (retaining 84% after 5000 cycles) as well as a high energy density of 9.59 W h kg−1. [ABSTRACT FROM AUTHOR]

Despite the resistance-type gas sensors attracting intensive research interest, the vulnerability to the interference of humidity is a great challenge for their large-scale productions and applications. Herein, a convenient "gas-sensitized sensing material + adhesive" approach for the fabrication of superhydrophobic interface has been proposed to settle the problem. The multiwalled carbon nanotubes (MWCNTs)/styrene-ethylene/butylene-styrene block copolymer (SEBS) layer formed by spraying the cyclohexane suspension of MWCNTs and SEBS with micro/nanostructure endows the sensor with outstanding superhydrophobic property, presenting that the apparent contact angles (CA) are up to 179.6∘. The superhydrophobic paper sensor exhibited high sensing performance for acetone vapor and most importantly exceptional anti-humidity. The response of as-prepared sensor for other gaseous chemicals was consistent with that of MWCNTs, which indicated that the "gas-sensitized sensing material + adhesive " approach did not change the MWCNTs gas-sensitive characteristics. The approach builds an efficient bridge between gas-sensitive particles and flexible, superhydrophobic systems, inspiring a new simple way to the development of gas sensor with high immunity to humidity. A convenient "gas sensitized sensing material + adhesive" approach was proposed to form superhydrophobic paper sensor, which not only has outstanding superhydrophobic property, presenting that the apparent contact angle is up to 179.6∘, but also preserves the gas sensitized sensing material origin gas-sensitive characteristics. [ABSTRACT FROM AUTHOR]

In this work, a solely gravity and capillary force-driven flow chemiluminescence (GCF-CL) paper-based microfluidic device has been proved for the first time as a new platform for inexpensive, usable, minimally-instrumented dynamic chemiluminescence (CL) detection of chromium (III) [Cr(III)], where an appropriate angle of inclination between the loading and detection zones on the paper produces a rapid flow of CL prompt solution through the paper channel. For this study, we use a cost-effective paper device that is manufactured by a simple wax screen-printing method, while the signal generated from the Cr(III)-catalyzed oxidation of luminol by H2O2 is recorded by a low-cost and luggable CCD camera. A series of GCF-CL affecting factors have been evaluated carefully. At optimal conditions, two linear relationships between GCF-CL intensities and the logarithms of Cr(III) concentrations are obtained in the concentration ranges of 0.025–35 mg/L and 50–500 mg/L separately, with the detection limit of 0.0245 mg/L for a less than 30 s assay, and relative standard deviations (RSDs) of 3.8%, 4.5% and 2.3% for 0.75, 5 and 50 mg/L of Cr(III) (n = 8). The above results indicate that the GCF-CL paper-based microfluidic device possesses a receivable sensitivity, dynamic range, storage stability and reproducibility. Finally, the developed GCF-CL is utilized for Cr(III) detection in real water samples. [ABSTRACT FROM AUTHOR]

The waterproof and flame-retardant properties of corrugated paper (CP) reinforced epoxy resin sandwich composites are discussed. Two composites, a CP-reinforced epoxy composite (CP/E composite) and a CP-reinforced flame-retardant epoxy composite (CP/FRE composite), were developed in this study. A dipping bath was developed for impregnating the paper with epoxy and a flame-retardant epoxy solution to make the CP/P and CP/FRE composite panels. A room-temperature-cured epoxy resin was blended with various contents (10%, 20%, and 30%) of phosphorus-based flame-retardant compounds and then was used as a matrix to make CP/FRE-10, CP/FRE-20, and CP/FRE-30 composite materials. Water absorption tests of these composites were used to estimate the waterproof properties. In addition, vertical and horizontal burning tests were used to evaluate the flame-retardant properties of the composites. [ABSTRACT FROM AUTHOR]

The tensile and compressive properties of jute fabric and corrugated paper (CP)-reinforced polylactic acid (PLA) resin sandwich composites are discussed. A core layer was fabricated with CP-reinforced PLA resin. The core later was then stacked with jute fabric and PLA films on the top and bottom surfaces to fabricate the sandwich composites. Two composites, a CP-reinforced PLA composite (CP/PLA composite) and a jute fabric/PLA sandwich composite with CP as a core layer (J/PLA/CP composite) were developed in this study. A dipping bath was developed for impregnating the paper with a molten PLA solution to make the CP/PLA composite core layer. The resin film method was used to fabricate the jute fabric/PLA/CP sandwich composite on a hot press machine. A material test system (MTS810) was used to evaluate the tensile, flatwise compression, and longitudinal compressive characteristics of the composites. [ABSTRACT FROM AUTHOR]

The colorimetric method is usually used to test the concentration of substances. However, this method has a big error since different people have different sensitivities to colors. In this paper, in order to solve the identification problem of the color and the concentration of the test paper, firstly, we found out that the concentration of substance is correlated with the color reading by using the Pearson's Chi-squared test method. And by the concentration coefficient of Pearson correlation analysis, the concentration of substance and color reading is highly correlated. Secondly, according to the RGB value of the paper image, the color moments of the image are calculated as the characteristics of the image, and the Levenberg–Marquardt (LM) neural network is established to classify the concentration of the substance. The accuracy of the training set model is 94.5%, and the accuracy of the test set model is 87.5%. The model precision is high, and the model has stronger generalization ability. Therefore, according to the RGB value of the test paper image, it is effective to establish the LM neural network model to identify the substance concentration. [ABSTRACT FROM AUTHOR]

I point out a conceptually simple way of establishing one of the main lemmas in the paper "Solvability of equations in elementary functions" by A. Kanel-Belov, A. Malistov and R. Zaytsev. [ABSTRACT FROM AUTHOR]

In this study, we report the findings that the C-N composites containing Ni and Co (Ni1Co1/C-N, Ni3Co1/C-N, Ni6Co1/C-N, Ni9Co1/C-N, NiCo0/C-N and Ni0Co/C-N) can be produced by direct pyrolysis of the NiCo-doped polyaniline (PANI) precursors in N2 atmosphere at 800C and show efficient electroactivity for oxygen reduction reaction (ORR) in alkaline media. Distribution and compositions of the catalysts were characterized by SEM, TEM, EDS and XRD techniques. The catalysts were loaded on carbon paper to prepare gas diffusion electrodes, in which electrocatalytic activity for ORR in alkaline media was investigated by voltammetric techniques. The ORR current density on these carbon paper-supported NiCo/C-N catalysts exhibits a linear increase with the negative shift of ORR potential. The ORR onset potential is around 0.2V (versus Ag/AgCl) in alkaline media. Among the prepared catalysts, the catalyst Ni6Co1/C-N presents the largest ORR current density, which is 68.5mAcm@0.8V (versus Ag/AgCl) in alkaline media. Moreover, Ni6Co1/C-N catalyst also presents good electrocatalytic activity stability for ORR. Ni/Co-doped C-N nanocomposite catalysts were prepared by direct pyrolysis of the mixture containing Ni/Co salts and polyaniline. The electrochemical test mold was used to study the ORR activity of the catalysts NiCo/C-N loaded on carbon paper. One side of the carbon paper modified with catalyst was in contact with the electrolyte while the other side was in contact with air. Among the prepared catalysts, the Ni6Co1/C-N catalyst shows the largest ORR current density of 68.5 mA cm-2@-0.8 V and high activity stability of ORR in alkaline media. [ABSTRACT FROM AUTHOR]

The maximum vibration transmissibility of paper honeycomb sandwich structures with different sizes of honeycomb core under various static stresses was investigated using the sine frequency sweep test. The effects of the cell length of the honeycomb, the thickness of the sandwich structure, and the static stress on the maximum vibration transmissibility were evaluated and a linear polynomial equation for evaluating the maximum vibration transmissibility was obtained. The results show that the maximum vibration transmissibility increases steadily with the increase in the cell length of the honeycomb, the thickness of the sandwich structure, and the static stress. The proposed equation for the maximum vibration transmissibility is suitable for predicting the maximum vibration transmissibility of paper honeycomb sandwich structures. In addition, the fitted three-dimensional diagrams of the effects of the factors on the maximum vibration transmissibility derived from the evaluation equation were shown to be in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

A new method for colorimetric detection of solution concentration is presented. A paper-based microfluidic device was designed and made using printed circuit board technology. Detection zone patterns were designed and transferred to a printed circuit board by hollowing technology. The printed circuit board with patterns was stuck onto a copper sheet. The hollowed zone was filled with solid paraffin and then covered with a piece of filter paper. The paraffin wax was melted by heating the copper sheet and permeated into the filter paper. Solution to be detected was pipetted on the paper-based device with detective zones. The images of the detective zones were obtained using a microscope with charge-coupled device, which is used for calculating RGBI model to further obtain the solution concentration. Litmus was demonstrated in sample experiments. Results showed that maximum error of measured value of solution concentration to its true value is less than 2% using the presented method. [ABSTRACT FROM AUTHOR]

The bending and impacting characteristics of sandwich composites containing corrugated paper (CP) as a core layer are discussed herein. The core layer of the sandwich composite was fabricated with CP-reinforced polylactic acid (PLA) resin. The core layer was then stacked with jute fabric and PLA films on the top and bottom surfaces to fabricate the sandwich composites. Two composites [CP-reinforced PLA composite (CP/PLA composite)] and jute fabric/PLA sandwich composite with CP as a core layer [J/PLA/CP composite] were developed in this study. To manufacture the CP/PLA composite core layer, a dipping bath was used for impregnating the paper with a molten PLA solution. The resin film method combined with a hot press was used to produce the jute fabric/PLA/CP sandwich composites. A material test system (MTS810) was used to study the bending properties of the composites. Further, an IZOD impacting instrument was used to examine the impacting characteristics of the composites. Both the CP/PLA and jute fabric/PLA/CP sandwich composites increase the energy absorption capacity in the impact test. [ABSTRACT FROM AUTHOR]

We study Kauffman's model of folded ribbon knots: knots made of a thin strip of paper folded flat in the plane. The ribbonlength is the length to width ratio of such a folded ribbon knot. We show for any knot or link type that there exist constants c 1 , c 2 > 0 such that the ribbonlength is bounded above by c 1 Cr (K) 2 , and also by c 2 Cr (K) 3 / 2 . We use a different method for each bound. The constant c 1 is quite small in comparison to c 2 , and the first bound is lower than the second for knots and links with Cr (K) ≤ 12,748. [ABSTRACT FROM AUTHOR]

Let X be a projective variety of dimension n ≥ 1 over an algebraically closed field of arbitrary characteristic. We prove a Fujiki–Lieberman type theorem on the structure of the automorphism group of X. Let G be a group of zero entropy automorphisms of X and G 0 the set of elements in G which are isotopic to the identity. We show that after replacing G by a suitable finite-index subgroup, G / G 0 is a unipotent group of the derived length at most n − 1. This result was first proved by Dinh et al. for compact Kähler manifolds. [ABSTRACT FROM AUTHOR]

Gas sensors are essential devices to detect harmful gases that are present in the environment. Metal oxide semiconductors (MOSs) are used as sensing materials to detect harmful gases. Some of the metal oxides, like ZnO, SnO2, WO3, NiO, etc. have been used to detect the gases. This paper provides a theoretical study of gas sensing using MOSs. Many programs are available for the theoretical Density Functional Theory (DFT) approach. The theoretical calculation provides many properties about the sensing material, like electronic properties, magnetic properties, charge difference calculation, and Vander wall interaction between the sensing material surface and adsorbing molecule. The nanostructure provides better gas sensing performance due to its high surface-to-volume ratio. This paper is based on the DFT study and provides gas-sensing results using electronic properties. [ABSTRACT FROM AUTHOR]

In this paper, we study the localization of an electron in a binary quantum system formed by a pair of quantum dots (QDs). The traditional theoretical consideration of such systems is limited to the symmetrical case when QDs in such double quantum dot (DQD) are assumed identical in all respects. In this paper, we model the effects of breaking QD similarities in a DQD by studying two-dimensional (2D) DQDs as a double quantum well (DQW). This is done by solving the Schrödinger equation, with parameters chosen to describe an InAs/GaAs heterostructure. We calculate the energy spectrum of the electron confinement and the spectral distribution of localized/delocalized spatial states. Both symmetric and asymmetric QW shapes are considered and their effects are compared. The effects of symmetry breaking are explained within the framework of the two-level system theory. We delineate the QW weak and strong coupling cases in DQW. In particular, we show that the coherence in ideal DQW is unstable in the case of a weak QW coupling. Within the framework of the proposed approach, a charge qubit realized on a DQD is discussed and, as an example, a qubit based on an almost ideal DQD is proposed. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the dielectric constant of solutions of a polar liquid in a nonpolar solvent: chlorobenzene–benzene, chlorobenzene–hexane. The measurements were carried out at a wavelength λ = 1 2. 8 0 cm in the temperature range from − 8 0 ∘ C to 2 0 ∘ C. The studies were carried out using the dielectric spectroscopy method. This method allows a more detailed study of the dielectric properties of the objects of study due to the large equilibrium ("static") dielectric constant of the object. The temperature dependence of the dielectric relaxation time of molecules in the liquid and solid states of the studied solutions is determined. It has been established that with increasing concentration (0.300, 0.562, 0.794, 1.000 for a chlorobenzene–hexane solution and 0.179, 0.368, 0.567, 0.778, 1.000 for a chlorobenzene–benzene solution) of the halogen substituent, the relaxation time increases. The measurement results of dielectric constant ε ′ and absorption coefficient ε ′ ′ obtained for concentrated solutions chlorobenzene–benzene, chlorobenzene–n–hexane at wavelengths λ = 1 2 , 80 and λ = 3 , 2 6 cm at temperature 2 0 ∘ C are given in the paper. The static dielectric constant is obtained at a frequency of 1 MHz. The obtained experimental values ε ′ , ε ′ ′ and ε 0 of investigated systems in ( ε ′ , ε ′ ′ ) plane locate on the semi-circle the center of which is on ε ′ axis. In this case, the high-frequency limit value of ε ∞ dielectric coefficient exceeds the corresponding n2 refraction index square. The macroscopic and molecular relaxation times are calculated on the base of experimental data. The thermodynamic quantities characterizing the process of dielectric relaxation are calculated for solutions of chlorobenzene–benzene, chlorobenzene–hexane. It has been determined that the height of the potential barrier separating the two equilibrium positions of a polar molecule is greatest in the state of a pure polar liquid and decreases with dilution in a nonpolar solvent. [ABSTRACT FROM AUTHOR]

In this paper, we investigate a (3+1)-dimensional integrable fourth-order nonlinear equation that can model both the right- and left-going waves in a fluid. Based on the Hirota method, we derive three sets of the bilinear auto-Bäcklund transformations along with some analytic solutions. Through the extended homoclinic test approach, we obtain some breather solutions. We find that the breather propagates steadily along a straight line, with one hole and one peak in each period. Graphical investigation indicates that the coefficients in that equation affect the location and shape of the breather. Moreover, we construct some mixed lump–kink solutions. Fusion and fission between a lump wave and a kink soliton are analyzed graphically. The solutions addressed in this paper may be applied to mimic some complex waves in fluids. [ABSTRACT FROM AUTHOR]

In the 21st century, understanding the mechanism of high-temperature superconductivity has emerged as a pinnacle achievement in condensed matter physics, capturing the lifelong interest of numerous physicists. This paper endeavors to offer a theoretical elucidation for this mechanism, advancing the broader field of physics. Recognizing that high-temperature superconductivity is an aspect of condensed matter physics — underpinned by Maxwell's classical electromagnetic theory — we turn to theoretical mechanics and field theory, which are foundational perspectives in the contemporary scientific era. By framing Maxwell's classical electromagnetic theory within the context of theoretical mechanics and field theory, this paper not only sheds light on the mechanism of high-temperature superconductivity but also recasts Maxwell's theory within a purer theoretical mechanics and field theory domain. This represents a paradigmatic shift and cognitive transformation in physics. Furthermore, leveraging this theoretical mechanics and field theory interpretation of electromagnetic phenomena, we discern that electromagnetic phenomena can be more aptly explained without resorting to the concepts of charges and electric fields, leading to a reinterpretation of Coulomb's law. We propose that protons and electrons might exist as entities devoid of charge-specific attributes and negate the possibility of a strongly correlated particle system within them. [ABSTRACT FROM AUTHOR]

Over the years questions have arisen about T-ideals of (noncommutative) polynomials. But when evaluating a noncentral polynomial in subalgebras of matrices, one often has little control in determining the specific evaluations of the polynomial. One way of overcoming this difficulty in characteristic 0, is to reduce to multilinear polynomials and to utilize the representation theory of the symmetric group. But this technique is unavailable in characteristic p > 0. An alternative method, which succeeds, is the process of "hiking" a polynomial, in which one specializes its indeterminates in several stages, to obtain a polynomial in which Capelli polynomial is embedded, in order to get control on its evaluations. This method was utilized on homogeneous polynomials in the proof of Specht's conjecture for affine algebras over fields of positive characteristic. In this paper, we develop hiking further to nonhomogeneous polynomials, to apply to the "representability question." Kemer proved in 1988 that every affine relatively free PI algebra over an infinite field, is representable. In 2010, the first author of this paper proved more generally that every affine relatively free PI algebra over any commutative Noetherian unital ring is representable [A. Belov, Local finite basis property and local representability of varieties of associative rings, Izv. Russian Acad. Sci. (1) (2010) 3–134. English Translation Izv. Math. 74(1) (2010) 1–126]. We present a different, complete, proof, based on hiking nonhomogeneous polynomials, over finite fields. We then obtain the full result over a Noetherian commutative ring, using Noetherian induction on T-ideals. The bulk of the proof is for the case of a base field of positive characteristic. Here, whereas the usage of hiking is more direct than in proving Specht's conjecture, one must consider nonhomogeneous polynomials when the base ring is finite, which entails certain difficulties to be overcome. In Appendix A, we show how hiking can be adapted to prove the involutory versions, as well as various graded and nonassociative theorems. [ABSTRACT FROM AUTHOR]

In [V. I. Arnold, Simple singularities of curves, Proc. Steklov Inst. Math. 226(3) (1999) 20–28, Sec. 5, p. 32], Arnold writes: 'Classification of singularities of curves can be interpreted in dual terms as a description of "co-artin" subalgebras of finite co-dimension in the algebra of formal series in a single variable (up to isomorphism of the algebra of formal series)'. In the paper, such a description is obtained but up to isomorphism of algebraic curves (i.e. this description is finer). Let K be an algebraically closed field of arbitrary characteristic. The aim of the paper is to give a classification (up to isomorphism) of the set of subalgebras of the polynomial algebra K [ x ] that contains the ideal x m K [ x ] for some m ≥ 1. It is proven that the set = ∐ m , Γ (m , Γ) is a disjoint union of affine algebraic varieties (where Γ ∐ { 0 , m , m + 1 , ... } is the semigroup of the singularity and m − 1 is the Frobenius number). It is proven that each set (m , Γ) is an affine algebraic variety and explicit generators and defining relations are given for the algebra of regular functions on (m , Γ). An isomorphism criterion is given for the algebras in . For each algebra A ∈ (m , Γ) , explicit sets of generators and defining relations are given and the automorphism group Aut K (A) is explicitly described. The automorphism group of the algebra A is finite if and only if the algebra A is not isomorphic to a monomial algebra, and in this case | Aut K (A) | < dim K (A / A) where A is the conductor of A. The set of orders of the automorphism groups of the algebras in (m , Γ) is explicitly described. [ABSTRACT FROM AUTHOR]

This work investigates a prey–predator model featuring a Holling-type II functional response, in which the fear effect of predation on the prey species, as well as prey refuge, are considered. Specifically, the model assumes that the growth rate of the prey population decreases as a result of the fear of predators. Moreover, the detection of the predator by the prey species is subject to a delay known as the fear response delay, which is incorporated into the model. The paper establishes the preliminary conditions for the solution of the delayed model, including positivity, boundedness and permanence. The paper discusses the existence and stability of equilibrium points in the model. In particular, the paper considers the discrete delay as a bifurcation parameter, demonstrating that the system undergoes Hopf bifurcation at a critical value of the delay parameter. The direction and stability of periodic solutions are determined using central manifold and normal form theory. Additionally, the global stability of the model is established at axial and positive equilibrium points. An extensive numerical simulation is presented to validate the analytical findings, including the continuation of the equilibrium branch for positive equilibrium points. [ABSTRACT FROM AUTHOR]

Digital technologies sustain today's world. Every part of the world is working towards digital technologies, which none of us can eliminate. Enormous growth is achieved only by unexpected acceleration by digital technologies, including the Internet of Everything (IoE), Artificial Neural Networks (ANN), Machine Learning (ML), Internet of Things (IoT), Artificial Intelligence (AI), Deep Learning (DL), and many more. These technologies started occupying all the engineering sectors, including manufacturing. This paper focuses on tribology analysis related to manufacturing concerning various digital manufacturing technologies. The paper narration includes Tribology using digital technologies wherein the journals and patent landscape analysis abet them. In trend, Tribology utilizes all these technologies today and envisages its growth with the predominant technological invention in the border view. The survey of various literature reveals that only three digital technologies, including AI, ML, and ANN, are used by tribologists around the globe. Other Technologies like Evolutionary Algorithm (EA), Support Vector Machine (SVM), and Adaptive Neuro-Fuzzy Interference Systems (ANFIS) are not used predominantly. [ABSTRACT FROM AUTHOR]

The enhanced power graph of a group G is a simple undirected graph with vertex set G and two vertices are adjacent if they belong to the same cyclic subgroup. In this paper, we obtain the Laplacian spectrum of the enhanced power graph of certain non-abelian groups, viz. semidihedral, dihedral and generalized quaternion. Also, we obtained the metric dimension and the resolving polynomial of the enhanced power graphs of these groups. At the final part of this paper, we study the distant properties and the detour distant properties, namely: closure, interior, distance degree sequence, eccentric subgraph of the enhanced power graph of semidihedral group, dihedral group and generalized quaternion group, respectively. [ABSTRACT FROM AUTHOR]

The paper deals with the problem of obtaining a given dynamic behavior of simply supported bridge beams from the impact of rolling stock. Resonant vibrations of beams become a reality at high speeds if the train is formed of identical cars, which is typical for passenger trains. The phenomenon of suppression of beam vibrations by a train, known from publications, is possible only with an exact ratio of the length of the car and the beam. This significantly reduces the possibilities of choosing the necessary spans of beams. Consideration of issues of interaction in the "bridge–track—train" system for security purposes requires the involvement of a rather complex mathematical apparatus and appropriate software. The paper proposes a new method for determining the specified dynamic behavior of bridge beams, suitable for any spans and available to engineers at the stage of pre-design assignment of dynamic parameters of beams. The requirements that are necessary and sufficient conditions for preventing the resonance of bridge beams on the HSR are determined. At the same time, it does not require the involvement of software based on a complex mathematical technique. [ABSTRACT FROM AUTHOR]

The stationary random response characteristics of irregular quadrilateral plates under the base acceleration excitation are investigated in this paper. The computational model chosen in this paper is functionally graded graphene platelet reinforced composites (FG-GPLRC). Simultaneously, the material parameters are calculated employing the modified Halpin–Tsai model. A unified dynamic model based on the first-order shear deformation theory (FSDT) is proposed for FG-GPLRC irregular plates, where the displacement variables are considered as the first kind Chebyshev polynomials combined with coordinate transformation. The Chebyshev–Ritz method is utilized to derive the kinetic equations of irregular quadrilateral plates, and then the pseudo-excitation method (PEM) is employed to solve the stationary stochastic response of the system under the base acceleration excitation. The free vibration and stationary stochastic response of the plates under various boundaries are validated by a sufficient number of numerical studies, and the computational results display a favorable match with the published literature and finite element method (FEM), which verifies the correctness and reliability of the present method. Finally, a detailed parametric analysis of the stationary stochastic response characteristics of FG-GPLRC irregular quadrilateral plates is presented. The effects of various mass fractions, number of layers, geometric dimensions of GPL, and boundary constraints on the stationary stochastic vibration behaviors of FG-GPLRC irregular quadrilateral plates are considered. [ABSTRACT FROM AUTHOR]

Analytical methods provide crucial mathematical insights into the stable solitary waves hidden in nonlinear phenomena. The nonlinear Schrödinger (NLS) equation is one of the most important typical integrable soliton models. From a mathematical perspective, the essence of the celebrated derivative NLS (DNLS) equation’s difference from the classical NLS equation lies in its cubic potential being differentiated once by the spatial variable and multiplied by the imaginary unit, which leads to the former having some characteristics that the latter cannot have. This paper extends the DNLS equation to the fractional integrable case with conformable derivative operators, and uses Darboux transformations (DTs) and generalized DT (GDT) to solve it exactly. Specifically, Lax pairs generating the fractional DNLS equation are first given. Based on the given Lax pairs, then the n-fold DTs and GDT for the fractional DNLS equation are derived. Some special exact solutions of the fractional DNLS equation are further obtained by employing the derived n-fold DTs and GDT. Finally, several novel space–time structures and dynamical evolutions of the obtained exact solutions are analyzed. This paper reveals through the DT and GDT methods that the double power-law fractional orders in the exact solutions of the fractional DNLS equation can be used to dominate the variable velocity propagation and anomalous diffusion in fractional dimensional media at different geometric scales. [ABSTRACT FROM AUTHOR]

Smooth and discontinuous (SD) oscillators are the nonlinear models that will exhibit SD dynamics due to continuous variation of the smooth parameter. Kosambi–Cartan–Chern (KCC) theory is a differential geometric theory that describes the deviations from the entire trajectory of the variational equation to the nearby trajectory. This paper presents a completely new dynamical analysis of a type of SD oscillators with nonlinear damping based on the KCC theory. First, the paper gives five KCC geometrical invariants of SD oscillators in the smooth and non-smooth cases, respectively. The results show that the geometric quantities in the non-smooth case cannot be derived directly from the geometric quantities in the smooth case. Second, from these geometric quantities, KCC stability of SD oscillators trajectory at any point except x = 0 is analyzed. Lastly, numerical results show that in some regions that deviate from the equilibrium point of system, the system will exhibit complex and variable dynamical behavior due to small changes in parameters. This paper shows that the KCC theory is also a useful tool in the dynamical analysis of non-smooth systems. [ABSTRACT FROM AUTHOR]

Video anomaly detection has always been a challenging task in computer vision due to data imbalance and susceptibility to scene variations such as lighting and occlusions. In response to this challenge, this paper proposes an unsupervised video anomaly detection method based on an attention-enhanced memory network. The method utilizes a dual-stream network structure of autoencoders, enhancing the model’s learning ability for important features in appearance and motion by introducing coordinate attention mechanisms and variance attention mechanisms, emphasizing significant characteristics of static objects and rapidly moving regions. By adding memory modules to both the appearance and motion branches, the network structure’s memory information is reinforced, enabling it to capture long-term spatiotemporal dependencies in videos and thereby improving the accuracy of anomaly detection. Furthermore, by optimizing the network structure’s activation functions to handle negative inputs, it enhances its nonlinear modeling capabilities, enabling better adaptation to complex environments, including variations in lighting and occlusions, further improving the effectiveness of anomaly detection. The paper conducts comparative experiments and ablation studies using three public available datasets and various models. The results demonstrate that compared to baseline models, the AUC performance is improved by 3.9%, 4.7%, and 1.7% on UCSD Ped2, CHUK Avenue, and ShanghaiTech datasets, respectively. When compared with the other models, the average AUC performance is improved by 4.3%, 5.4%, and 6.2%, with an average improvement of 8.75% in the ERR metric, validating the effectiveness and adaptability of the proposed method. The code can be obtained at the following URL: https://github.com/AcademicWhite/AEMNet. [ABSTRACT FROM AUTHOR]

The influence of conjugate heat transfer based on radiation and magnetohydrodynamic utilization is an attractive research area, with progressive features; it has many applications in thermal engineering, heat exchangers, cooling phenomenon, magnetic cell separation, energy production, hyperthermia, etc. Following the motivating significances of the current research topic, this paper explores the influences of an electrically conducting and radiating fluid with internal friction, heat generation and thermal radiation embedded in a porous medium past a flat permeable plate. The boundary layer equations are dimensionally transformed and solved numerically using implicit finite difference technique called the Keller-box method. The effect of various fluid obeying parameters such as magnetic field, viscous dissipation and heat generation on the flow factors such as velocity and temperature are graphed and discussed in this paper. Growing heat source, energy inside the fluid boosts, thereby increasing the energy of the flow. Increase in generation of energy reduces the viscosity of the flow reduces thereby increasing the velocity of the flow particles. [ABSTRACT FROM AUTHOR]

This paper describes the fundamental characteristics of cavitation in non-Newtonian liquids and bubble dynamics and then applies them to the domains of bioengineering and biomedicine. The goal of this paper is to examine how Newtonian nanomaterial flows hydromagnetically when subjected to a spinning disc considering such biomedical and bioengineering applications. The vertical axis of the disc rotates with a uniform angular frequency. The fundamental mathematical expressions are governed by the Navier–Stokes equations with the Maxwell equations of magnetism, we obtained ordinary differential equations utilizing Von Kármán's similarity transformations. Additionally, the effects of the magnetic field and radiation restrictions are considered. The RK-4 technique is used to solve the transmuted nonlinear ODEs. The analysis of MATLAB generated flow profiles has looked for changes in the values of key parameters. It is discovered that an increase in the thermal radiation parameter causes a decrease in the nanofluid temperature while an increase in the volume fraction of magnetite nanoparticles causes an increase. The skin-friction and heat-transfer rate at the disc are highly influenced by its rotational, the porosity of the porous media, thermal radiation and nanoparticle size. The rotational parameter, which regulates the disk's rotation, is a result of the rotating phenomenon. The research demonstrates that when the disk's rotation increases, the fluid motion accelerates in both the radial and cross-radial directions. Additionally, increasing the Prandtl number significantly improves heat transport, and a higher value for the rotation parameter shows a lesser concentration phenomenon. Additionally, the Nusselt number shows a decrease curve for a changeable thermal conductivity parameter. Finally, the current research can effectively close a gap in the physique of knowledge. [ABSTRACT FROM AUTHOR]