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The value of the Buddhist cave lies not only in the Buddha statues but also in the surface painting. Hyperspectral imaging technology, as an emerging and effective method for component identification, offers a non-contact and non-destructive approach to the preservation and restoration of oil paintings. This study employed hyperspectral cameras to capture common pigments on the surfaces of Buddhist caves. Then, the results were processed and used as a database to identify the paintings. Additionally, a series of experiments were conducted to examine the impact of binder, substrate types, and pigment sizes on the reflectance spectrum of the paints. The Spectral Angle Matching (SAM) algorithm was then used to analyze the Yuanjue Cave and Qiqushan Stone Carvings of the Tang Dynasty in China. The findings revealed that the position of absorption peaks in the reflectance spectra is not significantly influenced by the substrate but is affected by the binder. Moreover, the absorption depth varies regularly with particle size. Furthermore, the spectral matching results demonstrate that components can be accurately identified even for similar colors. Based on the pigment distribution, the study also inferred specific details of ancient paintings, including the painting steps and hidden information in the manuscript layout. These findings hold significant implications for the restoration of representative surface paintings of the Tang Dynasty Buddhist cave, providing a reference for the selection of restoration materials and methods. [ABSTRACT FROM AUTHOR]

Circulating tumor DNA (ctDNA) appears as a valuable liquid biopsy biomarker in the early diagnosis, treatment, and prognosis of cancer. Here, a biosensing method derived from the AC electrokinetics (ACEK) effect was constructed in this study for the simple, efficient, and rapid method of detection of ctDNA. In the proof-of-concept experiment, ctDNA from the PIK3CA E542K mutant in breast cancer was quantified by detecting a normalized capacitance change rate using a forked-finger gold electrode as the sensing electrode in combination with the ACEK effect. We compared two formats for the construction of the approach by employing varied immobilization strategies; one is to immobilize the DNA capture probe on the electrode surface by Au–S bonding, while the other immobilizes the probe on a self-assembled membrane on the electrode surface by amide bonding. Both formats demonstrated ultrafast detection speed by completing the ctDNA quantification within 1 min and a linear range of 10 fM–10 pM was observed. Meanwhile, the immobilization via the self-assembled membrane yielded improved stability, sensitivity, and specificity than its Au–S bonding counterpart. A detection limit of 1.94 fM was eventually achieved using the optimized approach. This research provides a label-free and minute-scale universal method for the detection of various malignant tumors. The ctDNA biosensors based on the ACEK effect improved according to the probe type or electrode structure and have potential applications in tumor drug efficacy prediction, drug resistance monitoring, screening of high-risk groups, differential diagnosis, monitoring of tiny residual lesions, and prognosis determination. [ABSTRACT FROM AUTHOR]

Cysticercosis, caused by Taenia solium infection, is a leading cause of acquired epilepsy in many developing countries. Several types of immunoassays have been developed for the detection of Taenia solium infection in both infected humans and livestock animals. However, these methods require central laboratory facilities and are both time- and labor-consuming with longer than desired turnaround time. In this work, we demonstrated that AC electrokinetics (ACEK) capacitive sensing can be used to realize point-of-care immunosensor in general, with the on-site screening of Taenia solium infection as an example here. The sensor employs interdigitated microelectrodes (IDME) functionalized with a recombinant Taenia solium antigen, rT24H, to detect anti-rT24H antibodies in clinical serum samples. ACEK capacitive sensing method interrogates the IDME sensors with a special AC signal, which serves the dual purposes of enriching target antibodies by ACEK effects and directly measuring the capacitance change induced by specific binding. First, to characterize the ACEK biosensor as an immunosensor in general, IgG in phosphate-buffered saline buffer was tested against IDME sensors functionalized with anti-IgG. The limit of detection of the sensor was 24.1 fg/mL, and the linear dynamic range was 0.1–100 pg/mL. To test the clinical usage of this sensor, ACEK capacitive sensors with rT24H probe were used to test clinical serum samples from patients with or without Taenia solium infection. The diagnostic sensitivity of the ACEK capacitive sensor for Taenia solium infection was found to be 88.24%. ACEK capacitive immunosensors have shown good potential for point-of-care diagnostics. [ABSTRACT FROM AUTHOR]

Owing to simple implementation and excellent performance, the conventional stator flux observer based on active flux concept is considered as a competitive scheme for direct torque control system of a permanent magnet synchronous motor. However, it is constructed by a large number of motor parameters, which may vary with the operating points. This leads to weak robustness. To improve its performance, a stator flux observer with phase self-tuning is proposed as an improved version in this article. First, relationship between the stator flux observed values obtained by current and voltage models and observed error of rotor position angle is analyzed. Then, according to the aforementioned analysis, a phase self-tuning link constructed by a proportional-integral regulator is proposed to ensure that the observed coordinate system converges to the actual one even under motor parameters vary conditions. Consequently, the robustness and accuracy of the stator flux observer can be improved. Finally, the stability of the proposed phase self-tuning link is analyzed. Experimental comparison between the conventional stator flux observer based on active flux concept and the proposed improved stator flux observer has been done, and the results verify the feasibility and effectiveness of the proposed stator flux observer. [ABSTRACT FROM AUTHOR]

Direct torque control (DTC) has become a widely acceptable alternative to field-oriented control in permanent magnet synchronous motor (PMSM) drives. Deadbeat direct torque and flux control (DB-DTFC) is a significant improvement over the classical DTC. However, there are some aspects that can be improved, such as insufficiently small electromagnetic torque ripple, unsmooth dynamic response, heavy computation burden, and relatively weak robustness to motor parameters variation. To improve the operation performance, an advanced DB-DTFC strategy is proposed in this article. First, the algorithm model based on stator flux oriented coordinate system is deduced. On this basis, the basic principle of proposed DB-DTFC is presented. Second, a novel graphical analysis method is proposed to help illustrate the proposed strategy. Third, a general solution method is proposed to solve the reference stator voltage, which is a key variable for the DB-DTFC. Finally, the stability of system is analyzed. Theoretical and experimental comparisons between the proposed DB-DTFC and the conventional DB-DTFC are done. The results show that the performance in the aspects of electromagnetic torque and stator current ripples reduction, dynamic response, computation burden, and robustness to motor parameters variation are all improved in the proposed DB-DTFC. [ABSTRACT FROM AUTHOR]

This article introduces the classical direct torque control (DTC) to a three-phase open-end winding permanent magnet synchronous motor with common dc bus for the first time. The electromagnetic torque and the stator flux are controlled at the same time. However, the zero-sequence current is not suppressed, and the ripples of the electromagnetic torque and stator flux are large. To improve the operation performance of this drive system, a DTC based on a duty ratio modulation (DRM-DTC) is proposed. First, a deadbeat zero-sequence current controller is proposed in the DRM-DTC to suppress the zero-sequence current. Second, another strategy, which is based on a graphical analysis method and a simple deadbeat direct torque and flux controller, is proposed to optimize the duty ratio of the active voltage vector. Thus, the electromagnetic torque and stator flux ripples can be reduced. Finally, an optimized pulsewidth modulation implementation strategy is proposed in the DRM-DTC to further reduce the switching frequency of inverters. The classical DTC and the proposed DRM-DTC are compared through simulation and experiment, and the results verify the effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]

A position sensor is usually required in the existing fault‐tolerant direct torque control (FT‐DTC) system for the multiphase permanent magnet synchronous motor (PMSM). Thus, the volume, weight, and cost of the system is increased, and the reliability is decreased. The conventional high‐performance position sensorless strategies for the multiphase motor under fault‐free condition cannot be directly applied to FT‐DTC system. To improve this situation, a high‐speed position sensorless FT‐DTC strategy for a six‐phase symmetrical winding PMSM with two opened phases is proposed in this study. Firstly, modified variables and a new rotating coordinate system are defined to achieve the symmetrical and decoupled mathematical model. Secondly, a stator flux observer based on the modified variables and a new coordinate system is proposed. According to the current model of modified stator flux, the estimated modified stator current can be achieved. Then, the estimated error of the modified stator current is sent to the integrator of the modified stator flux observer to correct the voltage model. Finally, the proposed stator flux observer is applied in FT‐DTC for six‐phase PMSM with two opened phases to realize the position sensorless operation at high speed. The experimental results verify the feasibility and effectiveness of the proposed strategy. [ABSTRACT FROM AUTHOR]

Owing to high driving power, good controllability, and strong fault-tolerant ability, a three-phase open-end winding permanent magnet synchronous motor driven by a dual inverter with common dc bus is considered as a competitive solution. However, a path for zero-sequence current is provided in this drive topology. Thus, the system loss would be increased, and the maximum output power is limited. In order to suppress the zero-sequence current, a novel space vector pulsewidth modulation (SVPWM) strategy based on the hysteresis controller of zero-sequence current is proposed in this paper. The voltage vectors, whose polarity of zero-sequence voltages (ZSVs) is opposite with the polarity of zero-sequence current, are selected as the basic voltage vectors of SVPWM for fundamental plane. Meanwhile, the linear modulation range is analyzed. According to the analysis results, the proposed strategy has the advantage of wide linear modulation range of ZSV under the condition of high fundamental modulation ratio. The experimental results show that the zero-sequence current is effectively suppressed by the proposed modulation strategy. Furthermore, the comparative evaluation of the proposed modulation strategy, the conventional SVPWM, the SVPWM with zero ZSVs, and the zero vector redistribution SVPWM with zero-sequence current proportional-resonant controller is conducted to demonstrate the superiority of the proposed strategy. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO2) plays a key role in environmental protection and human health. Recently, molybdenum disulfide (MoS2) representative of novel 2D materials has been utilized to detect NO2 gas, still hindered by the weak response, high operation temperature, as well as poor recovery characteristics. Herein, we report a UV light-assisted, room-temperature, recoverable, sensitive and selective NO2 gas sensing based on few-layer MoS2 nanosheet-Au nanoparticle composites serving as the sensing layer. In the dark condition, the as-prepared MoS2-Au sensor showed a response of 10% toward 2.5 ppm NO2 more than two times larger than MoS2 one, arising from more reaction sites (spillover effect and produced interfaces) and smaller baseline resistance after Au incorporation. Undesirably, all sensors exhibited an incomplete recovery. When MoS2-Au sensors were exposed to NO2 gas under UV illumination, better performance in terms of three-time enhanced response, full recovery and favorable repeatability was achieved in comparison with that in the dark case. Two aspects were responsible for these phenomena. On one hand, additional photoinduced charge carriers ensured sufficient gas-solid interactions between sensing layer and target molecules, thereby resulting in a larger response. The other aspect lay in effective separation of these charge carriers at MoS2/Au interfaces, contributing to recoverable and repeatable reactions. MoS2-Au composites were adopted for NO2 detection under UV illumination and exhibited a promising capacity of UV photodetector as well as an inspiring room-temperature gas detection, which provided an alternative strategy to design a single optoelectronic device with multi-functions. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is an endocrine disrupting compound that may have adverse developmental, reproductive, neurological, and immune system effects. Low-level exposure to BPA is ubiquitous in human populations due to its widespread use in consumer products. Therefore, highly sensitive methods are needed to quantify BPA in various matrices including water, serum, and food products. In this study, we developed a simple, rapid, highly sensitive and specific sensor based on an aptamer probe and AC electrokinetics capacitive sensing method that successfully detected BPA at femto molar (fM) levels, which is an improvement over prior work by a factor of 10. We were able to detect BPA spiked in human serum as well as in maternal and cord blood within 30 s. The sensor is responsive to BPA down to femto molar levels, but not to structurally similar compounds including bisphenol F (BPF) or bisphenol S (BPS) even at much higher concentration. Further development of this platform may prove useful in monitoring exposure to BPA and other small molecules in various matrices. [ABSTRACT FROM AUTHOR]

We report the synthesis, characterization and gas sensing performance of reduced graphene oxide (RGO) and RGO/ZnO bilayer thin films prepared by facile sol-airbrush technology at room temperature. We found that RGO/ZnO bilayer films exhibit enhanced surface roughness and more spacing compared to RGO. Sensing performance measurements showed that RGO/ZnO film has 30% enhancement of Δ R/R 0 to chloroform vapor compared to pure RGO film due to the improvement of film structure. A slight enhancement of Δ R/R 0 was also observed on exposure to other vapors (water, ethanol, acetone and formaldehyde), with response and recovery time less than 10 s. To explore the stability of RGO film, we studied the effect of various flow rates of background gas on the electric resistance variation. It was found that electric resistance fell at a larger flow rate, rose at a smaller rate, and Δ R/R 0 became smaller after annealing. These results can be understood by the air pressure-induced deformation of RGO film. We further proposed a new method to calculate the sensing response, which was verified to be more reliable for sensing performance analysis with negligible hysteresis. We expect these findings to shed new light on future development of high-performance gas sensors based on bilayer films. [ABSTRACT FROM AUTHOR]

Hydrazine-reduced graphene oxide (RGO) film was further annealed for gas sensing investigation. Pristine RGO film with an initial n-type property underwent an n-p transition on dynamic exposure to NO 2 gas. After annealing at 300 °C, RGO film became p-type semi-conducting while the p-n transition behavior did not appear when immersed into target gases. Sensing mechanisms were studied combining with multiple characterization techniques such as SEM, EDS, XRD, Raman and FTIR by researching film differences before and after annealing. Interfering factors including operational temperature and relative humidity were contrastively analyzed as well. Besides, the effect of thermal annealing on relationship between flow rate of background gas and electric resistance variation was considered closely related to structural deformation of RGO film. The detailed and systematic investigation would enrich available gas-sensing mechanisms of RGO based sensors, and put forward some new scientific issues to be further studied, such as suppression of n-p or p - n transition and the concrete influence mode of film deformation on gas sensing. [ABSTRACT FROM AUTHOR]

A fault-tolerant direct torque control (DTC) strategy for six-phase symmetrical winding shifted-phase 60° permanent magnet synchronous motor with arbitrary two opened phases is proposed in this paper. First, the relationship between flux and electromagnetic torque based on the modified stator flux and modified rotor flux is researched. Second, the optimal control strategy based on the relationship between modified stator voltage vector and modified stator flux on αβ plane, and the relationship between zero-sequence voltage and zero-sequence current is constructed. According to the control strategy, the modified stator flux, electromagnetic torque, and zero-sequence current are controlled by different switching combinations of four-phase inverter bridge. The results of analysis and experiments show that the presented DTC drive system has fast and smooth torque response, and the four-phase stator currents with same peak value are sinusoidal due to the controlled zero sequence current. [ABSTRACT FROM PUBLISHER]

Tubeimoside (TBMS), the bulb of Bolbostemma paniculatum (Maxim.) Franquet (Cucurbitaceae), is one of the traditional Chinese medicines often used for the treatment of tumors as well as for detoxication. Tubeimoside I (TBMS I) is one of the main active ingredients of TBMS, the mechanism of action of which remains unknown. Human serum albumin (HSA) is the most abundant carrier protein in blood circulation. Three-dimensional (3D) fluorescence spectra and the excitation-emission matrix of interaction between TBMS I and HSA were measured at different temperatures. The results showed that HSA fluorescence was quenched by TBMS I through a static quenching mechanism. Also, the HSA fluorescence was quenched with the temperature increase from 283 K to 353 K. 3D spectral results revealed the changes in the secondary structure of HSA upon interaction with TBMS I. [ABSTRACT FROM AUTHOR]

Primary liver cancer is one of the highest mortality malignant tumors in the world. China is a high occurrence area of primary liver cancer. Diagnosis of liver cancer, especially early diagnosis, is essential for improving patients' survival. Light scattering and measuring method is an emerging technology developed in recent decades, which has attracted a large number of biomedical researchers due to its advantages, such as fast, simple, high accuracy, good repeatability, and non-destructive. The hypothesis of this project is that there may be some different light scattering information between hepatoma cells and hepatocyte. Combined with the advantages of the dynamic light scattering method and the biological cytology, an experimental scheme to measure the light scattering information of cells was formulated. Hepatoma cells and hepatic cells were irradiated by a semiconductor laser (532 nm). And the Brookhaven BI-200SM wide-angle light scattering device and temperature control apparatus were adopted. The light scattering information of hepatoma cells and hepatic cells in vitro within the 15°C to 30°C temperature range was processed by a BI-9000AT digital autocorrelator. The following points were found: (a) the scattering intensities of human hepatic cells and hepatoma cells are nearly not affected by the temperature factor, and the former is always greater than the latter and (b) the relaxation time of hepatoma cells is longer than that of hepatic cells, and both the relaxation time are shortened with increasing temperature from 15°C to 25°C. It can be concluded that hepatoma cells could absorb more incident light than hepatic cells. The reason may be that there exists more protein and nucleic acid in cancerous cells than normal cells. Furthermore, based on the length relaxation time, a conclusion can be inferred that the Brownian movement of cancer cells is greater. [ABSTRACT FROM AUTHOR]

A novel 24/17-pole 3-phase stator wound field flux switching (SWFFS) machine with the combination of overlapping armature winding (OAW) and asymmetric stator poles (ASP) is proposed for higher torque density in this article. First, the air-gap modulation principle of the 24/17-pole OAW-SWFFS machine is analyzed to better understand its torque production mechanism. Second, since the torque capacity will be greatly restricted by the serious magnetic saturation which is introduced by the OAW configuration, two effective measures are proposed from two perspectives in this article to solve this problem. The first measure is to reduce the magnetic saturation directly by optimizing the area ratio of armature slot and excitation slot, and thus, the torque density can be improved effectively. The second measure is to further enhance the open circuit flux linkages, back electromotive force (EMF), and thus, the torque density by adopting the proposed ASP structure. Furthermore, the accurate ASP distances which are corresponding to the largest back EMF can be obtained effectively based on the air-gap field modulation theory. Finally, the proposed design is validated experimentally by a prototype machine. The simulated and experimental results show that about 25.7% higher torque density can be obtained when compared with 24/14-pole SWFFS machine. [ABSTRACT FROM AUTHOR]

This study introduces an innovative method for identifying high-efficiency perovskite materials using an asymmetric convolution block (ACB). Our approach involves preprocessing extensive data on perovskite oxide materials and developing a precise predictive model. This system is designed to accurately predict key properties such as band gap and stability, thereby eliminating the reliance on traditional feature importance filtering. It exhibited outstanding performance, achieving an accuracy of 96.8% and a recall of 0.998 in classification tasks, and a coefficient of determination (R2) value of 0.993 with a mean squared error (MSE) of 0.004 in regression tasks. Notably, DyCoO3 and YVO3 were identified as promising candidates for photovoltaic applications due to their optimal band gaps. This efficient and precise method significantly advances the development of advanced materials for solar cells, providing a robust framework for rapid material screening. [ABSTRACT FROM AUTHOR]

Multimodal Federated Learning (MMFL) is a novel machine learning technique that enhances the capabilities of traditional Federated Learning (FL) to support collaborative training of local models using data available in various modalities. With the generation and storage of a vast amount of multimodal data from the internet, sensors, and mobile devices, as well as the rapid iteration of artificial intelligence models, the demand for multimodal models is growing rapidly. While FL has been widely studied in the past few years, most of the existing research was based in unimodal settings. With the hope of inspiring more applications and research within the MMFL paradigm, we conduct a comprehensive review of the progress and challenges in various aspects of state-of-the-art MMFL. Specifically, we analyze the research motivation for MMFL, propose a new classification method of existing research, discuss the available datasets and application scenarios, and put forward perspectives on the opportunities and challenges faced by MMFL. [ABSTRACT FROM AUTHOR]

Acrylamide (AA), an odorless and colorless organic small-molecule compound found generally in thermally processed foods, possesses potential carcinogenic, neurotoxic, reproductive, and developmental toxicity. Compared with conventional methods for AA detection, bio/chemical sensors have attracted much interest in recent years owing to their reliability, sensitivity, selectivity, convenience, and low cost. This paper provides a comprehensive review of bio/chemical sensors utilized for the detection of AA over the past decade. Specifically, the content is concluded and systematically organized from the perspective of the sensing mechanism, state of selectivity, linear range, detection limits, and robustness. Subsequently, an analysis of the strengths and limitations of diverse analytical technologies ensues, contributing to a thorough discussion about the potential developments in point-of-care (POC) for AA detection in thermally processed foods at the conclusion of this review. [ABSTRACT FROM AUTHOR]

The general rules of rotor pole and armature winding configurations combinations for 24-slot stator wound field flux switching machines (SWFFSMs) are investigated thoroughly in this article. Meanwhile, based on the virtual coil method, a novel general auxiliary evaluation variable, which is proportional to the fundamental amplitude of open-circuit flux-linkage of armature coil is proposed in this article. Hence, these SWFFSMs with larger open-circuit flux-linkage and back-EMF can be obtained effectively. In addition, the effect of rotor poles on the complementarity of armature windings is analyzed so that more sinusoidal and symmetrical back-EMF can be acquired. Furthermore, for these SWFFSMs with larger open-circuit back-EMF, the torque capability is restricted to a considerable extent due to the deep magnetic saturation caused by overlapping armature winding. Hence, a new method by optimizing the ratio of armature slot area and excitation slot area is proposed in this article to ensure that the higher torque density of selected SWFFSMs can be maintained. To verify the validity of analysis and methodology proposed in this article, seven representative SWFFSMs are chosen for verification at no load by the finite-element analysis (FEA) while a 24s/17p SWFFSM with the highest torque density is chosen for further verification at on-load conditions by the FEA and experiments. [ABSTRACT FROM AUTHOR]

The traditional direct toque control (TDTC) for induction motors (IM) is afflicted by large torque ripple, high current total harmonic distortion (THD), and variable switching frequency. Recently, some improved direct torque control (DTC) methods have been proposed to address the above problems, but they often suffer from obscure concept, intensive computation, and poor robustness. To further improve the performance, this article proposes a DTC method based on minimum voltage vector (VV) error. The proposed strategy effectively optimizes the duty ratio of fundamental VV to minimize the error between reference VV and final VV imposed on motor terminals. The optimization algorithm dose not increase the system's complexity much and can be intuitively understood by a graphical interpretation. Experiment comparisons between the proposed strategy and some existing DTC methods are conducted on a 0.55-kW IM platform. The proposed DTC method has proven to achieve better steady-state performance, while retaining fast dynamic response of TDTC. Furthermore, the proposed method can obtain almost constant average switching frequency in the entire speed range, especially with rated load, due to the utilization of proportional-integral type torque regulator. [ABSTRACT FROM AUTHOR]

In this paper, we introduce the topological entropy of a free semigroup action generated by proper maps, which extends the notions of the topological entropy of the free semigroup actions defined by Bufetov in 1999 and topological entropy of the proper maps defined by Patrão in 2010. We then give some properties of these notions and discuss the relations between them. We also give a partial variational principle for locally compact separable metric spaces. Moreover, the relationship between topological entropy of the free semigroup generated by proper maps and topological entropy of a skew-product transformation is given. These results extend the results obtained by Patrão, Bufetov and Lin, Ma and Wang in 2018. [ABSTRACT FROM AUTHOR]

As the third gasotransmitter, hydrogen sulfide (H2S) is involved in a variety of physiological and pathological processes wherein abnormal levels of H2S indicate various diseases. Therefore, an efficient and reliable monitoring of H2S concentration in organisms and living cells is of great significance. Of diverse detection technologies, electrochemical sensors possess the unique advantages of miniaturization, fast detection, and high sensitivity, while the fluorescent and colorimetric ones exhibit exclusive visualization. All these chemical sensors are expected to be leveraged for H2S detection in organisms and living cells, thus offering promising options for wearable devices. In this paper, the chemical sensors used to detect H2S in the last 10 years are reviewed based on the different properties (metal affinity, reducibility, and nucleophilicity) of H2S, simultaneously summarizing the detection materials, methods, linear range, detection limits, selectivity, etc. Meanwhile, the existing problems of such sensors and possible solutions are put forward. This review indicates that these types of chemical sensors competently serve as specific, accurate, highly selective, and sensitive sensor platforms for H2S detection in organisms and living cells. [ABSTRACT FROM AUTHOR]

Binary spinel Co 3 O 4 thin films with smooth surface were fabricated by using chemical solution deposition method and unipolar resistive switching characteristics including set and reset switching voltages, low and high resistance ratio, cycling endurance, and retention time were investigated in the Pt/Co 3 O 4 /Pt sandwich structures. Through the analysis of conductive mechanism and temperature dependence of resistance states, it was suggested that Ohmic conduction behavior governed the carriers transport in low resistance state and Schottky emission dominated the conduction mechanism in high resistance state, respectively. Moreover, the switching mechanism was explained by the formation and rupture of conductive filament during the set and reset processes. This study suggests that the solution-processed spinel Co 3 O 4 thin films could find potential application in nonvolatile resistive switching memory. [ABSTRACT FROM AUTHOR]

Conventional affinity biosensor typically relies on passive diffusion of analytes for binding reaction, which in many cases leads to long response time and lack of sensitivity. Recent research showed that directed particle motion towards sensor electrodes could be induced in sample matrix by applying a non-uniform AC electric field, often with AC dielectrophoresis as the responsible mechanism. As a result, shorter assay time and higher sensitivity can be achieved. Previously, we demonstrated a rapid and sensitive AC capacitive affinity sensor, which integrates low voltage AC dielectrophoresis into label-free capacitive measurement to achieve a single-step operation without any wash steps for clinical samples. However, dielectrophoretic force is rather short-ranged, and is also proportional to the size of target biomolecules/particles. Therefore, to detect target molecule at diluted concentrations or small molecule, improvement in sensitivity by dielectrophoresis could be quite limited. Alternatively, AC electric field can also produce microfluidic movement to carry biomolecules to sensors, which is of long range and size independent. This work demonstrates the use of low voltage AC electrothermal effect to enhance and accelerate the detection of low abundance and small target molecules by AC capacitive sensing with simultaneous AC electrokinetic enrichment. Electrode designs were studied for their effectiveness in AC electrothermal capacitive sensing. Electrodes with larger characteristic length were found to be more amenable to inducing AC electrothermal convection and were successfully used to detect low abundance protein and femto-molar level small molecules. [ABSTRACT FROM AUTHOR]

We extend the notion the topological entropy of a free semigroup action defined by Bufetov [6] to the case of a free semigroup action on a metric space not necessarily compact, provide some properties of this extended topological entropy, extend the topological analogue of the classical Abramov–Rokhlin formula for the entropy of a skew product transformations with respect to a metric space not necessarily compact and give some bounds for the entropy for some particular systems such as a free semigroup with m generators of affine transformations on p -dimensional torus and smooth maps on a Riemannian manifold. [ABSTRACT FROM AUTHOR]

In the healthcare field, cross-institutional collaboration can fasten medical research progress. Vertical federated learning (VFL) addresses data heterogeneity across multiple medical institutions while ensuring medical data privacy, thereby enhancing the accuracy of disease diagnoses and treatments. However, traditional VFL only benefits from aligned samples, thereby limiting its applicability due to constrained sample sizes, and a large amount of non-aligned data remains untapped, resulting in wasted data. To exert full leverage on the value of all data obtained from medical institutions, this paper proposes a federated healthcare collaborative framework based on semi-supervised representation augmentation mechanism with cross-institutional knowledge transfer (CrossKT-FRA). Specifically, the developed method comprises three steps. First, the federated representations of shared data (aligned data) among medical institutions are extracted through efficient vertical federated representation learning (FRL) methods. Second, the federated knowledge contained in federated representations and potential labels derived through recurrent learning assist local shared data representations in performing supervised augmented learning. Finally, the federated knowledge is transferred indirectly from the representation augmentation module for shared data to the unsupervised representation augmentation module for local private data (non-aligned data). The experimental results show the effectiveness of the proposed knowledge transfer mechanism, whether applied independently or used to enhance VFL on medical datasets. Our findings contribute to a deeper theoretical understanding of VFL, further facilitating the utilization of high-value medical data. By promoting cross-institutional and cross-disciplinary collaboration in healthcare data sharing, our study enhances the quality efficiency of medical services, thereby accelerating the development of interdisciplinary medical research. Code is available at https://github.com/LieLieLieLieLie/CrossKT-FRA. [ABSTRACT FROM AUTHOR]

[Display omitted] • An innovative two-stage machine learning framework (TMLF) was proposed. • The uncertainties of material and geometrics were considered. • The strengths of the RHS-CHS T-joint follow the gamma distribution. • ANN model shows the highest accuracy in predicting the RHS-CHS T-joints' strength. • The TMLF can accurately predict the distribution of structural component strength. Machine learning technics have been extensively used in the strength prediction of structural components in recent years, nevertheless, these established strength prediction models usually can not address the inherent uncertainties introduced by the material and geometrics of structural components. This paper intends to propose an innovative two-stage machine learning framework for developing probabilistic strength prediction models of structural components with the consideration of uncertainties of material and geometrics based on limited test results. Rectangular hollow section to circular hollow section (RHS-CHS) T-joints are used as an example for evaluating the proposed framework. To this end, 58,744 training and 19,870 validation datasets are first generated through numerical simulation. Three machine learning algorithms are used and evaluated in this paper to develop the best model for predicting the strength of the RHS-CHS T-joints. The analysis results show that the artificial neural networks (ANN) showed the best generalization performance. The combination of the uncertainties of material and geometrics is considered through the Latin hypercube sampling method. Then, a new strength database considering the randomness of the structural parameters (e.g., material and geometrics) are developed through the trained ANN model and the probabilistic distribution of the strength of the RHS-CHS T-joints is analyzed through the Anderson-Darling test method. The analysis results indicate that the random strengths of the RHS-CHS T-joints follow a gamma distribution while the material and geometrics follow the normal distribution. Finally, the machine learning models for probabilistic strength prediction of the RHS-CHS T-joints are developed and validated. The analysis results indicate that the developed machine learning model can accurately capture the distribution of the strength of RHS-CHS T-joints, confirming the efficiency of the proposed two-stage machine learning framework for developing probabilistic strength prediction models of structural components. A software named "Probabilistic strength prediction of RHS-CHS T-joint" is proposed based on the developed probabilistic strength prediction model for practical application. [ABSTRACT FROM AUTHOR]

Active disturbance rejection control using extended state observer (ESO) is less dependent on the knowledge of the system. It has proved to be an excellent scheme for speed control of electrical drives. However, for time-varying disturbance, the observation precision of conventional ESO is undesired, which limits the speed tracking accuracy. Accordingly, this article proposes an enhanced speed controller for electrical drives based on adaptive switching high-order ESO (ASHESO). First, the critical parameters affecting the steady-state performance of ASHESO are determined according to frequency analytical results. Then, optimized observer gain is obtained by modifying a part of pole locations, which weakens the influence of noise on estimated state. Finally, an adaptive switching gain mechanism is proposed according to the closed-loop tracking error and the swiftness of dynamic response is maintained. The proposed speed controller has achieved high estimation accuracy for disturbance and strong immunity to measurement noise. The feasibility and effectiveness of the strategy is verified on a laboratory permanent magnet synchronous motor (PMSM) drive system. [ABSTRACT FROM AUTHOR]

In this article, we present a dual-stator structure-parallel fault-tolerant machine (DSSPFTM). In this machine, the radial-flux dual-stator structure with a higher density is adopted to the fault-tolerant system. For better performance in fault condition, the combination of permanent-magnet component (PMC) and reluctance component (RC) in the rotor and large-opening slot is proposed. Because of the same poles and torque-variation principle, the PMC and RC are combined. The PMC is devised to supply most of the torque in normal conditions, while the RC provides enough self-inductance for limiting current under short-circuit (SC) occasion. Most of the flux leakage is separated from the active flux and the overload ability is improved. The design process of DSSPFTM is described in steps and details. Based on the fundamental of maximum torque under normal conditions, PMC and RC are integrated together. The end flux leakage originating from the adjacency of RC to PMC and the effect of RC length on torque are analyzed. The back-EMF, torque, inductance, loss, efficiency, and SC analysis are demonstrated. The stress and deformation distribution of the rotor and the comparison with the traditional structure are conducted. A prototype DSSPFTM is designed and manufactured. The experiments accord with simulations, indicating that the DSSPFTM with fault tolerance can improve the torque density effectively. [ABSTRACT FROM AUTHOR]

This article presents the optimal design of a dual-stator permanent magnet fault-tolerant machine (DSPMFTM). In order to enhance the torque density, the radial-flux dual-stator structure is expanded to redundant situation. The parallel rotor is proposed to add self-inductance for realizing limited short-circuit current, and thus, the deep and narrow notches (DNNs) are replaced with large-opening slots. The optimal design of DSPMFTM is raised in this article because of the more complexity of flux coming from the short distance between the reluctance part (RP) and the permanent magnet part (PMP). The influences of slot opening, separating distance between PMP and RP along with permanent-magnet shape, are considered. Also, the varieties of torque density, ratio of mutual inductance to self-inductance, and short-circuit current to rated value are examined. A prototype is designed and manufactured according to the optimization results. The experimental results are coincident with the simulations, indicating that the DSPMFTM has a better performance in torque density and fault tolerance. [ABSTRACT FROM AUTHOR]

For achieving high speed and large thrust, Langevin-type ultrasonic motors (LTUM) are generally operated under high voltage. However, high voltage causes the current harmonics of piezoelectric material nonlinear phenomena, which will decrease the efficiency, the output force, and the accuracy of LTUMs. In this study, the nonlinearity of current harmonics of LTUM are described and analyzed by a novel nonlinear equivalent circuit model using Lagrange equations. Thereafter, based on a nonlinear tuning method, a specific driver circuit is suggested to suppress the current harmonics. Experimental results validate that the time response of the current is consistent with that of the model and furtherly demonstrate that the total harmonic current distortion decreases by 68% utilizing the proposed nonlinear tuning method under 500 Vpp. • A nonlinear dynamic model and simple identification method of a Langevin-type ultrasonic motor are proposed to describe the current harmonics. • A nonlinear tuning method and drive circuit are developed to suppress current harmonics under high voltage. • Experiment results demonstrate that the time response of the current was consistent with that of the model. [ABSTRACT FROM AUTHOR]

Dual stator-winding induction generator (DWIG) is attractive in stand-alone power systems, and the aim of this paper is to develop the dc generating system of five-phase DWIG with an open phase. First, the relationship between flux and torque is constructed based on the reduced-order transformation, modified flux, and current. Second, the relation between modified voltage and current on the dq plane is constructed. The current of fundamental plane is used for the control loop of the power-winding voltage and control-winding voltage, respectively. Third, the current of the modified secondary subspace plane is used to control the five-phase DWIG operation at minimum control-winding loss. Finally, the simulation and experimental results are given to verify that the amplitude of phase current and output voltage can be regulated effectively by the proposed control strategy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nf-MSCF exhibits a remarkable piezocatalysis efficiency of removing 98% of RhB in 4 min under ultrasound. • Nafion layer of Nf-MSCF greatly enhanced the structural stability under sonication. • Nafion layer of Nf-MSCF enhanced adsorption of cationic organic substrates. • The removal mechanism for RhB of Nf-MSCF was proposed. • The piezoelectric voltage was simulated by COMSOL Multiphysics and measured in the experiment. The piezocatalytic effect is a promising approach for the efficient degradation of organic pollutants. However, directly dispersing such catalysts in aqueous media introduces other issues including media purification (since it constitutes a secondary pollutant), and catalyst recyclability. In this work, a highly recyclable hierarchical composite material, MoS 2 decorated onto carbon felt with further coated by Nafion (Nf-MSCF), was demonstrated to be an efficient piezocatalyst for organic pollutants degradation. The hierarchical Nf-MSCF catalyst structure designed in this way exhibited strong piezocatalytic performance as well as stability and durability. It achieved a high efficiency of removing 98% of Rhodamine B (RhB) pollutants in water after 4 min under ultrasound and this efficiency was maintained even after 300 min of ultrasound. Such excellent properties were attributed to the combined effects of high piezocatalytic activity of MoS 2 nanosheets, high specific surface area of carbon felt, and improved cation adsorption as well as stability resulting from surface modification by the Nafion layer. The reactive oxygen species generated was verified and analyzed by electron spin resonance measurements and radical trapping experiments. The Zeta potentials were measured to confirm the more negatively charged surface brought about by Nafion modification. Finally, combining COMSOL Multiphysics simulation and piezoelectric voltage measurement with energy band theory, the possible piezocatalytic mechanism of the structure was proposed. This work provides a facile strategy to prepare recyclable and high efficiency piezocatalysts, and further promotes the practical applications of piezocatalysis. [ABSTRACT FROM AUTHOR]

Electric vehicles enjoy not only vigorous promotion in many countries via green license plates but also state subsidies. This study investigates a traditional combustion-vehicle market and the coexistence of combustion and electric vehicles under the influence of network effects. It evaluates the impact of the greenness gap and network effect on their pricing, subsidies, and market returns, respectively. We then consider the conditions for introducing electric vehicles into the market. The results show that when the network effect is not considered, introducing electric vehicles is beneficial to customers, manufacturer and society. However, when the network effect is considered, introducing electric vehicles can increase manufacturer's profit and social welfare only when the fixed costs of the new product line are sufficiently low. Finally, electric vehicles should be introduced if the greenness gap between the two products is small because this can increase profit, consumer surplus, and social welfare. • The impact of network effects on introducing electric vehicles is studied. • Introducing electric vehicles benefits the manufacturer without network effects. • Introducing electric vehicles might harm the manufacturer with network effects. [ABSTRACT FROM AUTHOR]

A sensitive and efficient method for microRNAs (miRNAs) detection is strongly desired by clinicians and, in recent years, the search for such a method has drawn much attention. There has been significant interest in using miRNA as biomarkers for multiple diseases and conditions in clinical diagnostics. Presently, most miRNA detection methods suffer from drawbacks, e.g., low sensitivity, long assay time, expensive equipment, trained personnel, or unsuitability for point-of-care. New methodologies are needed to overcome these limitations to allow rapid, sensitive, low-cost, easy-to-use, and portable methods for miRNA detection at the point of care. In this work, to overcome these shortcomings, we integrated capacitive sensing and alternating current electrokinetic effects to detect specific miRNA-16b molecules, as a model, with the limit of detection reaching 1.0 femto molar (fM) levels. The specificity of the sensor was verified by testing miRNA-25, which has the same length as miRNA-16b. The sensor we developed demonstrated significant improvements in sensitivity, response time and cost over other miRNA detection methods, and has application potential at point-of-care. [ABSTRACT FROM AUTHOR]