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Introduction/AimThe purpose of this study is to investigate the key predictors of online learning system continuance intention using expectation-confirmation theory and information system success model as the theoretical framework.MethodsA total of 537 respondents participated in the questionnaire to measure their self-reported responses to eight constructs (perceived usefulness, interaction, confirmation, satisfaction, continuance intention, information quality, system quality, service quality). Convenience sampling was used to obtain participants in this study. Partial least square structural equation model is used for data analysis.ResultsThe results showed that all the hypotheses were validated except that there was no significant positive relationship between online learning interaction and student satisfaction. Meanwhile, the variance of the continuance intention of the online learning system reached 74.0%, falling within the moderate to substantial. In addition, the multi-group analysis of perceived usefulness, satisfaction and continuance intention showed that there was no significant gender difference in the above two relationships.DiscussionFinally, this study also puts forward the theoretical and practical implications of college students’ continuance intention of online learning system.

Additional file 1. hPAEPIC activity at different concentrations of LPS was detected by cell counting kit 8 (CCK-8) assay.

BackgroundAtopic diseases and atrial fibrillation (AF) seem to share an underlying inflammatory pathology. To date, some population-based studies have explored the relationship between the two. We aimed to conduct a meta-analysis to examine the role of atopic condition in AF risk.MethodsAll relevant observational studies in PubMed and EMBASE databases up to November 2021 were searched. In RevMan 5.3, we used random-effects or fixed-effects models to pool the effect sizes of hazard ratio (HR), odds ratio (OR) and their corresponding 95% confidence intervals (95% CI). In addition, I2 and Cochran Q test were used to evaluate the heterogeneity.ResultsA total of 2488 records were retrieved. After screening according to the predetermined criteria, 6 cohort studies and 2 case-control studies were included in this meta-analysis. Herein, the meta-analysis of 6 cohort studies suggested that atopic diseases potentially increased the AF risk with the pooled HR of 1.26 (95%CI,1.14–1.39), while the pooled effect size (OR, 1.04; 95%CI,0.74–1.46) of 2 case-control studies was not statistically significant. Based on the types of atopic diseases, further subgroup analyses of 6 cohort studies revealed that asthma, allergic rhinitis, and atopic dermatitis all potentially increased the risk of subsequent AF with the pooled HR of 1.41 (n = 4; 95%CI, 1.25–1.58), 1.12 (n = 1; 95%CI,1.10–1.14) and 1.06 (n = 3; 95%CI, 1.01–1.12), respectively.ConclusionThis meta-analysis demonstrated that patients with atopic diseases have a higher risk of developing AF, particularly those with asthma.

In this study, 2D/3D TiO2/ZnIn2S4 nanostructures with TiO2 sheet cluster embedded into ZnIn2S4 micro flowers were fabricated via hydrothermal method. The matched band structure, the enlarged surface area and the efficient photo-induced charge transfer offered by effective heterostructures formed between the two components endowed the TiO2/ZnIn2S4 nanoarchitecture with excellent photocatalytic Cr(VI) reduction and tetracycline hydrochloride (TC) degradation performance. Especially, the Cr(VI) photoreduction efficiency of 50% TiO2/ZnIn2S4 was 8.8 times higher compared to pure ZnIn2S4. The enhanced separation efficiency of photo-excited charge carriers was induced by the matched band structure, the enlarged surface area and the strong interaction between TiO2 and ZnIn2S4. The key roles of ·O2− was confirmed via trapping experiments. Otherwise, the pathway of TC degradation was investigated. The proposed mechanism during photocatalysis process was also discussed according to the photocatalytic and characterization results.

The conventional triaxial loading in gas seepage studies does not reflect the actual stressing state in the coal seam. Thus, a true triaxial seepage experimental apparatus is developed before seepage tests are conducted with it. The first group of tests is carried out with continuous axial loading under uniform lateral constrain on moulded coal specimen: one test under constant-velocity axial loading, two tests under monotonic variable-velocity axial loading, and two tests under single-cycle variable-velocity axial loading. The tests reflect the multi-step, discontinuous, stressing condition with variable-loading rate and strength in a coal seam. The law of coal deformation and gas permeability variation under constant-velocity and variable-velocity axial loading is obtained. Then, the multi-step seepage tests under different non-uniform lateral pressures are conducted, focusing on permeability variation under different triaxial stresses versus gas pressure and intermediate principal stress. The permeability increase with gas pressure decrease is confirmed and interpreted. Moreover, the turning point between Klinkenberg effect and gas wedging effect in the coal seam is determined. A simplified concept of average effective stress is put forward, and the dominant influence of this average effective stress on coal seam permeability is identified based on the concept.

WS2-based nanomaterials have been extensively studied due to their unique catalytic properties. However, it is still a great challenge to prepare WS2-based electrocatalysts with both maximally active edge sites exposure and high electronic conductivity. In this work, we have engineered a 1D–2D multidimensional nanostructured TiO2 nanorod@carbon layer supported flower-like WS2 nanosheets (TNRs@C@WS2) electrocatalyst with abundant exposed active edge sites as well as high electron transfer abilities. The TNRs@C@WS2 was explored as a good catalyst for the triiodide reduction reaction. The assembled dye-sensitized solar cell achieves a high photoelectric conversion efficiency (7.15%) and comparable to that (7.18%) of Pt. This unique 1D–2D multidimensional nanostructure may open up new opportunities for a variety of applications in clean energy and catalysis.

Supplementary Material 1

In this study, Z-scheme Zn doped Fe2O3/ZnIn2S4 (Zn-Fe2O3/ZnIn2S4) heterojunction with improved spatial charge separation ability was successfully fabricated through solvothermal method. The obtained samples exhibited improved photocatalytic degradation performance containing ciprofloxacin (CIP) as simulated pollutant. The excellent photoactivity could be attributed to the tight contact between Zn-Fe2O3 nanocubes and ZnIn2S4 microflowers to form the interfaces which is convenient for charge transfer. Otherwise, the matched band gap structure of Zn-Fe2O3 and ZnIn2S4 could be the driving force of effective separation and transfer of photo-excited electron-hole pairs. The study of the photocatalytic mechanism demonstrates that the charge transfer path on Zn-Fe2O3/ZnIn2S4 architectures conforms to the Z-scheme route. We hope this research could provide new ideas for the feasible design of Z-scheme heterojunction with high-performance in the field of photocatalysis.

The bimetallic hydroxide NixCo1-x(OH)2 was first prepared through hydrothermal method. The prepared NixCo1-x(OH)2 architecture showed good photocatalytic degradation performance toward oxytetracycline (OTC), especially the Ni0.25Co0.75(OH)2 hierarchical microflowers. After deposition of Ag nanoparticles, Ag/Ni0.25Co0.75(OH)2 nanocomposites with further improved photocatalytic activity were obtained especially on 0.2% Ag/Ni0.25Co0.75(OH)2. The modified band structure with optimal loading amount of Ag nanoparticles was convinced to have positive effect on the efficient photo-induced charge separation and transfer during photocatalytic procedure. This study expanded the application of hydroxides in the field of photocatalysis, and provided ideas for the construction of new photocatalytic system.

Ag/ZnFe2O4 nanoarchitectures composed of ZnFe2O4 nanoparticles loading onto Ag nanowires were fabricated by hydrothermal method. The Ag/ZnFe2O4 nanocomposites possessed excellent performance in simulated photocatalytic wastewater treatment like sulfanilamide (SAM) photodegradation and Cr6+ photoreduction. The improvement of photoactivity could be ascribed to the successful formation of Schottky interface between ZnFe2O4 nanoparticles and Ag nanowires and the enhanced light absorption ability in visible light region with modified energy band structures, which make further efforts to the ameliorate separation and improved mobility of photo-induced charge carriers with enhanced performance in photocatalysis. The Ag/ZnFe2O4 nanocomposites exhibited outstanding photoactivity than single component and more importantly, the unique magnetic properties enabled the Ag/ZnFe2O4 photocatalysts to be recycled easily with the aid of external magnetic field, which make it possible for practical applications.

In order to explore the evolution law of stress and strain in the process of hydraulic fracturing, a hollow inclusions stress-strain gauge was used for monitoring. The results show that the influence range of high-pressure water spreads to the monitoring borehole at 47m after 2 hours of hydraulic fracturing, and its influence on the stress-strain monitoring point reaches the maximum, and the strain tends to be stable in the later stage. After 6 days of hydraulic fracturing, the strain returns to a stable state without any change, but it is still larger than the state before hydraulic fracturing. During hydraulic fracturing, the increment of principal stress increases, but the amplitude is different. Hydraulic fracturing mainly affects the increment of vertical stress, which is related to the stress-strain monitoring point and the space location of the hydraulic fracturing borehole. After hydraulic fracturing, the stress increment decreases gradually and tends to return to the original stable state due to the gradual pressure relief of fracturing fluid, but it is still larger than the state without hydraulic fracturing. Hydraulic fracturing has little effect on the azimuth and dip angle of coal and rock mass. The stress-strain law can provide reference for the exploration of the coal seam permeability increasing mechanism of hydraulic fracturing.

A hydrophilic interaction liquid chromatography (HILIC)&ndash, ultra high-pressure liquid chromatography (UHPLC) coupled with tandem mass spectrometry (MS/MS) method was developed and applied to profile metabolite changes in human Huh-7 cells exposed to the potent aryl hydrocarbon receptor (AHR) ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Comparisons of sensitivity (limit of detection as low as 0.01 &micro, M) and reproducibility (84% of compounds had an interday relative standard deviation (RSD) less than 10.0%, 83% of compounds had an intraday RSD less than 15.0%) were assessed for all the metabolites. The exposure of Huh-7 cells to the hepatotoxic carcinogen TCDD at low doses (1 nM and 10 nM for 4 h and 24 h, respectively) was reflected by the disturbance of amino acid metabolism, energy metabolism (glycolysis, TCA cycle), and nucleic acid metabolism. TCDD caused a significant decrease in amino acids such as serine, alanine, and proline while promoting an increase in arginine levels with 24 h treatment. Energy metabolism intermediates such as phosphoenolpyruvate and acetyl&ndash, CoA and nucleosides such as UMP, XMP, and CMP were also markedly decreased. These results support the application of HILIC&ndash, UHPLC&ndash, MS/MS for robust and reliable analysis of the cellular response to environmentally relevant toxicants at lower doses.

The purpose of algorithm selection is to automatically select the most suitable one for the current problem from among the many available optimization algorithms. For this problem, this paper describes the recommendation algorithm selection of meta-learning. Firstly, the related techniques based on meta-learning are analyzed. Then the algorithm selection framework and the extraction of meta-features are constructed. Finally, the problems of algorithm selection based on meta-learning ideas are proposed, and the future development direction is pointed out.

Manganese-based cathodes for aqueous rechargeable zinc ion batteries (ZIBS) are attracting extensive attention owing to high energy density, high safety of mild aqueous electrolyte, environmental friendly, facile battery assembly and low cost of sources materials. Here, a new manganese-based battery system for aqueous ZIBs by employed orthorhombic manganese silicate (Mn2SiO4) as cathode, Zn metal as anode, mild aqueous ZnSO4 + MnSO4 as electrolyte is reported for the first time. The Zn/Mn2SiO4 battery shows good Zn storage performance and can deliver reversible capacity of 154 mA h g−1 in the first cycle. Notably, the battery undergoes capacity deterioration in initial cycles, but exhibits superior cyclic stability after several cycles. A comprehensive study reveals the electrochemical reaction mechanism of this battery system is the irreversible phase transition from Mn2SiO4 to amorphous todorokite MnO2, amorphous SiO2 and crystalline phase occurs during the first charge, and followed by reversible conversion reaction between amorphous phase (todorokite MnO2 and SiO2) and crystalline phase (MnOOH, ZnxMnO2 and Zn2SiO4) in the subsequent cycles. Although the practical capacity and reaction mechanism needs to be clearly evaluated, this work could provide new insights into exploiting other advanced cathodes for aqueous rechargeable ZIBS.

Ultrathin C3N5 nanosheets with enhanced photocatalytic methylene blue (MB) degradation and H2-evolution performance were prepared from thermal treatment of 3-amino-1,2,4-triazole (3-AT) and NH4Cl followed with a protonate procedure. The characterization results revealed that the protonating process could contribute to the exfoliation of C3N5 with large surface area, the effective charge transfer capability and the modified band structure. The as-prepared C3N5 nanosheets exhibited enhanced properties in photocatalytic reactions such as MB photodegradation and H2-evolution from water splitting. This study offered a feasible route to prepare highly-efficient two-dimensional photocatalyst, which could be applied potentially for implementation in wide range of energy generation and environmental applications.

This paper presents a programmable in-memory-computing processor, demonstrated in a 65nm CMOS technology. For data-centric workloads, such as deep neural networks, data movement often dominates when implemented with today's computing architectures. This has motivated spatial architectures, where the arrangement of data-storage and compute hardware is distributed and explicitly aligned to the computation dataflow, most notably for matrix-vector multiplication. In-memory computing is a spatial architecture where processing elements correspond to dense bit cells, providing local storage and compute, typically employing analog operation. Though this raises the potential for high energy efficiency and throughput, analog operation has significantly limited robustness, scale, and programmability. This paper describes a 590kb in-memory-computing accelerator integrated in a programmable processor architecture, by exploiting recent approaches to charge-domain in-memory computing. The architecture takes the approach of tight coupling with an embedded CPU, through accelerator interfaces enabling integration in the standard processor memory space. Additionally, a near-memory-computing datapath both enables diverse computations locally, to address operations required across applications, and enables bit-precision scalability for matrix/input-vector elements, through a bit-parallel/bit-serial (BP/BS) scheme. Chip measurements show an energy efficiency of 152/297 1b-TOPS/W and throughput of 4.7/1.9 1b-TOPS (scaling linearly with the matrix/input-vector element precisions) at VDD of 1.2/0.85V. Neural network demonstrations with 1-b/4-b weights and activations for CIFAR-10 classification consume 5.3/105.2 $\mu$J/image at 176/23 fps, with accuracy at the level of digital/software implementation (89.3/92.4 $\%$ accuracy).

Coal mine roadway advanced detector, including the transmitting and receiving devices, is a kind of geophysical instrument used in coal mine roadway advanced detection based on the dynamic and directional electric field excitation method. The transmitting device emits dual frequency modulated square wave current into the excavation face and the receiving device receives potential difference of coal and rock medium generated by induced polarization, of which the frequency selection circuit is to filter the interference of the harmonics of the signal and other frequency components. The paper derived expressions of emission current. Considering the actual working conditions, the paper proposed the design requirements of the frequency selection circuit and the scheme of a controller to control multiple frequency selection filter circuits. The paper completed the design of the control circuit consisting of a microcontroller and analog switch MAX313 and the band-pass filter circuit consisting of universal active filter UAF42. According to the circuit simulation and the analysis of the data with software of multisim, it proves the design of circuit meets the requirements.

The dynamic and electric field excitation method is a new advanced detection method. In this method, the observation frequency and of emission electrode must be reasonably selected according to the actual geological conditions of coal mine roadway to obtain the apparent frequency with adequate Induced Polarization (IP) information of geological anomalies and improve the measurement accuracy of the instrument. This paper completed the simulation of apparent frequency varying with the observation frequency and Cole-Cole model parameters with MATLAB software. The results show that the key to selecting the observation frequency mainly depends on the charge and discharge time constant .Then the paper analyzed the effect of the measured apparent frequency on the measurement accuracy. According to time constant values​​ of geological conditions in coal mine roadway, considering the efficiency and electromagnetic coupling effects on the measurement, it is best to select the observation frequency within a frequency range of 0.05~0.1Hz and the frequency ratio coefficient of 13 or 15. Now apparent IP effect is obtained.

An implementation of an instrument of magnetic measurement for steel structures is presentedin this paper. Apply a Hall element probe as a transducer to detect the damaged parts of steel structure. The damage will cause a magnetic variation which can be indicated as a voltage variation of Hall sensor's output when the steel structure is magnetized. After a series of data processing include of pretreatment, amplification, conversion and communication, the PC will get the voltage variation of the sensor and displayit incurve forms, these curves can reflect the damaged parts of the steel structure.Laboratory experiments prove the validity and practicability of this instrument.

The dual-frequency Induced Polarization method (IP method for short) has been widely used for the detection of ground and tunnel. Affected by strong noise environment in coal roadway, it is very difficult to accurately detect underground weak IP signals. For the promotion in the field of advanced detection in underground coal mine, it is of great significance to research weak excitation signals detection mechanism of the receiver used in the coal mine. On the basis of principle prototype developed, the paper derived theoretically the data processing method of weak IP signals and the detection mechanism of IP parameters and designed a RC (Resistance-Capacitance) network test platform and mathematical calculation model. Through comparing the fitting curve between experiment and theoretical calculation of apparent frequency and apparent relative phase difference about the model, the results show that the measuring precision of phase is higher than that of amplitude about the receiver of principle prototype. The principle prototype of mine dual-frequency IP instrument receiver needs to be further improved and perfected in the aspect of amplitude measurement.

This paper has firstly designed a type of flexible finger based on the bidirectional active bending joint we have developed before; then we regard the finger as the actuator, and do the flexible clamping force experiments on the finger with loading the air pressure using the idea of the master-slave control based on computer; consequently, we acquire the influence on impact force under different control strategies, which is valuable for the dynamic analysis and motion accuracy control of the flexible robot hand.

A novel machining method using the Electrorheological(ER) fluid which contains fine abrasives as the polishing medium has been presented to polish tungsten carbide die. In ER fluid-assisted polishing process, the machining principle is the ER effect generated by ER fluid which rheological properties and microstructure will be readily changed when the electric field is applied. In the present work, the distribution of the electric field strength on the surface of workpiece was analyzed through ANSYS and theoretical equation. Moreover, the attractive force acting on particles that disperses in ER polishing fluid was calculated. A series of basic experiments were conducted, it is aimed to find out the effective process parameters on the surface roughness using the workpiece as electrode.

This paper presents the design of a computer aided testing system aimed to the vane pump performance test, in which sensors and the PCI cards are at the bottom layer, the computer is the core of the control system, VC++ is the platform for software designing. In this design, the loading mode is used with proportional valve, PID control method and PWM technology service the temperature control, speed adjustment adopts the frequency inversion technique. Therefore, it finally realizes computer aided testing of the vane pump performance test.

Design and analysis on the new type of Pneumatic Artificial Muscle (PAM) with elongation and torsion is presented. The PAM we developed can not only elongate but also twist about its axis when supplied the air pressure. We establish the theoretical models of axial elongation using strain-energy function; analyze the twist performance applying the Moore integral; discuss the influences of wire diameter, active coils and helix angle of spring on the elongation and torsion angle. The Experimental data verified the theoretical model which provides a theoretical basis to make the flexible rotary joint and robot hand using this type PMA.

To satisfy the need of hardware-in-the-loop simulation of infrared imaging sensor, a method of dynamic infrared scene generation based on infrared modeling is proposed. Infrared scene generation is divided into three parts, including infrared calculation, infrared scene 3D modeling and program and code for relation simulation. Multigen Creator and Vega are used as a high performance software environment and toolkit. The computer infrared scene displays a dynamic black-white scene that has a flying target in it with different grey levels stand for different infrared radiation levels.

Because of the importance of falling liquid films in engineering applications such as evaporators, chemical reactors, condensers, turbine blades, etc., film flow and related problems have received considerable attention. Great augmentation in heat transfer can be expected for a vertical wall being wetted by a liquid film. So, a large body of literature was presented or published on the topic of transport characteristics of falling liquid film flow, especially in the last two decades. Chu and Dukler 1 , 2 measured instantaneous thickness related to wavy liquid film flow in the situation of Re > 700. They stressed the random characteristics of film thickness variation with time and presented meaningful statistical analyses. They interpreted their data in terms of two main classes of random waves, i.e., large waves which carry a significant portion of all flowing liquid and small waves which cover the substrate that exists between large waves. They concluded that, the small wave structure controls the fluid resistance and transfer process in the gas while the large waves control these same processes in the liquid film. Recently, instantaneous film thickness and other parameters were studied experimentally for Re ranging from 30 to 5000 3 , 4 , 5 , or studied numerically 6 , 7 , 8 , 9 . Several conclusions were reached as follows