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Ultra high frequency (UHF) partial discharge (PD) detection is a common method for transformer oil-paper insulation defect location. However, the accuracy of PD positioning in practical application is easily affected by noise and sensor layout. In order to ensure the effectiveness of PD positioning detection of transformer oil-paper insulation defect, an UHF PD positioning detection platform for oil-paper insulation defects is established. Based on the conventional K-means method, a modified clustering demarcation PD anti-interference positioning method is proposed, which effectively reduces the positioning error. Aiming at the problem of sample clustering demarcation aliasing, when the optimal correction coefficient L is 1.1, the UHF PD positioning error can be reduced to less than 0.1 m, which verifies the effectiveness of the proposed method. Finally, the variation law of positioning error of different sensor layout is analyzed, and the optimal layout scheme of UHF sensor for transformer oil-paper insulation defect detection is proposed, which can provide reference for the layout and positioning of transformer on-line monitoring sensor.

BackgroundIn recent years, the rising number of e-cigarette users among adolescents and the surging cases of lung injury related to e-cigarette use have attracted the attention of researchers in various fields.ObjectiveTo identify the research hotspots and trends of e-cigarette or vaping product use associated lung injury (EVALI) worldwide from 2013 to 2022 by bibliometric and visual analysis. MethodsWeb of Science Core Collection was selected to obtain literature related to EVALI from 2013 to 2022 across the world, statistics were calculated by country/region, institution, author, journal, cited literature, keyword, etc. CiteSpace 6.2.R1 was used for visual analysis to draw diagrams of publication trend, author cooperation network, co-citation clustering time distribution, and keyword cluster. ResultsA total of 888 EVALI-related papers published between 2013 and 2022 were retrieved. The number of publications was gradually increased, with a significant increase in 2020 and a decrease from 2021, but the number of citations was increased year by year. The most active country was the United States (631 articles). European and American countries cooperated closely and the centrality was prominent. Among the publishing institutions, the University of California system topped the list with 103 articles. Rahman I (27 articles) published the most articles and had a high degree of centrality; Goniewicz M L was the most cited author; and the network analysis diagram showed relatively weak collaboration between authors. The American Journal of Respiratory and Critical Care Medicine was the journal with the highest number of publications (94 articles). The top 5 cited articles were all cited more than 300 times. The leading high-frequency keywords of EVALI-related studies were nicotine (149 times), exposure (118 times), and oxidative stress (80 times). The cluster of key nodes in the co-citation network and the clustering time distribution diagram indicated youth e-cigarette addiction received widespread attention from society. From the top 25 keywords with the strongest bursts, the focus of research on the pathogenesis of EVALI gradually shifted from the oxidative stress damage associated with e-cigarette vapor to the oxidative effect of flavoring chemicals in the process of lung injury. The current research interests in this field were mainly the mechanisms of various chemicals in e-cigarettes and the heating elements that led to damage to the lungs. ConclusionEVALI is receiving continuous attention from researchers in government, medical institutions, and other organizations. A variety of e-cigarette ingredients such as flavoring chemicals may lead to varying degrees of cytotoxicity, inflammation, and lung damage. However, the pathophysiology of EVALI remains unclear. In the future, more Chinese scholars should be encouraged to participate in this field.

The insulation performance of transformer bushings is a crucial aspect that directly affects the safe operation of equipment. To diagnose the insulation status of transformer bushings and mitigate the impact of small-sample imbalanced data on diagnostic results, a particle swarm optimization combined with back propagation neural network (PSO-BPNN) and adaptive synthetic sampling (ADASYN) method are employed to fault diagnosis of transformer bushing. Initially, historical fault data of transformer bushings are gathered, and a sample set of dissolved gases in transformer oil with distinct fault categories is established. The ADASYN algorithm is used to synthesize the minority class samples in the original data, which allowed for obtaining balanced fault data. The balanced dissolved gases in oil served as the model input, and the fault status is used as the label output to diagnose the transformer bushings using the PSO-BPNN model. To diagnose the bushings under the original sample set, the back propagation neural network (BPNN), genetic combined with back propagation neural network (G-BPNN), cuckoo search combined with back propagation neural network (CS-BPNN), and PSO-BPNN models are used. The results reveal that the PSO-BPNN model based on ADASYN balanced data exhibited the highest accuracy among the various models for fault diagnosing the insulation status of transformer bushings. This approach effectively mitigate the impact of small sample imbalanced data on diagnostic results, and provide an effective method for assessing the insulation performance of transformer bushings.

A new method was proposed for point-of-care testing (POCT) of immunosuppressants in blood using thin-layer paper spray ionization and a miniature mass spectrometer. The aluminum thin-layer plate was used as paper spray substrate, and cut into an equilateral triangle. Aliquots of 10 μL blood sample were loaded on the aluminum thin-layer plate, and then 20 μL methanol was dropped as elution/spray solvent. The tip of the triangular plate was placed 1.0 cm in front of the discontinuous atmospheric pressure interface (DAPI) of the miniature mass spectrometer. When the spray voltage was applied, the sample was eluted from the triangular plate and formed paper spray ionization at the tip. Coupled with the miniature mass spectrometer, five immunosuppressants were detected under negative ion mode. The precursor ions ［M-H］- of tacrolimus, sirolimus, everolimus, ciclosporin A, and mycophenolic acid are m/z 802.6, 912.6, 957.1, 1 200.8, 319.1, and product ions are m/z 560.2 and 604.3, m/z 590.3 and 321.2, m/z 590.3 and 365.2, m/z 1 088.8, m/z 287.4 and 275.1, respectively. Based on the observed signal-to-noise ratio (S/N) of the most intense tandem mass spectrometry (MS/MS) fragment peaks and using the S/N=3 and 10 as the criteria, the limits of detection (LODs) and quantitation (LOQs) are estimated to be 0.5-5 mg/L and 1-10 mg/L, respectively. The internal standard method was used for quantitative analysis, and indapamide was used as the internal standard compound. Sufficient linearity for each analyte is obtained with the correlation coefficients (r) greater than 0.99. The proposed method displays good recoveries in the range of 91.0%-114.3% with the relative standard deviations (RSDs) less than 8.4%. Moreover, the developed method was used for the analysis of blood samples, which spiked with tacrolimus, sirolimus, everolimus, cyclosporine A and mycophenolic acid at the concentration of 100 mg/L. The analytical results demonstrated the consistency between the proposed method and the traditional liquid chromatography-mass spectrometry (LC-MS) method. The entire analysis procedure can be completed within 1 min. The proposed method is simple, fast, accurate, efficient, and suitable for POCT of immunosuppressants in blood.

Based on the selective quenching effect of the flavonoid rutin on the fluorescence of carbon dots prepared by asparagine pyrolysis, a method for rapid detection of rutin content in the flower buds of Sophora japonica by using chitosan-based carbon dot paper chip was developed. A filter paper was immersed in the casting solution of carbon dots and chitosan. After drying, a carbon dot chitosan film was formed on the surface of the filter paper, so that the chitosan-based carbon dot paper chip was obtained. After samples were dripped on the chip, chromogenic reaction occurred uniformly within a limited region, and pictures were taken under an ultraviolet (UV) lamp at 365 nm for analysis of the red (R), green (G), and blue (B) values of the colored spots in order to optimize the preparation conditions and detection conditions. The results showed that the optimal conditions were as follows: chitosan concentration of 20 mg/mL, carbon spot concentration of 1.0 mg/mL, 50% ethanol as sample solvent, and reaction time of 20 min. Under these conditions, the difference (ΔG) in G-value between sample and solvent spots had a linear relationship with rutin concentration (C) in the range of 4 to 120 mg/mL. Using this method, the average contents of rutin in the flower buds of S. japonica from three batches were determined to be 23.85%, 22.83% and 20.30%, the average relative standard deviations (RSDs) were 6.1%, 5.6% and 6.7%, and the recoveries were 91.27% to 107.5%, which were close to the results of high performance liquid chromatography (HPLC). The proposed method is simple and rapid, and can be used for rapid on-site determination of rutin content in the flower buds of S. japonica.

Results of academic research require publication and need to be reviewed by peers before they can contribute to the existing body of knowledge. Among the various means of publishing research findings, researchers may, according to past academic practices, first present their research results in conferences, seminars or symposiums, and then submit their results to journals for publication. Hence, the issue of “extended publication”, where conference papers are revised and submitted to journals, has gained attention in the library and information science community. This study collected public documents on the Internet and applied document analysis to examine the ethical considerations regarding such extension practice. First, this research reviewed the basic principles of research integrity and responsible behavior. Secondly, this research listed several types of violation related to research paper writing and submission, and studied the guidelines established by both domestic and foreign academic organizations, publishers, and journals. The findings of the research were used to provide specific recommendations on the best practices for extending conference papers to journal articles.

To explore the microscopic mechanism of thermal stability of oil-paper insulation， a molecular model consistent with the actual oil-paper insulation is established. Through comparison with the experimental results， the effectiveness of the model is verified. With temperature as an independent variable， variation of the mechanical parameters and hydrogen bond energy of the cellulose molecular model under the action of a thermal field is investigated. The results show that parameters characterizing the mechanical properties of cellulose， such as bulk modulus （K）， Young's modulus （E）， shear modulus （G）， and Poisson's ratio （v） of the cellulose crystalline zone model are larger than those of the amorphous zone model at the same temperature， and the distribution of hydrogen bond energy remains the same. Thus， the cellulose crystalline zone is superior to the amorphous zone in mechanical properties and determines the insulation properties of cellulose insulating paper. The results of the study provide a theoretical basis and method for investigating the microscopic mechanism of thermal aging of oil-paper insulation.

[Purpose/Significance] Interdisciplinary research can creatively solve complex problems in natural environment and human society through knowledge integration and penetration. With the increase of interdisciplinary research results, the evaluation of interdisciplinarity becomes increasingly necessary. How to establish an effective method for interdisciplinarity measurement and achieve a comprehensive measurement of scientific research papers is an urgent problem to be solved. [Method/Process] Based on the above background, this study takes the data of scientific research papers as the analysis source, deconstructs the interdisciplinarity of scientific research papers from multiple dimensions, constructs the feature set of interdisciplinarity of scientific research papers, and on this basis proposes the method for measuring interdisciplinarity based on the adaptive method of machine learning, and conducts a comprehensive measurement of interdisciplinarity. This study has certain positive significance for researchers to understand the interdisciplinary papers in the field. The work process is as follows: First of all, the basic concepts of interdisciplinarity are sorted out and related concepts are discriminated, and the index of interdisciplinarity of different dimensions is analyzed. Based on the connotation and characteristics of interdisciplinary research, the characteristic index of interdisciplinarity of scientific research papers is extracted from three dimensions: subject attribute, knowledge network topology and knowledge integration text content. Secondly, an interdisciplinarity measurement method based on machine learning is constructed. By analyzing information gain and feature similarity of input indexes and data in feature sets, a feature selection calculation method based on adaptive feature selection is proposed, and the accuracy of feature classification is maximized by machine learning classifier. At the same time, the feature subset that can best express the interdisciplinary is selected based on the adaptive selection of the minimum number of features, and the selected adaptive feature set is used in the calculation of the interdisciplinary of the paper, and the results of the calculation of the original feature set are analyzed comprehensively. Finally, an empirical study was carried out in the field of plant nanobiotechnology to verify the effectiveness of the index system and adaptive feature selection listed above, identify and screen papers with high interdisciplinarity in the field, measure the interdisciplinarity of papers and identify key influencing factors based on the calculation of subject attributes, knowledge network topology and knowledge integration text content features. [Results/Conclusions] The main empirical results show that, among the subject attributes, the balance degree and the difference degree have a greater effect on the interdisciplinary evaluation. The overall effect of knowledge network topology structure features is satisfactory, the distribution breadth of knowledge integration text content features has a greater effect on interdisciplinary evaluation, and the calculation effect is further improved by fitness weighted summation of each feature. The results demonstrate that the adaptive feature selection proposed in this paper can effectively screen the interdisciplinary related feature indexes, improve the reliability of the results, and achieve a comprehensive and in-depth measurement of the interdisciplinary of scientific research papers. This measure method avoids the subjective defects that may occur in qualitative evaluation and the problems that different measure indicators may produce contradictory results. It provides a new idea and direction for interdisciplinary measurement.

New paper-based microfluidic technology has been widely used in many fields due to their advantages such as easy preparation, low cost, and non-toxic environmental protection, compared with the shortcomings of other food analysis and detection techniques such as complex production method and high cost of preparation. The outline of new paper-based microfluidic technology is briefly summarized and the probes including organic molecules, nanomaterials and polymers their structural activity with regard to sensing performances along with their limit of detection are also discussed. This review is expected to assist readers for better understanding of the sensing mechanisms of various chemo and bio-probes utilized in µPADs, as well as promote their advancement in the field. The detection mechanism and its advantages in the whole detection system at the same time to get the ideal experimental results of new paper-based microfluidic technology in the food analysis of pesticide residues, pathogenic bacteria, additives, heavy metals and other substances are mainly introduced. This study would provide the theoretical basis and references for fast detection field. The future challenges and application prospects of this technology are prospected.

“Lab on paper” is a paper-based microanalytical system with unique advantages such as high sensitivity, low cost, portability, and mass production, which breaks through the limitations of traditional detection technologies and shows great potential in the field of rapid on-site food detection. In this paper, the typical “labs on paper”, including chromatographic paper, chemical test chip, lateral flow assay (LFA), microfluidic paper-based analytical devices (μPADs), and synthetic biological paper, are systematically reviewed. Special emphasis is put on the application of “lab on paper” in the field of food detection. Finally, the advantages, challenges, and future prospects of paper-based analytic methods are discussed, which may provide theoretical support for better application of “lab on paper” in the field of food detection.