bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive sequential reclosing strategy for hybrid HVDC circuit breakers in MMC‐based DC grids
Authors: Yu Jingqiu , Zhang Zheren , Xu Zheng
Published: March 2022

DC circuit breaker (DCCB) is one of the most promising solutions for handling DC fault in half‐bridge modular multilevel converter (MMC)‐based DC grid. Generally after fault isolation, DCCBs are required to have the ability to quickly reclose so as to restore power transmission. However, the traditional simultaneous reclosing scheme may make the whole system suffer from secondary strikes such as overvoltage and overcurrent in the event of permanent faults. To solve this problem, many adaptive reclosing schemes have been proposed. Among them, the sequential reclosing scheme can achieve rapid recovery without laying any burden on the sampling and protection system. Unfortunately, secondary strikes under a reclosing failure still exist though they can be suppressed. Due to this, this paper illustrates that the overcurrent protection‐based fault identification method is not able to identify the fault in time, and thus the secondary strikes are generated during the second tripping. Optimal configuration of DCCBs' parameters can reduce these adverse impacts but cannot avoid them. Based on this, an adaptive reclosing scheme is proposed. Permanent and temporary faults are recognised according to the voltage characteristics at the beginning of the fault line as soon as the arresters are conducted. Extensive simulations on a four‐terminal DC grid in PSCAD/EMTDC show that the proposed method can eliminate the potential adverse impacts and is robust to fault resistance.
Generalized frequency estimator with rational combination of three spectrum lines
Authors: Gigleux Benjamin , Vincent François , Chaumette Eric
Published: March 2022

The popular Discrete Fourier Transform (DFT) is known to be a sub‐optimal frequency estimation technique for a finite transform length. In order to approach the Cramer‐Rao Lower Bound (CRLB), many refinement techniques have been considered, but little considering both zero padding or tapering, also known as windowing or apodisation. In this paper, a frequency estimator with closed‐form combination of three DFT samples is generalized to zero padding and tapered data within the class of cosine windowing. Root Mean Squared Error (RMSE) is shown to approach the CRLB in the case of a single tone signal with additive white Gaussian noise. Compared to state‐of‐the‐art techniques, the proposed algorithm improves the frequency RMSE up to 1 dB when using significant zero‐padding lengths (K ≥ 2 N) and for small to moderate SNR, which is the most challenging case for practical radar applications.
Prosumer‐centric energy storage system and high voltage distribution network topology Co‐optimisation for urban grid congestion management
Authors: Zhang Xi , Liu Youbo , Zeng Yu , Wu Gang , Liu Junyong
Published: March 2022

The surge of electricity load and the growing number of renewable energy sources (RESs) in urban power grid result in severe and frequent congestion for transmission networks. This causes the transmission system operators (TSOs) perform the high voltage distribution network (HVDN) reconfiguration frequently. The frequent reconfiguration of the HVDN will cause the fast degradation of high voltage circuit breakers, high maintenance and operational cost, and stability problems. To reduce the frequency of HVDN reconfiguration, this paper proposes a prosumer‐centric energy storage system (ESS) and HVDN topology co‐optimisation for transmission congestion management. Numerical results show that with the assist of ESS operational strategy, the reconfiguration frequency of HVDN can be significantly reduced while mitigating the transmission congestion.
Non-invasive leakage detection & localisation technique in noisy industrial environment
Authors: Efstathiadis Theofilos , Kalfas Anestis , Kousiopoulos Georgios P. , Papastavrou Georgios N. , Nikolaidis Spiros
Published: March 2022

An innovative non-invasive method for pipe leak detection and localization in noisy environment is presented in this paper. Nowadays, it is well known that complex pipeline networks are used for operational purposes and fluid transportation in every high-end-technology heavy industry such as refineries, combined heat and power cycles, cement and steel industries, etc. In all these cases, safety is the key parameter in order to ensure the efficient plant operation and to avoid any possible accident with devastating consequences that may lead to a turn down of the production process. For this reason, it is mandatory to develop reliable enough methods for detection of fluid leakages which represent the most common threaten in pipeline networks. Towards to this direction an integrated experimental setup was built in order to validate the results of the algorithm which was also developed for the purposes of the present study and aims to detect and locate the artificial leakages through the attenuation of the acoustic signal propagating in a pipeline. This experimental setup consists of pipelines that installed into an anechoic chamber and uses pure water as working medium. Apart from the high-efficient accuracy of the developed algorithm in the leakage detection and localization, the proposed method was designed with extra focus on the reduced CAPEX and OPEX costs. Finally, according to the results the proposed system gives sufficiently low false alarm regarding the leakage detection, while the mean percentage error of the leakage localization is around 6% which is considered as an acceptable value.
Retraction Note: Axial-torsional fatigue and cyclic deformation of 304L stainless steel at room temperature
Authors: Bemfica Cainã , Mamiya Edgar , Castro Fábio
Published: March 2022

This paper has been formally retracted on ethical grounds because it is not an original article. Indeed, it has already been partially published in another journal. Request approved by the proceedings Editor and the Publisher on February 28, 2022.
Themes of climate change agency: a qualitative study on how people construct agency in relation to climate change
Authors: Toivonen Heidi
Published: March 2022

This study analyzes how people discursively construct their (non)agency—how they display abilities and capacities to act, or the lack thereof—vis-à-vis climate change. The paper presents the results of a detailed discursive and thematic analysis of 28 interview transcripts: 12 broad agency themes representing different ways of constructing human (non)agency in relation to climate change. The most common agency theme was Collective, followed by Individual, Critical, and Threatened agency. Climate change skepticism was displayed mostly within Critical agency, where the speakers presented themselves as intellectual and critically thinking individuals, drawing from scientific rhetoric while criticizing and misrepresenting climate science. The constructions of Collective agency emerged as a form of agency that displays a sense of meaningfulness related to socially embedded actions. The construction of agency in relation to climate change is very detailed discursive work, as people draw from multiple societal discourses to craft varied discursive positions of experiencing, knowing, and doing in relation to it. The paper suggests ways for climate communications to take into account these multiple themes of agency.
Risk factors and missing persons: advancing an understanding of ‘risk’
Authors: Ferguson Lorna
Published: March 2022

This study seeks to advance an understanding of ‘risk’ for persons going missing—a phenomenon also known as missingness. There is a need to clarify terms used to describe correlations or statistical associations between variables that are identified as risk factors for missing person incidents to understand the mechanisms influencing this phenomenon. Without such research, policies and preventative strategies cannot be adequately offered to begin to reduce missingness. To do so, a review is first provided of the current risk factors identified internationally for missing persons. Then, the Kraemer and colleagues (Arch Gen Psychiatry 54:337–343, 1997; Kraemer et al., Am J Psychiatry 158:848–856, 2001) risk factor classification system and MacArthur framework are applied to the risk factors to identify the ways in which these may be overlapping, proxy, mediating, and/or moderating factors. This clarification on risk terminology attempts to offer a common language for communicating about risk factors associated with missing persons. Suggestions are then provided for how these factors may overlap and/or work together to form risk pathways. The application of this framework highlights that ‘going missing’ may have multiple risk pathways that transgress the current risk factor categorical boundaries. The article then concludes that consistent use of terms and additional research on risk factors will enhance investigations of missing persons and understandings of low- and high-risk groups.
Proximity-field nanopatterning for high-performance chemical and mechanical sensor applications based on 3D nanostructures
Authors: Lee Jinho , Cho Donghwi , Chen Haomin , Shim Young-Seok , Park Junyong , Jeon Seokwoo
Published: March 2022

In this era of the Internet of Things, the development of innovative sensors has rapidly accelerated with that of nanotechnology to accommodate various demands for smart applications. The practical use of three-dimensional (3D) nanostructured materials breaks several limitations of conventional sensors, including the large surface-to-volume ratio, precisely tunable pore size and porosity, and efficient signal transduction of 3D geometries. This review provides an in-depth discussion on recent advances in chemical and mechanical sensors based on 3D nanostructures, which are rationally designed and manufactured by advanced 3D nanofabrication techniques that consider structural factors (e.g., porosity, periodicity, and connectivity). In particular, we focus on a proximity-field nanopatterning technique that specializes in the production of periodic porous 3D nanostructures that satisfy the structural properties universally required to improve the performance of various sensor systems. State-of-the-art demonstrations of high-performance sensor devices such as supersensitive gas sensors and wearable strain sensors realized through designed 3D nanostructures are summarized. Finally, challenges and outlooks related to nanostructures and nanofabrication for the practical application of 3D nanostructure-based sensor systems are proposed.
A novel all-metal metamaterial for constructing relativistic slow wave structure
Authors: He Yufang , Kong Xiangtian , He Juntao , Ling Junpu , Pi Mingyao
Published: March 2022

In recent vacuum electronic devices, metamaterials have shown an obvious advantage of miniaturization. Due to increasing miniaturization demand, research of metamaterials in high-power microwave (HPM) field is now also a hotspot. For better applications of metamaterials, there are still two issues to be solved, the low space limit current of the structure and the low uniformity of the working electric field. To solve these problems, we construct a novel all-metal metamaterial structure by applying a 45° rotational arrangement in space and a four-support rod structure. This new metamaterial structure has a great uniformity of the axis electric field, and its electric field fluctuation is reduced from 8.6% to 2.8%. Based on this metamaterial structure, we proposed a novel relativistic slow wave structure, and its working mode has a negative dispersion characteristic. Using the method of expanding the electron beam channel, the space limit current of the relativistic slow wave structure is greatly improved to 12.3 kA, and the particle simulation method is used to prove the increase in the space limit current. In addition, it is found that this slow wave structure has higher coupling impedance, which provides a better working environment for an annular relativistic electron beam. Therefore, this metamaterial structure has great potential in the HPM field.
Investigation of optical density in photonic quasicrystals for filtering applications: Effect of composite layers
Authors: Daneshfar Nader , Shahrabadi Saeed
Published: March 2022

The optical density in one-dimensional (1D) photonic quasicrystals, such as the symmetric alternating sequence, Thue–Morse sequence, Fibonacci sequence, double-periodic sequence, and Cantor sequence, is investigated in the framework of the transfer matrix method. In order to describe and measure the transmission of light through a photonic quasicrystal, we will study the optical density, which is an important physical property for designing optical filters and can be used to tune the operational wavelength of optical filters and sensors. The effect of composite layers consisting of small inclusion particles (metal fillers) embedded in a host medium on the optical density is shown and discussed by using the Maxwell Garnett effective medium approximation. The influence of the volume filling fraction of metal nanoparticles on the optical density spectrum of photonic quasicrystals and their spectral characteristics is demonstrated. In other words, we discuss the impact of individual components and their fractions in the composite on the optical density and compare the optical density spectra for different 1D photonic quasicrystals.
A new divalent organoeuropium(II) fluoride and serendipitous discovery of an alkoxide complex from pentaphenylcyclopentadiene precursors
Authors: Shephard Angus C. G. , Delon Aymeric , Kelly Rory P. , Guo Zhifang , Chevreux Sylviane , Lemercier Gilles , Deacon Glen B. , Dushenko Galina A. , Jaroschik Florian , Junk Peter C.
Published: March 2022

From the redox-transmetallation protolysis (RTP) reaction of europium metal, Hg(C6F5)2 and pentaphenylcyclopentadiene, we isolated and crystallographically characterised small amounts of the first divalent europium fluoride half-sandwich complex [Eu(C5Ph5)(μ-F)(thf)2]2 (1). Subsequently, a rational synthesis of this complex from in situ formed [EuF2(thf)n] and [Eu(C5Ph5)2] was carried out. In addition, the new divalent Eu alkoxide complex [Eu(OC5Ph5*)2(thf)4] (2) (OC5Ph5* = 2,3,4,5,5 pentaphenylcyclopenta-1,3-dienolate) was identified by X-ray diffraction analysis, in which an intriguing phenyl group migration in the cyclopentadiene ligand occurred. This complex was shown to be derived from small impurities of 1,2,3,4,5-pentaphenylcyclopenta-1,3-dienol (C5Ph5OH) in the C5Ph5H starting material and was then synthesised on a larger scale. Density functional theory calculations provided evidence for the facile phenyl group migration observed in the cyclopentadienolate ring.
Stancetaking in Hong Kong political discourse
Authors: Liu Ming
Published: March 2022

This study gives a corpus-assisted discourse study (CADS) of stancetaking in the public speeches of three former Chief Executives. Three large corpora have been built by collecting all the public speeches of the three former Chief Executives. It combines automatic semantic tagging with the tripartite analysis of stancetaking in terms of evaluation, positioning and (dis)alignment. The findings not only reveal their preferential ways of stancetaking but also the changing socio-political contexts behind their particular ways of stancetaking. It is argued that a combination of the methods and theories in critical discourse analysis, stancetaking, and corpus linguistics can generate more illuminating findings concerning stancetaking in political discourse.
Multiculturalism in media representation
Authors: Zhang Dan
Published: March 2022

This study explores the issue of multiculturalism in China’s journalism practice through the analysis of news coverage on the Sino-US trade war inChina Daily(CD) and theSouth China Morning Post(SCMP). Following a corpus-based critical discourse analysis approach, the study compares thematic dimensions as well as recurring semantic patterns associated with them that denote two newspapers’ evaluative positioning. The findings reveal that CD’s reporting seems to be nationalistic-centric with overly positive representation of China’s practices and policies, while SCMP’s representation is multiculturalism-oriented with the representation of multiple discourses and articulation of competing and diversified viewpoints towards the evaluation of China’s market access and economic reform. The study concludes by recommending China’s official media practice continues to explore a multiculturalism approach to build dialogues with the international community in tandem with efforts made in promoting political, economic and cultural power.
Doing participatory fandom through trans‑scripting
Authors: Song Yang , Feng Yuhan
Published: March 2022

This article examines trans-scripting in transnational, multilingual fandom on Sina Weibo, the largest Chinese microblogging site. Taking one of the most popular Korean pop music (K-pop) bands named BTS as a case study, 741 instances of trans-scripting were manually selected from a total of 18,243 comments under the official Weibo account of the largest BTS fan club in China. Combining online observation and corpus-based analysis, our study draws on the notions of engaged audience and affinity space to reveal how multiple patterns of trans-scripting are heavily mobilized by K-pop fans in translingual idol naming, the transcultural maintenance of fan-idol kinship, and the intertextual confirmation of shared media consumption experiences. We argue that trans-scripting is an under-explored linguistic strategy used by transnational pop-culture fans, providing an analytical lens for research on fan identity and fan-communal membership. Theoretically, trans-scripting can serve as a useful lens to analyze networked multilingual fandom.
Rapport building by Chinese celebrities on Weibo and Facebook
Authors: Lin Minfen , Wu Doreen D.
Published: March 2022

The paper examines how Chinese celebrities build rapport with their followers on social media, with a comparison between the Chinese mainland (on Weibo) and Hong Kong (on Facebook) celebrities. Rapport building is conceptualized as language use in promoting social bonding and emotional involvement and as achieved via at least two aspects: use of relational acts and choice of interactional features. Twelve months of postings by twelve most-followed Weibo and Facebook celebrities from the Chinese mainland and Hong Kong in 2017 have been retrieved and analyzed. It is found that the prevalent relational acts commonly used by both Weibo and Facebook celebrities to build rapport with their followers include sharing information, retweeting information and directives, among others; and the commonly prevalent interactive features include the use of colloquialism, emoji & emoticons, and hashtags or @, and the like. Nonetheless, significant differences also exist in that while Weibo celebrities tend to use more acts of showing stance, Facebook celebrities use more acts of showing appreciation; Weibo celebrities tend to use more colloquialism, emoji & emoticons, and internet slang, Facebook celebrities tend to use more English codemixing and vernacular expressions. Finally, the paper concludes with a discussion and explanation of the commonalities and differences between Weibo and Facebook celebrities.
‘Suiran danshi’
Authors: Cheng Ruixin , Chen Xinren
Published: March 2022

‘Suiran danshi(‘although but’)’ used on Chinese social media is a novel variant of ‘suiran(‘although’)…danshi(‘but’)’, a typical pairing of adversative connectives in Mandarin Chinese. This article hypothesizes that ‘suiran danshi’ is a memetic expression resulting from pragmatic ellipsis and repeated use for special functions in the context of online communication. To verify this hypothesis, the authors collected data from Weibo and WeChat, two most widely used social media platforms in China, and analyzed the use of ‘suiran danshi’ in context. It is argued that as an elliptical form, ‘suiran danshi’ complies with the requirements of the Economy Principle and the Politeness Principle. As a meme, the emergence and popularity of the variant are ascribable to its special functions of teasing and facilitating social bonding, as well as to the vagueness of language use and the richness and complexity of cyber-context afforded by the Internet.
Microstructure and mechanical properties of friction stir welded high phosphorus weathering steel
Authors: Wang Yixun , Tsutsumi Seiichiro , Kawakubo Takumi , Fujii Hidetoshi
Published: March 2022

The mild steel with low phosphorus is vulnerable to corrosion while higher phosphorus often results in hot crack by fusion welding. The present study evaluated microstructures and mechanical properties of high phosphorus steels joined by friction stir welding below the A1 temperature. The microstructure was analysed considering various phosphorus contents, and mechanical properties were assessed by digital image correlation. The results suggest that alloying elements (nickel, chromium and niobium) contribute to the refinement of pearlite in the base metal and cementite in the stir zone. The increasing phosphorus improves the microhardness and strength of friction stir welded joints but weakens the ductile behaviour. The added alloying elements can enhance the ductile behaviour and mechanical strength at the same time.
Robust polarization gradient cooling of trapped ions
Authors: Li Wenbing , Wolf Sebastian , Klein Lukas , Budker Dmitry , Düllmann Christoph E , Schmidt-Kaler Ferdinand
Published: March 2022

We implement three-dimensional polarization gradient cooling (PGC) of trapped ions. Counter-propagating laser beams near 393 nm impinge in lin ⊥ lin configuration, at a frequency below the S1/2 to P3/2 resonance in 40Ca+. Our measurements demonstrate that cooling with laser beams detuned to lower frequencies from the resonance is robust against an elevated phonon occupation number and works continuously in the crossover from regular Doppler cooling to detunings of tens of linewidths. It is thus robust against heating events and also works well for an initial ion motion far out of the Lamb–Dicke regime. We show that PGC performance strongly depends on residual micromotion (MM) and find PGC working for a MM modulation index β ⩽ 0.1. Still, we find that the spectral impurity of the laser field affects both, cooling rates and cooling limits. Thus, a Fabry–Pérot cavity filter is employed to efficiently suppress amplified spontaneous emission of the diode laser. We demonstrate mean phonon numbers for a single ion of 5.4(4) at a trap frequency of 2π × 285 kHz and 3.3(4) at 2π × 480 kHz, in the axial and radial directions, respectively.
Measuring brain response to transcutaneous vagus nerve stimulation (tVNS) using simultaneous magnetoencephalography (MEG)
Authors: Keatch Charlotte , Lambert Elisabeth , Woods Will , Kameneva Tatiana
Published: March 2022

Objective. Transcutaneous vagus nerve stimulation (tVNS) is a form of non-invasive brain stimulation that delivers a sequence of electrical pulses to the auricular branch of the vagus nerve and is used increasingly in the treatment of a number of health conditions such as epilepsy and depression. Recent research has focused on the efficacy of tVNS to treat different medical conditions, but there is little conclusive evidence concerning the optimal stimulation parameters. There are relatively few studies that have combined tVNS with a neuroimaging modality, and none that have attempted simultaneous magnetoencephalography (MEG) and tVNS due to the presence of large stimulation artifacts produced by the electrical stimulation which are many orders of magnitude larger than underlying brain activity. Approach. The aim of this study is to investigate the utility of MEG to gain insight into the regions of the brain most strongly influenced by tVNS and how variation of the stimulation parameters can affect this response in healthy participants. Main results. We have successfully demonstrated that MEG can be used to measure brain response to tVNS. We have also shown that varying the stimulation frequency can lead to a difference in brain response, with the brain also responding in different anatomical regions depending on the frequency. Significance. The main contribution of this paper is to demonstrate the feasibility of simultaneous pulsed tVNS and MEG recording, allowing direct investigation of the changes in brain activity that result from different stimulation parameters. This may lead to the development of customised therapeutic approaches for the targeted treatment of different conditions.
An open-source transparent microelectrode array
Authors: Weaver Isaac A , Li Austin W , Shields Brenda C , Tadross Michael R
Published: March 2022

Objective. The micro-electrode array (MEA) is a cell-culture surface with integrated electrodes used for assays of electrically excitable cells and tissues. MEAs have been a workhorse in the study of neurons and myocytes, owing to the scalability and millisecond temporal resolution of the technology. However, traditional MEAs are opaque, precluding inverted microscope access to modern genetically encoded optical sensors and effectors. Approach. To address this gap, transparent MEAs have been developed. However, for many labs, transparent MEAs remain out of reach due to the cost of commercially available products, and the complexity of custom fabrication. Here, we describe an open-source transparent MEA based on the OpenEphys platform (Siegle et al 2017 J. Neural Eng.
14 045003). Main results. We demonstrate the performance of this transparent MEA in a multiplexed electrical and optogenetic assay of primary rat hippocampal neurons. Significance. This open-source transparent MEA and recording platform is designed to be accessible, requiring minimal microelectrode fabrication or circuit design experience. We include low-noise connectors for seamless integration with the Intan Technologies headstage, and a mechanically stable adaptor conforming to the 24-well plate footprint for compatibility with most inverted microscopes.
Criticality of the excess energy cost due to the unit-flux-quantum external field for the (2 + 1)D superfluid–insulator transition
Authors: Nishiyama Yoshihiro
Published: March 2022

The two-dimensional (2D) spin-S = 1 XY model was investigated numerically as a realization of the (2 + 1)D superfluid–Mott-insulator (SF–MI) transition. The interaction parameters are extended so as to suppress corrections to finite-size scaling. Thereby, the external field of a unit flux quantum (Φ = 2π) is applied to the 2D cluster by incorporating the phase factor

e

i

ϕ

i
j

(ϕ

ij
: gauge angle between the i and j sites) into the hopping amplitudes. Taking the advantage in that the exact-diagonalization method allows us to treat such a complex-valued matrix element, we evaluated the excess energy cost ΔE(2π) due to the magnetic flux Φ = 2π explicitly in the SF (XY) phase. As a result, we found that the amplitude ratio ρ
s/ΔE(2π) (ρ
s: spin stiffness) makes sense in proximity to the critical point, exhibiting a notable plateau in the SF-phase side. The plateau height is estimated, and compared to the related studies.
Some problems of protecting the rights of beneficiaries in the execution and termination of a grant agreement awarded by the European Commission
Authors: Slepak V
Published: March 2022

It is obvious now that the objective of strengthening scientific and technological bases is not only the goal of individual states but an objective of integration organisations as well. Europe produces a third of the world’s new knowledge, but creativity and dynamism in the field must be stimulated inter alia by financial means. For this purpose in 2021 Framework Programme Horizon Europe was launched. However there are still questions to be resolved by legal science and practice in order to clarify legal rules covering relations between parties to grant agreement concluded under EU law. Some of that matters deal with the rules governing the process of repayment of funds received by a Beneficiary from the European Commission under a grant agreement. In this paper the author analyses legal nature of documents issued by the Commission in order to get the financing back and requirements applicable to the content of such documents. The author studies possible arguments for and against qualification of Commission documents containing demands of the repayment as a legal acts of the EU institution challengeable under Article 263 Treaty on the Functioning of the European Union and analyses possible requirements to the content of such documents from the perspective of future court proceedings.
Mechanism of regulatory sandboxes for legal regulation of megascience class facilities operations
Authors: Balyakin A A , Nurakhov N N , Nurbina M V
Published: March 2022

The paper considers the features of the unique scientific facilities network that is being formed within the framework of the national project “Science”. Such projects are a complex enterprise that requires a specific management apparatus and appropriate information and legal support. The prospects of implementing the best practices in the activities of high-flux research nuclear reactor PIK are considered. In particular, the mechanism of protection of the created objects of intellectual property, possible ways of evaluation, examination and commercialization of the results of scientific research are discussed. The possibility of using the mechanism of regulatory sandboxes for specific financial products arising as a result of the activities of a megascience class installation (for example, a mechanism for insuring the results of production within the framework of experiments, a procedure for protecting intellectual rights) is discussed. It is shown that experimental legal regimes are widely used in world practice and are a catalyst for the development and implementation of innovations. It is proposed to focus not only on the experience of advanced countries (such as EU, and the USA), but also on the approaches of developing countries that are creating their own scientific infrastructure (Brazil, Argentina). Regulatory sandbox implementation proposals in the field of megascience facilities regulation are formulated. The idea of the need to create exclusively unique products and abandon all options for mass production is expressed, the latter involves considering megascience facilities as unique not only in the scientific sense, but also in the field of legal regulation.
A MegaScience class experimental complex at the University
Authors: Zadeba E A , Petrukhin A A
Published: March 2022

In the classification of the Ministry of Science and Higher Education in the National Project “Nauka” (2018), the concept of MegaScience is the name of a class of unique scientific installations, and in general terms, these are large expensive international scientific and research complexes for solution of actual scientific problems. It is emphasized that world-class breakthrough research is impossible within the framework of one university or organization, without attracting multi-billion budgets. However, the practice of MEPhI shows that it is possible to construct the unique scientific installations and to achieve results comparable to the largest international projects within a university in cooperation with other Russian and foreign organizations.
Improving the Funding of Megascience Projects under Current Budget Policy of Russia
Authors: Moshkova D M , Tkachenko R V
Published: March 2022

The article looks at the peculiarities of funding national projects and large-scale scientific projects as part of adoption of innovative economic model of the society’s development. In particular, funding of mega-science projects in Russia and abroad and its specifics has been studied. Particular examples of financial activities undertaken by the entities implementing mega-science projects like PIK and NICA have been provided. Ways to improve the funding of this sphere have been specified.
A Single Channel End-to-End Speech Enhancement using Complex Operations
Authors: Wu Jie , Liu Hongqing , Gan Lu , Zhou Yi
Published: March 2022

This paper investigates the possibility of using complex operations to perform speech enhancement task in time domain. To that end, first, the Hilbert transform is utilized to prepare the complex input in time domain. After that, the complex temporal convolutional network (CTCN) is developed to conduct complex convolutions. By cascading the TCN and the CTCN modules, the final proposed network form an encoder-decoder structure, which performs an end-to-end speech enhancement task. The results demonstrate that utilizing complex information in time domain indeed improves the enhancement performance. Compared to other approaches, the proposed network also demonstrates a superior performance in terms of objective evaluations.
Wireless Communication Strategy with BATS Codes for Butterfly Network
Authors: Wang Shiheng , Zhou Quan , Yang Siyuan , Bai Chaoyuan , Liu Heng
Published: March 2022

In this paper, two transmission schemes for batched sparse(BATS) codes based on a multicast protocol in a butterfly network are studied. For both of the schemes, a source file is first segmented into several packets at the source node, which are then coded with outer coder of the BATS codes to generate potentially unlimited batches. Rather than the linear network, in which the packets are directly transmitted to the next node, the packets will be forwarded to multiple nodes in the butterfly network. All the intermediate nodes which receive the packets recode them with random linear network coding (RLNC). At the destination node receivers, the sink node decodes the packets transmitted from different links. The Scheme I requires the intermediate nodes to recode the packets until all of them are received. On the contrary, the intermidate nodes of Scheme II just recode the packets as soon as receiving them and forward the recoded packets to the next node immediately. The Belief Propagation(BP) decoders of these two schemes are studied and applied to Scheme I and Scheme II respectively. The simulation results show that Scheme I consumed fewer batches than Scheme II, which indicates Scheme I outperforms Scheme II.
A Knowledge Base-based Method for Line Loss Abnormality Diagnosis in Station Area and Automatic Generation of Loss Reduction Measures
Authors: Ni Linna , Yao Li , Ding Qi , Zhang Jiangming
Published: March 2022

In view of the current low efficiency of line loss abnormality analysis and the inability to automatically generate loss reduction strategies, this paper proposes a knowledge base-based method for the abnormality diagnosis of line loss and automatic generation of loss reduction strategies. In this study, the research on line loss in station area at home and abroad is summarized, the classification of line loss abnormality is sorted out. Combined with the operation status of low-voltage distribution network and the current status of line loss, the intelligent diagnosis method of line loss abnormality is proposed and line loss reduction strategies is automatically generated according to the classification of line loss abnormality, which provide a decision-making support for improving the lean level of line loss control in the station area. Through application system development and display, the effectiveness of this method is verified.
Diagnosis of Interturn Short Circuit of Permanent Magnet Synchronous Motor Based on Stacked Normalized Sparse Autoencoder
Authors: Chen Yunfeng , Li Yuanjiang
Published: March 2022

Regarding the problems such as the traditional auto-encoders’ tendency to learn the similar features during the feature extraction and limited capability of feature learning in the shallow network models, the paper puts forward an interturn short circuit diagnosis method for Permanent Magnet Synchronous Motor (PMSM) based on the Stacked Normalized Sparse Autoencoder (SNSAE). The method is to guarantee the representativeness of the extracted features, acquire stronger anti-interference capability, and is more suitable for training diversified and large-capacity mechanical equipment failure data. Four types of Inter-Turn Short-Circuit (ITSC) fault data were collected on the PMSM fault diagnosis experimental platform for testing. The experimental outcome suggests that the SNSAE algorithm can effectively extract the fault features, and the fault diagnosis effect is better than the traditional intelligent diagnosis method, and its diagnosis accuracy is as high as 98.91%.
Analysis of the Impact of Substation Switching Operations on 5G Base Station Antenna Feeder Ports
Authors: Wang Zhihui , Liu Shulei , Zhang Ying , Hu Yue , Zhu Sicheng
Published: March 2022

With the rapid development of the construction and application of 5G communication networks in the power grid, more and more 5G base stations need to be built in substations. 5G base stations have antennas placed outside in a complex electromagnetic environment, and they also become sensitive ports that induce external electromagnetic interference while sending and receiving signals. Especially the Electrical Fast Transient/Burst generated during the switch operation in the substation through the cable connecting the antenna and the base station equipment, at the antenna feeder port, generates electromagnetic disturbance that poses a potential threat to the operation of the equipment. This paper proposes an analysis method of an electromagnetic disturbance at the antenna feeder port of a 5G base station under the condition of switching operation of a substation. A 500kV substation is used to calculate the impact size, and the minimum distance between the antenna of the 5G base station and the switch operation device is determined. When the distance between the cable and the ground is two meters, the cable disturbance voltage reaches the maximum.
Research on Multi Charging Path Planning for Network Layout
Authors: Huang Shan , Zuo Yahui , Liu Xiaolu
Published: March 2022

With the development of Internet of things, Rechargeable Wireless Sensor Network (WRSN) has been widely used. In order to keep the WRSN working, the mobile charger needs to be charged regularly. This paper studies the practical problems of WRSN charging. Aiming at the problem of path and battery capacity planning under complex constraints of multiple chargers, using the traditional MTSP model for reference, the minimum energy consumption path and battery capacity planning model under multiple chargers are established, and the equilibrium factor is creatively designed and applied. Considering the NP-hard characteristics of the problem, an improved genetic algorithm based on Balance degree is designed to solve it. Finally, four cases are tested and compared with the traditional genetic algorithm. The results show that the improved genetic algorithm saves 31.56% of the total distance on average compared with the traditional algorithm, and has better stability and better optimization ability. The results are reasonable and have wide application value.
An Automatic Marking Method Based on Object Detection Algorithm in Aerial Images
Authors: Ou Zuhao , Liu Changhua , Jiang Da
Published: March 2022

Aerial images of brassica napus in field were taken by UAV equipment but often contained unnecessary areas, which caused interferences and inconveniences to the subsequent study of identification of flowering stage by brassica napus images. To solve above problems, YOLO-V4 object detection algorithm based on Convolutional Neural Network (CNN) is adopted to build a model to detect brassica napus distribution area in aerial images, and model is trained iteratively by training data sets and setting initial parameters. As a result, the mean average precision (mAP) of the object detection model reached 96.24%, and the average loss is only 0.5843. In addition, the generalization and robustness ability of model have been evaluated by testing data sets. Conclusion shows the model proposed in this paper can indeed achieve an application of object detection and automatic labeling in aerial brassica napus images with a good performance.
A Computational Approach of Displacement Prediction in an Engineering Project
Authors: Tang Jonathan Chen , Peng Liang , Chen Zhenlei
Published: March 2022

In this paper, a fuzzy information granulation method combined with a support vector machine time series prediction model(FIG-SVM) is established for a subway cross passage project of Ningbo Metro Line 3. The FIG-SVM prediction model was used to predict the ground settlement of the subway access during the shield construction process. It was found that the FIG-SVM prediction model can effectively predict the ground settlement trend for the next construction stage based on the historical data of the ground settlement.
Design and Performance Analysis of Toothless Slip Type Magnetic Rotary Oil Well Pipe Tong
Authors: Zheng Jie , Bi Cheng , Lu Heng , Li Zhenzhen , Yang Xu , Yang Yushan , Lu Yuan , Dou Yihua , Zhang Yarong
Published: March 2022

Although the current hydraulic power pipe tong can improve efficiency and reduce strength, there are still some deficiencies. Among them, the inevitable defects are a low degree of automation, high labor intensity, complex mechanical mechanisms, and high maintenance costs. In order to improve its performance, the principle of permanent magnet motor is applied to the processing of shackle of oil pipe tong, and a new type of magnetic rotary oil pipe tong is proposed. The design eliminates the complex planetary gear train transmission mechanism and hydraulic circuit in the traditional tightening device, simplifies the mechanism of the tightening device, reduces the size of the device, saves the manufacturing cost, improves the automation degree of the power tong and reduces the labor intensity of the workers. The triangular chuck is suitable for clamping pipe strings with different diameters. In addition, due to the use of toothless slips, the damage of the tightening device to the sleeve is reduced, the sleeve is protected and the service life of the sleeve is prolonged. Therefore, this new type of magnetic rotary tubing tong has a good application prospect in the up and down operation.
Metal Defect Detection Based on Yolov5
Authors: Wang Kun , Teng Zixuan , Zou Tengyue
Published: March 2022

Metal surface defect detection has been a challenge in the industrial field. The current metal surface defect algorithms target only at a few types of defects and fail to perform well on defects with different scales. In this paper, a large number of metal surface defects are studied based on GC10-DET data set. An improved yolov5 detection network is designed targeting defects of various scales, especially of small-scaled objects, using a specific data enhancement method to regularize and an effective loss function to address data imbalance caused by small-scaled object defects. Finally, the comparative experiment on GC10-DET data set proves the major improvements on accuracy superiority of the proposed method.
Waveform Correlation Analysis Method for Mechanical Characteristics of Circuit Breaker in Intelligent GIS Equipment
Authors: Sang Zhongqing , Gu Xiaodong , Wang Yongxin , Jiang Weiyun , Cheng Wenjuan
Published: March 2022

Gas-insulated electrical appliances (GIS) have the characteristics of small footprint and low cost. Therefore, GIS is widely used in intelligent substations. However, once the GIS fails, there will be shortcomings of long maintenance cycle, which seriously affects the normal life and production activities. Based on this, on the basis of summarizing and analyzing the GIS intelligent technology, this paper studies the correlation analysis method of the mechanical characteristic waveform of the intelligent GIS equipment circuit breaker from the aspects of equipment intelligence, device development and software development,corresponding theoretical guidance is provided for the practical application of intelligent GIS equipment circuit breakers.
Torque Transmission Law of Wind Turbine Drive System under the Excitation of Uneven Wind Load
Authors: Qian Baiyun , Zhou Kuncheng , Gao Xiaoxia , Liu Wei
Published: March 2022

A random wind speed time history model based on Weibull distribution is constructed. According to the known mean and variance of wind speed, the time fitting curve of random wind speed is obtained through MATLAB simulation method. According to the wind speed range of the actual operation of the wind turbine, the obtained wind speed curve is transformed, and then according to the obtained relationship between the wind speed of the wind turbine and the input torque, the input time-varying torque of the actual operation of the wind turbine is obtained. Establish the rigid shaft model of the wind turbine gearbox, calculate the gearbox transmission ratios at all levels, and then obtain the torque output curves of the gearbox planetary stage, medium-speed stage, and high-speed stage under random wind speed input to study wind power the torque transmission law of the machine drive system. The ability to better analyse the transmission structure of the gearbox and the torque transmission law of key components has a certain significance for the design and manufacture of the wind turbine transmission chain.
Modeling Simulation and Experiment of Wide-range Current Transformer Based on New Nanocrystalline Alloy Material
Authors: Lu Bing , Chen Xiwen , Xu Zhongda , Nie Gaoning , Tang Xiaojun
Published: March 2022

In the traditional electromagnetic current transformer, when the operating current is too large or too small, the measurement error will fluctuate greatly, resulting in a sharp deterioration of the measurement accuracy. In order to solve this problem, the article first established a simulation model, measured the characteristic curve of the new nanocrystalline alloy material, and imported it into the simulation model. Compare the wide-range error conditions of the current transformer; then, use the new nanocrystalline alloy material as the new wide-range current transformer core, adjust the size of the wide-range current transformer core, and increase the diameter of the secondary winding for simulation; Finally, according to the simulation results, a prototype of a new wide-range current transformer is prepared and error tests are carried out. The test results of the experiment show that the primary side of the new wide-range current transformer is within the range of 0.1%-200% of the rated current. The limit of the ratio difference and the angle difference reaches ±0.2% and ±10’, which meets the measurement requirements of class 0.2 current transformers.
A Fuzzy Evaluation Method for the Drivability of New Energy Vehicles Based on Similarity
Authors: Huang Xincheng
Published: March 2022

The purpose of this paper is to propose a fuzzy evaluation method for the drivability of new energy vehicles. This method divides the evaluation processes of the vehicle drivability into two stages. In the first stage, the vehicle drivability test experts describe the importance of each drivability index through linguistic variables, and then the concept of similarity between two triangular fuzzy numbers is used to determine the weights of experts after converting linguistic variables into triangular fuzzy numbers. The weights of indexes are determined according to the combination of subjective and objective weights, in which the objective weights are determined according to the conflict degree between two fuzzy numbers for the rating of importance given by different experts under the same index. In the second stage, for each index, the experienced drivers give the rating of the vehicle drivability, and then calculate the weighted fuzzy value of the drivability indexes according to the indexes weights. The evaluation results are explained by numerical drivability and linguistic drivability. The former is obtained from the total fuzzy drivability through defuzzification, while the latter is determined according to the similarity between the total fuzzy drivability and the fuzzy number for the rating of the drivability. We give a numerical example to evaluate the drivability of three new energy vehicles.