bluuebunny/crossref_metadata_2025_split huggingface dataset:
Space charge dynamics in epoxy resin under voltage polarity reversal at various temperatures
Authors: Liu Peng , Zhang Hongliang , Zhang Siyu , Su Xialin , Xie Zongliang , Peng Zongren 
Published: December 2020

AbstractEpoxy resin has been used to cast the core of the dry‐type high voltage direct current bushings and can accumulate space charge under high electric fields at high temperatures, which is believed to be a potential threat to the safe operation of dry bushings, especially under polarity reversal. In this study, results of a study of the evolution of space charge and electric field distribution in epoxy resin, under polarity reversal at 10 and 20 kV/mm, and at temperatures between 40 and 100°C, are presented. The results show that the space charge dynamics in epoxy resin during the test were different at various temperatures. At temperatures no more than 60°C, space charge accumulation within the samples was not obvious. Instead, a low‐frequency dielectric relaxation process maybe occurs during the polarity reversal, which made the charge peaks on the electrodes after the reversal were slightly smaller than those before the reversal. At temperatures no less than 80°C, considering that the applied electric field has little effect on the barrier reductions of the traps within the samples, the space charge dynamics were mainly governed by a thermally activated process, and the depths of the deepest occupied traps were obtain by analysing the transient processes.
Characterization of magnetic field waveforms from triggered lightning attached on transmission line at 18 m, 130 m and 1.55 km
Authors: Cai Li , Li Jin , Wang Jianguo , Zhou Mi , Li Quanxin , Fan Yadong 
Published: December 2020

AbstractThe authors present a statistical analysis of characteristics of magnetic fields at different distances from triggered lightning experiments on Transmission Line at Guangdong Comprehensive Observation Experiment on Lightning Discharge during the summer of 2019. The histograms and parameters of statistical distributions for the following 22 waveform characteristics are presented, including current peak, 10%–90% risetime, half‐peak width and steepness, leader magnetic field peak, return‐stroke magnetic field peak, magnetic field peak, 10%–90% risetime, half‐peak width and steepness at 15 m, 130 m and 1.55 km. The arithmetic mean of 48 return stroke current peaks is 18.3 kA and the geometric mean is 17.0 kA. The arithmetic and geometric means of the current 10%–90% risetime are 0.6 and 0.6 μs, respectively. The leader magnetic field, return‐stroke magnetic field and magnetic field peak at 18 m, 130 m and 1.55 km are shown linear relationship with current peak values. With increasing the distance(r), the magnetic field peak value decrease, combining the magnetic field characteristics reported by previous studies, the analysis of all magnetic field peaks in different distances suggest linear relationship with r
−0.90. The magnetic field 10%–90% risetime shows linear relationship with ln(r) and half‐peak width did not show significant correlation with distance.
Research on 3‐D total electric field of crossing high voltage direct current transmission lines based on upstream finite element method
Authors: Ma Xiaoqian , Xie Li , He Kun , Lu Jiayu 
Published: December 2020

AbstractThe ongoing large‐scale construction of ultra high voltage direct current projects in China makes the crossing of two high voltage direct current (HVDC) lines inevitable. It is critical to study the characteristics and calculation method of 3‐D total electric fields of crossing HVDC lines. The problems encountered when applying the 3‐D upstream finite element method to calculate total electric field of crossing HVDC lines and the solutions are studied in this study. In view of the surface electric field varying greatly along longitudinal direction of conductors, the calculation method adopting the Davidon‐Fletcher‐Powell optimization algorithm is introduced to realize the fast computation of 3‐D space‐charge‐free field. Considering the distinct corona intensity at different positions of conductors, a new formula for initializing charge density is studied to ensure the convergence of calculation process. Considering the large computation amount of total electric field, an adaptive iteration strategy is put forward to effectively speed up the calculation. The measurement of ground total electric field underneath a crossing HVDC test line is conducted to verify the validity of the proposed calculation method. The distribution characteristics of electric fields of crossing HVDC lines are calculated and analysed. The research results will provide technical support for the design and environmental impact assessment of crossing HVDC transmission lines.
Spatially continuous transformer online temperature monitoring based on distributed optical fibre sensing technology
Authors: Liu Yunpeng , Li Xinye , Li Huan , Yin Junyi , Wang Jiaxue , Fan Xiaozhou 
Published: December 2020

AbstractTransformer internal thermal monitoring exists huge blind areas, and it is difficult for traditional methods to get fully distributed temperature in real time. In this contribution, the distributed optical fibre sensor was creatively applied inside an operating 35 kV oil‐immersed transformer which is also qualified for actual power grid operation through the ex‐factory tests. Furthermore, the full‐region temperature along the windings and iron limbs were firstly monitored in a spatiotemporally continuous manner and the hotspots were also closely traced, fluctuating at 90% of the high‐voltage winding height (80% for low‐voltage winding) during the whole process of the heat‐run test. Corresponding Finite Element Method (FEM) for thermo‐fluid field calculation was then utilized for deeper analysis. On the former basis, the actual detected temperature distributions (both spatial and temporal) were compared with the International Electrotechnical Commission traditional model and some modifications were suggested based on the real time measured data. This novel online monitoring application and the detailed internal thermal information may provide a solid reference for the delicate management of power transformers, which also offers a new horizon for the online monitoring in electrical apparatus industry.
On the charged aerosols generated by atmospheric pressure non‐equilibrium plasma
Authors: Zhang Yanzhe , Cheng He , Gao Haotian , Liu Dawei , Lu Xinpei 
Published: December 2020

AbstractRecently, charged aerosols are used widely in many applications, such as fog elimination, inactivation of airborne viruses and so on. Atmospheric pressure non‐equilibrium plasma (APNP) have become an efficient way to generate charged aerosols. Except the traditional pin‐plate or wire‐plate APNP sources, the new APNP sources such as large scale corona discharge system and air plasma jet array are introduced. These sources can increase the ion density in open air and generate adjustable large plasma plume, which are helpful in increasing the charging efficiency on aerosols. Although the interactions between plasma and aerosols is quite complicated, the preliminary study suggests that the diffusion charging dominates aerosols below 0.1 μm, field charging dominates aerosols larger than 1 μm, and the photo charging also contributes to aerosols charging. These reactive charged aerosols have shown their potential in the artificial rain enhancement, biomedicine, and material processing. Finally, challenges and opportunities for theoretical, experimental, and application research in related cross‐disciplinary areas are presented to stimulate critical discussions and collaborations in the future.
Mobility‐limited charge injection in cross‐linked polyethylene under extra high electric field
Authors: Zhu Xi , Yin Yi , Peng Suman , Wu Jiandong , Li Wenpeng , Chen Xin , Li Zhenyu , Guan Jianxin 
Published: December 2020

AbstractIn this study, characteristics of charge injection under extra high electric field (above 100 kV/mm) in cross‐linked polyethylene (XLPE) were investigated by experiments of conduction current and space charge. The results show that current density from low electric field to sample breakdown corresponds to space charge limited current (SCLC) theory. More specifically, Schottky current is similar to experiment current before 100 kV/mm, while the J–E curve conforms to a modified SCLC theory after 100 kV/mm. Besides, the non‐linear coefficient of J–E curve from 100 kV/mm to extra high electric field is smaller than theoretical value, and the injection depth of space charge is restricted as the field becomes higher than 100 kV/mm, which may be caused by the negative differential mobility of charge. Driven by extra high electric field, charge collides with lattice of dielectric and scatters. As a result, mean free time of charge decreases and charge mobility is reduced with the increased field. Consequently, considering the decrease in charge mobility, a mobility‐limited charge injection equation is proposed, and the validity of the proposed equation under extra high electric field is demonstrated by space charge simulation.
Underwater image restoration: A state‐of‐the‐art review
Authors: Fayaz Sheezan , Parah Shabir A. , Qureshi G. J. , Kumar Vijaya 
Published: December 2020

AbstractUnderwater imaging is one of the hot areas of research and is receiving considerable attention from the research community due to the challenges involved. Underwater images are prone to various distortions like poor contrast and colour deviation. Light scattering and light absorption in water medium are the main reasons for degradation in subaquatic images. Scattering of visible‐light energy reduces the sharpness of image whereas varying degrees of light attenuation travelling in water results in the colour change. Restoration of distorted underwater images is an ill‐posed and challenging problem. Various techniques and methodologies are being used to process and restore underwater images. In this study, we present a state‐of‐the‐art review of various conventional and computer vision‐based algorithms and techniques, developed so far, to present a clearer view of the methods used for underwater image restoration. We discuss various conditions for which the schemes have been developed as well as highlight the quality assessment methods used to evaluate their performance. We compare various state‐of‐art schemes based on various subjective and objective indices and discuss future research directions in the field of underwater image restoration.
An upgraded fruit fly optimisation algorithm for solving task scheduling and resource management problem in cloud infrastructure
Authors: Loheswaran K. 
Published: December 2020

AbstractIn this manuscript, an upgraded Fruit Fly Optimization Algorithm (FFOA) is proposed for optimising task scheduling and resource management processes. The proposed FOA algorithm is utilized to address the issues. In the proposed algorithm, every solution is represented by fruit fly. Every fruit fly upgrades their status through well‐organized smell search process. First, a basic approach is put forward to allocate every task for numerous resources and execution time is measured for every task. Second, the overloaded virtual machines (VMs) are identified and the load is balanced to obtain optimal system resource utilisation. The ability of Fly Task Scheduling Algorithm is to schedule the VMs execution time of tasks is minimal. The results of the Fruit Fly‐based algorithms such as Fruit Fly Task Scheduling Algorithm, Modified Fruit Fly Task Scheduling Algorithm, Improved Fruit Fly Task Scheduling Algorithm and Multi‐Swarm Fruit Fly Task Scheduling Algorithm (MSFFTSA) are proposed and analysed. The upgraded Fruit Fly Optimization algorithm of MSFFTSA is compared with different Fruit Fly algorithms. Finally, the proposed algorithm is compared with other algorithms and the experimental results shows that the proposed MSFFTSA technique is better than the other algorithms of the fruit fly algorithms.
Study on influence factors and restraining measures of composite insulator end heating caused by housing microstructure defects
Authors: Zhang Sida , Liao Ruijin , Cheng Li , Zhang Fuzeng , Zeng Xiangjun , Wang Tingting 
Published: December 2020

AbstractIn recent years, the quantity and proportion of heating defects have increased significantly with more composite insulators used in transmission lines and deterioration of early composite insulators. End heating is the main characteristic of this kind of defect in high‐temperature and high‐humidity areas. In this paper, microstructures of the housing material were observed through scanning electron microscopy and the key factors leading to temperature rise were studied through water absorption and power loss experiments. The results show that polarisation loss is the main cause of temperature rise and power loss increases exponentially with higher electric field intensity. The microporous structures of the housing material not only enhance the moisture absorption effect, but also affect the uniform distribution of the electric field. Due to the concentration of the local electric fields at high‐voltage end, the effect of porosity on temperature rise is more significant. By adjusting the shielding depth (i.e. installation height) of grading ring or adding a racetrack ring to restrain electric field intensity at high‐voltage end of composite insulator, the temperature rise in high‐humidity areas can be effectively reduced.
Parameterized reconstruction with random scales for radio synthesis imaging
Authors: Zhang L. , Mi L. G. , Zhang M. , Liu X. , Xu L. , Wang F. , Ruan Y. J. , Li D. Y. 
Published: December 2020

Context. In radio interferometry, incomplete sampling results in a dirty beam with side lobes, which obscures the celestial structures. Before the astrophysical analysis, the effects of the dirty beam need to be eliminated, which can be solved with various deconvolution methods.
Aims. Diffuse astronomical sources observed by modern high-sensitivity telescopes tend to be complex morphological structures, often accompanied by faint features, which are submerged under the side lobes of the dirty beam. We propose a new deconvolution algorithm called random multiscale estimator (RMS-Clean), which is mainly used to solve the difficult reconstruction of diffuse astronomical sources.
Methods. RMS-Clean models the sky brightness distribution as a linear combination of random multiscale basis functions whose scales are obtained by randomly perturbing a preset multiscale list. Random multiscale models are used to approximate the uncertain characteristics of the scales of complex astronomical sources.
Results. When the RMS-Clean method is applied to simulations of SKA observations with realistic diffuse structures, it can reconstruct diffuse structures well and provides a competitive result compared to the commonly used deconvolution algorithms.
Prominence formation by levitation-condensation at extreme resolutions
Authors: Jenkins J. M. , Keppens R. 
Published: December 2020

Context. Prominences in the solar atmosphere represent an intriguing and delicate balance of forces and thermodynamics in an evolving magnetic topology. How this relatively cool material comes to reside at coronal heights, and what drives its evolution prior to, during, and after its appearance, remains an area full of open questions.
Aims. We here set forth to identify the physical processes driving the formation and evolution of prominence condensations within 2.5D magnetic flux ropes. We deliberately focus on the levitation-condensation scenario, where a coronal flux rope forms and eventually demonstrates in situ condensations, revisiting it at extreme resolutions down to order 6 km in scale.
Methods. We perform grid-adaptive numerical simulations in a 2.5D translationally invariant setup, where we can study the distribution of all metrics involved in advanced magnetohydrodynamic stability theory for nested flux rope equilibria. We quantify in particular convective continuum instability (CCI), thermal instability (TI), baroclinicity, and mass-slipping metrics within a series of numerical simulations of prominences formed via levitation-condensation.
Results. Overall, we find that the formation and evolution of prominence condensations happens in a clearly defined sequence regardless of resolution, with background field strength between 3 and 10 Gauss. The CCI governs the slow evolution of plasma prior to the formation of distinct condensations found to be driven by the TI. Evolution of the condensations towards the topological dips of the magnetic flux rope is a consequence of these condensations initially forming out of pressure balance with their surroundings. From the baroclinicity distributions, smaller-scale rotational motions are inferred within forming and evolving condensations. Upon the complete condensation of a prominence ‘monolith’, the slow descent of this plasma towards lower heights appears consistent with the mass-slippage mechanism driven by episodes of both local current diffusion and magnetic reconnection.
„Smartphone addiction”: Fakt oder Fiktion?
Authors: Wolf Nadine D. , Wolf Robert C. 
Published: December 2020

ZUSAMMENFASSUNGGegenstand und Ziel In den vergangenen Jahren wurde vermehrt darauf hingewiesen, dass exzessive Smartphone-Nutzung Merkmale abhängigen Verhaltens aufweisen und damit auch einen eigenständigen Störungswert erlangen kann. In diesem Kontext wurde der Begriff der „smartphone addiction“ eingeführt. In dieser Übersicht soll der aktuelle Wissensstand zu diesem neuen Phänomen zusammengefasst werden.Material und Methoden Selektive Literaturrecherche zur „problematischen“ oder „exzessiven“ Smartphone-Nutzung resp. „smartphone addiction“ unter Berücksichtigung aktueller Befunde aus der Neurobildgebung.Ergebnisse Die „smartphone addiction“ (SPA) kann psychometrisch reliabel erfasst werden. Konservative Schätzungen gehen von einer Prävalenz von ca. 14–31 % bei Jugendlichen und jungen Erwachsenen aus. Die SPA scheint mit vielfältigen anderen Symptomen assoziiert zu sein, insbesondere mit Angst, Depressivität, Impulsivität, Emotions- und Selbswertregulati onsdefiziten. Rezente Befunde der Neurobildgebung verweisen auf neurobiologische Parallelen zu anderen substanzgebundenen und substanzunabhängigen Suchterkrankungen.Schlussfolgerung/klinische Relevanz Die SPA ist ein relativ neues Phänomen, jedoch keine eigenständige Krankheitsentität. Parallelen zur DSM-5 „Internet Gaming Disorder“ (IGD) sind nicht zu übersehen, und möglicherweise könnte die SPA als „mobile“ Variante digitaler Spielstörungen betrachtet werden. Erste neurobiologische Befunde konnten das kategoriale Konstrukt der SPA validieren mit Verweis auf Gehirnregionen und neuronale Netzwerke, die Sucht und abhängiges Verhalten aufrechterhalten. SPA-spezifische Therapieoptionen sind derzeit nicht verfügbar, sie dürften sich jedoch stark anlehnen an Behandlungsprinzipien der IGD. Präventive und psychoedukative Maßnahmen sollten in der Zukunft gestärkt werden.
Woher kommen Missverständnisse an der Schnittstelle von Hirntod und Organspende?
Authors: Moskopp Dag 
Published: December 2020

ZUSAMMENFASSUNGDer Begriff des Hirntodes wurde in Europa an Einzelfällen seit 1952 allmählich entwickelt. Dies führte 1960 zur ersten konzeptionellen Umsetzung mit konsekutivem Abschalten des Respirators 41. Die erste Transplantation mit postmortaler Organspende bei schlagendem Herzen erfolgte 1963 4, 5. Meine historische Darstellung in dieser Zeitschrift 28 wurde kürzlich ebenda kritisiert 9, mit der These, dass ein „Konzept des Hirntodes … maßgeblich“ erst von den Interessen der Transplantationsmedizin „propagiert“ worden – und erst ab 1968 wahrzunehmen sei 1, 18. Die vorliegende Ergänzung beschäftigt sich mit Missverständnissen und Kommunikationsproblemen, die das Thema Hirntod – insbesondere an der Schnittstelle zur postmortalen Organspende – seit Anbeginn begleiten. Philosophische und religionswissenschaftliche Aspekte werden angesprochen, und weitere historische Details erörtert. Schließlich wird am Beispiel auf eine „Intra-vitale“-Hirnautolyse bei richtlinienkonform festgestelltem Hirntod hingewiesen 26, 27, 39, 42–46.
Genomic Landscape and Targeted Treatment of Gallbladder Cancer: Results of a First Ongoing Prospective Study
Authors: Patel Amol , Soneji Dharmesh , Singh Harinder Pal , Kumar Manish , Bandyopadhyay Arnab , Mathur Ankit , Sharma Anuj , Gahlot Gaurav Prakash Singh , MS Shivashankara , Guleria Bhupesh , Nair Rajesh , Bhuva Dipen , Pandalanghat Suresh 
Published: December 2020

Abstract
Background Prognosis of gallbladder cancer (GBC) has not changed in the past 20 years. Comprehensive genomic profiling (CGP) carries potential to determine the actionability for multiple targets, including ERBB2, ERBB3, MET, ROSI, FGFR, and PIK3. This study evaluates the role of CGP and targeted therapies.
Methods This is a multicenter, prospective, single-arm study. All consecutive patients of unresectable and/or metastatic GBC of age ≥18 years were enrolled. Hybrid capture-based CGP was performed by Foundation Medicine CDx. All patients received first-line chemotherapy with gemcitabine–cisplatin regimen. Patients with ERBB2/3 amplification received trastuzumab with capecitabine or nab-paclitaxel, and patients with MET amplification were treated with crizotinib. For ERBB2/3 mutations, lapatinib plus capecitabine regimen was used.
Results Fifty patients were studied with a median age of 56 years (range 26–83) and a male-to-female ratio of 1:1.6. ERBB2 and ERBB3 amplification was seen in 9 (18%) and 2 (4%) patients, respectively. Four patients with ERBB2 amplification received trastuzumab and/or lapatinib, showed partial response, and maintained response beyond 12 weeks. One patient had mixed response, whereas two patients progressed on trastuzumab and lapatinib. Three patients with ERBB3 mutations showed response to lapatinib–capecitabine. One patient with MET amplification responded to crizotinib for 4 weeks. PIK3 mutations were present in 14% of cases and were independent of ERBB aberrations.
Conclusion GBC is enriched in 28% of patients with ERBB2 and ERBB3 amplifications and/or mutations. Responses are seen with lapatinib in concurrent ERBB2 mutation and amplification. ERBB3 mutation showed response to lapatinib. MET and PIK3 are new findings in GBC, which may be targeted.