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Harmonics in the squirrel Cage Induction Motor Analytic Calculation Part III: Influence on the Torque-speed Characteristic

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CEs Transactions on Electrical Machines and systems 2024年第1期8卷 86-102页

作者： G.kovács the Ganz Electric Works BudapestHungary

The harmonics that appear in the squirrel cage asynchronous machine have been discussed in great detail in the literature for a long time. However, the systematization of the phenomenon is still pending, so we made an attempt to fill this gap in the previous parts of our study by elaborating formulas for calculation of parasitic torques. It was a general demand among those who work in this field towards the author to verify his formulas with measurements. In the literature, it seems,only one detailed, purposeful series of measurements has been published so far, the purpose of which was to investigate the effect of the number of rotor slots on the torque-speed characteristic curve of the machine. The main goal of this study is to verify the correctness of the formulas by comparing them with the referred series of measurements. Relying on this, the expected synchronous parasitic torques were developed for the frequently used rotor slot numbers-as a design guide for the ***, together with our complete table for radial magnetic pull published in our previous work, the designer has all the principles, data and formulas available for the right number of rotor slots for his given machine and for the drive system. This brings this series of papers to an end.

关键词： Asynchronous parasitic torques Induction motor squirrel cage rotor space harmonics synchronous parasitic torques

Harmonics in the squirrel Cage Induction Motor Analytic Calculation-Part Ⅰ: Differential Leakage, Attenuation, Asynchronous Parasitic Torques

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CEs Transactions on Electrical Machines and systems 2023年第4期7卷 320-329页

作者： G.kovács Ganz Electric Works 1095 BudapestHungary

The magnetic field generated in the air gap of the cage asynchronous machine and the harmonics of the magnetomotive forces creating that magnetic field, as well as the related differential leakage, attenuation, asynchronous parasitic torques have been discussed in great detail in the literature, but always separately, for a long time. However, systematization of the phenomenon still awaits. Therefore, it is worth summarizing the completeness of the phenomena in a single study – with a new approach at the same time-in order to reveal the relationships between them. The role of rotor slot number is emphasized much more than before. An existing, commonly used, but still impractical basic figure has been modified to more clearly demonstrate the response of the rotor for the harmonics of the stator. The need to treat differential leakage, asynchronous parasitic torques and attenuation together will be demonstrated: new formula for asynchronous parasitic torque is derived;the long-used characteristic curves for differential leakage and attenuation used separately so far was merged into one, correct curve in order to provide a correct design guide for the engineers.

关键词： Asynchronous parasitic torque Attenuation Differential leakage squirrel cage induction motor Winding harmonics

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Improving ecosystem services in farmlands:beginning of a long-term ecological study with restored flower-rich grasslands

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Ecosystem Health and sustainability 2022年第1期8卷 399-405页

作者： andrás Báldi Raoul Pellaton Áron Domonkos Bihaly Viktor szigeti Eszter Lellei-kovács andrás Máté Miklós sárospataki Zoltán soltész Lászlósomay Anikókovács-Hostyánszki Lendület Ecosystem services Research Group Institute of Ecology and BotanyCentre for Ecological ResearchVácrátótHungary Department of Zoology and Ecology Institute of Wildlife Management and Nature ConservationHungarian University of Agriculture and Life SciencesGödöllőHungary Dorcadion Ltd KecskemétHungary

Biodiversity declines in an unprecedented way,mostly due to land use *** interventions proved to be one of the most effective tools to halt the decline,especially in ecosystems such as agricultural ***-based,locally adapted recommendations on grassland restoration,however,are often missing,so we present a novel approach for such interventions that can be implemented anywhere and that are based on scientific *** a recently started long-term field ecological study,we established 0.5 ha wildflower parcels,using a diverse local seed mixture of 32 insect-visited plant species in Central European agricultural landscapes in *** focus is on the landscape-scale effects of this ecological intensification on ecosystem services such as crop yield,pollination and pest control,and the long-term monitoring of the successional *** aim is to showcase an effective restoration protocol that could serve as a model for future farm management,and provide much-needed evidence for policy on landscape ecological restoration of international relevance.

关键词： Ecological intensification field experiment protocol restoration wildflower strip

Complications in children with percutaneous endoscopic gastrostomy (PEG) placement

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World Journal of Pediatrics 2019年第1期15卷 12-16页

作者： Brigitta Balogh Tamás kovács Amulya Kumar saxena Division of Pediatric surgery Department of PediatricsUniversity of SzegedKorányi fasor 14-15Szeged 6725Hungary Department of Pediatric surgery Chelsea Children's HospitalChelsea and Westminster NHS Fdn TrustImperial College LondonLondonUK

Introduction The aim of this study was to analyze the complication rates and mortality in association with different operative techniques of percutaneous endoscopic gastrostomy (PEG),age,underlying diseases and other risk ***,analysis of the indications of PEG insertion and the underlying comorbidities was also *** This study performs a literature analysis of PEG-related complications in *** was searched on PubMed(R) (1994-2017) using terms 'percutaneous endoscopic gastrostomy','complications','mortality' and 'children'.Results Eighteen articles with 4631 patients were *** mean age was 3 years (0-26 years).Operative techniques were:pull technique in 3507 (75.7%),1 stage PEG insertion in 449 (9.7%),introducer technique in 435 (9.4%),image-guided technique in 195 (4.2%) and laparoscopic-assisted PEG in 45 (1.6%).Most frequent indications for PEG insertion were dysphagia (n =859,32.6%),failure to thrive (n =723,27.5%) and feeding difficulties (n =459,17.4%).Minor complications developed in n 1518 patients (33%),including granulation (n =478,10.3%),local infection (n =384,8.3%) and leakage (n =279,6%).In 464 (10%) patients,major complications occurred;the most common were systemic infection (n =163,3.5%)and cellulitis (n =47,1%).severe complication like perforation occurred in less than 0.3%.Patients with lethal outcomes (n =7,0.15%) had severe comorbidities;and the cause of mortality was sepsis in all *** or young age did not affect complication *** with ventriculoperitoneal (VP) shunt had higher risk of major *** high-risk patients,laparoscopic-assisted PEG insertion had less major and severe complication than traditional pull *** PEG is a safe operative technique;although minor complications are relatively common and occur in up to 1/3 of patients,there is a fairly low rate of severe ***-thirds of PEG patients have at least one ***

关键词： Children Complications Percutaneous endoscopic gastrostomy

Presence of Fleischer ring and prominent corneal nerves in keratoconus relatives and normal controls

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International Journal of Ophthalmology(English edition) 2015年第5期8卷 922-927页

作者： gnes Kriszt Gergely Losonczy andrs Berta Lili Takcs Department of Ophthalmology University of Debrecen Clinical Center

AIMTo examine the occurrence of commonly known clinical signs of keratoconus (KC), i.e. Fleischer ring, prominent corneal nerves and thinning, among unaffected family members of KC patients and healthy control *** of both eyes of 117 relatives of KC patients having no manifest disease based on videokeratography indices (KC relatives), and 142 controls were used for Pearson correlation and t-test statistics. Correlation of Fleischer ring, prominent corneal nerves and central pachymetry data were tested with each other and with videokeratography indices (KsI, KIsA, 3 and 6 mm Fourier asymmetry, and I-s).REsULTsA moderate correlation was found between Fleischer ring and all examined topographical indices. Most important correlation was present with 6 mm Fourier asymmetry, and corneal pachymetry (r=0.272, Pspectively). similar correlations were found with prominent corneal nerves (r=0.234, Psymmetry and r=-0.235, P=0.0265 for pachymetry). KC family members who exhibited Fleischer ring or prominent nerves had thinner and more asymmetric corneas than those without Fleischer ring or prominent corneal nerves (Ps with t-test and Mann-Whitney rank sum test). Though rarely, Fleischer ring and prominent corneal nerves occurred among normal controls, indicating the existence of forme fruste cases in the normal population. Control subjects, who had corneal Fleischer ring or prominent nerves had corneas more similar to KC than other controls (t-test: increased KsI and KIsA, P=0.048 and 0.012, respectively).CONCLUsIONIn KC family members and healthy individuals, Fleischer ring and prominent corneal nerves are associated with features of KC and may suggest a possibility of forme fruste KC. searching for the possible presence of Fleischer ring or prominent nerves on the cornea may help in the decision whether or not to diagnose subclinical KC in

关键词： forme fruste/subclinical keratoconus Fleischer ring corneal nerves corneal thinning videokeratographic indices iatrogenic keratectasia

Touristic urbanization and greening of coastal dune fields:A long-term assessment of a temperate sandy barrier of Argentina

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Journal of Geographical sciences 2025年第1期 206-230页

作者： GARZO Pedro andrés DADON José Roberto IsLA Federico Ignacio Instituto de Investigaciones Marinas y Costeras (IIMyC-CONICET/UNMDP) Instituto de Geología de Costas y del Cuaternario Dr.Enrique J.schnack (IGCC-CIC/UNMDP) Universidad de Buenos Aires Facultad de Arquitectura Dise?o y Urbanismo Centro de Investigaciones Gestión de Espacios Costeros (GEC-FADU/UBA) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)

Dune barrier systems represent highly sought-after coastal landscapes for tourism and urban development around the world. However, a century ago, they were considered hazardous environments due to their great dynamic nature. As a result, stabilization practices were considered necessary. The systematic introduction of fast-growing exotic trees helped stabilize the sand, making it easier for tourism urbanization to take place, but also leading to erosion processes. This paper aims to assess long-term changes in vegetation cover over a large temperate barrier in Argentina. This complex region includes urban resorts, afforestation zones, and protected areas. A GIs-based geospatial analysis was conducted using a large satellite database(> 350 images), and the future evolution of the vegetation was modeled. The results revealed two primary spatiotemporal patterns associated with a gradual expansion of vegetation cover, accompanied by a concurrent reduction in sandy areas. In 1986, the dune area comprised 75% more surface than vegetation, whereas in 2021, it represented 60% less than vegetation. Furthermore, the 2050 scenario suggests a potential 40% reduction of dunes in certain areas. It is necessary to enhance management actions aimed at maintaining dune mobility and ensuring local and regional sediment balance. Long-term management strategies must focus on restoring native plant communities and controlling invasive species, and avoiding new dune fixation initiatives based on the introduction of exotic species.

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On Non-normal Arc-Transitive 4-Valent Dihedrants

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Acta Mathematica sinica,English series 2010年第8期26卷 1485-1498页

作者： István kovcs Botjan KUZMAN Aleksander MALNI FAMNIT University of Primorska PeF University of Ljubljana IMFM University of Ljubljana

Let X be a connected non-normal 4-valent arc-transitive Cayley graph on a dihedral group Dn such that X is bipartite, with the two bipartition sets being the two orbits of the cyclic subgroup within Dn. It is shown that X is isomorphic either to the lexicographic product Cn[2K1] with n 〉 4 even, or to one of the five sporadic graphs on 10, 14, 26, 28 and 30 vertices, respectively.

关键词： Cayley graph arc transitivity dihedral group

Isomorphisms of Cubic Cayley Graphs on Dihedral Groups and sparse Circulant Matrices

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Acta Mathematica sinica,English series 2023年第4期39卷 618-632页

作者： Istvan kovAcs UP IAM&FAMNIT University of PrimorskaMuzejski trg 26000 KoperSlovenia

We show that,up to isomorphism,there is a unique non-CI connected cubic Cayley graph on the dihedral group of order 2n for each even number n≥*** answers in the negative the question of Li whether all connected cubic Cayley graphs are CI-graphs(Discrete Math.,256,301-334(2002)).As an application,a formula is derived for the number of isomorphism classes of connected cubic Cayley graphs on dihedral groups,which generalises the earlier formula of Huang et *** with the particular case when n is a prime(Acta ***.,***.,33,996-1011(2017)).As another application,a short proof is also given for a result on sparse circulant matrices obtained by Wiedemann and Zieve(arXiv preprint,(2007)).

关键词： Cayley graph graph isomorphism dihedral group circulant matrix

Hyperactive learning for data-driven interatomic potentials

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npj Computational Materials 2023年第1期9卷 599-612页

作者： Cas van der Oord Matthias sachs Dávid Péter kovács Christoph Ortner Gábor csányi University of Cambridge Cambridge CB21PZUK University of Birmingham Birmingham B152TTUK University of British Columbia VancouverBC V6T 1Z2Canada

Data-driven interatomic potentials have emerged as a powerful tool for approximating ab initio potential energy *** most time-consuming step in creating these interatomic potentials is typically the generation of a suitable training *** aid this process hyperactive learning(HAL),an accelerated active learning scheme,is presented as a method for rapid automated training database *** adds a biasing term to a physically motivated sampler(*** dynamics)driving atomic structures towards uncertainty in turn generating unseen or valuable training *** proposed HAL framework is used to develop atomic cluster expansion(ACE)interatomic potentials for the Alsi10 alloy and polyethylene glycol(PEG)polymer starting from roughly a dozen initial *** HAL generated ACE potentials are shown to be able to determine macroscopic properties,such as melting temperature and density,with close to experimental accuracy.

关键词： starting generating consuming