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Machine Learning Techniques in Predicting Hot Deformation Behavior of Metallic Materials

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 713-732页

作者： Petr Opela josef Walek Jaromír Kopecek Department of Metallurgical Technologies Faculty of Materials Science and TechnologyVSB–Technical University of OstravaOstrava70800Czech Republic FZU—Institute of Physics of the Czech Academy of Sciences Prague18200Czech Republic

In engineering practice,it is often necessary to determine functional relationships between dependent and independent *** relationships can be highly nonlinear,and classical regression approaches cannot always provide sufficiently reliable ***,Machine Learning(ML)techniques,which offer advanced regression tools to address complicated engineering issues,have been developed and widely *** study investigates the selected ML techniques to evaluate their suitability for application in the hot deformation behavior of metallic *** ML-based regression methods of Artificial Neural Networks(ANNs),Support Vector Machine(SVM),Decision Tree Regression(DTR),and Gaussian Process Regression(GPR)are applied to mathematically describe hot flow stress curve datasets acquired experimentally for a medium-carbon *** the GPR method has not been used for such a regression task before,the results showed that its performance is the most favorable and practically unrivaled;neither the ANN method nor the other studied ML techniques provide such precise results of the solved regression analysis.

关键词： Machine learning Gaussian process regression artificial neural networks support vector machine hot deformation behavior

Fundamentals of Design and Technology of Rolling Element Bearings

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Chinese Journal of Aeronautics 2010年第1期23卷 123-136页

作者： Franz-josef Ebert FAG Aerospace GmbH & Co.KG D-97421 SchweinfurtGermany

This article presents an overview of fundamentals of rolling element bearing designs and technologies. The aim is to outline the complex interrelation of all fundamentals with the rolling contact fatigue and the attainable bearing life. Such fundamentals include, amongst others, bearing stressing and life capability. The article shows the different types of rolling bearing stressing and the analysis of the stress distribution （principal stresses and equivalent stresses） in the material under the rolling contact area. It becomes obvious that the contamination of the bearing with foreign particles leads to a drastic reduction in bearing life. Furthermore, it demonstrates the impact of the bearing lubrication and coating as well as the effect of additives on the attainable life and wear. Further fundamentals of rolling element bearing de- sign are the materials, the material cleanliness and the heat treatment. The article reveals the importance of the clean- liness of bearing steels as well as different types of inclusions and their effect on rolling contact fatigue. Additionally the article describes how to optimize the material properties （strength, toughness and residual stress） by the heat treat- nlent processes. The outcome of these investigations is that endurance life of a rolling element bearing can be achieved if specific operating conditions, an adequate lubrication, good system cleanliness and specific bearing stressing are met. The article provides a guideline for bearing engineers on how designs and technologies can be applied to optimizing a bearing for a particular industry or aerospace application.

关键词： aerospace rolling contact fatigue endurance life materials heat treatment lubrication reliability

An Overview of Performance Characteristics, Experiencesand Trends of Aerospace Engine Bearings Technologies

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Chinese Journal of Aeronautics 2007年第4期20卷 378-384页

作者： Ebert Franz-josef Sales and Product Development Aerospace FAG Aerospace GmbH & Co. KG Schweinfurt D-97421 Germany

In this paper, the operating conditions, technical requirements, performance characteristics, design ideas, application experiences and development trends of aerospace engine bearings, including material technology, integration design and reliability, are reviewed. The development history of aerospace engine bearing is recalled briefly at first. Then today＇s material technologies and the high bearing performances of the bearings obtained through the new materials are introduced, which play important roils in the aeroengine bearing developments. The integration design ideas and practices are explained to indicate its significant advantages and importance to the aerospace engine bearings. And the reliability of the shaft-bearing system is pointed out and treated as the key requirement with goals for both engine and bearing. Finally, as it is believed that the correct design comes from practice, the pre-qualification rig testing conducted by FAG Aerospace GmbH ＆ Co. KG is briefly illustrated as an example. All these lead to the development trends of aerospace engine bearings from different aspects.

关键词： aerospace engine bearing performance characteristic material technology integrated bearing design reliability system cost

The new approach of standardization of capillary electrophoresis

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Science China Chemistry 2005年第Z1期48卷 14-19页

作者： josef Havel Department of Analytical Chemistry

In this paper, we develope the new standardization methods to eliminate the influence in capillary electrophoresis (CE). The markers were used to determine the basis position and then correct the data of sample by the migration time of standard sample, and make the migration time of samples consistent with the standard sample by the criterion of the marker. The problem of time transition was corrected in this way. Then according to the peak height or peak area of the marker in the sample (peak height was used here) compared with the standard sample, the sample data was zoomed appropriately. The absorbance error was made to be *** wavelet de-noise method was also used to make the data smooth and get a good baseline.

关键词： capillary electrophoresis, standardization, precision, qualitative and quantitative analysis, wavelet transform.

General Solutions of First-Order Algebraic ODEs in Simple Constant Extensions

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Journal of Systems Science & Complexity 2023年第4期36卷 1769-1788页

作者： MITTERAMSKOGLER Johann josef WINKLER Franz Research Institute for Symbolic Computation(RISC) Johannes Kepler Universität LinzA-4040 LinzAustria

If a first-order algebraic ODE is defined over a certain differential field,then the most elementary solution class,in which one can hope to find a general solution,is given by the adjunction of a single arbitrary constant to this *** of this type give rise to a particular kind of generic point—a rational parametrization—of an algebraic curve which is associated in a natural way to the ODE’s defining *** for the opposite direction,we show that a suitable rational parametrization of the associated curve can be extended to a general solution of the ODE if and only if one can find a certain automorphism of the solution *** automorphisms are determined by linear rational functions,i.e.,Möbius *** properties of rational parametrizations,in combination with the particular shape of such automorphisms,lead to a number of necessary conditions on the existence of general solutions in this solution ***,the desired linear rational function can be determined by solving a comparatively simple differential system over the ODE’s field of *** results hold for arbitrary differential fields of characteristic zero.

关键词： Algebraic curve algebraic differential equation general solution Möbius transformation rational parametrization

Impact of neighborhood features on housing resale prices in Zhuhai (China) based on an (M)GWR model

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Big Earth Data 2023年第1期7卷 146-169页

作者： Nianhua Liu josef Strobl Interfaculty Department of Geoinformatics-Z_GIS University of SalzburgSalzburgAustria Department of Geoinformatics PalackýUniversity OlomoucOlomoucCzech Republic

The paper aims at exploring the relationship between housing resale prices and neighborhood features in Zhuhai,as well as structure and location *** neighborhood features are collected to analyze their influence on average community-level apartment resale prices in *** neighbor-hood features,structural and location characteristics,are selected according to their statistical significance and multi-collinearity test results from an OLS *** analysis is performed by OLS,GWR,and MGWR to compare their per-formance in housing price research at community *** comparison of the three models also demonstrates that the GWR(66%)and MGWR(68%)models perform much better than OLS model(52%).MGWR is not significantly different from GWR in areas with few sample points,and the optimal bandwidth at different spatial scales is hard to be captured in a city-level study *** regression parameter indicates that building age is the most important factor among all influen-cing *** to schools and factories have positive and negative significant effects on housing resale prices,*** spatial pattern of neighborhood features is also detected at town *** and MGWR models accurately demonstrate local spatial heterogeneity of the housing resale market,which provides better results than the traditional OLS model in the goodness of fit and parameter estimates when spatial dependency is *** results provide references for local planning departments,helping to reveal the compli-cated relationship and spatial patterns between housing price and determinants over space.

关键词： Housing resale price neighborhood features ordinary least squares multiscale geographically weighted regression

Cluster headache as a manifestation of a stroke-like episode in a carrier of the MT-ND3 variant m.10158T>C

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World Journal of Clinical Cases 2020年第1期8卷 242-244页

作者： josef Finsterer Neurological Department Messerli Institute

In a recent article Fu et al reported about a 52 years old female with a mitochondrial disorder due to the variant m.10158T>C in the mtDNA located gene *** study has a number of *** study would particularly profit from providing more data about multisystem disease,from providing the current medication,the cerebro-spinal fluid findings,the detailed phenotypic presentation,and the genotype of first-degree *** the index patient had experienced recurrent seizures it is crucial to know the current and previous anti-seizure medication as it may strongly determine the *** of them are mitochondrion-toxic and particularly valproic acid may exhibit fatal side *** outcome may also depend on the degree of multisystem involvement why it is crucial to prospectively investigate the patient for subclinical involvement of organs not obviously ***,the outcome of the stroke-like lesions on imaging would be interesting to *** lesions may completely disappear or may end up as white matter lesion,laminar cortical necrosis,focal atrophy,cyst,or as the so-called toenail *** is also a need of discussing more profoundly the imaging findings and their diagnostic significance and to investigate first degree relatives of the index patient clinically and *** highly interesting,the presentation of this case of a mitochondrial disorder lacks clinical and genetic data of the patient and his *** parameters,such as severity of disease,degree of progression,drugs,pathogenicity of the mutation,and multisystem involvement require a profound discussion.

关键词： Heteroplasmy mtDNA Oxidative phosphorylation Stroke-like episode

Impact of agricultural landscape structure on the patterns of bird species diversity at a regional scale

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Avian Research 2023年第4期14卷 600-610页

作者： Denisa Dvorakova Jan Sipos josef Suchomel Department of Zoology FisheriesHydrobiology and ApicultureMendel University in BrnoZemedelska 161300BrnoCzech Republic

The loss of bird species diversity is a crucial problem in the European agricultural *** in the area coverage of major land cover types has been mentioned as one of the main factors responsible for bird biodiversity *** this study,we focused on the impact of landscape matrix characteristics on bird species richness and on Faith’s phylogenetic diversity index on a spatial scale of 1000-m radius around the measured occurrence *** investigated how land cover composition affects bird diversity on the landscape scale using nationwide citizen science *** total,168,739 records of bird occurrence in the South Moravian Region of the Czech Republic during growing season from 2009 to 2019 were *** found that the presence of water bodies and wetlands significantly corresponded to the areas of highest bird species *** also revealed that the presence of forests(~60%of the forest in the Czech Republic is occupied by commercial forests),urban areas and arable land were negatively associated with bird species richness and phylogenetic ***(both coniferous and deciduous)and urban habitats were found to have a tendency to host a clustered phylogenetic community structure in comparison with wetland and arable land.A strong negative association between forest proportion and bird diversity led us to conclude that the expansion of the forest(with simple species composition,horizontal and vertical structure)could be one of the critical drivers of the decline of bird species diversity in the European agricultural *** the other hand,our results also pointed out that small woody features(i.e.,woodlots)and scattered woodland shrub vegetation were one of the main landscape characteristics supporting a bird diversity in rural *** is in concordance with other studies which mention these landscape structures as important elements for nesting and foraging of farmland *** thus recommend to maintain and restor

关键词： Bird occurrence Citizen science Conservation Landscape influence Phylogenetic diversity Spatial heterogeneity

Weak influence of natural vegetation in urban green spaces compared to agricultural ecosystems on House Martin populations:Insights from nationwide citizen science data in the Czech Republic

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Avian Research 2024年第2期15卷 139-146页

作者： Denisa Dvorakova Jan Sipos josef Suchomel Department of Zoology FisheriesHydrobiology and ApicultureMendel University in BrnoZemedelska 161300BrnoCzech Republic

The House Martin(Delichon urbicum)is a common farmland bird species in the European landscape,yet its population numbers are currently in ***,it is not yet sufficiently explained why this long-term decline *** fill this gap in our knowledge,we investigated how land cover composition affects the abundance of House Martins on the landscape scale by using nationwide citizen science *** a generalised linear mixed-effect model(GLMM),we evaluated 12,094 records from the Czech Republic spanning *** analysis underscores the significance of land cover type in shaping House Martin *** specifically,our results indicate that within agricultural land covers“naturally managed arable lands”exhibited significant positive effect,while forests,orchards,and vineyards were deemed less favourable for House Martin *** urban land covers,we found a clear distinction in the impact on House Martin populations,with a positive effect observed in urban infrastructure,development areas,and post-industrial sites(i.e.,UrbanAreas),while an indifferent impact was noted within urban green spaces and landscaped areas(i.e.,GreenUrban).Notably,our findings suggest that the simple spatial,age,and species structure typical of forests in Europe,and similarly,the uniform structure of parks and gardens,may be responsible for the decline in the abundance of the House *** advocate for the preservation or enhancement of urban greenery,expansion of natural vegetation in rural areas and adoption of ecological management practices in orchards and vineyards to mitigate further declines in House Martin populations.

关键词： Citizen science Habitat preferences House Martin Species distribution Urban and suburban landscape